Test equipment

Abstract

The present invention provides a test apparatus that can measure the characteristics of shock absorbers while improving the reproducibility of actual driving conditions. [Solution] The test apparatus 1 comprises a linear motor vibrator 3, a relay means 4 connected to the output section 34 of the linear motor vibrator 3 and the connection section 101 of the shock absorber 100 to transmit vibrations, and a holding means 5 that holds the upper end portion 102 of the shock absorber 100. Since the holding means 5 has not only a displacement mechanism 51 but also a three-axis load meter 52 and a load control load cell, it is possible to measure the load applied to the shock absorber 100 in the X and Y directions while measuring the load in the Z direction (i.e., the characteristics of the shock absorber 100). That is, the upper end portion 102 of the shock absorber 100 can be positioned in the XY plane so that a desired load is applied to the shock absorber 100 in the XY plane, thereby improving the reproducibility of actual driving conditions.

Description

Technical Field

[0001] The present invention relates to a test apparatus for measuring the characteristics of a shock absorber by applying vibrations thereto.

Background Art

[0002] Conventionally, a test apparatus has been proposed for testing the performance and durability of a suspension by applying vibrations with a vibrator while loading a load on the suspension (see, for example, Patent Document 1). In the test apparatus described in Patent Document 1, the actual running conditions are reproduced by making it possible to adjust the offset amount in the lateral direction of a connecting pin, which is the load application point to the shock absorber.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when adjusting the offset amount in the lateral direction as in the test apparatus described in Patent Document 1, even with the same offset amount, the actual influence on the shock absorber varies depending on the dimensions, rigidity, etc. of the shock absorber itself. Therefore, simply adjusting the offset amount in the lateral direction is insufficient to reproduce the actual running conditions, and an improvement in the degree of reproduction has been desired.

[0005] An object of the present invention is to provide a test apparatus capable of improving the degree of reproduction of actual running conditions and measuring the characteristics of a shock absorber.

Means for Solving the Problems

[0006] The present invention relates to a test apparatus for measuring the characteristics of a shock absorber by applying vibration in the expansion and contraction direction, comprising: an excitation means for generating vibration; a relay means connected to the output of the excitation means and one end of the shock absorber for transmitting vibration; and a holding means for holding the other end of the shock absorber, wherein the holding means comprises: a displacement mechanism for displacing the other end in at least one direction in a plane intersecting the expansion and contraction direction; and a load measuring unit for measuring the load applied to the other end, wherein the load measuring unit measures the load in the expansion and contraction direction and the load in at least two directions in a plane intersecting the expansion and contraction direction.

[0007] As described above, the present invention includes not only a displacement mechanism but also a load measuring unit, allowing for the measurement of the load applied to the shock absorber in at least two directions in a plane intersecting the expansion and contraction directions, while simultaneously measuring the load in the expansion and contraction direction (i.e., the characteristics of the shock absorber). That is, the other end of the shock absorber can be positioned within this plane so that a desired load is applied to the shock absorber within this plane, thereby improving the reproducibility of actual driving conditions. Note that "desired load" includes a load of 0, meaning that the other end of the shock absorber can also be positioned so that no load is applied to the shock absorber.

[0008] In this case, the test apparatus of the present invention preferably has a relay means comprising a relay body portion extending along a plane intersecting the extension direction and a plurality of rods connected to the relay body portion, wherein the outer circumferential surface of the rods has a plurality of planar portions extending along a plane including the vibration direction, and the planar portions are guided by guide portions that are pivotally supported so as to be rotatable around a rotation axis extending in a direction perpendicular to the vibration direction. With such a configuration, when the other end of the shock absorber is displaced by the displacement mechanism, it is possible to suppress the shock absorber from being displaced in such a way that it rotates (twists) around an axis along the extension direction.

[0009] Furthermore, in the test apparatus of the present invention, the relay means preferably includes a relay body portion extending along a plane intersecting the extension direction, and a plurality of rods connected to the relay body portion and extending along the extension direction and guided along the extension direction, wherein the plurality of rods preferably include a pair of rods, and the output portion is located between the pair of rods in a direction intersecting the extension direction, or includes three or more rods arranged to surround the output portion. With such a configuration, when the other end of the shock absorber is displaced by the displacement mechanism, the displacement of one end of the shock absorber can be suppressed by the plurality of rods, and vibration can be applied stably.

