JP7632213B2 - Chipping test method and chipping test device - Google Patents

Description

This disclosure relates to a chipping test method and a chipping test device.

Since moving objects such as automobiles may be hit by flying stones, parts mounted on moving objects are required to have high durability. Chipping tests are known as a method for testing the durability of this type of part. Chipping tests are also called flying stone tests or Gravelo tests, and involve firing projectiles such as stones, sand, metal pieces, or ceramic pieces under predetermined test conditions, colliding them with a test object, and evaluating the extent of damage to the test object.

As a technique for carrying out this type of chipping test, for example, the devices described in Patent Documents 1 and 2 are known. Patent Document 1 describes a flying stone test device that includes a pair of upper and lower tires, a rotation drive mechanism that rotates the pair of upper and lower tires, and a flying stone guideway that supplies flying stones between the pair of upper and lower tires, and that accelerates the flying stones using the rotating pair of upper and lower tires to collide with the test object.

Patent document 2 describes a flying stone testing machine that includes an injection tube, an injection nozzle that injects compressed air from the base end of the injection tube, and a supply pipe that is erected on the injection tube, and that supplies flying stones to the inside of the injection tube through the supply pipe and supplies compressed air from the injection nozzle to launch the flying stones from the tip of the injection tube.

JP 2008-58042 A Patent No. 6064013

In recent years, with the improvement of the performance of moving objects, the durability required for parts has also increased, and there is a demand for projectiles to collide with test objects at high speeds. Here, the injection tube described in Patent Document 2 is directly connected to the supply pipe without using joints, and is therefore considered to be made of a rigid body such as metal. When compressed air is injected inside such an injection tube, the projectile (flying stone) is accelerated inside the injection tube as the internal pressure increases, and the projectile collides with the inner wall of the injection tube. If the projectile is rapidly accelerated inside the injection tube in order to launch it at high speed, the impact when the projectile collides with the inner wall of the injection tube becomes large, and damage such as cracks or chips may occur to the projectile inside the chipping test device. If damage occurs to the projectile, the kinetic energy of the projectile colliding with the test object decreases, and the predetermined test conditions of the chipping test may no longer be met.

Therefore, the present disclosure aims to provide a chipping test method and chipping test device that can prevent damage to the projectile.

The chipping test method according to one embodiment is carried out using a chipping test device that launches a projectile from the tip of an elastic cylindrical body (having elasticity and extending between a base end and a tip end). The chipping test method includes the following steps (1) and (2).
(1) Moving the projectile at a first velocity to an acceleration start position between the base end and the tip end.
(2) A step of accelerating the projectile disposed at the acceleration start position to a second velocity faster than the first velocity and launching the projectile from the tip of the elastic cylindrical body.

In the chipping test method according to the above aspect, the projectile is moved at a relatively slow first speed to an acceleration start position between the base end and tip end of the elastic cylinder, and then the projectile is accelerated to a relatively fast second speed within the elastic cylinder and fired from the tip end of the elastic cylinder. As described above, since the projectile is accelerated inside the elastic cylinder, the accelerated projectile does not come into contact with a rigid body such as metal. Therefore, this method can prevent damage to the projectile within the chipping test device.

In one embodiment, the chipping test device further includes a compressed air supply source that supplies compressed air, and a pressure adjustment unit that is arranged between the compressed air supply source and the elastic cylinder and is capable of adjusting the secondary pressure on the elastic cylinder side, and the chipping test method may further include the following steps (3) to (5).
(3) A step of disposing a projectile at an initial position between the pressure adjusting portion and the elastic cylinder.
(4) A step of setting the secondary pressure of the pressure adjusting unit to a first pressure in order to move the projectile arranged at the initial position to the acceleration start position.
(5) A step of setting the secondary pressure of the pressure adjusting unit to a second pressure higher than the first pressure in order to accelerate the projectile placed at the acceleration start position within the elastic cylinder.
In this embodiment, the projectile is moved inside the elastic cylinder at a first speed and then accelerated to a second speed within the elastic cylinder, thereby preventing damage to the projectile within the chipping test device.

In one embodiment, the chipping test device further includes another elastic cylindrical body (having elasticity and extending between a base end and a tip end), a joint portion (having an inlet for injecting a projectile) connecting the tip end of the another elastic cylindrical body to the base end of the elastic cylindrical body, a compressed air supply source that supplies compressed air, and a pressure adjustment portion (arranged between the compressed air supply source and the another elastic cylindrical body) that can adjust the secondary pressure on the side of the another elastic cylindrical body, and the chipping test method may further include the following steps (6) to (8).
(6) A step of inserting a projectile into the insertion port.
(7) A step of moving the projectile by gravity to an acceleration start position within the elastic cylinder.
(8) A step of setting the secondary pressure of the pressure adjusting unit to a second pressure higher than the first pressure in order to accelerate the projectile placed at the acceleration start position within the elastic cylinder.
In this embodiment, the projectile is moved inside the elastic cylinder at a first speed and then accelerated to a second speed within the elastic cylinder, thereby preventing damage to the projectile within the chipping test device.

In one embodiment, the chipping test device further includes a compressed air supply source that supplies compressed air, and a pressure adjustment unit (arranged between the compressed air supply source and the elastic cylinder) that can adjust the secondary pressure on the elastic cylinder side, and the chipping test method further includes the following step (9).
(9) A step of correcting a launch velocity of the projectile. The step of correcting may be performed before the step of moving the projectile at the first velocity. The step of correcting includes the following steps (a) to (e):
(a) Obtaining a desired firing rate.
(b) determining a secondary pressure for accelerating the projectile to a desired launch velocity using correlation data representing the relationship between the secondary pressure of the pressure regulator and the launch velocity of the projectile;
(c) setting the secondary pressure of the pressure adjusting section to the determined secondary pressure and firing a projectile from the tip of the elastic cylindrical body.
(d) measuring the launch velocity of the projectile.
(e) A step of correcting the secondary pressure of the pressure adjusting unit so that the difference between the measured firing velocity and the desired velocity is reduced.
In this embodiment, the launch velocity of the projectile can be made closer to a desired velocity by correcting the secondary pressure of the pressure adjusting section.

