JPH07113522B2 - Angle detector for agricultural tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a cutting angle detection device for an agricultural tractor that accelerates a front wheel rapidly when the machine body is rotated.

(B) Conventional technology Conventionally, as a cutting angle detecting device in an agricultural tractor that accelerates and rapidly turns the front wheels when rotating the machine body, a link is attached to a pitman arm or the like to detect the cutting angle. Those that have been done are already known.

Further, as disclosed in JP-A-58-110376, a hydraulic steering vehicle for a special vehicle such as a construction vehicle has a steering angle sensor for detecting a steering angle by connecting a potentiometer to a steering wheel, 2. Description of the Related Art A hydraulic traveling vehicle is known in which a hydraulic drive system is operated by angle detection to perform traveling work.

(C) Problems to be Solved by the Invention Since the cutting angle detecting device in the known agricultural tractor is exposed to the outside, mud, muddy water, dust or the like adheres to the device, resulting in malfunction and durability. Is inferior.

Further, since the steering angle sensor of the hydraulic steering vehicle disclosed in the latter publication detects the steering angle with a high-priced potentiometer, the potentiometer is externally attached to the case portion of the steering angle sensor. However, there are problems that the cost is high and the potentiometer is not sufficiently protected.

Therefore, the present invention solves the above-mentioned conventional problems and installs a detection mechanism for detecting the cutting angle of the front wheels in a gear case provided in the steering transmission system with a simple structure and performs good cutting angle detection for a long period of time. It is intended to provide a cutting angle detecting device in an agricultural tractor that can be used.

(D) Means for Solving the Problems The present invention has a transmission system provided in a front wheel drive system, the transmission system is detected by a front wheel turning angle detection device, and is switched according to the detection result. It is a tractor, and the input shaft 106 and the output shaft 120 that intersect in the steering transmission system are meshed via bevel gears 113, 119 attached to the respective shaft ends, and are rotatably supported by the gear case 107 so that the bevel gears 113, 119 mesh with each other. A screw shaft 126 for screwing a slide member 127, (145) to one shaft end of the both shafts 106, 120 in a space formed by
And a restricting member 147 for restricting the rotation of the slide member 127, (145) around the axis of the slide member 127, (145) due to the rotation of the screw shaft 126 in the space of the slide member 127, (145).
And a detection switch 137 for detecting the axial movement of the slide members 127, (145) is provided in the gear case 107, and the detection mechanism responsive to the rotation of the shafts 106, 120 is installed in the gear case 107. Solved the problem.

(E) Action When the steering handle is rotated to rotate the machine to the left or right, the shaft of the steering operation system rotates to either one, and the shaft moves to the left or right in the gear case. Rotate. The detection mechanism on the side corresponding to the rotation detects in one direction in the gear case, and when the detection value becomes a certain value or more based on this detection operation, the detection signal is transmitted to the receiver of the switching mechanism of the front wheel transmission. As a result, the switching mechanism of the front wheel transmission operates to accelerate the front wheels.

Further, the detection mechanism can be installed in a space inside the gear case 107 formed by the meshing of the bevel gears 113, 119 with a simple structure and compactly, and the detection mechanism is properly lubricated so that the detection operation is accurately performed. be able to.

(F) Embodiment Referring to the drawings, an embodiment of the present invention will be described. The power of the engine 1 is supported by the intermediate case 5 via the main clutch 2 and the gears 3 and 4 in the clutch housing 17, and the cylindrical shaft 6 is supported. The transmission is transmitted to the PTO transmission 8, the traveling main transmission 9, and the traveling auxiliary transmission 10 in the main transmission case 7, and the differential pinion shaft 11 drives the rear axle 13 via the differential mechanism 12 and the final transmission mechanism 14. The drive shaft 16 connected to the front spline of the diff-pinion shaft 11 by a joint 15 is supported by the gear 4 in the clutch housing 17 through the tubular shaft 6, and the gear 18 attached to the front end of the drive shaft 16 is in the lower portion. Gears
The cylinder portion extending rearward from the differential case 21 that accelerates the front wheels is driven by 19,20.

