Method for manufacturing integrated hydraulic accumulator bladder

Abstract

A method for manufacturing a hydraulic accumulator bladder includes the following steps: bonding a rubber sheet to the gas-filled air bladder to form a bladder blank; placing the bladder blank in a vulcanization device for vulcanization to form an initial bladder product; and releasing the gas in the gas-filled air bladder of the initial bladder product, taking the air bladder out, and naturally cooling the initial bladder product to a room temperature to form a finished bladder product. The bladder manufactured by the manufacturing method is integrally formed by one-step vulcanization, and has the advantages of uniform wall thickness, smooth inner and outer surfaces, long fatigue lifetime, a simplified process, high quality and good stability.

Claims

1. A method for manufacturing a hydraulic accumulator bladder, comprising: a. preparation of a sizing material; mixing a nitrile butadiene rubber, a polyvinyl chloride plastic, a zinc oxide, a stearic acid, a paraffin and an antioxidant in an internal mixer under a mixing temperature of 80 C. for 6 minutes until a Mooney viscosity of the nitrile butadiene rubber is between 55 and 60; adding a N220 carbon black and a N774 carbon black into the mixer under a mixing temperature of 80 C. for 6 minutes; adding the N220 carbon black, the N774 carbon black and a DOA plasticizer into the mixer and mixing under a temperature of 80 C. for 6 minutes to obtain a master batch; filtering the master batch in a rubber filter, placing it in an open mill, adding a S-80 vulcanizing agent and a DM vulcanizing agent and mixing to obtain a rubber compound; blending the rubber compound on a hot mill; calendering the blended rubber compound in a calender, extrudering the calendered rubber compound in an extruder, discharging the extrudered rubber compound and cooling to obtain the sizing material; b. preheating the sizing material in a rubber baking room of 60 C. to 70 C. for 3 to 8 hours; and c. winding the sizing material around a gas-filled air bladder to form a bladder blank. d. placing the bladder blank in a vulcanization device for vulcanization to form an initial bladder product; and e. releasing the gas in the gas-filled air bladder of the initial bladder product, taking the air bladder out, and cooling the initial bladder product to a room temperature to obtain the hydraulic accumulator bladder.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram showing a structure of an accumulator in the prior art.

(2) In FIG. 1, 1: accumulator; 2: bladder; 3: oil valve; and 4: gas valve.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(3) The present invention will be described in detail with reference to examples.

(4) The present invention provides a method for manufacturing a hydraulic accumulator bladder, which includes: bonding a rubber sheet to the gas-filled air bladder to form a bladder blank, more specifically, preheating the rubber sheet in a rubber baking room of 60 DEG C. to 70 DEG C. for 3 to 8 hours, preferably, 4 hours, and then winding the rubber sheet around the gas-filled air bladder for multiple layers to form an initial bladder product.

(5) The method for manufacturing the hydraulic accumulator bladder further includes: placing the bladder blank in a vulcanization device for vulcanization to form an initial bladder product.

(6) The method for manufacturing the hydraulic accumulator bladder further includes: releasing the gas in the gas-filled air bladder of the initial bladder product, taking the air bladder out, and naturally cooling the vulcanized initial product to a room temperature to form a finished bladder product.

(7) The present invention provides a sizing material for a hydraulic accumulator bladder, which is prepared from at least the following raw materials in parts by weight: 50 to 90 parts by weight of nitrile butadiene rubber, 10 to 50 parts by weight of polyvinyl chloride plastic, 3 to 5 parts by weight of zinc oxide, 1 to 1.5 parts by weight of stearic acid, 0.5 to 1 part by weight of paraffin, 2.5 to 3 parts by weight of an antioxidant, 40 to 42.5 parts by weight of N220 carbon black, 7.5 to 10 parts by weight of N774 carbon black, 20 to 22 parts by weight of a plasticizer, 1.5 to 1.8 parts by weight of a S-80 vulcanizing agent, and 0.85 to 1.2 parts by weight of a DM vulcanizing agent.

