Proportional cartridge valve assembly and hydraulic system of die-casting machine

Abstract

The utility model provides a proportional cartridge valve assembly and a die-casting machine hydraulic system adopting the proportional cartridge valve assembly. The proportional cartridge valve assembly comprises a main valve and a pilot valve, and the main valve is provided with a pilot oil port, an oil tank connector, a control oil port, a first main oil port and a second main oil port. The pilot valve is provided with an oil inlet, an oil return port, a first working oil port and a second working oil port. At the first valve position of the pilot valve, the oil inlet is communicated with the first working oil port and the second working oil port, and the oil return port is cut off; at the second valve position of the pilot valve, the oil inlet is cut off, and the oil return port is communicated with the first working oil port and the second working oil port; one of the oil inlet and the oil return port is connected to the pilot oil port, the other one of the oil inlet and the oil return port is connected to the oil tank connector, and the first working oil port and the second working oil port converge and are connected to the control oil port.

Description

Technical Field

[0001] This application relates to a proportional cartridge valve assembly capable of rapid response, and a hydraulic system for a die-casting machine employing such a proportional cartridge valve assembly. Background Technology

[0002] In the field of hydraulic oil delivery, three-position four-way directional valves are frequently used. In some specific applications, such as when used as a pilot valve to control the main valve, only one of the two working ports of this directional valve needs to be used. Therefore, one working port is often blocked, leaving the other working port as the output port, thus converting the three-position four-way valve into a three-position three-way valve. In this case, in any working valve position, only one of the two flow paths within the valve functions, while the other is cut off and ineffective, resulting in waste. In hydraulic systems requiring high flow rates and rapid responses, using such a modified three-position three-way valve as a pilot valve may lead to a slow main valve response, failing to meet operational requirements. For example, in a die-casting machine hydraulic system, if the main valve opens slowly, the molten metal (such as molten aluminum) injected into the die-casting mold may cool prematurely, losing its fluidity and failing to fill the mold cavity. Utility Model Content

[0003] One object of this application is to provide a proportional cartridge valve assembly that can improve the response time of a cartridge valve as a main valve.

[0004] To this end, this application provides a proportional cartridge valve assembly in one aspect, comprising a main valve and a pilot valve; the main valve is a cartridge valve having a pilot port, a tank interface, a control port, a first main port, and a second main port; the pilot port is connected to a hydraulic oil source, the tank interface is connected to an oil tank, and the oil pressure in the control port controls the on / off connection between the first main port and the second main port; the pilot valve is a proportional directional valve having an inlet port, a return port, a first working port, and a second working port; the pilot valve has a first valve position and a second valve position; in the first valve position, the inlet port is connected to both the first and second working ports, and the return port is cut off; in the second valve position, the inlet port is cut off, and the return port is connected to both the first and second working ports; one of the inlet port and the return port is connected to the pilot port, and the other of the inlet port and the return port is connected to the tank interface; the first and second working ports are connected together to the control port.

[0005] In one embodiment, the main valve is a cover-type cartridge valve, including a control cover and a valve body assembled on the control cover; the pilot port, the tank interface and the control port are formed on the control cover, and the first main port and the second main port are formed on the valve body.

[0006] In one embodiment, the pilot valve has an installation interface, on which the oil inlet, oil return, first working oil port, and second working oil port are formed, and the pilot valve is assembled onto the control cover plate through the installation interface.

[0007] In one embodiment, a control oil hole is formed in the control cover plate, which communicates with the first working oil port and the second working oil port respectively, and the control oil hole leads to the control oil port.

[0008] In one embodiment, the oil inlet is connected to the pilot oil inlet through the oil inlet hole in the control cover plate, and the oil return port is connected to the oil tank interface through the oil return hole in the control cover plate.

[0009] In one embodiment, the oil return port includes a first oil return port and a second oil return port formed on the mounting interface, and the first oil return port and the second oil return port are connected to each other through an internal channel in the valve body of the pilot valve.

[0010] In one embodiment, in the second valve position of the pilot valve, the first return port is connected to the first working port, and the second return port is connected to the second working port.

