Patent Publication Number: US-2021172142-A1

Title: Compaction machine with electric working assembly

Description:
TECHNICAL FIELD 
     Example embodiments generally relate to construction power equipment and, more particularly, relate to apparatuses associated with a drive for a compaction machine. 
     BACKGROUND 
     Compaction machines are commonly used on construction sites to compact soil or other aggregate (e.g., sand, rock, and the like) to form a solid, level surface that may be used, for example, to support a structural load. Many compaction machines operate by rapidly rotating an eccentric or imbalanced mass to create vibration that is translated to a lower plate that is in contact with the material to be compacted. Conventionally, such an imbalance mass is rotated by an internal combustion engine that generates exhaust and excessive heat. Further, in many implementations, the internal combustion engine must be protected from the vibration generated by the imbalance mass. As such, the internal combustion engine may be required to be seated on a separate, often upper surface, that is mechanically isolated from the imbalance mass and the vibrating plate. Due to this isolation, belts or other coupling mechanisms can be required to drive rotation of the imbalance mass, which adds to the mechanical complexity of the compaction machine and introduces additional maintenance requirements and failure points. As such, there is a need for improvements in the design and implementation of compaction machines that limit or eliminate some of the drawbacks of the conventional compaction machines described above. 
     BRIEF SUMMARY OF SOME EXAMPLES 
     According to some example embodiments, an example compaction machine is provided. The example compaction machine may comprise a compaction plate. The compaction plate may comprise a top surface and a bottom surface. The top surface may be on a side of the compaction plate opposite the bottom surface and the bottom surface may be a compacting surface. Further, the compacting machine may also comprise a housing disposed on the top surface of the compaction plate and an imbalance mass disposed within the housing and affixed to an imbalance mass shaft. The compacting machine may also comprise a first electric motor affixed to the housing and operably coupled to the imbalance mass shaft, and a second electric motor affixed to the housing and operably coupled to the imbalance mass shaft. The first electric motor and the second electric motor may be axially aligned along a shaft axis and affixed to the housing on opposite sides of the housing. 
     According to some example embodiments, another example compaction machine is provided. In this regard, the compacting machine may comprise a compaction plate and an imbalance mass assembly operably coupled to the compaction plate. In this regard, the imbalance mass assembly may comprise an imbalance mass shaft and an imbalance mass affixed to the imbalance mass shaft. The compacting machine may also comprise a first electric motor comprising a first electric motor shaft that is operably coupled to the imbalance mass shaft at a first end of the imbalance mass shaft, and a second electric motor comprising a second electric motor shaft that is operably coupled to the imbalance mass shaft at a second end of the imbalance mass shaft. The first end of the imbalance mass shaft may be disposed opposite the second end of the imbalance mass shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Having thus described some example embodiments in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG. 1  illustrates an example compaction machine according to an example embodiment; 
         FIG. 2  provides a top view of an example working assembly according to an example embodiment; 
         FIG. 3  provides a perspective front view of a front portion of a working assembly taken at A-A of  FIG. 2  according to an example embodiment; 
         FIG. 4  provides a top view of a front portion of a working assembly taken at A-A of  FIG. 2  according to an example embodiment; and 
         FIG. 5  illustrates internal components of a working assembly according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Some example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as being limiting as to the scope, applicability, or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. 
     As used herein the term “or” is used as the logical or where any one or more of the operands being true results in the statement being true. As used herein, the phrase “based on” as used in, for example, “A is based on B” indicates that B is a factor that determines A, but B is not necessarily the only factor that determines A. 
     According to some example embodiments, a compaction machine is provided that utilizes small-sized electric motors to drive an imbalance mass and generate vibration to perform, for example, soil compaction. In this regard, some example embodiments leverage the use of two cooperatively operating electric motors to rotate an imbalance mass disposed between the two electric motors. The electric motors may be mounted or affixed to ends of an imbalance mass housing that may be affixed to or integrated with a compaction plate. According to some example embodiments, the electric motors and a shaft of the imbalance mass may share a common axis of rotation. This axis of rotation for the shafts may be, for example, perpendicular to a longitudinal axis of the compaction plate, where the longitudinal axis of the compaction plate bisects the compaction plate from the front to the rear of the compaction plate. 
