RU2199099C2 - Procedure testing torque and pneumatic gear for its realization - Google Patents

Abstract

FIELD: measurement technology, torque measuring units. SUBSTANCE: in correspondence with invention pneumatic chamber K houses bellows sealed on one side which divides it into two isolated pneumatic chambers equal by volume. Compressed air is supplied simultaneously inside and outside of bellows. Compressed air is released to atmosphere through reference clearance S1 between first nozzle and reference surface. At same time compressed air is also released to atmosphere through measurement clearance S2 between second nozzle and springy plate which one end is attached to body of pneumatic chamber. Controlled torque is applied to end of springy plate. Being deformed springy plate changes measurement clearance S2, air flow rate and pressure alter and corrugations of bellows start deforming. Value of applied torque is evaluated by degree of movement of corrugations of bellows. Gear for realization of procedure has base with two columns attached to it and rigidly supporting plate-disc with pressed-in ball bearing in which inner race stepped roller is mounted for turning. Controlled torque is applied to upper step of roller. L-shaped lever to which right parts of main and additional springy plates are attached, their left parts being attached to column made fast to base, is made fast to butt of lower step of roller. Gear includes bellows, indicator, pipe unions, air conduits. EFFECT: widened technological capabilities, enhanced accuracy of procedure and gear. 4 cl, 4 dwg

Description

 The invention relates to measuring equipment and can be used in various industries for measuring torque developed by technological equipment, such as wrenches, with a tightened tightening of threaded connections.

 A known method of controlling the tightening force of the threaded joints [1], which consists in the initial tightening of the nut to the zero position by the specified force and further tightening of the nut with a control of the angle of rotation of the nut, in order to increase the accuracy of the control of the tightening forces, an additional tightening of the nut is made while measuring the torque the moment on the nut and in relation to the product of the whole applied moment by the angle increment to the moment increment, the zero position of the nut rotation angle is determined, and the end first rotation angle by which they judge the tightening force is determined from the difference between the desired rotation angles of zero and nuts.

 The disadvantage of this control method is its cumbersome implementation, which entails an increase in the complexity and, thus, reduces the measurement efficiency and technological capabilities. In addition, the accuracy of measurements is not sufficient in all cases, since each of the stages of the proposed set of actions invariably causes the appearance of both random and systematic errors.

 A known method of controlling the tightening force using pneumatic washers [2], which consists in the use of washers of a special design when assembling threaded joints, and measuring the air flow passing through the washer annular slot (when tightening the nut or bolt, the slot decreases, air consumption too), and the magnitude of the change in these parameters is judged on the degree of tightening of the threaded joints.

 The disadvantages of this method is the high complexity of the implementation due to the need to use special washers, as well as significant measurement errors, which reduces its effectiveness and limits technological capabilities and, therefore, the scope will be very limited.

 A known method of measuring the energy parameters of impact wrenches and a device for its implementation [3], the essence of which lies in the fact that the impact wrench is applied to the impact wrench by a force-sensing element, as a result of which the impact energy is converted into thermal energy. In the period between the predetermined initial and final temperatures, the number of impact wrenches is measured, and the energy of a single impact is determined as the quotient of the mass heat and the difference between the final and initial temperatures of the power-receiving element by the measured number of impact wrenches.

 At the same time, in the case of the power-sensing element of the device there is a shank that picks up shocks from the tested wrench, and temperature and acoustic sensors record changing parameters.

 The disadvantages of this technical solution are complexity and cumbersomeness, which limits technological capabilities, as well as insufficiently high measurement accuracy, due to the use of several different types of sensors. In addition, the technical solution is suitable only for devices of shock-pulse action.

 A known method of measuring torque and a device for its implementation [4], the essence of which is to use strain gauges glued to an elastic plate, registering the bend of the latter, the value of which is used to judge the degree of tightening. In this case, external torque is applied to the elastic plate as a concentrated force through the lever from the shaft located in the bearing assembly.

