High-speed oil supplementing system of hydraulic oil cylinder and injection molding machine

Abstract

The invention discloses a hydraulic oil cylinder high-speed oil supplementing system and an injection molding machine, and belongs to the technical field of injection molding machine hydraulic systems, the hydraulic oil cylinder high-speed oil supplementing system comprises an oil cylinder, a control oil way, an oil supply loop and an oil tank, the control oil way is communicated with the oil cylinder, one end of the oil supply loop is communicated with the control oil way, and the other end of the oil supply loop is communicated with the oil tank; the control oil way comprises a first cartridge valve, a second cartridge valve, a third cartridge valve, a fourth cartridge valve, a first electromagnetic valve, a second electromagnetic valve and a third electromagnetic valve, one end of the first cartridge valve is communicated with a rodless cavity of the oil cylinder, the other end of the first cartridge valve is communicated with the oil tank, one end of the second cartridge valve is communicated with the rodless cavity of the oil cylinder, and the other end of the second cartridge valve is connected with the oil supply loop. The first electromagnetic valve controls opening and closing of the first cartridge valve and the second cartridge valve, the first cartridge valve and the second cartridge valve act asynchronously, one end of the third cartridge valve is communicated with a rod cavity of the oil cylinder, the other end of the third cartridge valve is connected with an oil supply loop, one end of the fourth cartridge valve is communicated with a rod cavity of the oil cylinder, and the other end of the fourth cartridge valve is connected with an oil tank. The second solenoid valve controls opening and closing of the third cartridge valve, the third solenoid valve controls opening and closing of the fourth cartridge valve, the third cartridge valve and the fourth cartridge valve act asynchronously, and the four cartridge valves are combined directly to control oil inlet and oil return of the oil cylinder, so that the length of the moving distance of hydraulic oil is shortened, and the flowing resistance of the hydraulic oil is reduced; and the action sensitivity of the oil cylinder is improved, so that the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic systems for injection molding machines, and in particular to a hydraulic cylinder high-speed oil replenishing system and an injection molding machine. Background Art

[0002] High-speed injection molding machines mainly refer to injection molding machines with speeds exceeding 300mm / s. This type of injection molding machine is mainly used to mold thin-walled plastic products. In order to achieve such a high injection speed, the injection circuit uses an accumulator to increase the injection speed. However, the accumulator needs to store energy and has a slow reaction speed, which does not meet the requirements of high-speed injection. The existing electric melt injection molding machines using traditional oil circuits generally have a delay problem of loosening and retreating after melting. The loosening and retreating immediately after melting generally take place after 20s-40s. The specific time depends on the size of the injection cylinder and the length of the melting stroke, which seriously affects the efficiency of the machine in producing products. In addition, the oil circuit for hydraulic oil replenishment also has the problem of inaccurate control of the melt back pressure. The pressure and flow of the oil replenishment hydraulic source are uncontrollable, resulting in uncontrollable melt back pressure and instability during loosening and retreating, which will affect the quality and efficiency of the machine's products and have high energy consumption. In addition, the return oil of a general injection molding machine must pass through a cooler before returning to the oil tank. The cooling part will produce a large liquid resistance when absorbing oil, and it is impossible to smoothly absorb oil into the injection cavity of the injection cylinder. Therefore, a hydraulic system that can quickly respond to the injection rod is needed.

[0003] The existing patent application with publication number CN114001059A discloses a V-shaped injection hydraulic oil circuit for an injection molding machine, including a system pressure oil inlet, an oil return port, a seat oil circuit, an injection oil circuit and a storage oil circuit. A two-way hydraulic lock, a first damper and a second damper are added to the seat oil circuit that drives the injection seat to move, so as to ensure the smoothness of the up and down movement of the injection seat and effectively maintain the position of the injection seat. A third electromagnetic reversing valve for replenishing oil to the injection cylinder is provided in the storage oil circuit, and a one-way valve is provided between the storage oil circuit and the oil return port. The one-way valve is also located between the injection oil circuit and the oil return port. The one-way valve can provide return oil back pressure for the third electromagnetic reversing valve and the injection cylinder. When the hydraulic oil circuit is replenished with oil, the oil resistance is large and there is a delay in action. Summary of the invention

