Clutch engagement system based on an axially displaceable sleeve and a radially displaceable key

Abstract

Clutch engagement system of a transmission system, comprising: a sleeve (202) which is axially movable; a first output disk (212) in a first position; a second output disk (222) in a second position and a radially displaceable key (302) extending from the sleeve and configured to engage individually with each of the first output disk and the second output disk.

Description

TECHNICAL FIELD

[0001] This description relates generally to a clutch engagement system and, more particularly, to a clutch employing an engagement mechanism based on interlocking keys. BACKGROUND AND SUMMARY

[0002] In the automotive industry, claw clutches are used in certain vehicle platforms to couple rotating shafts and / or rotating components by meshing beveled teeth rather than using friction. The engagement of the claw clutch can be based on the angular alignment of the beveled teeth, generating high torque. Relying on the angular alignment of the bevels under such conditions can lead to issues with claw clutch engagement, such as jamming.

[0003] Some clutch engagement systems employ a dog clutch, which includes a piston that engages the beveled teeth and corresponding beveled tooth recesses when the piston is activated by hydraulic pressure, and a piston recess that receives a piston spring when hydraulic pressure is released, thereby disengaging the beveled teeth from the corresponding tooth recesses. In this manner, the dog clutch can be engaged and disengaged. However, the piston recess can lead to an imbalance between the opposing surfaces of the piston, which can be exacerbated by high centrifugal forces causing a buildup of hydraulic fluid. Consequently, piston pressure may follow a non-linear relationship, and the non-linearity can reduce the accuracy of piston control and, consequently, lead to engagement problems. US 9,358,866, B2 to Hartz et al.discloses a clutch engagement system in which the piston has an offset section that allows both sides of the piston to have the same area and diameter to improve piston control. The clutch hydraulics also incorporate an overrun function to reduce hydrostatic clutch locking.

[0004] The inventors identified several drawbacks with the Hartz clutch engagement system, as well as other previous clutch engagement systems. With the Hartz clutch engagement system, the piston can be difficult to manufacture. Furthermore, the Hartz clutch engagement system relies on hydraulic fluid control to prevent jamming and does not address engagement issues due to the relative positioning of the clutch components.

[0005] The problems described above can be at least partially solved by a clutch engagement system of a transmission system comprising an axially movable sleeve, a first output disc in a first position, a second output disc in a second position, and a radially displaceable key extending from the sleeve and configured to individually engage each of the first output disc and the second output disc. In this way, clutch locking can be prevented by using an engagement mechanism in which the clutch relies on axial movement of the sleeve to depress the radially displaceable key, with the radially displaceable key being extended into an internal cavity to engage the sleeve and one of the first output disc or the second output disc.

[0006] It should be understood that the above summary is intended to introduce, in simplified form, a selection of concepts that are further explained in the detailed description. It is not intended to identify the most important or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages noted above or elsewhere in this disclosure. SHORT DESCRIPTION OF THE CHARACTERS

[0007] The present disclosure will be better understood by reading the following description of non-limiting embodiments with reference to the accompanying drawings, which are set out below: Fig. 1 schematically shows a vehicle according to one or more embodiments of the present disclosure; Fig. 2 shows a schematic cross-sectional view of a clutch engagement system according to one or more embodiments of the present disclosure; Fig. 3 shows a schematic representation of a sleeve of a clutch engagement system according to one or more embodiments of the present disclosure; Fig. 4 shows a schematic representation of an output disc of a clutch engagement system according to one or more embodiments of the present disclosure; Fig. 5 is a flowchart illustrating an exemplary method for engaging and disengaging a dog clutch of a clutch engagement system according to one or more embodiments of the present disclosure; Fig. 6A illustrates an example of a clutch engagement system in a neutral position in accordance with one or more embodiments of the present disclosure; Fig. 6B illustrates an example of a clutch engagement system in a first engaged position according to one or more embodiments of the present disclosure; Fig. 6C shows an example of a clutch engagement system in a second engagement position; and Fig. 7 shows a schematic diagram of a clutch engagement system integrated into an exemplary transmission system in accordance with one or more embodiments of the present disclosure.

[0008] The drawings illustrate specific aspects of the described systems and methods. Together with the following description, the drawings demonstrate and explain the structures, methods, and principles described herein. In the drawings, the size of components may be exaggerated or otherwise modified for clarity. Well-known structures, materials, or functions are not shown or described in detail to avoid obscuring aspects of the described components, systems, and methods. DETAILED DESCRIPTION

[0009] The following description relates to systems and methods for a clutch engagement system of a vehicle, such as that described in Fig. 1. The clutch engagement system may comprise a dog clutch that couples one or more gears of a transmission system via one or more output discs, as shown in Fig. 2. The clutch engagement system may further comprise a sleeve that can be selectively coupled to an output disc via two or more keys, as in Fig. 3 shown. Fig. Figure 4 shows the output disc, which can be optionally connected to the sleeve. A method for engaging and disengaging the clutch engagement system is described in Fig. 5 described. Fig. Figure 6A shows a dog clutch in a neutral position, not engaging an output disc. Examples of dog clutch engagement with an output disc are shown in Fig. 6B and Fig. 6C. The integration of the clutch engagement system is shown in Fig. 7 shown.

[0010] Fig. 1 shows a vehicle 100. The vehicle 100 may be a light, medium, or heavy-duty commercial vehicle. The vehicle 100 includes an electric drive unit 102. Thus, the vehicle 100 may be an electric vehicle (e.g., a pure electric vehicle or a hybrid electric vehicle with an internal combustion engine) or a conventional internal combustion engine vehicle. In particular, the electric drive unit 102 may supply motive power to one or more drive axles 140. In one application, the electric drive unit 102 may, for example, include two electric axles with separate traction motors. Alternatively, the electric drive unit 102 may also include a traction motor that distributes the motive power to one or both drive axles depending on the operating conditions of the vehicle and / or the driver's preference. In both examples, the electric drive unit 102 may be an electric four-wheel drive (e.g.,An electric all-wheel drive system (e.g., an electric all-wheel drive system) in which the front and rear drive wheels can be driven under certain operating conditions. When implemented as a hybrid vehicle, the vehicle 100 may include one axle driven by an electric motor and another axle driven by an internal combustion engine during driving operation. In other examples, the electric drive unit may also be incorporated into a front-wheel drive drivetrain or a rear-wheel drive drivetrain.

