RU2188116C1 - Apparatus for mounting grinding disc - Google Patents

Abstract

FIELD: machine tool manufacture, possibly high-speed and depth grinding of different hard-to-grind materials having tendency to burnouts. SUBSTANCE: apparatus includes housing and connection flange. Sleeve is pressed-in to housing; it serves as sliding bearing. Stud rigidly fixed to connection flange through shock-absorbing sleeve enters groove of housing. Torsion member in the form of strip plate is arranged in such a way that its one end is placed in axial groove of housing and fixed to it by means of cross pin and its other end is placed in axial groove of connection flange where it is stationary fixed by means of cross pin. Apparatus allows to excite tangential-axial oscillations due to variable force occurring in zone of tool and blank contact at using grinding discs inclined by acute angle to plane normal relative to rotation axis and elastic member in the form of torsion strip plate. Vibration type rotation of disc allows to omit separate vibration mechanism with special drive unit. EFFECT: significantly simplified design of apparatus for mounting grinding disc for vibration grinding, enhanced reliability, lowered size and mass of apparatus. 4 dwg

Description

 The invention relates to machine tool industry, machining with an abrasive tool, and can be used for high-speed and deep grinding of various hard-grinding materials, prone to burns.

 A device in the form of a faceplate for attaching a grinding wheel, consisting of two clamping flanges, between which the tool is installed [1]. Moreover, in the middle part of one of the flanges, made in the form of the outer and inner surfaces of the rotation hyperboloids, there are elastic elements formed by longitudinal grooves.

 The disadvantages of the known device is the inability to excite cyclic oscillations due to the absence of a variable in magnitude of force cyclically acting on the elastic elements. Due to the physical processes occurring in the contact zone of the grinding wheel with the workpiece under constant cutting conditions, there is a constant cutting force that is greater than the torsional stiffness of the device. This constant force in one stroke of the grinding machine table forces only once to perform torsional oscillation of the grinding machine relative to the spindle. As a result, this device will make one oscillatory movement when changing the direction of the longitudinal feed. Cyclic vibrational vibrational movements with the help of this device can be carried out if the cutting regimes are cyclically changed (longitudinal feed, cutting depth, rotational speed, and other factors), which is very difficult and will lead to additional design and manufacture of the vibration pathogen.

 As a prototype and closest to the proposed device for mounting the grinding wheel, comprising a housing and a clamping flange, while it is equipped with a transitional flange with a shoulder, two oblique washers designed to install the grinding wheel at an angle to the plane of rotation and a torsion bar in the form of a sleeve, in the middle part of which grooves are made, and at the ends there are collars, one of which is rigidly connected to the housing and the other to the adapter flange, the torsion sleeve being located between the housing and the adapter flange and coaxial to them [2].

 The disadvantages of the known device are the complexity of the design of the torsion sleeve and the high cost of its manufacture, as well as the rapid wear of the outer and inner cylindrical surfaces due to the presence of grooves and a small area of contact with the mating surfaces of the housing and the transition flange. When the above-mentioned surfaces of the torsion sleeve are worn and a gap appears, vibration resistance, accuracy and roughness of the treated surface are sharply reduced. In addition, the device itself is characterized by large diameters and requires additional bore holes in the grinding wheel, and this reduces the utilization of abrasive material.

 The objectives of the invention are to simplify the design, reduce the size, improve manufacturability in the manufacture and assembly and reliability due to the rotation and axial movement of the tool by means of a torsion bar in the form of a bar located on the axis of the spindle of the grinding machine.

 This is achieved using the proposed device for attaching the grinding wheel, comprising a housing and a transitional flange, while it is equipped with a sleeve pressed onto the housing and acting as a sliding bearing, a pin fixedly connected to the transitional flange on which the shock-absorbing sleeve located in the groove of the housing is located , and a torsion bar in the form of a bar located at one end in the axial groove of the housing, and fixedly connected to it using a transverse pin, the other end in the axial groove of the adapter flange and with it Uniform fixed by a transverse pin.

Figure 1 shows the proposed device for mounting the grinding wheel at an angle to the plane of rotation, a longitudinal section; figure 2 is a left view A in figure 1; figure 3 is a General view of the device, rotated relative to the previous (figure 1) position 180 ^o ; figure 4 is a view of B in figure 1.

 The device for attaching the grinding wheel 1 comprises a housing 2, which has on the right (according to FIG. 1) a flange with threaded holes 3 for mounting on a spindle (not shown in FIG. 1) of the grinding machine; an adapter flange 4 with a shoulder with an oblique end face 5, on which the grinding wheel 1, oblique washer 6 and nut 7 are used to fix the tool with the help of shims at an angle α to the plane perpendicular to the axis of rotation.

