JP3419102B2 - Method for producing oil-impregnated polymer molded article and product obtained by this method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin molded product containing a lubricating oil, a so-called oil-impregnated polymer molded product, and more particularly, to a rolling bearing for steel equipment where a grease lubrication system cannot be adopted, and a twisting machine that receives centrifugal force at high speed The present invention relates to a method of manufacturing an oil-impregnated polymer molded product used for a rolling bearing used in a harsh environment such as, and other rolling bearings, linear motion rolling bearings, sliding bearings, ball screws, and the like.

[0002]

2. Description of the Related Art Generally, a resin material of an oil-containing polymer known as a synthetic oil-containing resin includes a polyolefin resin which easily absorbs a lubricating oil, a thermosetting resin such as a phenol resin or a polyurethane resin, or a mixture thereof. Has been used. For example, in Japanese Examined Patent Publication No. 63-23239,
A lubricating composition for a bearing using a polyethylene resin is shown. This product is manufactured by a method in which an oil-containing composition obtained by mixing a polyethylene resin and a lubricating grease is applied or enclosed in a bearing or the like that is a member to be lubricated, and the temperature is raised and then cooled to solidify the resin.

[0003]

However, the above-mentioned conventional method for producing an oil-impregnated polymer product in which an oil-impregnated composition is applied to or sealed in a lubricated member such as a bearing, heated, and then solidified by cooling has poor productivity. There is a problem that it cannot be mass-produced. Therefore, the present invention has been made by paying attention to such a conventional problem, and molds an oil-impregnated polymer molding material into a predetermined product shape using a plunger type injection molding machine or a transfer molding machine. It is an object of the present invention to provide a method for producing such an oil-impregnated polymer molded article having high productivity.

[0004]

A method for producing an oil-impregnated polymer molded article according to the present invention , which achieves the above object, comprises:
The content of lubricating oil is 20 to 80% by weight and powder or
Is a paste-like oil-containing polymer molding material,
The material is supplied to a concave cylindrical portion, and the heated material is pressed by a plunger fitted into the cylindrical portion to flow into the concave molding portion of the mold. Also,
The sealing member for a linear guide device according to claim 2 according to
From an oil-impregnated polymer molded product obtained by the method according to claim 1.
It is characterized by Further, claim 3 according to the present invention
The ball bearing cage according to claim 1 was obtained by the method according to claim 1.
It is characterized by comprising an oil-impregnated polymer molded product. further,
According to a fourth aspect of the present invention, there is provided a rolling bearing including an outer ring and an inner ring.
A rolling element held by a cage is arranged between the outer ring and
Obtained by the method according to claim 1, in a space between the inner ring and the inner ring.
The self-lubricating filler consisting of the oil-impregnated polymer molded product
It is characterized by being filled and sealed. Furthermore, the book
A self-lubricating seal portion for a ball screw according to claim 5 of the present invention.
The material is an oil-containing polymer molding obtained by the method according to claim 1.
It is characterized by consisting of goods. Furthermore, the contract according to the present invention
The direct acting slide bearing of Requirement 6 is a plain bearing made of synthetic resin.
A body and an oil-impregnated polymer molding material that surrounds the body
The self-lubricating composition molded product is integrated to obtain the self-lubricating property.
A molded article of the composition is an oil-containing foam obtained by the method according to claim 1.
It is a Lima molded product.

[0005]

In the present invention, the step of measuring the oil-containing polymer molding material is performed by supplying the material to the cylindrical portion. In addition, the injection of the resin heated and melted in the cylindrical part,
Use a plunger (piston).

Even when an oil-containing polymer molding material containing lubricating oil is to be molded by a general screw injection molding machine, as will be described later, the clearance between the screw and the cylinder is too large and the check portion has a length in the axial direction. Since the length is short, the airtightness is not sufficient, and therefore the metering and injection processes do not work well. On the other hand, in the plunger (piston) type injection molding machine, the clearance with the cylindrical heating portion is small, and the resin can be measured and injected smoothly, so that stable molding can be performed. In addition, since the transfer molding machine also injects the molten resin in the pot-shaped heating section with the plunger, similarly, the resin can be smoothly measured and the injection process can be performed, and stable molding can be performed. Hereinafter, the present invention will be described in more detail.

As the resin component of the oil-containing polymer molding material used in the present invention, a polyolefin resin such as polypropylene resin or poly-4-methylpentene-1 resin, or a thermosetting resin such as phenol resin or urethane resin can be used. Is. Further, glass fibers, carbon fibers, whiskers, Kevlar fibers, etc. may be appropriately added to these resin compositions as a reinforcing material.

