Electric zero-turn radius mower

Abstract

A zero-turn radius lawnmower includes a chassis, a mower deck assembly, a wheel, a drive wheel, and a suspension system. The mower deck assembly is supported by the chassis. The suspension system is coupled to the chassis and includes a first rocker arm, a front suspension assembly, and a rear suspension assembly. The first rocker arm is pivotally coupled to a first side of the chassis and is configured to pivot about a first pivot axis. The first rocker arm spans between a first end and a second end. The front suspension assembly is coupled to the first end and pivotally supports the wheel. The rear suspension assembly is coupled to the second end and pivotally supports the drive wheel.

Description

ELECTRIC ZERO-TURN RADIUS MOWERCROSS-REFERENCE TO RELATED PATENT APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 472,962, filed on June 14, 2023, the entire disclosure of which is incorporated by reference herein.BACKGROUND

[0002] Zero-turn radius (ZTR) lawnmowers traditionally include drive wheels that are together able to move the lawnmower in a precise manner that allows for highly controlled grass cutting operations.SUMMARY

[0003] An exemplary embodiment relates to a zero-turn radius lawnmower. The zero-turn radius lawnmower includes a chassis, a mower deck assembly, a wheel, a drive wheel, and a suspension system. The mower deck assembly is supported by the chassis. The suspension system is coupled to the chassis and includes a first rocker arm, a front suspension assembly, and a rear suspension assembly. The first rocker arm is pivotally coupled to a first side of the chassis and is configured to pivot about a first pivot axis. The first rocker arm spans between a first end and a second end. The front suspension assembly is coupled to the first end and pivotally supports the wheel. The rear suspension assembly is coupled to the second end and pivotally supports the drive wheel.

[0004] An exemplary embodiment relates to a zero-turn radius lawnmower. The zero-turn radius lawnmower includes a chassis, a mower deck assembly supported by the chassis, and a suspension system coupled to the chassis. The suspension system includes a first rocker arm pivotally coupled to a first side of the chassis and configured to pivot about a first pivot axis, a second rocker arm pivotally coupled to a second side of the chassis and configured to pivot about the first pivot axis, and a rocker differential coupled to the first rocker arm and the second rocker arm. The first rocker arm spans between a front end and a rear end. The first pivot axis intersects the first rocker arm between the front end and the rear end. The rocker differential includes a crank that is pivotally coupled to the chassis and configured to pivot about a crank pivot axis that is perpendicular to the first pivot axis.

[0005] An exemplary embodiment relates to a zero-turn radius lawnmower. The zero-turn radius lawnmower includes a battery supported on the chassis, a mower deck assembly supported by the chassis, a caster wheel, a drive wheel, an electric drive motor powered by the battery and configured to drive the drive wheel, and a suspension system coupled to the chassis. The suspension system includes a first rocker arm pivotally coupled to a first side of the chassis and configured to pivot about a first pivot axis, a rear suspension assembly including a cradle that is pivotally coupled to a rear end of the first rocker arm, and a front suspension assembly pivotally coupled between the caster wheel and a front end of the first rocker arm. The cradle at least partially receives the electric drive motor. The front suspension assembly includes a caster body and a caster fork that is coupled to the caster wheel. The caster fork is slidably received within the caster body so that engagement between the caster fork and the caster body prevents rotation of the caster wheel about a caster axis.

[0006] This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.BRIEF DESCRIPTION OF THE FIGURES

[0007] The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which:

[0008] FIG. 1 is a top, front, right perspective view of a zero-turn radius lawnmower, according to some embodiments;

[0009] FIG. 2 is a right-side view of the zero-turn radius lawnmower of FIG. 1;

[0010] FIG. 3 is a top view of the zero-turn radius lawnmower of FIG. 1;

[0011] FIG. 4 is a top, front, left perspective view of a chassis of the zero-turn radius lawnmower of FIG. 1 and depicting a battery mounting location for powering the zero-turn radius lawnmower of FIG. 1;

[0012] FIG. 5 is a schematic illustration of a side perspective view of a suspension system of the zero-turn radius lawnmower of FIG. 1;

[0013] FIG. 6 is a linkage diagram of a portion of the suspension system of the zero-turn radius lawnmower of FIG. 1;

[0014] FIG. 7 is a linkage diagram of the suspension system of FIG. 5;

[0015] FIG. 8 is a rear perspective view of the zero-turn radius lawnmower of FIG. 1;

[0016] FIG. 9 is a rear view of the zero-turn radius lawnmower of FIG. 1;

[0017] FIG. 10 is rear perspective view of an end of the suspension system of the zeroturn radius lawnmower of FIG. 1;

[0018] FIG. 11 is a bottom perspective view of the end of the suspension system of FIG. 10;

[0019] FIG. 12 is a bottom view of zero-turn radius lawnmower of FIG. 1;

[0020] FIG. 13 is a top, front, left perspective view of an end of the suspension system of the zero-turn radius lawnmower of FIG. 1;

[0021] FIG. 14 is a bottom perspective view of the zero-turn radius lawnmower of FIG. 1;

[0022] FIG. 15 is a bottom, front perspective view of the zero-turn radius lawnmower ofFIG. 1;

[0023] FIG. 16 is cross sectional view of a rotary implement module of the zero-turn radius lawnmower of FIG. 1;

[0024] FIG. 17 is a top, left perspective view of the rotary implement module of FIG. 16 and depicting a scalp rail;

[0025] FIG. 18 is a top, front, left perspective view of the scalp rail of FIG. 17;

[0026] FIG. 19 is a top perspective view of a rotary implement of the rotary implement module of FIG. 16;

[0027] FIG. 20 is a top view of the rotary implement of FIG. 19;

[0028] FIG. 21 is a bottom view of the rotary implement of FIG. 19;

[0029] FIG. 22 is a perspective view of a rotary implement of the rotary implement module of FIG. 16;

[0030] FIG. 23 is a pressure plot of a side-discharge three spindle mower deck of the zeroturn radius lawnmower of FIG. 1; and

[0031] FIG. 24 a pressure plot of a rear-discharge two-spindle mower deck of the zeroturn radius lawnmower of FIG. 1.DETAILED DESCRIPTION

[0032] Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

[0033] The present disclosure is directed to battery-powered outdoor power equipment or chore products. A “chore product” as used herein refers to any type of equipment, machine, or vehicle that may be used to perform a chore (e.g., an outdoor chore, an indoor chore, lawn care, etc.). For example, a chore product may include a motor, a pump, an actuator, a compressor, and / or another device that is electrically powered to operate some function of the chore product to facilitate performing a chore. In some embodiments, a chore is a task performed, either by a user or autonomously, at or near a household, a farm, an agricultural facility, a building, a sidewalk, a park, a parking lot, a forest, a field, and / or a lawn. In some embodiments, a chore product transports an operator and performs a chore. In some embodiments, a chore product autonomously operates to perform a chore without an operator being present on the chore product or physically / manually manipulating the chore product.

[0034] Referring to the figures generally, the various exemplary embodiments disclosed herein relate to systems, apparatuses, and methods for an electrically-powered zero-turn radius (ZTR) lawnmower. The ZTR has a chassis that supports a deck that includes one ormore motors that drive one or more blades. The ZTR includes a suspension system that may include bilateral rocker arms that couple independent wheel suspensions about a mutual pivot axis. The independent wheel suspensions permit the wheels to independently travel relative to the respective end of the respective rocker arm. The suspension system includes rear suspension assemblies that have rear suspension cradles that respectively support an electric motor and a drive wheel. The suspension system includes front suspension assemblies that have a parallel linkage that permits the front wheel to oscillate relative to the end of the rocker arm. The motion of the drive wheels relative to the ends of the rocker arms is governed by at least one shock absorber (e.g., spring damper). The shock absorbers oppose motion (e.g., rotation and translation) of the drive wheels relative to the ends of the rocker arms. The pivoting motion of the rocker arms around the pivot axis may be linked by a rocker differential. By including rocker arms and independent suspension assemblies coupled thereto, the ZTR is able to provide a smoother riding experience that is able to more readily adapt to undulations in terrain that might otherwise cause the chassis and deck of the ZTR to tilt, which could impact both mowing quality and rider experience. The suspension system can allow for an increased range of motion and a highly configurable ride experience that allows the ZTR to be optimized to perform specific tasks.

[0035] Although described in the context of a ZTR, the suspension systems described herein can be applicable to other chore products, including outdoor power equipment, indoor power equipment, light vehicles, aerial man lifts, floor care devices, golf carts, lift trucks and other industrial vehicles, recreational utility vehicles, industrial utility vehicles, and lawn and garden equipment. Outdoor power equipment may include lawn mowers, riding tractors, snow throwers, pressure washers, tillers, log splitters, walk-behind mowers, riding mowers, and turf equipment such as spreaders, sprayers, seeders, rakes, and blowers. Outdoor power equipment may, for example, use one or more electric motors to drive an implement, such as a rotary blade of a lawn mower, a pump of a pressure washer, the auger of a snow thrower, the alternator of a generator, and / or a drivetrain of the outdoor power equipment. Indoor power equipment may include floor sanders, floor buffers and polishers, vacuums, etc.

