Tractor Clutch Control for Smooth Launching
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Solution Overview
Problem
The existing braking controlling apparatus in tractors experiences delayed launching due to poor response of the oil hydraulic multiple disc clutch when the brake pedals are stepped on, leading to bothersome clutch and brake manipulation during frequent stopping and starting.
Innovation Solution
A tractor with a control unit that detects brake pedal manipulation using sensors, allowing the forward/backward movement clutch to maintain a low operating pressure when the brakes are applied, ensuring smooth launching by preventing the clutch from being completely off, and restoring pressure when the brakes are released, with higher pressure raising rates at higher speed positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch joining pressure is allowed to be zero during brake application, then the clutch can be completely disengaged for stopping, but the clutch joining response becomes poor and launching is delayed
Solution Approach 1:
The control unit maintains the clutch in a preliminarily engaged state by preventing complete disengagement during brake application. The clutch pressure is reduced to a low level rather than zero, keeping the clutch ready for quick re-engagement. This preliminary preparation ensures that when the brake is released, the clutch can immediately resume power transmission without the delay of re-establishing engagement from a completely disengaged state.
Solution Approach 2:
The system dynamically adjusts the clutch pressure based on brake application status. During braking, the clutch pressure is dynamically reduced to a low level (not zero) rather than being completely disengaged. This dynamic pressure modulation allows the clutch to remain in a semi-engaged state that facilitates quick response when braking is released, resolving the contradiction between reliable stopping and fast launching.
2Ease of operation
If the clutch is allowed to be automatically off during brake manipulation, then frequent stopping and starting becomes easier, but the launching is delayed due to poor clutch response
Solution Approach 1:
The control unit performs preliminary action by maintaining the clutch in a ready-to-engage state during brake application. Instead of allowing complete disengagement, the system keeps the clutch pressure at a low level, preliminarily preparing the clutch for immediate re-engagement. This eliminates the time loss associated with clutch re-engagement while preserving the ease of automatic control during frequent stopping and starting operations.
Solution Approach 2:
The clutch maintains a continuous low-level engagement during brake application rather than completely disengaging. This continuity of useful action ensures that the clutch remains prepared for power transmission throughout the braking period, eliminating interruptions in the clutch's readiness to transmit power. When braking is released, the clutch can immediately resume full power transmission without interruption or delay.
3Reliability
If the clutch pressure is completely released during stopping, then the clutch can be fully disengaged, but the joining response is bad and smooth launching cannot be achieved
Solution Approach 1:
The control unit applies preliminary action by maintaining the clutch in a semi-engaged state during stopping. The clutch pressure is reduced to a low level rather than completely released, keeping the clutch preliminarily prepared for quick re-engagement. This preliminary maintenance of engagement ensures smooth launching is achieved while preserving reliable stopping function.
Solution Approach 2:
The system dynamically controls clutch pressure to maintain it at a low non-zero level during brake application. This dynamic pressure control allows the clutch to remain in a flexible semi-engaged state that supports both reliable stopping and smooth launching. The clutch can smoothly transition from this semi-engaged state to full engagement when braking is released, achieving smooth launching while maintaining stopping reliability.
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 solution enables smooth and prompt launching from a stopping state and faster attainment of target speeds by maintaining a low pressure on the clutch during stopping and restoring pressure efficiently when the brakes are released, improving the overall braking and acceleration performance.
Implementation Method 1
the motive power transmission clutch (48) is an oil hydraulic multiple disc clutch
Implementation Method 2
a plurality of sensors (123L, 123R) for detecting a manipulation state of the brake pedals (19L, 19R)
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A tractor, including: an engine (5); a forward/backward movement clutch (48) which is provided on a motive power transmission route from the engine (5) to one or more traveling apparatuses (3), and is configured to carry out changes among forward movement, backward movement and neutral; one or more brake pedals (19L,19R); and a control unit (120) which is configured to allow, in association with stepping manipulation of the one or more brake pedals (19L, 19R), one or more brakes (135) to operate on the one or more traveling apparatuses (3) and allow operating-pressure of the forward/backward movement clutch (48) to lower.