Connecting and disconnecting device for a vehicle powertrain

Abstract

Vehicle drivetrain designed to propel a vehicle (100) with a traction element (130, 132) engaging with a surface, the drivetrain comprising: a gearbox (122) with a gearbox coupling element (140); a final drive arrangement (104, 118) configured to drive the traction element (130, 132) engaging with a surface, wherein the final drive arrangement (104, 118) has a drive element (150) spaced apart from the transmission coupling element (140) to create a gap between to define the drive element (150) and the transmission coupling element (140); and a coupling device (152) which is at least partially arranged in and coupled to the drive element (150), wherein the coupling device (152) in a first position (162) does not extend over the gap, so that the drive element (150) and the gear coupling element (140) are not connected by the coupling device (152), and in a second position (164) extends from the drive element (150) to the gear coupling element (140) over a distance sufficient to extend over the gap in order to connect the drive element (150) to the gear coupling element (140) in a ready-to-use manner, wherein the coupling device (152) comprises a coupling shaft (160) with dimensions sufficient to extend over the gap, and a drive actuation device (184) which is coupled to the coupling shaft (160) in a ready-to-operate manner, wherein the drive actuation device (184) is designed to move the coupling shaft (160) along a longitudinal axis (148) of the coupling device (152) over a distance sufficient to extend over the gap and to engage the transmission coupling element (140) with the drive element (150), wherein the coupling shaft (160) has external teeth (168) which are designed to engage with internal teeth (204) of the transmission coupling element (140) in the second position (164), and wherein the coupling shaft (160) is designed to move, when the coupling shaft (160) moves from the first position (164) to the second position (164) along the longitudinal axis (148) into a cavity (180) defined by the transmission coupling element (140), wherein the drive actuation device (184) further comprises a linear actuating part (196) which is coupled in an operational state to the coupling shaft (160) and to the drive element (150), wherein the linear actuating part (196) is configured to move the coupling shaft (160) along the longitudinal axis (148); and remains at a fixed position along the longitudinal axis (148) during a movement of the linear actuating part (196), wherein the drive actuation device (184) has a user-accessible drive which is operationally connected to the linear actuating part (196), wherein the user-accessible drive has a first position (201) which prevents the drive from moving the coupling shaft (160) along the longitudinal axis (148), and a second position (203) which allows, that the linear actuating part (196) moves the coupling shaft (160) along the longitudinal axis (148), and wherein the user-accessible drive has a preloading element (198) which is located between a section of the user-accessible drive and the linear actuating element (196), wherein the preloading element (198) has a first state to preload the user-accessible drive into the first position (201) and a second state to preload the user-accessible drive into the second position (203).

Description

AREA OF INVENTION

[0001] The present invention relates to a power transmission arrangement for a motor-driven vehicle and in particular to a transmission and a final drive arrangement of a drive train of the motor-driven vehicle. BACKGROUND

[0002] Vehicles can have a primary drive, such as an engine, to generate power and a transmission assembly coupled to the primary drive to transfer the power to a power transmission or final drive assembly. The final drive assembly moves a gear or drive hub that propels the vehicle along a surface. Such vehicles, in various configurations, have one or more traction elements, such as wheels or tracks, that engage with a surface and are driven by the final drive assembly. In many configurations, the output of the transmission, typically a driveshaft, is connected to an input of the final drive assembly.

[0003] During vehicle operation, it may at some point be desirable or necessary to service or maintain the transmission. This may involve removing the transmission from the vehicle. In other situations, it may be necessary to remove the drive assembly from the vehicle. Still other situations may require towing the vehicle from one location to another for repair or maintenance. In each of these situations, the transmission output is often disconnected from the drive assembly to perform maintenance. Alternatively, the final drive assembly can be completely removed from the vehicle, although this removal can be extremely complex and time-consuming.

[0004] On some tracked vehicles, such as military vehicles, an access opening, such as a hatch, may be provided for a technician to access the gearbox output, allowing the gearbox output to be completely disconnected from the final drive assembly within the enclosed space. While access to the opening does not require any special tools, the amount of space available to disconnect and reconnect the gearbox to the drive assembly is limited. In other cases, the design of the final drive assembly and the sprocket for the track is such that there is either limited or no access through the final drive assembly to reach the gearbox. A hatch would be required for access within the vehicle's interior. In other situations, it may be necessary to disconnect the final drive assembly from the drivetrain and remove it from the vehicle before the gearbox can be serviced.Maintenance in these cases can require a significant amount of time and effort.

