JP4358997B2 - Work wheel front wheel turning angle detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, when the steering handle of a work vehicle such as a tractor is cut from a straight traveling position by a predetermined angle or more, the work implement is lifted to detect the rotation angle of the steering handle in a configuration in which the front wheels are driven at an increased speed. Department of technology.
[0002]
[Prior art]
During plowing work with a tractor, etc., when reaching the end of the field and moving to the next line, the steering handle is rotated from the straight line state at the end of the field in order to facilitate the lifting and lowering operation of the work equipment and to prevent roughening of the field. When turning operation is performed, a technique for raising the work implement (turning UP) and increasing the driving speed of the front wheels (front wheel acceleration) is known. The steering handle is rotated by switching a control valve connected to the steering rod to extend and retract the power steering cylinder to rotate the front wheels. In addition, a sensor shaft is attached to the cylinder rod of the power steering cylinder, and the movement of the sensor shaft is detected by a sensor or the like to detect the turning angle of the front wheel.
[0003]
[Problems to be solved by the invention]
In the prior art as described above, turning UP and front wheel acceleration are performed at the same time, and the cutting angle is detected by contacting one switch with the sensor shaft using the detection means as a switch, thereby reducing costs. However, when the steering handle is turned more than the set angle at the end of the field, the work equipment is raised and the front wheel speed is increased at the same time, and before the work equipment leaves the ground surface, it is switched to the front wheel speed. A sharp turn is made, and the end point of tillage is tilled diagonally and ends. In addition, since the work machine is lifted while being driven, there is a problem that the work machine is lifted while plowing with the rear of the work machine being opened, and the soil is splashed obliquely backward.
[0004]
[Means for Solving the Problems]
The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.
[0005]
According to claim 1, in a work vehicle in which when the steering handle (17) is cut from a straight traveling position by a predetermined angle or more, the work implement is lifted and the front wheels are driven to increase the speed, the steering handle (17) starts to be lifted. An angle and front wheel acceleration start angle detection unit (13) is provided in the steering device. The steering device is provided in the front axle case (11), the hydraulic cylinder (12) of the power steering device, and the support case (36). A stored sensor shaft (23) is arranged in parallel, and the detection unit (13) is supported by a single sensor shaft (23), the support case (36), and a turning UP switch (25) and a front wheel. The speed increasing switch (26) is composed of two sensors, and on the sensor shaft (23), the turning UP detection notch (21) and Two detection notches for detecting wheel speed increase (22) having different lengths are provided in the longitudinal direction of the sensor shaft (23), and the two wheel turning detection notches (21) and front wheel increase are provided. Each detection notch surface of the speed detection notch (22) is arranged in a V shape when viewed in the axial direction of the sensor shaft (23) .
[0006]
According to a second aspect of the present invention, in the front wheel cutting angle detecting device of the working vehicle according to the first aspect, the axial length (L1) of the turning UP detection notch (21) is the front wheel acceleration detection notch ( 22) is configured to be shorter than the axial length (L2), and both notches (21, 22) are configured to be symmetrical with respect to the center of the machine body. The front wheel acceleration operation starting angle is set smaller than that .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The problems and means to be solved by the present invention are as described above. Next, an embodiment of the present invention shown in the accompanying drawings will be described. FIG. 1 is a side view of a work vehicle equipped with the front wheel turning angle detection device of the present invention, FIG. 2 is a front unit plan view, FIG. 3 is a front unit side view, FIG. 4 is a front wheel turning angle detection device sectional view, and FIG. FIG. 6 is an enlarged side view of the detection unit, and FIG. 6 is a side view of the mission case.
[0008]
First, a schematic configuration of a tractor which is an embodiment provided with a front wheel turning angle detection device according to the present invention will be described. In FIG. 1, an engine 2 is mounted in a hood 1 at the front, and a cabin 3 in which a driver's seat on which an operator gets on, a steering handle 17, etc. is housed is provided at the rear of the hood 1, and the working machine is raised and lowered at the rear. A device 4 is arranged. A transmission case 5 is connected to the rear of the engine 2, and a rear wheel 6 is supported on both sides of the rear of the transmission case 5 via a rear axle case.
