JPH046482Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tilling claw attached to the drive shaft of a tilling device, and more specifically to a halberd-shaped tilling claw that has been processed in areas where concentrated stress is applied during tilling work. This is related.

Conventionally, as shown in FIGS. 1 and 2, for example, a tilling claw 1 has a blade body 7 integrally connected to a mounting part 3, and a blade part 11 and a back part 15 on this blade body 7. is formed. The back surface portion 15 of the blade body 7 and the attachment portion 3 are continuously provided with an edge portion 17 cut at a right angle. Therefore, due to the resistance of the tilling claws 1 when raising the soil, stress concentration occurs on the opposite side of the attachment part 3 where the blade part 11 starts, that is, on the large curved part 9 of the back part 15, and the back part 15 Edge 17
There were cracks in the. (Referring to FIG. 9, which is a computer-generated stress analysis diagram, this curved portion 9
It can be seen that stress is concentrated at ) This crack is
Although it is not visible at first, stress concentration occurs again in this area, and it gradually increases towards the blade body and back area. When a sharp resistance is applied to the tip of the blade of a tiller with such a crack, the tiller may break off from the edge of the crack and fall off. When the nails fall off, they remain sharp in the field, posing a risk of injury to feet when planting rice or weeding.

The present invention was created in order to solve the above-mentioned conventional drawbacks, and the blade body and the blade part are integrally formed in the mounting part, and between the mounting part and the edge of the blade body, By chamfering or rounding at least the curved part between the back surface of the blade and the attachment part, it is intended to prevent cracking due to stress concentration on the attachment part and the edge of the blade. .

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

As shown in FIGS. 3 and 4, reference numeral 1 denotes a tilling claw that can be attached to a drive shaft of a tilling device to a claw shaft having a claw attachment opening. The claw attachment port has
Insert the mounting part 3 and attach the pin to the connection port 5 (not shown)
is inserted. The blade body 7, which is integrally formed with the mounting portion 3, is attached to the mounting portion 3 in the traveling direction.
It has a curved part 9 that is more curved and receded, and of this curved part 9, especially the attachment part 3 where the blade 7 starts is the most curved part. Moreover, the tip portion 13 of the blade body 7 is curved to one side. The curved edges 17 (see FIG. 1) between the back surface 15 of the blade 7 and the mounting portion 3 are the curved edges 17 between the blade 7 and the back surface 15 on both sides (see FIG. 4).
Both edges are chamfered, and the next one is rounded. The other type is one in which the entire blade body 7 and back surface portion 15 on both sides are rounded.

In the above configuration, the tilling claw 1 performs soil tilling work by rotating the blade portion 11 forward. At this time, stress concentration is applied to the back surface portion 15 and the edge portion 17 of the attachment portion 3 of the blade body 7 due to the repulsive force from the soil applied to the blade portion 11 and the end portion 13 of the blade portion 11 . Blade body 7
For the stress concentration transmitted by both edges 17,
Since it is chamfered, the occurrence of cracks on the edge 17 is suppressed. Furthermore, if both edges 17 are rounded, or from both edges 17 to the back surface 15, the entire back surface 15 becomes rounded, further suppressing the occurrence of cracks.

By the way, the tilling claws receive a soil tilling reaction force during tilling, and this soil tilling reaction force can be broken down into a force applied from the direction of rotation of the tilling claws and a force applied from lateral to this rotation direction. The fatigue test for the force applied from the direction of rotation is performed as an impact drop cyclic fatigue test. This test is as shown in Figure 7.
Cultivating claw 1 with mounting part 3 fixed to the jig at an angle of 60°
A weight with a weight of 17.3 kg suspended from a wire is dropped from a height of 1.4 m onto the blade part 11 of the blade, and the fatigue fracture results at this time are shown in the graph shown in Fig. 5.

Note that the potential energy of the size and height of the weight is calculated from the horsepower of a commonly used engine, and can be changed as appropriate.

In addition, since the tip of the nail is curved, the angle of the load applied to the nail is set at a 60° angle, taking into account the direction in which the load will be applied from the position in the soil.

