Transmission structure

Patent metadata

Field	Value
Publication number	US-2023014393-A1
Application number	US-202217867641-A
Country	US
Kind code	A1
Filing date	Jul 18, 2022
Priority date	Jul 19, 2021
Publication date	Jan 19, 2023
Grant date	—

Abstract

A transmission structure of the present invention causes, during a period from a time point when a rotational speed of a drive rotational power reaches a predetermined first/second speed stage shift-up start speed until a first/second speed stage shift-up end time point, one of an input-side clutch mechanism pair and an output-side clutch mechanism pair to be in a double transmitting state, and causes, in the double transmitting state, a first clutch mechanism and a second clutch mechanism of the other one of the input-side clutch mechanism pair and the output-side clutch mechanism pair to be shifted to a disengagement sate and an engagement state, respectively, while having frictional plate slid.

First claim

1 . A transmission structure continuously changing a rotational speed of a rotational power that is operatively transmitted from a drive source and outputting a rotational power whose rotational speed has been changed toward a driving wheel, the transmission structure comprising:
an HST that continuously changes the rotational speed of the rotational power operatively transmitted from the drive source to a rotational speed including a range of at least between a first HST speed and a second HST speed in accordance with an operating position of an output adjusting member and that outputs a rotational power whose rotational speed has been changed; an HST speed change actuator that actuates the output adjusting member; a planetary gear mechanism that includes first to third elements and that is configured so that the third element acts as an input portion inputting the rotational power that the HST outputs; an input-side first transmission mechanism capable of operatively transmitting the rotational power, which operatively receives from the drive source, to the first element at an input-side first speed change ratio; an input-side second transmission mechanism capable of operatively transmitting the rotational power, which operatively receives from the drive source, to the second element at an input-side second speed change ratio; an input-side clutch mechanism pair including input-side first and second clutch mechanisms of a frictional plate type that engage and disengage the power transmissions of the input-side first and second transmission mechanisms, respectively; a speed change output shaft; an output-side first transmission mechanism capable of operatively transmitting the rotational power, which operatively receives from the second element, to the speed change output shaft at an output-side first speed change ratio; an output-side second transmission mechanism capable of operatively transmitting the rotational power, which operatively receives from the first element, to the speed change output shaft at an output-side second speed change ratio; an output-side clutch mechanism pair including output-side first and second clutch mechanisms that engage and disengage the power transmissions of the output-side first and second transmission mechanisms, respectively; a speed-change operating member capable of being operated within an area including a vehicle speed zero position, a first speed stage area and a second speed stage area that is arranged on a higher speed side than the first speed stage; a control device performing controls of the HST speed change actuator, the input-side clutch mechanisms and the output-side clutch mechanisms, wherein when the speed-change operating member is positioned in an area including the vehicle speed zero position and the first speed stage area, the control device causes the input-side first and second input-side clutch mechanisms to be brought into the engagement state and the disengagement state, respectively, thereby to realize a first HMT transmitting state in which the first element acts as a reference power input portion, which inputs a reference power from the drive source, and the second element acts as a combined power output portion, which outputs, toward the speed change output shaft, a combined rotational power, and then causes the output-side first and second clutch mechanisms to be brought into the engagement state and the disengagement state, respectively, thereby to operatively transmit the rotational power of the second element to the speed change output shaft, when the speed-change operating member is positioned in the second speed stage area, the control device causes the input-side first and second clutch mechanisms to be brought into the disengagement state and the engagement state, respectively, thereby to realize a second HMT transmitting state in which the second element acts as the reference power input portion and the first element acts as the combined power output portion, and then causing the output-side first and second clutch mechanisms to be brought into the disengagement state and the engagement state, respectively, thereby to operatively transmit the rotational power of the first element to the speed change output shaft, the planetary gear mechanism is so configured that the rotational speed of the rotational power output from the second element is zero when the rotational speed of the HST output is set to the first HST speed in the first HMT transmitting state, the input-side first and second speed change ratios are so set that the rotational speed of the second element at the time when the HST output is set to the second HST speed in the first HMT transmitting state is same as that of the second element driven by the rotational power that is operatively transmitted via the input-side second transmission mechanism in the second HMT transmitting state, and the rotational speed of the first element at the time when the HST output is set to the second HST speed in the second HMT transmitting state is same as that of the first element driven by the rotational power that is operatively transmitted via the input-side first transmission mechanism in the first HMT transmitting state, the control device operates the HST speed change actuator so that the HST output has the first HST speed according to the operation of the speed-change operating member to the vehicle speed zero position, and the HST output is accelerated according to the accelerating operation of the speed-change operating member from the vehicle speed zero position, and when the speed-change operating member is shifted up from the first speed stage area to the second speed stage area, the control device causes, at a first/second speed stage shift-up start time point when the drive rotational power has reached a predetermined first/second speed stage shift-up start speed, the second clutch mechanism of one clutch mechanism pair out of the input-side clutch mechanism pair and the output-side clutch mechanism pair to be instantly shifted from the disengagement state to the engagement, and causes, at a first/second speed stage shift-up end time point after an elapse of a predetermined time from the first/second speed stage shift-up start time point, the first clutch mechanism of the one clutch mechanism pair to be instantly shifted from the engagement state to the disengagement state, thereby to realize a shift-up double transmitting state in which both of the first and second clutch mechanisms in the one clutch mechanism pair are engaged during the period from the first/second speed stage shift-up start time point until the first/second speed stage shift-up end time point, and also causes, in the shift-up double transmitting state, the first clutch mechanism of the other one clutch pair out of the input-side clutch mechanism pair and the output-side clutch mechanism pair to be gradually shifted from the engagement state to the disengagement state while having the frictional plate being frictionally slid, and causes the second clutch mechanism of the other one clutch mechanism pair to be gradually shifted from the disengagement state to the engagement state while having the friction plate being frictionally slid, thereby to switch from the engagement state of the first clutch mechanism to the engagement state of the second clutch mechanism in the other one clutch mechanism pair.

2 . The transmission structure according to claim 1 , wherein the first/second speed stage shift-up start speed is set to a speed of the drive rotational power that is realized on the speed change output shaft via the output-side first transmission mechanism when the rotational speed of the HST output is set to the second HST speed in the first HMT transmitting state.

3 . The transmission structure according to claim 1 , wherein:
the input-side first and second clutch mech

Assignees

• Kanzaki Kokyukoki Mfg Co Ltd

Inventors

• Owada Kazuhiro
• Iwaki Koji
• Motooka Ryo
• Ogura Kohei
• Takahashi Takumi

Classifications

• F16H61/682

  with interruption of drive · CPC title

• B60Y2200/221

  Tractors · CPC title

• F16H47/04 Primary

  the mechanical gearing being of the type with members having orbital motion · CPC title

• F16H61/0437

  by using electrical signals (F16H61/0403 and F16H61/061 take precedence) · CPC title

• F16H61/46

  Automatic regulation in accordance with output requirements · CPC title