The present technology relates to track systems and vehicles having track systems.
Certain off-road vehicles, such as all-terrain vehicles (ATVs and UTVs), may be equipped with track systems which enhance their traction and floatation on soft, slippery and/or irregular grounds (e.g., soil, mud, sand, ice, snow, etc.) on which they operate.
For instance, an ATV may be equipped with track systems in place of ground-engaging wheels with tires for which it may have been originally designed.
Replacement of the wheels by track systems provides a larger contact area (patch) on the ground compared to the size of the contact area (patch) of a wheel on the ground. Floatation over soft, slippery and/or irregular ground surfaces is increased and the lower portion of the vehicle is maintained at a greater distance from the ground surface.
Conventionally, track systems comprise a frame, a drive wheel, at least one idler wheel on at least one extremity of the frame, a plurality of support wheels, a tensioner, and an endless track disposed around the drive wheel, the at least one idler wheel, and the plurality of support wheels.
These track systems, while good, are not without their drawbacks. For one, the size of the contact patch also affects the ease of steering the vehicle. On a wheeled or tracked vehicle, the wheels that steer the vehicle are turned about a steering axis defined by the steering system of the vehicle. The contact area of the wheel or track that surrounds the steering axis projected on the ground of the steering wheels opposes, via friction, the rotational movement of the wheel or track about this steering axis. Thus, the larger the contact area on the ground, the more area there is to generate friction which opposes the movement about the pivot point, and the tougher it is to rotate the patch around the steering axis. Therefore, the larger contact area on the ground generated by a track system inherently increases the force needed to steer the vehicle, which is undesirable.
Another difficulty is that some track systems are typically made of components fixedly connected to a frame, which is pivotably connected to the vehicle. This prevents the track systems from following the shape of the uneven ground over which the vehicle is traveling, the traction provided being thus somewhat limited because the contact area of the endless track is not capable of adapting to the ground's imperfections.
In order to reduce the aforementioned drawbacks, there is a desire for a track system and a vehicle that mitigate the above-mentioned issues.
It is therefore an object of the present technology to ameliorate the situation with respect to at least one of the inconveniences present in the prior art.
It is also an object of the present technology to provide a track system and a vehicle having a track system that are improved at least in some instances as compared with some of the prior art.
In the context of the following description, “outwardly” or “outward” means away from a longitudinal center plane of the track system, and “inwardly” or “inward” means toward the longitudinal center plane. In addition, in the context of the following description, “longitudinally” means in a direction parallel to the longitudinal center plane of the track system in a plane parallel to flat level ground, “lateral”, “laterally”, “transverse” and “transversally” means in a direction perpendicular to the longitudinal center plane in a plane parallel to flat level ground, and “generally vertically” means in a direction contained in the longitudinal center plane along a height direction of the track system generally perpendicular to flat level ground. Note that in the Figures, a “+” symbol is used to indicate an axis of rotation. In the context of the present technology, the term “axis” may be used to indicate an axis of rotation. Also, the terms “pivot assembly” and “wheel assemblies” include all the necessary structure (bearing structures, pins, axles and other components) to permit a structure/wheel to pivot/rotate about an axis, as the case may be. Moreover, the direction of forward travel of the track system is indicated by an arrow in
More particularly, according to an aspect of the present technology, there is provided a track system configured to be operatively connectable to a vehicle. The track system defines a longitudinal center plane and is operable on a ground surface. The track system includes a track-engaging assembly that has a frame, a drive wheel, a front idler wheel, a rear idler wheel, a bogie wheel assembly and a plurality of support wheel assemblies. The frame has a front portion, a rear portion, and a lower portion extending vertically below at least one of the front and rear portions. The drive wheel rotationally connected to the frame. The front idler wheel assembly is rotationally connected to the front portion of the frame. The rear idler wheel assembly is rotationally connected to the rear portion of the frame. The bogie assembly is pivotably connected to the lower portion of the frame about a bogie assembly axis extending transversally to the longitudinal center plane, and has a bogie body defining a leading axis, an intermediate axis and a trailing axis. The leading, intermediate and trailing axes extend transversally to the longitudinal center plane and are longitudinally spaced from each other. The plurality of support wheel assemblies include a leading support wheel assembly rotationally connected to the bogie body for rotating about the leading axis, the leading support wheel assembly applying a leading ground force to the ground surface, an intermediate support wheel assembly rotationally connected to the bogie body for rotating about the intermediate axis, the intermediate support wheel assembly applying an intermediate ground force to the ground surface, and a trailing support wheel assembly rotationally connected to the bogie body for rotating about the trailing axis the trailing support wheel assembly applying a trailing ground force to the ground surface. A sum of the leading, intermediate and trailing ground forces define a total ground force applied to the ground surface by the track system. The track system also includes an endless track disposed around the track-engaging assembly, the endless track having a ground-engaging outer side for engaging the ground surface and an inner side opposite to the ground-engaging outer side, the endless track being configured to be drivingly engaged by the drive wheel. The track system has an initial position wherein the total ground force is generally concentrated at the intermediate ground force in response to the track system being at rest on generally a hard and flat level ground surface. In response to the bogie assembly pivoting about the bogie assembly axis, the total ground force is distributed between the intermediate ground force and at least one of the leading and trailing ground forces in response to the track system travelling on a generally hard and uneven ground surface.
