RU2211132C1 - Grinding wheel head - Google Patents

Abstract

FIELD: machining of metals, grinding of parts with holes having elliptical cross-sections. SUBSTANCE: grinding wheel head includes grinding wheel with pneumatic drive and holder in the form of tube. The latter carries strip hinged to it with one end. Drive with grinding wheel is mounted for change of inclination angle of rotation axis of grinding wheel relative to axis of holder and is hinged to its opposite end. Tie-rod of circular cross feed of grinding wheel hinged with the use of bracket to frame of above-mentioned pneumatic drive is positioned in holder. EFFECT: expanded technological capabilities of grinding wheel head, raised precision and quality of machining. 1 cl, 5 dwg

Description

 The invention relates to mechanical engineering and metalworking by grinding and can be used in the manufacture of parts with holes with curved elliptical cross sections.

 Known spindle grinding head containing a grinding wheel installed in the holder, the axis of rotation of which is perpendicular to the central axis of the holder, coinciding with the plane of longitudinal symmetry of the grinding wheel, the holder is made in the form of a spindle, the axis of rotation of which coincides with its central axis [1].

 However, this head has limited technological capabilities and narrow specialization, namely, only for the treatment of external surfaces of double curvature. Its use for processing elliptical holes is difficult due to the presence of an open belt drive and its location on the outer surface of the holder. In addition, the inability to control the angle of inclination of the axis of rotation of the tool to the axis of rotation of the part makes it unsuitable for processing elliptical holes.

 Known grinding head for processing elliptical internal cavities, including a grinding wheel with a drive [2].

 The disadvantage of the head is the inability of the design to change the angle of inclination of the axis of rotation of the grinding wheel relative to the axis of the holder and its control, which limits its technological capabilities.

 The objective of the invention is the expansion of technological capabilities, improving the accuracy and quality of processing of the inner elliptical surface, reducing the roughness and solving the issue of the implementation of the infeed for repeated passes, as well as ensuring the independence of the profile of the processed product from the diameter of the grinding wheel.

 The task is achieved by the proposed grinding head, which serves for processing elliptical internal cavities, which includes a hollow tube tool holder with a pneumatic actuator, while it is equipped with a strap, at one end of which the pneumatic actuator is pivotally mounted with the tool, and the opposite end is pivotally fixed on the tool holder with the possibility of changing the angle of inclination of the axis of rotation of the tool relative to the axis of the holder.

 In addition, the grinding head is equipped with a circular lateral feed pneumatic drive rod located in the holder and pivotally connected to an arm that is mounted on the grinding wheel pneumatic drive housing.

 In FIG. 1 shows the proposed grinding head for machining holes with an elliptical surface; figure 2 presents a diagram of the finishing abrasive treatment of holes with an elliptical surface using the proposed head; figure 3 is a left view along A in figure 2; figure 4 is a diagram of the finishing abrasive machining of holes with an elliptical surface using the proposed head as much as possible worn circle; figure 5 is a left view along B in figure 4.

The grinding head is used to process elliptical internal surfaces, the operation of which is based on the fact that the projection of the circumference of the trajectory of the cutting surface of the tool on an inclined plane gives an ellipse [3]. Finishing abrasive treatment of a pre-bored hole is carried out by a rotating grinding wheel 1 with a longitudinal feed S _pr (Fig.2). The axis of rotation of the grinding spindle with a circle 1 is placed at an angle α to the axis of rotation of the workpiece 2. The angle α is determined by the formula:
α = arccos (b / a),
where a and b are the major and minor axes of the processed ellipse, respectively.

The circle 1 can be located on the spindle both parallel and inclined at an angle β to a plane perpendicular to the axis of rotation, and is mounted on the spindle by means of mounting flanges 3 with beveled ends and nuts. Stepless adjustment of the angle β of the inclination of the circle 1 is carried out by mutual rotation of the flanges 3, in which the beveled ends are made at an angle β _max / 2, and the rotation of one flange from one end to an angle relative to the axis should correspond to the rotation of the same angle of the other flange from the other end of the circle.