 The disadvantages of this method, despite the relatively high measurement accuracy, is the complexity and high complexity of the implementation, since the use of strain gauges necessitates a stabilized source for their power, as well as an electric signal amplifier. In addition, in the case of application of shock-impulse loads (for example, when measuring torques of impact wrenches), the use of strain gauges also causes significant measurement errors. Together, this limits the technological capabilities of both the method itself and the device for its implementation, which ultimately reduces the efficiency indicators.

 A device for adjusting wrenches [5] is known, comprising a base, a measuring unit mounted on it and a loading unit electrically connected with it, including a housing, a sleeve with a central profile hole arranged to rotate therein, designed to interact with a turnkey wrench, and an elastic element fixed to the housing at one end with strain gauges glued on it, kinematically connected at the other end with a sleeve, in which, in order to expand technological possibilities due to the stepwise adjustment of the measuring range of torque created by the adjustable wrench, the elastic element is placed in the housing perpendicular to its axis, the kinematic connection of the elastic element with the sleeve is made in the form of a L-shaped lever, one shoulder of which is fixed to the end of the sleeve, the other is rigidly connected with the elastic element, and the device is equipped with perpendicular to its axis installed in the housing with the possibility of axial fixed movement with two studs and two additional elastic elements Tammy, each of which one end is fixed to a corresponding stud and is designed to interact with shoulder L-shaped lever rigidly associated with an elastic element. In addition, the studs are installed in the housing at an angle of 45 degrees to the axis of the elastic element, and the axis of the studs is perpendicular to one another.

 The disadvantages of this device are the cumbersome mutual arrangement of the elements of the internal kinematics, which leads to insufficient manufacturability of the design as a whole, due to the inaccessible placement of both the main elastic element with strain gauges and two other auxiliary elements mounted on mutually perpendicular studs. In aggregate, this leads to a high laboriousness of adjustments of the device for various operating modes, as well as significant costs associated with the measurement method implemented on the basis of electrotensometry. All this limits technological capabilities, and in the case of setting up shock-pulse devices, significant measurement errors arise.

 The closest technical solution (for the device) is a device for adjusting wrenches [6], containing a base, a measuring unit mounted on it and an electrically connected loading unit, including a housing, a sleeve with a central profile hole that can be rotated therein, designed to interact with a turnkey wrench of a adjustable wrench, and an elastic element fixed to the housing at one end with strain gauges glued to it, the other end of which is kinematically connected to the sleeve through the L-shaped lever, one shoulder of which is rigidly connected to the elastic element, and the other shoulder is fixed to the sleeve, in which, to automate measurements and ease of operation by increasing the manufacturability of the device, the elastic element is placed perpendicular to the axis of the profile hole of the sleeve, in the case below and parallel to the axis the main elastic element is placed a drum made in the longitudinal direction in the form of a stepped roller, at one end of which six additional elastic elements are fixed, kinematically connected data through the L-shaped lever with the main elastic element, and the other end of the drum is mounted with the possibility of fixed rotation in the bearing sleeve, pressed into the housing.

 The disadvantages of the prototype are the complexity of the elements of internal kinematics and the very use of strain gauges, which necessitate the design of the device in the form of two blocks: measuring and power. In addition, the use of methods of electrotensometry, in general, limits the technological capabilities and scope, since in the case of torque control applied in the form of shock-rotational pulses (when setting impact wrenches), the measurement error increases significantly.

 The purpose of the invention is the expansion of technological capabilities and increased measurement accuracy due to the pneumatic circuit with a bellows included in the back pressure mode.

