A needle hydraulic valve

Abstract

The present application relates to the technical field of valve, a needle hydraulic valve, hydraulic cylinder is arranged on the upper part of valve body, valve core is arranged in the valve body, the lower end of valve rod is connected with valve core, the upper end is connected with the piston of oil cylinder, manual operating mechanism includes box cover, operating rod, bevel gear, bevel gear, switching rod and two half circle open and close nuts, the box cover is fixed on the top of hydraulic cylinder, the operating rod passes through the box cover and is rotatably connected with the piston of oil cylinder, the switching rod is rotatably arranged on one side of the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is rotatably arranged in the box cover, the bevel gear is

Description

Technical Field

[0001] This invention relates to the field of valve technology, and more specifically, to a needle-type hydraulic valve. Background Technology

[0002] A needle valve, also known as a hydraulically driven needle valve, is a type of gate valve. It opens and closes by the up-and-down movement of a valve stem. Because it can withstand higher pressures and has better sealing performance than other types of valves, it is commonly used for applications involving smaller flow rates and higher pressures of gas or liquid media. For example, in power plant pressurized water return systems, needle valves are mainly used for tailrace venting, volute venting, volute pressure control, and top cover venting.

[0003] Needle hydraulic valves require manual operation during equipment installation, maintenance, debugging, or switching operation modes at specific locations. Existing technologies, such as the patent document with publication number "CN212718106U," disclose a manual-hydraulic integrated gate valve, which is also a type of shut-off valve. Its working principle is the same: opening and closing the valve is achieved by the up-and-down movement of the valve stem. In this patented solution, the valve stem nut is screwed onto the threaded section of the valve stem. During hydraulic operation, the valve stem nut and valve stem move synchronously. For manual operation, multiple I-beams are inserted into the keyway between the valve stem nut and the valve stem nut seat fixed to the cylinder head, fixing the valve stem nut in place. The valve stem can then be moved up and down by turning it. This method has the following drawbacks:

[0004] (1) Multiple I-shaped keys need to be inserted or removed before each manual and hydraulic switch, which is very inconvenient to operate;

[0005] (2) The method of fixing the valve stem nut by inserting the I-shaped key into the keyway has poor reliability. It is easy to fall off due to vibration and other factors during use. Once it falls off, it will cause the valve to fail in manual mode, that is, the valve has low reliability in manual operation mode. Summary of the Invention

[0006] The purpose of this invention is to provide a needle-type hydraulic valve to overcome the above-mentioned defects of the prior art.

[0007] The embodiments of the present invention are achieved through the following technical solutions:

[0008] A needle-type hydraulic valve includes a valve body, a valve core, a valve stem, a hydraulic cylinder, a cylinder piston, and a manual operating mechanism. The hydraulic cylinder is located above the valve body, the valve core is located inside the valve body, the lower end of the valve stem is connected to the valve core, and the upper end is connected to the cylinder piston. The manual operating mechanism is located above the hydraulic cylinder and includes a cover, an operating rod, a bevel gear, a bevel gear, a switching rod, and two semi-circular opening and closing nuts. The cover is fixed to the top of the hydraulic cylinder, the operating rod passes through the cover and is rotatably connected to the cylinder piston, and the switching rod is rotatably mounted on one side of the cover. The bevel gear is sleeved on the operating rod and rotatably mounted inside the cover, and the bevel gear is located at the inner end of the switching rod and meshes with the bevel gear. The top surface of the bevel gear has an end face thread, and the bottom of the opening and closing nuts has a tooth groove that mates with the end face thread. The two opening and closing nuts are slidably connected to the cover and are located on opposite sides of the operating rod. The operating rod is a threaded rod, and the two opening and closing nuts can mate with the threads on the operating rod when closed.

[0009] Optionally, the manual operating mechanism further includes a pressure equalization valve for balancing the pressure on both sides of the cylinder piston.

[0010] Optionally, the switching rod is connected to a drive assembly for driving the switch handle of the equalizing valve to rotate to achieve switching; the drive assembly includes a gear, a rack, a guide seat and a drive rod, the guide seat is fixedly installed, the gear is fixedly installed on the switching rod, the rack is slidably installed on the guide seat and meshes with the gear, the switch handle of the equalizing valve is provided with a guide groove along the length direction, and the drive rod passes through the guide groove and is fixedly connected to the rack.