In some embodiments, the bogie assembly is pivotably connected to the frame such that the bogie assembly axis is coaxial with the intermediate axis.
In some embodiments, the intermediate axis is disposed longitudinally between the leading axis and the trailing axis.
In some embodiments, a diameter of a wheel of the intermediate support wheel assembly is greater than a diameter of a wheel of at least one of the leading and trailing support wheel assemblies.
In some embodiments, the intermediate axis is vertically lower than at least one of the leading axis and trailing axis.
In some embodiments, the leading, intermediate and trailing support wheel assemblies are substantially aligned in a direction transversal to the endless track.
In some embodiments, at least one of the leading, intermediate and trailing support wheel assemblies includes more than one wheel assembly in a direction transversal to the endless track.
In some embodiments, the leading axis and the trailing axis are respectively spaced from the intermediate axis by a first distance and a second distance.
In some embodiments, a distance ratio of the first distance over the second distance is 1.
In some embodiments, a distance ratio of the first distance over the second distance is smaller than 1.
In some embodiments, a distance ratio of the first distance over the second distance is greater than 1.
In some embodiments, wherein the total ground force is distributed between the leading ground force and the trailing ground force according to the distance ratio in response to the leading support wheel assembly climbing on an obstacle of the ground surface or in response to the trailing support wheel assembly descending an obstacle of the ground surface.
In some embodiments, a magnitude of the leading ground force is greater than a magnitude of the trailing ground force in response to the vehicle accelerating.
In some embodiments, a magnitude of the leading ground force is lower than a magnitude of the trailing ground force in response to the vehicle decelerating.
In some embodiments, the front idler wheel assembly and the rear idler assembly are positioned above the hard and flat level ground surface.
In some embodiments, an approach angle between the endless track and the hard and flat level ground surface in front of the leading support wheel assembly is substantially equal to a departure angle between the endless track and the hard and flat level ground surface behind the trailing support wheel assembly.
In some embodiments, the track system further includes a tensioner associated with one of the front idler wheel assembly and the rear idler wheel for maintaining a tension of the endless track constant notwithstanding pivotal movement of the bogie assembly.
In some embodiments, the track system further includes a slide member extending adjacent to the plurality of support wheel assemblies, the slide member being spaced from the inner side of the endless track by a gap.
In some embodiments, the slide member is connected to the frame.
In some embodiments, the slide member is connected to the bogie assembly.
In some embodiments, the bogie assembly is pivotably connected to the frame via a resilient body structured and configured for permitting pivotal motion of the bogie assembly relative to the frame upon deformation of the resilient body.
In some embodiments, the pivotal motion of the bogie assembly relative to the frame is about a transversal axis.
In some embodiments, the pivotal motion of the bogie assembly relative to the frame is about a longitudinal axis.
In some embodiments, at least one of the leading, intermediate and trailing support wheel assemblies is rotationally connected to the bogie assembly via a resilient pivot structured and configured for permitting pivotal motion of at least one of the leading, intermediate and trailing support wheel assemblies relative to the bogie assembly about a longitudinal axis.
In some embodiments, an angular range of the pivotal motion of the at least one of the leading, intermediate and trailing support wheel assemblies relative to the bogie assembly is at least 3 degrees.
In some embodiments, the track system is operatively connected to an axle of the vehicle. In some embodiments, the axle is a drive axle.
In some embodiments, the track system is steerable by a steering system of the vehicle defining a steering axis to change an orientation of the track system relative to the vehicle.
