Backpack Power Transmission With One-Way Clutch for Torsional Vibration
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Solution Overview
Problem
Conventional backpack power working machines, such as brush cutters, experience torsional vibration in the operating rod due to torque fluctuations from internal combustion engines, which are exacerbated by lean-burn conditions, and existing solutions for suppressing this vibration either compromise operability or durability or increase weight and cost.
Innovation Solution
A one-way clutch assembly is integrated into the rotation transmission mechanism between the flexible shaft and drive shaft, supported by a ball bearing within a pipe coupling, to prevent torsional vibration and maintain smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-way clutch is assembled into the clutch drum of the internal combustion engine to suppress torsional vibration, then the torsional vibration in the operating rod is reduced, but the projection amount of the connecting portion increases, reducing operability
Solution Approach 1:
The one-way clutch is extracted from the clutch drum and relocated to the drive shaft. This separation allows the clutch drum to maintain its original compact dimensions while the one-way clutch functions independently on the drive shaft, eliminating the projection issue while preserving vibration suppression capability
Solution Approach 2:
A coupling mechanism is introduced as an intermediary component between the clutch drum and the drive shaft. This coupling allows the one-way clutch to be positioned on the drive shaft while maintaining functional connection to the clutch drum, resolving the spatial conflict between vibration suppression and operability
2Ease of operation
If the drive source is located separately from the backpack mount to ensure rotational range, then the rotational range is sufficient, but the operator feels an increase in weight
Solution Approach 1:
The drive source is merged with the backpack mount by positioning the one-way clutch and coupling mechanism within the existing structural space of the backpack mount assembly. This integration allows the drive source to function with adequate rotational range while being carried on the operator's back, avoiding the need for separate positioning that would increase perceived weight
3Reliability
If a special connecting structure is used to assemble the one-way clutch into the clutch drum, then the one-way clutch can be integrated, but customization of engine components is required, increasing cost and inhibiting component sharing
Solution Approach 1:
The one-way clutch and coupling mechanism are designed as universal components that can be applied across different engine models without customization. The coupling mechanism serves multiple functions: connecting the clutch drum to the drive shaft, accommodating the one-way clutch, and allowing for easy assembly and disassembly. This universal design enables component sharing across product lines while maintaining effective one-way clutch integration
Solution Approach 2:
The connection structure is segmented into separate, standardized components rather than requiring custom-integrated engine modifications. The coupling mechanism is a distinct component that interfaces with standard engine mounting points, allowing the one-way clutch system to be assembled from modular parts without customizing the engine block or clutch drum itself
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 solution effectively suppresses torsional vibration in the operating rod, improving durability and operability while reducing weight and cost, allowing comfortable operation for the user.
Implementation Method 1
a one-way clutch is disposed in a transmission system from a clutch drum to a rotary blade shaft (a rotating shaft of a cutting edge) so as to transmit the rotation only in a normal rotational direction with respect to the rotational direction of the drive shaft
Implementation Method 2
a ball bearing (98) is interposed between the shaft coupling (80) and the pipe coupling (88) and supports an intermediate portion of the coupling body (82) inside of the pipe coupling (88)
Implementation Method 3
An output shaft of the internal combustion engine connects to an operating rod provided with, for example, a grip, an on-off switch, a throttle lever, a handle for moving a cutting blade operating unit from side to side, and the like, via a flexible shaft covered with a flexible tube
Data Source
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AI summary
Provided is a backpack power working machine with which an operator performs operation while carrying on his/her back a backpack mount with a drive source mounted thereon. The backpack power working machine is capable of effectively suppressing torsional vibration in an operating rod generated in adjusting speed. A one-way clutch (87) for preventing generation of torsional vibration in an operating rod (6) is interposed between a coupling body (82) and a drive shaft (60). A ball bearing (98) that supports an intermediate portion of the coupling body (82) inside of a pipe coupling (88) is interposed between a shaft coupling (80) and the pipe coupling (88).