CN1418161A - Off-highway off-road dump truck - Google Patents

Abstract

The invention discloses an automatic unloading truck that usually travels off-road or in the field. The truck has a frame with a front end and a rear end. The rear end of the frame is supported by at least two wheels connected to the partial frame. The truck also has a front strut support connected to the frame near the front end. The truck has at least first and second strut modules connected to the front strut support. The first and second strut modules each have a separate steering mechanism and at least one wheel and tire assembly. Each of the first and second strut assemblies may also have one or more electric motors that may drive the respective wheel and tire assemblies independently of the other wheel and tire assemblies of the strut module and the other strut modules.

Description

Off-road or off-road dump truck

related application

This invention is related to: U.S. Provisional Application Serial No. 60/177,147 filed January 20, 2000; U.S. Patent Application Serial No. _____ filed January 10, 2001; U.S. Patent Application Serial No. filed January 11, 2001 _____.

technical field

The present invention generally relates to an automatic unloading truck, in particular to a fixed frame type automatic unloading truck.

technical background

As technology matures, it becomes even more important to apply it in the most efficient way possible. About half a century ago, components available for off-road trucks had better reliability and more performance. By using these components in an optimized structure, off-road trucks that are considered to be the future are constructed. Specifically, instead of having multiple engines, transmissions, axles and tires for larger trucks, the number of engines and transmissions is reduced to one, axles to two and tires to six. Importantly, oil suspension systems were introduced at that time. These changes resulted in a more compact truck with a shorter track and lighter weight, yet greater strength and improved maneuverability and drivability. Today, the industry still considers such a structure ideal both now and in the foreseeable future.

Traditionally, fixed frame trucks use mechanical drive members requiring the engine to be mechanically coupled to a transmission, the transmission is mechanically coupled to a differential within the rear axle, and the differential is mechanically coupled to a planetary transmission that is connected to the rear The rim is mechanically connected to the tire. The rear tires in turn provide traction on the ground to move the truck. In practice, this method is used in all on-road passenger cars and trucks, and in most off-road trucks up to about 200 tons. Currently, the capacity of off-road trucks has been increased to 360 tons. About half of those trucks use mechanical drive components. The remaining half uses electrical drive components.

In the last few years, large trucks (300 tons and above) have switched from direct current (DC) motors to a new technology that efficiently controls the speed and torque of alternating current (AC) motors. Mechanical drive systems can provide power over a wide speed range. DC systems can only provide power over a narrow speed range. AC systems provide power over a greater speed range than DC systems, but within a narrower range than mechanical drive systems can provide. However, AC systems are a better choice due to their superior reliability and simplicity.

Electric drive vehicles currently offered in the industry have the same location for the engine and alternator as mechanical drive trucks have for the engine and transmission. Typically, two electric motors are placed at the center of the rear axle instead of a mechanically driven differential, and power is transmitted directly into the rear axle through a gear reducer. These prior art trucks still use the traditional two axle, six tire construction having a single rear axle with two sets of dual tires for driving the truck. The two front wheels are not driven, but only serve to control the direction of the truck. They do not steer flexibly for a number of reasons, such as keeping the overall width of the frame and wheels apart to a minimum, and in doing so, the frame supporting the engine and front suspension limits steering performance. After nearly fifty years of refinement, this two-axle, six-tyre truck structure is still practically limited in size and efficiency.

Thirty years ago, an oil hydraulic strut was developed for off-road trucks that supported two tires ( one on each side of the strut). Among the many significant advantages of this construction is the fact that the tires are separate. The dual tires on virtually all rear axles of this conventional construction are spaced very closely together. The heat generated by such large, closely spaced tires is severe. The radiated heat is transferred from one tire to the other, thus limiting the performance of the tires and thus the performance of the truck. With the tires on both sides of the struts, the distance between the tires is about six times that of the traditional double tire structure. This extra spacing effectively eliminates the problem of radiant heat.

In the past, there have been two types of trucks with a common oscillating spindle. A spindle is located on the front, non-drive, steered axle with a strut between the tires. The other main shaft is on the rear, non-steering, drive axle with an electric motor between the tires that drives the tires through a differential planetary gear set. In theory, oscillating the spindle can equalize the load on both tires. In practice, however, this is only the case when the tires are of equal diameter and are driven on flat roads. Both of these prior art trucks require the pivot point of the swing to be right on the road. On uneven pavement, a taller pair of tires will obviously shift up. However, as the lower tire moves in, the contact point of the taller tire must also move out of the centerline of the strut, a movement that shifts weight onto the lower tire.

When turning, side or transverse forces are generated. Since the pivot point is just above the ground, these side forces will shift the extra weight onto the outside tire. These lateral forces increase or decrease the load on the tire. The end result would be to apply more loads from both sources to the lower tire, and to apply lateral or transverse loads to both tires.

When the truck is driving on fairly flat ground or roads and the turns are not very fast, there are generally no problems, however, when the ground becomes extremely uneven and/or when the truck is turning quickly around corners, there are two The desired situation exists. First, due to the structure between the tires of all these vehicles, it is necessary to limit the oscillation of the main shaft. When the main shaft is at its swing limit, a series of structural problems occur in all components. Larger vertical loads are applied to the lower tire, while larger lateral loads are applied to both tires. Side loads can cause significant premature wear hazards to drive components, bearings and structures, etc. Second, when one tire blows out, there are very severe dynamic forces on all structures and the remaining tire.

For non-oscillating spindles, an increase in load between the tires will only occur when an uneven ground causes one tire to steer more than the other. When a tire blows out, nothing serious can happen to a non-oscillating spindle. The struts are generally of such a design that a full load can easily be handled on one tire. If a wheel bearing is designed for 500,000 miles, it will last 50,000 miles in this case. Ideally, failed tires could be replaced within that time frame. On extremely uneven surfaces, the tire load between the struts with non-oscillating spindles is only greater than that generated between tires with struts with dual tires driven by a conventional truck on the same uneven surface. The tire load is slightly larger.

Also, for non-oscillating spindles, the tires can be placed close to the struts. For an oscillating spindle, the tire must be spaced far enough from the strut to allow oscillation. This additional distance exacerbates the forces on the tire and when the oscillating spindle hits the oscillating limiting structure. In addition, the stable base of the non-oscillating spindle is on the outside tire. The stable base of the oscillating spindle is at the pivot point between the tires. While this is much better than having the stabilizing base on the rear axle in a normal truck, it's still not as good as being on the front or non-oscillating main shaft on a normal truck. As such, there is little benefit to oscillating the spindle except for some serious functional issues and higher manufacturing and operating costs.