[0011] The electric drive unit 102 includes a prime mover 104 (e.g., an electric motor, an internal combustion engine, and the like) mechanically coupled to a transmission 106. In the electric vehicle example, the electric motor may be a permanent magnet (PM) motor or, more generally, an alternating current (AC) motor. In such an example, the prime mover 104 receives electrical energy from an inverter 110, which in turn receives electrical energy from one or more energy storage devices 112 (e.g., traction batteries, capacitors, combinations thereof, and the like). Arrows 150 indicate the mechanical power transfer between the prime mover 104 and the transmission 106.Arrows 152 indicate the electrical power transfer between the prime mover 104 and the inverter 110, and arrows 154 indicate the electrical power transfer between the inverter 110 and the energy storage device(s) 112. A clutch engagement system comprising a sleeve with two or more keys and two or more springs may be integrated as part of the transmission 106 to transfer power to various reduction gears of the transmission 106. Mechanical power may be transferred from the transmission 106 to the one or more drive axles 140 via a differential 114.

[0012] The vehicle 100 further includes a control system 170 having a controller 172 (e.g., an electronic control unit (ECU) such as a transmission control unit (TCU), a vehicle control unit (VCU), combinations thereof, and the like). The controller 172 may be configured to implement control strategies. To achieve the aforementioned vehicle control functionality, the vehicle control unit may include a memory 174 that stores instructions executable by a processor 176 to execute the vehicle control strategies.

[0013] One or more input devices 178, such as a drive mode selector, an accelerator pedal, a brake pedal, a touch interface, combinations thereof, etc., may be in electronic communication with the controller 172, as represented by arrows 180. The drive mode selector may be a button, a switch, a touch interface, a slider, or a combination thereof that allows the vehicle operator to initiate the disengagement of the transmission 106 from the drive wheels. For example, the drive mode selector may allow the vehicle to shift from a two-wheel drive to a four-wheel drive mode if the vehicle has a second electric axle. The controller 172 may control one or more components of the vehicle 100 via one or more actuators 179. For example, one actuator of the one or more actuators 179 may control the disengagement of the transmission 106 from the drive wheels.

[0014] An axis system 199 is in Fig. 1 is provided for reference. In one example, the z-axis may be a vertical axis (e.g., parallel to a gravitational axis), the x-axis may be a lateral axis (e.g., a horizontal axis), and / or the y-axis may be a longitudinal axis. However, in other examples, the axes may have other orientations.

[0015] Fig. 2 shows an example of a clutch engagement system 200 of a vehicle, such as the vehicle 100 of Fig. 1. In particular, the clutch engagement system 200 may be integrated into the transmission 106 of Fig. 1. The clutch engagement system 200 may include a clutch having a sleeve 202, a first output disc 212 in a first position, and a second output disc 222 in a second position. The sleeve 202, the first output disc 212, and the second output disc 222 may be coaxial and rotatable. The sleeve 202 may be axially movable so that the sleeve 202 can be aligned with the first output disc 212 and the second output disc 222. The first output disc 212 may be adjacent to the second output disc 222 and positioned with sufficient axial clearance between a side 230 of the first output disc and a side 232 of the second output disc to allow the first output disc and the second output disc to rotate independently of each other.The first output disc 212 may also have an inner diameter that is larger than the outer diameter of both the sleeve 202 and the second output disc 222, and the second output disc 222 may have an inner diameter that is larger than the outer diameter of the sleeve 202. Thus, the first output disc 212 may circumferentially surround the sleeve 202 at a first position, while the second output disc 222 may circumferentially surround the sleeve 202 at a second position, wherein the first position is different from the second position. In this way, the second output disc 222 may be recessed into a space between the sleeve 202 and the first output disc 212, and the first output disc 212 may circumferentially surround both the sleeve 202 and the second output disc 222.

[0016] A length of side 230 of the first output plate 212 may also exceed a length of side 232 of the second output plate 222. However, the length of side 230 abruptly decreases by a length of side 232 so that the first output plate 212 and the second output plate 222 can be arranged side by side. In this way, an inner surface 224 of the first output plate 212 and an outer surface 226 of the second output plate 222 can be adjacent to one another. A position of the sleeve 202 relative to a centerline 228 of the clutch engagement system may allow the sleeve to be selectively coupled to the first output plate 212 or the second output plate 222. The position of the sleeve 202 at the centerline 228 may be considered the neutral position of the sleeve.By axially adjusting the position of the sleeve 202 relative to the neutral position of the sleeve, the sleeve 202 can be selectively coupled to one of the first output disc 212 and the second output disc 222 by a radially displaceable key, such as a first key 216, extending from the sleeve and configured to individually engage each of the first output disc and the second output disc.

[0017] The sleeve 202 may further include a first outer cavity 206 of two or more outer cavities, the first key 216 of two or more keys, a first spring 214 of two or more springs, and internal teeth 204. In some embodiments, two or more external cavities may include only two external cavities, two or more keys may include only two keys, and two or more springs may include only two springs. In other embodiments, two or more external cavities may include three external cavities, two or more keys may include three keys, and two or more springs may include three springs.

[0018] Each wedge may have a pair of parallel beveled surfaces, e.g., a first beveled surface 216a and a second beveled surface 216b, and may extend from an outer cavity, e.g., the first outer cavity 206, of the sleeve 202. The first output disc 212 and the second output disc 222 may both have a plurality of inner cavities and an inner groove (not shown). The plurality of inner cavities may be disposed along an inner surface 220 of the first output disc 212 or an inner surface of the second output disc 222. For example, the second output disc 222 may have an inner cavity 218a and an inner cavity 218b disposed along the inner surface 220 of the second output disc 222.Each outer cavity of the sleeve 202 of the two or more outer cavities may include a first portion 208 and a second portion 210, wherein the first portion and the second portion are adjacent to each other.

