JP2008170313A - Falling weight impact tester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a falling weight impact tester having a falling weight stopping means, capable of restricting compression of a specimen by stopping drop of a falling weight in the middle, and dispensing with the replacement of the falling weight stopping means in each test. <P>SOLUTION: This falling weight impact tester for performing an impact test of the specimen by the falling weight is equipped with a damper as the falling weight stopping means for restricting compression of the specimen by stopping the dropping falling weight in the middle. The falling weight impact tester has a characteristic, wherein the damper has a hydraulic cylinder equipped with a piston rod projecting upward, wherein a hydraulic oil is filled into an upper chamber on the upside of a piston and into a lower chamber on the downside thereof; a hydraulic oil communication circuit for communicating the hydraulic oil movably between the lower chamber and the upper chamber; a hydraulic oil narrowing means for restricting the moving quantity of the hydraulic oil in the hydraulic oil communication circuit; and a damper initial height resetting means for energizing so that the piston rod is positioned on the upper limit position, in a state where falling weight is not applied. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drop weight impact tester that performs an impact test of a specimen with a drop weight, and more particularly, to a drop weight impact test machine having a damper that stops the fall of the fall weight and restricts compression of the specimen.

  Conventionally, in order to perform an impact test on automobile parts and the like, as shown in a schematic explanatory view in FIG. 4, a falling weight (weight) 3 is lifted by an appropriate means (not shown), and a frame 2 of the falling weight impact tester 1 is used. After the stopper 4 is positioned at a predetermined height A, the stopper 4 is opened (broken line in FIG. 4), and the falling weight 3 is guided by a vertical slider (not shown) attached to the frame 2 in the figure. The sample is dropped as indicated by a white arrow and collided with a specimen 6 installed at a predetermined position on the mounting table 5 immediately below it, and the state of the specimen 6 is verified.

  However, if it is attempted to obtain a collision speed of 100 km / h by the free fall of the falling weight 3, the distance between the uppermost stop position A of the falling weight 3 and the contact position B of the falling weight 3 and the specimen 6, that is, The drop height a required about 40 m, and there was a problem that the drop weight impact tester was enlarged. Further, the fall height a is adjusted by the position of the stopper 4 and the setting of the mounting table 5 from the relationship between the set collision speed and the size of the specimen 4, and the adjustment is complicated.

  In order to solve the problem, as described in JP-A-2005-233910, an acceleration device 7 having a hydraulic drive system is provided on the frame 2, and the acceleration device 7 is used to apply a set hydraulic pressure to the hydraulic piston. It has been proposed to include an accumulator and to attach a falling weight holding device 8 capable of holding and separating the falling weight to the tip of the hydraulic piston 7a.

  If such an acceleration device 7 is used, the control device controls the hydraulic drive system of the acceleration device 7, the falling weight holding device 8 and the stopper 4, pressurizes the hydraulic piston 7 a downward with a predetermined pressure, and pushes the falling weight 3. At the same time, the stopper 4 is opened, the falling weight holding device 8 is released, and the falling weight 3 is pushed downward at a predetermined initial speed, so that the falling weight 3 is accelerated and dropped by the external force and its own weight due to the pushing, and the specimen 6, the drop height a can be shortened, and the collision speed can be easily adjusted by adjusting the extrusion speed of the acceleration device 7.

  On the other hand, even in such a case, the drop weight impact tester 1 is intended to measure the behavior of the specimen 6 when it receives an impact. There is a case where it is not necessary to apply compression to the case, and there is a case where it is necessary to conduct an impact test within a range where a certain compression state occurs. Further, when the automobile part or the like is used as the specimen 6, the falling weight 3 is, for example, a plane dimension of about 1 m × 1 m and a weight of about 1 ton, and when it is allowed to drop and collides with the specimen 6 without restriction, The drop weight 3 itself may be damaged or deformed, and in order to repeatedly use the drop weight 3, it has been required to buffer and stop the drop weight 3 to limit the compression of the specimen 6.

In such a case, as shown in FIG. 4, a lead column, an aluminum column, or the like is conventionally provided at a buffer material position C lower than the contact position B between the falling weight 3 and the specimen 6 by a compression test range height b. The top of the buffer material 9 is positioned (for example, four units are provided so as to surround the specimen 6 and the falling weights 3 are received at the four corners), and the falling weight 3 that has fallen collides with the specimen 6. After compression of the compression test range height b from the B position to the C position in the figure, the falling weight 3 collides with the cushioning material 9 and receives a damping action due to the compression of the cushioning material 9 to reduce the impact. It was made to stop at the falling weight stop position D below the buffer distance c. The buffer distance c and the falling weight stop position D are set in relation to the type and size of the cushioning material 9 based on the dimensions of the falling weight impact tester 1, the weight of the falling weight 3, the specifications of the specimen 6, the collision speed, and the like. However, in such a falling weight impact tester using the conventional means for stopping the falling weight 3 by the cushioning material 9, the cushioning material 9 such as a lead column or an aluminum column is naturally original after compressive deformation due to a collision. Therefore, replacement was required for each impact test, and there were many problems in terms of cost and work efficiency.
JP-A-2005-233910 (4th and 5th pages, FIGS. 1 and 2)

  The present invention has been made to solve the above-described problems of the conventional drop weight impact tester, and in particular, stopping the drop weight that can stop the fall of the drop weight and limit the compression of the specimen. It is an object of the present invention to provide a falling weight impact testing machine having a means and a falling weight stopping means that does not require replacement for each test as in the prior art.

