JP3894823B2 - Tractor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a front axle member that supports a pair of left and right front wheels so as to be steerable is supported by a pair of left and right wheel support frames extending from the engine toward the front of the vehicle body, and the pair of front wheels are operated. The present invention relates to a tractor in which a power cylinder of an all-hydraulic power steering device that is operated in a direction is supported by the front axle member.
[0002]
[Prior art]
Conventionally, in the tractor, the valve mechanism of the all-hydraulic power steering apparatus is directly connected to the support shaft of the steering handle. In this case, there were the following problems.
[0003]
[Problems to be solved by the invention]
In other words, in the conventional tractor described above, the valve mechanism is positioned very close to the steering handle, and noise caused by driving sound such as hydraulic sound of the power steering device is likely to be generated in the driving unit. It was. In particular, in the case of a vehicle equipped with a driving cabin, noise is likely to occur due to the drive sound being transmitted to the cabin wall.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a tractor that is easy to avoid the generation of noise in a driving part, and that is easily connected to a power cylinder or equipped with a valve mechanism, despite having an all-hydraulic power steering device. .
[0005]
[Means for Solving the Problems]
Construction of the invention according to Claim 1, functions and effects are as follows.
[0006]
〔Constitution〕
An axle member before supporting a pair of right and left front wheels freely steered, rolling freely supported on a pair of left and right front wheel supporting frame extending in the vehicle body forward-looking from the engine and steering operating the pair of front wheels In the tractor supporting the power cylinder of the all hydraulic power steering device on the front axle member,
A valve mechanism for operating the power cylinder is positioned in front of the front axle member and between the pair of left and right front wheel support frames, so that the cylinder port of the valve mechanism faces obliquely forward with respect to the vehicle body. The valve mechanism is disposed so that the input shaft of the valve mechanism protrudes obliquely rearward with respect to the vehicle body from the end opposite to the side where the cylinder port is located, From the steering handle, an intermediate rotation shaft portion extends forward along the outer surface side of the front wheel support frame, and a universal joint is connected to the front end side of the intermediate rotation shaft portion, so that the universal joint and the valve mechanism The input shaft is linked and connected through the through hole of the front wheel support frame, and the cylinder port of the valve mechanism and the power cylinder are connected via a hydraulic hose. The pair of left and right front wheel support frame, over the front and rear in the position placing the valve mechanism is linearly formed in plan view.
[0007]
[Action]
The valve mechanism is disposed in front of the front axle member and between the pair of left and right front wheel support frames, and the input shaft of the valve mechanism and the steering handle are interlocked via an intermediate rotating shaft portion and a universal joint. Therefore, when the steering handle is rotated, the turning force is transmitted to the input shaft of the valve mechanism through the intermediate rotating shaft and the universal joint so that the valve mechanism can be operated by the steering handle. While the mechanism is guarded by the left and right front wheel support frames, it is easy to avoid the occurrence of noise in the driving unit by separating the valve mechanism far from the driving unit and transmitting hydraulic sound even if the power steering device is driven it can.
[0008]
When the valve mechanism and the power cylinder are connected by a hydraulic hose, the smaller the radius at the bent portion of the hydraulic hose, the stronger the elastic restoring force of the hose when performing the hose connection work, and the harder the work. In the present invention, because those are disposed a valve mechanism in a state where the cylinder port is opened in the direction of the obliquely forward direction to the vehicle body, when connecting a hydraulic hose, the bend radius becomes as much as possible on a large Connection work can be performed while minimizing the elastic restoring force generated.
Also, because the universal joint and the input shaft of the valve mechanism are linked and connected through the through hole of the front wheel support frame, the end of the valve mechanism on the side opposite to the side where the cylinder port is located However, the end on the side where the input shaft of the valve mechanism is located is one side while preventing the universal joint from being bent at a steep angle. A valve mechanism is arranged between both front wheel support frames as close as possible to the inner surface side of the front wheel support frame, and the valve mechanism and power cylinder are connected in the vicinity of the end side where the cylinder port of the valve mechanism is located. As much piping space as possible can be secured.
[0009]
〔effect〕
Therefore, although the all-hydraulic power steering device is adopted, the power steering device can be driven and lightly operated while no noise is generated or is hardly generated in the driving unit.
On the other hand, the valve mechanism is superior in terms of durability so that it is guarded by the wheel support frame and is not easily damaged or damaged. Furthermore, when the valve mechanism and the power cylinder are connected by a hydraulic hose, the connection work can be easily performed while minimizing the elastic restoring force.