As shown in FIG. 1, the differential case 21 is housed in a speed change case 24 integrally formed in the lower portion of the clutch housing 17, and the front portion is supported by a bearing 22 in the clutch housing.
17, the rear portion is supported by a holder 25 screwed to the intermediate case 5 via a bearing 23, and the front side gear 26
The shaft 33 spline-fitted to a is transmitted to the front axle 32, and the front wheel differential mechanism 35 in the front axle 32 drives the front axle 34 via the reduction gear 36. Further, the brake shaft 37, which is spline-fitted to the rear side gear 26b, is inserted into and supported by a tubular portion 40 extending rearward from the differential case 21, and a conical hole 44 formed in the outer periphery thereof has a conical hole 44 ... Hole 42 ...
The balls 41, ... The hub 39 has an inclined surface on both sides of the inner circumference to prevent the balls 41, ... from falling off. The state shown in FIG. 1 is in the foremost position, and the ball 41 escapes from the conical hole 44 to interrupt the transmission. When the ball 41 ... Is pushed into the conical hole 44 ... by sliding to the rear by the shift fork 43, the cylinder 40 and the brake shaft 37 are locked and the rear wheel When the power is transmitted to the front wheels at substantially the same speed, the hub 39 is slid further rearward, and the balls 41, ... Are pushed toward the front of the hub 39, the power is transmitted to the front wheels and the front wheel acceleration standby state is set.

Also, a boss 46 that is spline-fitted to the rear of the brake shaft 37.
The inner circumference of the desks 45 ... constituting the desk brake is spline-fitted on the outer circumference of the mating plate 47, and the projections on the outer circumference of the mating plate 47. , Desk 45 ..., mating plate 47
Has a gap with respect to the boss 46 and is stopped by the stepped collar 48.

A cylinder 51 for operating the desk brake is sealed with an O-ring 52 in a hole 51 which is fixed to the front end of the intermediate case 5 and is formed near the lower portion of a plate 49 which is joined and connected to the clutch housing 17. Insert the piston 58 with the sealing 59 interposed in the cylinder 50, loosely fit the protrusion 58a on the outer periphery of the protrusion 58a into the groove of the holder 25, and insert the front part into the center hole of the piston 58. The shaft 63 fixed by the snap ring 62 projects into the rear intermediate case 5,
The return spring 60 interposed in the protruding portion is received by the washer 61 and the retaining ring 62, and is covered by the cap 64.

Further, the shift fork 43 is fixed to the shift rail 71 fitted in the holes 70, 70a provided in the clutch housing 17 and the holder 25 so as to be slidable back and forth, and the front end portion of the shift rail 71 is fixed. Is formed in the spool portion 73 of the switching valve, and both sides of its rear portion are formed as parallel cutout surfaces 74, and an R groove 75 is provided on the front end surface of the boss of the shift fork 43.

The front large diameter portion and the small diameter portion of the hole 70 are communicated with the outside by an oil supply port 76 and a discharge port 81, and a pipe 78 whose one end is connected to the front oil supply port 76 by a bolt 80 and packings 79, 79. The other end of the pipe 82 is connected to the solenoid valve 77a of the control valve 77 of the hydraulic circuit shown in FIG. The end is fitted and screwed into the intermediate case 5 as shown in FIGS. 1 and 4, and the tip is the cylinder.
In the joint 53 that is tightly inserted in the oil passage 54 that leads to the inside of 50,
It is connected by packings 79, 79 and bolts 80.

