JPS5840334Y2 - Overload prevention safety device in power transmission mechanism - Google Patents

Description

[Detailed description of the invention] This invention is an overload prevention safety device for the power transmission mechanism.
More specifically, in a power transmission mechanism equipped with a drive shaft and a driven shaft that are connected to enable torque transmission, there is an overload prevention safety feature that causes the drive side to idle when an overload exceeding a certain limit is applied to the driven side. Regarding equipment.

For example, in an agricultural machine, the output shaft 1 (drive side) of a tractor and the input shaft 2 (driven side) of a working machine are connected via a universal joint shaft 4 including a universal joint 3 as shown in the first diagram to transmit power. It forms a mechanism.

However, if an overload is applied to the driven side due to the work equipment getting caught in a stone, etc., and the driven side stops rotating, there is a risk of damage to the work equipment or the universally connected shaft. It becomes necessary to limit the torque transmission from the driving side to the driven side of the transmission mechanism to a certain limit value, and for example, the connection between the yoke of the universal joint 3 on the right side of FIG. 1 and the input shaft 2 acts on the driven side. In order to cope with such overload, an overload prevention safety device A as shown in FIGS. 2 and 3 is used, for example.

FIGS. 2 and 3 show a universal joint yoke 5 provided between a universal joint yoke 5 as a connection part of one shaft of the universal connection shafts forming a power transmission mechanism and a fitting shaft part 6 as a connection part of the other shaft. An overload prevention safety device,
A cam protrusion 8 biased in the radial direction by a spring 7 is provided on the shaft portion 6, and the protrusion 8 is pressed and engaged with a cam surface 9 formed in the inner hole of the fitting yoke 5, so that the transmitted torque is constant. Torque is transmitted while maintaining the state shown in the second figure within the range of the limit value, and when an overload exceeding the limit value is applied to the driven side due to the work equipment on the driven side biting a stone, etc., the cam surface 9 pushes the cam protrusion 8 in the centripetal direction against the spring 7, causing the driving side to idle and keeping the torque transmitted to the driven side within a certain limit value.

However, this conventional structure requires a large number of processing steps and a large number of parts, resulting in very high costs and has drawbacks such as being troublesome to assemble.

In view of the above-mentioned points, this invention provides the above-mentioned device which has an extremely simple structure and is easy to assemble.In addition to the swivel connecting shaft between a tractor and a working machine, this device also provides a power transmission device where there is a concern that foreign objects may get caught. This allows it to be used in various types of mechanical devices.

To explain an embodiment, in FIGS. 4 and 5, a shaft 30 serving as a connecting portion between one shaft on the driving side and a driven side can be rotated into an inner hole of a shell body 31 serving as a connecting portion for the other shaft. φ is fitted, and parallel plane portions 32 are formed on both sides of the shaft 30.

The shell 31 includes a cylindrical portion and a cavity 33 that extends symmetrically on both sides of the cylinder so that the cross section is U-shaped.
A suppressing plate 34 is fitted within the shell body 31 so as to be movable in the radial direction of the shell body 31 so as to extend along the parallel plane portion 32 of the shaft 30, and a disc spring 35
The pressing plate 34 is urged in the axial direction of the shaft 30 using a biasing means such as the like.

That is, the shaft 30 and the shell 31 are connected to the parallel plane portion 32 of the shaft 30.
is clamped by a pressing plate 34 as shown in FIG.

If an overload exceeding the above-mentioned limit is applied to the driven side, such as when the work equipment on the driven side gets caught in a stone, the pressing plate 34 presses against the cylindrical surface of the shaft 30 against the pressing force of the disc spring 35. The shaft is pushed up as shown in FIG. 5, so that the drive-side shaft idles, and the torque transmission to the driven-side shaft is automatically kept within a certain limit value.

As shown in FIG. 6, if the shell body 31 is provided with an adjustment bolt 36 and a sliding seat plate 37, it becomes possible to arbitrarily adjust the biasing force of the pressing plate 34 by the disc spring 35.
The limit value of the transmitted torque can be changed arbitrarily.

Further, when the load acting on the shaft on the driven side reaches a certain limit value and the driving side starts to idle, and the press plate 34 is pushed up from the parallel plane part 32 of the shaft 30 to its cylindrical part, the press plate 34 is pushed up from the parallel plane part 32. 32, the cavity 33 of the shell 31
If there is a concern that the object may escape further, the pressing plate 34' may be formed into a U-shaped cross section as shown in FIG. 7 to increase the depth of engagement with the recess to prevent the pressing plate from tilting. What is necessary is to increase the thickness of the structure to prevent its tilting.

Furthermore, instead of combining the disc spring 35 and the pressing plate 34, a μ plate spring 34A can be used as shown in FIG.

In short, as the biasing means, a disc spring, a leaf spring, or any other suitable biasing means can be selected.

This invention has the above-mentioned structure, and since the processing part of the device only requires forming the parallel plane part of the shaft 30 and the cavity of the shell 31, the number of processing steps is significantly reduced compared to the conventional method, and the number of parts can be reduced. This makes processing and assembly easy, and the structure is simple, greatly reducing costs.Moreover, the disc spring, the suppression plate, and the connecting part of one shaft are connected to the shell as the connecting part of the other shaft. Since it has a structure that is internally built into the body, when it is used, for example, as a connecting shaft of an agricultural machine, there is no chance that dried grass or the like will get caught up in it and impede the operation of the disc spring, pressing plate, etc., and therefore no failure will occur.

In addition, since the pressure plate is pressed against the parallel plane part of the shaft, it can be used in any part such as the fitting part between the yoke and the shaft or the spline part of the connecting shaft, and is compact and can be used in various agricultural machines. In addition to the freely connecting shaft,
It can be used for general purposes as an overload prevention safety device for various power transmission mechanisms where there is concern about foreign matter getting caught.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a power transmission shaft, Fig. 2 is a vertical sectional view of the main part of a conventional device, Fig. 3 is a sectional view taken along the line ■■ in Fig. 2, and Fig. 4 is an embodiment of this invention. FIG. 5a is a cross-sectional view taken along the line ■-v in FIG. 4, FIG. 7 is a view corresponding to FIG. 5 of another embodiment, and FIG. 8 is a perspective view showing another example of the urging means. 30...Shaft (connection part of one shaft), 3F...
...Shell body (connection part of the other shaft), 32...-Parallel plane part, 34...Press plate, 35...
Belleville spring (biasing means).

Claims (1)

[Scope of utility model registration request] Overload in a power transmission mechanism in which the driving side shaft and the driven side shaft are connected so that torque can be transmitted up to a certain limit value and the driving side spins idle when a load exceeding a certain limit value is applied to the driven side. In a preventive safety device, the connecting part of the shaft on either the driving side or the driven side is formed with a cylindrical part and a shell that forms a U-shaped space that extends symmetrically on both sides of the cylindrical part. Parallel flat parts are formed on both sides of the connecting part of the shaft, and the connecting parts are rotatably fitted into the inner hole of the cylindrical part of the shell, and a pressing plate that presses the parallel flat parts is inserted into the U-shaped hole of the shell. An overload prevention safety device for a power transmission mechanism, which is provided with a biasing means that is movably fitted in the shell body in a radial direction and biases the pressing plate in the axial direction of the shaft fitted in the shell body.