In one embodiment, the correlation data may be data that represents the relationship between the secondary pressure of the pressure regulator and the minimum launch velocity of the projectile. By determining the secondary pressure of the pressure regulator using the correlation data that represents the relationship between the internal pressure of the elastic cylinder and the minimum launch velocity of the projectile, the launch velocity of the projectile is less likely to fall below the desired launch velocity.

The chipping test device according to one embodiment includes an elastic cylinder, a compressed air supply source, a pressure adjustment unit, a projectile insertion unit, and a control unit. The elastic cylinder has elasticity and extends between a base end and a tip end. The compressed air supply source supplies compressed air. The pressure adjustment unit is disposed between the compressed air supply source and the elastic cylinder, and enables adjustment of the secondary pressure on the elastic cylinder side. The projectile insertion unit places the projectile at an initial position between the pressure adjustment unit and the elastic cylinder. The control unit controls the secondary pressure of the pressure adjustment unit. The control unit sets the secondary pressure of the pressure adjustment unit to a first pressure so that the projectile moves at a first speed from the initial position to an acceleration start position between the base end and the tip end of the elastic cylinder. The control unit sets the secondary pressure of the pressure adjustment unit to a second pressure higher than the first pressure so that the projectile placed at the acceleration start position is accelerated to a second speed faster than the first speed and fired from the tip end of the elastic cylinder.

In the chipping test device according to the above aspect, the projectile is moved at a relatively slow first speed to an acceleration start position between the base end and tip end of the elastic cylinder, and then accelerated to a relatively fast second speed and fired from the tip end of the elastic cylinder. As described above, the projectile is accelerated inside the elastic cylinder, so the accelerated projectile does not come into contact with a rigid body such as metal. Therefore, this chipping test device can prevent damage to the projectile.

The chipping test device according to one embodiment may further include a rigid cylinder made of metal that connects the pressure adjustment section to the base end of the elastic cylinder. By including the rigid cylinder, the elastic cylinder, the projectile insertion section, and the pressure adjustment section can be easily connected.

The chipping test device according to one embodiment further includes a speed measurement unit that measures the launch speed of the projectile launched from the tip of the elastic cylinder. The control unit may then correct the secondary pressure for accelerating the projectile so that the difference between the two launch speeds becomes smaller. The two launch speeds are a predetermined desired launch speed and the launch speed of the projectile measured by the speed measurement unit. In this embodiment, the launch speed of the projectile can be brought closer to the desired speed by correcting the secondary pressure of the pressure adjustment unit.

A chipping test device according to another aspect includes a first cylinder, a second cylinder, a compressed air supply source, a pressure adjustment unit, a joint unit, and a control unit. The first cylinder extends between a base end and a tip end. The second cylinder has elasticity and extends between the base end and the tip end. The compressed air supply source supplies compressed air. The pressure adjustment unit is disposed between the compressed air supply source and the first cylinder, and is capable of adjusting the secondary pressure on the first cylinder side. The joint unit connects the tip end of the first cylinder to the base end of the second cylinder, and has an input port for inputting a projectile. The control unit controls the secondary pressure of the pressure adjustment unit. The projectile input from the input port is configured to move by gravity to an acceleration start position between the base end and the tip end of the second cylinder, and the control unit increases the secondary pressure of the pressure adjustment unit in order to accelerate the projectile arranged at the acceleration start position and launch it from the tip end of the second cylinder.

In the chipping test device according to the above aspect, the projectile inserted from the insertion port is moved by gravity to the acceleration start position, and the projectile placed at the acceleration start position is accelerated within the elastic cylinder and fired from the tip of the elastic cylinder. As described above, the projectile is accelerated inside the elastic cylinder, so the accelerated projectile does not come into contact with a rigid body such as metal. Therefore, this chipping test device can prevent damage to the projectile.

The chipping test device according to one embodiment may further include a rigid cylinder made of metal that connects the pressure adjustment unit to the base end of the first cylinder. By including the rigid cylinder, the first cylinder, the projectile insertion unit, and the pressure adjustment unit can be easily connected.

The chipping test device according to one embodiment may further include a speed measurement unit that measures the launch speed of the projectile launched from the tip of the second cylinder. The control unit may correct the secondary pressure for accelerating the projectile so that the difference between the two launch speeds becomes smaller. The two launch speeds are a predetermined desired launch speed and the launch speed of the projectile measured by the speed measurement unit. In this embodiment, the launch speed of the projectile can be brought closer to the desired speed by correcting the secondary pressure of the pressure adjustment unit.

Various aspects of the present disclosure can prevent damage to the projectile.

FIG. 1 is a diagram illustrating a chipping test device according to an embodiment. 1 is a flowchart illustrating a chipping test method according to an embodiment. FIG. 1 is a diagram showing the motion of a projectile. FIG. 1 is a diagram showing the motion of a projectile. FIG. 1 is a diagram showing the motion of a projectile. 13 is a flowchart showing a method for correcting a firing rate. FIG. 13 is a diagram showing an example of correlation data representing the relationship between the secondary pressure of a pressure regulating valve and the launch velocity of a projectile. FIG. 13 is a schematic diagram showing a chipping test device according to another embodiment. FIG. 1 is a schematic diagram showing a chipping test device used in comparative experimental examples. FIG. 13 is a diagram showing the mass ratio of a projectile before and after launch obtained in a comparative experimental example. FIG. 13 is a diagram showing the mass ratio of a projectile before and after launch obtained in an experimental example. FIG. 13 is a schematic diagram showing a modified example of a chipping test device.

