RU2239536C1 - Method of diamond-abrasive working and surface plastic deforming of openings - Google Patents

Abstract

FIELD: machine engineering, possibly abrasive finishing and surface plastic deforming of inner surfaces of openings of machine parts.

SUBSTANCE: method comprises steps of using combination type tool including diamond-abrasive portion in the form of tore-like elastic envelope with diamond-abrasive layer on outer surface and cylindrical housing with deforming members coaxial relative to tool. Deforming members are arranged in groove at mutual touching. Said groove is inclined by angle α relative to plane normal to tool axis. During working process effort for forcing diamond-abrasive portion to worked surface and value of arc contact are controlled. Method provided possibility for restoring outer diameter of worn disc due to supplying compressed air into elastic envelope.

EFFECT: enhanced efficiency, improved quality of working, increased useful life period of tool without readjustment due to restoration of outer diameter of worn abrasive disc during operation of tool.

3 cl, 6 dwg

Description

The invention relates to diamond abrasive metal processing by cutting and surface plastic deformation and can be used for finishing combined processing of the internal surfaces of the openings of machine parts.

A known method of abrasive machining with surface-plastic deformation of holes with a tool made in the form of a grinding wheel, on the peripheral surface of which intermittent non-working sections are formed, and a cylindrical body coaxially mounted with it with sections with deforming elements periodically located on its periphery, wherein each of the sections with deforming elements on a cylindrical body located opposite the discontinuous portion of the grinding wheel [1].

The disadvantage of this method and tool for its implementation is the impact treatment at the time of interruption of grinding and the beginning of the action of deforming elements due to the fact that the latter are installed on a slightly larger diameter than the grinding wheel, which causes a deterioration in quality and an increase in roughness of the treated surface. At the same time, as the grinding wheel wears out, its diametric size will decrease and stop processing. The restoration of the outer diameter, which is extremely necessary, is not provided, which dramatically reduces the duration of the tool and requires frequent readjustment.

As a prototype, a method is selected that is implemented by a combined tool for finishing holes, made in the form of a grinding wheel with a suction cone and coaxially mounted cylindrical body with deforming elements located at an angle α to the axis of the tool, the value of which is selected from the inequality 0 <α < arctg (H / D), where H and D are respectively the height and diameter of the grinding wheel, m; while on the periphery of the cylindrical body is made an annular groove located at a specified angle relative to the axis of the tool, and the deforming elements are placed in the groove from the condition of touching each other [2].

The disadvantage of this method and tool is the short-term performance and a long changeover time, because as the grinding wheel wears, its diametric size will decrease and stop processing. The restoration of the outer diameter, which is extremely necessary, is not provided, which dramatically reduces the duration of the tool and requires frequent readjustment.

The objective of the invention is to improve the quality of processing for even periodic, combined and sequential exposure of the abrasive and deforming elements to the machined surface with axially displaced cutting and deforming sections, as well as to increase the operating time without changes, productivity and tool life due to the increase in the length of the diamond contact arc - the abrasive part of the tool with the workpiece and restore the outer diameter of this part of the tool.

The task is achieved by the proposed method of diamond abrasive machining with surface-plastic deformation of the holes, implemented by a combined tool, which is made in the form of a diamond-abrasive part and coaxially mounted cylindrical body with deforming elements placed in the groove from the condition of touching each other and located under angle α to a plane perpendicular to the axis of the tool. Moreover, as a diamond-abrasive part, a toroidal elastic shell with a diamond-abrasive layer on the outer surface is used, while the force of pressing the diamond-abrasive part to the surface to be machined and the magnitude of the contact arc, as well as the restoration of the worn-out outer diameter of the diamond-abrasive part, are controlled by supply of compressed air to the elastic shell.

In addition, a toroidal elastic shell is used with ends made at an angle α to a plane perpendicular to the axis of the tool, with diamond-abrasive grains fixed on it using an elastic rubber bond.

Moreover, the angle α is selected from the inequality

α ≤ arctg (A _A / D),

where A _A is the oscillation amplitude of the diamond-abrasive part of the tool, the value of which is not more than the height B _{A of} this part, i.e.

A _A ≤ B _A ;

In _A - the height of the diamond-abrasive part of the tool;

D is the outer diameter of the tool.

Features of the method and the essence of the design of the combined tool for its implementation is illustrated by the drawings.