[0004] One of the purposes of the present invention is to provide a high-speed oil replenishment system for a hydraulic cylinder, which solves the problems of large oil replenishment resistance and high action delay in the existing hydraulic system.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0006] A high-speed oil replenishment system for a hydraulic cylinder comprises an oil cylinder, a control oil circuit, an oil supply circuit and an oil tank, wherein the control oil circuit is connected to the oil cylinder, one end of the oil supply circuit is connected to the control oil circuit, and the other end is connected to the oil tank, the control oil circuit comprises a first cartridge valve, a second cartridge valve, a third cartridge valve, a fourth cartridge valve, a first solenoid valve, a second solenoid valve and a third solenoid valve, one end of the first cartridge valve is connected to the rodless chamber of the oil cylinder, and the other end is connected to the oil tank, one end of the second cartridge valve is connected to the rodless chamber of the oil cylinder, and the other end is connected to the oil supply circuit, and the first solenoid valve controls the opening and closing of the first cartridge valve and the second cartridge valve , the first cartridge valve and the second cartridge valve act asynchronously, one end of the third cartridge valve is connected to the rod chamber of the oil cylinder, and the other end is connected to the oil supply circuit, one end of the fourth cartridge valve is connected to the rod chamber of the oil cylinder, and the other end is connected to the oil tank, the second solenoid valve controls the opening and closing of the third cartridge valve, and the third solenoid valve controls the opening and closing of the fourth cartridge valve, the third cartridge valve and the fourth cartridge valve act asynchronously, and the four cartridge valves are directly combined to control the oil inlet and return of the oil cylinder, which shortens the length of the hydraulic oil moving distance and reduces the resistance to the flow of hydraulic oil. The action sensitivity of the oil cylinder is improved, thereby improving production efficiency.

[0007] Furthermore, the control oil circuit also includes a pilot overflow valve and a proportional overflow valve, one end of the pilot overflow valve is connected to the third solenoid valve, and the other end is connected to one end of the proportional overflow valve, and the other end of the proportional overflow valve is connected to the oil tank for setting the pressure of the overflow return oil.

[0008] Preferably, the first solenoid valve and the second solenoid valve are two-position two-way valves for oil switching, the third solenoid valve is a two-position three-way valve for oil switching and stopping, and the first solenoid valve remotely controls the on and off of the first cartridge valve to control the opening and closing of the cartridge valve to achieve oil inlet and oil return.

[0009] Furthermore, the control oil circuit also includes a reversing solenoid valve, one end of which is connected to the second solenoid valve and the other end of which is connected to the oil tank for pressure relief during injection.

[0010] Furthermore, the oil supply circuit includes a first oil pump, a first servo-controller, a second oil pump and a second servo-controller, one end of the first oil pump is connected to the oil tank, and the other end is connected to the control oil circuit, the first servo-controller controls the opening and closing of the first oil pump, one end of the second oil pump is connected to the oil tank, and the other end is connected to the control oil circuit, the second servo-controller is used to control the opening and closing of the second oil pump, and to provide sufficient hydraulic oil to the oil cylinder.

[0011] Preferably, the first oil pump and the second oil pump are double pumps, and the first oil pump and the second oil pump are connected in parallel to prevent insufficient oil quantity and oil pressure.

[0012] Furthermore, it also includes a cooling system, which is connected to the first oil pump and the second oil pump. The hydraulic oil does not return through the cooling system, and the hydraulic oil circulates between the cooling system and the oil tank to complete cooling.

[0013] Furthermore, the cooling system includes a filter, a cooler and a third oil pump, one end of the filter is connected to the oil supply circuit, and the other end is connected to one end of the cooler, the other end of the cooler is connected to one end of the third oil pump, and the other end of the third oil pump is connected to the oil tank for filtering and cooling the hydraulic oil.