[0011] In one embodiment, the pilot valve further has an intermediate valve position, in which a throttling connection is formed between the oil inlet and / or oil return port and the first working oil port and / or the second working oil port.

[0012] In one embodiment, one of the first main oil port and the second main oil port is connected to the hydraulic oil source, and the other is connected to the load.

[0013] In another aspect, this application provides a hydraulic system for a die-casting machine, which includes a proportional cartridge valve assembly of this application. The pilot port of the main valve of the proportional cartridge valve assembly is connected to a hydraulic pump. One of the first main port and the second main port of the main valve is connected to the hydraulic pump, and the other is connected via a main oil circuit to the rodless chamber of the die-casting cylinder of the die-casting machine.

[0014] According to the proportional cartridge valve assembly of this application, the two working chambers of the proportional directional valve, which serves as the pilot valve, are combined to provide a single working oil passage. In either working position of the pilot valve, both flow passages within the valve are utilized for hydraulic oil transmission within the valve, improving the hydraulic oil transmission capacity of the pilot valve and thus increasing the response speed of the proportional cartridge valve as the main valve.

[0015] When the proportional cartridge valve assembly of this application is used in the hydraulic system of a die-casting machine, the response speed of the hydraulic system, especially the opening speed, can be improved, so that the molten metal can quickly fill the mold cavity, thereby improving the product qualification rate. Attached Figure Description

[0016] The foregoing and other aspects of this application will be more fully understood and appreciated through the following detailed description with reference to the accompanying drawings, in which:

[0017] Figure 1 This is a hydraulic schematic diagram of an exemplary proportional cartridge valve assembly according to this application;

[0018] Figure 2 This is a cross-sectional view of an exemplary structure of a proportional directional valve that can be used in the proportional cartridge valve assembly of this application;

[0019] Figure 3 , Figure 4 They are Figure 1 Hydraulic schematic diagram of the proportional cartridge valve assembly in two working states;

[0020] Figure 5 This is a hydraulic schematic diagram of the application of the proportional cartridge valve assembly in the hydraulic system of a die-casting machine according to this application;

[0021] Figure 6 This is a hydraulic schematic diagram of a modified proportional cartridge valve assembly according to this application. Detailed Implementation

[0022] This application generally relates to a proportional cartridge valve assembly for controlling the delivery of hydraulic oil, and an exemplary configuration of the proportional cartridge valve assembly is described in... Figure 1 As shown in the image.

[0023] like Figure 1 As shown, the proportional cartridge valve assembly includes a main valve 1 and a pilot valve 2.

[0024] Figure 1 One specific form of the main valve 1 shown is a cover-type proportional cartridge valve. This cover-type proportional cartridge valve can adopt an existing structure, so its composition and function will only be briefly described below.

[0025] The main valve 1 includes a control cover plate 11 and a valve body 12 assembled on the control cover plate 11. The control cover plate 11 has a pilot port X, a tank interface Y, and a control port Z. The pilot port X is connected to the output end of the hydraulic pump 3 (hydraulic oil source). The output end of the hydraulic pump 3 is also connected to a safety valve 4. The tank interface Y is connected to the oil tank.

[0026] A valve body 12 defines a valve cavity, in which a valve core 13 is slidably arranged. The valve cavity portion located on the back side of the valve core 13 is a back valve cavity (upper valve cavity) 14, and a control port Z is connected to the back valve cavity 14. A spring is provided in the back valve cavity 14 to push the valve core 13 forward. On the front side of the valve core 13, a first main oil port a and a second main oil port b are formed in the valve body 12. When the valve core 13 is in its foremost position, the connection between the first main oil port a and the second main oil port b is severed. Moving the valve core 13 backward allows the first main oil port a and the second main oil port b to connect. The first main oil port a is connected to the output end of the hydraulic pump 3, and the second main oil port b is connected to the load (…) via the main oil passage L. Figure 1 (Not shown in the image). It should be noted that the first main oil port a and the second main oil port b can be used interchangeably. That is, the first main oil port a is connected to the load through the main oil circuit L, while the second main oil port b is connected to the output end of the hydraulic pump 3.