[0011] Optionally, a cylinder bracket is provided between the valve body and the hydraulic cylinder, and the cylinder bracket is provided with a locking mechanism for gripping the valve stem.

[0012] Optionally, the locking mechanism includes a variable diameter wheel, a lever, a pull plate, a positioning plate, two clamping blocks, two pull rods, and two return springs. The two pull rods are arranged side by side and pass between the two sides of the cylinder bracket. The two clamping blocks are respectively located on two opposite sides of the valve stem. One clamping block is fixedly connected to the two pull rods and is defined as the first clamping block. The other clamping block is slidably connected to the two pull rods and is positioned as the second clamping block. The return springs are sleeved on the pull rods and abut against the two clamping blocks. The pull plate is located at one end of the pull plate near the second clamping block and is connected between the ends of the two pull rods. The positioning plate is fixedly connected to the cylinder bracket. The variable diameter wheel is rotatably mounted on the positioning plate via a rotating shaft. Both ends of the variable diameter wheel are provided with variable diameter parts and abut against the second clamping block and the pull plate. The lever is connected to the rotating shaft and is used to drive the rotating shaft to rotate. The positioning plate is connected to a positioning component for locking the position of the lever when the two clamping blocks clamp the valve stem.

[0013] Optionally, the cylinder bracket is provided with a valve opening indicator, and the valve stem is provided with an opening pointer.

[0014] Optionally, the valve stem is provided with a detection block, and the cylinder bracket is provided with a lower limit switch and an upper limit switch that can abut against the detection block. The lower limit switch is used to detect the valve closed state, and the upper limit switch is used to detect the valve fully open state.

[0015] Optionally, the bottom of the cylinder piston is provided with a buffer mechanism, which includes a mounting cylinder, a guide cylinder, and a buffer spring. The mounting cylinder is threadedly connected to the cylinder piston. The top of the mounting cylinder is open. The guide cylinder has a large-diameter section and a small-diameter section. The small-diameter section passes through the bottom of the mounting cylinder, and the large-diameter section is slidably connected to the inner wall of the mounting cylinder. The buffer spring is disposed between the bottom of the cylinder piston and the guide cylinder.

[0016] Optionally, a buffer spring is provided between the top of the cylinder piston and the inner top wall of the hydraulic cylinder.

[0017] Optionally, a guide throttling cylinder that cooperates with the valve core is fixed inside the valve body, and the inner wall of the guide throttling cylinder and the side wall of the valve core are both provided with a number of annular grooves spaced apart along the axial direction.

[0018] The present invention has at least the following advantages and beneficial effects: In the present invention, before manual operation, the bevel gear can drive the bevel gear disk to rotate by rotating the switching rod. Since the tooth grooves at the bottom of the two opening and closing nuts are threadedly engaged with the end face of the top surface of the bevel gear disk, and the opening and closing nuts are slidably connected with the cover, the rotation of the bevel gear disk can drive the two semi-circular opening and closing nuts to approach the operating rod, close together to form a whole nut that is threadedly engaged with the operating rod. In this way, the piston of the oil cylinder can be driven up and down by rotating the operating rod, thereby driving the valve rod to move up and down to realize the opening and closing of the valve.

[0019] Compared with the existing method of inserting and unplugging multiple I-shaped keys, rotating the switching rod is more convenient; moreover, the present invention disassembles the whole nut that cooperates with the operating rod into two semi-circular opening and closing nuts, and then uses a specific mechanical structure to drive the opening and closing nuts to close and separate to realize the manual and hydraulic switching method. The structure is more reliable and avoids manual operation failure due to parts falling off. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A front sectional view of a needle-type hydraulic valve provided by the present invention;

[0022] Figure 2A left view of a needle-type hydraulic valve provided by the present invention;

[0023] Figure 3 for Figure 1 Enlarged view of the manual operating mechanism;

[0024] Figure 4 for Figure 3 BB section view in the middle;

[0025] Figure 5 This is a schematic diagram of the guide seat structure;

[0026] Figure 6 A schematic diagram of the connection structure between the rack and the drive rod;

[0027] Figure 7 This is a schematic diagram of the bevel gear disk.

