Control unit, hydraulic system and working machine

Abstract

A control unit, a hydraulic system and an operation machine, wherein the control unit has a port P, a port T, a port B as well as a pressure reducing valve (k1), a sequence valve (k2) and an unloading damper (k3) connected between the port P and the port B, and the control unit is configured so that: in an initial state, pressure oil conveyed from the port P is delivered to the port T and the port B simultaneously via the unloading damper (k3); in a loaded state, pressure oil conveyed from the port P can be delivered to the port B from an inlet side of the unloading damper (k3), and the port B is disconnected from the unloading damper (k3); the control unit further comprises a first pilot oil path (d1) and a second pilot oil path (d2), wherein, the first pilot oil path (d1) is configured to control the operation of the sequence valve (k2) to switch the control unit between the initial state and the loaded state, and the second pilot oil path (d2) is configured to control the operation of pressure reducing valve (k1) to control the input flow rate from the port P, therefore, on-demand opening can be achieved, pressure reduction and overflow are carried out first, and then sequential opening is carried out, thereby solving the problem of jittering of a winch system in a winch micro-action working condition.

Description

[0001] The present application claims the priority of the Chinese patent application with the application number of 202310098584.X, filed with the CNIPA on January 31, 2023, which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present application relates to the technical field of hydraulics, and specifically relates to a control unit, a hydraulic system and an operation machine.BACKGROUND

[0003] At present, in engineering machinery, cartridge valves with a function of sequential pressure reduction and overflow, which are widely used on winch balance valves, usually work in a way of carrying out sequential opening first and then carrying out pressure reduction and overflow. This type of cartridge valves have high requirements for the size of the unloading groove and the cooperation between the valve spool and the valve sleeve. When a winch is in a micro-action working condition during lifting, winch jittering often occurs, which seriously adversely affects the lifting precision and safety.

[0004] In order to solve the problem of winch jittering in a micro-action working condition of a winch lifting apparatus, it is thus necessary to research a new valve group that can reduce the jittering of a winch using such a valve group in a micro-action working condition.SUMMARY TECHNICAL PROBLEM

[0005] The objective of the present application is to solve the problem of winch jittering in a micro-action working condition of a winch lifting apparatus. In view of this, embodiments of the present application are dedicated to providing a control unit, a hydraulic system and an operation machine, wherein the control unit can reduce the jittering of a winch using such a control unit in a micro-action working condition.TECHNICAL SOLUTION

[0006] In order to solve the above problem, in a first aspect, the present application provides a control unit, having a port P in communication with a pressure source, a port T in communication with an oil tank and a port B in communication with an execution unit, wherein, the control unit includes a pressure reducing valve, a sequence valve and an unloading damper connected between the port P and the port B, and the control unit is configured so that: in an initial state, pressure oil conveyed from the port P is delivered to the port T and the port B simultaneously via the unloading damper; in a loaded state, pressure oil conveyed from the port P can be delivered to the port B from an inlet side of the unloading damper, and the port B is disconnected from the unloading damper; the control unit further comprises a first pilot oil path and a second pilot oil path, wherein, the first pilot oil path is configured to control the operation of the sequence valve to switch the control unit between the initial state and the loaded state, and the second pilot oil path is configured to control the operation of pressure reducing valve to control the input flow rate from the port P.

[0007] In an embodiment, two ends of the first pilot oil path are connected to a control end of the sequence valve and an inlet of the unloading damper respectively, and / or, two ends of the second pilot oil path are connected to a control end of the pressure reducing valve and the inlet of the unloading damper respectively.

[0008] In an embodiment, a housing of the pressure reducing valve and a housing of the sequence valve form an integral valve body, with the port P, the port T, and the port B formed on the valve body.

[0009] In an embodiment, a valve spool of the pressure reducing valve and a valve spool of the sequence valve form an integral main valve spool, with the unloading damper formed on the main valve spool, the valve body has a valve chamber, the main valve spool is slidably arranged in the valve chamber, the port P, the port T and the port B penetrate a wall of the valve body and are in communication with the valve chamber.