In recent years, people have found a need for trucks that can operate on unmodified roads or in the wild. Thus, an all-terrain articulated all wheel drive truck was developed that is articulated slightly forward of the center of the truck. Drive the rear axle through the driveline at the joint. Such trucks have become a standard in the construction industry, with all their wheels driven on loose off-road conditions. Also, as all farmers know, less fuel is used when the front wheels of the tractor are driven. When actuated, they apply pull, and when not actuated, they apply push. However, the industry generally limits the capacity of these units to only 40 tons. That's only one-ninth the volume of a typical larger two-axle truck. Truck manufacturers in Russia and the United States saw the need to offer high-capacity all-wheel-drive trucks. They both developed a large version of this articulated truck, but neither made an industrial impact. Production of these trucks was discontinued due to their lack of steerability, excess weight, instability, and high cost to manufacture and operate. Furthermore, the construction of these articulated trucks was fundamentally wrong in itself. When a vehicle turns, weight shifts forward and sideways as the vehicle turns. To counteract these forces, the front outside tire should either stay in place or effectively move to the outside of the bend. With these articulated trucks, the front outboard tires swing inwards and thus require a counter motion, thereby reducing their stability.

These small all-terrain articulated trucks are generally considered to have a lighter load capacity than standard frame-on-frame off-road trucks. Surprisingly, due to their light construction, they have a very poor payload to net weight ratio (P/W), which ranges from 1.05/1 to 1.2/1.

An empty truck must travel in two directions between the loading point and the unloading point, while the payload travels in one direction. To estimate the cost of moving the truck relative to the entire payload, a factor of 2 (W/P) can be used, described in more detail below.

For every $1.00 spent moving the payload, an articulated truck with a P/W ratio of 1.12 requires $1.78 to move the truck. Most designs of current off-road trucks have payload to weight ratios between 1.4 and 1.6. With a P/W of 1.5, for every dollar spent moving the payload, $1.33 is required to move the truck.

Conventional fixed-frame trucks use limited-stroke, non-compensating suspension systems that require tires and structural members to absorb applied dynamic and torsional stresses. This requires heavy structural members which, due to their construction, tend to have areas of high stress concentration.

In addition, there are other problems associated with these existing trucks. Common trucks have dual rear tires, these tires are mounted on the same hub, the hub requires both tires to turn at the same speed, since each tire is at a different distance from the point around which the truck turns, the same speed when turned causes double Tire rubbing. This requires that the individual tires rotate at different rates, which cannot be done since the tires are mounted on the same hub. Since the double tires rotate on the same hub, they must also be dimensionally matched with high precision. Otherwise, abnormal wear will occur on the smaller tires because the smaller tires have a smaller radius and must turn faster. Obviously, there is less load on smaller tires. A tire with a heavier load will not slide, so a smaller tire with a lesser load must slide and will wear out. As smaller tires get smaller over time, the tires also wear faster and faster. Additionally, with dual tires, the outer tire and rim must be removed in order to replace or access the inner tire.

Description of drawings

Fig. 1 is a lower front isometric view of a dump truck constructed according to the teachings of the present invention.

Figure 2A is an upper front isometric view of the dump truck of Figure 1 with the body up and the tires in a straight forward orientation.

Figure 2B is an upper front isometric view of the dump truck of Figure 1 with the body up and the tires in a position of maximum rotation.

Figure 3 is similar to Figure 2, but in Figure 3 the tires are parallel at 90 degrees and the dumping body is dumped to one side relative to the direction of movement of the truck.

Figure 4 is a rear view of the truck of Figure 1 .

Figure 5 is a top view of the truck of Figure 1 with only the dumping body shown in dashed lines.

6 is a side view, partially in section, of a strut module of the truck of FIG. 1 .

Figure 7 is a rear isometric view of a strut module of the truck shown in Figure 1 with one wheel removed.

Figure 8A is a front upper axial view of the strut module with a motor and brake cooling air inlet, motor control, motor control cooling fan, fan motor and brake grille.

FIG. 8B is an enlarged view of a portion taken from the circular portion of FIG. 8A.

Figure 9 is a top cross-sectional view through the center of the lower strut, motor and spindle showing the air flow path and components of the module assembly.

Figure 10 shows the routing of all the lines from the main suspension part of the truck to the location of the movable and turnable part of the truck.

Figure 10A shows all the power lines in Figure 10 with all other structures removed.

FIG. 10B shows the wiring for the ground wire, temperature sensor, and traction motor speed indicator shown in FIG. 9 and the wiring for the fan and pump drive motor control wires shown in FIG. 7 .

FIG. 10C shows the routing of the hydraulic lines for the brake and hydraulic motor of FIG. 8 .

Figure 10D shows the routing positions of the various lines when a strut module is oriented in standard straight forward.

Figure 10E shows the routing positions of the various pipelines when the strut module is turned to a larger corner.

11A to 11F are schematic diagrams of possible steering modes for the truck of FIG. 1 .

12 is an upper front isometric view of another embodiment of a truck constructed in accordance with the present disclosure in which only the front wheels are steerable.

Figures 13A and 13B are top views of the belt tipping body within the phantom line of the truck shown in Figure 12 and with a modified front wheel steering arrangement.

Figures 14A and 14B are top views of the truck shown in Figures 13A and 13B with another modified front wheel steering configuration.

Detailed ways

Hereinafter, embodiments of a dump truck according to the present disclosure will be illustrated and described. Although the disclosed dump trucks may be used in on-road applications, they are particularly suitable for off-road applications, and may even be suitable for off-road applications. The trucks disclosed herein increase productivity, reduce costs, and are capable of cost-effective operation under the most adverse conditions. This makes it more economical to develop a mine, not least thanks to reduced transportation costs. At least some of the tires are mounted separately, avoiding friction as the tires turn. Since the tires can be mounted and driven individually, these tires do not need to be precisely matched in size. The truck's steering capability allows access to the inner or outer tires without removing the other tires in the set. As the truck disclosed herein allows, by turning the tires over 90 degrees, all of the tires can be easily accessed when turned properly, and can be replaced individually with or without removing the rim. This unique or novel truck structure can solve the above-mentioned problems existing in conventional trucks, and this structure also has many other features and advantages, which will be apparent from the following description.