EXAMPLE 1

(8) An example 1 of the present invention provides a sizing material for a hydraulic accumulator bladder, which is prepared from at least the following raw materials in parts by weight: 70 parts by weight of nitrile butadiene rubber, 30 parts by weight of polyvinyl chloride plastic, 3 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1 part by weight of paraffin, 2.5 parts by weight of an antioxidant, 40 parts by weight of N220 carbon black, 7.5 parts by weight of N774 carbon black, 20 parts by weight of a plasticizer, 1.5 parts by weight of a S-80 vulcanizing agent, and 0.85 part by weight of a DM vulcanizing agent.

(9) The sizing material for the hydraulic accumulator bladder provided by the example 1 of the present invention is prepared by adopting the following steps:

(10) step 1, mixing the nitrile butadiene rubber, the polyvinyl chloride plastic, the zinc oxide, the stearic acid, the paraffin and the 4010NA antioxidant which are weighed in parts by weight in an internal mixer, where the mixing temperature is controlled at 80 DEG C., the time is about 6 min and the nitrile butadiene rubber is processed until the Mooney viscosity is preferably between 55 and 60;

(11) step 2, adding of the N220 carbon black weighed in parts by weight and of the N774 carbon black weighed in parts by weight in the above sizing material for mixing, where the mixing temperature is controlled at 80 DEG C. and the time is about 6 min;

(12) step 3, adding of the N220 carbon black weighed in parts by weight, of the N774 carbon black weighed in parts by weight and the DOA plasticizer weighed in parts by weight for mixing to obtain a master batch, where the mixing temperature is controlled at 80 DEG C. and the time is about 4 min;

(13) step 4, filtering the master batch in a rubber filter, then placing it in an open mill, and then adding the S-80 vulcanizing agent and the DM vulcanizing agent for mixing to obtain a rubber compound;

(14) step 5, blending the rubber compound on a hot mill for improving the mixing uniformity of the sizing material and further increasing the plasticity; and

(15) step 6, placing the rubber compound in a calender to calender a rubber sheet, then placing it in an extruder to extrude a rubber sheet, and then discharging the rubber sheet and cooling it.

EXAMPLE 2

(16) An example 2 of the present invention provides a sizing material for a hydraulic accumulator bladder, which is prepared from at least the following raw materials in parts by weight: 90 parts by weight of nitrile butadiene rubber, 50 parts by weight of polyvinyl chloride plastic, 5 parts by weight of zinc oxide, 1.5 parts by weight of stearic acid, 0.5 part by weight of paraffin, 3 parts by weight of an antioxidant, 40 parts by weight of N220 carbon black, 7.5 parts by weight of N774 carbon black, 22 parts by weight of a plasticizer, 1.8 parts by weight of a S-80 vulcanizing agent, and 1.2 parts by weight of a DM vulcanizing agent.

(17) The sizing material for the hydraulic accumulator bladder provided by the example 2 of the present invention is prepared by adopting the following steps:

(18) step 1, mixing the nitrile butadiene rubber, the polyvinyl chloride plastic, the zinc oxide, the stearic acid, the paraffin and the 4010NA antioxidant which are weighed in parts by weight in an internal mixer, where the mixing temperature is controlled at 83 DEG C., the time is about 8 min and the nitrile butadiene rubber is processed until the Mooney viscosity is preferably between 55 and 60;

(19) step 2, adding of the N220 carbon black weighed in parts by weight and of the N774 carbon black weighed in parts by weight in the above sizing material for mixing, where the mixing temperature is controlled at 83 DEG C. and the time is about 8 min;

(20) step 3, adding of the N220 carbon black weighed in parts by weight, of the N774 carbon black weighed in parts by weight and the DOA plasticizer weighed in parts by weight for mixing to obtain a master batch, where the mixing temperature is controlled at 83 DEG C. and the time is about 4 min;

(21) step 4, filtering the master batch in a rubber filter, then placing it in an open mill, and then adding the S-80 vulcanizing agent and the DM vulcanizing agent which are weighed in parts by weight for mixing to obtain a rubber compound;

(22) step 5, blending the rubber compound on a hot mill for improving the mixing uniformity of the sizing material and further increasing the plasticity; and

(23) step 6, placing the rubber compound in a calender to calender a rubber sheet, then placing it in an extruder to extrude a rubber sheet, and then discharging the rubber sheet and cooling it.

