WO2023059351A1

WO2023059351A1 - Park lock actuator with decoupled manual release

Info

Publication number: WO2023059351A1
Application number: PCT/US2021/059174
Authority: WO
Inventors: Xiao Jun WEI
Original assignee: Stoneridge Control Devices, Inc.
Priority date: 2021-10-06
Filing date: 2021-11-12
Publication date: 2023-04-13

Abstract

An actuator for a vehicle driveline component includes a motor, a housing, a gear train that is arranged in the housing and coupled to the motor, and an output shaft that is arranged in the housing and coupled to the gear train. The output shaft is configured to move between multiple positions in response to rotational drive from the motor via the gear train. The output shaft is configured to be operatively connected to the vehicle driveline component. The actuator further includes a manual release shaft that extends through the housing to expose a feature that is configured to cooperate with a tool. The manual release shaft has a decoupled position in which the manual release shaft is immobile during rotation of the output shaft and a coupled position in which the manual release shaft is operatively connected to the output shaft to rotate the output shaft in response to an input provided at the feature.

Description

PARK LOCK ACTUATOR WITH DECOUPLED MANUAL RELEASE

BACKGROUND

[0001] The disclosure relates to an actuator for use in a vehicle driveline, for example, a park lock actuator for use in locking a transmission and/or differential to prevent the vehicle from moving when parked.

[0002] Park lock actuators are two-position devices used to lock and unlock a vehicle driveline component. During vehicle operation, the park lock actuator is unlocked, permitting the driveline to impart rotational drive from a power source to the vehicle’s wheels. When the vehicle is parked and not operating, the park lock actuator either manually or automatically engages to lock the driveline component and prevent movement of the vehicle.

[0003] One type of park lock actuator is driven by an electric motor in response to a switch and/or controller. In the event of a loss of power or access to the input for operating the actuator, a manual release is provided on the actuator outside the vehicle so the vehicle can be towed. The manual release is coaxial with and rotates with the actuator’s output shaft during normal actuator use.

SUMMARY

[0004] In one exemplary embodiment, an actuator for a vehicle driveline component includes a motor, a housing, a gear train that is arranged in the housing and coupled to the motor, and an output shaft that is arranged in the housing and coupled to the gear train. The output shaft is configured to move between multiple positions in response to rotational drive from the motor via the gear train. The output shaft is configured to be operatively connected to the vehicle driveline component. The actuator further includes a manual release shaft that extends through the housing to expose a feature that is configured to cooperate with a tool. The manual release shaft has a decoupled position in which the manual release shaft is immobile during rotation of the output shaft and a coupled position in which the manual release shaft is operatively connected to the output shaft to rotate the output shaft in response to an input provided at the feature. [0005] In a further embodiment of any of the above, the actuator includes a seal that surrounds the manual release shaft and engages the housing.

[0006] In a further embodiment of any of the above, the motor has a pinion, and the gear train includes multiple gear reduction sets. The gear train and the motor are back-drivable in response to the input at the feature.

[0007] In a further embodiment of any of the above, the gear train includes a sector gear that is coupled to the output shaft. The sector gear is coupled to the pinion via the multiple gear reduction sets.

[0008] In a further embodiment of any of the above, the actuator includes a release gear that is normally coupled to the output shaft for rotation therewith. The manual release shaft is configured to selectively engage with the release gear between the decoupled and coupled position.

[0009] In a further embodiment of any of the above, the release gear and the output shaft are coaxial with one another. The manual release shaft is rotatable about an axis parallel to the output shaft.

[0010] In a further embodiment of any of the above, the manual release shaft includes teeth that are configured to engage the release gear in the coupled position, and an untoothed region is adjacent the release gear in the decoupled position and with the teeth in non-engagement with the release gear.

[0011] In a further embodiment of any of the above, the actuator includes a plate that is arranged in the housing. The plate supports the output shaft, the manual release shaft and the gear train. The motor is mounted to the plate and arranged within the housing.

[0012] In a further embodiment of any of the above, the plate includes an arcuate slot. The manual release shaft includes a tab that is received in the slot and configured to limit rotation of the manual release shaft to less than 120°.

[0013] In a further embodiment of any of the above, the actuator includes a printed circuit board that is arranged in the housing and includes a sensor. The release gear supports a magnet that is aligned with the sensor. The sensor is configured to detect the multiple positions of the output shaft. [0014] In another exemplary embodiment, a vehicle driveline including the actuator includes a driveline component and a lock assembly. The output shaft is configured to move the lock assembly from locked and unlocked positions. The unlocked position is coincident with the uncoupled position.

[0015] In a further embodiment of any of the above, the lock assembly includes a locking gear and a parking pawl.

[0016] In a further embodiment of any of the above, the driveline component is a transmission.

