JPH08188059A - Transmission of earthwork vehicle - Google Patents

Abstract

PURPOSE: To control a steering wheel and make shifts without taking both hands off the steering wheel. CONSTITUTION: A push-switch type downshift switch 21 is provided on a knob 4 projected from a steering wheel 1. While the steering wheel 1 is being controlled by gripping the knob 4 of the steering wheel 1 by the left hand, cargo operating levers 2, 3 are operated by the right hand. When it is desired to downshift to first gear, the downshift switch 21 is pressed with the knob 4 kept gripped, and then the transmission downshifts to first gear.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change device provided with a down shift switch and a speed change switch in an earthmoving vehicle such as a wheel loader.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 3-3002 is a conventional transmission for earthmoving vehicles such as wheel loaders and shovel loaders.
As disclosed in Japanese Patent Laid-Open No. 4, there is one in which a downshift switch is attached to the cargo handling operation lever so that the vehicle speed can be switched while operating the cargo handling operation lever. In addition, as shown in FIG.
0 is attached to the tip of the forward / reverse and shift switching lever 53 arranged on the post 52 that supports the steering wheel 51, or the downshift switch 50 is a foot switch as shown in FIG. 6B. There is something.
In the figure, 54 is a cargo handling lever, and 55 is a seat.

[0003]

However, in a large-sized wheel loader or the like, two cargo handling operation levers, one for the boom and one for the bucket, are usually arranged near the right side of the steering wheel, and the steering wheel is operated by the left hand. It operates by alternately holding the cargo handling control lever with the right hand. Therefore, the above-mentioned Japanese Patent Publication No.
If a downshift switch or the like is provided on one of the two cargo handling operation levers (for example, a boom lever) as described in Japanese Patent No. 4 publication, when performing the cargo handling work while operating the steering wheel, the bucket lever is being operated. In order to operate the downshift switch, it is necessary to change the right hand to the boom lever, which is a complicated operation and lacks safety.

Although it is possible to provide downshift switches on both the boom lever and the bucket lever, the circuit and control for electrically connecting the two downshift switches are complicated, the number of parts is increased, and the manufacturing cost is increased. There was a problem that was expensive.

On the other hand, even if a downshift switch is attached to the forward / reverse switching lever or is used as a foot switch, it is necessary to change the holding of the hand or the foot to operate the downshift switch. I didn't like it.

In view of the above, an object of the present invention is to provide a gear shift device for improving downshift and gear shift operability in an earthmoving vehicle such as a large wheel loader having a plurality of cargo handling operation levers.

[0007]

According to the means for solving the problems of the present invention, as shown in FIG. 1, a downshift switch 21 for shifting from a speed stage other than the first speed to the first speed is attached to the knob 4 of the steering wheel 1. Is.

Further, as shown in FIG. 4, rotary switches 26 and 27 for gradually shifting each speed stage or forward and backward are attached to a knob 28 of the steering wheel 1.

[0009]

In the above means for solving the problem, the steering wheel 1 is operated while holding the knob 4 with one hand, and the cargo handling operation lever is operated with the other hand to perform the cargo handling work while the vehicle is traveling. Here, when it is desired to shift down the vehicle speed to the first speed, the downshift switch 21 may be pushed with one hand while holding the knob 4.

Further, when the rotary switches 26 and 27 are attached, forward or backward or each speed stage can be switched by moving the forward or backward or each speed stage rotary switch 26 or 27 with one hand while holding the knob 28. .

[0011]

【Example】

(First Embodiment) A large wheel loader which is an earthmoving vehicle according to a first embodiment of the present invention includes a cargo handling device such as a bucket arranged on the front surface of a vehicle body, an engine, a manual transmission (transmission), and wheels from these. It is provided with a drive transmission mechanism that transmits a driving force, and a shift change device that changes the transmission. Then, in the driver's seat on the upper part of the vehicle, as shown in FIG. 1, two separately provided cargo handling operation levers 2 for boom and bucket for operating the cargo handling device are arranged near the right side of the steering wheel 1. The left hand operates the steering wheel 1 and the right hand operates the cargo handling lever 2,
It is designed so that 3 can be held alternately and operated.

Further, the steering wheel 1 is provided with a hemispherical knob 4 for facilitating the turning operation of the vehicle, and the steering wheel 1 can be operated by holding the knob 4 with the left hand. ing. In the figure, 5 is a steering wheel post that supports the steering wheel, and 6 is a seat.