Figures 1-5, 8A, 8B and 11A-11F illustrate one embodiment of a truck constructed in accordance with the present disclosure. Figures 12, 13A, 13B, 14A and 14B show another example of a truck. Figures 6, 7, 9 and 10-10F illustrate an embodiment of a strut module in accordance with the present disclosure that is particularly useful on the trucks described herein.

Referring now to the drawings, Figures 1-5 generally illustrate a truck 20 constructed in accordance with the present disclosure. The truck 20 has a frame 22, the middle portion 24 of which forms the longitudinal axis "A" of the truck. The frame 22 also has a front transverse portion 26 and a rear transverse portion 28 which are connected to and arranged substantially perpendicular to the central portion, whereby the frame 22 has an I-shaped configuration in plan view. Each transverse section forms a strut support for the truck 20, as will be described in more detail below.

The frame 22 is supported above the ground, in this embodiment on several wheel and tire assemblies 30 . The wheel and tire assemblies are mounted on front and rear strut modules 32F and 32R respectively (abbreviated as 32 if the forward or rear facing modules are not specifically identified below), which will be further described below. Modules 32F and 32R are in turn mounted against opposite ends of front and rear frame sections 26 and 28, respectively. In this embodiment, each of the four strut modules 32 carries a pair of wheel and tire assemblies 30, so there are eight in total. Each of the eight wheel and tire assemblies 30 has a tire 34 mounted on a wheel rim 36 for rotation about a portion of a corresponding strut module 32 .

The truck 20 also has a dump body 38 pivotally mounted on top of the frame 22 . When the pouring body 38 is in a lowered position ( FIG. 1 ), it is suitable for loading goods and a front end 40 of the pouring body 38 can be raised to dump the goods. The rear end 42 of the pouring body 38 has a pair of pivot structures 44 depending from a bottom surface 46 thereof. These pivot structures 44 are connected to pivot structures 45 depending from the rear transverse frame portions 28 at equidistantly opposite ends of the frame middle portion 24 .

To unload cargo from the dump body 38, in one embodiment the truck 20 has a single extendable hydraulic cylinder 48 that is pivotable at a ten head 50 along a central axis "A". The ground is connected to the front of the frame 22. In this embodiment, the deca header 50 is centrally carried on the forward facing surface 52 of the front transverse frame portion 26 . Ten head 50 is positioned forward of the end of frame midsection 24 and forward of front wheel and tire assembly 30 and outside of the steering or rotational envelope of tire 34 created by rotation of the strut modules. The dump cylinder 48 has a second end pivotally connected to the bottom side or surface 46 of the dump body 38 near the front end 40 of the dump body 38 . When the dump cylinder 48 extends, as shown in FIG. 2 , the dump cylinder 48 raises the front end of the dump body 38 . Certain benefits are realized by this arrangement, which will be described in more detail when the operation of the various features and features of truck 20 is described.

The pouring body 38 rests on the top surfaces 56 and 58 of the transverse frame portions 26 and 28, respectively, when the pouring body 38 is being loaded and conveyed. This allows the pouring body 38 and frame 22 to work as a unit, reinforcing and supporting each other. In fact, there are no loads or bending moments on the frame portions 24 , 26 and 28 of the truck 20 imposed by the dump body 38 itself or the load or cargo within the dump body 38 .

The truck 20 also typically has a cab 60 that typically houses controls for manipulating the truck 20 . Cab 60 also typically accommodates suitable amenities (not shown) for the truck driver, such as one or more seats, windows, environmental controls, doors, audio and communication devices, and the like. The cab in this embodiment is disposed near one end of the frame 22 near the front transverse frame portion 26 and is supported by the frame 22 in a raised position. The cab 60 can be located either on one side of the truck or in the middle above the axis "A". In this embodiment, the cab 60 is positioned slightly forward of the front wheel and tire assembly 30 and below or below the front end 40 of the dump body 38 . This position increases the operator's visibility and allows the driver to see the front wheel and tire assembly 30 at all times if desired.

The intermediate portion 24 of the frame 22 interconnects the front and rear lateral portions 26 and 28 and thereby connects the front strut or suspension module 32F to the rear strut module 32R. The middle frame portion 24 in this embodiment contains one or more power modules 66, which may have a radiator 61, an engine 62, an alternator 64, one or more oil tanks (such as for holding engine oil), a or multiple hydraulic tanks 70 (eg, for brake fluid or other hydraulic actuation system fluid) and other auxiliary truck components.

It is important that the load be unloaded as quickly as possible to ensure maximum productivity of the truck 20 . The high pressure oil that tilts the dump body 38 enters through the end 47 of the rod of the multi-stage dump cylinder 48 . The end 47 of the rod is attached near the front of the body 40 . In order to reduce the size of the hydraulic pump and the size and length of the piping, and in order to facilitate the rapid lifting of the dump body 38 and its cargo, a dump cylinder 48 is installed on the bottom side 46 of the dump body 38 very close to the dump hydraulic cylinder 48. or a plurality of hydraulic accumulators 72 . The accumulator 72 in this embodiment is connected by two larger dump valves 74 to ensure proper flow to the end of the rod of the dump cylinder 48 near the forward end of the middle section 24 of the frame 22 . An additional hydraulic tank 76 is located in close proximity to the dump valve 74 so as to quickly receive oil from the dump cylinder 48 when the dump body 38 is lowered to the frame 22 .

A suitable location for an additional accumulator 72 is within the middle portion 24 of the frame 22 in order to assist in the continuous adjustment of the drive dump cylinder 48 , the steering cylinder 132 , and the strut 11 . A high pressure gas hydraulic cylinder 78 , where the gas is typically nitrogen, may be located in the middle section 24 to store energy to drive all the accumulators of the truck 20 . Alternatively, these gas hydraulic cylinders 78 and accumulators 72 can be mounted in any location on the truck as desired. As the load on the truck increases, the gas in chambers 98 and 99 in strut 100 compresses (see FIG. 6 and described below), and oil from accumulator 72 flows into chamber 97, which The 97 maintains a constant truck height both loaded and unloaded.