[0014] Preferably, the cooling system also includes a cooling one-way valve, one end of the cooling one-way valve is connected to the oil supply circuit, and the other end of the cooling one-way valve is connected to the oil tank. The cooling one-way valve is connected in parallel with the cooler to form an oil return branch for diversion when cooling the hydraulic oil.

[0015] The second object of the present invention is to provide an injection molding machine, which solves the problem of large delay in control of the injection rod of the existing injection molding machine, resulting in low production efficiency.

[0016] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0017] An injection molding machine comprises a hydraulic cylinder high-speed oil replenishment system and a glue injection screw. The hydraulic cylinder high-speed oil replenishment system provides power for the action of the glue injection screw, which can move quickly when loosening and retracting, thereby improving production efficiency.

[0018] The beneficial effects of the present invention are:

[0019] (1) The control oil circuit on the hydraulic cylinder high-speed oil replenishment system includes multiple cartridge valves for opening and closing the oil circuit and multiple solenoid valves for controlling the oil circuit conversion state. When the cylinder is retreating, its rod chamber is supplied with oil by the oil supply circuit, and its rodless chamber is connected to the oil tank through the first cartridge valve. The rodless chamber can quickly absorb oil from the oil tank under negative pressure. The first cartridge valve is sensitive, and the resistance of oil entering the rodless chamber is small. When the cylinder moves forward, the rod chamber is controlled by the fourth cartridge valve to discharge oil. The fourth cartridge valve is sensitive, and the resistance of oil discharged from the rod chamber to the oil tank is small, thereby improving the sensitivity of the cylinder movement and reducing the impact of the cylinder movement.

[0020] (2) The control oil circuit of the hydraulic cylinder high-speed oil replenishment system is provided with a pilot relief valve and a proportional relief valve group oil discharge circuit, which can accurately control the pressure and flow of the discharged oil; a servo controller is used to control the oil supply circuit composed of two groups of oil pumps in parallel, and the redundant composition can ensure the stability of the oil inlet pressure and flow; in addition, an independent cooling system is also provided, which is connected to the oil supply circuit and can directly cool and filter the pumped oil. The cylinder does not pass through the cooling system when returning oil, which reduces the length of the oil return path and the resistance of the oil return, and further improves the sensitivity of the cylinder action. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A diagram of a high-speed oil replenishment system for a hydraulic cylinder provided by the present invention.

[0022] Reference numerals:

[0023] 1. Injection screw; 11. Motor; 2. Cylinder; 3. Control oil circuit; 31. First cartridge valve; 32. Second cartridge valve; 33. First solenoid valve; 34. Second solenoid valve; 35. Third cartridge valve; 36. Third solenoid valve; 37. Fourth cartridge valve; 38. Pilot relief valve; 381. Proportional relief valve; 39. Reversing solenoid valve; 4. Oil supply circuit; 41. First oil pump; 42. First servo controller; 43. Second oil pump; 44. Second servo controller; 5. Cooling system; 51. Cooler; 52. Third oil pump; 53. Filter; 54. Cooling check valve; 6. Oil tank. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Embodiment 1

