JP2021001655A - Hydraulic booster device - Google Patents

Abstract

To provide a hydraulic booster device having a quiet, small and light structure.SOLUTION: A hydraulic booster device 1 includes: a hydraulic cylinder 4 having a changeover valve part 2 and a pressure boost part 3; a direction control part 7 having a first solenoid valve 5 and a direction switching valve 6; a pressure switch 8; and a manifold part 10 having a high pressure relief valve 9. The hydraulic booster device is configured such that: working fluid is fed from a pump P; the working fluid boosted in pressure by the hydraulic cylinder 4 is supplied to a hydraulic tool U; the high pressure relief valve 9 is operated and the pressure switch 8 is operated when the pressure of the working fluid reaches predetermined high pressure; and the working fluid supplied to the hydraulic tool U is discharged to a tank T. The hydraulic cylinder 4 is configured to operate a piston 3b built in a cylinder chamber 3a of the pressure boost part 3 by operating a first spool 2b built in a body 2a of the changeover valve part 2. The structures of the changeover valve part 2 and the pressure boost part 3 are connected or integrated, and the first spool 2b and the piston 3b are juxtaposed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hydraulic booster device for operating a hydraulic tool.

Conventionally, by moving the shuttle ball of the shuttle valve to the left and right with the direction switching part on the pump side, the hydraulic oil from the pump is sent to the hydraulic cylinder to operate the piston to increase the pressure, and the increased hydraulic oil is applied. When a hydraulic tool such as a clamp tool is operated by supplying it to a single-acting cylinder and the gripping force of the hydraulic tool reaches a predetermined high pressure, the relief valve is opened and the pressure switch is operated to move the direction switching portion to the tank side. Further, there is known a hydraulic booster device having a configuration in which hydraulic oil supplied to the single-acting cylinder is discharged from a drain and the hydraulic tool is released by a return spring (Patent Document 1: Patent No. 3579546).

The hydraulic booster device is mounted on a work vehicle equipped with a hydraulic tool such as a clamp tool, and the device is required to be smaller and lighter. In addition, work vehicles often work in residential areas, and the operating noise generated when the hydraulic booster device operates becomes noise, so it is necessary to suppress the operating noise of the device as much as possible.

Japanese Patent No. 3579546

As a known technique as described in Patent Document 1, a hydraulic booster device having a structure in which a mechanical mechanism such as a detent is combined with a piston is known. Since such a mechanical mechanism has a large size and mass, the conventional structure has a problem that the size of the pressure boosting portion becomes large and the mass becomes large. Further, mechanical mechanisms such as detents frequently generate collision noise due to collision of metal parts, which contributes to noise. The shuttle ball also has the same problem.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flood control booster device that is quiet and has a compact and lightweight structure.

As an embodiment, the problem is solved by a solution means as disclosed below.

The hydraulic booster device according to the present invention has a hydraulic cylinder having a switching valve portion and a pressure boosting portion, a direction control unit having a first solenoid valve and a direction switching valve, a pressure switch, and a manifold portion having a high pressure relief valve. When the hydraulic oil supplied from the pump is sent, the hydraulic oil boosted by the hydraulic cylinder is supplied to the hydraulic tool, and then the hydraulic oil supplied to the hydraulic tool reaches a predetermined high pressure, the high pressure is provided. The relief valve operates, the pressure switch operates, and the hydraulic oil supplied to the hydraulic tool is discharged to the tank, and the hydraulic cylinder operates the first spool built in the body of the switching valve portion. As a result, the piston built in the cylinder chamber of the pressure booster is operated, and the direction control unit is configured to operate the second spool built in the body of the direction switching valve by the first solenoid valve. A pump connecting solenoid valve that operates the hydraulic oil from the pump so that the hydraulic oil can be sent and a tank connecting solenoid valve that operates the hydraulic oil so that the hydraulic oil can be discharged to the tank are arranged on the body of the first solenoid valve. The configuration is such that the switching valve portion and the pressure boosting portion have a connected structure or an integrated structure, and the first spool and the piston are arranged side by side. It is characterized by.

According to this configuration, a mechanical mechanism such as a detent and a shuttle ball are eliminated, and a spool-type switching valve is adopted, so that a quiet, compact and lightweight structure can be achieved. Moreover, since the hydraulic cylinder has a structure in which the first spool and the piston are arranged side by side, the structure can be further reduced in size and weight.

The cylinder chamber preferably has a plasma nitriding layer formed in a range in contact with the piston. According to this configuration, the area in contact with the piston is made high strength by the plasma nitriding treatment layer to improve the wear resistance, so that the operation is stable for a long period of time and a highly accurate dimensional shape can be secured. Further, as an example, it is possible to prevent an increase in the amount of auction of the ram in the hydraulic tool due to a hydraulic oil leak from the piston.