[0005] Therefore, means are needed to connect and / or disconnect a final drive assembly from a transmission output, thereby reducing the amount of time and labor required during servicing, repair, or towing of a vehicle. Furthermore, it would be desirable to provide a connection and disconnection mechanism that offers improved access to the drive components.

[0006] US Patent 5,26,915 A discloses a planetary drive assembly for a vehicle, which includes a wheel mounting spindle. A linkage mechanism comprises a coupling shaft having a reduced neck section that slides in an axial bore and is fitted with an O-ring seal to prevent lubricant leakage. The coupling shaft also includes an enlarged head section with a circumferential rib that fits into a countersunk bore of a spindle. The coupling shaft is axially displaceable.

[0007] Publication US,3,504,564 A describes a final drive unit comprising a planetary reduction gear and an externally accessible disconnect device for use on a vehicle to disconnect the drives between the transmission output and the final drive input, thereby preparing the vehicle on site for towing operations. SUMMARY

[0008] According to one embodiment of the invention, means are provided to either connect shafts for transmitting mechanical power to one another or to disconnect these shafts from one another, thereby preventing the flow of mechanical power from one element to another. The connection and disconnection functions are accomplished without removing the power transmission elements (engine, transmission, final drive) from the vehicle, and such functions can be rapidly reversed to return to an original state. The features of a connection and disconnection device provide axial movement of coupling components and actively position the coupling components either in the connected state or in the disconnected state.

[0009] In particular, the invention proposes a vehicle powertrain with the features of independent claim 1, a connection and disconnection arrangement for a vehicle powertrain with the features of independent claim 10, and a method for disconnecting and connecting a transmission with the features of independent claim 14. The dependent claims define preferred and / or advantageous embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The aspects of the present invention described above and the manner in which they are achieved will become more apparent by reference to the following description of the embodiments according to the invention together with the accompanying figures, and the invention itself will be better understood. Fig. Figure 1 is a partially perspective view of the front section of a vehicle with a final drive arrangement held by a body of the vehicle. Fig. Figure 2 is a schematic representation of the front section of a tracked vehicle with a gearbox, a final drive arrangement and vehicle tracks. Fig. Figure 3 is a schematic cross-sectional view of a gear drive element, a drive gear of a final drive arrangement and a coupling device, shown in a first and a second position. Fig. Figure 4 is a schematic cross-sectional view of a gear drive element, a drive gear of a final drive arrangement and a coupling device, shown in a first and a second position.

[0011] Appropriate reference symbols are used to designate corresponding parts throughout the various representations. DETAILED DESCRIPTION

[0012] The embodiments of the invention described below are not intended to be exhaustive, nor are they intended to limit the invention to the precise embodiments disclosed in the detailed description below. Instead, the embodiments have been chosen and described in such a way that the person skilled in the art will understand the principles and workings of the present invention.

[0013] In a general sense, the present disclosure relates to the control of a torque transmission from one part to another. In one state, a first part and a second part can be coupled or connected to each other so that a torque can be transmitted between them, and in a second state, the first and second parts can be decoupled or separated from each other so that no torque can be transmitted between them. While this disclosure provides various examples of this control in a vehicle application, the disclosure is not intended to be limited to this application. The person skilled in the art will recognize that various aspects of the present disclosure are provided therein outside of the vehicle application.

[0014] Fig. Figure 1 represents an embodiment of a front section of a machine or vehicle 100. In the illustrated embodiment, a front section of a tracked vehicle without the tracks is shown. The vehicle has a body or hull 102, which is configured to hold the various arrangements and components of the vehicle, including a final drive assembly 104. The final drive assembly 104 is located in a cavity 106, which is situated in a side 108 of the body 102. The final drive assembly 104 is held in the cavity 106 by several fastening means 110. The final drive assembly 104 has a drive hub 112, which is configured to hold and drive the track (not shown) of the vehicle.The drive assembly also features an access point 114, which defines an opening through which a connection and disconnect mechanism within the final drive assembly 104 is operated. A cap 116 is designed to be inserted into the access point 114 to cover the opening and essentially prevent the unwanted ingress of dirt or foreign matter into the final drive assembly. The final drive assembly 104 shown is located on the right side of the vehicle. A second final drive assembly 118 (not shown) is located on the left side of the vehicle.