EXAMPLE 3

(24) An example 3 of the present invention provides a sizing material for a hydraulic accumulator bladder, which is prepared from at least the following raw materials in parts by weight: 90 parts by weight of nitrile butadiene rubber, 50 parts by weight of polyvinyl chloride plastic, 5 parts by weight of zinc oxide, 1.5 parts by weight of stearic acid, 0.5 part by weight of paraffin, 3 parts by weight of an antioxidant, 40 parts by weight of N220 carbon black, 7.5 parts by weight of N774 carbon black, 22 parts by weight of a plasticizer, 1.8 parts by weight of a S-80 vulcanizing agent, and 1.2 parts by weight of a DM vulcanizing agent.

(25) The sizing material for the hydraulic accumulator bladder provided by the example 3 of the present invention is prepared by adopting the following steps:

(26) step 1, mixing the nitrile butadiene rubber, the polyvinyl chloride plastic, the zinc oxide, the stearic acid, the paraffin and the 4010NA antioxidant which are weighed in parts by weight in an internal mixer, where the mixing temperature is controlled at 77 DEG C., the time is about 8 min and the nitrile butadiene rubber is processed until the Mooney viscosity is preferably between 55 and 60;

(27) step 2, adding of the N220 carbon black weighed in parts by weight and of the N774 carbon black weighed in parts by weight in the above sizing material for mixing, where the mixing temperature is controlled at 77 DEG C. and the time is about 8 min;

(28) step 3, adding of the N220 carbon black weighed in parts by weight, of the N774 carbon black weighed in parts by weight and the DOA plasticizer weighed in parts by weight for mixing to obtain a master batch, where the mixing temperature is controlled at 77 DEG C. and the time is about 4 min;

(29) step 4, filtering the master batch in a rubber filter, then placing it in an open mill, and then adding the S-80 vulcanizing agent and the DM vulcanizing agent which are weighed in parts by weight for mixing to obtain a rubber compound;

(30) step 5, blending the rubber compound on a hot mill for improving the mixing uniformity of the sizing material and further increasing the plasticity; and

(31) step 6, placing the rubber compound in a calender to calender a rubber sheet, then placing it in an extruder to extrude a rubber sheet, and then discharging the rubber sheet and cooling it.

EXAMPLE 4

(32) An example 4 of the present invention provides a sizing material for a hydraulic accumulator bladder, which is prepared from at least the following raw materials in parts by weight: 50 parts by weight of nitrile butadiene rubber, 10 parts by weight of polyvinyl chloride plastic, 3 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1 part by weight of paraffin, 3 parts by weight of an antioxidant, 42.5 parts by weight of N220 carbon black, 7.5 parts by weight of N774 carbon black, 22 parts by weight of a plasticizer, 1.5 parts by weight of a S-80 vulcanizing agent, and 0.85 part by weight of a DM vulcanizing agent.

(33) The sizing material for the hydraulic accumulator bladder provided by the example 4 of the present invention is prepared by adopting the following steps:

(34) step 1, mixing the nitrile butadiene rubber, the polyvinyl chloride plastic, the zinc oxide, the stearic acid, the paraffin and the 4010NA antioxidant which are weighed in parts by weight in an internal mixer, where the mixing temperature is controlled at 85 DEG C., the time is about 7 min and the nitrile butadiene rubber is processed until the Mooney viscosity is preferably between 55 and 60;

(35) step 2, adding of the N220 carbon black weighed in parts by weight and of the N774 carbon black weighed in parts by weight in the above sizing material for mixing, where the mixing temperature is controlled at 85 DEG C. and the time is about 7 min;

(36) step 3, adding of the N220 carbon black weighed in parts by weight, of the N774 carbon black weighed in parts by weight and the DOA plasticizer for mixing to obtain a master batch, where the mixing temperature is controlled at 85 DEG C. and the time is about 6 min;

(37) step 4, filtering the master batch in a rubber filter, then placing it in an open mill, and then adding the S-80 vulcanizing agent and the DM vulcanizing agent which are weighed in parts by weight for mixing to obtain a rubber compound;

(38) step 5, blending the rubber compound on a hot mill for improving the mixing uniformity of the sizing material and further increasing the plasticity; and

(39) step 6, placing the rubber compound in a calender to calender a rubber sheet, then placing it in an extruder to extrude a rubber sheet, and then discharging the rubber sheet and cooling it.