The gear shift device is a device for switching the transmission for controlling the vehicle speed by a plurality of speed and forward / reverse actuators (hereinafter referred to as fluid pressure clutches).
As shown in FIG. 2, solenoid valves 7 to 12 for forward and backward movement and each speed stage for operating each fluid pressure clutch individually or in a certain combination, and each solenoid valve 7 via the control circuit 13.
Shift switches 14 to 19 for turning on and off switches 12 to 12 to operate each fluid pressure clutch.

The shift changeover switches 14 to 19 are a forward (F) switch 14, a reverse (R) switch 15, a first speed switch 16, a second speed switch 17, and a third speed switch 1.
8 and a fourth speed switch 19. Then, as shown in FIG. 1, a well-known forward / reverse speed stage switching lever 20 (hereinafter, referred to as a shift switching lever) for switching each of these switches.
Is arranged on the steering wheel post 5 so that it can be operated with the left hand. That is, the forward switch 14 is turned on when the shift switch lever 20 is tilted to the rear side, and the reverse switch 15 is turned on when the gear shift lever 20 is tilted to the front side, and there is a neutral position between them. Further, each of the speed stage switches 16 to 19 is a rotary switch and is arranged at the tip end side of the speed change lever 20. By rotating the rotary switch, the speed is changed in the order of first speed → second speed → third speed → fourth speed. It It should be noted that, instead of the gear changeover lever 20, two levers for forward and backward movement and for a speed stage are used, or one lever is used to switch between forward first, second, third, fourth speed, reverse first and second speed, It may be done.

In addition, the gear change device includes a forward switch 14
And the second speed solenoid valve 10 in the ON state of the second speed switch 17
The downshift switch 21 is provided to switch off the power supply to the first speed solenoid valve 9 and switch the power supply to the first speed solenoid valve 9. The downshift switch 21 is a push switch and is attached to the knob 4 of the steering wheel 1. As shown in FIG. 3, the downshift switch 21 is composed of a contact 23 mounted on a switch board 22 arranged in the knob 4 and an operation button 24 arranged on the surface of the knob 4 so as to be retractable. Is connected to the control circuit 13 via the wiring 25.

As shown in FIG. 2, when the reverse switch 15 is turned on while the forward switch 14, the second speed switch 17 and the downshift switch 21 are on, the control circuit 13 disconnects the first speed solenoid valve 9 from being energized. It has a function of energizing the solenoid valve 10 for speed.

In the above structure, first start the engine,
When the shift switch lever 20 is operated to turn on the forward switch 14 and the second speed switch 17, the vehicle shifts to the second forward speed and the vehicle starts. However, at this time, the vehicle may be started with the first speed set.

Then, the knob 4 of the steering wheel 1 is grasped with the left hand, and the right hand holds the cargo operation levers 2 and 3 for the boom or the bucket alternately to perform steering operation and lever operation while the vehicle is running. Cargo work. Here, move the vehicle forward toward the earth and sand, run at the second speed until just before the plunge, and switch the speed stage from the second speed to the first speed at the same time to obtain a large plunging force immediately before the plunge, and at the same time operate the bucket Make a scoop. At this time, hold down the knob 4 of the steering wheel 1 with your left hand and use the downshift switch 21 with your palm.
When is pressed, the second speed solenoid valve 10 is de-energized, the first speed solenoid valve 9 is simultaneously energized, the speed stage is changed from the second speed to the first speed, and the cargo handling operation levers 2 and 3 are operated with the right hand. Scoop earth and sand. When the scooping is completed, the gear changeover lever 20 is operated to turn on the reverse switch 15, so that the first speed solenoid valve 9 is de-energized and the second speed solenoid valve 10 is energized to return to the second speed.

In this way, by disposing the downshift switch 21 on the knob 4 of the steering wheel 1, the cargo handling operation levers 2 and 3 are operated by the right hand, and the downshift is performed by the palm of the left hand while operating the steering wheel with the left hand. The switch 21 can be pressed.

Therefore, the operation of the right hand which has been troublesome until now is only the operation of the cargo handling operation levers 2 and 3, and the downshift switch 21 is operated while the steering wheel 1 is being operated by the left hand, and the steering wheel operation, the cargo handling operation and the down operation are performed. Since three types of shift operations can be smoothly performed, and erroneous operations are reduced, operability and safety are improved, and work efficiency as an earthworking vehicle is also improved.

(Second Embodiment) In the speed change device of the first embodiment, since the speed change lever 20 is separately provided on the steering wheel post 5, the forward / backward movement and speed are performed separately from the steering wheel operation and the cargo handling operation. Although it is necessary to perform the operation for switching separately, the steering wheel operation and the downshift operation can be performed with the left hand at the same time, but in order to change the gear shift, the hand must be released from the steering wheel, which still poses a problem in operability. I have left.