[0019] The inner teeth 204 may be arranged to mesh with a rotating element of the transmission system of a vehicle to transmit power from a prime mover, such as prime mover 104 in Fig. 1. Each key can be positioned in the first section 208 and each spring in the second section 210. In this way, upon rotation of the sleeve 202, each spring can press against a key and extend the key to selectively connect the key to the first output disc 212 or the second output disc 222 when the sleeve 202 is not in the neutral position. In this way, the sleeve 202 can be selectively coupled to the first output disc or the second output disc without requiring an actuator to apply a high axial load to align chamfered teeth of existing clutch engagement systems, which can reduce the manufacturing cost of the transmission system.

[0020] In one example, the first spring 214 may be positioned in the second portion 210 of the first outer cavity 206, while the first key 216 may be positioned in the first portion 208. The first spring 214 may push against the first button 216 to connect the first button 216 to either the first output disc 212 or the second output disc 222. More specifically, when the sleeve 202 rotates (e.g., following axial movement of the sleeve to the second position), the first key 216 may be within a clearance threshold of an inner cavity 218a, and by extending the first key 216, the first key and the inner cavity may engage, thereby selectively coupling the sleeve 202 and the second output disc 222. However, if the sleeve 202 is in the neutral position, neither the first output disc 212 nor the second output disc 222 are connected to the sleeve.Instead, as the sleeve 202 rotates, each spring can press against a key and extend the key so that the key engages the inner grooves of the first output disc 212 and the second output disc 222.

[0021] Fig. 3 shows an example of a sleeve 300 of a clutch engagement system, such as the clutch engagement system 200 of Fig. 2. The sleeve assembly 300 may share at least some of the structural and functional features with the sleeve 202 of Fig. 2 in common. Therefore, the redundant description of these overlapping features can be omitted for the sake of clarity.

[0022] The sleeve assembly 300 includes a key 302 and a sleeve 308. Each key 302 includes a key head 304 and a key shank 306. The shape of the key head 304 may be a chamfered rectangular prism, wherein the chamfered rectangular prism is a rectangular prism in which two parallel surfaces of the rectangular prism are chamfered. For example, each key head 304 may have a first chamfered surface 304a and a second chamfered surface 304b and extend from the sleeve 308. Each spring of the clutch engagement system 200 of Fig. 2 can be coupled to the key shaft 306.

[0023] The sleeve 308 is provided with a grooved portion 312, an end portion 310, and internal teeth 322 located on an inner surface of the sleeve 308 and extending from the end portion 310 to one end of the grooved portion 312. The grooved portion 312 includes grooves connecting the sleeve 308 and a fork drive. The end portion 310 includes two or more external cavities. Each external cavity may be disposed along an outer surface of the end portion 310 of the sleeve 308 and extend radially from the outer surface of the end portion 310 of the sleeve 308 toward an inner diameter of the sleeve. Furthermore, each external cavity may be disposed equidistant from one another on the outer surface of the end portion 310 of the sleeve 308. The two or more external cavities may include a first external cavity 314a, a second external cavity 314b, and a third external cavity 314c.Each key 302 can protrude from the first outer cavity 314a, the second outer cavity 314b, and the third outer cavity 314c of the sleeve 308.

[0024] Each external cavity may include a first portion 316 and a second portion 318. The first portion 316 may have a square or rectangular cross-section, and the second portion 318 may have a circular cross-section. The first portion 316 and the second portion 318 are adjacent to each other, and the first portion 316 merges into the second portion 318 at an interface 320 between the first portion and the second portion.

[0025] Fig. 4 shows an example of an output disc 400 of a clutch engagement system, such as the clutch engagement system 200 of Fig. 2. The output disk 400 may share at least some of the structural and functional features with the output disks (e.g., the first output disk 212 and the second output disk 222) of Fig. 2 in common. Therefore, the redundant description of these overlapping features can be omitted for the sake of clarity.

[0026] The output disk 400, which may be the first output disk 212 or the second output disk 222, may include a plurality of internal cavities 410 and an internal groove 412 located on an internal surface 408 on one side of the output disk 400, and internal teeth 406 arranged to mesh with a gear shaft on another side of the output disk 400. The internal teeth 406 are included in a first portion 402 of the output disk 400 and may extend from one end of the output disk 400 along a first length of the output disk 400. The plurality of internal cavities 410 and the internal groove 412 may be included in a second portion 404 of the output disk 400 that extends from one end of the first length of the output disk 400 to the other end of the output disk. The internal groove 412 may be located at the other end of the output disk 400.The plurality of internal cavities 410 may be disposed on an internal surface 408 of the output disk 400 and between the end of the first length of the output disk 400 and the internal groove 412. Each internal cavity may have a rectangular shape and be equidistantly spaced from another internal cavity by a portion of the internal surface 408. A lateral surface 414 of the internal groove 412 has the same angle as the beveled key heads of FIG. Fig. 3, which allows the lateral surface to act as a ramp. Fig. The keys described in Figure 3 can be pushed inward when the sleeve is axially displaced and a bevelled surface of the key presses against a lateral surface of the inner groove of an output disc, e.g. a first output disc or a second output disc.

[0027] Fig. 5 shows an example method 500 for operating a clutch engagement system in a transmission system such as that described above with reference to Fig. 2, in one example. The method 500 may be executed by a controller and stored as instructions in a memory. The instructions for performing the method 500 may be executed by the controller in conjunction with signals received from sensors of the vehicle, such as the sensors described above with reference to Fig. 1. The controller may use actuators of the system to adjust the operation of the system according to the method described below.

[0028] At 502, method 500 includes receiving output signals from sensors indicating that a speed difference between a sleeve and a first output disc is within a threshold, wherein the speed of the first output disc is nearly the same as the speed of the sleeve. Rotation of the sleeve may occur when torque is transmitted to the sleeve via a gear shaft connected to both a prime mover, such as prime mover 104 in Fig. 1, and is connected to the sleeve. The sleeve and the gear shaft can be coupled when the internal teeth mesh with the gear shaft. Torque can be transmitted from the motor to the sleeve via the gear shaft when the gear shaft rotates. In this way, torque can be transmitted from the motor to the first output disc when the sleeve is selectively coupled to the first output disc.

