Kanzaki Kokyukoki Mfg. Co., Ltd.

Other

Yammar Co., Ltd.

Mizuya Matsufuji

Takumi Fujita

Katsunori Katou

Masahisa Kawamura

Gen Yoshii

In a traveling transmission in which an auxiliary transmission is interposed between a main clutch and a mechanical transmission, the auxiliary transmission is configured such that power transmission is cut out interlockingly with the disengagement operation of the main clutch. For example, the auxiliary transmission is configured as a high-low speed selector device including a hydraulic-operated first hydraulic clutch and a spring-operated second hydraulic clutch. Preferably, there should be provided a controller for changing the position of a direction switching valve for the first and second hydraulic clutches based on the operation of an operating member such as a pedal for disengaging the main clutch. According to the present invention, it is possible to shorten a time required for a speed change operation by the mechanical transmission and, also, to achieve a smooth operation by the mechanical transmission.

Traveling transmission of working vehicle

A hydraulic clutch assembly is equipped with a spring-drive hydraulic clutch, which includes a gear rotatably mounted on a transmission shaft and a clutch cylinder fixedly mounted on the transmission shaft, first and second friction elements respectively supported on the gear and the clutch cylinder in such a manner as to be slidable along an axis of the clutch (hereinafter sometimes referred to a clutch axis) and relatively non-rotatable thereto, a pressure disk disposed opposite to the friction elements, and a spring for moving the pressure disk towards the friction elements to bring the first friction element into engagement with the second friction element, in which the pressure disk is moved away from the friction elements by an effect of hydraulic pressure, thereby withdrawing the friction elements from engagement with each other.

Hydraulic clutch assembly

A speed change mechanism ( ) constructed by connecting in tandem a hydraulic type speed change unit ( ) having a plurality of hydraulic clutches ( ) to be alternatively engaged and a hydraulic type speed change unit ( ) having a plurality of hydraulic clutches ( ) to be alternatively engaged, wherein a time-varying region (common slip region) is secured in which the two clutches slip in common such that during speed change, when the working hydraulic pressure in a clutch to be engaged is on its way to gradual increase, the working hydraulic pressure in a clutch to be disengaged lowers. This common slip region is made smaller during shift-down than during shift-up by a change in time-difference between the pressure increase start time for the clutch to be engaged and the pressure decrease start time for the clutch to be disengaged or by a change in the pressure decrease property of the clutch to be disengaged.

Method of controlling hydraulic pressure in speed change mechanism having hydraulic clutches

In a front housing ( ) including at a front end portion thereof an engine flywheel ( ), there are provided a primary drive shaft ( ) which is co-axial with the flywheel, a transmission shaft ( ) which is parallel to the drive shaft, and an output shaft ( ) which is co-axial with the drive shaft. The output shaft is connected to a speed change mechanism ( ) in a transmission case ( ) succeeding to the front housing. A first supplementary speed change mechanism ( ) is disposed between the drive shaft and the transmission shaft, and a second supplementary speed change mechanism ( ) is disposed between the transmission shaft and the output shaft. One of these supplementary change mechanisms is formed into a direction-reversing mechanism, and the other change mechanism is formed into a high/low speed-selecting mechanism.

Transmission system in working vehicles

The present invention is so designed that a housing of a transmission which can drive front wheels and rear wheels and a power take-off shaft is constructed having a first chamber and a second chamber. A hydrostatic transmission is housed in the first chamber. A gear-type speed changing unit is housed in the second chamber. A hydraulic pump and a hydraulic motor are separately disposed on the inner and outer surfaces of the front wall of the first chamber. A clutch mechanism for engaging or disengaging with or from the front wheels for supplying power thereto is also provided. On the housing is provided a restraint mechanism for restraining rearward acceleration more than a predetermined speed by a speed control lever of the hydrostatic transmission when the gear-type speed changing unit is switched to the high speed setting. Left and right running brake units provided on the vehicle are made independently operable by treading left and right turn brake pedals on a first brake pedal shaft and made simultaneously operable by treading a master brake pedal on a second brake pedal shaft.

