Double-disconnect gearbox reverse switch with a disconnect synchronization device

Abstract

Gearbox reverse switch (110; 300) for reversing the direction of an output gear (122; 312) carried by an output shaft (112; 302), the gearbox reverse switch (110; 300) comprising: a return shaft (116; 306); a reverse clutch (132; 332) which is mounted around the return shaft (116; 306) and has engaged and disengaged states; and a reverse separation synchronizing device (340) which is mounted around the reverse shaft (116; 306) and has engaged and disengaged states; wherein, when the reverse clutch (132; 332) and the reverse disconnect synchronizer (340) are in the engaged states, the reverse shaft (116; 306) rotates the output gear (122; 312) in a reverse direction of rotation opposite to the direction of rotation of the output shaft (112; 302); and wherein, when the reverse separating synchronizing device (340) is in the disengaged state, the reverse clutch (132; 332) is separated from the output gear (122; 312), characterized by the fact that the reverse-separation synchronizing device (340) has an actuating piston (346) which moves a switching sleeve (348) in at least one axial direction of the transmission reverse switch (110; 300); wherein the actuating piston (346) has a first annular surface (390) with a first locking feature (388); wherein the switching sleeve (348) has a second annular surface (391) with a second locking feature (389) configured to engage with the first locking feature (388) of the actuating piston (346), wherein the switching sleeve (348) is connected to the actuating piston (346) by overlapping radial surfaces (392, 393) of the first and second locking features (388, 389) when the first and second annular surfaces (390, 391) are arranged concentrically.

Description

AREA OF REVELATION

[0001] The present disclosure relates generally to transmissions with a reverse switch for changing the direction of a vehicle. GENERAL STATE OF DISCLOSURE

[0002] Transmissions are used in vehicles and work machines, such as agricultural, construction, off-road, and industrial equipment. Transmissions used in work machines typically provide a wide range of gear ratios for propelling the vehicle. A transmission may include a reverse switch for changing the vehicle's direction. The reverse switch may be located near the transmission output. In some earlier designs, a balance shaft reverse switch rotates at high speeds when the vehicle is operating at high forward speeds. This can cause excessive air movement in the reverse clutch. It can also cause gyroscopic flutter, in which the friction disc or separator plate becomes dynamically unstable, creating resistance in the clutch. This resistance can cause the disengaged clutch to experience thermal failure.In other previous designs, a synchronized reverse switch goes into neutral when switching between forward and reverse gears, causing a pause in acceleration.

[0003] From DE 10 2017 202 764 A1 a gearbox with a reversing device is also known, which forms the preamble of claim 1. SUMMARY OF THE REVELATION

[0004] This summary is provided to introduce a selection of concepts that are further described in detail in the following description and accompanying drawings. This summary is neither intended to identify key or main features of the accompanying claims, nor is it intended to be used as an aid in determining the scope of protection of the accompanying claims.

[0005] According to the present invention, a gearbox reverse switch with the features of claim 1 is provided.

[0006] According to a further aspect of the present invention, a transmission reverse switch for reversing the direction of an output gear carried by an output shaft can comprise a reverse shaft extending along an axis of rotation, reverse gears mounted around the reverse shaft, a reverse clutch mounted around the reverse shaft with engaged and disengaged states and connecting a reverse gear to the reverse shaft in the engaged state, and a reverse disconnect synchronizer having engaged and disengaged states and connecting another reverse gear to the reverse shaft in the engaged state. The reverse disconnect synchronizer comprises a hub mounted around the reverse shaft and defining a piston chamber. An actuating piston in the piston chamber is driven by fluid pressure in at least one direction along the axis of rotation of the reverse shaft.A shift sleeve is mounted on the actuating piston and engaged with the return gear in an engaged position. When the reverse clutch and the reverse disengagement synchronizer are engaged, the return shaft rotates the output gear in the opposite direction to the rotation of the output shaft. When the reverse disengagement synchronizer is disengaged, the reverse clutch is disconnected from the output gear.

[0007] According to a further aspect of the present invention, a transmission reverse switch for reversing the direction of an output gear carried by an output shaft may comprise a reverse shaft extending along an axis of rotation, reverse gears mounted around the reverse shaft, a reverse clutch mounted around the reverse shaft with engaged and disengaged states and connecting a reverse gear to the reverse shaft in the engaged state, and a reverse disconnect synchronizer having engaged and disengaged states and connecting another reverse gear to the reverse shaft in the engaged state.The reverse-disengaging synchronizer comprises an actuating piston with a first annular surface having a first locking feature and a shift sleeve that is engaged with the reverse gear in an engaged state and has a second annular surface with a second locking feature configured to engage with the first locking feature of the actuating piston. The shift sleeve is connected to the actuating piston by overlapping radial surfaces of the first and second locking features when the first and second annular surfaces are concentric. When the reverse clutch and the reverse-disengaging synchronizer are in the engaged states, the reverse shaft rotates the output gear in the opposite direction to the rotation of the output shaft.When the reverse separation synchronizer is in the disengaged state, the reverse clutch is disconnected from the output gear.

[0008] These and other features will become apparent from the following detailed description and the accompanying drawings, in which various features are shown and described for illustrative purposes. The present disclosure may have further and different configurations, and its various details may be modified in various other aspects without altering the scope of protection afforded by the present disclosure. Accordingly, the detailed description and the accompanying drawings are to be considered illustrative and not limiting or restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The detailed description of the drawings refers to the attached figures, in which: Fig. 1 a perspective section view of a gearbox according to an embodiment; Fig. 2 a perspective rear view of a gearbox according to an embodiment; Fig. 3 a side sectional view of a reverse switch according to one embodiment; Fig. 4 is a side sectional view of a reverse switch, which represents the power path for the forward mode according to one embodiment; Fig. 5 is a lateral sectional view of a reverse switch, which represents the power path for the reverse mode according to one embodiment; Fig. 6 is a schematic diagram of a control strategy for a transmission according to one embodiment; Fig. 7 is a flowchart that illustrates a method for switching between forward and reverse directions in a gear reverse switch according to one embodiment; Fig. 8 is a flowchart that illustrates a method for switching between reverse and forward directions in a gear reverse switch according to one embodiment; Fig. 9 is a side sectional view of a reverse switch, which represents the power path for the forward mode according to a second embodiment; Fig. 10 is a side sectional view of a reverse switch, which represents the power path for the reverse mode according to the second embodiment; Fig. 10A is an enlarged view of an exemplary separation synchronization arrangement for a backstop according to the second embodiment; Fig. 10B a detailed view of the area 10B-10B of an interface between an actuating piston and a switching sleeve of the in Fig. The separation synchronization device shown in 10A is; Fig. 11 is a schematic diagram of a control system for a gearbox according to the second embodiment; Fig. 11A is a schematic diagram of a control strategy for a gearbox according to the second embodiment; Fig. 12 is a flowchart that represents an exemplary start sequence for a gearbox reverse switch according to the second embodiment; Fig. 13 is a flowchart that represents an exemplary method for switching between forward and reverse directions in a gear reverse switch according to a second embodiment; Fig. 13A is a flowchart that represents an exemplary logic subroutine for controlling the intervention of a separation synchronization device in the procedure of Fig. 13 represents; Fig. 14 is a flowchart that represents an exemplary method for switching between reverse and forward directions in a gear reverse switch according to a second embodiment; Fig. 14A is a flowchart that represents an exemplary control logic subroutine for controlling the engagement or disengagement of the separation synchronization device in the procedure of Fig. 14 represents; and Fig. 14B is a flowchart that shows an exemplary control logic subroutine for detecting an error during the operation of the separation synchronization device in the procedure of Fig. 14 represents.

[0010] The same reference symbols are used to denote identical elements in the different figures. DETAILED DESCRIPTION

[0011] The embodiments disclosed in the drawings above and the following detailed description are not intended to be exhaustive, nor are they intended to limit the disclosure to these embodiments. Rather, there are several variations and modifications that can be made without deviating from the scope of protection of the present disclosure.