 The technical result (by the method) arising from the purpose of the invention is achieved by taking a pneumatic chamber and securing a bellows hermetically sealed on one side, dividing it into two mutually isolated pneumatic chambers of equal volume, and then compressed air is supplied under pressure from 0.15 up to 0.2 MPa simultaneously inside and outside the bellows, while compressed air acts on the outer surface of the bellows and through the reference gap S1 between the first nozzle and the reference surface, comprising from 0.1 to 0.2 mm, is discharged into the atmosphere; at the same time, compressed air acts on the inner surface of the bellows and through the measuring gap S2 between the second nozzle and the elastic plate, one end of which is attached to the housing of the pneumatic chamber, from 0.1 to 0.2 mm is also discharged into the atmosphere, then to the other end the elastic plate is applied controlled torque, deforming, the elastic plate changes the measuring gap S2, while changing the air flow through the measuring and reference nozzles, as well as the air pressure inside and outside the bellows and the corrugations of the latter begin to deform, the degree of applied torque is judged by the degree of movement of the bellows corrugations.

 Thus, the purpose of the invention by the method is achieved both in terms of expanding technological capabilities, and in more accurate registration of external (both "smooth" and pulsating) loads, which is facilitated by an additional "intermediate working fluid" - the air gap, implemented by the proposed method.

 The technical result (according to the device) arising from the purpose of the invention is achieved by the fact that the base of the device with two racks attached to it, rigidly holding the disk plate with a pressed-in ball bearing, in the inner ring of which a stepped roller is rotatably placed, to the upper stage of which is applied controlled torque, an L-shaped lever is rigidly mounted on the end of the lower stage of the roller, to which the right parts of the main and additional elastic plates are attached, the left parts to which are attached to a rack, rigidly mounted on the base and, due to the fact that one of the racks of the device has a support plate with a pneumatic chamber, inside of which there is a bellows rigidly attached with one end to the base plate and the other hermetically sealed end contacting the movable leg dial type indicator, a bracket with an adjusting bolt and a lock nut is fixed on the base plate, between the end of which and the pneumatic chamber output channel there is a gap pneumatically connected to the outer surface new bellows; a measuring nozzle is fixed in the hole of the other rack of the device, mounted perpendicular to the main elastic plate with a gap to it and pneumatically connected through the nozzle and air ducts to the inner surface of the snlfon.

 The functional purpose of the main elastic plate is to react to the applied torque together with the measuring nozzle, and this leads to a change in the measuring gap (fixed value during measurements).

 The functional purpose of the additional elastic plate is to provide one or another range of torque measurements due to the "addition of stiffness" (various thicknesses of additional elastic plates).

 The “reference branch” of the device is the part of the chamber that encompasses the outer surface of the bellows through which compressed air passes and the inlet and outlet channels of the chamber, and the end of the adjusting bolt functions as the reference surface.

 The implementation of the measuring nozzle in the form of a pneumatic tip, and the reference nozzle in the form of a channel of a pneumatic chamber, in which a bellows is sealed at one end and separating the pneumatic chamber into two mutually isolated pneumatic branches: the measuring and reference branches, together provide the following.

 In the case of rotation of the stepped roller, the L-shaped lever simultaneously deforms the main and additional elastic plates and, thus, changes the measuring gap; and the reference nozzle, as an element of kinematics, is absent, and its functions are performed by the channel in the wall of the pneumatic chamber, which simplifies the design of the device as a whole and helps to increase the accuracy of measurements.

 The presence of an additional elastic element (replaceable), installed parallel to the main one, implements "stepwise switching" of stiffness, that is, due to the installation of an additional elastic plate of appropriate thickness, the required range of measured torques can be selected.

 Thus, due to the above measures: the totality and sequence of actions according to the method, shape and location of the kinematics elements of the device, the purpose of the invention seems to be achieved.

 Figure 1 presents a diagram of the proposed method of torque control; figure 2 - pneumatic device for implementing the method of figure 1, the main section; figure 3 is the same, a top view of figure 2; figure 4 is the same, a section aa in figure 3.