In some embodiments, the intermediate axis extends behind a projection of the steering axis.
In some embodiments, the endless track is an elastomeric track.
In some embodiments, the track system is configured for operative connection to a vehicle being one of an ATV or a UTV.
In another aspect of the present technology, there is provided a vehicle having the track system connector according to the above aspect or according to the above aspect and one or more of the above embodiments.
In some embodiments, the vehicle is an ATV or an UTV.
Embodiments of the present technology each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein.
Additional and/or alternative features, aspects, and advantages of embodiments of the present technology will become apparent from the following description, the accompanying drawings, and the appended claims.
For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:
The description of the present technology, which relates to various embodiments of a track system having a bogie assembly and a vehicle equipped with the track system, is intended to be a description of illustrative examples of the present technology.
It is to be expressly understood that the various embodiments of the track system and of the vehicle are merely embodiments of the present technology. Thus, the description thereof that follows is intended to be only a description of illustrative examples of the present technology. This description is not intended to define the scope or set forth the bounds of the present technology. In some cases, what are believed to be helpful examples of modifications or alternatives to apparatus may also be set forth below. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and, as a person skilled in the art would understand, other modifications are likely possible. Further, where this has not been done (i.e. where no examples of modifications have been set forth), it should not be interpreted that no modifications are possible and/or that what is described is the sole manner of implementing or embodying that element of the present technology. As a person skilled in the art would understand, this is likely not the case. In addition, it is to be understood that the apparatus may provide in certain aspects a simple embodiment of the present technology, and that where such is the case it has been presented in this manner as an aid to understanding. As persons skilled in the art would understand, various embodiments of the present technology may be of a greater complexity than what is described herein.
The present technology will be described with reference to an off-road vehicle 10. The off-road vehicle 10, as presented herein, is referred to as a vehicle designed for carrying or transporting something or someone by traveling on different types of grounds, including hard and flat level surfaces, soft surfaces, uneven surfaces, un-prepared surfaces, slippery surfaces, and/or irregular surfaces. It is understood that the off-road vehicle 10 can be different type of vehicles, such as but without being limited to motorized vehicles (agricultural vehicles, industrial vehicles, recreational vehicles, utilitary vehicles, military vehicles, robotic vehicles, exploration vehicles, etc.) or non-motorized or towed vehicles (trailers, carts, etc.) having at least one axle to which a track system is connectable.
Referring to
As discussed below, in various embodiments, the track systems 161-164 may have various features to enhance their traction and/or other aspects of their use and/or performance, such as, for example, features to ameliorate their maneuverability, to better adapt to ground, and/or to improve overall ride quality.
The powertrain 12 is configured to generate motive power and transmit said motive power to the track systems 161, 162, 163, 164 to drive the ATV 10. It is contemplated that in some embodiments, the powertrain 12 could only transmit motive power to some of the track systems 161, 162, 163, 164 (i.e. only to the rear track systems 163, 164). The steering system 17 is configured to enable an operator of the ATV 10 to steer the ATV 10. To this end, the steering system 17 includes a handlebar 21 that is operable by the operator to direct the ATV 10 along a desired course. In other embodiments, the handlebar 21 could be replaced by another steering device such as, for example, a steering wheel. In response to the handlebar 21 being steered, the track systems 161-162 pivot about the corresponding steering axis 20, thereby changing the orientation of the track systems 161-162 relative to the vehicle chassis 11, thus causing the ATV 10 to turn in given direction.
Referring to
The track systems 161-164 engage the ground to provide traction and floatation to the ATV 10. More particularly, the front track systems 161-162 provide front traction to the ATV 10, and the rear track systems 163-164 provide rear traction to the ATV 10. Similarly, the front track systems 161-162 provide front floatation to the ATV 10 while the rear track systems 163-164 provide rear floatation to the ATV 10.
With reference to
The track system 161, which defines a longitudinal center plane 30 (
The endless track 41, has a ground-engaging outer side 41o and an inner side 41i that is opposite to the ground-engaging outer side 41o. The inner side 41i is configured to be drivingly engaged with the drive wheel 42. The endless track 41 is an elastomeric track. It is contemplated that in other embodiments, the endless track 41 could be constructed of a wide variety of materials and structures including metallic components.
