Cylinder drive system and vibration test equipment

Abstract

To suppress discontinuous change of hydraulic pressure at the time when a movement direction of a rod changes, and suppress deterioration of versatility, in a cylinder drive system and a vibration test device.SOLUTION: A cylinder drive system of the present invention comprises: a fluid cylinder device in which the inside of a cylinder is partitioned into a first chamber and a second chamber by a piston, and a rod connected to the piston extends outside through the second chamber; a first flow rate adjustment device capable of adjusting a first supply / discharge amount of fluid to / from the first chamber; a second flow adjustment device capable of adjusting a second supply / discharge amount of fluid to / from the second chamber; and a control device that controls the first flow rate adjustment device and the second flow rate adjustment device such that the first supply / discharge amount and the second supply / discharge amount differ according to a pressure receiving area ratio of the first chamber and the second chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to, for example, a cylinder drive system for driving a hydraulic cylinder and a vibration test device. [Background technology]

[0002] Vibration testing equipment is known that vibrates a vibration table on which an object is placed. By using a single-rod type vibration exciter, the overall length of the vibration testing equipment can be shortened, thereby saving space. A single-rod type vibration exciter is composed of, for example, a single-rod hydraulic cylinder and a hydraulic servo valve. The hydraulic servo valve supplies and discharges hydraulic pressure to two chambers partitioned inside the hydraulic cylinder, causing the rod to extend or retract.

[0003] In a single-rod hydraulic cylinder, the hydraulic pressure supplied to each chamber changes discontinuously when the rod switches between extending and retracting. In a single-rod hydraulic cylinder, the rod is connected to a piston that separates each chamber by penetrating one of the chambers from the outside, resulting in different cross-sectional areas for each chamber. Therefore, the pressure in each chamber varies depending on the cross-sectional area. Furthermore, the flow rate supplied to or discharged from each chamber of the hydraulic cylinder varies depending on the cross-sectional area. A hydraulic servo valve supplies and discharges oil to and from each chamber of the hydraulic cylinder through the same opening area, but this same opening area results in discontinuous changes in the hydraulic pressure in each chamber. A technology that addresses this issue is described, for example, in Patent Document 1 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-132706 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology described in the aforementioned Patent Document 1 determines the first supply opening width and first discharge opening width of the hydraulic servo valve for the first hydraulic chamber and the second supply opening width and second discharge opening width of the hydraulic servo valve for the second hydraulic chamber based on the cross-sectional area ratio between the first hydraulic chamber and the second hydraulic chamber of the hydraulic cylinder. However, this requires processing to form the supply opening width and the discharge opening width based on the cross-sectional area ratio between the hydraulic chambers of the hydraulic cylinder, which increases processing costs. In addition, because a specific hydraulic servo valve is manufactured for a single-rod hydraulic cylinder, the hydraulic servo valve cannot be applied to other hydraulic cylinders, resulting in a problem of reduced versatility.

[0006] The present disclosure is intended to solve the above-mentioned problems, and aims to provide a cylinder drive system and a vibration testing device that suppress discontinuous changes in hydraulic pressure when the direction of rod movement is switched and suppress a decrease in versatility. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the cylinder drive system of the present disclosure includes a fluid cylinder device in which the inside of a cylinder is divided into a first chamber and a second chamber by a piston, and a rod connected to the piston extends to the outside through the second chamber, a first flow rate adjustment device that can adjust a first supply / discharge rate of fluid to the first chamber, a second flow rate adjustment device that can adjust a second supply / discharge rate of fluid to the second chamber, and a control device that controls the first flow rate adjustment device and the second flow rate adjustment device so that the first supply / discharge rate and the second supply / discharge rate differ depending on the pressure-receiving area ratio between the first chamber and the second chamber.

[0008] The vibration testing apparatus of the present disclosure also includes a base portion, a vibration table supported on the base portion so as to be freely movable, and the cylinder drive system supported on the base portion, with the tip of the rod connected to the vibration table. [Effects of the Invention]

[0009] According to the cylinder drive system and vibration testing device of the present disclosure, it is possible to suppress discontinuous changes in hydraulic pressure when the moving direction of the rod is switched, and also to suppress a decrease in versatility. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a vibration testing device to which the cylinder drive system of the first embodiment is applied. [Figure 2] FIG. 2 is a schematic diagram showing the control blocks of the cylinder drive system. [Figure 3] FIG. 3 is a schematic diagram showing a control block for setting the first supply / discharge amount and the second supply / discharge amount. [Figure 4] FIG. 4 is a schematic diagram for explaining the operation of the cylinder drive system. [Figure 5] FIG. 5 is a graph showing pressure fluctuations in a conventional cylinder drive system. [Figure 6] FIG. 6 is a graph showing pressure fluctuations in the cylinder drive system of the first embodiment. [Figure 7] FIG. 7 is a schematic diagram illustrating a cylinder drive system according to the second embodiment. [Figure 8] FIG. 8 is a schematic diagram for explaining the operation of the cylinder drive system. DETAILED DESCRIPTION OF THE INVENTION

[0011] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to these embodiments, and when there are multiple embodiments, the present disclosure also includes configurations that combine the embodiments. Furthermore, the components in the embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially identical, and those that are within the so-called equivalent range.

[0012] [First embodiment] <Vibration testing equipment> FIG. 1 is a schematic diagram showing the configuration of a vibration testing device to which the cylinder drive system of the first embodiment is applied.

[0013] As shown in FIG. 1, the vibration testing device 10 includes a base unit 11, a vibration table 12, and a cylinder drive system 13.

[0014] The base unit 11 is placed on a horizontal floor surface. A horizontal support surface 11a is formed on the upper part of the base unit 11. A guide rail 21 of a predetermined length is fixed to the support surface 11a of the base unit 11. The vibration table 12 is in the shape of a flat plate. A vibration target 200, such as a structure to be subjected to a vibration test, can be placed and fixed on the vibration table 12. A guide member 22 is fixed to the lower part of the vibration table 12. The guide member 22 is movably fitted into the guide rail 21. The vibration table 12 is supported on the base unit 11 via the guide member 22 and the guide rail 21 so as to be movably along the horizontal direction.

