JP2716568B2 - Work tractor lifting mechanism for agricultural tractors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a device for mounting the working machine of an agricultural tractor.

(B) Prior Art A technique is known in which a working machine such as a mower attached to the working machine mounting device of a tractor can be moved up and down in a grounded state.

For example, as disclosed in JP-A-62-33232.

(C) Problems to be Solved by the Invention The present invention relates to a technique relating to a work machine lifting mechanism of a tractor with a low vehicle height, which is used by attaching a mower device to a lawn mowing operation on turf.

In order to perform lawn mowing work, it is necessary to be able to travel on an incline, and it is configured with a low center of gravity and a low vehicle height. However, when the tractor is provided with the mower device, the tractor has a low vehicle height, so that it is difficult to take a stroke when the mower device is raised by the work implement elevating device.

Also, when mowing, it is necessary to be able to move up and down to a certain extent by grounding on the grass surface in a floating state,
Floating is required in the grounded state, and it is required to be able to rise greatly in the ascended state.

Also, if the mower device mounted on the front part is moved up and down rapidly, the body will be impacted when the mower device suddenly touches the ground, causing problems such as the operator being thrown forward.

Therefore, in the present invention, only a part of the pressure oil discharged from the hydraulic pump is supplied to the front working machine elevating device, so that rapid elevating operation cannot be performed.

In the case of a mower device attached to the rear work machine elevating device,
Because it is the direction of towing, even if it touches down suddenly, it will not be a big impact.

(D) 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.

"Inverted U" -shaped frame 80 is pivotally supported at the tip of the top link 85 of the tractor, and a vertical link is provided in the middle of the top link 85.
The upper end of a center engagement arm 94 pivotally supported at the upper end of the upper and lower links 84 and the lower end of the upper and lower links 84 is fixed to an installation shaft 98 which is installed between the left and right sides of the "reverse U" -shaped frame 80. Outer engagement arms 96 that rotate integrally with the arm 94 are provided at the left and right ends of the erection shaft 98, and floating rods 81, 81 are provided at the ends of the erection shaft 98.
The middle of the floating rods 81, 81 are pivotally supported at the lower left and right ends of the floating rods 81, 81. The outer engaging arms 86, 96 provided on the outer engaging arms 96, 96 can be contacted from below, and the distal ends of the floating rods 81, 81 pivotally support the distal end of the mower device MF. Via a chain 89, it is configured to be suspended at the tip of a suspension arm 82 rotatably mounted between the "reverse U" -shaped frame 80 and the upper and lower links 84, and when the mower device MF is grounded,
When the contact between the floating rods 81 and the outer engagement pieces 86 is released, the vertical movement of the mower device MF is enabled.

Further, when the work machine is raised, the outer engaging pieces 86, 86 and the floating rods 81, 81 engage with each other, and the outer engaging pieces 86, 86 rotate downward, thereby lowering the rising angle of the mower device MF. This is larger than the lower link 36 ascending angle.

In addition, the pressure oil supplied to the front work machine elevating valve that controls the elevation of the front mower device MF is smaller than the pressure oil supplied to the rear hydraulic elevating device, and a flow valve CV is interposed to branch off preferentially. It was done.

(E) Embodiment The problems to be solved and means to be solved by the present invention are as described above. Next, the configuration of the embodiment shown in the attached drawings will be described.

1 is an overall side view of the agricultural tractor of the present invention, FIG. 2 is a plan view of the same with safety frames 26 and 27 and a canopy 29 removed, FIG. 3 is a plan view of a state with a body cover C removed, FIG. 4 is a plan view showing a state in which a mower device is disposed in front of or behind the tractor and on the side, FIG. 5 is a perspective view of the front work machine mounting device of the present invention, FIG. FIG. 7 is a front sectional view of a part of the same, and FIG. 8 is a hydraulic circuit diagram of the working machine elevating mechanism.

The body support member of the inclined tractor according to the present invention comprises a transmission clutch case A, a transmission case B, and a rear axle case RC as a “Γ” -shaped power transmission case, and a front portion of the “Γ” -shaped power transmission case. The engine E is attached to the left and right protruding portions in a cantilever state. A radiator R is attached to the rear surface of the engine E.