Figure 1 shows a diagram of the process of diamond abrasive processing and surface plastic deformation of the hole of the proposed method; figure 2 is a section aa in figure 1; figure 3 is a section bB in figure 2; figure 4 is a cross-section bb in figure 1, the outer diameters of the diamond-abrasive part and surface plastic deformation are the same and equal to D; figure 5 - section bb in figure 1, the outer diameter of the diamond-abrasive part is greater than (D _max ) the outer diameter (D) of the surface plastic deformation part, i.e. D _max> D, by increasing the pressure P _{compression channel;} figure 6 - scan tool track on the machined surface of the hole.

The proposed method of diamond abrasive processing with simultaneous surface-plastic deformation of the holes is implemented by a special combined tool.

The combined tool for finishing holes contains a diamond-abrasive part 1 and coaxially mounted cylindrical body 2 with deforming elements 3, which are located on a common shaft 4.

On the periphery of the housing 2, an annular groove 5 is made, located at an angle α to a plane perpendicular to the axis of the tool, in which the deforming elements 3 are placed so that they are in contact with each other.

The composition of the diamond-abrasive part 1 includes a toroidal elastic shell 6 with a diamond-abrasive layer 7 on the outer surface. The ends of the elastic shell 6 are made at an angle α to a plane perpendicular to the axis of the tool. The fastening of the diamond-abrasive grains of the layer 7 is performed using an elastic bond, for example, on a rubber basis.

A toroidal elastic shell 6 is mounted on the shaft 4 with a washer 8, an oblique washer 9 and secured with a nut 10.

Actuation of the operating state of a toroidal elastic shell 6 is performed by feeding through the shell side 11 and a central aperture 12 located on the shaft 4, and a fitting pin (not shown) under the pressure of compressed air P _{compression channel.}

The adjustment of the pressing force of the diamond-abrasive part 1 to the surface to be treated and the magnitude of the contact arc L, as well as the restoration of the worn-out outer diameter of the abrasive part 1 are also carried out by supplying compressed air to the elastic shell 6.

When excess compressed air is supplied to the elastic shell, the outer diameter (D _max ) of the diamond-abrasive part 1 becomes larger than the outer diameter (D) of the surface plastic deformation part, i.e. D _max > D, due to which the arc L of the contact of the tool with the machined surface increases.

The location of the diamond-abrasive part 1 of the tool at an angle α helps to reduce the temperature in the cutting zone and eliminates the formation of burns on the machining surface due to the axially offset diamond-abrasive cutting layer. The angle α is selected from the inequality

a≤ arctg (A _A / D),

where A _A is the oscillation amplitude of the diamond-abrasive part of the tool, the value of which is not more than the height B _{A of} this part, i.e.

A _A ≤ B _A ;

In _A - the height of the diamond-abrasive part of the tool;

D is the outer diameter of the tool.

The deforming elements 3, for example, in the form of needle rollers, are arranged so that they touch each other in the housing 2 in an annular groove 5, which is oriented to a plane perpendicular to the axis of rotation at an angle α, and is kept from falling out by two rings 13 behind the end necks 14.

The method implemented by this combined tool is as follows.

The product is clamped in the chuck of the grinding machine, and the tool in the spindle of the machine. The tool deforming elements 3 are brought into contact with the workpiece surface to be treated and give a certain interference, necessary for surface plastic deformation. In this case, the diamond-abrasive part 1 comes into contact with the surface to be treated, self-installs and removes a certain allowance, and the deforming elements 3 produce the final rolling of the treated surface.

Two processing modes can be distinguished by the proposed method:

- normal processing mode when the diameter (D _max ) of the diamond-abrasive part is equal to the outer diameter (D) of the surface plastic deformation part, i.e. D _max = D;

- intensive processing mode when the diameter (D _max ) of the diamond-abrasive part is larger than the outer diameter (D) of the surface plastic deformation part, i.e. D _max > D.

In the zone of combined diamond-abrasive processing and rolling (see figure 4), the process of plastic deformation is facilitated, since the microroughness formed by the abrasive has a high temperature and is easily deformed in the hot state. In addition, the simultaneous diamond abrasive processing and rolling in this zone reduces the roughness parameters of the resulting surface and reduces the wear of the diamond abrasive part 1.