[0012] Fig. Figure 1 shows, for example, a transmission 100 for a vehicle or a working machine, such as a tractor. The present disclosure also applies to other powered or motorized vehicles, machines, or equipment. The transmission 100 comprises a housing 102, which forms an interior that provides a housing for one or more transmission components, including, but not limited to, shafts, gears, clutches, and synchronizing devices. The transmission 100 may include a transmission reverse switch 110, which switches the transmission output between forward and reverse gear. The reverse switch 110 may be integrated with the transmission 100 or separate from it.

[0013] The Fig. 2 and Fig. Figure 3 shows a gearbox 100 with a reverse switch device 110, which may include one or more of the following components. The gearbox 100 may include an output shaft 112, an idle shaft 114, and a countershaft 116, which are rotatably connected to the gearbox housing 102. The gearbox 100 may include a first reverse gear 120 and an output gear 122, which is arranged on or supported by the output shaft 112. The output gear 122 is functionally connected to the drivetrain of a vehicle, providing power to a ground-engaging device, such as wheels or rails. The gearbox may include an idle gear 124, which is arranged on or supported by the idle shaft 114. The gearbox may include a second reverse gear 126 and a third reverse gear 128, which are arranged on or supported by the countershaft 116.The transmission 100 can include a forward clutch 130 that functionally connects or couples the output gear 122 to the output shaft 112 in an engaged position or state. The forward clutch 130 can be connected to or mounted around the output shaft 112.

[0014] The transmission 100 can include a reverse clutch 132 that functionally connects or couples the second reverse gear 126 to the countershaft 116 in an engaged position or state. The reverse clutch 132 can be connected to or mounted around the countershaft 116. In another embodiment, the reverse clutch 132 functionally connects or couples the first reverse gear 120 to the output shaft 112. The reverse clutch 132 can be connected to or mounted around the output shaft 112. In this embodiment, the output shaft 112 rotates independently of the first reverse gear 120, the idler gear 124, and the idler shaft 114 when the reverse clutch 132 is disengaged. The gearbox 100 can include a disconnect clutch 134 which functionally connects or couples the third return gear 128 to the countershaft 116 in an engaged position or engaged state.The disengaging clutch 134 can be connected to or mounted around the countershaft 116. The first reverse gear 120 is engaged with or toothed to the idle gear 124, which is engaged with or toothed to the second reverse gear 126. The third reverse gear 128 is engaged with or toothed to the output gear 122. The transmission 100 can include a countershaft brake 136, which reduces or stops the rotation of the countershaft 116 in an engaged position or state. In some embodiments, the countershaft brake 136 can prevent or stop the rotation of the countershaft 116. This can prevent or stop the reverse clutch 132 from rotating when the countershaft brake 136 is engaged.

[0015] Fig. Figure 4 shows a power path or flow for a forward mode F through the reverse switch device 110. In forward mode F, the forward clutch 130 is engaged, causing the output gear 122 to rotate with the output shaft 112. The countershaft brake 136 is engaged, hindering or stopping the rotation of the countershaft 116, and the reverse clutch 132 and the disconnect clutch 134 are disengaged. When the countershaft brake 136 is engaged, it can also hinder or stop the rotation of the reverse clutch 132. The idle shaft 114 rotates in the opposite direction to the output shaft 112 based on the ratio of the first return gear 120 to the idle gear 124. The second return gear 126 rotates around the countershaft 116 in a direction opposite to the idle shaft 114 based on the ratio of the idle gear 124 to the second return gear 126.At slow forward speeds, the countershaft brake 136 can be disengaged and the disconnect clutch 134 engaged, causing the countershaft 116 to rotate in the opposite direction to the output shaft 112, based on the ratio of the output gear 122 to the third return gear 128. In some embodiments, the slow forward speeds are at or below approximately 5 km / h, 4 km / h, 3 km / h, 2 km / h, or 1 km / h.

[0016] Fig. Figure 5 shows a power path or flow for a reverse mode R through the reverse switch device 110. In reverse mode R, the reverse clutch 132 and the disconnect clutch 134 are engaged, causing the output gear 122 to rotate in the opposite direction to the output shaft 112. The forward clutch 130 and the countershaft brake 136 are disengaged. The output gear 122 rotates in the opposite direction to the countershaft 116 based on the ratio of the third reverse gear 128 to the output gear 122. The countershaft 116 rotates in the opposite direction to the idle shaft 114 based on the ratio of the idle gear 124 to the second reverse gear 126. The idle shaft 114 rotates relative to the output shaft 112 based on the ratio of the first reverse gear 120 to the idle gear 124. Consequently, the countershaft 116 rotates in the same direction as the output shaft 112.

[0017] Fig. Figure 6 shows a control strategy for a transmission that can be implemented in one or more of the embodiments described herein and illustrated in the various figures. When the transmission is in reverse mode R, the reverse clutch 132 and the disengage clutch 134 are engaged, and the forward clutch 130 and the countershaft brake 136 are disengaged. When switching between reverse mode R and forward mode F, events can occur in the following sequence: the reverse clutch 132 is disengaged, the forward clutch 130 is engaged, the disengage clutch 134 is disengaged, and the countershaft brake 136 is engaged. The reverse clutch 132 and the forward clutch 130 can be engaged and disengaged at slow reverse speeds, slow forward speeds, or when the vehicle is stationary.

[0018] When the transmission is in forward mode F, the forward clutch 130 and the countershaft brake 136 are engaged, and the reverse clutch 132 and the disconnect clutch 134 are disengaged. When switching between forward mode F and reverse mode R, the following sequence of events can occur: the countershaft brake 136 is disengaged, the disconnect clutch 134 is engaged, the forward clutch 130 is disengaged, and the reverse clutch is engaged. The disconnect clutch 134 and the countershaft brake 136 can be engaged and disengaged at slow forward speeds or when the vehicle is stationary.

[0019] Fig. Figure 7 shows a flowchart for a method for switching between a forward mode and a reverse mode in a gear reverse switch according to an embodiment that may be implemented in one or more of the embodiments described herein and illustrated in the figures. The method starts with step 200.

[0020] At step 202, the transmission is in forward mode F with the forward clutch 130 and the countershaft brake 136 in the engaged positions.

[0021] At step 204, the transmission receives a command to switch from forward mode F to reverse mode R.

[0022] In step 206, the countershaft brake 136 is disengaged, allowing the countershaft 116 to rotate.

[0023] In step 208, the disconnecting clutch 134 is engaged, which detachably connects or couples the third return gear 128 to the countershaft 116, causing the countershaft 116 to rotate in the opposite direction to the output shaft 112 based on the engagement of the third return gear 128 with the output gear 122.

[0024] In step 210, the forward clutch 130 is disengaged, which separates the output wheel 122 from the output shaft 112, allowing the output wheel 122 to rotate independently of the output shaft 112.

[0025] In step 212, the reverse clutch 132 is engaged, which detachably connects or couples the second reverse gear 126 to the countershaft 116, causing the countershaft 116 to rotate in the same direction as the output shaft 112 based on the engagement of the first reverse gear 120, which is mounted on the output shaft 112, with an idler gear 124, which is mounted on an idler shaft 114, and the engagement of the idler gear 124 with the second reverse gear 126.

[0026] In an alternative step 212, the reverse clutch 132 is engaged, which detachably connects or couples the first return gear 120 to the output shaft 112, causing the countershaft 116 to rotate in the same direction as the output shaft 112 based on the engagement of the first return gear 120 with the idler gear 124, which is mounted on the idler shaft 114, and the engagement of the idler gear 124 with the second return gear 126, which is mounted on the countershaft 116.

[0027] Step 214 completes the procedure for switching between a forward mode and a reverse mode in a gear reverse switch according to one embodiment. In other embodiments, one or more of these steps or operations can be omitted, repeated, or rearranged and still achieve the desired results.

[0028] Fig. Figure 8 shows a flowchart for a method for switching between a reverse mode and a forward mode in a gear reverse switch according to an embodiment that may be implemented in one or more of the embodiments described herein and illustrated in the figures. The method starts with step 200.

[0029] At step 202, the transmission is in reverse mode R with the reverse clutch 132 engaged and the disconnect clutch 134 is in the engaged positions.

[0030] At step 204, the transmission receives a command to switch from reverse mode R to forward mode F.

[0031] At step 206, the reverse clutch 132 is disengaged, which separates the second reverse gear 126 from the countershaft 116 or the first reverse gear 120 from the output shaft 112, allowing the countershaft 116 to rotate independently of the output shaft 112.