Examples of the lubricating oil of the oil-containing polymer molding material used in the present invention include mineral oil, poly α-olefin oil, alkyl polyphenyl ether oil, ester oil, diester oil, alkyl naphthalene oil and the like. The oil-containing polymer molding material used in the present invention is obtained by adding the lubricating oil to the resin component powder, heating and cooling the mixture to obtain a jelly-like composition, and crushing it with a mixer or the like, and further adding the resin component powder. It is preferably kneaded into a powder or paste.

The oil-impregnated polymer molded article is manufactured by supplying the oil-impregnated polymer molding material to an injection molding machine or a transfer molding machine equipped with a mold having a cavity of a predetermined product shape and injection molding the same. Thus, the oil-containing polymer molding material of the present invention is in the form of powder or paste containing lubricating oil as described above, and when a shearing force is applied, oil content is separated. Therefore, with an ordinary in-line screw type injection molding machine, the measurement and injection of the material are unstable, and it is difficult to obtain a product of stable quality.

Therefore, in the method for producing an oil-impregnated polymer molded product of the present invention, a plunger type injection molding machine or a transfer molding machine is used instead of the screw type injection molding machine which is generally used. Stable quality is achieved by mounting a predetermined mold on these molding machines, heating the oil-impregnated polymer molding material above the melting point of the component resin, injecting or transferring the melted product into the mold, and then taking out after cooling. Can be molded with high productivity. This enabled stable and highly productive molding.

FIG. 1 shows an outline of a method of manufacturing an oil-impregnated polymer molded product (for example, a cylindrical plain bearing) when a plunger type injection molding machine is used. Oil-impregnated polymer molding material 1
Is supplied from the hopper 2 into the concave cylindrical portion 4 having a constant volume in the cylindrical heating portion 3, and is heated to a predetermined temperature by the heater 5. The molten oil-containing polymer molding material 1 in a heated and plasticized state is pressed by a convex cylindrical plunger 6 that fits in the cylindrical portion 4 and moves in the axial direction, and enters the mold 8 from the nozzle 7. Is ejected. Then, it is press-fitted into the molding portion (cavity) 12 from the gate 11 via the spool 9 and the runner 10. The oil-containing polymer molding material 1 in a molten state, which is press-fitted into the molding portion 12, is cooled and solidified in the mold. After that, the mold 8 is moved to the parting line P. Open with L and take out the solidified product in the molding part 12. By using the plunger 6 in this way, good sealing property in the molten resin injection process can be secured, and sufficient pressure can be applied to the molten resin of the oil-containing polymer molding material, and as a result, a stable product can be manufactured. It becomes possible to do.

FIG. 2 shows an example of manufacturing an oil-impregnated polymer molded product similar to the above using a transfer molding machine. The oil-impregnated polymer molding material 1 is supplied into the pot-shaped heating portion 16 mounted on the mold 15. In this case, the convex cylindrical plunger 1 fitted in the concave cylindrical portion 18 of the heating portion 16
7 is removed from the heating section 16, and a fixed amount of the oil-impregnated polymer molding material 1 is supplied to the concave cylindrical section 18. Next, the material 1 is heated to a predetermined temperature by the heater 5 and melted,
It is pressed by a plunger 17 that moves in the axial direction and injected into a mold 15, and is press-fitted into a molding portion (cavity) 12 from a gate 11 via a spool 9 and a runner 10, and is cooled and solidified in the mold. The process of opening the mold and taking out the solidified product in the molding unit 12 is the same as that using the plunger type injection molding machine of FIG.

Also in the case of this molding machine, by using the plunger 17, good sealing property in the molten resin injection step can be secured and sufficient pressure can be applied to the molten resin of the oil-impregnated polymer molding material. As a result, it is possible to manufacture a stable product.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. Table 1 shows an example of the composition of the oil-containing polymer molding material used in the present invention.

