RU177993U1 - Honing head - Google Patents

Abstract

The utility model relates to mechanical engineering technology, to metal cutting, in particular to honing heads for the final processing of precision holes. The technical result is achieved by a honing head containing a housing, bearing pads with abrasive bars fixed by return springs, made with end surfaces at an angle of 2-6 degrees to the radius of the honing head and installed in the housing to ensure simultaneous axial and radial movement of the bearing blocks along the mating guide surfaces of the housing installed in the stepped recess of the housing expanding element in contact with the bases of the bearing blocks, made in the form of a sleeve of elastomeric material, and a two-stage piston located at a small step in the bore of the sleeve. The technical result is to increase the accuracy of the form with increased surface quality of the machined hole with maximum productivity.

Description

The utility model relates to mechanical engineering technology, to metal cutting, in particular to honing heads for the final processing of precision holes.

A device is known for a multi-row honing head comprising a housing carrying pads with abrasive blocks, expandable elements mounted to interact with blocks of bars, an expandable rod and an independent mechanism for regulating and fixing each row of bars, the housing being made in the form of a set of clips installed with the possibility of axial movement on the outer cylindrical surface. Axial movement of the bars is carried out before processing and is necessary for the convenience of regulating the position of each row of abrasive bars [Copyright certificate SU No. 1220757, B24B 33/08, 1986].

The device is characterized by limited opportunities to improve the quality of the treated surface, since it does not exclude the possibility of cutting grain getting into a risk scratch previously cut by it, and, accordingly, the presence of deep scratches on the treated surface, and the device has a complex mechanism of preloading which does not ensure the alignment of the blocks of blocks when concentrated application of force to them, which leads to limited accuracy in the shape of the treated surface.

A known honing head comprising a housing with pusher sectors installed in it, designed for each of them to interact with expanding cones on the one hand, and with bar holders with abrasive bars made in the form of at least two helical cylindrical compression springs located at an angle to the forming head and pressed end faces to each other with Belleville springs [Patent RU 2146594, B24B 33/08, 2000].

The device is characterized by limited capabilities to ensure high accuracy of the form during the finish processing of holes due to the complex multi-link mechanism of pressing blocks with bars to the surface to be treated and does not exclude the possibility of cutting grain getting into the scratch risk cut by it.

Known honing head, which contains a housing carrying pads with abrasive blocks, expandable elements installed with the possibility of interaction with blocks of blocks, an expanding rod and an axial movement mechanism of abrasive blocks, made in the form of a glass, in the radial holes of which on the axes are mounted to rotate around axes are rotary strips, one end of which goes into the grooves of the block, and the other into the grooves of the expansion rod and the axial movement of the blocks with bars up when moving the expansion rod from [Patent RU 2108902, B24B 33/08, 1996].

The device is characterized by limited capabilities to ensure high accuracy of shape and performance when finishing holes due to the complex multi-link mechanism for pressing blocks with abrasive bars to the surface to be processed and concentrated application of load at two points of the block and the inability to increase the number of coaxially arranged blocks with bars to increase productivity.

A known honing head comprising a housing carrying pads with abrasive blocks, expandable elements mounted to interact with blocks of blocks, an expanding rod, an axial and radial movement mechanism of abrasive bars, made in the form of a packet of cone-shaped disk-shaped springs with cone angle 5-14 degrees installed between the step of the expanding rod and the housing, and return springs [Patent RU 168775, B24B 33/08, 2017].

The disadvantage of this device is the presence of a large number of contacts of a packet of Belleville springs along the length of the blocks of bars, which leads to uneven distribution of the compressive force between them. The uneven distribution of the preload force reduces the accuracy of the shape of the hole being machined.

Known honing head containing a housing, a bearing element in the form of a corrugated shell, on the outer surface of which abrasive bars are fixed, and a cylinder with radial holes mounted in the housing inside the corrugated shell, while all the cavities formed are filled with hydroplastic, and the end surfaces of the corrugated shell are located at an angle of inclination of 2-6 degrees to the radius of the honing head, corresponding to the angle of inclination of the inner guide surfaces of the housing. The expanding rod is made in the form of a stepped piston installed with the possibility of impact on the hydroplastic [Patent RU 171783, B24B 33/08, 2017].