[0026] like Figure 1As shown, the present embodiment discloses a high-speed oil replenishment system for a hydraulic cylinder, comprising an oil cylinder 2, a control oil circuit 3, an oil supply circuit 4 and an oil tank 6. The control oil circuit 3 is connected to the oil cylinder 2, one end of the oil supply circuit 4 is connected to the control oil circuit 3, and the other end is connected to the oil tank 6. The control oil circuit 3 comprises a first cartridge valve 31, a second cartridge valve 32, a third cartridge valve 35, a fourth cartridge valve 37, a first solenoid valve 33, a second solenoid valve 34 and a third solenoid valve 36. One end of the first cartridge valve 31 is connected to the rodless cavity of the oil cylinder 2, and the other end is connected to the oil tank 6. One end of the second cartridge valve 32 is connected to the rodless cavity of the oil cylinder 2, and the other end is connected to the oil supply circuit 4. The first solenoid valve 33 controls the opening and closing of the first cartridge valve 31 and the second cartridge valve 32. The first cartridge valve 3 1 and the second cartridge valve 32 act asynchronously, one end of the third cartridge valve 35 is connected to the rod chamber of the oil cylinder 2, and the other end is connected to the oil supply circuit 4, one end of the fourth cartridge valve 37 is connected to the rod chamber of the oil cylinder 2, and the other end is connected to the oil tank 6, the second solenoid valve 34 controls the opening and closing of the third cartridge valve 35, and the third solenoid valve 36 controls the opening and closing of the fourth cartridge valve 37. The third cartridge valve 35 and the fourth cartridge valve 37 act asynchronously, and the first cartridge valve 31, the second cartridge valve 32, the third cartridge valve 35 and the fourth cartridge valve 37 respectively complete the oil intake and oil discharge when the oil cylinder 2 moves forward and backward, and the back pressure side of the oil cylinder 2 can absorb oil with low resistance, which reduces the resistance of the hydraulic oil flow, improves the sensitivity of the action of the oil cylinder 2, and thus improves the efficiency of the action of the injection screw 1.

[0027] Among them, the first cartridge valve 31 is a normally open valve, which is used for negative pressure oil suction without resistance in the rodless chamber. When the first solenoid valve 33 is energized, the first cartridge valve 31 is closed, and the second cartridge valve 32 controls the oil flow into the rodless chamber of the cylinder 2, and the cylinder 2 completes the loosening action backward.

[0028] Furthermore, the control oil circuit 3 also includes a pilot relief valve 38 and a proportional relief valve 381. One end of the pilot relief valve 38 is connected to the third solenoid valve 36, and the other end is connected to one end of the proportional relief valve 381. The other end of the proportional relief valve 381 is connected to the oil tank 6. By adjusting the pilot relief valve 38 and the proportional relief valve 381, the opening pressure of the third solenoid valve 36 can be set, and the opening and closing of the fourth cartridge valve 37 is controlled by the third solenoid valve 36.

[0029] Preferably, the first solenoid valve 33 and the second solenoid valve 34 are two-position two-way valves for oil switching. Specifically, the first solenoid valve 33 remotely controls the on and off of the first cartridge valve 31 and directly controls the opening and closing of the second cartridge valve 32. The second solenoid valve 34 controls the opening and closing of the third cartridge valve 35. The third solenoid valve 36 is a two-position three-way valve for oil switching and stopping. Specifically, the third solenoid valve 36 controls the opening and closing of the fourth cartridge valve 37.

[0030] Furthermore, the control oil circuit 3 also includes a reversing solenoid valve 39, one end of which is connected to the second solenoid valve 34, and the other end is connected to the oil tank 6, which is used for direct pressure relief of the rod chamber of the oil cylinder 2, and for rapid pressure relief during the back pressure of the melt, injection and pressure holding process.

[0031] Furthermore, the oil supply circuit 4 includes a first oil pump 41, a first servo controller 42, a second oil pump 43 and a second servo controller 44. One end of the first oil pump 41 is connected to the oil tank 6, and the other end is connected to the control oil circuit 3. The first servo controller 42 controls the opening and closing of the first oil pump 41. One end of the second oil pump 43 is connected to the oil tank 6, and the other end is connected to the control oil circuit 3. The second servo controller 44 is used to control the opening and closing of the second oil pump 43. The first oil pump 41 and the second oil pump 43 are connected in parallel, and a one-way valve is provided at the oil supply end thereof for preventing the hydraulic oil from flowing back and for inputting hydraulic oil with sufficient pressure and flow into the oil cylinder 2. The servo system control is adopted to shorten the response time in the system.

[0032] Preferably, the first oil pump 41 and the second oil pump 43 are double pumps, in which one motor drives the two pumps to provide oil pressure to ensure sufficient hydraulic supply, and the first oil pump 41 and the second oil pump 43 are connected in parallel. Through the redundant design of the parallel oil pumps, the stability of the oil supply pressure and flow to the cylinder 2 can be guaranteed.

