Buffer valve for hydraulic motor and hoist control hydraulic system

Abstract

The present disclosure provides a buffer valve of a hydraulic motor and a hoist control hydraulic system, and belongs to the technical field of hydraulic hoist control. The buffer valve comprises a valve body, a valve core and an elastic member. The valve body has a first oil port, a second oil port and a control oil port. The valve core is movably located in the valve body and at the communication between the first oil port of the valve body and the second oil port of the valve body. An end face of the valve core and the valve body form a first cavity. The elastic member is located in the annular gap and is sleeved outside the valve core. One end of the elastic member abuts against the inner wall of the valve body, and the other end of the elastic member abuts against the outer wall of the valve core. The valve core is configured to move under the action of the first cavity and the elastic member to change the size of the communication opening between the first oil port and the second oil port. The present disclosure can control the rope releasing speed of the hoist winch driven by the hydraulic motor.

Description

Technical Field

[0001] This disclosure belongs to the field of hydraulic lifting control technology, and specifically relates to a buffer valve for a hydraulic motor and a lifting control hydraulic system. Background Technology

[0002] Crane hoisting winches are often driven by multi-cavity vane hydraulic motors, such as three-cavity vane hydraulic motors.

[0003] In related technologies, when the hydraulic motor needs to rotate forward to drive the hoisting winch to take up the rope and lift the load, the three working oil chambers of the hydraulic motor can simultaneously receive and discharge oil. When the hydraulic motor needs to rotate in reverse to drive the hoisting winch to release the rope and lower the load, only one working oil chamber of the hydraulic motor (which can be called the main working chamber) receives oil, while all three working oil chambers discharge oil simultaneously. With the same oil flow rate from the hydraulic motor, the rope release speed of the hoisting winch can reach three times the rope take-up speed.

[0004] However, in practice, due to the maximum speed limitations of components such as bearings and blades, the rope-laying speed of hydraulic motors is generally required to be limited to less than three times the rope-reeling speed (generally not exceeding 2.5 times the rope-reeling speed) to prevent damage caused by exceeding the service limits of the components. The rope-laying speed of the hoisting winch controlled by the aforementioned hydraulic motor is often greater than 2.5 times the rope-reeling speed, thus failing to meet the usage requirements. Summary of the Invention

[0005] This disclosure provides a buffer valve for a hydraulic motor, which can be used in conjunction with a multi-chamber vane hydraulic motor to control the rope-laying speed of a hoisting winch driven by the hydraulic motor. The technical solution is as follows: This disclosure provides a buffer valve for a hydraulic motor, which is connected to a hydraulic motor in a lifting control hydraulic system. The hydraulic motor includes a first working oil chamber, a second working oil chamber, and a third working oil chamber. The buffer valve includes a valve body, a valve core, and an elastic element. The valve body has a first oil port, a second oil port, and a control oil port. The first oil port of the valve body is connected to the second oil port of the first working oil chamber, and the second oil port of the valve body is connected to the second oil ports of the second and third working oil chambers, respectively. The control oil port is selectively connected to an oil tank. The valve core is movably located within and within the valve body. At the connection between the first oil port and the second oil port of the valve body, a first cavity is formed between one end face of the valve core and the valve body. The first cavity is connected to the control oil port. An annular gap is defined between the outer peripheral wall of the end of the valve core away from the first cavity and the valve body. The annular gap communicates with the first cavity through the interior of the valve core. The elastic element is located within the annular gap and is sleeved on the outside of the valve core. One end of the elastic element abuts against the inner wall of the valve body, and the other end of the elastic element abuts against the outer wall of the valve core. The valve core is configured to move under the action of the first cavity and the elastic element to change the size of the communication opening between the first oil port and the second oil port.

[0006] In another implementation of this disclosure, the valve core includes an outer ring sleeve and an inner valve core. The inner valve core is located inside the end of the outer ring sleeve facing the first cavity. The outer circle of the inner valve core is clearance-fitted with and connected to the inner circumferential wall of the outer ring sleeve. The inner valve core has an axial channel and a damping hole. The axial channel extends in the same direction as the axis of the outer ring sleeve. The damping hole penetrates the side wall of the inner valve core and communicates with the middle of the axial channel. The axial channel communicates with the first cavity. The side wall of the outer ring sleeve has a connecting hole. The connecting hole is located on the side of the damping hole away from the first cavity and communicates with the annular gap. The connecting hole communicates with the damping hole through the gap between the inner valve core and the outer ring sleeve.

[0007] In another implementation of this disclosure, the axial channel includes a first hole segment and a second hole segment connected to each other along its own axial direction. The second hole segment is located between the first hole segment and the first cavity. The inner diameter of the first hole segment is not less than the inner diameter of the second hole segment. The valve core also includes a ball head located in the first hole segment, and the ball head has a radius greater than the inner diameter of the second hole segment.

[0008] In another implementation of this disclosure, the first oil port and the second oil port are respectively located in two adjacent side walls of the valve body; the outer ring sleeve includes a cone head and a collar, the larger outer diameter end of the cone head is connected to the first end of the collar, the smaller outer diameter end of the cone head faces the second oil port and is coaxially arranged with the second oil port; the second end of the collar faces the first cavity, and the outer wall of the collar near the second end has an annular step; the elastic element is sleeved on the cone head, and one end abuts against the step surface of the step facing the cone head.

[0009] In another implementation of this disclosure, the outer ring sleeve further includes an adjusting ring, which is sleeved outside the outer ring sleeve. The two ends of the adjusting ring along the axial direction are respectively clamped between the step surface of the step facing the cone and the end of the elastic member facing the first cavity.

[0010] In another implementation of this disclosure, the valve body includes a valve block and a valve stem. One end of the valve stem is located inside the valve block and, together with the inner wall of the valve block, defines a first cavity with the valve core. The other end of the valve stem is located outside the valve block. The valve stem is connected to the valve block and is movable relative to the valve block along its own axis.

[0011] On the other hand, a lifting control hydraulic system is also provided, comprising a proportional directional valve, a hydraulic motor, and the aforementioned buffer valve. The inlet of the proportional directional valve is connected to an oil pump, and the outlet of the proportional directional valve is connected to an oil tank. The first working port of the proportional directional valve is connected to the first ports of the first, second, and third working chambers of the hydraulic motor. The second working port of the proportional directional valve is connected to the second port of the first working chamber. When the first working port of the proportional directional valve is connected to its own inlet and the second working port of the proportional directional valve is connected to its own outlet, the hydraulic... When the motor rotates forward, the first working port of the proportional directional valve is connected to its own outlet and the second working port of the reversing valve is connected to its own inlet; the hydraulic motor rotates in reverse; the second port of the second working oil chamber is connected to the second port of the third working oil chamber; the buffer valve is connected between the second working port of the proportional directional valve and the second port of the second working oil chamber, the first port of the buffer valve is connected to the second port of the first working oil chamber and the second working port of the proportional directional valve respectively, and the second port of the buffer valve is connected to the second port of the second working oil chamber, the second port of the third working oil chamber and the first working port of the proportional directional valve respectively.

[0012] In another implementation of this disclosure, the lifting control hydraulic system further includes a hydraulic directional valve and a pilot relief valve. Both the hydraulic directional valve and the pilot relief valve are connected in the oil line between the outlet of the proportional directional valve and the control port of the buffer valve. The first port of the hydraulic directional valve is connected to the control port of the buffer valve, and the second port of the hydraulic directional valve is connected to the inlet of the pilot relief valve. The control port of the hydraulic directional valve is connected to the first port of the first working oil chamber, the second port of the second working oil chamber, and the third port of the third working oil chamber, respectively. The outlet of the pilot relief valve is connected to the outlet of the proportional directional valve and the oil tank, respectively, and the control port of the pilot relief valve is connected to its own inlet. The spring setting pressure of the pilot relief valve is greater than the spring setting pressure of the hydraulic directional valve.

[0013] In another implementation of this disclosure, the lifting control hydraulic system further includes a first switching valve and a second switching valve. The first switching valve is connected between a first oil port of the first working oil chamber and a first oil port of the second working oil chamber. The first switching valve is configured to: connect the first oil port of the second working oil chamber to the first oil port of the first working oil chamber when the hydraulic motor reverses; and connect the first oil port of the second working oil chamber to the first oil port of the first working oil chamber when the hydraulic motor rotates forward and the oil pressure at the first oil port of the first working oil chamber is higher than a first threshold. The second switching valve is connected between the first oil port of the second working oil chamber and the first oil port of the third working oil chamber of the motor. The second switching valve is configured to: connect the first oil port of the third working oil chamber to the first oil port of the first working oil chamber through the second switching valve when the hydraulic motor reverses; and connect the first oil port of the third working oil chamber of the motor to the first oil port of the second working oil chamber when the hydraulic motor rotates forward and the oil pressure at the first oil port of the first working oil chamber is higher than a second threshold.