[0028] Figure 8 for Figure 1 AA section view in the middle;

[0029] Figure 9 for Figure 1 Enlarged view of the buffer mechanism;

[0030] Icons: 1-Valve body, 101-Valve body, 102-Valve cover, 2-Valve core, 3-Valve stem, 4-Hydraulic cylinder, 401-Cylinder body, 402-Cylinder cover, 5-Cylinder piston, 6-Manual operating mechanism, 601-Box cover, 602-Operating lever, 603-Bevel gear disc, 604-Bevel gear, 605-Switching lever, 606-Opening nut, 607-First handwheel, 608-Second handwheel, 609-Equalizing valve, 6091-Switch handle, 610-Gear, 611-Rack, 612-Guide seat, 613-Drive lever, 7- 8-Cylinder bracket, 801-Locking mechanism, 802-Variable diameter wheel, 803-Hand lever, 804-Pull plate, 805-First clamping block, 806-Second clamping block, 807-Pull rod, 808-Reset spring, 809-Cylindrical pin, 810-Positioning component, 9-Buffer mechanism, 901-Mounting cylinder, 902-Guide cylinder, 903-Buffer spring, 10-Opening indicator, 11-Opening pointer, 12-Detection block, 13-Upper limit switch, 14-Lower limit switch, 15-Buffer assist spring, 16-Guide throttle cylinder. Detailed Implementation

[0031] refer to Figure 1-2A needle-type hydraulic valve includes a valve body 1, a valve core 2, a valve stem 3, a hydraulic cylinder 4, a cylinder piston 5, and a manual operating mechanism 6. The valve body 1 consists of a valve body 101 and a valve cover 102, with the valve cover 102 connected to the top of the valve body 101 by fasteners (e.g., screws). The hydraulic cylinder 4 consists of a cylinder body 401 and a cylinder cover 402, with the cylinder cover 402 connected to the top of the cylinder body 401 by fasteners (e.g., screws). The cylinder piston 5 is slidably and sealingly disposed within the cylinder body 401. Those skilled in the art should understand that the hydraulic cylinder 4 should be connected to oil pipes for supplying and discharging oil to both sides of the cylinder piston 5. The hydraulic cylinder 4 is located above the valve body 1, the valve core 2 is disposed inside the valve body 1, and the lower end of the valve stem 3 is connected to the valve core 2, while the upper end is connected to the cylinder piston 5. That is, the valve core 2 can be moved up and down by the up and down movement of the cylinder piston 5, thereby realizing the opening and closing of the valve.

[0032] In this embodiment, a guide throttling cylinder 16 that cooperates with the valve core 2 is fixed inside the valve body 1. Specifically, the guide throttling cylinder 16 is pressed tightly by the valve cover 102. With this configuration, the valve core 2 is radially fixed through the guide throttling cylinder 16, preventing the valve core 2 from vibrating under the action of fluid. Furthermore, the inner wall of the guide throttling cylinder 16 and the side wall of the valve core 2 are both provided with several annular grooves at intervals along the axial direction. It is worth noting that the multiple annular grooves along the axial direction make the path of the fluid through the guide throttling of the valve core 2 a multi-step bend, reducing the fluid pressure drop and flow velocity, and the inlet pressure of the next stage is relatively low, ensuring that the pressure of the fluid after throttling is higher than the saturated vapor pressure of the liquid, thus playing a role in preventing cavitation.

[0033] refer to Figure 3-7 The manual operating mechanism 6 is located above the hydraulic cylinder 4. The manual operating mechanism 6 includes a cover 601, an operating lever 602, a bevel gear disc 603, a bevel gear 604, a switching lever 605, and two semi-circular opening and closing nuts 606. The cover 601 is fixed to the top of the hydraulic cylinder 4. The operating lever 602 passes through the cover 601 and is rotatably connected to the cylinder piston 5. That is, the operating lever 602 and the cylinder piston 5 can rotate relative to each other. At the same time, the up and down movement can drive the piston to move up and down. The connection method is not specifically limited. For example, it can be connected by a bearing, or a T-slot is provided at the upper end of the cylinder piston 5, and a T-head is provided at the lower end of the operating lever 602. The T-head is located in the T-slot.

