AXIAL SWITCHING ARRANGEMENT FOR A TRANSMISSION

Abstract

Axial shifting arrangement for a transmission. The axial shifting arrangement comprises a gear and a shift sleeve arranged coaxially to each other. The shift sleeve has at least one axial tooth projecting axially and movable axially between an engaged position, in which the at least one axial tooth is in drive engagement with the gear, and a disengaged position, in which the at least one axial tooth is disengaged from the gear. The axial shifting arrangement also includes a piston, which is arranged at least partially radially inward from the shift sleeve. The shift sleeve moves with the piston. The piston can be actuated between a first axial position, corresponding to the disengaged position, and a second axial position, corresponding to the engaged position.

Description

TECHNICAL AREA

[0001] The present disclosure relates generally to an axial switching arrangement for a transmission, such as a work vehicle transmission. BACKGROUND

[0002] A shift mechanism can be used to selectively engage or disengage a gear in a transmission. Shift mechanisms are typically bulky and expensive. SUMMARY

[0003] The disclosure provides a compact switching arrangement with a switching device in the shaft. The disclosure also provides a device for overcoming the restoring force of a preload element in the switching arrangement to improve its disassembly and ease of maintenance.

[0004] According to one aspect, the disclosure provides an axial shifting arrangement for a transmission. The axial shifting arrangement comprises a gear and a shift sleeve, which are arranged coaxially to each other. The shift sleeve has at least one axial tooth that projects axially and is axially movable between an engaged position, in which the at least one axial tooth is in drive engagement with the gear, and a disengaged position, in which the at least one axial tooth is disengaged from the gear. The axial shifting arrangement also includes a piston that is arranged at least partially radially inward from the shift sleeve. The shift sleeve moves with the piston. The piston is actuated between a first axial position, corresponding to the disengaged position, and a second axial position, corresponding to the engaged position.

[0005] In another aspect, the disclosure provides a vehicle that includes a gear transmission with an axial shift arrangement.

[0006] According to yet another aspect, the disclosure provides an axial switching arrangement. The axial switching arrangement comprises a central shaft and a switching sleeve that is axially movable relative to the central shaft into and out of engagement with a coaxial gear. The switching arrangement also includes a piston that is arranged at least partially radially inward from the switching sleeve. The switching sleeve moves axially with the piston. The piston can be actuated between a first axial position and a second axial position. The axial switching arrangement also includes a preload element that is arranged at least partially radially inward from the switching sleeve and preloads the piston into the first axial position or the second axial position, and a holding device for holding the preload element relative to the central shaft. The holding device is detachably fastened relative to the central shaft.

[0007] In yet another aspect, the disclosure provides a method for using an axial switching arrangement with a switching sleeve and a coaxial gear arranged around a central shaft. The method comprises axially moving the switching sleeve into and out of drive engagement with the coaxial gear via a piston that is arranged at least partially radially inward from the switching sleeve, pre-tensioning the piston using a pre-tensioning element, and holding the pre-tensioning element using a holding device that is detachably connected to the central shaft.

[0008] Further features and aspects will become apparent upon consideration of the detailed description, the claims and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The detailed description of the drawings refers to the enclosed figures. Fig. Figure 1 is an expanded cross-sectional view of an axial switching arrangement according to an implementation of the present disclosure. Fig. Figure 2 is a perspective view of the axial switching arrangement of Fig. 1. Fig. Figure 3 is a cross-sectional side view of the axial switching arrangement of Fig. 1, wherein a shift sleeve is in a disengaged position. Fig. Figure 4 is a cross-sectional side view of the axial switching arrangement of Fig. 1, wherein the switching sleeve is in a recessed position. Fig. Figure 5 is an enlarged view of a section of the axial switching arrangement of Fig. 3. Fig. 6 is a first alternative to the one in Fig. Section 5 of the axial switching arrangement shown. Fig. 7 is a second alternative to the one in Fig. Section 5 of the axial switching arrangement shown. Fig. Figure 8 is a schematic representation of a work vehicle that has a gear transmission with the axial shift arrangement of Fig. 1 includes.