[0014] In another implementation of this disclosure, the lifting control hydraulic system further includes a first check valve, which is connected between the second port of the third working oil chamber and the first port of the third working oil chamber. The inlet of the first check valve is connected to the second port of the third working oil chamber and the second port of the second working oil chamber, and the outlet of the first check valve is connected to the first port of the third working oil chamber.

[0015] The beneficial effects of the technical solutions provided in this disclosure are: Because the buffer valve also includes a valve core and an elastic element, and the valve core is movably located within the valve body, the valve core is configured to move under the action of the first chamber and the elastic element, changing the connection between the first and second oil ports. Therefore, when the buffer valve is connected to the lifting control hydraulic system, if the hydraulic motor rotates forward to lift the load (retract the rope), oil enters all three working chambers of the hydraulic motor, while low-pressure oil is discharged from the second oil ports of the first, second, and third working chambers of the hydraulic motor. Since the second oil port of the buffer valve is connected to the second oil ports of the second and third working chambers of the hydraulic motor, respectively, some of the oil discharged from the hydraulic motor enters the second oil port of the buffer valve, flows out through the first oil port, and then merges with the oil discharged from the first working chamber of the hydraulic motor before being discharged.

[0016] If the hydraulic motor reverses to lower the load (unwind the rope), only one working chamber of the hydraulic motor receives oil, while all three working chambers simultaneously discharge oil. Therefore, some of the pressurized oil entering the second port of the first working chamber of the hydraulic motor will enter the first working chamber to drive the hydraulic motor to reverse, while the rest will enter the first port of the buffer valve and be discharged through the second port. This allows the buffer valve to divert some of the pressurized oil entering the first working chamber of the hydraulic motor, thereby reducing the motor's speed and controlling the hoisting winch speed, preventing the rope unwinding speed from becoming excessive.

[0017] Furthermore, when the hydraulic motor reverses, the valve core makes the connection between the first and second oil ports variable. Therefore, the flow rate of the pressure oil diverted from the first working oil chamber of the hydraulic motor by the buffer valve will change. This can further change the speed of the hydraulic motor and achieve the purpose of controlling the speed of the hoisting winch, so that the rope release speed is not too high. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the structure of the buffer valve provided in the embodiments of this disclosure; Figure 2 for Figure 1 A partial structural diagram of the valve core in the diagram; Figure 3 for Figure 2 A bottom view of the inner valve core; Figure 4This is a schematic diagram of the valve sleeve structure; Figure 5 for Figure 1 Top view; Figure 6 This is a schematic diagram of a lifting control hydraulic system provided in an embodiment of the present disclosure.

[0020] The symbols in the diagram represent the following meanings: 1. Valve body; 101. First oil port; 102. Second oil port; 103. Control oil port; 11. Valve block; 111. End cap; 112. Valve block body; 113. Valve sleeve; 1131. Limiting groove; 1120. Receiving hole; 1130. Opening; 12. Valve stem; 3. Valve core; 301. First chamber; 3001. Annular gap; 31. Outer ring; 310. Slot; 311. Cone; 312. Collar; 3120. Step; 313. Adjusting ring; 32. Inner valve core; 320. Axial channel; 3200. Damping hole; 3201. First hole section; 3202. Second hole section; 3203. Radial channel; 33. Retaining ring; 34. Ball head; 302. Throttling channel; 303. Connecting hole; 304. Annular flow channel; 3220. Diverting hole; 4. Elastic components; 100. Proportional directional valve; 200. Hydraulic motor; 201. First working oil chamber; 202. Second working oil chamber; 203. Third working oil chamber; 300, buffer valve; 400, hydraulic directional valve; 500, pilot-operated relief valve; 600, First switching valve; 601, One-way sub-valve; 602, Reversing sub-valve; 700, Second switching valve; 800, Balancing valve; 900, Safety valve; 1100, First check valve; 1200, Second check valve; 1300, Third check valve. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0022] In related technologies, a three-chamber vane hydraulic motor has three working oil chambers (including one main working chamber and two auxiliary working chambers).

[0023] When a hydraulic motor drives a hoisting winch to wind up a load, all three working oil chambers of the motor can simultaneously receive and discharge oil. In this case, all three working oil chambers are engaged, and the hydraulic motor operates at its maximum displacement (Dmax). Pressurized oil enters the first port of the three working oil chambers, driving the motor to rotate forward and generating high torque to overcome the load's gravity. The oil is then discharged from the second port of the three working oil chambers.

[0024] Under the oil inlet flow rate Q, the rope winding speed of the hoisting winch satisfies the following formula (1): N in =Q / Dmax; (1) Where, N in The rope winding speed is represented by Dmax, which is the total displacement of the motor, corresponding to the total working volume of the three chambers. For example, if the displacement of each chamber is d, then Dmax = 3d.

[0025] When the hydraulic motor drives the hoisting winch to lower the load by releasing the rope, only the main working chamber of the hydraulic motor receives oil, but all three working chambers simultaneously discharge oil to support the load. The load descends under gravity, driving the hydraulic motor to rotate. Pressurized oil is only supplied to the main working chamber of the hydraulic motor, with the inlet flow rate remaining Q (the same as during rope retraction). The first port of each of the three working chambers is connected to a back pressure valve or control valve, which provides back pressure to support the load, prevent free fall, and control the descent speed.

[0026] In other words, when the load decreases, the weight of the load pulls the wire rope, causing the hoisting winch to rotate passively. At the same time, the hydraulic motor is driven to rotate in the opposite direction, reducing the volume of the two auxiliary working oil chambers of the hydraulic motor and forcibly discharging the oil. Furthermore, when the hydraulic motor rotates in the opposite direction, the volume of the main working oil chamber expands, creating a partial vacuum. If oil is not replenished in time, cavitation will occur. Replenishing oil in the main working oil chamber in time can prevent cavitation.

[0027] Because only one main working chamber receives oil, the effective displacement of the hydraulic motor is reduced. During rope unloading, for each revolution of the hydraulic motor, only the chamber receiving oil needs to be filled (displacement is...). d Meanwhile, other chambers discharge oil under load but are unaffected by the supply of pressurized oil. Therefore, the effective displacement of the hydraulic motor is reduced to the displacement d of a single chamber, which is one-third of the displacement during rope winding.

[0028] Under the same oil inlet flow rate Q, the rope release speed satisfies the following formula (2): N Out =Q / d=3Q / D max (2) Where, N Out The value is the rope release speed. The meanings of other parameters are the same as in formula (1).

[0029] Therefore, with the same oil flow rate, the rope release speed of a hydraulic motor can reach three times the rope take-up speed.

[0030] Figure 1 This is a schematic diagram of the structure of the buffer valve provided in the embodiments of this disclosure, combined with... Figure 1 The buffer valve is used in conjunction with a hydraulic motor in a lifting control hydraulic system. The hydraulic motor includes three working oil chambers: a first working oil chamber 201, a second working oil chamber 202, and a third working oil chamber 203. Each of the three working oil chambers has a first oil port and a second oil port.

[0031] The buffer valve 300 includes a valve body 1, a valve core 3, and an elastic element 4. The valve body 1 has a first oil port 101, a second oil port 102, and a control oil port 103. The first oil port 101 of the valve body 1 is used to connect to the second oil port of the first working oil chamber 201. The second oil port 102 of the valve body 1 is used to connect to the second oil port of the second working oil chamber 202 and the second oil port of the third working oil chamber 203, respectively. The control oil port 103 is used to selectively connect to the oil tank.

[0032] The valve core 3 is movably located in the valve body 1 and is located at the connection between the first oil port 101 and the second oil port 102 of the valve body 1. A first cavity 301 is formed between one end face of the valve core 3 and the valve body 1. The first cavity 301 is connected to the control oil port 103. An annular gap 3001 is defined between the outer peripheral wall of the end of the valve core 3 away from the first cavity 301 and the valve body 1.