As an example, a check valve such as a switching check and a speed adjusting valve are attached to the cylinder body constituting the cylinder chamber. Especially for parts such as check valves and speed control valves that want to reduce leaks, it is necessary to adapt the shape of the parts to the processed shape of the cylinder body to prevent leaks of hydraulic oil and the like. Therefore, there is a method of performing a work of rubbing the shapes at the time of assembling, so-called “hit”. On the other hand, since the range in which the plasma nitriding treatment layer is formed has high hardness, deformation due to so-called “hit” is reduced, so that leakage of hydraulic oil or the like may not be sufficiently prevented. For this reason, it is preferable that the plasma nitriding treatment layer is not formed at the portion where the so-called “hit” is performed. That is, as an example, the area of the cylinder body in contact with the check valve and the speed adjusting valve is not subjected to plasma nitriding treatment.

It is preferable that the first port connected to the pump and the second port connected to the tank are provided in the manifold portion, and the manifold portion and the hydraulic cylinder have a connected structure or an integral structure. According to this configuration, it is possible to make the structure smaller and lighter while suppressing the power transmission loss.

The high-pressure relief valve is preferably configured to operate when the needle valve built into the body separates from the valve body, and a step that regulates the operating range of the needle valve is formed on the inner wall of the body. According to this configuration, when the hydraulic oil reaches a predetermined high pressure (first pressure value) and the needle valve separates from the valve body, the rear end of the flange formed on the needle valve is formed on the inner wall of the body. Since it is in contact with the needle valve, the rear end (the end opposite to the valve body) does not go to the depth of the counterbore formed in the adjusting screw, and the collision between the needle valve and the adjusting screw can be avoided, so that the collision noise is generated. It can be a lost silent structure.

As an example, the body of the needle valve is formed with the step at a position that restricts the stroke of the needle valve to 1 [mm] or less and allows opening and closing operations. According to this configuration, it is possible to reduce the impact when the rear end of the flange of the needle valve comes into contact with the step, further suppress noise, and make the structure even smaller and lighter. As an example, the step is formed at a position that regulates the stroke of the needle valve to 0.3 [mm] or more and 1 [mm] or less.

The high-pressure relief valve preferably has a plurality of through holes in the body through which hydraulic oil can be discharged. According to this configuration, the high-pressure relief valve operates, and when the high-pressure hydraulic oil is discharged to the drain, a sudden pressure difference (for example, 50 to 90 [MPa]] when the hydraulic oil in the body is discharged to the drain. ) Can suppress abnormal noise. Abnormal noise is a kind of fluid sound, and is exemplified by "shoe sound", "beep sound", "whistle sound" and the like. As an example, the through hole is formed at a position line-symmetrical with respect to the axial center line of the body, or a spring arranged between the flange formed on the needle valve and the adjusting screw. It is formed at a position that is line-symmetrical with respect to the center line of. As an example, in the body, a plurality of through holes communicating with the drain are formed at predetermined intervals in a section between the front end of the flange of the needle valve and the valve body. As an example, the inner diameter of the through hole is set to 0.02 times or more and 0.25 times or less the inner diameter of the valve body.

As an example, the first solenoid valve is operated by the first command from the controller to send the hydraulic oil from the pump, and the piston is moved so that the hydraulic oil supplied to the hydraulic tool reaches the first pressure value. It is a configuration to operate. According to this configuration, the pressure of the hydraulic tool can be easily controlled.

As an example, a low-pressure relief portion having a second solenoid valve and a low-pressure relief valve is further provided.
The second electromagnetic valve is operated by the second command from the controller to connect the hydraulic tool and the low pressure relief valve, and the hydraulic oil from the pump is supplied to the hydraulic tool without operating the piston. When the hydraulic tool is operated and the hydraulic oil supplied to the hydraulic tool reaches the second pressure value, the low pressure relief valve is operated, and then the hydraulic tool and the low pressure relief valve are disconnected. Is. According to this configuration, a high-pressure relief valve that operates when the hydraulic oil reaches the first pressure value (predetermined high pressure) and a low-pressure relief valve that operates when the hydraulic oil reaches the second pressure value (predetermined low pressure). Depending on the combination, a hydraulic tool can be made to perform complicated and highly flexible movements. Further, according to this configuration, the hydraulic cylinder can be stopped and the hydraulic tool can be operated within the range that can be operated with the low-pressure hydraulic oil, so that the power saving operation can be performed and the series of operations is further quiet. Can be achieved.

Examples of the hydraulic tool include a crimping tool, a compression tool, a caulking tool, a fastening tool, a clamp tool, a cutting tool, and other known hydraulic tools. As an example, a hydraulic tool is a tool for electrical installation work. It also has a function (grip operation) of caulking, compressing, or crimping a high-voltage electric wire, a sleeve for connecting an electric wire, a terminal, or the like within a pressure range including a predetermined high pressure (first pressure value). In addition, it may have a function (temporary gripping operation) of sandwiching a high-voltage electric wire, a sleeve for connecting an electric wire, a terminal, or the like within a pressure range including a predetermined low voltage (second pressure value).

As an example, the pressure switch has a configuration in which a micro switch built in a case is operated by a poppet, and the direction control unit and the pressure switch are externally attached to the manifold unit, respectively. According to this configuration, noise reduction can be achieved, and the entire device can be made into a compact and lightweight structure.

