JPH076067Y2 - Front Wheel Breaking Angle Detector for Tractor - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial field of application The present invention is a four-wheel drive type tractor in which the front wheels are accelerated when the cutting angle of the front wheels exceeds a predetermined value when the aircraft is rotated. The present invention relates to an angle detector.

(B) Conventional technology Conventionally, when performing various works while the tractor is traveling straight ahead, and steering to the extent that the traveling direction is corrected during that time, the front wheels are synchronized with the rear wheels in the normal four-wheel drive state and It is already known that when the steering angle is increased during traveling, the detector detects it and the front wheel is accelerated by this detection signal to rapidly turn the vehicle body.

(C) Problems to be solved by the invention In general, the steering transmission system is composed of many parts joined together, and there are some manufacturing errors in those parts. It was difficult to detect the corner.

(D) Means for Solving the Problems The present invention relates to a tractor having a gearbox in a steering transmission system, and the outer circumference of a screw shaft that is installed in the gearbox and that rotates in conjunction with the turning operation of a handle. , The cam body is screwed so as to be movable only in the axial direction along a guide member attached to the gear box, and the cam body is provided with a dead zone portion and a sensed portion that expands in a tapered shape on both sides thereof. A cam groove is formed, and the sensing portion of the detection switch screwed into the gear box so as to be adjustable forward and backward is made to face the dead zone of the cam body, and the cam body is moved in the axial direction to move the cam body. The sensed part is configured to operate the sensing part of the detection switch, and the arm fixed to the detection switch is provided with a long hole centering on the detection switch so that the arm can be rotationally adjusted to the gear box. Screw on the above The position of the sensing portion of the detection switch with respect to the sensed portion of the cam body can be changed by adjusting the rotation of the cam to solve the above-mentioned problems.

(E) Action When the steering shaft is rotated by the handle, the screw shaft inside the gear box in the steering transmission system rotates,
A cam body screwed onto the outer periphery of the screw shaft advances and retreats in the axial direction along a guide member attached to the gear box.

When the front wheel turning angle is relatively small, as in the case of correcting the traveling direction when traveling straight ahead during work, the cam body moves forward and backward with its dead zone facing the sensing portion of the detection switch, and therefore does not perform a sensing operation.

Also, when the handle is turned a lot to rotate the aircraft, the cam body also advances and retreats significantly, and the tapered surface that is one of the sensed parts presses the sensing part of the detection switch, so the detection switch is turned on, The front wheel transmission is operated by this detection signal to increase the speed of the front wheels, so that the aircraft rapidly turns. If the handle is returned and rotated shortly before the aircraft has completed its rotation, the cam body will move in the opposite direction and the pressing of the detection switch by the sensed part to the sensing part will be released. The transmission is switched to return to the original four-wheel drive state.

When adjusting the detection timing of the detection switch, when the arm attached to the detection switch is rotated, the detection switch also rotates and moves back and forth with respect to the groove of the cam. Fluctuates, which allows the sensing timing to be adjusted.

(F) Embodiment An embodiment of the present invention will be described with reference to a four-wheel drive tractor shown in the drawings. 1 is an engine, 2 is a clutch housing, and an intermediate transmission case 3 is connected to a rear portion of the clutch housing 2. A steering mast 4 supporting a shaft 5a of a steering wheel 5 is provided in the front part of a driving part provided in the steering wheel shaft 7 and a lower part of a steering ring shaft 7 connected to a lower end of the shaft 5a via a universal joint 6 and a steering intermediate. A gear box 10 is interposed between the rear portion of the shaft 8 and a bevel gear 11 spline-fitted to the steering shaft 7 and a bevel gear 13 spline-fitted to the output shaft 12 in the gear box 10. The front part of the screw shaft 15 is engaged with the rear end of the output shaft 12 and connected by a pin 16, and the rear part is supported by the gear box 10 via a bearing 17.

The cam body 18 screwed to the screw shaft 15 has a guide groove 19 in the lower portion, and is composed of a flat dead zone portion 20a on the side and slopes 20b formed on both front and rear sides thereof in a tapered shape. A cam groove 20 is provided, and a guide pin 21 screwed into the bottom plate of the gear box 10 is fitted into the guide groove 19 so as to move back and forth without rotating.

Further, a detection switch 23 having a sensing portion 23a is screwed into a screw hole 22 formed in the side wall of the gear box 10, and a base portion of an arm 27 made of a plate is fastened to an outer portion thereof by an inner and outer nut 25.26. On the front end side of the arm 27, a circular arc-shaped long hole 28 centered on the detection switch 23 is formed, and a bolt 29
Is inserted into the elongated hole 28 and screwed into the gear box 10 so that the turning can be adjusted. An O-ring 30 is press-contacted between the gear box 10 and the nut 25 adjacent thereto. Reference numeral 31 is a universal joint that connects the output shaft 12 and the steering intermediate shaft 8.

When the steering wheel 5 is rotated to such an extent that the traveling direction is corrected while the vehicle is traveling straight to perform plow work or tilling work with the tractor, the screw shaft 15 also rotates in conjunction with the steering shaft 7. Since the rotation angle is small, the amount of forward / backward movement of the cam body 18 is also small.
20b and 20b do not contact the sensing portion 23a of the detection switch 23, the non-detection state is maintained, and the front wheel transmission does not operate.

Further, when the machine body is rotated to move to the next work stroke after the work of one stroke is completed, when the handle 5 is rotated a large amount, the rotation angle of the screw shaft 15 is increased, whereby the cam body is rotated.
Since the amount of forward and backward movement of the cam body 18 increases, the cam groove 20 of the cam body 18
One of the slopes 20b is the sensing portion 23a of the detection switch 23.
Press to turn it on.