  The present invention has been made to solve the above-described problems, and provides the following means (1) to (7), which will be described below in the order of the claims.

  (1) As a first means, in a falling weight impact testing machine that performs an impact test of a specimen with a falling weight, a damper is provided that stops the falling weight halfway and restricts compression of the specimen. The damper includes a piston rod that protrudes upward, a hydraulic cylinder that is filled with hydraulic oil in an upper chamber and a lower chamber on the upper side of the piston, and the hydraulic oil moves between the lower chamber and the upper chamber. The hydraulic fluid communication circuit that communicates with the hydraulic fluid, the hydraulic oil throttle means that restricts the amount of hydraulic fluid movement in the hydraulic fluid communication circuit, and the piston rod is positioned at the upper limit position without the falling weight. There is provided a falling weight impact tester characterized by having a damper initial height return means for biasing.

  (2) As a second means, in the falling weight impact tester of the first means, the hydraulic fluid communication circuit includes a lower chamber hydraulic fluid opening that opens from the lower chamber to the outside of the hydraulic cylinder, and the upper chamber A falling weight impact comprising: an upper chamber hydraulic oil opening that opens from the chamber to the outside of the hydraulic cylinder; and a communication conduit that communicates the lower chamber hydraulic oil opening and the upper chamber hydraulic oil opening. Providing a testing machine.

  (3) Further, as a third means, in the drop weight impact tester of the first means, the hydraulic fluid communication circuit is an outer part that forms a double pipe structure that surrounds the side surface of the hydraulic cylinder and closes the upper and lower ends. An annular sectional space formed between the cylinder and the outer peripheral surface of the hydraulic cylinder, a lower chamber hydraulic oil opening that opens from the lower chamber to the annular sectional space, and an upper that opens from the upper chamber to the annular sectional space. A falling weight impact testing machine characterized by comprising a chamber hydraulic oil opening is provided.

  (4) As a fourth means, in the drop weight impact tester of the second means, the hydraulic oil throttle means is constituted by a throttle valve interposed in the communication pipe line. Provide impact testing machine.

  (5) As a fifth means, in the falling weight impact test machine of the second or third means, the working oil throttle means is constituted by the lower chamber working oil opening. Provide a machine.

  (6) As a sixth means, in the drop weight impact tester according to any one of the first to fifth means, the damper initial height return means sets the piston rod to an upper limit in a state where the drop weight does not act. There is provided a falling weight impact tester characterized by comprising an urging force positioned at a position and a spring set to strengthen the urging force by lowering of the piston rod by the action of the falling weight.

  (7) As a seventh means, in the falling weight impact tester of any one of the first to fifth means, the damper initial height return means is located between the hydraulic oil throttle means and the upper chamber. The hydraulic cylinder is configured to include a scavenge tank that communicates with the hydraulic fluid communication circuit and encloses hydraulic oil and pressurized gas therein, and the hydraulic cylinder has a larger volume change of the lower chamber than the upper chamber volume change with respect to the lifting and lowering of the piston rod, The initial pressure of the pressurized gas is a pressure that acts on the hydraulic cylinder via the hydraulic oil in a state where the falling weight does not act, and positions the piston rod at its upper limit position, and the scavenge tank acts on the falling weight. The gas region of the pressurized gas is narrowed by the hydraulic oil that moves from the hydraulic cylinder to the scavenge tank when the piston rod descends due to Providing falling weight impact tester, characterized in that.

  (1) According to the first aspect of the present invention, the falling weight impact tester is configured as the first means, so that it can be used as a falling weight stopping means without any special operation. Since the damper returns to the initial damper height again, it will be ready for the next drop weight impact test, and it will not be necessary to replace or re-install the cushioning material, which is a means to stop the drop weight as in the conventional device. The burden of test cost and work efficiency of the impact test can be remarkably reduced.

  (2) According to the invention of claim 2, since the falling weight impact tester is configured as the second means, the effects of the invention of claim 1 can be obtained and a special structure is required for the hydraulic cylinder. In addition, the hydraulic fluid communication circuit can be simply configured.

