CN104321562B - For performing the system and method for shuttle-type speed change by the actuating device of working truck - Google Patents

Abstract

The present invention discloses a method for performing a shuttle shift by means of a transmission of a work vehicle, wherein the transmission comprises an input shaft, a counter shaft and a plurality of driven shafts which are connected to the input shaft and the counter shaft The axes extend approximately parallel. The method may include disengaging a clutch associated with a first directional gear of a directional shaft of the plurality of driven shafts. The first directional gear may be configured to rotate the directional shaft in a first direction. Additionally, the method may include engaging clutches associated with at least two gears of at least one secondary driven shaft of the plurality of driven shafts to reduce the speed of the steering shaft, and after the speed of the steering shaft is reduced, causing the A clutch associated with the second directional gear of the directional shaft is engaged to rotate the directional shaft in the second direction.

Description

System and method for performing a shuttle shift with a transmission of a work vehicle

Cross References to Related Applications

This application is based upon and claims priority to U.S. Provisional Patent Application No. 61/656,559, filed June 7, 2012, entitled "System and Method for Performing Shuttle Shifts with a Transmission of a Work Vehicle," the entire disclosure of which is reproduced by This is hereby incorporated by reference for all purposes.

technical field

The present subject matter generally relates to work vehicles, and more particularly, the present subject matter relates to systems and methods for performing shuttle shifts with a transmission of a work vehicle.

Background technique

Work vehicles, such as farm vehicles, bulldozers, off-road vehicles, loaders, and/or the like, often include a power shift transmission equipped with the ability to perform shuttle shifts, wherein the work vehicle's The direction of travel can be reversed without requiring the operator to change gears or use a clutch. For example, to change the direction of travel from forward to backward, the operator would simply need to move a shuttle lever disposed within the operator compartment from a forward position to a rearward position.

In order to increase the productivity and efficiency of work vehicles, efforts have been made to reduce the amount of time required to perform a shuttle change on a transmission. However, in order to reduce the time required to perform a shuttle shift, the magnitude of the load transmitted through the transmission must be increased in magnitude. For example, in order to perform a shuttle shift quickly, the inertia of the high speed components of the transmission and the momentum of the work vehicle must be overcome in a short period of time by the clutches of the transmission. This results in the transmission of substantial thermal and torque loads through the clutches that would otherwise significantly damage the clutches and/or other components of the transmission.

Currently, conventional shuttle shifting methods utilize a clutch associated with the transmission's directional gear to slow down and reverse the direction of the transmission's shaft. For example, if the work vehicle is initially traveling in a forward direction, the clutch associated with the forward gear may be disengaged when a shuttle shift is initiated. The clutch associated with the reverse gear may then be engaged to slow or stop one or more of the transmission shafts and to accelerate such one or more shafts in the opposite direction. However, the one or more shafts associated with the forward and reverse gears are typically one or more high speed shafts configured to be driven directly by the input shaft (or indirectly via counter shafts). Thus, the clutches for the forward and reverse gears are typically configured to transmit lower torque loads than the clutches associated with the other low speed shafts of the transmission. Specifically, the clutches for the forward and reverse gears are often small and have low torque carrying capacity. As a result, the use of such clutches in performing shuttle shifts can result in significant damage to the clutches and/or other components of the transmission.

Accordingly, what would be appreciated in the art would be a system and method for performing a shuttle shift that lowers one or more of the components of the transmission of a work vehicle. Multiple possibilities for damage to occur.

Contents of the invention

Aspects and advantages of the invention will be set forth in part in the description which follows, or may be obvious from the description which follows, or may be learned by practice of the invention.

In one aspect, the subject matter of the invention relates to a method for performing a shuttle shift by means of a transmission of a work vehicle, wherein the transmission comprises an input shaft, a counter shaft and a plurality of driven shafts, the driven shafts Extends approximately parallel to the input shaft and the counter shaft. The method may generally include disengaging a clutch associated with a first directional gear of a directional shaft of the plurality of driven shafts. The first directional gear may be configured to rotate the directional shaft in a first direction. Additionally, the method may include engaging clutches associated with at least two gears of at least one secondary driven shaft of the plurality of driven shafts to reduce the speed of the steering shaft, and after the speed of the steering shaft is reduced, causing the A clutch associated with the second directional gear of the directional shaft is engaged to rotate the directional shaft in the second direction.