[0010] Matching reference symbols are used across different figures to indicate matching elements. DETAILED DESCRIPTION

[0011] With reference to Fig. Figures 1-4 show an axial shift arrangement 10 for a transmission. The axial shift arrangement 10 comprises a gear 12 and a shift sleeve 14, which are arranged coaxially with respect to each other around a central axis A. The shift sleeve 14 can include at least one axial tooth 16 projecting axially from it. The gear 12 can include at least one corresponding axial tooth 18 for meshing with the at least one axial tooth 16 of the shift sleeve 14 in a drive engagement. Thus, the gear 12 meshes axially with the shift sleeve 14. In other implementations, other types of meshing arrangements can be used. The gear 12 further comprises radial teeth 50. The radial teeth 50 can be intended for meshing with another gear in the transmission (see Figure 1-4). Fig. 8 as an example).

[0012] The switching sleeve 14 can be axially moved between a retracted position ( Fig. 4) and a deployed position ( Fig. 3) be movable. In the engaged position, the shift sleeve 14 is engaged with the gear 12 to drive the gear 12. In the disengaged position, the shift sleeve 14 is disengaged from the gear 12, so that it does not drive the gear 12. A piston 20 is arranged at least partially radially inwards from the shift sleeve 14. Thus, at least part of the piston 20 is enclosed in a cylindrical casing 22 ( Fig. 2) the switching sleeve 14. A radially outermost point B of the cylindrical outer surface of the switching sleeve 14 can define the cylindrical enclosure 22 around and along the central axis A. In some examples, such as the illustrated example, the piston 20 can be arranged on the central axis A, e.g., such that the central axis A intersects the piston 20. The piston 20 can be centered on the central axis A. The piston 20 can be arranged at least partially within a central shaft 26. The piston 20 can be arranged completely within the central shaft 26.

[0013] The shift sleeve 14 moves with the piston 20. The piston 20 and the shift sleeve 14 can be axially movable as a unit relative to and away from the gear 12. The piston 20 and the shift sleeve 14 can be coupled for movement in any suitable manner. For example, a fastener 46 can couple the shift sleeve 14 to the piston 20 for movement as a unit. The fastener 46 can be a bolt (and nut 48 as shown), a pin, a screw, a clamp, or any other suitable type of fastener.

[0014] The piston 20 is between a first axial position ( Fig. 3), which corresponds to the extended position, and a second axial position, which corresponds to the inset position, ( Fig. 4) actuated. The piston 20 can be actuated by any suitable actuator 24. For example, the piston 20 can be actuated by any of the following or any combination thereof: a pressurized fluid, an electrically controlled actuator, or manual actuation. Any type of pressurized fluid can be used. For example, the pressurized fluid can be a hydraulic fluid, a pneumatic fluid, etc. Other types of actuators are conceivable. Other combinations of actuators are conceivable. For example, the actuator 24 can be electronically controlled to control the flow of the pressurized fluid to move the piston 20. The actuator 24 can provide an external force that acts to move the piston 20 in any suitable manner. In the example shown, the external force acts coaxially with the axial switching arrangement 10.The external force can act parallel to or on the central axis A.

[0015] How best to Fig. As shown in Figures 1 and 3-4, a piston retaining device 64 and a retaining ring 66 can hold the piston 20 relative to the central shaft 26. The piston retaining device 64 can have a recess 68 through it, which allows the external force for moving the piston 20 to be transmitted through the piston retaining device 64 to the piston 20. For example, the pressurized fluid can flow through the recess 68 and into the piston retaining device 64.