[0015]

[Table 1]

In the table, polyethylene resin (molecular weight 5 × 10 ^{3 to} 5 × 10 ⁴ ) as resin component, ultra high molecular weight polyethylene resin (molecular weight 1 × 10 ^{6 to} 5 × 10 ⁶ ) and dialkylphenyl ether oil as lubricating oil are shown. Shows the case of using. The above polyethylene resin is Mitsubishi Petrochemical Co., Ltd.
“Yukaron” (trade name) and ultra-high molecular weight polyethylene resin are available as “Miperon” (trade name) of Mitsui Petrochemical Co., Ltd. (Example 1): Oil-containing polymer molding materials A to E having the compositions shown in Table 1 were prepared and placed in a plunger type injection molding machine manufactured by British Butler Co., Ltd. with an inner diameter of 15 mm, an outer diameter of 20 mm and a length of 1.
A mold having a 5 mm concave molding portion was mounted to manufacture a cylindrical plain bearing, and the moldability was evaluated. For each oil-impregnated polymer molding material, add lubricating oil to polyethylene resin powder, heat to about 170 ° C, cool and make a jelly-like composition, grind with a mixer, etc., and further add polyethylene resin powder and ultra high molecular weight polyethylene. A resin powder and a kneaded powder or paste were used.

As comparative examples, the oil-impregnated polymer molding materials F to H shown in Table 1 were prepared and the moldability thereof was evaluated in the same manner. The results of the evaluation are also shown in Table 1. ⊚ is a material for which stable molding is possible and a product with excellent precision is obtained. ○ indicates a material that could be stably molded.

X indicates a material whose product shape could not be completely formed. The results of this test revealed the following regarding the material composition. The addition amount of ultra high molecular weight polyethylene resin is 20
It is preferably not more than 80% by weight, and the amount of lubricating oil added is preferably not more than 80% by weight. More preferably, the amount of the ultra high molecular weight polyethylene resin added is 2 to 15% by weight, and the amount of the lubricating oil added is 5 to 70% by weight. If the amount of the ultra high molecular weight polyethylene resin added is less than 2% by weight, the strength of the oil-impregnated polymer molded product may decrease, and if the amount of the lubricating oil added is less than 5% by weight, the lubricating function of the oil-impregnated polymer molded product may decrease.

On the other hand, if the amount of the ultra high molecular weight polyethylene resin added exceeds 20% by weight, the viscosity at the time of melting increases and molding becomes impossible. Also, the amount of lubricating oil added is 80% by weight.
If the amount exceeds the above range, the strength of the molded and solidified product is lowered, and deformation or the like occurs at the time of releasing from the mold, which is not preferable. (Example 2): A self-lubricating seal member 20 for a linear guide device shown in FIG. 3 was manufactured.

Incidentally, the seal member 20 is fixedly attached to the end surface of the slider body of a linear guide device (not shown) by bolts passing through the mounting holes 21. The inner surface side is provided with a seal lip 22 that abuts and seals the ball rolling groove on the side surface of the linear guide rail. By molding this with an oil-impregnated polymer molding material, the lubricating oil gradually exudes from the seal lip 22 to form a lubricating oil film in the ball rolling groove, which enables smooth movement of the slider including the slider body for a long period of time. It is a guarantee.

Material A of Table 1 as a material for molding oil-containing polymer
The mold for molding the seal member 20 shown in the figure
It is mounted on a plunger type injection molding machine manufactured by R company, and the temperature of the mold is heated to about 60 ° C, and the temperature of the cylindrical heating portion is set to about 180 ° C, and a powdery or paste oil-impregnated polymer molding material is used. Supply and injection pressure about 500kg / cm ² ,
Injection molding was performed at an injection rate of about 10 cm ³ / sec. After injection,
After cooling for about 20 seconds, the mold was opened and released to obtain a product. (Example 3): A linear motion sliding bearing 30 shown in FIG. 4 was manufactured.

The slide bearing 30 is integrally provided with a slide bearing main body 32 made of synthetic resin and a self-lubricating composition molded product 33 made of an oil-impregnated polymer molding material surrounding the outer periphery thereof. At least a part of the self-lubricating composition molded product 33 is exposed on the sliding surface 31a of the bearing. When the sliding surface 31a is brought into contact with a sliding surface of a rail (not shown) and linearly moved, the lubricating oil contained in the self-lubricating composition molded product 33 gradually exudes for a long period of time and is supplied to both sliding surfaces. A good lubricating state is always maintained.

Nylon 66 is used as the resin for the sliding bearing main body 32 of the core portion, and the self-lubricating composition 33 made of the oil-impregnated polymer molding material A shown in Table 1 is applied to the outer peripheral portion of the nylon 66.
Injection molding was performed using a plunger type injection molding machine manufactured by LER. (Example 4): Oil-impregnated polymer-enclosed rolling bearing 4 shown in FIG.
0 was produced.