[0033] Furthermore, it also includes a cooling system 5, which is connected to the first oil pump 41 and the second oil pump 43. The first servo controller 42 and the second servo controller 44 control the first oil pump 41 and the second oil pump 43 to send oil to the cooling system 5. By directly sending the hydraulic oil in the oil tank 6 to the cooling system 5 for filtering and cooling, the hydraulic oil does not need to pass through the cylinder 2 and then flow back, which reduces the path length and resistance of the oil return from the cylinder 2 and improves the sensitivity of the action of the cylinder 2.

[0034] Furthermore, the cooling system 5 includes a filter 53, a cooler 51 and a third oil pump 52. One end of the filter 53 is connected to the oil supply circuit 4, and the other end is connected to one end of the cooler 51. The other end of the cooler 51 is connected to one end of the third oil pump 52. The other end of the third oil pump 52 is connected to the oil tank 6. The filter 53 is used to remove impurities in the hydraulic oil. The cooler 51 is used to reduce the temperature of the hydraulic oil. The third oil pump 52 is used to increase the power of the hydraulic oil circulation cooling to ensure the stability of the physical properties of the hydraulic oil.

[0035] Preferably, the cooling system 5 also includes a cooling check valve 54, one end of the cooling check valve 54 is connected to the oil supply circuit 4, and the other end of the cooling check valve 54 is connected to the oil tank 6. The cooling check valve 54 is connected in parallel with the cooler 51 to form an oil return branch, and the oil return branch is used to divert the hydraulic oil to prevent excessive hydraulic oil from damaging the cooler 51.

[0036] Embodiment 2

[0037] This embodiment also discloses an injection molding machine, including a hydraulic cylinder high-speed oil replenishment system and an injection screw 1. The hydraulic cylinder high-speed oil replenishment system provides power for the movement of the injection screw 1. The injection cylinder 2 is driven to rotate by the melt motor 11, and the cylinder 2 pushes the injection screw 1 to move forward and backward to complete the injection action.

[0038] The working process of the injection molding machine is as follows:

[0039] The motor 11 rotates to drive the injection screw 1 to rotate, and the molten plastic material gradually fills the barrel. The back pressure during the melting is first adjusted, that is, the reversing solenoid valve 39 is energized, the third solenoid valve 36 is energized, and the overflow pressure of the proportional relief valve 381 is set. The oil cylinder 2 pushes the screw backward, and the rodless cavity of the oil cylinder 2 forms a vacuum negative pressure. Under the suction of the negative pressure, the first cartridge valve 31 is normally open, and the hydraulic oil is sucked into the rodless cavity of the oil cylinder 2 and filled; after the injection screw 1 completes the melting of the glue, it is loosened and retracted, the first oil pump 41 and the second oil pump 43 are started, the first solenoid valve 33 is energized to change direction, the first cartridge valve 31 is closed, the second cartridge valve 32 is opened, and the hydraulic oil is fed from the rodless cavity of the oil cylinder 2, the third solenoid valve 36 is energized, and the fourth cartridge valve 37 is opened. The injection screw 1 is quickly loosened and retracted to the corresponding position. After the injection action is completed, the cooling system 5 cools the hydraulic oil in the oil tank 6 separately.