[0016] The axial switching arrangement 10 can include the central shaft 26 in drive engagement with the switching sleeve 14 for rotating the switching sleeve 14 about the central axis A. The drive engagement can be a constant meshing drive engagement. The switching sleeve 14 can be disengaged from the central shaft 26 at any axial position along the central shaft 26 from the engaged position ( Fig. 4) into the deployed position ( Fig. 3) be rotary-driven. The gear 12 can be arranged on the central shaft 26 and configured to allow the central shaft 26 to rotate in the gear 12 when the shift sleeve 14 is disengaged from the gear 12 ( Fig. 3) The gear 12 can be driven to rotate by the shift sleeve 14 when the shift sleeve 14 is engaged with the gear 12 ( Fig. 4) As an example, which is best illustrated in Fig. 1 and Fig. As shown in Figure 3, the gear 12 can be attached to the central shaft 26 via a ring 62 provided with a splined toothing, so that the gear 12 can rotate with respect to the ring 62 provided with a splined toothing.

[0017] The axial switching arrangement 10 can include a preloading element 28 for preloading the switching sleeve 14 into the disengaged position ( Fig. 3) include. The preload member 28 can have any suitable preload structure that exhibits a restoring force when deformed, such as a spring, an elastic material, etc. The restoring force of the preload member 28 acts to return the piston 20 from the second axial position ( Fig. 4) into the first axial position ( Fig. 3) to press. In further implementations, the preload element 28 can act to press the piston 20 into any desired position, such as the second axial position. The preload element 28 can be arranged at least partially radially inward from the switching sleeve 14. As an example, the preload element 28 can be arranged in a cavity 30 in the central shaft 26. The preload element 28 can be arranged completely in the central shaft 26. The piston 20 can be arranged at least partially in the cavity 30 of the central shaft 26. The piston 20 can be arranged completely in the central shaft 26. The piston 20 can be arranged to be displaceable, at least partially or completely, in the cavity 30 of the central shaft 26.

[0018] The axial switching arrangement 10 can include a holding device 32 for holding the preload member 28 in the central shaft 26. The holding device 32 can be detachably fastened to the central shaft 26. One end of the preload member 28 can bear against the central shaft 26, and another end of the preload member 28 can bear against the holding device 32. Such a bearing arrangement can be direct or indirect. The restoring force of the preload member can act on the central shaft 26 at one end and on the holding device 32 at the other end. A fastening element 34 (which can also be referred to here as a holding device fastening element 34) can be used to hold the holding device 32. The fastening element 34 can be designed separately from the holding device 32 or as a solid body together with it. In the Fig. In the example shown in Figure 5, the fastening element 34 is separate from the holding device 32. The fastening element 34 can define a threaded shaft 36. The holding device 32 can be detachably fastened to the central shaft 26 via the threaded shaft 36. The threaded shaft 36 can be formed separately from the holding device 32 or as a solid body with it. The threaded shaft 36 can be screwed directly or indirectly into the central shaft 26. The threaded shaft 36 can be unscrewed from the central shaft 26 in a controlled manner for disassembly of the preload element 28, with the restoring force of the preload element 28 being released slowly. Since the holding device 32 holds the preload element 28 instead of the piston 20, removing the piston 20 during disassembly does not result in a sudden release of the restoring force of the preload element 28.The restoring force of the preload element 28 can be gradually released by unscrewing the threaded shaft 36. When the threaded shaft 36 is completely disengaged from the central shaft 26, the restoring force of the preload element 28 is relatively low or zero. This design facilitates disassembly and ease of maintenance.

[0019] With reference to Fig. 5 The fastening element 34 can be a bolt having a threaded shank 36 and a bolt head 38 that holds the retaining device 32. With reference to Fig. 6. The fastening element 34 can be a pin having a threaded shank 36 and a mechanical step 40 that engages with the central shaft 26. As in Fig. As shown in Figure 6, the fastening element 34 can have a retaining ring 42 for holding the holding device 32. Any other type of flange can be used with the fastening element 34 to hold the holding device 32. With reference to Fig. 7. A cylinder with an external and an internal thread and flange 44 can be screwed into the central shaft 26, and the fastening element 34 can be screwed into the cylinder with an external and an internal thread and flange 44. Thus, the fastening element 34 can be screwed directly or indirectly into the central shaft 26.