The rolling bearing 40 includes a rolling element 40c held by a cage 40d between an outer ring 40a and an inner ring 40b.
And a self-lubricating filler 42 made of an oil-impregnated polymer molding material in the space between the outer ring 40a and the inner ring 40b.
Is filled and sealed. The filler 42 blocks the inside of the bearing from the outside to perform an anticorrosive action, and gradually releases the lubricating oil for a long period of time to gradually roll out the rolling element 40c and the outer ring 40.
It is supplied to each raceway surface of the inner ring 40b and the inner ring 40b to perform good lubrication.

FIG. 6 shows a plunger transfer molding machine [HDF-3 manufactured by North Cross Co., Ltd.] used to mold the oil-filled polymer molding material into the rolling bearing 40 to mold the filler 42.
7-S] 43 and the mold 44. The mold 44 was attached to the transfer molding machine 43, and the rolling bearing 40 was mounted in the mold 44. After maintaining the temperature of the mold 44 at about 80 ° C. and heating the heating section 16 which is the transfer pot of the transfer molding machine 43 to 170 to 210 ° C. by the heater 5, the convex cylindrical plunger 17 is moved to the heating section 16. It was extracted from the concave cylindrical portion 18, and a powdery or paste oil-containing polymer molding material was supplied into the concave cylindrical portion 18. In the case of this example, the oil-containing polymer molding material B shown in Table 1 was used. After the material B is preheated for about 30 to 70 seconds to be melted, the plunger 17 inserted into the die 44
It was shot inside. The injected oil-impregnated polymer molding material passes through the spool 44a and the runner 44b, and then the outer ring 40 of the bearing 40.
a, the inner ring 40b, the core pin 44c, and the mold 44, and is press-fitted into the bearing inner space as a concave shaped portion. Injection time is 0.8-2.0 seconds, injection pressure is 300-600kg / c
It was m ² . After cooling, the mold 44 was opened, and the rolling bearing 40 containing the filler as a product was ejected by ejecting it with the ejector pin 44d.

Since the rolling bearing 40 of this embodiment has the metal cage 40d having a high rigidity, the material B having a larger amount of lubricating oil is used as the oil-impregnated polymer molding material for molding the filler 42. (A molded product having a lower hardness than the materials C and D having a small lubricating oil content) can be used. (Example 5): A self-lubricating seal member 50 for a ball screw shown in FIG. 7 was manufactured.

The seal member 50 has a ball screw nut 53 screwed to a screw shaft 52 through rolling of a ball 51.
It is a self-lubricating seal member that is attached to the end portion of and is capable of closely adhering to the screw groove 52a of the screw shaft 52 and performing a sealing function and a lubricating function at the same time. This product was manufactured as follows.

A mold having a concave shaped portion corresponding to the product shape was attached to a plunger type transfer molding machine [HDF-37-S manufactured by Northern Cross Co., Ltd.] as in Example 4, and the temperature of the mold was changed. Is maintained at about 60 ° C., the heating part of the transfer pot of the transfer molding machine is heated to 200 to 210 ° C. by a heater, and then powdery or paste-like oil-containing polymer is placed in the concave cylindrical part of the heating part in the same manner as above. The molding material was supplied. In the case of this example, the oil-containing polymer molding material C shown in Table 1 was used. The material C was preheated for about 80 to 100 seconds to be melted and then injected into the mold by the inserted plunger. Injection time is 0.8 to 2.0 seconds, injection pressure is 150 to 4
It was 00 kg / cm ² . After cooling, the mold was opened and the self-lubricating seal member 50 as a product was taken out. (Example 6): A self-lubricating cage 60 for a ball bearing shown in FIG. 8 was manufactured.

In this case, a plunger type injection molding machine manufactured by BUTLER was used, and the material C shown in Table 1 was used as a material for forming an oil-containing polymer. A mold having a concave molding part corresponding to the product shape is attached to the plunger type injection molding machine, and the temperature of the mold is heated to about 60 ° C. Alternatively, a paste-like oil-containing polymer molding material C is supplied to provide an injection pressure of about 50.
Injection molding was performed at 0 kg / cm ² . After the injection, it was cooled for about 20 seconds, the mold was opened and released to obtain a product. (Comparative Example 1): An experiment was carried out in which the self-lubricating seal member 20 for a linear guide device shown in FIG. 3 of Example 2 was molded using an in-line screw type injection molding machine.

