US 9,283,951 B2Granted

Speed change system for work vehicle

AssigneeKubota Corporation

InventorsSusumu Umemoto, Hisao Mukai, Nobushige Ichikawa, Takuya Inamori, Yushi Matsuzaki

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Abstract

A speed change system for work vehicle having a continuously variable transmission device selects a first change gear ratio which is set larger than a smallest change gear ratio, when an engine rotational speed is a first set rotational speed which is set equal or close to an idling rotational speed of an engine; retains the change gear ratio of the continuously variable transmission device at the smallest change gear ratio, when the engine rotational speed is equal to or above a second set rotational speed set on a high-speed side relative to the first set rotational speed; and makes the change gear ratio of the continuously variable transmission device larger between the first change gear ratio and the smallest change gear ratio, as the engine rotational speed at that moment becomes lower, when the engine rotational speed is between the first and second set rotational speeds.

Claims4

Dependent claims

A work vehicle comprising:

right and left rear wheels;
a continuously variable transmission device operable to change speed of traveling power of the vehicle steplessly;
right and left brake pedals, each of the brake pedals being operable to be pressed across a braking canceling region, a braking speed change region defined continuous with the braking canceling region, and a braking stop region defined continuous with the braking change speed region;
a right brake braking the right rear wheel with a braking force in accordance with a pressing operation amount the right brake pedal;
a left brake braking the left rear wheel with a braking force in accordance with a pressing operation amount the left brake pedal;
a pedal sensor for detecting a dual pressing operation position of the right and left brake pedals;
and
a vehicle speed control unit, wherein when the dual pressing operation position of the right and left brake pedals is within the braking change speed region, the vehicle speed control unit controls the continuously variable transmission device toward a decelerating side thereof, in accordance with a dual pressing operation amount of the right and left brake pedals within the braking change speed region.

5 more elements

A work vehicle comprising:

right and left rear wheels;
a continuously variable transmission device operable to change speed of traveling power of the vehicle steplessly;
right and left brake pedals, each of the brake pedals being operable to be pressed across a braking canceling region, a braking speed change region defined continuous with the braking canceling region, and a braking stop region defined continuous with the braking change speed region;
a right brake braking the right rear wheel with a braking force in accordance with a pressing operation amount the right brake pedal;
a left brake braking the left rear wheel with a braking force in accordance with a pressing operation amount the left brake pedal;
a vehicle speed sensor for detecting a speed of the vehicle;
a pedal sensor for detecting a dual pressing operation position of the right and left brake pedals;
and
a vehicle speed control unit for changing a change speed ratio of the continuously variable transmission device, wherein when the dual pressing operation position of the right and left brake pedals is within the braking canceling region, the vehicle speed control unit changes the change speed ratio of the continuously variable transmission device in such a manner that the speed of the vehicle detected by the vehicle speed sensor matches a control target vehicle speed.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/317,515Filed 27 Jun 2014 · continuation
Priority: JP 2010-01132921 Jan 2010
Published: US 2014/0378274 A125 Dec 2014
Granted: 15 Mar 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

B60W 10/196
Including control of braking systems: acting within the driveline, e.g. retarders
B60W 10/101
Including control of change-speed gearings: infinitely variable gearings
F02D 31/00
Use of speed-sensing governors to control combustion engines, not otherwise provided for
F16H 61/421
Involving adjustment of a pump or motor with adjustable output or capacity: motor capacity control by electro-hydraulic control means, e.g. using…

Family

Application12/968,639Parent of this continuation · filed 15 Dec 2010
Application13/889,733Parent of this continuation · filed 8 May 2013
US 2014/0378274 A1Pre-grant publication · published 25 Dec 2014
US 8,798,878 B2Parent of this continuation
US 8,447,479 B2Parent of this continuation
US 2011/0178684 A1Published application
US 2013/0275027 A1Published application
US 9,283,951 B2This patent

From the US filing history. Foreign family members aren’t listed.