[0009]
Further, as shown in FIG. 6, a front wheel power take-out case 7 is provided at the lower part of the transmission case 5. Power is transmitted to the front axle case 11 via the transmission shaft 9 in front of the front wheel power take-out case 7, The front wheel 8 supported by the front axle case 11 is configured to be drivable. The front wheel power take-out case 7 houses a four-wheel drive clutch and a front wheel acceleration clutch, and an electromagnetic direction switching valve 31 is provided on the side of the front wheel power take-out case 7 so that both clutches can be switched. . A hydraulic case 41 and a hydraulic control device 42 are provided on the upper surface of the transmission case 5, and a piston is accommodated in the hydraulic case 41 so that the lift arm 40 protruding from the side surface of the hydraulic case 41 can be driven to rotate. . The hydraulic control device 42 is provided with a lifting motor 32, and the lifting control valve is switched by rotating a link or the like by driving the lifting motor 32.
[0010]
Next, the front unit 30 will be described with reference to FIGS. The front unit 30 constitutes a part of the steering device, and includes a front axle case 11, a hydraulic cylinder 12 of the power steering device, a tie rod 14, a rotating case 33 that rotatably supports the front wheel 8, and the like. . The front axle case 11 includes left and right cases 11R and 11L, and a center case 11M disposed therebetween, and rotating cases 33 and 33 are attached to both outer sides of the left and right cases 11R and 11L. The input shaft 34 protrudes rearward from the rear surface of the center case 11M and is connected to the transmission shaft 9 via a universal joint or the like (not shown). The power transmitted to the input shaft 34 is transmitted to the differential device in the front axle case 11. It can be transmitted to the front wheels 8 through the like. A center pin 35 projects forward from the left and right center of the front axle case 11 and is supported by the front frame so as to be swingable in the left and right direction.
[0011]
On the front surface of the center case 11M, a power steering hydraulic cylinder 12 is provided horizontally in the horizontal direction. The hydraulic cylinder 12 is a double rod type in which piston rods 12a and 12a protrude from both sides, and the tip of the piston rod 12a is connected to a tie rod 14 via a spherical joint 15. The other end of the tie rod 14 is a knuckle arm 16; It is connected to. The knuckle arm 16 is fixed to the side of the rotating case 33 that supports the front wheel 8, and by rotating the knuckle arm 16, the front wheel 8 can be rotated around the kingpin.
[0012]
A detection unit 13 is attached to the front surface of the center case 11M. The detection unit 13 includes a support case 36, a sensor shaft 23 housed in the support case 36, a turning UP switch 25 serving as a sensor, and a front wheel speed increasing switch 26. Mounting plates 29 and 29 are fixed to both ends of the sensor shaft 23, and the other ends of the mounting plates 29 and 29 are fixed to piston rods 12a and 12a of the hydraulic cylinder 12, and the sensor shaft 23 is installed horizontally in the horizontal direction. The sensor shaft 23 and the hydraulic cylinder 12 are configured to be parallel.
[0013]
As shown in FIGS. 2 and 5, the central portion of the sensor shaft 23 is slidably accommodated in the support case 36, and the retaining rings 37 and 37 are locked on the sensor shaft 23 in the support case 36. The springs 28 and 28 are externally fitted, and are urged by the springs 28 and 28 so that the sensor shaft 23 is positioned substantially at the center. Further, a turning UP detection notch 21 and a front wheel acceleration detection notch 22 are respectively provided on the outer periphery of the central portion of the sensor shaft 23. The turning UP detection notch 21 and the front wheel acceleration detection notch 22 are shown in FIG. As shown in FIG. 4, the detection surface is cut in the longitudinal direction so as to be parallel to the tangent line, and the surface formed by the turning UP detection notch 21 and the front wheel acceleration detection notch 22 is substantially V-shaped. ing. Then, as shown in FIG. 5, the axial length L1 of the turning UP detection notch 21 is shorter than the axial length L2 of the front wheel acceleration detection notch 22 (L1 <L2). It is comprised so that it may become left-right symmetric with respect to the body center.
