Sub and main cylinder with pressure maintaining function

Abstract

This invention relates to a master cylinder with a pressure-holding function, comprising a master cylinder, a slave cylinder disposed within the master cylinder with its outer end extending out of the master cylinder, and a piston rod disposed within the master cylinder with its inner end extending into the slave cylinder. The slave cylinder is coaxially placed with the master cylinder, and the inner end of the slave cylinder is provided with the master cylinder piston, forming a high-pressure chamber and a gas chamber inside the master cylinder. One end of the master cylinder is provided with a high-pressure oil inlet communicating with the high-pressure chamber, and the other end is provided with a gas hole communicating with the gas chamber. The piston rod is coaxially placed with the slave cylinder, and the inner end of the piston rod is provided with the slave cylinder piston, forming an opening mold chamber and a closing mold chamber inside the slave cylinder. The outer end of the piston rod is respectively provided with a first oil passage communicating with the opening mold chamber and a second oil passage communicating with the closing mold chamber. This invention inputs hydraulic oil into the opening mold chamber in the slave cylinder through the first oil passage, which drives the slave cylinder to move upward to achieve mold opening, so that hydraulic oil does not need to be input into the gas chamber of the master cylinder, effectively avoiding leakage and improving the working environment.

Description

Technical Field

[0001] This invention relates to the field of injection molding, and specifically to a mother-daughter cylinder with a pressure-holding function. Background Technology

[0002] Injection molding machines are well known in the field and are used to make plastic products from thermoplastic or thermosetting plastics using plastic molds. The advantages of injection molding machines are that they can mold plastic products with complex shapes, precise dimensions, or inserts in one step, with high productivity and easy automation.

[0003] As disclosed in prior art 202110554670.8, a high-efficiency master-slave cylinder and its hydraulic control system include a master cylinder body, a slave cylinder body, and a piston rod arranged sequentially from the outside to the inside. The bottom of the master cylinder body is provided with a mold opening oil inlet. The slave cylinder body is slidably disposed in the master cylinder body, with its lower end extending out of the cylinder body, so that the inside of the master cylinder body forms a mold closing cavity and a mold opening cavity. When opening the mold, hydraulic oil needs to be input into the mold opening cavity through the mold opening oil inlet, thereby driving the slave cylinder body to move upward and realize mold opening. However, since the lower cover of the master cylinder body is movably connected to the slave cylinder body, when hydraulic oil is input into the mold opening cavity through the mold opening oil inlet, under high pressure, the hydraulic oil in the mold opening cavity is prone to leakage from the lower cover connection, which not only wastes hydraulic oil but also affects the working environment. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a female cylinder with a pressure-holding function.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a mother cylinder with a pressure-holding function, comprising a mother cylinder, a daughter cylinder disposed inside the mother cylinder and whose outer end can extend out of the mother cylinder, and a piston rod disposed inside the mother cylinder and whose inner end extends into the daughter cylinder;

[0006] The sub-cylinder and the mother cylinder are placed coaxially. The mother cylinder piston is provided at the inner end of the sub-cylinder, forming a high-pressure chamber and a gas chamber inside the mother cylinder. One end of the mother cylinder is provided with a high-pressure oil inlet communicating with the high-pressure chamber, and the other end is provided with a gas hole communicating with the gas chamber. The high-pressure oil inlet is connected to a full oil valve.

[0007] The piston rod is placed coaxially with the sub-cylinder, and the inner end of the piston rod is provided with the sub-cylinder piston, forming an opening cavity and a closing cavity inside the sub-cylinder; the outer end of the piston rod is respectively provided with a first oil passage communicating with the opening cavity and a second oil passage communicating with the closing cavity.

[0008] Preferably, the mother cylinder includes a mother cylinder body, a mother cylinder upper cover disposed at one end of the mother cylinder body, and a mother cylinder lower cover disposed at the other end of the mother cylinder body; the high-pressure oil inlet is disposed on the mother cylinder upper cover, and the air hole is disposed on the mother cylinder lower cover; the daughter cylinder extends out of the mother cylinder through the mother cylinder lower cover.

[0009] Preferably, the mother cylinder cover is also provided with a differential oil inlet.

[0010] Preferably, multiple evenly placed connecting rods are provided around the mother cylinder body between the upper cover and the lower cover of the mother cylinder, so that the upper cover and the lower cover of the mother cylinder are tightly connected to the two ends of the mother cylinder body respectively.

