JPS62157782A - Spanner made of ceramics - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to spanners, wrenches, and similar tools thereof, in which at least the gripping portion that contacts a workpiece is made of a ceramic material.

(Prior Art) Conventionally, spanners used for tightening nuts, etc., have generally been made of alloy steel such as vanadium steel due to the requirements for high strength and high torque resistance.

Such alloy steel spanners have the advantage of being high strength and being able to be provided at a relatively low cost. However, on the other hand, due to their conductivity, they can cause electrical circuit short circuit accidents and human injury depending on the usage situation. There is also a risk of electric shock, so it is not suitable for work on 1m-long installations such as switchboards in electrical and electronic fields. Furthermore, when used in a device equipped with a magnetic material, it is undesirable because it causes magnetic changes.

General tools, such as those using a ceramic material for the simple shaped part of the driver shaft, are also described in JP-A-59-107865, but they have a clamping part like a spanner, and the driver shaft is different. Conventionally, it has been considered difficult to apply this method to spanners, which have an incomparable size and complicated shape, and the torque generated in each part is also complicated.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is to solve the above-mentioned problems of applying ceramic materials to conventional spanners, have mechanical strength similar to tools made from alloy steel such as vanadium steel, and The object of the present invention is to realize ceramic spanners that have sufficient corrosion resistance and electrical insulation properties and are suitable for use in the electrical and electronic fields.

[Means for solving problems]

The present invention provides a ceramic material that satisfies such required properties, especially when a zirconium oxide ceramic material having a tetragonal crystal structure is used under specific conditions, and has excellent electrical insulation properties as well as a ceramic material made of conventional alloy steel. This is based on the novel finding that it has similar mechanical strength and is particularly suitable for tools that require high torque, such as spanners.

The spanner of the present invention is made of a sintered body whose main component is at least zirconium oxide having a tetragonal crystal structure.

The above-mentioned zirconium oxide may have only a tetragonal crystal structure or coexist with cubic zirconium oxide, but 20 mol% or more must be composed of tetragonal crystals, and preferably It is preferable that 70 mol% or more be tetragonal.

Partially stabilized zirconium oxide undergoes mantenside transformation from tetragonal to monoclinic crystal, that is, microcracks, when stress is applied from the outside.If excessive stress is applied, such as with a spanner, The microcranks present in the monoclinic portion act as a starting point, causing stress concentration, leading to stress fracture. Therefore, for tools such as spanners that require high mechanical strength, it is important to minimize the monoclinic content of the sintered body, preferably 1.
The content should be 0.0 mol% or less, and preferably substantially 0 mol%.

If the amount of tetragonal zirconium oxide in the sintered body is less than 20 mol%, it will not be able to sufficiently absorb strain when subjected to mechanical force, and if cracks occur, they will not propagate. I can't suppress it.

The partially stabilized zirconium oxide is YzC1+.

It is most preferable to use stabilizers such as Cab, MgO, Ce0z, etc. in a solid solution in a somewhat larger amount than in conventional ones, particularly those partially stabilized with YtOi, and the amount added is preferably 1 to 6 mol %. 6 to 12 for MgO and CaO
Mol%, 6 to 10 mol% for CeO % is preferred.

In the spanner of the present invention, tetragonal ZrO partially stabilized with the above oxide is used to improve physical properties such as hardness 1 bending strength.
, it is effective to contain 10.0 to 35.0% by weight of M2O3, and when sintering the spanner of the present invention, Crz03, YzOs, MgO, etc. are used as sintering aids to add 10.0 to 35.0% by weight. It is preferable to add 1% by weight or less.

When A120x is added to Zr0z, the powder may be mechanically mixed together, or it may be chemically synthesized in the form of oxychloride.

In addition, in the present invention, AIz is further added to the tetragonal ZrO2.
By adding a whisker having characteristics such as a crack deflection effect due to a high aspect ratio in place of Ch or together with Al2O3, the toughness value can be increased and the properties required for a spanner can be further satisfied.

Such whiskers are preferably silicon nitride whiskers, and a sintered body containing 6.0 to 19.0% by weight has a toughness value that is 1.4 times or more higher than that of a tetragonal zirconium oxide single sintered body. Show improvement. Further, although strength improvement is similarly observed when silicon carbide whiskers are added, this is not so preferred when high insulation properties are required.

