JPH0396716A - Race for roller bearing - Google Patents

Abstract

PURPOSE:To lower the rate of deformation at high temperature and to have flexibility so as to easily incorporate a rolling element and to improve the mechanical strength and chemical resistance by forming a race by a composite composed of bridged PPS resin obtained by bridging PPS resin and fibrous reinforcement. CONSTITUTION:A race 1 has a click portion 2 on the upper portion, wherein a rolling element 4 such as a steel ball or the like is incorporated in a pocket portion 3 having a narrow opening and rotatably retained. Bridged PPS resin has the welding viscosity of 350 - 3,000 pores after polymerization. In order to bridge the polymerized PPS resin, heating under the melting point in the air or addition of a cross linking agent or a branching agent is performed. As a method of mixing PPS resin, fibrous reinforcement and fluororesin, they are dry mixed using a mixer such as a Henschel mixer, a ball mill, a tumbler mixer or the like, and then fused and mixed by a heat roll, a kneader, a ban bury mixer, a fusion extruder, or the like to be pelletized as a forming material. The pelletized material is fused and formed into a designated form as a race for a rolling bearing by an injection molding machine.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a cage for a rolling bearing made of plastic that can be used at high temperatures.

[Conventional technology]

As is well known, plastic rolling bearing cages (
As for cages (hereinafter referred to as cages), so-called nylon cages made of polyamide resin are widely used, which have excellent mechanical properties such as moldability and flexibility, and productivity such as raw material cost. As shown in FIG. 1, such a cage 1 has a claw portion 2 at the top and a pocket portion 3 with a narrow entrance and exit, and a transfer body 4 such as a steel ball is incorporated therein so as to be freely rotatable. It is something to keep. However, this nylon retainer 1 is susceptible to nylon under continuous use at temperatures above 120"C, or under conditions in which it comes into contact with oils or other acidic agents to which extreme pressure additives or other additives have been added. Polyphenylene sulfide resin (hereinafter referred to as polyphenylene sulfide resin) is an alternative material to nylon, which is used under high temperature conditions and is relatively inexpensive. , abbreviated as pps resin),
It has excellent heat resistance, chemical resistance, and formability.
This PPS resin is a polymer consisting of repeating units represented by the general formula 101.
It is obtained by reacting in an ξ-do solvent such as methylpyrrolidone or dimethylacetamide or a sulfone solvent such as sulfolane, and the PPS resin at this stage is considered as the polymerized product. Furthermore, there are two types of PPS resins: crosslinkable pps resins (also called branched PPS resins) and linear pps resins. The former crosslinkable pps resin is produced by heating a low-viscosity, low-molecular-weight PPS resin with a melt viscosity of about 20 to 100 poise in air to below its melting point to cause oxidation crosslinking to increase the melt viscosity. Alternatively, a crosslinked or branched structure is introduced by intentionally adding a crosslinking agent or a branching agent to increase the melt viscosity. However, although the crosslinkable PPS resin obtained in this way has an increased melt viscosity, that is, improved heat resistance, it is considerably brittle and lacks flexibility. It was unsuitable as a material for a cage that requires flexibility when incorporated into a cage. On the other hand, linear PPS resin is a PPS resin whose molecular chains have been lengthened to a high molecular weight in a straight chain during the polymerization stage, and is characterized by being extremely flexible and tough compared to the above-mentioned crosslinkable PPS resin. The use of this linear pps resin as a cage for rolling bearings was proposed in JP-A-64-79419.
It is disclosed in However, although bearing cages made of this linear PPSI fat are certainly easy to assemble during assembly, they have poor thermal stability and high temperature (over 150°C)
It has poor mechanical properties such as creep resistance, and when used as a cage for bearings, the cage deforms due to centrifugal force and comes into contact with the outer ring, generating abnormal frictional heat. , which deteriorated the lubricant and reduced the performance of the bearing. [Problems to be Solved by the Invention] This invention solves the above-mentioned linear pps resin or crosslinkable PP resin.
To solve the problems of cages made of S resin, to provide a cage that has the necessary flexibility, makes it easy to incorporate transfer bodies, has mechanical strength and chemical resistance, and has a low deformation rate at high temperatures. This is considered a technical issue. Means for Solving the rim Problem] In order to solve the above problem, in the first invention, a crosslinkable PPS resin obtained by crosslinking a pps resin having a melt viscosity of 350 to 3000 poise after polymerization and a fibrous A cage is formed from a composition consisting of a reinforcing material, and in a second invention, a cage for a rolling bearing is made of a ma material made of a crosslinkable pps resin of the first invention, a fibrous reinforcing material, and a fluororesin. It was formed. (Function) The melt viscosity after polymerization, which is the material for the cage of this invention, is 3.
Crosslinkable PPS resins obtained by crosslinking PPS resins of 50 to 3000 poise are flexible and have excellent mechanical properties at high temperatures. Therefore, such crosslinkable P
The cage made of XJL, which is composed of two components of PS resin, fibrous reinforcement material, and three components of fluororesin, has appropriate flexibility, does not break during assembly, and is easy to assemble. Excellent, with low deformation rate at high temperatures during use. The crosslinkable PPS resin in this invention has a melt viscosity of 350 to 3000 poise after polymerization, preferably 500 to 1000 poise. This is because PP has a melt viscosity of less than 350 poise after polymerization.
This is because a cross-linked PPS resin made by cross-linking S resin lacks mechanical strength and flexibility, and if such a cross-linked PPS resin is used as a cage, it is likely to be damaged when a transfer body is installed. Moreover, if it is larger than 3000 poise, the creep resistance at high temperatures is poor, and when used as a cage for a bearing, the cage will be deformed. Crosslinking of the PPS resin after polymerization is carried out by heating it in air below its melting point or by adding a crosslinking agent or a branching agent, as in the above-mentioned crosslinking method. The crosslinkable PPS resin thus produced has a melt viscosity of 78
00 to 40,000 poise, preferably l400 to
It may be 20,000 poise, more preferably l5
00 to 10,000 poise is even better. In that case,
Crosslinkable PPS resins with a melt viscosity of less than 1400 poise are undesirable because their mechanical properties such as creep resistance deteriorate at high temperatures of 150°C or higher, and they tend to deform.
A crosslinkable pps resin larger than 20,000 poise is undesirable because even if the melt viscosity before crosslinking is 350 to 3,000 poise, the shapeability is poor and the flexibility is reduced, making it difficult to incorporate the transfer body into the cage. ．． The conditions for measuring the melt viscosity described above are as follows. Measurement temperature = 300°C, orifice 2 hole diameter 1mm, length 10m measurement load
: 20kg/ai, Measuring device: Koka type flow tester Preheating time: 6
Furthermore, regarding the thermal stability of the crosslinkable pps resin, it is preferable that the rate of change in melt viscosity after 6 minutes and 30 minutes of preheating is in the range of -50 to 150% under the above melt viscosity measurement conditions. The rate of change is expressed by the following formula. P. -P6 Rate of Change -XIOO P, Examples of crosslinkable PPS resins that satisfy the above conditions include T-4 (2) and T-007 manufactured by Toblen.

