JPH054422Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is based on a standard transmission state in which the average circumferential speed of a pair of left and right front wheels is the same or almost the same as the average circumferential speed of a pair of left and right rear wheels; A transmission is provided that can be switched to an increasing transmission state in which the average circumferential speed of the front wheels of the pair of wheels is made larger than the average circumferential speed of the pair of rear wheels, and when the steering angle of the front wheels is less than a set value. the transmission is in the standard transmission state, and
A machine in which a rotary steering handle and a swinging operation part of the transmission are linked so that the transmission automatically enters the speed-up transmission state when the steering angle of the front wheels exceeds the set value. The present invention relates to a driving operation structure for an agricultural tractor provided with a type interlocking mechanism.

[Conventional technology]

In the above agricultural tractor, when the front wheels are steered beyond a set angle, the transmission automatically switches from the standard transmission state to the increased speed transmission state by the action of the mechanical interlocking mechanism, and performs a small turn. It is configured so that it can be done.

Regarding this type of agricultural tractor,
As proposed in No. 93679, the transmission control section should be
Through a cam mechanism to set the set steering angle,
The gear mechanism for the Pittman arm, which is linked to the Pittman arm and converts the rotational force of the steering handle into the rocking force for wheel steering operation, is used as the mechanism that converts the rotational force of the steering handle into the rocking force for operating the transmission. was. That is, as shown in FIG. 10, a mechanism 57 for converting the turning force of the steering handle 5 into a rocking force is provided separately from the steering mechanism 9 provided with the pitman arm 11, and the mechanism 57 converts the rotational force of the steering handle 5 into rocking force. This is designed to be more economical and advantageous than linking the swing operation section 36.

[Problem that the invention attempts to solve]

With the above configuration, the cam mechanism for setting the set steering angle is exposed, so dust, etc. may adhere to and accumulate on the cam mechanism, causing malfunction.There was room for improvement in this respect. .

An object of the present invention is to prevent the above-mentioned malfunction from occurring in a cam mechanism for setting a set steering angle.

[Means for solving problems]

The characteristic configuration of the present invention is that, in the aforementioned mechanical interlocking mechanism in the operating structure for running an agricultural tractor, the swinging interlocking member on the transmission side is connected to the case of the interlocking gear mechanism between the steering handle and the Pittman arm. In addition to being swingably mounted on the
A cam mechanism is provided inside the case for interlocking the rotating gear on the Pittman arm side constituting the interlocking gear mechanism with the swing interlocking member and for displaying the set value. Located in
Its action and effects are as follows.

[Effect]

The rotational force of the steering wheel is transmitted to the rotary gear by an interlocking gear mechanism, converting it into an operating force within one rotation, which is then branched and transmitted to the pitman arm side and the transmission side. Because of the cam mechanism, this is only transmitted when the front wheel steering angle exceeds a set value.

The case of the interlocking gear mechanism covers the cam mechanism to prevent dust from adhering thereto.

[Effect of idea]

By incorporating the cam mechanism that operates the transmission when the steering handle is operated beyond a certain level into the case of the interlocking gear mechanism between the steering handle and the pittman arm, the case of the interlocking gear mechanism can be used as a protective case for the cam mechanism. ,
Dust and moisture are less likely to adhere to the cam mechanism, making it highly reliable and less likely to malfunction.

〔Example〕

As shown in FIG. 9, a pair of left and right front wheels 1a,
1b that can be steered and driven, and a pair of left and right non-steering type rear wheels 2a, 2b that can be driven, and various working devices such as a rotary tiller can be operated up and down. The agricultural tractor is equipped with a lift arm 3 that can be freely connected and a power take-off shaft 4 that transmits power to a connecting work device.

To enable steering operation of the front wheels 1a and 1b,
As shown in FIGS. 1 and 2, an interlocking gear mechanism 9 is interlocked with the steering handle 5 via a rotating shaft 6, a gear transmission mechanism 7, and a rotating shaft 8.
A pitman arm 11 attached to the interlocking gear mechanism 9 so as to swing around an axis _P1 is interlocked with the knuckle arms 13 of each of the pair of front wheels 1a and 1b via a tie rod 12 to rotate the steering handle 5. By operating the pair of front wheels 1a, 1b, the operating force is transmitted and the pair of front wheels 1a, 1b are rotated about their respective axes _P2 .
a, 1b and a steering handle 5 are linked.