In another aspect, the inventive subject matter relates to a system for performing a shuttle shift while operating a work vehicle. The system may generally include a transmission having an input shaft, a counter shaft, and a plurality of driven shafts extending generally parallel to the input shaft and the counter shaft. The driven shaft may include a steering shaft and at least one secondary shaft. Additionally, the system can include a controller communicatively coupled to the transmission. The controller may be configured to disengage a clutch associated with the first directional gear of the directional shaft when the directional shaft is rotated in the first direction. The controller may also be configured to engage clutches associated with at least two gears of the at least one secondary driven shaft to reduce the rotational speed of the directional shaft after disengagement of the clutch associated with the first directional gear. Additionally, the controller may be configured to engage a clutch associated with a second directional gear of the directional shaft to rotate the directional shaft in the second direction after the rotational speed of the directional shaft decreases.

These and other features, aspects and advantages of the present invention will be better understood with reference to the following specification and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

Description of drawings

For those skilled in the art, the full disclosure of the present invention (including the best mode of the present invention) will be clarified in the description. This description refers to the accompanying drawings, in which:

Figure 1 shows a side view of one embodiment of a work vehicle;

Figure 2 shows a simplified schematic diagram of one embodiment of a transmission suitable for use in the work vehicle shown in Figure 1;

3 shows a schematic diagram of one embodiment of a system for performing shuttle shifts with a transmission of a work vehicle; and

FIG. 4 shows a flow chart of an exemplary embodiment of a method for performing a shuttle shift using a transmission of a work vehicle.

detailed description

Embodiments of the invention will now be described in detail, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and changes can be made in the present invention without departing from the scope and spirit of the invention. For example, features illustrated or described as part of one embodiment can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and changes as come within the scope of the appended claims and their equivalents.

Referring now to the drawings, FIG. 1 shows a side view of one embodiment of a work vehicle 10 . As shown, work vehicle 10 is configured as an agricultural tractor. However, in other embodiments, work vehicle 10 may be configured as any other suitable work vehicle known in the art, for example, various other agricultural vehicles, bulldozers, loaders, and/or various other off-road vehicles. car.

As shown in FIG. 1 , work vehicle 10 includes a pair of front wheels 12 , a pair of rear wheels 14 and a chassis 16 coupled to and supported by wheels 12 , 14 . Operator compartment 18 may be supported by portions of chassis 16 and may house various control devices 20 (eg, levers, pedals, control panels, and/or the like) for allowing an operator to control operation of work vehicle 10 . For example, one of the control devices 20 may include a shuttle lever (or shuttle button) configured to allow the operator to switch between a forward mode, a neutral mode, and a reverse mode of operation (including operator-initiated shuttle ability to shift speed). Additionally, work vehicle 10 may include a transmission 24 and an engine 22 mounted on chassis 16 . Transmission 24 may be operatively coupled to engine 22 (eg, via a damping coupling) and may provide a variably adjustable gear ratio for transferring engine power to wheels 14 via axle/differential 26 . Engine 22 , transmission 24 and axle/differential 26 may collectively define a driveline 28 of work vehicle 10 .

It should be appreciated that the transmission 24 may generally comprise any suitable transmission known in the art having a plurality of different fixed gear ratios. For example, in several embodiments, transmission 24 may include a multi-speed power-variable transmission having multiple selectable gear ratios (e.g., multiple selectable forward gear ratios and reverse gear ratios) ); and a plurality of hydraulically actuated clutches that can be selectively actuated to engage the transmission in different gear ratios. In such embodiments, the clutch may be configured to be automatically engaged within the transmission 24 . For example, electronic controller 102 of work vehicle 10 (described below with reference to FIG. 3 ) may be configured to send appropriate control commands or signals to transmission 24 directing transmission 24 to actuate a hydraulic piston or to actuate other suitable, configured An actuator that engages/disengages the clutch. In other embodiments, transmission 24 may include any other transmission suitable for use with work vehicle 10 , such as a continuously variable transmission.

It should also be understood that the configuration of the above-described work vehicle 10 shown in FIG. 1 is provided merely to place the subject matter of the present invention in an exemplary field of use. Thus, it should be appreciated that the inventive subject matter may be readily adapted to any form of work vehicle configuration 10 . For example, in an alternative embodiment, a separate frame or chassis coupled with the engine 22, transmission 24, and differential 26 could be provided in a common configuration in a smaller tractor. Still other configurations may use an articulated chassis to steer work vehicle 10 or rely on tracks instead of wheels 12 , 14 . Additionally, although not shown, work vehicle 10 may also be configured to be operatively coupled to any suitable type of work implement, such as a trailer, boom, manure tank, forage grinder, plow, and/or the like.