Below, an embodiment of the present disclosure will be described with reference to the drawings. In the following description, identical elements or elements having the same functions will be given the same reference numerals, and duplicated descriptions will be omitted. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios and angles are not limited to those shown in the drawings. In the following description, the terms "upstream" and "downstream" are used based on the flow direction of compressed air from the compressed air supply source 31 described below.

Figure 1 is a schematic diagram of a chipping test device according to one embodiment. The chipping test device 1 shown in Figure 1 fires a projectile 5 at a test object to test the durability of the test object. Examples of the projectile 5 fired from the chipping test device 1 include stones, sand, metal pieces, and ceramic pieces.

As shown in FIG. 1, the chipping test device 1 includes a rigid cylinder 10, an elastic cylinder 20, a compressed air supply unit 30, a projectile insertion unit 40, and a control unit 50. The rigid cylinder 10 is a hollow tube made of a rigid material such as metal, and provides a part of the pipeline for launching the projectile 5. The base end 10a of the rigid cylinder 10 is connected to the compressed air supply unit 30, and the tip end 10b of the rigid cylinder 10 is connected to the base end 20a of the elastic cylinder 20.

The compressed air supply unit 30 supplies compressed air to the inside of the rigid cylinder 10 and the elastic cylinder 20. In one embodiment, the compressed air supply unit 30 includes a compressed air supply source 31, a pressure regulating valve 32, and an on-off valve 33. The compressed air supply source 31 is, for example, a compressor that supplies compressed air, and is connected to the base end 10a of the rigid cylinder 10.

The pressure regulating valve 32 is connected to the rigid cylinder 10 downstream of the compressed air supply source 31. The pressure regulating valve 32 is, for example, a pressure reducing valve, and adjusts the secondary pressure of the pressure regulating valve 32, i.e., the pressure on the downstream side (elastic cylinder 20 side), to a pressure lower than the primary pressure, i.e., the pressure on the upstream side (compressed air supply source 31 side). In other words, the pressure regulating valve 32 is disposed between the compressed air supply unit 30 and the elastic cylinder 20, and has the function of adjusting the secondary pressure on the elastic cylinder 20 side. The secondary pressure of the pressure regulating valve 32 is controlled by a control signal from the control unit 50.

The on-off valve 33 is connected to the rigid cylinder 10 downstream of the pressure regulating valve 32. The on-off valve 33 is configured to be able to switch between supplying and stopping the supply of compressed air to the elastic cylinder 20 by opening and closing the valve body. The opening and closing of the on-off valve 33 is controlled by a control signal from the control unit 50. The pressure regulating valve 32 and the on-off valve 33 constitute a pressure adjusting unit 35 that can adjust the secondary pressure on the elastic cylinder 20 side.

A projectile injection tube 43 is connected to a position between the base end 10a and the tip end 10b of the rigid cylinder 10. The projectile injection tube 43 extends upward from a midway position of the rigid cylinder 10 and is connected to the projectile injection section 40. The projectile injection section 40 includes a projectile tank 41 and a gate 42. The projectile tank 41 is connected to the projectile injection tube 43 and stores therein the projectile 5 to be projected at the test object 6. The top of the projectile tank 41 may be open, and the projectile 5 may be injected into the inside of the projectile tank 41 from the top opening.

The gate 42 is, for example, an on-off valve, and is provided between the projectile tank 41 and the rigid cylinder 10. The gate 42 is configured to be able to switch between supplying and stopping the supply of the projectile 5 into the rigid cylinder 10. The opening and closing of the gate 42 is controlled by a control signal from the control unit 50. When the gate 42 is opened, the projectile 5 stored in the projectile tank 41 passes through the gate 42 and falls into the rigid cylinder 10 through the projectile injection pipe 43. In the following description, the position in the rigid cylinder 10 where the projectile 5 supplied from the projectile tank 41 is placed is referred to as the initial position P1. The initial position P1 is a position in the rigid cylinder 10 that is predetermined by design, and is a position between the pressure regulating valve 32 and the elastic cylinder 20.

The elastic cylinder 20 is a hollow tube having elasticity, and together with the rigid cylinder 10, provides a conduit for launching the projectile 5. Examples of the elastic body constituting the elastic cylinder 20 include rubber and resin. For example, the elastic cylinder 20 is a high pressure resistant rubber hose. The elastic cylinder 20 has a base end 20a and a tip end 20b, and extends between the base end 20a and the tip end 20b. The base end 20a of the elastic cylinder 20 is connected to the tip end 10b of the rigid cylinder 10. In one embodiment, the base end 20a of the elastic cylinder 20 may be provided with a connecting fitting 25 that surrounds the outer circumferential surface of the elastic cylinder 20. The connecting fitting 25 and the tip end 10b of the rigid cylinder 10 are fitted together to detachably connect the rigid cylinder 10 and the elastic cylinder 20, which are made of different materials.

The tip 20b of the elastic cylinder 20 functions as an ejection port for ejecting the projectile 5. The tip 20b of the elastic cylinder 20 is disposed within the cabinet 52. The test object 6 is disposed inside the cabinet 52. The test object 6 is a test sample against which the projectile 5 is to be impacted, and is an automobile part, a railway part, an aircraft part, or the like. Examples of the test object 6 include, but are not limited to, an automobile radiator, glass, or soundproofing material.

The tip 20b of the elastic cylinder 20 is fixed in a position facing the test object 6. When compressed air is supplied from the compressed air supply unit 30, the projectile 5 is accelerated within the elastic cylinder 20 and fired from the tip 20b. The fired projectile 5 collides with the test object 6. The test object 6 that has been struck by the projectile 5 is removed, for example, from the cabinet 52 and the extent of damage is evaluated.

A reinforcing metal fitting 26 may be provided at the tip 20b of the elastic cylinder 20. The reinforcing metal fitting 26 surrounds the outer circumferential surface of the elastic cylinder 20 to reinforce the tip 20b of the elastic cylinder 20 and prevent damage to the tip 20b of the elastic cylinder 20 caused by the impact when the projectile 5 is launched.