[0033] The valve core 3 has a throttling channel 302, one end of which communicates with the first cavity 301, and the other end of which communicates with the annular gap 3001. An elastic element 4 is located within the annular gap 3001 and is fitted over the valve core 3. One end of the elastic element 4 abuts against the inner wall of the valve body 1, and the other end abuts against the outer wall of the valve core 3. The valve core 3 is configured to move under the action of the first cavity 301 and the elastic element 4 to change the size of the communication opening between the first oil port 101 and the second oil port 102.

[0034] When the buffer valve provided in this embodiment is used in conjunction with a hydraulic motor to drive a hoisting winch to lift or lower a load, the buffer valve is connected to the first working oil chamber 201 of the hydraulic motor through the first oil port 101, and at the same time connected to the second working oil chamber 202 and the third working oil chamber 203 of the hydraulic motor through the second oil port 102. It is also connected to the oil tank through the control oil port 103, thereby connecting the buffer valve to the hoisting control hydraulic system.

[0035] Since the valve core 3 is movably located within the valve body 1, and is configured to move under the action of the first chamber 301 and the elastic element 4, the connection between the first oil port 101 and the second oil port 102 can be changed. Therefore, when the buffer valve is connected to the lifting control hydraulic system, during the forward rotation of the hydraulic motor to lift the load (rope winding), oil enters all three working oil chambers of the hydraulic motor, while low-pressure oil is discharged from the second oil port of the first working oil chamber 201, the second oil port of the second working oil chamber 202, and the second oil port of the third working oil chamber 203. Since the second oil port 102 of the buffer valve is connected to the second oil port of the second working oil chamber 202 and the second oil port of the third working oil chamber 203 of the hydraulic motor, the oil discharged from the second working oil chamber 202 and the third working oil chamber 203 of the hydraulic motor will enter the second oil port 102 of the buffer valve. Since the second oil port 102 of the buffer valve is connected to the first oil port 101, the oil entering the second oil port 102 will flow along the first oil port 101 and converge with the oil discharged from the second oil port of the first working oil chamber 201 of the hydraulic motor before being discharged.

[0036] During the process of the hydraulic motor reversing to lower the load (unwinding the rope), oil enters only the first working chamber of the hydraulic motor, while oil exits from all three working chambers simultaneously. Therefore, a portion of the pressurized oil passing through the second port of the first working chamber 201 of the hydraulic motor enters the first working chamber 201 to drive the hydraulic motor to reverse, while the other portion enters the first port 101 of the buffer valve 300 and is discharged through the second port 102. In this way, the buffer valve 300 diverts a portion of the pressurized oil entering the first working chamber 201 of the hydraulic motor, thereby reducing the speed of the hydraulic motor 200 and controlling the speed of the hoisting winch, ensuring that the rope unwinding speed is not excessive.

[0037] Furthermore, since the control port 103 is selectively connected to the oil tank, when the hydraulic motor 200 reverses, some of the oil entering the first port 101 of the buffer valve 300 will enter the first chamber 301 through the annular gap 3001 and the throttling channel 302. The oil pressure in the first chamber 301 (greater than the oil pressure at the second port 102, which is connected to the oil tank at this time) drives the valve core 3 to move, reducing the connection area between the first port 101 and the second port 102 of the buffer valve. This reduces the flow rate of the pressure oil diverted from the first working oil chamber 201 of the hydraulic motor, thereby further reducing the speed of the hydraulic motor and further controlling the speed of the hoisting winch, so that the rope release speed is not too high. When it is necessary to further increase the speed of the hydraulic motor, the control port 103 can be connected to the oil tank, so that the pressure of the first chamber 301 decreases, the valve core 3 moves in the opposite direction, and the communication area between the first port 101 and the second port 102 in the buffer valve increases, thereby increasing the flow rate of the pressure oil diverted from the first working oil chamber 201 of the hydraulic motor by the buffer valve.

[0038] In this embodiment, the area of ​​the oil in the first chamber 301 acting on the valve core 3 is larger than the area of ​​the oil in the second port 102 acting on the valve core 3. Thus, when the control port 103 is closed, the pressure in the first chamber 301 is greater than the pressure in the second port 102, causing the valve core 3 to move downward.

[0039] To clarify, in the embodiments of this disclosure Figure 1 The state shown is when the valve core 3 moves to its limit position under the action of the elastic element 4. At this time, the communication area between the first oil port 101 and the second oil port 102 in the buffer valve is the largest.

[0040] Optionally, the first oil port 101 and the second oil port 102 are located in two adjacent side walls of the valve body 1, respectively. The control oil port 103 is located on the side wall away from the second oil port 102, and the side wall in which it is located is arranged opposite to the side wall in which the first oil port 101 is located.

[0041] Figure 2 for Figure 1 A partial structural diagram of the valve core is shown in the diagram. Figure 2 The valve core 3 includes an outer ring sleeve 31 and an inner valve core 32. The inner valve core 32 is located inside the end of the outer ring sleeve 31 facing the first cavity 301. The outer circle of the inner valve core 32 is in clearance fit with and connected to the inner circumferential wall of the outer ring sleeve 31.

[0042] The inner valve core 32 has an axial channel 320 and a damping hole 3200. The axial channel 320 extends in the same direction as the axis of the outer ring sleeve 31. The damping hole 3200 penetrates the side wall of the inner valve core 32 and communicates with the middle part of the axial channel 320. The axial channel 320 is connected to the first cavity 301.

[0043] The outer ring sleeve 31 has a connecting hole 303 in its sidewall. The connecting hole 303 is located on the side of the damping hole 3200 away from the first cavity 301 and communicates with the annular gap 3001. The connecting hole 303 communicates with the damping hole 3200 through the gap between the inner valve core 32 and the outer ring sleeve 31. The axial channel 320, the damping hole 3200 and the connecting hole 303 form a throttling channel 302.

[0044] In the above implementation, the outer ring sleeve 31 provides a mounting base for the inner valve core 32. The inner valve core 32 provides a mounting base for the axial channel 320. Simultaneously, the axial channel 320 connects the annular gap 3001 and the first cavity 301.

[0045] The damping orifice 3200 is used to achieve throttling and pressure limiting after the first chamber 301 is connected to the oil tank through the pilot relief valve 500 and the hydraulic directional valve 400 (which will be led out in the lifting control hydraulic system later). This makes the pressure in the first chamber 301 less than the pressure in the annular gap 3001. Thus, when the hydraulic motor reverses, the pressure in the first chamber 301 will be less than the pressure in the annular gap 3001, allowing the valve core 3 to move toward the first chamber 301. This increases the communication area between the first oil port 101 and the second oil port 102, making the opening of the buffer valve larger, increasing the diverted oil, and reducing the amount of oil entering the hydraulic motor, thereby limiting the speed of the hydraulic motor.

[0046] The above statement that the outer circle of the inner valve core 32 is fitted and connected to the inner circumferential wall of the outer ring sleeve 31 with clearance means that the inner valve core 32 is assembled in the outer ring sleeve 31 and can move synchronously with the outer ring sleeve 31. At the same time, there is a gap between the inner valve core 32 and the outer ring sleeve 31 in the circumferential direction for oil flow.

[0047] To accelerate the flow of oil into the axial channel 320, multiple connecting holes 303 are provided, spaced apart circumferentially along the outer ring sleeve 31. Simultaneously, the outer ring sleeve 31 has annular flow channels 304 communicating with each connecting hole 303, the inner diameter of which is larger than the inner diameter of the outer ring sleeve 31.

[0048] In this embodiment, the inner valve core 32 also has a diversion hole 3220 in the side wall near the first cavity 301. One end of the diversion hole 3220 is connected to the axial channel 320, and the other end is connected to the first cavity 301. The diversion hole 3220 allows the oil in the axial channel 320 to flow quickly into the first cavity 301.

[0049] Optionally, the valve core 3 further includes a retaining ring 33, which is located in the outer ring sleeve 31 and on the side of the inner valve core 32 facing the first cavity 301. The two ends of the retaining ring 33 along the axial direction of the outer ring sleeve 31 are respectively engaged in the outer ring sleeve, and one end of the retaining ring 33 is in contact with the inner valve core 32.

[0050] In the above implementation, the outer ring sleeve 31 is used to move in the valve body 1 in order to control the size of the communication opening between the first oil port 101 and the second oil port 102, and at the same time provide a mounting base for the inner valve core 32.

[0051] The retaining ring 33 is used to axially limit the inner valve core 32, so that the inner valve core 32 can be limited within the outer ring sleeve 31 and move synchronously with the outer ring sleeve 31.