 A sleeve 8 is pressed onto the cylindrical outer surface of the housing 2, which acts as a sliding bearing. The adapter flange 4 on a sliding fit without a gap between the hole of the flange and the sleeve 8 is mounted coaxially on the housing 2.

 The torque is transmitted from the housing 2 to the transitional flange 4 and further to the grinding wheel 1 by means of a torsion bar 9 located at one end in the axial groove of the housing 2 and fixedly connected to it using the transverse pin 10, the other end in the axial groove of the transitional the flange 4 and is connected to it stationary by means of a second transverse pin 11.

 The limiter of the angle of rotation of the transitional flange 4 with the circle 1 relative to the housing 2 is a pin 12, fixedly connected at one end to the transitional flange 4, on the other - there is a shock-absorbing sleeve 13, which is included in the groove 14 of the housing 2.

 The elastic element 9 - the torsion bar provides the possibility of relative rotation of the adapter flange 4 on the housing 2 with an increase in cutting forces and the return of the flange to its original position with a decrease in forces, contributing to the occurrence of torsional or tangential vibrations.

 In addition, the torsion bar 9, twisting with an increase in cutting forces and untwisting with a decrease in them, increases and decreases in length, thereby moving in the axial direction the flange 4 with the circle 1 and contributing to the excitation of axial vibrations.

Due to the physical processes occurring in the contact zone of the grinding wheel 1 inclined at an acute angle to the plane perpendicular to the axis of rotation, with the workpiece, such as: delay in the grinding force with respect to elastic displacements; the cyclic occurrence and the longitudinal action of the force P _x during the counter-running of the end face of the grinding wheel on the machined stock allowance moving with the longitudinal feed S _CR ; the absence or fall to a minimum of force P _x with the coincidence of the force and the longitudinal supply of the workpiece; a decreasing dependence of the friction force on speed, etc., the grinding wheel 1 performs torsional-axial or tangential-axial vibrations.

A device for attaching a grinding wheel works as follows. The grinding wheel, installed at an angle to the plane of rotation, provides an oscillation of the thermal field, allows you to intensify the machining process due to the increase in the arc of contact of the wheel with the workpiece and improve the conditions of tool self-sharpening. In this process, when moving the contact zone of the circle with the workpiece towards S _pr longitudinal supply of the workpiece (figure 3) there is an additional axial force P _x cutting abrasive grains that are at the end and are involved in the processing. This circumstance forces the torsion bar to spin at a larger angle and decrease in length.

When moving the zone of contact of the circle with the workpiece along the way S _pr longitudinal supply of the workpiece (Fig. 1), the force P _x will change direction and decrease in magnitude. The decrease in the force P _x is due to the decrease in the removed allowance, since the grinding wheel cuts already on the previously polished (see above) surface, while the force P _x causes the torsion bar to unwind.

 As a result of such interaction of the wheel with the workpiece, torsional-axial frictional self-oscillations with an amplitude arise, depending on the stiffness of the elastic element, cutting conditions, etc.

 Vibrations in these directions create a cross-movement of abrasive grains relative to the feed rate of the workpiece and periodically change the cutting speed and friction force. Thanks to this, material removal and chip formation are facilitated, self-sharpening of abrasive grains, the quality of the treated surface are improved, the processing productivity is increased several times and the energy consumption for cutting and friction is reduced compared to similar indicators with traditional grinding methods.

 In the proposed device, the torsional-axial movements of the grinding wheel are achieved due to the variable force arising in the zone of contact of the tool with the workpiece when using wheels installed at an acute angle to a plane perpendicular to the axis of rotation, i.e. with an axially offset cutting layer, and an elastic element of the torsion bar.

 Such a vibrational rotation of the wheel eliminates the need for a separate vibration mechanism with a special drive, which greatly simplifies the design of the mounting device of the grinding wheel for vibration grinding, increases its reliability and improves overall mass performance.

Sources of information taken into account
1. A.S. USSR 961933, class 24V 45/00, 1982.

 2. RF patent 2146600, cl. 24V 45/00. Stepanov Yu.S., Afanasyev B.I., Borodin V.V. Device for attaching the grinding wheel. Application 98120071/02, application. 11/05/98, publ. 03/20/2000. Bull. 8 is a prototype.

Claims (1)

 A device for attaching a grinding wheel comprising a housing and a transitional flange, characterized in that it is provided with a sleeve pressed onto the housing and acting as a sliding bearing, fixedly connected to the transitional flange by a pin on which the shock-absorbing bush located in the groove of the housing is located, and a torsion bar in the form of a strip located at one end in the axial groove of the housing and fixedly connected to it by means of a transverse pin, and the other end - in the axial groove of the adapter flange and fixedly connected to it with with the help of the cross pin.

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