     The use of electric motors on a compaction machine realizes a number of benefits. For example, exhaust fumes are eliminated relative to an internal combustion engine-based solution. Further, heat generation can also be reduced due to use of the electric motors. This can be particularly true when, as mentioned above, two relatively small electric motors are used, which can reduce the heat generation even relative to a solution utilizing a single electric motor to drive an imbalance mass. Additionally, two relatively small electric motors can be used to implement a light-weight compaction machine that can be used, for example, in difficult to access locations or for projects where only “light” compaction is needed. For example, light compaction may be used for compacting soil in preparation for installing a paver walkway or for compacting aggregate prior to pouring cement for a side walk. 
     In this regard,  FIG. 1  illustrates a block diagram side view of an example compacting machine  10 , according to some example embodiments. In this regard, the compacting machine  10  may be comprised of a working assembly  100  and a control assembly  150 . The control assembly  150  may be configured to control the operation of the working assembly  100  via control circuitry  32  and user inputs via the user interface  44 . The working assembly may be configured to generate controlled vibratory motion of a compacting plate  20  to cause, for example, compaction of soil disposed beneath compacting plate  20 . 
     As such, the working assembly  100  may be a portion of the compacting machine  10  that is subjected to high-level vibration and may comprise a compacting plate  20 , an imbalance mass assembly  70 , a first electric motor  50 , and a second electric motor  60  (not shown in  FIG. 1 , but shown in  FIGS. 2-5 ). As further described below, the first electric motor  50  and the second electric motor  60  may be controlled to drive an imbalance mass within the imbalance mass assembly  70  to cause the compacting plate  20  to vibrate. The vibration of the compacting plate  20  may then be applied by a bottom surface and underlying soil or aggregate to perform a compaction operation. Further, according to some example embodiments, the first electric motor  50  and the second electric motor  60  may be the only electric motors of the compacting machine  10 . According to some example embodiments, an imbalance mass of the imbalance mass assembly  70  may be the only imbalance mass of the compacting machine  10 . 
     The compacting plate  20  may be an elongated plate formed of, for example, steel. The compacting plate  20  may be substantially planar and include at least a portion on a bottom surface  22  of the compacting plate  20  that is defined by a surface contacting plane  23 . As such, according to some example embodiments, the planar portion of the bottom surface  22  may be the portion of the compacting plate  20  that contacts the soil or aggregate beneath the compacting plate  20  during operation. According to some example embodiments, the bottom surface  22  of the compacting plate  20  may include other features such as rounded or arcuate edges (e.g., an arcuate front edge disposed near a front  90  of the compacting machine  10 ) to facilitate moving the compacting machine  10  onto loose soil or aggregate areas that require compaction. 
     A number of components may be operably coupled to a top surface  21  of the compacting plate  20 , where the top surface  21  is disposed on a side of the compacting plate  20  that is opposite the bottom surface  22 . In this regard, the first electric motor  50 , second electric motor  60 , and the imbalance mass assembly  70  may be operably coupled to the top surface  21  of the compacting plate  20 . According to some example embodiments, a housing  71  of the imbalance mass assembly  70  may be disposed on (e.g., affixed to) the top surface  21  of the compacting plate  20 . In this regard, according to some example embodiments, the housing  71  may be integrated (e.g., molded) into the compacting plate  20  such that the compacting plate  20  and the housing  71  are a single unitary component. However, according to some example embodiments, the imbalance mass housing  71  may be comprised of a number of component (e.g., a housing cover and a portion of the compacting plate  20 ) and the components may be affixed to each other via, for example, welding or fasteners (e.g., bolts and nuts, or the like). An imbalance mass  78  affixed to an imbalance mass shaft  72  may be disposed within the housing  71  and, more specifically, within a channel  75  of  FIG. 2 , open at both ends, of the imbalance mass housing  71 . The first electric motor  50  and the second electric motor  60  may be affixed to the housing  71 , for example, at open ends of the imbalance mass housing  71  as further described below. As such, according to some example embodiments, the first electric motor  50  and the second electric motor  60  may be operably coupled to the compacting plate  20  via the imbalance mass housing  71 . 