Referring to
The tensioner 70 is operatively connected to the front idler wheel assembly 601. The tensioner 70 maintains a tension of the endless track 41 constant notwithstanding pivotal movement of the bogie assembly 100. It is contemplated that in some embodiments, the tensioner 70 could be operatively connected to the rear idler wheel assembly 602.
As best seen in
The bogie assembly 100 has a bogie body 101 extending in front of and behind the bogie assembly axis 102. The bogie body 101 defines a leading axis 111, an intermediate axis 112, and a trailing axis 113. The leading, intermediate and trailing axes 111, 112, 113 are generally transversal to the longitudinal center plane 30. In the present embodiment, the intermediate axis 112 is coaxial with the bogie assembly axis 102. As shown in
The leading axis 111 extends in front of the intermediate axis 112, and is longitudinally spaced therefrom by a distance 110 (
The bogie body 101 has the leading, intermediate and trailing support wheel assemblies 501-503 connected thereto. The leading support wheel assembly 501 is rotationally connected to the bogie body 101 about the leading axis 111, the intermediate support wheel assembly 502 is rotationally connected to the bogie body 101 about the intermediate axis 112 and the trailing support wheel assembly 503 is rotationally to the bogie body 101 about the trailing axis 113. In the present embodiment, as mentioned above, the leading, intermediate and trailing support wheel assemblies 501-503 are disposed vertically below the front and rear idler wheel assemblies 601-602. In the present embodiment, each of the leading, intermediate, and trailing support wheel assemblies 501-503 includes two laterally spaced wheels. It is contemplated that in some embodiments, each of the leading, intermediate, and trailing support wheel assemblies 501-503 could only have a single wheel in the transversal direction of the track system 161. In some embodiments, at least two of the leading, intermediate and trailing support wheel assemblies 501-503 are substantially aligned in the transversal direction of the track system 161. In some embodiments, the leading, intermediate and trailing support wheel assemblies 501-503 are substantially aligned in a direction transversal to the track system 161.
In some embodiments, the intermediate support wheel assembly 502 could be directly rotationally connected to the lower portion 44l of the frame 44 between the front idler wheel assembly 601 and the rear idler wheel assembly 602.
As mentioned above, when the track system 161 rests on a hard and flat level surface, the front and rear idler wheel assemblies 601-602 are positioned vertically above the hard and flat level surface and the leading, intermediate and trailing support wheel assemblies 501-503. Thus, an approach angle AA is formed between the endless track 41 and the hard and flat level surface in front of the leading support wheel assembly 501 (shown in
Referring to
The track system 161 is configured such that the total ground force 214 is concentrated at the intermediate ground force 212 when the track system 16i is at rest on a hard and flat level surface. Thus, as best seen in
As mentioned above, the bogie assembly 100 is free to pivot about the bogie assembly axis 102 such that when the track system 161 is travelling on a hard and uneven surface and encounters an obstacle 80 (schematically shown in the Figures), the bogie assembly 100 acts as a rocker. As such, when one of the leading support wheel assembly 501 and the trailing support wheel assembly 503 moves in a direction (e.g. moving up), the other one of the leading support wheel assembly 501 and the trailing support wheel assembly 503 moves in an opposite direction (e.g. moving down), and vice versa. Arrows in
Referring to
Referring to
Referring now to
Referring now to
Referring now to
Then, as the track system 161 continues to move in the forward direction, the rock 80 is just ending contact with the ground-engaging outer side 41o of the endless track 41. This results in the bogie assembly 100 returning to the initial position, such that the trailing support wheel assembly 503 moves in the downwards direction. The trailing support wheel assembly 503 moving in the downwards direction causes the bogie assembly 100 to pivot counterclockwise, such that the leading support wheel assembly 501 moves in the upwards direction. Thus, eventually, the total ground force 214 is mostly distributed in the intermediate ground force 212.
As mentioned above, the magnitude of each of the leading ground force 211 and the trailing ground force 212 can vary in accordance with the distance ratio 130, with the rotational position of the bogie assembly 100 relative to the frame 44 and the tension in the endless track 41.
