RU131157U1 - SINGLE-COMPONENT DYNAMOMETER FOR MEASURING THE TANGENTIAL COMPONENT OF CUTTING FORCING - Google Patents

Abstract

One-component dynamometer for measuring the cutting force during turning, consisting of sensors, a cross-shaped elastic element located inside a rectangular frame on which the tool holder is mounted on the left, and a fixed plate mounted on the machine on the right, characterized in that the upper and lower cross-bar of the cross-shaped elastic element is fixed on a fixed plate, and the right and left planks of the cross-shaped elastic element are fixed on the frame with a tool post, the upper and lower planks of the elastic element in the places of attachment to the fixed plate has minor protrusions, allowing the elastic element and the tool holder attached to it to rotate under the influence of the tangential component of the cutting force without friction against the fixed plate, sensors for determining the deformation of the elastic element can be mounted on its upper, lower, left and right trims, while the frame , the tool holder and the plate form a closed sealed housing in which there is a cross-shaped elastic element, thus protected from the effects of the external environment and heating.

Description

The proposed utility model relates to the field of determining the parameters of the cutting process during turning and can be used in mechanical engineering, aircraft engine manufacturing, higher education institutions, research centers to determine the tangential component of the cutting force during blade cutting by turning critical and non-rigid parts, during research and training purposes.

Of the devices that are designed to determine the cutting forces during turning, the closest are:

“A method for determining cutting forces and a device for its implementation” (Patent No. 2082123 G01L 5/16 C1, 06/20/1997). The device comprises: a cutter mounted on two carriages independently movable, and having the ability to move in a plane parallel to the base of the cutter and the ability to rotate tangential and radial cutting forces in the plane of action relative to the axis of the carriage located closer to the workpiece. A linear scale and dynamometers attached to the carriages, by means of which the reactions of the supports in the carriages are determined, followed by the calculation of the tangential and radial components of the cutting forces.

The disadvantages of this device include the presence of friction pairs, which under high loads and small displacements are subject to fretting wear and introduce a significant error in the determined cutting forces. The presence of gaps in the joints reduces the rigidity of the structure, increases vibrations that distort the recorded cutting forces and lead to chipping of the cutting edge of the tool.

Dynamometer designs are also known, in which the tool holder housing is an elastic element: “The choice of a method for measuring cutting forces and measuring equipment during ultrasonic wood processing”.

Kolotushkin N.N., Tomashevich A.V. (BGITA, Bryansk, Russian Federation), (http - // science-bsea.narod.m / 2006 / les_2006 / kolotushkin_vybor.htm):

The device consists of the following main parts: a U-shaped tool holder in which the cutter is fixed; massive plate, which is fixed on the machine; between the tool holder and the plate, a rectangular-shaped hollow body is mounted inside, having through the grooves parallel to the axis of the cutter on all four sides, which reduce the rigidity of the body. A ring with a groove along the generatrix or without it can also be used as a housing. Due to the low rigidity of the housing, the tool holder with a cutter has the ability to move relative to the plate with a shank, on which micro displacement sensors are installed, which record micro displacements or strain gauges are glued.

The disadvantages of such dynamometers include the non-equal rigidity of the body with grooves in three mutually perpendicular directions, as a result of which the cutter does not perform plane but complex spatial movement (translational movement in three directions plus rotation around three perpendicular coordinate axes), as a result of which it becomes unclear, what forces cause displacements recorded by sensors. In addition, the low rigidity of the frame causes vibrations with high frequency and amplitude. It should also be noted the large dimensions of the considered dynamometers and poor protection from coolant and the resulting chips due to the external arrangement of measuring instruments for cutting forces and movements, which complicates the industrial use of dynamometers.

Closest to the proposed utility model is the dynamometer described in:

Technology of construction materials. Workshop on technological methods of processing blanks [Text]: Textbook / Yu. M. Baron, GP Dzelten, V.S. Kobchikov et al. / Ed. IN AND. Nikiforova. - SPb .: Publishing house of the Polytechnic. Univ., 2007 .-- 304 p., p. 86.

(http://detektorl337.wippiespace.com/Study/TKM/Uh_posobie_Nikiforova_pdf.pdf)

The device described in the training manual is a one-component dynamometer and consists of a cutter fixed in the tool holder. Grooves parallel to the axis of the machine are made on the part of the cutter cantilever protruding from the tool holder from above and below. Strain gages are glued in the grooves, registering the tangential component of the cutting force. The main disadvantage of this device is its narrow field of use, since the cutter itself is the elastic part of the dynamometer. If you need to measure the cutting force using another tool, you will actually need to re-create the dynamometer, which is difficult even if the dynamometer is used for educational purposes. The second disadvantage of the dynamometer is the proximity of the strain gauge to the cutting zone, because during processing, the cutter heats up to a temperature at which the strain gauge may be unreliable.

The advantage of the claimed dynamometer is the ability to accurately register the tangential component of the cutting force with various tools, compactness, protection of the elastic element with sensors from temperature fluctuations, coolant and chips.