The structure and configuration of the I-frame 22 and dump body 38 provide for a reduced dry weight of the truck 22 as compared to known truck structures. The construction of the frame 22 and dump body 38 also yields the added benefit of providing two additional tires 34 on each side of the truck's front suspension module 32F compared to conventional truck designs with only one tire per side. Space. The structure of the strut module 32, which will be described in more detail below, also allows two additional tires 34 and rims 36 to be mounted on the front end of the truck with only a minimal increase in cost and weight. The additional cost and weight is simply due to the additional wheel and tire assembly 30 . Due to the available space created by this configuration of the truck 20 , the second power module 66 can also be easily attached to the frame 22 , which greatly increases the productivity of the truck 20 . The close proximity of the individual tires to the struts is important to help reduce the overall width of the truck. The rotational envelope of the tires on the struts can be accommodated with sufficient space under and between the frame members. However, the rotational envelope surface of one strut must move away from the rotational envelope surface of an adjacent strut, thereby allowing a larger strut rotational angle.

The structure of the frame 22 and the dumping body 38 can also make the track 50% longer than that of a normal truck. As a result of the substantial extension of the track, weight offsets between the axles can be minimized when the truck 20 is in operation. Smaller weight offsets reduce static and dynamic loads on the frame 22 and pourer structure 38 . The smaller weight offset also reduces the load on the front tires 34 when cornering. An important feature is that the truck 20 has four tires 34 at the front, two on each side, to absorb lateral forces and forward weight excursions when the vehicle turns.

Referring now to FIG. 6, a partial cross-section of the strut unit 32 is generally shown, with the outer wheel and tire assembly 30 removed. However, each strut module 32 includes two tires 34 which, in this embodiment, are mounted on respective rims 36 carried on opposite sides of the strut 100 . In this embodiment, the two main shafts 142 are fixed to the pole part 110 of the strut and cannot swing.

Each module 32 generally has a hydraulic strut assembly 100 connected to a respective end of one of the transverse frame sections 26 or 28 above the tire 34 . A strut assembly 100 hangs from each of the four corners of the truck 20 . Each strut assembly 100 has a fixed strut housing 102 that is fixed to and depends from the respective frame portion 26 or 28 . Each strut housing 102 forms a strut axis S, which in this embodiment is shown substantially vertically when in the normal driving position. A steerer tube 104 in this embodiment is disposed coaxially with each strut housing 102 and is received thereon, the steerer tube being adapted to rotate relative to each housing 102 . A steering link 106 is fixed near the upper end of each steering tube 104 and forms a plane substantially perpendicular to the axis S of the strut 100 . As best shown in FIG. 5 , each steering link 106 forms a pair of substantially opposing steering arms 108 and 109 . The steering arms 108 and 109 can be manipulated as follows to operate each strut module 32 individually.

Each strut assembly 100 also has a hydraulic cylinder rod 110 that is telescopically received within the housing 102 and is slidable relative to the housing 102 . When in the normal driving position, the hydraulic cylinder rod 110 is positioned near the midpoint of its range of vertical movement relative to the housing 102 so that it can extend out or out of the housing as required when driving on varying road surfaces. retracted into the housing. A spindle housing 112 is fixed to the bottom end of the hydraulic cylinder rod portion 110, and it has a cylindrical wall portion 114 which surrounds the outer surface of the steering tube 104 at the lower end. The spindle housing 112 is movable vertically with the cylinder rod 110 and relative to the steerer tube 104 . The hydraulic cylinder rod 110 and housing 102 may operate as a conventional hydraulic strut 100 to cushion loads. In this way, the spindle housing 112 can move vertically relative to the corresponding frame portion 26 or 28 for shock absorption.

A scissor link 120 has a first link arm 122 pivotally connected at a first pivot joint 124 by a The first bracket 125 is formed. The scissor linkage 120 also has a second linkage arm 126 that is pivotally connected to a second pivot joint 128 by a second bracket secured to the spindle housing 112. frame 129 is formed. The outer ends of the first link arm 122 and the second link arm 126 are connected to each other at a third pivot joint 130 . Pivot joints 124 , 128 , and 130 of scissor linkage 120 allow spindle housing 112 to move freely along strut axis S relative to steerer tube 104 and strut housing 102 . However, each member of the scissor linkage 130 is robustly designed to resist relative rotation between the steerer tube 104 and the spindle housing 112 . Thus, when the steering tube 104 is rotated about the strut axis S by movement of the steering linkage 106 as described below, the spindle housing is also rotated, thereby rotating the wheel and tire assembly 30 .

2 and 5, each strut module 32 is independently operated by a pair of extendable hydraulic steering cylinders 132 and 133, and one end of each steering cylinder is connected to the steering arms 108 and 109 of the steering linkage 106. Corresponding ones of them are pivotally connected together. The opposite ends of the steering cylinders 132 and 133 are pivotally connected to the bracket portion of the frame 22 . Each steering cylinder 132 and 133 has an extendable rod 134 controlled by a steering cylinder control valve 131 . If desired, pressure indicators on each control valve 131 can be used by a computer (not shown) to coordinate steering cylinder pressure with wheel motor torque.

Proper extension and retraction of the steering cylinders 132 and 133 of a particular strut module 32 will cause the corresponding steerer tube 104 to rotate about the strut housing 102 relative to the axis S, thereby causing the spindle housing 112 to rotate, and thereby the The tire assembly 30 of the wheel rotates. In one embodiment, the tires 34 and wheels 26 of a particular module 32 are turned in excess of 90 degrees in each direction, such as about 120 degrees or more, from the nominal position shown in FIG. 3 .

Referring to FIG. 9 , each wheel and tire assembly 30 may be individually driven by a separate electric motor 140 mounted inside a spindle 142 supporting each rim 36 . Each motor 140 is preferably an individually controlled AC motor 140 . The electric motor 140, which gets its power from high speeds, must be combined with a speed reducer 139 to obtain the high torque to create the drawbar needed to propel such trucks 20 through loose ground and up steep inclines. A truck 20 with high torque and the ability to drive all wheels independently is particularly useful in the mining and construction industries. As shown in Figure 9, each main shaft 412 inside has a motor 142, and is supported with two bearings 136, and these two bearings are supported with a wheel hub 144 again, and this wheel hub supports speed reducer 139, a rim 36 and One of a plurality of tires 34 is preferably supported. Each spindle housing 112 has two spindles 142, one on each side of which are connected to an intermediate structure containing a hole, preferably tapered, which receives the strut shaft 110. Each motor 140 drives only one of the two wheel and tire assemblies 30 of each strut module 32, so each tire 34 can be driven individually if desired. The main shaft 42 and the hub 44 each support a portion of a wheel brake 138 which will limit the relative movement of the hub and main shaft when the wheel brake 138 is actuated.

