JPH04115866A - Burnishing tool for roller - Google Patents

Abstract

PURPOSE:To shorten the partcontacted with the face to be worked even in case of its shape being in a roller shape as the whole, by forming plural projection bars on the outer surface of the shaft like tool substrate in a circular section, and facing the side edge of at least one projection bar of those projection bars in the direction crossed with the bus along the circumferential direction of the tool substrate. CONSTITUTION:A high bearing is obtained, by contacting with the face to be worked with the projection bar 3 formed on the outer surface of a tool substrate 1, and the contact length becoming short with its being limited. When this tool substrate is rolled along the face to be worked in the radial direction, the projection bar causes a plastic deformation with its pressurizing the face to be worked, and burnishing finish is performed. In that case, either one projection bar is faced to the direction crossed with the bus along the circumferential direction of the tool substrate at its side edge part, so the part receiving a plastic deformation in the face to be worked is moved in the axial direction of the tool substrate, therefore the burnishing finish is performed, by rotating the tool substrate so that the rotation phase of the tool at the same place differs on each rolling of the tool repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a tool used for surface treatment, that is, burnishing, in which the outer surface of a workpiece is pressurized to cause plastic deformation.

Conventional technology Burnish processing is a type of processing method for improving the surface roughness and processing accuracy of the processed surface, and is known, for example, from Japanese Patent Application Laid-Open No. 1983-1989.
As described in Publication No. 62461, a tool having a hardness higher than that of the workpiece surface is pressed against the workpiece surface, and a deformation force exceeding the elastic limit of the workpiece surface is applied to only the shallow part below the workpiece surface. This is a processing method that causes plastic deformation. This method has the advantage of being able to perform precision finishing in a short time using simple equipment, and although work hardening is involved and the finished surface is smooth, it increases fatigue strength and therefore It is often used for finishing journal parts and bosses.

Problems to be Solved by the Invention Burnishing includes the finishing of the inner surface of a cylindrical part, and the finishing of the outer surface of a journal that receives radial loads and the end surface that receives thrust loads, but in most cases the former is finished. Ball-shaped tools are used, and tools such as rollers and balls are used for the latter finishing.

When a cylindrical tool such as a roller is used to burnish the outer surface of a workpiece, the tool comes into virtually line contact with the workpiece surface, increasing machining efficiency, but on the other hand, In order to sufficiently increase the contact pressure (contact pressure per unit length or unit area) on the machined surface, it is necessary to increase the total load applied to the tool, which may cause distortion of the workpiece or There is a problem that the device becomes larger. Furthermore, since it is difficult to increase the surface pressure, there is a disadvantage that finishing processing of highly hard workpieces is virtually impossible.

On the other hand, a ball-shaped tool substantially makes point contact with the workpiece, so a high surface pressure can be obtained even if the load applied to the tool is small, and the above-mentioned disadvantages do not occur. However, if you move a ball-shaped tool in one specific direction, you can essentially only process lines, so when using this type of tool, it is necessary to move the tool in at least two directions along the workpiece surface. It is necessary to do so. Further, when such a feed is applied to the tool, an axial force, for example, acts on the workpiece, and at the same time, a reaction force of the axial force acts on the tool.

As a result, the tool feed mechanism is required to have high rigidity and the ability to feed in at least two directions, making its configuration complex and requiring special jigs to hold the workpiece. There are problems, such as having to accept it as something. Furthermore, with a ball-shaped tool, when machining a corner where two surfaces intersect, interference occurs between the tool and one surface, resulting in an unprocessed portion with a width corresponding to the radius of the tool.

As described above, conventional tools are not always satisfactory in terms of machining efficiency and required equipment.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tool that can perform burnishing efficiently with a light load.

Means for Solving the Problems In order to achieve the above object, the present invention includes a plurality of protrusions formed on the outer surface of a shaft-shaped tool base with a circular cross section,
The side edge of at least one of these protrusions faces in a direction that intersects the generatrix along the circumferential direction of the tool base, and the shape of each protrusion extends in the axial direction of the tool base. The tool is characterized in that the total width of each protrusion is approximately the same at any position in the circumferential direction of the tool base.

Function: In the tool of the present invention, the protrusions formed on the outer surface of the tool base come into contact with the workpiece surface, and therefore the contact length is limited and shortened, so that high surface pressure can be obtained. When the tool base is moved along the surface to be machined in the radial direction, the protrusions pressurize the surface to be machined, causing plastic deformation and burnish finishing. In that case, since the side edge of one of the protrusions faces in a direction that intersects the generatrix along the circumferential direction of the tool base, the part of the workpiece surface that undergoes plastic deformation is on the tool base. By rotating the tool base so that the rotational phase of the tool at the same location differs each time the tool is repeatedly rolled, the entire width of the protrusion is burnished. Also, the total width of the protrusions in the axial direction of the tool base is
Since the rotational phase of the tool base is the same at all rotational phases, variations in surface pressure and load during machining are prevented, resulting in good finishing accuracy.

