JP2514731Y2 - Tilt control device for working section of tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a tilt control device for a working unit of a tractor.

[Problems to be Solved by Prior Art and Invention] Generally, in this type of tractor, a working unit is formed by expanding and contracting a lift cylinder (expandable cylinder) that connects a lift arm on the machine side and a lower link of a lifting link mechanism. In order to control the left and right tilt of the lift cylinder, a stroke sensor is provided in the lift cylinder to feed the working length of the lift cylinder to the tilt control section, and in the past, it was slidable between the cylindrical cylinder and the inner circumference of the cylinder. An electric resistance type stroke sensor has been used, which is composed of a rod installed inside the vehicle and a detection unit that detects an electric resistance that changes as the rod slides.

However, in the electric resistance type stroke sensor, a detection error occurs when the rod rotates in the cylinder, and therefore, the detection accuracy decreases when the stroke sensor is twisted together with the lift cylinder due to the characteristics of the lifting link mechanism. In addition, there is a drawback that durability is inferior due to severe wear caused by sliding of the rod.

Therefore, it is proposed to use a capacitance type sensor that is small in size and has excellent durability as a stroke sensor that is hardly affected by twisting. Therefore, the further problem of having to consider interference with other members must be solved.

[Means for Solving the Problems] The present invention was devised with the object of providing an inclination control device for a working part of a tractor capable of eliminating these drawbacks in view of the above circumstances. , One of left and right lift rods connecting a lift arm for raising and lowering drive and a lower link of a raising and lowering link mechanism is composed of a telescopic cylinder, and telescopic control of the telescopic cylinder based on a detection length of a stroke sensor provided in the telescopic cylinder In a tractor provided with an inclination control section for controlling the left and right inclination of a working section connected to a lifting link mechanism by means of the stroke sensor, the stroke sensor is used to change the operating length of the lift cylinder based on a change in electrostatic capacitance accompanying the operation of the lift cylinder. It is a capacitance type that detects, and its detection part is projected on the outer peripheral surface of the cylinder part of the stroke sensor. The stroke sensor is mounted on the rear upper surface side of the telescopic cylinder, and the detection portion is mounted in a posture protruding in the left-right direction from the stroke sensor.

With this configuration, the present invention can improve the detection accuracy in detecting the working length of the telescopic cylinder and the durability of the detection device.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.
In the drawings, 1 is a traveling vehicle of an agricultural tractor,
A rotary tillage type working unit 5 is connected to a rear portion of the traveling machine body 1 via a three-point link mechanism 4 including a single top link 2 and a pair of left and right lower links 3, and the working unit 5 Is lifted up and down by vertically swinging a lift arm 8 which suspends the left and right lower links 3 via a lift rod 6 and a lift cylinder 7, respectively, and tilts left and right by a hydraulic expansion and contraction operation of the lift cylinder 7. All of the configurations are conventional.

Reference numeral 9 denotes a stroke sensor for detecting the extension / contraction length of the lift cylinder 7. The stroke sensor 9 feeds a length signal of the lift cylinder 7 to a control unit 10 for controlling the extension / contraction operation of the lift cylinder 7. However, this is composed of an electrostatic capacitance type stroke sensor which detects the length based on the electrostatic capacitance change. That is, the stroke sensor 9 inserts the rod 9b in a non-contact manner into the inner peripheral portion of the cylindrical cylinder 9a, and
On the outer peripheral portion of, the detection unit 9c that detects the electrostatic capacitance between the cylinder 9a and the rod 9b and outputs a DC voltage according to the change is configured to project. Since it detects the capacitance, it is small in size and is provided on the upper end side of the outer peripheral portion of the cylinder 9a. As shown in FIGS. 1 to 3, the stroke sensor 9 is attached to the rear upper surface side of the telescopic cylinder 7 and the detection portion 9c protruding leftward so as to overlap the cylinder tube 7a in a rear view. ing. That is, the cylinder 9a is connected to the pin 10 protruding from the cylinder portion 7a of the lift cylinder 7, while the rod 9b is connected to the pin 11 protruding from the rod portion 7b of the lift cylinder 7, so that In this state, the detecting portion 9c protrudes to the left and right sides, but is arranged so as to overlap the cylinder tube 7a in a rear view.

On the other hand, reference numeral 12 denotes an inclination sensor for detecting the left-right inclination of the traveling body 1, and the inclination sensor 12 is
The left and right are the left and right fan 1a, and the upper and lower are the fuel tanks 13
It is provided at a substantially central position of the traveling machine body 1 surrounded by the hydraulic case 14. That is, the inclination sensor 12 is disposed above the hydraulic case 14 that houses the hydraulic operating mechanism of the lift arm 8 and is protected by the surrounding member.
Mount the mounting plate 15 of the tilt sensor 12
It is fixed to the hydraulic case 14 by tightening together with 16 fixing bolts 17.