[0032] At step 208, the forward clutch 130 is engaged, which detachably connects or couples the output wheel 122 to the output shaft 112, causing the output wheel 122 to rotate with the output shaft 112.

[0033] In step 210, the disconnect clutch 134 is disengaged, which separates the third return wheel 128 from the countershaft 116, allowing the countershaft 116 to rotate independently of the output wheel 122.

[0034] In step 212, the countershaft brake 136 is engaged, thereby slowing down or stopping the rotation of the countershaft 116. In some embodiments, the countershaft brake 136 can then prevent the countershaft 116 from rotating or stop its rotation altogether.

[0035] Step 214 completes the procedure for switching between a reverse mode and a forward mode in a gear reverse switch according to one embodiment. In other embodiments, one or more of these steps or operations can be omitted, repeated, or reversed and still achieve the desired results.

[0036] Step 214 completes the procedure for switching between a reverse mode and a forward mode in a gear reverse switch according to one embodiment. In other embodiments, one or more of these steps or operations can be omitted, repeated, or reversed and still achieve the desired results.

[0037] A further embodiment of the transmission reverse switch disclosed herein will now be described. It is understood that this embodiment of the transmission reverse switch can be installed in a transmission for a vehicle or a machine (or other equipment). For example, the transmission 100 can incorporate this embodiment of the transmission reverse switch and have the same configuration as described above. Fig. 1 and Fig. 2, unless otherwise specified, including a housing 102 forming an interior that provides a mounting for one or more transmission components, including, but not limited to, shafts, gears, clutches, and synchronizing devices. As described in the preceding embodiment, this embodiment of the transmission reverse switch can be used to switch the transmission output between forward and reverse gears and can be integrated with or separate from the transmission 100.

[0038] The Fig. 9 and Fig. Figure 10 shows a reverse switch device 300, which may include one or more of the following components, including an output shaft 302, an idle shaft 304, and a reverse shaft in the form of a countershaft 306 extending along a pivot axis “A”, each rotatably connected to the gearbox housing 102. The gearbox 100 or the reverse switch device 300 may include a first reverse gear 310 and an output gear 312 arranged on or supported by the output shaft 302. The output gear 312 may be functionally connected to the drive train of a vehicle, providing power to a ground-engaging device, such as wheels or rails. The gearbox 100 or the reverse switch device 300 can comprise an idle wheel 316 arranged or mounted on the idle shaft 304, as well as a second reverse wheel 318 and a third reverse wheel 320 arranged or mounted on the countershaft 306.The gearbox 100 or the reverse switch device 300 may include a forward clutch 330 that functionally connects or couples the output gear 312 to the output shaft 302 in a disengaged position or condition. The forward clutch 330 may be connected to or mounted around the output shaft 302. The gearbox 100 or the reverse switch device 300 may include a reverse clutch 332 that functionally connects or couples the second reverse gear 318 to the countershaft 306 in a disengaged position or condition. As described in the previous embodiment, in this embodiment the reverse clutch 332 can be connected to or mounted around the countershaft 306, so that the countershaft 306 rotates independently of the first reverse gear 310, the idle wheel 316 and the idle shaft 304 when the reverse clutch 332 is disengaged.In another embodiment, the reverse clutch 332 functionally connects or couples the first reverse gear 310 to the output shaft 302, in which case the reverse clutch 332 can be connected to or mounted around the output shaft 302, so that the output shaft 302 rotates independently of the first reverse gear 310, the idle gear 316 and the idle shaft 304 when the reverse clutch 332 is disengaged.

[0039] The transmission 100 or the reverse switch device 300 of this embodiment comprises a disconnect synchronizer 340 that functionally connects or couples the third reverse gear 320 to the countershaft 306 in an engaged position or engaged state. The disconnect synchronizer 340 can be connected to or mounted around the countershaft 306. The first reverse gear 310 is engaged with or toothed to the idler gear 316, which is engaged with or toothed to the second reverse gear 318. The third reverse gear 320 is engaged with or toothed to the output gear 312.In this embodiment, the transmission 100 or the reverse switch device 300 can omit a countershaft brake that was used in the previous embodiment to reduce or stop the rotation of the countershaft 306 in an engaged position or state, thereby hindering or stopping the rotation of the reverse clutch 332. Alternatively, a countershaft brake, such as the countershaft brake 136, can be incorporated into the transmission 100 or the reverse switch device 300 of this embodiment and used for the aforementioned purpose.

[0040] Fig. Figure 9 shows a power path or flow for a forward mode F through the reverse switch device 300. In forward mode F, the forward clutch 330 is engaged, causing the output gear 312 to rotate with the output shaft 302 and the reverse clutch 332 (and temporarily the disconnect synchronizing device 340) to be disengaged. (The countershaft brake, if present, can be engaged, preventing the countershaft 306 and the reverse clutch 332 from rotating.) The idle shaft 304 rotates in the opposite direction to the output shaft 302 based on the ratio of the first reverse gear 310 to the idle gear 316. The second reverse gear 318 rotates around the countershaft 306 in a direction opposite to that of the idle shaft 304 based on the ratio of the idle gear 316 to the second reverse gear 318.At slow forward speeds, the disengaging synchronizer 340 can be engaged, causing the countershaft 306 to rotate in the opposite direction to the output shaft 302, based on the ratio of the output gear 312 to the third return gear 320. (The countershaft brake, if present, would be disengaged.) As in the preceding embodiment, the slow forward speeds can be at or below approximately 5 km / h, 4 km / h, 3 km / h, 2 km / h, or 1 km / h.

[0041] Fig. Figure 10 shows a power path or flow for a reverse mode R through the reverse switch device 300. In reverse mode R, the reverse clutch 332 and the disconnect synchronizer 340 are engaged, causing the output gear 312 to rotate in the opposite direction to the output shaft 302. The forward clutch 330 (and, if present, the countershaft brake) is disengaged. The output gear 312 rotates in the opposite direction to the countershaft 306 based on the ratio of the third reverse gear 320 to the output gear 312. The countershaft 306 rotates in the opposite direction to the idle shaft 304 based on the ratio of the idle gear 316 to the second reverse gear 318. The idle shaft 304 rotates relative to the output shaft 302 based on the ratio of the first reverse gear 310 to the idle gear 316. Consequently, the countershaft 306 rotates in the same direction as the output shaft 302.

[0042] The disengaging synchronizer can be configured in various ways. Certain well-known synchronizers, for example, are engaged and disengaged by the movement of a shift rail and fork assembly, which can be actuated manually or semi-automatically. In general, in such cases, one or more fork elements move along one or more shift rails to move a synchronizer element into engagement with a gear of the transmission (e.g., by the synchronizer teeth meshing with the gear teeth). The synchronizer is coupled to the shaft for co-rotation, and thus the engagement of the synchronizer with the gear also couples the gear to the shaft for co-rotation, thereby placing the gear within the rotational power (or torque) path from the power source (e.g., a motor).A locking element can be arranged between the synchronizing element and the gear to prevent displacement until its splines are timed to align with the splines of the gear. The engagement and disengagement of the gear can thus be largely, if not entirely, mechanical in the sense that the shift rail moves the synchronizing device back and forth relative to the gear. Certain other known synchronizing devices have been developed that use hydraulic force to couple gear sets to the output shaft. Some of these use a shift rail and fork arrangement similar to the one described above, although the shift fork movement is hydraulically effected. Other systems eliminate the shift rail and fork arrangement altogether. Instead, these systems circulate hydraulic fluid into chambers that drive pistons to move shift sleeves into engagement with the gears.A shift sleeve is disengaged from a gear by venting a pressure chamber, allowing one or more return springs acting on the piston to move the shift sleeve back to a neutral position. Reverse gear can also be engaged by the spring exerting the engagement force on the shift sleeve, which is then hydraulically disengaged. Further synchronizing devices can be used that are fully electro-hydraulically operated, so that the movement of the shift sleeves into both the engaged and disengaged positions is achieved by hydraulic force. Furthermore, the disengaging synchronizing device can be single- or double-sided, with the option of engaging one or two gears with the shaft.

