Surge tank

Abstract

To provide a surge tank which is suitably applicable to high-pressure and high-temperature hydraulic circuit.SOLUTION: There are formed in a housing 12, an inflow port 18 through which hydraulic oil flows in and an outflow port 19 through which the hydraulic oil flows out. A bottomed cylindrical member 20 is connected to the inflow port 18. There are formed in the cylindrical member 20, first throttle holes 21A to 21D which connect the inside and outside of the cylindrical member 20 and throttle the flowing hydraulic oil. An internal space K for housing the cylindrical member 20 is formed inside the housing 12. A partition member 22 is provided which divides the internal space K into a first internal space K1 and a second internal space K2, and in the partition member 22, second throttle holes 24A, 24B are bored which connect the first internal space K1 and the second internal space K2 and throttle the flowing hydraulic oil. The inflow port 18 and the outflow port 19 communicate with each other via the inside of the cylindrical member 20, the first throttle holes 21A to 21D, the first internal space K1, the second throttle holes 24A, 24B, and the second internal space K2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a surge tank that is disposed in a hydraulic circuit to dampen pressure pulsations in the hydraulic circuit. [Background technology]

[0002] This type of surge tank has a housing attached to the hydraulic circuit, a highly elastic rubber tube attached to the housing, and the inside of the housing is divided into a central oil chamber and an outer gas chamber, with hydraulic oil from the hydraulic circuit flowing into the oil chamber and hydraulic oil from the oil chamber flowing out to the hydraulic circuit, and inert gas being injected into the gas chamber.When there is a pressure fluctuation in the hydraulic circuit, the pressure fluctuation of the hydraulic oil that has entered the oil chamber from the hydraulic circuit is transmitted to the rubber tube, and the compressibility of the gas sealed in the gas chamber absorbs the pressure fluctuation, thereby damping the pressure pulsation of the hydraulic circuit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-58302 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such conventional surge tanks, the oil chamber and gas chamber are separated by a rubber tube, which makes it difficult to use the rubber tube at high pressure or high temperature, making it difficult to apply the surge tank to high-pressure or high-temperature hydraulic circuits.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a surge tank which can be suitably applied to a high-pressure and high-temperature hydraulic circuit. [Means for solving the problem]

[0006] In order to achieve this object, the present invention takes the following measures: This surge tank is to be placed in a hydraulic circuit and comprises: a housing to be attached to a pipeline of the hydraulic circuit; an inlet formed in the housing to allow hydraulic oil from the hydraulic circuit to flow into the inside of the housing; an outlet formed in the housing to allow the hydraulic oil inside the housing to flow out to the hydraulic circuit; a cylindrical member with a bottom that is connected to the inlet; a first throttling hole drilled in the cylindrical member to connect the inside and outside of the cylindrical member and throttle the hydraulic oil flowing; an internal space formed inside the housing to accommodate the cylindrical member; a partition member that divides the internal space into a first internal space and a second internal space; and a second throttling hole drilled in the partition member to connect the first internal space and the second internal space and throttle the hydraulic oil flowing, and the inlet and outlet are connected via the inside of the cylindrical member, the first throttling hole, the first internal space, the second throttling hole, and the second internal space.

[0007] In this case, the cylindrical member may be formed with an expanding portion that gradually expands in diameter from the connection side of the inlet toward the drilling side of the first throttle hole. Also, the partition member may be inserted through the cylindrical member at the radial center, and the second throttle hole may be drilled radially outward of the cylindrical member. Effect of the Invention

[0008] As described above in detail, the invention described in claim 1 communicates between the inlet and the outlet through the inside of the cylindrical member, the first throttle hole, the first internal space, the second throttle hole, and the second internal space. Therefore, the housing, which is in contact with the hydraulic oil flowing from the inlet to the outlet, the cylindrical member having the first throttle hole, and the partition member having the second throttle hole can all be made of rigid metal material, so that there is no need to use a rubber tube as in the conventional surge tank, and the invention can be suitably applied to high pressure and high temperature hydraulic circuits. In addition, since the housing, the cylindrical member, and the partition member can all be made of rigid metal material, durability can be improved compared to the conventional surge tank using a rubber tube.