[0017] In another exemplary embodiment, a method of manually releasing an actuator in a vehicle driveline includes initially rotating a manual release shaft from an operatively decoupled position that is relative to an output shaft to an operatively coupled position relative to the output shaft. The driveline further includes subsequently rotating the manual release shaft from the coupled position to rotationally drive an output shaft to a desired position.

[0018] In a further embodiment of any of the above, the method includes the step of energizing an electric motor to move the output shaft between first and second positions. The second position corresponds to the desired position. The initially rotating and subsequent rotating steps occur with the electric motor deenergized.

[0019] In a further embodiment of any of the above, the method includes the step of removably engaging the manual release shaft with a tool. The initially rotating and subsequent rotating steps are performed in response to rotation of the tool.

[0020] In a further embodiment of any of the above, a seal is provided between the manual release shaft and a housing that supports the manual release shaft. The manual release shaft is normally immobile relative to the seal during the energizing step.

[0021] In a further embodiment of any of the above, the manual release shaft and the output shaft are rotatable about different axes.

[0022] In a further embodiment of any of the above, the energizing step includes rotationally driving the output shaft via a gear train. The subsequently rotating step includes back-driving the electric motor via the gear train. [0023] In a further embodiment of any of the above, the first position is a park-lock position, and the second position is an unlocked position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The disclosure can be further understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0025] Figure 1A is a schematic view of a vehicle drive train including the disclosed actuator.

[0026] Figure 1 B is a schematic view of one type of park lock device.

[0027] Figure 2 is a perspective view of the disclosed actuator mounted to a driveline component and a tool used to manually release the park lock device through the actuator.

[0028] Figure 3 is a cross-sectional view of the assembly shown in Figure 2 taken along lines 3-3.

[0029] Figure 4 is a perspective view of the actuator shown in Figure 3 with the housing and other components illustrated in phantom to better illustrate an actuator gear train.

[0030] Figure 5 is the park lock actuator shown in cross-section through a portion of the gear train, including an output shaft used to operate the park lock device.

[0031] Figure 6A is an exploded view of a plate used to support the gear train, a manual release shaft and a motor.

[0032] Figures 6B and 6C are exploded views of first and second gear assemblies of the gear train.

[0033] Figure 6D is an exploded view of a printed circuit board and a portion of the gear train.

[0034] Figures 7A and 7B illustrate the actuator in an park-lock position preventing the vehicle from driving.

[0035] Figures 8A and 8B illustrate the actuator moving from an operatively decoupled position relative to an output shaft to an operatively coupled position relative to the output shaft. [0036] Figures 9A and 9B illustrate the manual release shaft having moved the output shaft to a desired, unlocked position.

[0037] The embodiments, examples and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible. Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0038] Figure 1 A illustrates a drive train 10 having a driveline component 12 such as a transmission or differential. The driveline component imparts drive from the vehicle’s propulsion system to the wheels. One type of drive train 10 includes a lock assembly 14 that moves between locked and unlocked positions to permit rotation of the driveline component during vehicle operation and lock out any rotation when the vehicle is parked to prevent the vehicle from rolling. The lock assembly 14 is operated by an actuator 16 that receives an electrical signal from a controller 18 and/or an input 20 such as a switch. Although the disclosed actuator is described as being used in a 2-position park-lock system, it should be understood that the actuator may have other applications and operate in more than two positions for those applications.

[0039] Referring to Figure 1 B, an example lock assembly 14 is shown. However, it should be understood that the illustrated lock assembly 14 is highly schematic and may be configured differently than shown. In the example, the driveline component 12 includes a locking gear 24 mounted to a component, such as a transmission output shaft. The locking gear 24 includes circumferentially spaced apart teeth 30 forming circumferentially spaced apart notches 32. A parking pawl 26 is movable about a pivot 28 to selectively cooperate with the notches 32. A spring 27 is shown illustrated between a transmission housing 21 and the parking pawl 26 to bias the pawl 26 to a normally unlocked position. An output shaft 22 from the actuator 16 rotationally drives a cam 34 that cooperates with the pawl 26 to move the pawl to a locked position in which its claw is seated within the notch 32, preventing rotation of the locking gear 24 and thus the driveline component 12.

[0040] Referring to Figure 2, the actuator 16 includes a manual release shaft 38 that is accessible through a housing 36 of the actuator 16. The manual release shaft 38 includes a feature 40, such as a hex socket, that receives a tool 42 such as wrench with a hexagonal end, for manual operation of the actuator 16 in the event there is no power to the actuator 16 or the actuator is otherwise not operational. Rotation of the manual release shaft 38 with the tool 42 rotates the output shaft 22 to unlock the locking assembly 14. Access to the feature 40 may be obstructed by a nearby component 44. The design of the disclosed actuator release affords some flexibility in locating the feature 40, enabling improved accessibility with the tool.