[0011] Preferably, a first sealing ring is provided at the connection between the upper cover of the mother cylinder and the body of the mother cylinder, the connection between the lower cover of the mother cylinder and the body of the mother cylinder, and the connection between the body of the mother cylinder and the piston of the mother cylinder.

[0012] Preferably, the bottom of the lower cover of the mother cylinder is further provided with a guide positioning ring sleeved on the daughter cylinder; the guide positioning ring is connected to the lower cover of the mother cylinder by bolts, and a self-lubricating bushing is provided at the connection with the daughter cylinder; a gap is provided between the lower cover of the mother cylinder and the daughter cylinder.

[0013] Preferably, the sub-cylinder includes a sub-cylinder body, a sub-cylinder inner cover disposed at the inner end of the sub-cylinder body, and a sub-cylinder outer cover disposed at the outer end of the sub-cylinder body; the end face of the sub-cylinder inner cover is flush with the end face of the sub-cylinder piston; the diameter of the sub-cylinder outer cover is larger than the diameter of the sub-cylinder body, and the portion of the outer cover protruding from the sub-cylinder body is provided with multiple mounting holes.

[0014] Preferably, a second sealing ring is provided at the connection between the inner cover of the sub-cylinder and the cylinder body, the connection between the outer cover of the sub-cylinder and the cylinder body, and the connection between the cylinder body and the piston of the sub-cylinder.

[0015] Preferably, the outer end of the piston rod is threadedly connected to the upper cover of the mother cylinder.

[0016] Preferably, a third sealing ring is provided at the connection between the piston rod and the inner cover of the sub-cylinder, and at the connection between the piston rod and the upper cover of the mother cylinder.

[0017] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0018] This invention inputs hydraulic oil into the mold opening cavity of the sub-cylinder through the first oil passage, which drives the sub-cylinder to move upward to open the mold. This eliminates the need to input hydraulic oil into the air cavity of the mother cylinder, effectively avoiding leakage and improving the working environment. Attached Figure Description

[0019] The technical solution of the present invention will be further described below with reference to the accompanying drawings:

[0020] Appendix Figure 1 This is a schematic diagram of the structure of the mother-daughter cylinder with pressure-holding function described in this invention;

[0021] Appendix Figure 2 This is a cross-sectional view of the pressure-holding cylinder with female-female function described in this invention;

[0022] Appendix Figure 3 This is a longitudinal sectional view of the pressure-holding cylinder described in this invention.

[0023] The components are as follows: 1. Mother cylinder; 10. Connecting rod; 11. Mother cylinder piston; 12. High-pressure chamber; 13. Air chamber; 14. High-pressure oil inlet; 15. Air hole; 16. Mother cylinder body; 17. Mother cylinder upper cover; 18. Mother cylinder lower cover; 19. Differential oil inlet; 2. Daughter cylinder; 20. Mounting hole; 21. Daughter cylinder piston; 22. Mold opening cavity; 23. Mold closing cavity; 24. First oil passage; 25. Second oil passage; 26. Daughter cylinder body; 27. Daughter cylinder inner cover; 28. Daughter cylinder outer cover; 3. Piston rod; 4. Full oil valve; 5. Guide positioning ring; 6. Self-lubricating bushing. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] Appendix Figure 1-3 The pressure-holding cylinder of the present invention includes a mother cylinder 1, a daughter cylinder 2 which is vertically arranged in the mother cylinder 1 and whose lower end can extend out of the bottom of the mother cylinder 1, and a piston rod 3 which is vertically arranged in the mother cylinder 1 and whose lower end extends into the daughter cylinder 2.

[0026] The sub-cylinder 2 is placed coaxially with the mother cylinder 1. The upper end of the sub-cylinder 2 is provided with the mother cylinder piston 11, forming a high-pressure chamber 12 and an air chamber 13 inside the mother cylinder 1. The high-pressure chamber 12 is located above the air chamber 13. The upper end of the mother cylinder 1 is provided with a high-pressure oil inlet 14 communicating with the high-pressure chamber 12, and the lower end is provided with an air hole 15 communicating with the air chamber 13. The high-pressure oil inlet 14 is connected to the full oil valve 4.

[0027] The piston rod 3 is placed coaxially with the sub-cylinder 2. The lower end of the piston rod 3 is provided with a sub-cylinder piston 21, which forms an opening mold cavity 22 and a closing mold cavity 23 inside the sub-cylinder 2. The opening mold cavity 22 is located above the closing mold cavity 23. The upper end of the piston rod 3 is provided with a first oil passage 24 communicating with the opening mold cavity 22 and a second oil passage 25 communicating with the closing mold cavity 23.

