JPH08811Y2 - Lifting position detection device for hydraulic equipment for lifting work equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a lifting position detecting device for a hydraulic device for lifting a working machine in a tractor.

(Prior Art) A tractor is equipped with a working machine lifting hydraulic device having a pair of left and right lift arms that can be raised and lowered around a hydraulic arm axis in a rear part of a vehicle body, and a working machine mounted on the rear of the vehicle is lifted and lowered by a lift arm. I am going to raise and lower by.

When an electric control system is used for position control or draft control in this type of tractor, it is necessary to electrically detect the lifted position of the lift arm, that is, the lifted position of the working machine. It is considered to detect using a position detector.

As concrete means thereof, for example, a structure in which the hydraulic arm shaft and the detector are arranged so as to face each other on the axial center and the rotation shaft of the detector is engaged with the hydraulic arm shaft, or a position separated from the hydraulic arm shaft There is a structure in which the detector is arranged in advance and the hydraulic arm shaft and the rotating arm of the detector are interlocked via a link mechanism.

(Problems to be solved by the invention) However, in the former case, if there is a slight misalignment between the hydraulic arm shaft and the rotating shaft of the detector, it will be a burden on the detector and There is a fear of shortening the life.

Further, in the latter case, a link mechanism is required, which has a drawback of increasing the manufacturing cost.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a position detection device having excellent durability, low manufacturing cost, and excellent workability during assembly.

(Means for Solving the Problems) As a means for solving the problems, the present invention includes a working machine lifting hydraulic device 5 having a lift arm 11 that can be lifted and lowered around an arm shaft 10, and a lifter 11 is provided around the arm shaft 10. In a rotation type position detector 28 that detects the amount of lift of the lift arm 11 based on the amount of rotation of the rotating shaft 27 that rotates in conjunction with the lifting operation, the rotating shaft 27 of the arm shaft 10 is The position detector 28 is attached and fixed to the fixed side of the hydraulic device 5 so as to be substantially coincident with the axis, and the rotary arm 32 is provided on the rotary shaft 27 so as to project in the radial direction. The rotating arm 32 is provided with a pin 26 slidably abutting in the radial direction of the rotating shaft 27 so that the rotating shaft 27 is rotated in association with the raising and lowering of the arm shaft 10 of 11. Equipped with urging means 33 for urging the rotating arm 32 so that the moving arm 32 always contacts the pin 26. It is those who are.

(Operation) Since the pin 26 and the rotating arm 32 are in the engaged state, when the lift arm 11 moves up and down, the rotating shaft 27 of the position detector 28 rotates via the rotating arm 32, and the detector 28 operates to detect the lifted position of the lift arm 11. At this time, since the pin 26 and the rotating arm 32 are slidable in the arm longitudinal direction,
Even if there is a slight misalignment between the arm shaft 10 and the rotating shaft 27, it does not burden the detector 28.

(Embodiment) Hereinafter, the present invention will be described in detail with reference to the illustrated embodiment. In FIG. 3, 1 is a tractor body, 2 is a rear wheel, 3 is a rear wheel fender, and 4 is a driver's seat. Reference numeral 5 denotes a hydraulic device for raising and lowering the working machine, which comprises a hydraulic device main body 6, a piston 7, a piston rod 8, a hydraulic arm 9, an arm shaft 10, a lift arm 11 and the like. The hydraulic device 5 is a rear portion of the tractor body 1. It is installed in.

A rotary device 12 is provided with a machine frame 13, a plowing claw 14, a rotary cover 15, and the like, and is attached to the rear of the tractor body 1 via a three-point link mechanism 18 including a top ring 16 and a pair of left and right lower links 17. There is. The lower link 17 is connected to the lift arm 11 via a lift rod 19. Therefore, the rotary device 12 includes the hydraulic arm shaft 10 of the lift arm 11.
It can be raised and lowered freely by moving up and down.

The arm shaft 10 is rotatably supported by a pair of left and right bearing portions 20 of the hydraulic device main body 6 as shown in FIGS. 1 and 2, and is attached to the spline portions 21 at both left and right ends of the arm shaft 10. A pair of left and right lift arms 11 are fitted and are retained by a retaining plate 22. The retaining plate 22 has a disc shape,
It is fixed by a bolt 24 screwed into a screw hole 23 formed at the axial center position of the arm shaft 10 and a pin 26 engaged with an engagement hole 25 formed at an eccentric position. The pin 26 penetrates the retaining plate 22 and projects outward, and is fixed to the retaining plate 22 by welding.

A rotation type position detector 28 is arranged outside one end of the arm shaft 10 so that the axis of the rotation shaft 27 substantially coincides with that of the arm shaft 10. This detector 28 consists of a volume,
The resistance value is proportionally changed by the rotation of the rotation shaft 27, and the lifted position of the lift arm 11 is electrically output. The detector 28 is fixed to the inner side surface of a mounting plate 29, and the mounting plate 29 is fixed to the hydraulic device body 6 via a spacer 30, bolts 31 and the like. A rotary arm 32 is fixed to the rotary shaft 27, and the rotary arm 32 is a pin on the lift arm 11 side.
It is slidably engaged with 26 from above, and is urged by a tension spring (biasing means) 33 in the engaging direction, that is, downward. It should be noted that one end of the spring 33 is hooked on a spring hook portion on the lower side of the mounting plate 29. Therefore, if the lift arm 11 moves up and down around the arm shaft 10, the pin 26 and the rotation arm are moved.
A detector 28 can be operated in conjunction with the lift arm 11 via a rotating shaft 27 and 32.