[0015] The cylinder drive system 13 functions as a vibration device. The cylinder drive system 13 is capable of vibrating a vibration target 200 fixed to the vibration table 12. The cylinder drive system 13 includes a hydraulic cylinder (fluid cylinder device) 30, a first servo valve (first flow rate control device) 31, a second servo valve (second flow rate control device) 32, and a control device 33.

[0016] The hydraulic cylinder 30 has a cylinder 41, a piston 42, and a rod 43. The cylinder 41 is cylindrical and has one and the other longitudinal ends closed. The piston 42 is disk-shaped and is supported inside the cylinder 41 so as to be able to move freely. The interior of the cylinder 41 is divided into a first chamber 44 and a second chamber 45 by the piston 42. The rod 43 passes through the second chamber 45 of the cylinder 41, with one axial end connected to the piston 42 and the other axial end extending outward from the cylinder 41. The hydraulic cylinder 30 has a tip end of the rod 43 connected to an end of the vibration table 12 by a connecting member 23.

[0017] Therefore, the vibration testing device 10 drives the hydraulic cylinder 30 in the cylinder driving system 13 to move the vibration table 12 back and forth in the horizontal direction, thereby vibrating the vibration target 200 placed on the vibration table 12.

[0018] <Cylinder drive system configuration> As described above, the cylinder drive system 13 includes the hydraulic cylinder 30, the first servo valve 31, the second servo valve 32, and the control device 33. The first servo valve 31 is a spool valve and is capable of adjusting a first supply / discharge rate of oil (fluid) supplied to / discharged from the first chamber 44 of the hydraulic cylinder 30. The second servo valve 32 is a spool valve and is capable of adjusting a second supply / discharge rate of oil (fluid) supplied to / discharged from the second chamber 45 of the hydraulic cylinder 30. The control device 33 is capable of controlling the drive of the first servo valve 31 and the second servo valve 32.

[0019] The hydraulic cylinder 30 is provided with a first supply / discharge port 46 in communication with the first chamber 44 in the cylinder 41, and a second supply / discharge port 47 in communication with the second chamber 45.

[0020] The first servo valve 31 has a case 51, a spool 52, and a drive unit 53. The case 51 is cylindrical and is provided with a first supply / discharge unit 61, a second supply / discharge unit 62, a hydraulic pressure supply unit 63, a first hydraulic pressure discharge unit 64, and a second hydraulic pressure discharge unit 65. The spool 52 is cylindrical and is housed inside the case 51 and is movable in the axial direction. The spool 52 has a first valve body 66, a second valve body 67, and a third valve body 68. The first valve body 66 is capable of opening and closing the hydraulic pressure supply unit 63, the second valve body 67 is capable of opening and closing the first hydraulic pressure discharge unit 64, and the third valve body 68 is capable of opening and closing the second hydraulic pressure discharge unit 65.

[0021] The drive unit 53 is disposed outside the case 51 and is capable of reciprocating the spool 52 in the axial direction.

[0022] The second servo valve 32 has a case 71, a spool 72, and a drive unit 73. The case 71 is cylindrical and is provided with a first supply / discharge unit 81, a second supply / discharge unit 82, a hydraulic pressure supply unit 83, a first hydraulic pressure discharge unit 84, and a second hydraulic pressure discharge unit 85. The spool 72 is cylindrical and is housed inside the case 71 and is movable in the axial direction. The spool 72 has a first valve body 86, a second valve body 87, and a third valve body 88. The first valve body 86 is capable of opening and closing the hydraulic pressure supply unit 83, the second valve body 87 is capable of opening and closing the first hydraulic pressure discharge unit 84, and the third valve body 88 is capable of opening and closing the second hydraulic pressure discharge unit 85.

[0023] The drive unit 73 is disposed outside the case 71 and is capable of reciprocating the spool 72 in the axial direction.

[0024] The first servo valve 31 has a first supply / discharge section 61 connected to the first supply / discharge port 46 of the hydraulic cylinder 30 by a flow path 91, and a second supply / discharge section 62 closed. The second servo valve 32 has a first supply / discharge section 81 closed, and a second supply / discharge section 62 connected to the second supply / discharge port 47 of the hydraulic cylinder 30 by a flow path 92.

[0025] The cylinder drive system 13 includes a hydraulic pump 34. The hydraulic pump 34 is connected to the hydraulic pressure supply unit 63 of the first servo valve 31 by a flow path 101, and is also connected to the hydraulic pressure supply unit 83 of the second servo valve 32 by a flow path 102. The hydraulic pump 34 is also connected to a tank 104 by a flow path 103, and a relief valve 105 is provided in the flow path 103.

[0026] The first servo valve 31 has a first hydraulic pressure discharge port 64 connected to a tank 104 by a flow path 106, and a second hydraulic pressure discharge port 65 connected to the tank 104 by a flow path 107. The second servo valve 32 has a first hydraulic pressure discharge port 84 connected to the tank 104 by a flow path 108, and a second hydraulic pressure discharge port 85 connected to the tank 104 by a flow path 109.

[0027] The control device 33 can drive and control the drive unit 53 of the first servo valve 31 and the drive unit 73 of the second servo valve 32. The control device 33 drives and controls the drive unit 53 in the first servo valve 31 to move the spool 52 and control the supply of oil to the first chamber 44 of the hydraulic cylinder 30 and the discharge of oil from the first chamber 44. The control device 33 also drives and controls the drive unit 73 in the second servo valve 32 to move the spool 72 and control the supply of oil to the second chamber 45 of the hydraulic cylinder 30 and the discharge of oil from the second chamber 45.

