RU2253559C1 - Machine tool for centerless super-finish working of cylindrical articles - Google Patents

Abstract

FIELD: machine engineering, possibly centerless super-finish working of cylindrical articles.

SUBSTANCE: machine tool includes two rolls for positioning articles and for moving them. Rolls are mutually spaced and are mounted by inclination angle λ of crossing their axes. Value of angle λ may be determined as sum of values of λ₁ and λ₂ of turning angles of first and second rolls relative to motion direction of articles; λ₁ ≠ λ_2.

EFFECT: enlarged manufacturing possibilities of machine tool, enhanced quality of worked articles.

2 cl, 2 dwg

Description

The machine is intended for grinding surfaces of products, in particular, for centerless superfinishing surfaces of cylindrical products.

For the final surface treatment of products in mass production, centerless superfinishing machines have been widely used. The main part of such machines are roll devices, which simultaneously perform transport and shaping functions. Roller devices position products relative to the bars of superfinishing stations and move them along the entire processing length (see Mazalsky V.N. Superfinishing machines. - L .: Mashinostroenie, 1988. - P.80). To ensure the accuracy of processing, the trajectory of movement of cylindrical products should be rectilinear and parallel to the plane of oscillation of the bars of the super-finishing stations of the machine.

Known centerless superfinishing machines contain roll devices, including two rolls, rotated relative to each other at an angle of 2λ and installed at a distance of 2ν (see Mazalsky V.N. Superfinishing machines. - L .: Engineering, 1988. - P. 62) . Such roll devices are produced in two types: with a constant roll turning angle and the possibility of adjusting the center distance; with the possibility of simultaneous adjustment of the crossing angle and the interaxal distance of the rolls. In both cases, each of the rolls is turned relative to the direction of movement of the workpiece by angle λ.

In centerless superfinishing machines, rolls of various shapes are used, for example, in the form of a single-cavity rotation hyperboloid with a symmetric and asymmetric profile (see Gundorin V.D., Ryazanov A.V. Form of transporting rolls for centerless superfinishing of cylindrical parts // Finishing of machine parts: Interuniversity scientific scientific collection - Saratov, 1975 .-- P.7-13). This form of rolls does not take into account the principle of mutual bending of the surfaces of products and rolls with their relative movement. Therefore, the trajectory of the movement of products on such rolls differs from straightforward, which reduces the accuracy of processing.

Another known form of rolls of centerless superfinishing machines is asymmetric curvilinear, close to a single-cavity hyperboloid of rotation (see Mazalsky V.N. Superfinishing machines. - L.: Mechanical Engineering, 1988. - P.84). The disadvantage of a machine with this form of rolls is the error of the trajectory of movement of products along the rolls in horizontal and vertical planes. This fact leads to the occurrence of deviations in the shape of the products in the form of barrel-shaped, saddle-shaped or conical.

By the set of similar essential features, the closest technical solution to the claimed device can be selected, for example, a machine for centerless superfinishing of cylindrical products according to patent RU No. 2212994, 24 V 35/00, 1/00. The known machine tool contains two rolls for positioning and moving workpieces installed at a distance of 2ν from each other and at an angle of 2λ crossing their axes. In this case, each of the rolls is deployed relative to the direction of movement of the products by an angle λ in opposite directions, which creates an angle 2λ of intersection of the rolls relative to each other. To ensure a rectilinear trajectory of movement of products during processing, the outer surfaces of the rolls are made in the form of a non-linear quasi-hyperboloid of revolution, determined by the given dependencies.

The known machine for centerless superfinishing of cylindrical products has the following disadvantages. The symmetry of the location of the rolls in the angle of rotation X relative to the direction of movement of the products determines the limited capabilities of the machine during commissioning.

The profile of the rolls in a symmetrical arrangement, calculated according to the known dependencies, has a large difference in diameters in different sections along the processing length. As you know, the coefficient of friction depends on the speed of the relative movement of the contacting surfaces, which in turn is determined by the circular speed and radius of the rolls. Therefore, with a significant difference in the diameters of the rolls, one of them is the leading one, and slippage occurs on the other, which causes the appearance of longitudinal patterns on the products and, ultimately, reduces the quality of processing.

The objective of the present invention is to expand the technological capabilities of the machine and improve the quality of the processed products with centerless superfinishing.