[0052] To facilitate the installation of the retaining ring 33, the outer ring sleeve 31 has an annular groove 310 inside, in which the retaining ring 33 is located. Furthermore, the retaining ring 33 consists of two semi-rings. This facilitates installation within the groove 310.

[0053] In other examples, the retaining ring 33 may also be other limiting structures, such as a protrusion.

[0054] Optionally, the axial channel 320 includes a first orifice 3201 and a second orifice 3202 connected to each other along its own axial direction. The second orifice 3202 is located between the first orifice 3201 and the first cavity 301, and the inner diameter of the first orifice 3201 is not less than the inner diameter of the second orifice 3202. The valve core 3 also includes a ball head 34, which is located in the first orifice 3201 and has a radius greater than the inner diameter of the second orifice 3202.

[0055] In the above implementation, due to the clearance fit between the end face of the inner valve core 32 away from the first cavity 301 and the inner wall of the outer ring sleeve 31, the oil in the annular gap 3001 can enter the axial channel 320 not only through the damping hole 3200, but also through the gap between the end face of the inner valve core 32 away from the first cavity 301 and the inner wall of the outer ring sleeve 31, thus allowing the oil to quickly enter the first cavity 301. The ball head 34 is used to reduce the impact when the valve core 3 moves upward to contact the valve body 1, playing a throttling and buffering role. Because when the rope is released, after the valve core 3 moves down to the limit position under the pressure of the first cavity 301, in case of an emergency, when the proportional directional valve 100 (described below) in the lifting control hydraulic system needs to return to the neutral position, the oil inlet and two working oil ports of the proportional directional valve 100 are connected to the oil outlet of the proportional directional valve 100. At this time, the oil pressure at the first oil port 101 and the second oil port 102 of the buffer valve will drop. The valve core 3 will move upward under the action of the elastic element 4. The arrangement of the ball head 34 will cause the oil in the first chamber 301 to flow along the axial channel 320 and the gap between the ball head 34 and the first hole section 3201. The presence of the ball head 34 can limit the flow rate of the oil when it flows out through the axial channel 320, thereby indirectly causing the first chamber 301 to be pressurized, limiting the upward movement speed of the valve core 3, playing a buffering and flow limiting role, and preventing abnormal noise caused by impact with the valve body 1.

[0056] For example, the ball head 34 is a steel ball.

[0057] In this embodiment, the inner diameter of the first hole segment 3201 decreases progressively along the direction from the first hole segment 3201 to the second hole segment 3202. Exemplarily, the inner wall of the first hole segment 3201 is covered with a conical surface. The first hole segment 3201 has a funnel shape.

[0058] Figure 3 for Figure 2 A bottom view of the inner valve core, combined with Figure 3 To further achieve the throttling and buffering effect, the inner valve core 32 has a radial channel 3203 in the end face away from the first cavity 301. The radial channel 3203 is located on the diameter of the end face where the inner valve core 32 is located, and its two ends are located on the opposite side walls of the inner valve core 32. The radial channel 3203 communicates with the first hole section 3201.

[0059] With the above configuration, when the valve core 3 moves upward as a whole, some of the oil in the first chamber 301 will pass through the conical surface between the ball head 34 and the first hole section 3201, and then flow out from the radial channel 3203. Therefore, a portion of the oil can be diverted through the radial channel 3203, thereby indirectly causing the first chamber 301 to be pressurized, slowing down the movement speed of the valve core 3, preventing it from colliding with the valve body 1, and playing a throttling and buffering role.

[0060] Optionally, the outer ring 31 includes a cone head 311 and a collar 312. The end of the cone head 311 with a larger outer diameter is connected to the first end of the collar 312, and the end of the cone head 311 with a smaller outer diameter faces the second oil port 102 and is coaxially arranged with the second oil port 102. The second end of the collar 312 faces the first cavity 301, and the outer wall of the collar 312 near the second end has an annular step 3120. The elastic member 4 is sleeved on the outside of the cone head 311, and one end abuts against the stepped surface of the step 3120 facing the cone head 311.

[0061] In the above implementation, with the outer ring 31 configured as described above, the size of the communication opening between the first oil port 101 and the second oil port 102 can be adjusted by adjusting the depth of the cone 311 inserted into the second oil port 102. The collar 312 is used to connect with the inner valve core 32 and abuts against one end of the elastic member 4.

[0062] See you again Figure 1 Optionally, the outer ring sleeve 31 also includes an adjusting ring 313, which is sleeved on the outer ring sleeve 31. The two ends of the adjusting ring 313 along the axial direction are respectively clamped between the step surface of the step 3120 facing the cone head 311 and the end of the elastic member 4 facing the first cavity 301.

[0063] In the above implementation, the setting of the adjusting ring 313 can change the elastic force of the elastic element 4, thereby changing the travel of the valve core 3. For example, when the thickness of the adjusting ring 313 ( Figure 1 When the value of H is larger, the corresponding opening between the first oil port 101 and the second oil port 102 is larger when the valve core 3 moves downward in the valve body 1. Conversely, when the thickness of the adjusting ring 313 is thinner, the corresponding opening between the first oil port 101 and the second oil port 102 is smaller when the valve core 3 moves downward. Without the adjusting ring 313, the first oil port 101 and the second oil port 102 can be completely closed when the valve core moves downward.

[0064] Optionally, the valve body 1 includes a valve block 11 and a valve stem 12. One end of the valve stem 12 is located inside the valve block 11 and, together with the inner wall of the valve block 11, defines a first cavity 301 with the valve core 3. One end of the valve stem 12 is used to contact the end face of the valve core 3. The valve stem 12 is connected to the valve block 11 and is movable relative to the valve block 11 along its own axis.

[0065] In the above implementation, the valve block 11 provides a mounting base for the valve core 3, etc., and also serves to fix the buffer valve.

[0066] The valve stem 12 is used to adjust the size of the first chamber 301, thereby changing the size of the communication opening between the first oil port 101 and the second oil port 102 when the valve core moves upward. One end of the valve stem 12 is located inside the valve block 11 and protrudes beyond the inner wall surface of the valve block 11. When the width L of the adjustment gap between the end face of the valve stem 12 located inside the valve block 11 and the inner wall surface of the valve block 11 into which it is inserted is larger (that is, when the length of the valve stem 12 inserted into the valve block 11 is longer), the communication opening between the first oil port 101 and the second oil port 102 is smaller when the valve core 3 moves upward. Conversely, when the width L of the adjustment gap between the valve stem 12 and the valve core 3 is smaller (that is, when the length of the valve stem 12 inserted into the valve block 11 is shorter), the communication opening between the first oil port 101 and the second oil port 102 is larger when the valve core 3 moves upward. This is because the valve core 3 is limited by the valve stem 12 when it moves upward. When valve core 3 comes into contact with valve stem 12, it means that valve core 3 cannot continue to move upward.

[0067] In this embodiment, to facilitate the installation of the valve core 3, the valve block 11 is a detachable structure. The valve block 11 includes an end cap 111, a valve block body 112, and a valve sleeve 113. The valve block body 112 has a receiving hole 1120 that penetrates through the valve block body 112. The first oil port 101 and the second oil port 102 are respectively located in two adjacent side walls of the valve block body 112 and are both connected to the receiving hole 1120. The second oil port 102 is coaxially arranged with the receiving hole 1120.

[0068] The valve sleeve 113 is coaxially located in the receiving hole 1120 and connected to the valve block body 112. The end of the valve sleeve 113 facing the second oil port 102 is connected to the second oil port 102.

[0069] Figure 4 This is a structural schematic diagram of the valve sleeve, combined with... Figure 4 The outer wall of the valve sleeve 113 has a plurality of radial openings 1130 spaced apart along its circumference. The radial openings 1130 are used for communication with the first oil port 101.

[0070] Combination Figure 1 The cone 311 in the valve core 3 is movably located within the valve sleeve 113. A collar 312 is located outside the valve sleeve 113, with an outer diameter larger than the inner diameter of the valve sleeve 113, to limit the stroke of the valve core 3 during downward movement via the valve sleeve 113. An end cap 111 is located at the end of the receiving hole 1120 away from the second oil port 102 and partially extends into the receiving hole 1120. The end cap 111 is connected to the valve block body 112 by fasteners such as bolts. The valve stem 12 is threaded into the end cap 111.

