Transmission system for machine

A transmission system for a machine is coupled to an engine of the machine that is adapted to generate power. The transmission system includes a hydraulic power path including a variator coupled to the engine. The transmission system also includes a mechanical power path. The mechanical power path includes a first gear arrangement including a plurality of gears. The mechanical power path also includes a second gear arrangement including a plurality of gears. The second gear arrangement is coupled with the first gear arrangement to receive the variable rotational power from the first gear arrangement. The mechanical power path further includes a first clutch assembly and a second clutch assembly. Further, the second gear arrangement directs the variable rotational power received from the first gear arrangement towards a final output member of the machine in a selected direction.

TECHNICAL FIELD

The present disclosure relates to a transmission system associated with a machine.

BACKGROUND

A machine, such as a track type machine, may include a pair of tracks that allow movement of the machine on a ground surface. Typically, a transmission system is used to propel the machine based on power received from an engine of the machine. The transmission system may enable shifting of the machine between different speeds and directions.

Some track type machines, such as a track type tractor, include a hydromechanical transmission system. The hydromechanical transmission system includes a parallel power path having a hydraulic power path and a mechanical power path to realize the transmission function in the machine. Further, the mechanical power path of such transmission systems includes gear assemblies and clutches that allow selection of different speed ranges based on engagement and disengagement of the clutches. However, such transmission systems are generally bulky and have a complicated design and operation. Further, as such transmission systems include multiple components, an overall manufacturing and operating cost associated with the machine tends to increase. Moreover, such transmission systems generally require dedicated components and subassemblies for different machine platforms.

U.S. Pat. No. 3,897,697 describes a power transmission having an input section with planetary gearing providing a split power path from the input to a pair of idler gears wherein differing drive ratios exist in each branch of the split path. A hydraulic section having coupled variable displacement pump motor units links the two idler gears. By adjusting the displacements, the two idler gears may be constrained to rotate at any selected relative speed within a range of relative speeds and this enables progressive variation of the division of input power between the two branches of the split power path. An output section including additional planetary gearing provides for transmitting of power from either or both of the idler gears to an output means. Drive establishing devices in the input section provide for reversal of drive direction in each branch of the split power path and additional drive establishing devices in the output section provide for a plurality of speed ranges in both forward and reverse in each of which the infinite variation of drive ratio may be repeated. Drive establishing clutches and brakes need engage only under stationary conditions. These characteristics enable a single transmission configuration to be used in a variety of vehicles, of different power ratings, wherein a number of distinctly different transmissions have heretofore been necessary.

SUMMARY OF THE DISCLOSURE

In an aspect of the present disclosure, a transmission system for a machine is provided. The transmission system is coupled to an engine of the machine that is adapted to generate power. The transmission system includes a hydraulic power path including a variator coupled to the engine. The variator receives a portion of the power generated by the engine. The transmission system also includes a mechanical power path. The mechanical power path includes a first gear arrangement including a plurality of gears. The first gear arrangement is coupled with the variator and the engine and is operative to receive power from the variator and the engine. The mechanical power path also includes a second gear arrangement including a plurality of gears. The second gear arrangement is coupled with the first gear arrangement to receive the variable rotational power from the first gear arrangement. The mechanical power path further includes a first clutch assembly being selectively engageable to couple the first gear arrangement and the second gear arrangement. The mechanical power path includes a second clutch assembly being selectively engageable with at least one gear of the second gear arrangement. Further, the second gear arrangement directs the variable rotational power received from the first gear arrangement towards a final output member of the machine in a selected direction.

In another aspect of the present disclosure, a modular transmission kit for a machine is provided. The modular transmission kit is configured to be coupled to an engine of the machine that is adapted to generate power. The modular transmission kit includes a variator coupled to the engine. The variator receives a portion of the power generated by the engine. The modular transmission kit also includes a first gear arrangement including a plurality of gears. The first gear arrangement is coupled with the variator and the engine and operative to receive power from the variator and the engine. The modular transmission kit further includes a second gear arrangement including a plurality of gears. The second gear arrangement is coupled with the first gear arrangement to receive a variable rotational power from the first gear arrangement. Further, the second gear arrangement is configured to direct the variable rotational power in a selected direction. The modular transmission kit further includes a first clutch assembly being selectively engageable to couple the first gear arrangement and the second gear arrangement. The modular transmission kit includes a second clutch assembly being selectively engageable with at least one gear of the second gear arrangement. The modular transmission kit also includes an output module coupled with the second gear arrangement. The output module receives, from the second gear arrangement, the variable rotational power directed in the selected direction. Further, the output module is configured to adapt the variable rotational power directed in the selected direction to a final output member of the machine.