 The implementation scheme of the method for controlling the torque contains (Fig. 1): pneumatically interconnected - a shut-off valve B, a filter-moisture separator ФВ, a pressure-reducing valve with a pressure stabilizer of the Republic of Kazakhstan, a pressure gauge M, pneumatic throttles of the reference and measuring "branches" of the proposed circuit, Other 1 and Dr. 2, a pneumatic chamber K with an SF bellows rigidly fixed in it, the other hermetically sealed end of which is connected with the BI indication unit (for example, with a dial type indicator), an ES reference nozzle with a reference surface of the actuator; installed with a clearance S1, a measuring nozzle of an integrated circuit with an elastic plate UP, installed with a gap S2, a node for sensing external torque of a PA (for example, a L-shaped lever placed in a ball bearing) mechanically connected with an elastic plate UP. In this case, the measuring and reference gaps of the circuit in the initial position are equal to each other, that is, S1 = S2.

 The method of torque control is implemented as follows.

 First, static loading-unloading of the elastic plate UE is carried out according to the standard method to eliminate hysteresis due to possible plastic deformations, and then with the probe set the reference S1 and measurement S2 gaps (within 0.1-0.2 mm), respectively, between the reference surface of the EP and elastic plate UP. Next, check the strength and reliability of all elements of the pneumatic circuit (pipeline) in order to minimize possible leaks of compressed air.

 The shut-off valve B is opened, and compressed air under pressure of 0.4-0.6 MPa from the compressor (not shown) or the industrial pneumatic network enters the PV filter-dehumidifier, where it is cleaned and then enters the pressure reducing valve with a pressure stabilizer, the setting of which sets the pressure at the outlet from it, within 0.15-0.2 MPa, which is controlled by the pressure gauge M. Then the compressed air flow is divided into two "branches": the reference one through the throttle Dr.1, and the measuring one through the throttle Dr.2.

 Passing further along these "branches", two streams of compressed air simultaneously enter the pneumatic chamber K, act on the outer and inner surfaces of the SF bellows and, at the same time, are released into the atmosphere through the reference S1 and measurement S2 gaps formed by nozzles with the ET reference surface and an elastic plate UP

 If these gaps are equal, S1 = S2, the SF bellows will be at rest, "since the pressure of the compressed air inside and outside the bellows will be the same (mutually balanced). In this case, the BI indication unit (for example, a clock-type indicator) in contact with loose at the end of the bellows SF, it will show the zero mark.For more precise adjustment of the zero mark of the display unit BI can be used pneumatic throttle dr.1 and dr.2.

 Thus, the circuit (figure 1) is in equilibrium and is ready to implement the proposed method of measuring torque.

 By applying the measured torque (for example, from a screwdriver through the L-shaped lever) to the torque sensing unit, the elastic plate UP is deformed and changes the size of the measuring gap S2 between the measuring nozzle IP and the first (i.e., elastic plate UP), which leads to the pneumatic circuit goes out of equilibrium and its imbalance occurs, since S1 ≠ S2. In this case, the air flow through the measuring IC and the reference ES of the nozzle changes, as well as the air pressure inside and outside the SF bellows and the corrugations of the latter (i.e., the SF bellows) begin to deform, and the amount of applied torque is judged by the degree of movement of the corrugations of the SF bellows by visual counting signal from the display unit BI.

 Pneumatic device that implements the above method (figure 1) and is designed to measure torque (for example, wrenches), contains (figure 2): base 1 and cover 2 with attached racks 3 and 4, rigidly holding the plate-disk 5 , with a pressed-in ball bearing 6, in the inner ring of which a stepped roller 7 is placed rotatably, a controlled torque is applied to the upper stage of which, an L-shaped lever 8 is rigidly mounted on the end of the lower stage of the roller 7 (Figs. 3 and 4), to which bo Lta 9 and 10 are attached to the right side of the main 11 and additional 12 elastic plates (figure 4), the left parts of which are bolted 13 and 14 are attached to the rack 15 (figure 3 and 4), rigidly mounted on the base 1.

 A support plate 16 with a pneumatic chamber 17 is installed on the lower part of the strut 4 (Fig. 2), inside of which there is a bellows 18, which is rigidly attached with one end to the support plate 16, and with the other hermetically sealed end, in contact with the movable leg 19 of the dial indicator (Fig. 2). 3).

