Patent Publication Number: US-2016238124-A1

Title: Transmission case for machine

Description:
TECHNICAL FIELD 
     The present disclosure relates to track-type machines and more particularly to a transmission case for a track-type machine. 
     BACKGROUND 
     In general, machines such as track-type tractors are employed for various construction or earthmoving tasks. Typically, a track-type tractor includes a transmission case and a main frame for supporting an engine and a transmission system drivably connected to the engine. The transmission case is defined by a set of plates including a rear plate. The rear plate acts as a seal, preventing lubricant leakage from the transmission case. Typically, the rear plate includes various components welded together. For example, a set of rear attachment mounting members are welded to the rear plate. Likewise, a transmission mounting ring is welded on the rear plate and then machined. Further, a plurality of machining operations such as drilling, boring, etc. are carried out on the rear plate after the rear plate is connected to the transmission case. Since the rear plate includes a number of components welded together, problems, such as leakage of lubricant from the transmission case often arise. Further, performing various manufacturing operations on the rear plate can be difficult and expensive, since these operations are required to be carried out after the installation of the rear plate on the rest of the transmission case. 
     SUMMARY OF THE DISCLOSURE 
     According to one aspect of the present disclosure, a transmission case for a machine is provided. The machine includes a power source and a drive train assembly adapted to receive power from the power source. The transmission case includes an encasing member. The transmission case also includes a pair of side rails. The side rails are coupled to the opposite ends of the encasing member. The pair of side rails extends along a longitudinal axis to form a frame assembly of the machine supporting the power source. The transmission case further includes a unitary rear wall. The unitary rear wall is coupled to the encasing member and the pair of side rails to define an enclosure. The enclosure is adapted to hold the drive train assembly. The unitary rear wall includes a rear plate. The rear plate includes plurality of threaded holes. The rear plate also includes a through hole. The plurality of threaded holes is provided at the peripheral end portions of the rear plate. The plurality of threaded holes enables connection of one or more rear attachments to the rear plate. The unitary rear wall also includes a machined portion. The machined portion is defined along the through hole. The machined portion supports the drive train assembly received within the enclosure. The unitary rear wall further includes a lubricant drain provision. The lubricant drain provision is provided at the bottom portion of the rear plate. The lubricant drain provision selectively allows drainage of lubricant contained in the enclosure. The unitary rear wall includes a plurality of mounts, which are provided on a top portion of the rear plate. The plurality of mounts facilitates in connection of a roll over protective structure to the rear plate. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a machine, according to an aspect of the present disclosure. 
         FIG. 2  is an exploded view of a frame assembly of machine of  FIG. 1  with various attachments connected to the frame assembly. 
         FIG. 3  is a perspective view of a frame assembly of the machine of  FIG. 1 . 
         FIG. 4  is a perspective view of a transmission case of  FIG. 2 ; and 
         FIG. 5  is a perspective view of a unitary rear plate of the transmission case of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. Moreover, references to various elements described herein are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. Any reference to elements in the singular is also to be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly. 
       FIG. 1  illustrates a side view of an exemplary machine  10 , according to one embodiment of the present disclosure. As illustrated, the machine  10  is embodied as a track type machine such as a track type tractor. Alternatively, the machine  10  may be a backhoe loader, a skid steer loader, a wheel loader, a motor grader, an excavator, a scraper, an agricultural tractor, a wheel loader, a haul truck, and the like. It should be understood that the machine  10  may embody any wheeled or tracked machine associated with mining, agriculture, forestry, construction, and other industrial applications. 
     Referring to  FIG. 1 , the machine  10  includes a frame assembly  12  and an engine enclosure  14 . The engine enclosure  14  houses a power source  16  (shown in  FIG. 3 ) to provide power to the machine  10 . The power source  16  may include one or more engines, power plants or other power delivery systems like batteries, hybrid engines, electric motors, or any other power sources known in the art. A set of ground engaging members  18  such as wheels, tracks, rollers and the like, are also provided on the machine  10  for propelling the machine  10 . Further, the machine  10  includes an operator cabin  20  which includes a plurality of input devices (not shown) for controlling and monitoring operations of the machine  10 . The input devices may include, but are not limited to, a push-button, a control lever, and a steering wheel. 
     The machine  10  includes a hydraulic pump (not shown). The hydraulic pump may be operatively coupled to the power source  16  to provide pressurized hydraulic fluid via a number of hoses  22  to a number of hydraulic cylinders  24  for lifting or otherwise moving the tools and implements. 