In yet another aspect of the present disclosure, a machine is provided. The machine includes an engine adapted to generate power. The machine also includes a transmission system coupled with the engine. The transmission system includes a hydraulic power path including a variator coupled to the engine. The variator receives a portion of the power generated by the engine. The transmission system also includes a mechanical power path. The mechanical power path includes a first gear arrangement including a plurality of gears. The first gear arrangement is coupled with the variator and the engine and operative to receive power from the variator and the engine. The mechanical power path also includes a second gear arrangement including a plurality of gears. The second gear arrangement is coupled with the first gear arrangement to receive the variable rotational power from the first gear arrangement. Further, the second gear arrangement is configured to direct the variable rotational power in a selected direction. The mechanical power path further includes a first clutch assembly being selectively engagable to couple the first gear arrangement and the second gear arrangement. The mechanical power path includes a second clutch assembly being selectively engagable with at least one gear of the second gear arrangement. The machine further includes a final output member coupled with the transmission system. The final output member receives, from the second gear arrangement, the variable rotational power directed in the selected direction.

DETAILED DESCRIPTION

Reference numerals appearing in more than one figure indicate the same or corresponding parts in each of them. References to elements in the singular may also 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 in the appended claims.

FIG. 1is a side view of a machine100, according to an embodiment of the present disclosure. In the illustrated embodiment, the machine100is embodied as a track type tractor. In alternative embodiments, the machine100may include an excavator, a dozer, a harvester, or any other type of machine known in the art having tracks for movement on a ground surface. The machine100may perform one or more machine operations associated with an industry such as mining, construction, farming, transportation, or any other industry known in the art. The machine100may be embodied as a manual, autonomous, or semi-autonomous machine, without any limitations.

The machine100includes a main frame102that supports various machine components thereon. An operator cab104is mounted on the main frame102. When the machine100is embodied as a manual or semi-autonomous machine, an operator of the machine100is seated within the operator cab104to perform one or more machine operations. The machine100also includes a work implement106coupled at a front end of the machine100. The work implement106is embodied as a blade. Further, the machine100additionally includes another work implement107, embodied as a ripper, coupled at a rear end of the machine100.

The machine100also includes an engine108(shown inFIG. 3) that generates power. The engine108may be an internal combustion engine such as a compression ignition diesel engine, but in other embodiments, the engine108might include a gas turbine engine. The engine108is mounted on the main frame102for providing propulsion power to the machine100. More particularly, the engine108is mounted within an enclosure110formed in the main frame102. Further, the main frame102rotatably supports an undercarriage system112. The undercarriage system112includes a pair of ground engaging members114each of which is embodied as a track in the illustrated embodiment ofFIG. 1. The ground engaging members114rotate in order to propel the machine100on ground surfaces.

Referring now toFIG. 2, the machine100includes a transmission system116. The transmission system116is embodied as a hydromechanical transmission system. The transmission system116is coupled with the engine108(seeFIG. 3) that generates power. More particularly, the transmission system116is disposed between the engine108and the ground engaging members114(seeFIG. 1) for adapting the power of the engine108to the ground engaging members114. The transmission system116described herein is embodied as a modular transmission kit116that includes a variator200, a first gear arrangement202, a second gear arrangement204, a first clutch assembly206, a second clutch assembly208, and an output module210. The transmission system116may be hereinafter interchangeably referred to as the modular transmission kit116.

Referring toFIG. 3, the transmission system116is connected to the engine108via an input member211. The input member211provides split power to a hydraulic power path212and a mechanical power path214through a first fixed input gear216and a second fixed input gear218, respectively. Further, the transmission system116includes the hydraulic power path212. The hydraulic power path212includes the variator200coupled to the engine108. The variator200receives a portion of the power generated by the engine108. In some examples, the variator200may receive approximately half of the power generated by the engine108.