     According to some example embodiments, the first electric motor  50  and the second electric motor  60  may be identical, but installed on opposite sides of the imbalance mass housing  71 . In this regard, the first electric motor  50  and the second electric motor  60  may have the same voltage and the mechanical output ratings. Example electric motors that may be included may, for example, be rated 380 Watts or 600 Watts (or a range there between), and because two motors may be utilized, such wattage may be doubled to indicate the full power rating of the motor system (i.e., 760 Watts and 1200 Watts, respectively). According to some example embodiments, the first electric motor  50  and the second electric motor  60  may be brushless motors, brushless direct current (BLDC) motors, brushed direct current (DC) motors, brushed alternating current (AC) motors, switched reluctance (SR) motors, or asynchronous motors. According to some example embodiments, the first electric motor  50  and the second electric motor  60  may be sized to operate together in collaboration to drive the imbalance mass of the imbalance mass assembly  70 . According to some example embodiments, the first electric motor  50  and the second electric motor  60  may be sized such that the first electric motor  50  or the second electric motor  60  alone would not provide sufficient mechanical torque to drive the imbalance mass assembly  70 . In this regard, for example, a torque output of the first electric motor  50  may be insufficient to rotate the imbalance mass without contribution from the second electric motor  60 . As such, the first electric motor  50  and the second electric motor  60  may be relatively small electric motors that weigh less and generate less heat and other emissions, while still being capable of driving the imbalance mass assembly  70 . The first electric motor  50  may comprise a first electric motor housing  54  and the second electric motor  60  may comprise a second electric motor housing  64  (not shown in  FIG. 1 , but shown in  FIGS. 2-4 ). 
     As mentioned above, the control assembly  150  may be configured to control the operation of the working assembly  100 . Additionally, the control assembly  150  may include more sensitive components that can, but need not be, subjected to high-level vibration. As such, an upper platform  30  of the compacting machine  10 , that structurally supports the components of the control assembly  150 , may be operatively coupled to the compacting plate  20  via dampening supports  40 . The dampening supports  40  may be formed of rubber or spring-based dampening materials to reduce or eliminate the transmission of the vibration generated by the working assembly  100  to the control assembly  150 . As such, according to some example embodiments, the dampening supports  40  may be stand-offs that support the upper platform  30  above the compacting plate  20  and dampen the vibrations of the compacting plate  20 . 
     The control assembly  150  may therefore comprise the upper platform  30 , control circuitry  32 , a power storage device  34 , a coupler  36 , a steering handle  42 , a user interface  44 , a power cable  46 , and a power plug  48 . According to some example embodiments, the control circuitry  32 , the power storage device  34 , and the coupler  36  may be affixed to the upper platform  30  of the control assembly  150 . The coupler  36  may be configured to mechanically affix the steering handle  42  to the upper platform  30  near the rear  92  of the compacting machine  10 . The steering handle  42  may be configured to permit a user to grasp the steering handle  42  and control the movement of the compacting machine  10 . Because the steering handle  42  is affixed to the upper platform  30 , vibration from the working assembly  100  may be reduced in the steering handle  42  by the dampening supports  40 . Additionally, according to some example embodiments, the coupler  36  may include additional mechanical dampeners to further reduce vibration traveling to the steering handle  42  and thereby further decreasing the vibration experienced by the user via the steering handle  42 . 
     The control circuitry  32  may be operably coupled, from a mechanical perspective, to the upper platform  30  and may be electrically connected at least to the first electric motor  50  and the second electric motor  60 . According to some example embodiments, the control circuitry  32  may also be electrically connected to the power storage device  34 , the power cable  46 , and the user interface  44 . 
