JP3537257B2 - Tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a tractor,
More specifically, the present invention relates to an improvement of a hydraulic cylinder for operating a working device connected to a traveling vehicle body up and down.

[0002]

2. Description of the Related Art Conventionally, there is a tractor constructed as described above in Japanese Utility Model Laid-Open Publication No. 54-115306. In this conventional example, a cylinder and a tractor are mounted on the upper surface of a case at the rear of a vehicle body. A lifting device driven up and down by a cylinder is provided, and a working device connected to the rear of the vehicle body via a member (link mechanism) so as to be able to move up and down can be moved up and down by swinging the lift arm.

[0003]

However, the working device is connected to the rear end of the vehicle body via a connecting member such as a link mechanism so as to be able to move up and down freely, and the connecting member is operated by the swinging power of the lift arm. In the case of raising and lowering the working device, the system for raising and lowering the working device becomes large, and there is room for improvement. In particular, there is room for improvement in a small tractor that needs to be constructed at a low cost, because the number of parts tends to increase and the cost reduction is impaired.

An object of the present invention is to rationally configure a tractor capable of raising and lowering a working device with a simple structure by reducing the number of components of a drive lifting system.

[0005]

A first feature of the present invention (claim 1) is to provide a hydraulic cylinder in which the direction of expansion and contraction is set to the front-rear direction with respect to the rear position of the traveling vehicle body, and the hydraulic cylinder is connected to the front part. on the side, together with the provided setting its piston rod on the rear side, the hydraulic cylinder rear end portion side to form an oil port for supply and discharge of hydraulic fluid into the cylinder space of the rear side of the piston of the An air port is formed at the front end of the hydraulic cylinder to supply and discharge air in the cylinder space on the front side of the piston when the piston operates.
Of the fuel tank and the bottom of the fuel tank located above it
The hydraulic pressure
The front end of the cylinder is located at the back
Is located near the rear opening of the placement space and the fuel tank
Insert the hydraulic cylinder so that it is covered by
And a front end of the cylinder portion is supported on the back side of the arrangement space so as to be swingable around a horizontal axis, and a connecting portion for a working device connected to the traveling vehicle body so as to be able to move up and down is connected to the piston rod. The air port is formed at the rear end position, and the air port is located at the far side of the arrangement space , and the operation is as follows.

A second aspect of the present invention (claim 2), running
Set the telescopic direction to the front and rear direction with respect to the rear
The hydraulic cylinder with its cylinder on the front
Set the ston rod on the rear side and prepare
The front end of the Linda section swings freely around the horizontal axis to the vehicle body side
Work that is connected and connected to the traveling vehicle body so as to be able to move up and down
Connect the connection to the device at the rear end of the piston rod
A system is formed that uses stored oil in a transmission case provided in a traveling vehicle body as hydraulic oil supplied to the hydraulic cylinder via a hydraulic pump, and the hydraulic cylinder is provided on a rear side of a piston. A blaster configured to retract the piston rod by supplying hydraulic oil to the cylinder space to raise the working device, and to supply and discharge air to the cylinder space in front of the piston when the piston is operated. a conduit, located between the cylinder space of said front side to the transmission case in point Ru tare formed in a state of communicating, their action is as follows.

A third feature of the present invention (claim 3) is that an oil passage for supplying and discharging hydraulic oil to and from a space inside the cylinder behind the piston of the hydraulic cylinder is disposed outside the hydraulic cylinder. The operation is as follows.

According to the first feature, the working device is connected to the traveling vehicle body, and the piston rod of the hydraulic cylinder is extended and contracted in a state where the working device is connected to the connecting portion at the end of the piston rod. By actuating, the working device can be raised and lowered, and the hydraulic cylinder can swing around the horizontal axis at the front end of the cylinder section. Even when the point is displaced in the vertical direction, this displacement is allowed by the swing displacement of the hydraulic cylinder.

That is, in this configuration, the working device can be moved up and down by connecting the piston rod and the working device, so that not only the lift arm is not required as in the conventional example but also the direct connection to the traveling vehicle body. Since the work apparatus can be moved up and down, a connecting member for supporting the work apparatus to be able to move up and down with respect to the traveling vehicle body as in the conventional example is not required.

According to the second feature, since the working device is raised by the operation of the piston rod toward the contraction side, the present invention is compared with a conventional device in which the working device is raised by a pushing operation. In the configuration described above, it is difficult to buckle, so the cross-sectional area of the piston rod can be reduced.Moreover, when the piston operates, air is supplied and discharged between the cylinder space on the front side of the piston and the inside of the transmission case, For example, when the piston rod is contracted by the supply of the hydraulic oil, an amount of air substantially equal to the amount of the hydraulic oil used for the supply is sent into the transmission case through the breather pipe (in the reverse direction). The air pressure in the mission case hardly changes, and the inconvenience of sucking outside air does not occur.