[0028] 1, in the first servo valve 31, the first valve body 66 connects the hydraulic pressure supply portion 63 to the first supply / discharge portion 61, the second valve body 67 closes the first hydraulic discharge portion 64, and the third valve body 68 opens the second hydraulic discharge portion 65. In other words, in the first servo valve 31, the flow path 101 and the flow path 91 connect with each other via the hydraulic pressure supply portion 63 and the first supply / discharge portion 61, and the other flow paths 106 and 107 are closed. At this time, in the second servo valve 32, when the spool 72 moves to the right in FIG. 1, the first valve body 86 connects the hydraulic pressure supply portion 83 to the first supply / discharge portion 81, the second valve body 87 closes the first hydraulic discharge portion 84, and the third valve body 88 opens the second hydraulic discharge portion 85. That is, in the second servo valve 32, the flow path 109 and the flow path 92 communicate with each other through the second hydraulic pressure discharge portion 85 and the second supply / discharge portion 82, and the other flow paths 102 and 108 are closed.

[0029] Then, by driving the hydraulic pump 34, oil is supplied to the hydraulic pressure supply portion 63 of the first servo valve 31 via flow path 101, passes through the inside of the case 51, and from the first supply / discharge portion 61 through flow path 91, and is supplied from the first supply / discharge port 46 of the hydraulic cylinder 30 to the first chamber 44. Meanwhile, oil in the second chamber 45 of the hydraulic cylinder 30 is discharged from the second supply / discharge port 47 through flow path 92 to the second supply / discharge portion 82 of the second servo valve 32, passes through the inside of the case 71, and is discharged from the second hydraulic pressure discharge portion 85 through flow path 109 to the tank 104. As a result, in the hydraulic cylinder 30, the piston 42 is pushed to the right in FIG. 1, and the rod 43 is extended.

[0030] 1, in the first servo valve 31, the first valve body 66 connects the hydraulic pressure supply port 63 to the second supply / discharge port 62, the second valve body 67 connects the first hydraulic pressure discharge port 64 to the first supply / discharge port 61, and the third valve body 68 closes the second hydraulic pressure discharge port 65. In other words, in the first servo valve 31, the flow path 106 and the flow path 91 connect via the first hydraulic pressure discharge port 64 and the first supply / discharge port 61, and the other flow paths 101 and 107 are closed. At this time, in the second servo valve 32, when the spool 72 connects to the left in FIG. 1, the first valve body 86 connects the hydraulic pressure supply port 83 to the second supply / discharge port 82, the second valve body 87 connects the first hydraulic pressure discharge port 84 to the first supply / discharge port 81, and the third valve body 88 closes the second hydraulic pressure discharge port 85. That is, in the second servo valve 32, the flow path 102 and the flow path 92 are communicated by the hydraulic supply unit 83 and the second supply / discharge unit 82, and the other flow paths 108 and 109 are closed.

[0031] Then, by driving the hydraulic pump 34, oil is supplied to the hydraulic pressure supply portion 83 of the second servo valve 32 via the flow path 102, passes through the inside of the case 71, and from the second supply / discharge portion 82 through the flow path 92, and is supplied from the second supply / discharge port 47 of the hydraulic cylinder 30 to the second chamber 45. Meanwhile, oil in the first chamber 44 of the hydraulic cylinder 30 is discharged from the first supply / discharge port 46 through the flow path 91 to the first supply / discharge portion 61 of the first servo valve 31, passes through the inside of the case 51, and is discharged from the first hydraulic pressure discharge portion 64 through the flow path 106 to the tank 104. As a result, in the hydraulic cylinder 30, the piston 42 is pushed leftward in FIG. 1 and the rod 43 is retracted.

[0032] The control device 33 also performs feedback control of the hydraulic cylinder 30. The hydraulic cylinder 30 is provided with a detection unit (drive amount detection unit) 48 that detects the movement amount of the piston 42 as the drive amount. The detection unit 48 outputs the detection result to the control device 33. The control device 33 feedback controls the first servo valve 31 and the second servo valve 32 based on the detection result of the detection unit 48. That is, the control device 33 compares the target movement amount of the piston 42 with the actual movement amount (detection result of the detection unit 48), and corrects the first supply / discharge amount and the second supply / discharge amount of the first servo valve 31 and the second servo valve 32.

[0033] <Cylinder drive system control> FIG. 2 is a schematic diagram showing a control block of the cylinder drive system, and FIG. 3 is a schematic diagram showing a control block for setting the first supply / discharge amount and the second supply / discharge amount.

[0034] 1, the control device 33 controls the first servo valve 31 and the second servo valve 32 so that the first supply / discharge rate and the second supply / discharge rate differ depending on the pressure-receiving area ratio between the first chamber 44 and the second chamber 45 in the hydraulic cylinder 30. The control device 33 sets the first supply / discharge rate depending on the target supply / discharge rate, and sets the second supply / discharge rate depending on the first supply / discharge rate.

[0035] The hydraulic cylinder 30 is a so-called single-rod fluid cylinder. Specifically, the hydraulic cylinder 30 is configured such that the interior of a cylinder 41 is divided into a first chamber 44 and a second chamber 45 by a piston 42, and a rod 43 penetrates the second chamber 45 and is connected to the piston 42. Therefore, when hydraulic pressure is supplied to the first chamber 44 and the second chamber 45, the pressure-receiving areas thereof are different. In other words, when the pressure-receiving area of ​​the first chamber 44 is A1 and the pressure-receiving area of ​​the second chamber 45 is A2, A1 > A2. Therefore, if oil is supplied to and discharged from the first chamber 44 and the second chamber 45 through the same opening area, the pressures acting on the first chamber 44 and the second chamber 45 will be different when the movement direction of the rod 43 is switched, resulting in a sudden change in the pressure in the chambers 44 and 45.