[0036] Referring now to FIGS. 1-3, outdoor power equipment, shown as ZTR 10, is provided. The ZTR 10 generally includes a chassis 12 that supports front wheels 14 (e.g., front wheel 14A, front wheel 14B, etc.), rear drive wheels 16 (e.g., rear wheel 16A, rear wheel 16B, etc.), and a deck assembly 18 (e.g., cutting deck, mower deck, deck assembly, etc.). Anoperator seat 20 is supported by the chassis 12 and is positioned toward the rear of the chassis 12. In some embodiments, and as explained below, the operator seat 20 extends above a battery assembly 22 that powers the ZTR 10. A series of operator controls 24 may be positioned within an access space near the operator seat 20 and are configured to receive physical commands from a user to help operate (e.g., drive, steer, turn-on, turn-off, perform a chore action, etc.) the ZTR 10. For example, the ZTR 10 may include pedals that are positioned within a foot space below the operator seat 20 and are configured to receive physical commands from a user to help drive and control the ZTR 10. As another example, the ZTR 10 may include two or more handlebars, and the handlebars may extend upwardly from the chassis 12, toward the operator seat 20. For example, the handlebars can be used to control the motors (shown below) individually and independently and / or transmission elements that drive the rear drive wheels 16, which allows the ZTR 10 to perform precise and tight turning maneuvers to execute different operations (e.g., mowing, blowing, mulching, etc.). In some examples, the handlebars include a biasing system to help clock the handlebars relative to the chassis 12. The biasing system can include one or more springs, for examples, that act against movement of the handlebars such that when the handlebars are released, the handlebars return to a home position. In another example, motors and encoders are used to monitor a position of the handlebars and activate to return the handlebars to a home position once the detected torque on the motors falls below a threshold value, which may be indicative of a situation where the operator released the handlebars. In some embodiments, the operator controls 24 of the ZTR 10 may include handlebars (e.g., the handlebars described above), a joystick, a steering wheel, foot pedals, and / or a combination thereof.

[0037] In some examples, one or more inputs 26 (e.g., buttons, knobs, handles, etc.) are positioned near the operator seat 20 and configured to selectively activate and / or control the one or more motors (e.g., rotary motors, implement motors, blade motors, etc.) positioned on the deck assembly 18 to drive a rotary implement (e.g., blades) to cut grass, brush, weeds, flowers, etc. The inputs 26 can include blade rotation speed controls, which allow a user to control blade speed more precisely at a preferred angular speed. Additional inputs 26 can be provided to adjust a height of the deck assembly 18 relative to the chassis 12 as well.

[0038] In some embodiments, the ZTR 10 includes an accessory 28 positioned behind the operator seat 20. The accessory 28 may be or include a second battery assembly that may power at least a portion of the ZTR 10. For example, the accessory 28 may be a batteryassembly that can augment the electrical performance and output of the battery assembly 22. In some embodiments, the accessory 28 may include a battery assembly that is larger (more voluminous, larger discharge capacity, larger energy storage capacity, etc.) than the battery assembly 22.

[0039] In some embodiments, the accessory 28 may be swapped for a second accessory 28. For example, the accessory 28 may be a battery pack, and the battery pack of a first accessory 28 may be swapped with a second accessory 28 having a different battery pack. For example, the accessory 28 may be a battery assembly that is discharged (e.g., depleted) and selectively replaced by a second accessory 28 having a battery pack that is charged (e.g., a fresh battery pack). In some embodiments, the accessory 28 may be swapped for a second accessory 28 and the second accessory 28 may be of the same accessory type as the first accessory 28 (e.g., a battery pack). In some embodiments, the second accessory is a different accessory type, such as a chemical storage tank (e.g., gas tank, sprayer system, etc.) type, a counterweight system type, a storage compartment type, a refrigerated compartment type, an ice box type, a speaker system type, a string trimmer storage rack type, a battery charger type, a roll overprotective structure (e.g., roll bars, etc.) type, a seeder system type, a turf roller type, etc. In some embodiments, the accessory 28 is suspended from the chassis 12. For example, the accessory 28 may be supported by the chassis 12 such that the accessory 28 does not rest on the ground when the accessory 28 is coupled to the chassis 12 and is transported during travel of the chassis 12.

[0040] In some embodiments, the ZTR 10 spans between a first end, shown as front end 30 and a second end, shown as rear end 32. In some embodiments, the front end 30 includes the front wheels 14. In some embodiments, the rear end 32 includes the rear wheels 16.

[0041] With additional reference to FIG. 4, the chassis 12 is shown in additional detail. The chassis 12 generally includes a front frame 40, a mid-frame 42, a rear frame 44 (e.g., a rear saddle), and a core frame 46. The chassis 12 may be at least partially made of cast aluminum and steel castings. In some embodiments, the front frame 40 is forward of the midframe 42, the rear frame 44 and the core frame 46. The mid-frame 42 may be rearward of the front frame 40 and forward of the rear frame 44. The mid-frame 42 may be couple the front frame 40, the rear frame 44, and the core frame 46. The front frame 40 may be coupled to a first end of the mid-frame 42, the rear frame 44 may be coupled to an opposing second endof the mid-frame 42, and the core frame 46 may be coupled to the mid-frame 42 between the first end of the mid-frame 42 and the second end of the mid-frame 42.

[0042] In some embodiments, the core frame 46 is a rectangular box frame that is coupled to the mid-frame 42 at a first end of the core frame 46. For example, an upper end of the core frame 46 may be coupled between a pair of opposing walls 48 of the mid-frame 42. The core frame 46 may be coupled to the mid-frame 42 below the operator seat 20. For example, the bottom of the operator seat 20 may be coupled to the mid-frame 42 above the top end of the core frame 46. In some embodiments, the centroid and / or center of mass of the core frame 46 is below the operator seat 20. In some embodiments, the operator seat 20 covers the top end of the core frame 46. The core frame 46 may house the battery assembly 22. The core frame 46 battery may hold the battery assembly 22 below the front frame 40, mid-frame 42, and rear frame 44, which lowers the center of mass of the chassis 12. In some embodiments, the core frame 46 is below the mid-frame 42 and not the front frame 40 nor the rear frame 44.

[0043] As shown in FIG. 1, 2, 4, and 8, the core frame 46 includes a battery receptacle 47. The battery receptacle 47 receives the battery assembly 22. In some examples, the battery assembly 22 is one or more removable and rechargeable battery packs that are coupled together in a parallel configuration. For example, the battery assembly 22 can be formed of one or more battery packs similar to the battery packs shown and described within PCT Patent Application Publication No. WO2021 / 021874, filed July 29, 2020, the contents of which are hereby incorporated herein by reference in their entirety. In some examples, the battery assembly 22 can be formed from one or more battery packs similar to the battery pack shown and described within PCT Patent Application Publication No. WO2024 / 059329, filed September 18, 2023, the contents of which are incorporated herein by reference in their entirety. In still other examples, the battery assembly 22 is configured as a fixed battery pack that is formed of several cell module assemblies arranged in a parallel configuration or semiparallel configuration that is configured to output a voltage between about 24V and about 48V. An example battery pack arranged in this manner is shown and described in commonly owned PCT Patent Application Publication No. WO2021 / 113251, filed December 1, 2020, the contents of which are hereby incorporated herein by reference in their entirety. The battery assembly 22 can include one or more external charging ports (not shown) that allow the battery assembly 22 to be coupled with an external power source, such as a wall socket or utility source, using a plug assembly. In some embodiments, the battery receptacle 47 housesa battery that remains onboard the ZTR 10, (e.g., a built-in battery), and the accessory 28 may be a removable battery assembly or swappable battery assembly similar to the battery assembly 22.

[0044] In some embodiments, the chassis 12 can support a compartment that receives a plurality of controllers (e.g., processors, microprocessors, micro controllers, one or more processors coupled to one or more non-transitory memory devices storing instructions thereon that when executed by the one or more processors cause the one or more processors to perform one or more operations), that are arranged to control motors on the ZTR 10. The controller compartment can be positioned near the operator seat 20, and / or within the battery receptacle 47, and / or below a foot panel of the ZTR 10, which extends outwardly away from the midframe 42 toward the front end 30 to define a rest area for the feet of an operator. In some examples, each motor on the ZTR 10 has its own dedicated controller, and each of the controllers are configured to communicate with one another (e.g., using a CAN bus, using a wired connection, using Bluetooth or other wireless protocols) to allow communication throughout the system.

[0045] In some embodiments, the front frame 40 is U-shaped. In some embodiments, the rear end of the front frame 40 engages the front ends of the opposing walls 48 of the midframe 42. In some embodiments, the front end of the front frame 40 includes a cross member. In some embodiments, the chassis 12 includes a chassis gap 50 defined between the walls 48 and the pocket of the u-shape of the front frame 40. In some embodiments, the front frame 40 includes a pair of opposing walls that join together at the front end of the front frame 40.

[0046] In some embodiments, the rear frame 44 defines a crank pivot hole 52. The crank pivot hole 52 may extend along a crank pivot axis 54. The rear frame 44 may include a cage 56. The cage 56 may define a cage pivot hole 58 that extends along the crank pivot axis 54. In some embodiments, the cage pivot hole 58 is spaced from the crank pivot hole 52 along the crank pivot axis 54. In some embodiments, the interior surfaces of the cage 56 define a cage space 60 therebetween. The cage 56 may include a cage body 62 from which cage arms 64 extend radially around the crank pivot axis 54. The cage body 62 may be spaced from the rear frame 44 by a cage gap 66.

[0047] In some embodiments, the chassis 12 is coupled together using one or more crossbeams. The front frame 40, mid-frame 42, rear frame 44, and core frame 46 can berigidly coupled (e.g., welded, adhesively coupled, etc.). In some embodiments, the front frame 40, mid-frame 42, rear frame 44, and / or core frame 46 are collectively a unitary body. For example, the front frame 40, mid-frame 42, rear frame 44, and / or core frame 46 may be formed together as a casting or forging or may be manufactured via an additive manufacturing process (e.g., metal printing, 3-d printing, etc.). Additional brackets and structural members (e.g., bar stock, box steel or aluminum, channels, etc.) can also be used to reinforce the front frame 40, mid-frame 42, rear frame 44, and / or core frame 46, and / or couplings between the front frame 40, mid-frame 42, rear frame 44, and core frame 46. For example, the chassis 12 can include one or more stabilizing members (e.g., supports, stays, etc.), shown as support arms 70. Support arms 70 may be pivotally coupled to the mid-frame 42 at a first end of the support arm 70 and may be pivotally coupled to the core frame 46 at a second end of the support arm 70. In some embodiments, the front frame 40, mid-frame 42, rear frame 44, and core frame 46 are formed separately and assembled together.