     The control circuitry  32  may, according to some example embodiments, include a processor and a memory that may be configured to support various functionalities of compacting machine  10  and the operation of the working assembly  100  described herein. The control circuitry  32  may also include other passive and active electronic components configured to support the operation of the control circuitry  32  as described herein. In some example embodiments, the processor of the control circuitry  32  may be configured to execute instructions stored in a memory to effectuate the functionality described herein. Alternatively, the processor may be hardware configured as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like configured to execute the functionality of the control circuitry  32  as described herein. 
     In this regard, the control circuitry  32  may be configured to control the operation of the first electric motor  50  and the second electric motor  60 . The control circuitry  32  may control the voltage provided to the first electric motor  50  and the second electric motor  60 . According to some example embodiments, controlling the voltage to the first electric motor  50  and the second electric motor  60  may be a binary operation that applies a threshold voltage to the first electric motor  50  and the second electric motor  60  when the compacting machine  10  is “on” and does not apply a threshold voltage when the compacting machine  10  is “off” According to some example embodiments, the control circuitry  32  may also be configured to control a speed or rotations per minute (RPM) of the first electric motor  50  and the second electric motor  60 . In some example embodiments, the control circuitry  32  may be configured to control the first electric motor  50  and the second electric motor  60  to have a common rotational speed. The speed of the first electric motor  50  and the second electric motor  60  may control a frequency of the vibration generated by the working assembly  100 . In this regard, depending on a type of soil or aggregate being compacted, certain frequencies of vibration may be more effective for compaction purposes. 
     The control circuitry  32  may be connected to the user interface  44 , which may comprise one or more user controls such as switches, knobs, or the like. According to some example embodiments, the user interface  44  may be disposed on the steering handle  42  to facilitate convenient interaction by the user. In this regard, the user interface  44  may be configured to receive inputs from a user and convert those inputs into an electrical signal for provision to the control circuitry  32 . For example, the user interface  44  may include an on/off switch that, when actuated by the user, causes the first electric motor  50  and the second electric motor  60  to receive or discontinue receiving a voltage. Further, the user interface  44  may include other controls, such as a knob, configured to send a signal to the control circuitry  32  to control a vibration frequency of the working assembly  100 . While depicting in  FIG. 1  as being disposed on the steering handle  42 , the user interface  44  may be disposed, for example, elsewhere on the control assembly  150 , such as on the control circuitry  32 . 
     The control circuitry  32  may be configured to operate the first electric motor  50  and the second electric motor  60  identically. In this regard, the signals or voltages that are provided to the first electric motor  50  may be the same or identical signals to the those provided to the second electric motor  60 . For example, that control circuitry  32  may be electrically connected to the first electric motor  50  and the second electric motor  60  in parallel. As such, the voltages or signals provided to the first electric motor  50  may be the same as those provide to the second electric motor  60 . 
     According to some example embodiments, electrical power may be supplied to the first electric motor  50  and the second electric motor  60 , as well as the control circuitry  32 , via the power cable  46 . In this regard, the power plug  48  disposed at an end of the power cable  46  may be coupled to mains power to supply power the compacting machine  10 . The control assembly  150  may include power regulators and conditioning components configured to supply electrical energy to the first electric motor  50 , the second electric motor  60 , and the control circuitry  32  in a form that supports the operation of the first electric motor  50 , the second electric motor  60 , and the control circuitry  32 . 
     The power storage device  34  may be configured to provide portable power to the first electric motor  50  and the second electric motor  60 . Additionally, the power storage device  34  may operate as a power source for the control circuitry  32 . As such, the first electric motor  50  and the second electric motor  60  may be at least partially powered by the power storage device  34 . The power storage device  34  may be a battery sized to store sufficient power to operate the compacting machine  10  for a desirable period of time for a project. The battery may be rechargeable, such as, for example, a lithium-ion or other technology battery. Further, to charge the battery, the control circuitry  32  may be configured to operate as a battery management system to monitor charging and discharging of the battery. The power cable  46 , when connected to mains power, may be utilized to provide a charging power source to the battery. 