[0034] The switching lever 605 is rotatably mounted on one side of the cover 601. The bevel gear 603 is sleeved on the operating lever 602 and rotatably mounted inside the cover 601. The bevel gear 604 is located at the inner end of the switching lever 605 and meshes with the bevel gear 603. It should be understood that a bearing can be provided at the rotating part to ensure smooth rotation. The top surface of the bevel gear 603 is provided with an end face thread, and the bottom of the opening and closing nut 606 is provided with a tooth groove that mates with the end face thread. The two opening and closing nuts 606 are slidably connected to the cover 601 and are located on two opposite sides of the operating lever 602. Specifically, the cover 601 is provided with a slot, and the opening and closing nuts 606 are located inside the slot and can only move along the side wall of the slot.

[0035] The operating lever 602 is a threaded lever, and the two opening and closing nuts 606, when closed, can engage with the threads on the operating lever 602. Before manual operation, rotating the switching lever 605 will cause the bevel gear 604 to drive the bevel gear disk 603 to rotate. Since the tooth grooves at the bottom of the two opening and closing nuts 606 are threadedly engaged with the end face of the top surface of the bevel gear disk 603, and the opening and closing nuts 606 are slidably connected to the cover 601, the rotation of the bevel gear disk 603 can drive the two semi-circular opening and closing nuts 606 to move closer to the operating lever 602, closing to form a complete nut that engages with the threads on the operating lever 602. In this way, rotating the operating lever 602 can drive the hydraulic cylinder piston 5 to move up and down, thereby driving the valve stem 3 to move up and down to open and close the valve. It is easy to understand that in practical applications, a first handwheel 607 can be set at the outer end of the switching lever 605, and a second handwheel 608 can be set at the top of the operating lever 602 to facilitate the rotation of the switching lever 605 and the operating lever 602.

[0036] Compared with the existing method of inserting and unplugging multiple I-shaped keys, rotating the switching rod 605 is more convenient; moreover, in this invention, the whole nut that cooperates with the operating rod 602 is split into two semi-circular opening and closing nuts 606, and a specific mechanical structure is used to drive the opening and closing nuts 606 to close and separate to realize the manual and hydraulic switching method. The structure is more reliable and avoids manual operation failure due to parts falling off.

[0037] Refer again Figure 3-7Since the hydraulic cylinder piston 5 divides the hydraulic cylinder 4 into two cylinders with different pressures, the cylinder with higher pressure exerts a large thrust on the hydraulic cylinder piston 5 to achieve its up-and-down movement. If the pressures of the two cylinders are not balanced, manual operation is difficult. Therefore, the manual operation mechanism 6 of this invention also includes a pressure equalization valve 609 for balancing the pressures on both sides of the hydraulic cylinder piston 5. In practical applications, the pressure equalization valve 609 is mounted on a support frame, which can be connected and fixed to the cover 601. Furthermore, the switching lever 605 is connected to a drive assembly for driving the switch handle 6091 of the pressure equalizing valve 609 to rotate and achieve switching. The drive assembly includes a gear 610, a rack 611, a guide seat 612, and a drive rod 613. The guide seat 612 is fixedly installed. Specifically, in this embodiment, the guide seat 612 is fixedly connected to the top of the cylinder head 402. The gear 610 is fixedly installed on the switching lever 605, i.e., it rotates synchronously with the switching lever 605. The rack 611 is slidably installed on the guide seat 612 and meshes with the gear 610. The switch handle 6091 of the pressure equalizing valve 609 has a guide groove along its length. The drive rod 613 passes through the guide groove and is fixedly connected to the rack 611. In this embodiment, the rack 611 and the guide seat 612 are connected by a dovetail groove to prevent the rack 611 from slipping off.