[0048] As shown in FIGS. 1-3, the chassis 12 supports a suspension system 100 that in turn supports and positions the front wheels 14 and the rear wheels 16. The suspension system 100 suspends the chassis 12 from the ground surface and absorbs vibrations and impacts experienced by front wheels 14 and / or rear wheels 16. The suspension system 100 absorbs vibratory motions imparted by the travel of the wheels across ground surfaces of varying topography (e.g., bumpy surfaces, dimpled surfaces, pitted surfaces, grooved surfaces, etc.). The suspension system 100 permits the wheels 14, 16 to rotate, oscillate, and travel, relative to the chassis 12.

[0049] The suspension system 100 may couple the front wheels 14 and the rear wheels 16 to the chassis 12. In some embodiments, the suspension system 100 may be symmetric about a plane of symmetry, shown as symmetry plane 102. In some embodiments, the suspension system 100 is pivotally coupled to the chassis 12 and pivots around a pivot axis 104 (e.g., a rocker pivot axis, a primary pivot axis, etc.). The chassis 12 may pivot around the pivot axis 104 relative to the suspension system 100. In some embodiments, the chassis 12 may pivot around the pivot axis 104 relative to the suspension system 100 within a predefined angular envelope (e.g., ±7 degrees, ±10 degrees, etc.). For example, the suspension system 100 may include one or more mechanical stops (e.g., contacts, bumpers, locks, pin locks, etc.) that restrict rotational motion of the chassis 12 relative to the suspension system 100. For example, during testing of the suspension system 100, the angular travel of the chassis 12relative to the suspension system 100 was approximately ±4 degrees, and the angular travel of the chassis 12 relative to the suspension system 100 was kept within an angular envelope of ±7 degrees. The angular envelope may permit the chassis 12 to pivot around the pivot axis 104 but prevent the ends of the chassis 12 and / or components coupled to the chassis 12 from striking the ground. For example, the center of balance of the chassis 12 may be offset (e.g., forward or rearward) from the pivot axis 104. The mechanical stops (e.g., bumpers, bump faces, etc.) may prevent the chassis 12 from freely rotating around the pivot axis 104 due to a center of balance that is offset from the pivot axis 104. In some embodiments, the bump stop is tuned compliant to soften impact upon the suspension system 100 being limited by the bump stop. In some embodiments, the hardness (e.g., measured via a durometer) of the urethane and geometry of the bump stop are determinative of spring rate and dampening characteristics. In some embodiments, the bump stop could be movable / adjustable to permit customizing the travel of the suspension system 100 relative to the chassis 12.

[0050] In some embodiments, the deck assembly 18 is heavier than the accessory 28, and the center of mass of the deck assembly 18 may be forward of the pivot axis 104, which, in turn, places the balance point of the chassis 12 forward of the pivot axis 104 and between the front wheels 14 and the rear wheels 16. In some embodiments, the chassis 12 is selectively locked in a fixed angular relation to the suspension system 100 around the pivot axis 104. For example, the suspension system 100 may be locked by one or more detainers (e.g., plunger pins, set screws, friction etc.) or shaft braking mechanisms that prevent the chassis 12 from pivoting around the pivot axis 104.

[0051] In some embodiments, the chassis 12 is self-righting, for example, the core frame 46 and the battery assembly 22 may be heavy and cause the chassis 12 center of mass to be biased toward a position below the pivot axis 104. For example, the weight distribution of the chassis 12 may effectuate a passive self-balancing system. In some embodiments, the chassis 12 is balanced around the pivot axis 104 by an active self-balancing system (e.g., an electronically actuated balancing system).

[0052] As utilized herein, alphabetic suffixes (e.g., “A”, “B”, “C”, etc.) on numeric element numbers designate instances of same or similar elements. In particular, the alphabetic suffix "A" indicates an instance on the right side of the suspension system 100 and the alphabetic suffix "B" indicates an instance on the left-side of the suspension system 100.In general, the description herein of the components with the suffix “A” applies symmetrically about the symmetry plane 102 to the components with the suffix “B ”

[0053] In some embodiments, the suspension system 100 is a six-way independent suspension. For example, front wheel 14A, front wheel 14B, rear wheel 16A, rear wheel 16B may be configured to travel independently and relative to one another, and the pairs of front and rear wheels (e.g., front wheel 14A and rear wheel 16A) may travel relative to each other. In some embodiments, the suspension system 100 is configured to accommodate both large scale ground surface variations (e.g., slopes, hills, etc.) and micro level ground surface variations (e.g., potholes, mounds, sprinkler heads, hoses, stones, bumps, sticks, etc.). For example, the suspension system 100 may balance: (i) the front wheel 14A and rear wheel 16A relative to the front wheel 14B and rear wheel 16B; and (ii) the front wheel 14A relative to the rear wheel 16 A, and the front wheel 14B relative to the rear wheel 16B.

[0054] As shown in FIGS. 1-3 and 5, the suspension system 100 includes rocker arms 110. Rocker arms 110 can include rocker arm 110A and rocker arm HOB. In some embodiments, the rocker arm 110A includes a pivot 112 A. The pivot 112A may include bushings and / or bearings and may pivotally couple the rocker arm 110A to the chassis 12. The rocker arm 110A can pivot around the pivot axis 104 via the pivot 112A.

[0055] In some embodiments, the rocker arm 110A and the rocker arm HOB are selectively locked in a fixed angular relation to the chassis 12 around the pivot axis 104. For example, the rocker arm 110A and the rocker arm 110B may be locked by one or more detainers (e.g., plunger pins, set screws, friction etc.) or shaft braking mechanisms that prevent the rocker arm 110A and the rocker arm 110B from pivoting around the pivot axis 104. For example, the chassis 12 may include one or more holes 49 (e.g., bore holes, through holes, blind holes, etc.) configured to receive a sliding member (e.g., a pin, a dowel, a rod, etc.) that engages and restricts movement of the rocker arm 110A and the rocker arm 110B relative to the chassis 12 (see, e.g., FIG. 4). For example, a pin may slide within hole 49 and eliminate the relative motion between the rocker arm 110A and the rocker arm 110B and the chassis 12. That is, the rocker arm 110A and the rocker arm 110B can be “locked” (e.g., pinned, clamped, trapped, etc.) relative to the chassis 12 to prevent the rocker arm 110A and the rocker arm 110B from rotating relative to the chassis 12. The pin(s) may be selectively removed or disengaged to “unlock” the rocker arm 110A and the rocker arm 110B relative tothe chassis. In some embodiments, one of the rocker arms (e.g., rocker arm 110A) may be locked relative to the chassis 12 which, in turn, may lock the other rocker arm HOB via a linkage that couples the motion of the rocker arm 110A with the rocker arm HOB (e.g., via the differential 164). In the locked position, the wheels move independently with respect to the rocker arm 110A and the rocker arm 110B. That is, when the rocker arm 110A and the rocker arm 110B are held in a fixed relation with the chassis 12, the suspension system 100 may be a four-wheel independent suspension. However, in the unlocked position, the wheels move independently with respect to the rocker arm 110A and the rocker arm 110B, and the rocker arm 110A and the rocker arm 110B can pivot relative to the chassis 12. That is, when the rocker arm 110A and the rocker arm 110B can pivot relative to the chassis 12, the suspension system 100 may be a five-way independent suspension. The “unlocking” and “locking” of the rocker arm 110A and the rocker arm HOB with respect to the chassis 12 can facilitate user comfort and adaptable suspension performance, according to some embodiments.

[0056] As shown in FIGS. 2-3, the rocker arm 110A spans between a front end 114A and a rear end 116A. In some embodiments, the pivot axis 104 intersects the rocker arm 110A between the front end 114A and the rear end 116A. In some embodiments, the rocker arm 110A is arcuate between the front end 114A and the rear end 116A. For example, the rocker arm 110A may arc downward between the first end 114A and the rear end 116A (see, e.g., FIG. 2). In some embodiments, the rocker arm 110A is arcuate between the front end 114A and the rear end 116A in a plane perpendicular to the first plane (see, e.g., FIG. 3). That is, the rocker arm 110A may arc downward in a first plane, and may be arcuate in a second plane that is perpendicular to the first plane. The downward arcing of the rocker arm 110A may accommodate portions of a mower deck assembly 18 that extend within a space defined between the rocker arm 110A and the ground surface. In some embodiments, the rocker arm 110A facilitates a taller space (e.g., clearance) below the chassis 12 (i.e., between the chassis 12 and the ground surface). The clearance can facilitate a mower deck (e.g., mower deck assembly 18) and / or other under-chassis implements or attachments (e.g., a battery pack, a fluid tank, a speaker system, a fan, etc.), shown as accessory battery 51, and facilitate maneuvering the mower deck assembly 18 and / or the other under-chassis implements or attachments within the space below the chassis 12. For example, accessory battery 51 may be coupled to (e.g., fastened, bonded, adhered, welded, magnetically attracted, snap fit onto, etc.) an underside of the chassis 12 and above the mower deck assembly 18. For example,the accessory battery 51 may be coupled to the underside of a foot plate 53 (e.g., a foot rest, a floor plate, etc.) of the chassis 12 (see, e.g., FIG. 15). Advantageously, the taller clearance can enable axial flow mower decks (e.g., the mower deck assembly 18) where the cutting action brings the grass up and over the blade spindle, and reduces back-pressure against the blades, in turn, reducing blade torque and energy consumption. The efficient mower deck 18 can reduce the energy consumed during operation and facilitate utilizing a smaller (e.g., less heavy, lesser capacity, lesser weight, etc.) battery. The taller clearance below the chassis 12 and rocker arms 110A, HOB can enable mounting other equipment (e.g., accessory battery 51) under the footwell area. Advantageously, the taller clearance below the chassis 12 and rocker arms 110A, HOB can facilitate a taller mower deck assembly (e.g., mower deck assembly 18) that facilitates energy efficient cutting operation, but can also accommodate other types of mower decks, such as an in-plane rear or side discharge deck configuration.