  (3) According to the invention of claim 3, since the falling weight impact tester is configured as the third means, the function and effect of the invention of claim 1 are achieved and the structure of the hydraulic fluid communication circuit is integrated. A compact and compact aspect can be achieved. Moreover, when connecting a scavenge tank like invention of Claim 7, it becomes easy to connect by the large diameter communication part with little flow path resistance.

  (4) According to the invention of claim 4, since the falling weight impact tester is configured as the fourth means, the operational effect of the invention of claim 2 is achieved and the hydraulic oil throttle means is simply attached. It is done.

  (5) According to the invention of claim 5, since the falling weight impact tester is configured as the fifth means, the operational effect of the invention of claim 2 or claim 3 is obtained, and the lower chamber hydraulic oil is provided. The high pressure generated in the lower chamber at the time of damping action does not act on the outside of the opening, and the mechanical specifications of the falling weight impact tester such as a hydraulic fluid communication circuit can be reduced.

  (6) According to the invention of claim 6, since the falling weight impact tester is configured as the sixth means, the effect of the invention of any one of claims 1 to 5 can be achieved, and the damper Since the initial height return means is constituted by a spring, the device configuration can be simplified.

(7) According to the invention of claim 7, since the falling weight impact tester is configured as the seventh means, the function and effect of the invention of any one of claims 1 to 5 can be achieved and the damping can be achieved. After the action, the action of returning the damper position to the initial height is performed by the pressure of the pressurized gas raised in the scavenge tank, so there is no need for each pressurizing operation, and there is a risk of damage or wear in repeated operations. There is little fear that the mechanical characteristics of the spring will gradually change due to the impact force applied to the damper like a spring, and the initial height return function of the damper will be more excellent.

  As the best mode for carrying out the present invention, Examples 1 and 2 will be described below.

  A falling weight impact tester according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration explanatory view of the present embodiment, and FIG. 2 is a schematic cross-sectional explanatory view of a damper in the present embodiment. In FIG. 1 and FIG. 2, the same parts as those in FIG. 4 showing the conventional example are given the same reference numerals to simplify the description, and the parts different from the conventional example in this embodiment will be mainly described below. FIG. 1 is also used for the description of the second embodiment described later.

  As shown schematically in FIG. 1, the falling weight impact test machine 10 of the present embodiment replaces the cushioning material 9 shown in FIG. The damper 11 that restricts compression is positioned at the top of the damper position C below the contact position B of the falling weight 3 and the specimen 6 by a compression test range height b, and surrounds the specimen 6 with four groups. The falling weight 3 is provided so as to be received at the four corners, and the rest is configured similarly to the conventional example shown in FIG.

  An accelerating device 7 having a hydraulic drive system is provided on the frame 2 of the falling weight impact testing machine 10, and a falling weight holding device 8 capable of holding and separating the falling weight 3 at the tip of the hydraulic piston 7 a of the accelerating device 7. Is installed.

  In order to perform an impact test on the specimen 6 such as an automobile part, the falling weight (weight) 3 is lifted by an appropriate means (not shown), and the stopper 4 is placed at a predetermined height position A in the frame 2 of the falling weight impact tester 10. And is held by the falling weight holding device 8 at the tip of the hydraulic piston 7a of the acceleration device 7.

  Thereafter, the hydraulic drive system of the accelerating device 7, the falling weight holding device 8 and the stopper 4 are controlled by a control device (not shown) to pressurize the piston 7a downward with a predetermined pressure to push the falling weight 3 and open the stopper 4. (Dotted line in FIG. 1), the falling weight holding device 8 is released, the falling weight 3 is pushed downward at a predetermined initial speed, and the falling weight 3 is guided by a vertical slider (not shown) attached to the frame 2. The sample is dropped as indicated by a hollow outline and is made to collide with a specimen 6 placed at a predetermined position on the mounting table 5 immediately below it, and the state of the specimen 6 is verified.

  The falling weight 3 is accelerated and dropped by the external force and its own weight due to the pushing, and can be made to collide with the specimen 6, the falling height a can be shortened, and the collision speed can be adjusted and the pushing speed of the acceleration device 7 can be adjusted. Easy to do.

In addition, the damper 11 is installed with the top positioned at a damper position C (the initial height h ₀ of the damper 11) that is lower than the contact position B between the falling weight 3 and the specimen 6 by the compression test range height b. (For example, four bases are provided surrounding the specimen 6 and the falling weights 3 are received at the four corners.) The falling weight 3 collides with the specimen 6 and moves from the B position to the C position in the figure. After the compression of the compression test range height (compression height to be verified by applying compression to the specimen 6) b, the falling weight 3 collides with the top of the damper 11 and the damping action of the damper 11 is performed. The vehicle descends while receiving braking with reduced impact, and stops at a falling weight stop position D below the buffer distance c. The buffering distance c is set so that an appropriate buffering can be obtained with respect to the collision speed, the weight of the falling weight 3, the size of the specimen 6, and the like. Stroke.