[0010] In an embodiment, the main valve spool is provided with a central oil passage extending along an axial direction, the unloading damper comprises a damping hole penetrating the wall of the main valve spool to be in communication with the central oil passage, the main valve spool is further provided with a pressure oil port penetrating the wall of the main valve spool to be in communication with the central oil passage: in the initial state, the port P is in communication with both the port T and the port B simultaneously through the pressure oil port, the central oil passage, and then the damping hole.

[0011] In an embodiment, the main valve spool is provided with a pilot oil hole penetrating the wall of the main valve spool to be in communication with the central oil passage, in the loaded state, the damping hole is disconnected from the port B, the port P is in communication with the port B, wherein, the pressure oil conveyed from the port P via the pressure oil port flows along the central oil passage to the pilot oil hole, which forms the first pilot oil path, the main valve spool can be moved under the action of the first pilot oil path, so that the pilot oil hole becomes in communication with the port B, thereby switching the control unit from the initial state to the loaded state.

[0012] A second aspect of the present application provides a hydraulic system, which includes the above-mentioned control unit and an execution unit, wherein, the port B is in communication with the execution unit.

[0013] In an embodiment, the execution unit includes a motor and a braker for braking the motor, the port B is in communication with a brake cylinder of the braker, the hydraulic system further includes a first pipeline and a second pipeline, the motor has two oil ports, one of the two oil ports is connected to a first main pressure oil port through the first pipeline, and the other of the two oil ports is connected to a second main pressure oil port through the second pipeline, the port P is in communication with one of the first pipeline and the second pipeline that has a higher pressure.

[0014] In an embodiment, the hydraulic system further includes a balance valve, the balance valve is mounted on one of the first pipeline and the second pipeline, and a control end of the balance valve is connected to the other of the first pipeline and the second pipeline.

[0015] A third aspect of the present application provides an operation machine, which includes the above-mentioned hydraulic system.BENEFICIAL EFFECTS

[0016] By means of the above settings, an unloading damper is arranged between the pressure reducing valve and the sequence valve in the present application, and it is configured so that in the initial state, pressure oil conveyed from the port P is in communication with the port B and the port T respectively via the unloading damper to achieve pressure reduction and overflow unloading, and in the loaded state, the port B and the port P bypass the unloading damper and are in direct communication with each other to provide the required pressure for the execution unit. The present application also controls the flow rate from the port P by controlling the pressure reducing valve through the first pilot oil path, and controls the operation of the sequence valve to switch between the initial state and the loaded state by utilizing the second pilot oil path, therefore, on-demand opening can be achieved, pressure reduction and overflow are carried out first, and then sequential opening is carried out, in this way, even if the manufacture precision of the control unit is relatively low, the housing still can guarantee the normal operation of the braker connected with the port B, thereby preventing occurrence of abnormal opening of the braker in the winch system caused by the influence of manufacture precision of the control unit, and thus completely solving the problem of jittering of the winch system in a winch micro-action working condition.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Fig. 1 is a schematic diagram of the working principle of a control unit provided by an embodiment of the present application; Fig. 2 is a structural schematic diagram of a control unit provided by an embodiment of the present application; Fig. 3 is a structural schematic diagram of the main valve spool in Fig. 2; Fig. 4 is schematic diagram of a hydraulic system provided by an embodiment of the present application. EMBODIMENTS OF THE PRESENT INVENTION

[0018] Technical solutions of the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Apparently, the described embodiments only represent a part of the embodiments of the present application, not all of them. Based on the embodiments described in the present application, all other embodiments obtainable by those ordinarily skilled in the art without expenditure of creative labor fall within the scope of protection of the present application.

[0019] In order for the present application to be understood more conveniently, the present application is described below with reference to specific embodiments in conjunction with accompanying drawings.