FIG. 4 shows a position control circuit, 34 is a position setter for setting the position of the rotary device 12, 35 is a comparator, which compares the set position of the setter 34 with the detected position of the detector 28, Are configured to output an up or down command to the ascending solenoid 37 or the descending solenoid 38 of the position control valve 36 for the hydraulic device 5.

In position control, if the setting device 34 sets a proper position, the comparator 35 operates and compares the detected position from the detector 28 with the set value. Then, the control valve 36 is operated by the output of the comparator 36 so that the two positions coincide with each other, and the lift arm 11 of the hydraulic device 5 moves up and down around the arm shaft 10.

The lift arm 11 is, for example, in the ascending direction (shown by the arrow A in FIG. 2).
When it is turned to, the turning shaft 27 is turned integrally via the turning arm 32 that engages with the pin 26, and the detector 28 moves to the lift arm 11.
The rising position of is detected. In this case, the rotating arm 32
Since it is only slidably engaged with 26 from the upper side, even if there is some misalignment between the arm shaft 10 and the rotary shaft 27, it will be a burden on the detector 28 and the life will be shortened. Does not cause a decrease in Further, since they are simply engaged with each other, the structure is simple, the manufacturing cost is low, and the workability during assembly is good.

Also in the case of FIGS. 1 and 2, a torsion spring may be incorporated in the rotating shaft 27 instead of the tension spring.

The detector 28 may be a pulse encoder or the like in addition to the volume.

(Effects of the Invention) According to the present invention, the working machine lifting hydraulic device 5 having the lift arm 11 which can be lifted up and down around the arm shaft 10 is provided, and the lifting arm 11 rotates in association with the lifting motion around the arm shaft 10. A rotary type position detector 28 that detects the amount of elevation of the lift arm 11 by the amount of rotation of the rotating shaft 27 that moves is provided so that the rotating shaft 27 substantially coincides with the axis of the arm shaft 10. The position detector 28 is fixedly mounted on the fixed side of the hydraulic device 5, and the rotary shaft 27 is provided with a rotary arm 32 in a radially protruding shape.
The lift arm 11 side is slidably contacted to the rotary arm 32 in the radial direction of the rotary shaft 27 so that the rotary shaft 27 rotates in conjunction with the elevation of the lift arm 11 around the arm shaft 10. Between the arm shaft 10 and the rotary shaft 27, since the rotary arm 32 is provided with a biasing means 33 for biasing the rotary arm 32 so that the rotary arm 32 always contacts the pin 26. Even if there is some misalignment, the position detector 28 is not burdened with it and is excellent in durability. Moreover, the structure is simple, the manufacturing cost is low, and the workability during assembly is good. Further, in the present invention, in particular, the pin 26 that slidably contacts the rotary arm 32 provided on the rotary shaft 27 of the rotary position detector 28 in the radial direction of the rotary shaft 27 is attached to the lift arm. Provided on 11, and also a rotating arm 32
Is provided with a biasing means 33 for biasing the rotating arm 32 so as to always contact the pin 26, the rotating arm 32 contacts the pin 26 without rattling and rotates with respect to the pin 26. arm
With a structure in which the up-and-down position of the lift arm 11 can be detected with good followability of the 32, the pin 26 can be brought into contact with the rotating arm 32, and the contact state can be maintained by the biasing means 33. Therefore, when producing the rotary arm 32, it is possible to easily produce the rotary arm 32 without much consideration.

[Brief description of drawings]

1 to 4 exemplify a first embodiment of the present invention, in which FIG. 1 is a fragmentary plan view of a main portion, FIG. 2 is a side view of the same, and FIG. 3 is an overall side view. 4 is a control circuit diagram. DESCRIPTION OF SYMBOLS 1 ... Tractor body, 5 ... Hydraulic device for lifting work equipment, 6 ... Hydraulic device body, 10 ... Arm shaft, 11 ... Lift arm, 22 ... Retaining plate, 26 ... Pin, 27 ... Rotating shaft, 28 ... Position detection Bowl, 32 ...
Pivoting arm.

Claims (1)

[Scope of utility model registration request] 1. A lift arm that can move up and down about an arm shaft 10.
A work machine lifting hydraulic device 5 having 11 is provided, and rotation for detecting the amount of lift of the lift arm 11 by the amount of rotation of a rotary shaft 27 that rotates in conjunction with the lifting operation of the lift arm 11 around the arm shaft 10. In which the position detector 28 is attached and fixed to the fixed side of the hydraulic device 5 so that the rotating shaft 27 substantially coincides with the axis of the arm shaft 10. The rotating arm 32 is provided on the 27 in a radially projecting manner, and the rotating arm 27 is rotated on the side of the lift arm 11 so that the rotating shaft 27 rotates in association with the elevation of the lift arm 11 around the arm shaft 10.
32 is provided with a pin 26 slidably abutting in the radial direction of the turning shaft 27, and a biasing means 33 for biasing the turning arm 32 so that the turning arm 32 always abuts the pin 26. A lifting position detecting device for a hydraulic device for lifting a working machine, which is characterized by being provided.