JPH03220024A - Advance and retreat changeover transmission gear for tractor - Google Patents

Abstract

PURPOSE:To prevent sudden departure by providing inside the friction clutch mechanisms shock absorbing mechanisms which prevent sudden power transmission to a changeover clutch at the time of engagement between this friction clutch mechanism and the changeover clutch. CONSTITUTION:For the device in the caption, a gear 4 for advance, to which the power of a prime mover is inputted through an input shaft 18 and a gear 5, a gear 8 for retreat, to which the rotation of this gear 4 is inputted through the gears 5 and 6, are provided respectively freely in rotation on the transmission shaft 2 to be coupled with a transmission mechanism. Moreover, in opposition to each of shafts 4 and 8, friction clutch mechanisms 9 and 10 to which power is transmitted from each of gears 4 and 8 are provided, and also a changeover clutch 11, which couples either one of clutch mechanisms 9 and 10 with the transmission shaft 2 by sliding operation, is provided between both friction clutch mechanisms 9 and 10. In this case, shock absorbing mechanisms 12, which prevent the sudden power transmission to the changeover clutch 11 during the engagement of the changeover clutch 11, are provided inside the friction clutch mechanisms 9 and 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a forward/reverse switching transmission for a tractor.

(Prior art and problems to be solved by the invention) On the transmission shaft that transmits power to the speed change transmission mechanism, there is a forward friction clutch mechanism that transmits power from the prime mover side, and a mechanism for reverse rotation with respect to this forward friction clutch mechanism. A friction clutch mechanism for reverse movement is provided, which is transmitted through a gear train necessary for the two friction clutch mechanisms, and a transmission shaft between the two friction clutch mechanisms is provided with a mechanism that engages one of the friction clutch mechanisms by a sliding operation. In a tractor forward/reverse switching transmission device which is equipped with a switching clutch that transmits power from the friction clutch mechanism to the transmission shaft, especially when switching between the front/reverse switching transmission device, If the switching clutch is operated rapidly, unlike shifting only forward gears, for example, the gear will be rapidly switched from forward to reverse, and the vehicle will start suddenly, which may give a shock to the operator or be dangerous. .

(Means for Solving the Problems) The present invention provides a transmission shaft 2 that transmits power to a speed change transmission mechanism 1.
A forward gear 4, which is transmitted from the prime mover 3 side, and a reverse gear 8, which is transmitted from the forward gear 4 through each gear 5°6.7 necessary for reverse rotation, are rotatable at regular intervals. Friction clutch mechanisms 9 and 1o, which are respectively transmitted from the gears 4 and 8, are provided in opposition to these gears 4. In the forward/reverse switching transmission device provided with a switching clutch 11 that engages with either one of the friction clutch mechanisms 9 through a sliding operation and transmits transmission from the friction clutch mechanism 9 to the transmission shaft 2, both of the friction clutches are connected to each other. A tractor characterized in that mechanisms 9 and 10 are each provided with buffer mechanisms 12 and 12 for preventing sudden transmission of power to the changeover switch 11 when the friction clutch mechanism 9 and the changeover clutch 11 are engaged. The configuration is a front/reverse switching transmission device.

(Operation of the Invention) When the switching clutch 11 is operated to engage the forward friction clutch mechanism 9 side, the friction clutch mechanism 9 is buffered by the buffer mechanism 12, passes through a half-clutch state, and enters the engaged side.
The forward gear 4, which is transmitted from the side, is connected to a forward friction clutch mechanism 9. The transmission is transmitted to the variable speed transmission 1 via the switching clutch 11 and the transmission shaft 2.

Conversely, the switching clutch 11 is replaced by the reverse friction clutch mechanism 10.
When the friction clutch mechanism 10 is switched to the side, the friction clutch mechanism 10 is buffered by the buffer mechanism 12, goes through a half-clutch state, and enters the engaged side, and the forward gear 4, which is transmitted from the prime mover 3 side,
, 6, 7, the reverse gear is transmitted to the speed change transmission mechanism 1 via the reverse gear 8, the friction clutch mechanism 10, the switching clutch 11, and the transmission shaft 2.

(Effect of the invention) Due to this kind of action, as in the above-mentioned problem.

Since there is no sudden start when the switching clutch is operated to switch between forward and reverse switching between forward and reverse, there is no risk of shock or danger to the operator.

(Example) In the case of rotation, a bonnet 1 in which a prime mover 3 is mounted is placed on a frame 14 on which a pair of left and right front wheels 13 and 13 are mounted.
5 is provided on the rear side of the prime mover 3.

A main clutch 16 that connects and disconnects power transmission from the prime mover 3
A clutch case 17 is provided at the rear end of the frame 14 to transmit power from the main clutch 16 via an input shaft 18.

A front case 19 in which a reverse switching transmission device is installed is provided, and a pair of left and right rear wheels 20.
20 is mounted on the shaft, and a rear case 21 is connected to the rear case 21, which houses a variable speed transmission mechanism 1 for transmitting power to these rear wheels 20°2o. Note that 22 is a handle for steering the front axles 13, 13, and 23 is a fender 124 that covers the upper part of the rear wheels 20, 20, which is a driver's seat for the passenger.

The input shaft 18 is mounted on the front wall 19a of the front case 19.
A bearing 18a supporting the rear end is provided, and an input gear 25 integral with the input shaft 18 is provided at the rear end of the input shaft 18. The front and rear wheel bearings 26 and 26 provided on the lower side of the bearing 18a and the rear wall of the front case 19 each have a shaft coupling 2a at their rear end to transmit power to the speed change transmission mechanism 1. The transmission shaft 2 is supported.