Each strut module 32 also has an air cooling system for the AC drive motor utilizing air circulated through the spindle housing 112 and the spindle 142 . An example of a cooling system for each strut module 32 is shown in FIGS. 7-9 and will be briefly described below. Included within the module 32 is an air inlet 145 disposed between a respective pair of tires 34 and preferably flush with the top surfaces of the tires 34 . The air inlet duct 146 contains a motor 147 which drives a fan 148 which pushes cooling air through the air cleaner 149 into the spindle housing 112 and into the air inlet 150 demarcated by the plate 152. An inlet air cavity 151, the plate 152 separates the inlet air from the outlet air, wherein the cleaner 149 can be arranged before the fan (upstream) or after the fan (downstream). Air then enters the motor 140 through holes 153 in the non-drive end of the motor 140 , passes through the stator through holes 154 and through the rotor through holes 155 . Air exits the motor 140 through holes in the motor housing 160 . The air then returns outside the motor 140 through a gap 157 formed by the inner diameter of the main shaft 142 and the outer diameter of the motor 140 . The air then enters the outlet air cavity through a plate 152 that separates incoming air from outgoing air. The air then exits the spindle housing through holes 159 .

In one example, air exiting aperture 159 after cooling motor 140 may pass through an exhaust duct 168 . One end of the exhaust pipe 168 is connected to the outlet opening 159, while the opposite end forms an exhaust opening 170, which is positioned between the corresponding tires 34 of the strut module 32, and is preferably also connected to the tire 34. The top surface is flush. Air will flow out of outlet opening 159 through exhaust duct 168 and exit exhaust outlet 170 . The location of the outlet 170 prevents the hotter exhaust gases from heating the inner surface of the tire 34 .

In another example, exhaust pipe 168 may actually be an oil cooler for wet disc brake system 138 . Since a large amount of air must be used to keep the motor 240 cold, the air leaving the motor 140 will be much cooler than the hot cooling oil leaving the brake 138 . Air can be circulated outside the pipes 165 which carry the oil from the brakes to the pump 167 and back to the brakes 138 through the exhaust pipe 168 oil cooler, cooling the oil and brakes 138 as required. The pump 167 is driven by an electric motor 166 which may be powered by high pressure oil from the accumulator 72 which may be present on the truck. The inlet fan motor 147 of the air inlet duct 146 may also receive power from the same accumulator line 190 as shown in Figure 10D. In summary, the disclosed strut structure allows the fan motor 147 and fan to circulate cooling air to the traction motor 140 and oil cooled disc brakes 138 .

In an example, the inlet opening 150 of the inlet air tube 146 may be fixed in front of the spindle housing 112 . The outlet opening 159 of the exhaust pipe 168 may be secured behind the spindle housing 112 . The exhaust pipe 168 may pass through the upper scissor linkage bracket 125 which is fixed to the steerer tube 104 and is free to move up and down with the spindle housing 112 independently of the steerer tube 104 . As shown in FIG. 10 , the various hydraulic lines 172 for the fan motor 147 and the hydraulic lines for the parking brake 192 and service brake 194 are routed outside the scissor linkage 120 .

Thus, each strut module 32 includes strut 100, various steering components, spindle housing 11 and spindle, wheel drive motor 140, speed reducer 139, two brakes 138 and cooling systems for the motor and brakes. Each strut module 32 also includes two hubs 144 , two rims 36 and two tires 34 . Each strut module 32 also includes an airflow cooling system, hydraulic and electrical power cables, hydraulic lines for the brakes, and an electric motor that drives a cooling fan and a wet disc brake cooling oil pump. The structure of the strut modules 32 and the structure of the frame 22 of the truck 20 yields a number of advantages and benefits not found in conventional trucks of any size.

In one example, the steering link 106 and the two steering arms 108 and 109 are secured to the steering tube 104 at the highest point of the tire 34 when the strut 100 is retracted. When each of the steering hydraulic cylinders 132 and 133 is properly extended and has a suitable stroke length, a steering angle much greater than 90° can be achieved. In operation, each pair of hydraulic steering cylinders 132 and 133 can turn the corresponding strut module 32 well in excess of 120 degrees in each direction, for example to achieve a variety of different truck positions as shown in Figures 2 and 11A-11F. rotation graphics. Except when the vehicle is moving in a straight line, the wheels always turn about a given common center point.

2 and 11E, by positioning the tires 34 of each strut module 32 as required according to the length and width of the track of the truck 20, the truck 20 can turn about its center point while requiring only the turning area of a conventional truck. or 45% or less than half of the radius. As shown in Figures 11A-11C, the tires 34 can also be rotated to any position while remaining parallel to each other. In this way, the truck 20 can be driven in a straight line, while the dump body 38 and frame 22 can be oriented at any practical angle relative to the longitudinal axis A of the truck. Furthermore, as shown in FIGS. 11D and 11F , any two strut modules 32 can be steered independently of the other two strut modules 32 and can be steered independently of each other relative to either side or end of the truck 20 , not just as normal. Operate from the front end like a truck. There are many benefits to be gained from this steering flexibility. In addition, because each tire 34 on each strut module 32 is independently driven by its own electric motor 140, two tires on a module 32 can be driven at slightly different speeds, thereby eliminating tire scrubbing while turning. .

The truck 20 effectively need not be longer and wider than a normal truck, but can carry twice as much load, and its net weight is only slightly heavier than a normal truck. In order to be able to transport efficiently, ordinary off-road trucks must drive on relatively good, smooth surfaces, such as roads in repaired mines. The truck 20 can be efficiently transported over less-than-ideal surfaces, and because of its all wheel drive features, it can climb steeper grades. These factors greatly reduce the cost of transporting materials and can also significantly reduce the cost of operating the entire mine.

In one embodiment, the steering cylinders 132 and 133 may include a linear displacement sensor to determine the axial position of each extended steering cylinder rod 134 to further determine the angle of the axis of the tire 32 . An on-board computer (not shown) of the truck 20 can track this angle of each module 32 and send appropriate signals to the controls of other steering cylinders of other modules 32 . In this way, the rotational position about the strut axis S can be controlled. For example, as shown in Figures 11A-11C, all tires 34 are controlled to roll on parallel axles, thereby causing the truck 20 to move in a straight line. Alternatively, as shown in Figures 11D-11F, the axles can also be controlled such that all axles intersect at a common point to provide a desired fit radius.