[0020] In the first aspect, referring to Figs. 1 to 3 as shown, the present application provides a control unit, which has a port P in communication with a pressure source, a port T in communication with an oil tank and a port B in communication with an execution unit, and the control unit includes a pressure reducing valve k1, a sequence valve k2 and an unloading damper k3 connected between the port P and the port B, and the control unit is configured so that: in an initial state, pressure oil conveyed from the port P is delivered to the port T and the port B simultaneously via the unloading damper k3, in an embodiment as shown in Fig.1, in the initial state, the pressure oil conveyed from the port P is delivered to the port T via the unloading damper k3 and through a second oil path L2, at the same time, is delivered to the port B via the unloading damper k3 and through a third oil path L3; in a loaded state, pressure oil conveyed from the port P can be delivered to the port B from an inlet side of the unloading damper k3, and the port B is disconnected from the unloading damper k3, wherein the pressure oil conveyed from the port P flows along a first oil path L1 to the port B; the control unit further includes a first pilot oil path d1 and a second pilot oil path d2, wherein, the first pilot oil path d1 is configured to control the operation of the sequence valve k2 to switch the control unit between the initial state and the loaded state, and the second pilot oil path d2 is configured to control the operation of the pressure reducing valve k1 to control the input flow rate from the port P. By such a setting, the present application can achieve on-demand opening, wherein pressure reduction and overflow are carried out first and then sequential opening is carried out, in this way, even if the manufacture precision of the pressure reducing valve k1 and the sequence valve k2 is relatively low and causes a relatively large gap to exist between a valve spool of the pressure reducing valve k1 and a housing of the pressure reducing valve k1 and a relatively large gap to exist between a valve spool of the sequence valve k2 and a housing of the sequence valve k2, it still can be ensured that a braker 6 connected with the port B works normally, thereby completely solving the adverse influence of jittering brought by the overflow unloading, and effectively preventing winch jittering in a winch micro-action working condition in the winch system. In the present application, in the initial state, an outlet of the unloading damper k3 is in communication with both the port B and the port T simultaneously, so that the port B is also in communication with the port T, and while pressure at the port P gradually decreases and the sequence valve k2 is being reset from the loaded state to the initial state, since the port B is kept in communication with the port T, it can achieve rapid pressure relief at a control port and prevent action delay.

[0021] In an embodiment shown in Fig. 1, the sequence valve k2 has two work-positions, when the first work-position k21 of the sequence valve k2 is connected, the port B becomes in communication with the outlet of the pressure reducing valve k1 from the inlet side of the unloading damper k3, and when the second work-position k22 of the sequence valve k2 is connected, pressure oil conveyed from the port P is delivered to the port T and the port B simultaneously via the unloading damper k3.

[0022] In another embodiment, two ends of the first pilot oil path d1 are connected to a control end of the sequence valve k2 and the inlet of the unloading damper k3 respectively, and according to pressure at the inlet side of the unloading damper k3, the sequence valve k2 drives the valve spool of the sequence valve k2 to move to achieve switching between the initial state and the loaded state, wherein, pressure at the inlet of the unloading damper k3 is consistent with pressure at the outlet of pressure reducing valve k1.

[0023] In another embodiment, two ends of the second pilot oil path d2 are connected to a control end of the pressure reducing valve k1 and the inlet of the unloading damper k3 respectively, and since inlet pressure of the unloading damper k3 is consistent with outlet pressure of the pressure reducing valve k1, that is to say, in the present application, the inlet flow rate at the port P is adjustable via the second pilot oil path d2 according to the outlet pressure of the pressure reducing valve k1, thus, the port P can provide as much pressure as the port B needs.

[0024] Wherein, the pressure reducing valve k1 and / or the sequence valve k2 are provided with an oil drain hole, which is in communication with the port T. As show in Fig. 1, the oil drain hole of the pressure reducing valve k1 is in direct communication with the port T via a fourth oil path L4 and returns to the oil tank. The oil drain hole of the sequence valve k2 is in direct communication with the port T via a fifth oil path L5 and returns to the oil tank.

[0025] In the present application, the pressure reducing valve k1, the sequence valve k2 and the unloading damper k3 may be configured as multiple independent valves, and then are connected by external pipelines, or it may also be configured that at least two of them sharing a common housing to form a valve group.

[0026] For example, a housing of the pressure reducing valve k1 and a housing of the sequence valve k2 form an integral valve body 1, with the port P, the port T, and the port B formed on the valve body 1. Certainly, the valve body 1 may also be a common housing for all the three.

[0027] Referring to one embodiment as shown in Fig. 2, the pressure reducing valve k1, the sequence valve k2 and the unloading damper k3 share a same valve body 1 as a housing, a valve spool of the pressure reducing valve k1 and a valve spool of the sequence valve k2 form an integral main valve spool 2, with the unloading damper k3 formed on the main valve spool 2, the valve body 1 has a valve chamber 10, the main valve spool 2 is slidably arranged in the valve chamber 10, the port P, the port T and the port B penetrate a wall of the valve body 1 and are in communication with the valve chamber 10.