[0038] In practical applications, the switch handle 6091 of the equalizing valve 609 is in accordance with... Figure 2 With its tilted arrangement, the rack 611 moves up and down, actuating the pressure equalization valve 609. It should be understood that before manual operation, rotating the switching rod 605 closes the two opening / closing nuts 606, simultaneously driving the drive rod 613 to rotate the switch handle 6091 of the pressure equalization valve 609, causing the valve to open synchronously. Similarly, before hydraulic operation, rotating the switching rod 605 separates the opening / closing nuts 606, and the drive rod 613 simultaneously closes the pressure equalization valve 609. This reduces the number of steps required to switch the pressure equalization valve 609 between manual and hydraulic operation, lowering the risk of misoperation.

[0039] refer to Figure 1 and Figure 8 Based on the above, a cylinder support 7 is provided between the valve body 1 and the hydraulic cylinder 4. The cylinder support 7 is equipped with a locking mechanism 8 for holding the valve stem 3. The locking mechanism 8 can lock the valve stem 3, thereby realizing valve opening lock and avoiding changes in valve opening due to hydraulic failure under hydraulic action.

[0040] In this embodiment, the locking mechanism 8 includes a variable diameter wheel 801, a lever 802, a pull plate 803, a positioning plate 804, two clamping blocks, two pull rods 807, and two return springs 808. The two pull rods 807 are arranged side by side and pass between the two sides of the cylinder bracket 7, meaning that the pull rods 807 can slide. The two clamping blocks are respectively located on two opposite sides of the valve stem 3. One clamping block is fixedly connected to the two pull rods 807, and this clamping block is defined as the first clamping block 805. Specifically, the first clamping block 805 is connected to the pull rods 807 through a cylindrical pin 809. The other clamping block is slidably connected to the two pull rods 807, and this clamping block is positioned as the second clamping block 806.

[0041] A return spring 808 is sleeved on a pull rod 807 and abuts against two clamping blocks. A pull plate 803 is located at one end of the pull plate 803 near the second clamping block 806, and the pull plate 803 is connected between the ends of the two pull rods 807. A positioning plate 804 is fixedly connected to a cylinder bracket 7. A variable diameter wheel 801 is rotatably mounted on the positioning plate 804 via a rotating shaft. Both ends of the variable diameter wheel 801 are provided with variable diameter parts and abut against the second clamping block 806 and the pull plate 803. A lever 802 is connected to a rotating shaft and is used to drive the rotating shaft to rotate.

[0042] After the valve is opened to the appropriate degree, the variable diameter wheel 801 is rotated by turning the hand lever 802. When the variable diameter wheel 801 rotates, one end of the variable diameter wheel 801 can press the second clamping block 806, and the other end of the variable diameter wheel 801 can press the pull plate 803. In this way, when the variable diameter wheel 801 rotates, the second clamping block 806 moves closer to the valve stem 3. At the same time, the variable diameter wheel 801 drives the pull plate 803 away from the valve stem 3, and the pull plate 803 drives the first clamping block 805 to move closer to the valve stem 3. That is, the rotation of the variable diameter wheel 801 causes the first clamping block 805 and the second clamping block 806 to come together and clamp the valve stem 3. In practical applications, measures to increase friction can be taken at the corresponding positions on the two clamping blocks and the valve stem 3 to make the clamping reliable. For example, the contact points between the clamping blocks and the valve stem 3 can be knurled; or the valve stem 3 can be provided with external threads, and the two clamping blocks can be provided with corresponding internal threads. That is, when the two clamping blocks are closed, they are equivalent to a nut that fits with the valve stem.

[0043] Furthermore, a positioning component 810 is connected to the positioning plate 804 to lock the position of the lever 802 when the two clamping blocks grip the valve stem 3. Specifically, in this embodiment, the positioning component 810 is a screw, preferably a wing screw. Both the valve stem 3 and the positioning plate 804 are provided with connecting holes for the screw. In other embodiments, the positioning component 810 can also be a stop bar connected to the positioning plate 804, which restricts the rotation of the lever 802. When it is necessary to activate the valve stem 3 again, the positioning component 810 is removed, and the first clamping block 805 and the second clamping block 806 move away from each other under the action of the return spring 808. The variable diameter wheel 801 and the lever 802 also rotate back to their original positions.

