RU2202461C1 - Apparatus for polishing surfaces - Google Patents

Abstract

FIELD: machine tool manufacture, possibly subsidiary devices used for polishing any surfaces. SUBSTANCE: apparatus includes mandrel carrying abrasive wheel. Sleeve is mounted on mandrel. Said sleeve is inner race of roller radial needle bearing unit. Axes of outer and inner surfaces of sleeve are mutually inclined by angle α and they cross in symmetry center. Sleeve is placed between tapered washers whose end faces are mutually inclined by angle α. Abrasive wheel on flexible substrate is mounted on outer race of bearing and it is inclined by angle α relative to plane normal to rotation axis. In description of invention there is formula for determining value α.. Such design provides change of direction of traces of worked abrasive grain relative to previous traces and formation of trace grid and microgeometry similar to that formed at honing and grinding-honing at creation of vibrations. EFFECT: improved design providing enhanced efficiency and enlarged manufacturing possibilities. 4 cl, 6 dwg

Description

 The invention relates to the construction of auxiliary devices and accessories intended for use in the processing of any surfaces.

 A device for polishing surfaces, comprising a housing with a spindle bearing an abrasive wheel [1].

 The disadvantage of this device is not high productivity, narrow technological capabilities, namely for processing rotating parts, and the inability to change the direction of the trail of the processed abrasive grain in relation to the trace of the previous processing.

 A device for polishing surfaces is known, including a housing with a spindle bearing an abrasive wheel, and it is provided with a mandrel with guides perpendicular to the axis of the spindle for moving the housing, made spring-loaded relative to the mandrel and provided with a spring-loaded rod mounted parallel to the guides with the possibility of constant contact with the spindle, while the mandrel equipped with body travel limiters [2].

 The disadvantage of this device is low productivity and quality due to insufficient wheel speed, narrow technological capabilities, namely for processing rotating parts, and the inability to change the direction of the track of the processed abrasive grain relative to the track of the previous processing.

 The objective of the invention is to increase productivity and quality of processing, expanding technological capabilities and providing a change in direction of the trace of the processed abrasive grain in relation to the traces of the previous processing.

The problem is solved using the proposed device for polishing surfaces, including a mandrel bearing an abrasive wheel, and the mandrel is equipped with a sleeve that is the inner ring of a roller radial needle bearing, in which the axes of the outer and inner surfaces are made at an angle α and intersect in the center of symmetry with oblique washers , in which the ends are made at an angle α to each other, by an abrasive wheel, which is made on a flexible (rubber, rubber, volcanic, etc.) base and which is installed n on the outer ring of the bearing at an angle α to a plane perpendicular to the axis of rotation, while the angle α is determined by the formula
α <arcsin (B _to / D _to ), deg,
where B _to and D _to - respectively the height and outer diameter of the abrasive wheel, mm

 The device is equipped with a circular ring truncated at an angle α to a plane perpendicular to the axis of rotation, mounted on the end of the circle coaxially to the axis of the mandrel and a two-arm lever, pivotally in an arm mounted on the mandrel, with one arm in contact with the inner surface of the ring, the other arm provided with a screw screwed into the mandrel , and depreciation spring.

In addition, the mandrel is installed at a distance H from the surface to be machined and rotates with a frequency of No, respectively determined by the formulas:
H = 0.5 [(D $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ + B $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ ) ^1/2 ] -B _to tgα, mm,
N _o ≥N _d [2πD _k / L _max ], min ^-1 ,
where N _d is the rotational speed of the part, min ^-1 ;
L _max - maximum arc of contact between the circle and the part, mm.

Figure 1 shows the proposed device, a General view, a longitudinal section; in FIG. 2 - section BB in figure 1; figure 3 is a section GG in figure 1; figure 4 is a General view of the device, the circle is rotated 90 ^o with respect to figure 1, view along E in figure 1; figure 5 is a section FJ in figure 4; Fig.6 is a diagram for calculating the distance H from the axis of the mandrel to the workpiece.

 A device for polishing both rotating and non-rotating surfaces comprises a mandrel 1 bearing an abrasive wheel 2, which is provided with a sleeve 3, which is the inner ring of the bearing 4, for example, a radial needle roller bearing, which allows to reduce radial dimensions, to ensure a long service life and perceive as radial axial loads.

 The axis of the outer and inner surfaces of the sleeve 3 are made at an angle α and intersect at the center of symmetry. The sleeve 3 is mounted on the mandrel 1 between the oblique washers 5 using nuts 6. The ends of the oblique washers 5 are made at an angle α to each other.

The abrasive wheel 2 is made on a flexible, for example, rubber, rubber, vulcanizer, etc. basis and mounted on the outer ring of the bearing 4 at an angle α to the plane perpendicular to the axis of rotation, while the angle α is determined by the formula:
α <arcsin (V _to / D _to ), deg,
where In _to and D _to - respectively, the height and outer diameter of the abrasive wheel, mm

 In this case, the axis of the peripheral cutting cylindrical surface of the circle and its holes coincide.