The base of the arm 84, the tip of which is fitted into the recess 83 of the boss of the shift fork 43, is fixed to the control shaft 88 which is supported in the hole 85 of the lower outer wall of the clutch housing 17 through the tubular body 86, A plurality of claws protruding from the inner end surface of the boss 87 fixed to the outer end of the control shaft 88 and a plurality of claws protruding from the outer end surface of the tubular body 86 mesh with each other with a gap in the circumferential direction, The end portion is urged to rotate in one direction by a winding spring 98 engaged with both, the claw is covered with a sealed collar 99, and the tubular body 86 is fitted in a circumferential groove 91 thereof. The plate 92 is positioned by screwing it onto the outer surface of the clutch housing 17 with a bolt 93, and the arm 94 fixed to the outer periphery is interlocked with an operating lever 95 arranged in the front part of the operating section by a telescopically adjustable rod 96. There is.

The steering handle 103 is a kingpin case through a shaft 104, a joint 105, a shaft (input shaft) 106, a gear case 107, an output shaft 120, a joint 108a, a shaft 108, a joint 109, a steering gear box 110, a pitman arm 110a and a tie rod 111. Is designed to be rotated.

Further, as shown in FIGS. 9 and 10, in the gear case 107, the bevel gear 113 and the bevel gear mounted on the shafts (the input shaft) 106 and the output shaft 120 are mounted in a crossed manner in a state of being axially supported. 1
In the space formed by this engagement, the output shaft 120 forms a screw shaft 126 extending laterally and is supported by the bearing 123, and the other is supported by the bearing 122. ing.

A slide member (slide nut) 127 screwed onto the screw shaft 126 has a groove 128 on the outer circumference, and the boss portions of a pair of left and right swing arms 130, 130 are fitted on both side walls of the gear case 107 with their shaft centers aligned. The pin 131, which is inserted and positioned by the snap rings 132 and 132, is projectingly provided on the inner surface of the boss portion of the inner swing arm 130 and inserted into the groove 128, is
_The pin 131 projecting on the inner surface of the boss portion of the outer swing arm 130 is offset by l ₂ downward from the axis of the screw shaft 126. Bolts 134 and 134, whose heads are spherical, are fastened to the tips of 130 and 130 by nuts 135 and 135 which are separated by l ₁ from the center of rotation, and the heads are spherical.
One switch (detection switch) 137 which is in contact with 36 and communicates with the solenoid valve 77a of the control valve 77 and which has an inexpensive ON / OFF operation type is screwed to face the detection mechanism. The gear case 107 has a simple structure and is compactly installed. The detection mechanism in the gear case 107 is well wetted with lubricating oil, and
It is protected from external obstacles and the like, and can perform excellent detection operation.

Since the outer peripheral portion of the slide member 127 is cut into two parallel surfaces, and the distance L ₁ between these cut surfaces is smaller than the distance L ₂ between the left and right pins 131 and 131, the pressure receiving pin 136 and the bearing are attached to the gear case 107. After assembling 123, swing arm 130, 130,
When the slide member 127 is screwed onto the screw shaft 126 in a posture rotated by 90 degrees from the used state and inserted together with the output shaft 120, the slide member 127 is assembled so that the cutout surface 129 passes between the pins 131 and 131. And then slide member 127
When it is rotated 90 degrees, the groove 128 fits into the pins 131 and 131, so that the bolt 141 is fitted into the hole 140 of the swing arm 130 for positioning, and the output shaft 120 is rotated and inserted to a predetermined position. Then, after that, the bevel gear 113 is spline-fitted, the shaft 106 is assembled in the state, and it is stopped by the retaining ring 118.

In this embodiment, the end face of the shaft 106 is also formed as a regulating member slidably abutting on the flat surface formed on the upper surface of the slide member 127, and the regulating member rotates the screw shaft 126. The accompanying rotation of the slide member 127 due to the movement is restricted and the movement in the axial direction is allowed.

In addition, when the swing arm 130 is one, the switch 1
One 37 is installed on each side.