[0027] Figure 1 One specific form of the pilot valve 2 shown is a plate-type proportional directional valve, which is assembled onto the control cover plate 11. The pilot valve 2 is a three-position four-way directional valve with three valve positions and four ports. The three valve positions are: first valve position, second valve position, and intermediate valve position. The four ports are: P port (inlet), T port (return port), A port (first working port), and B port (second working port). A return spring is provided on the first control end of the pilot valve 2, and an electromagnet is provided on the second control end. An adjustable drive current can be applied to the electromagnet to generate a thrust against the return spring.

[0028] In the intermediate valve position of pilot valve 2, a throttling connection is formed between some or all of ports P, T, A, and B. In the first valve position, port P is connected to both ports A and B, while port T is cut off. In the second valve position, port T is connected to both ports A and B, while port P is cut off.

[0029] Ports P, T, A, and B are all formed on the mounting interface of pilot valve 2. This mounting interface is fitted to the control cover plate 11, thereby assembling pilot valve 2 onto main valve 1. In the assembled state, port P is connected to pilot oil port X through the oil inlet hole formed in the control cover plate 11, and port T is connected to oil tank interface Y through the oil return hole formed in the control cover plate 11.

[0030] Ports A and B converge to lead to the back valve chamber 14 of the main valve 1. As a specific example, control oil holes communicating with ports A and B respectively can be formed in the control cover plate 11, and these control oil holes all lead to control oil port Z, thereby connecting ports A and B to the back valve chamber 14.

[0031] For those skilled in the art, it is technically easy to drill holes in the control cover plate 11 to create various oil holes and flow channels.

[0032] As pilot valve 2, in some existing types of plate-type proportional directional valves, a single T-port is formed on the mounting interface. In this case, the T-port communicates with the oil tank interface Y via a return oil hole formed in the control cover plate 11 leading to the oil tank interface Y. In other existing types of plate-type proportional directional valves, the T-port includes a pair of return oil ports formed on the mounting interface, referred to as the Ta port and the Tb port. In this case, return oil holes communicating with the Ta port and the Tb port respectively can be formed in the control cover plate 11, and these return oil holes lead to the oil tank interface Y, thereby connecting both the Ta port and the Tb port to the oil tank interface Y.

[0033] The following reference Figure 2 An exemplary structure of the pilot valve 2 is described. Figure 2 The intermediate valve position of pilot valve 2 is shown. See below. Figure 2 The pilot valve 2 includes a valve body 21 and a single valve core 22 disposed within the valve body 21. Valve position switching is achieved by controlling the position of the valve core 22 within the valve body 21.

[0034] A valve body 21 defines an axially extending valve chamber, within which a valve core 22 is axially slidably mounted. The valve body 21 forms a shape along the valve chamber from an axial first side (…). Figure 2 (middle left) towards the second side of the axis ( Figure 2 The valve body 21 is configured with the following chambers in sequence (from right to left): Ta chamber (first return oil chamber), A chamber (first working oil chamber), P chamber (inlet oil chamber), B chamber (second working oil chamber), and Tb chamber (second return oil chamber). Cavities P, A, and B are connected to ports P, A, and B, respectively. Cavities Ta and Tb are connected to ports Ta and Tb, respectively. Furthermore, the Ta and Tb chambers are interconnected within the valve body 21 via internal channels. The naming convention for these ports and chambers is conventional in the art. In the following description, mentioning connection (or disconnection) to a particular oil chamber implies connection (or disconnection) to the corresponding oil port.

[0035] On the outer periphery of valve core 22, along the axial first side ( Figure 2 From the left side of the middle to the second side of the axis ( Figure 2 Looking from the right side, the first to fifth oil grooves (cutting grooves) 2a, 2b, 2c, 2d, and 2e are formed sequentially. These oil grooves separate the valve core 22 body into valve core sections from the first axial side to the second axial side.

[0036] exist Figure 2 In the intermediate valve position of the pilot valve 2 shown, the first oil groove 2a faces the Ta chamber, the second oil groove 2b faces the A chamber, the third oil groove 2c faces the P chamber, the fourth oil groove 2d faces the B chamber, and the fifth oil groove 2e faces the Tb chamber. Adjacent oil chambers are connected by throttling grooves formed on the outer periphery of their respective valve core sections. Thus, the oil ports of the pilot valve 2 are interconnected by throttling.