According to the third feature, since the supply and discharge of the hydraulic oil are performed via the tubular member outside the hydraulic cylinder, for example, the hydraulic oil is supplied and discharged in comparison with the case where the oil passage is formed integrally with the hydraulic cylinder by casting. It is easy to make oil passages that are complicated routes,
In addition, since it is possible to use an off-the-shelf hydraulic cylinder, the cost can be reduced.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, an engine 4 is arranged at a front portion of a traveling vehicle body 3 having a front wheel 1 and a rear wheel 2 that can be steered, and a transmission case 5 is arranged at a rear portion of the vehicle body. A differential case 6 for the front wheels 1 is arranged at the front of the vehicle body, and a drive shaft 7 for transmitting the power from the engine 4 to the transmission case 5 and a power for transmitting the power from the transmission case 5 to the differential case 6 for the front wheels 1. A transmission tractor 8 is provided, and a steering wheel 9 is provided at a central portion of the vehicle body 3 and a driver's seat 10 is provided at a rear portion of the vehicle body 3 to constitute an agricultural tractor.

The transmission case 5 incorporates a gear type transmission (not shown) for shifting the power from the engine 4 and a differential (not shown) for transmitting the transmission power to the rear wheels 2. A transmission system for transmitting the traveling speed change power to the differential case 6 of the front wheels 1 is provided. As shown in FIGS. 2 to 4, a U-shaped engaging member 12 is formed at the rear position of the transmission case 5 at the rear end of the pair of left and right plates 11 so as to connect the working device. An external power take-off shaft 13 for transmitting power to the working device is formed on the rear surface of the transmission case 5 at a position overlapping the hitch H in a side view.

At the upper position of the transmission case 5, there is provided a hydraulic cylinder C for raising and lowering the working device. In other words, the hydraulic cylinder C is set in the front-rear direction of the traveling vehicle body 3 in the telescopic direction, the double-acting hydraulic cylinder in which the cylinder portion 14 is set to the front and the piston rod 16 connected to the piston 15 is set to the rear. A cylinder C is used, and the front end of the cylinder portion 14 is connected to the upper surface of the transmission case via a bracket 17 so as to be swingable around a horizontal axis X. Are provided.

As shown in FIGS. 5 and 6, a support shaft 21 fixed to the bracket 17 is provided at a position coaxial with the horizontal axis X, and is fixed to a front end position of the cylinder portion 14. The support member 22 is moved around the shaft axis
It is fitted outside so as to be freely rotatable. An oil passage is formed between the support shaft 21 and the support member 22 to allow the flow of the differential oil even during each rotation around the axis X. An oil passage is formed in the tubular member 23 for supplying and discharging hydraulic oil to and from the outer surface of the support member 22 and the rear end of the cylinder portion 14.

In this tractor, an oil passage system is formed so as to supply the oil stored in the transmission case 5 to the hydraulic cylinder C via the hydraulic pump 25 and the control valve V. In order to supply / discharge air to / from the cylinder, a breather conduit 26 made of a flexible material for supplying / discharging air from the cylinder is formed between the front end position of the cylinder 14 and the transmission case 5.

As shown in FIG. 3, the upper part of the hydraulic cylinder C and the lower part of the driver's seat 10 are set at an intermediate position between the left and right rear fenders 27 so that the resin fuel tank 2 is formed.
The fuel tank 28 has a bottom surface 28A at a central position in the left-right direction set high to secure an arrangement space for the hydraulic cylinder C.
The bottom surface at the left and right positions is brought into contact with a plate-like member 29 stretched on the upper surface of the fuel tank 28, and the position of the fuel tank 28 is regulated by sandwiching the front part of the fuel tank 28 from the left and right with a fender support stay 30.

FIG. 1 shows a state in which a rotary tilling device R as an example of a working device is connected. In this connected state, a connecting pin 31 formed at a front portion of the rotary tilling device R is shown.
Is engaged with the engaging member 12 of the hitch H on the vehicle body side (see FIG. 4), and a connecting bracket 32 integrally formed on the upper part of the rotary tilling device R is pinned with respect to the connecting portion 18 of the piston rod 16. 33 (see FIG. 6). Furthermore, the input shaft 34 of the rotary tilling device R
Are connected to the external power take-off shaft 13 via a universal joint 35.

