A five-hole servo reversing valve with differential function

Abstract

The present invention relates to the technical field of reversing valves, and discloses a five-hole servo reversing valve with a differential function, comprising: a main valve body, wherein the main valve body adopts a three-shoulder and five-sunk groove structure; the main valve body is provided with an oil chamber and an oil port; the oil chambers are respectively a first working chamber, a second working chamber, a third working chamber, an oil inlet chamber and an oil return chamber; the oil ports are respectively a third output port opened on the third working chamber; the third working chamber and the third output port are used to realize a differential function; the reversing valve can effectively solve the problem of insufficient liquid replenishment in the rodless chamber of a large-flow servo valve in the prior art during differential locking, through the third working chamber, ensure that the regenerated liquid is effectively utilized, avoid the waste of hydraulic energy, and reduce the energy loss caused by the direct return of the regenerated liquid to the oil tank; the lateral arrangement of the electrical interface simplifies the system integration work, reduces the risk of trampling damage during installation, and reduces the hardware cost and the difficulty of later maintenance.

Description

Technical Field

[0001] The invention relates to the technical field of reversing valves, and in particular to a five-hole servo reversing valve with a differential function. Background Art

[0002] In the vast system of modern plastic products industry, PET preform injection molding machines play a pivotal role. Their main task is to manufacture polyethylene terephthalate (PET) preforms in a large-scale and efficient manner. As intermediate products, these preforms will be transformed into consumer packaging containers of various shapes and specifications after subsequent blow molding, such as PET beverage bottles, edible oil bottles, and cosmetic bottles that are common in people's daily lives. In response to this industry demand, large-scale PET preform injection molding machines have widely adopted large-flow servo valve technology to ensure the rapid and smooth opening and closing of the mold, as well as the precise execution of key operations such as low-pressure mold protection.

[0003] However, this type of servo valve has the following significant problems:

[0004] During the differential clamping process of a large PET preform injection molding machine, the large-flow servo valve cannot effectively replenish the rodless chamber of the oil inlet cylinder, resulting in the regeneration liquid that should have been used for pressurization not being effectively utilized, but directly flowing back to the oil tank, causing a waste of hydraulic energy. In addition, because the kinetic energy of the regeneration liquid cannot be converted into effective clamping force, and the frequent backflow increases the heat accumulation of the oil inside the oil tank, it may aggravate the heat load of the hydraulic system; this is obviously not conducive to improving the overall efficiency of the system.

[0005] To solve this problem, manufacturers will add an external valve body to the servo valve to convert its function, thereby recovering and reusing this part of the regenerated liquid. In theory, such an improvement can avoid waste of resources and improve the energy utilization rate of the hydraulic system. However, in practical applications, this solution has brought new problems; the addition of a valve body makes the system structure more complicated, which not only increases the hardware cost, but also increases the difficulty of installation, commissioning and subsequent maintenance. More importantly, it is difficult for the two sets of valves (the original servo valve and the additional valve body) to achieve ideal precise synchronization between switching and response, which easily leads to oil grabbing, that is, the two valves interfere with each other when competing for the hydraulic source, resulting in turbulent flow of hydraulic oil.

[0006] First, the turbulent state of hydraulic oil directly affects the stability of the mold clamping process, which may cause the mold clamping action to be fast or slow, or violent impact, seriously threatening the safety of the equipment, accelerating the wear of key components such as hydraulic cylinders, seals and molds, and shortening the service life of the equipment. Secondly, due to the unstable mold clamping caused by oil grabbing, low-pressure mold protection control becomes more difficult, because the system needs to accurately judge and maintain the appropriate clamping pressure in a complex hydraulic fluctuation environment, which undoubtedly increases the calculation burden and response difficulty of the control system. Finally, due to the high frequency of oil grabbing, PET preform injection molding machines often encounter mold damage caused by hydraulic shock, which causes premature damage to the PET preform mold, increasing mold maintenance costs and production interruption risks.

[0007] In summary, it is found that the prior art has at least the following technical problems:

[0008] The existing PET preform injection molding machines, due to the use of large-flow servo valves, have the problems of being unable to perform rodless cavity refilling, insufficient utilization of regenerated liquid, poor synchronization and low stability between valves, and difficulty in controlling low-pressure mold protection. Summary of the invention

[0009] In view of this, an object of the present invention is to provide a five-hole servo reversing valve with a differential function to solve the problems existing in the above-mentioned background technology.