[0015] Fig. Figure 2 is a schematic representation of a front section 120 of the vehicle 100 with a transmission 122. A transmission output shaft (not shown) is operationally connected to the transmission 122 and the final drive assembly 104. The final drive assembly 104 is connected by the drive hub 112 of the Fig. 1. The final drive assembly 118 is connected to a first chain 130 or a traction element engaged with a surface. The final drive assembly 118 is coupled to another side of the gearbox 122, which is connected to a second chain 132 in a ready-to-operate manner. During operation of the vehicle 100, a primary drive 134, which is coupled to the gearbox 122 in a ready-to-operate manner, drives the chains 130 and 132 by operating the final drive assemblies 104 and 118, as is known to those skilled in the art.

[0016] Fig. Figure 3 shows a schematic cross-sectional view of a section of the final drive assembly 104 of the Fig. 1 and the Fig. 2. During Fig. 3 the final drive arrangement 104 is located on the right side of the vehicle 100 Fig. As shown in Figure 1, the final drive assembly 118, which is located on the left side of the vehicle, has essentially the same configuration. Therefore, the discussion of the final drive assembly 104 applies equally to the final drive assembly 118.

[0017] How to Fig. As can be seen from Figure 3, the final drive assembly 104 is operationally connected to the gearbox 122 via a gearbox drive element 140. The gearbox drive element 140 functions as a gearbox coupling element or a gearbox output element, which couples the gearbox output shaft to the final drive assembly 104. The gearbox drive element 140 is operationally connected to the gearbox input shaft. A rotation of the gearbox shaft therefore drives the gearbox drive element 140 for rotation about a longitudinal axis 146 of the gearbox shaft. The gearbox drive element 140 serves as the output of speed and torque from the gearbox, and elements of the gearbox 122 are connected upstream which modify the speed and torque supplied to the gearbox drive element 140.

[0018] During initial assembly of the final drive assembly 104 with the body 102, the final drive assembly 104 is positioned in the cavity 106 and fastened to the body by the fasteners 110. The cavity 106 is arranged such that the final drive assembly 104 aligns a longitudinal axis 148 of a final drive element 150 with the longitudinal axis 146. In one embodiment, the final drive element corresponds to a gearbox or gear. Once aligned, the final drive element 150 is positioned to be operationally connected to the gearbox drive element 140 by means of a coupling device 152, which is located in a cavity 154 defined by the final drive element 150. The cavity 154 is generally cylindrical and, in the case of final drive gears, is defined by an inner surface with teeth 156 and a smooth surface 158.In one embodiment, the teeth 156 extend along approximately half of the generally cylindrical cavity, as shown. In other embodiments, the teeth extend along the longitudinal axis 148 for more or less than half the length of the inner cavity 154.

[0019] The coupling device 152 has a generally cylindrical final drive input shaft or a coupling shaft 160, which is shown in a first position 162 and in a second position 164. The coupling shaft 160 is arranged in the first position 162, which corresponds to a retracted or disconnected position to allow the gearbox 122 to be installed in the vehicle. While the coupling shaft 160 is in Fig. While the embodiment shown appears to have two parts, it has a single piece or a unified coupling shaft, with part of it shown in the first position 162 and part of it in the second position 164. An outer surface 166 has teeth 168 extending along the length of the coupling shaft 160 and engaging with the teeth 156 of the final drive element 150. Due to the cylindrical configuration of the coupling shaft 160, the teeth are arranged circumferentially around the outer surface of the coupling shaft 160. The connection of the gearbox 122 to either the final drive assembly 104 or the final drive assembly 118 is established by coupling the coupling shaft 160 to the gearbox drive element 140 and from there to the final drive element 150.

[0020] The coupling shaft 160 is designed to move longitudinally along the longitudinal axis 148 in the cavity 154 and longitudinally along the longitudinal axis 146 in a generally circular cavity 180, which is defined by the transmission drive element 140. An inner surface of the transmission drive element 140 has teeth 204, which are designed to engage with the teeth 168 of the coupling shaft 160. Once the teeth 168 of the coupling shaft 160 are fully engaged with the teeth 204, a connection between the transmission shaft and the final drive element 150 is fully established.

