JPH0717286A - Speed change structure for walking working machine - Google Patents

Abstract

PURPOSE:To eliminate troublesome operation between main speed change and subsidiary speed change in a speed change structure for a walking working machine equipped with a main speed changer and a subsidiary speed changer. CONSTITUTION:A main speed change lever 7 and a subsidiary speed change shaft 6 are linked together via a link mechanism 8 which rotates the subsidiary speed change shaft 6 around its shaft center with the oscillation of the main speed change lever 7 around a lateral shaft center X1, and a cum mechanism is provided between the subsidiary speed change shaft 6 and a shift fork externally mounted on the subsidiary speed change shaft 6 to slide the shift fork with the rotation of the subsidiary speed change shaft 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a walk-type working machine such as a walk-type cultivator and a walk-type management machine provided with a main transmission and an auxiliary transmission, and more specifically, to a side surface of a mission case.
The present invention relates to a gear shift operation structure of a walk-behind work machine including a plurality of gear shift shafts for main gear shift and a sub gear shift shaft capable of shifting between high and low stages.

[0002]

2. Description of the Related Art Conventionally, when operating a main transmission shaft and a sub transmission shaft on the side of a transmission case, as shown in Japanese Patent Laid-Open No. 64-70231, an operation lever for a main transmission and an auxiliary transmission shaft are provided, respectively. It is designed to be operated separately by the operating lever for gear shifting.

[0003]

According to the above-mentioned conventional structure, when operating the main transmission and the sub-transmission, the shift lever must be changed every time, which makes the shift operation troublesome. It was

It is an object of the present invention to enable operation of a main transmission and an auxiliary transmission without changing gears.

[0005]

A characteristic structure of the present invention for achieving the above object is to provide a plurality of shift shafts for main shifting and a sub-shift shaft capable of shifting between high and low stages on a side surface of a mission case. In a walk-behind work machine provided with the plurality of shift shafts for the main shift, along with a swing operation around a horizontal axis, the selected shift shaft is accompanied by a swing operation around a vertical axis. A main gear shift lever for sliding operation and the sub gear shift shaft are connected via a link mechanism for rotating the sub gear shift shaft around the axis of the sub gear shift shaft as the main gear shift lever swings around the horizontal axis. In addition, a cam mechanism is provided between the sub-transmission shaft and a shift fork externally fitted to the sub-transmission shaft, the cam mechanism sliding the shift fork as the sub-transmission shaft rotates.

[0006]

As shown in FIG. 2, the shifting lever 7 has a horizontal axis X ₁
It is designed so that it can be operated in four steps around it. The two speed change shafts 5a and 5b for main speed change are selected by the operation of these four steps, and the two speed change shafts 5a and 5b for the main speed change are selected by the rocking operation around the vertical axis Y ₂ . The shift shaft 5a or 5b is slid. Then, the sub-transmission shaft 6 is rotated via the link mechanism 8 in accordance with the swing operation around the horizontal axis X ₁ , and the shift fork externally fitted to the sub-transmission shaft 6 is rotated in accordance with the rotation of the sub-transmission shaft 6. 6a is slid through the cam mechanism 9.

That is, when the shift lever 7 is operated upward from the position shown by the solid line, that is, when the reverse shift shaft 5b is selected, the forward shift shaft 5a is selected and further moved upward. , The shift fork 6a for the auxiliary shift is switched from the low speed to the high speed via the link mechanism 8 and the cam mechanism 9 while the forward shift shaft 5a is selected, and when the shift fork 6a is operated further upward, the auxiliary shift enters the high speed. Leave
The reverse shift shaft 5b of the main shift is selected.

[0008]

As described above, the sub-transmission is performed by the link mechanism that rotates the sub-transmission shaft in association with the main transmission lever and the cam mechanism that slides the shift fork externally fitted on the sub-transmission shaft by the rotation of the sub-transmission shaft. Since the shift fork of the shaft is configured to slide, it becomes possible to operate the main transmission device and the sub transmission device without changing the gear shift lever, and the shift operation becomes excellent.

[0009]

EXAMPLES Examples of the present invention will be described below with reference to a walk-type cultivator.

As shown in FIG. 1, an engine 3 is provided at the front of a mission case 2 having wheels 1 for traveling, and an upper portion of the mission case 2 is maneuverable around the longitudinal axis Y ₁ in the longitudinal direction of the body. A walk-behind cultivator is provided with the handle 4.

The walk-type cultivator comprises a main transmission device and an auxiliary transmission device, and as shown in FIG. It has a shaft 5a, a reverse shift shaft 5b, and a sub-transmission shaft 6 capable of shifting in two high and low stages, and has four forward stages and four reverse stages.
It is configured to be capable of shifting in steps.