A gear body consisting of a boss portion 4b having a spline 4a on the outer circumferential surface and a forward gear 4 meshing with the input gear 25 is rotatably provided on the front part of the transmission shaft 2. A gear body consisting of a boss portion 8b having a spline 8a on the outer circumferential surface and a reverse gear 8 at the rear end of the boss portion 8b is rotatably provided at the rear portion of the top portion 2.

A clutch case 27 of the friction clutch mechanism 9 having a clutch pawl 27a on the rear surface is provided on the rear side of the boss portion 4b and the front side of the boss portion 8b on the transmission shaft 2.

Friction clutch mechanism 1 having a clutch pawl 28a on the front part
0 clutch cases 28 are rotatably provided, and on the spline 2b provided on the transmission shaft 2, there are a clutch pawl 11a that is slidably engaged with the clutch pawl 27a and a clutch pawl that is slidably engaged with the clutch pawl 28a. 11a is provided so as to be slidable on a spline.

On each of the splines 4a, 8a, a pressure plate 29.29 having a boss portion 29a and a disc-shaped pressure plate 30.30 are provided so as to be able to freely slide along the spline.
Between 29 and 30, the clutch cases 27 and 2 are
A plurality of friction plates 31, 31 whose outer diameter portions are engaged with the slits provided in 8 and a plurality of friction plates 31a, 31a whose inner diameter portions are engaged with outer splines 4a, 8a are arranged alternately. do.

Furthermore, spherical recesses 32a, 32a of the buffer mechanism 12.12 into which substantially hemispherical portions of a plurality of spheres 32.32 are fitted are provided on the inner surfaces of the walls of the clutch cases 27, 28, respectively, and the pressure plates 30.30 The friction plates 31, 31a . . .
Recesses 30a, 30a for pressing the splines 4a, 8a are provided, and the friction plates 29, 29 are provided between the disc-shaped receiving members 33, 33 provided on the splines 4a, 8a and the pressure plates 29, 29. 31, 31a, . . . are each provided with springs 34, 34 that press them into a half-clutched state.

Both the front and rear bearings 35 and 35 provided below the two bearings 26 and 26 respectively support a transmission shaft 36 that transmits power to a power take-off shaft (not shown) at the rear end of the vehicle body. is provided with a gear 5 that meshes with the forward gear 4 and a gear 6 located below the reverse gear 8, and these gears 8.
, 6 is provided with a gear 7 which is pivotally supported by the rear wall of the north front case 19 and meshes with the gears 8 and 6.

Next, the effect will be explained. The main clutch 16, which is transmitted from the prime mover 3, connects friction plates 31a and 3 via an input shaft 18, an input gear 25, a forward gear 4, and a spline 4a.
1..., and these friction plates 31a, 31
From a, power is transmitted to the clutch case 27 via the friction plates 31, 31, . . . and slit portions.

When the switching clutch 11 is slid and the clutch pawl 11a is engaged with the clutch pawl 27a, the driving resistance caused by this engagement displaces the concave portion 30a of the pressure plate 30 that is attached to the spheres 32 and 32 in the rotational direction, so that one sphere is displaced. 32, 32, each friction plate 31, 3La, . The power is transmitted to the transmission shaft 2 via the pawl 11a, the switching clutch 11, and the spline 2b, and from the transmission shaft 2 to the rear wheels 20, 20 via the shaft coupling 2a and the speed change transmission mechanism 1 in forward rotation.

On the other hand, the gear 5 which is transmitted from the forward gear 4 is connected to the clutch case 28 via the transmission shaft 36, gears 6, 7, 8, spline 8a, and each friction plate 31a, 30...
It is transmitted to Clutch pawl 11a of switching clutch 11
When the friction clutch mechanism 10 is engaged with the clutch pawl 28a, the friction clutch mechanism 10 is brought into the input side by the same action as described above, and the clutch case 2
8 to clutch pawl 28a, 1. The switching clutch 11, which is transmitted through the transmission gear 1a, transmits rotation in the reverse direction to the rear wheels 20, 20 through the spline 2b, the transmission shaft 2, the shaft coupling 2a, and the speed change transmission mechanism 1.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, with FIG. 1 being a sectional side view and FIG. 2 being a side view of the entire device. In the figure, numeral 1 is a variable speed transmission mechanism, 2 is a transmission shaft, 3 is a prime mover,
4 is a forward gear, 5, 6.7 is a gear, 8 is a reverse gear,
9.10 is a friction clutch mechanism, 11 is a switching clutch, 1
2 indicates a buffer mechanism.

Claims (1)

[Claims] On the transmission shaft 2 that transmits the transmission to the variable speed transmission mechanism 1, there is a forward gear 4 that is transmitted from the prime mover 3 side, and a reverse gear that is transmitted from the forward gear 4 via the gears 5, 6, and 7 necessary for reverse rotation. gears 8 are provided rotatably at regular intervals, and friction clutch mechanisms 9 and 10 are provided facing each other, and each of these gears 4 and 8 is provided with friction clutch mechanisms 9 and 10, which are respectively transmitted from the two gears 4 and 8. A switching clutch 11 is provided on the transmission shaft 2 between the clutch mechanisms 9 and 10, which engages one of the friction clutch mechanisms 9 by a sliding operation and transmits transmission from the friction clutch mechanism 9 to the transmission shaft 2. In the forward/reverse switching transmission device, in both the friction clutch mechanisms 9 and 10, when the friction clutch mechanism 9 and the switching clutch 11 are engaged,
A forward/reverse switching transmission device for a tractor, characterized in that a buffer mechanism 12, 12 is provided to prevent sudden transmission to the changeover switch 11.