[0041] Referring to Figures 3-5, the housing 36 includes first and second housing portions 48, 50 secured to one another to provide a sealed cavity 72. A gear train 54 is supported by a plate 52 arranged within the cavity 72. A printed circuit board 56 may be mounted to the plate 52 and is used to monitor the actuator’s position and otherwise control the operation of the actuator 16. Typically, grease is arranged within the cavity 72 to lubricate the gear train 54 during operation. Since the actuator 16 is exposed to the harsh environmental elements outside the vehicle, it is important to prevent water and debris from entering the cavity 72. Thus, a seal 46 is provided between the manual release shaft 38 and the housing 36 (i.e., circumscribes or surrounds the shaft). Unlike prior art actuators, the manual release shaft 38 does not rotate with the output shaft 22 during normal operation, or is “decoupled” from the output shaft 22, which dramatically improves the longevity of the seal 46 such that the cavity 72 remains sealed during the life of the actuator 16.

[0042] Referring to Figures 4 and 5, a motor 58 having a pinion 60 is arranged within the housing 36. A first reduction gear set (Figure 6C) includes a first driven gear 82 in engagement with the pinion 60. A first drive gear 84 cooperates with a second driven gear 86 of a second reduction gear set (Figure 6B). A second drive gear 88 engages a sector gear 98 that is coupled to the output shaft 22.

[0043] As shown in Figure 4, the manual release shaft 38 includes teeth 120 that are selectively coupled to a release gear 104 affixed to the output shaft 22 and sector gear 98. In the example arrangement, the motor 58 and the pinion 60 are rotatable about a first axis 62, the first reduction gear set is rotatable about a second axis 64, the second reduction gear set is rotatable about a third axis 66, the output shaft with its sector gear 98 and release gear 104 is rotatable about a fourth axis 68, and the manual release shaft 38 is rotatable about a fifth axis 70. In the example, all five axes are spaced apart from and parallel to one another. The arrangement provides a back-drivable gear train and motor arrangement to enable movement of the output shaft 22 in response to rotation from the manual release shaft 38.

[0044] Referring to Figure 6A, the plate 52 supports the motor 58 via fasteners. The manual release gear 38 includes a recess 1 14 (Figure 5) located with respect to a protrusion 116 on the plate. A fastener 118 secures the manual release shaft 38 to the plate 52 while still permitting rotation.

[0045] The plate 52 includes an arcuate slot 122 that receives a tab 124. The manual release shaft 38 includes teeth 120 and an untoothed region 126. This arrangement allows the release gear 104 to freely rotate during normal actuator use when the untoothed region 126 is adjacent to the release gear 104 (Figure 5). In the example, slot 122 and tab 124 arrangement limit rotation of the manual release shaft 38 to less than 120°.

[0046] Referring to Figures 6B and 6C, the first gear reduction set is mounted to a first shaft 92 supported by first bearings 90 received by the plate 52 and housing 36. Similarly, the second gear reduction set includes a second shaft 96 mounted to second bearings 94 received in the plate 52 and housing 36.

[0047] Referring to Figure 6D, the sector gear 98 is supported by a bushing 100 mounted to the housing 36. The output shaft 22 is affixed to the sector gear 98, as shown in Figure 3. The sector gear 98 includes a key way 102 for receiving a key 106 ensuring the sector gear 98 and release gear 104 rotate with one another about the fourth axis 68.

[0048] The release gear 104 includes a pocket 108 receiving a magnet 110. The magnet 110 is arranged adjacent to a sensor 112 on the circuit board 56. The sensor 112 monitors the rotational position of the sector gear 98, and thus the actuator between its locked and unlocked positions based upon the orientation of the magnet 110 with respect to the sensor 1 12, best shown in Figure 3.

[0049] Referring to Figures 7A and 7B, the manual release gear 38 is shown oriented in a normal operating position in which the untoothed region 126 (e.g., at least 180° of the periphery) is aligned with the release gear 104 such that the sector gear 98 and its attachment output shaft 22 can freely move between the locked and unlocked positions in response to operation of the motor 58 during normal operation. In the event of a power failure or other malfunction that prevents normal operation of the actuator 16, a tool cooperates with the manual release shaft 38 to move the teeth 120 into engagement with the release gear 104 as shown in Figures 8A-8B. The output shaft 22 is configured to move the lock assembly 14 between the locked and unlocked positions, where the unlocked position is coincident with the uncoupled position. Further rotation of the manual release shaft 38 causes the teeth 120 to cooperate with the release gear 104 and rotate the normally coupled output shaft 38 thus unlocking the lock assembly 14. During rotation, the gear train 54 along with the motor 58 is back driven.