The disadvantage of this device is the low stiffness of the thin corrugated shell in the radial direction, and when the pressure of the hydroplastic is deflected along with the abrasive bars, which will reduce the accuracy of the shape of the hole being machined. In addition, the presence of the axial component of the force will lead to uneven friction on the inclined guides of different ends, which will also lead to a decrease in the accuracy of the machined hole.

The closest technical solution is a honing head containing a housing, bearing pads with abrasive bars fixed by return springs, made with end surfaces at an angle of 2-6 degrees to the radius of the honing head and installed in the housing to ensure simultaneous axial and radial movement of the bearing pads along the guide rails to the surfaces of the housing, an expandable element made in the form of hydroplastic in contact with the bases of the bearing blocks. The expanding rod is made with a plunger installed with the possibility of impact on the hydroplastic [Patent RU 169719, B24B 33/08, 2017].

The disadvantage of this device is the uneven distribution of pressure of the hydroplastic along the honing head from the plunger. This will lead to uneven distribution of load on the bearing pads along the length. This will lead to jamming of the movement of the bearing blocks along the mating guide surfaces of the housing and reduce the accuracy of the shape of the machined hole.

The task is to develop the design of the honing head with a simple mechanism for compressing the blocks with abrasive blocks, providing radial and axial movement, a central application of force to the blocks, with a coaxial arrangement, with the possibility of maximizing their number.

The technical result is to increase the accuracy of the form with increased surface quality of the machined hole with maximum productivity.

The technical result is achieved by a honing head containing a housing, bearing pads with abrasive bars fixed by return springs, made with end surfaces at an angle of 2-6 degrees to the radius of the honing head and installed in the housing to ensure simultaneous axial and radial movement of the bearing blocks along the mating guide surfaces of the housing , expandable element in contact with the bases of the bearing pads, and a rod mounted with the possibility of impact on the expandable element, p In this case, the expanding element is made in the form of a sleeve of elastomeric material installed in a stepped recess of the housing, and the rod is made in the form of a two-stage piston and is located at a small step in the bore of the sleeve.

The essence of the technical solution lies in the fact that when the axial movement downward of a two-stage piston located at a small step in the bore of the sleeve of elastomeric material, its large stage acts on the end face of the expandable element made in the form of a sleeve of elastomeric material. The other end of the sleeve is installed in a stepped recess of the housing. Under the action of a two-stage piston, the sleeve is deformed in the axial direction and acts on the base of the bearing blocks, moving the bearing blocks in the radial direction. Moreover, the implementation of the bearing blocks with end surfaces at an angle of 2-6 degrees to the radius of the honing head, provides simultaneously with the radial and axial movement of the bearing blocks along the mating guide surfaces of the housing.

The radial arrangement of the bearing pads with abrasive blocks allows the installation of the maximum number of bearing pads with abrasive blocks, which helps to increase the productivity of the hole. This ensures a uniformly distributed application of radial load, which ensures the accuracy of the shape of the machined cylindrical hole and improves the quality of its surface. The axial movement of the blocks eliminates the appearance of deep grooves and improves surface quality.

The essence of the design of the honing head is illustrated by figures.

In FIG. 1 shows a longitudinal section through a honing head.

In FIG. 2 shows a cross section AA of a honing head.

и шириной b) с абразивными брусками 4 с возможностью их свободного радиального (S_R) и осевого перемещения (S_O). Шток хонинговальной головки выполнен в виде двухступенчатого поршня 5.The honing head comprises a housing 1, in radial slots 2, of which bearing blocks 3 are installed (length

and a width b) with abrasive bars 4 with the possibility of their free radial (S _R ) and axial movement (S _O ). The stem of the honing head is made in the form of a two-stage piston 5.

The end surfaces 6 of the bearing blocks 3 are made at an angle of 2-6 degrees to the radius of the honing head and are installed in the housing with simultaneous axial and radial movement of the bearing blocks 3 along the mating guide surfaces 7 of the housing 1.

An expanding element made in the form of a sleeve 9 of elastomeric material (with an outer diameter D) installed in a stepped recess 10 of the housing 1 contacts the bases 8 of the bearing blocks 3.

The two-stage piston 5 is installed so that its small stage 11 (with diameter d) is located in the hole of the sleeve 9, and the large stage 12 is in contact with the end face of the sleeve 9.