  As shown in FIG. 2, the damper 11 has a hydraulic cylinder 12, a piston 13 that moves up and down in the hydraulic cylinder 12, a lower piston rod 14a, and an upper piston rod 14b. In this case, the lower end position of the piston 13 is defined by coming into contact with the inner surface of the lower end of the hydraulic cylinder 12, and the upper end of the upper piston rod 14b protrudes upward from the hydraulic cylinder 12 and is fitted with a cap 14c.

  The lower portion of the piston 13 in the hydraulic cylinder 12 forms a lower chamber 12a, and the upper portion forms an upper chamber 12b. The piston 13 abuts against the inner surface of the upper end of the hydraulic cylinder 12 when the piston 13 is most raised, and defines the ascending limit position of the piston 13, but an enlarged diameter portion 12 c is provided on the inner peripheral surface of the upper end of the hydraulic cylinder 12. Even when the piston 13 is in the upper limit position, the space of the upper chamber 12b is maintained. Note that the space of the upper chamber 12b at the upper limit of the piston 13 may be maintained by providing a small-diameter portion on the outer peripheral surface of the upper end of the piston 13 instead of or in addition to the enlarged diameter portion 12c.

  In the lower chamber 12a of the hydraulic cylinder 12, as a damper initial height return means, the piston 13 and the piston rods 14a, b can be moved to the upper limit position without the falling weight 3 being actuated, and can be positioned there. A spring 15 is provided in which an initial biasing force for biasing is set.

As will be described later, the spring 15 is compressed when the hydraulic cylinder 12 is actuated by receiving the falling weight 3 from which the damper 11 falls, and the piston 13 moves from the upper limit position to the lower limit position, and repulsion against the compression. strengthened by applying a force to the initial setting urging force, the piston 13, the piston rod 14a, b was raised to the upper limit position, it is returned to the damper initial height h _0.

  The springs are not limited to those provided in the lower chamber 12a as shown, but may be provided in the upper chamber 12b or outside as long as the piston rods 14a and 14b are returned to the upper limit position. Further, the spring 15 may be operated on the tension side.

Therefore, the top position of the cap 14c when the piston 13 is located at the upper limit is the damper position C (the initial height h ₀ of the damper 11), and the top position of the cap 14c when the piston 13 is at the lower limit position. This is the falling weight stop position D.

  Further, a lower chamber hydraulic oil opening 16a is provided in the lower chamber 12a of the hydraulic cylinder 12, and an upper chamber hydraulic oil aperture 16b is provided in the upper chamber 12b to form a hydraulic fluid communication circuit that communicates with each other via a communication pipe line 16c. A throttle valve 16d is interposed in the communication pipe line 16c as hydraulic oil throttle means.

  This hydraulic oil squeezing means limits the amount of movement of hydraulic oil m from the lower chamber 12a to the upper chamber 12b when the piston 13 is about to descend rapidly, and gives a damping action to the piston rods 14a, b. Yes, it may be provided in the hydraulic fluid communication circuit, and is not limited to the throttle valve 16d interposed in the communication conduit 16c, but may be one in which the lower chamber hydraulic fluid aperture 16a is formed to have a narrowed opening diameter that gives a throttle action. Good. The communication pipe 16c may be formed in the form of a double pipe that surrounds the hydraulic cylinder 12 and is closed at the upper and lower ends, instead of a general pipe. However, if the hydraulic fluid communication circuit is configured as in the first embodiment, the hydraulic cylinder 12 can be easily configured without requiring a special structure. Further, if the hydraulic oil throttle means is constituted by the throttle valve 16c as in the first embodiment, the hydraulic oil throttle means can be easily attached.

  The lower chamber 12a discharges the hydraulic oil m according to the inner diameter of the hydraulic cylinder 12 when the piston 13 descends. However, the upper chamber 12a always has the upper piston rod 14b and receives less hydraulic oil, and surplus hydraulic oil is generated. . The reverse occurs in the reverse process.

  That is, the volume changes of the lower chamber 12a and the upper chamber 12b with respect to the raising and lowering of the piston 13 and the piston rods 14a, b are different, and the volume change amount of the lower chamber 12a is large. Therefore, a hydraulic oil reservoir 17 is connected between the hydraulic oil throttle means and the upper chamber hydraulic oil opening 16b, and the total amount of hydraulic oil in the lower chamber 12a and the upper chamber 12b due to the movement of the piston 13 is calculated. Covers fluctuations.

