JP3537323B2 - Tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tractor for connecting a ground working device such as a tilling rotary so as to be able to drive up and down. Attach a lift arm and use a hydraulic cylinder that swings and drives this lift arm.
The present invention relates to a piston rod which is disposed outside a rear portion of a transmission case in a state where a tip of a piston rod is connected to a lift arm and a lower end of a cylinder tube is connected to a transmission case.

[0002]

2. Description of the Related Art In a tractor of this type, a hydraulic cylinder for swinging and driving a lift arm is disposed outside a rear portion of a transmission case. Thus, there is an advantage that the seat arranged at the upper part of the transmission case can be lowered.

In a conventional tractor having such advantages, a piston rod of a hydraulic cylinder is exposed to the outside.

[0004]

Therefore, according to the above-mentioned conventional technique, mud or flying objects adhere to or hit the piston rod, and furthermore, a seal (dust seal or the like) between the piston rod and the cylinder tube. However, since the mud and flying objects tended to accumulate there, the piston rod and the seal were easily damaged and corroded.

An object of the present invention is to prevent damage and corrosion of a piston rod and a seal due to mud and flying objects.

[0006]

The features, operations and effects of the first aspect of the present invention are as follows.

[Features] A lift arm that can swing up and down around a left-right axis is attached to a transmission case arranged at the rear of the fuselage. A hydraulic cylinder that swings and drives this lift arm is attached to the lift arm with the tip of the piston rod as the lift arm. A tractor connected to the rear of the transmission case with the lower end of the cylinder tube connected to the transmission case, the cylinder cover covering the outer periphery of a piston rod in a state where the hydraulic cylinder is extended. The piston cover is attached to the piston rod while moving integrally with the piston rod, and the cylinder cover
A structure that opens forward, covering the left, right, and back of the rod
In that it is .

According to the first aspect of the present invention, the cylinder cover covering the outer periphery of the piston rod is attached to the piston rod so as to move integrally with the piston rod with respect to the cylinder tube, so that the entire cylinder can be expanded and contracted. Since the piston rod and the seal are covered with the cylinder cover, it is possible to prevent mud and flying matter from adhering to the piston rod and from collecting mud and flying matter in the seal portion. Also,
Hydraulic cylinder is located behind the rear of the transmission case
The transmission case can cover the hydraulic cylinder
Noting that the cylinder cover
Open forward to cover the left, right and back of the ston rod
Because of the structure of
While preventing damage and corrosion to the rod and seal,
Attach the stone cover to the piston rod from the side
Yes, without removing the piston rod from the lift arm
A piston cover can be attached. In other words, oil
Attach piston cover with pressure cylinder assembled
Can be opened. Moreover, because the front is open,
Easy muddy water flowing into the piston cover during car washing
Can be discharged.

[Effects] Therefore, according to the first aspect of the present invention, the piston rod and the seal can be prevented from being damaged or corroded by mud or flying objects by simply improving the structure by simply providing the cylinder cover. In addition, assembly workability can be improved, and at the time of car washing
Muddy water that has flowed into the piston cover
Can be discharged reliably without collecting in the bar
You.

According to the second aspect of the present invention, the features, actions,
The effects are as follows.

[Features] A transmission case located at the rear of the fuselage.
Attach a lift arm that can swing up and down
The hydraulic cylinder that drives the arm to swing
Of the cylinder tube to the lift arm and
With the lower end connected to the mission case,
A tractor located outside the rear of the case,
With the hydraulic cylinder extended, move the outer circumference of the piston rod
Fix the cylinder cover to cover the cylinder tube.
Take the piston rod while moving it with the piston rod.
The hydraulic cylinder is attached to the cylinder
The chamber located on one side of the piston in the tube is called the oil chamber.
Single-acting hydraulic pressure with the chamber located on the other side as the air chamber
Composed of a cylinder and communicates with the air hole formed in the air chamber
Through the tube into the mission case
The cylinder cover moves together with the piston rod
How to move up and down between the cylinder cover and the communication tube
A tube escape part that allows relative movement in
The point is.