[0010] Furthermore, in the test apparatus of the present invention, it is preferable that the load measuring section includes two measuring sections with different upper measurement limits in the expansion and contraction direction. With such a configuration, it is possible to select the measuring section to use according to the load applied in a direction intersecting the expansion and contraction direction, thereby improving the degree of freedom in setting the load in the direction intersecting the expansion and contraction direction and improving measurement accuracy. A measuring section with a low upper measurement limit has high resolution, but may not be able to withstand large loads in the direction intersecting the expansion and contraction direction. In such cases, under conditions where the load in the direction intersecting the expansion and contraction direction is relatively small, measurement accuracy can be ensured by using a measuring section with a low upper measurement limit, and under conditions where the load in the direction intersecting the expansion and contraction direction is relatively large, a measuring section with a high upper measurement limit can be used. [Effects of the Invention]

[0011] According to the test apparatus of the present invention, it is possible to measure the characteristics of a shock absorber while improving the reproducibility of actual driving conditions. [Brief explanation of the drawing]

[0012] [Figure 1] This is a front view showing a test apparatus according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view showing the vibration means of the test apparatus. [Figure 3] A cross-sectional view showing the relay means of the test apparatus. [Figure 4] A cross-sectional view showing the relay means of the test apparatus. [Figure 5] This is a cross-sectional view showing the state in which the braking means of the test device has stopped moving. [Figure 6] This is a cross-sectional view showing the state in which the brake means of the test device has been released. [Figure 7] This is a perspective view showing the holding means of the test apparatus. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described with reference to the drawings. As shown in Figure 1, the test apparatus 1 of this embodiment uses a shock absorber 100 as a test specimen, applies vibration along the longitudinal direction (extension direction) of the shock absorber 100, and measures various characteristics of the shock absorber 100 during vibration.

[0014] Examples of characteristics of the shock absorber 100 to be measured include the extension and retraction speed of the shock absorber 100, the piston load, and the displacement in the direction of vibration. Furthermore, positional and temporal characteristics (displacement, velocity, acceleration) can be converted to other characteristics by measuring the time change of one characteristic, and the characteristics (physical quantities) to be directly measured can be selected as appropriate. That is, an appropriate type of sensor can be used depending on the characteristics of the shock absorber 100 and the test conditions. In this embodiment, a linear encoder 35 is used as described later, but other sensors may be used instead or in addition. Also, the test specimen may be the shock absorber 100 alone, or it may be the shock absorber 100 combined with other components such as a spring.

[0015] The test apparatus 1 comprises a main frame 2, a linear motor exciter 3 as an electrically operated vibration excitation means, a relay means 4, a holding means 5, a braking means 6, and a control unit (not shown). Hereafter, the horizontal plane will be referred to as the XY plane and the vertical direction as the Z direction, and the up and down directions in the Z direction will be simply referred to as up and down.

[0016] The main body frame 2 includes a lower frame 21, an upper frame 22, and a lifting cylinder 23 that connects the lower frame 21 and the upper frame 22.

[0017] The lower frame 21 is placed on the floor surface of a test site or the like, and a linear motor vibrator 3 is provided. It also has a support base 211 above the linear motor vibrator 3. A plurality of guide parts 212 for guiding a rod 42 described later are provided on the support base 211.

[0018] The upper frame 22 is arranged at a predetermined height with respect to the lower frame 21, and the holding means 5 is suspended.

[0019] The lifting cylinder 23 is configured such that the height of the upper frame 22 with respect to the lower frame 21 can be adjusted by extending and contracting. That is, the lifting cylinder 23 can be appropriately extended and contracted according to the length of the shock absorber 100.

[0020] As shown in FIG. 2, the linear motor vibrator 3 includes a case 31, a motor coil 32 fixed to the inner surface of the case 31, an output part 34 that is arranged to be linearly movable inside the motor coil 32 and protrudes outside the case 31, and a magnet 33 fixed to the output part 34. The linear motor vibrator 3 is arranged such that the vibration direction is in the Z direction. The output part 34 is formed in a flat plate shape extending along the YZ plane and penetrates the support base 211 in the Z direction.