[0029] A sensor connected to the sleeve can monitor the speed of the sleeve as it rotates. Similarly, a sensor communicating with the first output disc can monitor the speed of the first output disc. In this way, a speed difference between the sleeve and the first output disc can be determined based on the data received from the sensors. The speed difference can be a relative speed difference between the sleeve and the first output disc or the sleeve and the second output disc. When the speed difference is within the speed difference threshold, or when the speed of the first output disc and the sleeve are nearly identical, an actuator can be used to adjust the position of the sleeve so that the sleeve and the first output disc mesh. In some embodiments, the actuator can be a fork actuator.

[0030] At 504, method 500 includes axially displacing the sleeve of a clutch from a neutral position to a first position using an actuator. To axially move the sleeve, an actuator can be sized based on the spring forces generated by the two or more keys. In this way, the actuator can be sufficiently sized to overcome the spring forces generated by the two or more keys, which may impede the axial movement of the sleeve upon activation.

[0031] Before axially displacing the sleeve of the clutch, the sleeve can be selectively disengaged from a first output disc in a first position or a second output disc in a second position when the sleeve is in a neutral position. In a clutch engagement system in which the first output disc is located to the left of a neutral position and the second output disc is located to the right of the neutral position (e.g. similar to the clutch engagement system of Fig. 2), the sleeve can be moved from the neutral position to a first position by axially shifting it to the left.

[0032] In response to the axial movement of the sleeve from the neutral position to the first position, a radially displaceable key of the sleeve, urged inward (e.g., with a compressed coil spring), can be moved axially from the neutral position to the first position. Once in the first position, the radially displaceable key can extend outward (e.g., the coil spring expands) to engage the first output disc and the sleeve.

[0033] At 506, method 500 includes rotating the sleeve in the first position to allow a key to engage an internal cavity and extend into the internal cavity of the first output disk. As described herein, the sleeve is rotatable. In some embodiments, the sleeve may be stationary when the sleeve is moved axially and begin rotating once the sleeve is in the first position. In other embodiments, the sleeve may rotate when the sleeve is moved axially to the first position.

[0034] Spring forces may be generated by a spring coupled to the key, and the spring forces may cause the spring to press against the key shank of the key, allowing the position of the key to be radially adjusted and the key to be extended. Rotation of the sleeve may cause the position of the key relative to the internal cavity to change over time, so that the key may be positioned within the distance threshold of the internal cavity of the first output disc at different times. Within the distance threshold, the two or more keys may extend into two or more internal cavities of the first output disc, with each key extending into an internal cavity. An example of a sleeve connected to the first output disc is shown in Fig. 6B.

[0035] At 508, method 500 includes axially translating the sleeve from the first position to the neutral position using an actuator. Prior to axially translating the sleeve of the clutch, the sleeve is selectively connected to the first output disc in the first position. By axially translating the sleeve to the right of the first position, the sleeve may be moved from the first position to the neutral position. In response to the axial movement of the sleeve from the first position to the neutral position, a radially movable key of the sleeve, which is elongated and engages the internal cavity, may be moved axially from the first position to the neutral position.

[0036] The axial movement of the sleeve can cause an axial displacement of the key. In this way, the radially displaceable key and thus the sleeve can be released from the first output disc. By releasing the key, the sleeve is no longer coupled to the first output disc and the transmission of torque from the engine to the first output disc is terminated. In this way, two or more keys of the clutch engagement system can be disengaged from two or more internal cavities of the first output disc when the sleeve is moved axially from the first position to the neutral position. An example of the neutral position of the sleeve is shown below using Fig. 6A. By relying on the axial movement of the sleeve to depress the key and the key-coupled spring and push the key into the internal cavities of the first output disc, the engagement of the sleeve with the first output disc prevents clutch lockup due to the relative positioning of the various clutch components (e.g., chamfered teeth), drag torque, and the like.

[0037] In the neutral position, the sleeve cannot be selectively coupled to a first or a second output disc. The inability to couple may be due to a key of the sleeve being in the internal groove of the first output disc and the second output disc and not being within a clearance threshold of an internal cavity of the first output disc or the second output disc when the sleeve rotates. The key cannot be inserted into the internal cavity if it is not within the clearance threshold. When the sleeve is in the neutral position, the key rotates in the internal grooves of the first output disc and the second output disc. Because the key rotates in the internal grooves of the first output disc and the second output disc, neither the first output disc nor the second output disc are selectively connected to the sleeve.As shown here, the position of the sleeve can be adjusted so that the key is within the distance threshold to the internal cavity.

[0038] At 510, method 500 includes receiving output signals from sensors indicating that a speed difference between the sleeve and a second output disk is within a threshold, wherein the speed of the second output disk is nearly the same as the speed of the sleeve. The sensor connected to the sleeve may monitor the speed of the sleeve while the sleeve rotates. Similarly, a sensor in communication with the second output disk may monitor the speed of the second output disk. In this way, a speed difference between the sleeve and the second output disk may be determined based on the data received from the sensors. The speed difference may be a relative speed difference between the sleeve and the second output disk. If the speed difference is within the speed difference threshold, orIf the rotational speeds of the second output disc and the sleeve are nearly identical, an actuator may be used to adjust the position of the sleeve so that the sleeve and the second output disc mesh. In some embodiments, the actuator may be a fork actuator.

[0039] At 512, method 500 includes axially translating the sleeve of a clutch from the neutral position to the second position using an actuator. Prior to axially translating the sleeve of the clutch, the sleeve may be selectively coupled to the first output disc in the first position or to the second output disc in the second position when the sleeve is in the neutral position. By axially translating the sleeve to the right of the neutral position, the sleeve may be moved from the neutral position to the second position. In response to the axial movement of the sleeve from the neutral position to the second position, a radially movable key of the sleeve, urged inwardly (e.g., with a compressed coil spring), may be axially moved from the neutral position to the second position.Once the radially displaceable key is in the second position, the radially displaceable key can extend outward (e.g., the coil spring expands) to engage the second output disc and the sleeve.