[Operation] According to the second aspect of the invention, similarly to the first aspect, the piston
Insert the cylinder cover that covers the outer circumference of the rod into the cylinder tube
Fixed with the piston rod
To the hydraulic rod to extend and retract the hydraulic cylinder.
Cover the piston rod and seal with the cylinder cover
The piston rod for mud and flying objects.
Prevent accumulation of mud and flying objects on clothes and seals
Can be.

According to the second aspect of the present invention, the hydraulic
Air chamber inside the transmission case via a tube
To allow oil leaking from the oil chamber to the air chamber to drain outside.
Return to the mission case without letting it go out
The gap between the piston rod and the cylinder tube
Only small items such as dust seals are required.

[Effect] Therefore, according to the second aspect of the present invention, the cylinder cover is provided.
The piston rod and the seal
In addition to the effect of preventing damage and corrosion caused by mud and flying objects
In addition, the sealing performance can be improved with a simple seal.
Was.

According to the third aspect of the present invention, the features, actions,
The effects are as follows.

[0016] [Characteristics] In a feature of the present second invention, fitted with a control valve of another hydraulic equipment on the upper surface of the transmission case is a hydraulic cylinder, communicates Spoken via drain port into the transmission case of the control valve Is connected to the inside of the transmission case.

[Operation ] According to the third aspect of the present invention, since the tube is communicated with the transmission case through the drain port of the control valve, a dedicated connection port for communicating the tube with the transmission case is unnecessary. It is.

[0018] [Effect] Thus, according to the third invention, while employing the format to return the leaked oil in the hydraulic cylinders in the transmission case, can be the transmission case what structure simple.

According to the fourth aspect of the present invention, the features, functions,
The effects are as follows.

[Features] A lift arm which can swing up and down around a left-right axis is attached to a transmission case arranged at the rear part of the fuselage, and a hydraulic cylinder which swings the lift arm is used. A tractor connected to the rear of the transmission case with the lower end of the cylinder tube connected to the transmission case, the cylinder cover covering the outer periphery of a piston rod in a state where the hydraulic cylinder is extended. together it is attached to the piston rod in a state of moving the piston rod integral with respect to, silica with respect to the piston rod
The mounting structure of the cylinder cover is the upper end of the piston rod.
The upper end piece that locks against the
And the upper end of the cylinder cover around the horizontal axis.
And a shaft support portion that is swingably connected with the
Upper end of the cylinder cover with respect to the upper end of the ton rod
In a suspended position with the piece locked against the cylinder tube
Position relative to the center of the horizontal axis.
The cylinder cover is mounted so that changes are possible
Have .

[0021]

[0022]

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG.
An engine E and a boarding operation unit 3 are mounted side by side on a body provided with a pair of left and right steering front wheels 1 and a pair of left and right driven rear wheels 2, and a ground working device 4 such as a tilling rotary is mounted on a rear part of the body. It is equipped with a three-point link mechanism 5 that is connected in a freely ascending and descending and rolling manner, and is provided with an elevating drive means for elevating and lowering the ground work apparatus 4 and a rolling drive means for rolling the ground work apparatus 4.

The front wheel 1 is supported by the body via a front axle case. The drive rear wheel 2 has a rear axle case 8 mounted on a transmission case 7 constituting a part of the body rear as shown in FIG. Supported through. As shown in FIGS. 2 and 8, the transmission case 7 includes a case body 7A having an upper opening and a cover plate 39 for closing the upper opening, and includes a power take-out shaft 60 protruding rearward.

The three-point link mechanism 5 includes a ground working device 4
A pair of left and right lower links 9 that swingably move up and down
And a top link 10 that regulates the front-back posture of the ground working device 4 accompanying the swinging up and down movement. As shown in FIG. 2, the lower link 9 is connected to the rear axle case 8 so as to be vertically swingable about a first left-right axis P1, and the top link 10 is connected to the transmission as shown in FIG. First bracket 11 connected to the rear of case 7
Are connected so as to be able to swing up and down around the second left-right axis P2.