The detection switch 23 is connected to a solenoid valve 33 of a flow divider valve 32 inserted in the hydraulic control circuit of the front wheel transmission shown in FIG.
And a ring gear 36 fixed to a cylinder extending rearward from the differential case, a brake shaft 37 formed of a differential shaft extending rearward from the differential device 35, and the cylinder and the brake shaft 37 integrally rotated. A ball 38 and a sleeve 39 that switch between a four-wheel drive state in which they are driven and a two-wheel drive state in which they are mutually rotatable, a shift arm 41 that is supported by a shift shaft 40 and that moves the sleeve 39 back and forth, and a brake shaft 37. And a differential shaft 43 which is a front wheel drive shaft that extends forward from the differential case and is transmitted to the front axle case. 39 is in a four-wheel drive state by pushing the ball 38 toward the front thereof.

Then, when the detection signal of the detection switch 23 is input to the solenoid valve 33 and turned on, the hydraulic oil from the pump P passes through the oil passage 45 to the cylinder having the shift shaft as a spool and the hydraulic clutch 42. Since the sleeve 39 is pushed rearward to be in the two-wheel drive state and the hydraulic crack 42 enters the clutch state after the braking state to stop the brake shaft 37, the front wheel is driven at double speed.

When the handle 5 is returned and rotated immediately before the completion of the airframe traveling, the cam body 18 moves in the opposite direction, the slope of the cam body 18 separates from the sensing portion 23a of the detection switch 23, and when it is in the non-detection state, the solenoid valve 33 operates. When the hydraulic clutch 42 is turned off, the hydraulic clutch 42 is disengaged, the sleeve 39 is moved slightly forward, and the normal four-wheel drive state in which the front wheels rotate in synchronization with the rear wheels is restored.

Also, when the detection switch 23 is assembled, or if the detection timing is defective, loosen the bolt 29 and move the arm.
When 27 is rotated, the detection switch 23 moves the cam groove 20 of the cam body 20.
Since it moves back and forth, the position at which the sensing unit 23a contacts the slope 20b changes, so that the opening / closing timing of the detection switch 23 can be adjusted. 46 is a step.

(G) Effect of the Invention In the tractor in which the gearbox is interposed in the steering transmission system as described above, the invention is provided on the outer circumference of the screw shaft which is incorporated in the gearbox and rotates in association with the rotation operation of the handle.
A cam in which a cam body is screwed so as to be movable only in the axial direction along a guide member attached to a gear box, and a dead zone portion and a sensed portion that expands in a tapered shape on both sides thereof are provided on the cam body. The sensing portion of the detection switch, which is formed in a groove and is screwed into the gear box so as to be adjustable forward and backward, faces the dead zone of the cam body, and the cam body is sensed by moving in the axial direction. Part is configured to activate the sensing part of the detection switch, and the arm fixed to the detection switch is provided with a long hole centering on the detection switch, and the arm is screwed to the gear box so as to be rotationally adjustable. The position of the sensing part of the detection switch with respect to the sensed part of the cam body can be changed by adjusting the rotation of the arm.
When adjusting the front wheel break angle detection timing of 23, by rotating the arm 27 externally without disassembling the gear box 10 in the assembled state, it is possible to accurately and extremely easily perform a minute adjustment while watching the tester. Can be done

Further, it is possible to easily change the cutting angle when the front wheels are accelerated, and the adjustment operation can be performed by the arm 27.
It can be performed lightly by pushing and pulling the tip of.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a transverse sectional view of a gear box, FIG. 2 is a vertical side view of the same, FIG. 3 is a side view, and FIG. 4 is a vertical plan view. FIG. 5 is a side view of the steering portion, FIG. 6 is a front view of the same as above, and FIG. 7 is a front wheel shift control circuit diagram. 5 ... Steering wheel, 7 ... Steering shaft, 10 ...
Gear box, 15 ... Screw shaft, 18 ... Cam body, 20 ... Cam groove, 20a ... Dead zone, 20b ... Sensed part (slope), 21 ...
… Guide member (guide pin), 22 …… Screw hole, 23 …… Detection switch, 23a …… Sensing part, 27 …… Arm

Claims (1)

[Scope of utility model registration request] 1. A tractor in which a gearbox 10 is interposed in a steering transmission system. A cam body 18 is geared around an outer circumference of a screw shaft 15 which is installed in the gearbox 10 and rotates in association with a turning operation of a handle. The dead zone portion 20a and the sensed portion 2 which is spread in a taper shape on both sides of the dead zone portion 20a are screwed into the cam member 18 so as to be movable only in the axial direction along the guide member 21 attached to the box 10.
0b and the cam groove 20 is formed, and the sensing portion 23a of the detection switch 23 screwed to the gear box 10 so as to be adjustable forward and backward is faced to the dead zone portion 20a of the cam body 18, The movement of the cam body 18 in the axial direction causes the sensed portion 20 of the cam body 18 to move.
b is configured to operate the sensing portion 23a of the detection switch 23, and the arm 27 fixed to the detection switch 23 is provided with a long hole 28 centered on the detection switch 23 so that the arm 27 is fixed to the gear box 10. It is screwed to the arm 27 so that it can be rotated.
A front wheel turning angle detection device for a tractor, wherein the position of the sensing portion 23a of the detection switch 23 with respect to the sensed portion 20b of the cam body 18 can be changed by adjusting the rotation of the.