JP3179133B2 - Work vehicle transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission for a work vehicle .

[0002]

2. Description of the Related Art Conventionally, an automatic transmission of a bulldozer includes a torque converter, a transmission, a control valve for controlling a speed stage of the transmission, and a vehicle speed detector (detecting the speed of the transmission output shaft to determine the vehicle speed. ) And a control device that receives a signal from the vehicle speed detector and transmits a signal to the control valve. When the vehicle speed reaches a predetermined value (shift point), the control device transmits a control signal. To change the speed of the transmission.

[0003]

THE INVENTION Problems to be Solved by the way, manual
The operator of a bulldozer with a variable transmission typically predicts the next changing load from land conditions and often changes the speed stage of the transmission before the load changes to account for it. For example, in the case where it is predicted that a large load is expected to be applied forward while traveling in the second speed, the operator shifts to the first speed in advance before the load is applied to the bulldozer to cope with the load. Is common. Further, depending on surrounding conditions such as terrain, there is a case where it is desired to continue running at the current speed stage even when the vehicle speed changes. However, since the conventional automatic transmission automatically shifts when the vehicle speed reaches a shift point, there is a problem that a shift operation that meets the intention of the operator is not performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a transmission device for a work vehicle that allows an operator to predict a load and perform a shift for taking measures in advance.

[0005]

In order to achieve the above object,
Transmission device for a working vehicle according to the present invention, drive from the vehicle speed detector
Receiving a fast signal, the vehicle speed signal reaches to a Jo Tokoro vehicle speed, the control signal
In transmission of a working vehicle having a control device for automatically controlling the outgoing to speed stage to the speed stage control valves of the transmission of the items, press
When the button is pressed, the push signal is input to the controller.
Provided with a down switch to the knob of the forward-reverse lever, control
When the button-type switch is kept pressed, the control
While receiving the signal, the vehicle speed signal from the vehicle speed detector
Control signal to maintain the current gear position regardless of the speed
Signal to the stage control valve, and the button type switch
When it is pressed twice, it is affected by the vehicle speed signal from the vehicle speed detector.
Instead of shifting to a gear one step below the current gear.
It is characterized in controller der Rukoto for transmitting a control signal to the speed stage control valve.

[0006]

According to the above arrangement, the knob forward-reverse lever of the transmission to the automatic transmission by the vehicle speed, a button switch to control the speed stage of the transmission is provided, between and its pressing and holding the button switch the shift When the button is pressed twice in succession, the gear shifts to the next lower gear, so that the operator can predict the load and control the speed gear to deal with the load in advance.

[0007]

EXAMPLES Hereinafter, the embodiments of the present invention with reference to the drawings. FIG. 1 is a configuration diagram of an automatic transmission, wherein 1 is an engine, 2 is a torque converter, 3 is a forward / reverse lever, 4 is a knob, and 5 is a button switch. 10 is a transmission, 11
Is a forward clutch, 12 is a reverse clutch, 13 is a 1st speed clutch, 14 is a 2nd speed clutch, 15 is a 3rd speed clutch, 16
Is a transmission output shaft rotation number detector for detecting vehicle speed, 17 is a horizontal shaft device, and 18 is a sprocket. Reference numeral 20 denotes an electronic modulation valve for controlling a transmission, reference numeral 21 denotes a reverse clutch valve, reference numeral 22 denotes a forward clutch valve, reference numeral 23 denotes a third speed clutch valve, reference numeral 24 denotes a second speed clutch valve, and reference numeral 25 denotes a first speed clutch valve. Reference numeral 26 denotes a control device, which is connected to the forward / reverse lever 3, the button type switch 5, the transmission output shaft speed detector 16, and each clutch valve of the electronic modulation valve 20. FIG. 2 is a perspective view of the forward / reverse lever 3 , 4 is a knob, and 5 is a button switch. Button type switch 5
When the switch is pressed, the switch is turned ON, and while the switch is kept ON, the control device 26 does not transmit a shift signal. When the switch 5 is continuously turned ON twice, A signal is transmitted to shift to the next lower gear than the first gear.