The variator200includes a variable displacement pump220and a fixed displacement motor222. The pump220is fluidly interconnected with and arranged to operate the motor222. The pump220is drivingly connected to the engine108, through a hydrostatic transmission input gear224that engages with the first fixed input gear216. The motor222outputs through a hydrostatic transmission output gear225that engages with an input member227to the first gear arrangement202by way of a connection member229. Thus, the pump220of the transmission system116uses the split input power from the engine108to fluidly drive the motor222to convert the power received from the engine108to hydrostatic output power over a continuously variable speed ratio. The transmission of power through the engine108, the first fixed input gear216, the hydrostatic transmission input gear224, the variator200, and the hydrostatic transmission output gear225may be described as the hydraulic power path212.

Further, the transmission system116includes the mechanical power path214. The mechanical power path214includes the first gear arrangement202. The first gear arrangement202includes a plurality of gears226,230,233,228,232,235. The first gear arrangement202is coupled with the variator200and the engine108and is operative to receive power from the variator200and the engine108. Further, the first gear arrangement202is connected to the input member211to receive a portion of the power generated by the engine108. In some examples, the first gear arrangement202may receive approximately half of the power generated by the engine108. The input member211is connected to the first gear arrangement202via the second fixed input gear218and a connection member231. It should be noted that the connection members229,231may be embodied as gears.

The first gear arrangement202includes a first planetary gear arrangement221. The first planetary gear arrangement221includes a first sun gear226, a first planetary gear carrier230, and a first ring gear233. Further, the second planetary gear arrangement223includes a second sun gear228, a second planetary gear carrier232, and a second ring gear235. It should be noted that the first sun gear226is connected with the second ring gear235by a splined connection. Further, the first ring gear233is connected with the second sun gear228by a splined connection. The first gear arrangement202determines torque/speed reduction from an input that combines the hydraulic and mechanical power paths212,214. More particularly, the first gear arrangement202combines the hydrostatic output power from the hydraulic power path212and the split input mechanical power from the mechanical power path214to provide hydromechanical power to the second gear arrangement204. Thus, the first gear arrangement202provides a variable rotational power to the second gear arrangement204.

Further, the mechanical power path214includes the second gear arrangement204. The second gear arrangement204includes a plurality of gears234,236,238,239,240. The second gear arrangement204is coupled with the first gear arrangement202to receive the variable rotational power from the first gear arrangement202. The second gear arrangement204determines the direction of motion transmitted by the transmission system116, that is, whether the transmission system116is in forward or reverse. More specifically, the second gear arrangement204directs the variable rotational power received from the first gear arrangement202towards the final output member114of the machine100in a selected direction. In the illustrated embodiment, the final output member114is the ground engaging member114of the machine100. Accordingly, the final output member114may be hereinafter interchangeably referred to as the ground engaging member114.

The second gear arrangement204includes a planetary gear arrangement. More particularly, the second gear arrangement204includes a first sun gear234, a second sun gear236, a planet carrier237that supports a first set of planet gears238and a second set of planet gears239, and a ring gear240. The first sun gear234engages with the first set of planet gears238. Further, the second sun gear236engages with the second set of planet gears239. While the first and second gear arrangement202,204have been illustrated in a particular configuration herein, they may include any other configuration without any limitations.

The transmission system116also includes a first clutch assembly206. More particularly, the first clutch assembly206includes a first clutch242and a second clutch244. The first and second clutches242,244may include conventionally known clutches including rotatable discs that may be selectively coupled to other rotatably mounted discs to transmit power from one rotatable member to another. The first clutch assembly206is selectively engagable to couple the first gear arrangement202and the second gear arrangement204. In this way, the engagement of the gear228or the gear232of the first gear arrangement202with the first sun gear234of the second gear arrangement204determines the torque/speed reduction from the input that combines the hydraulic and mechanical power paths212,214.

The first gear arrangement202in conjunction with the selective engagement of the first clutch assembly206provides a speed reduction in a low gear range or a high gear range to the first sun gear234of the second gear arrangement204. In this embodiment, an engagement of the first clutch242provides the low gear range, while an engagement of the second clutch244provides the high gear range. More particularly, when the first clutch242is engaged, the second planetary gear carrier232of the first gear arrangement202is coupled with the first sun gear234of the second gear arrangement204thereby providing the low gear range. Further, when the second clutch244is engaged, the second sun gear228of the first gear arrangement202is coupled with the first sun gear234of the second gear arrangement204thereby providing the high gear range. In an example, the first clutch assembly206may be packaged in conjunction with the first gear arrangement202.