Material A of Table 1 as a material for molding oil-containing polymer
When the molding die for the seal member 20 was mounted on an in-line screw type injection molding machine and the powdery oil-impregnated polymer molding material A was supplied from the hopper into the screw cylinder, it was impossible to measure and molding was performed. could not.
One of the causes is the screw cylinder 1 which is the heating part of the inline screw type injection molding machine, as shown in FIG.
This is because the clearance (clearance) 103 between 01 and the screw 102 inserted therein is too large. That is, since the oil-impregnated polymer molding material contains the lubricating oil, it easily slips on the screw cylinder 101. This slippery molding material is screw 102
It was not possible to rotate and flow in the axial direction to send out. When the molding material is only a resin containing no lubricating oil, it is easy to make it flow in the axial direction.

At the tip of the screw 102, the check member 10 is axially movable in the outer peripheral groove 102a.
5 is inserted so that the pressurized molding material in the screw cylinder 101 can be sealed. However, the cylindrical check member 105 has a much shorter axial length than the plunger, and it is difficult to secure a large sealing area, and the airtightness between the inner wall of the screw cylinder 101 is not sufficient. Absent. Therefore, the fact that the injection pressure for driving the screw 102 in the axial direction to push out the resin material from the nozzle 106 into the mold is weaker than that of the plunger type molding machine can be said to be a cause of unmolding.

[0032]

As described above, according to the method for producing an oil-impregnated polymer molded product of the present invention, the oil-impregnated oil supplied to the cylindrical portion of the molding machine using a plunger type injection molding machine or transfer molding machine. Since the polymer molding material is made to flow to the concave molding portion that is the cavity of the mold, the fitting length between the cylindrical portion and the plunger is sufficiently long so that the distance between the plunger and the cylindrical portion is large. Airtightness can be secured, and the oil-containing polymer molding material supplied to the cylindrical part in fixed amounts can be pumped into the mold cavity with a strong pressing force, and as a result, oil-containing polymer molded products of various shapes. The effect of being able to be mass-produced stably with high productivity is exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating an outline of a plunger type injection molding machine used in the present invention.

FIG. 2 is a cross-sectional view illustrating the outline of a transfer molding machine used in the present invention.

3 is a perspective view of a self-lubricating seal member for a linear guide device manufactured in Example 2. FIG.

4A is a cross-sectional view of a linear motion slide bearing manufactured in Example 3, and FIG. 4B is a bottom view thereof.

FIG. 5 is a sectional view of essential parts of an oil-impregnated polymer-encapsulated rolling bearing manufactured in Example 4.

6 is a cross-sectional view illustrating a method of manufacturing the oil-impregnated polymer-encapsulated rolling bearing shown in FIG.

FIG. 7 is a sectional view of a self-lubricating seal member for a ball screw manufactured in Example 5.

FIG. 8 is a perspective view of a self-lubricating cage for ball bearings manufactured in Example 6.

FIG. 9 is a sectional view partially showing a screw cylinder and a screw of an in-line screw type injection molding machine.

[Explanation of symbols]

1 Oil-containing polymer molding material 3 heating section 4 Cylindrical part 6 Plunger 8 mold 12 Molding section 15 Mold 16 heating part 17 Plunger 18 Cylindrical part 44 mold

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI B29L 31:26 B29L 31:26 C10N 40:02 C10N 40:02 40:06 40:06 50:08 50:08 70:00 70 : 00 (56) Reference JP-A-51-6243 (JP, A) JP-A-1-198316 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/00- 45/84

Claims (6)

(57) [Claims] 1. The content of lubricating oil is 20 to 80% by weight.
And oil-containing polymer molding material in powder or paste form
Material is supplied to the concave cylindrical portion of the heating portion, and the heated material is pressed by a plunger fitted in the cylindrical portion to flow into the concave molding portion of the mold. . 2. An oil-containing porosity obtained by the method according to claim 1.
Sealing member for linear guide device consisting of Lima molded product. 3. An oil-containing porosity obtained by the method according to claim 1.
A cage for ball bearings made of Lima molded products. 4. The cage is held between the outer ring and the inner ring.
In the space between the outer ring and the inner ring where rolling elements are arranged
And an oil-impregnated polymer molded product obtained by the method according to claim 1.
Filled and sealed with a self-lubricating filler consisting of
Rolling bearing. 5. An oil-containing porosity obtained by the method according to claim 1.
Self-lubricating seal part for ball screw consisting of Lima molded product
Material. 6. A plain bearing main body made of synthetic resin, and the outside thereof.
Self-lubricating composition consisting of oil-containing polymer molding material surrounding the circumference
The self-lubricating composition molded product is integrated with the molded product.
Is an oil-impregnated polymer molded product obtained by the method according to claim 1.
A direct acting slide bearing.