In addition, as much piping space as possible is secured near the end where the cylinder port of the valve mechanism is located, and the work for connecting the valve mechanism and the power cylinder can be easily performed in as much space as possible.
[0010]
Construction of the invention according to Claim 2 is as follows.
[0011]
〔Constitution〕
In the configuration of the invention according to claim 1, after the power cylinder is disposed in front of the front axle member, the hydraulic hose extends forward from the cylinder port of the valve mechanism, and is bent between the pair of left and right front wheel support frames. Connected to the power cylinder.
[0012]
[0013]
[0014]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, a pair of left and right steering and driveable front wheels 1, a pair of left and right driveable rear wheels 2, a prime mover having an engine 3 positioned between the left and right front wheels 1, and the rear of the prime mover A pair of left and right lift arms 6 are attached to a rear transmission case 11 constituting a body frame of a self-propelled vehicle body having a steering section 4 and a driving section 5 having a driving seat 5. A pair of lift cylinders 7 that are separately connected on the rod side, both the base ends of the lift arms 6 are pivoted around the axis of one rotary support shaft 8 that is rotatably connected to the rear transmission case 11. The lift arm 6 is configured to swing up and down, and a power take-out shaft 9 is provided at the rear end of the rear mission case 11 to constitute a tractor.
[0015]
The tractor connects various working devices such as a rotary tiller to the rear of the vehicle body by the pair of lift arms 6 so as to be movable up and down, and transmits the driving force of the engine from the power take-off shaft 9 to the connected working devices. Thus, various riding-type work devices such as a riding-type tillage device are configured.
[0016]
As shown in FIG. 1, the engine 3, a clutch housing 12 having a front end connected to the rear part of the engine 3, a transmission case 13 having a front end connected to the rear part of the clutch housing 12, and a rear end part of the transmission case 13 The rear transmission case 11 connected to the front end side, as shown in FIG. 5, a pair of left and right front wheel support frames 14 extending from the lateral sides of the lower part of the engine 3 toward the front of the vehicle body, and the pair of left and right front wheels. Each of the connecting frames 15 connecting the front end portions of the support frame 14 constitutes a vehicle body frame. As shown in FIGS. 2, 4 and the like, the front wheel support case 20 with the left front axle 1a rotatably attached to the lower end side is attached to one end side, and the right front axle 1a is attached to the lower end side. The pair of left and right front wheels 1 are operated around the steering axis X by supporting the upper end side of the front wheel support case 20 on the other end so as to be rotatable around the steering axis X in the vertical direction of the vehicle body. A pair of front and rear provided in the middle part of the front axle member 21 comprising a front wheel drive case that is supported in a freely movable manner and that includes a rotating shaft and a front wheel differential mechanism for transmitting power to the left and right front axles 1a. Are connected to a pair of front and rear shaft support portions 24 provided in a support member 23 that is connected across the middle portion of the pair of left and right front wheel support frames 14 around the same rolling axis P in the vehicle longitudinal direction. It is pivotably connected.
[0017]
As a result, the pair of left and right front wheels 1 steer the vehicle body by swinging around the steering axis X relative to the vehicle body frame in a straight direction, left direction, or right direction, and steer the vehicle body to the ground. Even if there is unevenness or left-right inclination, the vehicle body is swung up and down around the rolling axis P with respect to the vehicle body frame to maintain the vehicle body in the horizontal or horizontal posture in the left-right direction.
[0018]
As shown in FIG. 3, the left and right front wheels 1 have a power cylinder 31 including a power cylinder 31 in which a cylinder tube 31 a is fixed across a pair of left and right cylinder support portions 25 provided on the front side of the front axle member 21. A steering operation is performed by the steering device 30. The power steering device 30 will be described in further detail as follows.
[0019]
That is, in addition to the power cylinder 31, the power steering device 30 is disposed in front of the front axle member 21 and between the pair of left and right front wheel support frames 14, as shown in FIG. In addition, one end side of the casing 33 is fixed to a valve support member 27 that extends from the inner surface side of one front wheel support frame 14, and is fixed to a side portion of the engine 3 and transmits power from the engine 3. And a main pump 37 configured to be driven.