 An angle 20 is also fixed on the support plate 16 (FIG. 3) with an adjusting bolt 21 with a lock nut 22, between the end of which and the output channel 23 of the pneumatic chamber 17 there is a reference clearance S1 pneumatically connected to the outer surface of the bellows 18 through the channel 24 and the fitting 25; and collectively this is the "reference branch" of the pneumatic device.

 The measuring nozzle 26 is installed with a gap S2 = 0.1-0.2 mm perpendicular to the main elastic plate 11 (figure 2) in the hole of the rack 3 and through the air duct 27 and the fitting 28 are pneumatically connected to the inner surface of the bellows 18 and the inlet channel 29 and the fitting 30 (figure 3); collectively, this is the "measuring branch" of the pneumatic device.

 Thus, the outer and inner surfaces of the bellows 18 belong respectively to the reference and measuring "branches" of the pneumatic device (back pressure mode) that implements the proposed method of torque control (figure 1).

 Pneumatic device operates as follows.

 An additional elastic plate 12 (fil 4) is previously fixed with bolts 10 and 14, the thickness of which, together with the main (non-replaceable) elastic plate 11, is selected on the basis of calculations for the measured range of torques (from the conditions of permissible deflection).

 Then, an indication unit is attached to the end of the bellows 18 (for example, a movable leg of a dial type is installed with an interference fit of ≈1 mm). Using probes (not shown), the same values (0.1-0.2 mm) of the reference S1 and the measuring gap S2 are set and fixed.

 After that, the pneumatic device (Fig. 2, 3 and 4) is connected to the pneumatic network through pneumatic throttles (not shown), in particular to air preparation devices (valve, filter-moisture separator, oil spray, pressure reducing valve with pressure stabilizer and pressure gauge). A valve (not shown in Figs. 2,3 and 4) allows access of compressed air (pressure 0.1-0.2 MPa) simultaneously to the reference and measuring branches.

 At the same time, compressed air passes through the nozzle 25 into the “reference branch”, the channel 26 enters the internal cavity of the pneumatic chamber 17 (FIGS. 3 and 2), presses on the outer surface of the bellows 18 and is vented into the atmosphere through the outlet channel 23; compressed air passes into the “measuring branch” through the nozzle 30, the channel 29 presses on the inner surface of the bellows 18 and through the nozzle 28, the air duct 27, the measuring nozzle 26 is also vented to the atmosphere.

 If necessary, a fine adjustment is made by pneumatic throttles of the reference and measuring branches (not shown) (more exact equality of pressure in both "branches" is established). An additional fine-tuning point is the display unit (for example, a dial-type indicator that is “corrected” to zero).

 Next, a torque is applied to the step roller 7 (FIGS. 2 and 4) from the device under test (not shown), and the latter, turning through a certain angle, simultaneously bends the right ends of the main 11 into an additional 12 elastic plates through the L-shaped lever 8 the left ends, rigidly bolted 13 and 14 to the rack 15 (figure 4). This changes the size of the measuring gap (S1 ≠ S2) between the measuring nozzle 26 and the main elastic plate 11 (Fig.2 and 3), which leads to a change in pressure and air flow in the entire "measuring branch", including inside the bellows 18 , and the corrugations of the latter begin to move, and the magnitude of these movements is transmitted to the movable leg 19 of the dial indicator, the scale of which is calibrated in units of torque (Nm).

 In this case, the calibration of the pneumatic device (the construction of the dependences of the indications of the scale of the display unit in Nm on the magnitude of the bending of the elastic plates 11 and 12) is carried out previously for each measurement range using weights.

 Thus, the measurement process is completely completed and the pneumatic device is disconnected from the pneumatic network or the work cycle is repeated with the next adjustable device (for example, another wrench).

LIST OF REFERENCES
1. A. c. USSR 647565, MKI G 01 L 5/24. A method of controlling the tightening forces of threaded joints. // Channov V.I., Ustinov V.V., Schukin V.A. Publ. 02.15.70., Bull. 6.