Next, a fatigue test for force applied from the side in the direction of rotation is performed as a 30 mm lateral push repeated fatigue test. In this test, as shown in Fig. 8, a pneumatic cylinder was used to press the tip 13 of the tiller claw 1, which has the attachment part 3 attached to the jig, from the lateral (horizontal) direction and bend it by 30 mm. This is done repeatedly, and the fatigue failure results at this time are as follows:
The graph will look like the one shown in the figure. The amount of pressure is 30mm
In addition to 20 mm and 40 mm, tests were also conducted, but these have been omitted.

Therefore, as can be seen from these fatigue test results (Figs. 5 and 6), those with a rounded part continuous from the attachment part of the naginata-type tilling claw to the back part of the blade body have a rounded part. The fatigue strength is clearly improved compared to the one without the provision, that is, the durability is improved.

Note that both types of fatigue failure are determined based on whether or not the tilling claws have broken. The background to this is as follows.

In other words, the average area owned by a farmer is 300 are (3 town walk)
If this farmer plows the field three times on average, the operating time of the tractor will be 30 are x 30 minutes (10 are / 30 minutes) = 900 minutes 3 plowing/year = 900 minutes x 3 times = 2700 minutes , becomes.

Since the rotation speed of the nail shaft is 250 rpm on average, the nail is driven into the soil 2,700 minutes x 250 rpm = 675,000 times a year.

When the nail is driven into the soil, a load and a release force are applied to the nail. In other words, compressive and tensile loads act alternately.

When metal materials are subjected to repeated work, they eventually break down. This is called material fatigue, and breakage occurs due to this fatigue.

When developing tiller claws, it is necessary to fully understand this condition and ensure quality.

For this reason, we study the shape by finding the relationship between the repeated stress and the number of repetitions.

Therefore, in the present invention, when the tilling claw 1 is manufactured and at the same time chamfered or rounded, the blade body 7
The entire edge 17 of the mounting portion 3 is then processed. However, when processing the completed tilling claw 1, the edge 1 which is the curved part 9 of the attachment part 3 from the blade 7
7, that is, the back surface portion 15 where the blade portion 11 starts from the attachment portion 3 is processed. When applying the above chamfering or rounding to a part of the edge 17,
Processing is performed gradually from the beginning of processing without creating a step between the processed and unprocessed parts.

As described above, according to the present invention, by providing the chamfer or radius, that amount, that is, the thickness is eliminated. This lost meat is a small amount in one claw, but in the rotary as a whole with the tilling claw attached, it becomes a mass, reducing driving horsepower, saving fuel consumption, and reducing vibration.

It is also desirable to make the tilling claws as thin as possible to improve their ability to cut into the soil.
The chamfer or radius is provided between the back surface portion of the blade body and the mounting portion and on the blade side in the thickness direction of the blade body. That is, the blade side in the thickness direction of the blade body is the side that receives a large compressive force from the soil when the blade part of the blade cuts into the soil, and is the weakest part. (Refer to Figure 9) Focusing on this weak part, chamfering or rounding is provided to increase the strength of the weakest part, and the overall thickness can be reduced based on that part. When looking at the rotary as a whole, the cutting performance of the entire number of tilling claws is improved, driving horsepower can be reduced, fuel consumption can be saved, and vibration can be reduced. In addition, since the cutting ability is improved, more soil can be tilled, making it possible to create a high-quality field, and the plowing ability is also good.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention.
The figure is a perspective view of the main parts of a conventional tilling claw, FIG. 2 is a sectional view of a conventional curved part, FIG. 3 is an overall perspective view of the tilling claw of the present invention, and FIG. 4 is a curved part of the present invention. Figure 5 is a graph showing the impact drop cyclic fatigue test results, Figure 6 is a graph showing the 30 mm horizontal push cyclic fatigue test results, Figure 7 is a schematic explanatory diagram showing the impact drop test method, Figure 8 is a graph showing the impact drop cyclic fatigue test results. The figure is a schematic explanatory diagram showing the lateral push test method, and FIG. 9 is a stress analysis diagram of the claw. 3... Mounting part, 7... Blade body, 9... Curved part, 1
1...blade part, 15...back part, 17...edge part.

Claims (1)

[Scope of utility model registration request] In a naginata-type plowing claw that has a mounting part and a blade body, and the blade body is curved from the mounting part toward the back side of the blade body, a continuous part from the mounting part to the back side of the blade body. A naginata-shaped plowing claw characterized by having a chamfer or radius on the blade side in the thickness direction of the blade.