[0010] In order to solve the above technical problems, the technical solution of the present invention is a five-hole servo reversing valve with a differential function, characterized in that it includes: a main valve body, the main valve body adopts a three-shoulder five-sink cut groove structure; the main valve body is provided with an oil chamber and an oil port; the oil chambers are respectively a first working chamber, a second working chamber, a third working chamber, an oil inlet chamber and an oil return chamber; the oil ports are respectively a first output port opened on the first working chamber, a second output port opened on the second working chamber, a third output port opened on the third working chamber, a first oil inlet port opened on the oil inlet chamber and a first oil return port opened on the oil return chamber; the third working chamber and the third output port are used to realize the differential function; a main valve core; the main valve core is located in the oil chamber; a pilot valve; the pilot valve is arranged on the main valve body, and a pilot oil circuit is formed between the pilot valve and the main valve body to drive the main valve core to reciprocate in the main valve body, so that the oil in the first oil inlet is connected to different oil ports respectively, so as to realize the reciprocating and differential reciprocating of the oil cylinder, and realize the opening and closing of the mold and the rapid mold shifting action.

[0011] Preferably, the pilot oil circuit includes a pilot oil inlet and a pilot oil return port opened on the main valve body, and the pilot valve has a second oil inlet and a second oil return port; the pilot oil inlet is connected to the second oil inlet, and the pilot oil return port is connected to the second oil return port; the pilot valve uses the pilot oil inlet to allow a small amount of oil to enter the main valve body to promote the movement of the main valve core, and the oil then returns to the oil tank through the pilot oil return hole; a large range and precise control of the main valve core can be achieved with a small amount of oil.

[0012] Preferably, the pilot valve has a first connecting port and a second connecting port; the pilot valve includes a pilot valve body and a pilot valve core; electromagnetic control units are provided at both ends of the pilot valve body to control the oil to flow out from the first connecting port or the second connecting port after passing through the second oil inlet; a first spring chamber and a second spring chamber are respectively provided on both sides of the main valve body, the first spring chamber has a first control channel, and the second spring chamber has a second control channel; the first connecting port is connected to the first control channel, and the second connecting port is connected to the second control channel; the first control channel and the second control channel realize a wide range and precise control of the main valve core.

[0013] Preferably, the pilot valve further comprises an electrical interface, and the electrical interface is arranged laterally on the pilot valve; the lateral access of the electrical interface can simplify system integration and avoid trampling damage.

[0014] Preferably, a safety valve is further provided between the main valve body and the pilot valve to control the oil conduction of the pilot oil circuit between the pilot valve and the main valve body.

[0015] Furthermore, the safety valve is a plunger slide valve, and a pre-load spring is additionally provided in the structure of the plunger slide valve; when the pressure of the pilot oil circuit changes, the displacement on both sides of the plunger slide valve is utilized to realize stable control of the pilot pressure; even if a power outage occurs, the plunger slide valve, under the action of the pre-load spring, keeps the valve core of the plunger slide valve in the middle position.

[0016] Preferably, the second output port is connected to the rod chamber of the downstream component, and the first output port and the third output port merge to merge the high-pressure liquid and connect to the rodless chamber of the downstream component to achieve consistency in flow between the rodless chamber and the rod chamber.

[0017] Preferably, the positive cover of the first oil inlet is 20%, and the negative cover of the first oil return port is 15%; the oil of the first oil inlet flows to the first output port and the second output port; the oil of the second output port flows to the first oil return port and the third output port; the oil of the first output port flows to the first oil return port.

[0018] Furthermore, the ratio of the oil from the first oil inlet to the first output port and the second output port is 1:2; the flow rate of the oil from the first output port to the first oil return port is A, and the flow rate of the oil from the first oil inlet to the first output port is B, A:B=1:2.

