JPS628225Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a steering device installed in a traveling work vehicle such as a four-wheel drive riding rice transplanter, and is designed to shorten the longitudinal length of the machine when the vehicle turns, thereby reducing the turning radius. The present invention provides a novel steering device that achieves the following.

A technique for reducing the body length of a traveling working vehicle for making small turns is already known as disclosed in Japanese Patent Publication No. 47-21764. In the above-mentioned publication, an extendable portion is provided in a body portion that supports the non-drive side wheels of a two-wheel drive traveling work vehicle. Additionally, reduction of the fuselage length is to be carried out as an independent operation prior to the vehicle turning.

The purpose of this invention is to adopt a structure that allows the body length to be extended and contracted for making small turns in a four-wheel drive traveling work vehicle.
The extendable part of the fuselage and the extendable part of the wheel drive power transmission system guide each other to achieve stable extension and contraction without twisting, and the length of the fuselage is reduced in conjunction with the operation when the vehicle turns. To provide a new steering device for a riding rice transplanter, etc., which ensures a desired reduction in the length of the machine and eliminates the need for a special operation to reduce the length of the machine.

Regarding the illustrated embodiment, to explain the structure of the steering device for a riding rice transplanter, etc. according to this invention, this embodiment is based on an example in which this invention was implemented in a riding rice transplanter as shown in FIG. It depends. This riding rice transplanter has two parts, 1 in the front part of the machine and 2 in the rear part of the machine.
The machine is divided, and the left and right front wheels 3 are installed in the front part 1 of the machine, and the left and right rear wheels 4 are installed in the rear part 2 of the machine, respectively.
A passenger seat 5 and an engine 6 are arranged vertically at the rear of the front part 1 of the fuselage, and the front and rear parts of the fuselage 1 and 2 are connected so as to be relatively rotatable around a vertical fulcrum shaft 7, so that the front passenger seat 5 is arranged vertically. The front part 1 of the fuselage is controlled by the control handle 8.
The aircraft is steered by swinging the rear part 2 of the aircraft relatively, that is, by swinging the left and right rear wheels 4 integrally. They are connected by a rotatable connecting device 9, and are provided with a planting section 13 having a seedling stand 10, planting claws 11, a float 12, and the like. In addition, in this riding rice transplanter, the engine 6
The power of After changing gears using a traveling power transmission device (not shown), the power is transmitted to the front wheels 3 and rear wheels 4 to allow the aircraft to travel by four-wheel drive. After changing the speed using a transmission device (not shown), the flexible transmission shaft mechanism 1 is connected to the PTO shaft 16 that can be extended forward to the front part of the fuselage 1.
The power is transmitted to the planting section 13 via 7, which drives the seedling stand 10 of the planting section 13 in a horizontal reciprocating manner and the planting claws 11.
It is designed so as to perform rotational driving.

As shown in FIG. 2, the power transmission mechanism from inside the mission case 15 to the rear wheel 4 includes a power transmission shaft 18 that transmits power from inside the mission case 15 to the rear, and a flexible joint placed at the fulcrum shaft 7 position. A transmission shaft 20 is interlocked and connected to the transmission shaft 18 by a transmission shaft 19, and a transmission shaft 21 is connected to the transmission shaft 20 by a connecting means as described later. At the rear end of the rear part 2 of the aircraft are left and right rear wheels 4.
A differential housing 23 that accommodates a differential device 22 for
As shown in FIGS. 2 and 3, the left and right output shafts 22b of the differential gear 22 receive input by meshing the bevel gear 24 at the end of the transmission shaft 21 with the input bevel gear 22a. The final gears 25 and 26 are interlocked and connected to the left and right rear wheel axles 4a via a reduction gear, completing a power transmission path to the left and right rear wheels 4, and the transmission shafts 20 and 21 are covered with a covering tube 27. and the differential output shaft 22b and the final gear 25,
The 26 speed reducer is housed in left and right casings 28 that are fixedly supported by the differential housing 23.