Referring now to FIG. 2 , a simplified schematic diagram of one embodiment of a transmission 24 suitable for use with the work vehicle 10 described above is shown in accordance with aspects of the present inventive subject matter. As shown, the transmission 24 includes a plurality of shafts that extend parallel to each other. For example, the transmission 24 may include an input shaft 30 operably connected to and driven by the engine 22 . The transmission 24 may also include a countershaft 32 extending parallel to the input shaft 30 for facilitating a rearward gear ratio of the transmission 24 . Additionally, the transmission 24 may include a plurality of driven shafts 34, 36, 38 extending parallel to the input and counter shafts 30, 32, the driven shafts 34, 36, 38 forms different levels of direct gear engagement for adjusting the gear ratio of transmission 24 .

For example, as shown, in the depicted embodiment, transmission 24 includes: a directional shaft 34 forming a first stage direct gear engagement; an intermediate shaft 36 forming a second stage a direct gear engagement; and an output shaft 38 forming a third stage direct gear engagement. Steering shaft 34 may generally be configured to be driven through input shaft 30, either directly or indirectly via countershaft 32, to control the direction of rotation of driven shafts 34, 36, 38, and thus, the direction of travel of the work vehicle (i.e., toward forward or backward). For example, by engaging one of the forward directional gears 46, 48 (described below) of the directional shaft 34 such that the input shaft 30 directly drives the directional shaft 34, the transmission 24 may be engaged in a forward gear ratio, thereby causing Work vehicle 10 moves forward. Similarly, transmission 24 may be engaged in a rearward gear ratio by engaging rearward direction gear 54 (described below) of steering shaft 34 such that input shaft 30 indirectly drives steering shaft 34 via countershaft 32 , thereby Work vehicle 10 is urged to move backward. Additionally, as shown in FIG. 2 , the intermediate shaft 36 may be configured to be driven by the directional shaft 34 and the output shaft 38 may be configured to be driven by the intermediate shaft 36 . As is generally understood, the output shaft 38 may be coupled to the differential 26 to allow rotational motion of the output shaft 38 to be transferred to the wheels 14 of the work vehicle 10 .

It should be understood that in alternative embodiments, transmission 24 may include any other number of driven shafts to form a corresponding number of stages of direct gear engagement. For example, in various embodiments, transmission 24 may include only two driven shafts to form a two-stage direct gear engagement (eg, by simply including direction shaft 34 and output shaft 38 ), or transmission 24 may include four One or more driven shafts to form four or more stages of direct gear engagement (eg, by including a direction shaft 34, two or more intermediate shafts 36, and an output shaft 38).

Additionally, the transmission 24 may also include a plurality of gears mounted on parallel shafts 30 , 32 , 34 , 36 , 38 . For example, as shown, in the illustrated embodiment, the transmission 24 includes eight pairs of gears configured to provide eight forward gear ratios and four reverse gear ratios. Specifically, as shown in FIG. 2 , the transmission 24 may include a first input gear 40 , a second input gear 42 , and a third input gear 44 mounted to the input shaft 30 . The first input gear 40 can drive a first forward gear 46 configured for selective engagement with the steering shaft 34 . Similarly, the second input gear 42 may drive a second forward gear 48 configured for selective engagement with the steering shaft 34 . The third input gear 44 may generally be configured to drive countershaft 32 . For example, as shown in FIG. 2 , the pair of shafts 32 may include a first pair of gears 50 and a second pair of gears 52 mounted on the pair of shafts 32 , the first pair of gears 50 being driven by the third input gear 44 . The second pair of gears 52 may in turn drive a rearward gear 54 configured for selective engagement with the steering shaft 34 .

Additionally, the transmission 24 may include a first drive gear 56 and a second drive gear 58 mounted to the directional shaft 34 and a third drive gear 60 and a fourth drive gear 62 mounted to the intermediate shaft 36 . The drive gears 56 , 58 , 60 , 62 may generally be adapted to drive corresponding driven gears 64 , 66 , 68 , 70 configured to mate with the intermediate shaft 36 and the output shaft 38 Selectively engaged. For example, as shown, in the illustrated embodiment, the first drive gear 56 may drive a first driven gear 64 configured to selectively engage with the countershaft 36 and the second The second drive gear 58 can drive a second driven gear 66 configured to selectively engage with the intermediate shaft 36 . Similarly, third drive gear 60 may drive third driven gear 68 configured for selective engagement with output shaft 38 , and fourth drive gear 62 may drive fourth driven gear 70 , the fourth driven gear 70 is configured to selectively engage with the output shaft 38 .