[0019] The technical effects of the present invention are mainly reflected in the following aspects: the reversing valve can effectively solve the problem of insufficient liquid replenishment of the rodless cavity in the differential mold locking process of the large flow servo valve in the prior art through the third working chamber, ensure the effective utilization of the regenerated liquid, avoid the waste of hydraulic energy, and reduce the energy loss caused by the direct return of the regenerated liquid to the oil tank. The setting of the pilot valve allows the reversing valve to achieve precise control of the main valve core through a small amount of oil, which not only improves the control accuracy, but also improves the stability of the entire hydraulic system. This helps to eliminate the turbulence of the hydraulic oil flow and prevent the oil grabbing phenomenon, thereby ensuring the stability of the mold closing process, reducing the risk of mold collision, and extending the service life of the equipment. Through the design of the electromagnetic control unit and the spring chamber on both sides of the main valve body, a large range and precise control of the main valve core is achieved, the synchronization between the valves is enhanced, and the synchronous response in the opening and closing and rapid mold shifting actions is ensured, solving the problem of uncoordinated switching and response of the two sets of valve bodies in the traditional solution. The lateral arrangement of the electrical interface simplifies the system integration work, reduces the risk of trampling damage during installation, and reduces the hardware cost and difficulty of later maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural diagram of a five-hole servo reversing valve with a differential function according to the present invention;

[0021] Figure 2 A bottom view of a five-hole servo reversing valve with a differential function according to the present invention;

[0022] Figure 3 It is a partial cross-sectional view of a five-hole servo reversing valve with a differential function according to the present invention;

[0023] Figure 4 This is a schematic diagram of the oil circuit of a five-hole servo reversing valve with a differential function according to the present invention;

[0024] Figure 5 This is a flow curve diagram of a five-hole servo reversing valve with a differential function according to the present invention;

[0025] In the figure: 1. main valve body, 11. first working chamber, 12. second working chamber, 13. third working chamber, 14. oil inlet chamber, 15. oil return chamber; 21. first output port, 22. second output port, 23. third output port, 24. first oil inlet port, 25. first oil return port, 26. pilot oil inlet port, 27. pilot oil return port; 3. main valve core; 31. first spring chamber, 32. second spring chamber, 33. first control channel, 34. second control channel; 4. pilot valve, 41. second oil inlet port, 42. second oil return port, 43. first connecting port, 44. second connecting port, 5. safety valve. DETAILED DESCRIPTION

[0026] The specific implementation modes of the present invention are further described below in conjunction with the accompanying drawings to make the technical solutions of the present invention easier to understand and grasp.

[0027] In this embodiment, it should be understood that the terms "middle", "upper", "lower", "top", "right", "left end", "above", "back", "middle", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0028] In addition, in this specific embodiment, if the connection or fixing method between components is not specifically described, the connection or fixing method can be through bolt fixing or pin fixing, or pin shaft connection and the like commonly used in the prior art, and therefore, it will not be described in detail in this embodiment.

[0029] Embodiment 1

[0030] See also Figure 1 , 4A five-hole servo reversing valve with differential function includes a main valve body 1, wherein the main valve body 1 adopts a three-shoulder five-sink cut groove structure; the main valve body 1 has an oil chamber and an oil port; the configuration of the oil chamber and the oil port ensures the precise control and flow distribution of the oil. The oil chambers are respectively a first working chamber 11, a second working chamber 12, a third working chamber 13, an oil inlet chamber 14 and an oil return chamber 15; the oil ports are respectively a first output port 21 opened on the first working chamber 11, a second output port 22 opened on the second working chamber 12, a third output port 23 opened on the third working chamber 13, a first oil inlet port 24 opened on the oil inlet chamber 14 and a first oil return port 25 opened on the oil return chamber 15; the third working chamber 13 and the third output port 23 are used to realize the differential function; and the efficient operation of mold opening and closing and rapid mold shifting is realized. The differential function is mainly in the hydraulic system, by quickly injecting different amounts of hydraulic oil into the rodless chamber and the rod chamber to realize a rapid and powerful mold opening and closing action. In the embodiment, the third working chamber 13 is used as a special hydraulic chamber, connected to the third output port 23, and is specifically used for oil distribution during differential operation. It can effectively solve the problem of insufficient liquid replenishment in the rodless chamber of the large flow servo valve in the differential clamping process in the prior art, ensure the effective use of the regenerated liquid, avoid the waste of hydraulic energy, and reduce the energy loss caused by the direct return of the regenerated liquid to the oil tank.

