RU2597630C2 - Pneumatic control-diagnostic bench - Google Patents

Abstract

FIELD: tools.

SUBSTANCE: invention relates to devices for testing of threaded joints and adjusting nut runners. Device comprises mounting plate 1, mounted thereon support 2, brackets 3 and 4, as well as crown bushing 5 installed on support 2, auxiliary bushings 6 and 7, replaceable bushings 8 and 9. In crown bushing 5 is pressed a central part of thrust bearing 10 on which on both sides rest bushings 6 and 7, with which by screws 11 are connected replaceable bushings 8 and 9. Test bolt 12 rests by head on replaceable bushing 8, and nut 13 rests on replaceable bushing 9. Crown bushing 5 is connected with brackets 3 and 4 by means of elastic elements 14 and 15 bolts 16. On crown bushing 5 there are also brackets 17-20, connecting it with auxiliary bushes 6 and 7 by means of elastic elements 21-24. Elastic element 21 is moved from bushing 9 by means of welding two rigid angles 33. On box 25 there are bushings 26 and 27, in which are retained pneumatic nozzles 29 and 30. Bushing 28 with nozzle 31 is attached to plate 1 by means of angle 32. Vibration simulation unit comprises motor 38 with eccentric disc 37 for reproduction of impact pulses at head of test bolt 12.

EFFECT: technical result consists in broader technological capabilities and simplification of design.

3 cl, 11 dwg

Description

The invention relates to mechanical engineering, in particular to devices for testing PCs and tuning wrenches, and can be used in any of its industries for assembling PCs.

A device [1] is known, comprising a base with two struts attached to it, rigidly holding the disk plate, with a pressed ball bearing, in the inner ring of which a stepped roller is rotatably placed. A controlled torque is applied to the upper stage of the roller. An L-shaped lever is rigidly mounted at 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 are attached to the rack, rigidly mounted on the base. The device also contains a bellows, indicator, fittings and ducts, etc.

The disadvantages of this device are very limited technological capabilities, as it allows you to measure only the torque developed by the wrench (only one parameter, as stated).

A known design for measuring and monitoring the tightening force of the PC [2], comprising a fastener with an axial hole, a hollow body with a spring-loaded rod placed inside it, kinematically connected at one end with an indicator rod mounted on the body, in which there is a sleeve mounted on the body, however, one end of the housing is made in the form of a collet placed inside the sleeve, in the inner cavity of which a thrust washer and a ring in contact with the collet are fixed, and between the inner hole of the thrust washer and the surface of the collet, a clearance is made, the other end of the body is made in the form of a threaded shank installed in the axial hole of the fastener, the free end of the spring-loaded rod is made spherical and installed in contact with the bottom of the axial hole of the fastener, moreover, the collar has a spherical bearing surface on the rod, and the spring mounted on the stem inside the housing. The execution of the end of the housing in the form of a collet and its placement inside the sleeve, mounted on the housing, provides the possibility of axial fastening of the connecting sleeve of the indicator for a smooth, without jamming the forward stroke of its measuring rod. Also, the threaded shank of the housing is equipped with a thrust sleeve made with a height exceeding the undercut of its thread.

Moreover, the case itself is mounted on the end of the fastener and is fixed in the thread of the latter, located in the axial hole.

The design drawback is limited technological capabilities, since for practical use of the device, free access to the PC is required.

A device [3] is known for determining the parameters of the tightening of threaded connections, containing the studied threaded connection, interchangeable latch, spacer and pusher for transmitting the tightening force to the supports of the force measuring device, which is used as a tensile testing machine, the interchangeable latch has a groove for fixing one of the parts of the threaded pair and the tightening of the threaded connection is performed with another part of the threaded pair by means of a torque wrench.

The design drawback is the need to rearrange the interchangeable device lock to determine either the friction moment in the thread or at the end of the bolt, which ultimately increases the complexity of the measurements.

The closest technical solution, in comparison with the proposed one, is a stand [4], containing a base, two brackets coaxially located and a stand mounted on the base with the possibility of longitudinal fixed movement, rotatably placed in the respective brackets and spring loaded relative to the latter in a tangential direction by elastic sleeve plates designed to accommodate a test bolt with a nut in them, mounted in a rack with the possibility of rotation of the drive shaft, designed is designed to interact with a torque wrench or wrench, a rotation angle sensor associated with the drive shaft, a cap wrench designed to interact with the head of the test bolt, mounted on the base of the displacement sensor, designed to interact with the end of the threaded end of the tested bolt, characterized in that, in order to expand technological capabilities, the unit that reproduces operational fluctuations is made in the form of a pneumatic hammer and is placed relative to one of the ends of the simulator threaded of the connection on the stand, rigidly attached to the base of the device, and the nut angle meter is made in the form of a removable arrow, which is placed on the nut, and a dial with a division value of 1 degree is mounted on the sleeve, in which one of the simulators of the threaded connection is placed.