A transmission 15 for the front wheels 1a, 1b is installed inside the front end of the transmission case 14 forming the rear part of the traveling body.
is constructed as shown in FIGS. 3 and 6.

That is, a standard speed transmission gear 18 is interlocked with a front wheel output gear 16 of a driving transmission (not shown) via a gear 17 and is provided with a clutch pawl portion 18a;
and a speed increasing transmission gear 22 which is interlocked via a gear 20 and is equipped with a multi-plate friction clutch 21.
are attached to the output shaft 23 so as to be relatively rotatable, and a transmission member 25 which also serves as a transmission is attached to the output shaft 23 via a sleeve 24 so as to be integrally rotatable and slidable therein. A shifter 26 for slidingly operating the transmission member 25 is slidably attached to the transmission case 14 via a support shaft 27, and when the shifter 26 is operated to the first operation position S, the transmission member 25 is slidably attached to the transmission case 14. The standard speed transmission gear 18 is connected to the clutch pawl portion 25a which can be engaged with and disengaged from the clutch pawl portion 18a.
A pair of front wheels 1a, 1
The standard transmission state is established in which power is transmitted to the front wheel differential mechanism 28 so that the average circumferential speed of wheel b and the average circumferential speed of the pair of rear wheels 2a, 2b are the same or almost the same, and the shifter 26 is operated in the second operation. When operated to position N, the transmission member 25 disengages from the standard speed transmission gear 18 and becomes inactive with respect to the friction clutch 21, driving only the pair of rear wheels 2a, 2b and driving the pair of front wheels 1a, 1b. When the shifter 26 is operated to the third operating position H in a two-wheel drive state in which power transmission to the front wheels 1a and 1b is cut off so that the front wheels 1a and 1b are in an idle state, the transmission member 25 moves to the operating section 2.
5b, the friction clutch 21 is engaged and rotated integrally with the speed increasing transmission gear 22, and the average circumferential speed of the pair of front wheels 1a, 1b is changed to the average circumferential speed of the pair of rear wheels 2.
The speed increasing transmission state is such that the transmission is made to the front wheel differential mechanism 28 so that the speed is higher than the average circumferential speed of the wheels a and 2b. That is, by sliding the shifter 26 and sliding the transmission member 25, the two-wheel drive state can be switched between the three states described above.

A swinging arm 29 whose free end is engaged with the shifter 26 , an interlocking tool 31 which is interlocked with the shifter 26 via a rotary cylinder shaft 30 penetrating through the mission case 14 , and an interlocking tool 31 which is screwed into the mission case 14 . The shifter 26 is biased to the first operation position S by a spring 33 as shown in FIG. Further, an operating arm 36 as a swinging operating section for the transmission 15, which is interlocked with the rotating cylinder shaft 30 via the interlocking tool 31 and the rotating shaft 34, is attached to the transmission case 1.
The operating arm 36 is provided on the lateral outer side of the bottom of the 4WD so as to swing around the axis of the rotating shaft 34, and the operating arm 36 is operated to swing only when the operating lever 51, which will be described later, is operated to the first operating position 4WD _1. As the speed changes, the speed change member 25 is oscillated via the shifter 26 to change the speed.

As shown in FIGS. 1, 2, and 7, a case 10 of the interlocking gear mechanism 9 between the steering handle 5 and the pitman arm 11
a swinging interlocking member 37 on the transmission side that is slidably attached to the casing 10; and a rotating gear 38 on the Pittman arm side that constitutes the interlocking gear mechanism 9 inside the case 10.
and a cam mechanism 39 for interlocking with the swing interlocking member 37 and for displaying a set value, which will be described later.
A mechanical interlocking mechanism 41 in which the steering handle 5 and the operating arm 36 of the transmission 15 are interlocked by a pair of release wires 40, 40 interlockingly connecting the swing interlocking member 37 and the operating arm 36. has been configured.