It should be understood that in alternative embodiments, transmission 24 may include any other number of gear pairs configured to provide any suitable number of forward and reverse gear ratios. For example, in some work vehicles, it may be desirable for transmission 24 to include a larger number of gear pairs, thereby providing a larger number of forward and/or reverse gear ratios (e.g., 24 or greater forward gear ratio) to accommodate complex load conditions.

Additionally, as shown in FIG. 2 , the transmission 24 may also include a plurality of hydraulically actuated clutches 72 for engaging the gear pairs with the driven shafts 34 , 36 , 38 . Specifically, each clutch 72 may be associated with one of such gears (eg, first forward gear 46, second forward gear 48, rearward gear 54, first driven gear 64, second driven gear 66, the third driven gear 68 and the fourth driven gear 70), that is, the gears are configured to selectively engage with one of the driven shafts 34, 36, 38. In several embodiments, each clutch 72 may include one or more hydraulic pistons or other suitable hydraulic actuators 74 configured to engage a corresponding friction plate 76 coupled to and from the gears. Both shafts. Thus, when pressurized hydraulic fluid is supplied within the clutch 72, the friction plates 76 may be pressurized together such that the plates 76 frictionally and rotationally engage each other, thereby allowing movement between the parallel shafts 30, 32, 34, Torque is transmitted between the two shafts in 36, 38. For example, torque may be transferred from the input shaft 30 to the steering shaft 34 via the gear pair including the first input gear 40 and the first forward gear 46 by actuating the clutch 72 associated with the first forward gear 46 . Similarly, torque may be transferred from the directional shaft 34 to the intermediate shaft 36 and from the intermediate shaft 36 to the output shaft 38 by actuating a clutch 72 associated with each of the driven shafts 36 , 38 . Thus, by varying the combination of clutches 72 that are actuated within the transmission 24 (i.e., one clutch 72 per driven shaft 34, 36, 38), the transmission 24 can be shifted in various forward gears. ratio and reverse gear ratio engagement.

Referring now to FIG. 3 , a schematic diagram of one embodiment of a system 100 for performing shuttle shifts with the transmission 24 of the work vehicle 10 is shown in accordance with aspects of the present subject matter. As shown, the system 100 may include a controller 102 configured to control operation of various components disposed within and/or associated with the transmission 24 . For example, as will be described in more detail below, the controller 102 may be communicatively coupled to one or more valves disposed within and/or associated with the transmission 24 (e.g., the system valve 104 and multiple clutch valve 106 ) to control the pressure of hydraulic fluid supplied within the transmission 24 , thereby allowing the controller 102 to control the engagement and/or disengagement of the various clutches 72 of the transmission 24 .

It should be appreciated that controller 102 may generally include any suitable computer and/or other processing unit, including any suitable combination of computers and/or other processing units. Thus, in several embodiments, controller 102 may include one or more processors and associated one or more memory devices configured to perform various computer-implemented functions. As used herein, the term "processor" refers not only to an integrated circuit included in a computer as in the technical field, but also to a controller, microcontroller, microcomputer, programmable logic control devices (PLC), application-specific integrated circuits, and other programmable circuits. Additionally, the one or more storage devices of controller 102 may typically include one or more storage elements including, but not limited to, computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile volatile media (eg, flash memory), floppy disk, compact disk read-only memory (CD-ROM), magneto-optical disk (MOD), digital versatile disk (DVD), and/or other suitable storage elements. Such one or more storage devices may generally be configured to store suitable computer-readable instructions that, when executed by one or more processors, configure controller 102 to, for example, perform the operations described below with reference to FIG. 4 . The steps and/or operations of the method 200 described above are used to perform various computer-implemented functions. Additionally, controller 102 may also include various other suitable components, such as communication circuitry or modules, one or more input/output channels, data/control buses, and/or the like.

Additionally, the system 100 may also include one or more sensors 108 configured to monitor the rotational speed of the various shafts 30 , 32 , 34 , 36 , 38 of the transmission 24 . For example, as shown in FIGS. 2 and 3 , transmission 24 may in one embodiment include mounting to each shaft 30 , 32 , 34 , 36 , 38 and/or mounting to each shaft 30 , 32 , One or more speed sensors 108 (eg, shaft encoders, shaft sensors, and/or any other suitable speed sensors) within 34, 36, 38 to measure shaft rotational speed. Speed sensors 108 may in turn be communicatively coupled to controllers 102 to allow speed measurements to be communicated to one or more controllers 102 for subsequent processing and/or analysis.