 This will be described with reference to FIGS. 1 and 2.

The aircraft is supported by front wheels 10L and 10R and rear wheels 11L and 11R.

A power transmission case constituting a body support member is disposed at the center of the body. The right side from the center of the fuselage is higher, and an engine E and a radiator R are arranged.

A steering handle 28, a seat S, and a battery 7 below the seat S are provided on the left side in the traveling direction of the aircraft.
Is arranged.

Below the steering handle 28 and the seat S, the battery 7, a power transmission case having a “Γ” shape, the engine E, and the vehicle body cover C that covers the radiator R are covered.

In the vehicle body cover C, the portion of the engine covering portion C1 that covers the side of the engine E is high, and conversely, the step / seat covering portion C2 that covers the seat S and the step portion is low. The position above the power transmission case between the engine cover C1 and the step / seat cover C2 is also low.

As shown in FIG. 1, the front and rear PTO clutch levers 71, the main speed change lever 32, and the front wheel drive clutch lever 72
, A sub-shift lever 78 and a hydraulic lift lever 73, and the upper ends of these levers are located at the engine cover C1.
It is configured lower than the upper surface of the tree so that it does not catch on the branches of the fruit tree.

A front grill M is protrudingly provided at the tip end of the vehicle body cover C.

As shown in FIG. 1, at the front of the body, a front work machine mounting device is constituted by a top link 35 and lower links 36, 36.
The lower link 36, 36 is moved up and down via 41.

In addition, the front PTO shaft 3
1 is being driven.

The front work machine mounting device includes a bracket protruding left and right.
It is composed between 34 and 34.

Also, a rear working machine mounting device is configured behind the body. The rear three-point link device includes a top link 38 and lower links 39. The lower link 39 is vertically rotated by the lift arm 24 via the lift link 40.

The rear PTO shaft projects rearward from the rear axle case RC.

A body frame 9 disposed at the front is disposed below a speed change clutch case A constituting a power transmission case having a “Γ” shape, and inclined support columns 21L are provided at left and right ends of the body frame 9.
A safety frame 27 is mounted and fixed on the upper ends of the inclined support columns 21L and 21R. Similarly, inclined support columns 22L and 22R are erected on the rear axle housings H and H that protrude left and right from the rear axle case CR, and a safety frame 26 is erected on the upper ends of the inclined support columns 22L and 22R. ing.

A right side frame 76 and a left step frame 44 are disposed between the front body frame 9 and the rear rear axle housing H. Is composed.

A canopy 29 is arranged on the four safety frames 26 and 27 to form a safety frame as a whole.

The steering valve 16 is disposed inside the front grille M in front of the steering handle 28. Reference numeral 30 denotes a steering column that supports the steering handle 28.

An air cleaner 14 is arranged in a space above the engine E in front of the engine E.

The oil pan 6 is a member attached below the engine E, and protrudes below a step frame 44 for mounting and supporting a step portion of the vehicle body cover C as shown in FIG. The oil pan 6 is disposed so as to be deviated rightward from the center between the left and right wheels.

Since the engine E is arranged on the right side of the power transmission case of the “Γ” shape, a seat S is provided on the left side, and an operator is placed, and the battery 7 is placed below the seat S. Is balanced.

FIG. 3 illustrates a state in which the vehicle body cover C is removed. The front wheel drive shaft 17 projects forward from the rear axle case RC, and transmits power to the front differential case FD. A rear PTO drive shaft 43 extends rearward from the transmission clutch case A to the rear PTO shaft 23.

The step frame 44 is disposed between the support frame 42 projecting laterally from the rear axle case RC and the vehicle body frame 9 in the front and rear directions.

Front frames 18 and 19 project forward from the left and right sides of the transmission clutch case A. Since the transmission clutch case A is deviated to the left from the center of the fuselage, the left front frame 19 projects straight forward, while the right front frame 18 is bent in the middle. Have been. A front weight locking body 13 is fixedly provided in front of the front frames 18 and 19.