The return springs 13 are designed to return the bearing pads 3 to its original position after lifting the two-stage piston 5.

The device operates as follows.

After the honing head is inserted into the hole to be machined, its rotation and reciprocating motion are turned on, after which the radial and axial movement mechanism that radially (S _R ) and axially moves (S _O ) the bearing blocks 3 with abrasive bars 4 comes into play. After each double-stroke honing head, under the action of a two-stage piston 5 (moves along the axis of the honing head down a certain value S _P ) the walls of the sleeve 9 are deformed in the axial direction and act basically 8 bearing blocks 3, moving the bearing blocks 3 in the radial direction (S _R ). The bearing blocks 3 are moved with the abrasive blocks 4 in the radial direction and dosed feed S _{R of the} abrasive blocks 4 is carried out.

You can determine the axial displacement S _{P of the} expansion rod 5 to achieve the radial feed S _R according to the formula:

,

,

where S _R is the radial feed of the carrier blocks 3 with abrasive bars 4;

S _O - axial movement of the bearing blocks 3 with abrasive bars 4;

α is the angle of inclination of the end surfaces 6 of the bearing blocks 3 to the radial direction of the honing head.

n is the number of bearing blocks 3;

- длина несущих колодок 3;

- the length of the bearing blocks 3;

b is the width of the bearing blocks 3;

D is the outer diameter of the sleeve 9 of elastomeric material;

d is the inner diameter of the sleeve 9 of elastomeric material;

We calculate the limit values of the slope angle α of the mating guide surfaces 7 of the housing 1 and the corresponding slope angle α of the end surfaces 6 of the bearing blocks 3 to the radius of the head.

The greatest value is chosen from the condition of self-braking of these surfaces according to the formula

tgα _max ≤tgϕ;

where tgϕ = ƒ = 0.1 is the coefficient of friction of steel over steel;

then

α _max ≤6 °;

Thus, the slope angle α _{max of the} mating guide surfaces 7 of the housing 1 and the corresponding slope angle α _{max of the} end surfaces 6 of the bearing blocks 3 to the head radius α _max = 6 °.

The smallest limit value of the inclination angle α _{min of} these surfaces is determined from the condition of axial displacement S _O equal to the size of the abrasive grain when applying S _R equal to the cutting depth S _R = t according to the formula

,

,

where d _grain = 0.01 mm - the minimum size of the abrasive grain;

t _max = 0.25 mm - maximum cutting depth, mm

0.04 = tgα _min

α _min = 2 °

Thus, the slope angle α _{min of the} mating guide surfaces 7 of the housing 1 and the corresponding slope angle α _{min of the} end surfaces 6 of the bearing blocks 3 to the head radius α _min = 2 °.

Under the action of a two-stage piston 5, the sleeve 9 is deformed in the axial direction and acts on the base 8 of the carrier blocks 3 with an outer surface, which at the same time move in the radial direction (S _R ) and provide a uniformly distributed application of radial load, which ensures the coaxial arrangement of the blocks of bars, ensures accuracy shape of the machined cylindrical hole and improves the quality of its surface.

Thus, the use of a honing head containing a housing, bearing pads with abrasive bars fixed by return springs, made with end surfaces at an angle of 2-6 degrees to the radius of the honing head and installed in the housing with simultaneous axial and radial movement of the bearing pads along the mating guide surfaces housing, installed in the stepped recess of the housing, an expandable element in contact with the bases of the bearing blocks, made in the form of a sleeve made of elasto dimensional material and a two-stage piston, provides an increase in mold accuracy with increased surface quality of the machined hole with maximum performance.

Claims (1)

A honing head comprising a housing, support pads with abrasive bars fixed by return springs, made with end surfaces at an angle of 2-6 degrees to the radius of the honing head and installed in the housing with the possibility of simultaneous axial and radial movement of the bearing pads along the mating guide surfaces of the housing, an expanding element in contact with the bases of the bearing blocks, and a rod mounted with the possibility of impact on the expandable element, characterized in that the expandable element NT is made in the form of a sleeve of elastomeric material installed in a stepped recess of the housing, and the rod is made in the form of a two-stage piston and is located at a small step in the hole of the sleeve.

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