On the side surface of the transmission case 2, there is provided one shift lever 7 for operating the two shift shafts 5a, 5b for main shift and the sub shift shaft 6.

The shift lever 7 selects the two main shift gear shift shafts 5a and 5b in accordance with the swing operation around the horizontal axis X ₁ , and the shift lever 7 is operated by the swing operation around the vertical axis Y _2. The selected shift shaft 5a or 5b is operated to slide, and the sub-transmission shaft 6 is rotated via the link mechanism 8 in accordance with the swinging operation around the horizontal axis X ₁ , and the sub-transmission shaft 6 is rotated. The shift fork 6a externally fitted to the auxiliary transmission shaft 6 is slid by a rotation of the transmission shaft 6 via a cam mechanism 9 provided between the auxiliary transmission shaft 6 and the shift fork 6a.

[0014] That is, the reverse shift shaft 5b comprises 5b ₁ receives a pair of levers up and down, during which lever receiving 5a ₁ of the forward shift shaft is disposed, the shift lever 7 in the horizontal axis X ₁ around When operated in four stages, as shown by the solid line, the forward shift shaft 5a is selected from the state in which the speed change arm 7a is selecting the reverse shift shaft 5b, and further upward operation causes the forward shift shaft 5a to move. With the selection selected, the shift fork 6a externally fitted to the sub-transmission shaft 6 is switched from low speed to high speed via the link mechanism 8 and the cam mechanism 9, that is, when the shift lever 7 is operated to the third speed, the sub-transmission is changed. Shift fork 6a is switched from low speed to high speed,
Further, when it is operated upward, the reverse shift 5b of the main shift is selected while the sub-shift is still in high speed.

As shown in FIG. 6, the cam mechanism 9 comprises a pin 9a protruding from the sub-transmission shaft 6 and an inclined cam groove 9b formed on the inner surface of the boss portion of the shift fork 6a. Along with the rotation around the core, the ball detent mechanism 10 is slid in the axial direction against the biasing force of the ball detent mechanism 10.

As shown in FIG. 3, a guide plate 11 of the speed change lever 7 is provided with a gauge 12 which is linked to the speed change lever 7 and indicates the speed change operation position of the speed change lever 7.

The gauge 12 is rotatably supported on the side wall of the transmission case 2 via a spherical joint 14, and the upper side thereof is an arm portion 7b extending upward from the base end of the speed change arm 7a. Is provided in a state of penetrating a stay 13 pivotally connected about a horizontal axis X ₂ so as to move forward and backward in accordance with a swing operation of the speed change lever 7 around the horizontal axis X _1. It is configured to be tiltable and tiltable in the left-right direction in accordance with a rotation operation of the shift lever 7 around the vertical axis Y ₂ .

[Other Embodiment] In the above embodiment, the forward movement 4
Although the number of gears and the number of reverse gears are 4 as an example, the number of gears such as 6 forward gears and 2 reverse gears can be appropriately changed.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

1] Overall side view

FIG. 2 is a schematic side view showing a linkage between a shift lever and a link mechanism.

FIG. 3 is a side view showing a shift state.

FIG. 4 is a plan view showing a shift pattern.

FIG. 5 is a schematic plan view showing the linkage between the transmission arm and the transmission shaft.

FIG. 6 is a schematic plan view showing a cam mechanism.

[Explanation of symbols]

2 transmission case 5a main transmission shaft 5b main transmission shaft 6 sub transmission shaft 6a shift fork 7 main speed change lever 8 link mechanism 9 cam mechanism X ₁ horizontal axis Y ₂ vertical axis

Claims (1)

[Claims] 1. A walk-type work comprising a plurality of shift shafts (5a), (5b) for main shift and a sub-shift shaft (6) capable of shifting between high and low speeds on a side surface of a mission case (2). In the machine, the plurality of shift shafts (5a) and (5b) for main shift are selected in accordance with the swinging operation around the horizontal axis (X ₁ ) and the selected shift shaft (5a or 5b) is selected. The main transmission lever (7) and the sub-transmission shaft (6), which are slid along with the swinging operation around the vertical axis (Y ₂ ), are connected to the horizontal axis (X ₁ ) of the main transmission lever (7). The sub-transmission shaft (6) is linked to the sub-transmission shaft (6) via a link mechanism (8) that rotates the sub-transmission shaft (6) around the axis of the sub-transmission shaft (6) in accordance with the swinging of the sub-transmission shaft (6). Between the shift fork (6a) externally fitted to the sub-transmission shaft (6), the shift flap is rotated as the sub-transmission shaft (6) rotates. A shift operation structure for a walk-behind work machine provided with a cam mechanism (9) for sliding the fork (6a).