[0028] Wherein, the main valve spool 2 is provided with a central oil passage 2a extending along an axial direction, the unloading damper k3 includes a damping hole 2b penetrating the wall of the main valve spool 2 to be in communication with the central oil passage 2a, and the main valve spool 2 is further provided with a pressure oil port 2c penetrating the wall of the main valve spool 2 to be in communication with the central oil passage 2a; in the initial state, the port P is in communication with the port T and the port B simultaneously through the pressure oil port 2c, the central oil passage 2a, and then the damping hole 2b. Wherein, in order to make the main valve spool 2 be reset automatically after the pressure at the port P decreases, a pressure spring 3 is arranged on one end of the maim valve spool 2. By such a setting, in the initial state, the port P is in communication with both the port B and the port T via the damping hole 2b to carry out pressure reduction and overflow first, and when the pressure acting on the main valve spool 2 in the axial direction is greater than the opening threshold force of the pressure spring 3, the main valve spool 2 is gradually moved toward the pressure spring 3 until the damping hole 2b is disconnected from the port B, and the port B becomes directly in communication with the port P to achieve sequential opening, wherein, the pressure supplied from the port P is adapted to the pressure required for the main valve spool 2 to open. After the main valve spool 2 has been moved to an extreme position where it cannot be moved further toward the direction of the pressure spring 3, the port P can then be disconnected from the pressure oil port 2c.

[0029] The arrangement of the pressure spring 3 is as shown in Fig.2, a valve seat 5 is arranged in the valve chamber 10, and the above-mentioned pressure spring 3 is also mounted in the valve chamber 10, one end of the pressure spring 3 is mounted on the valve seat 5, and the other end thereof abuts against the main valve spool 2, referring to the Fig. 3 as shown, the main valve spool 2 has a mounting rod 26, and the outer diameter of the mounting rod 26 is smaller than the inner diameter of the pressure spring 3, the mounting rod 26 is inserted in the center hole of the pressure spring 3.

[0030] In the present application, the main valve spool 2 is cylindrical in shape, and the outer periphery of the main valve core 2 is provided with a plurality of annular grooves and a shoulder located between every two adjacent annular grooves. The annular grooves are utilized to enable oil liquid to be distributed 360° around the circumference of the main valve spool 2, therefore, when controlling each oil path, it only needs to control the main valve spool 2 to move axially within the valve chamber 10.

[0031] In an embodiment as shown in Fig. 2 and Fig. 3, the central oil passage 2a is a blind hole, and an opening of the central oil passage 2a is located at an end face of one end of the main valve spool 2 far away from the pressure spring 3.

[0032] In another embodiment, in the initial state, a gap exists between the valve body 1 and the end face of one end of the main valve spool 2 far away from the pressure spring 3, so that pressure oil that has been leaked into a space between the main valve spool 2 and the valve body 1 flows from the opening of the central oil passage 2a into the central oil passage 2a, and then is able to return to the oil tank.

[0033] In another embodiment, a valve sleeve 11 has a first annular groove c1 that is open on an inner surface of the valve sleeve 11, referring to Fig. 2 as shown, an inner end of the port B is open on a bottom wall of the first annular groove c1, referring to Fig. 2 and Fig. 3 as shown, a second annular groove c2 and a third annular groove c3 are formed on the main valve spool 2, and the second annular groove c2 and the third annular groove c3 are open on the outside surface of the main valve spool 2, a third shoulder 23 is formed between the second annular groove c2 and the third annular groove c3. Wherein, the second annular groove c2 is located at a side of the third shoulder 23 adjacent to the pressure spring 3, an outer end of the damping hole 2b is open on a bottom wall of the second annular groove c2, the main valve spool 2 is also provided with a fourth annular groove c4, which is open on the outside surface of the main valve spool 2, a groove channel 24a extending in the axial direction is provided in a fourth shoulder 24 between the fourth annular groove c4 and the second annular groove c2, the damping hole 2b is in communication with the port T via the groove channel 24a. By setting the groove channel 24a, a certain back pressure can be provided when returning oil to the port T.