Modules 32 can be individually and dynamically steered in order to maintain a common intersection when the truck is turning and traveling in a straight line. The point of intersection can be determined and controlled by a computer (not shown). The angle of the tires can be controlled in conjunction with a linear displacement sensor 201 (see FIG. 12 ) integrated with the steering cylinders 132 and 133 . The distance of all tires 34 from a common intersecting pivot point will be known at all times so that relative tire speeds can be controlled by individual motor controllers 179 . In this way, the tire 34 can pull flat, thereby avoiding galling of the tire when turning or moving in a linear path.

As mentioned above, in one embodiment, as shown in FIGS. 2 and 11E , the intersection point may be moved to a location equidistant between the front and rear modules 32f and 32R, respectively, and may be moved to the center of the truck 20 a little bit. In this steering configuration, the truck 20 can turn around itself. In this way, the truck 20 can turn around in a very compact space without moving back and forth. And this is impossible for ordinary trucks.

In another embodiment shown in FIGS. 11A and 11C , and as shown in FIG. 3 , the truck 20 can be arranged to dump cargo from the dump body 38 parallel to the truck axis A, or perpendicular to the axis A, as desired. A dumps the goods from the dumping body 38, if desired, the truck 20 can also dump the goods at any other angle. This can also be done in a very tight space without backing up the truck 20 . As shown in Figures 11A-C, this is done by rotating all strut modules at the same rate so that all struts 32 are held along parallel wheel axes W. The tires 34 always travel in a straight line, but the truck dump body 38 will turn relative to the direction of motion. The truck 20 does not need to back up to redirect the dump body 38 relative to the dump point. Instead, the tires 34 can remain in the direction of movement while the dumping body 38 is turned into a position for dumping goods. This feature is particularly useful when the truck 20 must be positioned in a tight space to dump into a hopper or must be positioned to dump over a pile. In summary, when at the loading shovel or at the dump point, the truck 20 can be moved directly into position and then easily driven away, thereby reducing the time required to steer the truck 20 into and out of a loading or dumping location. Therefore, the truck 20 is actually a rear-dump and side-dump truck.

Many in the mining industry recognize the need for a side dump truck. In the 1970s, a mining executive stated this phenomenon: "God must be doubting our intelligence, because we needlessly back up in mines to unload the distance used to circle the moon many times a year. ’” If he realizes that in many cases the truck must also back up to the shovel so that the backing distance is essentially doubled, then he should also multiply the above distance by two. Utilize the truck according to the disclosed content of the present invention, can dispense with the reversing distance when loading and unloading. Equally, also can avoid the required large amount of manpower when these super-large vehicles reversing. Furthermore, when at a loading shovel or dump point, the truck 20 can be moved directly into position and then easily exited, thereby reducing the time required to steer the truck into and out of loading and unloading positions.

Routing of the cables 184 and 186 and the various hydraulic lines is important for the rotation of the strut 100 when turning and moving the strut 100 up and down on uneven ground or poor road conditions. It is highly undesirable to use slip rings for electrical cables, and impractical to use swivel joints for hydraulic lines. The revealed truck addresses these thorny issues.

A closed chamber 174 is mounted in front of the front and rear transverse frame sections 26 and 28 . Each is provided above the steering cylinders 132 and 133 and the steering arms 108 and 109 . Above each enclosed chamber 174 is conveniently located a corresponding AC traction motor control box 179 . Through the rear of this closed chamber 174 the steering tube 104 of the strut module 32 is located. In this embodiment, from the motor control box 179 through the enclosed chamber 174 there are 12 power supply wires 175 , a ground wire 184 and a hose containing small sensor and control wires 182 . From the accumulator 72, four hydraulic lines 188-194 enter the chamber. One line 192 is for the parking brakes, one line 194 is for the service brakes and one is the high pressure accumulator oil line 190 to drive the fan motor 147 and the motor 166 that drives the brake pump 167 that circulates the brake cooling oil. There is also a low pressure oil line 188 for returning oil from the two electric motors 147 and 166 to the hydraulic tank. Additionally, there are two small valves 198 and 200, one for controlling the speed of the fan motor on demand and the other for controlling the speed of the brake pump motor on demand.

In this embodiment, these power cables 184 , 186 and hoses 188 - 194 are routed directly to the required components in the lower portion of the strut module 32 that do not have spring components installed. In this embodiment, the cables 184 , 186 and one end of the hoses 188 - 194 are clamped to the enclosed chamber 174 . They are practically the same length, and they are stacked triple high and held together properly so that they stay in the same vertical plane and minimize slack. They are then supported in such a way that abrasion between the lower cables 184, 186 and hoses 188-194 and the bottom surface of the enclosed chamber 174 is prevented. Three such stacks are loosely connected side by side. They are clipped onto the steerer tube 104 and they are routed around the steerer tube 104 down through the steering arm and down the outside of the steerer tube 104 and form a loop appropriately to accommodate the full stroke of the strut 100 . Scissor links 106 can assist in supporting the bundle as needed. Within the enclosed chamber 174, nine wires and hoses are laid along two loops 197A and 197B and form a loop appropriately to accommodate steering tube 104 rotation. Nine wires and hoses are laid along two loops 197A and 197B opposite each other. It is possible to stack nine or all eighteen wires and hoses vertically, but this would increase the height of the truck 20 and the center of gravity of the truck 20, so this is not advisable.

The efficiency of large haul trucks (which correlates to the cost of moving the payload) is directly proportional to the payload weight relative to the vehicle's curb weight (EVW). This refers to the ratio of payload to upper weight P/EVW. To relate this to the actual cost of moving the payload, one way is to multiply the EVW by 2, add the payload P, and divide by the payload P:

(EVW*2+P)/P where this formula is used to account for a situation where the vehicle is moving in both directions towards and from the load point, while the payload is only moving in one direction towards the dump point . This formula describes the amount of work a truck must do to complete a haul cycle. Assuming a payload of one, or P=1, the above formula becomes:

The formula (2/P/W+1)/1 can be simplified to 2/(P/W). For a P/W of 2.0, for every dollar spent moving the payload, it takes $1 to move the truck. At a P/W of 1.5, for every dollar of moving the payload, it costs $1.33 to move the truck. Most current off-road truck designs have a payload to weight ratio between 1.4 and 1.6. The disclosed trucks allow a P/W ratio of over 2.3, such that for every dollar required to move the payload, it costs less than 87 cents to move the truck.