[0044] The cylinder support 7 is equipped with a valve opening indicator 10, and the valve stem 3 is equipped with an opening pointer 11. The opening pointer 11 can move up and down with the valve stem 3 to change the indicating position. The valve opening can be viewed intuitively by the position of the opening pointer 11.

[0045] The valve stem 3 is equipped with a detection block 12, and the cylinder bracket 7 is equipped with a lower limit switch 14 and an upper limit switch 13 that can abut against the detection block 12. The lower limit switch 14 is used to detect the valve closed state, and the upper limit switch 13 is used to detect the valve fully open state. Based on this, it should be understood that the lower limit switch 14 and the upper limit switch 13 are telescopic limit switches. When the valve is closed, the detection block 12 presses the lower limit switch 14 to know that the valve is closed. Similarly, when the valve is fully open (i.e., opened to the maximum opening degree), the detection block 12 presses the upper limit switch 13 to know that the valve has been opened to the maximum opening degree.

[0046] refer to Figure 1 and Figure 9 Based on the above, the present invention has made the following improvements. Specifically, a buffer mechanism 9 is provided at the bottom of the cylinder piston 5. The buffer mechanism 9 includes a mounting cylinder 901, a guide cylinder 902, and a buffer spring 903. The mounting cylinder 901 is threadedly connected to the cylinder piston 5. The top of the mounting cylinder 901 is open. The guide cylinder 902 has a large diameter section and a small diameter section. The small diameter section passes through the bottom of the mounting cylinder 901, and the large diameter section is slidably connected to the inner wall of the mounting cylinder 901. The buffer spring 903 is disposed between the bottom of the cylinder piston 5 and the guide cylinder 902.

[0047] As the valve moves from opening to closing, the piston 5 of the oil cylinder moves downward. Before reaching the closed position, the buffer structure takes effect. The bottom of the guide cylinder 902 first contacts the inner bottom of the hydraulic cylinder 4 and gradually compresses the buffer spring 903. In this way, the impact force of the valve core 2 hitting the valve seat can be reduced, avoiding damage to the sealing surface, and also reducing the noise generated by the impact.

[0048] Furthermore, a buffer spring 15 is provided between the top of the piston 5 and the inner top wall of the hydraulic cylinder 4. This arrangement serves two purposes: firstly, as the valve opening and closing degree gradually increases, i.e., as the piston 5 moves upward, the buffer spring 15 provides a buffering effect, preventing the piston 5 from strongly impacting the cylinder head 402; secondly, since the hydraulic oil is supplied to the hydraulic cylinder 4 by an external speed controller, if a slower closing speed is required or the speed controller malfunctions, the oil pressure will decrease. The force of the piston being pushed by the oil pressure alone may result in insufficient valve seat sealing pressure, causing the valve to not seal tightly. The buffer spring 15 provides additional sealing force to ensure reliable valve sealing.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A needle-type hydraulic valve, comprising a valve body (1), a valve core (2), a valve stem (3), a hydraulic cylinder (4), a cylinder piston (5), and a manual operating mechanism (6), wherein the hydraulic cylinder (4) is disposed above the valve body (1), the valve core (2) is disposed inside the valve body (1), the lower end of the valve stem (3) is connected to the valve core (2), and the upper end is connected to the cylinder piston (5), and the manual operating mechanism (6) is disposed above the hydraulic cylinder (4), characterized in that, The manual operating mechanism (6) includes a cover (601), an operating lever (602), a bevel gear disc (603), a bevel gear (604), a switching lever (605), and two semi-circular opening and closing nuts (606). The cover (601) is fixed to the top of the hydraulic cylinder (4). The operating lever (602) passes through the cover (601) and is rotatably connected to the piston (5) of the cylinder. The switching lever (605) is rotatably mounted on one side of the cover (601). The bevel gear disc (603) is sleeved on the operating lever (602) and rotatably mounted on it. The bevel gear (604) is located inside the cover (601) and is located at the inner end of the switching rod (605) and meshes with the bevel gear disc (603). The top surface of the bevel gear disc (603) is provided with an end face thread, and the bottom of the opening and closing nut (606) is provided with a tooth groove that mates with the end face thread. The two opening and closing nuts (606) are slidably connected to the cover (601) and are located on two opposite sides of the operating rod (602). The operating rod (602) is a threaded rod, and the two opening and closing nuts (606) can mate with the thread on the operating rod (602) after they are closed. The manual operating mechanism (6) also includes a pressure equalization valve (609) for balancing the pressure on both sides of the cylinder piston (5); The switching lever (605) is connected to a drive assembly for driving the switch handle (6091) of the equalizing valve (609) to rotate and achieve switching. The drive assembly includes a gear (610), a rack (611), a guide seat (612), and a drive rod (613). The guide seat (612) is fixedly installed, the gear (610) is fixedly installed on the switching lever (605), and the rack (611) is slidably installed on the guide seat (612) and meshes with the gear (610). The switch handle (6091) of the equalizing valve (609) is provided with a guide groove along the length direction, and the drive rod (613) passes through the guide groove and is fixedly connected to the rack (611).