[0037] The pilot valve 2 is driven from the first axial side to the second axial side by the valve core 22, achieving the first valve position. In the first valve position, the second oil groove 2b connects chamber A and chamber P, and the third oil groove 2c connects chamber B and chamber P. The valve core section between the first oil groove 2a and the second oil groove 2b isolates chamber Ta from chamber A, and the valve core section between the fourth oil groove 2d and the fifth oil groove 2e isolates chamber Tb from chamber B. Thus, the P port of the pilot valve 2 is connected to both port A and port B through two flow channels existing within the valve at this time (i.e., the flow channel from port P to port A, and the flow channel from port P to port B), meaning that port P is connected to both port A and port B. At this time, port T is cut off.

[0038] The second valve position of the pilot valve 2 is achieved by driving the valve core 22 from the second axial side to the first axial side. In the second valve position, the second oil groove 2b connects chamber A and chamber Ta, and the fifth oil groove 2e connects chamber B and chamber Tb. The valve core section between the second oil groove 2b and the third oil groove 2c, and the valve core section between the third oil groove 2c and the fourth oil groove 2d, respectively isolate chamber P from chambers A and B. Thus, the Ta port and Tb port of the pilot valve 2 are connected to ports A and B respectively through two flow channels existing in the valve at this time (i.e., the flow channel from port Ta to port A, and the flow channel from port Tb to port B), that is, port T is connected to ports A and B. At this time, port P is cut off.

[0039] It should be noted that when the pilot valve 2 is a proportional valve, the opening degree of each valve position depends on the magnitude of the current applied to the electromagnet at the second control terminal.

[0040] Back Figure 1 And refer to Figure 2 When the electromagnet at the second control end of the pilot valve 2 is de-energized, the spring at the first control end of the pilot valve 2 pushes the valve core 22 to the first valve position, connecting port P with ports A and B, while port T (Ta port + Tb port) is cut off. The hydraulic oil output from the hydraulic pump 3 flows into port P of the pilot valve 2 through the pilot port X of the main valve 1, flows to ports A and B within the pilot valve 2, and then converges through the control oil hole in the control cover plate 11 to flow to control port Z, and then enters the back valve chamber 14 through control port Z, pushing the valve core 13 of the main valve 1 to the foremost position. The connection between the first main oil port a and the second main oil port b is cut off, the main valve 1 is closed, and the main oil circuit L is disconnected from the hydraulic pump 3, preventing the supply of hydraulic oil output from the hydraulic pump 3 to the load.

[0041] When the electromagnet at the second control terminal of pilot valve 2 is supplied with the maximum control current, the electromagnet overcomes the spring at the first control terminal of pilot valve 2 and pushes the valve core 22 to the second valve position, as shown below. Figure 3As shown. At this time, port P is cut off, and port T (Ta port + Tb port) is connected to ports A and B. The oil pressure in the back valve chamber 14 is released to the oil tank through the control port Z via ports A and B, then through port T and the oil tank interface Y, realizing the depressurization of the back valve chamber 14. The first main oil port a, which is connected to the output end of the hydraulic pump 3, receives the output oil pressure of the hydraulic pump 3 and pushes the valve core 13 to the back side, so that the first main oil port a and the second main oil port b are connected at the maximum opening, the main valve 1 is opened, and the main oil circuit L is connected to the output end of the hydraulic pump 3. The main oil circuit L can supply the hydraulic oil output by the hydraulic pump 3 to the load at the maximum flow rate.

[0042] With an intermediate control current flowing through the electromagnet at the second control terminal of pilot valve 2, the valve core 22 is pushed to the intermediate valve position under the action of the spring at the first control terminal of pilot valve 2, as shown below. Figure 4 As shown. At this time, the P port and T port are critically connected. The hydraulic oil output by the hydraulic pump 3 flows into the P port of the pilot valve 2 through the pilot port X of the main valve 1. Part of the hydraulic oil at the P port flows to the A and B ports, and then enters the back valve chamber 14 through the control port Z; the other part of the hydraulic oil at the P port flows to the oil tank through the T port and the oil tank interface Y, and the oil pressure in the back valve chamber 14 decreases. On the other hand, the hydraulic oil output by the hydraulic pump 3 acts on the valve core 13 through the first main port a. The pressure in the first main port a is balanced with the pressure in the back oil chamber and the return spring force, so that the valve core 13 is in the middle position. The first main port a and the second main port b are connected with an intermediate opening less than the maximum opening, so that the main oil circuit L can supply the hydraulic oil output by the hydraulic pump 3 to the load with an intermediate flow rate less than the maximum flow rate.

