JPH02274629A - Power transmitting method for front wheel of vehicle - Google Patents

Abstract

PURPOSE:To easily change to fit either specification and dispense with a drastic change of design by selectively running on either front wheel power cut off to cut off power transmission to front wheels or speed increasing drive to drive front wheel at a larger peripheral speed than that of rear wheels, at turning. CONSTITUTION:In a vehicle of specification to drive front wheels 7 at a twice speed at turning, a gear case 62 provided with a speed increasing mechanism 68 is mounted on the bottom wall 46 of a mission case 4. When a handle 5 is operated to the left at turning, the front wheel 7 is moved around a king pin. When the front wheels reach the steering angle, by action of a sensor 25 a control means 75 gives a command to a solenoid 72 to supply working oil to hydraulic clutch 36 with a solenoid valve 71 and the clutch 36 is in. Consequently, a tractor can quickly turn with a small radius, by driving the front wheels 7 at almost twice speed of the rear wheels 8. For cutting off power transmission to the front wheel 7 and driving the vehicle by independent action of the rear wheel 8 at turning, a cover 61 is mounted instead of the gear case 62. Then, even if the sensor 25 is on at turning, power transmission to the front wheel is cut off because of no speed increasing mechanism 68.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for transmitting power to front wheels of a vehicle.

(Prior Art) Some vehicles, such as tractors, are of the four-wheel drive type, which drive four wheels, front wheels and rear wheels, and are excellent for driving on rough terrain.

On the other hand, when turning, the front wheels are driven at approximately twice the circumferential speed of the rear wheels, causing damage to the ground with the front wheels.

(Problem to be Solved by the Invention) However, in conventional four-wheel drive vehicles, which increase the speed of the front wheels to double speed when turning, the rear wheels are driven solely by cutting off power to the front wheels when turning. Therefore, it was necessary to design and manufacture each model separately, and it was not possible to design most of the parts in common.

In view of these conventional problems, it is an object of the present invention to make it possible to easily change the speed and use either of the two.

(Means for Solving the Problems) The present invention provides front wheel power disconnection for cutting off transmission of power to the front wheels 7 when turning, and a front wheel power disconnection for cutting off power transmission to the front wheels 7 when turning, in a four-wheel drive vehicle that runs by driving front wheels 7 and rear wheels 8. 7 at a circumferential speed higher than that of the rear wheels 8.

(Function) During normal straight running, the hydraulic clutch 37 is connected and power is transmitted to the front wheels 7 in both cases shown in Figs. 1 and 2, so that the front wheels 7 and rear wheels 8 are driven Run.

When turning, the sensor 25 detects the turning angle of the front wheels 7. Therefore, in FIG. 2, the hydraulic clutch 36 is connected and power is transmitted to the front wheels 7 via the speed increasing mechanism 68.
rotates at a higher circumferential speed than the rear wheel 8.

However, in FIG. 1, even if the hydraulic clutch 36 is connected, the power to the front wheels 7 is cut off, and the front wheels 7 are in a free state.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
In the figure, ■ is a tractor body, which consists of an engine 2, a clutch housing 3, a transmission case 4, etc. 5 is a steering wheel, and 6 is a driver's seat. 7 is a front wheel, and 8 is a rear wheel.

As shown in FIG. 4, the front wheel 7 is attached via an axle 13 to a front wheel case 12 that is rotatably supported around a king pin 11 by gear cases 10 at both ends of the front axle case 9. The front wheel case 12 is connected to a steering arm 16 via a knuckle arm 14 and a tie rod 15, and the steering arm 16 is attached to a steering shaft 18 of a steering cylinder 17 that operates in conjunction with the handlebar 5. There is. Therefore, when the handle 5 is rotated, the front wheel 7 is moved to the king pin 1.
Steering operation is possible in one rotation. A front axle frame 19 supports the front axle case 9 via a pedestal 20.

A shaft portion 21 is protruded from the upper side of the gear case 10, and a fitting portion 23 of a bracket 22 of the front wheel case 12 is fitted onto the shaft portion 21 so as to be relatively rotatable. A sensor 25 is attached to the fitting part 23 to detect the turning angle of the front wheel 7 by relative rotation with the shaft part 21, and this sensor 25 is turned on when the turning angle of the front wheel 7 reaches 356 or 456. is configured to do so.

Inside the clutch housing 3, a main clutch 29 is provided as shown in FIG.
are incorporated, gears 33, 34, transmission shaft 35,
A front wheel power transmission system 39 consisting of hydraulic clutches 36, 37, an output shaft 38, etc. is incorporated. The main transmission 30 is of a constant engagement type with multiple sets of gear trains between a main shaft 40 and a sub-shaft 41, and transmits power to the left and right rear wheels 8 via a sub-transmission 31 and a rear wheel differential device 32. It is supposed to be done.

As shown in FIG. 1, the transmission shaft 35 and output shaft 38 of the front wheel power transmission system 39 are arranged in the longitudinal direction below the main transmission 30, and are connected to the transmission case 4 through bearings 42 and 43.
It is supported by partition walls 44 and 45.

As shown in FIG. 1, the hydraulic clutches 36 and 37 are provided at the front end of the transmission shaft 35 at a position corresponding to the opening 47 formed in the bottom wall 46 of the transmission case 4, and
It is incorporated into a clutch case 48 that is fixed to the transmission shaft 35. That is, the hydraulic clutch 36.37 includes a clutch case 48, pistons 49.50 fitted in the clutch case 48, springs 51.52 that bias each piston 49.50 in the return direction, and an output boss. 53 and 54, and a large number of temporary clutches 55 and 56 interposed between the clutch case 48 and the output boss parts 53 and 54. The output boss portion 53 is a gear 5 that is loosely fitted to the transmission shaft 35.
7, and the output boss portion 54 is provided integrally with the output shaft 3.
It is integrally provided with a gear 58 fixed at 8. The output shaft 38 is a propulsion shaft 59 that passes through the oil pan of the engine 2.
, power is transmitted to the front wheels 7 via a front wheel differential device etc. inside the front axle case 9. Opening 4 in bottom wall 46
7 is closed by a removable cover 61 by the port 1-60.

Note that FIGS. 1 and 5 show a model that cuts off the power to the front wheels 7 and drives the rear wheels 8 independently when turning, and the cover g+
If a gear case 62 is attached instead as shown in FIG. 2, it is possible to change to a double speed drive type during turning. That is, the gear case 62 includes an intermediate shaft 65 supported through bearings 63 and 64, and a speed increasing gear 66, 67 that is fixed to both front and rear ends of the intermediate shaft 65 and meshes with gears 57, 58. A mechanism 68 is incorporated. This speed increasing mechanism 68 is intended to increase the circumferential speed of the front wheels 7 to approximately twice the circumferential speed of the rear wheels 8 when turning.

FIG. 6 shows the hydraulic circuit of the hydraulic clutches 36, 37.

69 is a hydraulic pump, and 70 is a relief valve. 71 is a solenoid valve that controls the hydraulic clutches 36 and 37, and has solenoids 72 and 73, which supply hydraulic oil to the hydraulic clutch 36 when the solenoid 72 is energized, and to the hydraulic clutch 37 when the solenoid 73 is energized. It is configured as follows.

FIG. 7 shows the control system of the solenoid valve 71. 74 is a mode setting device, which has a first mode that drives only the rear wheels 8 when going straight and turning, a second four-wheel drive mode that drives the front wheels 7 and rear wheels 8 both when going straight and turning, and a normal mode when going straight. with four-wheel drive,
A third mode in which the front wheels 7 are driven at double speed when turning can be selected and set as desired. Control means 75 is configured to issue commands to the solenoids 72 and 73 in conjunction with a signal from the sensor 25 in accordance with the mode set by the mode setter 74. That is, this control means 7
5 issues a demagnetization command to the solenoids 72 and 73 in the first mode, issues an excitation command to only the solenoid 73 in the second mode, and issues an excitation command to the solenoid 73 when traveling straight in the third mode, and issues a command to excite the solenoid 73 when the vehicle is in the third mode. When the sensor 25 is turned on, an excitation command is issued to the solenoid 72.

In the above-mentioned configuration, if the model is designed to drive the front wheels 7 at twice the speed of the rear wheels 8 during turning, the gear case 62 equipped with the speed increasing mechanism 68 is attached to the bottom wall 46 of the transmission case 4 as shown in FIG. Attach to.

In this case, if the mode setter 74 is set to the third mode, the solenoid 73 is energized by a command from the control means 75 when the vehicle is traveling straight, so hydraulic oil is supplied from the electromagnetic valve 71 to the hydraulic clutch 37. Therefore, hydraulic clutch 3
7 is connected, and the front wheels 7 are driven in synchronization with the rear wheels 8.

When turning, for example, if the handle 5 is operated to the left,
The front wheels 7 are steered around the kingpin 11. and,
When the front wheel 7 reaches the turning angle shown by the imaginary line in FIG. connects. Therefore, power is transmitted to the front wheels 7 via the speed increasing mechanism 68, so the front wheels 7
The rear wheels 8 are driven substantially in tandem, allowing the tractor to make sharp turns in a small radius without damaging the ground. Of course, at this time, the hydraulic clutch 37 is disengaged.

In order to cut off the power to the front wheels 7 during a turn, leaving the front wheels 7 in a free state and driving the rear wheels 8 independently, as shown in FIG. 1, a cover 61 is installed in place of the gear case 62. The hydraulic circuit and control system will be used as is.

By doing this, when driving straight ahead with the sensor 25 off, power is transmitted to the front wheels 7 via the hydraulic clutch 37, but when turning, the sensor 25 is on and the hydraulic clutch 37
Even if G is connected, since there is no speed increasing mechanism 68, the power to the front wheels 7 is cut off, and the front wheels 7 become free. Therefore, it can be used as a two-wheel drive type that drives only the rear wheels 8.

In addition, as shown in FIG. 9, the gear 66 of the speed increasing mechanism 68
may be configured to be slidably provided on the intermediate shaft 65 and to be selected by fitting and removing the gear 66 with respect to the gear 57.

(Effects of the Invention) According to the present invention, there is a front wheel power disconnection that cuts off power transmission to the front wheels 7 when turning, and a speed increasing drive that drives the front wheels 7 at a circumferential speed higher than the circumferential speed of the rear wheels 8 when turning. Since the vehicle selects and runs according to the specifications, it can be easily changed to any specification, and there is no need for major design changes as in the past.

[Brief explanation of drawings]

1 to 8 illustrate one embodiment of the present invention, and FIGS. 1 and 2 are cross-sectional views of the front wheel power transmission system,
Figure 3 is a side view of the tractor, Figure 4 is a front view of the front axle case, Figure 5 is a configuration diagram of the power transmission system, Figure 6 is a hydraulic circuit diagram, Figure 7 is a block diagram of the control system, FIG. 8 is an explanatory diagram of the operation, and FIG. 9 is a configuration diagram of a front wheel drive system showing another embodiment. l...Tractor body, 7...Front wheels, 8...Rear wheels,
25...Sensor, 36.37...Hydraulic clutch, 3
9... Front wheel power transmission system, 61... Cover, 62...
- Gear case, 68... speed increasing mechanism, 75... control means.

Claims (1)

[Claims] (1) In a four-wheel drive vehicle that drives the front wheels (7) and rear wheels (8), there is a front wheel power disconnection that cuts off power transmission to the front wheels (7) when turning, and a front wheel power disconnection that cuts off the transmission of power to the front wheels (7) when turning. Rear wheel(
8) A method for transmitting power to a front wheel of a vehicle, characterized in that the vehicle is driven by selecting speed-up drive in which the vehicle is driven at a circumferential speed greater than the circumferential speed of item 8).