In one embodiment, the chipping test device 1 may further include a speed measurement unit 54 that measures the launch speed of the projectile 5. The speed measurement unit 54 is an imaging device such as a high-speed camera, and is disposed close to the tip 20b of the elastic cylinder 20. For example, the speed measurement unit 54 takes high-speed images of the projectile 5 launched from the tip 20b of the elastic cylinder 20 from above or from the side, and measures the launch speed of the projectile 5 based on the travel distance and time of the projectile 5. The speed measurement unit 54 outputs the measured launch speed to the control unit 50.

The control unit 50 is a computer equipped with a processor, a memory unit, an input device, a display device, a communication device, etc., and controls the operation of the entire chipping test device 1. The control unit 50, for example, loads a program stored in the memory unit and executes the loaded program in the processor to realize various functions described below. The control unit 50 allows an operator to use the input device to input commands to manage the chipping test device 1, and also allows the display device to visualize and display the operating status of the chipping test device 1.

The control unit 50 is communicatively connected to the compressed air supply unit 30 and the projectile insertion unit 40, and controls the operation of the compressed air supply unit 30 and the projectile insertion unit 40. More specifically, the control unit 50 sends control signals to the compressed air supply source 31, the pressure regulating valve 32, the on-off valve 33, and the gate 42, and controls the operation or stop of the compressed air supply source 31, the secondary pressure of the pressure regulating valve 32, the opening and closing of the on-off valve 33, and the opening and closing of the gate 42.

Next, the functions of the control unit 50 will be described in detail, and a chipping test method using the chipping test device 1 will be described. Figure 2 is a flowchart showing a chipping test method according to one embodiment.

In this method, the control unit 50 first opens the gate 42 and inserts the projectile 5 stored in the projectile tank 41 into the rigid cylinder 10 (step ST1). At this time, as shown in FIG. 3, the projectile 5 falls through the projectile insertion tube 43 and is placed at the initial position P1 inside the rigid cylinder 10.

Next, the test object 6 is placed in the cabinet 52 (step ST2). The test object 6 is placed, for example, on a stage facing the tip 20b of the elastic cylinder 20. Next, the control unit 50 supplies compressed air from the compressed air supply source 31 to increase the primary pressure of the pressure regulating valve 32, and sets the secondary pressure of the pressure regulating valve 32 to the first pressure (step ST3).

Next, the control unit 50 opens the on-off valve 33. As a result, the internal pressure of the rigid cylinder 10 is increased to the first pressure, and the projectile 5 arranged at the initial position P1 moves to the acceleration start position P2 at a first speed corresponding to the first pressure due to the pressure, as shown in FIG. 4 (step ST4). The acceleration start position P2 is a position between the base end 20a and the tip end 20b in the elastic cylinder 20. The first speed is a speed slower than a second speed described later, for example, a speed of 100 km/h or less, or a speed of 10 km/h or less. By moving the projectile 5 from the initial position P1 to the acceleration start position P2 at a relatively slow first speed, the projectile 5 is prevented from colliding with the inner wall of the rigid cylinder 10 when passing through the inside of the rigid cylinder 10, causing damage to the projectile 5. When the projectile 5 reaches the acceleration start position P2, the on-off valve 33 is closed.

After the projectile 5 is positioned at the acceleration start position P2, the control unit 50 supplies compressed air from the compressed air supply source 31 to increase the primary pressure of the pressure regulating valve 32, and sets the secondary pressure of the pressure regulating valve 32 to a second pressure (step ST5). The second pressure is a pressure higher than the first pressure, and is determined according to the launch speed of the projectile 5. For example, the control unit 50 may store correlation data that represents the relationship between the secondary pressure of the pressure regulating valve 32 and the launch speed of the projectile 5, and use the correlation data to determine the second pressure that corresponds to the desired launch speed.

Next, the control unit 50 opens the on-off valve 33. This increases the internal pressure of the rigid cylinder 10 and the elastic cylinder 20 to a second pressure, which accelerates the projectile 5 placed at the acceleration start position P2 to a second speed corresponding to the second pressure within the elastic cylinder 20. The second speed is faster than the first speed, and is, for example, 120 km/h or more. As shown in FIG. 5, the projectile 5 accelerated to the second speed within the elastic cylinder 20 is launched from the tip 20b of the elastic cylinder 20 and collides with the test object 6 (step ST6).

Next, the degree of damage to the test object 6 is evaluated (step ST7). The evaluation of the test object 6 may be performed by removing the test object 6 from the cabinet 52 and visually evaluating the degree of damage to the test object 6, or by analyzing an image of the test object 6 captured by a high-speed camera or the like.

As described above, in the chipping test method shown in FIG. 2, the projectile 5 placed at the acceleration start position P2 is accelerated inside the elastic cylinder 20 to a relatively high second speed. Since the elastic cylinder 20 is made of an elastic body with low rigidity, even if the projectile 5 collides with the inner wall of the elastic cylinder 20 at high speed, damage such as chipping or cracking is unlikely to occur in the projectile 5. Therefore, a projectile 5 of a predetermined size or weight can be fired at high speed toward the test object 6.

The chipping test method according to one embodiment may further include a correction step of correcting the secondary pressure of the pressure regulating valve 32 so that the launch velocity of the projectile 5 approaches a desired velocity. FIG. 6 is a flowchart showing the step of correcting the launch velocity of the projectile 5. The correction step shown in FIG. 6 is performed before launching the projectile 5 at the test object 6, for example, before step ST1 of the chipping test method shown in FIG. 2.

In this correction method, first, the desired firing speed is obtained (step ST11). For example, the desired firing speed is input to the control unit 50 by an operator operating an input device. The desired firing speed is a speed that is determined in advance according to the test conditions of the chipping test.