[0021] The linear motor vibrator 3 is provided with a linear encoder 35 which is a displacement sensor for detecting the position of the output part 34. By measuring the time change of the displacement of the output part 34, the speed and acceleration of the output part 34 can be calculated. Due to the connection structure as described later, the output part 34 vibrates integrally with the cylinder part 100A of the shock absorber 100, so the displacement, speed, and acceleration of the cylinder part 100A can be measured by the linear encoder 35.

[0022] As shown in Figure 3, the relay means 4 includes a support base 41 as the relay unit body and four metal rods 42. The support base 41 is formed as a rectangular plate shape extending along the XY plane, and its upper surface 411 also extends along the XY plane. The rods 42 are guide rods, arranged near the four corners of the support base 41 and extending along the Z direction. That is, two pairs of rods are formed by two rods 42 aligned in the X direction, and two pairs of rods are formed by two rods 42 aligned in the Y direction. Each rod 42 penetrates the support base 211 in the Z direction and is inserted into the guide portion 212. As shown in Figures 4 to 6, the outer circumferential surface 42A of the rod 42 has four planar portions 421 and four connecting surfaces 422. Two of the planar portions 421 extend along the YZ plane, and the other two planar portions 421 extend along the ZX plane. The connecting surface 422 is a curved surface that connects the two planar sections 421, and is arc-shaped when viewed from the Z direction.

[0023] The guide section 212 is a linear bearing having multiple guide rollers 213, and is provided at two locations, above and below the support base 211, for each rod 42. A pair of guide rollers 213 are pivotally supported with the X direction, which is perpendicular to the vibration direction Z, as both the axial direction and width direction, and sandwich the rod 42 from the Y direction. Another pair of guide rollers 213 are pivotally supported with the Y direction, which is perpendicular to the vibration direction Z, as both the axial direction and width direction, and sandwich the rod 42 from the X direction. In other words, the guide rollers 213 are rollers pivotally supported so as to be rotatable around a rotation axis extending in a direction perpendicular to the vibration direction, and do not move in the Z direction, which is the vibration direction, when rotating. The outer circumferential surface of the guide roller 213 has a predetermined width in the axial direction, and its center is convex toward the rod 42 side (it is curved in the cross-section as shown in Figure 4), making it a so-called spherical type roller follower (this convex shape is not shown in Figure 4 because the amount of protrusion is small). As a result, the guide roller 213 makes point-like contact with the flat portion 421 of the rod 42.

[0024] As described above, the flat portion 421 and the guide roller 213 come into contact, and the guide roller 213 is rotatable, so the rod 42 is guided along the Z direction, and consequently the support base 41 also moves along the Z direction.

[0025] The support base 41 is connected to the shock absorber 100 via a connecting jig 200. The jig 200 is shaped to match the shape of the shock absorber 100. In this embodiment, since the shock absorber 100 has a connecting portion 101 on the side of the cylinder portion 100A, the jig 200 is formed in an L-shape, having a portion fixed to the connecting portion 101 and a portion fixed to the upper surface 411 of the support base 41. The upper surface 411 has a plurality of recesses, and the jig 200 can be fixed by placing nuts in these recesses and fastening them with bolts. The tip of the output portion 34 of the linear motor vibrator 3 is fixed to the lower surface of the support base 41. In this way, the relay means 4 transmits vibrations by connecting the output portion 34 of the linear motor vibrator 3 to the connecting portion 101, which is one end of the shock absorber 100.

[0026] The position on the support base 41 to which the output unit 34 of the linear motor exciter 3 is connected is located between two rods 42 aligned in the Y direction on the left side in the X direction in Figure 1, and two rods 42 aligned in the Y direction on the right side in the X direction, and is particularly located in the center. Thus, in the X direction, the output unit 34 of the linear motor exciter 3 is located between each of the two pairs of rods.

[0027] As shown in Figure 7, the holding means 5 includes a displacement mechanism 51, a three-axis load cell 52, a support block 53, and a load control load cell (not shown).

