JPH0542652Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a four-wheel drive switching device that can be applied to mobile agricultural machinery such as agricultural tractors.
This relates to a four-wheel drive switching device for a mobile agricultural machine that applies a biasing force to the clutch input side in the direction of pressing a ball when the clutch is operated beyond the intermediate position between the ON and OFF positions. .

[Prior art]

For four-wheel drive type agricultural tractors, a four-wheel drive switching device for switching between a normal two-wheel drive state in which only the rear wheels are driven and a four-wheel drive state in which the rear wheels and front wheels are simultaneously driven. is equipped with.

[Problem that the invention attempts to solve]

Conventionally, a gear slide system has been adopted as this 4-wheel drive switching device, but with this gear slide system, the aircraft cannot be switched to 4-wheel drive mode unless the main clutch is operated to stop the aircraft.
There was a problem that it was difficult to operate.

There is also a hydraulic clutch system as another four-wheel drive switching device that switches to four-wheel drive mode while driving, but this system requires a hydraulic clutch, which increases manufacturing costs and increases production costs. There was a problem that the structure became complicated.

Therefore, in view of the conventional situation mentioned above, the present invention is
This system was devised to solve this problem, and by operating the switching lever to the clutch inlet side beyond the intermediate position between ON and OFF positions, the sleeve is energized by a toggle spring. The purpose of this invention is to provide a four-wheel drive switching device for a mobile agricultural machine that can switch to a four-wheel drive state even while traveling by applying a biasing force in the direction of pressing the vehicle.

[Means to solve the problem]

The present invention achieves the above object by rotatably disposing a drive gear driven by the drive shaft of the running system that drives the rear wheels on the front wheel drive shaft, and having a ball interposed between the drive gear and the front wheel drive shaft. A sleeve for connecting and disconnecting the ball clutch is slidably provided on the clutch, and a switching lever engaged with the sleeve via a fork is pivotally supported on the machine body so as to be swingable. Attach one end of the spring to the switching lever side and the other end to the aircraft side, and then extend the switching lever when the fixing point of the toggle spring on the aircraft side faces the switching lever to the intermediate position M between the OFF and ON positions. When the switching lever is positioned on the line and the switching lever is operated to the clutch entry side beyond the intermediate position M, the sleeve is biased by the toggle spring, and the large diameter portion where the ball of the ball clutch provided on the sleeve does not act. The present invention is characterized in that the ball can be moved in a direction in which the ball is pressed toward the front wheel drive shaft by a working slope formed continuously with the front wheel drive shaft.

[Effect]

Therefore, the drive gear 39 driven from the drive shaft 30 of the running system that drives the rear wheels 6 is connected to the front wheel drive shaft 3.
7, and a ball clutch mechanism 50 is interposed between the drive gear 39 and the front wheel drive shaft 37.
A sleeve 43 for intermittent 0 is slidably provided in conjunction with a switching lever 45 energized by a toggle spring 49 for switching the clutch between the engaged and disengaged states. In addition, when the switching lever is moved beyond the intermediate position between the ON and OFF positions to the clutch inlet side, the biasing force of the spring is used to constantly press the ball toward the front wheel drive shaft. In addition, even when driving in 2WD, the switching lever 45
By simply operating the ball clutch mechanism 50 into the engaged state, the toggle spring 49 that biases the engaged state generates a sufficient load on the sleeve 43 to turn the ball clutch mechanism 50 into the engaged state. When synchronization is achieved, the switching lever 45 and the sleeve 43 are automatically moved to bring the ball clutch mechanism 50 into the engaged state.

Thereby, the drive gear 39 driven from the drive shaft 30 of the running system that drives the rear wheels 6 and the front wheel drive shaft 3 are connected to each other.
Although it has a simple structure in which a ball clutch mechanism 50 is interposed between the main clutch 3 and the clutch 7, it is possible to switch to a 4-wheel drive state without operating the main clutch 3 during 2-wheel drive running.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings as an embodiment thereof.