[0057] In some embodiments, the front end 114A may be coupled to the front wheel 14 A. The rear end 116A may be coupled to the rear wheel 16 A. The rear end 116A may include a rear pivot 118 A. The rear pivot 118A may pivotally couple a rear suspension assembly 120 A.

[0058] In some embodiments, the rear suspension assembly 120 A may pivot relative to the rear end 116A around a rear pivot axis 122A. The rear pivot axis 122A may be parallel to the pivot axis 104. For example, the rear end 116A, rear suspension assembly 120A, and rear wheel 16A may pivot around the pivot axis 104, and the rear suspension assembly 120A and rear wheel 16A may pivot relative to the rear end 116A around the rear pivot axis 122A.

[0059] In some embodiments, the rear suspension assembly 120 A includes a damper (spring damper, pneumatic damper, hydraulic cylinder, etc.), shown as rear shock absorber 124A. The rear shock absorber 124A may be coupled to the rear end 116A at a first end and coupled to the rear suspension assembly 120A at a second end. The shock absorber 124A may be pivotally coupled to the rear end 116A and / or the rear suspension assembly 120A. The shock absorber 124A may have a nominal length between the first end and second end. When the shock absorber 124A is subjected to a load, (e.g., an axial force between the ends of the shock absorber 124A), the distance between the first end and the second end may change and the energy imparted into the shock absorber 124A may be stored by the shock absorber 124A (e.g., as hydraulic pressure, as spring force, etc.), and / or dampened (e.g., dissipated, captured and slowly discharged, etc.). The axial displacement (e.g., change inlength relative to the nominal length) of the shock absorber 124A may permit the rear wheel 16A to travel approximately 4 inches around the rear pivot axis 122A relative to the rear end 116A. In some embodiments, the shock absorber 124A may permit the rear wheel 16A to travel within an angular envelope (e.g., ± 10 degrees, ± 5 degrees, etc.) around the rear pivot axis 122 A.

[0060] The rear suspension assembly 120A is generally formed of an independently- mounted rear suspension cradle 126A, which supports one of the rear drive wheels 16 (rear drive wheel 16A) and associated drive motor(s) (e.g., hub motor, geared hub motor, etc.). The rear suspension cradle 126A is coupled to the rear end 116A and the shock absorber 124A. The rear suspension cradle 126A is configured to pivot relative to the chassis 12 to help absorb impacts caused by sudden changes in topography or objects along the path of the ZTR 10.

[0061] The rear suspension cradle 126A is independently mounted to the rocker arm 110A in a way that permits rotation through a finite range (e.g., + / - 30 degrees, + / - 15 degrees, etc.). In some embodiments, the allowable range of motion of each rear suspension cradle 126 A, 126B can be customized depending on the type of job being performed by the ZTR 10. In some examples, the independent suspension assembly allows for a greater range of motion of the rear wheel 16A relative to the chassis 12 than traditional rear axle suspensions.

[0062] In some embodiments, the rear suspension cradle 126A is formed by a multi-panel construction having a generally trapezoidal shape. For example, the rear suspension cradle 126 A can include a first panel, a second panel, and a spacer plate positioned between and coupling the first panel and the second panel together. In some examples, the first panel and the second panel are made from aluminum or steel that is laser-cut, cast, stamped, machined, or otherwise formed into shape. In some embodiments, the rear suspension cradle 126A is unitary body. For example, the rear suspension cradle 126A may be cast, forged, milled, 3D printed, etc.

[0063] In some embodiments, the rear suspension cradle 126A is formed with a series of mounting features that allow the coupling of the rear suspension cradle 126A to the chassis 12. For example, a first end of the rear suspension cradle 126A can include an axle passage 130A (see, e.g., FIG. 12). The axle passage 130A can be formed through the rear suspension cradle 126A and receive a pivot pin 132A. In some embodiments, the axle passage 130 isreceived within a clevis (e.g., fork) formed at the rear end 116A of the rocker arm 110A and the pin 132A is a clevis pin. In some embodiments, the pivot pin 132A extends approximately parallel to the pivot axis 104, such that rear suspension cradle 126A is configured to rotate around the rear pivot axis 122 A and the pivot axis 104.

[0064] In some embodiments, the second end of the rear suspension cradle 126A includes a nub 134A (e.g., protuberance, ear, etc.) configured to facilitate a second coupling between the rear suspension cradle 126A and the rocker arm 110A. The nub 134A includes a hole or pocket that is configured to receive a pin for coupling the rear suspension cradle 126A to the shock absorber 124A.

[0065] Shock absorber 124A can include a spring and damper assembly that is configured to oppose rotation of the rear suspension cradle 126 A in each direction around the rear pivot axis 122A. In some embodiments, shock absorber 124A is a dashpot-style damper including a body and a piston. In some embodiments, a spring is received around and extends around a portion of each of the body and the piston. In some embodiments, the damper and the spring are arranged in series.

[0066] In some embodiments, the shock absorber 124A opposes motion of the rear suspension cradle 126A and dissipates energy imparted on the rear drive wheels 106, which reduces impacts felt through the operator seat 20 and improves ride quality. For example, if the rear suspension cradle 126A shown in FIG. 5 was rotated clockwise around the rear pivot axis 122A defined by the rear pivot 118A, the tension on the spring of the shock absorber 124 A will increase, urging the rear suspension cradle 126 A back toward a home position (e.g., equilibrium, rest, a static condition). Simultaneously, fluid within the body of the damper of the shock absorber 124A opposes the movement of the piston and dissipates some of the energy imparted onto the rear suspension cradle 126A. Together, the spring and damper absorb and dissipate some of the shock forces. Likewise, if a counterclockwise force is imparted onto the rear suspension cradle 126A (e.g., from hitting a pothole or bump), the rear suspension cradle 126A begins to rotate around the rear pivot axis 122A. The spring of the shock absorber 124A compresses, and pushes the rear suspension cradle 126A away, toward the home position. Simultaneously, movement of the piston within the body of the damper of the shock absorber 124A is opposed by fluid within the body, which slows down and reduces the energy transmitted into the rear suspension cradle 126 A. Together, the springand damper help to reduce the impact and oscillation that might otherwise be transmitted through to the operator via the operator seat 20. In some embodiments, if a counter-clockwise force (i.e., counter-clockwise torque) or clockwise force (i.e., clockwise torque) is imparted onto the rear suspension cradle 126A (e.g., from hitting a pothole or bump), the rear suspension cradle 126A may begin to rotate around the rear pivot axis 122A and / or the pivot axis 104.

[0067] In some examples, the shock absorber 124A can be configured to provide a variable force and / or adjust the range of motion of the rear suspension cradle 126A. For example, the damper can be a gas spring or pneumatic cylinder configured to be operated at different pressure ranges. Accordingly, the amount of rotation of the rear suspension cradle 126A relative to the rear pivot axis 122A can be adjusted to accommodate different types of surfaces to be mowed or traveled over by the ZTR 10.

[0068] For example, mowing a very low-cut surface that requires precision (e.g., a putting green surface on a golf course, etc.) can be best executed with a very tight suspension that will not cause the deck assembly 18 to move significantly when the ZTR 10 travels over small hills and other objects. When the ZTR 10 is likely to travel at lower speeds, the degree of travel of the suspension can be reduced without significantly impacting ride quality. In contrast, in situations where the ZTR 10 will be traveling at higher speeds and over rougher terrain, the shock absorber 124A can be relaxed to allow greater or freer movement of the rear suspension cradle 126A relative to the rear pivot axis 122A. For example, gas can be removed or depressurized from the dampers of the shock absorber 124A, which can allow for a greater range of motion and freer motion. In some examples, the dampers are configured to automatically adjust an amount of gas pressure within the damper based upon a detected velocity of the ZTR 10. Further in these examples, at higher speeds, greater ranges of motion for the rear suspension cradle 126A can be permitted, while at lower speeds, the rear suspension cradle 126 A will remain more stationary and rigid. In some embodiments, the shock absorbers of the ZTR 10 (e.g., shock absorber 124A) can be adjusted to tune the suspension system 100 for time-varying load (e.g., weight) distributions on the chassis 12.

[0069] In some embodiments, the amount of force within the damper can vary between the shock absorber 124A and the shock absorber 124B. Pressurized gas can be supplied toeach of the dampers from one or more electric pumps that are driven by the electric power from the battery assembly 22.