[0071] Combination Figure 4 To facilitate the installation of the elastic element 4, the inner wall of the valve sleeve 113 has an annular limiting groove 1131. One end of the limiting groove 1131 is connected to the port of the valve sleeve 113 facing the first cavity 301, and the other end faces the second oil port 102. The elastic element 4 is located in the annular limiting groove 1131, and one end abuts against the bottom of the limiting groove 1131.

[0072] To improve sealing, a sealing ring is fitted between the end cap 111, which extends into the receiving hole 1120, and the valve block body 112. Simultaneously, a sealing ring is also fitted between the outer wall of the valve stem 12 and the end cap 111. The sealing ring can be an O-ring.

[0073] For example, the elastic element 4 is a telescopic spring.

[0074] Figure 5 for Figure 1 Top view, combined Figure 5 The valve block 11 has a rectangular block structure. The end cap 111 is connected to the valve block body 112 by bolts or other fasteners.

[0075] On the other hand, embodiments of this disclosure also provide a lifting control hydraulic system, such as Figure 6 As shown, the lifting control hydraulic system includes a proportional directional valve 100, a hydraulic motor 200, and any of the aforementioned buffer valves 300.

[0076] The inlet of the proportional directional valve 100 is used to connect to the oil pump, and the outlet of the proportional directional valve 100 is used to connect to the oil tank. The first working port of the proportional directional valve 100 is connected to the first port of the first working oil chamber 201, the first port of the second working oil chamber 202, and the first port of the third working oil chamber 203 of the hydraulic motor 200. The second working port of the proportional directional valve 100 is connected to the second port of the first working oil chamber 201.

[0077] The first working port of the proportional directional valve 100 is connected to its own inlet port, and the second working port of the proportional directional valve 100 is connected to its own outlet port (that is, the valve core of the proportional directional valve 100 is located at...). Figure 6 When the valve core of the proportional directional valve 100 is in the left position, the hydraulic motor 200 rotates forward. The first working port of the proportional directional valve 100 is connected to its own outlet, and the second working port of the proportional directional valve 100 is connected to its own inlet (that is, the valve core of the proportional directional valve 100 is located in the left position). Figure 6 When the hydraulic motor 200 is in the right position, it reverses. The second oil port of the second working oil chamber 202 is connected to the second oil port of the third working oil chamber 203.

[0078] The buffer valve 300 is connected between the second working port of the proportional directional valve 100 and the second working port of the second working chamber 202. The first port of the buffer valve 300 is connected to the second port of the first working chamber 201 and the second working port of the proportional directional valve 100. The second port of the buffer valve 300 is connected to the second port of the second working chamber 202, the second port of the third working chamber 203 and the first working port of the proportional directional valve 100.

[0079] The above-mentioned lifting control hydraulic system has the same beneficial effects as the aforementioned buffer valve, and will not be described in detail here.

[0080] Optionally, the lifting control hydraulic system also includes a hydraulic directional valve 400 and a pilot relief valve 500, both connected in the oil line between the outlet of the proportional directional valve 100 and the control port of the buffer valve 300. The first port of the hydraulic directional valve 400 is connected to the control port of the buffer valve 300, and the second port of the hydraulic directional valve 400 is connected to the inlet of the pilot relief valve 500. The control port of the hydraulic directional valve 400 is connected to the first port of the first working oil chamber 201, the second port of the second working oil chamber 202, and the third port of the third working oil chamber 203, respectively. The outlet of the pilot relief valve 500 is connected to the outlet of the proportional directional valve 100 and the oil tank, respectively, and the control port of the pilot relief valve 500 is connected to its own inlet. The spring setting pressure of the pilot relief valve 500 is greater than the spring setting pressure of the hydraulic directional valve 400.

[0081] In this embodiment, during rope release, when the pressure in the first chamber 301 of the buffer valve is greater than the set pressure of the hydraulic directional valve 400 but less than the set pressure of the pilot relief valve 500, the hydraulic directional valve 400 opens and the pilot relief valve 500 closes, ensuring that the pressure in the first chamber 301 is not lower than the set pressure of the hydraulic directional valve 400. Conversely, when the pressure in the first chamber 301 is greater than the set pressure of the pilot relief valve 500, both the hydraulic directional valve 400 and the pilot relief valve 500 open, connecting the first chamber 301 to the oil tank via both valves. However, the pressure in the first chamber 301 remains at the set pressure of the pilot relief valve 500. Therefore, the pressure in the first chamber 301 of the buffer valve 300 can be limited to a relatively low level.

[0082] For example, the set pressure of the hydraulic directional valve 400 is 3.6 MPa. The set pressure of the pilot relief valve 500 is 4.5 MPa. The above set pressures can be flexibly set according to the operating conditions.

[0083] Optionally, the lifting control hydraulic system further includes a first switching valve 600 and a second switching valve 700. The first switching valve 600 is connected between the first oil port of the first working oil chamber 201 and the first oil port of the second working oil chamber 202. The first switching valve 600 is configured to: connect the first oil port of the second working oil chamber 202 to the first oil port of the first working oil chamber 201 in one direction when the hydraulic motor 200 is rotating in reverse; and connect the first oil port of the second working oil chamber 202 to the first oil port of the first working oil chamber 201 when the hydraulic motor 200 is rotating in the forward direction and the oil pressure at the first oil port of the first working oil chamber 201 is higher than a first threshold.

[0084] The second switching valve 700 is connected between the first oil port of the second working oil chamber 202 and the first oil port of the third working oil chamber 203 of the motor. The second switching valve 700 is configured to: when the hydraulic motor 200 reverses, connect the first oil port of the third working oil chamber 203 to the first oil port of the first working oil chamber 201 through the first switching valve 600; when the hydraulic motor 200 rotates forward and the oil pressure at the first oil port of the first working oil chamber 201 reaches the second threshold high pressure, connect the first oil port of the third working oil chamber 203 of the motor to the first oil port of the second working oil chamber 202. The second threshold is greater than the first threshold.

[0085] In the above implementation, the first switching valve 600 and the second switching valve 700 are configured such that the number of working oil chambers of the hydraulic motor when driving the winch to lift the load varies depending on the gravity of the lifting load. Under certain working conditions, only one working oil chamber or two or three working oil chambers can work at the same time.

[0086] For example, under heavy load, the first switching valve 600 and the second switching valve 700 can be used to ensure that all three working chambers of the hydraulic motor receive oil synchronously. Under light load, the first switching valve 600 and the second switching valve 700 can be used to ensure that only one working chamber of the hydraulic motor receives oil. Under medium load, the first switching valve 600 and the second switching valve 700 can be used to ensure that two working chambers of the hydraulic motor receive oil.

[0087] In this embodiment of the present disclosure, the first switching valve 600 includes a one-way sub-valve 601 and a reversing sub-valve 602. The inlet of the one-way sub-valve 601 is connected to the first port of the second working oil chamber 202, and the outlet of the one-way sub-valve 601 is also connected to the first port of the first working oil chamber 201. The first port of the reversing sub-valve 602 is connected to the first port of the first working oil chamber 201, the second port of the reversing sub-valve 602 is connected to the first port of the second working oil chamber 202, the pilot port of the reversing sub-valve 602 is connected to the first port of the reversing sub-valve 602, and the control port of the reversing sub-valve 602 is connected to the second port of the second working oil chamber 202.

[0088] The second switching valve 700 has the same structure as the first switching valve 600, and its connection method is similar to that of the first switching valve 600. For details, please refer to [link / reference needed]. Figure 6 This will not be elaborated upon here.

[0089] Optionally, the lifting control hydraulic system further includes a first check valve 1100, which is connected between the second oil port of the third working oil chamber 203 and the first oil port of the third working oil chamber 203. The oil inlet of the first check valve 1100 is connected to the second oil port of the third working oil chamber 203 and the second oil port of the second working oil chamber 202, respectively, and the oil outlet of the first check valve 1100 is connected to the first oil port of the third working oil chamber 203.

[0090] In the above implementation, the first check valve 1100 allows the hydraulic motor to drive the hoisting winch to lift the load. When the hydraulic motor is only operating from the first working oil chamber 201, the oil exits from the second port of the first working oil chamber 201. A portion of the oil passes through the buffer valve 300 and the first check valve 1100 into the first port of the third working oil chamber 203, thus replenishing the oil in the third working oil chamber 203. This allows the oil to carry away heat from the third working oil chamber 203 and lubricate it. Simultaneously, a portion of the oil entering the third working oil chamber 203 also passes through the check sub-valve 601 of the first switching valve 600 into the first port of the second working oil chamber 202 to replenish the oil in the second working oil chamber 202, allowing the oil to simultaneously carry away heat from the second working oil chamber 202 and lubricate it.