[0040] At 514, method 500 includes rotating the sleeve in the second position to allow a key to encounter an internal cavity and extend into the internal cavity of the second output disk. As described herein, in some embodiments, the sleeve may be stationary when the sleeve is moved axially and begin rotating once the sleeve is in the second position. In other embodiments, the sleeve may rotate when the sleeve is moved axially to the second position. Spring forces may be generated by a spring coupled to the key, and the spring forces may cause the spring to push against the key shank of the key, allowing the position of the key to be radially adjusted and the key to be extended.Rotation of the sleeve can cause the position of the key relative to the internal cavity to change over time, so that the key can be positioned within the distance threshold of the internal cavity of the second output disc at different times. Within the distance threshold, the two or more keys can extend into the two or more internal cavities of the second output disc, with each key extending into an internal cavity. An example of a sleeve connected to the second output disc is shown in FIG. Fig. 6C. By relying on the axial movement of the sleeve to depress the key and the key-coupled spring and push the key into the internal cavities of the second output disc, the engagement of the sleeve with the second output disc prevents clutch lockup due to the relative positioning of the various clutch components (e.g., chamfered teeth), drag torque, and the like. Method 500 then exits.

[0041] It is understood that the method 500 is exemplary and that other embodiments may vary without affecting the scope of the present disclosure. For example, the arrangement of the first output disc and the second output disc may differ such that upon axial movement to the left, the sleeve and the second output disc may be engaged with each other, and upon axial movement to the right, the sleeve and the first output disc may be engaged with each other, as is the case in the embodiments described herein. In particular, in another embodiment, the first output disc may be arranged in the second position and the second output disc may be arranged in the first position.

[0042] Fig. 6A-6C show schematic representations of a clutch engagement system of a transmission in a vehicle, such as the transmission 106 of Fig. 1 in a neutral position 600, a first engaged position 601 and a second engaged position 603. Fig. Figures 6A -6C provide an overview of how a clutch can be engaged when it is initially in a neutral position.

[0043] The clutch engagement system of Fig. 6A-6C, an embodiment of the clutch engagement system 200 of Fig. 2. The clutch engagement system of the Fig. 6A-6C may include a clutch comprising a sleeve 602 that is axially movable and rotatable and provided with two or more keys and two or more springs, and a first output disc 612 in a first position and a second output disc 622 in a second position that are rotatable and provided with internal teeth arranged to mesh with a rotating element of the transmission, a plurality of internal cavities, and an internal groove (not shown). The first output disc 612 or the second output disc 622 may be selectively connected to the sleeve 602. The sleeve 602 may be selectively connected to the first output disc 612 or the second output disc 622 by axially adjusting a position of the sleeve to connect the two or more keys to the first output disc or the second output disc.A dashed line 618 may indicate a neutral or centered position of the sleeve 602. In some embodiments, the first output disc may be coupled to a carrier of a reduction gear, while the second output disc may be coupled to a pinion of the reduction gear.

[0044] More specifically, the clutch engagement system may include the sleeve 602, the first output disc 612, and the second output disc 622 in a similar arrangement as described above with respect to Fig. 2-4. The sleeve 602 may include internal teeth 604 arranged to mesh with a rotating element of the transmission (e.g., an input shaft), two or more outer cavities arranged on the outer surface of the sleeve, two or more keys, and two or more springs arranged within the two or more outer cavities. Each key may include a key head 610 and a key shank 610c. The key head may have beveled surfaces, e.g., a first beveled surface 610a and a second beveled surface 610b. In one embodiment, the clutch engagement system of Fig. 6A-6C include an outer cavity 616 enclosing a spring 606 coupled to a key shaft 608 via the key shaft 610c.

[0045] In Fig. 6A, the clutch engagement system is in the neutral position 600. The clutch engagement system may be in the neutral position 600 when the key 608 of the sleeve 602 is aligned with the dashed line 618. Based on the illustrated configuration of the clutch engagement system, the neutral position 600 may be achieved by axially translating the sleeve 602 from the first position to the right when coupled to the first output plate 612, or by axially translating the sleeve 602 from the second position to the left when coupled to the second output plate 622. Due to alignment of the key 608 of the sleeve 602 with the dashed line 618, the sleeve 602 may not be coupled to either the first output plate 612 or the second output plate 622 via the key 608.

[0046] The inability of the sleeve 602 to couple to the first output disc 612 or the second output disc 622 may be due to the key shank 608 being positioned in the internal grooves of the first output disc and the second output disc and not being positioned within a clearance threshold of an internal cavity of the first output disc or the second output disc when the spring 606 radially urges the key shank 608, and in particular, the key shank 610c. Accordingly, the two or more keys rotate in the internal grooves of the first output disc 612 and the second output disc 622 as the sleeve 602 rotates due to the torque transmitted from the motor to the sleeve via the transmission shaft. Thus, no torque is transmitted to the first output disc and the second output disc.

[0047] In Fig. 6B, the clutch engagement system is in a first engaged position 601. The clutch engagement system may be in the first engaged position 601 when the sleeve 602 is axially adjusted to the left of the dashed line 618. Based on the illustrated configuration of the clutch engagement system, the first engaged position 601 may be achieved by axially shifting the sleeve 602 to the left from the neutral position when it is not connected to either the first output disc 612 or the second output disc 622. By axially shifting the sleeve 602 to the left of the dashed line 618, the sleeve 602 may be coupled to the first output disc 612 because the key 608 can no longer be positioned in the internal groove and can be positioned within a clearance threshold of an internal cavity of the first output disc 612.In this way, the key 608 may extend into one of the plurality of internal cavities of the first output disk 612 when a speed difference threshold is met. In some embodiments, the one internal cavity may be the internal cavity 620a of the plurality of internal cavities, depending on the relative position of the internal cavity 620a while the sleeve 602 rotates.

[0048] For example, when the sleeve 602 rotates and the threshold speed difference between the sleeve 602 and the first output disk 612 is met, the forces generated by the compression of the spring 606 may cause the spring 606 to radially press against the button 608 of the sleeve 602 via the key shaft 610c as the sleeve is moved axially. The key 608 may then be moved radially toward and into one of the internal cavities, such as the internal cavity 620a. The key 608 may extend into the internal cavity 620a to lock the key 608 as the sleeve 602 rotates. In some embodiments, an actuator may be sized based on the forces generated by the spring 606. In this way, the actuator may have sufficient mechanical force to axially translate the sleeve 602 from the neutral position to the first position.