 The proposed device is equipped with a circular ring 7 truncated at an angle α to a plane perpendicular to the axis of rotation, mounted on the end of the circle 2 coaxially to the axis of the mandrel 1, and a two-arm lever 8, pivotally mounted on the axis 9 in the bracket 10 on the mandrel 1.

 With one shoulder, the lever 8 is in contact with the inner surface of the ring 7, the other shoulder is equipped with a screw 11, which is screwed into the mandrel 1, and is tightened by the damping spring 12.

For the effective operation of the device, the axis of the mandrel 1 is installed at a distance H from the work surface, which is less than the radius of the circle, and is determined from the following considerations. The arrow h of the segment of contact of the circle and the part (Fig.3 and 6) with a sufficient degree of accuracy is equal to
h≅B _to tgα.
The diagonal diameter ab is
ab = (D _to ² + B _to ² ) ^1/2 .

Wherein
H = 0.5ab-h.

Substituting the values of ab and h, we obtain the formula for calculating the distance from the axis of the mandrel to the workpiece
H = 0.5 [(D $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ + B $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ ) ^1/2 ] -B _to tgα, mm.
At a distance that is less than the radius of the circle, equal to D _to / 2, the peripheral part of the circle will cover the surface of the part, as can be seen in FIG. 3 and 5. The length of the setting arc L, i.e. The contact of the circle and the part for different cross sections of the circle is different and depends on the angle of inclination of the circle and its diameter. It varies from L = 0 (figure 2) at the left end, according to figure 1, to L _max (figure 3) - at the right end and is determined by the formula [3]:
L _max ≅0.0174 (ab / 2) β, mm,
where β is the central angle of the arc of contact between the circle and the part, deg.

При прохождении кругом нулевого угла наклона (фиг.4) длина дуги контакта L_cp (фиг.5) будет меньше L_max и определяется по формуле:
L_ср≅0,0174D_кarccos[1-2(B_кtgα)/(D $\genfrac{}{}{0ex}{}{\text{2}}{\text{к}}$ +B $\genfrac{}{}{0ex}{}{\text{2}}{\text{к}}$ )^1/2], мм.
Как видно из конструкции, устройство работает в двух режимах:
- режим работы без проскальзывания круга относительно детали;
- режим работы с проскальзыванием круга относительно обрабатываемой поверхности детали.The angle β is determined from the formula h = (1-cosβ / 2) ab / 2 [3], with the substitution of all the values found above:
β = 2arccos [1-2 (B _to tgα) / (D $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ + B $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ ) ^1/2 ], deg.
Substituting the value of ab found above, we define

When the circle passes through a zero angle of inclination (figure 4), the length of the contact arc L _cp (figure 5) will be less than L _max and is determined by the formula:
L _cf ≅0.0174D _to arccos [1-2 (B _to tgα) / (D $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ + B $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ ) ^1/2 ], mm.
As can be seen from the design, the device operates in two modes:
- mode of operation without slipping the circle relative to the part;
- mode of operation with slipping circle relative to the workpiece surface.

 In the mode without slipping the circle relative to the part, the device operates as follows.

 When the part rotates, circle 2 receives rotational motion from its outer surface due to friction forces.

Due to the inclination of the circle 2, its free rotation on the bearing 4 and the forced rotation of the sleeve 3 with an angular displacement, the frequency of rotation of the circle 2 will be determined by the speed of the workpiece, i.e. the part will lead a circle
V _d = V _k
in this case, the abrasive grain located on the peripheral cutting part of the wheel, in contact with the part, will perform cutting during its longitudinal movement along the surface to be treated and leave longitudinal risks, as can be seen in Fig. 1.

 For effective cutting in this longitudinal direction, it is necessary to comply with the condition under which for half a turn of the mandrel 1 circle 2, making an oscillatory movement in one direction, for example, from left to right, or from right to left, its peripheral cutting abrasive grain will be in the zone of the contact arc L .

Denote by T _about - the time of the longitudinal movement of the abrasive grain located in the zone of the contact arc, depending on the speed and frequency of rotation of the mandrel, which is determined by the formula:
T ₀ = 0.5 N ₀ , min,
where N _o - the rotation frequency of the mandrel, min ^-1 .

The rotation time of the part T _d by the value of the contact arc L _max is determined by the formula:
T _d = L _max / (N _d πD _k ), min
where N _d is the rotational speed of the part, min ^-1 .

To comply with the above condition, equality is necessary
T _about = T _d , min.

Substituting the found values and simplifying, we obtain the formula for the ratio of the rotational speeds of the part and the mandrel for effective polishing:
N _o ≥N _d [2πD _c / L _max ], min ^-1 .
In the second mode - the mode of operation with the slip of the circle relative to the workpiece surface, the device operates as follows.

 When the part rotates, circle 2 receives rotational motion from its outer surface due to friction forces. The lever 8, one shoulder (for example, the left, according to figure 1), being in contact with the inner surface of the ring 7, with the force provided by the screw 11, accelerates or slows down the rotation of the circle 2, thereby creating in the treatment area due to slippage of the treated surface details relative to the working surface of the rotating circle 2 transverse grinding condition.