[0036] Therefore, in the first embodiment, when the hydraulic cylinder 30 is driven, the supply and discharge amounts to the first chamber 44 and the second chamber 45 are made different depending on the pressure-receiving area ratio between the first chamber 44 and the second chamber 45. That is, when the rod 43 is extended, the control device 33 sets the second discharge amount (second supply and discharge amount) from the second chamber 45 to be less than the first supply amount (first supply and discharge amount) to the first chamber 44. On the other hand, when the rod 43 is retracted, the control device 33 sets the second supply amount (second supply and discharge amount) to the second chamber 45 to be less than the first discharge amount (first supply and discharge amount) from the first chamber 44.

[0037] In the vibration testing device 10, test specifications are set according to the vibration target object 200 (see FIG. 1 for both), and a target movement amount of the piston 42, which is the drive amount of the hydraulic cylinder 30, is set. A target supply / discharge amount to be supplied to and discharged from the first chamber 44 and the second chamber 45 is set according to the target movement amount of the piston 42. A target movement amount of the spool 52 of the first servo valve 31 and the spool 72 of the second servo valve 32 is set according to the target supply / discharge amount.

[0038] As shown in FIG. 2, the control device 33 sets a target supply / discharge amount based on the target movement amount of the piston 42, and determines a target movement amount (target stroke) S of the spools 52, 72 in the servo valves 31, 32 in response to the target supply / discharge amount. T The processing unit 110 sets the target movement amount S of the spools 52 and 72. T is set as the first movement amount S1 of the spool 52. The first movement amount S1 is input to the comparison unit 112 via the branch unit 111. The comparison unit 112 compares the first movement amount S1 with the actual first movement amount S fed back from the branch unit 114. D1 and subtraction is performed to calculate the deviation ΔS1. The deviation ΔS1 is output to the drive unit 53 of the first servo valve 31 via the amplifier 113. The drive unit 53 operates (extends or contracts) the spool 52 in accordance with the deviation ΔS1.

[0039] The memory unit 115a and the calculation unit 116a perform processing when the spool 72 of the second servo valve 32 is extended, and the memory unit 115b and the calculation unit 116b perform processing when the spool 72 is retracted. The memory unit 115a stores a map indicating a second movement amount S2 of the spool 72 relative to a first movement amount S1 of the spool 52. The calculation unit 116a calculates the second movement amount S2 based on the map. The memory unit 115b stores a map indicating a second movement amount S2 of the spool 72 relative to the first movement amount S1 of the spool 52 when the spool 72 is retracted. The calculation unit 116b calculates the second movement amount S2 based on the map. The addition unit 117 adds the second movement amount S2 calculated by the calculation unit 116a and the second movement amount S2 calculated by the calculation unit 116b.

[0040] The second movement amount S2 is input to the comparison unit 118. The comparison unit 118 compares the second movement amount S2 with the actual first movement amount S fed back from the branch unit 120. D2 and subtraction is performed to calculate the deviation ΔS2. The deviation ΔS2 is output to the drive unit 73 of the second servo valve 32 via the amplifier 119. The drive unit 73 operates (extends or contracts) the spool 72 in accordance with the deviation ΔS2.

[0041] Here, a specific description will be given of the processing of the storage unit 115 and the calculation unit 116. As shown in FIG. T is set as the first movement amount of the spool 52. The memory unit 115 stores a map showing the second movement amount S2 of the spool 72 relative to the first movement amount S1 of the spool 52. In the map of the memory unit 115, the dotted line represents the relationship between the conventional first movement amount S1 and the second movement amount S2, and the solid line represents the relationship between the first movement amount S1 and the second movement amount S2 of the first embodiment.

[0042] In the map, the first movement amount S1 of the spool 52 and the second movement amount S2 of the spool 72 are proportional to each other. In the conventional map, the first movement amount S1 of the spool 52 and the second movement amount S2 of the spool 72 are the same value. In contrast, in the map of the first embodiment, the first movement amount S1 of the spool 52 and the second movement amount S2 of the spool 72 are different values. Specifically, the first movement amount S1 of the spool 52 and the second movement amount S2 of the spool 72 are set according to the pressure-receiving area ratio between the first chamber 44 and the second chamber 45. Here, the pressure-receiving area A1 is greater than the pressure-receiving area A2. Therefore, when the rod 43 of the hydraulic cylinder 30 is extended, the second movement amount S2 of the spool 72, i.e., the second discharge amount (second supply / discharge amount) from the second chamber 45, is less than the first movement amount S1 of the spool 52, i.e., the first supply amount (first supply / discharge amount) to the first chamber 44. Similarly, when the rod 43 of the hydraulic cylinder 30 is contracted, the second movement amount S2 of the spool 72, i.e., the second supply amount (second supply / discharge amount) to the second chamber 45, is less than the first movement amount S1 of the spool 52, i.e., the first discharge amount (first supply / discharge amount) from the first chamber 44. Note that the first supply / discharge amount to the first chamber 44 and the first movement amount S1 of the spool 52 of the first servo valve 31 are proportional to each other. Also, the second supply / discharge amount to the first chamber 44 and the second movement amount S2 of the spool 72 of the second servo valve 32 are proportional to each other.

[0043] For example, the pressure receiving area A1 of the first chamber 44 is 1.0, and the pressure receiving area A2 of the second chamber 45 is 0.8. When the rod 43 of the hydraulic cylinder 30 is extended, the pressure receiving area ratio of the first chamber 44 to the second chamber 45 is A2 / A1=0.8 / 1.0=0.8. Therefore, the first movement amount S1 of the spool 52 is S T ×1.0=S T Therefore, the second movement amount S2 of the spool 72 is S1=S1×0.8=0.8S1. On the other hand, when the rod 43 of the hydraulic cylinder 30 is contracted, the pressure receiving area ratio of the first chamber 44 to the second chamber 45 is A2 / A1=0.8 / 1.0=0.8. Therefore, the first movement amount S1 of the spool 52 is S T ×1.0=S T and the second movement amount S2 of the spool 72 is S1=S1×0.8=0.8S1.