Next, the control unit 50 opens the gate 42 and inserts the projectile 5 stored in the projectile tank 41 into the rigid cylinder 10 (step ST12). At this time, the projectile 5 passes through the projectile insertion pipe 43 and is placed at the initial position P1 inside the rigid cylinder 10. Next, the control unit 50 supplies compressed air from the compressed air supply source 31 to increase the primary pressure of the pressure regulating valve 32, and sets the secondary pressure of the pressure regulating valve 32 to the first pressure (step ST13).

Next, the control unit 50 opens the on-off valve 33. This increases the internal pressure of the rigid cylinder 10 to a first pressure, which causes the projectile 5, which is disposed at the initial position P1, to move to the acceleration start position P2 at a first speed corresponding to the first pressure (step ST14). When the projectile 5 reaches the acceleration start position P2, the on-off valve 33 is closed.

After the projectile 5 is placed at the acceleration start position P2, the control unit 50 supplies compressed air from the compressed air supply source 31 to increase the primary pressure of the pressure regulating valve 32 and sets the secondary pressure of the pressure regulating valve 32 to a second pressure corresponding to the desired launch speed (step ST15). Next, the control unit 50 opens the opening/closing valve 33. As a result, the internal pressure of the rigid cylinder 10 and the elastic cylinder 20 is increased to the second pressure, and the projectile 5 placed at the acceleration start position P2 is accelerated to a second speed corresponding to the second pressure in the elastic cylinder 20 by the pressure. The projectile 5 accelerated to the second speed in the elastic cylinder 20 is launched from the tip 20b of the elastic cylinder 20 (step ST16). At this time, the test object 6 is not placed in the cabinet 52, and the projectile 5 is launched toward, for example, a cushioning material.

Next, the speed measurement unit 54 measures the launch speed of the projectile 5 launched from the base end 20a of the elastic cylindrical body 20 (step ST17). For example, the speed measurement unit 54 photographs the launched projectile 5 at high speed with a high-speed camera, and measures the launch speed of the projectile 5 based on the travel distance of the projectile 5 per shutter speed.

Next, the control unit 50 compares the launch speed of the projectile 5 measured by the speed measurement unit 54 (hereinafter referred to as the "measured launch speed") with the desired launch speed, and determines whether there is a discrepancy between the two launch speeds (step ST18). For example, the control unit 50 determines that there is a discrepancy when the difference between the measured launch speed and the desired launch speed is equal to or greater than a predetermined threshold value.

If there is a discrepancy between the measured launch speed and the desired launch speed, the secondary pressure of the pressure regulating valve 32 is corrected (step ST19). For example, if the measured launch speed is slower than the desired launch speed, the second pressure is increased to bring the launch speed of the projectile 5 closer to the desired launch speed. Conversely, if the measured launch speed is faster than the desired launch speed, the second pressure is decreased to bring the launch speed of the projectile 5 closer to the desired launch speed. The control unit 50 then sets the secondary pressure of the pressure regulating valve 32 to the corrected second pressure.

Next, the control unit 50 opens the gate 42 and again puts the projectile 5 stored in the projectile tank 41 into the rigid cylinder 10 (step ST20). Next, the control unit 50 opens the on-off valve 33 and again launches the projectile 5 from the base end 20a of the elastic cylinder 20 (step ST16). Then, steps ST16 to ST20 are repeated until it is determined that there is no deviation between the measured launch speed and the desired launch speed. On the other hand, if it is determined that there is no deviation between the measured launch speed and the desired launch speed, the correction step is terminated. Then, the projectile 5 is projected at the test object 6 according to the chipping test method shown in FIG. 2. At this time, in step ST5 of FIG. 2, the secondary side pressure of the pressure regulating valve 32 is set to the corrected second pressure. As a result, the projectile 5 is launched at the desired launch speed.

In one embodiment, the memory unit of the control unit 50 stores correlation data representing the relationship between the secondary pressure of the pressure regulating valve 32 (i.e., the internal pressure of the elastic cylinder 20) and the launch speed of the projectile 5, and the control unit 50 may use the correlation data to determine the secondary pressure corresponding to the desired launch speed. If there is a discrepancy between the measured launch speed and the desired launch speed, the control unit 50 may correct the correlation data to bring the launch speed of the projectile 5 closer to the desired launch speed.

The standard correlation data F1 shown in FIG. 7 is an example of data that represents a standard relationship between the secondary pressure of the pressure regulating valve 32 and the launch velocity of the projectile 5. As shown in FIG. 7, the standard correlation data F1 is a model that represents the relationship between the secondary pressure of the pressure regulating valve 32 and the launch velocity of the projectile 5 as a linear function.

The control unit 50 fires the projectile 5 multiple times while changing the secondary pressure of the pressure regulating valve 32, measures the firing speed of the projectile 5 at that time using the speed measuring unit 54, and stores the firing speed in association with the secondary pressure. Next, the control unit 50 calculates the average value of the firing speeds fired multiple times for each secondary pressure. Then, the control unit 50 calculates an approximation line connecting the average values of the firing speeds for each secondary pressure, for example, by the least squares method, and generates average correlation data F2 representing the relationship between the secondary pressure and the firing speed of the projectile 5 based on the approximation line. For example, if there is a deviation between the measured firing speed measured when the standard correlation data F1 is used and the desired firing speed, the control unit 50 may determine the secondary pressure corresponding to the desired firing speed using the average correlation data F2 instead of the standard correlation data F1.

The control unit 50 may also calculate the minimum value of the firing speed of multiple shots for each secondary pressure. The control unit 50 may calculate an approximate straight line connecting the minimum values of the firing speed for each secondary pressure using, for example, the least squares method, and generate minimum correlation data F3 representing the relationship between the secondary pressure and the firing speed of the projectile 5 based on the approximate straight line. For example, when the secondary pressure of the pressure regulating valve 32 is set to a certain pressure and the projectile 5 is fired multiple times, if there is a large variation in the firing speed of the projectile 5 (for example, if the minimum value of the firing speed is 70% or less of the average value of the firing speed), the control unit 50 may determine the secondary pressure corresponding to the desired firing speed using the minimum correlation data F3 instead of the standard correlation data F1.