       FIG. 2  illustrates a top view of the working assembly  100  with a partial transparent view into some components. In this regard, the compacting plate  20  is shown with the first electric motor  50 , second electric motor  60 , and the imbalance mass assembly  70 . A longitudinal axis  102  is defined along a plane of the compacting plate  20 . The longitudinal axis  102  is defined such that the longitudinal axis  102  bisects the compacting plate  20  into two equal portions thereby defining a longitudinal center of the compacting plate  20 . 
     As shown, in  FIGS. 1 and 2 , the first electric motor  50 , second electric motor  60 , and imbalance mass assembly  70  may be disposed towards a front  90  of compacting plate  20 . According to some example embodiments, the first electric motor  50 , second electric motor  60 , and imbalance mass assembly  70 , when considered as a unit, may be disposed centrally relative to the longitudinal axis  102 , such that the longitudinal axis  102  also bisects the imbalance mass assembly  70  and the unit comprising the first electric motor  50 , the second electric motor  60 , and the imbalance mass assembly  70 . 
     As shown in  FIG. 2 , the a first electric motor  50  may be affixed to the housing  71  and operably coupled to an imbalance mass shaft  72 . Similarly, a second electric motor  60  may be affixed to the housing  71  and operably coupled to the imbalance mass shaft  72 . More particularly, the first electric motor  50  may comprise a first electric motor shaft  51  and the second electric motor  60  may comprise a second electric motor shaft  61 . Further, the imbalance mass assembly  70  may comprise the imbalance mass shaft  72  coupled to an imbalance mass  78 . The first electric motor shaft  51  may be driven to rotate in a selected rotational direction by the first electric motor  50 . The second electric motor shaft  61  may be driven to also rotate in the selected rotational direction by the second electric motor  60 . The first electric motor shaft  51  may be operably coupled to the imbalance mass shaft  72  at a first end of the imbalance mass shaft  72  via a mechanical coupling  74 . The second electric motor shaft  61  may be operably coupled to the imbalance mass shaft  72  at a second, opposite end of the imbalance mass shaft  72  via a mechanical coupling  76 . 
     As such, according to some example embodiments, the first electric motor shaft  51 , the second electric motor shaft  61 , and the imbalance mass shaft  72  may define a common axis of rotation  101 , also referred to as the shaft axis. Further, the first electric motor shaft  51  may be rotationally fixed to the imbalance mass shaft  72  and the second electric motor shaft  61  may also be rotationally fixed to the imbalance mass shaft  72  such that the first electric motor shaft  51 , the second electric motor shaft  61 , and the imbalance mass shaft  72  rotate together. As such, according to some example embodiments, the first electric motor shaft  51  and the second electric motor shaft  61  may be axially aligned with respect to the axis of rotation  101 . Similarly, the first electric motor  50  and the second electric motor  60  may be axially aligned with respect to the axis of rotation  101 . Further, the imbalance mass shaft  72  may be axially aligned with the first electric motor shaft  51  and the second electric motor shaft  61  with respect to the axis of rotation  101 . The axis of rotation  101  may further be defined as being perpendicular to the longitudinal axis  102  of the compacting plate  20 . In other words, the first electric motor shaft  51  and the second electric motor shaft  61  may extend along the axis of rotation  101  transverse to a longitudinal axis  102  of the compaction plate  20 . Further, according to some example embodiments, the imbalance mass shaft  72  may also extend perpendicularly to the longitudinal axis  102  of the compaction plate  20 . According to some example embodiments, the axis of rotation  101  may be parallel to the plane  23  of the bottom surface  22  (i.e., the soil compacting surface) of the compacting plate  20 . 