[0028] The displacement mechanism 51 is fixed so as to be suspended from the upper frame 22 and includes a first displacement section 511 that causes displacement in the X direction, a second displacement section 512 that causes displacement in the Y direction, and a fixed block 513 fixed to the upper frame 22. Two rows of groove-shaped rail sections 513A extending along the X direction are formed on the lower surface of the fixed block 513, and the two rows of rail sections 513A are aligned in the Y direction. The first displacement section 511 includes a first movable block 511A provided on the lower side of the fixed block 513, a manual handle 511B for moving the first movable block 511A, and a manual lock lever 511C for fixing the position of the first movable block 511A. The first movable block 511A has a protrusion that projects upward and engages with each of the two rows of rail sections 513A, thereby allowing it to move relative to the fixed block 513 in the X direction. The first displacement section 511 is equipped with a screw feed mechanism, which converts the rotational motion of the manual handle 511B, centered on a rotation axis along the Y direction, into linear motion along the X direction. Specifically, when the tester operates the manual lock lever 511C to unlock and simultaneously operates the manual handle 511B, the first movable block 511A moves in the X direction, and when the manual lock lever 511C is operated to lock it, the first movable block 511A becomes immobile. Furthermore, two rows of groove-shaped rail sections 511D extending along the Y direction are formed on the lower surface of the first movable block 511A, and the two rows of rail sections 511D are aligned in the X direction.

[0029] The second displacement section 512 includes a second movable block 512A provided below the first movable block 511A, a manual handle 512B for moving the second movable block 512A, and a manual lock lever 512C for fixing the position of the second movable block 512A. The second movable block 512A has a protrusion that projects upward and engages with each of the two rows of rail sections 511D, thereby allowing it to move relative to the first movable block 511A in the Y direction. The second displacement section 512 is provided with a screw feed mechanism, so that the rotational motion of the manual handle 512B around a rotation axis along the Y direction is converted into linear motion along the Y direction. When the tester operates the manual lock lever 512C to unlock and operates the manual handle 512B, the second movable block 512A moves in the Y direction, and when the tester operates the manual lock lever 512C to lock it, the second movable block 512A becomes immobile.

[0030] The three-axis load cell 52 is installed below the second movable block 512A and above the support block 53 of the second displacement section 512. That is, it is positioned so as to be sandwiched in the Z direction by the second movable block 512A and the support block 53, and measures the loads in the X, Y, and Z directions that occur between the second movable block 512A and the support block 53. The measurement method of the three-axis load cell 52 is not particularly limited and may be a strain gauge type or a piezoelectric type. The upper measurement limit of the three-axis load cell 52 is, for example, 10 to 30 kN in each direction.

[0031] The support block 53 is formed in a flat plate shape extending along the XY plane and is connected to the shock absorber 100 via a connecting jig 300. Specifically, the lower surface of the support block 53 has a plurality of recesses, and the jig 300 can be fixed by placing nuts in these recesses and fastening them with bolts. The upper part of the jig 300, which is rectangular in shape when viewed from the Y direction, is fixed to the support block 53, and the lower part of the jig 300 is fixed to the upper end 102 of the shaft portion 100B of the shock absorber 100 (the other end of the shock absorber 100). At this time, a load control load cell (not shown) is provided between the support block 53 and the jig 300.

[0032] The load-controlled load cell measures the load in the Z direction, and its upper measurement limit is, for example, several kN (e.g., 1 to 3 kN), which is different from the upper measurement limit of the three-axis load cell 52. The load-controlled load cell, the three-axis load cell 52 as described above, and the three-axis load cell 52 and the load-controlled load cell as described above constitute the load measurement unit, and each of these acts as a measurement unit. When the lateral load applied by the displacement mechanism 51 is relatively small, it is preferable to measure the load in the Z direction using both the three-axis load cell 52 and the load-controlled load cell (or the load-controlled load cell only). When the lateral load is relatively large, it is preferable to remove the load-controlled load cell and measure the load in the Z direction using only the three-axis load cell 52.

[0033] As described above, the connecting portion 101, which is one end of the shock absorber 100, is fixed to the relay means 4 via the jig 200, and the relay means 4 is immovable in the XY plane relative to the lower frame 21. Therefore, the connecting portion 101 is immovable in the XY plane relative to the lower frame 21. Furthermore, the upper end portion 102, which is the other end of the shock absorber 100, is fixed to the holding means 5 via the jig 300, and the holding means 5 is fixed to the upper frame 22. Therefore, when the displacement mechanism 51 is locked, the upper end portion 102 is immovable in the XY plane relative to the upper frame 22. Since the lower frame 21 and the upper frame 22 are immovable relative to each other in the XY plane, the connecting portion 101 and the upper end portion 102 are immovable relative to each other in the XY plane. Therefore, the three-axis load cell 52 measures the load in the XY plane (X direction and Y direction) as a lateral load generated between the connection part 101 and the upper end part 102 of the shock absorber 100, and also measures the load in the Z direction generated between the connection part 101 and the upper end part 102 of the shock absorber 100. The load control load cell measures the load in the Z direction generated between the connection part 101 and the upper end part 102 of the shock absorber 100.