As described above, the rear part 2 of the fuselage is divided into two parts as follows and can be expanded and contracted in a telescopic manner. That is, as shown in FIG. 2, at the front end of the rear part 2 of the fuselage, there is a pair of upper and lower support cylinders 29 that support the fulcrum shafts 7 that are fixed to the front part 1 of the fuselage. Cylindrical body 30 welded and fixed to
The distal end of the covering tube 27 is slidably inserted into the support tube 30a, which forms the rear end of the cylinder 30 and has a smaller diameter than the front end. On the other hand, by relatively moving the covering tube 27 back and forth, the rear part 2 of the fuselage can be expanded and contracted in a telescopic manner. In order to transmit power between the power transmission shafts 20 and 21 while making this expansion and contraction possible, as shown in FIG. A cylinder 31 is provided, and a spline 20a is formed over a certain length at the rear end of the transmission shaft 20, and the transmission shaft 20 is fitted with the splines 20a and 31a to the spline cylinder 31, thereby making the transmission shafts 20 and 21 relative to each other. Although not rotatable, they are slidably connected.

As shown in FIG.
4, a hydraulic cylinder 36 is disposed in the rear part 2 of the fuselage along the longitudinal direction of the fuselage.
The rear part 2 of the fuselage is expanded and contracted by obtaining relative back and forth movement between the cover tube 27 and the cover tube 27. The hydraulic circuit for expanding and contracting the hydraulic cylinder 36 is as follows:
As shown in FIG. 4, an oil supply circuit 39 runs from the oil tank 37 to the hydraulic cylinder 36 via the hydraulic pump 38, and from the oil tank 36 from the hydraulic cylinder 36.
A switching valve 41 as shown in the figure, that is, an oil supply circuit 39 is inserted and connected to the oil drain circuit 40 leading to No. Extension operation position 1 connects to the oil drain circuit 40 to extend the hydraulic cylinder 36, and connects the oil supply circuit 39 to the reduction operation oil chamber 36b of the hydraulic cylinder 36 and drains the extension operation oil chamber 36a of the cylinder 36. A switching valve 41 is provided which is connected to the circuit 40 and has a reduction operation position for causing the hydraulic cylinder 36 to perform a reduction operation. A pressure regulating valve 42 for setting the oil pressure applied to the hydraulic cylinder 36 is inserted between the oil supply circuit 39 and the oil drain circuit 40. The switching valve 41 is
The spool is displaced and biased by a compression spring 43, so that it normally assumes the above-mentioned extension position. Therefore, the hydraulic cylinder 36
is always maintained at its maximum extension, so that the front and rear sections 1 and 2 of the fuselage are always maintained at their maximum extension.

The switching valve 41 is moved to the reduction position by the following mechanism.
That is, in FIG. 1, reference numeral 44 denotes a reduction gearbox at the lower end of the handle shaft of the control handle 8, and a pitman arm 45 on the output shaft of the gearbox 44 is connected to two directions at the rear of the aircraft via a drag rod 46, and is connected to the steering wheel. Although the mechanism has been completed, as schematically shown in FIG. 4, between the operating lever 41a of the switching valve 41 and the above-mentioned pitman arm 45, both ends of the outer wire 47a are fixed to appropriate positions on the machine body, and the inner wire 47b is connected to the operating lever 41a of the switching valve 41. An operating cable 47 is provided which is fixed at both ends to the operating lever 41a and the pitman arm 45. As is clear from FIG. 4, when the control handle 8 is rotated almost fully in one direction or the other direction, and the Pittman arm 45 is rotated almost fully in one direction or the other direction, the inner wire 47b is tensioned. At this time, the operating lever 41a is moved by the spring 4.
The spool of the switching valve 41 is displaced in the position direction against the three forces, thereby displacing the switching valve 41 to the reduction position.