[0034] In an embodiment as shown in the Fig. 2, in any status, the damping hole 2b is always in communication with the fourth annular groove c4 via the groove channel 24a, and thus is always in communication with the port T.

[0035] In an embodiment as shown in the Fig. 2, in the initial state, the second annular groove c2 is in communication with the first annular groove c1, the damping hole 2b allows the port B to be in communication with the central oil passenger 2a via the second annular groove c2 and the first annular groove c1, and thus be in communication with the port P via the pressure oil port 2c. That is to say, at this time, the port P is in communication with the central oil passenger 2a via the pressure oil port 2c, and then is in communication with both the port B and the port T simultaneously via the damping hole 2b, thereby achieving the function of pressure reduction and overflow of the present application.

[0036] In another embodiment, the main valve spool 2 is provided with a pilot oil hole 2d penetrating the wall of the main valve spool 2 to be in communication with the central oil passage 2a, in the loaded state, the damping hole 2b is disconnected from the port B, and the port P is in communication with the port B, wherein, the pressure oil conveyed from the port P via the pressure oil port 2c flows along the central oil passage 2a to the pilot oil hole 2d, which forms the first pilot oil path d1 shown in Fig. 1, the main valve spool 2 can be moved under the action of the first pilot oil path d1, so that the pilot oil hole 2d becomes in communication with the port B, thereby switching the control unit from the initial state to the loaded state. Referring to Figure 2 as shown, a first inner shoulder 11b is formed on a side of the first annular groove c1 near the pressure spring 3, in the initial state, the first inner shoulder 11b is axially located in the middle of the second annular groove c2, so that the damping hole 2b can be in communication with the port B via the second annular groove c2 and the first annular groove c1, and at the same time, the damping hole 2b is in communication with the port T via the groove channel 24a and then via the fourth annular groove c4, thereby achieving pressure reduction and overflow. When switching from the initial state to the loaded state, as pressure at the port P increases, pressure in the central oil passage 2a also increases gradually, and under the action of the axial force, the main valve spool 2 is pushed to move toward a direction of the pressure spring 3, and the third shoulder 23 approaches the first inner shoulder 11b gradually until it abuts against the first inner shoulder 11b, so that the damping hole 2b is disconnected from the first annular groove c1, and at this time, the pilot oil hole 2d becomes in communication with the third annular groove c3 via a fifth annular groove c5. Wherein, the fifth annular groove c5 is open on the outer surface of the main valve spool 2, and an outer end of the pilot oil hole 2d is open on a bottom wall of the fifth annular groove c5. A second inner shoulder 11d is formed on another side of the first annular groove c1 near the pressure oil port 2c, in the initial state, the second inner shoulder 11d abuts against a first shoulder 21, so that the port B cannot be in communication with the port P via the fifth annular groove c5, the pilot oil hole 2d and the central oil passenger 2a. When switching from the initial state to the loaded state, the first shoulder 21 is moved toward the pressure spring 3 relative to the second inner shoulder 11d, and the second inner shoulder 11d and the first shoulder 21 become out of contact gradually, so that the fifth annular groove c5 becomes in communication with the first annular groove c1, and thus the port P is able to become in communication with the port B via the pressure oil port 2c and the central oil passenger 2a, from the pilot oil hole 2d via the fifth annular groove c5, and then via the first annular groove c1, which forms the first oil path L1 as shown in Fig. 1 and Fig. 4, and at the same time, the third shoulder 23 becomes abutting against the first inner shoulder 11b, so as to disconnect the damping hole 2b from the port B. And thus, the port P and the port B become in direct communication with each other from an inlet side of the damping hole 2b. At this time, the damping hole 2b becomes only in communication with the port T, which can prevent mutual interference due to the pressure shock caused by a situation wherein the pressure oil on one hand converges toward the port B from a side of the port B near the pressure spring 3, and on the other hand, converges toward the port B from another side of the port B far away from the pressure spring 3.

[0037] In the present application, when the main valve spool 2 is in the loaded state, after the port P and the port B become indirect communication with each other via the pilot oil hole 2d, if oil pressure continues to rise, under the action of the pressure oil in the central oil passage 2a, that is, under the action of the second pilot oil path d2, a control edge LX of a sixth annular groove c6 is moved relative to a port edge LT of the port P to form a throttle orifice, which can adjust the flow rate at the port P, and thus the system can provide as much pressure as the Port B requires.