[0043] As an example, this embodiment of the reverse switch device 300 is described, wherein the disconnect synchronizer 340 is configured as a single-sided (or "semi-") forkless synchronizer that is hydraulically engaged and disengaged by spring force. Although not shown, it is understood that the work vehicle, the transmission 100, or the reverse switch device 300 includes or is functionally connected to an electro-hydraulic system with one or more hydraulic pumps and electro-hydraulic valves, which are operated by one or more controllers for controlling operating modes of the transmission 100 or the reverse switch device 300.In general, the exemplary separating synchronizing device 340 can be operated to selectively couple the third return gear 320 with the countershaft 306 and thereby the reverse clutch 332 with the output gear 312, depending on the control logic associated with the operating mode of the transmission, as mentioned above and described in detail below.

[0044] Fig. Figure 10A shows an exemplary semi-forkless hydraulic separating synchronizer 340. The separating synchronizer 340 can be connected to or mounted on the countershaft 306 by a drum 342 or the like, which is continuously mounted on the countershaft 306 for co-rotation, for example, via the interlocking splines or other splined or polygonal sections of the countershaft 306 and the drum 342. The drum 342 defines a stepped annular piston chamber 344 into which hydraulic fluid can be directed in a controlled manner to move an actuating piston 346 along the axis of rotation A. The actuating piston 346 has a stepped outer circumference to match the piston chamber 344 and is sealed at both stepped diameters (via O-rings or the like).The shift sleeve 348 has an axially toothed inner diameter that is connected to an axially toothed circumference (circumferential or circumferential segments) of a hub 350, which has an axially toothed inner diameter that engages with splines on the countershaft 306. The hub 350 has open areas in which retaining spring detent assemblies 352 (each with a spring 354, a ball 356 and a ball sleeve 358) are coupled to the hub 350 (e.g. by retaining pins of the ball sleeve 358 or retaining pins attached to it). The balls 356 of the spring detent arrangements 352 run in an annular groove 368 in the toothed inner diameter of the shift sleeve 348 and exert a spring force on a locking ring 370 when the shift sleeve 348 is initially switched axially relative to the hub 350.An annular body of the locking ring 370 is arranged axially within an annular, open-face pocket 372 in the hub 350, between the third return wheel 320 and the hub 350. The locking ring 370 rotates with the hub 350 but can slide slightly or rotate relative to the hub 350, for example, by means of a pin and slot connection (not shown) between the locking ring 370 and the hub 350. The locking ring 370 has a tapered inner circumference that is connected to a conical ring or cone 374, which may be attached to the third return wheel 320 or formed integrally with it. In certain embodiments, the tapering of the locking ring 370 or the gear cone 374 may include a thin friction ring 360 (e.g. by bonding) to aid in the production of a robust friction connection, and cooling grooves (not shown) may be formed in the friction ring 360 to aid in heat dissipation.The locking ring 370 also has an axially toothed outer ring (or ring segments) that engages with the toothed inner diameter of the shift sleeve 348. The drum 342, the actuating piston 346, the shift sleeve 348, the hub 350, and the locking ring 370 can each be an arrangement of parts or a single monolithic structure. The movement of the actuating piston 346 is preloaded by one or more springs 380 (e.g., disc springs) that are axially mounted within the drum 342 between the actuating piston 346 and the hub 350.

[0045] The locking ring 370 serves to reduce or prevent "improper gear engagement" by blocking the engagement of the splines of the shift sleeve 348 with the splines of the third return gear 320 when the projections of the splines of the shift sleeve 348 are not synchronized or rotationally aligned with the spline recesses of the third return gear 320. In particular, when the shift sleeve 348 is moved axially towards the third return gear 320 by the actuating piston 346, the groove 368 in the toothed inner diameter of the shift sleeve 348 presses against the balls 356 to compress the springs 354 and thereby apply an axial force against a radial surface of the locking ring 370. The axial force is an axial component of the radial force exerted on the springs 354 by the engagement of the balls 356 and the curved wall of the groove 368.The springs 354 press the locking ring 370 against the third return gear 320, specifically the conical surface of the locking ring 370 and the gear cone 374. Initially, there is a difference between the rotational speed of the locking ring 370 (and thus of the remainder of the disengaging synchronizer 340 and the countershaft 306) and the third return gear 320. The spring force that biases the locking ring 370 against the third return gear 320, together with the speed difference, generates a torque on the locking ring 370, causing it to rotate slightly relative to the hub 350 (e.g., until the pin(s) engage the end(s) of the slot(s)), after which it continues to rotate with the hub 350. This positions the locking ring 370 in a position that restricts the axial travel of the shift sleeve 348.As the shift sleeve 348 continues to move, tapered tooth tips at the ends of the splines of the shift sleeve 348 contact tapered tooth tips of the splines of the locking ring 370. The angled tips collide and generate a rotational force or torque on the locking ring 370, which tends to push the locking ring 370 away from the path of the splines of the shift sleeve 348 and release it. This torque is resisted by the torque from the engagement of the locking ring 370 (or the friction ring 360) and the gear cone 374, which is still rotating at a different speed. When the third return wheel 320 is accelerated or decelerated to match the speed of the separating synchronizing device 340, the frictional torque is transferred via the gear cone 374 to allow the splined teeth of the shift sleeve 348 to pass between the splined teeth of the locking ring 370.If the third return gear 320 is not properly timed with the locking ring 370 as the shift sleeve 348 continues to move, the tooth contact between the shift sleeve 348 and the third return gear 320 generates a torque that slightly indexes the locking ring 370 (as enabled by the pin and slot connection(s)) until the splines of the shift sleeve 348 can fully engage with the splines of the third return gear 320. The splines of the shift sleeve 348 simultaneously mesh with the splines of the shift sleeve of the third return gear 320 and the hub 350, thereby engaging the third return gear 320 with the countershaft 306. When the pressure in the piston chamber 344 is sufficiently vented, the springs 380 will return the actuating piston 346 and the shift sleeve 348 to the disengaged position, in which the third return wheel 320 is disengaged from the countershaft 306.

[0046] Fig. Figure 10B shows that the actuating piston 346 engages directly with the switching sleeve 348 along a locking interface formed between the locking features 388, 389 in the annular surfaces 390, 391 of the actuating piston 346 and the switching sleeve 348. The switching sleeve 348 is connected to the actuating piston 346 by overlapping radial surfaces 392, 393 of the locking features 388, 389 when the annular surfaces 390, 391 are arranged concentrically. The coupling of the locking features 388, 389 can connect the switching sleeve 348 with relative freedom of rotation to the actuating piston 346 in order to enable angular indexing (e.g. 2-3 degrees) of the switching sleeve 348 relative to the actuating piston 346 by providing a small difference (e.g. half a millimeter) in the radial dimensions.The radial surfaces 392, 393 of the locking features 388, 389 interlock to prevent separation of the shift sleeve 348 from the actuating piston 346 in at least one axial direction, such as during the disengaged position. The radial surfaces 392, 393 of the locking features 388, 389 can be oriented substantially perpendicular to the axis of rotation A of the countershaft 306 to provide a flat surface and a sharp corner for establishing and maintaining contact between the actuating piston 346 and the shift sleeve 348 during resetting. Furthermore, the annular surfaces 390, 391 of the actuating piston 346 and the switching sleeve 348 adjacent to the radial surfaces 392, 393 of the locking features 388, 389 can include undercut relief recesses 394, 395.In various embodiments, the actuating piston 346 and the switching sleeve 348 can be made of the same or different materials and using the same or different processes. For example, the switching sleeve 348 can be heat-treated carbonized steel, and the actuating piston 346 can be a quenched and hardened forged steel without heat treatment. Furthermore, the actuating piston 346 and the switching sleeve 348 can be mounted directly to one another without fasteners or other intervening components, such as by an interference fit, to engage with the locking features 388, 389. As an example, the actuating piston 346 can be pressed onto the switching sleeve 348, in which case the inner annular surface 390 of the actuating piston 346 overlaps and engages with the outer annular surface 391 of the switching sleeve 348.The actuating piston 346 and the switching sleeve 348 can each include chamfered leading edges 396, 397 (which convert axial forces into radial forces to open the actuating piston 346), and the actuating piston 346 can include one or more peripheral notches 398 on the chamfered leading edge 396 of its annular surface 390 to facilitate bending and reduce stress during the press fit process below the material yield. It is understood that other configurations are possible and that the overlapping and coupling of components can be reversed compared to that described.