In a chipping test, a launch velocity that is lower than the desired launch velocity is not permitted, but a launch velocity that is higher than the desired launch velocity may be permitted. In this case, the launch velocity of the projectile 5 is less likely to fall below the desired launch velocity by determining the secondary pressure using the minimum correlation data F3.

Next, a chipping test device according to another embodiment will be described. FIG. 8 is a schematic diagram of a chipping test device 101 according to another embodiment. The chipping test device 101 differs from the chipping test device 1 in that the inserted projectile 5 is moved to the acceleration start position P2 by gravity. In the following explanation, differences from the chipping test device 1 will be mainly described, and overlapping explanations will be omitted.

As shown in FIG. 8, the chipping test device 101 includes a first cylinder (another elastic cylinder) 21, a second cylinder 22, and a joint 60 instead of the elastic cylinder 20. The first cylinder 21 and the second cylinder 22 are elastic hollow tubes, and together with the rigid cylinder 10, provide a conduit for launching the projectile 5. The base end 21a of the first cylinder 21 is connected to the tip end 10b of the rigid cylinder 10.

The joint 60 is made of metal and connects the tip 21b of the first cylindrical body 21 and the base end 22a of the second cylindrical body 22. The joint 60 is, for example, a three-way joint made of metal, and has a first port 60a, a second port 60b, and a third port 60c. The first port 60a is connected to the tip 21b of the first cylindrical body 21, and the second port 60b is connected to the base end 22a of the second cylindrical body 22. Here, the third port 60c may be located above the second port 60b.

The chipping test device 101 is provided with a projectile insertion section 140 instead of the projectile insertion section 40. The projectile insertion section 140 includes an insertion tube 45 for inserting the projectile 5 into the second cylinder 22. The insertion tube 45 is connected to the third port 60c of the joint section 60. When the projectile 5 is launched using this chipping test device 101, the projectile 5 is first inserted into the insertion tube 45. The projectile 5 inserted into the insertion tube 45 falls into the inside of the second cylinder 22 through the third port 60c, the second port 60b, and the base end 22a of the joint section 60 by gravity. That is, the third port 60c of the joint section 60 functions as an insertion port for inserting the projectile 5. The insertion tube 45 may be provided with a handle capable of switching between opening and closing the pipe in the insertion tube 45.

The projectile 5, which is inserted from the insertion tube 45 and passes through the joint 60, falls into the second tube 22 and moves by gravity to the acceleration start position P2 within the second tube 22. The acceleration start position P2 is a position between the base end 22a and the tip end 22b within the second tube 22.

The control unit 50 increases the secondary pressure of the pressure regulating valve 32 to the second pressure and opens the on-off valve 33. This increases the internal pressure of the second cylinder 22 to the second pressure, and this pressure accelerates the projectile 5 placed at the acceleration start position P2 to a second velocity corresponding to the second pressure within the second cylinder 22. The projectile 5 accelerated to the second velocity within the elastic cylinder 20 is fired from the tip 20b of the elastic cylinder 20 and collides with the test object 6. The test object 6 onto which the projectile 5 has been fired is removed from the cabinet 52, and the degree of damage caused by the collision of the projectile 5 is evaluated.

As described above, in the chipping test device 101, when the projectile 5 is launched, the projectile 5 is accelerated to the second speed in the second cylinder 22. The second cylinder 22 is made of an elastic body with low rigidity, and no metal parts are interposed between the base end 22a and the tip end 22b, so the projectile 5 does not collide with the metal parts at high speed. Therefore, damage such as chipping and cracking of the projectile 5 is suppressed. Thus, the projectile 5 of a predetermined size or weight can be launched at high speed toward the test object 6. In the above embodiment, the first cylinder 21 is made of an elastic body, but in one embodiment, the first cylinder 21 may be a metal pipe. As described above, in the chipping test device 101, the projectile 5 is accelerated to the second speed in the second cylinder 22, so that even if a metal pipe is used as the first cylinder 21, damage such as chipping and cracking of the projectile 5 can be suppressed.

Next, the effects of the chipping test device 1 will be explained based on experimental examples and comparative experimental examples, but the present invention is not limited to the experimental examples described below.

In the experimental example, the mass of the projectile 5 before and after it was fired from the chipping test device was measured, and the mass of the projectile 5 before and after firing was compared to evaluate the damage to the projectile 5. Granite gravel with a diameter of approximately 9 mm to 11 mm was used as the projectile 5. Other examples of projectiles that can be used include Oiso gravel and crushed granite.

In the experimental example, the projectile 5 was launched using the chipping test device 1 shown in FIG. 1. That is, the secondary pressure of the pressure regulating valve 32 was set to a first pressure, and the projectile 5 was moved at a low speed from the initial position P1 to the acceleration start position P2, and then the secondary pressure of the pressure regulating valve 32 was set to a second pressure, and the projectile 5 was accelerated to the launch speed within the elastic cylinder 20.

On the other hand, in the comparative experimental example, the projectile 5 was launched using the chipping test device 201 shown in FIG. 9. The chipping test device 201 shown in FIG. 9 includes a first cylindrical body 21, a second cylindrical body 22, and a connecting tube 62. The first cylindrical body 21 has a base end 21a and a tip end 21b, and the base end 21a is connected to the tip end 10b of the rigid cylindrical body 10. The second cylindrical body 22 has a base end 22a and a tip end 22b, and the tip end 22b functions as an ejection port for launching the projectile 5. The connecting tube 62 is made of metal and connects the tip end 21b of the first cylindrical body 21 and the base end 22a of the second cylindrical body 22. That is, in the chipping test device 201, a metal part is interposed between the first cylindrical body 21 and the second cylindrical body 22. In the comparative experimental example, the projectile 5 was accelerated to the launch velocity by increasing the secondary pressure of the pressure regulating valve 32 to the second pressure while the projectile 5 was placed at the initial position P1.