Brackets 34 on the left and right sides of the front frames 18 and 19
34 is attached to the front work equipment mounting device.

A front PTO shaft 31 is arranged at the front of the aircraft, and a rear PTO shaft 23 is arranged at the rear of the aircraft.

A radiator R is disposed at the rear of the engine E, and a radiator fan F is disposed at the front of the radiator R. Also, in the rear of the radiator R, a dust net basket
12 are located.

 Next, the hydraulic circuit will be described with reference to FIG.

The hydraulic oil is discharged from the hydraulic pump P attached to the engine E, but since there is only one hydraulic pump P, it is necessary to branch the hydraulic oil into the rear working machine elevating device and the front working machine elevating device. .

The pressure oil discharged from the hydraulic pump P passes through the oil passage e and enters the flow valve CV from the oil passage f. The flow valve CV is branched in two directions.
After that, it is supplied to the front work machine elevating valves V2 and V1.

Hydraulic cylinder in which pressure oil controlled by the front work machine elevating valves V2 and V1 lifts the front lift arm 37
Supplied to 59.

In addition, the pressure oil controlled by the front work machine elevating valves V2 and V1 is also supplied to a hydraulic cylinder that moves up the side mowers ML and MR.

From the pressurized oil outlet 55, 56, 57, these front mower devices
It is supplied to the hydraulic cylinder that raises the MF and the side mower devices ML and MR.

Thus, the front mower device MF and the side mower ML / MR
To the front work machine elevating valves V2 and V1 in order to raise the pressure, and supply the priority branch pressure oil of the flow valve CV to the surplus oil squirted at the flow valve CV from the port g via the oil passage j. Is supplied to the rear working machine elevating valve V3. Pressure oil is supplied to a hydraulic cylinder 58 that rotates the rear lift arm 24 by pressure oil controlled by the rear working machine lifting valve V3.

Then, the pressure oil and the return oil which are not used in the front working machine elevating valves V2 and V1 are joined by the oil passage d to the junction b of the oil passage j.
And is supplied to the rear work machine elevating valve V3.

That is, the priority is given to the pressure oil supplied to the front working machine elevating valves V2 and V1.

However, the port h is the preferred pressure oil, but a small amount of the pressure oil. About 1/3 of the pressure oil discharged from the hydraulic pump P is supplied from the port h to the front working machine elevating valves V2 and V1. , 2/3
From the port g to the direction in which it is supplied to the rear working machine elevating valve V3. If it merges at the junction b, the discharge amount of the hydraulic pump P becomes the same as the discharge amount of the hydraulic pump P.
It is supplied to.

Next, with reference to FIGS. 5, 6 and 7, the front working machine elevating mechanism of the present invention will be described.

Front lift arm 37 protruding from the tractor side,
A lift link 93 is pivotally supported, and a lower end of the lift link 93 is pivotally supported at an intermediate portion of the lower link 36.

At the tip of a special top link 85 pivotally supported at the front end of the tractor, a bracket 91 at the upper end of the "reverse U" frame 80 is pivotally supported.

A vertical link 84 is pivotally supported in the middle of the special top link 85, and a central engaging arm 94 is pivotally connected to a lower end of the vertical link 84. Below the upper and lower links 84, an engaging body 95 with which the rear end of the central engaging arm 94 is engaged on the upper surface.
Is fixed.

A rear end of the suspension arm 82 is pivotally supported at an intermediate portion of the vertical link 84.

The suspension arm 82 is projected forward, and an intermediate portion thereof is pivotally supported by a swing link 92 suspended from a bracket 91 of the "reverse U" frame 80, and a suspension chain 89 is provided at the front end. Are connected. The lower end of the suspension chain 89 is pivotally connected to the rear of the front mower device MF.

The front end of the lower link 36 described above is a "reverse U" shaped frame
The floating rods 81 are pivotally supported by lower link pivot pins 83 arranged at the lower left and right ends of the 80, and on an installation shaft 98 which is installed between the left and right ends of the "reverse U" -shaped frame 80. ing.