 If the first mode without slipping leaves longitudinal risks on the machined surface of the part (see Fig. 1), then the second mode with slipping leaves risks inclined to the axis of rotation on the machined surface (see Fig. 4). When working in the second, more efficient mode, the transverse rotational movement of the circle obtained from the mandrel is superimposed on the longitudinal movement of the abrasive grain.

 If the speed of the mandrel is greater than the frequency of rotation of the circle, which he receives from the part, then the frequency of rotation of the circle in the second mode is accelerated and vice versa, if the frequency of rotation of the mandrel is less than the frequency of rotation of the circle, which he receives from the part during his free rotation, then the frequency of rotation of the circle is slowed down . Slowing down and accelerating the circle in the second mode does not affect the direction of the marks, they will be inclined to the axis of rotation of the part.

 Slowing the rotation of the wheel will increase the processing time and lower productivity compared to accelerating the wheel.

 Grinding along the entire length of the machined surface is carried out by longitudinal movement of the device.

 The method implemented by the proposed device for polishing surfaces can be attributed to grinding honing [4]. A feature of grinding honing is an intermittent path contour due to the alternation of grains in contact with the workpiece. Thanks to the local contact zone and the change of the cutting grains of the wheel, the heat balance of the tool improves, its resistance increases and salinity decreases, and the large length of the surface of the circle, tens of times greater than the length of segmented honing bars, allows it to increase its resistance by the same amount. The free supply of cutting fluid to the treatment zone also improves grinding performance.

 The use of the device and the grinding method implemented with its help is a promising process, because allows you to several times increase the cutting speed compared with the speed of traditional grinding methods.

 The proposed device for processing cylindrical surfaces is installed on conventional circular and intra-grinding machines, for processing flat surfaces - on surface grinding machines, while the device improves productivity and processing quality, expands technological capabilities and provides changes in the direction of the track of the processed abrasive grain relative to the traces of the previous processing , determining the trace network and the nature of microgeometry as in honing, grinding with superposition of vi radios.

 The advantage of the device is the use of a conventional standard tool, as well as the ability to control the angle of inclination of the circle, which makes it easy to optimize the processing process in a production environment when changing the material being processed, chemical-thermal operation, cutting tool, technical conditions, and cutting conditions.

Sources of information
1. Reference technologist mechanical engineer. In 2 volumes T. 2 / Under the general. ed. A.N. Malova. - M.: Mechanical Engineering, 1963. P.526 - analogue.

 2. A. p. USSR 622647, MKI V 24 V 5/02. Device for polishing surfaces. B. M. Nikiforov and R. P. Chauzov. Application 2150282 / 25-08, pending. 07/01/75, publ. 09/05/78. Bull. 33 is a prototype.

 3. Bronstein I.N., Semendyaev K.A. Math reference for engineers and students of technical colleges. - 13th ed., Revised. - M.: Science, Ch. ed. Phys.-Math. lit., 1986.P. 185.

 4. Ermakov Yu.M., Stepanov Yu.S. Current trends in the development of abrasive processing. (Mashinstr. Pr-in. Ser. Technology and equipment. Metal processing by cutting: Review. Inform. / VNIITEMR. Issue 3) - M., 1991. S. 24-26.

Claims (4)

1. A device for polishing surfaces containing a mandrel bearing an abrasive wheel, characterized in that the mandrel is provided with a sleeve, which is the inner ring of a roller radial needle bearing, and the axis of the outer and inner surfaces of which are located at an angle α with their intersection in the center of symmetry of the sleeve, oblique washers with ends at an angle α to each other, and the abrasive wheel is made on a flexible basis and mounted on the outer ring of the said bearing at an angle α to a plane perpendicular to the axis of rotation of the frames ki, while the angle α is determined by the formula
α <arcsin (B _to / D _to ), deg,
where In _to and D _to - respectively, the height and outer diameter of the abrasive wheel.  2. The device according to claim 1, characterized in that it is equipped with a truncated angle α to a plane perpendicular to the axis of rotation of the mandrel, a circular ring mounted on the end of the circle coaxially to the axis of the mandrel, and a two-arm lever pivotally mounted in the bracket on the mandrel and in contact with one shoulder with the inner surface of the ring, while the other shoulder is equipped with a screw screwed into the mandrel with a damping spring. 3. The device according to claim 1 or 2, characterized in that the mandrel is installed at a distance N from the surface to be machined with the possibility of rotation with a frequency of N _o , while the values of H and N _{o are} determined by
H = 0.5 [(D $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ + B $\genfrac{}{}{0ex}{}{\text{2}}{\text{to}}$ ) ^1/2 ] -B _to tgα, mm,
N _o ≥N _d [2πD _k / L _max ], min ^-1 ,
where N _d is the rotational speed of the part, min ^-1 ;
L _max - maximum arc of contact between the circle and the part, mm.  4. The device according to any one of claims 1 to 3, characterized in that a rubber, rubber, vulcanite base is used as a flexible base of the abrasive wheel.

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