     The machine  10  includes a front attachment  26 . In the illustrated example, the front attachment  26  is embodied as a blade assembly. The machine  10  further includes a rear attachment  28 . The rear attachment  28  may include a ripper assembly, a winch assembly, a drawbar assembly or any other rear attachments known in the art. In the illustrated example, the rear attachment  28  is embodied as a ripper assembly. In an example, the rear attachment  28  may include, but is not limited to fixed parallelogram linkage configuration, variable parallelogram linkage configuration, fixed or variable shapes that are other than a parallelogram linkage configuration or any other ripper linkage configurations known in the art. 
     As shown in  FIG. 2 , the frame assembly  12  of the machine  10  includes a front portion  30  and a rear portion  32  opposite to the front portion  30  along a longitudinal axis X-X′. The power source  16  is mounted on the front portion  30  of the frame assembly  12  (shown in  FIG. 3 ). The rear portion  32  of the frame assembly  12  includes a transmission case  34 . The transmission case  34  of the frame assembly  12  supports the rear attachment  28 . 
     The rear attachment  28  includes a set of link members, such as a first link member  36 , a second link member  37 , a third link member  38  and a fourth link member  39 . Each of the set of link members includes a tractor mount. For example, the first link member  36  includes a first tractor mount  40 , the second link member  37  includes a second Exactor mount  41 , the third link member  38  includes a third tractor mount  42  and the fourth link member  39  includes a fourth tractor mount  43 . The first, the second, the third and the fourth tractor mounts  40 ,  41 ,  42 ,  43  of the rear attachment  28  are coupled to the transmission case  34  via a number of fastening members such as first fastening members  44 . Although, the figure illustrates four link members  36 ,  37 ,  38 ,  39  coupled to the transmission case  34 , the number of link members may vary based on system requirements. 
     The transmission case  34  also supports a Roll Over Protective Structure  46  (hereinafter referred to as “ROPS  46 ”) of the operator cabin  20 . The ROPS  46  includes a first connecting structure  48  and a second connecting structure  50 . The first connecting structure  48  includes a first bar member  52 . The first connecting structure  48  further includes a first flange  54 . The first flange  54  is secured to the bottom end of the first bar member  52 . The second connecting structure  50  includes a second bar member  56 . The second connecting structure  50  further includes a second flange  58 . The first flange  54  and the second flange  58  of the ROPS  46  are coupled to the transmission case  34  of the frame assembly  12  via a number of second fastening members  60 . The first and the second fastening members  44 ,  60  may include, but are not limited to screws, bolts, rivets or any other fastening elements known in the art. 
     Referring to  FIGS. 3 and 4 , the transmission case  34  of the frame assembly  12  includes an encasing member  62 . The encasing member  62  includes an opening  64  for receiving an output shaft  66  from the power source  16 . In alternative examples, where the power source  16  is an electric motor instead of a traditional transmission, the encasing member  62  will not have the opening  64  for receiving the output shaft  66 . The encasing member  62  may be manufactured from a variety of materials including, but not limited to carbon steel, alloy steel, aluminum alloys or any other materials known in the art. 
     The transmission case  34  includes a first mount  68  and a second mount  69 . The first mount  68  and the second mount  69  are secured to the encasing member  62  by welding. The transmission case  34  includes a pair of side rails  70 . The side rails  70  are coupled to the opposite ends of the encasing member  62  by welding, fastening, riveting, or by other fixed or removable connecting means known in the art. The side rails  70  extend along the longitudinal axis X-X′ to form the frame assembly  12  of the machine  10 . The side rails  70  may be manufactured from materials including, but not limited to steel plate, cast materials, composite materials or any other materials known in the art. 
     The transmission case  34  further includes a unitary rear wall  72 . The unitary rear wall  72  is coupled to the encasing member  62  and the side rails  70  to define an enclosure  74 . The enclosure  74  houses a drive train assembly (not shown) of the machine  10 . Further, the enclosure  74  also houses the transmission lubricant provided for the operation of the drive train assembly. The drive train assembly receives power from the power source  16 . The drive train assembly may include a mechanical drive, a hydraulic drive, or a combination thereof. The transmission case  34  includes an annular shaped plate  76  (as shown in  FIG. 2 ). 