 2. 3inyaev V.I., Yampolsky O.A. Pneumotensometric method for controlling the tightening force of threaded joints. - Bulletin of mechanical engineering, 1968, 3, p. 48-49.

 3. A.S. USSR 1509645, MKI G 01 L 5/24. A method of measuring impact energy and a device for its implementation // Ustinov V.V., Honold N.A. Publ. 02/15/70, bull. 6.

 4. The patent of Germany 3804043, 1989 // MKI - G 01 L 3/00, 25 V 23/14.

 5. A. p. USSR 1609637, MKI B 25 V21 / 00, G 01 L 5/24. Device for adjusting wrenches // Lanshchikov A.V., Grinin G.P., Desyatov O.A., Aniskin A.Yu. Publ. 11/30/90, bull. 44.

 6. RF patent N 2112639, MKI B 25 V 21/00. G 01 L 5/24, Device for adjusting wrenches // Lanshchikov A.V., Moiseev V.B., Eremin Yu.A., publ. 06/10/98, bull. 6.

Claims (4)

 1. A method of controlling torque, which consists in applying it to an elastic plate, the degree of deformation of which is fixed by load cells calibrated in units of torque, and then displayed on an indicating device, characterized in that they take a pneumatic chamber, fix a bellows hermetically closed on one side , dividing it into two mutually isolated pneumatic chambers of equal volume, then compressed air is supplied under pressure from 0.15 to 0.2 MPa simultaneously inside and outside the bellows, while the compressed air is exposed to m on the outer surface of the bellows and through the reference gap S1 between the first nozzle and a reference surface, of from 0.1 to 0.2 mm, is discharged into the atmosphere; at the same time, compressed air acts on the inner surface of the bellows and through the measuring gap S2 between the second nozzle and the elastic plate, one end of which is attached to the housing of the pneumatic chamber, comprising from 0.1 to 0.2 mm, is also discharged into the atmosphere; Further, a controlled torque is applied to the other end of the elastic plate, deforming, the elastic plate changes the measuring gap S2, while the air flow through the measuring and reference nozzles changes, as well as the air pressure inside and outside the bellows and corrugations of the latter begin to deform, according to the degree of movement of the bellows corrugations judge the magnitude of the applied torque.  2. A pneumatic device for implementing the method of torque control according to claim 1, comprising a base with two struts attached thereto, rigidly holding the disk plate, with a ball bearing pressed in, in the inner ring of which a stepped roller is rotatably placed, to the upper stage of which is applied controlled torque, an L-shaped lever is rigidly mounted on the end of the lower stage of the roller, to which the right parts of the main and additional elastic plates are attached, the left parts of which They are attached to a stand rigidly mounted on the base, characterized in that a support plate with a pneumatic chamber is installed on one of the device stands, inside of which there is a bellows, which is rigidly attached with one end to the base plate and with the other hermetically sealed end contacting the movable leg of the sentry indicator type, on the base plate is fixed a square with an adjusting bolt and a lock nut, between the end of which and the output channel of the pneumatic chamber there is a gap pneumatically connected to the outer surface th bellows; a measuring nozzle fixed perpendicularly to the main elastic plate with a gap to it and through pneumatic fittings and ducts pneumatically connected to the inner surface of the bellows is fixed in the hole of the other rack of the device.  3. A pneumatic device for implementing the method of torque control according to claim 1 or 2, characterized in that the measuring nozzle is made in the form of a pneumatic tip, and the reference nozzle is in the form of a channel of a pneumatic chamber, in which a bellows separating a pneumatic chamber sealed from one end is placed into two mutually isolated pneumatic branches: measuring and reference.  4. Pneumatic device for implementing the method of torque control according to any one of claims 1 to 3, characterized in that the additional elastic element is installed parallel to the main one and their joint stiffness corresponds to a given range of measurements of torque.

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