[0038] When the pressure at the port P decreases gradually, under the action of reset force of the pressure spring 3, the main valve spool 2 is moved toward the pressure oil port 2c, and the first inner shoulder 11b and the third shoulder 23 become out of contact gradually from the status of abutting against each other, so that the port B becomes in communication with the port T to achieve the rapid pressure relief in the central oil passage 2a and to prevent any delay in valve action.

[0039] In another embodiment, a fifth shoulder 25 is formed between the fourth annular groove c4 and the mounting rod 26, and an outer wall of the fifth shoulder 25 abuts against an inner wall of the valve chamber 10. The fifth shoulder 25 is provided with an oil drain hole 25a axially penetrating the fifth shoulder 25, and the oil drain hole 25a is in communication with the port T via the fourth annular groove c4 to achieve oil drainage.

[0040] In another embodiment, the valve body 1 includes the valve sleeve 11 and a valve base 12, one of the valve sleeve 11 and the valve base 12 has an internal thread, and the other of them has an external thread, the internal and external threads of the two are connected together.

[0041] Further, one of the valve sleeve 11 and the valve base 12 that is located on the outside is also provided with another external thread for installing the control unit of the present application onto a mechanism that uses the control unit. In an embodiment as shown in Fig. 2, the valve sleeve 11 has an external thread, and the valve base 12 has an internal thread which matches with the external thread of the valve sleeve 11. Meanwhile, the valve base 12 also has another external thread for fixing the control unit onto another mechanism.

[0042] Further, the control unit includes a sealing ring 4 sleeved on an exterior of the control unit of the present application to ensure the sealing between the control unit and the above-mentioned mechanism. In an embodiment as shown in Fig. 2, the sealing ring 4 is sleeved on the outer peripheral of the valve base 12.

[0043] In the second aspect, the present application provides a hydraulic system, which includes the above-mentioned control unit and an execution unit, wherein, the port B is in communication with the execution unit. The hydraulic system has the same technical advantages that the above-mentioned control unit possesses, which will not be repeated herein.

[0044] In another embodiment, the execution unit includes a motor 7 and a braker 6 used for braking the motor 7, the port B is in communication with a brake cylinder of the braker 6, the hydraulic system further includes a first pipeline g1 and a second pipeline g2, and the motor 7 has two oil ports, one of the two oil ports is connected to a second main pressure port oil B' through the first pipeline g1, and the other of the two oil ports is connected to a first main pressure oil port A' through the second pipeline g2, the port P is in communication with one of the first pipeline g1 and the second pipeline g2 that has a higher pressure. In the initial state, this hydraulic system pre-fills part of the pressure oil to the braker 6 via the port B.

[0045] Further, the port P is in communication with one of the first main pressure oil port A' and the second main pressure oil port B' that has a higher pressure through a shuttle valve.

[0046] In another embodiment, the hydraulic system further includes a balance valve k5, the balance valve k5 is mounted on one of the first pipeline g1 and the second pipeline g2, and a control end of the balance valve k5 is connected to the other of the first pipeline g1 and the second pipeline g2.

[0047] Referring to an embodiment as shown in Fig. 4, pressure oil flows from the second main pressure oil port B' along the first pipeline g1 into the motor 7, part of the pressure oil overcomes the spring pressure of the balance valve k5 to push the valve stem of the balance valve k5 to open the balance valve k5, so that a second work position k52 of the balance valve k5 is connected, and the second pipeline g2 becomes in communication with the motor 7 and the first main pressure port A'. Wherein, a throttle valve is arranged in the second work position k52 of the balance valve k5 to provide back pressure for the motor 7.

[0048] When pressure oil flows from the first main pressure oil port A' along the second pipeline g2 into the motor 7, wherein, a check valve is arranged in the first work position k51, under the action of the check valve, the first work position k51 of the balance valve k5 is connected, so that the motor 7 is in communication with the first main pressure oil port A'.