Transmission for a working vehicle

A slidable and rotatable first control shaft ( ) and a slidable and rotatable second control shaft ( ) for respectively shifting main and auxiliary speed change mechanisms ( ) project outwardly to one side of a vehicle housing ( ) and are connected respectively to a main change lever ( ) and an auxiliary change lever ( ) which are pivotally supported by a support member ( ) fixedly provided at one side of the vehicle housing. Preferably, the main change lever is disposed at a location where an operator on a seat ( ) can operate the lever easily whereas the auxiliary change lever is disposed at a location where the operator is hard to operate the lever. The support member is preferably composed of a cover member which surrounds the control shafts, lower portions of the change levers, and connecting members ( ) therebetween. An opening ( ) provided to the cover member for assembling the connecting members is closed by a closure member ( ).

Speed change control device for tractors

A speed change mechanism ( ) constructed by connecting in tandem a hydraulic type speed change unit ( ) having a plurality of hydraulic clutches ( ) to be alternatively engaged and a hydraulic type speed change unit ( ) having a plurality of hydraulic clutches ( ) to be alternatively engaged, wherein a time-varying region (common slip region) is secured in which the two clutches slip in common such that during speed change, when the working hydraulic pressure in a clutch to be engaged is on its way to gradual increase, the working hydraulic pressure in a clutch to be disengaged lowers. This common slip region is made smaller during shift-down than during shift-up by a change in time-difference between the pressure increase start time for the clutch to be engaged and the pressure decrease start time for the clutch to be disengaged or by a change in the pressure decrease property of the clutch to be disengaged, and is maintained constant irrespective of whether one or two hydraulic clutches are engaged and disengaged during speed change respectively or irrespective of a difference in engine rpm.

Method of controlling hydraulic pressure in speed change mechanism having hydraulic clutch

Two fluid-operated supplementary speed change mechanisms ( ), one of which is formed into a direction-reversing mechanism and the other of which is formed into a high/low speed-selecting mechanism, are provided in a front housing at locations before and behind a bearing support wall ( ) which divides the inside of the front housing into front and rear chambers. Two transmission shafts ( ), on which fluid-operated clutches ( F, R, ) of the supplementary speed change mechanisms are mounted, are disposed non-coaxially and are supported by the bearing support wall, and rotary joints ( F, R, L, H, L) for connecting fluid passages ( F, R, L, H, L) in the transmission shafts, which passages are in fluid communication with the fluid-operated clutches, to stationary fluid passages are formed in outer circumferences of the transmission shafts within an inside of the single bearing support wall.

Transmission assembly for working vehicles

A drive gear ( ) having integral drive teeth ( ) is rotatably mounted on a transmission shaft ( ) for transmitting power to front wheels, and a movable clutch member ( ) having integral driven teeth ( ) engageable with the drive teeth is slidably but non-rotatably mounted on the transmission shaft. A spring ( A) for biasing the movable clutch member into a direction of causing engagement of the driven teeth with the drive teeth is inserted at a part thereof into an axial bore ( ) in the clutch member. A piston ( ) is slidably fitted in a cylinder member ( ) which is fixedly mounted on the transmission shaft at a radially inward location of the drive and driven teeth. The transmission shaft includes a fluid passage ( ) which applies fluid pressure to the piston such that the piston is moved so as to move the movable clutch member into a direction of causing disengagement of the driven teeth from the drive teeth. The front wheel drive clutch of this structure is small in the number of parts, is compact in its axial length, and is rich in durability.

Front wheel drive clutch for tractors

In a front housing ( ) including at a front end portion thereof an engine flywheel ( ), there are provided a primary drive shaft ( ) which is co-axial with the flywheel, a transmission shaft ( ) which is parallel to the drive shaft, and an output shaft ( ) which is co-axial with the drive shaft. The output shaft is connected to a speed change mechanism ( ) in a transmission case ( ) succeeding to the front housing. A first supplemetary speed charge mechanism ( ) is disposed between the drive shaft and the transmission shaft, and a second supplementary speed change mechanism ( ) is disposed between the transmission shaft and the output shaft. One of these supplementary change mechanisms is formed into a direction-reversing mechanism, and the other change mechanism is formed into a high/low speed-selecting mechanism. Preferably, the front housing includes a first bearing support wall ( ) disposed before the first supplementary change mechanism, a second bearing support wall ( ) disposed between the first and second supplementary change mechanisms, and a third bearing support wall ( ) disposed behind the second supplementary change mechanism. The second and third bearing support walls are removably secured. Preferably, the second supplementary change mechanism comprises a fluid-actuated clutch ( ) and a spring-actuated clutch ( ) which are supplied with fluid pressure through a single fluid passage ( ) in the transmission shaft.