[0049] In Fig. 6C, the clutch engagement system is in a second engaged position 603. The clutch engagement system may be in the second engaged position 603 when the sleeve 602 is axially translated to the right of the dashed line 618. Based on the illustrated configuration of the clutch engagement system, the second engaged position 603 may be achieved by axially translating the sleeve 602 to the right of the neutral position when it is not coupled to either the first output disc 612 or the second output disc 622. By axially translating the sleeve 602 to the right of the dashed line 618, the sleeve 602 may be coupled to the second output disc 622 because the key 608 can no longer be positioned in the internal groove and can be positioned within a clearance threshold of an internal cavity of the second output disc 622.In this way, the key 608 may extend into an internal cavity of the second output disk 622 when the threshold speed difference between the sleeve 602 and the second output disk 622 is reached. In some embodiments, the one internal cavity may be the internal cavity 614a or the internal cavity 614b of the plurality of internal cavities, depending on the relative position of the internal cavity 614a and the internal cavity 614b as the sleeve 602 rotates.

[0050] For example, when the sleeve 602 rotates and the threshold speed difference between the sleeve 602 and the second output disk 622 is met, the forces generated by the compression of the spring 606 may cause the spring 606 to radially push against the button 608 of the sleeve 602 via the key shaft 610c as the sleeve is moved axially. The key 608 is then moved radially toward and into one of the internal cavities, such as the internal cavity 614a. The key 608 may extend into the internal cavity 614a to lock the key 608 and the internal cavity 614a as the sleeve 602 rotates. In some embodiments, an actuator may be sized based on the forces generated by the spring 606. In this way, the actuator can have sufficient mechanical force to axially move the sleeve 602 from the neutral position to the second position.

[0051] Fig. 7 shows an example of a clutch engagement system integrated into a portion 700 of a vehicle transmission, such as the transmission 106 of Fig. 1. The clutch engagement system of section 700 of the transmission may share at least some of the structural and functional features with the clutch engagement system of the Fig. 2-4 have in common. Therefore, for the sake of conciseness, a redundant description of these features, which are the same for both, is omitted here.

[0052] The clutch engagement system of section 700 may include a clutch having an axially movable sleeve 702 with two or more outer cavities, two or more keys, two or more springs, internal teeth arranged to mesh with a rotating element, a first output disc 712, and a second output disc 710 having a plurality of inner cavities, internal teeth arranged to mesh with a rotating element, and an internal groove. The sleeve 702, the first output disc 712, and the second output disc 710 may be coaxial. Furthermore, the second output disc 710 may circumferentially surround the sleeve 702, and the first output disc 712 may circumferentially surround the sleeve 702 and the second output disc 710.

[0053] The two or more external cavities (e.g., not shown) enclose the two or more springs connected to the two or more keys. For example, an external cavity (e.g., not shown) may enclose a spring 708 connected to a key 706. The key 706 may be one of the two or more keys, and the spring 708 may be one of the two or more springs. The key 706 of the sleeve 702 may individually engage an internal cavity of the first output disc 712 or the second output disc 710 and connect the sleeve 702 to the first output disc or the second output disc.

[0054] The portion 700 may further include a pinion 718 coupled to a first crown 716 of a first planetary gear unit. The first crown 716 may be disposed between the clutch and an output shaft 714. The first crown 716 may also be orthogonal to the input shaft 704. The input shaft 704 may extend in the axial direction and be coupled to a prime mover, such as prime mover 104 in Fig. 1. In this way, torque from the prime mover can be transmitted to the sleeve 702 via the input shaft 704. The output shaft 714 can be coupled to drive wheels. In some embodiments, the output shaft 714 can be coupled to the sleeve 702 via a differential, such as the differential 114 in Fig. 1, be connected to the wheels.

[0055] In some embodiments, when the sleeve 702 is moved axially, the spring forces generated by the inward pushing of the key 706 may be released to extend the key 706 and engage the key 706 with the internal cavity of one of the first output disc 712 and the second output disc 710. Once the sleeve 702 is in an engaged position according to the embodiments described herein with respect to the Fig. 6B and Fig. 6C, torque may be transmitted from the sleeve to one of the first output disc 712 and the second output disc 710. The portion 700 of the transmission system may include a second rim 722 of a second epicyclic unit adjacent to the sleeve 702, the second rim being located to the left of the sleeve.

[0056] When the sleeve 702 engages the first output disc 712, torque is transmitted from the sleeve to the first output disc 712, the first output disc being rigidly connected to a carrier of the planetary unit. The epicyclic unit may be rigidly connected to the output shaft 714. Due to the engagement of the sleeve 702 and the first output disc 712, the output shaft 714 rotates at the same speed as the sleeve. Conversely, when the sleeve 702 engages the second output disc 710, torque is transmitted from the sleeve to the second output disc 710, the second output disc being rigidly connected to the pinion 718 of the planetary gear set, which meshes with the satellites of a carrier. As shown in section 700, the first crown 716 of the planetary gear set is rigidly connected to a gear housing and therefore cannot rotate.However, in some embodiments, the output shaft 714 rotates at a lower speed than the sleeve when the sleeve 702 and the second output disc 710 are engaged, depending on the reduction ratio of the planetary gear set. In other embodiments, the first output disc 712 and the second output disc 710 may be coupled to other components of the transmission not included in the planetary gear unit.

[0057] It is understood that the embodiments described here can also be used in other transmission systems than the one in Fig. 7 described system can be integrated. The transmission system of Fig. 7 is exemplary and does not limit the scope of the present disclosure.

[0058] Compared to existing clutch engagement systems, the present disclosure is flexible in that it can be adapted to the spatial conditions of the transmission system and the desired torque transmission. In particular, the number of radially displaceable keys can be selected depending on the desired torque transmission. Furthermore, the present disclosure can be used in various transmission systems because the clutch engagement system is not dependent on specific or predetermined arrangements of keyways, tools, devices, and the like in a transmission system. Due to the simplicity of the clutch engagement system, the clutch engagement system described here can be used in transmission systems where standard gearing may cause manufacturing problems.