[0070] As shown in FIGS. 9-12, the rear suspension cradle 126 A receives and supports an independent electric motor assembly 300A, according to some embodiments. The electric motor assembly 300 A can be a traction motor that generally includes a motor body 302 A that receives and supports a stator and rotor assembly. The motor body 302A can include a series of ribs that undulate around the outer surface of the motor body 302 A. In some embodiments, the electric motor assembly 300A is an induction motor that includes a series of copper coils received within the motor body 302 A to drive the rotor to impart motion onto a drive shaft extending from the motor body 302 A. The drive shaft may rotate about a motor drive shaft axis 303 A. In some embodiments, the drive shaft is directly coupled to an axle 304A that is supported by the rear suspension cradle 126A. In some embodiments, the drive shaft is mechanically coupled to the axle 304 A using a belt or chain that drives a pulley or sprocket. In these examples, rotation of the drive shaft drives the belt or chain, which in turn rotates a pulley or sprocket that is rotationally locked (e.g., via a keyed joint) with the axle 304A. In some embodiments, the axle 304A is formed as a spindle assembly 306A that is mounted to the rear suspension cradle 126 A. In some embodiments, the axle 304 A extends along a rear wheel rotation axis 136A. The rear wheel 16A may rotate about the rear wheel rotation axis 136A. Rotation of the rear wheel 16A around the rear wheel rotation axis 136A may be powered by the independent electric motor assembly 300 A.

[0071] The electric motor assembly 300 A can be received within a pocket formed laterally inwardly. The pocket may be formed on a first side of the rear suspension cradle 126A, and the spindle assembly 306 A may be coupled to an opposite side of the rear suspension cradle 126A. The electric motor assembly 300A may be an unsprung mass.

[0072] As shown in FIGS. 5-7 and 13, the front end 114A of the rocker arm 110A supports a front suspension assembly 140 A. The front suspension assembly 140 A includes a first link 142 A and a second link 144 A. The first link 142 A and the second link 144 A are pivotally coupled to the front end 114A of the rocker arm 110A at their first end, and pivotally coupled to a caster body 146 A at a second end. The first link 142 A and the second link 144 A may be coupled between the front end 114A and the caster body 146A in a parallel linkage arrangement. For example, the first link 142 A and the second link 144 A may extend betweenthe front end 114A and the caster body 146 A parallel relative to each other. The length of the first link 142A and the length of the second link 144A may be the same. The second ends of the links 142 A, 144 A may move together and stay in a plane parallel to a plane containing the first ends as each linkage moves.

[0073] In some embodiments, the caster body 146A extends along a caster axis 148A. The front wheel 14A may swivel, pivot, and / or rotate around the caster axis 148A. For example, the caster body 146A may be coupled to a caster fork 154A (e.g., a swivel fork) that couples the front wheel 14A, and the caster fork 154A may rotate about the caster body 146. The caster axis 148 may have a fixed angular relationship to the second ends of the linkages 142A, 144A. In some embodiments, the front suspension assembly 140A is coupled to the front end 114A such that the caster body 146A translates along the caster axis 148A relative to the front end 114A. The translation of the caster body 146A along the caster axis 148A may be governed by a front shock absorber 150A. The front shock absorber 150A may include some or all of the features and functions of the shock absorber 124A. For example, the front shock absorber 150 may be a spring damper assembly. In some embodiments, the shock absorber 124A may include some or all of the features and functions of the front shock absorber 150A.

[0074] In some embodiments, the front shock absorber 150A has a nominal length that may be adjusted to tune the suspension system 100. For example, the front shock absorber 150A may have an adjustable length strut. The front shock absorber 150A may permit adjustment of the sag, compression, and rebound of the front suspension assembly 140A. For example, the spring may be pre-tensioned, the strut may be elongated, the damper orifice may be reduced, etc. The length of the front shock absorber 150A and the deflection range of the front shock absorber 150A may limit the travel of the caster body 146A relative to the front end 114A. A maximum and minimum length of deflection of the shock absorber 150A may be limited by a mechanical stop (e.g., a rubber bumper, etc.). In some embodiments, the shock absorber 150A is coupled between the front end 114A and the caster body 146A with one or more spacers.

[0075] In some embodiments, the front wheel 14A is configured to rotate about a front wheel axis 152A. In some embodiments, the front wheel axis 152A can be rotated about the caster axis 148A. In some embodiments, the caster axis 148A is perpendicular to the front wheel axis 152A.

[0076] As shown in FIG. 13, the caster body 146 A may include a caster fork 154 A that supports the front wheel 14A via a pin that extends along the front wheel axis 152A, according to some embodiments. The caster body 146A may be a cylindrical flanged pipe shape that extends along the caster axis 148A. The caster fork 154A may include a caster axle 156A. The caster axle 156A may extend along the caster axis 148A through the caster body 146A. An end of the caster axle 156A may define a first shoulder 158A. The first shoulder 158A may be configured to engage the rim 160 A of a first end of the caster body 146 A. In some embodiments, the first shoulder 158A is configured to engage the rim 160A such that the caster axle 156 is prevented from rotating around the caster axis 148A. For example, the rim 160 A may include notches, knurling, grooves, teeth, a tractive material (e.g., a rubber material, etc.) that may engage the shoulder 158A and dampen or prevent the caster axle 156A from rotating around the caster axis 148A. The second end of the caster axle 156A may define a second shoulder 161 A. The second shoulder 161 A may include a spring 162 A that is configured to bias the second shoulder 161 A away from the caster body 146A. The biasing force of the spring 162A may be overcome (e.g., the spring 162 is compressed) when the front wheel 14A supports at least a portion of the weight of the ZTR 10. However, when the biasing force of the spring 162A is not overcome (e.g., when wheel 14A does not support at least a portion of the weight of the ZTR 10), the spring 162A and / or the weight of the wheel 14A and the weight of the caster fork 154A may cause the caster axle 156A to slide along the caster axis 148A within the caster body 146A such that the first shoulder 158A engages the rim 160A and thus prevents the front wheel 14A from spinning about the caster axis 148A. Advantageously, the front suspension assembly 140 A can prevent the front wheel 14A from freely spinning about the caster axis 148A when the front wheel 14 loses contact with the ground. Thus, the front suspension assembly 140 A may avoid the front wheel 14A from regaining contact with the ground surface in a position that is incompatible with the current direction of travel of the ZTR 10, which may otherwise exert vibrations and torsional stresses on the suspension system 100.

[0077] As shown in FIGS. 1-3 and 5-7, the pivoting motion of the rocker arm 110A around the pivot axis 104 is synchronized with pivoting motion of the rocker arm HOB, according to some embodiments. For example, the suspension system 100 may include a rocker differential 164. The rocker differential 164 may include a crank 168 that is coupled to the rocker arm 110A via connecting rod 170A and coupled to the rocker arm HOB via connecting rod 170B. The crank 168 may extend between a first end 172 and a second end 174. Thesecond end 174 may be 180 degrees out of phase relative to the first end 172. When the rocker arm 110A pivots about the pivot axis 104, the connecting rod 170A may drive the first end 172 of the crank 168 to pivot about the crank pivot axis 54, which causes the second end 174 to pivot about the crank pivot axis 54 out of phase, and the connecting rod 170B may transfer the pivot motion to the rocker arm HOB. For example, if the rocker arm 110A pivots clockwise around the pivot axis, the crank 168 may pivot about the crank pivot axis 54 such that the rocker arm HOB pivots counterclockwise around the pivot axis.

[0078] In some embodiments, the crank 168 is configured to pivot about the crank pivot axis 54 within a limited angular range (e.g., ±7 degrees). For example, the crank 168 may pivot around the crank pivot axis 54 within the spaces between the cage arms 64. In some embodiments, the crank 168 may include a damper that resists angular velocity of the crank 168 around the crank pivot axis 54, and in turn, dampens the pivoting motions of the rocker arms 110A, 110B about the pivot axis 104. In some embodiments, the distance between the first end 172 and the crank pivot axis 54 is the same as the distance between the second end 174 and the crank pivot axis 54. In some embodiments, the first end 172 is coupled to a first end of the connecting rod 170 A, and the second end of the connecting rod 170 A is pivotally coupled to the rocker arm 110A at a joint 173 A. In some embodiments, the distance between the first end 172 and the second end 174 of the crank 168 is approximately the same as the distance between the rocker arm 110A and the rocker arm 110B. For example, the distance between the first end 172 and the symmetry plane 102 may be the same as or similar to the distance between the pivot 112A and the symmetry plane 102. For example, the connecting rod 170A may extend along a longitudinal axis that is parallel to the symmetry plane 102. In some embodiments, the longitudinal axis of the connecting rod 170A is parallel to the symmetry plane 102 when the longitudinal axis of the crank 168 is perpendicular to the symmetry plane. In some embodiments, the connecting rod 170A is pivotally coupled to the rocker arm 110A at the joint 173A and the pivot axis of the joint 173A is above the pivot axis 104.

[0079] FIG. 6 illustrates a kinematic diagram (i.e., skeleton diagram) of the rocker differential 164, according to some embodiments. The motion of the rocker differential 164 relative to the chassis 12 is similar to an offset crank slider linkage. The angular motion of the crank 168 around the crank pivot axis 54 drives a sliding motion of the second end of the connecting rods 170A, 170B at joints 173 A and 173B, respectively.

[0080] In FIGS. 6 and 7, the kinematic diagrams are illustrated and described with reference to a Cartesian coordinate system having the dimensions of X, Y, and Z and an origin arbitrarily placed along the pivot axis 104. The Z dimension is the pivot axis 104, the X dimension is parallel to a level ground surface, the Y dimension is orthogonal to the X and Z dimensions.