[0049] Regardless of whether pressure oil is input into the motor 7 from the first main pressure oil port A' or the second main pressure oil port B', the port P of the control unit of the present application is always in communication with the one of the first main pressure oil port A' and the second main pressure oil port B' that has a higher pressure, and the port B is in communication with the braker 6. Overflow and pressure reduction are carried out first, and then the sequence valve k2 is sequentially opened to apply pressure to the braker 6. In this way, it is ensured that the braker 6 operates normally.

[0050] Wherein, when the motor 7 is used for driving a winch mechanism, at this time, the hydraulic system of the present application can effectively solve the problem of winch jittering in a micro-action working condition.

[0051] The lifting and lowering operations of a winch will be described below to explain the present application even further.

[0052] When the winch performs lifting, main pressure oil flows from the first main pressure oil port A' along the second pipeline g2 into the motor 7, and the motor 7 rotates in a forward direction, part of the pressure oil conveyed from the first main pressure oil port A' flows into the control unit of the present application via the shuttle valve k4 and then via the port P, and as the first work position k21 of the sequence valve k2 is connected, pressure oil is conveyed to the braker 6 via the port B, the braker 6 is opened, while the motor 7 rotates in a forward direction, and the winch performs lifting.

[0053] When the winch performs lowering, main pressure oil flows from the second main pressure port oil B' along the first pipeline g1 into the motor 7, part of the pressure oil overcomes spring pressure of the balance valve k5 to push the valve stem of the balance valve k5 to open the balance valve k5, so that the outlet of the motor 7 is in communication with the first main pressure oil port A' via the second pipeline g2.

[0054] Another part of the pressure oil enters the control unit of the present application via the shuttle valve k4, and then is depressurized by the pressure reducing valve k1, part of the depressurized pressure oil overflows via the unloading damper k3, part of the overflowing pressure oil returns to the oil tank, and the other part thereof is in communication with the braker 6 via the sequence valve k2, so as to pre-fill part of the pressure oil into a brake pipeline.

[0055] At the same time, the other part of the depressurized pressure oil directly acts on a control end of the sequence valve k2 via the first pilot oil path d1, referring to Fig. 1 and Fig. 4, when the pressure reaches the opening pressure of the sequence valve k2, the sequence valve k2 is opened, and the first work position k21 of the sequence valve k2 is connected so as to directly convey the pressure oil to the braker 6 via the port B, and then the braker is opened.

[0056] The motor 7 returns oil to the first main pressure oil port A' via the second pipeline g2, and the motor rotates in a backward direction to achieve the lowering operation of the winch.

[0057] The third aspect of the present application provides an operation machine, which includes the above-mentioned hydraulic system. The operation machine has the same technical advantages that the hydraulic system possesses, which will not be repeated herein.

[0058] The operation machine further includes a pump, the pump especially has two ports, one of two ports is an inlet, and the other thereof is an outlet, the inlet and the outlet of the pump are in communication with the two oil ports of the motor 7 via the first main pressure oil port A' and the second main pressure oil port B' respectively.

[0059] It can be understood that the term "and / or" in the present document is only an association relationship describing associated objects, and represents that three relationships can exist. For example, A and / or B can represent three situations: the existence of A alone, the coexistence of A and B, and the existence of B alone, wherein both A and B can be singular or plural. In addition, the character " / " in the present document generally represents an "or" relationship between the preceding and succeeding associated objects, but probably may also represent an "and / or" relationship, which can be understood specifically by referring to the context.

[0060] In the present application, "a plurality of" represents two or more. "at least a (one) of the following items" or other similar expressions refer to any combination of these items, which includes any combination of single item (one) or plural items (ones). For example, at least one of a, b, and c represents a, b, c, a-b, a-c, b-c or a-b-c, in which a, b and c can be singular or plural.

[0061] It can be understood that in various embodiments of the present application, the magnitude of the serial numbers of each of the above-mentioned process steps does not mean the order of execution. The execution order of each process step should be determined based on its function and internal logic, and such serial numbers should not constitute any limitation on the implementation process of the embodiments of the present application.

[0062] The above descriptions are merely preferable embodiments of the present application, and are not intended to limit the present application, and any modifications, equivalent substitutions, etc. made to these embodiments within the spirit and principles of the present application shall be included within the protection scope of the present application.