Therefore, in the gear shift device of the present embodiment, as shown in FIGS. 4 and 5, the gear shift lever 20 is eliminated, the forward / reverse switch is the forward / reverse rotary switch 26, and each speed stage switch is a speed stage rotary. As the switch 27, the downshift switch 21 and the box-shaped knob 28 are provided. Each of the rotary switches 26 and 27 and the downshift switch 21 has an operation knob arranged on one side surface of the knob 28, and each contact is connected to a control circuit via wiring in the same manner as that shown in FIG. It is connected. By rotating the forward / reverse rotary switch 26, the speed is sequentially switched to F → N → R, and each time the speed stage rotary switch 27 is rotated, the first speed → the second speed → the third speed → the fourth speed or the fourth speed → the third speed → the second speed → the first speed. It switches to high speed one after another.

In the above structure, the knob 28 is held by the left hand and the steering wheel 1 is operated while the right hand 2 is pressed.
A cargo handling lever 2 for book booms or buckets,
Hold 3 alternately and operate the lever. At this time, each time the speed stage rotary switch 27 is turned with a finger while holding the knob 28 with the left hand, the speed stages are sequentially switched. Further, when the forward / reverse rotary switch 26 is turned, the forward mode is switched to the neutral mode, and the neutral mode is switched to the reverse mode. here,
If the speed stage is returned to the second speed when the forward / reverse movement is switched, the start after the forward / rearward movement is smoothly performed. The other configurations and operations are the same as those in the first embodiment, and the members having the same functions as those in the first embodiment are designated by the same reference numerals.

Since the forward / reverse rotary switch 26, the speed stage rotary switch 27, and the downshift switch 21 are arranged on the knob 28 of the steering wheel 1 as described above, the steering wheel 1 is operated by the left hand and the cargo handling operation lever is operated by the right hand. The forward / reverse and speed stage rotary switches 26 and 27 and the downshift switch 21 can be pushed with the finger of the left hand while operating a few. Therefore, the steering wheel operation, the cargo handling operation, the downshift operation, and the gear shift operation can be smoothly and surely performed,
It is possible to improve operability and safety.

The present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes are made to the above embodiments within the scope of the present invention. For example, the speed change devices of the first and second embodiments are not limited to the application of a large wheel loader, and when applied to an earthmoving vehicle having a plurality of cargo handling operation levers such as a large excavator loader, the operability is improved. Can be planned. Further, the downshift switch may shift down from the third speed or the like to the first speed or the second speed.

Further, the speed stage rotary switch of the second embodiment may be two push switches for up-shifting and down-shifting so that the up-shifting and down-shifting operations can be performed quickly. Further, only one of the forward-reverse rotary switch and the speed stage rotary switch may be arranged on the knob.

[0027]

As is apparent from the above description, according to the present invention, the steering wheel is operated by disposing the downshift switch, the forward / reverse switch, or the speed change switch for switching the respective speed stage switches on the steering wheel knob. When carrying out cargo handling operations while carrying out, the transmission can be easily switched without changing hands or removing the steering wheel or cargo handling lever. The operation can be performed smoothly, the operability is improved, and the work efficiency as an earthwork vehicle is also improved.

[Brief description of drawings]

FIG. 1 is a layout view of a downshift switch in an earthmoving vehicle according to a first embodiment.

FIG. 2 is a control circuit diagram of a gear change device.

FIG. 3 is a sectional view of a steering wheel knob.

FIG. 4 is a layout view of a shift changeover switch and a downshift switch according to a second embodiment.

FIG. 5 is a perspective view of a knob

6A is a diagram showing a driver's seat of an earthworking vehicle in which a downshift switch is arranged on a switching lever, and FIG. 6B is a diagram showing a driver's seat of an earthworking vehicle in which the downshift switch is a foot switch.

[Explanation of symbols]

 1 Steering wheel 2 Boom lever 3 Bucket lever 4,28 Knob 21 Downshift switch 26 Forward / reverse rotary switch 27 Speed stage rotary switch

Claims (2)

[Claims] 1. An earthmoving vehicle having a downshift switch for shifting from a speed stage other than the first speed to the first speed, wherein the downshift switch is attached to a knob protruding from a steering wheel. Vehicle speed change device. 2. A shift switch for switching between transmissions by actuating a plurality of speed-step and forward-backward actuators is provided, and the shift switch is a rotary switch and is provided on the steering wheel in a protruding manner. The gear shift device for an earthmoving vehicle according to claim 1, wherein the gear shift device is attached to a knob.