In the above-mentioned agricultural tractor, when traveling on the road, if the operation lever 95 is set to the 2W position, the hub 39 will move to the first position.
The position shown in the figure is reached, and only the rear wheels are driven.When the operating lever 95 is set to the 4W position during work, the rear part of the hub 39 pushes the balls 41 ... into the conical holes 44. The front wheel is forcibly driven by rotating integrally with the shaft 33, and when the operating lever 95 is set to the rearmost front wheel speed-up standby position, the hub 39 pushes the balls 41 ... It will be in the standby state, the 4WD state will be maintained, and the steering handle to rotate the aircraft in this state
When 103 is rotated to either side, the front wheel is broken, and at that time, the screw shaft 126, which rotates integrally with the output shaft 120 of the gear case 107, moves the slide member 127 forward or backward, and one swing arm. 130 swings forward, the other swing arm 130 swings backward by the same angle, and the bolt 134 at the lower end of the swing arm 130 swinging forward moves to the pressure receiving pin 136.
Press switch 137 via. This switch 137 does not turn on when the cutting angle of the front wheels is small and the pushing amount is small like when correcting the traveling direction, but it turns on when it exceeds the predetermined cutting angle set. Has become
When the turning angle of the front wheels becomes more than a predetermined value and turns ON during traveling of the machine body, the solenoid valve 77a of the control valve 77 turns ON and the hydraulic oil pumped by the pump P is pressed into the front hole 70 through the pipe 78. To be done.

At that time, since the spool portion 73 of the shift rail 71 is fitted into the small diameter portion of the hole 70 by setting the operation lever 95 described above, the shift rail 71 moves rearward to move the hole 70 and the discharge port.
Simultaneously with the communication with 81, the hub 39 moves rearward to be in the unlocked state, the hydraulic oil is press-fitted into the cylinder 50 through the pipe 82, and the piston 58 slides forward to operate the desk brake, and the brake is applied. Since the shaft 37 is braked and stopped, the front wheels are driven at double speed.

During that time, the shift fork 43 also moves rearward, but since there is a gap in the circumferential direction between the claw of the cylindrical body 86 and the claw of the boss 87, the control shaft is resisted against the winding spring 98.
Only 88 rotates, the cylinder 86 to which the arm 94 is fixed does not rotate, and the operation lever 95 is stopped at the front wheel speed-up standby position.

FIGS. 12 to 14 show another embodiment in which the detection mechanism is installed in the gear case 107, in which the lower portion 143 having a wide width L ₃ is provided on one side of the screw shaft 126 in the above embodiment, and the other. A prismatic slide member (slide piece) 145 having a lower portion 144 having a narrow width L ₄ on the side and a guide groove 146 provided on the lower surface is screwed, and is formed by a guide bolt screwed from the lower surface of the gear case 107. The regulating member 147 is inserted into the guide groove 146 so that the slide member 145 slides back and forth while maintaining a constant posture, and is inserted into the outer hole of the gear case 107 and screwed to the same as the above-described embodiment. The contact portion of the switch 137 is in contact with one of the lower portions 144, and the slide angle 145 can be changed back and forth and mounted to change the cutting angle detection timing to a slow speed. Even if this detection mechanism rotates the steering handle 103 and the output shaft 120 rotates in either direction, the front portion or the rear portion of the lower portion 143 or 144 is switched.
137 is turned on, whereby the solenoid valve 77a is turned on.

In FIG. 3, 114 is a normally-open speed increasing standby position center which is turned on when the operating lever 95 is set to the speed increasing standby position,
115 is a normally closed high-speed sensor that is turned off when the sub-shift lever is set to a high speed position, switch 137 is a normally open type, 116 is a solenoid valve 77a silenoid, and 117 is a monitor lamp.