Figure 10 shows the mass of the projectile 5 before launch, the mass of the projectile 5 after launch, and the mass ratio of the projectile 5 before and after launch, measured in the comparative experimental example. As shown in Figure 10, in the comparative experimental example, the mass of the projectile 5 after launch was significantly reduced compared to the mass of the projectile 5 before launch. In particular, it was confirmed that the mass ratio of the projectile 5 was significantly reduced when the projectile 5 was launched at a high speed of 200 km/h or more. In the comparative experimental example, the projectile 5 placed at the initial position P1 was accelerated to the launch speed in one go, so the projectile 5 collided with the inner walls of the rigid cylinder 10 and the connecting tube 62 at high speed, causing damage such as cracks or chips in the projectile 5, which is thought to have resulted in a reduction in the mass of the projectile 5.

Meanwhile, FIG. 11 shows the mass of the projectile 5 before launch, the mass of the projectile 5 after launch, and the mass ratio of the projectile 5 before and after launch measured in the experimental example. As shown in FIG. 11, in the experimental example, even when the projectile 5 was launched at a high speed of 200 km/h or more, the mass ratio of the projectile 5 before and after launch was maintained close to 100%. In other words, it was confirmed that the projectile 5 hardly suffered any damage such as cracks or chips. In the experimental example, it is believed that this is because the projectile 5 was accelerated to the launch speed in the elastic cylinder 20 after being moved to the acceleration start position P2, and therefore the projectile 5 was prevented from colliding with the inner wall of the rigid cylinder 10 and the connecting tube 62 at high speed. From these results, it was confirmed that by launching the projectile 5 using the chipping test device 1, damage to the projectile 5 in the chipping test device 1 can be suppressed.

Thus far, we have described chipping test devices and chipping test methods according to various embodiments, but the invention is not limited to the above-described embodiments and can be modified in various ways without changing the gist of the invention.

For example, the chipping test device 1 shown in FIG. 1 includes one elastic cylinder 20, but the chipping test device 1 may include multiple elastic cylinders, which are connected to each other by metal joints. Even in this case, damage to the projectile 5 can be prevented by moving the projectile 5 at a low speed to a midway position of the elastic cylinder (the elastic cylinder arranged at the most downstream side) that provides the ejection port of the projectile 5 among the multiple elastic cylinders, and then accelerating the projectile 5 to the launch speed. The various embodiments described above can be combined to the extent that there is no contradiction.

In addition, in the chipping test device 1 shown in FIG. 1, the secondary pressure of the pressure regulating valve 32 is controlled by a control signal from the control unit 50, but the pressure regulating valve 32 does not have to be an electrically controlled valve. FIG. 12 is a schematic diagram showing a modified example of the chipping test device. The chipping test device 102 shown in FIG. 12 differs from the chipping test device 1 shown in FIG. 1 in that it has a manually operated pressure regulating valve.

As shown in FIG. 12, a branch pipe 12 branching from the rigid cylinder 10 is provided between the base end 10a and the tip end 10b of the rigid cylinder 10 of the chipping test device 102. The branch pipe 12 includes a first pipe 12a and a second pipe 12b arranged in parallel with each other. The first pipe 12a is provided with a pressure regulating valve 32a and an on-off valve 33a in this order from the upstream side. The second pipe 12b is provided with a pressure regulating valve 32b and an on-off valve 33b in this order from the upstream side. The pressure regulating valves 32a and 32b are manual pressure regulating valves, and the secondary pressure of the pressure regulating valve 32a is set to a first pressure, and the secondary pressure of the pressure regulating valve 32b is set to a second pressure higher than the first pressure. The first pipe 12a and the second pipe 12b merge with the rigid cylinder 10 downstream of the on-off valves 33a and 33b.

When a chipping test is performed using the chipping test device 102, the control unit 50 opens the on-off valve 33a and closes the on-off valve 33b to supply compressed air from the compressed air supply source 31. As a result, the compressed air supplied from the compressed air supply source 31 flows through the first pipe 12a of the branch pipe 12, and the pressure on the downstream side of the branch pipe 12 is increased to the first pressure. Accordingly, the projectile 5 arranged at the initial position P1 moves to the acceleration start position P2 at a first speed corresponding to the first pressure. Next, the control unit 50 closes the on-off valve 33a and opens the on-off valve 33b to supply compressed air from the compressed air supply source 31. As a result, the compressed air supplied from the compressed air supply source 31 flows through the second pipe 12b of the branch pipe 12, and the pressure on the downstream side of the branch pipe 12 is increased to the second pressure. Accordingly, the projectile 5 arranged at the acceleration start position P2 is accelerated to a second speed corresponding to the second pressure in the elastic cylindrical body 20. Then, the projectile 5 accelerated to the second velocity within the elastic cylinder 20 is launched from the tip 20b of the elastic cylinder 20 and collides with the test object 6. The branch pipe 12, the pressure adjustment valves 32a, 32b, and the opening/closing valves 33a, 33b constitute a pressure adjustment unit 35 that can adjust the secondary pressure on the elastic cylinder 20 side.

As described above, according to the chipping test device 102, the projectile 5 can be launched using the manual pressure regulating valves 32a and 32b. Manual pressure regulating valves are less expensive and have a longer life than motorized pressure regulating valves, so it is possible to improve the reliability of the chipping test device 102 while keeping manufacturing costs down. Such a chipping test device 102 is particularly suitable for use in harsh working environments.

