JPH0353494B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a high-speed rotating component suitable for use as a rotating spindle of a machine tool such as an ultra-precision machine tool, an ultra-high-speed processing machine, or a high-rigidity machine tool. [Prior Art] The basic function of a machine tool is to produce workpieces with a desired geometric shape as precisely and efficiently as possible. It is fundamentally important to improve the static stiffness, dynamic stiffness, and thermal properties of rotating parts. Currently, for example, metallic materials such as carbon steel and Ni-Cr-Mo steel are used for spindles of machine tools, but these metallic materials have high density and coefficient of linear expansion, and have low elasticity. Since the coefficient is small, the amount of deformation due to cutting resistance, centrifugal force, processing heat, etc. is large, and in high-speed cutting, the natural frequency is low, and the occurrence of chatter vibration is unavoidable. For these reasons, current spindle materials have limitations in realizing high-performance machine tools. The same can be said of high-speed rotating parts other than the spindle. By the way, instead of conventional metal-based materials, carbon/carbon composites (hereinafter abbreviated as C/C composites), which are suitable as materials for high-speed rotating parts, are used to improve static, dynamic, and thermal properties. It is possible to achieve high rigidity, weight reduction, high damping performance, and low thermal deformation by improving the C/C composite, but it is difficult to process the C/C composite, and cutting and grinding it is difficult. During use, it is necessary to smooth the surface and improve hardness by filling voids near the surface, especially in areas that come into contact with other members. [Problems to be Solved by the Invention] The purpose of the present invention is to use a material for high-speed rotating parts.
The object of the present invention is to make it possible to use a C/C composite having properties suitable for this purpose, and in particular, to solve the problem of its workability and to improve its surface smoothness and hardness. [Means for Solving the Problems] In order to achieve the above object, the high-speed rotating component of the present invention has a C/C composite member surface that has a modulus of elasticity, a linear expansion coefficient, A desired shape is formed by coating high-hardness surface-forming materials with approximately the same coefficients through an intermediate material to increase bonding strength, and cutting, grinding, or polishing the coating layer. [Function] The C/C composite used as the material is a composite material that has high specific rigidity, specific strength, and vibration damping rate, and has a low coefficient of linear expansion and low density. Therefore, even during high-speed rotation, deformation due to centrifugal force and other external forces is extremely small, the dimensional stability is excellent, and the vibration damping ability is also large, so that a highly rigid high-speed rotating component can be realized. Heat deformation due to processing heat and bearing heat generation is also less likely to occur. Further, the intermediate material coated on the C/C composite fills the pores on the surface of the C/C composite and at the same time strengthens the bonding strength of the surface forming material. The surface of the surface forming material can be easily smoothed by cutting, grinding, or polishing, and the hardness of the surface can also be improved. [Effects of the Invention] According to the above-described high-speed rotating component of the present invention, the following effects can be expected. (1) The C/C composite used as the material has a coefficient of linear expansion less than 1/20 that of iron-based materials, so thermal deformation is extremely small. (2) The above C/C composite has a very low density, less than 1/4 of that of iron-based materials, and a large elastic modulus of more than 1.5 times, so deformation due to centrifugal force is small, and the critical speed is high, so high-speed rotation is not possible. It is possible. (3) C/C composites have excellent fatigue resistance, corrosion resistance, and heat resistance, are resistant to thermal shock, and can withstand use at high temperatures. (4) C/C composites have a high internal damping rate, so they have high vibration damping ability and can create high-speed rotating parts that are less prone to chatter vibrations. (5) The surface forming material is firmly fixed to the C/C composite via the intermediate material coated.
Since it can be processed relatively easily compared to C/C composites, it is possible to obtain high-speed rotating parts substantially made of C/C composites and processed into desired shapes. (6) The intermediary material fills the pores in the C/C composite and at the same time increases the bonding strength of the surface forming material,
By processing the surface forming material, the surface can be smoothed and the hardness can be improved. [Embodiment] FIG. 1 shows an embodiment in which the present invention is applied to a spindle for a machine tool. In Fig. 2, which shows a part of the spindle on an enlarged scale, 1 is a spindle material made of C/C composite. It will be done. The surface of the spindle material 1 is coated by plasma spraying, laser spraying, reaction diffusion method, etc.
An intermediate material 2 is formed by coating Mo, W, or Nb to a thickness of about several tens of micrometers, and a surface forming material 3 is coated on this intermediate material 2 by the same means. For the spindle material 1, it is effective to determine the fiber orientation in consideration of the cutting resistance and centrifugal force applied to the spindle in order to prevent deformation. Also,
The intermediate material 2 serves to fill the pores on the surface of the spindle material 1 and to bond the spindle material 1 and the surface forming material 3 with high strength. As the surface forming material 3, a material having almost the same elastic modulus and linear expansion coefficient as the C/C composite forming the material 1 and high hardness, such as WC.
- Using Co cermet, etc., it is coated to a thickness of several hundred μm, and the surface is cut into the desired shape and smoothness by ultra-precision cutting, grinding, and polishing, as shown by the chain line A in Figure 2. It will be finished. The coating and processing described above need not be applied to the entire surface of the spindle, but may be applied to at least the portion that comes into contact with other members. Although numeral 4 indicates a rolling bearing in the figure, the spindle can be supported not only by a rolling bearing but also by a sliding bearing, an air bearing, or the like. Table 1 shows the physical properties of the above C/C composite in comparison with those of conventionally used iron-based materials. From Table 1, it is clear that the C/C composite has a large elastic modulus and a small density and linear expansion coefficient when compared with iron-based materials. Therefore, in a spindle using the above C/C composite, the amount of deformation is extremely small even under the action of cutting resistance, centrifugal force, and other external forces, and the amount of thermal deformation is also small.

[Table] Next, an example of a prototype spindle for a machine tool manufactured by the present inventors will be described. When making a prototype spindle, a hollow cylindrical member with a stepped part as shown in FIG. 1 was made. As the C/C composite constituting the spindle material 1, a material molded with a 0°/90°/45° configuration was used.
On top of that, as an intermediate material 2, Mo was coated with a thickness of about 50 μm by plasma spraying, and further on top of that,
As the surface forming material 3, WC-Co cermet was coated to a thickness of 700 μm by low-pressure plasma spraying. Thereafter, ultra-precision cylindrical grinding was performed using a diamond wheel to finish the surface of the surface forming material 3 to form a bearing fitting part. Although the above description has been given to spindles for machine tools, the present invention can be applied to other high-speed rotating parts, and in that case, by changing the fiber orientation of the C/C composite, a more suitable It is possible to manufacture high-speed rotating parts.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the implementation of the present invention, and FIG. 2 is a partially enlarged sectional view thereof. 1... Spindle material, 2... Intermediate material, 3... Surface forming material.

Claims (1)

[Claims] 1. A high-hardness surface-forming material with approximately the same elastic coefficient and linear expansion coefficient as that of the carbon/carbon composite member is applied to at least the portion of the member surface that contacts other members via an intermediate material to increase bonding strength. A high-speed rotating part characterized by being coated and formed into a desired shape by cutting, grinding, or polishing the coating layer.