The problem is solved by the fact that the proposed machine for centerless superfinishing of cylindrical products, containing two rolls for their positioning and movement, installed at a distance of 2ν from each other and at an angle λ of crossing their axes.

New in the proposed method is that λ = λ ₁ −λ ₂ , where λ ₁ and λ ₂ are the rotation angles of the first and second rolls relative to the direction of movement of the products, and λ ₁ ≠ λ ₂ .

New in the proposed method is also that the outer surfaces of the rolls are characterized by the dependencies:

for roll with angle λ ₁

for roll with angle λ ₂

where x _Bi , y _Bi, z _Bi - coordinates of the surface of the roll, mm;

r is the radius of the workpiece, mm;

λ ₁ ; λ ₂ - the angles of intersection of the axes of the first and second rolls and the direction of movement of the products, respectively, deg;

_i - угол контакта валка и изделия, град;

_i is the contact angle of the roll and the product, deg;

h, ν - adjustment coordinates of the super-finishing machine, mm.

The technical result of the claimed invention is to improve the quality of processing and expand the technological capabilities of the machine with a centerless superfinishing of cylindrical products.

Figure 1 presents the coordinate diagram of the rolls on the machine, figure 2 - the calculated axial profile of the rolls.

The calculated dependences for determining the outer surface of the rolls are obtained on the basis of the theoretical principles of the theory of envelopes in space.

In Fig.1: S ₀ (X ₀ , Y ₀ , Z ₀ ) - coordinate system of the product; S ₁ (X ₁ , Y ₁ , Z ₁ ) - the coordinate system of the roll with an angle of inclination λ ₁ ; S ₂ (X ₂ , Y ₂ , Z ₂ ) - the coordinate system of the roll with an angle of inclination λ ₂ . The coordinate systems S ₁ and S _{2 are} defined in the coordinate system S _{0 by a} vertical adjustment offset along the X ₀ axis by h, a horizontal adjustment offset along the Y ₀ axis by ± ν and a counterclockwise rotation by the angles λ ₁ and λ _2, respectively . For the convenience of perception in figure 1 rolls are conditionally not shown.

To find the outer surface of the rolls, it is necessary to move the surface of the cylindrical product described in the coordinate system S ₀ to the coordinate systems of the rolls S ₁ and S _2, respectively. The condition for the mutual bending of the surfaces of the rolls and the product during their relative movement is the intersection of the normals to the surface of the product with the axis of the rolls.

The outer surfaces of the rolls are calculated according to the dependencies:

for roll with angle λ ₁

for roll with angle λ ₂

where x _Bi , Y _Bi, z _Bi - coordinates of the surface of the roll, mm;

r is the radius of the workpiece, mm;

λ ₁ ; λ ₂ - the angles of intersection of the axes of the first and second rolls and the direction of movement of the products, respectively, deg;

_i - угол контакта валка и изделия, град;

_i is the contact angle of the roll and the product, deg;

h, ν - adjustment coordinates of the super-finishing machine, mm.

The rolls thus calculated have a different shape of the outer surface depending on the magnitude of the angles λ ₁ and λ ₂ .

Figure 2 shows an example of the axial profile of the rolls, calculated for the following initial parameters: r = 20.0 mm; λ ₁ = 1 °; λ ₂ = 3 °; ν = 80.0 mm; h = 20.2 mm.

Claims (2)

1. Machine for centerless superfinishing of cylindrical products, containing two rolls for their positioning and movement, installed at a distance of 2ν from each other and at an angle λ of intersection of their axes, characterized in that λ = λ ₁ + λ ₂ , where λ ₁ and λ ₂ - respectively, the rotation angles of the first and second rolls relative to the direction of movement of the products, with λ ₁ ≠ λ ₂ . 2. The machine according to claim 1, characterized in that the outer surfaces of the rolls are characterized by dependencies for roll with angle λ ₁

for roll with angle λ ₂

where x _Bj , y _Bj z _Bj - coordinates of the surface of the roll, mm; r is the radius of the workpiece, mm; λ ₁ , λ ₂ - the angles of intersection of the axes of the first and second rolls and the direction of movement of the products, respectively, deg; ϑ _i is the contact angle of the roll and the product, deg; h, ν - adjustment coordinates of the super-finishing machine, mm.

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