[0034] Furthermore, in the Z direction, only the load due to the vibration of the linear motor exciter 3 is applied between the connection part 101 and the upper end part 102, and this load is measured by the three-axis load cell 52.

[0035] Furthermore, the X and Y direction measurements obtained by the 3-axis load cell 52 are displayed on a display unit, such as a screen, so that the tester can see them. That is, the tester can adjust the displacement in the X and Y directions by operating the manual handles 511B and 512B based on the displayed measurements. In the case of test conditions where no lateral load is applied, the displacement mechanism 51 sets its origin to a position where no load is applied to the shock absorber 100 (displacement amounts in the X and Y directions are 0). However, errors may occur due to manufacturing errors or repeated measurements, and even if the displacement mechanism 51 is positioned at the origin, some load may be measured in the XY plane. Even in the test conditions where no lateral load is applied, the displacement mechanism 51 is used to adjust the displacement in the X and Y directions so that the lateral load is 0.

[0036] As shown in Figures 5 and 6, the braking means 6 includes a pair of clamping units 61A and 61B provided on both sides of the rod 42 in a direction along the XY plane (the X direction in the example shown in Figures 5 and 6), and a sensor 62. The braking means stops the movement of the rod 42 in the Z direction by holding the connecting surface 422 of the outer circumferential surface 42A of the rod 42, which is the object to be braked. Each of the clamping units 61A and 61B includes a clamping portion 63 for contacting and clamping the rod 42, a shaft portion 64 connected to the clamping portion 63 and extending away from the rod 42, a compression spring 65 as a biasing means for applying a biasing force to the clamping portion 63, and a hydraulic drive unit 66 for applying a force to the shaft portion 64 in the opposite direction to that of the compression spring 65.

[0037] The pair of clamping portions 63 are metal parts that clamp the rod 42 by approaching each other in the X direction. On the side facing the rod 42, the clamping portions 63 are formed in a concave shape with a pair of tapered surfaces 631 inclined in the X direction and a bottom surface 632 formed between the pair of tapered surfaces 631. The tapered surfaces 631 abut against the connection surface 422 of the rod 42. At this time, the connection surface 422 is curved, while the tapered surfaces 631 are flat. These may also be in linear contact in a straight line extending in the Z direction. Alternatively, the outer circumferential surface 42A of the rod 42 and the clamping portions 63 may be made of metals with different hardnesses, and the softer metal may deform slightly to achieve a predetermined contact width. Furthermore, as shown in Figure 5, when the connection surface 422 and the tapered surfaces 631 come into contact, the flat portion 421 of the rod 42 is separated from the bottom surface 632, so that no braking force is applied to the flat portion 421.

[0038] The shaft portion 64 is inserted through the compression spring 65. The clamping portion 63 connected to one end of the shaft portion 64 has a larger diameter than the shaft portion 64, and the case 661 of the hydraulic drive unit 66 connected to the other end of the shaft portion 64 has a larger diameter than the shaft portion 64. As a result, the compression spring 65 is positioned between the clamping portion 63 and the hydraulic drive unit 66 and is compressible.

[0039] The end of the shaft portion 64 opposite to the clamping portion 63 is a flange portion 641, which divides the space inside the case 661 in the X direction. By introducing hydraulic fluid into the two divided spaces inside the case 661, a hydraulic driving force is applied to the flange portion 641 according to the pressure difference between these spaces.

[0040] Sensor 62 is a proximity sensor that detects changes in induced current caused by the approach of a metal member. It is attached to one of a pair of clamping parts 63 and detects the approach of a metal member 67 attached to the other clamping part 63 (it detects whether the metal member 67 is located within a predetermined range). In other words, sensor 62 detects the distance between the pair of clamping parts 63. Brake means 6 is connected to the control unit of the test device 1 in a way that allows communication (either wired or wireless communication), and when the distance between sensor 62 and the metal member 67 exceeds a predetermined value, it transmits a release completion signal to the control unit. In other words, the release completion signal is a signal indicating that the distance between the pair of clamping parts 63 has exceeded a predetermined value.