However, when the front mower device MF is lifted by the front lift arm 37, the floating rods 81, from a certain angle position, the outer engaging arms are so formed as to be integrated with the "reverse U" -shaped frame 80. 96 ・ 96 and outer engagement piece
86 ・ 86 are provided.

With respect to the mounting shaft 98, an "inverted U" -shaped frame 80,
The floating rods 81 are loosely fitted and are pivotally supported, but the center engaging arm 94 and the outer engaging arms 96 are fixed via engaging keys.

The power is transmitted from the front PTO shaft 31 to the input shaft 90 of the gearbox 87 via the joint shaft 97. The tips of the floating rods 81 are pivot shafts 88 of the front mower device MF.
Is pivoted to.

(F) Operation of the invention In the state of FIG. 6, the front mower device MF is grounded on the ground surface and is in a floating state, and the front mower device MF is pivotally supported by the tips of the floating rods 81. The rear part of the floating rod 81
Since the floating rods 81 are not in contact with the 86, the floating rods 81 can freely rotate up and down around the erection shaft. Further, since the rear portion of the front mower device MF is suspended by the suspension chain 89, it can rotate upward.

From this state, when the lower link 36 is started to rotate upward by the front lift arm 37 via the lift link 93,
Until the rear ends of the floating rods 81 contact the outer engagement pieces 86, the front ends of the front mower device MF do not rise only by the rotation of the floating rods 81.

The rear end of the front mower device MF is a "reverse U" shaped frame
Since the suspension chain 89 is lifted by 80, the lifting starts.

Then, from the time when the outer engagement pieces 86 contact the rear ends of the floating rods 81, the front ends of the floating rods 81 start to rotate upward to raise the front end of the front mower device MF. It is.

By the upward rotation of the lower link 36, the central engagement arm 94
The part where the rear end has contacted the engaging body 95 is opened,
As the part 98 rises, the outer engagement arm 96
Pivots in a direction to lower the rear end, the outer engagement pieces 86 push the rear ends of the floating rods 81 downward, and the front ends rise rapidly.

Similarly, since the suspension arm 82 also sharply pivots upward at the tip, the suspension chain 89 causes the front mower device MF to rotate.
It lifts the rear end. That is, when ascending, the lower link 36 and the floating rods 81
The floating rods 81, 81 come into contact with each other and rise as a single piece. However, since the outer engagement pieces 86, 86 rotate downward, the lower part of the erection shaft 98 is raised as it rises. The bending angle between the link 36 and the floating rods 81 gradually increases, and the front mower device MF rises more than the rotation of the lower link 36.

Similarly, the suspension arm 82 that suspends the rear end of the front mower device MF also performs the upward rotation by the rotation angle of the lower link 36 or more.

(G) Effects of the Invention The present invention is configured as described above, and has the following effects.

The front mower device is configured as in claim (1).
In the mowing state where the MF is lowered and touched down, the front mower device
Since the MF can move up and down freely, it can follow the rough surface of the ground.

Also, since the floating mechanism is mechanically constituted by a link, a shaft and an arm, such as an erected shaft 98 interposed between the special top link 85 and the lower link 36, an upper and lower link 84, and outer engagement arms 96 and 96. It can perform reliable operation,
It allows free movement of pressure oil on the side of the tractor's hydraulic device, compared to the case where a hydraulic floating mechanism is provided.
The free up and down movement was surely performed.

Since the construction is as described in claim (2), the working machine rapid ascent mechanism can be constituted by using the link mechanism, which constitutes the floating mechanism, as it is, so that the floating mechanism and the rapid ascent mechanism are separately constructed. This makes it possible to provide a low-cost and effective working machine elevating mechanism.

Also, a front mower device MF attached to the front of the tractor
When it is lifted, it can be attracted toward the tractor by abruptly turning upward, so that the total length of the state in which the working machine is mounted can be shortened.

Since the priority circuit based on the flow valve CV is branched to the front working machine elevating valve V2 / V1 side, regardless of whether the working machine at the rear is up or down,
Since the work implement at the front can be lifted, it is possible to reliably avoid obstacles appearing in front of the work implement.