     Further, to maintain a center of gravity on the longitudinal axis  102 , according to some example embodiments, the imbalance mass assembly  70  may be bilaterally symmetric about the longitudinal axis  102  with respect to structure and with respect to weight distribution. According to some example embodiments, the imbalance mass  78  itself may have bilateral symmetry about the longitudinal axis  102  with respect to weight distribution. According to some example embodiments, when considered as a unit, the first electric motor  50 , the second electric motor  60 , and the imbalance mass assembly  70  may together have bilateral symmetry about the longitudinal axis  102  with respect to structure and with respect to weight distribution. In this regard, the working assembly  100  may be constructed such that the center of gravity of the working assembly  100  is disposed at a point on the longitudinal axis  102 . Further, according to some example embodiments, the center of gravity of the entire compacting machine  10  may be disposed central to the compacting plate  20  because the weight of the upper platform  30  may be disposed toward the rear  92  of the compacting machine  10  and may balance with the weight of the first electric motor  50 , the second electric motor  60 , and the imbalance mass assembly  70 , which may be positioned closer to the front  90  of the compacting machine  10 . In some example embodiments, weights may be added to the design of the compacting machine  10  (e.g., weight may be added near the rear  92  of the compacting machine  10 ) to cause the center of gravity of the compacting machine  10  to be centrally located on the compacting plate  20 . A centrally located center of gravity allows for the compacting machine  10  to be more easily maneuverable by the user because the compacting machine  10  should remain relatively stationary while vibrating when the center of gravity is centrally located. 
     As mentioned above, the imbalance mass housing  71  may have a channel  75  which may be a pass-through opening in the imbalance mass housing  71 . The channel  75  may be sized to house the imbalance mass shaft  72  and the imbalance mass  78 , and permit the imbalance mass shaft  72  and imbalance mass  78  to rotate within the channel  75 . According to some example embodiments, the channel  75  may be cylindrical in shape. In this regard, the axis of rotation  101  may define a central axis through the channel  75 . 
       FIGS. 3 and 4  illustrate a portion of the working assembly  100  taken at A-A of  FIG. 2 . As shown in  FIGS. 3 and 4 , the imbalance mass assembly  71  may be integrated with the compacting plate  20 . Further, due to the first electric motor  50  being installed on a first side of the imbalance mass housing  71  and the second electric motor  60  being installed on a second side of the imbalance mass housing  71 , the openings in the ends of the channel  75  of the imbalance mass housing  71  may be covered by the first electric motor housing  54  and the second electric motor housing  64 . As can be seen, the first electric motor housing  54  and the second electric motor housing  64  are axially aligned with the axis of rotation  101 . 
     Further, with particular reference to  FIG. 3 , a portion of the bottom surface  22  of the compacting plate  20  may define a plane  23  for interacting with soil or aggregate. However, the compacting plate  20  may also include a curved or arcuate front portion  25  that extends out of and above the plane  23 . The curved shape of the front portion  25  may facilitate movement or maneuvering of the compacting machine  10  in a forward direction while maintaining the compacting machine  10  on top of or above the soil or aggregate, as opposed to digging into the soil or aggregate. 
     Now referencing  FIG. 5 , components of the first electric motor  50 , the second electric motor  60 , and the imbalance mass assembly  70 , of the working assembly  100 , that are disposed within the housings of the first electric motor  50 , the second electric motor  60 , and the imbalance mass assembly  70  are shown. In this regard, for reference, the components are shown relative to the axis of rotation  101  defined in  FIGS. 2-4 . 
     Internal components of the first electric motor  50  are shown, which may be housed in the first electric motor housing  54 . In this regard, the first electric motor  50  may comprise a motor shaft  51  that may be rotationally driven due to interaction between the motor stator  53  and the motor rotor  52 . Further, the motor rotor  52  may be disposed internal to the motor stator  53 . The first electric motor shaft  51  may be affixed to the motor rotor  52  to translate the rotation of the motor rotor  52  to the first electric motor shaft  51 . Additionally, the first electric motor shaft  51  may be mechanically coupled to the imbalance mass shaft  72  via a coupler  74 . 
     Internal components of the second electric motor  60  are also shown, which may be housed in the second electric motor housing  64 . In this regard, the second electric motor  60  may comprise a motor shaft  61  that may be rotationally driven due to interaction between the motor stator  63  and the motor rotor  62 . Further, the motor rotor  62  may be disposed internal to the motor stator  63 . The second electric motor shaft  61  may be affixed to the motor rotor  62  to translate the rotation of the motor rotor  62  to the second electric motor shaft  61 . Additionally, the second electric motor shaft  61  may be mechanically coupled to the imbalance mass shaft  72  via a coupler  76 . 