[0091] Optionally, the lifting control hydraulic system further includes a second check valve 1200 and a third check valve 1300. The second check valve 1200 is connected between the first working port of the proportional directional valve 100 and the first port of the first working chamber 201. The inlet of the second check valve 1200 is connected to the first working port of the proportional directional valve 100, and the outlet of the second check valve 1200 is connected to the first port of the first working chamber 201, the outlet of the check sub-valve 601 in the first switching valve 600, and the first port of the reversing sub-valve 602 in the first switching valve 600.

[0092] The third check valve 1300 is connected between the first working port of the proportional directional valve 100 and the second port of the third working oil chamber 203 and the second port of the buffer valve 300. The inlet of the third check valve 1300 is connected to the second port of the buffer valve 300, the second port of the third working oil chamber 203 and the second port of the second working oil chamber 202, respectively. The outlet of the third check valve 1300 is connected to the second working port of the proportional directional valve 100 and the outlet of the second check valve 1200.

[0093] In the above implementation, the second check valve 1200 is used to restrict the communication between the first working port of the proportional directional valve 100 and the first working chamber 201 to be unidirectional. The third check valve 1300 is used to restrict the communication between the buffer valve 300 and the first working port of the proportional directional valve 100 to be unidirectional.

[0094] Optionally, the lifting control hydraulic system also includes a balance valve 800. The inlet of the balance valve 800 is connected to the first port of the first working oil chamber 201 and the outlet of the second check valve 1200. The outlet of the balance valve 800 is connected to the inlet of the third check valve 1300, the second port of the buffer valve 300, the second port of the second working oil chamber 202, and the second port of the third working oil chamber 203. The pilot port of the balance valve 800 is connected to the second port of the first working oil chamber 201 and the first port of the buffer valve 300. The control port of the balance valve 800 is connected to its own outlet.

[0095] In the above implementation, the arrangement of the balance valve 800 allows for dynamic control of the oil flow in the return oil circuit when the hydraulic motor drives the hoisting winch to release the rope, preventing the load from falling uncontrollably. That is, by setting the valve's opening pressure, a certain back pressure is provided during descent, ensuring the load descends smoothly at a controllable speed and avoiding the "free fall" phenomenon. Combined with... Figure 6 During rope release, the pilot port of the balance valve 800 is connected to the second port of the first working oil chamber 201 and the first port of the buffer valve 300. This means that the oil from the pump outlet enters the pilot port of the balance valve 800 after passing through the proportional directional valve 100. The oil overcomes the spring and load pressure of the balance valve 800 to open. The oil flowing out from the first port of the first working oil chamber 201, the first port of the second working oil chamber 202, and the first port of the third working oil chamber 203 enters the balance valve 800 and flows back to the oil tank through it. When the rope release speed suddenly increases, according to Bernoulli's principle, as the flow rate increases, the pressure drop across the valve port of the balance valve 800 increases, causing the oil pressure at the inlet of the balance valve 800 to rise, i.e., the load pressure increases. The valve core of the balance valve 800 moves towards the closing direction, reducing the valve opening and suppressing acceleration. When the rope release speed decreases, the flow rate decreases, the load pressure decreases, and the valve port of the balance valve 800 increases to maintain a constant speed. That is, the balance valve dynamically controls the valve port opening through the negative feedback adjustment of the return oil back pressure, so as to achieve a constant speed decrease of the load.

[0096] Optionally, the lifting control hydraulic system also includes a safety valve 900. The safety valve 900 is connected between the oil inlet of the balance valve 800 and the second oil port of the third working oil chamber 203. The oil inlet of the safety valve 900 is connected to the first oil port of the first working oil chamber 201 and the oil inlet of the balance valve 800. The oil outlet of the safety valve 900 is connected to the oil inlet of the third check valve 1300, the second oil port of the buffer valve 300, the second oil port of the second working oil chamber 202, and the second oil port of the third working oil chamber 203. The control oil port of the safety valve 900 is connected to its own oil outlet, and the pilot oil port of the safety valve 900 is connected to its own oil inlet.

[0097] In the above implementation, the safety valve 900 is arranged to limit the oil pressure in the return oil circuit and protect the entire hydraulic circuit.

[0098] The following is a brief description of the working process of the lifting control hydraulic system provided in the embodiments of this disclosure: (1) Light load rope winding condition of hydraulic motor: Before the rope is retracted, there is no pressure at the first oil port 101 and the second oil port 102 of the buffer valve 300. The valve core 3 is in the upper position under the action of the spring force. The first oil port 101 of the buffer valve ( Figure 6 The buffer valve's port A) and the second oil port 102 ( Figure 6 The buffer valve (port B) is connected to the buffer valve, and the buffer valve remains fully open.

[0099] When the hydraulic motor is lightly loaded and winding the rope, the proportional directional valve 100 operates in the left position, P→A, B→T2. The pressurized oil at port P passes through the first working port A of the proportional directional valve 100 and the second check valve 1200 before entering the first port of the first working oil chamber 201 of the hydraulic motor (port A of the hydraulic motor in the figure). Because the working pressure at port A of the hydraulic motor is low, both the first switching valve 600 and the second switching valve 700 remain in their initial state, i.e., they operate in the right position under the action of spring force, and ports A and B of both the first switching valve 600 and the second switching valve 700 are disconnected.

[0100] The first working oil chamber 201 of the hydraulic motor is operational. The oil in the first working oil chamber 201 returns to the oil tank after passing through the second oil port of the first working oil chamber 201 (port D of the hydraulic motor in the figure) and the second working oil port B of the proportional directional valve 100. The second working oil chamber 202 and the third working oil chamber 203 of the hydraulic motor do not participate in the operation. The oil remaining in the second working oil chamber 202 and the third working oil chamber 203 flows out through their respective second oil ports (ports E and F of the hydraulic motor in the figure), and forms an internal circulation with the first oil port of the second working oil chamber 202 (port C of the hydraulic motor in the figure) and the first oil port of the third working oil chamber 203 (port B of the hydraulic motor in the figure) through the first check valve 1100, the check sub-valve 601 of the first switching valve 600, and the first oil port of the second working oil chamber 202 (port C of the hydraulic motor in the figure) and the first oil port of the third working oil chamber 203 (port B of the hydraulic motor in the figure).

[0101] At this time, the oil flowing out of the second port of the first working oil chamber 201 of the hydraulic motor 200 passes through the first port of the buffer valve 300 (i.e., port A of the buffer valve in the figure) and the damping orifice 3200 before entering the first chamber 301 between the valve core 3 and the end cover 111. Under light load, the inlet pressure of the three chambers of the hydraulic motor is less than the set pressure of the hydraulic directional valve 400 (3.6 MPa). Under the action of the spring force, the hydraulic directional valve 400 remains in the upper position, that is, the first port (i.e., P1) and the first port (i.e., P2) of the hydraulic directional valve 400 are disconnected.

[0102] Since there is no oil flow at the control port of buffer valve 300 (i.e., port X of the buffer valve in the figure), the pressure in the first chamber 301 is the same as the pressure at port A of buffer valve 300. Under the action of the spring force, the valve core 3 moves upward and remains fully open.

[0103] (2) Hydraulic motor in mid-load rope winding condition: Before the rope is retracted, there is no pressure at the first oil port 101 and the second oil port 102 of the buffer valve 300. The valve core 3 is in the upper position under the action of the spring force. The first oil port 101 and the second oil port 102 of the buffer valve are interconnected, and the buffer valve remains fully open.

[0104] When the hydraulic motor 200 is engaged with a loaded rope, the proportional directional valve 100 operates in the left position, P→A, B→T2. The pressurized oil at port P passes through the first working port A of the proportional directional valve 100 and the second check valve 1200 before entering the first port of the first working chamber 201 of the hydraulic motor (port A in the diagram). Since the hydraulic motor cannot drive the load when only port A is operating, the pressure at port A of the hydraulic motor increases. This increases the pressure at the control port of the reversing sub-valve 602 of the first switching valve 600, overcoming the spring force of the first switching valve 600, and connecting port A and port B of the first switching valve 600. The pressurized oil then enters the first port of the second working chamber 202 of the hydraulic motor (port B in the diagram), and both the first and second working chambers 201 of the hydraulic motor operate simultaneously.