Additionally, system 100 may also include various components for supplying hydraulic fluid into and/or within transmission 24 . For example, as shown, in the illustrated embodiment, the system 100 may include a holding tank 110 configured to hold or otherwise contain hydraulic fluid to be supplied within the transmission 24 . Additionally, system 100 may include a pump 112 configured to divert hydraulic fluid from holding tank 110 to pressure control valve 104 (hereinafter “system valve 104 ”) positioned downstream of pump 112 . System valve 104 may be communicatively coupled to controller 102 such that operation of valve 104 may be electronically controlled to regulate the pressure of hydraulic fluid supplied to clutch 72 of transmission 24 . Thus, it should be understood that system valve 104 may generally comprise any suitable electronic valve that may be configured to provide a variable pressure output. For example, in one embodiment, system valve 104 may comprise an electronic solenoid activated proportional valve or any other suitable variable pressure control valve.

By controlling operation of the system valve 104 , the controller 102 may be configured to regulate a specific pressure at which hydraulic fluid is supplied to all clutches 72 (hereinafter “system pressure”). Additionally, the controller 102 may also be configured to individually adjust the pressure of hydraulic fluid supplied within each clutch 72 . Specifically, as shown in FIG. 3 , each clutch 72 may include an individual clutch valve 106 configured to regulate the pressure of hydraulic fluid supplied to its corresponding hydraulic actuator 74 (hereinafter called "clutch pressure"). Each clutch valve 106 may be communicatively coupled to controller 102 such that operation of valve 106 may be electronically controlled. Thus, when a particular clutch 72 is to be engaged within the transmission 24 , its clutch valve 106 may be controlled to supply hydraulic fluid to the corresponding actuator 74 at a given clutch pressure.

Similar to the system valve 104 described above, it should be understood that the clutch valve 106 may generally comprise any suitable electronic valve that may be configured to provide a variable pressure output. For example, in one embodiment, each clutch valve 106 may comprise an electronic solenoid activated proportional valve or any other suitable variable pressure control valve.

During operation of the disclosed system 100, the controller 102 may be configured to receive various system inputs. For example, in several embodiments, the controller 102 may be configured to receive a shuttle shift command (eg, from one or more of the control devices 20 housed within the cab 18 ) directing the controller to perform a shuttle shift. Upon receiving a shuttle shift command, controller 102 may be configured to send appropriate control commands to clutch valve 106 for disengaging and/or engaging clutch 72 of transmission 24 according to the method described below with reference to FIG. 4 .

Referring now to FIG. 4 , a flowchart of one embodiment of a method 200 for performing a shuttle shift with the transmission 24 of the work vehicle 10 is shown in accordance with aspects of the present inventive subject matter. As shown, the method 200 generally includes: step 202, disengaging the clutch associated with the first directional gear of the directional shaft of the transmission; step 204, disengaging at least two gears associated with the secondary driven shaft of the transmission The associated clutch is engaged to reduce the rotational speed of the directional shaft; and step 206 , engaging the clutch associated with the second directional gear of the directional shaft after the rotational speed of the directional shaft is decreased.

In general, the disclosed method 200 may allow clutches associated with the directional gears of the transmission 24 (ie, the first forward gear 46, the second forward gear 48, and the rear gear 54) to be overheated or overloaded without overheating or overloading. Perform a shuttle shift. Specifically, at the beginning of a shuttle shift, the directional gear that is engaged with (i.e., the directional gear is the first forward gear 46 or the second forward gear 48 if the vehicle 10 is traveling forward, or the first forward gear 48 if the vehicle is traveling backward, The clutch 72 associated with the directional gear (reverse gear 54) can then be disengaged, thereby disengaging the input shaft 30 from the directional shaft 34 and stopping the transfer of torque from the engine 22 to the transmission 24. Thereafter, instead of immediately engaging the clutch 72 associated with the opposite directional gear, the clutch 72 associated with at least two gears of a secondary driven shaft of the transmission 24 (e.g., intermediate shaft 36 or output shaft 38) may is engaged to stop or otherwise reduce the rotational speed of the steering shaft 34 (eg, via the "four-squaring" effect). Once the directional shaft 34 is stopped or its speed is otherwise significantly reduced, the clutch 72 associated with the opposing directional gear may then be engaged to allow the directional shaft 34 to rotate in the opposite direction.