Furthermore, reference numeral 18 denotes a rear cover provided on the rear part of the working unit 5 so as to be vertically swingable. The rear cover 18 is supported by a main cover 19 so as to be movable back and forth, and is controlled to move back and forth by driving an electric cylinder 20. The stroke sensor 21 for detecting the length, which is arranged in parallel with the electric cylinder 20, is also of the same capacitance type as the stroke sensor 9.

In the embodiment of the present invention configured as described above, the stroke sensor 9 detects an electrostatic capacitance that changes due to expansion and contraction associated with the operation of the lift cylinder 7, and outputs a DC voltage corresponding thereto to the control unit 10. However, even if the rod 9b rotates due to a twisting force when the stroke sensor 9 expands or contracts, no detection error occurs in the capacitance type stroke sensor 9. Therefore, it is possible to perform extremely accurate tilt control of the working unit based on the detection of the lift cylinder 7 length without error.

Moreover, the capacitance type stroke sensor 9 is a cylinder
Since this is a non-contact type sensor in which the 9a and the rod 9b are not in contact with each other, wear of parts can be prevented and durability can be improved.

Further, in the electrostatic capacitance type stroke sensor 9, the detection unit 9c can be made smaller than that of the electric resistance type, but the detection unit 9c further protrudes to the left or right of the stroke sensor 9, In addition, since it is attached to the cylinder cylinder 7a in a state of overlapping with the rear view, the stroke sensor 9 including the detecting portion 9c is arranged on the rear upper surface side of the telescopic cylinder 7, and the front lower part is blocked by the telescopic cylinder 7. Therefore, the stroke sensor 9 and its detecting portion 9c are protected by the fact that the mud and the like splashed up by the wheels hit the telescopic cylinder 7. Besides,
Since the stroke sensor 9 is attached in such a manner that the detecting portion 9c projects to one side in the left-right direction, the stroke sensor 9
Can contribute to the improvement of the detection accuracy because the detection unit 9c can be placed in the mounting posture close to the telescopic cylinder 7 without protruding rearward, and the protruding detection unit 9c can be prevented from contacting the rear member. The consideration of may be the same as that of the stroke sensor.

Further, the capacitance type stroke sensor 9 has a simpler structure than that of the electric resistance type, so that the water resistance can be improved by simplifying the shape.

[Advantages] In summary, since the present invention is configured as described above, the left and right inclination control of the working unit is performed by the extension / contraction control of the extension / contraction cylinder based on the detection length of the stroke sensor provided in the extension / contraction cylinder. However, since the stroke sensor is a non-contact type and is a capacitance type in which a detection error does not occur due to twisting, even if a twisting force acts on the stroke sensor due to the characteristics of the lifting link mechanism, the cylinder length is It is suitable for performing accurate inclination control of the working unit that can perform accurate detection.

In addition, the stroke sensor is arranged on the rear upper surface side of the telescopic cylinder, and the front lower part is blocked by the telescopic cylinder, so that the mud, etc. splashed up by the wheels etc. hits the telescopic cylinder. This protects the stroke sensor and its detecting portion. In addition, since the stroke sensor is mounted in a posture in which the detection unit projects in the left-right direction, the stroke sensor can be mounted in a posture close to the telescopic cylinder without the detection unit protruding rearward, which improves detection accuracy. In addition to contributing to the improvement, consideration of avoiding contact of the protruding detecting portion with the rear member can be made similar to that of the stroke sensor.

[Brief description of drawings]

1 is a side view of a tractor according to the present invention, FIG. 1 is a side view of the tractor, and FIG. 2 is a rear view of a lift cylinder showing a mounting state of a stroke sensor. 3 and 4 are a side view of the same, FIG. 4 is a sectional view of a stroke sensor, FIG. 5 is a side view of a main part of a traveling machine body, and FIG. 6 is a rear view of a stroke sensor showing a conventional example. In the figure, 1 is a traveling machine body, 4 is a lifting link mechanism, 5 is a working unit, 7 is a lift cylinder, 9 is a stroke sensor, 9a is a cylinder, 9b is a rod, and 9c is a detection unit.

Claims (1)

(57) [Scope of utility model registration request] Claim: What is claimed is: 1. One of the left and right lift rods that connects the lift arm for driving up and down and the lower link of the lifting link mechanism is composed of a telescopic cylinder, and telescopic based on the detection length of a stroke sensor provided in the telescopic cylinder. In a tractor provided with a tilt control section for controlling left and right tilt of a working section connected to a lifting link mechanism by controlling expansion and contraction of the cylinder, the stroke sensor is provided on the basis of a capacitance change associated with the operation of the lift cylinder. It is assumed that it is a capacitance type that detects the working length of the stroke sensor, and that its detection part is projected on the outer peripheral surface of the cylinder part of the stroke sensor. An inclination control device for a working portion of a tractor, which is mounted so as to project from the sensor in the left-right direction