[0044] The control device 33 calculates the first movement amount S1 of the spool 52 and the second movement amount S2 of the spool 72, and controls the first servo valve 31 based on the first movement amount S1 and the second servo valve 32 based on the second movement amount S2. However, what the control device 33 actually outputs to each drive unit 53, 73 are the first control command value and the second control command value set according to the first movement amount S1 and the second movement amount S2.

[0045] In the above description, the target supply / discharge amount is set based on the target movement amount of the piston 42, and the target movement amount (target stroke) S of the spools 52, 72 in the servo valves 31, 32 is set based on the target supply / discharge amount. T Set the target movement amount S T is set as the first movement amount S1 of the spool 52, and the second movement amount S2 is set based on the first movement amount S1 and the pressure-receiving area ratio, but the present invention is not limited to this method. For example, a target supply / discharge amount may be set based on a target movement amount of the piston 42, the target supply / discharge amount may be set as a first supply / discharge amount to the first chamber 44, the first movement amount S1 of the spool 52 may be set based on the first supply / discharge amount, a second supply / discharge amount to the second chamber 45 may be set based on the pressure-receiving area ratio based on the first supply / discharge amount, and the second movement amount S2 of the spool 72 may be set based on the second supply / discharge amount.

[0046] Furthermore, in the above description, it is assumed that the first servo valve 31 and the second servo valve 32 have the same configuration and dimensions, but the first servo valve 31 and the second servo valve 32 do not have to have the same configuration and dimensions. In this case as well, the first movement amount S1 of the first servo valve 31 and the second movement amount S2 of the second servo valve 32 may be set so that the first supply / discharge amount and the second supply / discharge amount differ depending on the pressure-receiving area ratio between the first chamber 44 and the second chamber 45 in the hydraulic cylinder 30.

[0047] <Operation of the cylinder drive system> FIG. 4 is a schematic diagram for explaining the operation of the cylinder drive system.

[0048] 1 and 4, when the rod 43 of the hydraulic cylinder 30 is extended, the control device 33 moves the spool 52 of the first servo valve 31 to the right in FIG. 4 by a first movement amount S1. This causes the hydraulic pressure supply portion 63 to communicate with the first supply / discharge portion 61, and the first hydraulic pressure discharge portion 64 and the second hydraulic pressure discharge portion 65 are closed. In addition, the control device 33 moves the spool 72 of the second servo valve 32 to the right in FIG. 4 by a second movement amount S2. This causes the second hydraulic pressure discharge portion 85 to communicate with the second supply / discharge portion 82, and the hydraulic pressure supply portion 83 and the first hydraulic pressure discharge portion 84 are closed.

[0049] At this time, the control device 33 sets the first movement amount S1 and the second movement amount S2 according to the pressure-receiving area ratio A2 / A1 between the first chamber 44 and the second chamber 45, so the second movement amount S2 is smaller than the first movement amount S1. That is, the communication opening between the second hydraulic pressure discharge portion 85 and the second supply / discharge portion 82 in the second servo valve 32 is smaller than the communication opening between the hydraulic pressure supply portion 63 and the first supply / discharge portion 61 in the first servo valve 31. Then, the second discharge amount of oil discharged from the second chamber 45 of the hydraulic cylinder 30 through the flow path 92 to the second servo valve 32 becomes smaller than the first supply amount of oil supplied from the first servo valve 31 through the flow path 91 to the first chamber 44 of the hydraulic cylinder 30.

[0050] Therefore, when the rod 43 of the hydraulic cylinder 30 extends and the piston 42 moves to the right in Figure 4, the ratio of the flow rate supplied to the first chamber 44 to the flow rate discharged from the second chamber 45 becomes equal to the cross-sectional area ratio of each chamber, and pressure fluctuations (discontinuous changes in hydraulic pressure) in the first chamber 44 and the second chamber 45 are reduced.

[0051] Furthermore, when the rod 43 of the hydraulic cylinder 30 is contracted, the control device 33 moves the spool 52 of the first servo valve 31 leftward in FIG. 4 by a first movement amount S1. This causes the first hydraulic pressure discharge port 64 to communicate with the first supply / discharge port 61, and closes the hydraulic pressure supply port 63 and the second hydraulic pressure discharge port 65. Furthermore, the control device 33 moves the spool 72 of the second servo valve 32 leftward in FIG. 4 by a second movement amount S2. This causes the hydraulic pressure supply port 83 to communicate with the second supply / discharge port 82, and closes the first hydraulic pressure discharge port 84 and the second hydraulic pressure discharge port 85.

[0052] At this time, the control device 33 sets the first movement amount S1 and the second movement amount S2 according to the pressure-receiving area ratio A2 / A1 between the first chamber 44 and the second chamber 45, so the second movement amount S2 is smaller than the first movement amount S1. That is, the communication opening between the hydraulic pressure supply portion 83 and the second supply / discharge portion 82 in the second servo valve 32 is smaller than the communication opening between the first hydraulic pressure discharge portion 64 and the first supply / discharge portion 61 in the first servo valve 31. Then, the second supply amount of oil supplied from the second servo valve 32 through the flow path 92 to the second chamber 45 of the hydraulic cylinder 30 becomes smaller than the first discharge amount of oil discharged from the first chamber 44 of the hydraulic cylinder 30 through the flow path 91 to the first servo valve 31.

[0053] Therefore, when the rod 43 of the hydraulic cylinder 30 extends and the piston 42 moves to the left in Figure 4, the ratio of the flow rate discharged from the first chamber 44 to the flow rate supplied to the second chamber 45 becomes equal to the cross-sectional area ratio of each chamber, and pressure fluctuations (discontinuous changes in hydraulic pressure) in the first chamber 44 and the second chamber 45 are reduced.

[0054] <Effects of the cylinder drive system> Fig. 5 is a graph showing pressure fluctuations in a conventional cylinder drive system, and Fig. 6 is a graph showing pressure fluctuations in the cylinder drive system of the first embodiment. In Fig. 5 and Fig. 6, the solid line represents the pressure in the first chamber 44, and the dotted line represents the pressure in the second chamber 45.

