JPH035710Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention consists of a shift arm attached to an operating shaft for changing the swash plate angle in an axial plunger type hydraulic continuously variable transmission, and a shift arm that can be moved to any operating position. The present invention relates to a traveling speed change operation structure for a work vehicle in which a fixable speed change operation tool is linked.

[Conventional technology]

Conventionally, as a traveling speed change operation structure with the above configuration,
For combine harvesters, for example, Utility Model Application No. 57-101627, and for tractors, for example, Utility Model Application No. 57-101627.
There is one disclosed in Japanese Patent No. 66922, but in all of them, the speed change operating tool (a lever for a combine harvester, a pedal for a tractor) and an operating shaft are merely linked by a link mechanism.

[Problem that the invention attempts to solve]

In the axial plunger type hydraulic continuously variable transmission H/S/T, the operating shaft rotates and vibrates due to the pulsation of the reaction force acting on the swash plate, and this is transmitted to the link mechanism and at each fulcrum. There were cases where noise was generated and the gear shift operation tool vibrated.

In addition, since the swash plate angle is uniquely determined when the gear shift operating tool is fixedly set at the desired position, when the running load increases, the engine speed immediately decreases and the drive of the work equipment becomes difficult. This resulted in a problem that the speed decreased.

The present invention has been made with the aim of eliminating the above-mentioned conventional drawbacks.

[Means for solving problems]

In the traveling speed change operating structure having the above configuration, the present invention comprises the boss of the speed change arm consisting of an inner boss externally fitted and fixed to the operating shaft, and an outer boss externally fitted to this, and an inner and outer boss. The feature is that the two are elastically connected by an annular rubber interposed between them.

[Effect]

According to the above configuration, even if rotational vibration occurs on the operating shaft of the transmission, it is elastically absorbed between the operating shaft and the shift arm, and vibrations and noise generation of the link mechanism and shift operating tool are suppressed. Ru.

In addition, when the traveling load increases due to entering locally soft ground or turning the aircraft, the reaction force that returns the operating shaft to the low speed side increases as a characteristic of the hydrostatic continuously variable transmission.
The operating shaft rotates to the lower speed side while elastically deforming the annular rubber with respect to the fixed gear shift arm that corresponds to the fixed setting of the gear shift operating tool, and the running load is reduced as the running gear decreases. Therefore, an unreasonable decrease in engine speed is prevented.

[Effect of idea]

Therefore, by simply modifying the boss of the transmission arm attached to the operating shaft of the transmission to a double boss with an annular rubber interposed, two different problems found in conventional structures can be solved at once. We were able to.

Moreover, since the elastic flexibility is built into the boss of the transmission arm itself, the transmission arm can be easily attached to the operating shaft in the same manner as before.

〔Example〕

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

FIG. 6 shows a combine harvester as an example of a working machine, in which a threshing device 3 is mounted on a machine stand 2 equipped with a crawler traveling device 1, and a reaping pre-processing section 4 is connected to the front part of the machine stand 2. ing.

FIG. 3 shows the drive system of the crawler traveling device 1, in which the output of the engine 5 mounted on the machine base 2 is input to an axial plunger type hydraulic continuously variable transmission 7 via a transmission belt 6. The output is taken out to an axle 9 via a gear transmission case 8.

On the rear surface of the transmission 7 is an operating shaft (referred to as a trunnion shaft) 10 for changing and adjusting the angle of the internal swash plate to change the output rotation speed and rotation direction.
is provided in a protruding manner, and a speed change arm 11 is attached to the shaft end thereof.

On the side of the driver's seat 12 provided above the engine, a lever 13 as a gear change operation tool that can swing back and forth is provided, and an arm 1 is provided at the base of this lever 13.
4 and the transmission arm 11 are linked via a rod 15.

As shown in FIGS. 1 and 2, the boss of the speed change arm 11 is an outer boss 16 having an inner boss 16a and an arm 11, which are keyed to the operating shaft 10.
b, and an annular rubber 17 is baked between both bosses 16a and 16b, so that both bosses 16
a and 16b are constructed so that they can elastically rotate relative to each other within an appropriate range.

Further, the shift operating lever 13 can be fixedly set at any operating position by the following structure.

That is, as shown in FIGS. 4 and 5, a stepped support shaft 20 is attached to a boss 19 provided on the fixed frame 18.
is loosely supported, and on the protruding small diameter part of this support shaft 20,
The fixed plate 21, the friction plate 22, the gear shift operating lever arm 14, the flat washer 23, the pair of disc springs 24, 24, and the thrust bearing 25 are sequentially inserted and set by tightening with the double nuts 26, and then the gear shift operating lever arm is assembled. 14 is frictionally held at any rotational phase. Further, the fixing plate 21 is engaged with a pin 27 provided on the fixing frame 18 via a recess 28 and is prevented from rotating.
Rotation relative to the fixed frame 18 is allowed for a short period of time in the rotation direction between 7 and the recess 28,
A "play" for the speed change operation lever 13 is formed. This "play" has the function of ensuring that the operating shaft 10 returns to the neutral phase by an internal reaction force when the shift operating lever 13 is returned to the neutral position.

In addition, 29 in the figure is a reverse movement restraining pin that protrudes from the side surface near the base of the speed change operation lever 13 so as to be able to move up and down, and is engaged in a stepped elongated hole 31 of a restraining plate 30 attached to the fixed frame 18. Normally, operation is only allowed in the forward range F from the neutral position N, and transition to the reverse range R is permitted by pushing the knob 32 of the lever grip part 13a upward and pulling up the check pin 29. Further, 33 is a sliding contact type switch box that senses the operating position of the gear shift operating lever 13, which allows the engine to start only when the lever 13 is in the neutral position, and activates the back buzzer when the lever is in the reverse range R. Ru. Reference numeral 34 denotes an elastic expansion/contraction section interposed in the middle of the rod 15, which absorbs the stroke when the shift operation lever 13 is operated beyond the forward limit of the operation shaft 10.
The compression spring 35 is initially deformed stronger than the maximum reaction force of
It's decorated.

[Brief explanation of drawings]

The drawings show an embodiment of the traveling speed change operation structure for a working vehicle according to the present invention, FIG. 1 is a front view showing the operating section of the hydraulic continuously variable transmission, FIG. 2 is a cross-sectional plan view thereof,
Figure 3 is a schematic side view showing the drive system of the traveling device, Figure 4 is a front view of the gear shift operation lever attachment part, Figure 5 is a side view of the gear change operation lever attachment part as seen from the driver's side, and Figure 6. is an overall side view of the combine harvester. 7...Hydraulic continuously variable transmission, 10...Operation shaft, 11
...speed change arm, 13...speed change operating tool, 16a...inner boss, 16b...outer boss, 17...rubber.

Claims (1)

[Scope of utility model registration request] Work in which the shift arm 11 attached to the operating shaft 10 for changing the swash plate angle in the axial plunger type hydraulic continuously variable transmission 7 and the shift operating tool 13 that can be fixed at any operating position are linked together. A driving speed change operation structure for a vehicle, wherein the speed change arm 1
The first boss is composed of an inner boss 16a externally fitted and fixed to the operating shaft 10, and an outer boss 16b externally fitted thereto, and an annular rubber 17 with the inner and outer bosses 16a, 16b interposed between the two. A traveling speed change operation structure for a work vehicle that is elastically connected.