As shown in FIG. 7, the agricultural tractor T has an engine 2 covered by a bonnet 1 at the front of the machine body, and the front part of a transmission case 4 extending rearward is connected and fixed to the rear of the engine 2. , these engine 2 and transmission case 4 constitute a monokotsuk vehicle body 5 of an agricultural tractor.

Axle cases 7 supporting axles to which rear wheels 6 are attached are attached to both rear sides of the transmission case 4, and chassis 9 whose base ends are fixed to both sides of the engine 2 face forward. A front wheel case having left and right front wheels 10 is fixed below the chassis 9.

A steering wheel 11 for steering the front wheels is provided behind the bonnet 1, and a driver's seat 12 is provided behind the steering wheel 11. A lift arm 15 is fixed to the upper surface of a hydraulic cylinder 13 fixed above, and is provided behind the hydraulic cylinder 13 to move up and down about a fulcrum shaft 14 .

A working machine such as a rotary tiller is attached to the lift arm 15 via a three-point linkage mechanism (not shown) or the like.

A main clutch 3 connected to the flywheel of the engine 2 is provided in front of the transmission case 4. When a clutch pedal 16 provided on the case 4 side is depressed, the main clutch 3 is brought into the clutch disengaged state and restored. The clutch is engaged when the clutch is engaged.

As shown in FIG. 5, the clutch petal 16 includes:
A safety switch 1 constitutes a starting safety circuit that can start the engine 2 only when the main clutch 3 is disengaged.
7 are arranged opposite to each other, and this safety switch 17 is fixed to the side surface of the case 4 with a fixing metal fitting 19.

A clutch petal 16 swings between a solid line state and a chain line state around a fulcrum shaft 20, and a release plate 2 swings around a fulcrum shaft 21.
2 are interlocked and connected to each other by a connecting rod 23. By providing a pressing concave surface 22a above the fulcrum shaft 21 of the release plate 22 for pressing the knob 17a of the safety switch 17 to the ON state, the knob 17a is pushed in a distance H.
Contact surface 2 that comes into contact with the top surface of the safety switch 17 and prevents it from being pushed further when the switch is turned on.
2b is formed. This configuration eliminates the need for the fixing metal fitting 23a fixed to the side surface of the case 4 and the adjustment bolt 24 locked to the fixing metal fitting 23a, as in the conventional case.

As shown in FIG. 4, inside the transmission case 4 is a variable displacement pump (variable displacement reversible swash plate pump) whose speed can be changed steplessly by changing the angle of the movable swash plate and changing the discharge amount of the pump. A hydraulically driven continuously variable transmission mechanism 26 (HST) is fixed, and the input shaft 2 of this hydraulically driven continuously variable transmission mechanism 26 is
6a and the main clutch 3 are interlocked and connected by a main shaft 25 extending in the front-rear direction. This hydraulic drive continuously variable transmission mechanism 26 has an upper output shaft 2.
6b and a lower output shaft 26c protrude.

This upper output shaft 26b extends rearward.
It is interlocked and connected to a PTO system transmission shaft 27, while a transmission gear 29 is fixed to the lower output shaft 26c. This transmission gear 29 is interlocked and connected to a transmission gear 31 fixed on a drive shaft 30 of the travel system via a gear fixed to a counter shaft (not shown). A gear 32 fixed on the drive shaft 30 meshes with a gear 34 on the rear wheel drive shaft 33, so that the rear wheel drive shaft 33 is driven from the drive shaft 30. A gear 35 fixed to the rear wheel drive shaft 33 is meshed with an idling gear 36 positioned so as to be freely rotatable on the drive shaft 30, and this idling gear 36 is freely rotatably positioned on the front wheel drive shaft 37. It is meshed with a drive gear 39 positioned at . Further, the front part of this front wheel drive shaft 37 is interlocked and connected to a front wheel drive take-out shaft 40 that extends forward, and this front wheel drive take-out shaft 40 is interlocked and connected to an input shaft provided in the front wheel case via a connecting shaft 41. has been done.