[0055] As shown in Figure 5, in the conventional cylinder drive system, the same amount of oil is supplied to and discharged from the first chamber 44 and the second chamber 45 of the hydraulic cylinder 30. Therefore, at times t1, t2, t3, t4, t5, etc. when the movement direction of the rod 43 switches, the pressure acting on the first chamber 44 and the second chamber 45 differs, causing a sudden rise in the pressure in each chamber 44, 45.

[0056] On the other hand, the cylinder drive system 13 of the first embodiment supplies and discharges oil to and from the first chamber 44 and the second chamber 45 of the hydraulic cylinder 30 in an amount according to the pressure-receiving area ratio, so that at times t1, t2, t3, t4, t5, etc. when the movement direction of the rod 43 switches, the pressures acting on the first chamber 44 and the second chamber 45 become similar, and the increase in pressure in each chamber 44, 45 is suppressed.

[0057] [Second embodiment] Fig. 7 is a schematic diagram showing a cylinder drive system of the second embodiment, and Fig. 8 is a schematic diagram for explaining the operation of the cylinder drive system. Note that members having the same functions as those in the first embodiment described above are given the same reference numerals and detailed descriptions thereof will be omitted.

[0058] 7, the cylinder drive system 13A includes a hydraulic cylinder 30, a first servo valve 31, a second servo valve 32, and a control device 33 (see FIG. 1). The basic configurations of the hydraulic cylinder 30, the first servo valve 31, and the second servo valve 32 are the same as those in the first embodiment.

[0059] The hydraulic cylinder 30 has a cylinder 41, a piston 42, and a rod 43, and is internally partitioned into a first chamber 44 and a second chamber 45. In the hydraulic cylinder 30, first supply / discharge ports 46a and 46b are provided in the first chamber 44, and second supply / discharge ports 47a and 47b are provided in the second chamber 45. A first shutoff valve 131 is provided in the first supply / discharge port 46b, and a second shutoff valve 132 is provided in the second supply / discharge port 47b.

[0060] The first servo valve 31 has a case 51, a spool 52, and a drive unit 53. The second servo valve 32 has a case 71, a spool 72, and a drive unit 73. The first servo valve 31 has a first supply / discharge unit 61 connected to the first supply / discharge port 46a of the hydraulic cylinder 30 by a flow path 91a, and a second supply / discharge unit 62 connected to the second supply / discharge port 47b of the hydraulic cylinder 30 by a flow path 92b. The second servo valve 32 has a first supply / discharge unit 81 connected to the first supply / discharge port 46b of the hydraulic cylinder 30 by a flow path 91b, and a second supply / discharge unit 62 connected to the second supply / discharge port 47a of the hydraulic cylinder 30 by a flow path 92a.

[0061] The first shutoff valve 131 may be provided in the first supply / discharge section 81 or the flow path 91b, and the second shutoff valve 132 may be provided in the second supply / discharge section 62 or the flow path 92b.

[0062] The control device 33 (see FIG. 1) can drive and control the drive unit 53 of the first servo valve 31 and the drive unit 73 of the second servo valve 32. In the first servo valve 31, the control device 33 drives and controls the drive unit 53 to move the spool 52, thereby controlling the supply of oil to the first chamber 44 of the hydraulic cylinder 30 and the discharge of oil from the first chamber 44. The control device 33 also drives and controls the drive unit 73 to move the spool 72, thereby controlling the supply of oil to the second chamber 45 of the hydraulic cylinder 30 and the discharge of oil from the second chamber 45.

[0063] Furthermore, the control device 33 can control the opening and closing of the first shut-off valve 131 and the second shut-off valve 132. When the first shut-off valve 131 and the second shut-off valve 132 are closed by the control device 33, the cylinder drive system 13A of the second embodiment functions in the same manner as the cylinder drive system 13 of the first embodiment. On the other hand, when the first shut-off valve 131 and the second shut-off valve 132 are opened by the control device 33, the cylinder drive system 13A of the second embodiment functions differently from the cylinder drive system 13 of the first embodiment.

[0064] When the first shutoff valve 131 and the second shutoff valve 132 are closed by the control device 33, the control device 33 controls the first servo valve 31 and the second servo valve 32 so that the first supply / discharge rate and the second supply / discharge rate differ according to the pressure-receiving area ratio between the first chamber 44 and the second chamber 45 in the hydraulic cylinder 30. The operation in this case is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0065] As shown in Figure 8, when the first shut-off valve 131 and the second shut-off valve 132 are opened by the control device 33, the control device 33 controls the first servo valve 31 and the second servo valve 32 so that the first supply / discharge amount and the second supply / discharge amount are the same regardless of the pressure-receiving area ratio between the first chamber 44 and the second chamber 45 in the hydraulic cylinder 30.

[0066] That is, the control device 33 opens the first shutoff valve 131 and the second shutoff valve 132. In this state, when the spool 52 of the first servo valve 31 moves to the right in Fig. 8, the first valve body 66 connects the hydraulic pressure supply portion 63 to the first supply / discharge portion 61, the second valve body 67 closes the first hydraulic discharge portion 64, and the third valve body 68 connects the second hydraulic discharge portion 65 to the second supply / discharge portion 62. At this time, when the spool 72 of the second servo valve 32 moves to the right in Fig. 8, the first valve body 86 connects the hydraulic pressure supply portion 83 to the first supply / discharge portion 81, the second valve body 87 closes the first hydraulic discharge portion 84, and the third valve body 88 connects the second hydraulic discharge portion 85 to the first supply / discharge portion 81.