[0081] In FIGS. 6 and 7, the joint 173 A is spaced from the pivot 112A by a distance “a.” The joint 173A is spaced from a first end of the shock absorber 124A by a distance “n.” The joint 173A is spaced from a first end of the shock absorber 150A by a distance “b ” The first end of the shock absorber 150 A is spaced from the first end of the link 142 A by a distance “c ” The first end of the link 142A is spaced from the first end of the link 144A by a distance “d ” The first end of the link 144A is spaced from the pivot 112A by a distance “e ” The first end of the shock absorber 150A is spaced from the second end of the shock absorber 150A by a distance “f.” The first end of the link 142A is spaced from the second end of the link 142A by a distance “g.” The first end of the link 144A is spaced from the second end of the link 144A by a distance “h.” The second end of the link 142A is spaced from the second end of the shock absorber 150A by a distance “i.” The second end of the link 142A is spaced from a second end of the link 144A by a distance “j.” the second end of the link 144A is spaced from the second end of the shock absorber 150A by a distance “k.” The second end of the link 144A is spaced from the front wheel axis 152A by a distance “L.” The pivot 112A is spaced from the rear pivot axis 122A by a distance “m.” The joint 173A is spaced from the first end of the shock absorber 124A by a distance “n.” The first end of the shock absorber 124A is spaced from the rear pivot axis 122A by a distance “o ” The rear pivot axis 122A is spaced from the second end of the shock absorber 124A by a distance “p.” The second end of the shock absorber 124A by a distance “q.” The pivot 112A is spaced from the rear wheel rotation axis 136A by a distance “r.” The rear wheel rotation axis 136A is spaced from the second end of the shock absorber 124A by a distance “s ” The first end of the connecting rod 170A is spaced from the second end of the connecting rod 170A by a distance “t ” The first end 172 of the crank 168 is spaced from the crank pivot axis 54 by a distance “u ” The second end 174 of the crank 168 is spaced from the crank pivot axis 54 by a distance “u* ” The first end of the connecting rod 170B is spaced from the second end of the connecting rod 170B by a distance “t* ”

[0082] In some embodiments, the distances a, b, c, e, f, g, h, i, j, k, 1, m, n, o, p, r, s, t, and / or u may be fixed values (e.g., static values). The distances f, g, may be transient (e.g., dynamic, etc.). In some embodiments, the distance L is transient. In some embodiments, the distance e is larger than the distance m. In some embodiments, the distance d is the same as the distance ). In some embodiments, the distance d is taken in a direction being parallel to the direction of the distance), and / or the axis Y. In some embodiments, the distance u* is the same as the distance u. In some embodiments, the distance t* is the same as the distance t.

[0083] In some embodiments, the joint 173A travels (e.g., translates and / or pivots, etc.) in an XY plane. In some embodiments, the second end 172 of the crank 168 travels in an XZ plane. In some embodiments, the suspension cradle 126A, rear shock absorber 124A, pivot arm 110A, links 142A 144A, front shock absorber 150A, and caster body 146A travel in an XY plane.

[0084] In some embodiments, the rocker arm 110A is stationary relative to the chassis 12 when the torques around the pivot axis 104 attributed to the front wheel ground force F wheell and the rear wheel ground force F wheel2 are equal and opposite. In some embodiments, the rocker arm 110A and the rocker arm HOB are stationary relative to the chassis when the torques around the pivot axis 104 are balanced. For example, when the torque of F wheell exceeds the torque of F_wheel2, the excess energy, shown as force F side may be transferred to the rocker arm HOB via the differential 164 which can communicate torque on the rocker arm 110B. The torque on the rocker arm 110B may be absorbed by the shock absorbers 124B, 150B. In some embodiments, the force F side includes one or more biasing forces of the differential 164 configured to dampen and / or regulate motion transfer between the rocker arm 110A and the rocker arm 110B.

[0085] In some embodiments, when the front wheel 14A and the rear wheel 16A pivot about the pivot axis 104 in a first direction (e.g., clockwise), the front wheel 14B and the rear wheel 16B pivot about the pivot axis 104 in a second direction opposite the first direction (e.g., counterclockwise). In some embodiments, when the front wheel 14A and the rear wheel 16A pivot about the pivot axis 104 in a first direction, the rocker arm 110B pivots about the pivot axis 104 in a second direction opposite the first direction and the front wheel 14B and the rear wheel 16B remain stationary relative to the pivot axis 104. That is, the rotation ofthe rocker arm HOB in the second direction is absorbed by the rear shock absorber 124B and / or the front shock absorber 15 OB.

[0086] As shown in FIG. 12, the rear frame 44 of the chassis 12 may be a cantilever, according to some embodiments. The rear frame 44 may support loads applied to the rocker differential 164. For example, the rear frame 44 may anchor the crank 168 relative to the chassis 12. The rear frame 44 may support the accessory 28. For example, the bottom side of the rear frame 44 may include a pair of mounting rails 180 (e.g., channels, grooves, c- channels, etc.) that slidably engage corresponding rails and / or other mounting features provided by the accessory 28. The mounting rails 180 may be flared at a rear end, such that the ZTR 10 may drive in the direction of the flared opening (e.g., backward), which capture a corresponding rail insert of the accessory 28. In some embodiments, the mounting rails 180 include electrodes that electrically couple the accessory to the electrical system of the ZTR 10. For example, the battery assembly 22 may power the accessory 28. As another example, the accessory 28 may power the ZTR 10, or supplement the power supplied by the battery assembly 22. For example, the accessory 28 may have a 35-45 kilo-watt hour (kWh) capacity. The battery assembly 22 may have a lesser capacity than the accessory 28. For example, the battery assembly 22 may have approximately a 3.5 kWh capacity. The battery assembly 22 may provide power to the independent electric motor assemblies 300 A, 300B and the control systems of the ZTR 10 while a battery type accessory 28 is depleted or not coupled to the ZTR 10. In some embodiments, the battery assembly 22 provides a reserve charge configured to enable the ZTR 10 to travel a predetermined distance that allows the ZTR to travel toward a charging station and / or a location of a charged battery type accessory 28. Advantageously, the ZTR 10 may be driven into engagement with the accessory 28, which may permit a user to avoid manually lifting or transporting the accessory 28. For example, an accessory 28 may be a battery pack type accessory 28 and can weigh in excess of 50 pounds. The suspension system 100 may kneel to align the rails 180 with the rails of the accessory 28 and subsequent to the accessory 28 being coupled to the rails 180, the suspension system 100 may return to a non-kneeling home position.

[0087] In some embodiments, the accessory 28 is configured to be placed on a track, placed on a sliding shelf. In some embodiments, the accessory 28 includes a four-bar link for a gurney to extend a pair of wheels to roll the accessory 28 along a surface to facilitate mounting or dismounting the accessory 28 from the mounting rails 180. In someembodiments, the accessory 28 includes a ledge that engages the core frame 46 to position the bottom of the accessory 28. For example, the accessory 28 and / or the core frame 46 may include one or more guide rods.

[0088] In some embodiments, the accessory 28 includes a bank of small swappable battery packs. For example, the accessory 28 may include an array of 6, 7, or 8 small swappable battery packs that are independently swappable relative to one another.

[0089] In some embodiments, the rear frame 44 is a cantilevered platform creating an accessory space 182 defined below the rear frame 44, above the independent electric motor assemblies 300A and 300B, and rear wheel rotation axis 136A. In some embodiments, the accessory 28 and / or the battery assembly 22 are supported by the chassis 12 between the independent electric motor assemblies 300 A, 300B. For example, a motor gap 184 may be defined between the motor body 302 A and the motor body 302B. As shown, the motor gap 184 is 14 inches. In some embodiments, the motor gap 184 is between 10 inches and 14 inches. The accessory 28 may be coupled to the mounting rails 180 such that the accessory 28 is within the accessory space 182 and the motor gap 184.

[0090] In some embodiments, the deck assembly 18 defines one or more blade wells 190 (e.g., cutting chambers). The blade wells 190 may be dome shaped. The blade wells 190 may define an internal volume 192. For example, the blade well 190 may define a fluid conduit between an inlet 194 and an outlet 196. The inlet 194 may be encircled by a sidewall 198. In some embodiments, the blade wells 190 are fluidly separate from adjacent blade wells 190 of the mower deck assembly 18. For example, air and debris that enter an inlet 194 exits through the corresponding outlet 196 of the respective blade well 190. For example, a mower deck assembly 18 may have three blade wells 190, and the first inlet is fluidly coupled to the first outlet but not the second outlet or the third outlet. In other words, the mower deck assembly 18 may define a fluidly separate flow path for each blade well 190. Fluidly separate flow paths can improve cut performance by generating a consistent pressure profile across the inlet 194 for each blade well 190 of the mower deck assembly 18. For example, the pressure within a first internal volume 192 is not communicated to other internal volumes 192 of the mower deck assembly 18.

[0091] In some embodiments, a rotary implement 200 (e.g., blade, blower, lawnmower blade, propeller-type mower blade, etc.) may be coupled to an implement motor 202configured to rotate the rotary implement 200 within the internal volume 192 and around a blade axis 204. In some embodiments, the rotation of the rotary implement 200 about the blade axis 204 draws a flow of air and debris into the inlet 194, through the internal volume 192, and expels the air and debris through the outlet 196. In some embodiments, air and debris are directed (e.g., drafted, sucked, compelled, impelled, propelled, etc.) in an upward direction AA through the inlet 194, then in a rearward direction BB within the internal volume 192, and then in a downward direction CC through the outlet 196. In some embodiments, the upward direction AA is parallel and opposite to the downward direction CC. In some embodiments, the rearward direction BB is perpendicular to the upward direction AA and / or the downward direction CC. In some embodiments, air and debris are directed upward AA through the inlet 194 and travel past the implement motor 202 while traveling in the upward direction AA, then are directed in the rearward direction BB and travel through a space 195 above the top surface of the implement motor 202 while traveling in the rearward direction BB within the internal volume 192, then are directed in a downward direction CC through the outlet 196.

