Ratchet Lever Segmentation for Driving Force Distribution Responsiveness
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Solution Overview
Problem
Existing driving force distribution devices require a large rotational angle of the rotary drive member to disengage the ratchet from the ratchet groove, necessitating excessive rotational input from the actuator, which affects the responsiveness of the sub transmission and clutch pressing force.
Innovation Solution
The driving force distribution device incorporates a ratchet lever with a drive pawl and arm to rotate the shift cam and friction clutch driving cam, allowing the ratchet lever to disengage from the shift cam when rotated one way and engage when rotated the opposite way, along with a shutter member to prevent re-engagement, reducing the required rotational angle and improving responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ratchet is moved along the ratchet groove to disengage from the groove, then the sub transmission can be shifted and clutch pressing force can be adjusted, but a large circumferential rotation angle is required which slows down the response
Solution Approach 1:
The ratchet lever is divided into a drive pawl portion and an arm portion that can rotate relative to each other. The drive pawl engages with the ratchet groove for reliable shifting, while the arm portion can rotate independently to disengage the drive pawl from the groove, enabling rapid response without requiring large rotational movement of the entire ratchet lever along the groove.
Solution Approach 2:
Instead of moving the entire ratchet lever along the ratchet groove to disengage (conventional approach), the invention rotates the arm portion in the opposite direction to swing the drive pawl away from the groove. This inverted approach reduces the required rotation angle from a large circumferential movement to a small angular rotation of the arm portion.
2Productivity
If a sliding ratchet is used on the rotary drive member, then the sub transmission can be alternately switched between high and low speeds, but the ratchet must be moved along a long ratchet groove which requires excessive rotational input
Solution Approach 1:
The ratchet lever is segmented into a drive pawl that engages the ratchet groove for shifting and an arm that rotates independently to control disengagement. This segmentation allows the drive pawl to remain engaged for rapid alternating shifts while the arm rotates minimally to disengage when needed, reducing the actuator rotation input required.
Solution Approach 2:
The invention changes the disengagement mechanism from linear movement along the ratchet groove to rotational movement of the arm portion. This dimensional change from one-dimensional linear displacement to two-dimensional rotational articulation reduces the total movement required and allows quicker disengagement with less actuator rotation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the rotational angle needed for ratchet disengagement, enhancing the responsiveness of the sub transmission and clutch pressing force, allowing for quicker shifts and preventing sudden shifts during vehicle operation.
Implementation Method 1
a ratchet lever provided so that a shaft line thereof in a normal direction with respect to the outer surface of the rotary drive member is a rotation center, wherein the ratchet lever is disengaged from the shift cam and is rotated when the rotary drive member is rotationally driven to one side from a predetermined position starting at control origin of the shift cam, and the ratchet lever is rotated in conjunction with the shift cam when the rotary drive member is rotationally driven in a direction opposite to the one side
Implementation Method 2
the ratchet lever comprises a drive pawl for rotating the shift cam by engaging with a ratchet groove formed on the shift cam
Implementation Method 3
an arm integrally formed with the drive pawl, the arm contacting with a drive pin provided on the friction clutch driving cam to rotate and retract the drive pawl to a released position where the drive pawl does not engage with the ratchet groove
Implementation Method 4
a shutter member for preventing engagement between the drive pawl and the ratchet groove by lying therebetween when the drive pawl is rotated and retracted to a released position not engaging with the ratchet groove
Data Source
AI summary
A driving force distribution device includes a sub transmission, a friction clutch, a rotary drive member fixed to an output shaft of an actuator, a friction clutch driving cam to change a pressing force of the friction clutch, a shift cam to shift the sub transmission by converting rotary motion of the actuator into linear motion, and a ratchet lever provided so that a shaft line thereof in a normal direction with respect to the outer surface of the rotary drive member is a rotation center. The ratchet lever is disengaged from the shift cam and is rotated when the rotary drive member is rotationally driven to one side from a predetermined position starting at control origin of the shift cam, and the ratchet lever is rotated in conjunction with the shift cam when the rotary drive member is rotationally driven in a direction opposite to the one side.