As shown in detail in FIGS. 2 and 4, the lifting drive means pivots a support shaft 28 around a third left-right axis P3 on a lift bracket 27 connected to the upper surface of the transmission case 7. And a pair of left and right lift arms 12 are attached to both ends of the support shaft 28 via splines so as to rotate integrally with the support shaft 28, that is, swing vertically. A pair of left and right hydraulic cylinders are provided for connecting the lift link 12 and the lower link 9 so that the lower link 9 swings up and down. 14 is provided.

As shown in detail in FIG. 5, the hydraulic cylinder 14 has a piston 16 inside a cylinder tube 15.
Is a single-acting hydraulic cylinder in which a chamber located on one side is an oil chamber 17 and a chamber located on the other side is an air chamber 18, and the tip of a piston rod 19 is connected to a lift arm 12 via a shaft 20. Pivotally connected to the cylinder tube 15
2nd bracket 2 which connects the lower end of
1 is arranged at the rear outside of the transmission case 7 in a state of being pivotally connected to the transmission case 1 via a shaft 22. Then, the lift arm 12 is raised and rocked against the load by extending the operation with the supply of the pressure oil, and the lift arm 12 is lowered and rocked by the load by performing the shortening operation with the drainage of the oil. . At the lower end of the cylinder tube 15, a grease nipple 15A for injecting grease for lubricating between the shaft hole 15a formed at the lower end and the shaft 22 is attached. It is moved by being pressed and pressed by 16. In other words, the piston rod 19 is free to move in the extending direction independently of the piston 16 by one side.

As shown in FIG. 2 and in detail in FIGS. 5 and 6, the hydraulic cylinder 1
A cylinder cover 23 that covers the outer periphery of the piston rod 19 with the 4 extended is attached to the cylinder tube 15 so as to move integrally with the piston rod 19. As shown in FIG. 7, the cylinder cover 23 has a U-shaped cross section that is open forward to cover the left, right, and rear of the piston rod 19, and the upper end piece 23 a is an upper bracket of the piston rod 19. 19a
The upper end rising piece 23b is fixed to the upper end bracket 19a via a bolt 24 in a state where the upper end rising piece 23b is locked to the piston rod 19. In other words, the fixie
Mounting structure of cylinder cover 23 to connecting rod 19
The structure corresponds to the upper end bracket 19a of the piston rod 19.
The upper end piece 23a to be locked by pressing the upper end of the cylinder cover 23
A locking portion provided for the cylinder cover 23
The upper rising piece 23b is connected to the upper bracket 19a.
And a shaft support portion formed by bolts 24.

A dust seal 25 is interposed between the cylinder tube 15 and the piston rod 19.

The above-mentioned rolling drive means is shown in FIGS.
As shown in FIG. 1, one of the lift rods 13 is formed of a double-acting hydraulic cylinder 26 which can be extended and contracted and fixed, and the hydraulic cylinder 26 is extended and contracted so that one lower link 9 becomes the other lower link 9. The ground work device 4 is rolled by being swung with respect to. That is, the hydraulic cylinder 26 is an example of another hydraulic device.

As shown in the hydraulic circuit of FIG. 3, the means for controlling the two hydraulic cylinders 14 and 26 includes a control valve 29 for controlling rolling of the hydraulic cylinder 26 and a control valve 29 for raising and lowering the hydraulic cylinder 14 for raising and lowering. A control valve 30 for control is provided.

The control valve 29 for rolling control
Is provided with a flow priority valve 31 for diverting the pressure oil from the hydraulic pump P driven by the engine E into a control flow and an excess flow,
And the hydraulic cylinder 26 is extended to operate the hydraulic cylinder 26, the control flow is supplied to the hydraulic cylinder 26 to shorten the hydraulic cylinder 26, and the control flow is stopped. An electromagnetically operated rolling valve 32 operable to switch between a neutral state in which the cylinder 26 is fixed is provided.