[0040] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also change and modify the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes of the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A high-speed oil replenishment system for a hydraulic cylinder, comprising an oil cylinder (2), a control oil circuit (3), an oil supply circuit (4) and an oil tank (6), wherein the control oil circuit (3) is connected to the oil cylinder (2), one end of the oil supply circuit (4) is connected to the control oil circuit (3), and the other end is connected to the oil tank (6), characterized in that: The control oil circuit (3) comprises a first cartridge valve (31), a second cartridge valve (32), a third cartridge valve (35), a fourth cartridge valve (37), a first solenoid valve (33), a second solenoid valve (34) and a third solenoid valve (36). One end of the first cartridge valve (31) is connected to the rodless chamber of the oil cylinder (2), and the other end is connected to the oil tank (6). One end of the second cartridge valve (32) is connected to the rodless chamber of the oil cylinder (2), and the other end is connected to the oil supply circuit (4). The first solenoid valve (33) controls the first cartridge valve (31) and the second cartridge valve (32). ), the first cartridge valve (31) and the second cartridge valve (32) act asynchronously, one end of the third cartridge valve (35) is connected to the rod chamber of the oil cylinder (2), and the other end is connected to the oil supply circuit (4), one end of the fourth cartridge valve (37) is connected to the rod chamber of the oil cylinder (2), and the other end is connected to the oil tank (6), the second solenoid valve (34) controls the opening and closing of the third cartridge valve (35), the third solenoid valve (36) controls the opening and closing of the fourth cartridge valve (37), and the third cartridge valve (35) and the fourth cartridge valve (37) act asynchronously.

2. The hydraulic cylinder high-speed oil replenishment system according to claim 1, characterized in that: The control oil circuit (3) further comprises a pilot overflow valve (38) and a proportional overflow valve (381); one end of the pilot overflow valve (38) is connected to the third solenoid valve (36), and the other end is connected to one end of the proportional overflow valve (381); and the other end of the proportional overflow valve (381) is connected to the oil tank (6).

3. The hydraulic cylinder high-speed oil replenishment system according to claim 2 is characterized in that: The first solenoid valve (33) and the second solenoid valve (34) are two-position two-way valves for oil switching, the third solenoid valve (36) is a two-position three-way valve for oil switching and stopping, and the first solenoid valve (33) remotely controls the on and off of the first cartridge valve (31).

4. The hydraulic cylinder high-speed oil replenishment system according to claim 1, characterized in that: The control oil circuit (3) further comprises a reversing solenoid valve (39), one end of which is connected to the second solenoid valve (34) and the other end of which is connected to the oil tank (6).

5. The hydraulic cylinder high-speed oil replenishment system according to any one of claims 1 to 4, characterized in that: The oil supply circuit (4) comprises a first oil pump (41), a first servo controller (42), a second oil pump (43) and a second servo controller (44); one end of the first oil pump (41) is connected to the oil tank (6), and the other end is connected to the control oil circuit (3); the first servo controller (42) controls the opening and closing of the first oil pump (41); one end of the second oil pump (43) is connected to the oil tank (6), and the other end is connected to the control oil circuit (3); the second servo controller (44) is used to control the opening and closing of the second oil pump (43).

6. The hydraulic cylinder high-speed oil replenishment system according to claim 5, characterized in that: The first oil pump (41) and the second oil pump (43) are double pumps, and the first oil pump (41) and the second oil pump (43) are connected in parallel.

7. The hydraulic cylinder high-speed oil replenishment system according to claim 5, characterized in that: It also includes a cooling system (5), which is in communication with the first oil pump (41) and the second oil pump (43).

8. The hydraulic cylinder high-speed oil replenishment system according to claim 7, characterized in that: The cooling system (5) comprises a filter (53), a cooler (51) and a third oil pump (52); one end of the filter (53) is connected to the oil supply circuit (4), and the other end is connected to one end of the cooler (51); the other end of the cooler (51) is connected to one end of the third oil pump (52); and the other end of the third oil pump (52) is connected to the oil tank (6).

9. The hydraulic cylinder high-speed oil replenishment system according to claim 8, characterized in that: The cooling system (5) further comprises a cooling one-way valve (54), one end of which is connected to the oil supply circuit (4), and the other end of which is connected to the oil tank (6). The cooling one-way valve (54) is connected in parallel with the cooler (51) to form an oil return branch.

10. An injection molding machine, comprising the hydraulic cylinder high-speed oil replenishment system according to any one of claims 1 to 9 and an injection screw (1), wherein the hydraulic cylinder high-speed oil replenishment system provides power for the movement of the injection screw (1).

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