Processing is completed by conventional rolling, where the final processing by plastic deformation takes place, which increases accuracy and reduces the geometric shape error of the hole being machined, compaction of the surface layer and increase of its hardness and wear resistance.

As noted above, in the annular groove 5 of the housing 2, needle rollers 3 are installed next to each other, some of which (no more than three) are between the workpiece and the housing 2 and, when rotated due to the frictional force, are rolled, deforming the surface layer of the part.

In this case, almost two rollers 3 participate in the work, providing continuity of the contact of plastic deformation.

To increase the durability period of the diamond-abrasive part of the tool, elbor, artificial and natural diamonds with a rubber bond are used as abrasive material, the thickness of the diamond-abrasive layer is 1 mm or more.

The tool, its elastic diamond abrasive part 1 under pressure P _{compression channel} compressed air adjacent to the surface with a force proportional to the pressure P _{compression channel,} increasing the contact arc length and thus intensifies processing.

The length of the arc L (see Fig. 5) of the contact increases due to an increase in the outer diameter D _{max of the} elastic diamond-abrasive part compared with the diameter D of the second part of the tool, which serves for surface plastic deformation.

Increasing the arc length L of the contact improves the quality of the surface layer and increases productivity.

The elastic diamond-abrasive part of the tool automatically takes the form corresponding to the shape of the surface being machined at the contact point [3, 4], allows radial movement of the diamond-abrasive layer during processing, restoring the outer diameter of the tool, while being a damper, smoothes out impacts and reduces vibrations.

The claimed technical solution allows to improve the quality and porosity of hole processing due to the periodic, combined and sequential exposure of the machined surface of the diamond-abrasive cutting layer and rolling with axially offset cutting and deforming sections.

It was experimentally established that during the finishing of holes on the ZK227V model grinding machine with the proposed tool under normal processing conditions, the required accuracy and surface roughness were achieved 1.9-2 times faster, the occurrence of burns on the treated surfaces was not recorded.

Thus, this method, based on a combination of two finishing processing methods, allows you to use the advantages inherent in these technological processes, to restore the outer diameter of the diamond-abrasive part of the tool, to regulate the force of pressing the diamond-abrasive part to the surface to be treated and the magnitude of the contact arc, and also to communicate cutting and deforming elements additional rectilinear translational movements not provided for by the kinematics of the machine, all this extends the technological e possible, shortens the main time that increases the performance and improves the quality of processing.

Sources of information

1. A. p. USSR 1296391, MKI B 24 D 5/00, 1987

2. RF patent 2103153, MKI B 24 D 5/00, B 24 B 39/00. Tool for finishing holes. Stepanov Yu.S., Afanasyev B.I. et al. 96101246/02, claimed 01/18/96, publ. 01/27/98 - a prototype.

3. RF patent 220077, MKI B 23 G 1/36, B 24 B 1/00. Method of abrasive processing of screws with a female tool. Stepanov Yu.S., Afanasyev B.I. et al. 2001117664/02, claimed 06/25/2001, publ. 03/10/2003.

4. French patent 2654027, MKI B 24 B 9/14. A surface treatment tool that automatically takes the appropriate shape. Claim 11/06/1989, publ. 10/05/1991. VINIPI number 19.

Claims (3)

1. The method of diamond abrasive processing with surface-plastic deformation of the holes, in which use a combined tool made in the form of a diamond-abrasive part and coaxially mounted cylindrical body with deforming elements placed in the groove from the condition of contact with each other located under angle α to a plane perpendicular to the axis of the tool, characterized in that as a diamond-abrasive part using a toroidal elastic shell with a diamond-abrasive layer on the outer th surface, wherein the pressing force control is carried diamond abrasive part surface to be treated and the size of contact arc, and the restoration of worn outer diameter of the diamond-abrasive portion by supplying compressed air to the elastic membrane. 2. The method according to claim 1, characterized in that they use a toroidal elastic shell with ends made at an angle α to a plane perpendicular to the axis of the tool, with diamond-abrasive grains fixed on it using an elastic rubber bond. 3. The method according to claim 1 or 2, characterized in that the angle α is selected from the inequality α ≤ arctg (A _A / D), where A _A is the oscillation amplitude of the diamond-abrasive part of the tool, the value of which is not more than the height B _{A of} this part, i.e. A _A ≤ B _A ; In _A - the height of the diamond-abrasive part of the tool; D is the outer diameter of the tool.

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