[0092] In some embodiments, operation of the mower deck assembly draws 60% to 80% of the power demanded during operation of the ZTR 10. Unexpectedly, the mower deck assembly 18 improves electrical efficiency by 80%. In other words, the mower deck assembly 18 operates at 20% of the power of a conventional mower deck of a comparable size (e.g., cutting width, number of blades, etc.). The blade wells 190 provide a shorter path downstream of the cutting blades to a discharge port. Additionally, air and debris can be directed downward through the outlet 196, which may direct the debris and grass clippings downward toward the roots of the cut grass. The downward discharge through the outlet 196 may prevent the grass clippings from bunching on the top surface of the cut grass (e.g., as may be common with a side-discharge mower deck). Bunching on the top surface of the cut grass can be unsightly (e.g., as the grass clippings turn brown) and / or shade the cut grass underneath the bunched grass clippings. Advantageously, the mower deck assembly 18 addresses the aforementioned technical problem in the technical field of landscaping and chore equipment.

[0093] As shown in FIGS. 15-18, the ZTR 10 may include deflection bars 210 (e.g., antiscalp bars, bumpers, etc.). The deflection bars 210 may be coupled to the mower deck assembly 18. The deflection bars may support deck wheels 212 (see, e.g., FIG. 16). Thedeck wheels 212 may act like rollers. The deck wheels 212 may carry a portion of the weight of the mower deck assembly 18 along the ground surface. The ZTR 10 may include two deflection bars 210. The deflection bars 210 may be coupled to two deck wheels 212. The deck wheels 212 may have a large diameter such that the deck wheels 212 can traverse changes in terrain such as bumps and rocks. The deflection bars 210 may span between the front end of the mower deck assembly 18 and the rear end of the mower deck assembly 18. The deflection bars 210 may span underneath a portion of the inlet 194 of a blade well 190. The deflection bars 210 may be height adjustable relative to the bottom of the mower deck assembly 18. In some embodiments, the defection bars 210 may be u-shaped. In some embodiments, caster wheels may be coupled to the bottom of the deflection bar 210.

[0094] In some embodiments, the mower deck assembly 18 is coupled to the links 144A, 144B. For example, the motion of the front edge of the inlets 194 of the mower deck assembly 18 relative to the chassis 12 may follow the motion of a portion of the 144A, 144B. For example, the front edge of the mower deck assembly 18 may follow the front wheels 14. For example, the front wheel 14A may vertically translate 1 inch along the caster axis 148A and at least a portion of the front edge of the mower deck assembly 18 may translate similarly. In some embodiments, the front wheels 14 may vertically translate along the caster axes 148A, 148B approximately 4 inches.

[0095] In some embodiments, the mower deck assembly 18 is coupled to the rear suspension cradles 126 A, 126B. For example, the motion of the rear edges of the inlets 194 of the mower deck assembly 18 relative to the chassis 12 may follow the motion of a portion of the rear suspension cradles 126 A, 126B. For example, the rear edge of the mower deck assembly 18 may follow the rear wheels 16. For example, the rear wheel 16A may travel 1 inch around the pivot axis 104, and the rear edge of the mower deck assembly 18 may travel similarly.

[0096] In some embodiments, the mower deck assembly 18 is coupled to the front ends 114A, 114B of the rocker arms 110A, HOB. In some embodiments, the mower deck assembly 18 is coupled to the rear ends 116A, 116B of the rocker arms 110A, HOB. In some embodiments, the mower deck assembly 18 is coupled to the chassis 12. In some embodiments, the mower deck assembly 18 is coupled to one or more of the rocker arms 110, links 144, rear suspension cradles 126, or chassis 12.

[0097] As shown in FIGS. 19-21, a rotary implement 200 includes a plate 220. The plate 220 may include an extruded hole 222. The extruded hole 222 may extend along a blade axis 224. The plate may include mounting apertures configured to facilitate coupling the plate 220 to the implement motor 202 about the blade axis 204. In some embodiments, the blade axis 224 is collinear with the blade axis 204. The rotary implement 200 may include one or more cutting blades 226 that extend radially around the blade axis 224. The cutting blades 226 may include a cutting edge 228 (e.g., a sharpened edge, a beveled edge, etc.). The cutting blades 226 may span between a first end 230 and a second end 232. The first end 230 may be coupled to the plate 220. The second end 232 may be coupled to a ring 234. The ring 234 may have a cylindrical shape, with the longitudinal axis being collinear with the blade axis 224. The ring 234 may improve the aerodynamic performance of the cutting blades 226. For example, the ring 234 may prevent the second ends 232 from inducing tip vortex cavitation that can contribute to aerodynamic drag. The ring 234 may direct air along the blade axis 224. In some embodiments, the rotary implement 200 includes three cutting blades 226. In some embodiments, the rotary implement 200 is configured to reduce back-pressure against the blade when rotated in the mower deck assembly 18, which reduces blade torque and improves efficiency.

[0098] As shown in FIG. 22, a rotary implement 240 defines a hole 242 that extends along a blade axis 244. In some embodiments, the rotary implement 240 may include some of the features and functions of the rotary implement 200. In some embodiments, the rotary implement 200 may include some or all of the features and functions of the rotary implement 240.

[0099] In some embodiments, the blade axis 244 is coaxial with the blade axis 204. The rotary implement 240 includes two cutting blades 246. The cutting blades 246 may define a first cutting edge 248 and a second cutting edge 250. In some embodiments, the rotary implement 240 is an airfoil shape and is configured to induce a draft of air and debris in the direction of the blade axis 244. In some embodiments, the pitch of the cutting blade 246 about the blade longitudinal axis 252 is relatively greater near the blade axis 244 than the distal end of the cutting blade 246.

[0100] As shown in FIG. 23, a pressure profile of a three-blade side-discharge mower deck is illustrated. Pressure variations are illustrated by variations in shading intensity. As shownin FIG. 24, a pressure profile of a two-blade rear-discharge mower deck is illustrated. The pressure variations are illustrated by shading intensity. The pressure profile associated with each blade varies between the blades of the illustrated mower decks.

[0101] In some embodiments, a suspension system includes a first rocker arm pivotally coupled to a first side of a chassis and configured to pivot about a first pivot axis, the first rocker arm spanning between a first end and a second end; a second rocker arm pivotally coupled to a second side of the chassis and configured to pivot about the first pivot axis, the second rocker arm spanning between a third end and a fourth end; a front suspension assembly coupled to the first end and pivotally supporting a wheel; and a rear suspension assembly coupled to the second end, the rear suspension assembly pivotally supporting a drive wheel.

[0102] In some embodiments, the rear suspension assembly includes a rear suspension cradle pivotally coupled to the second end and configured to rotate about a rear pivot axis, wherein an electric motor is coupled to the rear suspension cradle, and wherein the drive wheel is coupled to the rear suspension cradle.

[0103] Using the above-provided description, a ZTR 10 can be operated in an improved manner that provides a comfortable operator riding experience without sacrificing cut quality. The suspension system provides a smoother ride that transmits less force through the seat of the ZTR 10, which in turn reduces the amount of force passed through to the operator seated on the ZTR 10. The high precision provided by electric traction motors can enable the ZTR 10 to perform tight maneuvers to address different obstacles in a lawn, while also allowing for customization and optimization to configure the ZTR 10 for specific mowing tasks. The rotatable mounting of the pivot arms, and thus the front suspension assembly and the rear suspension assembly, and the rotatable mounting of each of the wheels of the ZTR can also prevent or limit wobble of the rear drive wheels relative to the chassis 12.

[0104] As utilized herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean + / - 10% of the disclosed values. When the terms “approximately,” “about,” “substantially,” and similar terms are applied to a structural feature (e.g., to describe its shape, size, orientation, direction, etc.), these terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subjectmatter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

[0105] It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

[0106] The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

[0107] References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

[0108] The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, particular processes and methods may be performed by circuitry that is specific to a given function. The memory (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and / or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory may be or include volatile memory or non-volatile memory, and may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. According to an exemplary embodiment, the memory is communicably connected to the processor via a processing circuit and includes computer code for executing (e.g., by the processing circuit or the processor) the one or more processes described herein.

[0109] The present disclosure contemplates methods, systems, and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure may be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures, and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scopeof machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

[0110] Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

[0111] It is important to note that the construction and arrangement of the suspension system 100 as shown in the various exemplary embodiments is illustrative only. Although only one example of an element from one embodiment that can be incorporated or utilized in another embodiment has been described above, it should be appreciated that other elements of the various embodiments may be incorporated or utilized with any of the other embodiments disclosed herein.

Claims

WHAT IS CLAIMED IS:

1. A zero-turn radius lawnmower comprising: a chassis; a mower deck assembly supported by the chassis; a wheel; a drive wheel; and a suspension system coupled to the chassis, the suspension system including: a first rocker arm pivotally coupled to a first side of the chassis and configured to pivot about a first pivot axis, the first rocker arm spanning between a first end and a second end; a front suspension assembly coupled to the first end and pivotally supporting the wheel; a rear suspension assembly coupled to the second end, the rear suspension assembly pivotally supporting the drive wheel.

2. The zero-turn radius lawnmower of claim 1, wherein the suspension system further comprises: a second rocker arm pivotally coupled to a second side of the chassis and configured to pivot about the first pivot axis, the second rocker arm spanning between a third end and a fourth end; and a crank pivotally coupled to the chassis and spanning between a first crank end and a second crank end; wherein the first crank end is coupled to the first rocker arm via a first connecting rod; and wherein the second crank end is coupled to the second rocker arm via a second connecting rod.

3. The zero-turn radius lawnmower of claim 2, wherein the crank is configured to pivot about a crank pivot axis, and wherein the crank pivot axis is perpendicular to the first pivot axis.

4. The zero-turn radius lawnmower of claim 1, wherein the rear suspension assembly includes a rear suspension cradle, and wherein the rear suspension cradle is pivotally coupled to the second end and is configured to pivot about a rear pivot axis.