The control valve 30 for raising / lowering control is divided into a lifting / lowering control valve portion 30A and a falling speed (falling speed) adjusting valve portion 30B. The lift control valve section 3
0A is an ascending valve 33 for supplying the excess flow from the flow priority valve 31 to the hydraulic cylinder 14, an electromagnetically operated ascending pilot valve 34 for operating the ascending valve 33 by pilot pressure, and a hydraulic cylinder 14. The transmission case 7 includes a descending valve 35 for discharging hydraulic oil, and an electromagnetically operated descending pilot valve 36 for operating the descending valve 35 with pilot pressure. Each of the ascending pilot valve 34 and the descending pilot valve 36 changes a pilot pressure by changing an opening degree in direct proportion to a current value supplied to an electromagnetic solenoid,
The openings of the ascending valve 33 and the descending valve 35 are adjusted according to the change in the pilot pressure. The drop speed adjusting valve unit 30B provides a check valve 37 for supplying only the hydraulic oil from the ascending valve 33 to the hydraulic cylinder 14, and a resistance corresponding to the operation amount of the operating tool 38A to the drainage from the hydraulic cylinder 14. A variable throttle valve 38 that can be fully closed to adjust the falling speed is provided.

Control valve 29 for rolling control
The lifting control valve unit 30A and the falling speed adjusting valve unit 30B are, as shown in detail in FIGS.
The transmission case 7 is attached to the upper surface of a lid plate 39 closing the upper opening 7a formed in the transmission case 7 in a state of being arranged from the rear to the front in the order described. Inside the cover plate 39, an oil passage 40 from the control valve 29 for rolling control to the elevation control valve section 30A, and an elevation control valve section 30A
And an oil passage 41 from the oil passage to the falling speed adjusting valve portion 30B.

The control valve 29 for rolling control has a pair of connecting portions 43 for rolling for connecting a pair of hydraulic hoses 42 to the hydraulic cylinder 26 for rolling, and a pair of connecting portions 43 for connecting the inside of the transmission case 7. A pair of drain connection portions 45 communicating with each of the drain ports 44 and a pump connection portion 47 for connecting to a hydraulic pipe 46 from the hydraulic pump P are provided so as to protrude to the outside. The valve section 30B has a pair of hydraulic hoses 48 for the hydraulic cylinder 14 for lifting and lowering.
Are provided in a state of protruding outside.

Each of the drain connection portions 45 is shown in FIG.
As shown in the figure, the air cylinder 18 of the lifting hydraulic cylinder 14 communicates with a corresponding one of the ventilation holes 50 through a ventilation tube 51. That is, the air chamber 18
Communicates with the inside of the transmission case 7 through the ventilation hole 50, the tube 51, the drain connection part 45, and the drain port 44. The cylinder cover 23 has the above-described structure.
Piston while avoiding the existing position of ventilation tube 51
Cylinder cover 23 moves vertically with rod 19
The tube relief to allow relative movement with
In this example, as shown in FIGS.
In addition, the cylinder cover 23 itself is formed in a U-shaped cross section.
And, the opening portion serves as the tube escape portion.
It is configured to play a role.

As shown in FIGS. 4 and 8, the control valve 29 for rolling control and the elevation control valve section 30A
The means for attaching the drop speed adjusting valve portion 30B to the upper surface of the lid plate 39 is a means for attaching the bolt 52 from above by tightening the bolt 52. The lid plate 39 is a bolt that is tightened to the case body 7A from above. It is fixed by 53. The lift bracket 27 is jointly fastened to the cover plate 39 and the case body 7A by bolts 53 while being placed on the cover plate 39.

The riding driver 3 has a seat 3A and a steering handle 3B disposed between the left and right rear wheel fenders 54. The seat 3A is, as shown in FIGS. A floor seat 5 for mounting a seat, which is arranged above the transmission case 7 integrally with the transmission case 54.
5 is attached.

As shown in FIG. 4, a maintenance opening 57 which is opened and closed by a detachable lid 56 is formed in the floor seat 55 at a position corresponding to the installation portion of the control valves 29 and 30 groups. The opening 57 is formed such that the installation section outer shell is located inside the outer shell in plan view. The seat 3A is attached to the lid 56 of the floor seat 55.

Another Embodiment In the above embodiment, a rolling hydraulic cylinder was shown as another hydraulic device 26. However, as another hydraulic device 26, the lower link 9
May be a hydraulic cylinder that swings right and left, that is, shifts the ground working device 4 left and right.