     As shown in  FIG. 5 , the imbalance mass assembly  70  may include an imbalance mass  78  affixed to an imbalance mass shaft  72 . In this regard, the imbalance mass  78  may be a heavy weight that is affixed to imbalance mass shaft  72  such that the weight distribution about the axis of rotation  101  is non-uniform. As a result of the non-uniform weight distribution, as the imbalance mass shaft  72  rotates, the imbalance mass  78  may create an acceleration and deceleration event each time the imbalance mass  78  performs a revolution due to the effect of gravity on the imbalance mass  78 . The acceleration and deceleration events may cause movement in the working assembly  100  thereby creating a vibration for use in compaction. The imbalance mass  78  may be formed of any type of material, such as, for example, iron or steel. According to some example embodiments, first electric motor shaft  51 , the second electric motor shaft  61 , and the imbalance mass shaft  72  may be affixed to each other or may be formed as a singular, unitary component. In this regard, being mechanically or operably coupled includes the options of being affixed to or integrated with as a singular unitary component. Further, the first electric motor shaft  51 , the second electric motor shaft  61 , and the imbalance mass shaft  72  may be operably coupled such that these components are rotationally fixed and therefor rotate together. Further, according to some example embodiments, the first electric motor shaft  51 , the second electric motor shaft  61 , or the imbalance mass shaft  72  may be operably coupled to bearings that facilitate smooth rotation of the shafts. For example, according to some example embodiments, bearings may be disposed on each side of the imbalance mass shaft  72 , disposed between the first electric motor  50  and the imbalance mass  78  and between the second electric motor  60  and the imbalance mass  78 . 
     Accordingly, as provided herein, an example compaction machine  10  is provided that may comprise a compaction plate  20 . The compaction plate  20  may comprise a top surface  21  and a bottom surface  22 . Further, the top surface  21  may be on a side of the compaction plate  20  opposite the bottom surface  22 . The bottom surface  22  may be a compacting surface for contacting soil or aggregate to compact. The example compacting machine  10  may also comprise a housing  71  disposed on the top surface  21  of the compaction plate  20 . The example compacting machine  10  may also comprise an imbalance mass  78  disposed within the housing  71  and affixed to an imbalance mass shaft  72 . The example compacting machine  10  may also comprise a first electric motor  50  affixed to the housing  71  and operably coupled to the imbalance mass shaft  72 . The example compacting machine  10  may also comprise a second electric motor  60  affixed to the housing  71  and operably coupled to the imbalance mass shaft  72 . The first electric motor  50  and the second electric motor  60  may be axially aligned along a shaft axis (e.g., axis of rotation  101 ) and affixed to the housing  71  on opposite sides of the housing  71 . 