According to the present invention, a quiet, compact and lightweight structure can be achieved by eliminating a mechanical mechanism such as a detent and a shuttle ball and adopting a spool-type switching valve. Further, since the hydraulic cylinder has a structure in which the first spool and the piston are arranged side by side, a hydraulic booster device having a smaller and lighter structure can be realized.

FIG. 1 is a schematic view showing a hydraulic booster device according to an embodiment of the present invention, and is a perspective view of the front side viewed from diagonally above. FIG. 2 is a perspective view of the back side of FIG. 1 as viewed from diagonally above. FIG. 3 is a perspective view of FIG. 1 rotated 180 ° around the Z axis and viewed from diagonally above. FIG. 4 is a perspective view of the front side of FIG. 1 as viewed from diagonally above. 5A to 5C are schematic cross-sectional views showing the structure of the hydraulic cylinder according to the present embodiment, FIG. 5A is a schematic cross-sectional view seen from the plane side, and FIG. 5B is a schematic cross-sectional view seen from the front side. It is a cross-sectional view, and FIG. 5C is a schematic cross-sectional view seen from the side surface side. FIG. 6A is a schematic cross-sectional view of FIG. 5A at the time of pressure increase when viewed from the plane side, and FIG. 6B is a schematic cross-sectional view of FIG. 5B at the time of pressure increase when viewed from the front side. 7A to 7C are schematic cross-sectional views showing the structure of the cylinder body according to the present embodiment, FIG. 7A is a schematic cross-sectional view showing the range in which the plasma nitriding treatment layer is formed, and FIG. 7B is a schematic cross-sectional view. FIG. 7C is a schematic cross-sectional view showing a range in which the plasma nitriding treatment layer is not formed, and FIG. 7C is a schematic cross-sectional view showing a range in which the plasma nitriding treatment layer is not formed. FIG. 8 is a schematic cross-sectional view showing the structure of the direction control unit according to the present embodiment. 9A is a schematic cross-sectional view showing the structure of FIG. 8 when the hydraulic oil is fed from the pump, and FIG. 9B is a schematic cross-sectional view showing the structure of FIG. 8 when the hydraulic oil is discharged to the tank. .. 10A to 10B are schematic cross-sectional views showing the structures of the manifold portion and the low pressure relief portion according to the present embodiment, and FIG. 10A is a schematic sectional view seen from the plane side so that the internal structure of the low pressure relief valve is shown. It is a cross-sectional view, and FIG. 10B is a schematic cross-sectional view seen from the plane side so that the internal structure of the pilot check valve is shown. FIG. 11 is a schematic cross-sectional view showing the structure of the manifold portion according to the present embodiment, and is a schematic cross-sectional view seen from the front side so as to show the internal structure of the high-pressure relief valve. FIG. 12 is a schematic cross-sectional view showing the structure of the pressure switch according to the present embodiment, and is a schematic cross-sectional view seen from the X direction in FIG. FIG. 13 is a schematic hydraulic circuit diagram showing the hydraulic booster device according to the present embodiment. FIG. 14 is a graph showing the operation of the hydraulic booster device in FIG. 13, and is a graph showing the relationship between the command from the controller and the time change of the pressure in the hydraulic circuit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The hydraulic booster device 1 according to the present embodiment is mounted on a work vehicle including a hydraulic tool U, a controller W, a pump P, and a tank T. In all the drawings for explaining the embodiment, members having the same function may be designated by the same reference numerals, and the repeated description thereof may be omitted. Here, in order to make it easier to explain the positional relationship of each part of the hydraulic booster device 1, the directions are indicated by arrows X, Y, and Z in the drawing. When the hydraulic booster device 1 is actually used, it is not limited to these directions, and there is no problem in using it in any direction.

As an example, the hydraulic booster device 1 has a hydraulic cylinder 4 having a switching valve portion 2 and a pressure boosting portion 3, and a directional control having a first solenoid valve 5 and a direction switching valve 6, as shown in FIGS. A manifold portion 10 having a portion 7 and a pressure switch 8 and a high-pressure relief valve 9 is provided, and the constituent portions are arranged close to each other or adjacent to each other.

The manifold portion 10 has a first port (P port) 10a and a second port (T port) 10b in the body 10c. Further, the low-pressure relief portion 11 has a third port (P2 port) 11a and a fourth port (drain port) 11b in the body 11c. Here, the P port 10a and the T port 10b are arranged on the same surface, and the P2 port 11a and the drain port 11b are arranged on the same surface. As a result, the hydraulic booster device 1 can be easily connected to the pump P, the tank T, and the hydraulic tool U, and the power transmission loss can be suppressed.

5A to 5C and 6A to 6B are schematic cross-sectional views showing the structure of the hydraulic cylinder 4. The hydraulic cylinder 4 of the present embodiment has a structure in which the switching valve portion 2 and the pressure boosting portion 3 are connected to each other, and the first spool 2b and the piston 3b are arranged side by side. Here, parallel arrangement means side by side and includes parallel arrangement. The manifold portion 10 and the hydraulic cylinder 4 are connected to each other, and the direction control unit 7 and the pressure switch 8 are externally attached to the manifold portion. According to this configuration, it is possible to make the structure smaller and lighter while suppressing the power transmission loss. The configuration is not limited to the above, and the switching valve portion 2 and the pressure boosting portion 3 may have an integral structure, and the manifold portion 10 and the hydraulic cylinder 4 may have an integral structure.