A normal truck with two axles and a short wheel base has four tires on the bottom and only two on the front. While acceptable for this industry standard, it is not ideal due to load center of gravity (weight shifts forward when the vehicle goes downhill) and dynamics. In these conditions, the front tires can experience high static and dynamic overloads. If the tires fail under these overload conditions, it can easily lead to a loss of control of the truck. The disclosed truck 20 can have a 60% longer track than some comparable trucks and can use four tires 34 on the front axle. This structure greatly reduces the application on the front tires 34 when the truck is in these adverse conditions. Furthermore, if one tire 34 on a module 32 fails, the remaining tire 34 can maintain control of the truck 20 .

Another very important factor in the inherent value of a vehicle is its performance, which is related to the available horsepower of the moving unit material. There are two factors that can be used to compare vehicle performance and productivity. These are the horsepower (HP) per gross vehicle weight (GVW), or HP/GVW, and the horsepower to move the payload, or HPxPL/GVW, which is known as payload horsepower. With the large amount of open space under the frame 22 of the truck 20 and the space between the strut modules 32F and 32R, two of the largest common truck engines can easily be installed to substantially enhance the performance characteristics of the truck 20 . The configuration of frame 22 and strut modules 32 also provides non-parallel access to power modules 66 for maintenance and/or replacement. The disclosed truck 20 has a payload horsepower approximately 2.4 times greater than the maximum productivity conventional trucks currently on the market.

The main factors for estimating vehicle stability depend on the height of the center of gravity and the stability basis (SB), or in practice the square of the stability basis (SB ² ). In most vehicles today, the basis for stability of the front axle is at the center of the front tire. This configuration is good for stability, but bad for frame stress and front tire loading. The stability of the rear axle is the point at which the rear suspension system effectively acts on the centerline of the rear axle. On most normal trucks, the basis of stability is usually 5 times larger between the front and rear axles than on the front axle. When this result is squared, it turns out that a single front outside tire on a normal truck in a bend effectively absorbs all of the cornering lateral forces as well as the forward weight offset force due to the cornering. The dump body of this truck pivots as it unloads, the dump body is essentially held from tipping over by multiple pins on the rear of the truck, and is light due to the narrow frame. This common truck setup puts high torsional stress on the narrow frame and (during cornering) overloads the single outside front wheel to extreme degrees. The disclosed truck 20 can provide equal cornering force to the four tires on one side of the truck on the outside of the bend. The long track minimizes forward weight excursions from cornering. Minimized weight excursions can be absorbed by two tires 34 instead of one tire on normal trucks. A very important feature of the suggested truck is that in all similar operating situations the tires 34 will be under less stress, which not only reduces the cost of the tires 34, but also allows the truck 20 to travel at high speeds with a larger load work well.

When unloading, common trucks have their dump cylinders positioned somewhere between the two axles, requiring the cylinder to lift the combined weight of the dump body and load. This load is transferred directly into the frame. Therefore, the location of the hydraulic cylinders maximizes the stress on the frame. In the disclosed truck 20, the dump cylinder 48 is mounted on the frame 22 between the front strut modules 32F. Accordingly, the strut cylinder 48 is required to exert a force that is half the weight of the dump body 38 and load. The other half of this weight is supported by the pivot pin 43 at the rear of the truck 20 . The load is transferred along the truck axis A directly to the strut modules 32F rather than between the front and rear modules 32R. This configuration effectively eliminates bending stresses in the frame and reduces stresses in the dump body 38, also making the frame 22 stronger, yet lighter relative to the payload than conventional truck frames. FIG. 2 shows a number of accumulators 72 that help to greatly reduce the time required for the truck 20 to unload. The accumulator 72 is mounted in close proximity to the dump cylinder 48 to improve the flow characteristics of the oil from the accumulator 72 to the dump cylinder 48 . This structure unloads the truck 20 and resets the dumping body 38 in less than half of the unloading and reset time of a conventional truck, and dumps almost twice as much load.

All normal trucks must stop, turn and back up to a stacking point or hopper to unload the load. However, doing so is dangerous for at least two reasons. Firstly, the driver must be very careful, otherwise he will back the car onto a dump point or into an object. Second, the inertial force of the truck's weight due to braking can be applied to stop at the edge of the pile, sometimes causing the pile to collapse.

This stopping, reversing, bending, backing up and stopping again is not only taxing on the truck, but also time consuming. The traditional process also makes the card go back under the shovel for loading, and returns to a discharge point for unloading. The disclosed truck 20 completely eliminates this unproductive, unsafe and wasteful maneuver at both ends of the pull cycle.

The disclosed dump truck 20 allows for greater capacity, greater efficiency and improved maneuverability. Furthermore, all tires 34 can be driven and steered independently, allowing excellent maneuverability in poor traction conditions. The disclosed truck 20 is very strong, has a high carrying capacity, and is extremely light in its load relative to its weight, with outstanding performance characteristics in the most adverse conditions. The disclosed truck 20 provides major advancements not only in truck capacity, but in every feature required by the earth moving industry to both increase productivity and reduce the cost of transporting materials. Importantly, the disclosed trucks can thereby reduce the cost of operating a mine, construction site, and the like.

Figures 12, 13A, 13B, 14A and 14B show in more detail the simplified operating configuration to achieve the steering pattern shown in Figures 11A and 11D. For example, Figure 12 shows a truck 300 constructed in accordance with the teachings of the present invention. The disclosed truck 300 has only the front strut module 32F described above. As noted above, the front wheel and tire assemblies 30 can be individually steered through relatively large steering angles, such as 105, 110, 120 degrees or more, in each direction. However, in a preferred embodiment, the rear strut module 298R is held by fixed linkages and is non-steerable. They always remain in the straight forward orientation as shown.

One of the front and rear wheels can be driven, or both can be driven. When the front wheels are driven, in a preferred embodiment, one or more front wheel and tire assemblies 30 may be driven individually by the individual electric motors 140 described above. However, the front wheels need not all be driven. Similarly, if the rear wheels are driven, one or more rear wheels may be driven by corresponding electric motors 140 as described above, or the rear wheels may be driven in a conventional manner. In this front-wheel steered configuration, it is preferable to drive the rear wheels.