     According to some example embodiments, the shaft axis (e.g., axis of rotation  101 ) may be perpendicular to a longitudinal axis  102  of the compacting plate  20 . The longitudinal axis  102  of the compacting plate  20  may bisect the compacting plate  20 . Additionally or alternatively, the imbalance mass shaft  72  may extend perpendicularly to the longitudinal axis  102  of the compaction plate  20 . Additionally or alternatively, the first electric motor  50  may comprise a first electric motor shaft  51  and the second electric motor  60  may comprise a second electric motor shaft  61 . The first electric motor shaft  51  and the second electric motor shaft  61  may extend along the shaft axis (e.g., the axis of rotation  101 ) transverse to the longitudinal axis  102  of the compaction plate  20 . Additionally or alternatively, the first electric motor  50  and the second electric motor  60  are controlled by control circuitry  32  to have a common rotational speed. Additionally or alternatively, the first electric motor  50  and the second electric motor  60  may be brushless motors, brushless direct current (BLDC) motors, brushed direct current (DC) motors, brushed alternating current (AC) motors, switched reluctance (SR) motors, or asynchronous motors. Additionally or alternatively, the first electric motor  50  may comprise a first electric motor shaft  51  and the second electric motor  60  may comprise a second electric motor shaft  61 . In this regard, the first electric motor shaft  51  may be rotationally fixed to the imbalance mass shaft  72  and the second electric motor shaft  61  is also rotationally fixed to the imbalance mass shaft  72  such that the first electric motor shaft  51 , the second electric motor shaft  61 , and the imbalance mass shaft  72  rotate together. Additionally or alternatively, the first electric motor  50  and the second electric motor  60  may be the only electric motors of the compaction machine  20  and the imbalance mass  78  may be the only imbalance mass of the compaction machine  10 . Additionally or alternatively, the imbalance mass  78  may be bisected by the longitudinal axis  102  of the compaction plate  20 . Additionally or alternatively, the housing  71  may be integrated with the compaction plate  20  such that the housing  71  and the compaction plate  20  are a unitary component. Additionally or alternatively, a torque output of the first electric motor  50  may be insufficient to rotate the imbalance mass  78  without contribution from the second electric motor  60 . Additionally or alternatively, the example compaction machine  10  may further comprise a power storage device  34 , wherein the first electric motor  50  and the second electric motor  60  are at least partially powered by the power storage device  34 . 
     According to some example embodiments, another example compaction machine  10  is provided. The example compacting machine  10  may comprise a compaction plate  20  and an imbalance mass assembly  70  operably coupled to the compaction plate  20 . The imbalance mass assembly  70  may comprise an imbalance mass shaft  72  and an imbalance mass  78  affixed to the imbalance mass shaft  72 . The example compacting machine  10  may also comprise a first electric motor  50  comprising a first electric motor shaft  51  that is operably coupled to the imbalance mass shaft  72  at a first end of the imbalance mass shaft  72 . The example compacting machine  10  may also comprise a second electric motor  60  comprising a second electric motor shaft  61  that is operably coupled to the imbalance mass shaft  72  at a second end of the imbalance mass shaft  72 . In this regard, the first end of the imbalance mass shaft  72  may be disposed opposite the second end of the imbalance mass shaft  72 . 
     According to some example embodiments, the compaction plate  20  may define a soil compacting surface (e.g., bottom surface  22 ), and the soil compacting surface may be defined by a plane  23  of the compaction plate  20 . The first electric motor shaft  51  and the second electric motor shaft  61  may rotate about a shaft axis (e.g., axis of rotation  101 ). In this regard, the shaft axis (e.g., axis of rotation  101 ) may be disposed parallel to the plane  23  of the compaction plate  20 . Additionally or alternatively, the first electric motor shaft  51  and the second electric motor shaft  61  may rotate about a shaft axis (e.g., axis of rotation  101 ), and the shaft axis (e.g., axis of rotation  101 ) may be perpendicular to a longitudinal axis  102  of the compacting plate  20 . Additionally or alternatively, the first electric motor  50  and the second electric motor  60  may be controlled by control circuitry  32  to have a common rotational speed. Additionally or alternatively, the first electric motor shaft  51  may be rotationally fixed to the imbalance mass shaft  72  and the second electric motor shaft  61  is also rotationally fixed to the imbalance mass shaft  72  such that the first electric motor shaft  51 , the second electric motor shaft  61 , and the imbalance mass shaft  72  rotate together. Additionally or alternatively, the imbalance mass  78  may be bisected by a longitudinal axis  102  of the compaction plate  20 . Additionally or alternatively, the unbalanced mass assembly  70  may comprise a housing  71  that is integrated with the compaction plate  20  such that the housing  71  and the compaction plate  20  are a unitary component. Additionally or alternatively, the example compacting machine  10  may further comprise a power storage device  34 . In this regard, the first electric motor  50  and the second electric motor  60  may be at least partially powered by the power storage device  34 . 
     Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements or functions, it should be appreciated that different combinations of elements or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits or solutions to problems are described herein, it should be appreciated that such advantages, benefits or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be thought of as being critical, required or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.