Next, the fibrous reinforcing material included in this invention is P
There is no particular limitation as long as it can withstand the temperature when PS resin is melted and shaped, and the fibrous reinforcing material may include:
Glass fiber, carbon fiber, graphite fiber, wollastonite, silicon carbide whisker, sapphire whisker, heat-resistant inorganic single fiber such as steel wire, copper wire, stainless steel wire, boron or silicon carbide fiber with tungsten core wire or carbon fiber, etc. Examples thereof include heat-resistant inorganic composite fibers such as boron fibers or silicon carbide fibers, and heat-resistant organic fibers such as aromatic boria bulk fibers. In addition, the above-mentioned fibrous reinforcing materials include:
Glass fiber is particularly preferred.

As this glass fiber, SiOz, B20, AIt
Oz, CaO, NatO, K. It is obtained from inorganic glass containing O, etc., and generally includes alkali-free glass (abbreviated as E glass) and alkali-containing glass (abbreviated as C glass and A glass). Preferably, the length is from 0.1 to 10 mm, and the wire diameter is preferably 15 μm or less, particularly 10 fm or less. This is because, if glass fibers with a fiber diameter larger than 1 sttm are used, the resulting plastic retainer for rolling bearings will lack flexibility and will be difficult to assemble during assembly. In addition, in order to have affinity with the PPS resin, the fibrous reinforcing material is used as a sizing agent containing a silane coupling agent such as anosilane, epoxysilane, or mercaptosilane, a chromium-based coupling agent, and a sizing agent for the purpose of focusing. It may also be one that has been treated with a chemical or the like.

Examples of the fluororesin in the present invention include tetrafluoroethylene resin (abbreviated as PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (abbreviated as PFA), and tetrafluoroethylene-hexafluoropropylene copolymer. , ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-fluoroalkyl vinyl ether-fluoroolefin copolymer, polytricfluoroethylene, polyvinylidene fluoride, and the like.

The content ratio (weight %) of each component in the present invention is as follows.

Crosslinkable pps resin (A) Fibrous reinforcing material (B) Fluorine resin (C) ■ A:B=30-98: 70-2, preferably 5
0~95:50~5, ■ A:B:C=45~8g: 10~40:2~1
5. Preferably 65-85:12-35:2-10, if the amount of fluororesin added is less than 2%, flexibility will be lacking, and 15%
If it exceeds this level, the mechanical strength at high temperatures will deteriorate, which is not preferable.

Furthermore, various fillers may be added as long as they do not impair the effects of this invention. Such fillers include aromatic polyetherketone resin, polyether oxide resin, polyether sulfone resin, boria-dimide resin, heat-resistant polyamide resin, phenolic resin, aromatic polyester resin, polyimide resin, fluororesin, Organic heat-resistant polymer materials such as silicone resins, inorganic powders for improving thermal conductivity such as graphite or metals or oxides such as zinc, aluminum, and magnesium, glass beads, silica balloons, diatomaceous earth, asbestos, magnesium carbonate, and calcium carbonate. , inorganic powders such as calcium oxide, calcium fluoride, and calcium hydroxide, inorganic powders for improving lubricity such as molybdenum disulfide, graphite, carbon, miryoku, talc, and molybdenum trioxide, and iron oxide, cadmium sulfide, Examples include inorganic pigments such as cadmium selenide and carbon black, silicone oils, ester oils, fluorine oils, polyphenylene ether oils, waxes, and internal lubricant additives such as zinc stearate. The method of mixing the pps resin, fibrous reinforcing material, fluororesin, and other additives described above is not particularly limited, and dry mixing is performed using a mixer such as a Henschel mixer, a ball tanker, or a tumbler mixer. After that, it is melt-mixed using a heated roll, kneader, Banbury mixer, melt extruder, etc. to form a molding material, such as pellets, and then melt-molded into a predetermined shape as a cage for rolling bearings using an injection molding machine, etc. good. The molding conditions are not particularly limited, and normal molding conditions for PPS resin are sufficient. The raw materials used in Examples and Comparative Examples of this invention are collectively shown below. Regarding PPS resin, melt viscosity after polymerization: P, melt viscosity after crosslinking: P2 (after 6 minutes). P
x (30 minutes later) is also written.

■Crosslinkable pps resin (FT-4 (2) manufactured by Toprene Co., Ltd.,
P + = 700 poise, Pt = 1840 poise,
P3-1350 poise) ■Crosslinkable PPS resin (Toprene: TX-001,
P, = 700 poise, P z = 1030 poise,
P, = 13400 poise) ■Crosslinkable pps resin (manufactured by Torbren: prototype PPS (
1), P + = 700 poise, Pg""1880 poise, P, -1530 poise) ■Crosslinkable PPS resin (manufactured by Toprene: Prototype P P
S (2), P, = 700 Poise, P. =2320 poise, P, -2150 poise) ■Crosslinkable PPS resin (Toprene: T-4 (1),
PI-300 Poise, P. =2450 poise, P3=
3520 poise) ■Linear PPS resin (manufactured by Kureha Chemical Industry Co., Ltd.: KPS#21
4. Melt viscosity - 1400 poise) ■Glass fiber (manufactured by Asahi Glass Fiber Glass Co., Ltd.: CSO30E404, fiber-based 6μ) ■Glass fiber (manufactured by Asahi Glass Fiber Glass Co., Ltd.: CSO30EF-562, fiber-based 6pm) ■Fluororesin PTFE ( Kitamura Co., Ltd.: KTL-610) [Phase] Fluororesin PFA (Mitsui DuPont Fluorochemical Co., Ltd.: Liver-10) The above raw materials were mixed using Henschel ξ Kisser in the proportions shown in Tables 1 and 2. The mixture was dry-mixed and supplied to a twin-screw melt extruder, where it was melt-blended and granulated at a cylinder temperature of 270-330'C and a screw rotation speed of 50-100 rpm.Then, the cylinder temperature was 280-340'C.
'C, mold temperature 100~150'C, injection pressure 500~
The cage 1 of the bearing 5203 as shown in FIG. 1 was injection molded under the condition of 1000 kg/cJ, and the following test was conducted.