When the pressure of the hydraulic cylinder 4 is increased, the first spool 2b built in the body 2a of the switching valve portion 2 is operated to enter the low pressure section 3a1 (on the right side of the piston 3b in the figure) in the cylinder chamber 3a of the pressure increasing portion 3. The hydraulic oil in the high-pressure section 3a2 (left side of the piston 3b in the figure) in the cylinder chamber 3a is increased in pressure by operating the piston 3b built in the cylinder chamber 3a to supply the hydraulic oil to the hydraulic tool U. It is a configuration to do. The piston 3b has a narrow diameter portion and an enlarged diameter portion. In the cylinder chamber 3a, the cross-sectional area of the low-pressure compartment 3a1 (cross-sectional area seen from the operating direction of the piston 3b) is set to be larger than the cross-sectional area of the high-pressure compartment 3a2 (cross-sectional area seen from the operating direction of the piston 3b). As an example, it is set to 2 times or more and 10 times or less.

According to this embodiment, by eliminating the mechanical mechanism such as the detent and the shuttle ball and adopting the spool type switching valve portion 2, a quiet, compact and lightweight structure can be obtained. Since the hydraulic cylinder 1 has a structure in which the first spool 2b and the piston 3b are arranged side by side, the structure can be further reduced in size and weight.

7A to 7C show a range K1 in which the plasma nitriding layer is formed (a range K1 shown by hatching in FIG. 7A), a range K2 and K3 in which the plasma nitriding layer is not formed, in the cylinder body 3c (FIG. 7A to 7C). 7B is a schematic cross-sectional view showing a range K2 shown by hatching and FIG. 7C shows a range K3) shown by hatching. According to the present embodiment, since the structure has improved wear resistance, the operation can be stabilized for a long period of time, and high-precision dimensions and shapes can be secured. Further, as an example, it is possible to prevent an increase in the amount of auction of the ram in the hydraulic tool U due to a hydraulic oil leak from the piston 3b. The cylinder body 3c is made of a steel material, and as an example, a special steel material such as SCM440 or a non-conditioning free-cutting material is appropriately selected.

As an example, as shown in FIG. 7A, the range K1 in which the plasma nitriding treatment layer is formed is limited to a position symmetrical with respect to the axis in the piston chamber 3a. Further, as an example, as shown in FIG. 7B, the plasma nitriding treatment is not applied to the range K2 in contact with the check valve 16 in the cylinder body 3c. Then, in the example of FIG. 7C, the plasma nitriding treatment is not applied to the range K3 in the cylinder body 3c in contact with the speed adjusting valve 14. According to this configuration, the range in contact with the piston 3b is made high in strength by the plasma nitriding treatment layer to improve the wear resistance, so that the operation is stable for a long period of time and a highly accurate dimensional shape can be secured. Further, since the plasma nitriding treatment is not applied to the range in contact with the check valve 16 and the range in contact with the speed control valve 14, it is easy to "hit" the part shape to be adapted to the processed shape of the cylinder body at the time of assembly. It can be carried out and leakage of hydraulic oil or the like can be easily prevented.

8 and 9A to 9B are schematic cross-sectional views showing the structure of the direction control unit 7. The direction control unit 7 of the present embodiment has a configuration in which a first solenoid valve 5 and a direction switching valve 6 are combined, and the first solenoid valve 5 has a tank connection solenoid valve 5a arranged on one side of the body 5c. A solenoid valve 5b for connecting a pump is arranged on the other side of the body 5c. The directional control unit 7 has a configuration in which the second spool 6b built in the body 6a of the directional control valve 6 is operated and controlled by the first solenoid valve 5. Here, in order to enable the hydraulic oil from the pump P to be fed, the tank connection solenoid valve 5a can be turned off, the pump connection solenoid valve 5b can be turned on, and the hydraulic oil can be discharged to the tank T. The pump connection solenoid valve 5b is turned off, and the tank connection solenoid valve 5a is turned on.

FIG. 8 shows a neutral state. As an example, there is a central land 6j which is a central position in the second spool 6b on the central line N1 orthogonal to the axis of the second spool 6b. As an example, the second spool 6b has a symmetrical shape with respect to the center line N1, and the first land 6k1 and the second land 6k2 are arranged symmetrically at predetermined intervals on both sides of the central land 6j. As an example, the width of the first land 6k1 and the second land 6k2 (width in the traveling direction of the second spool 6b) is set larger than the width of the central land 6j (width in the traveling direction of the second spool 6b). Not limited to the above, a known structure can be applied as the second spool.