[0059] By implementing the clutch engagement system described herein in a portion, such as portion 700, of a transmission system, the clutch engagement system may prevent engagement problems common to existing clutch engagement systems, such as engagement problems due to relative position of parts, drag torque, and the like. For example, the present disclosure does not rely on engaging and disengaging beveled teeth and tooth recesses. Instead, the disclosure relies on adjusting the position of an axially movable sleeve to urge a key inward. By axially displacing the sleeve to a position different from the initial position, the key may be positioned within a distance threshold of an internal cavity of the first output disc or the second output disc.The spring forces generated by depressing the key and the key-coupled spring can be released to extend the radially displaceable key into an internal cavity. By relying on the axial movement of the sleeve to depress the key and the key-coupled spring and push the key into the internal cavities of the first output disc, clutch lockup due to the relative positioning of the various clutch components (e.g., chamfered teeth), drag torque, and the like cannot occur when the sleeve engages the first output disc or the second output disc.

[0060] A technical effect of implementing a clutch engagement system comprising an axially movable sleeve, a first output disc in a first position, a second output disc in a second position, and a radially displaceable key extending from the sleeve and configured to individually engage each of the first output disc and the second output disc is that locking of the clutch can be reduced. In particular, locking can be reduced by axial movement of the sleeve causing the key to be forced inward (e.g., by compression of a spring coupled to the key) and releasing it in response to the key being moved axially from a neutral position and being within a clearance threshold of a cavity of one of the first output disc and the second output disc.

[0061] The disclosure also provides support for a clutch engagement system of a transmission system, comprising: a sleeve that is axially movable, a first output disc in a first position, a second output disc in a second position, and a radially displaceable key extending from the sleeve and configured to individually engage each of the first output disc and the second output disc. In a first example of the system, the sleeve, the first output disc, and the second output disc are coaxial, and the second output disc circumferentially surrounds the sleeve, and the first output disc circumferentially surrounds both the second output disc and the sleeve.In a second example of the system, optionally including the first example, the sleeve is provided with a grooved portion and an end portion having two or more outer cavities and inner teeth arranged to mesh with a rotating element of the gear system. In a third example of the system, optionally including one or both of the first and second examples, each outer cavity is arranged equidistantly along an outer surface of the end portion of the sleeve, and each outer cavity contains one of two or more springs.

[0062] In a fourth example of the system, optionally comprising one or more or each of the first to third examples, each outer cavity comprises a first portion having a square or rectangular cross-section and a second portion having a circular cross-section, the first portion and the second portion being adjacent to each other. In a fifth example of the system, optionally comprising one or more or each of the first to fourth examples, the radially displaceable key is one of two or more keys, and each key comprises a key head and a key shank, and each spring is positioned within the second portion of each outer cavity and coupled to a key via the key shank.In a sixth example of the system, optionally comprising one or more or each of the first to fifth examples, a shape of the key head is a chamfered rectangular prism, the chamfered rectangular prism being a rectangular prism in which two parallel faces of the rectangular prism are chamfered, and in which each key head is disposed within the first portion of each outer cavity.

[0063] In a seventh example of the system, optionally comprising one or more or each of the first to sixth examples, each of the first output disc and the second output disc includes a plurality of internal cavities and an internal groove disposed on an internal surface on one side of the first output disc and the second output disc, and internal teeth disposed to mesh with a gear shaft on another side of the first output disc and the second output disc. In an eighth example of the system, optionally comprising one or more or each of the first to seventh examples, each internal cavity is disposed along the internal surface of the first output disc and the second output disc and is equidistantly spaced from another internal cavity by a portion of the internal surface of either the first output disc or the second output disc.In a ninth example of the system, optionally comprising one or more or each of the first to eighth examples, the first output disc is arranged to mesh with a carrier of a reduction gear, and the second output disc is arranged to mesh with a pinion of the reduction gear.

[0064] The disclosure also provides support for a method of operating a clutch, comprising receiving output signals from sensors indicating that a speed difference between a sleeve and a first output disc is within a speed difference threshold, wherein the speed of the first output disc and the sleeve are substantially the same, axially translating the sleeve of the clutch from a neutral position to a first position via an actuator, and rotating the sleeve in the first position to allow a wedge to impact and extend into an internal cavity of the first output disc. In a first example of the method, the key impacts the internal cavity when the key is positioned within a distance threshold from the internal cavity.In a second example of the method, optionally including the first example, the key extends into the internal cavity in response to a spring force generated by pushing in the key and is released.

[0065] In a third example of the method, optionally comprising one or both of the first and second examples, the method further comprises: axially translating the sleeve of the clutch from the first position to the neutral position, receiving output signals from sensors indicating that the speed difference between the sleeve and a second output disc is within a threshold, wherein the speed of the second output disc and the sleeve are nearly the same, axially translating the sleeve of the clutch from the neutral position to a second position via the actuator, and rotating the sleeve in the second position to allow the wedge to impact the internal cavity and extend into the internal cavity of the second output disc.In a fourth example of the method, optionally comprising one or more or each of the first to third examples, the sleeve is selectively coupled to neither the first output disc nor the second output disc, and the key extends into inner grooves of the first output disc and the second output disc and rotates in the inner grooves when the sleeve is in the neutral position.

