JPH045564B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a transmission system for steerable front wheels with a standard drive state in which power is transmitted at a drive factor approximately equal to the rear wheel drive speed, and a rear wheel drive The present invention relates to a front wheel gear shift operation structure for an agricultural tractor equipped with a clutch type front wheel gear shifter that switches to an increased drive state in which transmission is performed at a drive speed greater than the vehicle speed.

[Conventional technology]

In a four-wheel-drive agricultural tractor equipped with a front-wheel transmission as described above, the first clutch of the standard drive system and the second clutch of the speed-up drive system of the front-wheel transmission are operated by forward and reverse operation of a shift member. In addition, the front wheel transmission is configured to be operated selectively when turning, and the front wheel transmission is automatically shifted to the speed increasing drive side when turning. Some devices are configured to be operated by

In this way, by increasing the speed of the front wheels when turning, it is possible to make sharp turns without disturbing the ground. The configuration is also such that the connection between the human operating tool and the shift member is cut off, so that the front wheels can be kept in the standard drive state both when traveling straight and when turning.

[Problem that the invention seeks to solve]

As described above, when the front wheel transmission is configured to selectively engage the first and second clutches by forward and reverse operation of the shift member, the shift member can be moved between the first clutch engaged position and the second clutch engaged position. If the front wheel transmission device is operated and held at a neutral position, power transmission is cut off in this front wheel transmission, and no power is transmitted to the front wheels. In other words, it is possible to bring out the rear two-wheel drive state.

Then, when a configuration that makes the rear two-wheel drive state appear is added, the following problem occurs. In other words, there is an operating member that switches the manual operating tool and the shift member of the front wheel transmission into a linked/unlinked state (see the item [Prior Art] above), and an operating member that moves the shift member of the front wheel transmission to the neutral position. Because two sets of operating members (for displaying the rear two-wheel state) are required,
There is room for improvement in terms of structural simplification.

An object of the present invention is to simplify the operation system of a front wheel transmission of an agricultural tractor.

[Means for solving problems]

The feature of the present invention is that the front wheel speed change operation structure for an agricultural tractor as described above is configured as follows. In other words, the first clutch of the standard drive system and the second clutch of the speed increasing drive system of the front wheel transmission are
The shift member is configured to be selectively engaged by forward/reverse operation of the shift member, and is provided with a switching mechanism for switching the manual operating tool and the shift member of the front wheel transmission between a linked state and a non-linked state. An operating member for switching the switching mechanism is interlocked and connected to the front wheel transmission side of the switching mechanism, and when the human operating tool is operated in a direction different from the link switching direction at the non-linked operating position, the switching mechanism is operated via the operating member. The shift member is configured to be operable, and its functions and effects are as follows.

[Effect]

With the configuration as described above, the manual operating tool and the shift member of the front wheel transmission can be switched between linked and unlinked states using the operating member. When the operating member operates the manual operating tool and the shift member in a non-coupled state, the operating member allows the shifting member to be operated to the neutral position independently of the manual operating tool.

〔Effect of the invention〕

Therefore, it has become possible to switch between linkage and non-linkage between the manual operating tool and the shift member and to operate the shift member to the neutral position using one set of operating members.
As a result, the number of operating members that conventionally required two sets is reduced to one.
It was possible to simplify the structure by combining them into a set.

[Example] Hereinafter, an agricultural tractor that is an example of the present invention will be described based on the drawings.

As shown in FIG. 6, a fuselage frame 3 that supports a pair of left and right steering type front wheels 1, 1 and rear wheels 2, 2 in a freely drivable manner includes an engine 4, a main clutch 5, a transmission case 6, and a control section. 7, a lift arm 8 that can be driven up and down to freely swing up and down to connect various work devices such as a rotary tiller to the rear of the machine, and a PTO that transmits power to the work devices.
A four-wheel drive agricultural tractor is constructed by providing a shaft 9.

Next, to explain in detail the power transmission system and front wheel transmission 10 of the agricultural tractor, as shown in FIGS. 3 and 6, power from the engine 4 is transmitted to the transmission case via the main clutch 5 and the power transmission shaft 11. The transmission is transmitted to the main transmission device and the sub transmission device (not shown above) in the output shaft 12 for gear shifting operation, and is transmitted from the output shaft 12 to the rear wheel fat mechanism 2a.
The power branched from the second gear 12a is sent to the front wheel transmission 10 via the gear 13, and the speed is changed.
It is configured to be sent from the front wheel output shaft 15 to the front wheel differential mechanism 1a.

Next, the front wheel transmission 10 will be described in detail. As shown in FIG. They are interlocking. Then, both the first passive gear 16 that meshes with the gear 14a and the second passive gear 17 that meshes with the gear 14c fixed to the other end of the transmission shaft 14 are loosely fitted onto the front wheel output shaft 15. 1st and 2nd
A shift member 18 is mounted between the passive gears 16 and 17 with a spline structure so as to rotate integrally with the front wheel output shaft 15 and to be slidable in the axial direction.

This shift member 18 has claw-shaped engaging portions 18a and 18b at the front and rear in the shift direction.
a, 18b are engaged with and disengaged from the engagement portions 16a, 17a of the first and second driven gears 16, 17, thereby creating an engagement type first clutch 19 between the shift member 18 and the first driven gear 16. A second clutch 20 of an engaging type is constructed between the shift member 18 and the second passive gear 17. And the first
The clutch 19 is provided with a rubber ring 21 that absorbs shock during occlusion.

With the above structure, when the shift member 18 is engaged with the first passive gear 16, the power from the output shaft 12 is transmitted to the front wheels 1, 1 and the rear wheels via the gears 13, 14a, the first passive gear 16, and the shift member 18. 2 and 2 are driven at approximately the same speed in the standard drive state, the front wheel output shaft 1
5. Then, the shift member 18 is moved to the second position.
When engaged with the passive gear 17, the power is transferred to the gears 13 and 1.
4b, transmission shaft 14, gear 14c, second passive gear 1
7. The front wheels 1, 1 are transmitted to the front wheel output shaft 15 via the shift member 18 in an accelerated driving state in which the front wheels 1, 1 are driven at a higher speed than the rear wheels 2, 2.

Next, the operating system of the shift member 18 will be described in detail. As shown in FIG. 1, the front wheel output shaft 1
The shifter 22 of the shift member 18 is attached to the support shaft 28 so as to be movable in parallel with the front wheel output shaft 15, and the operating section 23 for sliding the shifter 22 in the axial direction is moved below the front wheel output shaft 15 in a direction perpendicular to the front wheel output shaft 15. The operating portion 23 is freely fitted onto the supported operating shaft 24 and attached to the standard drive side (the first clutch 19 entry side where the shift member 18 engages with the first passive gear 16) by the helical spring 25. It is strong.

Next, the switching mechanism 29 for linking the operating section 23 and the operating shaft 24 operated from outside the device will be described in detail.As shown in FIG.
A spline portion 23a is provided at the end of the boss portion of the shift member 26, which is fitted onto the spline portion 23a.
The spline part 2 fixed to the end of the operating shaft 24
4a so that the operating portion 23 and the operating shaft 24 rotate together. And the human operating tool 27
By rotating the operating shaft 24 around the axis by stepping on the handbrake pedal, which is an example, the shift member 18 is moved to the speed-increasing drive side (the shift member 18 engages with the second passive gear 17). 2 clutch to the 20 entry side). In addition, operation axis 2
As shown in FIG. 5, the spline portion 24a of No. 4 is
The tip of each tooth of the shift member 26 is formed into a tapered shape.
This ensures that the occlusal operation is performed smoothly.

Next, the interlocking mechanism between the side brake pedals 27, 27 and the operating shaft 24 will be described in detail. As shown in FIG.
Lever arms 27a, 2 are attached to each of the support boss portions 7
7a is erected, and both lever arms 27a, 27
a U-shaped member 34 that has elongated holes 37, 37 as shown in the figure, inserts a pin 33 through both elongated holes 37, 37, and supports both ends of this pin 33; The operating lever 24b at the end of the operating shaft 24 shown in FIGS. 1 and 2 is interlocked and connected via a release wire 35 and a return spring 36. Further, the operating shaft 24 is biased toward the standard drive side by a helical spring 38, and is prevented from rotating further from the standard drive side by a stopper 39 and a roll pin 40.

Next, the operation system of the switching mechanism 29 will be described in detail. As shown in FIGS. 1 and 4, a boss is rotatably supported around a horizontal axis _P1 in the left-right direction of the transmission case 6. An L-shaped operating member 31 is supported in the section 30 so as to be rotatable around a horizontal axis _P2 in the longitudinal direction of the fuselage, and one end of this operating member 31 is provided above the shift member 26 of the switching mechanism 29. It is stuck in the recessed part. When the operating member 31 is rotated around the horizontal axis _P2 , the shift member 26 in the switching mechanism 29 engages with the spline portion 24a of the operating shaft 24, and the handbrake pedal 2
7 and 27 and the shift member 18 of the front wheel transmission 10 are in a linked state, and the front wheel transmission 10 is automatically operated to the speed increasing drive side by depressing the handbrake pedal 27 on one side.

Next, when the shift member 26 is released from the spline portion 24a, the above-mentioned state of linkage between the handbrake pedals 27, 27 and the shift member 18 is released (the state shown in FIG. 1). and operation member 3
1 around the horizontal axis P ₁ and held, the shift member 18 of the front wheel transmission 10 is moved to the standard drive side via the operation section 23 and the shifter 22.
It can be operated to the speed-up drive side and to the rear two-wheel drive position from the neutral position. Incidentally, as shown in FIG. 4, the shift member 26 is equipped with a ball detent mechanism 32, and is configured to reliably hold the shift member 26 in the linked and unlinked states. .

[Brief explanation of drawings]

The drawings show an embodiment of the front wheel speed change operation structure for an agricultural tractor according to the present invention, FIG. 1 is a front view of the front wheel speed change device and the operation system, and FIG. 2 is a diagram showing the interlocking state of the front wheel speed change device and the front wheel speed change device. , FIG. 3 is a side view of the front wheel transmission, FIG. 4 is a longitudinal cross-sectional side view of the operating member and the shift member in the switching mechanism, FIG. 5 is a partially enlarged side view of the spline part in the switching mechanism, and FIG. 6 is a side view of the front wheel transmission.
The figure is an overall side view of an agricultural tractor. 1...Front wheel, 10...Front wheel transmission, 18...
Shift member, 19...first clutch, 20...second clutch, 27...human operating tool, 29...switching mechanism, 31... operating member.

Claims (1)

[Claims] 1 Switch the transmission system to the steerable front wheels 1, 1 between a standard drive state in which transmission is performed at a drive speed approximately equal to the rear wheel drive speed, and an increased speed drive state in which power is transmitted at a drive speed greater than the rear wheel drive speed. This is a front wheel shift operation structure for an agricultural tractor equipped with a clutch-type front wheel transmission 10, in which a first clutch 19 of a standard drive system and a second clutch 20 of an increased speed drive system of the front wheel transmission 10 are connected to a shift member 18. The manual operation tool 27 and the shift member 18 of the front wheel transmission 10 are configured to be selectively engaged by forward and reverse operation of the
A switching mechanism 29 is provided for switching between a linked state and a non-linked state, and an operating member 31 for switching the switching mechanism 29 is interlocked and connected to the front wheel transmission 10 side of the switching mechanism 29.
7. A front wheel speed change operation structure for an agricultural tractor, wherein the shift member 18 can be operated via the operating member 31 by operation in a direction different from the link switching direction at the non-link operating position.