JPH0473437A - Overload preventing device - Google Patents

Abstract

PURPOSE:To obtain a large transmission torque with a small structure, improve reliability, realize cost reduction and facilitate reuse by fitting the first rotary body having a shaft part and the second rotary body having a hole part to each other so that the torque can be transmitted by the frictional force between the shaft part and the hole part. CONSTITUTION:The driving power of a driving device is transmitted to a driven device side through the frictional force between the hole part 11 of the first rotary body 1 and the shaft 21 of the second rotary body 2 which are fitted to each other. Since, in this case, the hole part 11 and the shaft part 21 are in the direct contact, the transmission torque capacity can be increased. While, if the transmission torque quantity exceeds a set torque limit, the hole part 11 and the shaft part 21 relatively slip, and a plunger 15 is pressed by a cam surface 22, and shifted to the innermost part side of a cylinder 14, and the oil in the cylinder 14 is introduced into an oil passage 13, and the oil introduced into an oil groove 12 is pressurized. Accordingly, the hole part 11 is pressed outwardly in the radial direction, and the inside diameter is spread, and the fitted state between the hole part 11 and the shaft part 21 is loosened, and the torque transmission between both is cut.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an overload prevention device, and more specifically, to an overload prevention device used for a drive shaft interposed between a drive device and a driven device to transmit torque. , relates to an overload prevention device that restricts transmission of torque exceeding a set value.

<Prior Art> Conventionally, for example, a drive shaft for a steel rolling mill is provided with an overload prevention device (torque limiter) to prevent torque exceeding a set value from being transmitted.

As the above-mentioned overload prevention device, for example, as shown in FIG. 3, there is provided one constructed of a coupling sleeve 91 and a shaft holding boss 92. This overload prevention device is the cylindrical portion 91a of the coupling sleeve 91,
It has a hollow structure, and the cylindrical part 91a is connected to the hole part 93.
The cylindrical portion 91 is interposed between the cylindrical portion 91 and the shaft portion 94.
Torque transmission between the hole 93 and the shaft portion 94 can be performed by filling the hollow portion 91c of a with pressure oil and expanding the cylindrical portion 91a.

In the above overload prevention device, the coupling sleeve 9
A shear tube 95 is screwed into the flange portion 91b of No. 1 to prevent leakage of oil filled in the hollow portion 91C. This shear tube 95 can leak the pressure oil filled in the hollow portion 91c by breaking the protrusion 95g at the tip. On the other hand, the shaft presser boss 92 is fixed to the shaft portion 94 so as to be able to rotate integrally therewith, and a projection 95a of the shear tube 95 is introduced into a shear lug 92a provided at the upper end thereof.

When the transmitted torque exceeds the set torque limit, the coupling sleeve 91 and the shaft portion 94 slip relative to each other, and the protrusion 95a of the shear tube 95 or the shaft portion 9
Shear lug 92a of shaft presser boss 92 fixed to 4
disconnected by.

As a result, the oil filled in the hollow portion 91c flows out, the cylindrical portion 91a of the coupling sleeve 91 contracts, and torque transmission is cut off.

<Problems to be Solved by the Invention> The overload prevention device having the above configuration has the cylindrical portion 91a of the coupling sleeve 91 interposed between the hole portion 93 and the shaft portion 94, so that the above-mentioned problems can be solved. Compared to the case where the hole portion 93 and the shaft portion 94 are brought into direct frictional contact, the transmission torque capacity is smaller, and in order to obtain the desired transmission torque capacity, there is a problem that the entire size must be increased.

Further, as described above, the cylindrical portion 91a of the coupling sleeve 910 is interposed between the hole portion 93 and the shaft portion 94;
Since the inside of the cylindrical portion 91a is filled with pressure oil, calculation of the transmission torque capacity becomes complicated and difficult, and the actual transmission torque capacity differs greatly from the designed transmission torque capacity, preventing overload. There was a problem that the reliability was inferior.

Furthermore, there were also problems in that the structure was complicated, the manufacturing time was labor-intensive, and the manufacturing cost was high.