In the falling weight impact test machine 10 of the present embodiment as described above, after the falling weight 3 falls and the specimen 6 is compressed to a predetermined compression test range height b, the white arrow in FIG. Thus, at the damper position C (initial height h ₀ of the damper 11), the falling weight 3 collides with the cap 14 c at the top of the upper piston rod 14 b of the damper 11. Therefore, the piston 13 rapidly descends as indicated by the white arrow, and the hydraulic oil m in the hydraulic cylinder 12 moves from the lower chamber 12a to the upper chamber 12b, the lower chamber hydraulic oil opening 16a, the communication conduit 16c, and the upper chamber hydraulic oil opening. Although it tries to move through the hydraulic fluid communication circuit comprising 16b, the flow rate is throttled by the throttle valve 16d as hydraulic fluid throttle means, and a damping action is given to the downward movement of the piston rods 14a, b. At this time, surplus that has moved to the upper chamber 12 b out of the hydraulic oil m discharged from the lower chamber 12 a is sent to the hydraulic oil reservoir 17.

  Therefore, the falling weight 3 receives the braking buffered by the damper 11, is rapidly braked avoiding an excessive impact at the buffering distance c, and finally stops at the falling weight stop position D.

  In the meantime, the spring 15 in the lower chamber 12a is compressed by the descending piston 13 as shown by a two-dot chain line in FIG. 2, but when the falling weight 3 is pulled up after the test, the spring 15 is set to the initial biasing force. Applying a repulsive force against compression, the piston 13 is pushed upward, and the top portion of the cap 14c of the upper piston rod 14b returns to the damper position C. At this time, of the hydraulic oil m that returns to the lower chamber 12a due to the rise of the piston 13, the amount that is insufficient for the hydraulic oil that moves from the upper chamber 12b moves from the hydraulic oil reservoir 17 to the lower chamber 12a.

For this reason, the damper 11 returns to the initial damper height h ₀ again without any special operation, so that it is ready for the next drop weight impact test. Installation is unnecessary, and the burden of test cost and work efficiency of the drop weight impact test can be remarkably reduced. In particular, in this embodiment, since the spring 15 is used as the damper initial height return means, the apparatus configuration can be simplified.

  Next, a falling weight impact tester according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 1 is a schematic configuration diagram of the present embodiment, and FIG. 3 is a cross-sectional diagram of a damper in the present embodiment. In FIG. 3, the same parts as those in FIG. 2 showing the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the present embodiment, parts different from the first embodiment are mainly described below.

  As shown schematically in FIG. 1, the falling weight impact test machine 20 of the present embodiment is different from the damper 11 shown in FIGS. 1 and 2 in that a damper 21 is provided. The configuration is the same as that of the first embodiment shown in FIGS.

  As shown in FIG. 1, in the falling weight impact test machine 20 of the present embodiment, an acceleration device 7 having a hydraulic drive system is provided on the frame 2 as in the first embodiment, and the hydraulic piston 7a of the acceleration device 7 is provided. A falling weight holding device 8 capable of holding and separating the falling weight 3 is attached to the tip of the falling weight.

  The impact test of the specimen 6 such as an automobile part is similarly performed using the falling weight 3.

The damper 21 of the present embodiment also has a damper 21 at the top at a damper position C (the initial height h ₀ of the damper 21) that is lower than the contact position B of the falling weight 3 and the specimen 6 by the compression test range height b. (For example, four bases are provided so as to surround the specimen 6 and the falling weights 3 are received at the four corners), and the falling weight 3 that has fallen as indicated by the white arrow in the figure is provided. After collision with the specimen 6 and compression of the compression test range height b from the B position to the C position in the figure, the falling weight 3 collides with the top of the damper 21 as indicated by the white arrow in FIG. Due to the damping action of the damper 21, the vehicle descends while receiving braking with reduced impact, and stops at a falling weight stop position D below the buffer distance c. The buffer distance c is set so as to obtain an appropriate buffer with respect to the collision speed, the weight of the falling weight 3, the size of the specimen 6, and the like. Stroke.

  As shown in FIG. 3, the damper 21 has a hydraulic cylinder 22, a piston 23 that moves up and down in the hydraulic cylinder 22, a lower piston rod 24a, and an upper piston rod 24b, and the lower end of the lower piston rod 24a is lowered most. Then, the lower end inner surface of the hydraulic cylinder 22 is brought into contact with the lower limit position of the piston 23, and the upper end of the upper piston rod 24b protrudes upward from the hydraulic cylinder 22 and is fitted with a cap 24c.

  The lower part of the piston 23 in the hydraulic cylinder 22 forms a lower chamber 22a, and the upper part forms an upper chamber 22b. The piston 23 comes into contact with the inner surface of the upper end of the hydraulic cylinder 22 when the piston 23 rises the most, and defines the ascending limit position of the piston 23. However, an enlarged diameter portion 22c is provided on the inner peripheral surface of the upper limit of the hydraulic cylinder 22, Even when the piston 23 is at the upper limit position, the space of the upper chamber 22b is maintained. Note that the space of the upper chamber 22b at the upper limit of the piston 23 may be maintained by providing a small-diameter portion on the outer peripheral surface of the upper end of the piston 23 instead of or in addition to the enlarged diameter portion 22c.