If the amount of each whisker added is less than 6.0% by weight, no significant improvement in physical properties will be observed, and if it exceeds 19.0% by weight, various physical property values will decrease.

The attached drawing shows an example of the structure of the spanner according to the present invention.

FIG. 1 is a diagram showing the overall structure. The figure shows an example in which the handle 1 and the head 2 are formed separately, and the head 2 made of the zirconia ceramics is attached to the tip of the handle 1.
The handle 1 may be made of the same ceramic material as the head 2.

As the handle 1, any material can be used as long as it is an electrically insulating material such as a synthetic resin such as FRP and has high strength.

The tetragonal zirconium oxide ceramics used for the spanner head are silicon nitride and Sialon.

It has the advantage of extremely high fracture toughness compared to silicon carbide ceramics, but when compared to alloy steel spanners,
There is a drawback that chipping and chipping are somewhat likely to occur.

For this reason, the edge portion 3 is as shown in FIG. 2 (a) when viewed from the thickness direction.
), the corner 5 should have a roundness of about 0.5 to 2R, or the bevel angle 6 should be 120 mm as shown in Fig. 2(b).
It is preferable to set it as an obtuse angle of about 6.

Further, as shown in FIG. 3, it is preferable that the tip 7 of the spanner tip edge portion 3 has a curved surface of about IR to 5R.

Furthermore, as shown in FIG. 4, it is best for the edge inner corner 4 to have as large a radius as possible, and to set it from 2R to IOR.

By doing so, chipping and chipping during use can be largely eliminated.

Furthermore, if a larger torque is applied to the wrench, a wrench of the same shape as a conventional wrench will easily crack and break as shown in Figure 5C. It is most preferable to have a substantially circular side surface shape, such as A indicated by the solid line in FIG.

That is, for this reason, the ratio of width across flats (S)/outer width (Sl) and thickness are made larger than JIS (84630). The ratio varies depending on the magnitude of the torque applied to the spanner, but is generally about 1.2 to 2 times the JIS standard. Furthermore, the center a of the arc of the head, which is in contact with the outer width (Sl), is moved toward the bottom of the mouth of the spanner. Its position is from point b to S/
It is preferable that it is within 4. Further, it is desirable that the radius of the circular arc contacting the handle is large, but it is generally preferable that the radius be larger than the outer width of the spanner head.

The ceramic spanner according to the present invention generally has a purity of 99
．． Adding an organic binder to partially stabilized zirconium oxide having 9% or more and an average particle size of 0.3 to 1.0 μm,
It is granulated, slurried or pelletized, then press molded, slip cast molded or injection molded to produce a green molded body of a desired shape, and a degreasing method suitable for each molded body, such as normal pressure degreasing or pressure degreasing, is carried out. Next 1450±50
Spanners that have been fired at ℃ for 2 hours or further subjected to HIP treatment, or hot-pressed and sintered using hot isostatic pressing (HIP treatment) at 1350 to 1460℃ under an argon atmosphere at 1000 atm or higher. Alternatively, the desired ceramic spanner is obtained by direct pressure sintering using a hot press method at 1400±50° C. and 3150 kg/aA or more.

The ceramic spanner obtained in this way has high strength and excellent electrical insulation properties at room temperature, and can be used for electricity.

Useful in electronic and chemical fields.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

Example 1 To 100 parts by weight of zirconium oxide powder with a purity of 99.9% or more and an average particle size of 063 μm partially stabilized with yttrium oxide, 0.3 parts by weight of ammonium acrylate as a deflocculant, acrylic emulsion binder, etc.゛10
Multi-unit area Kuromen/Yoken 1O-5 Raiden 1R and pure water 30.
0 parts by weight was added, mixed and dispersed in a roller mill for 24 hours to form a slurry, aged for about 1 day and night, and then defoamed in vacuum. The slurry was pressure cast into a plaster mold of a desired shape at 1.5 atmospheres to obtain a green molded body. The obtained molded body is 4
After drying for one day and night in a dryer set at 0℃,
℃ Degreasing under vacuum, further temperature increase rate 1℃/w in oxidizing atmosphere
The sintered body was heated to 1470'c, held for 2 hours, and left to cool to obtain a sintered body. Subsequently, at 1460°C under argon atmosphere,
An integrally molded spanner was obtained by HIPing at 800 atmospheres or higher.