As shown in FIG. 1, the cam mechanism 39 includes a cam groove 42 formed in the rotary gear 38 and a cam roller 45 fitted into the cam groove 42. Then, the plate member 44 provided with the cam roller 45 is integrally swung to the swiveling interlocking member 37, which is fitted onto the operating shaft 43 of the Pitman arm 11 so as to be relatively rotatable. They are linked together so that they can move freely. As shown by the solid line in FIG. 1, the front wheels 1a,
Pitman arm 1 is set in the set swing range L with neutral position A where 1b is in a straight-ahead state as an intermediate position.
1, the cam roller 45 is in a non-operating state, and the swing interlocking member 37 is maintained at the first position R by the action of the spring 33, and as shown by the imaginary line in FIG. When the pitman arm 11 is swung to the left side or the right side of the machine beyond the swing range L, the end 42 of the cam groove 42
a or 42b contacts and presses the cam roller 45, and the swing interlocking member 37 swings from the first position to the second swing position _F1 or _F2 , switching the shifter 26 to the third operating position H. It is designed to be operated. That is, when the steering angle of the front wheels 1a, 1b is less than the set value, the transmission 15 is in the standard transmission state, and when the front wheels 1a, 1b are steered beyond the set value, the transmission 15 is in the standard transmission state. The pitman arm 11 and the shifter 26 are interlocked so that the shifter 15 is automatically switched to the speed-up transmission state.

The interlocking tool 31 is slidably engaged with the rotary cylinder shaft 30 for spline engagement, and along with this sliding, the interlocking tool 31 is engaged with the engaging portion 34a so as to be integrally rotatable; It is configured to be detachable in a relatively rotatable manner. As shown in FIGS. 3 and 5, a support shaft 4 is attached to the mission case 14.
8 and the fixture 49, the interlocking tool operating member 50 is attached so as to swing around the first axis _X1 and the second axis _X2, respectively, and the operating lever 51 is attached to the fixture 49 together with the interlocking tool operating member 50. The cylindrical body 52 that is connected to the transmission case 14 so as to swing around the first axis X ₁ is slidably inserted thereinto, and the operating arm portion of the interlock tool operating member 50 50a, an operating mechanism 53 is connected with a pin so as to be relatively swingable, and is used to switch the transmission 15 and the interlocking mechanism 41 by rotating and sliding the interlocking tool 31 by manual operation of the operating lever 51. It is configured. That is, as the operating lever 51 is raised and lowered along the vertical groove portion 55a of the guide groove 55 formed in the guide 54 for the operating lever 51 so as to act on the projection 51a of the operating lever 51, the interlocking tool is operated. The guide groove 55 is configured such that the member 50 swings around the second axis X ₂ and slides the interlocking tool 31 with respect to the rotating cylinder shaft 30.
As the operating lever 51 is operated along the horizontal groove portion 55b of the
The interlocking tool 31 is pivoted around _X1 to press and rotate, and the interlocking tool 31 is allowed to be rotated by the spring 33. More specifically, when the operating lever 51 is operated to the first operating position 4WD, the interlocking tool 3 engages with the rotating shaft 34 as shown in FIG. When the interlocking device operating member 50 is placed in a position that allows the switching operation of the shifter 26, the transmission 15 can be switched between the standard transmission state and the speed increasing state by the Pitman arm 11. Then, when the operating lever 51 is operated to the second operating position 4WD, the interlocking tool 31 is disengaged from the rotating shaft 34 and the interlocking mechanism 41 is brought into a non-interlocking state, and the shifter 26 is moved by the spring 33 to the first operating position. When the operating position S is reached, the transmission 15 is maintained in the standard transmission mechanism. Then, when the operating lever 51 is operated to the third operating position 4WD, the interlocking tool 31 is disengaged from the rotating shaft 34, the interlocking mechanism 41 is brought into a non-interlocking state, and the shifter 26
The interlocking tool operating member 50 is in a position where the interlocking tool 31 is pressed against the spring 33 so that the lever is in the second operating position N, and the operating lever 51 is releasably held in the third operating position 2WD. Due to the action of the spring plate 56, the interlocking tool operation member 50 is in a locked state in which it receives and supports the interlocking tool 31 so as to maintain the shifter 26 at the second operating position N.
The transmission 15 is maintained in the two-wheel drive state.