Accordingly, the top position of the cap 24c when the piston 23 is located at the upper limit is the damper position C (the initial height h ₀ of the damper 21), and the top position of the cap 24c when the piston 23 is at the lower limit position. This is the falling weight stop position D.

  The hydraulic cylinder 22 is attached with an outer cylinder 28 that forms a double-pipe structure that surrounds the side surface and closes the upper and lower ends, and an annular cross-sectional space 26 c is formed between the outer peripheral surface of the hydraulic cylinder 22 and the outer cylinder 28. ing. On the side of the hydraulic cylinder 22, a lower chamber hydraulic oil opening 26a that communicates the lower chamber 22a and the annular sectional space 26c is provided, and an upper chamber hydraulic oil opening 26b that communicates the upper chamber 22b and the annular sectional space 26c. .

  Further, the lower chamber hydraulic oil opening 26a restricts the amount of movement of the hydraulic oil m from the lower chamber 22a to the annular cross-section space 26c when the piston 23 is going to descend rapidly as indicated by the white arrow. The opening diameter is set so as to give a damping action to 24a and b. Moreover, it is preferable that the number of lower chamber hydraulic oil openings 26a that are provided at a plurality of locations and communicate with each other as the piston 23 descends is reduced by the piston 23 to increase the damping action.

  Accordingly, the lower chamber 22a of the hydraulic cylinder 22 communicates with a hydraulic fluid communication circuit formed by the lower chamber hydraulic fluid opening 26a, the annular sectional space 26c, and the upper chamber hydraulic fluid opening 26b, and the lower chamber hydraulic fluid opening 26a operates. Functions as oil squeezing means.

  The hydraulic oil throttle means limits the amount of movement of the hydraulic oil m from the lower chamber 22a to the annular cross-sectional space 26c when the piston 23 is going to drop rapidly, and gives a damping action to the piston rods 24a, b. The hydraulic fluid communication circuit may be provided, and instead of the annular sectional space 26c having the double pipe structure, the communication fluid passage 16c as shown in the first embodiment is provided to provide the lower chamber hydraulic oil opening 26a. When the upper chamber hydraulic oil opening 26b is communicated, an appropriate throttle valve 16d may be interposed in the communication pipe line 16c as hydraulic oil throttle means.

  Further, as described in the first embodiment, the lower chamber 22a discharges the hydraulic oil m according to the inner diameter of the hydraulic cylinder 22 when the piston 23 descends, but the upper chamber 22b always has the upper piston rod 24b and the hydraulic oil m to be received is Less surplus hydraulic oil m is produced. The reverse occurs in the reverse process.

  That is, the volume changes of the lower chamber 22a and the upper chamber 22b with respect to the elevation of the piston 23 and the piston rods 24a, b are different, and the volume change amount of the lower chamber 22a is large. Therefore, in the first embodiment, in order to cover the change in the total amount of hydraulic oil in the lower chamber 12a and the upper chamber 12b due to the movement of the piston 13, a hydraulic oil reservoir is provided between the hydraulic oil throttle means and the upper chamber hydraulic oil opening 16b. In this embodiment, the scavenge tank 30 is communicated with an annular sectional space 26c that connects between the lower chamber hydraulic oil opening 26a and the upper chamber hydraulic oil opening 26b as hydraulic oil throttle means. Provided.

  The scavenge tank 30 functions as a damper initial height return means, and is connected to the annular cross-sectional space 26c through a large-diameter communication portion 30a having a small flow resistance, and moves to the inside of the hydraulic tank via the communication portion 30a. This is a closed tank filled with the corresponding hydraulic oil m and filled with a pressurized gas n (air or rare gas) having a predetermined pressure (for example, 5 atm) at the top of the liquid level of the hydraulic oil m.

  The pressure of the pressurized gas acts on the hydraulic cylinder 22 via the hydraulic oil m in the scavenge tank 30, but the lower chamber 22a side of the piston 23 is the pressure receiving surface of the entire hydraulic cylinder 22 and the upper chamber 22b side. Since the surface excluding the upper piston rod 24b is the pressure receiving surface, the piston 23 is urged upward by the pressure difference. Therefore, the pressure of the pressurized gas is set to a pressure at which the piston 23 and the piston rods 24a, b are moved to their upper limit positions in a state where the falling weight 3 does not act.

  Further, the scavenge tank 30 receives the falling weight 3 from which the damper 21 is dropped and stops, and when the hydraulic cylinder 22 is operated and its piston 23 is lowered from the upper limit position to the lower limit position, the lower chamber 22a is changed to the upper chamber 22b. The surplus amount of hydraulic oil m moving to the scavenge tank 30 is received by the movement of the hydraulic oil m from the hydraulic cylinder 22 to the scavenge tank 30 (from position E in FIG. The gas region 31 of the pressurized pressurized gas n is narrowed by the rise to F), and as a result, the pressure of the pressurized gas n is increased.