Therefore, in order to turn the aircraft, the control handle 8
When the switch is rotated in one direction or the other, the switching valve 41 is automatically displaced from position to position in conjunction with this, and the hydraulic cylinder 36 is compressed to reduce the distance between the front and rear parts of the fuselage 1 and 2. The space between the front and rear wheels 3 and 4, that is, the wheelbase, is reduced, allowing the aircraft to turn with a small turning radius. After this turn, when the control handle 8 is rotated in the opposite direction to return the pitman arm 45 to its original position, the switching valve 41 is returned to the extended position by the force of the spring 43 due to the relaxation of the inner wire 47b, and the hydraulic cylinder 36 is It is extended to the stroke end, and the space between the front and rear parts 1 and 2 of the fuselage is extended again. In this state, where the front and rear parts 1 and 2 of the fuselage are extended to increase the wheelbase, the fuselage is stabilized and a stable running condition can be obtained.

In FIG. 2, reference numeral 48 denotes a support tube fixed to the differential housing 23 and inserted into the cover tube 27. It is supported by the covering tube 27 so as to be able to swing freely. The transmission shaft 21 is supported by this support cylinder 48 . In FIG. 1, 49 is a hydraulic lift arm for raising and lowering the planting section 13, and 50 is a preliminary seedling stand installed above and behind the passenger seat 5.

In the above embodiment, the extensible aircraft was configured to contract in conjunction with the turning operation of the aircraft, but it is possible to contract the aircraft for the purpose of making a small turn using other methods. It is a good thing to wear. FIG. 5 shows another embodiment in which the aircraft body is reduced in the following manner. That is, in this other embodiment, a four-port, two-position switching valve 41' similar to the switching valve 41 is
The solenoid switching valve is configured as an electromagnetic switching valve that normally assumes an extension position with the bias of a spring 43 and is moved to a contraction position with the excitation of a solenoid 41b. a PTO clutch (not shown) that starts and stops driving the planting section 13 by intermittent power transmission to the PTO shaft 16;
The clutch lever 51 and the solenoid 41b are connected so that the solenoid 41b is energized by operating the PTO clutch lever 51 in the clutch disengaging direction. That is, as shown in FIG. 5, a switch 52 is provided which is turned on when the PTO clutch lever 51 is in the clutch disengaged position shown by the chain line, and this switch 52 is connected to the solenoid 41b via a power source 53 and a power switch S. There is. Therefore, in this other embodiment, when the PTO clutch is disconnected to stop the driving of the planting section 13 prior to turning the aircraft at the edge of a ridge, the electromagnetic switching valve 41' is automatically moved to the reduction position. The space between the front and rear parts 1 and 2 of the aircraft is displaced, and the space between the front and rear parts 1 and 2 of the aircraft is reduced, and a small turn is made during the next aircraft turn.Then, when the PTO clutch is engaged again, the electromagnetic switching valve 41' becomes extended again. Automatically assumes position and automatically extends the aircraft.

As described above, this invention is configured to reduce the size of the aircraft in conjunction with operations during aircraft rotation, such as aircraft rotation and planting section drive stop operations. As for the operation,
There is a valve operation for raising and rotating the hydraulic lift arm 49 to lift the planting section 13.
Further, in the above embodiment, the airframe expansion and contraction was obtained by the hydraulic cylinder 36, but such airframe expansion and contraction can also be obtained by mechanical means such as a reciprocating spring, and in this case, For example, rotation of the feed screw may be obtained by a clutch that automatically engages when the aircraft turns.