[0105] The hydraulic fluid from port D of the hydraulic motor 200 returns to the oil tank after passing through port B of the proportional directional valve 100. A small portion of the oil from the second port of the second working oil chamber 202 (port E of the hydraulic motor in the figure) and the second port of the third working oil chamber 203 (port F of the hydraulic motor in the figure) of the hydraulic motor 200 forms an internal circulation with port C of the hydraulic motor through the first check valve 1100, and replenishes the oil leaked during the circulation process; most of the oil needs to pass through port B → port A of the buffer valve 300, and then return to the oil tank from port B of the proportional directional valve 100.

[0106] At this time, the hydraulic oil from port D of the hydraulic motor passes through port A of buffer valve 300 and damping orifice 3200 before entering the first chamber 301. Under medium load, the pressure in the three working chambers of the hydraulic motor is greater than the set pressure of hydraulic directional valve 400 (3.6 MPa). Under the action of spring force, hydraulic directional valve 400 switches to the lower position, and ports P1 and P2 of hydraulic directional valve 400 are connected. However, because the pressure (return back pressure) at port B of proportional directional valve 100 is less than the set pressure of pilot relief valve 500 (4.5 MPa), pilot relief valve 500 remains closed. Although the buffer valve 300 remains fully open at this time, unlike the light load rope winding condition, the oil flow direction of the buffer valve 300 is B port → A port. That is, the buffer valve 300 adapts from the oil replenishment state (A → B) of the hydraulic motor in the light load rope winding condition to the oil return state (B → A) of the medium load rope winding condition.

[0107] (3) Heavy-load rope winding condition of hydraulic motor: Before the rope is retracted, there is no pressure at the first oil port 101 and the second oil port 102 of the buffer valve. The valve core 3 is in the upper position under the action of the spring force. The first oil port 101 of the buffer valve (that is...) Figure 6 The buffer valve's port A) and the second oil port 102 (that is... Figure 6 The buffer valve (port B) is connected to the buffer valve, and the buffer valve remains fully open.

[0108] When the hydraulic motor is under heavy load and winding the rope, the proportional directional valve 100 operates in the left position, P→A, B→T2. The pressurized oil at port P passes through the first working port A of the proportional directional valve 100 and the second check valve 1200 before entering ports A and B of the hydraulic motor. Since there is pressurized oil at ports A and B of the hydraulic motor, it is still not enough to drive the load. Therefore, the pressure at ports A and B of the hydraulic motor continues to rise, overcoming the spring force of the control port of the reversing sub-valve of the second switching valve 700, and the pressurized oil enters port C of the hydraulic motor 200. Oil enters all three working chambers of the hydraulic motor 200 simultaneously.

[0109] The hydraulic fluid from port D of the hydraulic motor returns to the oil tank after passing through port B of the proportional directional valve 100. All the hydraulic fluid flowing out from ports E and F of the hydraulic motor passes through port B → port A of the buffer valve 300, and also returns to the oil tank from port B of the proportional directional valve 100. At this time, the working state of the buffer valve is the same as that of the hydraulic motor during rope winding, which will not be described further here.

[0110] (4) Hydraulic motor rope release operation: Before releasing the rope, there is no pressure on the first oil port 101 and the second oil port 102 of the buffer valve. The valve core 3 is in the upper position under the action of the spring force. The first oil port 101 and the second oil port 102 of the buffer valve are interconnected, and the buffer valve remains fully open.

[0111] When the hydraulic motor releases the rope, the proportional directional valve 100 operates in the right position, P→B, A→T1.

[0112] The pressurized oil from port P of the proportional directional valve 100 passes through port B of the proportional directional valve 100 and then enters port D of the hydraulic motor. Port D of the hydraulic motor pressurizes and opens the balance valve 800. Oil flowing from ports A, B, and C of the hydraulic motor (the simultaneous output from three working chambers is necessary to release residual pressure in each chamber via return oil) passes sequentially through the one-way sub-valve circuit of the first switching valve 600, the one-way sub-valve circuit of the second switching valve 700, the balance valve 800, the third one-way valve 1300, and port A of the proportional directional valve 100 before returning to the oil tank. At this point, when the flow rate through the proportional directional valve 100 is the same, because only port D of the hydraulic motor receives oil, compared to when ports A, B, and C of the hydraulic motor receive oil during rope winding, the rope release speed of the hydraulic motor can reach three times the rope winding speed, resulting in higher efficiency.

[0113] The pressure oil from port P of the proportional directional valve 100 passes through port B of the proportional directional valve 100, then sequentially through ports A→B of the buffer valve 300 and the third check valve 1300, before returning to the oil tank from port A of the proportional directional valve 100. The buffer valve 300 effectively diverts the oil from port B of the proportional directional valve 100 to dynamically control the flow and pressure entering port D of the hydraulic motor.

[0114] When the rope is released, the hydraulic motor pressurizes at port D to open the balance valve 800. The oil output from port B of the proportional directional valve 100 passes through port A of the buffer valve 300 and the damping hole 3200 in sequence before entering the first chamber 301. The pressure in the first chamber 301 overcomes the elastic force of the elastic element 4 in the buffer valve, causing the valve core 3 to move downward to the limit position, that is, the connection opening of the buffer valve 300 changes from the fully open state to the minimum connection opening state.

[0115] It is important to note that, in order to change the size of the buffer valve's opening, the adjusting ring 313 of different thicknesses can be selected according to the operating conditions. By selecting adjusting ring 313 of different thicknesses, the minimum value of the buffer valve's opening can be changed. When the thickness of the adjusting ring 313 is larger, the opening between the first oil port 101 and the second oil port 102 is larger in the minimum state. At this time, more oil flows from port B of the proportional directional valve 100 through the buffer valve 300, resulting in a smaller flow rate from port B of the proportional directional valve 100 into port D of the hydraulic motor, and a slower rope release speed. Conversely, when the thickness of the adjusting ring 313 is smaller, the opening between the first oil port 101 and the second oil port 102 (i.e., the valve port) is smaller in the minimum state. At this time, less oil flows from port B of the proportional directional valve 100 through the buffer valve 300, resulting in a larger flow rate from port B of the proportional directional valve 100 into port D of the hydraulic motor, and a faster rope release speed.

[0116] Under certain operating conditions, the pressure at ports A, B, and C of the hydraulic motor will exceed the set pressure of the hydraulic directional valve 400 and the set pressure of the pilot relief valve 500 during rope release. The hydraulic directional valve 400 reverses, operating in the lower position (P1→P2). The pilot relief valve 500 opens (P→T). The oil at port B of the proportional directional valve 100 passes through port A of the buffer valve 300, the damping orifice 3200, port X of the buffer valve, the hydraulic directional valve P1→P2, and the pilot relief valve 500 P→T before returning to the oil tank. The oil pressure in the first chamber 301 of the buffer valve 300 is limited to the set pressure of the pilot relief valve 500. At this time, due to the throttling effect of the damping orifice 3200, the upward hydraulic pressure of the annular cavity at the adjusting ring 313 is greater than the downward hydraulic pressure of the first cavity 301, causing the valve core 3 to continue to move upward. The opening of the buffer valve becomes larger, and the flow rate of the oil from port B of the proportional directional valve 100 through the buffer valve 300 increases, thereby reducing the flow rate and pressure of the oil entering port D of the hydraulic motor and preventing the speed from being too fast when releasing the rope under heavy load.

[0117] Meanwhile, to further modify the connection opening of the buffer valve, the position of the adjusting valve stem 12 can be flexibly set according to the operating conditions to adjust the size of the connection opening between port A and port B of the buffer valve. When the adjustment gap is larger, the connection opening between port A and port B of the buffer valve is smaller when the valve core 3 moves upward; conversely, when the adjustment gap is smaller, the connection opening between port A and port B of the buffer valve is larger when the valve core 3 moves, thereby adjusting the oil flow rate of the buffer valve 300.

[0118] Alternatively, if a further increase in rope winding speed is required, while maintaining a constant rope unwinding speed at the same flow rate in the proportional directional valve 100, this can be achieved by thinning the adjusting ring 313. This means that during unwinding, the oil at port B of the proportional directional valve 100 is diverted back through the buffer valve 300, instead of entering port D of the hydraulic motor. In short, during rope unwinding, the buffer valve can dynamically adjust the size of the connection opening according to the load size to regulate the flow rate and pressure of the oil entering port D of the hydraulic motor from port B of the proportional directional valve 100, thereby controlling the rope unwinding speed.