[0020]
As shown in FIG. 2 and the like, the power cylinder 31 is configured as a double rod type hydraulic cylinder provided with a single cylinder rod 31b protruding from both ends of the cylinder tube 31a. One end side of the cylinder rod 31b of the power cylinder 31 is connected to the operation portion 20a provided on the upper end side of the front wheel support case 20 of the left front wheel 1 by a connecting pin 31c so as to be relatively rotatable. The other end side of 31b is connected to the operation part 20a provided on the upper end side of the front wheel support case 20 of the right front wheel 1 by a connecting pin 31c so as to be relatively rotatable. A portion of the power cylinder 31 that protrudes from the cylinder tube 31 a of the cylinder rod 31 a is surrounded by a rod cover 28 that is fixed to the front axle member 21 so that stones and soil blocks do not easily hit.
[0021]
As shown in FIG. 5, the valve mechanism 32 includes a control valve 34 having a pair of cylinder ports 34 a and an input port 34 b located at one end of the casing 33, and the cylinder port 34 a of the casing 33. And an input shaft 35a protruding at the end opposite to the side where the input port 34b is located, and a metering pump 35 connected to the control valve 34 inside the casing 33. The valve support member is arranged in such a state that the pair of cylinder ports 34a open in a direction obliquely forward with respect to the vehicle body, and the input shaft 35a protrudes in a direction obliquely rearward with respect to the vehicle body. 27.
[0022]
The pair of cylinder ports 34a of the valve mechanism 32 is a pair of input / outputs distributed to both ends of the cylinder tube 31a of the power cylinder 31 by a pair of hydraulic hoses 38 made of flexible and pressure-resistant rubber. The input port 34b of the valve mechanism 32 is connected to the discharge port of the main pump 37 through an oil supply passage 39 made of a metal pipe.
[0023]
As shown in FIGS. 5, 6, and 7, the input shaft 35 a of the valve mechanism 32 is supported by a joint 41 that is rotatably supported by a cylindrical portion 27 a of the valve support member 27 via a bearing 27 b. A valve-side rotation shaft portion 42 is connected to the input shaft 35a so that one end side thereof is integrally rotatable and the other end side protrudes laterally outside the vehicle body frame through the through hole 14a of the one wheel support frame 14. The rotating shaft 40 is connected to the steering handle 4.
[0024]
The rotary shaft 40 is connected to the valve-side rotary shaft portion 42 and an end portion of the valve-side rotary shaft portion 42 located outside the vehicle body frame by a universal joint 43 so that the front end side can be integrally rotated. An intermediate rotating shaft portion 44 that extends along the longitudinal direction of the vehicle body on the outer side, and one end side of the intermediate rotating shaft portion 44 is connected to the rear end side of the intermediate rotating shaft portion 44 by a universal joint 43 so as to be integrally rotatable. It is comprised by the handle side rotating shaft part 45 connected with the lower end side of the axis | shaft 4a so that integral rotation is possible.
[0025]
As a result, when the power steering device 30 rotates the steering handle 4, the left and right front wheels 1 are moved in the steering direction equal to the operation rotation direction of the steering handle 4 by the driving force of the power cylinder 31. The steering operation is performed by an angle corresponding to the operation rotation angle.
That is, when the steering handle 4 is rotated, this turning force is transmitted to the input shaft 35a of the valve mechanism 32 by the rotating shaft 40, the metering pump 35 is driven, and the control valve 34 of the valve mechanism 32 is operated to the oil supply side. Then, the pressure oil supplied from the main pump 37 via the oil supply passage 39 is supplied to the power cylinder 31 via the hydraulic hose 38. Then, the power cylinder 31 is driven by the pressure oil from the valve mechanism 32 to swing the front wheel support case 20 by swinging the operation portions 20a of the left and right front wheel support cases 20 around the steering axis X. By operating, the left and right front wheels 1 are steered by an angle corresponding to the rotation angle of the steering handle 4 in a direction equal to the operation direction of the steering handle 4. When the rotation operation of the steering handle 4 is stopped, transmission from the steering handle 4 to the input shaft 35a of the valve mechanism 32 is stopped, the metering pump 35 is stopped, and the control valve 34 of the valve mechanism 32 is on the oil supply stop side. Then, the supply of pressure oil to the power cylinder 31 is stopped. Then, the power cylinder 31 stops the left and right front wheels 1 in the steering direction corresponding to the operation position of the steering handle 4 by stopping the swinging operation of the left and right front wheel support cases 20.
[0026]
A hydraulic circuit for operating the pair of lift cylinders 7 is configured as shown in FIG.