Also, the pressure oil supplied to the front work machine lift valves V2 and V1 is
Because of the small amount of 1/3, the up and down speeds were slowed down, and the sudden descent caused the driver to bite the lawn, impacting the running condition of the tractor and preventing the operator from swinging forward.

[Brief description of the drawings]

1 is an overall side view of the agricultural tractor of the present invention, FIG. 2 is a plan view of the same with the safety frames 26 and 27 and the canopy 29 removed, FIG. 3 is a plan view of a state with the body cover C removed, 4th
FIG. 5 is a plan view showing a state in which mower devices are arranged in front or rear of the tractor and sideways. FIG. 5 is a perspective view of the front working machine mounting device of the present invention, FIG. 6 is a side view thereof, and FIG. FIG. 8 is a front sectional view of a part of the same, and FIG. 8 is a hydraulic circuit diagram of the working machine elevating mechanism. P… Hydraulic pump MF… Front mower device 36… Lower link 37… Front lift arm 81… Floating rod 82… Hanging arm 84… Vertical link 85… Special top link 89… Hanging chain 94 ... Center engaging arm 86 ... Outer engaging piece 96 ... Outer engaging arm 98 ... Equipment shaft

Claims (3)

(57) [Claims] 1. An inverted U-shaped frame 80 is pivotally supported at the tip of a top link 85 of a tractor, the upper end of an upper and lower link 84 is pivotally supported in the middle of the top link 85, and the lower end of the upper and lower link 84 is pivotally supported. The center engaging arm 94 is fixed to a mounting shaft 98 provided between the left and right sides of the "reverse U" -shaped frame 80, and outer engaging arms 96, 96 which rotate integrally with the central engaging arm 94 are provided. At the left and right ends of the shaft 98, the floating rods 81
The outer ends of the floating rods 81, 81, which support the ends of the lower link 36 at the lower left and right ends of the 81, 81, and the middle of the floating rods 81, are provided on the outer engaging arms 96, 96. It is possible to contact the engagement pieces 86, 86 from below, and the floating rod 81
-The tip of the mower device MF is pivotally supported at the tip of 81, and the tractor side of the mower device MF is suspended via a chain 89 between the "reverse U" -shaped frame 80 and the upper and lower links 84 so as to be rotatable. It is configured to be suspended at the tip of the arm 82, and when the mower device MF is grounded, the floating rod 81
A lifting machine for agricultural tractors, wherein the mower device MF can be moved up and down by releasing the contact state of the 86. 2. An inverted U-shaped frame 80 is pivotally supported at the tip of a top link 85 of the tractor, the upper ends of the upper and lower links 84 are pivotally supported in the middle of the top link 85, and the lower ends of the upper and lower links 84 are pivotally supported. The center engaging arm 94 is fixed to a mounting shaft 98 provided between the left and right sides of the "reverse U" -shaped frame 80, and outer engaging arms 96, 96 which rotate integrally with the central engaging arm 94 are provided. At the left and right ends of the shaft 98, the floating rods 81
The outer ends of the floating rods 81, 81, which support the ends of the lower link 36 at the lower left and right ends of the 81, 81, and the middle of the floating rods 81, are provided on the outer engaging arms 96, 96. It is possible to contact the engagement pieces 86, 86 from below, and the floating rod 81
-The tip of the mower device MF is pivotally supported at the tip of 81, and the tractor side of the mower device MF is suspended via a chain 89 between the "reverse U" -shaped frame 80 and the upper and lower links 84 so as to be rotatable. The outer engaging pieces 86, 86 and the floating rods 81, 81 are engaged with each other when the working machine is raised, and the outer engaging pieces 86, 86 are pivoted downward. Thus, the lifting angle of the mower device MF is made larger than the lifting angle of the lower link 36. 3. The working machine lifting mechanism for an agricultural tractor according to claim 2, wherein the pressure oil supplied to the front working machine lifting valve for controlling the front mower device MF to be lifted is supplied to the rear hydraulic lifting device. A lift mechanism for agricultural tractor work equipment, characterized in that it is smaller than oil and has a flow valve CV interposed to branch off preferentially.