[0050] During normal use, the actuator 16 is operated by energizing the electric motor 58 to move the output shaft 22 via the gear train 54 between first and second positions (e.g., park-locked and unlocked). However, the manual release shaft 38 is immobile during rotation of the output shaft 22. To manually release the actuator 16, the tool 42 is inserted into the feature 40 and turned so that the manual release shaft 38 is initially rotated from an operatively decoupled position relative to the output shaft 22 to an operatively coupled position relative to the output shaft 22 in which the teeth 120 begin to mesh with the release gear 104. As the tool 42 continues to rotate the feature 40, the manual release shaft 38 subsequently rotates from the coupled position to rotationally drive the output shaft 22 to unlock the lock assembly 22.

[0051] It should also be understood that although a particular component arrangement is disclosed in the illustrated embodiment, other arrangements will benefit herefrom. Although particular step sequences are shown, described, and claimed, it should be understood that steps may be performed in any order, separated or combined unless otherwise indicated and will still benefit from the present invention. [0052] Although the different examples have specific components shown in the illustrations, embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples.

[0053] Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.

Claims

CLAIMS What is claimed is:

1 . An actuator for a vehicle driveline component, comprising: a motor; a housing; a gear train arranged in the housing and coupled to the motor; an output shaft arranged in the housing and coupled to the gear train, the output shaft configured to move between multiple positions in response to rotational drive from the motor via the gear train, the output shaft configured to be operatively connected to the vehicle driveline component; and a manual release shaft extending through the housing to expose a feature configured to cooperate with a tool, the manual release shaft having a decoupled position in which the manual release shaft is immobile during rotation of the output shaft and a coupled position in which the manual release shaft is operatively connected to the output shaft to rotate the output shaft in response to an input provided at the feature.

2. The actuator of claim 1 , comprising a seal surrounding the manual release shaft and engaging the housing.

3. The actuator of claim 1 , wherein the motor has a pinion, and the gear train includes multiple gear reduction sets, the gear train and the motor are back- drivable in response to the input at the feature.

4. The actuator of claim 3, wherein the gear train includes a sector gear coupled to the output shaft, the sector gear coupled to the pinion via the multiple gear reduction sets.

5. The actuator of claim 1 , comprising a release gear that is normally coupled to the output shaft for rotation therewith, the manual release shaft is configured to selectively engage with the release gear between the decoupled and coupled position.

6. The actuator of claim 5, wherein the release gear and the output shaft are coaxial with one another, and the manual release shaft is rotatable about an axis parallel to the output shaft.

7. The actuator of claim 6, wherein the manual release shaft includes teeth configured to engage the release gear in the coupled position, and an untoothed region adjacent the release gear in the decoupled position and with the teeth in nonengagement with the release gear.

8. The actuator of claim 7, comprising a plate arranged in the housing, the plate supporting the output shaft, the manual release shaft and the gear train, wherein the motor is mounted to the plate and arranged within the housing.

9. The actuator of claim 8, wherein the plate includes an arcuate slot, and the manual release shaft includes a tab received in the slot and configured to limit rotation of the manual release shaft to less than 120°.

10. The actuator of claim 5, comprising a printed circuit board arranged in the housing and including a sensor, the release gear supporting a magnet that is aligned with the sensor, the sensor is configured to detect the multiple positions of the output shaft.

11. A vehicle driveline including the actuator of claim 1 , comprising: a driveline component; and a lock assembly, the output shaft configured to move the lock assembly from locked and unlocked positions, and the unlocked position coincident with the uncoupled position.

12. The driveline of claim 11 , wherein the lock assembly includes a locking gear and a parking pawl.

13. The driveline of claim 11 , wherein the driveline component is a transmission.

14. A method of manually releasing an actuator in a vehicle driveline, comprising: initially rotating a manual release shaft from an operatively decoupled position relative to an output shaft to an operatively coupled position relative to the output shaft; and subsequently rotating the manual release shaft from the coupled position to a rotationally drive an output shaft to a desired position.

15. The method of claim 14, comprising the step of energizing an electric motor to move the output shaft between first and second positions, the second position corresponding to the desired position, wherein the initially rotating and subsequent rotating steps occur with the electric motor deenergized.

16. The method of claim 15, comprising the step of removably engaging the manual release shaft with a tool, wherein the initially rotating and subsequent rotating steps are performed in response to rotation of the tool.

17. The method of claim 15, wherein a seal is provided between the manual release shaft and a housing supporting the manual release shaft, wherein the manual release shaft is normally immobile relative to the seal during the energizing step.

18. The method of claim 17, wherein the manual release shaft and the output shaft are rotatable about different axes.

19. The method of claim 18, wherein the energizing step includes rotationally driving the output shaft via a gear train, and the subsequently rotating step includes back-driving the electric motor via the gear train.

20. The method of claim 15, wherein the first position is a park-lock position, and the second position is an unlocked position.