[0014]
Then, as shown in FIG. 4, from the outside of the support case 36 toward the left and right central portions of the turning UP detection notch 21 and the front wheel acceleration detection notch 22, that is, toward the substantial axis of the sensor shaft 23. Thus, the mounting holes 36a and 36b are formed and communicated with the inside of the support case 36 so that the surfaces forming the centers of the mounting holes 36a and 36b are perpendicular to the axial direction of the sensor shaft 23. I have to. Thus, the turning UP switch 25 and the front wheel speed increasing switch 26 are arranged in a compact manner. After one or more balls 27 and 27 are inserted into the mounting holes 36a and 36b, the turning UP switch 25 and the front wheel acceleration switch 26 are attached, and the turning UP detection notch 21 and the front wheel acceleration detection notch are installed. 22 are arranged so that the balls 27 and 27 come into contact with each other, and the detection units of the turning UP switch 25 and the front wheel acceleration switch 26 come into contact with the balls 27 and 27, respectively. However, it is also possible to adopt a configuration in which the detection unit of the switch is extended without providing the ball 27 and is directly detected.
[0015]
In such a configuration, when the ball 27 enters the turning UP detection notch 21, the turning UP switch 25 is turned off, and when the ball is pushed out from the turning UP detection notch 21, the detection unit of the turning UP switch 25 is activated. Pressed to turn on. Similarly, the front wheel acceleration switch 26 is OFF when a ball is in the front wheel acceleration detection notch 22.
[0016]
When the sensor shaft 23 is slid by the rotation of the steering handle 17 and the ball 27 comes out of the turning UP detection notch 21, the turning UP switch 25 is turned on to raise the work implement. The position of the notch 21 end coincides with the time when the steering handle 17 is rotated by the first set angle, and becomes the rising operation start angle. When the ball 27 comes out of the front wheel acceleration detection notch 22, the front wheel acceleration switch 26 is turned on and the front wheel acceleration is activated. The position of the front wheel acceleration detection notch 22 is located at the second position of the steering handle 17. This coincides with the time when the set angle is rotated and becomes the front wheel acceleration operation start angle. The first set angle and the second set angle can be detected by providing an angle sensor on the handle shaft, but the angle sensor is more expensive than the switch and also requires a control circuit. This increases costs.
[0017]
In the configuration as described above, since the steering handle 17 is not cut during the straight-ahead operation, the balls 27 and 27 remain in the notch 21 for turning UP detection and the notch 22 for detecting front wheel acceleration, The turning UP switch 25 and the front wheel acceleration switch 26 are OFF. When turning to the farm field end, the steering handle 17 is rotated to operate the hydraulic cylinder 12, and when the turning angle exceeds the first set angle, the piston rod 12 is expanded and contracted via the sensor plate 29. Then, the sensor shaft 23 is slid, and the ball 27 is first pushed out from the short turning detection notch 21 for turning, and the turning UP switch 25 is turned on to drive the elevating motor 32 to switch the control valve. The work implement lifting device 4 is raised. At this time, the turning angle of the steering handle 17 is small, and the aircraft is still in a substantially straight state.
[0018]
When the switch handle 17 is further rotated to reach the second set angle or more, the ball 27 is pushed out from the front wheel acceleration detection cutout 22 which is a long cutout, the front wheel acceleration switch 26 is turned on, and the front wheel drive is taken out. The electromagnetic direction switching valve 31 attached to the side surface of the case 7 is switched, and the front wheel acceleration clutch is operated to drive the front wheels at an increased speed. At this time, the work machine is lifted and the front wheel is accelerated, so that the machine body is in a sharp turn state.