[0027]
That is, the first control valve 52 connected to the pair of lift cylinders 7 via the cylinder-side oil supply passage 51 provided with the check valve 50 is connected to the hydraulic pump 54 via the pump-side oil supply passage 53. It is. A second control valve 57 connected to the cylinder side oil supply passage 51 between the cylinder 7 and the check valve 50 via a cylinder side oil discharge passage 56 having a drop adjustment valve 55 is provided on the tank side. The oil drain path 58 is connected.
[0028]
That is, the drop adjustment valve 55 is switched to the open side by rotating the operation knob 59 disposed below the front end side of the driver seat 5 in conjunction with the operation portion of the drop adjustment valve 55. Then, when the first control valve 52 is switched to the raised position, the second control valve 57 is switched to the closed position in conjunction with this, and the pressure oil from the hydraulic pump 54 is paired by the cylinder- side oil supply passage 51. is supplied to the lift cylinder 7, both the lift cylinder 7 is driven on the side of the raised operating the lift arm 6. When the first control valve 52 is switched to the lowered position, the second control valve 57 is switched to the open position in conjunction with this, and the pair of lift cylinders 7 are cylinder-side oil drain passages due to the weight of the work device. The pressure oil is discharged from 56 to the tank side drain oil 58, and the lift arm 6 is operated to the lowering operation.
[0029]
By operating the drop adjustment valve 55 in the closed state by rotating the operation knob 59, the operation of the pair of lift cylinders 7 due to oil leakage can be prevented, and the connected working devices can be prevented from falling.
[0030]
A hydraulic pressure take-out port 60 is provided for supplying hydraulic pressure to the connected working devices. The hydraulic pressure take-out port 60 is connected by an oil passage 61 between the drop adjustment valve 55 and the second control valve 57 of the cylinder-side oil discharge passage 56, and the non-returning of the cylinder-side oil supply passage 51. Connected between the valve 50 and the first control valve 52.
Accordingly, even if the drop adjustment valve 55 is kept switched to the closed state, the hydraulic actuator connected to the hydraulic pressure take-out port 60 can be switched by switching the first control valve 52 and the second control valve 57. Can be operated.
[Brief description of the drawings]
[Fig. 1] Side view of the entire tractor [Fig. 2] Front view of the front wheel support structure [Fig. 3] Plan view of the front wheel support structure [Fig. 4] Side view of the support structure of the front axle member [Fig. FIG. 6 is a cross-sectional view showing a connecting structure of a valve mechanism input shaft and a rotary shaft. FIG. 7 is a schematic diagram of a power steering device. FIG. 8 is a hydraulic circuit diagram for a lift cylinder.
DESCRIPTION OF SYMBOLS 1 Front wheel 3 Engine 4 Steering handle 14 Front wheel support frame 14a Through-hole 21 Front axle member 30 Power steering apparatus 31 Power cylinder 32 Valve mechanism 34a Cylinder port 35a Input shaft
38 hydraulic hose
43 universal joints
44 intermediate rotation shaft

Claims (2)

An axle member before supporting a pair of right and left front wheels freely steered, rolling freely supported on a pair of left and right front wheel supporting frame extending in the vehicle body forward-looking from the engine and steering operating the pair of front wheels a tractor that is supported on the front axle member power cylinder of the total hydraulic type power steering system,
A valve mechanism for operating the power cylinder is positioned in front of the front axle member and between the pair of left and right front wheel support frames ;
The cylinder port of the valve mechanism opens obliquely forward with respect to the vehicle body, and the input shaft of the valve mechanism is obliquely rearward with respect to the vehicle body from the end opposite to the side where the cylinder port is located. The valve mechanism so as to protrude toward
From the steering handle, an intermediate rotation shaft portion extends forward along the outer surface side of the front wheel support frame, and a universal joint is connected to the front end side of the intermediate rotation shaft portion, so that the universal joint and the valve mechanism The input shaft is linked and connected through the through hole of the front wheel support frame,
Connecting the cylinder port of the valve mechanism and the power cylinder via a hydraulic hose;
A tractor in which the pair of left and right front wheel support frames are linearly formed in a plan view across the front and rear at a position where the valve mechanism is disposed . While placing the power cylinder in front of the front axle member,
2. The tractor according to claim 1, wherein a hydraulic hose extends forward from a cylinder port of the valve mechanism and is bent between a pair of left and right front wheel support frames and then connected to a power cylinder .

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