[0067] Then, oil supplied to the hydraulic pressure supply unit 63 of the first servo valve 31 passes through the first supply / discharge unit 61 and the flow path 91a, and is supplied from the first supply / discharge port 46a of the hydraulic cylinder 30 to the first chamber 44. Also, oil in the second chamber 45 of the hydraulic cylinder 30 is discharged from the second supply / discharge port 47b through the flow path 92b to the second supply / discharge unit 62 of the first servo valve 31, and is then discharged to the second hydraulic pressure discharge unit 65. Similarly, in the second servo valve 32, oil supplied to the hydraulic pressure supply unit 83 passes through the first supply / discharge unit 81 and the flow path 91b, and is supplied from the first supply / discharge port 46b of the hydraulic cylinder 30 to the first chamber 44. Also, oil in the second chamber 45 of the hydraulic cylinder 30 is discharged from the second supply / discharge port 47a through the flow path 92a to the second supply / discharge unit 82 of the second servo valve 32, and is then discharged to the second hydraulic pressure discharge unit 85. As a result, a large amount of oil is supplied to and discharged from the first chamber 44 and the second chamber 45 of the hydraulic cylinder 30, the piston 42 is quickly pushed rightward in FIG. 8, and the rod 43 is quickly extended.

[0068] On the other hand, in the first servo valve 31, when the spool 52 moves leftward in Fig. 8, the first valve body 66 connects the hydraulic pressure supply portion 63 to the second supply / discharge portion 62, the second valve body 67 connects the first hydraulic pressure discharge portion 64 to the first supply / discharge portion 61, and the third valve body 68 closes the second hydraulic pressure discharge portion 65. At this time, in the second servo valve 32, when the spool 72 moves leftward in Fig. 8, the first valve body 86 connects the hydraulic pressure supply portion 83 to the second supply / discharge portion 82, the second valve body 87 connects the first hydraulic pressure discharge portion 84 to the first supply / discharge portion 81, and the third valve body 88 closes the second hydraulic pressure discharge portion 85.

[0069] Then, the oil supplied to the hydraulic pressure supply section 63 of the first servo valve 31 passes through the second supply / discharge section 62 and the flow path 92b, and is supplied from the second supply / discharge port 47b of the hydraulic cylinder 30 to the second chamber 45. Also, the oil in the first chamber 44 of the hydraulic cylinder 30 is discharged from the first supply / discharge port 46a through the flow path 91a to the first supply / discharge section 61 of the first servo valve 31, and is then discharged to the first hydraulic pressure discharge section 64. Similarly, in the second servo valve 32, the oil supplied to the hydraulic pressure supply section 83 passes through the second supply / discharge section 82 and the flow path 92a, and is supplied from the second supply / discharge port 47a of the hydraulic cylinder 30 to the second chamber 45. Also, the oil in the first chamber 44 of the hydraulic cylinder 30 is discharged from the first supply / discharge port 46b through the flow path 91b to the first supply / discharge section 81 of the second servo valve 32, and is then discharged to the first hydraulic pressure discharge section 84. As a result, a large amount of oil is supplied to and discharged from the first chamber 44 and the second chamber 45 of the hydraulic cylinder 30, the piston 42 is quickly pushed leftward in FIG. 8, and the rod 43 is quickly contracted.

[0070] [Effects of this embodiment] The cylinder drive system of the first aspect comprises a hydraulic cylinder (fluid cylinder device) 30 in which the inside of the cylinder 41 is divided into a first chamber 44 and a second chamber 45 by a piston 42, and a rod 43 connected to the piston 42 passes through the second chamber 45 and extends to the outside, a first servo valve (first flow rate control device) 31 that can adjust a first supply / discharge rate of oil (fluid) to the first chamber 44, a second servo valve (second flow rate control device) 32 that can adjust a second supply / discharge rate of oil (fluid) to the second chamber 45, and a control device 33 that controls the first servo valve 31 and the second servo valve 32 so that the first supply / discharge rate and the second supply / discharge rate differ depending on the pressure-receiving area ratio of the first chamber 44 and the second chamber 45.

[0071] According to the cylinder drive system of the first aspect, the hydraulic cylinder 30 supplies and discharges the first supply / discharge amount and the second supply / discharge amount to and from the first chamber 44 and the second chamber 45 in accordance with the pressure-receiving area ratio, so that the pressure acting on the piston 42 from the first chamber 44 and the pressure acting on the piston 42 from the second chamber 45 become equal, thereby reducing pressure fluctuations in the first chamber 44 or the second chamber 45. As a result, it is possible to suppress discontinuous changes in hydraulic pressure in the hydraulic cylinder 30 when the movement direction of the rod 43 switches, and the system can be applied to various types of hydraulic cylinders 30, preventing a decrease in versatility.

[0072] In the cylinder drive system according to the second aspect, the control device 33 sets the first supply / discharge amount according to the target supply / discharge amount, and sets the second supply / discharge amount according to the first supply / discharge amount. This makes it possible to set the second supply / discharge amount to an appropriate value for the first supply / discharge amount, which is the target supply / discharge amount.

[0073] In the cylinder drive system according to the third aspect, the control device 33 sets the second discharge amount as the second supply / discharge amount to be less than the first supply amount as the first supply / discharge amount when the rod 43 of the hydraulic cylinder 30 extends. This makes it possible to effectively reduce discontinuous changes in hydraulic pressure when the rod 43 of the hydraulic cylinder 30 extends.

[0074] In the cylinder drive system according to the fourth aspect, the control device 33 sets the second supply amount as the second supply / discharge amount to be less than the first discharge amount as the first supply / discharge amount when the rod 43 of the hydraulic cylinder 30 is retracted. This makes it possible to effectively reduce discontinuous changes in hydraulic pressure when the rod 43 of the hydraulic cylinder 30 is retracted.

[0075] The cylinder drive system according to the fifth aspect is provided with a detector (drive amount detector) 48 that detects the drive amount of the hydraulic cylinder 30, and the control device 33 corrects the first supply / discharge amount and the second supply / discharge amount based on the detection result of the detector 48. This makes it possible to set the first supply / discharge amount and the second supply / discharge amount to appropriate values.