A transmission for a working vehicle like a tractor of the invention is housed in a transmission housing,interposed between an engine and a rear axle housing,. An interior of transmission housing,is divided into a front chamber A and a rear chamber B through a partition wall,. In front chamber A is disposed a main-clutch system partition centering a traveling-input shaft,. In rear chamber B is disposed a speed-changing system as a combination of reversing arrangement and multi-speed-changing arrangement. In a rear-opening of housing,is disposed a bearing plate,. In rear chamber B, a first speed-changing shaft,, a second speed-changing shaft,and a front transmission output shaft,are supported in parallel between wall,and plate,. A regular speed-reduction gear train and a reversing speed-reduction gear train are interposed ed between shafts,and,, so that shafts,and,can be connected with each other through one of the gear trains by a first clutch device C,on shaft,. A second clutch device C,is on shaft,so as to selectively connect shafts,and,directly. A plurality of gear trains for multi-speed stages are interposed between shafts,and,, so that shafts,and,are connected with each other through one of the gear trans by a third clutch device C,on shaft,. A cover,is settled on housing,. A main (second) speed-changing lever,and a sub (first) speed-changing lever,are disposed respectively at both lateral sides of cover,. Third clutch device C,is operated by lever,. First and second clutch devices C,and C,are selectively operated by lever

A four-wheel driven wheel has a rear-wheel driving system branching at the intermediate thereof into a front-wheel driving system comprising a first transmission for driving the front wheels at a peripheral speed substantially identical with that of the rear wheels and a second transmission for driving the front wheels at a peripheral speed higher than that of the rear wheels. A hydraulic clutch device is provided, including a hydraulically operable first friction clutch for connecting and separating the first transmission with the rear-wheel driving system, a hydraulically double-acting first piston for engagement and disengagement of the first friction clutch, a first fluid chamber for the clutch-engaging action provided at one side the first friction clutch, a second fluid chamber for the clutch-disengaging action provided at the other side thereof, and a biasing member for biasing the first friction clutch to engage disposed in the first chamber. A second clutch device is also provided including a hydraulically operable second friction clutch for connecting and separating the second transmission with the rear-wheel driving system, a hydraulically single-acting second piston for engagement of the second friction clutch, and a third piston provided at one side of the second piston for the clutch-engaging action thereof. A directional control valve is provided which is operable to be put into one of three positions: a first position wherein fluid is supplied to the first chamber; a second position wherein fluid is supplied to the second chamber; and a third position wherein fluid is supplied to the third chamber.

Four-wheel driven vehicle

A traveling operation device for a vehicle, wherein a cruising control mechanism, which can artificially hold a speed changing instrument of a stepless transmission biased toward the neutral side in a desired speed change position and which is interlocked to be released by treading a master brake pedal, is disposed at one lateral side within a dashboard, and a parking locking mechanism, which can hold the master brake pedal in a treading position, is disposed at the other lateral side within the vehicle dashboard.

Traveling operation device for a working vehicle

A four-wheel drive vehicle includes a first transmission system for transmitting power from an engine to a left and a right first driving wheel provided with a braking unit, and a second transmission system branching off from the first transmission system to transmit power to a second pair of driving wheels serving as steerable wheels. The second transmission system is provided therein with a frictional transmission passage having a frictional torque, which is smaller than that between the second driving wheels and a road surface, and a direct transmission passage disposed in parallel with the frictional transmission passage, so that either passage can be selected. The frictional transmission passage is selected when a speed-changing operating tool is set to its high speed position or when a steering device is operated beyond a predetermined angle, and the direct transmission passage is selected in all other cases.

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Sanda, Japan

Mizuya Matsufuji