[0019]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0021]
In a working vehicle in which the work implement is lifted and the front wheels are driven at a higher speed when the steering handle (17) is turned by a predetermined angle or more from the straight traveling position, the steering handle (17) is lifted. An operation start angle and front wheel acceleration operation start angle detection unit (13) is provided in the steering device. The steering device includes a front axle case (11), a hydraulic cylinder (12) of the power steering device, and a support case (36). The sensor shaft (23) housed in the) is arranged in parallel, and the detection unit (13) is supported by a single sensor shaft (23) and the support case (36). And the front wheel speed increasing switch (26), and the turning UP detection notch (21) on the sensor shaft (23). Two detection cutouts with different lengths of the front wheel acceleration detection cutout (22) are provided in the longitudinal direction of the sensor shaft (23), and the two turning UP detection cutouts (21) and the front wheel increase are provided. Since each detection cut-out surface of the speed detection cut-out (22) is arranged in a V-shape when viewed in the axial direction of the sensor shaft (23), the structure of the detection unit can be configured simply and compactly. Can be centrally arranged, and the switch can be arranged upward to prevent damage.
[0020]
According to a second aspect of the present invention, in the front wheel cutting angle detection device for the working vehicle according to the first aspect, the axial length (L1) of the turning UP detection notch (21) is the front wheel acceleration detection notch. The length (L2) in the axial direction of (22) is shorter, and further, the notches (21, 22) are configured to be symmetrical with respect to the center of the machine body, and the lifting operation start angle of the work machine Is set to be smaller than the front wheel acceleration start angle, so if the steering handle is turned when opening at the end of the field, the work equipment will first rise before the machine enters the turning motion, and the steering handle will be turned further. The front wheel is turned to the turning angle, the front wheel acceleration is activated after the aircraft is turned in the turning direction, the end point of the tillage is not inclined, it can be processed cleanly without damaging the headland, and the rotary rotates Even if it rises, the tillable soil is inclined Never skip it.
[Brief description of the drawings]
FIG. 1 is a side view of a work vehicle equipped with a front wheel turning angle detection device of the present invention.
FIG. 2 is a top view of a front unit.
FIG. 3 is a side view of the front unit.
FIG. 4 is a cross-sectional view of a front wheel turning angle detection device.
FIG. 5 is an enlarged cross-sectional view of a detection unit.
FIG. 6 is a side view of a mission case.
[Explanation of symbols]
12 Hydraulic cylinder 21 Notch for turning UP detection 22 Notch for detecting front wheel acceleration 23 Sensor shaft 25 Turning UP switch 26 Front wheel acceleration switch

Claims (2)

When the steering handle (17) is cut from the straight traveling position by a set angle or more, the working machine is raised and the front wheel is driven to increase the driving speed. A start angle detector (13) is provided in the steering device. The steering device includes a front axle case (11), a hydraulic cylinder (12) of the power steering device, and a sensor shaft ( 23) are arranged in parallel, and the detection part (13) is supported by a single sensor shaft (23), the support case (36), and a turning UP switch (25) and a front wheel acceleration switch (26). The turning UP detection notch (21) and the front wheel acceleration detection notch (21) are formed on the sensor shaft (23). 2) Notches for detection at two locations of different lengths are provided in the longitudinal direction of the sensor shaft (23), and the notches for detection of turning UP (21) and the front wheel acceleration detection notches (22) at the two locations. The detection angle detection device for a front wheel of a work vehicle , wherein each of the detection cut-out surfaces is arranged in a V shape when viewed in the axial direction of the sensor shaft (23) . The front wheel cutting angle detection device for a work vehicle according to claim 1, wherein a length (L1) of the turning UP detection notch (21) in an axial direction is an axial direction of the front wheel acceleration detection notch (22). The two notches (21, 22) are configured to be bilaterally symmetrical with respect to the center of the machine body, and the ascending operation start angle of the work machine is set to start the front wheel acceleration operation. A front wheel turning angle detection device for a work vehicle, characterized in that it is set smaller than an angle .

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