[0021] To ensure that the coupling shaft 160 engages fully with the transmission drive element 140, the coupling shaft 160 is driven along the longitudinal axis 148 by a drive-actuating device 184. The drive-actuating device 184 is driven by a tool (not shown) connected to a head 186 accessible through the access point 114. Removing the cap 116 from the access point 114 exposes an opening large enough for the tool to engage with the head 186. In one embodiment, the tool is a hexagonal tool designed to engage with a hexagonal head.

[0022] The head 186 is coupled to an actuating device 190 with teeth 192, which are designed to engage with teeth 194 of a drive element 196, such as a drive screw or follower screw. The actuating device 190 also has external teeth which engage with corresponding internal teeth of a retaining structure 197 at an interface 199. The actuating device 190 and the drive element 196 are constantly engaged by means of the associated teeth 192 and 194. Movement of the head / actuating device 186 / 190 along the axis 148 between the first position 201 and the second position 203 causes an actuating device tooth or wedge 192 to slide longitudinally along an associated drive element tooth or wedge 194, which is axially fixed.The drive actuating device 184 is shown in a first position 201 (the uppermost position is shown) and a second position 203 (the lowermost position is shown). In the first position 201, the engagement of the teeth at the interface 199 prevents rotation of the head 186. In this state, the position of the actuating device 190 is held by a resilient element, such as a spring 198, which directs the actuating device 190 to the right in the figure. To allow the actuating device 190 to rotate the drive element 196, the tool, which is engaged with the head 186, is moved with longitudinal pressure to the left in the figure to compress the spring 198 and to disengage the teeth of the actuating device 190 from the teeth of the retaining structure 197. In this position, the actuating device 190 (the lowest position 203 is shown) can be rotated.When the spring 198 is compressed, the rotation of the tool is therefore unrestricted and rotates the actuating device 190 and the drive element 196 about the axis 148, which moves the coupling shaft 160 along the axis 148 to engage with the gear drive element 140. More precisely, it moves as shown in... Fig. Figure 3 shows a rotation of the drive element 196 of the coupling element / nut 200, which moves the coupling shaft 160 either via the spring 206, when it is moved to the left to be connected, or via a stop 210 to the right in a separation direction. In one embodiment, the spring is a cylindrical spiral compression spring.

[0023] In the embodiment of the Fig. 3. The drive element 196 moves the coupling shaft 160 by moving a coupling element 200, which is also identified as a nut 200. The coupling element 200 is arranged between the drive element 196 and the coupling shaft 160. The drive element 196 has a helical thread which engages with a helical thread of the coupling element 200 at an interface 205. The coupling element 200 is also locked circumferentially with respect to the coupling shaft 160 by means of a tooth interface 202. The drive element 196 is held axially / longitudinally to limit its displacement to the left or right along the axis 148.Since the coupling element 200 cannot rotate relative to the coupling shaft 160, and since the drive element 196 cannot move, a rotation of the drive element 196 moves the coupling element towards the transmission drive element 140. Thus, when the coupling element engages with the coupling shaft 160, the coupling shaft 160 moves towards the transmission drive element 140, causing the teeth 168 to engage with the teeth 204 of the transmission drive element 140. After the teeth 168 are fully engaged with the teeth 204, the transmission drive shaft is coupled to the final drive element 150 to drive the chains 130.

[0024] A rotation of the head / actuating device 186 / 190 causes the threaded shaft (of the drive element) 196 to rotate by sliding, but with a tooth connection between the corresponding teeth 192 and 194 always engaged. The drive element 196 does not move axially / longitudinally to the left or right, as shown. The nut 200 moves along the axis 148 to the left or right by means of the threads of the nut 200 and the shaft 196 at an interface 205.