[0031] The second output port 22 is connected to the rod chamber of the downstream component, and the first output port 21 and the third output port 23 converge, merge the high-pressure liquid and connect the rodless chamber of the downstream component, so as to achieve the consistency of the flow of the rodless chamber and the rod chamber, significantly improve the stability of the mold closing process, reduce the risk of mold damage, and thus extend the service life of the equipment and reduce the maintenance cost. In the upper and lower chambers of the hydraulic cylinder (rodless chamber and rod chamber), the flow of hydraulic oil flowing into the two chambers is kept consistent or controlled at a specific ratio through the above-mentioned flow convergence control. The rodless chamber usually refers to the chamber on the side where the piston rod does not extend, and the rod chamber is the chamber on the side where the piston rod passes. Under the control of the pilot valve 4, the oil of the first oil inlet 24 undergoes precise flow distribution, and a part of the oil flows to the first output port 21 and the second output port 22 for conventional reciprocating motion of the oil cylinder; at this time, the oil of the second working chamber 12 flows from the third output port 23 to the third working chamber 13 through the second output port 22. In the differential operation mode, the oil in the third working chamber 13 is rapidly supplied to the rodless chamber of the oil cylinder through the third output port 23, so that the oil pressure in the rodless chamber rises rapidly. While achieving rapid movement, the oil reflux in the rod chamber through the first and second output ports 22 is balanced, ensuring the differential effect, that is, while the mold is opened and closed quickly, the movement speed and torque on both sides of the mold are precisely controlled.

[0032] See also Figure 2 , 3, main valve core 3; the main valve core 3 is located in the oil chamber; pilot valve 4; the pilot valve 4 is arranged on the main valve body 1, and a pilot oil circuit is formed between the pilot valve 4 and the main valve body 1 to drive the main valve core 3 to move back and forth in the main valve body 1, so that the oil in the first oil inlet 24 is connected to different oil ports respectively, so as to realize the reciprocating and differential reciprocating of the oil cylinder, and realize the opening and closing of the mold and the rapid mold shifting. Through the pilot oil circuit system formed between the pilot valve 4 and the main valve body 1, the main valve core 3 can be driven to realize a wide range of precise movement with the help of precise control of a small amount of oil.

[0033] The main valve body has three working positions, namely, a middle position, a left position and a right position. The second working chamber 12 and the third working chamber 13 in the main valve body are switched between connection and closure through the movement of the main valve core 3 .

[0034] The pilot oil circuit includes a pilot oil inlet 26 and a pilot oil return port 27 provided on the main valve body 1, and the pilot valve 4 has a second oil inlet 41 and a second oil return port 42; the pilot oil inlet 26 is connected to the second oil inlet 41, and the pilot oil return port 27 is connected to the second oil return port 42; the pilot valve 4 utilizes the pilot oil inlet 26 to allow a small amount of oil to enter the main valve body 1 to push the main valve core 3 to move, and the oil then returns to the oil tank through the pilot oil return hole; a large range and precise control of the main valve core 3 can be achieved with a small amount of oil.

[0035] The pilot valve 4 is provided with a first connection port 43 and a second connection port 44; the pilot valve 4 comprises a pilot valve body 4 and a pilot valve core 4; both ends of the pilot valve body 4 are provided with an electromagnetic control unit to control the oil to flow out from the first connection port 43 or the second connection port 44 after passing through the second oil inlet 41; the main valve body 1 is provided with a first spring chamber 31 and a second spring chamber 32 on both sides, the first spring chamber 31 has a first control channel 33, and the second spring chamber 32 has a second control channel 34; the first connection port 43 is connected to the first control channel 33, and the second connection port 44 is connected to the second control channel 34; the first control channel 33 and the second control channel 34 are used to realize a wide range and precise control of the main valve core 3.

[0036] The pilot valve 4 also includes an electrical interface, which is arranged laterally on the pilot valve 4; the lateral access of the electrical interface can simplify the system integration work and avoid trampling damage; the traditional electrical interface of the pilot valve 4 is positioned above the pilot valve 4, which is easily damaged by being stepped on during daily use. In this regard, the electrical interface inside the pilot valve 4 is optimized to avoid possible trampling damage during installation and use.