FIG. 9A is a schematic cross-sectional view showing the structure of FIG. 8 when the hydraulic oil is fed from the pump P. When the pump P1 is operated and the pump connecting solenoid valve 5b is operated by the first command E1 from the controller W, the hydraulic oil from the pump P is discharged from the first flow path formed in the body 5c of the first solenoid valve 5. The second spool 6b is pushed from 5p1 through the second flow path 6e formed in the body 6a of the direction switching valve 6 (the second spool 6b in FIG. 9A is pushed to the left). Then, the pump P and the hydraulic cylinder 4 are circuit-connected, and the hydraulic oil from the pump P goes to the switching check valve 21 and the speed adjusting valve 14.

FIG. 9B is a schematic cross-sectional view showing the structure of FIG. 8 when the hydraulic oil is discharged to the tank T. When the hydraulic oil supplied to the hydraulic tool U reaches a predetermined high pressure, the high pressure relief valve 9 operates to operate the pressure switch 8, and then the first command E1 from the controller W is released to release the pump connection solenoid valve 5b. Is OFF (stopped state), the tank connection solenoid valve 5a is turned on by, for example, a timer operation, and the hydraulic oil from the pump P is supplied to the third flow path 5p2 formed in the body 5c of the first solenoid valve 5. The second spool 6b is pushed through the fourth flow path 6f formed in the body 6a of the direction switching valve 6 (as shown in FIG. 9B, the second spool 6b is pushed to the right). Then, the hydraulic oil can be discharged to the tank T.

In this embodiment, the flow rate of the hydraulic oil from the first flow path 5p1 is limited when the hydraulic oil from the first flow path 5p1 goes through the second flow path 6e toward the second spool 6b. Here, a counterbore is formed in the second flow path 6e, and the damper 6g1 is movably inserted into the counterbore in the flow direction of the hydraulic oil. Further, in the present embodiment, the flow rate of the hydraulic oil from the third flow path 5p2 is limited when the hydraulic oil from the third flow path 5p2 goes through the fourth flow path 6f toward the second spool 6b. is there. Here, a counterbore is formed in the fourth flow path 6f, and the damper 6g2 is movably inserted into the counterbore in the flow direction of the hydraulic oil.

The damper 6g1 and the damper 6g2 have a tubular shape made of a steel material such as S45C, and similar dampers are arranged in the second flow path 6e and the fourth flow path 6f, respectively. Here, the dampers 6g1 and the dampers 6g2 are formed with through holes 6h having a size larger than or equal to 0.5 times the size that regulates the flow rate of the hydraulic oil so that the second spool 6b can operate. According to this configuration, the operating speed of the second spool 6b can be appropriately reduced, and the structure can be made even quieter. Further, the damper 6g1 and the damper 6g2 are movably inserted in the flow direction of the hydraulic oil. That is, by gently operating the second spool 6b, it is possible to prevent the second spool 6b from suddenly operating and colliding with the stopper arranged ahead in the traveling direction to generate a loud collision sound, and the collision sound is produced. Since it can be made smaller, the structure can be made even quieter.

In the examples of FIGS. 8, 9A and 9B, a first notch 6u1 through which hydraulic oil can flow is formed at a boundary portion of the first land 6k1 near the central land 6j. Further, a second notch 6u2 through which hydraulic oil can flow is formed at a boundary portion of the second land 6k2 near the central land 6j.

According to this configuration, when the tank connection solenoid valve 5a is turned on and the second spool 6b is pushed (the second spool 6b in FIG. 9A is pushed to the left) and connected to the tank connection side, the cylinder It is possible to suppress the discharge start sound generated by a sudden pressure difference (for example, 10 to 20 [MPa]) when the hydraulic oil in the side circuit is discharged to the tank T. Then, when the pump connection solenoid valve 5b is turned on and the second spool 6b is pushed (the second spool 6b in FIG. 9B is pushed to the right) and connected to the cylinder connection side, the inside of the pump side circuit It is possible to suppress the supply start noise caused by a sudden pressure difference (for example, 10 to 20 [MPa]) when the hydraulic oil is supplied to the cylinder. The first notch 6u1 and the second notch 6u2 are sized so that hydraulic oil can flow. Further, the first notch 6u1 and the second notch 6u2 are sized so that the second spool can operate. It is possible to omit either the first notch 6u1 or the second notch 6u2.

10A to 10B are cross-sectional views showing the arrangement and structure of the manifold portion 10 and the low pressure relief portion 11. Here, the body 11c of the low-pressure relief portion 11 is externally attached to the body 10c of the manifold portion 10. FIG. 11 is a cross-sectional view showing the arrangement and structure of the manifold portion 10 and the high pressure relief valve 9. Here, the high-pressure relief valve 9 is externally attached to the body 10c of the manifold portion 10. According to this configuration, the high pressure relief valve 9 that can be operated when the hydraulic oil reaches a predetermined high pressure (first pressure value G1) and can be operated when the hydraulic oil reaches a predetermined low pressure (second pressure value G2). By combining with the low pressure relief unit 11, the hydraulic tool U can perform complicated and highly flexible operations.