[0009] In the invention described in claim 2, the cylindrical member is formed with an expanded diameter section that gradually expands in diameter from the connection side of the inlet toward the drilling side of the first throttle hole. Therefore, the hydraulic oil that flows into the cylindrical member from the inlet is expanded by the expanded diameter section and throttled by the first throttle hole, so that pressure pulsation can be further attenuated.

[0010] In the invention described in claim 3, the partition member has a cylindrical member inserted through it at the radial center, and a second throttling hole is drilled radially outward of the cylindrical member. Therefore, by inserting the partition member into the cylindrical member, the internal space can be divided into a first internal space and a second internal space, and the first internal space and the second internal space can be connected by the second throttling hole, so that the surge tank can be easily manufactured. [Brief description of the drawings]

[0011] [Figure 1] 1 is a hydraulic circuit diagram in which a surge tank according to an embodiment of the present invention is arranged. FIG. [Diagram 2] FIG. 2 is a vertical cross-sectional view of the surge tank of the embodiment. [Diagram 3] FIG. 3 is an enlarged cross-sectional view taken along line AA in FIG. 2. [Figure 4] FIG. 3 is an enlarged cross-sectional view taken along line BB in FIG. 2. [Diagram 5] FIG. 3 is a cross-sectional view taken along line CC in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a hydraulic circuit in which a surge tank 1 according to one embodiment is arranged. The surge tank 1 is disposed in a supply flow passage 4 connecting a hydraulic pump 2 and an electromagnetic switching valve 3, and damps pressure pulsation of hydraulic oil discharged from the hydraulic pump 2. The hydraulic pump 2 is a variable displacement type that can freely change the discharge amount, and is driven by a motor 5 to draw hydraulic oil stored in a tank T from a suction flow passage 6 and discharge it to the supply flow passage 4. The electromagnetic switching valve 3 is a 4-port 3-position directional control valve that has a neutral position X, a first switching position Y, and a second switching position Z. In the neutral position X, the supply flow passage 4 is connected to a discharge flow passage 7 that connects to the tank T, and two load flow passages A and B that are connected to an actuator (not shown) are blocked. In the first switching position Y, the load flow passage A is switched to be connected to the supply flow passage 4, and the load flow passage B is switched to be connected to the discharge flow passage 7. In the second switching position Z, the load flow passage A is switched to be connected to the discharge flow passage 7, and the load flow passage B is switched to be connected to the supply flow passage 4.

[0013] Reference numeral 8 is a filter with a bypass valve that captures contaminants in the hydraulic oil and is disposed in the suction flow path 6. Reference numeral 9 is a relief valve that controls the pressure in the supply flow path 4 to a set pressure and is branched off and connected to the supply flow path 4. Reference numeral 10 is a pressure gauge that displays the pressure in the supply flow path 4. Reference numeral 11 is a check valve disposed in the supply flow path 4 which allows the flow of hydraulic oil from the hydraulic pump 2 side to the solenoid switching valve 3 side and prevents the flow of hydraulic oil from the solenoid switching valve 3 side to the hydraulic pump 2 side.

[0014] As shown in Fig. 2, 12 denotes the housing of the surge tank 1, which is formed by closing the openings at both ends of a cylindrical main body member 13 with a first cover member 14 and a second cover member 15, forming an internal space K inside. The main body member 13, the first cover member 14, and the second cover member 15 are each fixed by welding and made of a rigid metal material. 16 denotes a block member made of a rigid metal material and formed into a substantially rectangular parallelepiped shape, with its underside abutting against the upper surface of the first cover member 14 and removably attached with a plurality of bolt members 17, forming a part of the housing 12. 18 denotes an inlet through which the hydraulic oil of the hydraulic circuit flows into the housing 12, and 19 denotes an outlet through which the hydraulic oil inside the housing 12 flows out to the hydraulic circuit, both of which are drilled into the block member 16. As shown in FIG. 1, the inlet 18 is connected to the hydraulic pump 2 side of the supply passage 4 , and the outlet 19 is connected to the solenoid switching valve 3 side of the supply passage 4 , with each end opening to the lower surface of the block member 16 .