[0028] During mold closing: First, hydraulic oil is input into the mold closing cavity 23 through the second oil circuit 25 to drive the sub-cylinder 2 to descend and realize mold closing; at the same time, the full oil valve 4 is opened and high-pressure oil is input into the high-pressure cavity 12 through the high-pressure oil inlet 14 to complete the mold locking action and improve the injection molding quality;

[0029] When the mold is opened: hydraulic oil is input into the mold opening cavity 22 through the first oil circuit 24, driving the sub-cylinder 2 to lift the upper mold plate. At this time, the oil in the high pressure cavity 12 and the mold closing cavity 23 flows back to the oil tank, realizing the mold opening. Since hydraulic oil does not need to be input into the air cavity 13 of the mother cylinder 1, leakage is effectively avoided and the working environment is improved.

[0030] Furthermore, the mother cylinder 1 includes a mother cylinder body 16, a mother cylinder upper cover 17 disposed at the upper end of the mother cylinder body 16, and a mother cylinder lower cover 18 disposed at the lower end of the mother cylinder body 16; the high-pressure oil inlet 14 is disposed on the mother cylinder upper cover 17, and the air hole 15 is disposed on the mother cylinder lower cover 18; the daughter cylinder 2 extends out of the mother cylinder 2 through the mother cylinder lower cover 18; the present invention divides the mother cylinder into three parts: the mother cylinder body 16, the mother cylinder upper cover 17, and the mother cylinder lower cover 18, which facilitates processing and assembly.

[0031] Furthermore, the upper cover 17 of the mother cylinder is also provided with a differential oil inlet 19; when the mold is closed, the hydraulic oil discharged from the first oil circuit 24 can be input into the high pressure chamber 12 through the differential oil inlet 19, which can not only improve the mold closing speed, but also output a large force, which can meet the needs of large load occasions.

[0032] Furthermore, multiple evenly placed connecting rods 10 are provided around the cylinder body 16 between the upper cover 17 and the lower cover 18 of the mother cylinder; the present invention can effectively connect the upper cover 17 and the lower cover 18 of the mother cylinder to the two ends of the cylinder body 16 respectively through multiple connecting rods 10, thereby improving the connection strength.

[0033] Furthermore, a first sealing ring is provided at the connection between the upper cover 17 and the body 16 of the mother cylinder, the connection between the lower cover 18 and the body 16 of the mother cylinder, and the connection between the body 16 and the piston 11 of the mother cylinder, which plays a sealing role in the connection parts of the mother cylinder.

[0034] Furthermore, a guide positioning ring 5 is also provided at the bottom of the lower cover 18 of the mother cylinder, which is sleeved on the daughter cylinder 2; the guide positioning ring 5 is connected to the lower cover 18 of the mother cylinder by bolts, and a self-lubricating bushing 6 is provided at the connection between the guide positioning ring 5 and the daughter cylinder 2; a gap is provided between the lower cover 18 of the mother cylinder and the daughter cylinder 2; by providing the guide positioning ring 5, the present invention can guide the daughter cylinder 2, and at the same time, the self-lubricating bushing 6 provided at the connection between the guide positioning ring 5 and the daughter cylinder 2 can provide lubrication, which can effectively prevent the daughter cylinder body 26 from contacting the lower cover 18 of the mother cylinder, reduce wear, and improve service life.

[0035] Furthermore, the sub-cylinder 2 includes a sub-cylinder body 26, a sub-cylinder inner cover 27 disposed at the inner end of the sub-cylinder body 26, and a sub-cylinder outer cover 28 disposed at the outer end of the sub-cylinder body 26; the end face of the sub-cylinder inner cover 27 is flush with the end face of the sub-cylinder piston 21; the diameter of the sub-cylinder outer cover 28 is larger than the diameter of the sub-cylinder body 26, and the part protruding from the sub-cylinder body 26 is provided with multiple mounting holes 20; the present invention divides the sub-cylinder into three parts: the sub-cylinder body, the sub-cylinder inner cover 27, and the sub-cylinder outer cover 28, which facilitates processing and assembly. The end face of the sub-cylinder inner cover 27 is flush with the end face of the sub-cylinder piston 21, which can increase the lifting height of the sub-cylinder without changing the height of the main cylinder, and the sub-cylinder outer cover 28 is provided with multiple mounting holes 20 for easy installation.