Table 1 shows the physical properties and electrical properties of the spanner obtained as described above.

Example 2 Zirconium oxide powder partially stabilized with yttrium oxide, purity 99.9% or more, average particle size 0.5 μm 80.0
Weight%, purity 99.99%, average particle size 0.4 μm
To 100 parts by weight of mixed powder consisting of 20.0% by weight of aluminum oxide powder, 10 parts by weight of acrylic resin was added as a binder.
．． 0 parts by weight, 5.0 parts by weight of ethylene-vinyl acetate copolymer, 3.0 parts by weight of polystyrene, 2.0 parts by weight of dibutyl phthalate as a plasticizer, and 2.0 parts by weight of zinc stearate as a lubricant. The mixture was put into a kneader set at C±5°C, heated and kneaded for 30 minutes, then taken out from the kneader and coarsely powdered using a pelletizer. Next, this beret is 1
The pellets were placed in a twin-screw extrusion machine set at 40°C±2°C to produce injection molding pellets of equal size.

Then, using an injection molding machine, the injection temperature was 180'C and the injection pressure was Too kg/CIl! Injection molding was carried out at a mold temperature of 40"C, holding pressure and cooling for 30 seconds.Next, after degreasing at a pressure of 500C and a temperature increase rate of 10C/hr, the mold was held at 1450C for 2 hours in an oxidizing atmosphere. A preliminary sintered body was obtained.Furthermore, it was heated at 1350 to 1460°C at 1000°C in an argon atmosphere.
A spanner was obtained by performing the TeIIIP treatment above atmospheric pressure.

Table 1 shows the physical properties and electrical properties of the ceramic spanner obtained by the above method.

Chapter 1 Table *M conversion rate was calculated using the following formula.

M= ((E+F)/(D+F+F)) X100 where D: Diffraction intensity of tetragonal zirconium oxide 111 plane E:
Diffraction intensity F of monoclinic zirconium oxide 111 plane: Diffraction intensity of monoclinic zirconium oxide 111 plane Example 3 Zirconium oxide powder partially stabilized with yttrium oxide, purity 99.9% or more, average particle size 0.7 μm 72. 0
Aluminum oxide powder 15.6% by weight and purity 99.99%, average particle size 0.5 μm and purity 99.
A composition powder consisting of 12.4% by weight of silicon nitride whisker powder of 0% or more was pulverized and mixed in a ball mill for 20 hours, and the aspect ratio of the silicon nitride whiskers was adjusted to be 3 to 200 and granulated.

Next, the above powder was loaded into a carbon mold having a desired shape, and the temperature was 1430±20°C and the pressure was 200kil.
/cot for 1.0 hour and hot pressed to obtain a spanner.

The ceramic spanner 5 thus obtained exhibited a fracture toughness value approximately 1.5 times that of a single tetragonal zirconium oxide spanner.

〔Effect of the invention〕

The zirconium oxide ceramic spanner according to the present invention has excellent electrical insulation properties and high strength, is a non-magnetic material and is chemically stable, and can be used in the assembly and adjustment of equipment in the electrical and electronic fields. The generation of sparks due to short circuits can be prevented, and electric shock to the human body can also be prevented.

Further, even when using a device containing a magnetic material, since it is not magnetized, there is no risk of causing magnetic changes. Since it is made of ceramics, we can expect the effect to be sufficient.

[Brief explanation of drawings]

The attached drawings are diagrams showing aspects of the spanner according to the present invention. FIG. 1 is an overall view, FIGS. 2 to 4 are partial views, and FIG. 5 is a view showing the external shape of the head. Patent applicant: Nippon Tungsten Co., Ltd. (and 1 other person)

Claims (1)

[Claims] 1. Ceramic spanners, wrenches, and similar tools thereof, characterized in that at least the head is formed of a ceramic sintered body containing partially stabilized ZrO_2 as a main component.