[0066] The disclosure also provides support for an engagement system comprising: a clutch having a sleeve that is axially slidable and rotatable and provided with two or more keys, two or more springs, and internal teeth arranged to mesh with a rotating member, and having a first output disc in a first position and a second output disc in a second position that are rotatable and provided with internal teeth arranged to mesh with the rotating member, a plurality of internal cavities, and an internal groove, wherein the sleeve is selectively coupled to one of the first output disc or the second output disc by axially adjusting a position of the sleeve and inserting the two or more keys into one of the first output disc or the second output disc.In a first example of the system, the sleeve is selectively coupled to the first output disc in the first position by axially adjusting the position of the sleeve to be to the left of a neutral position, wherein the first position is to the left of the neutral position. In a second example of the system, optionally including the first example, the sleeve is selectively coupled to the second output disc in the first position by axially adjusting the position of the sleeve to the right of the neutral position, wherein the second position is to the right of the neutral position.In a third example of the system, optionally comprising one or both of the first and second examples, each spring, in response to being within a threshold distance of an internal cavity, compresses radially against a sleeve, the sleeve extending into an internal cavity of the first output disc or the second output disc to selectively connect the sleeve to the first output disc or the second output disc. In a fourth example of the system, optionally comprising one or more or each of the first to third examples, each key is released from each internal cavity and forced inwardly when the sleeve is axially translated and a beveled surface of the key presses against a side surface of the internal groove of the first output disc or the second output disc.

[0067] Fig.1-7 show example configurations with the relative arrangement of the various components. When these elements are in direct contact with each other or are directly coupled, they may be referred to as being in direct contact or directly coupled, respectively, at least in one example. Similarly, elements shown side by side or adjacent to each other may be adjacent to each other or adjacent to each other, at least in one example. For example, components that are in surface-to-surface contact with each other may be referred to as being in surface-to-surface contact. As another example, in at least one instance, elements that are separated from each other with only a space between them and that do not have any other components may be referred to as such.In yet another example, elements depicted above / below, on opposite sides, or to the left / right of each other may be referred to as such, relative to each other. Further, in at least one example, as depicted in the figures, a topmost element or point of an element may be referred to as a "top" of the component, and a bottommost element or point of the element may be referred to as a "bottom" of the component. As used herein, the terms top / bottom, upper / lower, above / below may refer to a vertical axis of the figures and may be used to describe the positioning of elements of the figures relative to each other. Thus, in one example, elements displayed above other elements are arranged vertically above the other elements.As another example, the shapes of the elements depicted in the figures may be referred to as such (e.g., circular, straight, flat, curved, rounded, beveled, angled, or the like). Furthermore, in at least one example, depicted elements that intersect each other may be referred to as intersecting elements or as intersecting elements. Furthermore, an element depicted inside another element or outside another element may be referred to as such.

[0068] It should be noted that the example control and estimation routines contained herein may be used with various powertrain and / or vehicle configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and executed by the control system, including the controller, in combination with the various sensors, actuators, and other system hardware. The specific routines described herein may represent any one or more processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Thus, the various actions, operations, and / or functions illustrated may be performed in the order illustrated, in parallel, or, in some cases, without them.Accordingly, the order of processing is not required to achieve the features and advantages of the exemplary embodiments described herein, but is provided for convenience of illustration and description only. One or more of the illustrated actions, operations, and / or functions may be performed repeatedly depending on the strategy used. Furthermore, the described actions, operations, and / or functions may graphically represent code to be programmed into a non-transitory memory of the computer-readable storage medium in the electric motor control system, wherein the described actions are performed by executing the instructions in a system in combination with the electronic controller.

[0069] It should be understood that the configurations and routines disclosed herein are exemplary in nature and that these specific embodiments should not be considered limiting, as numerous variations are possible. For example, the technology described above may be applied to various vehicle and powertrain configurations. Unless expressly stated otherwise, the terms "first," "second," "third," etc., are not intended to denote any order, position, quantity, or importance, but are used merely to distinguish the individual elements. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, as well as other features, functions, and / or characteristics disclosed herein.

[0070] The following claims particularly point out certain combinations and subcombinations that are considered novel and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims are to be construed as including the inclusion of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope than the original claims, are also to be considered included within the subject matter of the present disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 9,358,866, B2

[0003]

Claims

[1] Clutch engagement system of a transmission system, comprising: a sleeve (202) which is axially movable; a first output disc (212) in a first position; a second output disc (222) in a second position and a radially displaceable key (302) extending from the sleeve and adapted to individually engage each of the first output disc and the second output disc. [2] The clutch engagement system of claim 1, wherein the sleeve (202), the first output disc (212) and the second output disc (222) are coaxial, the second output disc circumferentially surrounds the sleeve, and the first output disc circumferentially surrounds both the second output disc and the sleeve. [3] A clutch engagement system according to any one of the preceding claims, wherein the sleeve is provided with a grooved part (312) and an end part (310) having two or more outer cavities (206) and inner teeth (204) arranged to mesh with a rotating element of the transmission system (106). [4] A clutch engagement system according to claim 3, wherein each outer cavity (616) is arranged equidistantly along an outer surface of the end portion (310) of the sleeve (202) and each outer cavity contains one of two or more springs (606). [5] A clutch engagement system according to claim 3 or 4, wherein each outer cavity (616) comprises a first portion (208) having a square or rectangular cross-section and a second portion (210) having a circular cross-section, the first portion and the second portion being adjacent to each other. [6] The clutch engagement system of claim 5, wherein the radially displaceable key (302) is one of two or more keys, each key comprising a key head (304) and a key shank (306), and each spring (214) is positioned within the second portion (210) of each outer cavity and coupled to a key via the key shank. [7] The clutch engagement system of claim 6, wherein a shape of the key head (304) is a chamfered rectangular prism, the chamfered rectangular prism being a rectangular prism in which two parallel faces of the rectangular prism are chamfered, and wherein each key head is disposed within the first portion (208) of each outer cavity. [8] A clutch engagement system according to any preceding claim, wherein each of the first output plate (212) and the second output plate (222) has a plurality of internal cavities (410) and an internal groove (412) disposed on an internal surface on one side of the first output plate and the second output plate, and internal teeth disposed to mesh with a transmission shaft on another side of the first output plate and the second output plate. [9] The clutch engagement system of claim 8, wherein each inner cavity (218A) is positioned along the inner surface of the first output plate (212) and the second output plate (214) and is equidistantly spaced from another inner cavity by a portion of the inner surface of either the first output plate or the second output plate. [10] A clutch engagement system according to any one of the preceding claims, wherein the first output disc (212) is arranged to mesh with a carrier of a reduction gear and the second output disc (222) is arranged to mesh with a pinion of the reduction gear.

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