[0036] Furthermore, a second sealing ring is provided at the connection between the inner cover 27 and the cylinder body 26, the connection between the outer cover 28 and the cylinder body 26, and the connection between the cylinder body 26 and the piston 21, which serves to seal the connection parts of the cylinder.

[0037] Furthermore, the upper end of the piston rod 3 is threadedly connected to the upper cover 17 of the mother cylinder for easy installation.

[0038] Furthermore, a third sealing ring is provided at the connection between the piston rod 3 and the inner cover 27 of the sub-cylinder, and at the connection between the piston rod 3 and the upper cover 17 of the mother cylinder, which serves to seal the connection of the piston rod 3.

[0039] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. All technical solutions formed by equivalent transformations or substitutions fall within the scope of protection of the present invention.

Claims

1. A mother-daughter cylinder with pressure-holding function, characterized in that: It includes a mother cylinder, a daughter cylinder disposed inside the mother cylinder and whose outer end can extend out of the mother cylinder, and a piston rod disposed inside the mother cylinder and whose inner end extends into the daughter cylinder; The sub-cylinder and the mother cylinder are placed coaxially. The mother cylinder piston is provided at the inner end of the sub-cylinder, forming a high-pressure chamber and a gas chamber inside the mother cylinder. One end of the mother cylinder is provided with a high-pressure oil inlet communicating with the high-pressure chamber, and the other end is provided with a gas hole communicating with the gas chamber. The high-pressure oil inlet is connected to a full oil valve. The piston rod is placed coaxially with the sub-cylinder, and the inner end of the piston rod is provided with the sub-cylinder piston, forming an opening cavity and a closing cavity inside the sub-cylinder; the outer end of the piston rod is respectively provided with a first oil passage communicating with the opening cavity and a second oil passage communicating with the closing cavity. The mother cylinder includes a mother cylinder body, a mother cylinder upper cover located at one end of the mother cylinder body, and a mother cylinder lower cover located at the other end of the mother cylinder body; the high-pressure oil inlet is located on the mother cylinder upper cover, while the air vent is located on the mother cylinder lower cover; the daughter cylinder extends out of the mother cylinder through the mother cylinder lower cover. The bottom of the lower cover of the mother cylinder is also provided with a guide positioning ring that is sleeved on the daughter cylinder; the guide positioning ring is connected to the lower cover of the mother cylinder by bolts, and a self-lubricating bushing is provided at the connection with the daughter cylinder; a gap is provided between the lower cover of the mother cylinder and the daughter cylinder.

2. The female cylinder with pressure-holding function according to claim 1, characterized in that: The mother cylinder cover is also equipped with a differential oil inlet.

3. The female cylinder with pressure-holding function according to claim 2, characterized in that: Multiple evenly placed connecting rods are provided around the mother cylinder body between the upper cover and the lower cover of the mother cylinder, so that the upper cover and the lower cover of the mother cylinder are tightly connected to the two ends of the mother cylinder body respectively.

4. The female cylinder with pressure-holding function according to claim 3, characterized in that: A first sealing ring is provided at the connection between the upper cover of the mother cylinder and the body of the mother cylinder, the connection between the lower cover of the mother cylinder and the body of the mother cylinder, and the connection between the body of the mother cylinder and the piston of the mother cylinder.

5. The female cylinder with pressure-holding function according to any one of claims 1-4, characterized in that: The sub-cylinder includes a sub-cylinder body, an inner sub-cylinder cover disposed at the inner end of the sub-cylinder body, and an outer sub-cylinder cover disposed at the outer end of the sub-cylinder body; the end face of the inner sub-cylinder cover is flush with the end face of the sub-cylinder piston; the diameter of the outer sub-cylinder cover is larger than the diameter of the sub-cylinder body, and the portion of the outer sub-cylinder cover protruding from the sub-cylinder body is provided with multiple mounting holes.

6. The female cylinder with pressure-holding function according to claim 5, characterized in that: A second sealing ring is provided at the connection between the inner cover of the sub-cylinder and the cylinder body, the connection between the outer cover of the sub-cylinder and the cylinder body, and the connection between the cylinder body and the piston of the sub-cylinder.

7. The female cylinder with pressure-holding function according to claim 6, characterized in that: The outer end of the piston rod is threadedly connected to the top cover of the mother cylinder.

8. The female cylinder with pressure-holding function according to claim 7, characterized in that: A third sealing ring is provided at the connection between the piston rod and the inner cover of the sub-cylinder, and at the connection between the piston rod and the upper cover of the mother cylinder.

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