A car automatic transmission with seamless gear shifting

Abstract

The invention discloses a seamless gear shifting automobile automatic transmission. The seamless gear shifting automobile automatic transmission comprises an input shaft, an output shaft and a gear shifting mechanism, wherein the gear shifting mechanism comprises a gear shifting motor and a gear shifting drum; a shifting fork, a transmission gear and a three-position bidirectional controllable overrunning clutch are arranged in each gear; the overrunning clutch is meshed with the transmission gear; the overrunning clutch and the transmission gear are respectively arranged on the input shaft or the output shaft. During gear shifting, the gear shifting motor drives the gear shifting drum to rotate, when the gear shifting drum rotates for one preset angle, the overrunning clutch in a corresponding gear is switched among an idle state, a forward driving reversed overrunning state and a reversed driving forward overrunning state, a three-position bidirectional controllable overrunning clutch is arranged in each gear, an object gear enters a driving state firstly and then a current gear enters the idle state during gear shifting, a clutch coupled with an engine is not required to be started during gear shifting, and mechanical seamless gear shifting is realized.

Description

Technical field [0001] The invention relates to the technical field of automobile gearboxes, in particular to an automobile automatic gearbox with seamless shifting. Background technique [0002] In order to improve handling and comfort, most internal combustion engine cars use automatic transmissions. At present, most cars on the market use the following three mainstream transmissions: 1. A T automatic transmission with hydraulic torque conversion and planetary gears. 2. Dual-clutch gearbox. 3. Cone wheel stepless gearbox. The three automatic transmissions have their own advantages and disadvantages, as follows: [0003] (1). AT automatic gearbox adopts flexible coupling rather than rigid transmission between the torque converter and the gearbox, which improves the starting comfort but reduces the transmission efficiency, so this kind of gearbox has acceleration performance In order to reduce the overall fuel consumption and the smoothness of shifting, it is often necessary to ...

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Problems solved by technology

But these advantages have also created some insurmountable shortcomings. When driving at low speeds, such as stop-and-go traffic jams, due to the low transmission ratio of the low-speed gear, the transmission force and resistance of the engine have a greater impact on the body. The throttle causes the body to stumble. In order to solve this problem, some manufacturers will advance the timing of shifting from 1st gear to 2nd gear, that is, to switch from 1st gear to 2nd gear in advance. The control program of the transmission keeps the clutch in a half-clutch state. Long-term half-clutching leads to rapid wear and heat of the clutch, which easily causes low-speed instability of this gearbox. The stroke is very short (as mentioned earlier, the shifting speed of this gearbox is very fast and the stroke is very short due to structural limitations), which also results in low starting comfort and prone to jittering

In terms of manufacturing complexity and cost, it is slightly lower than AT automatic transmission, and the control logic is also relatively complicated

[0005] (3). The advantage of the cone-wheel CVT is that it has no actual physical gear, so there is no shift gap, and it is very smooth during the entire acceleration process. Logically, it is the best transmission method, but due to Its transmission is generated by the friction between the chain belt and the cone wheel, which also has high requirements for the matching accuracy, material and wear resistance of the chain belt and the cone wheel. The transmission torque should not be too large, and the actual application It is prone to slipping phenomenon, not suitable for rapid acceleration and deceleration

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