The transmission system116also includes a second clutch assembly208. More particularly, the second clutch assembly208includes a third clutch246and a fourth clutch248. The third and fourth clutches246,248may include conventionally known stationary clutches, also known as brakes, that affects a direction of power output from the second gear arrangement204. Further, the second clutch assembly208is selectively engagable with the gear236or the gear240of the second gear arrangement204. More particularly, the third or fourth clutches246,248may be selectively engaged with the gear236or the gear240, respectively, of the second gear arrangement204to determine the direction of power output from the second gear arrangement204to the output module210.

The selective engagement of the second clutch assembly208provides a forward gear range or a reverse gear range. In this embodiment, an engagement of the third clutch246provides the forward gear range, while an engagement of the fourth clutch248provides a reverse gear range. Further, the transmission system116also includes a fifth clutch250. In the illustrated embodiment, the engagement of the fifth clutch250provides the auxiliary gear range. The fifth clutch250may be selectively engaged to couple the input member211with the output member252. In an example, the second clutch assembly208may be packaged in conjunction with the second gear arrangement204, whereas the fifth clutch250may be disposed separate from the clutch assemblies206,208.

The engagement or disengagement of the clutch assemblies204,206and the fifth clutch250provides three forward gear ranges and two reverse gear ranges. As shown inFIG. 4, for a low-forward gear range operation, the first and third clutches242,246are engaged whereas the clutches244,248,250are disengaged. Further, for a low-reverse gear range operation, the first and fourth clutches242,248are engaged whereas the clutches244,246,250are disengaged. Additionally, for a high-forward gear range operation, the second and third clutches244,246are engaged whereas the clutches242,248,250are disengaged. Whereas, for a high-reverse gear range operation, the second and fourth clutches244,248are engaged whereas the clutches242,246,250are disengaged. Moreover, for the auxiliary gear range, the second and fifth clutches are engaged242,250whereas the clutches242,246,248are disengaged.

The transmission system116also includes the output module210. The output module210is disposed between the second gear arrangement204and the final output member114. The output module210is coupled with the second gear arrangement204. The output module210receives the variable rotational power directed in the selected direction from the second gear arrangement204. More particularly, the output module210adapts the variable rotational power that is directed in the selected direction to the final output member114of the machine100. It should be noted that the output module210is selected to adapt the output of the second gear arrangement204based on a configuration of the machine100. For example, dimensions of components of the output module210and an arrangement of the output module210may be varied based on a configuration of the machine100. The output module210is connected to the second gear arrangement204by an output member252.

In the illustrated embodiment, the output module210includes an output transfer gear arrangement254. The output transfer gear arrangement254may be designed to adapt an output provided by the output member252to a particular application. The output transfer gear arrangement254includes a first output gear256and a second output gear258. In the illustrated embodiment, the output member252provides rotation to the first output gear256that engages with the second output gear258. Further, the first and second output gears256,258intermesh a bevel gear260associated with a final drive arrangement262of the machine100. The bevel gear260in turn engages with the final output member114to rotate the final output member114at desired speeds and directions.

It should be noted that the output module210may be alternatively designed to facilitate adaptation of the output of the second gear arrangement204for specific applications. For example, fewer or additional structures may be provided, sizes, numbers, configuration and gear ratios of the gears may also be varied.

It is to be understood that individual features shown or described for one embodiment may be combined with individual features shown or described for another embodiment. The above described implementation does not in any way limit the scope of the present disclosure. Therefore, it is to be understood although some features are shown or described to illustrate the use of the present disclosure in the context of functional segments, such features may be omitted from the scope of the present disclosure without departing from the spirit of the present disclosure as defined in the appended claims.