[0025] A compliant element or spring 206 is arranged between the coupling shaft 160 and the drive element 196. The spring 206 is compressed by the coupling element 200 between a first stop 208 and the coupling element / nut 200. To accommodate the compression of the spring 206, the coupling element can slide longitudinally along the axis 148 at the tooth interface 202 without disengaging circumferentially from the coupling shaft 160. The stop 210 is directly loaded by the movement of the nut 200, while the toothed coupling shaft 160 is disengaged (disengaged) from the inwardly toothed gear output part 140. The spring 206 stores the potential energy when the coupling shaft 160 is not properly aligned with the gear drive element 140, the misalignment of which prevents a sliding tooth engagement of the teeth 168 and 204.The alignment of teeth 168 and 204 is achieved through a relative movement between the gear drive element 140 and the coupling shaft 160. Typically, a slight circumferential rotation of the gear drive element 140 allows the spring 206 to release energy, resulting in an engagement of the gear teeth between the gear drive element 140 and the coupling shaft 160. The final drive element 150 and the gear drive element 140 move from a non-aligned circumferential position to an aligned position, enabling the coupling shaft 160 and the gear drive element 140 to fully engage.

[0026] While the spring 206 assists in aligning the coupling shaft 160 with the transmission drive element 140, the drive actuation device 184 in another embodiment, as shown in Fig. As shown in Figure 4, there is no coupling element 200, no spring 206, no first stop 208, and no second stop 210. In this configuration, a drive element 212, such as a drive screw, which is rotated by the head 186, has a helical thread that engages with a helical thread of a coupling shaft 214 at an interface 216. A rotation of the drive element 212 therefore moves the coupling shaft 214 to the gear drive element 140. In this embodiment, there is no alignment support mechanism, and consequently, a connection and / or disconnection between the coupling shaft 214 and the gear drive element 140 is effected by a rotation of the head 186, which moves the coupling shaft 214 to the gear drive element 140.A locked alignment of the coupling shaft 214 and the transmission drive element 140 is achieved by a circumferential movement (rotation) of either the transmission drive element 140 or the final drive element 150. Relative circumferential movement of the transmission drive element 140 and the final drive element 150 can be performed by starting the engine to provide engine power to the transmission's steering system and to provide a slight steering movement at the output shaft.

[0027] The presentation of Fig. Figure 4 shows the coupling shaft 214 in a disengaged position 218 and in a fully engaged position 220. As previously mentioned with reference to Fig.As described in Figure 3, the coupling shaft is generally a cylindrical single piece or a single coupling shaft. The coupling shaft 214 moves along a longitudinal axis 222. The coupling shaft 214 is arranged in the first position 218, which is a fully retracted or disengaged position to allow installation of the transmission 122 in the vehicle. In the second position 220, the coupling shaft 214 is fully engaged with the transmission drive element. An outer surface of the coupling shaft 214 has teeth 224 that extend along the length of the coupling shaft 214 and that engage with the teeth 156 of the final drive element 150 and the teeth 204 of the transmission drive element 140.

[0028] Under certain conditions, in which the vehicle 100 no longer moves under its own power, for example due to a fault in the engine or transmission, the final drive element 150 is disconnected from the transmission drive element 140 (if it was connected). To disconnect the final drive element 150 from the transmission drive element 140, the head 186 is turned with a tool in a direction opposite to the direction previously used to connect the coupling shaft 160 or the coupling shaft 214 to the transmission drive element 140. Once disconnected, the vehicle 100 is towed to another location where repairs can be carried out. After the repair, the coupling shaft 160 or the coupling shaft 214 is moved into engagement with the transmission drive element 140 to connect the final drive element 150 of the final drive transmission to the coupling shaft 160.

[0029] A connection between a transmission output and a final drive or gearbox mounted on the vehicle is generally independent of the transmission's installation in the vehicle. Therefore, the present disclosure provides a simple and straightforward connection of the power transmission elements without causing damage after the transmission is fully installed. Similarly, it provides a means of separating the drive elements from one another to allow for removal of the transmission or towing of a disabled vehicle without damaging non-functional drive elements. Furthermore, the toothed shaft 160 is actively locked either in the "engaged" position (the coupling shaft 160 is fully engaged with the transmission drive element 140) or in the "disengaged" position (the coupling shaft 160 is fully disengaged from the transmission drive element 140).The revelation provides all these functions and features in a compact, simple, and robust mechanism.

[0030] While exemplary embodiments incorporating the principles of the present invention have been previously disclosed, the present invention is not limited to these disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention that employ its general principles. Furthermore, this application is intended to cover such deviations from the present disclosure as are within the known or customary practice of the prior art to which this invention relates and which are within the limits of the appended claims.

