JPH02159442A - Gearshift construction of work vehicle - Google Patents

Abstract

PURPOSE:To reduce the number of gears and simplify construction to reduce cost by spline-fitting a slide-free No.2 driven gear on an output ahaft at a first gearshift position, second gearshift position and neutral position and fitting a normal and reverse switch-over gear on a supporting shaft. CONSTITUTION:A No.2 driven gear 18 is free to slide to a first gearshift position where meshed with a No.1 driven gear 17, to a second gearshift position where meshed with a No.2 drive gear 8, and to the neutral position. Either of a third gearshift condition, neutral condition, and fourth gearshift condition is produced by sliding a No.3 driven gear 19 and a No.4 driven gear 20 by shifting a counter shiftgear 21. A normal and reverse switch-over gear 23 fitted on a supporting shaft 22 is free to slide to either a reverse drive condition where meshed with the No.2 driven gear 18 and the No.2 drive gear 8 or a idle condition where meshed with the No.2 drive gear 18 only. Thus, four-stage gearshifting in normal direction and switching-over between normal and reverse rotation can be made.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gear transmission structure for a working vehicle such as an agricultural tractor, and more specifically, the present invention relates to a gear transmission structure for a working vehicle such as an agricultural tractor. The present invention relates to a gear transmission structure for a work vehicle that has multiple gears arranged in a reverse direction and performs switching gears in a reverse direction.

[Prior Art] As the above-mentioned conventional structure, for example, there is a structure shown in FIG. 2, which performs four-stage switching in the forward rotation direction and one-stage switching in the reverse rotation direction. In other words, four forward rotation switching drive gears (31) rotate integrally with the input shaft (1).
), (32), (33).

Four driven gears (35) that are constantly engaged with (34), respectively.
.

(36), (37), (38) as output shaft (2)
and a shift gear (39) for switching between 1st and 2nd speeds and a shift gear (39) for switching between 3rd and 4th speeds.
40) to rotate together, and both shift gears (39)
, (40) is configured to perform switching between four stages of normal rotation by the switching selection shift operation. And the third axis (41)
Two intermediate gears (42) and (43) fitted loosely on the
One of the gears (42) is always interlocked with the first drive gear (31), and the other gear (43) is connected to the output shaft (2) between the second drive gear (36) and the third driven gear (37). ), and the rain intermediate gears (42) and (43) are rotated in conjunction with each other by the shift operation of the forward/reverse switching shift gear (45). The state where the output shaft (2) is reversed and the intermediate gear (43)
) and the reverse gear (44) are configured to switch to an idle state in which they do not contribute to transmission.

[Problem to be solved by the invention]

In the above conventional structure, the forward rotation transmission system and the reverse rotation transmission system transmit power through separate transmission gears, which increases the number of gears, complicates the structure, and increases cost. There was a problem.

The present invention aims to simplify the structure and reduce costs through rational improvements.

(Means for Solving the Problems) A feature of the present invention is that in the gear transmission structure for a work vehicle having the above configuration, a first driven gear that is always engaged with a first drive gear fixed to the input shaft is connected to the output shaft. A first gear shifting position is fitted loosely and externally into the spline shaft integrally formed with the first driven gear, and a second shifting position is engaged with a second drive gear fixed to the human-powered shaft.
A second driven gear that can be slid freely between a speed change position and a neutral position in which no mesh is engaged is fitted onto the output shaft with a spline, and the second driven gear and the second driving gear are respectively in the neutral position. A forward/reverse switching gear that can freely slide between an engaged state and an idle state that does not contribute to power transmission is fitted externally to a support shaft parallel to both of the axes,
Its actions and effects are as follows.

[For production]

That is, when the second driven gear is shifted to the first shift position, the power of the input shaft is transmitted to the output shaft via the first drive gear, the first driven gear, and the second driven gear, and the first normal rotation shift is performed. When the second driven gear is shifted to the second shift position, power is transmitted through the second drive gear and the second driven gear, and the normal rotation second shift state is set. During reverse rotation, the reverse rotation power is transmitted to the output shaft via the second drive gear, forward/reverse switching gear, and second driven gear.

(Effects of the Invention) Therefore, according to the present invention, the second driven gear can be commonly used as a transmission gear in both the two-stage switching state of forward rotation switching and the reverse rotation state, and the A single reverse switching gear is required.As a result, the number of gears can be reduced, simplifying the structure and reducing costs.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a gear change structure of an agricultural tractor, which is an example of a working vehicle according to the present invention. In this gear transmission structure, from an input shaft (1) to which the power of an engine (not shown) is transmitted, to a power take-off shaft (2), which is an example of an output shaft, and a power transmission shaft (3) for driving the aircraft, the transmission shaft is connected in the normal rotation direction. It is constructed so that power can be transmitted in four stages and one stage in the reverse direction.