As is clear from the above description, the steering device of this invention is used in traveling working vehicles such as four-wheel drive riding rice transplanters, and is equipped with a power transmission shaft that is installed along the longitudinal direction of the machine and transmits power to the front or rear wheels. The transmission case, which is part of the interior and also forms part of the fuselage, is divided into two parts: front and rear.
The transmission case is divided into case parts 30 and 27, and the two case parts 30 and 27 are telescoped and telescopically fitted together, and the transmission shaft is divided into two front and rear shaft parts 20 and 21 within the transmission case. The two shaft parts 20 and 21 are fitted and connected so that they are relatively slidable but not relatively rotatable (the spline connection in the embodiment may be replaced by a slide key connection), and are interlocked with operations when the aircraft turns. A telescopic driving means 36 is provided for contracting the body between the two case parts 30 and 27, and the following effects are achieved.

In other words, this idea is a four-wheel-drive traveling work vehicle, and in order to adopt a structure that can reduce the length of the machine body, it is a two-part transmission case that houses a transmission shaft that transmits the expansion and contraction of the machine body to one of the front and rear wheels 4. The fitting structure of the parts 30 and 27 is used to provide an elastic part to be provided in the transmission system of the wheel driving force by fitting the two divided shaft parts 20 and 21 of the transmission shaft in the transmission case. Because of the mating connection structure, the expansion and contraction of the transmission cases 30 and 27 and the expansion and contraction of the transmission shafts 20 and 21 are performed in a mutually guiding relationship, and the airframe is adjusted based on the expansion and contraction of the transmission cases 30 and 27. In addition, the expansion and contraction of the transmission system based on the expansion and contraction of the transmission shafts 20 and 21 is also performed stably without any twisting, thereby ensuring smooth expansion and contraction and prevention of member damage over a long period of time. do. In addition, the telescopic parts 20, 2 of the power transmission shaft are inside the telescopic parts 30, 27 of the fuselage.
1, these two types of telescopic parts can be assembled at the same time, making assembly easy.

In addition, this invention reduces the size of the fuselage or fuselage section 2 in conjunction with the operation performed when the vehicle turns, so it is possible to reliably reduce the fuselage length for a tight turn, and there is no need for a special fuselage length reduction operation. shall be.

[Brief explanation of the drawing]

Fig. 1 is a side view of a riding rice transplanter equipped with an embodiment of this invention, Fig. 2 is a vertical cross-sectional side view of the main parts of the riding rice transplanter, and Fig. 3 is a longitudinal cross-section of other main parts of the riding rice transplanter. A front view, FIG. 4 is a circuit diagram/mechanism diagram showing a hydraulic circuit and a mechanism in the same embodiment, and FIG. 5 is a circuit diagram/mechanism diagram showing a hydraulic circuit, an electric circuit, and a mechanism in another embodiment. It is. 1... Front part of the fuselage, 2... Rear part of the fuselage, 3... Front wheel, 4... Rear wheel, 7... Vertical fulcrum shaft, 8... Control handle, 20, 21... Transmission shaft, 20a... Spline, 27...Coated cylinder, 30...Cylinder body, 30
a...Support cylinder part, 31...Spline cylinder, 36...
... Hydraulic cylinder, 41 ... Switching valve, 41a ... Operation lever, 43 ... Compression spring, 45 ... Pitman arm, 47 ... Operation cable, 47b ...
Inner wire, 41'...Solenoid switching valve, 41b...
...Solenoid, 51...PTO clutch lever,
52...Switch, 53...Power supply.

Claims (1)

[Scope of utility model registration request] In a traveling work vehicle such as a four-wheel-drive riding rice transplanter, the transmission case, which is installed along the longitudinal direction of the machine and transmits power to the front or rear wheels, is installed inside the machine and forms a part of the machine. Divided into two case parts 30 and 27, the two case parts 3
0 and 27 telescopically telescopically fitted together, and the transmission shaft is divided into two front and rear shaft parts 20 and 21 within the transmission case, and the two shaft parts 2
0 and 21 are fitted and connected in a relatively slidable but non-rotatable manner, and are provided with a telescopic drive means 36 for contracting the body between the two case parts 30 and 27 in conjunction with operations when the body turns. , steering devices for riding rice transplanters, etc.