In short, the operating lever 51 is moved to the first operating position 4.
When the WD is operated, the average circumferential speed of the front wheels 1a, 1b and the average circumferential speed of the rear wheels 2a, 2b are the same or almost the same, and the average circumferential speed of the front wheels 1a, 1b is the same as that of the rear wheels 2a, 2b. When the speed is higher than the average speed, both the front and rear wheels are driven while automatically changing gears in conjunction with the steering operation of the aircraft, and the operating lever 51 is moved to the second operating position 4WD.
When operated, both the front and rear wheels are driven while maintaining the average circumferential speed of the front wheels 1a, 1b and the average circumferential speed of the rear wheels 2a, 2b to be the same or almost the same regardless of the steering operation of the aircraft. When the operating lever 51 is moved to the third operating position 2WD, only the rear wheels 2a and 2b are driven.

As shown in FIG. 8 A and B, the operating lever 5
1 is formed to have a half-moon cross-sectional shape, and the holding force for holding the operating lever 51 at the third operating position 2WD is greater than that at the other operating positions 4WD or 4.
The leaf spring 56 is provided with a folded part 56a that is folded inward so as to be larger than the WD, and the lever 51 is moved to the third operating position by the cooperation of the flat part 51b of the lever 51 and the folded part of the leaf spring 56. It is firmly held so as to prevent it from moving unexpectedly due to the biasing force of the spring 33 from the 2WD.

[Brief explanation of the drawing]

The drawings show an embodiment of the driving operation structure for an agricultural tractor according to the present invention, in which Fig. 1 is a cross-sectional plan view of the cam mechanism, Fig. 2 is a side view of the mechanical interlocking mechanism, and Fig. 3 is an illustration of a transmission device. 4 is a cross-sectional view taken along the line - in FIG. 3, FIG. 5 is a cross-sectional view taken along the line - in FIG. 3, FIG. 6 is a cross-sectional view taken along the line - in FIG. 3, FIG. 7 is a sectional view of the swinging interlocking member, FIGS. 8A and 8B are views showing the shapes of the operating lever and the spring plate, and FIG. 9 is a side view of the tractor. FIG. 10 is a side view showing a comparative example of a mechanical interlocking mechanism. 1a, 1b...Front wheel, 2a, 2b...Rear wheel, 5...Steering handle, 9...Interlocking gear mechanism, 10...Case, 11...Pittmann arm, 15...Transmission device, 36...Sliding type operation unit, 37...swing interlocking member, 38... rotating gear,
39...Cam mechanism, 41...Mechanical interlocking mechanism.

Claims (1)

[Scope of utility model registration request] A standard transmission state in which the average circumferential speed of the pair of left and right front wheels 1a, 1b is the same or almost the same as the average circumferential speed of the pair of left and right rear wheels 2a, 2b, and the average circumferential speed of the pair of front wheels 1a, 1b is A transmission device 15 is provided which can be switched to a speed-up transmission state in which the speed is higher than the average circumferential speed of the pair of rear wheels 2a, 2b, and when the steering angle of the front wheels 1a, 1b is less than a set value, the speed is changed. A rotary steering handle is provided so that when the transmission device 15 is in the standard transmission state and the steering angle of the front wheels 1a, 1b exceeds the set value, the transmission device 15 automatically enters the increased speed transmission state. 5 and a swing type operating section 36 of the transmission 15, the mechanical interlocking mechanism 41 is configured by a transmission The side rocking interlocking member 37 is connected to the case 1 of the interlocking gear mechanism 9 between the steering handle 5 and the Pitman arm 11.
The rotary gear 3 on the Pitman arm side that constitutes the interlocking gear mechanism 9 is swingably attached to the gear mechanism 9.
8 and the swing interlocking member 37, and a cam mechanism 39 for displaying the set value is located inside the case 10.