[0041] This braking means 6 holds the rod 42 and stops its movement when the hydraulic drive unit 66 is not operating (when the pressure on both sides of the flange portion 641 is approximately equal). That is, when the clamping portion 63 is in contact with the rod 42, the compression spring 65 is compressed by a predetermined amount from its natural state (undeformed state), generating a biasing force in the direction of holding the rod 42 (moving towards the rod 42). In this state, when hydraulic fluid is introduced into the space on the rod 42 side of the flange portion 641 within the case 661 to increase the pressure, a driving force opposite to the biasing force of the compression spring 65 is generated, compressing the compression spring 65 and causing the shaft portion 64 and clamping portion 63 to move away from the rod 42, thus releasing the brake. That is, the hydraulic drive unit 66 functions as a means of generating a release force that generates a release force against the biasing force of the compression spring 65. When the pair of clamping portions 63 have separated sufficiently, a release completion signal is transmitted from the sensor 62 to the control unit.

[0042] By reducing the pressure in the space on the rod 42 side of the flange portion 641 within the case 661, the biasing force of the compression spring 65 causes the shaft portion 64 and the clamping portion 63 to move closer to the rod 42, and the movement of the rod 42 is stopped again.

[0043] Here, an example of the procedure for testing the shock absorber 100 in the test apparatus 1 will be described. First, the tester positions the displacement mechanism 51 at the origin and connects the shock absorber 100 to the support base 41 via the jig 200 and to the support block 53 via the jig 300. Next, the tester unlocks the manual lock levers 511C and 512C and adjusts the displacement in the X and Y directions by operating the manual handles 511B and 512B. At this time, the displacement in the X and Y directions may be adjusted alternately, or the displacement in one direction may be determined first and then the displacement in the other direction may be determined. Once the adjustment of the displacement is complete, the operator locks the manual lock levers 511C and 512C.

[0044] When adjusting the displacement of the displacement mechanism 51 in this way, the tester should perform the work while confirming the measured value, which is measured by the three-axis load cell 52 and displayed as described above.

[0045] Next, when the tester initiates the test start operation on the computer or other device used to operate the test apparatus 1, the control unit sends a release command signal to the brake means 6 to release the brake, and also sends a signal to the linear motor vibrator 3 to supply power to maintain its position. Upon receiving the release command signal, the brake means 6 introduces hydraulic fluid into the space within the case 661 on the rod 42 side of the flange portion 641, and when the distance between the sensor 62 and the metal member 67 exceeds a predetermined value, it sends a release completion signal to the control unit. Upon receiving the release completion signal, the control unit sends a vibration start signal to the linear motor vibrator 3 to start the vibration.

[0046] While the linear motor vibrator 3 is applying vibration to the shock absorber 100, the control unit monitors information about the vibration applied by the linear motor vibrator 3 (amplitude, frequency, phase, etc.) and receives information measured from the linear encoder 35 (time change in displacement). The control unit may output the monitored and measured information directly to the external device, or it may process it appropriately before outputting it to the external device.

[0047] At the end of the test, the tester performs a test termination operation on the computer or other device used to operate the test apparatus 1. This causes the control unit to transmit a vibration stop signal to the linear motor vibrator 3. Upon receiving the vibration stop signal, the linear motor vibrator 3 stops vibrating and maintains power supply to maintain this stopped position. After a predetermined time has elapsed since transmitting the vibration stop signal, or after determining that the linear motor vibrator 3 has stopped based on, for example, the measurement information from the linear encoder 35, the control unit transmits a hold command signal to the brake means 6. Upon receiving the hold command signal, the brake means 6 reduces the pressure in the space on the rod 42 side of the flange portion 641 within the case 661, and when the distance between the sensor 62 and the metal member 67 falls below a predetermined value, it transmits a hold completion signal to the control unit. Upon receiving the hold completion signal, the control unit transmits a power supply termination signal to the linear motor vibrator 3 and terminates the power supply for maintaining the stopped position.

[0048] Furthermore, if the time difference between the timing when the linear motor vibrator 3 starts or stops vibrating and the timing when the brake means 6 holds or releases the rod 42, and the distance the output unit 34 descends due to gravity during this time is short, then it is not necessary to supply power to maintain the position.