<1) Integration test during assembly As shown in Figure 2, it was actually assembled into the bearing body 5 using a mini-press and the degree of damage caused by the rolling elements 4 (steel balls) to the claw portion 2 of the cage 1 was measured. The assemblability of the steel balls was investigated and judged according to the criteria shown below, and the results are shown in Tables 1 and 2. ■Degree of damage to the claws of the retainer: ○...No damage at all Δ...Slight damage ×...Significant damage ■Easy to install the rope ball: O・・・・・・・Δ that can be easily installed during installation.
...There is a little resistance when assembling × ...There is considerable resistance when assembling Table 1 Note * There are scratches on the outer periphery of the cage (2) Durability test whistle of the cage claws Shown in Figure 3 As shown in FIG.
A rod 7 equipped with a copper ball with a diameter of 7.16 mm is inserted and withdrawn using a testing machine 8 at a speed of 50 times/min until the claw portion 2 of the retainer 1 breaks. 71 times)
1, and the values are shown in Table 1. It can be said that the greater the number of times of loading and unloading, the greater the fatigue strength of the claw portions 2 of the cage 1, and the higher the safety factor when incorporating the transfer body 4 of the cage 1 in the manufacturing process.

(3) Cage deformation rate measurement test lubricant (manufactured by Nippon Oil Co., Ltd.: urea-based grease, U295)
Bearing 6 sealed with fluorine rubber and sealed with 0.8g of
203 was operated for 200 hours using an operating test machine under the conditions of rotation speed 1500 rpm, thrust load 6.8 kgf, /M degree 180°C, and the dimensional deformation rate of the cage outer diameter was measured and shown in Table 1. The smaller the dimensional deformation rate is, the less the cage is deformed.

(4) Lubricant deterioration degree determination test Lubricant after 200 hours of continuous operation under exactly the same conditions as test (3) (Nippon Oil Co., Ltd.: Urea-based grease, U295)
The degree of deterioration was determined and is also listed in Table 1, ○...
・Discoloration, no deterioration Δ・・・Discoloration, slight deterioration×・・・・・・
As is clear from Tables 1 and 2, which show discoloration and considerable deterioration, the cage made of crosslinkable PPS resin and fibrous reinforcing material has a melt viscosity of 78 poise or more after polymerization (Table 1). and Examples 1 to 5 in Table 2) are crosslinkable pps resins whose melt viscosity after polymerization is smaller than 350 poise (Comparative Examples 1 and 3 in Table 1) and straight PPS resins.
Compared to resin (Comparative Examples 2 and 4 in Table 1), it has excellent ease of assembly during assembly and durability of the claws of the cage, and has a low deformation rate in bearings operated at high temperatures. Does not deteriorate lubricant.

〔Effect of the invention〕

As is clear from the above description, the cage of the present invention is flexible and easy to incorporate into the bearing, and even when used at high temperatures, the deformation rate is low, so the bearing will not be damaged. It has the heat resistance and chemical resistance inherent to pps resin, and its application fields are extremely wide, including the automobile-related industry, the i-device-related industry, and the N.P.S. It is ideal as a cage for rolling bearings used in the mechanical/electronic industry and many other fields.

[Brief explanation of drawings]

FIG. 1 is a perspective view illustrating the main parts of a cage for rolling bearings;
Figure 2 is a cross-sectional view showing the relationship between a rolling bearing cage and a bearing to examine the ease of incorporating steel balls, and Figure 3 is a plan view of a testing machine illustrating the durability test of the claws of a rolling bearing cage. It is a diagram. DESCRIPTION OF SYMBOLS 1... Rolling bearing cage, 2... Claw portion, 3... Pocket portion, 4... Rolling element, 5......
Bearing body.

Claims (3)

[Claims] (1) A cage for a rolling bearing made of a composition comprising a crosslinkable polyphenylene sulfide resin obtained by crosslinking a polyphenylene sulfide resin having a melt viscosity of 350 to 3000 poise after polymerization and a fibrous reinforcing material. (2) A cage for rolling bearings made of a composition consisting of a crosslinkable polyphenylene sulfide resin obtained by crosslinking a polyphenylene sulfide resin having a melt viscosity of 350 to 3,000 poise after polymerization, a fibrous reinforcing material, and a fluororesin. . (3) The cage for a rolling bearing according to claim (1) or (2), wherein the crosslinkable polyphenylene sulfide resin has a melt viscosity of 1,400 to 20,000 poise after crosslinking.