[0047] Fig. Figure 11 schematically shows a control hardware and data flow for a gearbox that can be implemented with respect to the embodiment of the return switch device 300. Fig. 11A shows a tax strategy for a tax system 400 of Fig. 11. When the transmission 100 is in reverse mode R, the reverse clutch 332 and the synchronizing unit 340 are engaged, and the forward clutch 330 (and, if fitted, the countershaft brake) is disengaged. When switching between reverse mode R and forward mode F, events can generally occur in the following sequence: the reverse clutch 332 is disengaged, the forward clutch 330 is engaged, the synchronizing unit 340 is disengaged (and, if fitted, the countershaft brake is engaged). The reverse clutch 332 and the forward clutch 330 can be engaged and disengaged at slow reverse speeds, slow forward speeds, or when the vehicle is stationary.When the transmission is in forward mode F, the forward clutch 330 (and, if fitted, the countershaft brake) is engaged and the reverse clutch 332 (and sometimes the synchronizing unit 340) is disengaged. When switching between forward mode F and reverse mode R, events can generally occur in the following sequence: each countershaft brake is disengaged, the synchronizing unit 340 is engaged, the forward clutch 330 is disengaged, and the reverse clutch 332 is engaged. The synchronizing unit 340 (and, if fitted, the countershaft brake) may engage and disengage at slow forward speeds or when the vehicle is stationary.

[0048] The control system 400 comprises a controller for a vehicle, transmission, or reverse switch device 402 (or multiple controllers), which may be configured as a computer device with associated processing devices and memory architectures, as a hard-wired computer circuit (or circuits), as a programmable circuit, as a hydraulic, electrical, or electrohydraulic controller, or in some other way to perform various computer-based functions and control functions with respect to the transmission 100 or the reverse switch device 300. The controller 402 and its various modules are each schematically represented by a single block. However, the controller 402 and its modules may comprise any number of processing devices, which can be distributed and interconnected using various communication protocols and memory architectures.Additionally, each block shown may contain one or more additional components beyond those specified (e.g., a block representing a particular clutch or synchronizer may contain an associated electro-hydraulic control valve). As used herein, the term "module" refers to any hardware, software, firmware, electronic control component, processing logic, and / or processing device, individually or in any combination, including, without limitation: an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group processor), and memory executing one or more software or firmware programs, a combinational logic circuit, and / or other suitable components providing the described functionality.

[0049] The 402 controller can be configured to receive input signals in various formats (e.g., hydraulic signals, voltage signals, current signals, etc.) and to output command signals in various formats (e.g., hydraulic signals, voltage signals, current signals, mechanical movements, etc.). The 402 controller can be connected electronically, hydraulically, mechanically, or otherwise to various other systems or devices of the vehicle, the transmission, or the reverse switch device.The control system of a work vehicle 402 can, for example, be in electronic or hydraulic connection with various power controllers, sensors, and other devices inside (or outside) the vehicle, the transmission, or the reverse switch device, including various timers or clock generators 410 and various sensors, such as speed sensors 412, 413, 414, and a pressure sensor 416, for determining the absolute or relative speeds or pressures of various components of the reverse switch device 300 (e.g., the speed of the third reverse gear 320 with respect to the countershaft 306 or various components of the disconnect synchronizer that rotate in the same direction) and an operator control 418. Various other devices and sensors (e.g., temperature sensors) can be incorporated into the control system 400 and used by the control system 402 to process the disclosed control logic.The various devices and sensors provide input or observation conditions associated with the transmission 100 or the reverse switch device 300 and generate input signals or data that are transmitted to the controller 402. The controller 402 may be located on board the vehicle or at various remote locations. The controller 402 uses input from the various devices and sensors to control the engagement state of various components of the transmission 100 or the reverse switch device 300, including a drive clutch 420, the forward clutch 330, the reverse clutch 332, the disconnect synchronizer 340, and a parking brake or park mode controller 430.The drive coupling 420 can be a single coupling or a combination of several couplings arranged between the motor and the output shaft 302 to control the power from the motor in one of various operating modes of the transmission 100. Various other devices (e.g., a countershaft brake) can be controlled by the control system 400.

[0050] In the illustrated embodiment, the controller 402 comprises various embedded modules or submodules that process the input signals or data uniformly or collectively and provide output control commands for the devices of the transmission 100 or the reverse switch device 300 according to the control logic of this disclosure. As can be seen, the modules or submodules shown may be combined and / or further partitioned in other embodiments. In particular, the exemplary controller 402 comprises a device control (DC) module 440, which is connected to the various components and devices of the transmission 100 or the reverse switch device 300, namely, for example, the drive clutch 420, the forward clutch 330, the reverse clutch 332, the disconnect synchronizer 340, and the parking brake or parking mode control 430.The DC module 440 communicates with a Disconnect Synchronizer Engagement (DSE) module 450, which in turn communicates with one or more of a Timer Module 460, a Speed ​​Module 470, a Pressure Module 480, and a Value Data Storage Module 490. The DSE module 450 also communicates with a User Interface (UL) module 452, which receives input from the operator control unit 418. As shown, the timer module 460 receives input data from the clock generator 410, the speed module 470 receives sensor input data from the speed sensors 412, 413, 414, and the pressure module receives sensor input data from the pressure sensor 416. The value data memory 490 is a memory module that contains various stored values ​​which are used by the controller 402 via one or more of its modules to execute control logic according to one or more current or detected parameters.The value data memory 490 can contain one or more speed, pressure, time, or other threshold values ​​that the controller 402 can evaluate with respect to actual or recorded parameters according to the stored control logic, which may be stored in the various modules or submodules, or other on-board or remote memory modules. An exemplary control logic, executed by the controller 402 with respect to the gearbox 100 or the reverse switch device 300, is now described.

[0051] Fig. Figure 12 shows a flowchart for a control logic by which the control system 400 implements a method for executing a start mode or start sequence for the gearbox 100 or the reverse switch device 300 according to one embodiment. The start sequence generally applies energy to the disconnect synchronizer 340 and thereby torque to its engagement components (e.g., shift sleeve, locking ring) to facilitate engagement with the third reverse gear 320. It should be noted that the exemplary method and control logic, which are described in relation to Fig. Figure 12 and each of the other different figures shown may be applicable to one or more other embodiments described herein.

[0052] The start sequence begins at step 500, in which the parking brake or park mode control 430 is engaged and all clutches (i.e., the drive clutch 420, the forward clutch 330, the reverse clutch 332, etc.) are disengaged before or during the initial start-up of the vehicle. In steps 502 and 504, the control 402 excites or pulses the drive clutch 420 and the reverse clutch 332 via the DC module 440 to engage them, so that power (e.g., rotational force or torque) from the power source is applied simultaneously or almost simultaneously to both the output shaft 302 and the countershaft 306. In step 506, the control unit 402 queries the timer module 460 to determine whether the drive clutch 420 and the reverse clutch 332 are disengaged by evaluating an input from the clock generator 410 and a stored pulse duration value or value range from the value data memory 490.In alternative embodiments, this determination can be made by using the temperature input data from temperature sensors on the drive clutch 420 and the reverse clutch 332 and the stored temperature threshold or value range, which are correlated to indicate the engagement period of the clutches, instead of using the clock input by the controller 402. In each case, depending on the determination made by the controller 402, the control logic returns to steps 502 and 504 to further excite the drive clutch 420 and the reverse clutch 332, or when the pulse duration has expired, the procedure continues with step 508, in which the controller 402 instructs the disconnect synchronizer 340 to engage via the DC module 440. In step 510, the controller 402 again instructs the forward clutch 330 to engage via the DC module.In step 512, the start sequence of the gearbox 100 or the reverse switch device 300 is completed according to one embodiment. In other embodiments, one or more of these steps or processes can be omitted, repeated, or rearranged and still achieve the desired results.