The rear wheels 6 are driven by a pinion gear 33a integrally formed at the rear end of the rear wheel drive shaft 33 meshing with a large differential gear constituting a differential gear (not shown). It is becoming more and more like this.

As shown in FIG. 1, a guide tube 39a extending forward is integrally formed with the drive gear 39, and a sleeve 43 is slidably fitted around the outer periphery of the guide tube 39a. Further, as shown in FIG. 3, a fulcrum shaft 44 is rotatably positioned on the side wall 4a of the case 4 in a direction perpendicular to the axial direction of the front wheel drive shaft 37. The base end side of a shift fork 44a whose tip fits into the groove of the sleeve 43 is fixed, and the base end side of a switching lever 45 pointing upward along the side wall 4a is fixed to the outside of this fulcrum shaft 44 by a knock pin 45a. ing. A spring 49 configured as a toggle spring is tensioned between the locking tool 46 fixed outwardly to the switching lever 45 and the locking bolt 47 screwed into the case 4 as the switching lever 45 moves. It is set up.

As shown in FIG. 1, the front wheel drive shaft 37 is provided with ball holes 51a at positions where the outer periphery is divided into a plurality of equal parts (four equal parts in the drawing), and the outer periphery of the guide cylinder 39a of the drive gear 39 is also provided with a ball hole 51a. Equally divided into multiple parts (4 in the drawing)
Ball guide holes 51b are provided at the positions where the sleeves 43 are equally divided, and each ball 51 is fitted into both of the ball holes. A ball clutch mechanism 50 is provided which can be operated alternatively between a clutched state in which each ball 51 is pressed by movement, or a clutched state in which each ball 51 is not pressed by movement of the sleeve 43 to the OFF side. There is.

A large diameter portion 52 is formed on the inner diameter side of the sleeve 43 and has a larger diameter than the outer diameter of the guide tube 39a so as to maintain the clutch in the disengaged state without pressing the ball 51. Large diameter part 5
An operating inclined surface 53 is formed between the inner diameter portion of the sleeve 43 and the inner diameter portion of the sleeve 43 .

The switching lever 45 moves around the fulcrum shaft 44 over a range between the off position (OFF) and the on position (ON) of the ball clutch mechanism 50, and at an intermediate position M of this movement range, the operating lever 45 The locking bolt 47 is provided on the extension line of , and the biasing force of the spring 49 at this intermediate position M maintains a neutral state, but is switched to either the ON position side or the OFF position side. When the lever moves, it acts as a toggle spring that acts on the side it moves to.

Then, the switching lever 45 moves a distance F to the off position and a distance N to the on position, centering on the intermediate position M, but with this movement, the shift fork 44a moves a distance f to the off position and a distance n to the on position. Configured to move.

Therefore, when the switching lever 45 is manually operated to the ON side beyond the intermediate position M, the switching lever 45 is biased to the ON side by the toggle spring 49.
Move the sleeve 43 to the rear side,
The ball 51 is moved in a direction perpendicular to the shaft center along the action inclined surface 53, and the front wheel drive shaft 37, the drive gear 39, and the ball 51 are integrated, and the input to the drive gear 39 can be transmitted to the front wheel drive shaft 37. . As a result, the front wheels 10 and the rear wheels 6 are simultaneously connected to the drive shaft 3 of the traveling system.
The vehicle is driven from zero and switched to four-wheel drive mode.

At this time, the sleeve 43 corresponds to the movement range of the switching lever 45 where the force applied to the ON side of the sleeve 43 by the toggle spring 39 becomes the specified load.
During the movement amount n, the sleeve 43 has a large diameter portion 52 that does not act on the ball 51, an action inclined surface 53 that gradually presses the ball 51 in the ON direction beyond the intermediate position M of the switching lever, and a ball 51 in the ON state. 51
An inner diameter portion is configured to maintain the closed state. Therefore, when the need for 4WD arises while driving in 2WD mode, when the switching lever 45 in the OFF position is manually operated to the ON side beyond the intermediate position M, the toggle spring is energized to the ON side. 49, a sufficient load is generated in the sleeve 43 to press the ball 51 and turn the ball clutch mechanism 50 into the engaged state, so there is a synchronous wait for the ball 51 to enter the ball hole 51a, that is, a dead zone state is realized. When the ball 51 enters the ball hole 51a, the switching lever 45 and sleeve 43 are automatically moved to turn the ball clutch mechanism 50 into the engaged state, thereby switching to the 4WD state.