In the falling weight impact testing machine 20 of the present embodiment as described above, after the falling weight 3 falls and the specimen 6 is compressed to a predetermined compression test range height b, the white arrow in FIG. Thus, at the damper position C (initial height h ₀ of the damper 21), the falling weight 3 collides with the cap 24 c at the top of the upper piston rod 24 b of the damper 21.

  Therefore, the piston 23 suddenly descends, and the hydraulic oil m in the hydraulic cylinder 22 communicates from the lower chamber 22a to the upper chamber 22b through the hydraulic fluid communication comprising the lower chamber hydraulic oil opening 26a, the annular cross-sectional space 26c, and the upper chamber hydraulic oil opening 26b. While trying to move through the circuit, the flow rate is throttled by the lower chamber hydraulic oil opening 26a as the hydraulic oil throttle means, and a damping action is given to the downward movement of the piston rods 24a, b.

  Therefore, the falling weight 3 receives the braking buffered by the damper 21, is rapidly braked at the buffering distance c while avoiding an excessive impact, and finally stops at the falling weight stop position D.

  At this time, surplus that has moved to the upper chamber 22b out of the hydraulic oil m discharged from the lower chamber 22a is sent to the scavenge tank 30, and the hydraulic oil surface in the scavenge tank 30 has an initial oil level as shown in FIG. From the position E to the maximum oil level position F, the height e is increased, and the upper gas region 31 is narrowed accordingly, and the pressure of the pressurized gas n is increased (for example, 8 to 10 at the initial pressure of 5 atm). To atmospheric pressure).

  After the test, when the falling weight 3 is pulled up, the hydraulic oil m in the scavenge tank 30 passes through the communication portion 30a and the annular sectional space 26c by the pressure of the pressurized pressurized gas n, and the lower chamber hydraulic oil opening 26a. The hydraulic chamber 22 is pushed back to the lower chamber 22a and from the upper chamber hydraulic oil opening 26b to the upper chamber 22b. The lower chamber 22a has the entire diameter of the hydraulic cylinder 22 as a pressure receiving surface, and the upper chamber 22b has an upper piston. Since the surface excluding the rod 24b is the pressure receiving surface, the piston 23 rises due to the pressure difference, stops at the upper limit position of the hydraulic cylinder 22, and returns so that the top of the cap 24c of the upper piston rod 24b reaches the damper position C.

For this reason, the damper 21 returns to the initial damper height h ₀ again without any special operation, so that it is ready for the next drop weight impact test. Installation is unnecessary, and the burden of test cost and work efficiency of the drop weight impact test can be remarkably reduced.

In particular, in this embodiment, the operation of returning the position of the damper 21 to the initial state is performed by the pressure of the pressurized gas n increased in pressure in the scavenge tank 30, so that each pressurizing operation is unnecessary, and in repeated operations. In the case of a mechanism in which the damper 11 is returned to the initial state by the spring 15 as in the case of the first embodiment, the mechanical characteristics of the spring 15 are gradually increased depending on the impact force that the damper 11 receives. There was a concern that the piston rods 14a, b could not be returned to the initial height h ₀ (position C) and the spring 15 had to be replaced. However, in the case of Example 2, there was no such fear. The function of returning the initial state of the damper 21 becomes more excellent.

  Further, since the scavenge tank 30 is connected to the annular cross-sectional space 26c through the large-diameter communication portion 30a having a small flow resistance, there is substantially no pressure difference at the connection portion, and during the damping operation and when the initial state is restored. There is no hindrance to the movement of the hydraulic oil m.

  Since the lower chamber hydraulic oil opening 26a is used as the hydraulic oil throttle means, the high pressure generated in the lower chamber 22a during the damping operation does not act on the outside of the lower chamber hydraulic oil opening 26a. The mechanical specifications of the falling weight impact tester such as a circuit can be reduced. In the case of the present embodiment, the annular cross-sectional space 26c and the scavenge tank 30 are from the initial gas pressure to the pressure increase due to the hydraulic oil inflow at the time of damping (for example, from about 5 atm to about 8 to 10 atm in the above example). Therefore, the mechanical shock can be reduced and the mechanical specifications of the falling weight impact tester can be reduced.

  In the second embodiment, the hydraulic oil communication circuit does not have the double pipe structure formed by the outer cylinder 28 as described above, and the communication pipe 16c is provided as in the first embodiment, so that an appropriate throttle is provided as the hydraulic oil throttle means. When the valve 16d is interposed in the communication pipe 16c, the scavenge tank 30 may be connected to the communication pipe 16c between the throttle valve 16d and the upper chamber hydraulic oil opening 26b. However, if the double pipe structure with the outer cylinder 28 is used as the hydraulic fluid communication circuit as in the second embodiment, the hydraulic fluid communication circuit can be integrated into a compact form and can be connected to the scavenge tank 30. It becomes easy to connect with the large-diameter communication portion 30a with little road resistance.