[0053] Fig. Figure 13 shows a flowchart with a control logic by which the control system 400 implements a method for switching between a forward mode and a reverse mode in the gearbox 100 or the reverse switch device 300 according to one embodiment. At step 520, the method starts, and at step 522, the controller 402, via the DC module 440, has previously instructed the forward clutch 330 to engage, so that the gearbox 100 is in forward mode F. (At step 522, the controller 402 can also engage a countershaft brake, if one is present.) At step 524, the controller 402 and the operator controller 418 receive a reverse command via the UI module 452 and instruct the gearbox 100 or the reverse switch device 300, via the DC module 440, to switch from forward mode F to reverse mode R.(The control unit 402 would disengage a countershaft brake, if present, via the DC module 440, which allows the countershaft 306 to rotate.) At step 526, the control logic proceeds to the one in . Fig. The subprogram shown in Figure 13A engages the disconnect synchronizing device 340 according to an embodiment described in detail in the following paragraphs. When the disconnect synchronizing device 340 is engaged, at step 528 the controller 402 disengages the forward clutch 330 via the DC module 440, which disconnects the output gear 312 from the output shaft 302. This allows the output gear 312 to rotate independently of the output shaft 302, and in this case, the countershaft 306 rotates in the opposite direction to the output shaft 302. At step 530, the controller 402 engages the reverse clutch 332 via the DC module 440, which detachably connects the second reverse gear 318 to the countershaft 306.This causes the countershaft 306 to rotate in the same direction as the output shaft 302, based on the engagement of the first reverse gear 310, which is mounted on the output shaft 302, with an idler gear 316, which is mounted on an idler shaft 304, and the engagement of the idler gear 316 with the second reverse gear 318. Step 532 completes the procedure for switching between a forward mode and a reverse mode in a transmission reverse switch according to one embodiment. In other embodiments, one or more of these steps or operations can be omitted, repeated, or reversed and still achieve the desired results.

[0054] Fig. Figure 13A shows a flowchart for a subprogram for engaging the disconnect synchronizer 340 according to one embodiment. The illustrated control logic generally controls the engagement of the disconnect synchronizer 340 to detachably connect the third return gear 320 to the countershaft 306 and thereby control the engagement of the third return gear 320 with the output gear 312 in a controlled manner, which can reduce imprecise gear engagement or other wear on the disconnect synchronizer 340, the return switch device 300, and the gearbox 100 as a whole.

[0055] At step 540, the subroutine, initiated by the controller 402 via the DC module 440 and the DSE module 450, instructs pressure to be applied to the isolation synchronization device 340. The instructed pressure is limited to an initial pressure value or range of pressure values ​​stored in the value data memory 490, which is lower than the maximum pressure or any other operating pressure value of the system. The controller 402 can immediately control the full initial pressure. In the illustrated example, the controller 402, as informed by the pressure module 480 and the value data memory 490, instructs the DC module 440 and the DSE module 450 to increase the pressure linearly (or possibly non-linearly) over a prescribed initial ramp-up period (which may be a value or a range of time or counter values ​​stored in the value data memory 490).At step 542, the controller 402, as informed by the timer module 460, queries the pressure module 480, which receives an input from the pressure sensor 416, and the value data storage 490, via the DSE module 450, to determine whether the initial pressure has been reached. If not, the control logic returns to step 540 and continues to increase the pressure on the separation synchronization device 340 until the initial pressure is reached.

[0056] At step 544, upon reaching the initial pressure value, the controller 402 instructs the synchronizer 340 to maintain the pressure at this initial value to confirm the synchronization of the disconnect synchronizer 340. To achieve this, at step 546, the controller 402, as informed by the speed module 470, the speed sensors 412 and 414, and the data storage unit 490, queries the DSE module 450 to determine whether an intervention slip threshold has been reached. The intervention slip threshold can be a stored value or a range of slip values ​​or other values ​​(e.g., speed values ​​or ranges) that indicate intervention by the disconnect synchronizer 340, such as speeds or one or more differential speeds above the disconnect synchronizer 340.The controller 402, as informed by the speed module 470 and the value data storage 490, can resolve the slip via the separation synchronization device 340 by evaluating speed input signals from the speed sensors 412, 414 via the DSE module 450. For example, the speed sensor 412 can detect the speed of the third return wheel 320, and the speed sensor 414 can detect the speed of the drum 342. In further embodiments, the speed sensors 412, 414 can detect other components that rotate relative to each other at a specific point during the operation of the separation synchronization device 340 (e.g., the countershaft 306 or the hub 350 and the shift sleeve 348).

[0057] If the slip corresponding to the detected speed difference across the separation synchronization device 340 is greater than the stored slip threshold, then the controller 402 maintains the pressure on the separation synchronization device 340 at the initial pressure when it attempts to confirm the completed synchronization. Specifically, in the exemplary subroutine shown in step 548, the controller 402 initiates a timer or counter for the elapsed time since the start of a synchronization attempt via the timer module 460 (and the clock generator 410), e.g., the elapsed time that begins when the separation synchronization device 340 reaches the initial pressure or when the controller 402 has determined this.At step 550, the controller 402, as informed by the timer module 460 (and the clock generator 410) and the value data storage 490, queries the DSE module 450 to determine whether a predetermined time interval intended for synchronization has elapsed. If the controller 402 determines that step 550 is true (i.e., synchronization has elapsed), the control logic proceeds to step 554, in which the controller 402, via the DC module 440, instructs the parking brake or the park mode module 430 to engage (and otherwise shifts the transmission or the vehicle into a park mode). If step 550 is false, the control logic returns to step 544, after which the controller 402 again checks the synchronization (i.e., the engagement) of the disconnect synchronizer 340.

[0058] At step 556, upon full engagement, the controller 402 instructs a final pressure for the separation synchronization device 340 via the DC module 440. The instructed pressure can be a maximum or further higher operating pressure value or range of pressure values ​​that may be stored in the value data memory 490. The controller 402 can control the full final pressure immediately. In the illustrated example, the controller 402, as informed by the pressure module 480 and the value data memory 490, instructs the DC module 440 and the DSE module 450 to increase the pressure linearly (or possibly non-linearly) over a prescribed final ramp-up time (which may be a value or a range of time or counter values ​​stored in the value data memory 490).At step 558, the controller 402, as informed by the timer module 460, queries the pressure module 480 (and the pressure sensor 416) and the value data storage unit 490 via the DSE module 450 to determine whether the final pressure has been reached. If not, the control logic returns to step 556 and continues to increase the pressure on the separation synchronization device 340 until the initial pressure is reached. Once the final pressure has been reached, the subroutine ends and the procedure described above is continued at step 528. Fig. 13 continued.

[0059] Fig. Figure 14 shows a flowchart with a control logic by which the control system 400 implements a method for switching between a reverse mode and a forward mode in the gearbox 100 or the reverse switch device 300 according to one embodiment. At step 560, the method starts, and at step 562, the controller 402 has previously instructed the reverse clutch 332 and the disconnect synchronizer 340 via the DC module 440 to engage such that the gearbox 100 is in reverse mode R. At step 564, the controller 402 receives a forward command via the UL module 452 and the operator control 418 and instructs the gearbox 100 or the reverse switch device 300 via the DC module 440 to switch from reverse mode R to forward mode F.In step 566, the controller 402, via the DC module 440, instructs the reverse clutch 332 to disengage, which disconnects the second return gear 318 from the countershaft 306 (or, in an alternative embodiment, disconnects the first return gear 310 from the output shaft 302), allowing the countershaft 306 to rotate independently of the output shaft 302. In step 568, the controller 402, via the DC module 440, instructs the forward clutch 330 to engage, which detachably connects the output gear 312 to the output shaft 302, causing the output gear 312 to rotate with the output shaft 302. This causes the countershaft 306 to rotate in the same direction as the output shaft 302 based on the engagement of the first reverse gear 310, which is mounted on the output shaft 302, with an idler gear 316, which is mounted on an idler shaft 304, and the engagement of the idler gear 316 with the second reverse gear 318.At step 570, the control logic goes to the one in . Fig. 14A and Fig. The subprogram shown in Figure 14B describes, in detail, in the following sections, the following embodiment. Step 572 completes the procedure for switching between a reverse mode and a forward mode in a gear reverse switch according to one embodiment. In other embodiments, one or more of these steps or operations can be omitted, repeated, or reversed and still achieve the desired results; for example, the controller 402 can instruct a countershaft brake (if present) to engage in order to slow down or stop the rotation of the countershaft 306 at certain times when it is in forward mode F.