[0043] As can be seen, in the proportional cartridge valve assembly according to this application, the pilot valve 2 has two internal flow channels existing in parallel in both the first and second valve positions, which are simultaneously used to deliver hydraulic oil. Therefore, compared with the prior art solution of blocking one working port of a three-position four-way valve, the pilot valve 2 of this application does not waste flow channels and can fully utilize the two parallel flow channels within the valve to provide greater flow capacity. Compared with a standard three-position three-way valve, the pilot valve 2 of this application can also utilize the two parallel flow channels within the valve to provide greater flow capacity. Because the pilot valve 2 can provide a larger flow rate, the opening action of the main valve can be accelerated, and the closing action can also be accelerated. This is very advantageous for applications that require a fast main valve response, especially a fast opening response.

[0044] Furthermore, since the flow capacity of pilot valve 2 is increased, a smaller pilot valve can be selected for the same application. This reduces costs, and since smaller pilot valves typically have a faster response time, this further shortens the response time of main valve 1.

[0045] As one application scenario of the proportional cartridge valve assembly of this application, the proportional cartridge valve assembly is used to constitute the hydraulic system of a die-casting machine. For example... Figure 5 As shown, a check valve 5 is installed in the main oil circuit L, ensuring that the hydraulic oil in the main oil circuit L can only flow towards the load side. The main oil circuit L leads to the die-casting cylinder 6 (load) of the die-casting machine. The die-casting cylinder 6 contains a die-casting piston 7, the piston rod of which is used to die-cast molten metal, such as molten aluminum, into the mold cavity 9 of the die-casting mold 8. The end of the main oil circuit L is connected to the rodless chamber of the die-casting cylinder 6. In addition, a booster 10 can be equipped for the rodless chamber of the die-casting cylinder 6. This application does not involve improvements to the die-casting machine and the die-casting mold 8, and therefore will not describe them further. When the proportional cartridge valve assembly of this application is used in the hydraulic system of the die-casting machine, the pushing speed of the die-casting piston 7 can be increased, allowing the molten metal in the die-casting machine to be pushed into the mold cavity 9 of the die-casting mold 8 more quickly, preventing the molten metal from cooling prematurely, and improving the yield of die-cast parts.

[0046] It is understood that the proportional cartridge valve assembly of this application can also be used in other fields where it is necessary to improve the response speed of the main valve.

[0047] Returning to the proportional cartridge valve assembly of this application, in order to further improve the flow capacity of the pilot valve 2, according to one design scheme, the flow area of ​​port P on the mounting interface of the pilot valve 2 is set to the sum of the flow areas of ports A and B. This reduces the pressure drop from port P to ports A and B in the first valve position, thereby improving the flow capacity of the pilot valve 2.

[0048] Furthermore, in some applications, the T port and P port of pilot valve 2 can be used in reverse, such as... Figure 6 As shown. In this case, port T connects to pilot port X, which is also connected to the output end of hydraulic pump 3. Port P connects to tank interface Y, which is also connected to the tank. Ports A and B combine to connect to control port Z. Figure 6 In the second valve position shown, the T port of the pilot valve 2 is connected to the A port and the B port respectively through two flow channels existing in the valve at this time. This improves the flow capacity of the pilot valve 2, that is, it improves the ability of the hydraulic pump 3 to supply oil pressure to the back valve chamber 14 through the pilot port X, the T port, the A port and the B port, and the control port Z, thereby improving the response speed of the main valve 1, especially the closing response speed. When the T port is composed of the Ta port and the Tb port on the mounting interface, return oil holes are formed in the control cover plate 11 of the main valve 1, which are connected to the Ta port and the Tb port respectively. And the return oil holes all lead to the pilot port X, thereby connecting the Ta port and the Tb port to the pilot port X. This can further improve the response speed of the main valve 1.