  The present invention has been described with reference to the illustrated embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications may be made to the specific structure and configuration within the scope of the present invention. Nor.

  For example, although both the above embodiments have been described with respect to an example of a falling weight impact tester that provides the acceleration device 7 and pushes out the falling weight 3, the present invention can also be applied to a falling weight impact test device that does not include the acceleration device 7. Needless to say, it can be used in the same manner.

It is typical structure explanatory drawing of the falling weight impact tester based on Example 1 and Example 2 of this invention. It is typical sectional explanatory drawing of the damper in Example 1. FIG. FIG. 6 is a cross-sectional explanatory view of a damper in Example 2. It is typical structure explanatory drawing of the conventional falling weight impact tester.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drop weight impact test machine 2 Frame 3 Drop weight 4 Stopper 5 Mounting stand 6 Specimen 7 Acceleration device 7a Hydraulic piston 8 Drop weight holding device 9 Buffer material 10 Drop weight impact test machine 11 Damper 12 Hydraulic cylinder 12a Lower chamber 12b Upper chamber 12c Expanded part 13 Piston 14a Lower piston rod 14b Upper piston rod 14c Cap 15 Spring 16a Lower chamber hydraulic oil opening 16b Upper chamber hydraulic oil opening 16c Communication pipe line 16d Throttle valve 17 Hydraulic oil reservoir 20 Drop weight impact tester 21 Damper 22 Hydraulic cylinder 22a Lower chamber 22b Upper chamber 22c Expanded portion 23 Piston 24a Lower piston rod 24b Upper piston rod 24c Cap 26a Lower chamber working oil opening 26b Upper chamber working oil opening 26c Annular section space 28 Outer cylinder 30 Scavenge tank 30a Communication portion 31 Gas region

Claims (7)

  In a drop weight impact tester for performing an impact test of a specimen with a drop weight, the drop rod is provided with a damper that stops the falling weight halfway to limit the compression of the specimen, and the damper is a piston rod protruding upward A hydraulic cylinder filled with hydraulic oil in an upper chamber and a lower chamber on the upper side of the piston, and a hydraulic fluid communication circuit in which the hydraulic fluid is movably communicated between the lower chamber and the upper chamber, Hydraulic oil throttle means for limiting the amount of hydraulic oil movement in the hydraulic oil communication circuit, and damper initial height return means for biasing the piston rod to be positioned at its upper limit position when the falling weight is not applied; A falling weight impact tester characterized by comprising:   2. The falling weight impact tester according to claim 1, wherein the hydraulic fluid communication circuit includes a lower chamber hydraulic fluid opening that opens from the lower chamber to the outside of the hydraulic cylinder, and an opening from the upper chamber to the outside of the hydraulic cylinder. A falling weight impact tester comprising: an upper chamber hydraulic oil opening, and a communication pipe line communicating the lower chamber hydraulic oil opening and the upper chamber hydraulic oil opening.   2. The falling weight impact tester according to claim 1, wherein the hydraulic fluid communication circuit includes an outer cylinder that forms a double pipe structure that surrounds a side surface of the hydraulic cylinder and has upper and lower ends closed, and an outer peripheral surface of the hydraulic cylinder. An annular sectional space formed therebetween, a lower chamber hydraulic oil opening that opens from the lower chamber to the annular sectional space, and an upper chamber hydraulic oil opening that opens from the upper chamber to the annular sectional space. A falling weight impact tester characterized by that.   3. The falling weight impact testing machine according to claim 2, wherein the hydraulic oil throttle means is constituted by a throttle valve interposed in the communication pipe.   4. The falling weight impact testing machine according to claim 2, wherein the hydraulic oil throttle means is constituted by the lower chamber working oil opening.   6. The drop weight impact tester according to claim 1, wherein the damper initial height return means applies a biasing force to position the piston rod at an upper limit position in a state where the drop weight does not act. A drop weight impact tester comprising: a spring configured to strengthen the biasing force by lowering the piston rod by the action of a drop weight.   6. The falling weight impact tester according to claim 1, wherein the damper initial height return means communicates with the hydraulic fluid communication circuit between the hydraulic fluid throttle means and the upper chamber. The hydraulic cylinder includes a scavenge tank that encloses hydraulic oil and pressurized gas. The hydraulic cylinder has a volume change in the lower chamber larger than a volume change in the upper chamber with respect to the lifting and lowering of the piston rod, and an initial pressure of the pressurized gas. Is a pressure that acts on the hydraulic cylinder via the hydraulic oil in a state where the falling weight does not act to position the piston rod at its upper limit position, and the scavenge tank is moved by the lowering of the piston rod due to the falling weight. The gas region of the pressurized gas is configured to be narrowed by hydraulic oil that moves from a hydraulic cylinder to a scavenge tank. Weight impact test machine.

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