In addition, in order to reuse the torque transmission after cutting off the torque transmission, it is necessary to fill the hollow part 91c of the coupling sleeve 91 with oil and replace the shear tube 95, which is a hassle. There was a problem.

This invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an overload prevention device that is small in size, has a large transmission torque capacity, is highly reliable, is inexpensive, and is easy to reuse. With the goal.

<Means for Solving the Problems> The overload prevention device of the present invention for achieving the above object includes a first rotating body having a shaft portion and a second rotating body having a hole portion.
The rotating body is arranged rotatably around the same axis with the shaft portion and the hole fitted together so that torque can be transmitted by frictional force, and the shaft portion and the hole portion are fitted together so as to be rotatable around the same axis. an oil groove is provided in the rotating body, and an oil passage communicating with the oil groove and a cylinder communicating with the oil passage are provided in one of the first rotating body and the second rotating body, and the oil hole, the oil passage, and a cylinder are each filled with oil, and a plunger for pressurizing oil is inserted into the cylinder, and the other rotating body has a cam surface that presses the plunger as the two rotating bodies rotate relative to each other. It is characterized by forming a

According to the overload prevention device configured as described above, torque is transmitted by directly fitting the shaft portion of the first rotating body and the hole portion of the second rotating body, so that a large transmission torque capacity is achieved. In addition, since the mechanism of torque transmission is simple, the transmitted torque capacity can be easily and accurately determined by calculation.

Further, when the transmission torque capacity exceeds the set torque limit, the first rotating body and the second rotating body rotate relative to each other, and the plunger is pressed by a cam surface provided on one of the rotating bodies, The oil filled in the cylinder, oil passage, and oil groove is pressurized by the pressing action of the plunger. Here, since the oil groove is formed on the fitting surface between the shaft and the hole, the hole expands due to the pressure of the oil.
As a result of the loosening of the fit between the hole and the shaft, torque transmission is cut off. Thereafter, by returning the relative positions of the first rotating body 1 and the second rotating body 2 to their original positions, torque transmission can be performed again.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing examples.

FIG. 1 is a sectional view showing an overload prevention device of the present invention. The overload prevention device includes a first rotating body 1 connected to an output shaft of a drive device (not shown) and a second rotating body 2 connected to an input shaft of a driven device.
2 are arranged rotatably around the same axis 1.

A tapered hole 11 is formed in the first rotating body 1 , and a tapered shaft 21 that matches the hole 11 is formed in the second rotating body 2 . The hole portion 11 and the shaft portion 21 are arranged so that torque can be transmitted by frictional force.
They are firmly fitted together by interference fit. The two are fitted together by shrink fitting or press fitting. An oil groove 12 is formed on the inner periphery of the hole 11 and is open on the shaft 21 side. A plurality of oil grooves 12 are continuously formed in a spiral shape.

Further, inside the first rotating body 1, oil passages 13 are provided which communicate with both ends of the oil groove 12, respectively. The oil passage 13 includes a first oil passage 13a that is bored in the radial direction while communicating with the oil groove 12, and a second oil passage 13a that is bored parallel to the axis J from the end surface side of the first rotating body 1. and a passage 13b.

Furthermore, a second oil passage 13 is provided at the end of the first rotating body 1.
A cylinder 14 is formed in communication with b. The rear end of the cylinder 14 is open to the end surface of the first rotating body 1, and a plunger 15 is slidably fitted inside the cylinder 14. The rear end side of this plunger 15 is
It protrudes a predetermined length from the end surface of the first rotating body 1. Note that an O-ring 15a is interposed between the cylinder 14 and the plunger 15. The oil groove 12, oil passage 13, and cylinder 14 are filled with oil.

On the other hand, a cam surface 22 consisting of a curved surface is recessed in the second rotating body 2 so as to face the plunger 15. are in contact (see Figure 2).

A bearing 3 with a seal is interposed between the hole 11 of the first rotating body 1 and the shaft 21 of the second rotating body. This bearing 3 is for holding the first rotating body 1 and the second rotating body 2 on the same axis J during relative rotation between the two.