Example Next, the present invention will be explained based on examples.

FIG. 1 is a schematic perspective view showing one embodiment of the present invention, and FIG. 2 is a developed view showing the shape of the protrusion formed on the outer peripheral surface of the tool base 1. is formed in a cylindrical shape from a metal material such as high-speed steel, and a shaft portion 2 for rotatably holding with a jig (not shown) is formed at the center of both end faces thereof. A plurality of protrusions 3 are formed on the outer peripheral surface of this tool base. This protrusion 3 is
It directly contacts the surface to be burnished to apply a deforming force, and is formed along the helical direction of the outer peripheral surface of the tool base 1. A specific example is as shown in FIG. 2, where the tool base 1 is divided into four parts in the axial direction, and the protrusions 3 are arranged in each divided range so as to form an annular shape along the spiral direction.
is formed. The widths of these protrusions 3 are equal, and as shown in the developed view, the protrusions 3 on both ends in the axial direction are parallel to each other, and the protrusion 3 in the middle is opposite to the two protrusions 3. Therefore, the total width of each protrusion 3 in the axial direction of the tool base 1 is equal to They are the same.

Here, an example of a method for forming the above-mentioned protrusions 3 is to create the pattern shown in Fig. 2 in advance using a corrosion-resistant sheet, etc., and attach it to the outer peripheral surface of a cylindrical material that has been machined. However, it is possible to adopt a method of immersing this in a corrosive liquid to corrode and remove the parts other than the pattern to a predetermined depth, and then finishing by lapping.

The finishing process using the burnishing tool described above is performed by pressing the tool shown in FIG. 1 against the workpiece and rotating it, similar to the conventional burnishing process using a roller.

In that case, only the protrusions 3 are in direct contact with the workpiece surface, and their width is narrow, so the surface pressure on the workpiece surface is high.In other words, even if the total load applied to the tool is relatively small, It is possible to perform sufficient processing. Since the protrusions 3 are formed in a helical direction with respect to the tool base 1, as the tool base 1 is rotated, the position of contact with the workpiece surface changes in the axial direction, so that the tool base 1 can be repeatedly rotated. By rotating, the entire range corresponding to the length in the axial direction is processed. In that case, adjust the outer diameter of the tool base 1 so that the same location on the protrusion 3 does not constantly contact the same location on the work surface, that is, so that the rotational phase of the tool base 1 always changes with respect to the work surface. or adjust the rotation of the tool base 1. Furthermore, since the protrusions 3 are formed along the helical direction as described above, an axial force is generated for each protrusion 3 as the tool base 1 rotates, but in the example shown in the figure, a pair of protrusions Since the spiral direction of the strip 3 is opposite to the spiral direction of the other pair of protrusions 3, the axial forces generated in each protrusion 3 cancel each other out, and eventually the workpiece is axially No force is applied, and naturally no load is applied to the tool in the axial direction.

Therefore, according to the tool shown in FIG. 1, finishing processing can be performed by causing minute plastic deformation in a predetermined width range of the surface to be machined by rotating the tool continuously.

In addition, in the embodiment described above, an example was explained in which four protrusions of a constant width were formed, but the present invention is not limited to the above embodiment, and the width of the protrusion varies depending on the axis of the tool base. It is sufficient that the total measured in the direction is constant, and the width of each protrusion may vary along the way. Of course, the number is not limited to four. Further, in the present invention, it is sufficient to have a structure in which the machined part moves in the axial direction as the tool base rotates, and therefore the direction in which the protrusions are formed is not limited to the spiral direction with respect to the tool base.

As described in detail, according to the roller burnishing tool of the present invention, even though the tool is roller-shaped as a whole, the part that contacts the workpiece surface is shortened, so a large surface pressure can be applied to the workpiece surface with a small machining load. The machining area changes in the axial direction of the tool base as it rotates.
A wide range of processing is possible, and therefore, according to the tool of the present invention, burnishing can be performed efficiently with a light load. Furthermore, since the length or area in contact with the surface to be processed is always constant, highly accurate processing can be performed.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing one embodiment of the present invention, and FIG. 2 is a developed view showing the shape of the protrusion. 1... Tool base, 3... Projection. Applicant Toyota Motor Corporation Representative Patent Attorney Takeo Watanabe

Claims (1)

[Claims] A plurality of protrusions are formed on the outer surface of the shaft-shaped tool base with a circular cross section, and the side edge of at least one of the protrusions is aligned with the generatrix along the circumferential direction of the tool base. The protrusions are oriented in intersecting directions, and the shape of each protrusion is such that the total width of each protrusion measured in the axial direction of the tool base is approximately equal at any position in the circumferential direction of the tool base. A roller burnishing tool featuring: