JPH0220463A - Steering device for agricultural vehicle - Google Patents

Abstract

PURPOSE:To reduce a turning radius on a weak road, etc. and to enable a smooth steering by detecting the torsion of the torsion bar inserted into a steering shaft and automatically operating a brake of a steering side at the time of the steering operation power being more than specified value. CONSTITUTION:A torsion bar 22 is inserted into the steering shaft 20 linked to a steering wheel 19 and an operation power sensor 5 detecting a steering operation power by detecting the torsion of the torsion bar 22 thereof is provided. When the steering operation power by the operation power sensor 5 becomes larger than a preset value, braking is automatically executed on the heel of a steering side, i. e., turning inside by the shift operation of a solenoid switching valve. At the steering operation time on a weak road, etc. a braking force is automatically given to the wheel of a turning inside, the turning radius is reduced and a smooth steering can be made possible.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a steering system for an agricultural vehicle.

A brake system that supplements the steering by a steering device that steers the vehicle in the direction of travel can be used, for example.

Prior Art and Problems to be Solved by the Invention Conventionally, the steering of agricultural vehicles in the direction of travel has been
Basically, this is done by changing the direction of the front wheels by operating the steering wheel of the steering device, but especially when making headland turns in fields with soft soil, etc.
If only the steering wheel is operated, the brake on the rear wheel on the inside of the turn will not be able to stop, causing the turning radius to become larger, so normally the steering brake system for the rear wheel on the inside of the turn is activated by the force applied to the brake pedal. Recently, the steering braking device of the rear wheel on the inner side of the turn is automatically operated in accordance with the steering angle of the front wheel to provide steering assistance during such turns. There are examples where this is done. However, these actions are very troublesome in the previous week as they require an artificial pedal force action each time, and even in the latter case, if the steering angle does not reach a predetermined value or more, the soil surface condition is soft. The steering assistance function cannot be activated automatically when a large steering operation force is required in order to quickly operate the steering wheel due to width shifting, etc. There was an issue.

Therefore, the present invention provides a steering assistance effect by operating the steering brake device of the rear wheels based on the steering operation force rather than the steering angle, when an operation force of more than a preset normal level of cargo handling is detected. This invention operates the steering brake devices (3) of the left and right rear wheels (2) by the depression force of the left and right brake pedals (1). When the steering force of the steering device (4), which performs steering steering in the direction of travel, reaches a preset normal level of the load in the agricultural vehicle, an operation is performed to detect this steering force. A force sensor (5), and a brake FtJj control IAL (6) that automatically operates the steering brake device (3) on the steering side based on the detected value of the operating force sensor (5) to supplement the steering. The structure of the steering device is provided with:

Functions and Effects of the Invention According to Section 41a above, when the running speed of an agricultural vehicle is set mainly in a low speed range during work, the steering 9
2! (4) When turning action by steering wheel operation, especially headland turning in fields with soft soil surface, the operating force of the steering wheel is detected by the operating force sensor (5) and this detected value is detected. is sent to the brake UIJl device (6).

For example, when the operating force of the steering wheel is larger than the normal level operating force set in advance for the brake control 'a equipment (6), that is, the operating force J of the steering wheel under normal field conditions, etc., the brake is applied. Based on the calculation results of the control device (6), the wheel on the steering side (inner side of the turn) (2)
By automatically operating the steering braking device (3) of the steering wheel, opening the rear wheels (2) and performing a steering assisting action of the steering wheel, it is possible to steer the steering wheel beyond a predetermined value as in the past. If the angle is not reached, the condition of the soil surface is soft and requires a large steering force, or when a large steering force is required to quickly operate the steering wheel due to congestion, etc. , there is no possibility that the steering assistance function will not be activated automatically, and when a load greater than the normal level of operating force is detected when operating the steering wheel, the steering assist function will be activated automatically at the same time by simply operating the steering wheel. Since the rear wheel (2) can be braked at the same time as required, there is no need to manually brake the rear wheel (2) as many times as necessary, and the turning radius can be kept to a minimum. This allows for smooth turning action.

EXAMPLE For the sake of convenience, a case where the present invention is applied to a tractor will be illustrated.

The output of the engine (8) mounted on the tractor body (7) is generated by a clutch housing (9) that houses the main clutches (a, ) and the main clutch (b) that turns on and off the E clutch (a). , to this clutch housing (9)
41% so that the transmission is transmitted to the transmission case (10) which is equipped with a transmission mechanism by the adjacent gear train (A).

Also, the gear train of this mission case (10) (
A) includes, for example, a forward/reverse switching shifter (C) that changes the forward/backward movement by νJ8, and a shift (L)-2nd speed (S) and a 3rd speed (T)-4.
Main gear shift chic (d), (e) for switching speeds (F) respectively
and sub-shift thick (f) and (g) that switch between ultra-low speed (LL) - low speed (■5) and medium speed CM) - high speed (H), respectively.
, a rotation sensor (11) that detects the rotation of the final gear (i) of the drive shaft (h), and a differential gear ffl (J).
The left and right steering brake devices (3) are arranged on the left and right counter shirts (k) protruding from the counter shaft (k), and the left and right wheel gears (m) and wheel A wheel shirt) (12) is arranged, and the left and right rear wheels (2) are respectively pivotally attached to the foil shirt (12), so that the gear change output from the gear train (A) is transmitted to the rear wheels (2). Make it compose.

In addition, working power is branched and transmitted to the PTO shaft (13) of the transmission system independent of the gear train (A) of the traveling transmission system, and there is a hydraulic lift door -jA (14) and three points at the rear of the vehicle body (7). A rotary tiller is an example of a working device that is connected to the soil surface by a link mechanism (15) so that it can be raised and lowered! (1B) is driven by the output from the PTO shaft (13) when the PTO clutch (0) is turned on and off.

Further, the engine (8) mounted on the front part of the vehicle body (7)
) is provided with a bonnet (17) that covers the
17) A steering wI device (18) is arranged at the rear end, and the steering wheel (+9) of the steering device (4) is positioned above this steering device (18), and the steering wheel (19) is used for steering. The left and right front wheels (21) of the vehicle body (7) @ section are connected from the shaft (20) via the son so that the steering wheel (21) of the steering shaft (20) can be steered.
18) An operating force sensor (5) that detects the steering operation force by inserting a torque lever (22) near the torque lever (22) and the torsion of the torque lever (22), and A steering angle sensor (23) for detecting the actual steering angle of this front wheel (2υ) is provided on the side.

In addition, the said control 4 Affi (18) F side deck (24)
On the right side of the surface, there are left and right pedal arms (1
a) The left and right brake pedals (1) with a foot pedal (lb) fixed to one end side are located close together, and the left and right sides can be operated independently or integrally by connecting them with a connecting device (25). The other end of the pedal arm (1a) is connected to one end of a pedal force spring device (2G) which bends in response to pedal force. The brake rod (27) is connected to the - end side of the rod (27) via the crank arm (28).
) is connected to the steering brake device (3) on the other end side. In addition, a pedal force sensor (29) that detects the pedal force by the deflection of the pedal spring device (28) is installed at a detectable position of the pedal spring device (2B), and the detected value of the pedal force sensor (29) is A control device (6) for receiving and performing arithmetic processing is built into the control device (18). Also, the left and right crank arms (2B)
The brake can be controlled at any position on the connection side of the brake rod (27)! The output signals from lt and (6) actuate the Tt magnetic switching valve (30) and the Ml magnetic pressure control valve (31), and a hydraulic power brake cylinder (32) is activated.
be configured by connecting them in an operable manner.

Further, the rear wheel (2) is located behind the control device (18).
A control seat (33) is provided at a position above the seat.

In addition, the brake control 1 device (6) is mainly equipped with a CPU (34) that performs central arithmetic control, and this CPU (34)
4) each of the above-mentioned sensors (11) on the input side.

(5), (23), (29), etc. are connected, and the respective solenoid valves (30), (31), etc. are connected to the output side to automatically switch the braking method using the brake pedal (1). Configure it as possible.

In the tractor configured as described above, the gear train (A) of the heavy duty case (io) is changed to the sub-shift chic (
f) and (g) to shift to very low speed (LL), low speed (L), and medium speed (hi), this speed change shift signal is transmitted to the brake control device i1t (6
), and through arithmetic processing of this signal, the magnetic switching valve (
30) to the left and right positions, and control the left and right steering brake devices (3) to be operated separately in response to the depression force of the left and right brake pedals (1),
Step force spring device (!8) using pedal force sensor (29)
A detection signal of the deflection is sent to the brake control device (6), and the magnetic positive pressure control valve 3 is controlled according to the amount of deflection, that is, the magnitude of the pedal force action by arithmetic processing of this detection signal.
The power brake cylinder (32) is actuated by pressure oil from the pressure control valve (31) via the switching valve (30), thereby operating the steering brake device (3) in a strong or weak manner.

In such a state, for example, when making a headland turn, the steering wheel (1θ) is manually rotated, and the steering force generated by this rotation is applied to the torsion shaft (20) inserted into the steering wheel. bar (22) (7) The twisted star is detected by the operating force sensor (5), and this detection 1fi 11 is applied to the brake control y2. Send this to M(6), this brake control device! (6) is compared with the normal level of steering operation force set in advance, that is, the operation force level of the steering wheel (!9) under normal field conditions, etc., and calculates the If it is determined that it is the operating force, the corresponding brake control! 1 device (6) controls the steering brake device (3) of the rear wheel (2) on the steering side, that is, on the inside of the turn, as described above. The power brake cylinder (32) is actuated to perform braking according to the action stroke, and the steering wheel (19) is used to perform a steering assist function, so that the soil surface condition is soft and a large steering operation force is required. When it comes to 41! Even when a large steering force is required to quickly operate the steering wheel (19), such as by moving the steering wheel (19), the rear wheels (2) will be automatically adjusted by simply operating the steering wheel (19). Since braking can be performed, there is no need to manually brake the rear wheels (2) whenever necessary, and the turning radius can be minimized to achieve smooth turning action42. .

Note that the vehicle speed in the region where the steering brake control (3) is automatically activated at the same time as the operation of the steering wheel (111) is determined by the rotation that detects the actual vehicle speed, without depending on the speed change signal as described above. A length of 4 m may be formed based on the detection signal from the sensor (XI).

In addition, when shifting to the high speed (H) shift position using the auxiliary shift shift (g) in order to drive on the road at high speed, this shift shift signal is sent to the brake control W device (l), and this Switching the electromagnetic switching valve (30) to a neutral position by signal arithmetic processing,
The left and right steering brake devices (3) are controlled to operate simultaneously by only the pedal force of the brake pedal (1) on one side, and the deflection of the pedal force spring device (26) by the pedal force sensor (29) is controlled. According to the amount detection signal, the power brake cylinder (3
Activate 2) strongly and weakly to v4! By doing ll,
For example, even if you forget to connect the left and right play pedals (1) using the connector (20) and apply pedal force only on one side, the left and right steering brake devices (3) will operate uniformly at the same time. Therefore, there is no danger of the vehicle body (7) turning suddenly due to one-sided braking, and the vehicle can be stopped safely and accurately!

Moreover, in the GAT 1/--n (A) in the mission case (10) as described above, the above-mentioned control type! (1
8) Single shift lever for forward and reverse (35)
A vQ8 section that can be switched with the shift lever (3
When switching between forward and reverse in step 5), the left and right steering brake devices (3) may be operated simultaneously at an intermediate position, that is, neutral. According to this structure, the gear train ( By keeping the rotation of gear train (A) as low as possible, the shock to the gear train (A) when switching is reduced, allowing for quick forward and backward movement! , I] It is possible to improve work efficiency and prevent damage to the gear train (A). Note that the shift lever (35
) in the neutral position of the steering brake device (3).
) may be provided with a separate release switch to release the automatic operation when unnecessary.

Further, since the steering brake N(3) of the present invention is added to an existing configuration, it has high reliability as a wheel braking device.

[Brief explanation of the drawing]

The figures show an embodiment of the invention, and Figure 1 is a side view;
Fig. 2 is a plan view, Fig. 3 is a partial side sectional view, Fig. 4 is a block diagram of the transmission mechanism, Fig. 5 is a block diagram of a part of the function ll1m, and Fig. 6 is a block diagram of the electric circuit. It is. In the figure, code (1) is the brake pedal, (2) is the rear wheel,
(3) shows the steering brake control, (4) shows the steering device, (5) shows the operating force sensor, and (6) shows the brake control device.

Claims (1)

[Claims] In an agricultural vehicle, the steering brake device (3) of the left and right rear wheels (2) is actuated by the pressing force of the left and right brake pedals (1), and the steering device (4) is used to steer the vehicle in the direction of travel. When the steering operation force exceeds the preset normal level load, the operation force sensor (5) that detects this operation force and this operation force sensor (
Based on the detected value of 5), the steering brake device (
3) and a brake control device (6) that automatically operates to supplement steering.