1,101...chipping test apparatus, 5...projectile, 10...rigid cylinder, 20...elastic cylinder, 21...first cylinder (another elastic cylinder), 22...second cylinder (elastic cylinder), 31...compressed air supply source, 32...pressure regulating valve, 35...pressure regulating section, 40,140...projectile insertion section, 50...control section, 54...speed measuring section, 60...joint section, P1...initial position, P2...acceleration start position.

Claims (11)

A chipping test method using a chipping test device that has elasticity and extends between a base end and a tip end, and launches a projectile from the tip end of the elastic cylindrical body, comprising:
moving the projectile at a first velocity to an acceleration start position between the base end and the tip end;
accelerating the projectile disposed at the acceleration start position to a second speed faster than the first speed and launching the projectile from the tip end of the elastic cylindrical body;
A chipping test method comprising: The chipping test device includes:
a compressed air supply source for supplying compressed air;
a pressure adjusting unit disposed between the compressed air supply source and the elastic cylinder and capable of adjusting a secondary pressure on the elastic cylinder side;
Further comprising:
The chipping test method includes:
placing the projectile at an initial position between the pressure adjusting unit and the elastic cylinder;
setting the secondary pressure of the pressure adjusting unit to a first pressure in order to move the projectile arranged at the initial position to the acceleration start position;
setting the secondary pressure of the pressure adjusting unit to a second pressure higher than the first pressure in order to accelerate the projectile placed at the acceleration start position within the elastic cylindrical body;
The chipping test method of claim 1 further comprising: The chipping test device includes:
Another elastic cylindrical body having elasticity and extending between the base end and the tip end;
a joint portion that connects the tip end portion of the other elastic cylindrical body and the base end portion of the elastic cylindrical body, the joint portion having an injection port for injecting a projectile;
a compressed air supply source for supplying compressed air;
a pressure adjusting unit disposed between the compressed air supply source and the second elastic cylinder and capable of adjusting a secondary pressure on the second elastic cylinder side;
Further comprising:
The chipping test method includes:
inserting the projectile into the insertion port;
moving the projectile to the acceleration start position within the elastic cylinder by gravity;
increasing a secondary pressure of the pressure adjusting unit in order to accelerate the projectile disposed at the acceleration start position within the elastic cylindrical body;
The chipping test method of claim 1 further comprising: The chipping test device is
a compressed air supply source for supplying compressed air;
a pressure adjusting unit disposed between the compressed air supply source and the elastic cylinder and capable of adjusting a secondary pressure on the elastic cylinder side;
Further comprising:
The chipping test method further includes a correction step of correcting the launch velocity of the projectile,
The correction step includes:
obtaining a desired firing rate;
determining the secondary pressure for accelerating the projectile to the desired launch velocity using correlation data representing a relationship between the secondary pressure of the pressure regulator and the launch velocity of the projectile;
setting the secondary pressure of the pressure adjusting unit to the determined secondary pressure and launching the projectile from the tip of the elastic cylindrical body;
measuring the launch velocity of the projectile;
correcting the secondary pressure of the pressure regulator so that a difference between the measured firing speed and a desired speed is reduced;
Including,
2. The chipping test method of claim 1, wherein the step of correcting occurs before the step of moving the projectile at a first velocity. The chipping test method according to claim 4, wherein the correlation data is data representing the relationship between the secondary pressure of the pressure adjustment unit and the minimum launch velocity of the projectile. an elastic cylindrical body having elasticity and extending between a base end and a tip end;
a compressed air supply source for supplying compressed air;
a pressure adjusting unit disposed between the compressed air supply source and the elastic cylinder and capable of adjusting a secondary pressure on the elastic cylinder side;
a projectile insertion unit that places a projectile at an initial position between the pressure adjustment unit and the elastic cylinder;
A control unit that controls the pressure adjustment unit;
Equipped with
The control unit is
setting the secondary side pressure of the pressure adjusting unit to a first pressure so that the projectile moves at a first speed from the initial position to an acceleration start position between the base end and the tip end of the elastic cylindrical body;
In order to accelerate the projectile arranged at the acceleration start position to a second velocity faster than the first velocity and launch it from the tip end of the elastic cylindrical body, the secondary side pressure of the pressure adjusting unit is set to a second pressure higher than the first pressure.
Chipping test equipment. The chipping test device according to claim 6, further comprising a rigid cylinder made of metal that connects the pressure adjustment section and the base end of the elastic cylinder. A velocity measuring unit is further provided to measure the launch velocity of the projectile launched from the tip end of the elastic cylindrical body,
The control unit corrects the secondary pressure for accelerating the projectile so that the difference between a predetermined desired launch velocity and the launch velocity of the projectile measured by the velocity measuring unit becomes smaller. The chipping test device according to claim 6 or 7. a first cylindrical body extending between a base end and a tip end;
a second cylindrical body having elasticity and extending between the base end and the tip end;
a compressed air supply source for supplying compressed air;
a pressure adjusting unit disposed between the compressed air supply source and the first cylinder and capable of adjusting a secondary pressure on the first cylinder side;
a joint portion that connects the tip end of the first cylindrical body and the base end of the second cylindrical body, the joint portion having an injection port for injecting a projectile;
A control unit that controls the pressure adjustment unit;
Equipped with
The projectile inserted from the insertion port is configured to move by gravity to an acceleration start position between the base end and the tip end of the second cylinder,
The control unit increases the secondary pressure of the pressure adjustment unit in order to accelerate the projectile arranged at the acceleration start position and launch it from the tip end of the second cylinder.
Chipping test equipment. The chipping test device according to claim 9, further comprising a rigid cylinder made of metal that connects the pressure adjustment unit and the base end of the first cylinder. A velocity measuring unit is further provided to measure the launch velocity of the projectile launched from the tip end of the second cylindrical body,
The control unit corrects the secondary pressure for accelerating the projectile so that the difference between a predetermined desired launch velocity and the launch velocity of the projectile measured by the velocity measuring unit is reduced. The chipping test device according to claim 9 or 10.

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