This is possible due to the absence of friction pairs and the high rigidity of the elastic element in the direction of the radial and axial component of the cutting force; the tightness of the dynamometer is ensured by the location of the elastic element with glued strain gauges inside the device.

The technical result is an accurate determination of the tangential component of the cutting force by various tools, regardless of the effective radial and axial component of the cutting force.

The technical result is expressed in increasing the accuracy of measuring the tangential component of the cutting force, the protection of the measuring sensors from the external environment and the possibility of quick change of the cutting tool in the tool holder.

The technical result is achieved in that the elastic element is made in the form of a frame with a cross-shaped element inside. The upper and lower slats of the cross-shaped element are fixed on the fixed plate and come into contact with it with small protrusions, which exclude friction of the elastic element with the fixed plate. The right and left trims of the cross-shaped element are inextricably linked with the frame of the elastic element. The elastic element has high rigidity in the direction of action of the radial Py and axial Px components of the cutting force, and low rigidity in the direction of the tangential component of the cutting force Pz, due to which, when cutting, the elastic element bends only under the action of the force Pz and does not bend under the forces of Ru and Px , which increases the accuracy of measuring the tangential force Pz. Due to the absence of friction pairs, the accuracy of measuring the Pz force is increased by reducing friction losses. The strain gauges are glued onto the slats of the cross-shaped element, which is located in the frame of the elastic element. A tool holder is fixed on the left at the end of the frame of the elastic element, and on the right is a fixed plate, which together form a closed housing in which there is a cross-shaped element with sensors glued to it. Thanks to the hermetically sealed enclosure design, the measuring sensors are protected from exposure to elevated temperature, chips and coolant, thereby increasing the accuracy of measuring the force Pz, because The sensors operate under constant conditions in which they were calibrated. The tool holder has standard elements for fixing the tool with screws, which makes it possible to quickly change the tool in the dynamometer.

The diagram of a single-component dynamometer is shown in figure 1. -elastic element; and FIG. 2 is a rear view of the dynamometer.

The dynamometer includes:

The cross-shaped part 1 of the elastic element 6 (FIG. 1), having high rigidity in the direction of action of the radial Py and axial Px of the cutting force components, and low rigidity in the direction of the tangential component of the cutting force Pz. The upper and lower slats 2 of the cross-shaped element 1 are fixedly mounted on the plate 3 with the shank 4 (figure 2), through which the dynamometer is fixed on the machine. The upper and lower slats 2 of the cross-shaped element 1 have slight protrusions 13, which make it possible to rotate the elastic element 6 and the tool holder 7 fixed thereon without friction against the fixed plate 3. The left and right slats 5 of the cross-shaped element 1 are inextricably linked with the frame of the elastic element 6. Under the action of the tangential component of the cutting force Pz, the elastic element with the frame 6 and the tool holder 7 is elastically deformed and rotated in a counterclockwise direction. 8 - direction of rotation of the elastic element around the fixed center O under the action of the tangential force Pz. A tool 10 is fixed on the tool holder 7 with a bolt 9. To prevent friction of the elastic element 6 on the plate 3, a gap 11 of 0.2-0.3 mm is provided. The gap 11 appears due to the protrusions 13 on the strips 2. The gap 11 is filled with sealant, grease or sealed with a rubber cuff. Sensors 12 for measuring elastic deformations can be glued to the upper, lower, left and right trims of the cross-shaped elastic element 1.

When cutting under the influence of the tangential component of the cutting force Pz, the cutter fixed in the tool holder 7 rotates together with the elastic element 6 in the plane of action of the forces Pz and Py around an axis close to the center O (Fig. 1, Fig. 2). Due to the high stiffness of the elastic element 6 in the direction of action of the forces Ru and Px, the deformation of the elastic element in the direction of action of these forces is negligible. The registration of elastic deformations is carried out by sensors 12, which are glued to the strips 2 and 5. The upper part of the strips 2 having the protrusions 13 remains stationary due to the fact that the strips 2 are fixed by the protrusions 13 on the fixed plate 3.

Claims (1)

One-component dynamometer for measuring the cutting force during turning, consisting of sensors, a cross-shaped elastic element located inside a rectangular frame on which the tool holder is mounted on the left, and a fixed plate mounted on the machine on the right, characterized in that the upper and lower cross-bar of the cross-shaped elastic element is fixed on a fixed plate, and the right and left planks of the cross-shaped elastic element are fixed on the frame with a tool post, the upper and lower planks of the elastic element in the places of attachment to the fixed plate has minor protrusions, allowing the elastic element and the tool holder attached to it to rotate under the influence of the tangential component of the cutting force without friction against the fixed plate, sensors for determining the deformation of the elastic element can be mounted on its upper, lower, left and right trims, while the frame , the tool holder and the plate form a closed sealed housing in which there is a cross-shaped elastic element, thus protected from the effects of the external environment and heating.

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