In another illustrative example referring to
In contrast, referring to
In some embodiments, the track system 16i is a track system steerable via the steerable system 17 of the vehicle 10 about the steering axis 20 to change the orientation of the track system 16i relative to the vehicle 10. In these cases, having a total ground force 214 concentrated at the intermediate ground force 212 (i.e. under the support wheel assembly 502) can reduce the steering effort. In these embodiments, the track system 161 can be configured such that the intermediate axis 112 may be longitudinally offset from a projection of the steering axis 20 to facilitate and/or stabilize the maneuverability of the track system 16i. For instance, in the present technology, the intermediate axis 112 is behind the projection of the steering axis 20, as shown on
Referring to
The resilient body 250 is formed of resilient material. The resilient body 250 can be molded and cured directly between the bogie assembly 200 and the frame 44, or configured to be connected to the frame 44 at one end and to the bogie assembly 200 at another end. The resilient body 250 can be connected permanently (e.g. overmolding, bonding, etc.) or removably (e.g. fastening, clamping, snaping, etc.). In some cases, the pivotal motion of the bogie assembly 100 relative to the frame 44 is guided (e.g. by stoppers, sidewalls, pin-slot, etc.) in such way that the pivotal motion of the bogie assembly 100 is about a transversal axis (e.g. the bogie assembly axis 102, the intermediate axis 112, or another axis) for allowing pitch-about oscillations. In such embodiments, the bogie assembly 100 has a limited range of roll-about motion, which may further assist in increasing the durability of the track system 16i under certain conditions.
The bogie assembly 200 and the resilient body 250 are further configured such that, in part due to the resilient nature of the resilient body 250, the bogie assembly 200 is free to pivot about a longitudinal axis 201 relative to the frame 44. Thus, the bogie assembly 200 is free to pivot three degrees clockwise and three degrees counterclockwise in the roll motion about the longitudinal axis 201. It is contemplated that in other embodiments, the bogie assembly 200 could have a range of motion of more or less than three degrees in either direction. In some embodiments, the bogie assembly 200 could be guided using suitable components (e.g. by stoppers, sidewalls, pin-slot, etc.). In yet other embodiments, the bogie assembly 200 and the resilient body 250 could be configured to not pivot about the longitudinal axis 201. In yet other embodiments, the bogie assembly 100 could have a limited range of motion in the pitch, which could increase the durability of the track system 161.
Referring to
Referring to
The slide member 401 has an elongated body 402 and is made from a wear resistant material that has a relatively low coefficient of friction with the inner side 41i of the endless track 41, such as UHMW or HDPE. By default, the slide member 401 is configured and disposed in such way that the slide member 401 is not in constant contact with the inner side 41i of the endless track 41 and is aligned with the longitudinal direction of the track system 161. As shown in
In some embodiments, the slide member 401 is connected to the frame 44, the connection between the slide member 401 and the frame 44 being permanent (e.g. bonding, overmolding, etc.) or removable (e.g. fastening, clamping, etc.). In these cases, the slide member 401 can move relative to the pivoting bogie assembly 100.
In some embodiments, the slide member 401 is connected to the bogie assembly 400, the connection between the slide member 401 and the bogie assembly 100 being permanent (e.g. bonding, overmolding, etc.) or removable (e.g. fastening, clamping, etc.). In these cases, the slide member 401 is pivotal relative to the frame 44 and fixed relative to the bogie assembly 100.
It is understood that when the track system 161 travels on soft surfaces (e.g. snow, mud, sand, etc.) the distribution of the total ground force 214 may differ from what has been described herein, at least in some circumstances. As a person skilled in the art will understand, soft surfaces or grounds vary in density, bearing capacity, compactness, etc. and have tendency to reshape when the track system 161 travels over them due to the load applied to them. Floatation becomes a determinant factor for the overall performances of the track system 161, combined with traction. The present technology is optimized to meet both requirements, i.e. a quasi-punctual ground force applied on a hard surface mimicking a wheel in order to reduce friction and thus reduce the steering effort required for changing the orientation of the track system 161 relative to the ATV 10, and a good floatation on a soft surface due to the layout of the track system 161 that allows a contact surface with the ground that is large enough to ensure a good distribution of the ground force while being lightweight. Furthermore, the present technology, in part due to the pivotal motion of the bogie assemblies 100, 200, 300, 400 can aid the track system 161 to better conform to the asperities of the ground surface, enhancing the traction, the ride quality and the maneuverability of the track system.
Modifications and improvements to the above-described embodiments of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present technology is therefore intended to be limited solely by the scope of the appended claims.
This application claims the benefit of and priority to U.S. provisional patent application No. 63/195,863, filed on Jun. 2, 2021; the content of which is herein incorporated in entirety by reference.
Number | Date | Country | |
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63195863 | Jun 2021 | US |