In the above embodiment, the cylinder cover 23 is configured to cover the entire outer periphery of the piston rod 19.

[Brief description of the drawings]

FIG. 1 is a side view

FIG. 2 is a cutaway side view of the rear of the tractor.

FIG. 3 is a hydraulic circuit diagram

FIG. 4 is a plan view of the rear part of the tractor.

FIG. 5 is a cutaway side view showing the expansion and contraction operation of the hydraulic cylinder.

FIG. 6 is a cross-sectional plan view of the cylinder cover.

FIG. 7 is a perspective view of a cylinder cover.

FIG. 8 is a cutaway side view of a valve installation portion.

FIG. 9 is a front view of a seat mounting portion.

[Explanation of symbols]

7 Mission case 12 Lift arm 14 Hydraulic cylinder 15 Cylinder tube 16 piston 17 Oil chamber 18 air chamber 19 Piston rod 23 Cylinder cover 26 Different hydraulic equipment 29 Control valve 44 Drain port 50 vents 51 tubes P3 Left and right axis

Continuation of front page (72) Inventor Akio Hattori 4-15-5 Mokudori, Mihara-cho, Minamikawachi-gun, Osaka Prefecture Inside of Kubota Seiki Co., Ltd. -80806 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A01B 63/00 A01B 63/10 B62D 49/02 B62D 49/00

Claims (4)

(57) [Claims] A lift case capable of swinging up and down around a left-right axis is attached to a transmission case arranged at the rear of the machine body, and a hydraulic cylinder for swinging the lift arm is provided.
A tractor arranged outside a rear part of a transmission case in a state where a tip of a piston rod is connected to a lift arm and a lower end of a cylinder tube is connected to a transmission case, wherein the hydraulic cylinder is extended and together is attached to the piston rod in a state of moving the cylinder cover covering the outer periphery of the piston rod integral with respect to the cylinder tube, the cylinder cover, the left and right and rear of the piston rod
The tractor has a structure that is opened forward in a state of covering the tractor. 2. A transmission case located on the rear of the fuselage.
Equipped with a lift arm that can swing up and down around the right axis
The hydraulic cylinder that drives the lift arm to swing
Connect the tip of the piston rod to the lift arm and
The lower end of the cylinder tube is connected to the transmission case
Tractor located outside the rear of the transmission case
A is, outside of the piston rod in a state that the hydraulic cylinder is extended
Pierce the cylinder cover covering the circumference to the cylinder tube.
To the piston rod while moving integrally with the ston rod
The hydraulic cylinder is attached and the piston
The chamber located on one side of the
A single-acting hydraulic cylinder with the air chamber as the air chamber.
The air holes formed in the air chamber are mixed through tubes for communication.
To the cylinder cover and move integrally with the piston rod to the cylinder cover.
Up and down movement of the cylinder cover and the communication tube
Form a tube relief to allow relative movement in the direction
There is a tractor. 3. A control valve of a hydraulic device different from the hydraulic cylinder is mounted on an upper surface of a transmission case, and a communication tube is connected to the transmission case through a drain port of the control valve into the transmission case. is there
The tractor according to claim 2 . 4. A lift arm that can swing up and down around a left-right axis is attached to a transmission case arranged at the rear of the fuselage, and a hydraulic cylinder that swings and drives the lift arm is provided.
A tractor arranged outside a rear part of a transmission case in a state where a tip of a piston rod is connected to a lift arm and a lower end of a cylinder tube is connected to a transmission case, wherein the hydraulic cylinder is extended and A cylinder cover covering the outer periphery is attached to the piston rod in a state of moving integrally with the piston rod with respect to the cylinder tube, and the cylinder cover is attached to the piston rod.
The structure consists of an upper end that locks against the upper end of the piston rod.
A locking part provided with a piece at the upper end of the cylinder cover;
Connect the upper end of the Linda cover so that it can swing around the horizontal axis
A shaft support portion, and the cylinder cover has an upper end with respect to the piston rod.
Hold the upper end piece in the hanging position with the cylinder tube
Relative to the vertical axis, and around the horizontal axis.
A cylinder cover is attached so that the posture can be changed
It is to have a tractor.