[0020] The axial switching arrangement 10 can be used to selectively drive or disdrive the gear 12 for any suitable application. For example, the axial switching arrangement 10 can switch between different gears. By placing the switching device (e.g., the piston 20) radially inward from the shift sleeve 14 or within the central shaft 26, the axial switching arrangement 10 is compact, lightweight, and cost-effective.

[0021] Fig. Figure 8 presents an example of an application of the axial switching arrangement 10. A vehicle 52 comprising a gear transmission 54 with the axial switching arrangement 10 is shown. The vehicle 52 can be any suitable type of vehicle with a drive source 56 and a transmission 58. The gear transmission 54 can be part of the transmission 58. As an example, the vehicle 52 can be a work vehicle capable of operating attachable and detachable implements. The work vehicle can be a tractor.

[0022] According to the representation in Fig.8. The gear unit 54 can include a power take-off (PTO) shaft 60. The gear unit 54 can include the central shaft 26 arranged as a countershaft parallel to the PTO shaft 60. (Thus, the term "countershaft" can be used synonymously with the term "central shaft 26".) The gear unit 54 can include one axial shift arrangement 10 parallel to the PTO shaft 60, two axial shift arrangements 10 (as shown) parallel to the PTO shaft 60, or more. Each axial shift arrangement 10 can be operated to selectively drive or disdrive the gear 12, which in turn can selectively drive or disdrive the PTO shaft 60, e.g., via the radial teeth 50 or any other suitable provision. For example, the axial switching arrangement 10 (or the multiple axial switching arrangements 10) can be used to select between different PTO speeds.

[0023] In operation, the axial switching arrangement 10 is engaged and disengaged by axially moving the switching sleeve 14 along the central shaft 26, engaging and disengaging the drive with the gear 12 via the piston 20, which is at least partially located in the central shaft 26. The movement of the piston 20 can be controlled electronically or manually. The external force for moving the piston 20 can be provided hydraulically, pneumatically, by a linear actuator, another mechanical actuator, manually, etc. In some examples, the piston 20 can be actuated using pressurized fluid. The piston 20 can be pre-tensioned using the pre-tensioning element 28. The pre-tensioning element 28 can be held in place by the holding device 32, which is detachably connected to the central shaft 26. The holding device 32 can be detachably connected to the central shaft 26 via the threaded shaft 36.The threaded shaft 36 can be formed separately from the holding device 32 or as a single solid component with it. An operator can unscrew the threaded shaft 36 from the central shaft 26 to reduce the restoring force of the preload element 28 when the preload element 28 is removed. The drive engagement between the switching sleeve 14 and the gear 12 is provided by at least one axial tooth 16. Other possibilities for the use of the axial switching arrangement 10 are described in detail below.

[0024] As used here, "e.g." is used to provide non-exhaustive examples and has the same meaning as alternative illustrative phrases such as "including," "including but not limited to," and "including without limitation." Enumerations with items separated by conjunctions (e.g., "and") and further preceded by the phrase "one or more of" or "at least one of" indicate, unless otherwise restricted or modified, configurations or arrangements that may include individual items in the enumeration in any set or any combination thereof.

[0025] Terms relating to a degree, such as "general", "essentially" or "approximately", refer, according to the understanding of the person skilled in the art, to reasonable ranges outside of a specified value or orientation, e.g. general tolerances or positional relationships associated with the manufacture, assembly and use of the described embodiments.

[0026] Although the foregoing describes exemplary embodiments of the present disclosure, these descriptions are not to be construed as limitations. Rather, other variations and modifications may be made without deviating from the scope of protection and nature of the present disclosure, as defined in the pending claims.