[0060] Fig. Figure 14A shows a flowchart for a subroutine for deciding the engagement or disengagement of the disconnect synchronizing device 340 according to one embodiment. The illustrated control logic generally controls the engagement and disengagement of the disconnect synchronizing device 340 in order to detachably connect the third return gear 320 to the countershaft 306 and thereby control the engagement of the third return gear 320 with the output gear 312.The illustrated control logic further ensures efficient operation of the transmission or vehicle by intelligently managing the engagement state of the disconnect synchronizer 340, for example to engage the disconnect synchronizer 340 under certain operating conditions to achieve fast forward / reverse shifting with little or no delay, and to disengage the disconnect synchronizer 340 under other operating conditions to reduce wear and energy consumption associated with its engagement.

[0061] At step 540, the subroutine begins in which the controller 402, as informed by the speed module 470, queries the DSE module 450 to determine whether the gearbox 100 or the reverse switch device is operating below a prescribed first speed threshold, which can be a stored speed value or a range of values ​​stored in the value data memory 490. It should be understood that the prescribed speed threshold can correspond to one or more rotary or linear speeds assigned to the gearbox 100 or the reverse switch device 300, or to a vehicle in which they are installed.Thus, the rotational speed can be determined by the rotational speed module 470, which receives detected rotational speed signals from various rotary or linear velocity sensor devices, including the rotational speed sensors 412, 413, and 414, which can detect the speeds of various components of the transmission 100, the reverse switch device 300, or other components of a vehicle in which they are installed, as well as a vehicle's base speed device (e.g., a speedometer, etc.). In each case, the detected rotational speed and the stored rotational speed thresholds can be processed by the controller 402 or other controllers to correlate with a base speed value. The control logic can be useful, for example, in the subroutine shown, to determine the engagement state of the disconnect synchronizer 340 with respect to one or more base speed values ​​(e.g.,To manage relatively low base speed values ​​(such as <5 km / h), the following description of the exemplary control logic is understood in at least one such context. Furthermore, since the base speed can be detected or correlated using a single sensor (e.g., sensor 413 configured to detect the speed of the output gear 312), this will be discussed below and in [reference to relevant section]. Fig. Reference is made to 14A.

[0062] If the controller 402 determines that the rotational speed is below the first speed threshold, the control logic instructs the engagement of the isolation synchronizer 340. This is done at step 582 by first checking whether the isolation synchronizer 340 is currently engaged. If it is not, the controller 402, at step 584, instructs the engagement of the isolation synchronizer 340 via the DC module 440 and the DSE module. Otherwise, it returns to step 580 to check the rotational speed again. This process continues until step 580 is again incorrect, thus indicating that the procedure from Fig. 14 The vehicle is controlled in forward mode F to maintain the engagement of the disconnect synchronizer 340 at low speeds (e.g., <3 km / h). This prepares and effectively selects the reverse switch device 300 to switch to reverse mode R without requiring a period of zero power during the shift transition, since the disconnect synchronizer 340 engages while it is outside the power flow of the transmission 100 or the reverse switch device 300.

[0063] In step 586, when the first speed threshold is exceeded, the controller 402 queries the speed in relation to a stored, predefined second speed threshold via the speed module 470 and the value data memory 490. This second speed threshold is a higher speed value or range of values ​​than, or corresponds to, the first speed threshold. It should be noted that the controller 402 evaluates the second speed threshold at least partially to account for hysteresis in the detected speed signals. Therefore, the second speed threshold can be close to (e.g., 4 km / h) the value of the first speed threshold and provides an upper limit. In fact, in alternative embodiments of the control logic for applications with low or negligible hysteresis, or which do not account for hysteresis, the second speed threshold can be omitted.If the speed is below the second speed threshold, the control logic always returns to 582, where the state of the separation synchronization device 340 is queried and the speed is re-evaluated with respect to the first and second speed thresholds.

[0064] At step 588, if the rotational speed exceeds the second speed threshold, the controller 402 again queries the engagement status of the disconnect synchronizer 340. If the disconnect synchronizer is engaged, at step 590 the controller 402 initiates a timer or counter via the timer module 460 (and the clock generator 410) to record the elapsed time period above the second speed threshold. At step 592, the controller 402, as informed by the timer module 460 (and the clock generator 410) and the data storage module 490, queries the DSE module 450 to determine whether a predetermined time period (e.g., 30 seconds) allocated for synchronization, which is assigned to the engagement of the disconnect synchronizer 340 above the second speed threshold, has elapsed. If this is not the case, the controller 402 queries in a similar way to steps 580 and 586 at step 594 (i.e.By comparing the detected rotational speed with stored rotational speed thresholds, the control logic checks whether the rotational speed is above a prescribed third rotational speed threshold, which is stored in the value data memory 490 as an assigned value or range of values. The third rotational speed threshold is higher than the second threshold and can correspond to operation at a higher rotational speed (e.g., 20 km / h) of the vehicle in forward mode F. If the rotational speed is lower than the third rotational speed threshold, the control logic returns to step 590, in which the timer continues to run and the controller 402 checks the time and rotational speed thresholds again. If the controller 402 determines that step 588 does not apply or that either step 592 or 594 applies (i.e., above either the time or rotational speed thresholds), then the control logic proceeds to step 596, in which the controller 402 can instruct the disconnect synchronizer 340 to disengage via the DC module 440 and the DSE module 450.The subroutine is terminated and the process is completed. Fig. 14 is associated with the in Fig. The subprogram shown in 14B was continued.

[0065] Fig. Figure 14A shows a flowchart for a subroutine for determining the presence of engagement or disengagement of the separation synchronization device 340 according to one embodiment. At step 600, the controller 402, as informed by the speed module 470, the speed sensors 412, 414, and the value data memory 490, queries the DSE module 450 to determine whether a speed difference (or slip) exists across the separation synchronization device 340. This can be done by evaluating the detected speed signals from the speed sensors 412, 414 in relation to each other or by comparing them with a speed difference threshold or a slip threshold value or value range in the value data memory 490. As previously described, in order to determine a speed difference across the separating synchronizing device 340, the speed sensor 412 can detect the speed of the third return wheel 320 and the speed sensor 414 can detect the speed of the drum 342.In further embodiments, the speed sensors 412, 414 can detect further components that rotate relative to each other at a specific point during the operation of the separation synchronizing device 340 (e.g. the countershaft 306 or the hub 350 and the shift sleeve 348).

[0066] If no speed difference is determined at step 600, the control unit 402 temporarily energizes and pulses the reverse clutch 332 via the DC module 440 and the DSE module 450. This temporarily applies energy to the disengaging synchronizer 340 via the countershaft 306 (temporarily a four-squared of the transmission) to very briefly apply torque in order to disengage certain components (e.g., shift sleeve and gear cone) that were inadvertently held in engagement. At step 604, the control unit 402 again checks the speed difference across the disengaging synchronizer 340 in the same way as at step 600. If a speed difference exists due to the pulsing at step 602 or for other reasons, and the disengagement is confirmed, then the subroutine terminates and returns to step 572 in the procedure described above. Fig. 14, in which the procedure for switching between a reverse mode and a forward mode in a transmission reverse switch, according to one embodiment, is completed. If this is not the case, the control unit, via the DC module 440, instructs the engagement of the parking brake or mode 430.

[0067] It is understood that when the disengaging synchronizer 340 is disengaged, the countershaft 306 and, consequently, the reverse clutch 332 are disconnected from the output gear 312. In this state, the differential speed across the disengaged reverse clutch 332, which would have existed without this disengagement, along with the associated wear caused by the various effects of air movement, gyroscopic flutter, and other air resistances between the relative rotating elements of the disengaged reverse clutch 332, is eliminated. Avoiding such effects, which can be particularly damaging when the transmission is operated beyond certain maximum design parameters (e.g., when the vehicle is driven at excessive speeds by gravity), improves the service life of the reverse clutch 332 and thus, overall, the transmission 100 and the reverse switch device 300.