5. The zero-turn radius lawnmower of claim 4, wherein the rear pivot axis is parallel to the first pivot axis.

6. The zero-turn radius lawnmower of claim 1, wherein the front suspension assembly includes a parallel linkage, and wherein the parallel linkage is configured to permit the wheel to translate relative to the first end.

7. The zero-turn radius lawnmower of claim 1, wherein the front suspension assembly includes a caster fork configured to rotate about a caster axis.

8. The zero-turn radius lawnmower of claim 7, wherein the front suspension assembly includes a caster body, wherein the caster fork is configured to slide within the caster body, and wherein when the wheel is suspended above a ground surface the caster fork slides within the caster body and the caster body engages the caster fork so that the caster fork is prevented from rotating about the caster axis.

9. The zero-turn radius lawnmower of claim 1, wherein the mower deck assembly includes: a blade well defining an internal volume and having an inlet and an outlet; a rotary implement; and an implement motor configured to rotate the rotary implement around a second axis; wherein when the rotary implement is rotated around the second axis, air and debris are directed in a first direction through the inlet and are directed in an opposite direction through the outlet.

10. The zero-turn radius lawnmower of claim 9, wherein the outlet is rearward of the inlet.

11. The zero-turn radius lawnmower of claim 9, wherein the blade well is a first blade well, and wherein the internal volume is a first internal volume; wherein the mower deck assembly further includes a second blade well defining a second internal volume, and wherein the second internal volume is fluidly separate from the first internal volume.

12. The zero-turn radius lawnmower of claim 9, wherein the air and debris travel within the internal volume above the implement motor.

13. The zero-turn radius lawnmower of claim 1, further comprising an operator seat coupled to the chassis; wherein the chassis includes a rear frame, and wherein the suspension system includes a crank pivotally coupled to the rear frame, the crank configured to pivot around a crank pivot axis.

14. The zero-turn radius lawnmower of claim 13, wherein the operator seat is coupled to the chassis between the first pivot axis and the crank pivot axis.

15. The zero-turn radius lawnmower of claim 1, further comprising a battery assembly supported by the chassis.

16. The zero-turn radius lawnmower of claim 15, further comprising an operator seat coupled to the chassis, wherein the battery assembly is coupled to the chassis below the operator seat.

17. The zero-turn radius lawnmower of claim 1, further comprising a mounting rail coupled to a rear frame of the chassis, the mounting rail configured to couple an accessory to the chassis.

18. The zero-turn radius lawnmower of claim 17, wherein the suspension system comprises a crank pivotally coupled to the rear frame.

19. The zero-turn radius lawnmower of claim 1, further comprising a pin, wherein the chassis comprises a hole configured to receive the pin, and wherein the pin is configured to selectively engage the first rocker arm and the chassis to prevent the first rocker arm from pivoting relative to the chassis.

20. The zero-turn radius lawnmower of claim 1, further comprising a battery pack coupled to the chassis in a space defined between the mower deck assembly and the chassis.

21. A zero-turn radius lawnmower comprising: a chassis; a mower deck assembly supported by the chassis; and a suspension system coupled to the chassis, the suspension system including: a first rocker arm pivotally coupled to a first side of the chassis and configured to pivot about a first pivot axis, the first rocker arm spanning between a front end and a rear end, wherein the first pivot axis intersects the first rocker arm between the front end and the rear end; a second rocker arm pivotally coupled to a second side of the chassis and configured to pivot about the first pivot axis; a rocker differential coupled to the first rocker arm and the second rocker arm, wherein the rocker differential includes a crank that is pivotally coupled to the chassis and configured to pivot about a crank pivot axis that is perpendicular to the first pivot axis.

22. The zero-turn radius lawnmower of claim 21, wherein the suspension system further comprises a first connecting rod extending between a first crank end of the crank and the first rocker arm, and a second connecting rod extending between a second crank end of the crank and the second rocker arm.

23. The zero-turn radius lawnmower of claim 21, wherein the suspension system further comprises a rear suspension assembly that includes a first rear suspension cradle pivotally coupled to the rear end of the first rocker arm, and a second rear suspension cradle pivotally coupled to a rear end of the second rocker arm.

24. The zero-turn radius lawnmower of claim 23, wherein each of the first rear suspension cradle and the second rear suspension cradle is coupled to an electric drive motor.

25. The zero-turn radius lawnmower of claim 21, wherein the suspension system further comprises a front suspension assembly that includes a first parallel linkage pivotally coupled between the front end of the first rocker arm and a first caster wheel assembly, and a second parallel linkage pivotally coupled between a front end of the second rocker arm and a second caster wheel assembly.

26. The zero-turn radius lawnmower of claim 25, wherein each of the first caster wheel assembly and the second caster wheel assembly includes a caster fork configured to rotate about a caster axis and slidably received within a caster body so that engagement between the caster fork and the caster body prevent rotation of a caster wheel about the caster axis.

27. The zero-turn radius lawnmower of claim 21, wherein the mower deck assembly includes: a blade well defining an internal volume and having an inlet and an outlet; a rotary implement; and an implement motor configured to rotate the rotary implement around a second axis; wherein when the rotary implement is rotated around the second axis, air and debris are directed in a first direction through the inlet and are directed in an opposite direction through the outlet.

28. The zero-turn radius lawnmower of claim 27, wherein the outlet is rearward of the inlet.

29. The zero-turn radius lawnmower of claim 27, wherein the blade well is a first blade well, and wherein the internal volume is a first internal volume, wherein the mower deck assembly further includes a second blade well defining a second internal volume, and wherein the second internal volume is fluidly separate from the first internal volume.

30. The zero-turn radius lawnmower of claim 29, wherein the air and debris travel within the internal volume above the implement motor.

31. The zero-turn radius lawnmower of claim 21, further comprising an operator seat supported on the chassis, and wherein the operator seat is arranged between the first pivot axis and the crank pivot axis.

32. The zero-turn radius lawnmower of claim 21, further comprising a battery assembly supported by the chassis, wherein the battery assembly is arranged laterally between the first rocker arm and the second rocker arm.

33. The zero-turn radius lawnmower of claim 32, further comprising an operator seat supported on the chassis, wherein the battery assembly is coupled to the chassis below the operator seat.

34. The zero-turn radius lawnmower of claim 21, further comprising a pin, wherein the chassis includes a hole configured to receive the pin, and wherein the pin is configured to selectively engage the first rocker arm and the chassis to prevent the first rocker arm from pivoting relative to the chassis.

35. A zero-turn radius lawnmower comprising: a chassis; a battery supported on the chassis; a mower deck assembly supported by the chassis; a caster wheel; a drive wheel; an electric drive motor powered by the battery and configured to drive the drive wheel; and a suspension system coupled to the chassis, the suspension system including: a first rocker arm pivotally coupled to a first side of the chassis and configured to pivot about a first pivot axis; a rear suspension assembly including a cradle that is pivotally coupled to a rear end of the first rocker arm, wherein the cradle at least partially receives the electric drive motor; a front suspension assembly pivotally coupled between the caster wheel and a front end of the first rocker arm, wherein the front suspension assembly includes a caster body and a caster fork that is coupled to the caster wheel, wherein the caster fork is slidably received within the caster body so that engagement between the caster fork and the caster body prevents rotation of the caster wheel about a caster axis.

36. The zero-turn radius lawnmower of claim 35, wherein the suspension system further comprises a second rocker arm pivotally coupled to a second side of the chassis and configured to pivot about the first pivot axis.

37. The zero-turn radius lawnmower of claim 36, wherein the suspension system further comprises a rocker differential coupled to the first rocker arm and the second rocker arm, wherein the rocker differential includes a crank that is pivotally coupled to the chassis and configured to pivot about a crank pivot axis that is perpendicular to the first pivot axis.

38. The zero-turn radius lawnmower of claim 37, wherein the suspension system further comprises a first connecting rod extending between a first crank end of the crank and the first rocker arm, and a second connecting rod extending between a second crank end of the crank and the second rocker arm.

39. The zero-turn radius lawnmower of claim 37, further comprising an operator seat supported on the chassis, and wherein the operator seat is arranged between the first pivot axis and the crank pivot axis.

40. The zero-turn radius lawnmower of claim 35, wherein the front suspension assembly includes a parallel linkage pivotally coupled between the caster wheel and the front end of the first rocker arm.

41. The zero-turn radius lawnmower of claim 35, wherein the mower deck assembly includes: a blade well defining an internal volume and having an inlet and an outlet; a rotary implement; and an implement motor configured to rotate the rotary implement around a second axis; wherein when the rotary implement is rotated around the second axis, air and debris are directed in a first direction through the inlet and are directed in an opposite direction through the outlet.

42. The zero-turn radius lawnmower of claim 41, wherein the outlet is rearward of the inlet.

43. The zero-turn radius lawnmower of claim 41, wherein the blade well is a first blade well, and wherein the internal volume is a first internal volume, wherein the mower deck assembly further includes a second blade well defining a second internal volume, and wherein the second internal volume is fluidly separate from the first internal volume.

44. The zero-turn radius lawnmower of claim 43, wherein the air and debris travel within the internal volume above the implement motor.

45. The zero-turn radius lawnmower of claim 36, wherein the battery is arranged laterally between the first rocker arm and the second rocker arm.

46. The zero-turn radius lawnmower of claim 45, further comprising an operator seat supported on the chassis, wherein the battery is coupled to the chassis below the operator seat.

47. The zero-turn radius lawnmower of claim 35, further comprising a pin, wherein the chassis includes a hole configured to receive the pin, and wherein the pin is configured to selectively engage the first rocker arm and the chassis to prevent the first rocker arm from pivoting relative to the chassis.

Images