Two rear strut modules 298R can be fitted to each truck, one on each side, either at the front or rear of the truck, or four can be fitted per vehicle. Rear strut modules 298R and/or rear wheel and tire assemblies 296R may be mounted on common non-drive axles. The rear wheel and tire assembly 196R may also be mounted on a rear strut module 298R that is substantially the same as the module 32R described above, as long as they are non-steering and non-steering. Each rear wheel and tire assembly can be individually driven at different speeds by its own individual electric motor as described above, thus avoiding friction in rotation.

In addition to the other benefits gained through the aforementioned front strut module 32F, the truck 300 has what is known as an Ackermann steering trapezoidal geometry and steering gear similar to conventional vehicles and trucks. Figures 13A, 13B, 14A and 14B illustrate a truck 300 with Ackermann front wheel steering, but with an alternative steering mechanism and configuration.

Figure 13A (front wheel steer) and Figure 13B (front wheel straight) show the truck 300 with another steering configuration. In the embodiment disclosed herein, truck 300 has a frame 301 and front and rear strut modules 298F and 298R, respectively, which are similar to frame 22 and module 32 described above, but with the following differences.

Each strut module 298 has only a single linkage arm 302 that extends rearwardly from the steerer tube 104 . The link arms 302F of the front strut modules 298F are used to steer the front struts. The link arms 302R of the rear strut module 298R are only used to stabilize and maintain the rear strut in the illustrated forward straight orientation. In this way, the rear link arm 302R can effectively be fixed to the strut housing 102 instead, (see FIG. 6 ), and the steerer tube can be eliminated if desired.

A rigid, fixed-length straight link 304 is connected at one end to each front strut link arm 302F. A pair of strut cylinders 305 are provided, each pivotally connected at one end to a cylinder bracket 206 mounted on a portion of the frame 301 rearwardly of the front strut 298F. The opposite end of each straight tie rod 304 is connected to a triangular bar bracket 307, which is pivotally supported on a mounting bracket 310 fixed to the hydraulic cylinder bracket. part of the frame 301 in front of the frame 306. The bar bracket has a pair of opposed, laterally extending steering arms 312 each pivotally connected to an opposite end of a corresponding one of the steering cylinders 305 . The bar bracket 307 also has a front end 313 which is pivotally connected to the opposite end of the straight rod 304 .

The rear link arms 302R of the strut modules 298R are each connected to one end of a corresponding fixed link 308 . Each link 308 also has a second end connected to a mounting bracket 309 attached to a portion of the frame 301 . Fixed link 308 holds rear strut module 298R and rear wheel and tire assembly 296R in the illustrated straight forward orientation.

Figure 13A shows the front strut module 298F with the front wheels in a steered orientation, and Figure 13B shows the front strut module 298F with the front wheels in a straight forward orientation. For an Ackermann geometry, each wheel and tire assembly 298 has an axis of rotation ideally positioned to intersect at a common point 311 on the centerline of the rear axle at any steering angle. This means that both the front wheel and tire assembly 298F can be turned to different angles or degrees as shown. As mentioned above, since they are mechanically linked, the steering cylinder 305 can (but need not) be controlled by an on-board computer (not shown) for precise positioning.

In this embodiment, the hydraulic cylinder 305 can automatically make length adjustments to pivot the bar bracket, which in turn moves the front end 313 side to side. This movement, in turn, will move the drag link 304 to rotate the front wheel and tire assembly 298F via the front linkage arm 302F as desired.

There are many possible steering configurations and configurations possible for the truck 300 . Furthermore, many different steering geometries can also be used.

Figures 14A and 14B illustrate one of several possible steering geometries and member configurations. In this embodiment, the steering cylinder 305 is positioned forward of another bar bracket 320 having a pivot end 321 and a front end 322 . A pair of opposed and laterally extending hydraulic cylinder support brackets 324 extend from the frame 301 and are each pivotally connected to one end of a respective hydraulic cylinder 305 . The opposite end of the hydraulic cylinder and the straight tie rod 304 are connected to the bar bracket 320 near the front end 321 . In this embodiment, the telescoping of the hydraulic cylinder 305 can rotate the bar bracket side to side about the pivot end 322 and move the straight link 304, thereby rotating the front strut module 296F and the front wheel and tire assembly 298F.

The truck 300 of the various embodiments disclosed herein is less expensive than the truck 20, yet provides almost all of the advantages. Except for the truck 300 of FIG. 12 which allows the vehicle to turn about a point at the approximate center of the rear axle, each truck 300 cannot be driven perpendicular to its own axis, but the steering capability should be comparable to that of Ackerman steering used in conventional vehicles and trucks. Similar to geometric shapes.

Other embodiments may include several front strut modules which can rotate as described above but which do not drive any or at least not all of the front wheels. In this embodiment, the rear wheels can be driven as described above, but cannot rotate. Each individual drive motor for each driven wheel can be controlled as above to eliminate tire friction.

The above detailed description is for clarity of understanding only, but should not be interpreted as unnecessary limitations, and various changes will be apparent to those skilled in the art.

Claims (1)

1. truck, this truck comprises:

One framework, described framework have a front end and a rear end;

At least two trailing wheels, described trailing wheel link to each other with the part of framework and the rear end of bearer frame;

At least the first and second strut modules, first and second struts link to each other with framework near front end, and wherein each strut module comprises:

The one strut assembly that is directed, described strut assembly has a upper end, a lower end and a strut axis, this strut assembly has a strut housing, its upper end and partial fixing with the concentric truck framework of strut axis, and have a steering tube, this steering tube centers on the strut rotational with respect to the strut housing;

One spindle assemblies, this spindle assemblies has the main shaft of pair of opposing, main shaft extends and defines a wheel rotation axis from a main shaft housing, spindle assemblies is loaded in the lower end of strut assembly, be used for centering on the strut axis with strut pipe co-rotation, spindle assemblies is configured to and can moves as vibration damping with respect to the truck framework along the strut axis;

One wheel pairs and tyre assembly, each assembly make it center on the wheel rotation axis and rotate all by a corresponding main shaft supporting;

At least one driving motor, this electrical motor and a main shaft link, and are used to drive corresponding wheel and tyre assembly around the wheel turns rotational;

One steering hardware, this steering hardware are suitable for making steering tube and spindle assemblies to rotate with respect to the strut housing of each strut module independent with respect to other strut unit; And

One air cooling system, this air cooling are configured and are arranged to make the surrounding air part by electrical motor at least, thereby heat is dispersed out from least one driving motor.

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