Cam Clutch Load-Supported Cam Tilting for Stable Mode Switching
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Solution Overview
Problem
Existing two-way clutches experience poor responsiveness due to time lost when switching rotation direction and variations in cam position and attitude, leading to inconsistent operation timing.
Innovation Solution
A cam clutch design featuring an inner and outer race with biased cams, where an operating mode switch mechanism independently tilts the cams with a load support point radially between the load application and contact points, ensuring consistent cam positioning and attitude, thus improving stability and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sprags are tilted in the same direction as rotation direction to switch engagement states, then the clutch can transmit and interrupt rotary force, but responsiveness deteriorates due to time lost when rotation direction is switched
Solution Approach 1:
Instead of tilting cams in the direction of rotation like conventional sprags, this invention tilts the cams in the opposite direction (radially outward when rotated in the direction opposite to rotation). This inversion allows the cam clutch to achieve both reliable engagement and rapid switching response, eliminating the time loss problem of conventional designs.
Solution Approach 2:
The cam mechanism dynamically switches between engagement and disengagement states by rotating the cam clutch body. The cams are biased by spring means and can be forcibly tilted by rotation, enabling the clutch to quickly transition between locked and free states without the time delay inherent in conventional sprag designs.
2Device complexity
If multiple cams are circumferentially equally spaced in retainer pockets, then the clutch structure is simplified, but cam position and attitude variations occur leading to inconsistent operation timing
Solution Approach 1:
The cam clutch body includes asymmetric cam attitude change parts positioned at specific locations to tilt the cams. This asymmetric design compensates for the natural variations in cam positioning that occur when cams are placed in retainer pockets, ensuring consistent cam attitude and operation timing while maintaining the simple circumferential spacing arrangement.
Solution Approach 2:
The cam attitude change parts act as intermediaries between the cam rotation and the inner/outer races. These parts forcibly tilt the cams to a predetermined attitude, mediating the position variations that occur in the retainer pockets and ensuring consistent operational timing across all cams.
3Productivity
If the radial distance between load application point and load support point is increased, then a larger moment acts on cams improving attitude change efficiency, but the structural compactness is reduced
Solution Approach 1:
The cam attitude change parts utilize the axial dimension in addition to the radial dimension to achieve the desired moment on the cams. By positioning the load application point axially offset from the cam center, the design achieves a larger effective moment arm without significantly increasing the radial volume of the clutch components.
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
The design restricts cam position and attitude variations, allowing for efficient switching among four operating modes with improved stability and responsiveness, achieved without increasing component count or complexity.
Implementation Method 1
a biasing means biasing each of the plurality of cams so that each of the plurality of cams makes contact with the inner race and the outer race
Implementation Method 2
a load support point is located radially between a load application point of the cam attitude change part on the cam and a distal contact point of the cam on a raceway, a radial distance between the load application point and the load support point being larger than a radial distance between the load support point and the distal contact point
Data Source
AI summary
An object of the present invention is to provide a cam clutch capable of switching from one operating mode to another and offering improved stability of clutch operations and high responsiveness. The object is achieved by an operating mode switching means (180) having a cam attitude change part (185) being drivable independently of rotation of the inner race (110) and outer race (120). A load support point (Sp) is located radially between a load application point (Ap) of the cam attitude change part (185) on the cam (140) and a distal contact point (Ep) of the cam (140) on a raceway positioned on a radially distal side relative to the load application point (Ap). The radial distance (d1) between the load application point (Ap) and the load support point (Sp) is larger than the radial distance (d2) between the load support point (Sp) and the distal contact point (Ep).