It should be appreciated that the steering shaft 34 is stopped or otherwise reduced by using the clutch 72 associated with the intermediate shaft 36 and/or the output shaft 38 and then increased by using the clutch 72 associated with the appropriate steering gear. With the rotational speed of the general direction shaft 34 in opposite directions, the load transmitted through the transmission 24 during a shuttle shift can be shared or split between different sets of clutches 72 . As such, the average load carried by each clutch 72 may be reduced. Additionally, since the clutches 72 associated with the intermediate shaft 36 and the output shaft 38 are typically more robust and have a significantly higher torque carrying capacity than the clutches 72 associated with the directional shaft 34, such clutches 72 are better equipped to Distributing heat and/or withstanding loads associated with decelerating and/or stopping the directional shaft 34 during shuttle shifting. Thus, by using the clutch 72 associated with the countershaft 36 and the output shaft 38, the heat and torque loads associated with shuttle shifting can be directed away from the weaker clutch 72 of the directional shaft 34, thereby preventing component breakage and The life and reliability of the overall transmission 24 is enhanced.

It should also be understood that in several embodiments, the disclosed method 200 may be implemented automatically using the controller 102 of the work vehicle 10 . For example, as described above, the controller 102 may be configured to receive operator input (eg, in the form of a shuttle shift command) indicating that a shuttle shift is to be performed. Upon receiving operator input, the controller 102 may in turn control the pressure of hydraulic fluid supplied to the transmission to engage and/or disengage the appropriate clutch 72 .

As shown in FIG. 4, at step 202, at the beginning of the shuttle shift, the controller 102 may be configured to disengage the clutch 72 associated with the currently engaged directional gear, thereby disengaging the directional shaft 34 from the input shaft 30. open. In particular, the controller 102 may be configured to disengage the clutch 72 associated with the first forward gear 46 or the second forward gear 48 if the work vehicle 10 is traveling in a forward direction when the shuttle shift begins. For example, the controller 102 may be configured to send appropriate control signals to the one or more clutch valves 106 to control the supply of hydraulic fluid to the clutch 72 for either the first forward gear 46 or the second forward gear 48 to reduce the supply The pressure of the hydraulic fluid to this clutch 72 . Similarly, if the work vehicle 10 is traveling in the reverse direction when the shuttle shift begins, the controller 102 may be configured to associate the reverse gear 54 with, for example, by reducing the hydraulic fluid pressure supplied to such clutch 72 . The clutch 72 is disengaged.

Additionally, at step 204, after the clutches 72 associated with the appropriate directional gears are disengaged, the controller 102 may be configured to engage the clutches 72 associated with at least two gears of the individual driven shafts of the transmission 24, In order to stop the steering shaft 34 or otherwise reduce the rotational speed of the steering shaft 34 . For example, in several embodiments, clutch 72 for driven gears 64 , 66 of countershaft 36 may be engaged to stop or otherwise slow down directional shaft 34 . Specifically, as shown in FIG. 2 , the clutches 72 for the first driven gear 64 and the second driven gear 66 of the intermediate shaft 36 may be simultaneously engaged. In such an embodiment, it should be understood that one of the clutches 72 of the countershaft 36 may already be engaged at the start of the shuttle shift. Thus, once the appropriate directional gear is disengaged in step 202 of the disclosed method 200 , the clutch 72 of the countershaft 36 that was previously engaged may remain engaged while maintaining the clutch engagement. Such simultaneous engagement of the two clutches 72 of the countershaft 36 may generally cause the speed of both the directional shaft 34 and the countershaft 36 to decrease, as is generally understood.

Those skilled in the art will appreciate that by simultaneously engaging clutches 72 associated with two or more gears of the same shaft, a "quadruple" effect is provided whereby the gears in the shaft of transmission 24 One or more completely sudden stops. To avoid this, the clutch 72 associated with such a gear can be partially engaged by carefully modulating the pressure of the hydraulic fluid supplied to the clutch 72, thereby providing for the direction shaft 34 and intermediate shaft 36. Controlled deceleration. For example, as described above, the countershaft 36 may include both the engaged clutch 72 and the disengaged clutch 72 at the beginning of the shuttle shift. Thus, in order to partially engage the two clutches 72, the hydraulic pressure supplied to the previously engaged clutch 72 may be gradually lowered, while the hydraulic pressure supplied to the previously unengaged clutch 72 may be gradually increased. This modulation of the pressure of the hydraulic fluid supplied to the clutch 72 generally allows the rotational speed of the directional shaft 34 and countershaft 36 to be reduced in a controlled manner without causing sudden locking of the transmission 24, which would otherwise result in a localized "quad". squared” effect or controlled braking effect. As used herein, a clutch 72 is "partially engaged" or "partially disengaged" when the pressure of hydraulic fluid supplied to the clutch 72 is controlled to allow the clutch 72 to slip for a specified period of time before locking. ". For example, the pressure may be controlled to a minimum pressure that is required to carry the amount of torque required to decelerate one or more shafts at a specified rate.