[Effect of idea]

As explained above, in the present invention, a drive gear driven from a drive shaft of a running system that drives the rear wheels is rotatably provided on the front wheel drive shaft, and a ball is provided between the drive gear and the front wheel drive shaft. Even if a clutch is installed, the sleeve that connects and disconnects the ball clutch is slidably connected to a switching lever energized by a toggle spring that switches the clutch between an engaged state and a disengaged state. And, on the clutch entry side of the sleeve, the biasing force of the spring always acts to press the ball toward the front wheel drive shaft when the switching lever is operated beyond the intermediate position between the ON and OFF positions to the clutch entry side. Combined with the provision of the action slope, even when driving in 2WD, the ball clutch can be inserted into the sleeve by the toggle spring that biases the switching lever to the engaged state. Since a sufficient load has been generated to bring the ball clutch into the engaged state, a synchronized wait state is realized until the ball clutch is in the engaged state, and once synchronized, the switching lever and sleeve automatically move to bring the ball clutch into the engaged state. It can be switched to 4WD mode.

Therefore, although it has a simple structure in which a ball clutch is provided between the drive gear driven from the drive shaft of the traveling system and the front wheel drive shaft, it is possible to switch to 4WD mode without operating the main clutch during 2WD driving. Can be switched.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being an enlarged side view of the main parts, FIG. 2 being an enlarged side view showing the switching lever, and FIG. 3 being a sectional view taken along the line A-A in FIG. Fourth
The figure is a vertical side view of the transmission case showing the power transmission mechanism of an agricultural tractor, Figure 5 is a side view of the starting safety device installed on the clutch petal, and Figure 6 is the side view of the transmission case that shows the power transmission mechanism of the agricultural tractor.
FIG. 7 is an enlarged side view of the main part of the figure, and FIG. 7 is an overall side view of the agricultural tractor. 6...Rear wheel, 4...Transmission case, 26...Hydraulic drive continuously variable transmission mechanism, 30...Drive shaft of traveling system, 37...Front wheel drive shaft, 39...Drive gear, 43...Sleeve , 44... fulcrum shaft, 4
4a...Fork, 45...Switching lever, 49...
...Toggle spring, 50...Ball clutch mechanism, 51...Ball, 51a...Ball hole, 51
b...Ball guide hole, 52...Large diameter portion, 53...
Action slope.

Claims (1)

[Scope of utility model registration request] A drive gear driven by a drive shaft of a running system that drives the rear wheels is rotatably provided on a front wheel drive shaft, and a ball clutch is interposed between the drive gear and the front wheel drive shaft, and a sleeve is provided to connect and connect the ball clutch. A switching lever is provided in a slidable manner, and a switching lever engaged with the sleeve via a fork is swingably supported on the fuselage, and one end of the toggle spring is attached to the switching lever side with the fulcrum of the switching lever in between. Attach the other end of the toggle spring to the fuselage side, and then set the switching lever to the OFF position at the fixing point of the toggle spring on the fuselage side.
When the switching lever is positioned on the extension line of the switching lever when facing the intermediate position M of the ON position, and the switching lever is operated beyond the intermediate position M to the clutch entry side, the sleeve is biased by the toggle spring,
A four-wheel drive switch for a mobile agricultural machine configured so that the balls of a ball clutch provided in the sleeve can move in a direction in which they are pressed toward the front wheel drive shaft on a working slope formed continuously on a large diameter portion where the balls do not work. Device.