FIG. 3 is a running performance curve of a bulldozer.
The vertical axis indicates the traction force, and the horizontal axis indicates the vehicle speed. 31 is 1st gear, 32
Is the second speed and 33 is the third speed. As is clear from the figure, the performance curves of the respective speed stages intersect at points a and b. In the lower speed range than point a, the first gear 31 shows the maximum traction force, and the second gear between the points a and b. 32 indicates the maximum traction force, and in the high speed range from the point b, the third speed 33 indicates the maximum traction force. That is, if the gears are shifted with the point a and the point b as the shift points, the bulldozer always runs with the maximum traction force as indicated by the thick solid line.

Next, the operation will be described. In normal traveling, when the forward / reverse lever 3 is moved forward, the control device 26 sends signals to the forward clutch valve 22 and the first speed clutch valve 25 to start the vehicle at the first forward speed. When the vehicle gradually accelerates, the control device 26 receiving the signal from the transmission output shaft rotation speed detector 16 determines that the vehicle speed has reached the vehicle speed v1 corresponding to the predetermined shift point a, and the second speed clutch valve 2
4 to shift the transmission to the second speed. 2nd to 3rd
The shift to the high speed is performed in the same procedure when the vehicle speed reaches the vehicle speed v2 corresponding to the shift point b. The same applies to the case of reverse travel, and the vehicle is controlled to always run with the maximum traction. The operation of the above automatic transmission is the same as that of the conventional one.

When the operator wants to continue running at the current vehicle speed due to land conditions or the like, he keeps pressing the button-type switch 5. The control device 26 receives the signal from the button-type switch 5 to stop the operation of the automatic shift, and does not shift even if the vehicle reaches the vehicle speed corresponding to the shift point, and maintains the current speed stage. When the operator predicts that a heavy load will be applied and wants to set the speed stage to the next lower speed stage in advance, pressing the button-type switch 5 twice continuously,
Control device 26 receives the signal and shifts to the next lower gear position.

[0011]

As described above, according to the present invention, a button type switch is provided on the knob of the forward / reverse lever of the automatic transmission.
If the button-type switch is kept pressed, the current speed stage is maintained, and if the button is pressed twice continuously, the speed can be changed to the speed stage one stage below the current speed stage. If a shift is made and the operator wants to continue running at the current speed stage due to land conditions or the like, the button-type switch is kept pressed to maintain the current speed stage. The gear can be shifted to the next lower gear by pressing the expression switch twice in succession, and the gear can be shifted according to the operator's intention.
A transmission for a work vehicle is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a transmission according to the present invention.

FIG. 2 is a diagram showing a forward / reverse lever with a button-type switch.

FIG. 3 is a running performance curve of a bulldozer.

[Explanation of symbols]

1: engine, 2: torque converter, 3: forward and backward lever, 4: knob, 5: button switch, 10: transmission,
16: Transmission output shaft speed detector, 20: Electronic modulation valve, 26: Control device.

Continuation of the front page (56) References JP-A-57-140952 (JP, A) JP-A-61-131632 (JP, A) JP-A-62-131756 (JP, A) JP-A-56-53930 (JP JP-A-4-46262 (JP, A) JP-A-61-189844 (JP, U) JP-A-2-125257 (JP, U) JP-A-3-23247 (JP, U) JP 2-125069 (JP, U) Japanese Utility Model Showa 62-66964 (JP, U) Japanese Utility Model Showa 63-25862 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 59/00 -61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (1)

(57) [Claims] 1. A receives a vehicle speed signal from the vehicle speed detector, the vehicle speed signal
No. is reached to a Jo Tokoro speed, with a control device for automatically controlling the speed stage to disseminate a control signal to the speed stage control valves of the transmission
In a transmission of a work vehicle , a button for inputting a push signal to a control device when pushed.
A button switch is provided on the knob of the forward / reverse lever, and the control unit is configured to release the button switch when the button switch is continuously pressed.
While receiving the push signal, the vehicle speed signal from the vehicle speed detector
Control signal to maintain the current gear position regardless of the speed
To the step control valve, and the button-type switch
When pressed twice, it is related to the vehicle speed signal from the vehicle speed detector.
Instead of shifting to the next lower gear
Transmission for a working vehicle, wherein the control device der Rukoto for transmitting a control signal to the speed stage control valve.