It should also be understood that while the clutch 72 for the intermediate shaft 36 is being used to stop or otherwise slow the rotation of the directional shaft 34, the clutch 72 for the output shaft 38 can be completely disengaged so that the The countershaft 36 is disengaged from the output shaft 38 , thereby preventing the motion of the work vehicle 10 from being affected by any change in the rotational speed of the countershaft 36 . Alternatively, one or more of the clutches 72 for the output shaft 38 may be partially engaged, thereby providing an additional torque load to help stop or otherwise slow the directional shaft 34 and intermediate shaft 36 . Additionally, such partial engagement of the one or more clutches 72 of the output shaft 38 may also allow for effective reduction of the speed of the work vehicle 10 .

As an alternative to engaging the clutches 72 associated with two or more gears of the countershaft 36, the clutches 72 associated with two or more of the gears of the output shaft 38 may be engaged so that the direction Rotation of shaft 34 is stopped or otherwise slowed. For example, referring to the embodiment shown in FIG. 2 and assuming that at least one clutch 72 of the intermediate shaft 36 remains engaged, the clutches 72 associated with the third driven gear 68 and the fourth driven gear 70 of the output shaft 38 may be simultaneously engaged. ground to reduce the speed of the directional shaft 34 (and the speed of the intermediate shaft 36 and the output shaft 38). In such an embodiment, similar to the embodiments described above, the clutch 72 for the output shaft 38 may be partially engaged (eg, by modulating the pressure of hydraulic fluid supplied to the clutch 72 ) to provide the directional shaft 34, intermediate shaft 36 and controlled deceleration of output shaft 38. Furthermore, by using the clutch 72 of the output shaft 38 as a braking device, the speed of the work vehicle 10 can be simultaneously decelerated.

Still referring to FIG. 4 , in step 206 , after the rotational speed of the directional shaft 34 has decreased, the controller 102 may be configured to engage the clutch 72 associated with the opposing directional gear to allow the directional shaft 34 to rotate in the opposite direction. . For example, if work vehicle 10 is traveling in the forward direction when the shuttle shift begins, controller 102 may be configured to engage clutch 72 associated with reverse gear 54, thereby allowing input shaft 30 to travel in the opposite direction. Direction Turn direction axis 34. Similarly, if work vehicle 10 is traveling in a rearward direction when the shuttle shift begins, controller 102 may be configured to engage clutch 72 associated with first forward gear 46 or second forward gear 48, This allows the input shaft 30 to rotate the directional shaft 34 in the forward direction.

In one embodiment, it should be appreciated that the controller 102 may be configured to engage the clutch 72 associated with the opposing directional gear whenever (or after) rotation of the directional shaft 34 ceases. For example, controller 102 may be configured (via sensor 108 described above) to monitor the rotational speed of directional shaft 34 and may engage clutch 72 associated with the opposing directional gear when the rotational speed of directional shaft 34 decreases to zero. Alternatively, the controller 102 may be configured to monitor the rotational speed of the directional shaft 34 so that the clutch 72 associated with the opposing directional gear may be engaged when the rotational speed reaches a minimum speed threshold. For example, the minimum speed threshold may correspond to a rotational speed of the directional shaft 34 at which it is considered that the clutch 72 associated with the opposing directional gear can operate without overloading or overheating the clutch 72. The bottom is joined.

Additionally, as the clutch 72 associated with the opposite direction gear is engaged, the clutch 72 associated with the driven gear of countershaft 36 (and optionally, the clutch 72 associated with the driven gear of output shaft 38 ) Can be disengaged to allow the steering shaft 34 to pick up speed. Once the directional shaft 34 is turning at a sufficient speed, the clutch 72 (i.e., the clutch 72 associated with one of the driven gears of the intermediate shaft 36 and one of the driven gears of the output shaft 38) required to achieve the desired gear ratio clutches) may then be engaged by gradually increasing the pressure of hydraulic fluid supplied to such clutches 72, thereby fully engaging transmission 24 and allowing work vehicle 10 to travel in the new direction.