(G) Effect of the Invention As described above, the present invention is an agricultural tractor in which a transmission is provided in the drive system of the front wheels, the transmission is detected by a front-wheel turning angle detection device, and switching is performed based on the detection result. There
A space formed by meshing the input shaft 106 and the output shaft 120, which are crossed in the steering transmission system, via a bevel gear 113, 119 attached to each shaft end so that the gear case 107 is capable of transmission and is meshed with the bevel gear 113, 119. In the section, both shafts 106,
A screw shaft 126, into which the slide members 127, (145) are screwed, is extended to one shaft end of the 120, and the slide members 127, (14
5) In the above space, a regulating member 147 that regulates the rotation of the slide members 127, (145) around the shaft center due to the rotation of the screw shaft 126, and the movement of the slide members 127, (145) in the axial direction. The detection switch for detecting the rotation angle of the front wheels is determined by the engagement of the bevel gears 113 and 119 because the detection mechanism that responds to the rotation of the shafts 106 and 120 is installed in the gear case 107. By effectively utilizing the space formed, it can be installed compactly in the gear case 107 with a simple structure, and the detection switch 137 that detects the front wheel cutting angle is a low-priced and simple structure of a simple switch. It is possible to accurately perform the detection operation while enabling the above, and by lubricating the inside of the gear box, the detection mechanism is also lubricated, and the desired detection operation can be maintained for a long period of time.

Further, since the detection mechanism is configured inside the gear case 107 without being exposed to the outside, muddy soil, muddy water, dust or the like does not adhere to and accumulate on the detection mechanism, and rainwater may be accumulated. Because it doesn't work,
It is possible to reliably prevent the durability from decreasing.

[Brief description of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a longitudinal sectional view of a front wheel speed increasing device, Fig. 2 is a transmission system diagram, Fig. 3 is a side view of an agricultural tractor, and Fig. 4 is A vertical plan view of essential parts,
5 is a perspective view of the front part of the shift rail, FIG. 6 is a cross-sectional view of the operation mode conversion device, FIG. 7 is a control circuit diagram, FIG. 8 is a side view of the steering device, and FIG. Fig. 10 is a longitudinal sectional view of the angle detecting device, Fig. 10 is a transverse sectional view of the same as above, Fig. 11 is a hydraulic circuit diagram, and 12
14 show another detection mechanism, FIG. 12 is a longitudinal sectional view thereof, FIG. 13 is a transverse sectional view thereof, and FIG. 14 is a plan sectional view thereof. 5 ... Intermediate case, 7 ... Main mission case, 17 ...
Clutch housing, 21 …… differential case, 25 …… holder, 37 …… brake shaft, 39 …… hub, 43 …… shift fork, 50 …… cylinder, 58 …… piston, 71 …… shift rail, 73 …… spool Department, 76 ... Refueling port, 77 ...
Control valve, 77a ... Solenoid valve, 78, 82 ... Pipe, 81 ... Discharge port, 95 ... Operating lever, 106 ... Shaft (input shaft), 107 ... Gear case, 113, 119 ... Bevel gear, 120 ... … Output shaft, 126… Screw shaft, 127… Sliding member, 130… Swing arm, 136… Pin, 137… Switch (detection switch), 145… Sliding member, 147…
… Regulation member

Claims (1)

[Claims] 1. An agricultural tractor in which a transmission is provided in a front wheel drive system, the transmission is detected by a front wheel turning angle detection device, and switching is performed according to the detection result, which is provided in a steering transmission system. The intersecting input shaft 106 and output shaft 120 are axially supported by a gear case 107 so that they can be meshed and transmitted via bevel gears 113 and 119 attached to the respective shaft ends, and in the space formed by the meshing of the bevel gears 113 and 119, the both Screw shaft 1 in which slide members 127, (145) are screwed onto one shaft end of shafts 106, 120
A restriction member 1 that extends 26 and that restricts the rotation of the slide members 127, (145) around the shaft center associated with the rotation of the screw shaft 126 in the space of the slide members 127, (145).
47 and a detection switch 137 for detecting the axial movement of the slide members 127, (145) provided in the gear case 107. The detection mechanism responsive to the rotation of the shafts 106, 120 has a gear case 107.
A corner angle detecting device for an agricultural tractor, which is configured to be installed inside.