     Referring to  FIG. 5 , the unitary rear wall  72  includes a rear plate  78  with a thickness ‘T 1 ’ and a width ‘W’. The rear plate  78  may be made from variety of materials including, but not limited to alloy steel, cast iron or any other materials known in the art. The rear plate  78  may be manufactured using variety of manufacturing process including, but not limited to casting, molding, or any other manufacturing processes known in the art. 
     The rear plate  78  includes a number of threaded holes  80  and a through hole  82 , Although the rear plate  78  disclosed herein includes the threaded holes  80 , it may be contemplated that the rear plate  78  may include different types of holes known in the art. The rear plate  78  includes a first peripheral end portion  84 , a second peripheral end portion  85 , a third peripheral end portion  86  and a fourth peripheral end portion  87 . The threaded holes  80  are provided at the first, the second, the third and the fourth peripheral end portions  84 ,  85 ,  86 ,  87  of the rear plate  78 . The threaded holes  80  receive the first fastening members  44  thereby, respectively securing the first, the second, the third and the fourth tractor mounts  40 ,  41 ,  42 ,  43  of the rear attachment  28  to the rear plate  78  of the transmission case  34  (shown in  FIG. 2 ). Further, the rear plate  78  may also include additional threaded holes (not shown) around the through hole  82 . The additional threaded holes may be used to mount the transmission or the electric motor. 
     The unitary rear wall  72  further includes a machined portion  88 . The machined portion  88  is defined along the through hole  82 . In an illustrated example, the machined portion  88  may have a circular profile. Alternatively, the machined portion  88  may have elliptical profile, oval profile or any other similar profile known in the art. The machined portion  88  includes a number of threaded holes  89 . The threaded holes  89  receive a number of third fastening members  90 . The third fastening members  90  couples the annular shaped plate  76  to the machined portion  88 (shown in  FIG. 2 ). The annular shaped plate  76  is configured to support the drive train assembly within the enclosure  74 . The third fastening members  90  may include, but are not limited to screws, bolts or any other fastening elements known in the art. 
     Referring to  FIG. 5 , the unitary rear wall  72  includes a top portion  92  and a bottom portion  94  opposite to the top portion  92 . The unitary rear wall  72  includes a lubricant drain opening  95 . The lubricant drain opening  95  is located at the bottom portion  94  of the rear plate  78 . The lubricant drain opening  95  is configured to selectively allow drainage of lubricant from the enclosure  74  ( FIG. 4 ). The unitary rear wall  72  includes a third mount  96  and a fourth mount  98 . The third and the fourth mounts  96 ,  98  are located on the top portion  92  of the unitary rear wall  72 . The first, the second, the third and the fourth mounts  68 ,  69 ,  96 ,  98  receive the second fastening members  60 , securing the first connecting structure  48  and the second connecting structure  50  of the roll over protective structure  46 . The thickness ‘T 1 ’ of the rear plate  78  may be selected such that the rear plate  78  withstands the combined forces exerted on the frame assembly  12  by different components mounted on the frame assembly  12 . The width ‘W’ of the rear plate  78  may be selected such that it defines a width of the rear portion  32  of the frame assembly  12 . 
     INDUSTRIAL APPLICABILITY 
     The present disclosure relates to the unitary rear wall  72  for the transmission case  34  of the machine  10 . The unitary rear wall  72  reduces number of components being used thereby easing the machine  10  assembly and/or avoid or limit the introduction of structural weakness into the frame assembly  12  of the machine  10 . The unitary rear wall  72  improves the overall durability and simplifies the overall structure of the transmission case  34 . The third and fourth mounts  96 ,  98  present on top of the rear plate  78  facilitates mounting of the ROPS  46 . The threaded holes  80  present on the first, the second, the third and the fourth peripheral end portion  84 ,  85 ,  86 ,  87  of the rear plate  78  receives the first fastening members  44  through the first, the second, the third and the fourth tractor mounts  40 ,  41 .,  42 ,  43  facilitating in the mounting of the rear attachment  28 . 
     The width ‘W’ of the rear plate  78  of the unitary rear wall  72  leads to improved manufacturability of the frame assembly  12 . Since the threaded holes  80  are readily provided on the rear plate  78  machining of the rear plate  78  whilst the rear wall is attached to the transmission case  34  may be avoided. It is contemplated that the unitary rear wall  72  efficiently prevents lubricant oil leakage from the transmission case  34 . The lubricant drain opening  95  provided at the bottom portion  94  of the rear plate  78  of the unitary rear wall  72 , facilitates smooth draining of the lubricant present in the enclosure  74  of the transmission case  34 . 
     While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.