[0068] The control logic of the subprograms shown was compared to the procedures of Fig. 13 and Fig. 14 described, where the subroutine of Fig. 13A is described in relation to a reverse mode R and the subroutine of the Fig. 14A and Fig. 14B are described in relation to a forward mode F. It is understood that the subprograms can be implemented in gearboxes or reverse switch devices that operate in different modes or according to other procedures or control logics.

[0069] Without limiting the scope of protection, interpretation, or application of the claims set forth below, one technical effect of one or more of the embodiments disclosed herein is a double-disconnect transmission reverse switch for changing the direction of a vehicle between forward and reverse. Another technical effect of one or more of the embodiments disclosed herein is a transmission reverse switch that reduces air movement or friction in a disengaged reverse clutch. A further technical effect of one or more of the embodiments disclosed herein is a transmission reverse switch that reduces the likelihood of gyroscopic flutter in the disengaged reverse clutch due to lower rotational speeds.Another technical effect of one or more of the embodiments disclosed herein is a transmission reverse switch that can hinder or stop a counter-rotation of the reverse clutch during high forward speeds of the vehicle.

[0070] The terminology used herein serves the purpose of describing certain embodiments or applications and is not intended to limit the disclosure. As used herein, the singular forms "a" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It is further understood that the use of the expressions "have," "include," "comprise," or the like in this description indicates the presence of specified features, integers, steps, processes, elements, and / or other components, but does not preclude the presence or addition of one or more further features, integers, steps, processes, elements, components, and / or groups thereof.

[0071] The reference numerals “A” and “B”, used herein together with reference numbers, serve only to clarify when describing multiple applications of a device.

[0072] One or more of the steps or operations in any of the procedures, processes or systems discussed herein may be omitted, repeated or rearranged and are within the scope of protection of this disclosure.

[0073] While the method described above represents embodiments of the present disclosure, these descriptions should not be considered in a limiting or restrictive sense. Rather, there are several variations and modifications that can be made without deviating from the scope of protection of the appended claims.

Claims

[1] Gear reverse switch (110; 300) for reversing the direction of an output gear (122; 312) carried by an output shaft (112; 302), comprising the gear reverse switch (110; 300): a return shaft (116; 306); a reverse clutch (132; 332) which is mounted around the return shaft (116; 306) and has engaged and disengaged states; and a reverse separation synchronizing device (340) which is mounted around the reverse shaft (116; 306) and has engaged and disengaged states; wherein, when the reverse clutch (132; 332) and the reverse disconnect synchronizer (340) are in the engaged states, the reverse shaft (116; 306) rotates the output gear (122; 312) in a reverse direction of rotation opposite to the direction of rotation of the output shaft (112; 302); and wherein, when the reverse separating synchronizing device (340) is in the disengaged state, the reverse clutch (132; 332) is separated from the output gear (122; 312), characterized by , that the reverse-separation synchronizing device (340) has an actuating piston (346) which moves a switching sleeve (348) in at least one axial direction of the transmission reverse switch (110; 300); wherein the actuating piston (346) has a first annular surface (390) with a first locking feature (388); wherein the switching sleeve (348) has a second annular surface (391) with a second locking feature (389) configured to engage with the first locking feature (388) of the actuating piston (346), wherein the switching sleeve (348) is connected to the actuating piston (346) by overlapping radial surfaces (392, 393) of the first and second locking features (388, 389) when the first and second annular surfaces (390, 391) are arranged concentrically. [2] Gearbox reverse switch according to claim 1, further comprising: a first return wheel (120; 310) which is mounted on the output shaft (112; 302); an idle shaft (114; 304), including an idle wheel (124; 316) engaged with the first reverse wheel (120; 310); a second return wheel (126; 318) which is engaged with the idle wheel (124; 316); and a third return wheel (128; 320) which is mounted around the return shaft (116; 306) and is engaged with the output wheel (122; 312), wherein the third return wheel (128; 320) is connected to the return shaft (116; 306) when the return separating synchronizing device (340) is in the engaged state; characterized by , that when the reverse clutch (132; 332) and the reverse separating synchronizing device (340) are in the engaged states, the reverse shaft (116; 306) rotates relative to the output shaft (112; 302) based on the ratios of the first reverse gear (120; 310) to the idler gear (124; 316) and the idler gear (124; 316) to the second reverse gear (126; 318), and the output gear (122; 312) rotates relative to the reverse shaft (116; 306) based on a ratio of the third reverse gear (128; 320) to the output gear (122; 312). [3] Gearbox reverse switch according to claim 2, characterized by, that the reverse clutch (332) in the engaged state connects the second reverse wheel (318) detachably to the reverse shaft (306) and the reverse clutch (332), in the engaged state of the reverse separating synchronizing device (340), detachably connects the third reverse wheel (320) to the reverse shaft (306). [4] Gearbox reverse switch according to claim 1, further comprising: a forward clutch (130; 332) which is mounted around the output shaft (112; 302) and has engaged and disengaged states, wherein the forward clutch (130; 332) detachably connects the output gear (122; 312) to the output shaft (112; 302) in the engaged state; characterized by , that in a forward mode in which the reverse clutch (132; 332) is in the disengaged state and the forward clutch (130; 332) is in the engaged state, the output gear (122; 312) rotates in the direction of rotation of the output shaft (112; 302). [5] Gearbox reverse switch according to claim 4, characterized by , that the forward mode continues to include the reverse clutch (132; 332) in the disengaged state and the reverse separating synchronizing device (340) in the engaged state below at least one speed threshold and one time threshold, and in the disengaged state above at least one speed threshold and one time threshold. [6] Gearbox reverse switch according to any one of claims 1 to 5, characterized by , that the return separation synchronizing device (340) is a fork-free hydraulic synchronizing device. [7] Gearbox reverse switch according to claim 6, characterized by , that the reverse separation synchronizing device (340) has a hub (350) which is mounted around the reverse shaft (116; 306) and defines a piston chamber (344) in which fluid pressure drives an actuating piston (346) to move a shift sleeve (348). [8] Gearbox reverse switch according to claim 6, further comprising: a shift sleeve (348) and a spring (380); characterized by , that the actuating piston (346) moves the shift sleeve (348) in one direction along a rotational axis of the return shaft (116; 306); and characterized by , that the spring (380) biases the actuating piston (346) to move the shift sleeve (348) in a direction opposite to the direction in which the hydraulic fluid drives the actuating piston (346). [9] Gearbox reverse switch according to claim 7, characterized by , that the reverse separation synchronizing device (340) is a semi-synchronizing device comprising a single actuating piston (346) and a single switching sleeve (348) which is moved by the actuating piston (346) in at least one direction along the axis of rotation of the reverse shaft (116; 306). [10] Gearbox reverse switch according to one of the preceding claims, characterized by , that the coupling of the first and second locking features (388, 389) connects the shift sleeve (348) and the actuating piston (346) with relative freedom of rotation. [11] Gearbox reverse switch according to one of the preceding claims, characterized by , that in at least one state of the transmission reverse switch (110; 300) the radial surfaces (392, 393) of the first and second locking features (388, 389) interlock to prevent the separation of the switching sleeve (348) from the actuating piston (346) in at least one axial direction. [12] Gearbox reverse switch according to one of the preceding claims, characterized by , that the radial surfaces (392, 393) are oriented essentially perpendicular to the return shaft (116; 306). [13] Gearbox reverse switch according to one of the preceding claims, characterized by, that the first and second annular surfaces (390, 391) each comprise first and second undercut recesses adjacent to the radial surfaces (392, 393) of the first and second locking features (388, 389); and characterized by , that the first and second ring surfaces (390, 391) each comprise first and second chamfered front edges (396, 397) which face the other first and second ring surface (390, 391). [14] Gearbox reverse switch according to one of the preceding claims, characterized by , that the actuating piston (346) is made of a first material and the switching sleeve (348) is made of a second material that differs from the first material. [15] Gearbox reverse switch according to one of the preceding claims, characterized by , that the first and second locking features (388, 389) are coupled by a press fit of the ring piston (346) onto the switching sleeve (348). [16] Gearbox reverse switch according to one of the preceding claims, characterized by that the ring piston (346) comprises one or more peripheral notches (398) on a leading edge (396) of the first ring surface (390).

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