Referring back to FIG. 2 , to provide a specific example of the disclosed method 200 , it may be assumed that work vehicle 10 is engaged with clutch 72 for first forward gear 46 , first driven gear 64 , and third driven gear 68 engaged. The case initially travels in the forward direction. At the beginning of a shuttle shift (i.e., indicating that the direction of travel of work vehicle 10 is switching from a forward direction to a rearward direction), clutch 72 for first forward gear 46 may be disengaged, thereby causing the direction of travel to change. Shaft 34 is disengaged from input shaft 30 . Additionally, the clutch 72 for the third driven gear 68 may be fully or partially disengaged. Thereafter, the pressure of the hydraulic fluid supplied to the clutch 72 for the first driven gear 64 may gradually decrease, and the pressure of the hydraulic fluid supplied to the clutch 72 for the second driven gear 66 may gradually increase, The two clutches 72 of the intermediate shaft 36 are thereby partially engaged to allow the rotational speed of the steering shaft 34 to decrease. When the directional shaft 34 stops turning in its original direction (or when the rotational speed of the directional shaft 34 drops below a minimum speed threshold), the clutches for the first forward gear 64 and the second forward gear 66 of the countershaft 34 72 can be disengaged. Clutch 72 for reverse gear 54 may then be engaged to allow directional shaft 34 to rotate in the opposite direction. After the rotational speed of the directional shaft 34 has increased sufficiently, the appropriate clutches for the intermediate shaft 36 and the output shaft 38 may then be engaged in order to engage the transmission 24 in the desired gear ratio.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any involved methods. The patentable scope of the invention is determined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims provided they include structural elements that do not differ from the literal language of the claims, or provided they include equivalent structural elements with insubstantial differences from the literal language of the claims. That's it.

Claims (10)

1. for the method performing shuttle-type speed change by the actuating device of working truck, described Actuating device includes power shaft, countershaft and multiple driven shaft, and the plurality of driven shaft is defeated with described Entering axle and described countershaft extend substantially in parallel, described method includes:

The clutch making the first direction gear of the axis of orientation with the plurality of driven shaft be associated takes off Opening, described first direction gear configurations becomes to make described axis of orientation rotate along a first direction；

At least one the secondary driven shaft with the plurality of driven shaft is made at least by below step The clutch that two gears are associated engages to reduce the rotating speed of described axis of orientation:

The part maintaining the clutch previously engaged of at least one secondary driven shaft described connects Close, and

Connect to the previous unassembled clutch part of at least one secondary driven shaft described in making Close；And

After the rotating speed of described axis of orientation reduces, make the second direction gear with described axis of orientation The clutch being associated engages, in order to make described axis of orientation rotate along second direction.

Method the most according to claim 1, wherein, makes and the side of the plurality of driven shaft The throw-out-of clutch being associated to the first direction gear of axle includes: make with described axis of orientation to Front gear or a throw-out-of clutch being associated in backgear.

Method the most according to claim 1, wherein, described in described maintenance, at least one is secondary The part of the clutch previously engaged of driven shaft engage include being incrementally decreased be supplied to described The pressure of the hydraulic fluid of the clutch previously engaged, and wherein, make described at least one The previous unassembled clutch part ground of secondary driven shaft engages to include little by little increasing and is supplied to institute State the pressure of the hydraulic fluid of previous unassembled clutch.

Method the most according to claim 1, wherein, makes with the plurality of driven shaft extremely The clutch that at least two gear of a few secondary driven shaft is associated engages and includes: make with described The clutch that at least two gear of the jackshaft of multiple driven shafts is associated engages.

Method the most according to claim 4, also includes: when the rotation of described axis of orientation stops Time only, make the throw-out-of clutch that at least two gear with described jackshaft is associated.

Method the most according to claim 4, also includes: when with described first direction gear During the throw-out-of clutch being associated, make to be associated with the gear of the output shaft of the plurality of driven shaft Clutch part ground or fully disengage.

Method the most according to claim 1, wherein, makes with the plurality of driven shaft extremely The clutch that at least two gear of a few secondary driven shaft is associated engages and includes: make with described The clutch that at least two gear of the output shaft of multiple driven shafts is associated engages.

Method the most according to claim 1, wherein, makes and the second party of described axis of orientation Engage to clutch that gear is associated and include: when the rotation of described axis of orientation stops, making with The clutch that described second direction gear is associated engages.

Method the most according to claim 1, wherein, makes and the second party of described axis of orientation The clutch joint being associated to gear includes: when the rotating speed of described axis of orientation drops to minimum speed Time below degree threshold value, the clutch being associated with described second direction gear is made to engage.

Method the most according to claim 1, wherein, at least one secondary driven shaft described Including jackshaft and output shaft, described method also includes: relevant to described second direction gear After the clutch of connection is engaged, make and the gear of described jackshaft and the gear of described output shaft The clutch being associated engages.