[0015] Reference numeral 20 denotes a cylindrical member made of a rigid metal material and formed into a cylindrical shape with a bottom, which is attached to and hangs down from the end of the inlet 18 opening on the lower surface of the block member 16, and is accommodated in the internal space K. As shown in Figs. 3 and 4, reference numerals 21A, 21B, 21C, and 21D denote four first throttle holes, which are drilled in the cylindrical member 20 to connect the inside and outside of the cylindrical member 20 and throttle the flowing hydraulic oil. Two first throttle holes 21A and 21B are formed penetrating the cylindrical member 20 in a direction parallel to the paper surface of Fig. 2. The remaining two first throttle holes 21C and 21D are formed penetrating the cylindrical member 20 in a direction perpendicular to the two first throttle holes 21A and 21B at a position lower in Fig. 2 than the two first throttle holes 21A and 21B. The tubular member 20 forms an expanded diameter section 20A at a position above the axial middle position in Figure 2, and the expanded diameter section 20A gradually expands in diameter from the connection side of the inlet 18 toward the drilling side of the first throttling holes 21A-21D, increasing the volume inside the tubular member 20.

[0016] As shown in Fig. 5, 22 is a partition member formed in a disk shape from a rigid metal material, which has an insertion hole 23 formed in the radial center through which the cylindrical member 20 is inserted with a gap, and its outer peripheral surface is fixed by welding to the inner peripheral surface of the main body member 13 constituting the housing 12, dividing the internal space K into a first internal space K1 located at the lower part in Fig. 2 and a second internal space K2 located at the upper part. 24A, 24B, 24C, and 24D are four second throttling holes which are bored in the partition member 22 at equal intervals in the circumferential direction radially outward of the insertion hole 23 to connect between the first internal space K1 and the second internal space K2 and throttle the flowing hydraulic oil.

[0017] Reference numeral 25 denotes a through hole formed in the radial center of the first cover member 14 in the vertical direction in FIG. 2, with an upper opening closed by the block member 16 and a lower opening connecting to the second internal space K2, through which the base portion of the cylindrical member 20 hanging down from the block member 16 is inserted with a gap. Reference numeral 26 denotes a communication hole formed in the first cover member 14 in the vertical direction at a position radially spaced from the through hole 25, and connecting between the second internal space K2 and the outlet 19. The inlet 18 and the outlet 19 communicate with each other via the inside of the cylindrical member 20, the first throttle holes 21A-21D, the first internal space K1, the second throttle holes 24A-24D, the gap between the cylindrical member 20 and the insertion hole 23, the second internal space K2, and the communication hole 26.

[0018] 2 at the radial center of the second cover member 15. It is blocked with a plug member 28, and during maintenance and inspection, the plug member 28 is removed to drain the hydraulic oil in the internal space K. The air vent hole 29 is drilled in the block member 16. It is connected to the outlet 19 and has one end open on the upper surface of the block member 16. When the surge tank 1 is first placed in the hydraulic circuit, the air inside is discharged through this hole, and it is thereafter blocked with a plug member 30.

[0019] Next, the operation of this configuration will be described. In the state shown in Figure 1, when the hydraulic pump 2 is rotationally driven by the motor 5, the hydraulic pump 2 draws in the hydraulic oil stored in the tank T through the suction passage 6 and discharges it to the supply passage 4. The hydraulic oil discharged to the supply passage 4 flows through the check valve 11 and the surge tank 1 to the solenoid switching valve 3. The solenoid switching valve 3 is located in the neutral position X, and the hydraulic oil flowing through the supply passage 4 flows through the discharge passage 7 and returns to the tank T.

[0020] In this state, when the solenoid switching valve 3 is switched to the first switching position Y, the hydraulic oil in the supply flow path 4 flows through the load flow path A and is supplied to the actuator (not shown), and the hydraulic oil from the actuator flows through the load flow path B and the discharge flow path 7 and is discharged to the tank T, and the actuator operates in one direction. Then, when the solenoid switching valve 3 is returned to the neutral position X, the actuator stops.

[0021] In this state, when the solenoid switching valve 3 is switched to the second switching position Z, the hydraulic oil in the supply flow path 4 flows through the load flow path B and is supplied to the actuator (not shown), and the hydraulic oil from the actuator flows through the load flow path A and the discharge flow path 7 and is discharged to the tank T, and the actuator operates in the other direction. Then, when the solenoid switching valve 3 is returned to the neutral position X, the actuator stops.