With the above configuration, the driving force of the drive device is transferred to the hole 21 of the first rotating body 1 and the shaft 21 of the second rotating body 2, which are fitted together.
It can be transmitted to the driven device side by the frictional force between. At this time, the hole 11 and the shaft 21
Since the two are in direct contact with each other, the transmission torque capacity can be increased compared to the case where there is an inclusion between the two. Furthermore, since there is no inclusion between the hole portion 11 and the shaft portion 21, the mechanism of torque transmission is simplified, so that the transmitted torque capacity can be determined easily and accurately by calculation. Furthermore, since the oil groove 12, oil passage 13, cylinder 14, etc. that constitute the above-mentioned overload prevention device are arranged inside the first rotary body 1, it becomes very compact with a small outer diameter.

On the other hand, when the transmission torque capacity exceeds the set torque limit, the hole portion 11 and the shaft portion 21 slip relative to each other, and accordingly, the plunger 15 is pressed by the cam surface 22, and the cylinder 14 is pressed. Moved to the inner part. Therefore, oil in the cylinder 14 is introduced into the oil passage 13, and the oil filled in the oil groove 12 is pressurized. As a result, the hole 11
The inner diameter is expanded by being pushed radially outward. As a result, the fitted state between the hole portion 11 and the shaft portion 21 is loosened, and torque transmission between the two is cut off. In addition, the drive device is
The drive is configured to be stopped immediately when the torque transmission is cut off. In addition, in order to cause the overload prevention device to transmit torque again, the plunger 15
The first rotating body 1 and the second
The relative position with respect to the rotating body 2 may be adjusted.

Note that the oil groove 12 may be provided on the shaft portion 21 side, or may be provided on both the hole portion 11 side and the shaft portion 21 side. In short, the oil groove 12 only needs to be provided facing the fitting surface B between the hole part 11 and the shaft part 21.

In addition, the oil passage 13, cylinder 14, plunger 15
etc. may be provided on the second rotating body 5 side, and in this case, the cam surface 22 for suppressing the plunger 15 will be provided on the first rotating body 1 side.

Further, the bearing 3 may be implemented without being configured, and in this case, a sealing member such as an O-ring may be provided in place of the bearing.

In addition, various design changes can be made to the present invention, such as forming the hole portion 11 and the shaft portion 21 into a straight surface instead of a tapered surface.

<Effects of the Invention> As described above, according to the overload prevention device of the present invention, torque is transmitted by directly fitting the hole portion and the shaft portion, so that the transmitted torque capacity is increased. In addition, since the configuration is simple, the transmitted torque capacity can be easily and accurately determined by calculation. Therefore, the torque limit can be set accurately, and the reliability of overload prevention can be improved. In addition, it is very compact with a small outer diameter, has a simple structure, and is inexpensive.

In addition, reuse is possible simply by adjusting the relative positions of the first rotary body and the second rotary body in the rotational direction to their original positions, making it extremely convenient.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the overload prevention device of the present invention, FIG. 2 is a plan view of the main part, and FIG. 3 is a sectional view showing a conventional example. DESCRIPTION OF SYMBOLS 1... First rotating body, 11... Hole, 12... Oil groove, 13... Oil passage, 14... Cylinder, 15...
Plunger, 2... Second rotating body, 21... Shaft part, 2
2...Cam surface, J...axis line, B...fitting surface between hole and shaft 1--first rotating body 11... hole 12--oil groove 13... -Oil passage 14...Cylinder 15...Plunger 2--Second rotary body 21--Shaft 22--Cam surface 1--Axis Bo, 6th hole and shaft fit together Figure 2

Claims (1)

[Claims] 1. A first rotating body having a shaft portion and a second rotating body having a hole portion are rotated around the same axis while the shaft portion and the hole portion are fitted together so that torque can be transmitted by frictional force. an oil groove is provided along the fitting surface of the shaft portion and the hole portion, and one of the first rotating body and the second rotating body is provided with an oil groove;
An oil passage communicating with the oil groove and a cylinder communicating with the oil passage are provided, and the oil hole, the oil passage, and the cylinder are each filled with oil, and the cylinder is filled with oil.
An overload prevention device characterized in that a plunger for pressurizing oil is inserted, and the other rotating body is formed with a cam surface that presses the plunger as the two rotating bodies rotate relative to each other.