Claims

1. A control unit, having a port P in communication with a pressure source, a port T in communication with an oil tank and a port B in communication with an execution unit, wherein, the control unit comprises a pressure reducing valve (k1), a sequence valve (k2) and an unloading damper (k3) connected between the port P and the port B, and the control unit is configured so that: in an initial state, pressure oil conveyed from the port P is delivered to the port T and the port B simultaneously via the unloading damper (k3); in a loaded state, pressure oil conveyed from the port P can be delivered to the port B from an inlet side of the unloading damper (k3), and the port B is disconnected from the unloading damper (k3); the control unit further comprises a first pilot oil path (d1) and a second pilot oil path (d2), wherein, the first pilot oil path (d1) is configured to control the operation of the sequence valve (k2) to switch the control unit between the initial state and the loaded state, and the second pilot oil path (d2) is configured to control the operation of pressure reducing valve (k1) to control the input flow rate from the port P.

2. The control unit according to claim 1, wherein, two ends of the first pilot oil path (d1) are connected to a control end of the sequence valve (k2) and an inlet of the unloading damper (k3) respectively, and / or, two ends of the second pilot oil path (d2) are connected to a control end of the pressure reducing valve (k1) and the inlet of the unloading damper (k3) respectively.

3. The control unit according to claim 1 or 2, wherein, a housing of the pressure reducing valve (k1) and a housing of the sequence valve (k2) form an integral valve body (1), with the port P, the port T, and the port B formed on the valve body (1).

4. The control unit according to claim 3, wherein, a valve spool of the pressure reducing valve (k1) and a valve spool of the sequence valve (k2) form an integral main valve spool (2), with the unloading damper (k3) formed on the main valve spool (2), the valve body (1) has a valve chamber (10), the main valve spool (2) is slidably arranged in the valve chamber (10), the port P, the port T and the port B penetrate a wall of the valve body (1) and are in communication with the valve chamber (10).

5. The control unit according to claim 4, wherein, the main valve spool (2) is provided with a central oil passage (2a) extending along an axial direction, the unloading damper (k3) comprises a damping hole (2b) penetrating the wall of the main valve spool (2) to be in communication with the central oil passage (2a), the main valve spool (2) is further provided with a pressure oil port (2c) penetrating the wall of the main valve spool (2) to be in communication with the central oil passage (2a): in the initial state, the port P is in communication with both the port T and the port B simultaneously through the pressure oil port (2c), the central oil passage (2a), and then the damping hole (2b).

6. The control unit according to claim 5, wherein, the main valve spool (2) is provided with a pilot oil hole (2d) penetrating the wall of the main valve spool (2) to be in communication with the central oil passage (2a), in the loaded state, the damping hole (2b) is disconnected from the port B, the port P is in communication with the port B, wherein, the pressure oil conveyed from the port P via the pressure oil port (2c) flows along the central oil passage (2a) to the pilot oil hole (2d), which forms the first pilot oil path (d1), the main valve spool (2) can be moved under the action of the first pilot oil path (d1), so that the pilot oil hole (2d) becomes in communication with the port B, thereby switching the control unit from the initial state to the loaded state.

7. A hydraulic system, wherein, the hydraulic system comprises the control unit according to any one of claims 1 to 6 and an execution unit, the port B is in communication with the execution unit.

8. The hydraulic system according to claim 7, wherein, the execution unit comprises a motor (7) and a braker (6) for braking the motor (7), the port B is in communication with a brake cylinder of the braker 6, the hydraulic system further comprises a first pipeline (g1) and a second pipeline (g2), the motor (7) has two oil ports, one of the two oil ports is connected to a first main pressure oil port (A') through the first pipeline (g1), and the other of the two oil ports is connected to a second main pressure oil port (B') through the second pipeline (g2), the port P is in communication with one of the first pipeline (g1) and the second pipeline (g2) that has a higher pressure.

9. The hydraulic system according to claim 8, wherein, the hydraulic system further comprises a balance valve (k5), the balance valve (k5) is mounted on one of the first pipeline (g1) and the second pipeline (g2), and a control end of the balance valve (k5) is connected to the other of the first pipeline (g1) and the second pipeline (g2).

10. An operation machine, wherein, the operation machine comprises the hydraulic system according to any one of claims 1 to 9.

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