Before grinding begins with the new standard wheel, its peripheral cutting surface is corrected by dividing into two equal parts 4 and 5 the surface where the side part 5 works when the intersection of the axes of rotation of the part and the tool is to the right of the workpiece (according to FIG. 2 and 4) due to the longitudinal feed S _pr , the front end part 4 works when the intersection of the axes of rotation of the part and the tool is located in the workpiece or to the left of it. The outer diameter D of the new circle is 2a, i.e. the largest axis of the processed ellipse.

 The grinding head contains a tool holder 6 (Fig. 1), made in the form of a hollow pipe, on which the strap 7 is pivotally fixed at one end. The pneumatic actuator 8 with the tool 1 is pivotally mounted with the possibility of changing the angle of inclination α of the axis of rotation of the tool 1 relative to axis of the holder 6. In the hole of the holder 6 is a rod 9, pivotally connected to an arm 10, which is mounted on the housing of the pneumatic actuator 8. Also in the hole of the holder 6 is a pneumatic pipe 11 for supplying compressed air to the pneumatic vigatelyu 8.

When the rod 9 moves up or down, the angle α of the axis of rotation of the tool relative to the axis of the holder will change. Rod 9 is a thrust drive circular transverse feed S _α insertion (not shown in figure 1).

To remove the total allowance t left for grinding, a transverse feedrate S _{α of the} cut-in is necessary (Fig. 2), which is carried out in a circular motion around the axis of rotation of the tool, where the point of intersection of the axes of rotation of the part and the tool. The transverse feed S _α insertion is carried out by changing the angle α in the direction of reduction.

When the proposed head is operating, the infeed is carried out by moving the rod 9 down (according to FIG. 1), while the intersection of the axes of the tool and the holder moves to the left, therefore, to align the T. with the axis of the workpiece, it is necessary to adjust the position of the holder, which consists in shifting it to the right, i.e. movement - S _to . This movement can be carried out using known devices, for example, a support platform and a carriage, on which a holder is attached (see prototype). The movement of the rod 9 down and the movement of the holder to the right S _to should be carried out simultaneously. At the end of the workpiece, the circle and holder should return to their original position.

 As the abrasive wheel is worn out and its blunting is necessary, dressing is necessary, as a result of which the outer diameter decreases, therefore, to restore the outer diameter of the tool being machined, the circle is turned relative to the spindle, increasing its angle of inclination β to a plane perpendicular to the axis of rotation of the circle.

The maximum possible angle β _{max of} rotation of the circle relative to the spindle is equal to the angle α, while the diameter of the circle will be equal to 2b of the minor axis of the processed ellipse. With a smaller circle diameter, processing an ellipse of a given size is not possible. The remaining abrasive tool can be used to process smaller elliptical holes.

 The proposed grinding head for finishing abrasive machining of holes with an elliptical surface allows you to expand the technological capabilities of obtaining accurate elliptical curved surfaces and relates to the design of the tool, working by a carbon-free kinematic method. It allows you to increase the accuracy and quality of processing the inner elliptical surface, reduce the roughness and ensure the independence of the profile of the processed product from the diameter of the grinding wheel.

Sources of information
1. A.S. 1286398, MKI B 24 B 41/04. Spindle grinding head. Konshin A.S. and Reybach Yu.S. Application 3295043 / 25-08, application. 29.05.81, publ. 30.01.87, Bull. 4.

 2. A.S. USSR 384655, B 24 B 19/08, 03/27/1973 - prototype.

 3. Karelin N. M. Non-carbon machining of cylindrical parts with curvilinear cross sections. - M.: Mechanical Engineering, 1966, pp. 11-13, Fig. 10.

Claims (2)

 1. A grinding head for processing elliptical internal cavities, comprising a grinding wheel with a drive, characterized in that it is provided with a grinding wheel holder made in the form of a pipe and a bar pivotally fixed at one end to the holder, the pneumatic drive with a grinding wheel pivotally mounted at its opposite end with the possibility of changing the angle of inclination of the axis of rotation of the grinding wheel relative to the axis of the holder.  2. The grinding head according to claim 1, characterized in that it is equipped with a circular transverse feed of the grinding wheel located in the holder and an arm pivotally connected to it, fixed to the housing of the said pneumatic actuator.

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