The traveling transmission system will be explained below. Power transmission from the engine! A gear (5) attached to the shaft end of 1II (4),
A gear (6) attached to the shaft end of an input shaft (1) parallel to the power transmission shaft (4) is interlocked to rotate the human power shaft (1) in a fixed direction. The input shaft (1) is provided with four drive gears (7), (8), (9), and (10) for integral rotation, and the first drive gear (7) with the smallest diameter
) is interlocked and interlocked with the first traveling transmission gear (11) which is loosely fitted onto the transmission shaft (3).

The second traveling transmission gear (12) externally fitted with a spline on the transmission shaft (3) has a first traveling transmission position where it meshes with a spline shaft portion (lla) formed on the negative side of the first transmission gear (11);
It is configured to be able to be freely shifted to a second travel gear position where it engages with the second drive gear (8).

And a third drive gear (9) and a fourth drive gear (10)
are respectively the third transmission gears (
13), is interlocked with the fourth transmission gear (14),
The intermediate shift gear (15) is moved to a third traveling shift position where it engages with the spline shaft portion (13a) of the third transmission gear (13) and a third travel shift position where it engages with the spline shaft portion (14a) of the fourth transmission gear (14). It is externally fitted onto the transmission shaft (3) so that it can be shifted freely between four travel gear positions and rotated integrally. On the other hand, a forward/reverse switching mechanism (16) is provided at the end of the transmission shaft (3).

Next, the drive transmission system of the power take-off shaft (2) will be explained.

A first driven gear (17) that constantly meshes with the first drive gear (7) is fitted onto the power take-off shaft (2), and a second driven gear (18) is fitted onto the outside with a spline. . This second driven gear (18) is the − of the first driven gear (17).
Slide switching operation between a first gear shift position where the spline shaft portion (17a) integrally formed on the side engages, a second shift position where the gear shift engages with the second drive gear (8), and a neutral position where the gear engages neither of the gears. It is configured freely. The third driven gear (19) and the fourth driven gear (20) are freely fitted onto the power take-off shaft (2), and the third driven gear (
9), the fourth drive gear (10) is interlocked with each other, and by switching the intermediate shift gear (21),
It is configured to selectively exhibit either the third shift state, the neutral state, or the fourth shift state.

And a support shaft (2) parallel to the above-mentioned both shafts (1) and (2).
2) is externally fitted with a forward/reverse switching gear (23), and this forward/reverse switching gear (23) is connected to each of the second driven gear (18) and the second drive gear (8) in the neutral position. The second driven gear (18) is configured to be able to freely switch between a reverse drive state in which the second driven gear (18) engages and an idle rotation state in which only the second driven gear (18) engages and does not contribute to transmission.

By shifting the second driven gear (18) or the shift gear (21), four-step switching in the forward direction can be performed, and by shifting the forward/reverse switching gear (23), forward/reverse switching can be performed. It is possible.

(Another example) ■ The number of switching gears in the forward rotation direction is not limited to 4 gears.
Any number of stages may be used as long as it is two or more stages.

■ The forward/reverse switching gear (23) is the second drive gear (8).
The second driven gear (18) may be configured to be freely switchable between a state in which it engages with each other and a state in which it does not engage with any of the gears (8) and (18).

The present invention is applicable not only to agricultural tractors but also to various work vehicles such as rice transplanters and lawn mowers.

Moreover, it may be used not only in a power extraction transmission structure but also in any transmission system such as a traveling transmission system.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a gear shifting structure for a working vehicle according to the present invention, and FIG. 2 is a sectional view showing a conventional example. (1)...Input shaft, (2)...Output shaft, (7)...First drive gear, (8)...
...Second driving gear, (17) First driven gear, (18)
...Second driven gear, (23)...Forward/reverse switching gear.

Claims (1)

[Claims] A gear transmission structure for a work vehicle that shifts power from an input shaft (1) to an output shaft (2) parallel to the output shaft (2) in a plurality of stages in the forward rotation direction and in the reverse rotation direction. 1)
A first driven gear (17) that constantly meshes with a first driving gear (7) fixed to the output shaft (2) is fitted loosely on the output shaft (2) and is integrally formed on one side of the first driven gear (17). a first gear shift position in which the input shaft engages with the spline shaft portion (17a), a second shift position in which the input shaft engages with the second drive gear (8) fixed to the input shaft (1), and a neutral position in which the input shaft engages with neither of the gears. A second driven gear (18) which can be slid freely is fitted onto the output shaft (2) by a spline, and when the second driven gear (18) is in a neutral position,
18) and the second drive gear (8), respectively, and a forward/reverse switching gear (23) which can be slid freely between a state in which it engages with each other and an idle state in which it does not contribute to power transmission, is attached to both the shafts (1) and (2). A gear transmission structure for a work vehicle that is externally fitted onto a support shaft (22) parallel to the .