Claims

[1] Vehicle drive train configured to propel a vehicle (100) with a traction element (130, 132) engaging with a surface, the drive train comprising: a gearbox (122) with a gearbox coupling element (140); a final drive arrangement (104, 118) configured to drive the traction element (130, 132) engaging with a surface, wherein the final drive arrangement (104, 118) has a drive element (150) spaced apart from the transmission coupling element (140) to create a gap between to define the drive element (150) and the transmission coupling element (140); and a coupling device (152) which is at least partially arranged in and coupled to the drive element (150), wherein the coupling device (152) in a first position (162) does not extend over the gap, so that the drive element (150) and the gear coupling element (140) are not connected by the coupling device (152), and in a second position (164) extends from the drive element (150) to the gear coupling element (140) over a distance sufficient to extend over the gap in order to connect the drive element (150) to the gear coupling element (140) in a ready-to-use manner, wherein the coupling device (152) comprises a coupling shaft (160) with dimensions sufficient to extend over the gap, and a drive actuation device (184) which is coupled to the coupling shaft (160) in a ready-to-operate manner, wherein the drive actuation device (184) is designed to move the coupling shaft (160) along a longitudinal axis (148) of the coupling device (152) over a distance sufficient to extend over the gap and to engage the transmission coupling element (140) with the drive element (150), wherein the coupling shaft (160) has external teeth (168) which are designed to engage with internal teeth (204) of the transmission coupling element (140) in the second position (164), and wherein the coupling shaft (160) is designed to move, when the coupling shaft (160) moves from the first position (164) to the second position (164) along the longitudinal axis (148) into a cavity (180) defined by the transmission coupling element (140), wherein the drive actuation device (184) further comprises a linear actuating part (196) which is coupled in an operational state to the coupling shaft (160) and to the drive element (150), wherein the linear actuating part (196) is configured to move the coupling shaft (160) along the longitudinal axis (148); and remains at a fixed position along the longitudinal axis (148) during a movement of the linear actuating part (196), wherein the drive actuation device (184) has a user-accessible drive which is operationally connected to the linear actuating part (196), wherein the user-accessible drive has a first position (201) which prevents the drive from moving the coupling shaft (160) along the longitudinal axis (148), and a second position (203) which allows, that the linear actuating part (196) moves the coupling shaft (160) along the longitudinal axis (148), and wherein the user-accessible drive has a preloading element (198) which is located between a section of the user-accessible drive and the linear actuating element (196), wherein the preloading element (198) has a first state to preload the user-accessible drive into the first position (201) and a second state to preload the user-accessible drive into the second position (203). [2] Vehicle powertrain according to claim 1, wherein the coupling shaft (160) has a thread which is configured to engage with the linear actuating part (196), and wherein the user-accessible drive is configured to rotate the linear actuating part (196) to move the coupling shaft (160) along the longitudinal direction (148) to connect the drive element (150) to the transmission coupling element (140) and to disconnect the drive element (150) from the transmission coupling element (140). [3] Vehicle powertrain according to claim 1 or claim 2, wherein a rotation of the user-accessible drive in a first direction connects the drive element (150) to the transmission coupling element (140). [4] Vehicle powertrain according to one of claims 1-3, wherein a rotation of the user-accessible drive in a second direction separates the drive element (150) from the transmission coupling element (140). [5] Vehicle powertrain according to one of claims 1-4, wherein the user-accessible drive has a user interface (186) which is arranged at an externally accessible location on the vehicle (100) to provide direct access to the user interface (186) without disassembling the vehicle's (100) powertrain. [6] Vehicle powertrain according to one of claims 1-5, wherein the linear actuating part (196) has a drive screw which is configured to engage with a thread of the coupling shaft (160) or with a nut (200) associated with the coupling shaft (160). [7] Vehicle drive train according to claim 6, wherein the drive actuation device (184) has a shaft preload element (206) located between the drive screw and the coupling shaft (160), wherein the shaft preload element (206) is configured to provide a preload force on the coupling shaft (160) along the longitudinal direction (148), wherein a movement of the drive screw towards the drive element (140) increases the preload force in the case that the coupling shaft (160) and the drive element (140) are misaligned in the circumferential direction.

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