[0037] A safety valve 5 is also provided between the main valve body 1 and the pilot valve 4 to control the oil conduction of the pilot oil circuit between the pilot valve 4 and the main valve body 1. The safety valve 5 is a plunger slide valve, and a preload spring is added to the structure of the plunger slide valve; when the pressure of the pilot oil circuit changes, the displacement on both sides of the plunger slide valve is used to achieve stable control of the pilot pressure; even if there is a power outage, the plunger slide valve keeps the valve core of the plunger slide valve in the middle position under the action of the preload spring. The added safety valve 5 is a plunger slide valve type with a built-in preload spring, which ensures the stability of the pilot oil circuit pressure and can keep the valve core in the middle position even in the case of a power outage, thereby enhancing the reliability of the system; the added safety valve 5 not only controls the oil conduction, but also maintains the system stability under extreme conditions through the preload spring. The connection of the reversing valve adopts a high-pressure, wear-resistant, high-performance sealing ring made of hydrogenated nitrile rubber (HNBR) to ensure the sealing reliability under high-pressure working conditions, prevent leakage, and extend the service life.

[0038] Embodiment 2

[0039] See also Figure 5 , the positive coverage of the first oil inlet 24 is 20%, and the negative coverage of the first oil return port 25 is 15%; the oil of the first oil inlet 24 flows to the first output port 21 and the second output port 22; the oil of the second output port 22 flows to the first oil return port 25 and the third output port 23; the oil of the first output port 21 flows to the first oil return port 25. The ratio of the oil of the first oil inlet 24 flowing to the first output port 21 and the second output port 22 is 1:2; the flow rate of the oil of the first output port 21 flowing to the first oil return port 25 is A, and the flow rate of the oil of the first oil inlet 24 flowing to the first output port 21 is B, A:B=1:2.

[0040] Specifically, the positive coverage rate of the first oil inlet 24 is 20%, and the negative coverage rate of the first oil return port 25 is 15%. Through this design, the oil of the first oil inlet 24 flows into the first output port 21 and the second output port 22 in a ratio of 1:2, while the oil of the second output port 22 flows into the first oil return port 25 and the third output port 23, and the oil of the first output port 21 flows back to the first oil return port 25, thereby achieving precise control of the flow rate and optimization of the differential function. This flow distribution mechanism improves the response speed and stability of the hydraulic system and reduces the loss of hydraulic energy.

[0041] The technical effects of the present invention are mainly reflected in the following aspects: the reversing valve can effectively solve the problem of insufficient liquid replenishment of the rodless cavity in the differential mold locking process of the large flow servo valve in the prior art through the third working chamber 13, ensure the effective use of the regenerated liquid, avoid the waste of hydraulic energy, and reduce the energy loss caused by the direct return of the regenerated liquid to the oil tank. The setting of the pilot valve 4 allows the reversing valve to achieve precise control of the main valve core 3 through a small amount of oil, which not only improves the control accuracy, but also improves the stability of the entire hydraulic system. This helps to eliminate the turbulence of the hydraulic oil flow and prevent the oil grabbing phenomenon, thereby ensuring the stability of the mold closing process, reducing the risk of mold collision, and extending the service life of the equipment. Through the design of the electromagnetic control unit and the spring chamber on both sides of the main valve body 1, a large range and precise control of the main valve core 3 is achieved, the synchronization between the valves is enhanced, and the synchronous response in the opening and closing and rapid mold shifting actions is ensured, solving the problem of uncoordinated switching and response of the two sets of valve bodies in the traditional solution. The lateral arrangement of the electrical interface simplifies the system integration work, reduces the risk of trampling damage during installation, and reduces the hardware cost and the difficulty of later maintenance.

[0042] In addition, as common knowledge in the industry, the electrical interface and plunger valve mentioned above are common knowledge, so their principles and structures will not be described in detail.