When the rotary tilling device R is raised, the hydraulic oil is supplied to the hydraulic cylinder C, whereby the hydraulic oil is fed into the cylinder on the rear side of the piston 15, so that the piston rod 16 moves in the contracting direction. When the rotary tilling apparatus R is activated to swing around the axis of the connecting pin 31 in the ascending direction as shown by the imaginary line in FIG. , And the upward displacement of the connecting portion 18 of the piston rod 16 is allowed by the swinging of the hydraulic cylinder C about the lateral axis X with respect to the bracket 17. Oscillation between the support shaft 21 and the support member 22 maintains the communication state of the oil passage. In particular, in this configuration, since the oil stored in the transmission case 5 is used as the hydraulic oil for the hydraulic cylinder C, for example, when the hydraulic cylinder C is operated in the direction in which the piston rod 16 contracts as described above, the storage oil in the transmission case 5 is stored. The increase in the volume of the empty space in the transmission case 5 due to the lowering of the oil level is substantially equal to the decrease in the space at a position in front of the piston 15. 26 through hydraulic cylinder C
Inflow of air from the transmission case 5 eliminates the necessity of sucking outside air into the transmission case 5 or exhausting air from the transmission case 5 at all.

[0020]

Accordingly, a tractor capable of raising and lowering a working device with a simple structure having a small number of parts is rationally constructed (claim 1). Further, although the double-acting hydraulic cylinder is used as a single-acting hydraulic cylinder, no external air is sucked into the hydraulic cylinder (claim 2), and the hydraulic cylinder can be constructed at low cost (claim 2). 3).

[Brief description of the drawings]

FIG. 1 is an overall side view of a tractor.

FIG. 2 is a longitudinal sectional side view of a hydraulic cylinder part.

FIG. 3 is a rear view showing an arrangement of a hydraulic cylinder.

FIG. 4 is a plan view showing a connection state of the rotary tillage device to the hitch.

FIG. 5 is a hydraulic circuit diagram for a hydraulic cylinder.

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

[Explanation of symbols]

3 Traveling Car Body 5 Transmission Case 14 Cylinder 15 Piston 16 Piston Rod 18 Connecting Portion 24 Tubular Material 25 Hydraulic Pump 26 Breather Pipe 28 Fuel Tank 28A Bottom C Hydraulic Cylinder R Work Equipment X Lateral Axis

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-60111 (JP, A) JP-A-8-11557 (JP, A) Japanese Utility Model 60-122076 (JP, U) Japanese Utility Model Utility Model 60-122 7303 (JP, U) JP 513824 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A01B 63/10

Claims (3)

(57) [Claims] 1. A hydraulic cylinder having an extension / retraction direction set to the front-rear direction with respect to a rear position of a traveling vehicle body, the cylinder portion being provided on a front side, and the piston rod being provided on a rear side, and the hydraulic cylinder being provided with the hydraulic cylinder. An oil port is formed at the rear end of the cylinder to supply and discharge hydraulic oil to a space inside the cylinder at the rear side of the piston, and the front end of the hydraulic cylinder is located at the front side of the piston when the piston is operated. forming a Airport for performing air supply and discharge of the cylinder space, the mission
Of the upper case and the fuel tank
In the front-rear arrangement space formed between the bottom and the bottom, the oil
The front end of the pressure cylinder is located at the back, behind the hydraulic cylinder.
The end is located near the rear opening of the placement space and the fuel
Insert the hydraulic cylinder so that it is covered by the tank
The piston rod is mounted on a rear end of the placement space, the front end of the cylinder portion being supported swingably around a horizontal axis, and a connecting portion to a working device connected to the traveling vehicle body so as to be able to move up and down. The tractor is formed at a rear end position of the tractor, and the air port is located at a rear side of the arrangement space . 2. An extension / contraction direction with respect to a rear position of the traveling vehicle body.
The hydraulic cylinder with the
With the piston rod at the front and the piston rod at the rear.
The front end of this cylinder around the horizontal axis.
Swingably connected to the vehicle body side, and
The connecting part for the working device connected to the
A system is formed at a rear end position of a rod, and a system that uses stored oil in a transmission case provided in a traveling vehicle body as hydraulic oil supplied to the hydraulic cylinder via a hydraulic pump is formed. Supply of hydraulic oil to the cylinder space on the rear side of the piston to contract the piston rod to raise the working device. Further, when the piston is operated, air is supplied to the cylinder space on the front side of the piston. of Breza conduit for feeding exhaust, and formed in a state of communicating between the cylinder space of said front side to the transmission case tare belt Rakuta. 3. An oil passage for supplying and discharging hydraulic oil to and from a space inside the cylinder on the rear side of the piston of the hydraulic cylinder is formed of a tubular member disposed outside the hydraulic cylinder. Tractor.