JPS6025569Y2 - fatigue testing machine - Google Patents

Description

[Detailed explanation of the device] This device rotates an eccentric weight around the rotation axis, transmits the centrifugal force generated by the centrifugal force to the test piece, and repeatedly loads the test piece to test the degree of fatigue of the material. It is related to the testing machine.

Among the various mechanical properties of various materials, fatigue resistance is a property that must be considered important in design, etc., and various testing methods and fatigue testing machines are provided.

Among these, the above-mentioned testing machine has a relatively simple configuration as shown in FIG. 1, and is widely used.

That is, the test piece 1 is attached to the fixed part 10 via the chucks 2 and 3.
and the vibrating body 4, and a load is applied repeatedly by vertical vibration of the vibrating body 4.

The vibration of the vibrating body 4 is generated when the rotating shaft 6 passing through the vibrating body 4 rotates with an eccentric weight attached thereto.

The rotating shaft 6 is rotated by the output of an electric motor 8 via a transmission shaft 7, but this drive mechanism may be a belt drive mechanism.

Reference numeral 9 represents a leaf spring for supporting the vibrating body 4 while allowing its vertical vibration, and reference numeral 11 represents a coil spring.

By the way, when the eccentric weight has a fixed eccentric distance as shown in FIG. An impact overload exceeding the load value is applied.

This state is as shown in FIG. 2A.

Therefore, cracks may occur in the test piece due to this overload, and a normal test may not be possible.

A method has been proposed to solve this problem, such as a method in which the vibration of the vibrating body is manually blocked at the start of rotation, and the block is released after a certain period of time to prevent overload from being applied.

However, this method only blocks one direction, and therefore, although no overload occurs in one direction (upper side) as shown in Figure 2B, overload in the other direction (lower side) exceeds the predetermined load, which affects test accuracy. I have a problem.

In addition, manual operation is disadvantageous in that it cannot completely prevent the vibration of the vibrating body in the case of a highly rigid test piece, and furthermore, it may cause erroneous operation by the operator.

The fatigue testing machine provided here is an attempt to provide a testing machine that completely eliminates these conventional problems.

That is, the fatigue testing machine provided by this invention has an eccentric weight fitted and held in a guide frame so as to be movable inside the frame.
It consists of a moving weight that slides due to centrifugal force and an elastic body that controls the moving speed of this moving weight.When the eccentric weight starts rotating, the amount of eccentricity of the moving weight is reduced to prevent overload from occurring. This is what I did.

This invention will be described below with reference to embodiments shown in the drawings.

. FIGS. 3 to 6 show the structure according to this invention, and the eccentric weight body is clearly shown.

That is, 12 is a hollow cylindrical frame body which is screwed onto the rotating shaft 6, and a cap 13 is screwed onto one end of the frame body.

These constitute a guide frame. As shown in FIG. 6, a plurality of windows 12h are formed in this guide frame.

Reference numeral 14 denotes a movable weight fitted and held inside the cylindrical frame 12 so as to be movable in the axial direction thereof, and the weight 14 has a central hole 14h.

The adjustment rod 15 passes through this central hole 14h.

The adjustment rod 15 has a flange 15F in the middle thereof, and this flange 15F contacts the left end surface (the end surface in the direction of movement due to centrifugal force) of the weight 14 to regulate the amount of movement of the weight 14.

Reference numeral 16 denotes an elastic body (compression spring) interposed between the cap 13 and the movable weight 14, and always urges the movable weight 14 in the direction of the rotation axis.

A threaded portion 15S' is provided on the right side of the adjustment rod 15, and an operating portion 15' is provided on the right end portion, and these are integrally formed.

This threaded portion 15S is screwed into the threaded portion 12S of the cylindrical frame body 12, and therefore, when the operating portion 15' is rotated, the adjustment rod 15 adjusts the position of the left-right displacing waist flange portion 15F.

This position adjustment prevents the movable weight 14 from moving further to the left, which means setting the set load value.

If these points are explained according to the drawings, the state shown in FIG. 3 is that the flange portion 15 is
This is the state in which F is moved to the far right.

Next, the flange portion 15F is set at a position corresponding to the set load value (FIG. 4).

In this state, the guide frame starts rotating.

Then, at the start, the eccentricity of the weight 14 is extremely small, and no overload C is applied to the test piece.

As the rotation progresses, the movable weight 14 receives the action of centrifugal force and gradually moves to the left (in the direction of the arrow) under the pressure of the compression spring 16, and the repetitive load increases until the final setting is reached. The load value is reached.

At this time, the weight 14 reaches the right side of the flange 15F, as shown in FIG.

While the weight 14 is moving, the compression spring 16 acts as a buffer and the moving speed is controlled.

Therefore, with the above configuration, the repeated load applied to the test piece 1 at the start of the test is shown in FIG.

The result is as follows. Furthermore, when the rotation of the eccentric weight is stopped (the test is completed), the compression coil spring 16 loses the centrifugal force of the moving weight, so it pushes the moving weight 14 in the direction of the rotation axis before starting the test (Fig. 4). This eliminates the need to return the movable weight to its original position (to the right end of the chamber).

Although this invention is characterized by the configuration as described above, it is not limited to these descriptions and drawings.

In particular, the shape of the cylindrical frame and the shape of the guide frame including these are not limited to being cylindrical.

That is, it would also be possible to simply provide a frame with several guide rods.

Further, as for the means for setting the set load value, instead of using the adjusting rod as shown in the illustrated example, there is also a method in which an adjusting threaded rod is screwed in from the cap side and the tip of the adjusting screw is brought into contact with the tip end surface of the movable weight.

This idea is as described in detail above, so the load value at the start of rotation of the eccentric weight has a small eccentricity, so there is no overload with respect to the set load value, and no cracks occur on the test piece at the time of startup. As shown in FIG. 7, the load value can be gradually increased to reach the set value without any problems occurring, ensuring a highly accurate test.

In addition, it has a simple configuration using a moving weight, exhibits the above effects, is inexpensive, and improves test accuracy.

Another great advantage is that it can be easily attached to existing testing machines.

[Brief explanation of the drawing]

Fig. 1 is a diagram schematically showing the configuration of a conventional testing machine, Fig. 2 is a characteristic diagram of the conventional testing machine, and Figs. Fig. 7 shows the characteristics of the test machine of this invention. 1...Test piece, 2...Chuck, 3.
... Chuck, 4 ... Vibrating body, 5 ...
...Eccentric weight, 6... Rotation axis, 7...
・Transmission shaft, 8... Electric motor, 9... Leaf spring, 10... Fixed part, 11... Coil spring, 12... Cylindrical Frame body, 13... Cap, 14... Moving weight, 15...
Adjustment rod, 16... Compression.

Claims (1)

[Scope of utility model registration request] In a testing machine that tests the degree of fatigue of a material by transmitting centrifugal force generated in a direction perpendicular to the rotational axis to the test piece when an eccentric weight is rotated around the rotational axis, the test piece is repeatedly loaded. A guide frame in which a weight is connected to a rotation shaft with its axis arranged in a direction perpendicular to the rotation axis; A moving weight that moves in the direction of the axis of the guide frame in response to centrifugal force generated by rotation, and is interposed between the guide frame and the moving weight, and always urges the moving weight towards the axis of rotation. A fatigue testing machine characterized by having an elastic body and a set load adjustment mechanism that limits the amount of movement of a movable weight.