[0022] 2, the hydraulic oil flowing through the supply flow passage 4 flows from the inlet 18 of the surge tank 1 inside the cylindrical member 20, is expanded by the enlarged diameter section 20A, is throttled by the first throttle holes 21A-21D, is expanded in the first internal space K1, is throttled by the second throttle holes 24A-24D (a part of the hydraulic oil is throttled in the gap between the cylindrical member 20 and the insertion hole 23), is expanded in the second internal space K2, and flows out from the outlet 19. The hydraulic oil is expanded and throttled multiple times inside the surge tank 1, thereby damping the pressure pulsation.

[0023] In this operation, the surge tank 1 communicates between the inlet 18 and the outlet 19 through the inside of the cylindrical member 20, the first throttle holes 21A-21D, the first internal space K1, the second throttle holes 24A-24D, and the second internal space K2. Therefore, the housing 12, which is in contact with the hydraulic oil flowing from the inlet 18 to the outlet 19, the cylindrical member 20 having the first throttle holes 21A-21D formed therein, and the partition member 22 having the second throttle holes 24A-24D formed therein, can all be made of rigid metal materials, so that rubber tubes are not required as in conventional surge tanks, and the surge tank 1 can be suitably applied to high-pressure and high-temperature hydraulic circuits. In addition, since the housing 12, the cylindrical member 20, and the partition member 22 can all be made of rigid metal materials, durability can be improved compared to conventional surge tanks that use rubber tubes.

[0024] Further, the cylindrical member 20 is formed with an expanded diameter section 20A that gradually expands in diameter from the connection side of the inlet 18 toward the drilling side of the first throttling holes 21A-21D. Therefore, the hydraulic oil that flows into the inside of the cylindrical member 20 from the inlet 18 is expanded by the expanded diameter section 20A and throttled by the first throttling holes 21A-21D, so that the pressure pulsation can be further attenuated.

[0025] Furthermore, the partition member 22 has the cylindrical member 20 inserted through it at the radial center, and the second throttling holes 24A-24D are drilled radially outward of the cylindrical member 20. Therefore, by inserting the partition member 22 into the cylindrical member 20, the internal space K can be divided into a first internal space K1 and a second internal space K2, and the first internal space K1 and the second internal space K2 can be connected by the second throttling holes 24A-24D, so that the surge tank 1 can be manufactured easily.

[0026] In the above embodiment, the housing 12 is configured by closing both end openings of the cylindrical main body member 13 with the first cover member 14 and the second cover member 15, but the housing may be configured with a bottomed main body member forming an opening at one end and a cover member closing the one end opening of the main body member. Also, the first cover member 14 and the block member 16 are provided separately, but the block member may be formed integrally with the first cover member. Furthermore, while the first throttle holes 21A-21D and the second throttle holes 24A-24D are provided in four pieces each, the number is not limited to four, and it goes without saying that the number may be three or less, or five or more. [Explanation of symbols]

[0027] 1: Surge tank 12: Housing 18:Inlet 19: Outlet 20: Cylindrical member 21A, 21B, 21C, 21D: First aperture 22: Partition material 24A, 24B, 24C, 24D: Second throttle hole K:Inner space K1: 1st internal space K2: 2nd internal space

Claims

1. a first throttling hole formed in the cylindrical member to connect the inside and outside of the cylindrical member and to throttle the hydraulic oil flowing therethrough; an internal space formed inside the housing to accommodate the cylindrical member; a partition member dividing the internal space into a first internal space and a second internal space; and a second throttling hole formed in the partition member to connect the first internal space and the second internal space and to throttle the hydraulic oil flowing therethrough. The surge tank is characterized in that the inlet and the outlet are connected via the inside of the cylindrical member, the first throttling hole, the first internal space, the second throttling hole, and the second internal space.

2. 2. The surge tank according to claim 1, wherein the cylindrical member is formed with an expanded diameter portion that is gradually expanded in diameter from a connection side of the inlet toward a drilling side of the first throttle hole.

3. 3. The surge tank according to claim 1, wherein the partition member has a radial center through which the cylindrical member is inserted, and the second throttling hole is formed radially outward of the cylindrical member.

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