The high-pressure relief valve 9 of the present embodiment has a configuration in which the needle valve 9b built in the body 9a operates away from the valve body 9f, and a step 9c that regulates the stroke of the needle valve 9b is formed on the inner wall of the body 9a. Has been done. According to this configuration, when the hydraulic oil reaches a predetermined high pressure (first pressure value G1) and the needle valve 9b separates from the valve body 9f, the rear end of the flange 9b1 formed on the needle valve 9b is the body 9a. Since it abuts on the step 9c formed on the inner wall, the rear end of the needle valve 9b (the end opposite to the valve body 9f) does not go to the depth of the counterbore formed on the adjusting screw 9g and is adjusted with the needle valve 9b. Collision with the screw 9g can be avoided. That is, since the collision with the adjusting screw 9g can be avoided, the collision noise near the surface of the body 9a can be avoided, and the operating noise of the needle valve 9b in the high-pressure relief valve 9 is easily trapped inside the body 9a. Therefore, it is possible to create a silent structure that suppresses collision noise.

As an example, the body 9a is formed with a step 9c at a position where the stroke of the needle valve 9b is 1 [mm] or less and the opening / closing operation is restricted. According to this configuration, noise can be further suppressed. As an example, the step 9c is formed at a position that regulates the stroke of the needle valve 9b to 0.3 [mm] or more and 1 [mm] or less.

In the example of FIG. 11, the body 9a is formed with a plurality of through holes 9d through which hydraulic oil can be discharged. According to this configuration, when the high-pressure relief valve 9 operates and the hydraulic oil in the body 6a is discharged to the drain when the high-pressure hydraulic oil is discharged, a sudden pressure difference (for example, 50 to 90 [for example]]. It is possible to suppress abnormal noise caused by MPa]). Abnormal noise is a kind of fluid sound, and is exemplified by "shoe sound", "beep sound", "whistle sound" and the like. Here, the through hole 9d is formed at a position that is line-symmetric with respect to the axial center line of the body 6a, or is arranged between the flange 9b1 formed on the needle valve 9b and the adjusting screw 9g. It is formed at a position that is line-symmetric with respect to the center line of the spring 9h. That is, since the needle valve operates straight along the center line, abnormal noise (fluid noise) can be suppressed more effectively. As an example, in the body 9a, a plurality of through holes 9d communicating with the drain are formed at predetermined intervals in a section from the front end of the flange 9b1 of the needle valve 9b to the valve body 9f. As an example, the number of through holes 9d is 2, 3, 4 or 5 or more. As an example, the inner diameter of the through hole 9d is set to 0.02 times or more and 0.25 times or less the inner diameter of the valve body 9f.

FIG. 12 is a schematic cross-sectional view showing the structure of the pressure switch 8. The pressure switch 8 has a configuration in which the micro switch 8b built in the tubular case 8a is operated by the poppet 8d and the poppet 8h. The microswitch 8b is arranged in the holder 8c, and the poppet 8d is assembled in the hole formed in the holder 8c, and the front end of the flange 8d1 formed in the poppet 8d and the inner recess of the holder 8c. A spring 8f is arranged over the spring 8f. According to this configuration, the poppet 8h has a contact portion with the stopper inside, so that the noise can be reduced.

Here, in the pressure switch 8, the case 8a and the holder 8c are connected and fixed by a plurality of fixing members 8g (fixing bolts and fixing screws) in a direction parallel to the axial direction of the poppet 8d and the poppet 8h. According to this configuration, the operating force generated by the operation of the poppet 8d and the poppet 8h can be stably suppressed by the fixing member 8g, so that the operation is stable for a long period of time and the structure has high operation reliability.

Subsequently, the operation procedure of the hydraulic booster device 1 will be described below.

FIG. 13 is a schematic hydraulic circuit diagram showing the hydraulic booster device 1 and the peripheral portion of the present embodiment, and the portion surrounded by the alternate long and short dash line shows the hydraulic booster device 1. The example of FIG. 13 is a hydraulic booster device 1 having a temporary gripping function. FIG. 14 is a graph showing the operation of the hydraulic booster device 1, and is a graph showing the relationship between the command from the controller W and the time change of the pressure in the hydraulic circuit.

As an example, the second solenoid valve 12 is turned on by the second command E2 (for example, energization or sending an ON signal) from the controller W to operate the input side of the hydraulic tool U and the low-voltage relief valve 13. It is connected in the hydraulic circuit.

Next, the pump connection solenoid valve 5b is turned on by the first command E1 (for example, energization or transmission of an ON signal) from the controller W, and the pump P is operated without operating the first spool 2b. Oil is supplied to the hydraulic tool U and operated until the cylinder head of the hydraulic tool U is temporarily gripped. As an example, the first state F1 (for example, a temporary gripping state) in which a high-voltage electric wire or the like is sandwiched at a low pressure of about 0.6 [MPa] is set.

Then, when the hydraulic oil supplied to the hydraulic tool U reaches the second pressure value G2 and reaches the first state F1, as an example, the operator operates to release the second command E2 from the controller W. The second solenoid valve 12 is stopped by (for example, power supply stop or OFF signal transmission) to bring the input side of the hydraulic tool U and the low pressure relief valve 13 into a non-connected state in the hydraulic circuit.