[0043] Of course, the above are only typical examples of the present invention. In addition, the present invention may also have many other specific implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims

1. A five-hole servo reversing valve with differential function, characterized in that: include: A main valve body, wherein the main valve body adopts a three-shoulder five-sink cut structure; the main valve body is provided with an oil chamber and an oil port; the oil chambers are respectively a first working chamber, a second working chamber, a third working chamber, an oil inlet chamber and an oil return chamber; the oil ports are respectively a first output port provided on the first working chamber, a second output port provided on the second working chamber, a third output port provided on the third working chamber, a first oil inlet port provided on the oil inlet chamber and a first oil return port provided on the oil return chamber; the third working chamber and the third output port are used to realize a differential function; Main valve core; the main valve core is located in the oil chamber; Pilot valve; the pilot valve is arranged on the main valve body, and a pilot oil circuit is formed between the pilot valve and the main valve body to drive the main valve core to move back and forth in the main valve body, so that the oil in the first oil inlet is connected to different oil ports respectively, so as to realize the reciprocating and differential reciprocating of the oil cylinder, and realize the opening and closing of the mold and the rapid mold shifting action; The second output port is connected to the rod chamber of the downstream component, and the first output port and the third output port merge to merge the high-pressure liquid and connect to the rodless chamber of the downstream component to achieve consistency of flow between the rodless chamber and the rod chamber; The main valve body has three working positions, namely, a middle position, a left position and a right position. The second working chamber and the third working chamber in the main valve body are switched between being connected and closed through the movement of the main valve core.

2. A five-hole servo reversing valve with differential function as claimed in claim 1, characterized in that: The pilot oil circuit includes a pilot oil inlet and a pilot oil return port provided on the main valve body, and the pilot valve has a second oil inlet and a second oil return port; the pilot oil inlet is connected to the second oil inlet, and the pilot oil return port is connected to the second oil return port; the pilot valve uses the pilot oil inlet to allow a small amount of oil to enter the main valve body to push the main valve core to move, and the oil then returns to the oil tank through the pilot oil return hole; A large range and precise control of the main valve core can be achieved with a small amount of oil.

3. A five-hole servo reversing valve with differential function as claimed in claim 1, characterized in that: The pilot valve is provided with a first connection port and a second connection port; the pilot valve comprises a pilot valve body and a pilot valve core; electromagnetic control units are provided at both ends of the pilot valve body to control the oil to flow out from the first connection port or the second connection port after passing through the second oil inlet; a first spring chamber and a second spring chamber are respectively provided on both sides of the main valve body, the first spring chamber has a first control channel, and the second spring chamber has a second control channel; the first connection port is connected to the first control channel, and the second connection port is connected to the second control channel; the first control channel and the second control channel are used to realize a wide range and precise control of the main valve core.

4. A five-hole servo reversing valve with differential function as claimed in claim 1, characterized in that: The pilot valve further comprises an electrical interface, which is arranged laterally on the pilot valve; the lateral access of the electrical interface can simplify system integration work and avoid trampling damage.

5. A five-hole servo reversing valve with differential function as claimed in claim 1, characterized in that: A safety valve is also provided between the main valve body and the pilot valve to control the oil conduction of the pilot oil circuit between the pilot valve and the main valve body.

6. A five-hole servo reversing valve with differential function as claimed in claim 5, characterized in that: The safety valve is a plunger slide valve, and a pre-compression spring is added to the structure of the plunger slide valve; when the pilot oil circuit pressure changes, the displacement on both sides of the plunger slide valve is used to achieve stable control of the pilot pressure; Even if power is cut off, the plunger slide valve keeps the valve core of the plunger slide valve in the middle position under the action of the pre-compression spring.

7. A five-hole servo reversing valve with differential function as claimed in claim 1, characterized in that: The positive coverage of the first oil inlet is 20%, and the negative coverage of the first oil return port is 15%; The oil at the first oil inlet flows to the first output port and the second output port; the oil at the second output port flows to the first oil return port and the third output port; the oil at the first output port flows to the first oil return port.

8. A five-hole servo reversing valve with differential function as claimed in claim 7, characterized in that: The ratio of the oil from the first oil inlet to the first output port and the second output port is 1:2; the flow rate of the oil from the first output port to the first oil return port is A, and the flow rate of the oil from the first oil inlet to the first output port is B, A:B=1:2.

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