[0049] As described above, if the control unit does not receive a release completion signal after sending a release command signal to the brake means 6, a vibration start signal will not be sent to the linear motor vibrator 3, and therefore vibration will not start.

[0050] According to this embodiment, since the holding means 5 includes not only a displacement mechanism 51 but also a three-axis load meter 52 and a load control load cell, it is possible to measure the load applied to the shock absorber 100 in the X and Y directions while measuring the load in the Z direction (i.e., the characteristics of the shock absorber 100). That is, the upper end portion 102 of the shock absorber 100 can be positioned in the XY plane so that a desired load is applied to the shock absorber 100 in the XY plane, thereby improving the reproducibility of actual driving conditions.

[0051] Furthermore, since the guide roller 213 is pivotally supported so as to be rotatable around a rotation axis extending in a direction perpendicular to the vibration direction Z, and is immovable in the Z direction, contact between such a guide roller 213 and the flat portion 421 of the rod 42 can suppress displacement such as rotation (twisting) of the shock absorber 100 around an axis along the extension and contraction direction. Moreover, by combining a guide roller 213 with its axial direction in the X direction and a guide roller 213 with its axial direction in the Y direction, such displacement can be further suppressed.

[0052] Furthermore, by positioning the output section 34 between two pairs of rods 42 in the X direction, when the upper end 102 of the shock absorber 100 is displaced by the displacement mechanism 51, the displacement of the lower end connection section 101 in the X direction is suppressed, allowing for stable vibration application. In addition, since the four rods 42 form two pairs of rods 42 aligned in the Y direction, and the output section 34 extends along the Y direction, the displacement of the connection section 101 in the Y direction can also be suppressed.

[0053] Furthermore, because the direction in which the rods 42 are aligned coincides with the direction of displacement caused by the displacement mechanism 51, the displacement of the connection part 101 is easily suppressed, and vibration can be applied more stably.

[0054] Furthermore, since the holding means 5 has a triaxial load cell 52 and a load control load cell as two measuring units with different upper measurement limits, it is possible to select the measuring unit to use according to the load applied in a direction intersecting the expansion and contraction direction, thereby improving the degree of freedom in setting the load in a direction intersecting the expansion and contraction direction and improving the measurement accuracy.

[0055] Furthermore, the braking means 6 stops the movement of the rod 42 of the relay means 4 that transmits vibrations from the linear motor vibrator 3 to the shock absorber 100. This allows the position at the end of vibration to be maintained even after the power supply to the linear motor vibrator 3 is terminated, thereby reducing power consumption while maintaining the position at the end of vibration.

[0056] Furthermore, since the braking means 6 holds the outer circumferential surface 42A of the rod 42 of the relay means 4, there is no need to form a held part on the linear motor vibrator 3, making it easier to standardize the linear motor vibrator 3 among test devices with different specifications. In addition, the rod 42 is easier to configure to have high rigidity compared to the output section 34 of the linear motor vibrator 3. As a result, a large holding force (clamping force) can be applied to the rod 42, improving the reliability of position holding by the braking means 6.

[0057] Furthermore, by having the braking means 6 hold two diagonally opposite rods 42 of the four rods 42 arranged in a square shape in the relay means 4, it is possible to suppress tilting of the vibration table 41 when the position at the end of vibration is maintained by the braking means 6.

[0058] Furthermore, by having the braking means 6 hold a connection surface 422 on the outer circumferential surface 42A of the rod 42 that is different from the flat surface 421, the region on the outer circumferential surface 42A of the rod 42 can be made independent of the region that is subject to braking and the region that is guided during vibration in the Z direction. As a result, even if changes such as scratches or deformation occur on the outer circumferential surface 42A of the rod 42 due to repeated braking, it is less likely to affect the guidance of the rod 42 by the guide portion 212, and the rod 42 can be guided smoothly.

[0059] Furthermore, the braking means 6 has a compression spring 65 that generates a biasing force in the direction toward the rod 42 that is to be braked, and the hydraulic drive unit 66 generates a release force against the biasing force of the compression spring 65. This ensures that even if a malfunction occurs in the hydraulic drive unit 66 and no release force is generated, the compression spring 65 can maintain the cessation of movement in the Z direction. Additionally, by driving the linear motor exciter 3 when the control means receives a release completion signal, the linear motor exciter 3 can be prevented from being driven if the brake is not released due to some malfunction.