Then, when the input side of the hydraulic tool U and the low-pressure relief valve 13 are disconnected in the hydraulic circuit, the hydraulic oil from the pump P is sent to reciprocate the piston 3b of the hydraulic cylinder 4 to increase the pressure. , The increased hydraulic oil is supplied to the hydraulic tool U to operate the cylinder head of the hydraulic tool U. As an example, a high-voltage electric wire or the like is set to a second state F2 (for example, a compressed state or a caulked state) in which a high-voltage electric wire or the like is compressed at a high pressure of 70 [MPa].

After that, when the hydraulic oil supplied to the hydraulic tool U reaches the first pressure value G1, the high-pressure relief valve 9 operates and the pressure switch 8 operates, so that the first command E1 is released (for example, energization stop or energization stop or The pump connection solenoid valve 5b is stopped by the transmission of the OFF signal), and at the same time, the pressure switch 8 is activated or the first command E1 is released to turn on the tank connection solenoid valve 5a. As an example, the tank connecting solenoid valve 5a is operated by a timer signal from the controller W or a timer operation based on a timer attached to the hydraulic booster device 1, and hydraulic oil is discharged from the hydraulic tool U to the tank T. As an example, the timer operating time is set to a time sufficient for the cylinder head of the hydraulic tool U to be fully opened.

As an example, the hydraulic booster device 1 having a temporary grip function has a configuration in which an operator switches ON-OFF of the temporary grip function by a changeover switch or the like. By turning off the temporary gripping function, the input side of the hydraulic tool U and the low-pressure relief valve 13 are disconnected, and the hydraulic oil from the pump P is sent to reciprocate the piston 3b of the hydraulic cylinder 4. As a result, the pressure can be increased, and the cylinder head of the hydraulic tool U can be operated from the open state of the hydraulic tool U to achieve the second state F2 of compression at a high pressure.

Although FIG. 13 has been described by exemplifying the hydraulic booster device 1 having the temporary gripping function, the present embodiment is not limited to the hydraulic booster device 1 having the temporary gripping function, and the temporary gripping function is omitted in the hydraulic tool. In some cases, the cylinder head of the hydraulic tool U is operated from the state in which U is open to obtain the second state F2 in which the hydraulic tool U is compressed at a high pressure. Here, since the hydraulic booster device 1 having a configuration in which the temporary gripping function is omitted has a configuration in which the low-pressure relief portion 11 is omitted, it has a smaller and lighter structure than a configuration having a temporary gripping function.

Subsequently, the operation of the hydraulic cylinder 4 when the cylinder head of the hydraulic tool U is operated to bring the electric wire into the second state F2 in which the electric wire is compressed at a high voltage will be described with reference to the examples of FIGS. 5A and 6A.

(Piston 3b going process)
Hydraulic oil of a predetermined pressure (P pressure) from the pump P is applied to the spool diameter large side of the switching valve portion 2 and the switching check valve 21. The first spool 2b operates to the right due to the diameter difference, and the switching check valve 21 is released by pushing open the switching check valve 21. The hydraulic oil of a predetermined pressure passes through the switching valve portion 2, pressurizes the large diameter side of the piston 3b in the cylinder body 3c of the boosting portion 3 with P pressure, and the piston 3b is pushed to the left (from the state of FIG. 5A to FIG. 6A). Will be in the state of). Then, the hydraulic oil extruded to the piston 3b is discharged, the check valve 22 is temporarily opened, and the increased hydraulic oil is supplied to the cylinder head of the hydraulic tool U.

(Return process of piston 3b)
As shown in FIG. 6A, when the piston 3b in the cylinder body 3c of the pressure boosting portion 3 is pushed to the left to a certain position, the spool diameter large side of the switching valve portion 2 passes through the pressure boosting portion 3 and conducts with the tank T. The pressure on the large spool diameter side in the switching valve portion 2 decreases, the first spool 2b returns to the original position (left side), and the switching check valve 21 also closes. The pressure on the large piston diameter side of the pressure booster 3 decreases, and the piston 3b is pushed back by the predetermined pressure (P pressure) applied to the small piston diameter side of the pressure booster 3 (from the state of FIG. 6A to FIG. 5A). Become a state). When the piston 3b is pushed back to a certain position, hydraulic oil of a predetermined pressure (P pressure) from the pump P is applied to the spool diameter large side of the switching valve portion 2 and the switching check valve 21, and the piston going process is performed again. It starts and repeats this series of operations until the hydraulic oil reaches a predetermined high pressure (first pressure value G1).

(Cylinder head return process in hydraulic tool U)
After repeating the going process of the piston 3b and the returning process of the piston 3b and the pressure of the third port (P2 port) 11a reaches the set pressure, for example, about 70 [MPa], the high pressure relief valve 9 operates and the pressure switch 8 is activated. The hydraulic oil is supplied, the pressure switch 8 detects the pressure, and outputs an arrival signal. When the arrival signal is received by the controller W, the solenoid valve 5 of the directional control unit 7 is switched and the second spool 6b of the directional control valve 6 is switched by a command from the controller W. When a predetermined pressure (P pressure) is applied from the pump P, the pilot check valve 15 operates, the hydraulic oil accumulated in the cylinder head of the hydraulic tool U is discharged to the tank T, and the inside of the cylinder head of the hydraulic tool U is discharged. The cylinder head is fully opened by the restoring force of the spring.