2. The needle-type hydraulic valve according to claim 1, characterized in that, A cylinder support (7) is provided between the valve body (1) and the hydraulic cylinder (4), and the cylinder support (7) is provided with a locking mechanism (8) for clamping the valve stem (3).

3. The needle-type hydraulic valve according to claim 2, characterized in that, The locking mechanism (8) includes a variable diameter wheel (801), a lever (802), a pull plate (803), a positioning plate (804), two clamping blocks, two pull rods (807), and two return springs (808). The two pull rods (807) are arranged side by side and pass between the two sides of the cylinder bracket (7). The two clamping blocks are respectively located on two opposite sides of the valve stem (3). One clamping block is fixedly connected to the two pull rods (807), and this clamping block is defined as the first clamping block (805). The other clamping block is slidably connected to the two pull rods (807), and this clamping block is positioned as the second clamping block (806). The return springs (808) are... 8) Sleeve onto the pull rod (807) and abut against the two clamping blocks; pull plate (803) is connected between the ends of the two pull rods (807); positioning plate (804) is fixedly connected to the cylinder bracket (7); variable diameter wheel (801) is rotatably mounted on positioning plate (804) via a rotating shaft; both ends of variable diameter wheel (801) are provided with variable diameter parts and abut against the second clamping block (806) and pull plate (803); hand lever (802) is connected to the rotating shaft and is used to drive the rotating shaft to rotate; positioning plate (804) is connected with positioning component (810) for locking the position of hand lever (802) when the two clamping blocks clamp the valve stem (3).

4. The needle-type hydraulic valve according to claim 3, characterized in that, The cylinder support (7) is provided with a valve opening indicator (10), and the valve stem (3) is provided with an opening pointer (11).

5. The needle-type hydraulic valve according to claim 3, characterized in that, The valve stem (3) is provided with a detection block (12), and the cylinder bracket (7) is provided with a lower limit switch (14) and an upper limit switch (13) that can abut against the detection block (12). The lower limit switch (14) is used to detect the valve closed state, and the upper limit switch (13) is used to detect the valve fully open state.

6. The needle hydraulic valve according to claim 1, characterized in that, The bottom of the cylinder piston (5) is provided with a buffer mechanism (9). The buffer mechanism (9) includes a mounting cylinder (901), a guide cylinder (902), and a buffer spring (903). The mounting cylinder (901) is screwed to the cylinder piston (5). The top of the mounting cylinder (901) is open. The guide cylinder (902) has a large diameter section and a small diameter section. The small diameter section passes through the bottom of the mounting cylinder (901), and the large diameter section is slidably connected to the inner wall of the mounting cylinder (901). The buffer spring (903) is located between the bottom of the cylinder piston (5) and the guide cylinder (902).

7. The needle-type hydraulic valve according to claim 1, characterized in that, A buffer spring (15) is provided between the top of the piston (5) and the inner top wall of the hydraulic cylinder (4).

8. The needle hydraulic valve according to claim 1, characterized in that, The valve body (1) is fixedly provided with a guide throttle cylinder (16) that cooperates with the valve core (2). The inner wall of the guide throttle cylinder (16) and the side wall of the valve core (2) are both provided with a number of annular grooves at intervals along the axial direction.

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