[0060] Furthermore, by starting the vibration of the linear motor vibrator 3 when the distance between the sensor 62 and the metal member 67 exceeds a predetermined value, it is possible to prevent the linear motor vibrator 3 from being driven while the clamping of the rod 42 by the pair of clamping parts 63 is not released. In addition, if a malfunction occurs in the sensor 62 or if there is a problem with communication between the sensor 62 and the control unit, the linear motor vibrator 3 will not be driven.

[0061] It should be noted that the present invention is not limited to the embodiments described above, and includes other configurations that can achieve the objectives of the present invention, and modifications such as those shown below are also included in the present invention. For example, in the above embodiment, two pairs of rods 42 sandwich a flat plate-shaped output section 34 from the X direction, but the rods may be appropriately arranged depending on the shape of the output section, and if the output section is rod-shaped, three or more rods may be arranged to surround the output section (preferably four rods arranged in a square shape). Also, when multiple rods are provided, the direction in which the rods are aligned and the direction of displacement by the displacement mechanism do not have to coincide.

[0062] Furthermore, in the above embodiment, the guide roller 213, which is rotatably supported around a rotation axis extending in a direction perpendicular to the vibration direction Z, contacts the flat portion 421 of the rod 42, that is, the guide roller 213 itself rotates without moving. However, the rod 42 may be guided by a configuration in which it rolls while in contact with the flat portion 421 of the rod 42, for example, using balls such as ball splines (i.e., making point contact), in which case the rod does not have a flat portion. Also, the manner of contact between the rod and the member guiding the rod is not limited to point contact, for example, the outer circumferential surface of the roller may be cylindrical and make linear contact with the flat portion of the rod in a cross-section as shown in Figure 4.

[0063] Furthermore, if displacement is unlikely to occur at one end of the shock absorber due to the shape, dimensions, and material of each part of the excitation means, the relay means may be configured without a relay body and rod. For example, the relay means may directly connect the output part of the excitation means and one end of the shock absorber.

[0064] Furthermore, in the above embodiment, the holding means 5 is provided with a triaxial load cell 52 and a load control load cell as two measuring units with different measurement ranges. However, depending on the type of shock absorber and measurement conditions, three or more measuring units may be provided, or only one measuring unit may be provided.

[0065] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design changes, etc., that do not depart from the spirit of the present invention are also included. [Explanation of Symbols]

[0066] 1…Test device, 3…Linear motor vibrator (vibration means), 4…Relay means, 41…Relay main body, 42…Rod, 5…Holding means, 51…Displacement mechanism, 52…3-axis load cell (load measuring unit, measuring unit), 100…Shock absorber, 101…Connecting part (one end), 102…Upper end (other end)

Claims

1. A test apparatus for measuring the characteristics of a shock absorber by applying vibration in the extension and contraction direction, An excitation means for generating vibrations, A relay means connected to the output section of the vibration excitation means and one end of the shock absorber to transmit vibrations, The shock absorber comprises a retaining means for holding the other end of the shock absorber, The holding means includes a displacement mechanism that displaces the other end in at least one direction in a plane intersecting the extension direction, and a load measuring unit that measures the load applied to the other end. The test apparatus is characterized in that the load measuring unit measures the load in the expansion and contraction direction and the load in at least two directions in a plane intersecting the expansion and contraction direction.

2. The relay means comprises a relay body portion extending along a plane intersecting the extension direction, and a plurality of rods connected to the relay body portion. The outer circumferential surface of the rod has a plurality of planar portions extending along a plane including the vibration direction, The test apparatus according to claim 1, characterized in that the planar portion is guided by a roller that is rotatably supported around a rotation axis extending in a direction perpendicular to the vibration direction.

3. The relay means comprises a relay body portion extending along a plane intersecting the extension direction, and a plurality of rods connected to the relay body portion and extending along the extension direction and guided along the extension direction. The test apparatus according to claim 1, wherein the plurality of rods include a pair of rods, and the output section is located between the pair of rods in a direction intersecting the extension and retraction direction, or includes three or more rods arranged to surround the output section.

4. The test apparatus according to claim 1 or 2, characterized in that the load measuring section includes two measuring sections whose upper measurement limits differ from each other in the expansion and contraction direction.

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