[0119] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A buffer valve for a hydraulic motor, characterized in that, The buffer valve (300) is used to connect to the hydraulic motor (200) in the lifting control hydraulic system. The hydraulic motor (200) includes a first working oil chamber (201), a second working oil chamber (202) and a third working oil chamber (203). The buffer valve (300) includes a valve body (1), a valve core (3), and an elastic element (4); The valve body (1) has a first oil port (101), a second oil port (102) and a control oil port (103). The first oil port (101) of the valve body (1) is used to connect to the second oil port of the first working oil chamber (201). The second oil port (102) of the valve body (1) is used to connect to the second oil port of the second working oil chamber (202) and the second oil port of the third working oil chamber (203) respectively. The control oil port (103) is used to selectively connect to the oil tank. The valve core (3) is movably located in the valve body (1) and at the junction of the first oil port (101) and the second oil port (102) of the valve body (1). A first cavity (301) is formed between one end face of the valve core (3) and the valve body (1). The first cavity (301) is connected to the control oil port (103). An annular gap (3001) is defined between the outer peripheral wall of the end of the valve core (3) away from the first cavity (301) and the valve body (1). The valve core (3) has a throttling channel (302), one end of which is connected to the first cavity (301), and the other end of which is connected to the annular gap (3001). The elastic element (4) is located inside the annular gap (3001) and is sleeved outside the valve core (3). One end of the elastic element (4) abuts against the inner wall of the valve body (1), and the other end of the elastic element (4) abuts against the outer wall of the valve core (3). The valve core (3) is configured to move under the action of the first cavity (301) and the elastic element (4) to change the size of the communication opening between the first oil port (101) and the second oil port (102).

2. The buffer valve according to claim 1, characterized in that, The valve core (3) includes an outer ring sleeve (31) and an inner valve core (32). The inner valve core (32) is located inside the end of the outer ring sleeve (31) facing the first cavity (301). The outer circle of the inner valve core (32) is in clearance fit with and connected to the inner circumferential wall of the outer ring sleeve (31). The inner valve core (32) has an axial channel (320) and a damping hole (3200). The axial channel (320) extends in the same direction as the axis of the outer ring sleeve (31). The damping hole (3200) penetrates the side wall of the inner valve core (32) and communicates with the middle part of the axial channel (320). The axial channel (320) communicates with the first cavity (301). The outer ring sleeve (31) has a connecting hole (303) in its side wall. The connecting hole (303) is located on the side of the damping hole (3200) away from the first cavity (301) and is connected to the annular gap (3001). The connecting hole (303) is connected to the damping hole (3200) through the gap between the inner valve core (32) and the outer ring sleeve (31).

3. The buffer valve according to claim 2, characterized in that, The axial channel (320) includes a first hole segment (3201) and a second hole segment (3202) connected to each other along its own axial direction. The second hole segment (3202) is located between the first hole segment (3201) and the first cavity (301). The inner diameter of the first hole segment (3201) is not less than the inner diameter of the second hole segment (3202). The valve core (3) also includes a ball head (34), which is located in the first hole section (3201) and has a radius greater than the inner diameter of the second hole section (3202).

4. The buffer valve according to claim 3, characterized in that, The first oil port (101) and the second oil port (102) are respectively located in two adjacent side walls of the valve body (1); The outer ring sleeve (31) includes a cone (311) and a collar (312). The larger outer diameter end of the cone (311) is connected to the first end of the collar (312). The smaller outer diameter end of the cone (311) faces the second oil port (102) and is coaxially arranged with the second oil port (102). The second end of the collar (312) faces the first cavity (301), and the outer wall of the collar (312) near the second end has an annular step (3120). The elastic element (4) is sleeved on the outside of the cone (311), and one end abuts against the step surface of the step (3120) facing the cone (311).

5. The buffer valve according to claim 4, characterized in that, The outer ring sleeve (31) also includes an adjusting ring (313), which is sleeved outside the sleeve (312). The two ends of the adjusting ring (313) along the axial direction are respectively clamped between the step surface of the step (3120) facing the cone (311) and the end of the elastic element (4) facing the first cavity (301).

6. The buffer valve according to any one of claims 1-5, characterized in that, The valve body (1) includes a valve block (11) and a valve stem (12). One end of the valve stem (12) is located inside the valve block (11) and together with the inner wall of the valve block (11), it defines the first cavity (301) with the valve core (3). The valve stem (12) is connected to the valve block (11) and can move relative to the valve block (11) along its own axis.

7. A lifting control hydraulic system, characterized in that, The lifting control hydraulic system includes a proportional directional valve (100), a hydraulic motor (200), and a buffer valve (300) as described in any one of claims 1-6. The inlet of the proportional directional valve (100) is used to connect to the oil pump, and the outlet of the proportional directional valve (100) is used to connect to the oil tank. The first working oil port of the proportional directional valve (100) is connected to the first oil port of the first working oil chamber (201), the first oil port of the second working oil chamber (202), and the first oil port of the third working oil chamber (203) of the hydraulic motor (200). The second working port of the proportional directional valve (100) is connected to the second port of the first working oil chamber (201). When the first working port of the proportional directional valve (100) is connected to its own inlet and the second working port of the proportional directional valve (100) is connected to its own outlet, the hydraulic motor (200) rotates in the forward direction. When the first working port of the proportional directional valve (100) is connected to its own outlet and the second working port of the proportional directional valve (100) is connected to its own inlet, the hydraulic motor (200) reverses. The second oil port of the second working oil chamber (202) is connected to the second oil port of the third working oil chamber (203); The buffer valve (300) is connected between the second working port of the proportional directional valve (100) and the second port of the second working chamber (202). The first port (101) of the buffer valve (300) is connected to the second port of the first working chamber (201) and the second working port of the proportional directional valve (100). The second port of the buffer valve (300) is connected to the second port of the second working chamber (202), the second port of the third working chamber (203), and the first working port of the proportional directional valve (100).

8. The lifting control hydraulic system according to claim 7, characterized in that, The lifting control hydraulic system also includes a hydraulic directional valve (400) and a pilot relief valve (500), both of which are connected to the oil passage between the oil outlet of the proportional directional valve (100) and the oil tank. The first port of the hydraulic directional valve (400) is connected to the control port of the buffer valve (300), the second port of the hydraulic directional valve (400) is connected to the inlet of the pilot relief valve (500), and the control port of the hydraulic directional valve (400) is connected to the first port of the first working oil chamber (201), the second port of the second working oil chamber (202), and the third port of the third working oil chamber (203), respectively. The oil outlet of the pilot relief valve (500) is connected to the oil outlet of the proportional directional valve (100) and the oil tank, respectively, and the control oil port of the pilot relief valve (500) is connected to its own oil inlet.

9. The lifting control hydraulic system according to claim 8, characterized in that, The lifting control hydraulic system also includes a first switching valve (600) and a second switching valve (700). The first switching valve (600) is connected between the first oil port of the first working oil chamber (201) and the first oil port of the second working oil chamber (202). The first switching valve (600) is configured to: connect the first oil port of the second working oil chamber (202) to the first oil port of the first working oil chamber (201) when the hydraulic motor (200) is in reverse rotation; and connect the first oil port of the second working oil chamber (202) to the first oil port of the first working oil chamber (201) when the hydraulic motor (200) is in forward rotation and the oil pressure at the first oil port of the first working oil chamber (201) is higher than a first threshold. The second switching valve (700) is connected between the first oil port of the second working oil chamber (202) and the first oil port of the third working oil chamber (203) of the motor. The second switching valve (700) is configured to: when the hydraulic motor (200) reverses, connect the first oil port of the third working oil chamber (203) to the first oil port of the first working oil chamber (201) through the first switching valve (600); when the hydraulic motor (200) rotates forward and the oil pressure at the first oil port of the first working oil chamber (201) reaches the second high pressure threshold, connect the first oil port of the third working oil chamber (203) of the motor to the first oil port of the second working oil chamber (202).

10. The lifting control hydraulic system according to claim 9, characterized in that, The lifting control hydraulic system further includes a first check valve (1100), which is connected between the second oil port of the third working oil chamber (203) and the first oil port of the third working oil chamber (203). The inlet of the first check valve (1100) is connected to the second oil port of the third working oil chamber (203) and the second oil port of the second working oil chamber (202), and the outlet of the first check valve (1100) is connected to the first oil port of the third working oil chamber (203).

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