INDUSTRIAL APPLICABILITY

An operation of the transmission system116will now be explained in relation toFIG. 3. Power generated by the engine108is delivered to the first gear arrangement202, via the hydraulic and mechanical power paths212,214. More specifically, rotation of the input member211provides power through the first fixed input gear216and the hydrostatic transmission input gear224to the variator200. The variator200provides power through the hydrostatic transmission output gear225to the input member227, via the connection member229. The connection member229is in turn coupled to the first sun gear226of the first gear arrangement202. Rotation of the input member211by the engine108likewise provides power through the second fixed input gear218and the connection member231to the first planetary gear carrier230of the first gear arrangement202.

Further, power from the first gear arrangement202is transmitted to the second gear arrangement204based upon selective engagement or disengagement of the first clutch assembly206. In the illustrated embodiment, the first and second clutch assemblies206,208may be selectively engaged or disengaged to provide a low-forward gear range, a high-forward gear range, a low-reverse gear range, and a high-reverse gear range. Further, the fifth clutch250may be selectively engaged or disengaged to provide the auxiliary gear range. More particularly, engagement of the first clutch242provides the low gear range, while engagement of the second clutch244provides the high gear range. The low and high gear ranges may be coupled with designation of the forward or reverse gear ranges based on engagement of the second clutch assembly208. Further, the auxiliary gear range may be provided by the engagement of second clutch244and the fifth clutch250. The selective engagement of the clutches242,244,246,248,250for each gear range is illustrated inFIG. 4.

Referring toFIG. 4, the first clutch242and the third clutch246are engaged to provide the low-forward gear range operation. Accordingly, the rotation of the second planetary gear carrier232of the first gear arrangement202is transmitted by way of the first clutch242to the first sun gear234of the second gear arrangement204. With the engagement of the third clutch246, the second sun gear236is held stationary. Power is further transmitted by the planet carrier237of the second gear arrangement204to the final output member114in the forward direction, via the output module210. However, when the first and fourth clutches242,248are engaged, the ring gear240is held stationary. As a result, the low gear range is provided to the final output member114in the reverse direction.

Further, the second and third clutches244,246are engaged to provide the high-forward gear operation. More particularly, when the second clutch244is engaged, the high gear range is obtained. Accordingly, the rotation of the second sun gear228of the first gear arrangement202is transmitted by way of the second clutch244to the first sun gear234of the second gear arrangement204. Further, with the engagement of the third clutch246, the second sun gear236is held stationary. Power is further transmitted by the planet carrier237of the second gear arrangement204to the final output member114in the forward direction, via the output module210. Further, when the fourth clutch248is engaged, the high gear range is provided in the reverse direction. More particularly, when the second and fourth clutches244,248are engaged, the ring gear240is held stationary. As a result, the high gear range is provided to the final output member114in the reverse direction.

The second gear arrangement204may additionally provide the auxiliary gear range to the final output member114. In the auxiliary gear range, the second clutch244and the fifth clutch250are engaged. As a result, power from the first gear arrangement202is transmitted by way of the second sun gear228of the first gear arrangement202to the first sun gear234of the second gear arrangement204. Further, this rotation is likewise transmitted by the planet carrier237of the second gear arrangement204to the final output member114in the forward direction, via the output module210.

As the first gear arrangement202provides motion to the transmission system116and the second gear arrangement204determines the range, the transmission system116may not require synchronizers, which are susceptible to damage during a synchronization process if a relative speed at the start of the synchronization process is high. Additionally, the variator200of the transmission system116includes the variable displacement pump220and the fixed displacement motor222which decreases complexity and is cost effective.

Further, as the first gear arrangement202provides motion to the transmission system116, the second gear arrangement204determines the range, and the output module210couples the transmission system116to the final output member114, standardized gear arrangements may be utilized for a number of applications by including the output module210tailored to the particular application. Thus, the transmission system116can be easily retrofitted in existing machines without making any major changes to the machine100. Further, the transmission system116includes a compact and robust L-shaped arrangement which allows easy accommodation of the transmission system116in a compact space, such as in machines having space limitations. Further, the transmission system116is packaged as a kit that allows easy replacement of the transmission system116during servicing or replacement schedules.

The transmission system116described herein is simple in design and operation and is cost effective. Further, the transmission system116improves fuel efficiency of the machine100. Moreover, the second gear arrangement204of the transmission system116includes fewer components thereby decreasing an overall cost and complexity of the transmission system116. Additionally, the transmission system116described herein is durable and provides improved reliability.