The specifications of the above-mentioned hydraulic booster device 1 may be changed as appropriate according to the specifications and the like. The present invention is not limited to the examples described above, and various modifications can be made without departing from the present invention.

1 Hydraulic booster device 2 Switching valve, 2a body, 2b 1st spool 3 Booster, 3a Cylinder chamber, 3b Piston, 3c Cylinder body 4 Hydraulic cylinder 5 1st solenoid valve, 5a Solenoid valve for tank connection, 5b Pump connection Solenoid valve, 5c body, 5p1 1st flow path, 5p2 3rd flow path, 6-way switching valve, 6a body, 6b 2nd spool, 6e 2nd flow path, 6f 4th flow path, 6g1, 6g2 damper, 6h penetration Hole, 6j Central land, 6k1 1st land, 6k2 2nd land, 6u1 1st notch, 6u2 2nd notch 7 Direction control unit 8 Pressure switch, 8a case, 8b micro switch, 8c holder,
8d poppet, 8d1 flange, 8f spring, 8g fixing member, 8h poppet 9 high pressure relief valve, 9a body, 9b needle valve, 9b1 flange, 9c step, 9d through hole, 9f valve body, 9g adjustment screw, 9h spring 10 manifold part 10a 1st port (P port), 10b 2nd port (T port), 10c body 11 low pressure relief part,
11a 3rd port (P2 port), 11b 4th port (drain port), 11c Body 12 2nd solenoid valve 13 Low pressure relief valve 14 Speed control valve 15 Pilot check valve 16 Check valve 21 Switching check valve 22 Discharge check valve E1 1st command E2 2nd command F1 1st state F2 2nd state G1 1st pressure value (predetermined high voltage)
G2 second pressure value (predetermined low pressure)
K1 Range where the plasma nitriding treatment layer is formed K2, K3 Range where the plasma nitriding treatment layer is not formed P Pump T Tank U Hydraulic tool W Controller

Claims (7)

A hydraulic cylinder having a switching valve portion and a pressure boosting portion, a directional control unit having a first solenoid valve and a directional switching valve, a pressure switch, and a manifold portion having a high pressure relief valve are provided.
The hydraulic oil from the pump is sent, the hydraulic oil increased by the hydraulic cylinder is supplied to the hydraulic tool, and then when the hydraulic oil supplied to the hydraulic tool reaches a predetermined high pressure, the high-pressure relief valve operates. Then, the pressure switch is activated to discharge the hydraulic oil supplied to the hydraulic tool to the tank, and the hydraulic cylinder is increased by operating the first spool built in the body of the switching valve portion. The structure is such that the piston built in the cylinder chamber of the compression unit is operated, and the direction control unit is configured to operate the second spool built in the body of the direction switching valve by the first solenoid valve. A pump connecting solenoid valve for operating the hydraulic oil from the pump so as to be able to send liquid and a tank connecting solenoid valve for operating the hydraulic oil so as to be discharged to the tank are arranged on the body of the first solenoid valve. It ’s a composition,
A hydraulic booster device characterized in that the switching valve portion and the pressure boosting portion have a connected structure or an integrated structure, and the first spool and the piston are arranged side by side. The hydraulic booster device according to claim 1, wherein the cylinder chamber has a plasma nitriding layer formed in a range in contact with the piston. A first port connected to the pump and a second port connected to the tank are provided in the manifold portion.
The hydraulic booster device according to claim 1 or 2, wherein the manifold portion and the hydraulic cylinder have a connected structure or an integral structure. The high-pressure relief valve has a configuration in which a needle valve built in the body operates away from the valve body, and a step that regulates the operating range of the needle valve is formed on the inner wall of the body and operates. The hydraulic booster device according to any one of claims 1 to 3, wherein a plurality of through holes capable of discharging oil are formed in the body. A configuration in which the first solenoid valve is operated by a first command from a controller to send hydraulic oil from the pump, and the piston is operated so that the hydraulic oil supplied to the hydraulic tool reaches the first pressure value. And
Further provided with a low pressure relief portion having a second solenoid valve and a low pressure relief valve,
The second solenoid valve is operated by the second command from the controller to connect the hydraulic tool and the low pressure relief valve, and the hydraulic oil from the pump is supplied to the hydraulic tool without operating the piston. When the hydraulic tool is operated and the hydraulic oil supplied to the hydraulic tool reaches the second pressure value, the low pressure relief valve is operated, and then the hydraulic tool and the low pressure relief valve are disconnected. The hydraulic booster device according to any one of claims 1 to 4, wherein the hydraulic booster device is characterized by the above. The hydraulic booster device according to claim 5, wherein the low-pressure relief portion and the manifold portion have a connected structure or an integral structure. The pressure switch has a configuration in which a micro switch built in a case is operated by a poppet, and the direction control unit and the pressure switch are externally attached to the manifold unit, respectively, according to claims 1 to 6. The hydraulic booster device according to any one item.

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