(40) By testing, technical performance indicators of the bladder manufactured by using the sizing material provided by the present invention are shown in Table 1.

(41) TABLE-US-00001 TABLE 1 No. Item Detection result 1 Hardness (Shore) 36-38 2 Tensile strength 18 Mpa 3 Elongation at break 500% 4 Permanent deformation rate under 15% compression 70 DEG C./24 h 5 Hot-air aging 70 DEG C/120 h Change rate of tensile strength 15% Change rate of elongation at break 15% Change rate of hardness (Shore) 3% 6 High-temperature aging 70 DEG C./120 h Change rate of tensile strength 15% Change rate of elongation at break 15% 7 Tear strength (kN/m) 115 8 Change rate of oil-resistant volume 30% 70 DEG C./120 h, No. 25 hydraulic oil 9 Detergent soaking resistance Change rates after 70 DEG C./24 h, 1%-concentration detergent soaking all 30% Change rate of tensile strength no hardening and Change rate of elongation at break cracks occur 10 Low-temperature brittleness temperature 65/DEG C. resistance/DEG C.

(42) A rubber-plastic alloy bladder of the present invention adopts nitrile butadiene rubber as main base material, and a part of polyvinyl chloride is added as an effective material for modification. From a research perspective of a high-molecular material, a double bond on a long chain of the nitrile butadiene rubber is terminated by a polyvinyl chloride (PVC) macromolecule, such that the sizing material for the hydraulic accumulator bladder provided by the present invention has a highly saturated elastomer, good oil resistance (good resistance to fuel oil, lubricating oil and aromatic series solvents), and good heat resistance, excellent chemical corrosion resistance (good resistance to Freon, acid and alkali), excellent ozone resistance, higher anti-compression set performance because of its highly saturated structure, and also has characteristics of high strength, high tear resistance, excellent wear resistance and the like.

(43) The sizing material for the hydraulic accumulator bladder provided by the present invention not only solves the technical problems of short service life and the like in the prior art, but also makes the content of polycyclic aromatic hydrocarbons (PAHs) in the bladder fully meet the European Union environmental protection requirements. The content of the PAHs is analyzed and detected by adopting a GC-MS method, and its result does not exceed 0.5 mg/kg, which fully meets the European Union environmental protection requirements. High elasticity and tightness of the sizing material in thick oil and concentrated solvents are not changed for a long time. The sizing material is hard to age in long-term work under a high-temperature and high-pressure environment, maintains high elasticity of the bladder, and prolongs its service life.

(44) Basic principles, main features, and advantages of the present invention have been shown and described above. It should be understood by those skilled in the art that the present invention is not limited by the foregoing examples. The foregoing examples and the description describe only the principles of the present invention, and there will be various changes and improvements in the present invention without departing from the spirit and scope of the present invention. These changes and improvements are within a protective scope of the present invention. The protective scope of the present invention is defined by the appended claims and their equivalents.

INDUSTRIAL APPLICABILITY

(45) Compared with the prior art, the bladder manufactured by the method for manufacturing the hydraulic accumulator bladder provided in this disclosure is integrally formed by one-step vulcanization, and has the advantages of uniform wall thickness, smooth inner and outer surfaces, long fatigue lifetime, a simplified process, high product quality, and good stability. The bladder is excellent in gas sealing performance, may effectively prevent the gas in a bladder body from leaking, and can eliminate a peak-valley value of the pressure fluctuation. The bladder is very high in industrial applicability and operability, and can be industrially realized.