[0076] In the cylinder drive system according to the sixth aspect, the first servo valve 31 and the second servo valve 32 are a first spool valve and a second spool valve, the first supply / discharge portion 61 of the first servo valve 31 is connected to the first chamber 44, the second supply / discharge portion 62 is closed, the first supply / discharge portion 81 of the second servo valve 32 is closed, and the second supply / discharge portion 82 is connected to the second chamber 45. By making the first servo valve 31 and the second servo valve 32 spool valves, the structure can be simplified, and by individually controlling the first servo valve 31 and the second servo valve 32, the first supply / discharge amount and the second supply / discharge amount can be set to optimal values.

[0077] In the cylinder drive system according to the seventh aspect, the first servo valve 31 and the second servo valve 32 are a first spool valve and a second spool valve, the first supply and discharge portion 61 of the first servo valve 31 is connected to the first chamber 44, the second supply and discharge portion 62 is connected to the second chamber 45 via the second shut-off valve 132, the first supply and discharge portion 81 of the second servo valve 32 is connected to the first chamber 44 via the first shut-off valve 131, and the second supply and discharge portion 82 is connected to the second chamber 45. By making the first servo valve 31 and the second servo valve 32 spool valves, the structure can be simplified, and by opening the first shut-off valve 131 and the second shut-off valve 132, a large volume of oil can be supplied to and discharged from the hydraulic cylinder 30, improving operability.

[0078] The cylinder drive system according to the eighth aspect employs the first servo valve 31 and the second servo valve 32. This makes it possible to appropriately apply the first supply / discharge amount and the second supply / discharge amount to the hydraulic cylinder.

[0079] The vibration testing apparatus according to the ninth aspect includes a base unit 11, a vibration table 12 movably supported on the base unit 11, and a cylinder drive system 13 supported by the base unit 11 and having a rod 43 with its tip connected to the vibration table 12. This makes it possible for the cylinder drive system 13 to suppress discontinuous changes in hydraulic pressure in the hydraulic cylinder 30 when the movement direction of the rod 43 switches, and the vibration table 12 is moved back and forth stably, thereby improving the accuracy of the vibration test.

[0080] In the above-described embodiment, the first flow control device and the second flow control device are described as being applied to a servo valve or a spool valve, but the present invention is not limited to this configuration. Flow control valves, hydraulic pumps, etc. may also be applied as the first flow control device and the second flow control device. Furthermore, although a hydraulic cylinder is used as the fluid cylinder device, an air cylinder, etc. may also be applied. Furthermore, although the cylinder drive system is applied to a vibration testing device, it may also be applied to a single device that operates using the driving force of a fluid cylinder. [Explanation of symbols]

[0081] 10 Vibration test equipment 11 Base 12 Shaking table 13 Cylinder drive system 30 Hydraulic cylinder (fluid cylinder device) 31 First servo valve (first flow control device) 32 Second servo valve (second flow control device) 33 Control device 34 Hydraulic pump 41 cylinders 42 Piston 43 Rod 44 Room 1 45 Room 2 46, 46a, 46b First supply / discharge port 47, 47a, 47b Second supply / discharge port 48 Detector (drive amount detector) 51,71 cases 52,72 spool 53,73 Drive unit 61,81 1st supply / discharge section 62,82 2nd supply / discharge section 63,83 Hydraulic supply unit 64,84 First hydraulic discharge section 65,85 Second hydraulic discharge 66,86 First valve body 67,87 Second valve body 68,88 Third valve body 91, 91a, 91b, 92, 92a, 92b, 101, 102, 103, 106, 107, 108, 109 Flow path 104 Tank 105 Relief valve 110 Processing section 111 Branch 112 Comparison section 113 Amplification section 114 Branch 115a,115b Storage section 116a,116b Calculation part 117 Addition section 118 Comparison Section 119 Amplification Unit 120 Branch 200 Vibration target

Claims

1. a fluid cylinder device in which the inside of a cylinder is divided into a first chamber and a second chamber by a piston, and a rod connected to the piston passes through the second chamber and extends to the outside; a first flow rate control device capable of adjusting a first supply / discharge rate of fluid to / from the first chamber; a second flow rate control device capable of adjusting a second supply / discharge rate of fluid to / from the second chamber; a control device that controls the first flow rate control device and the second flow rate control device so that the first supply / discharge amount and the second supply / discharge amount differ depending on a pressure-receiving area ratio between the first chamber and the second chamber; Equipped with The first flow control device and the second flow control device are a first spool valve and a second spool valve, and the first spool valve has a first supply / discharge part connected to the first chamber and a second supply / discharge part connected to the second chamber via a shut-off valve, and the second spool valve has a first supply / discharge part connected to the first chamber via a shut-off valve and a second supply / discharge part connected to the second chamber. Cylinder drive system.

2. the control device sets the first supply / discharge amount in accordance with a target supply / discharge amount, and sets the second supply / discharge amount in accordance with the first supply / discharge amount. The cylinder drive system according to claim 1 .

3. When the rod is extended, the control device sets a second discharge amount as the second supply / discharge amount to be less than a first supply amount as the first supply / discharge amount. The cylinder drive system according to claim 2 .

4. the control device sets a second supply amount as the second supply / discharge amount to be less than a first discharge amount as the first supply / discharge amount when the rod is contracted. The cylinder drive system according to claim 2 or 3.

5. a drive amount detection unit that detects a drive amount of the fluid cylinder device is provided, and the control device corrects the first supply / discharge amount and the second supply / discharge amount based on a detection result of the drive amount detection unit. The cylinder drive system according to any one of claims 1 to 4.

6. the first spool valve and the second spool valve are servo valves. The cylinder drive system according to any one of claims 1 to 5.

7. A base portion and a vibration table movably supported on the base portion; The cylinder drive system according to any one of claims 1 to 6, wherein the rod is supported by the base portion and a tip end of the rod is connected to the vibration table; A vibration test device comprising:

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