[0049] While this application has been described herein with reference to specific exemplary embodiments, the scope of this application is not limited to the details shown. Various modifications may be made to these details without departing from the basic principles of this application.

Claims

1. A proportional cartridge valve assembly, comprising a main valve (1) and a pilot valve (2); Its features are, The main valve (1) is a cartridge valve, having a pilot port (X), a tank interface (Y), a control port (Z), a first main port (a), and a second main port (b). The pilot port (X) is connected to a hydraulic oil source, the tank interface (Y) is connected to an oil tank, and the oil pressure in the control port (Z) controls the connection and disconnection between the first main port (a) and the second main port (b). The pilot valve (2) is a proportional directional valve, having an oil inlet (P), an oil return port (T), a first working oil port (A), and a second working oil port (B); The pilot valve (2) has a first valve position and a second valve position; in the first valve position, the oil inlet (P) is connected to both the first working oil port (A) and the second working oil port (B), and the oil return port (T) is cut off; in the second valve position, the oil inlet (P) is cut off, and the oil return port (T) is connected to both the first working oil port (A) and the second working oil port (B); One of the oil inlet (P) and the oil return (T) is connected to the pilot oil port (X), and the other of the oil inlet (P) and the oil return (T) is connected to the oil tank interface (Y). The first working oil port (A) and the second working oil port (B) are connected to the control oil port (Z).

2. The proportional cartridge valve assembly as described in claim 1, characterized in that, The main valve (1) is a cover-type cartridge valve, including a control cover plate (11) and a valve body (12) assembled on the control cover plate (11); the pilot port (X), the tank interface (Y) and the control port (Z) are formed on the control cover plate (11), and the first main port (a) and the second main port (b) are formed on the valve body (12).

3. The proportional cartridge valve assembly as described in claim 2, characterized in that, The pilot valve (2) has an installation interface, and the oil inlet (P), oil return (T), first working oil port (A) and second working oil port (B) are formed on the installation interface. The pilot valve (2) is assembled on the control cover plate (11) through the installation interface.

4. The proportional cartridge valve assembly as described in claim 3, characterized in that, The control cover plate (11) forms control oil holes that communicate with the first working oil port (A) and the second working oil port (B) respectively, and the control oil holes lead to the control oil port (Z).

5. The proportional cartridge valve assembly as described in claim 3, characterized in that, The oil inlet (P) is connected to the pilot oil inlet (X) through the oil inlet hole in the control cover plate (11), and the oil return port (T) is connected to the oil tank interface (Y) through the oil return hole in the control cover plate (11).

6. The proportional cartridge valve assembly as described in claim 3, characterized in that, The return port (T) includes a first return port (Ta) and a second return port (Tb) formed on the mounting interface. The first return port (Ta) and the second return port (Tb) are connected to each other through an internal channel in the valve body of the pilot valve (2).

7. The proportional cartridge valve assembly as described in claim 6, characterized in that, In the second valve position of the pilot valve (2), the first return port (Ta) is connected to the first working port (A), and the second return port (Tb) is connected to the second working port (B).

8. The proportional cartridge valve assembly as described in any one of claims 1-7, characterized in that, The pilot valve (2) also has an intermediate valve position in which a throttling connection is formed between the oil inlet (P) and / or the oil return (T) and the first working oil port (A) and / or the second working oil port (B).

9. The proportional cartridge valve assembly as described in any one of claims 1-7, characterized in that, One of the first main oil port (a) and the second main oil port (b) is connected to the hydraulic oil source, and the other is connected to the load.

10. A hydraulic system for a die-casting machine, characterized in that, The proportional cartridge valve assembly includes any one of claims 1-9, wherein the pilot port (X) of the main valve (1) of the proportional cartridge valve assembly is connected to the hydraulic pump (3), and one of the first main port (a) and the second main port (b) of the main valve (1) is connected to the hydraulic pump (3), and the other is connected to the rodless chamber of the die-casting cylinder (6) of the die-casting machine via the main oil passage (L).

Images