Claims

[1] Axial shift arrangement for a gearbox comprising the following: a gear and a shift sleeve arranged coaxially to each other, the shift sleeve having at least one axial tooth projecting axially from it, the shift sleeve being axially movable between an engaged position in which the at least one axial tooth is in drive engagement with the gear and a disengaged position in which the at least one axial tooth is out of engagement with the gear; and a piston which is arranged at least partially radially inwards from the shift sleeve, wherein the shift sleeve moves with the piston, wherein the piston can be actuated between a first axial position corresponding to the disengaged position and a second axial position corresponding to the engaged position. [2] Axial switching arrangement according to claim 1, which further comprises a central shaft in drive engagement with the switching sleeve for rotating the switching sleeve about a central axis of the switching sleeve and optionally wherein the piston is slidably arranged in a cavity in the central shaft. [3] Axial switching arrangement according to claim 2, which further comprises a preloading element arranged in the cavity in the central shaft to preload the switching sleeve into the disengaged position. [4] An axial switching arrangement according to claim 3, further comprising a holding device for holding the preload member in the central shaft and a fastening means that holds the holding device, wherein the fastening means is formed separately from the holding device or as a solid body with it, wherein the fastening means is screwed into the central shaft and can be unscrewed from the central shaft for disassembly of the preload member. [5] Axial switching arrangement according to any of the preceding claims, wherein the piston can be actuated by any of the following or any combination of the following: a pressurized fluid, an electrically controlled actuator or manual actuation. [6] An axial switching arrangement according to one of the preceding claims, wherein the gear further comprises radial teeth which mesh axially with the switching sleeve, and / or wherein the gear and the switching sleeve are coaxial about a central axis and the piston is arranged on the central axis, and / or wherein the axial switching arrangement further comprises a fastening means which couples the switching sleeve to the piston. [7] Vehicle comprising a gear transmission with the axial switching arrangement according to one of the preceding claims. [8] Vehicle according to claim 7, wherein the gear transmission further comprises a PTO shaft and a countershaft parallel to the PTO shaft, wherein the countershaft drives the shift sleeve and wherein the piston is slidably received in a cavity in the countershaft. [9] Axial switching arrangement comprising the following: a central wave; a shift sleeve which is axially movable with respect to the central shaft into and out of the drive engagement with a coaxial gear; a piston which is arranged at least partially radially inwards from the switching sleeve, wherein the switching sleeve moves axially with the piston, wherein the piston can be actuated between a first axial position and a second axial position; a preload element that is arranged at least partially radially inwards from the shift sleeve and preloads the piston into the first axial position or the second axial position; and a holding device for holding the preload member with respect to the central shaft, wherein the holding device is detachably fastened with respect to the central shaft. [10] Axial switching arrangement according to claim 9, wherein the holding device is detachably fastened with respect to the central shaft via a threaded shaft, wherein the threaded shaft is formed separately from the holding device or as a solid body with it, wherein the threaded shaft is unscrewable with respect to the central shaft to reduce a restoring force of the preloading element during disassembly of the preloading element. [11] Axial switching arrangement according to claim 9 or 10, wherein the piston can be actuated by a pressurized fluid and / or wherein the switching sleeve has at least one axially projecting axial tooth for axial meshing in the drive engagement with the coaxial gear. [12] Method for using an axial switching arrangement with a switching sleeve and a coaxial gear arranged around a central shaft, comprising the following: axial movement of the shift sleeve into and out of drive engagement with the coaxial gear via a piston which is arranged at least partially radially inwards from the shift sleeve; Pre-tensioning the piston using a pre-tensioning element; and Holding the preload member using a holding device that is detachably connected to the central shaft. [13] The method of claim 12, further comprising: Detachable connection of the holding device to the central shaft via a threaded shaft, wherein the threaded shaft is formed separately from the holding device or as a solid body with it; and Unscrewing the threaded shaft relative to the central shaft to reduce the restoring force of the preload member during disassembly of the preload member. [14] Method according to claim 12 or 13, wherein the drive engagement between the shift sleeve and the coaxial gear is provided by at least one axial tooth. [15] Method according to any one of claims 12 to 14, further comprising actuating the piston using a pressurized fluid.

Images