This stand allows you to register the torque at the end and in the threaded part, the rotation angle, the tightening force and to fix the attenuation of the threaded joint after a specified time of its operation.

The disadvantages of the prototype are:

1) limited technological capabilities, since the stand allows the ability to work only with torque (or limit) wrenches and impact wrenches (static), due to the fact that strain gauges (used in the measurement scheme and the principle of their action) under shock loads give unreliable results; in addition, the very use of strain gauges in principle (i.e., by default) means - the need for a signal amplifier and a stabilized power source, which complicates the measurement process;

2) the impossibility of registering the value of the applied torque, often necessary to adjust the wrenches and perform preliminary calculations for a specific threaded assembly;

3) the complexity of the design of the site of application of vibrational vibrations, since the pneumatic hammer (in principle) has zero-beam control of its duty cycle, which ultimately complicates the design.

The purpose of the invention is the expansion of technological capabilities and simplification of the design due to:

a) the use of pneumatic sensors of the nozzle-damper type [5] (instead of strain gauges), which can reliably record (for example, shock loads) through the "intermediate body" (ie, the air gap through which compressed air flows into the atmosphere) [5];

b) adding an applied torque registration unit;

c) changes in the shape and arrangement of the elements of the application site of vibrational vibrations (instead of a pneumatic hammer, a cam (eccentric disk) mounted on the output shaft of the electric motor to which vibrations are transmitted to the newly tightened PC, thus simulating the initial period of operation.

The goal is achieved by the fact that:

1) a different principle has been proposed for recording the mismatch signals from elastic plates that respond to each controlled parameter (instead of strain gauges, pneumatic sensors in which bellows are sensitive elements);

2) added details and elements, creating the possibility of measuring also applied torque;

3) the vibration application unit is simplified (instead of a pneumatic hammer, an eccentric disk on the motor shaft, which reproduces vibrations that mimic the initial period of PC operation.

In FIG. 1 shows a pneumatic control and diagnostic stand, 3-D axonometry;

in FIG. 2 is the same, gauge type measurement scheme for each of the pneumatic channels;

FIG. 3 - the same, 3-D perspective view of the measuring unit of the device;

FIG. 4 - the same, end view of the power unit of the device;

in FIG. 5 - the same, a longitudinal section along the power block;

in FIG. 6 is the same end view of the bolt elongation measurement assembly;

in FIG. 7 is the same side view of the extension measurement unit;

in FIG. 8 is the same, a top view of the node measuring elongation;

in FIG. 9 - same, vibration application unit;

in FIG. 10 is the same diagram of elements of the rotation angle measuring unit;

in FIG. 11 is the same, end view of the node measuring the angle of rotation.

The device contains the following main nodes (Fig. 1): power and measuring units, pneumatically connected by air ducts (Fig. 2) with a measuring unit (Fig. 3), sensors of the nozzle-damper type [5], as well as a number of other auxiliary elements, fixed on one base and, thus, forming the product (Fig. 1).

The measuring unit (Fig. 2 and 3), which is used to record each of the four pneumatically controlled parameters, contains: air preparation elements - a PV pneumatic switch, a filter-moisture separator with a PV oil spray and a pressure reducing valve with a pressure regulator of the Republic of Kazakhstan; elements of fine adjustment of the air flow - pneumatic throttle ДР1 and Др2; manometer M; a pneumatic sensor including a sensing element — an SF bellows in contact with its closed end with a BI indication unit (a movable leg of a dial type indicator) mechanically combined into a single unit (Fig. 3); the reference surface of the EI, which forms a reference gap S1 with one of the nozzles, where the nozzle exit hole is perpendicular to the center of symmetry of the plate surface, the nozzle hole is 50% of the length from each edge of the plates; the elastic plate UP, which together with the second nozzle (located in the power unit of the device opposite the elastic plates) forms a measuring gap S2.

The power unit of the device (Fig. 4 and 5) contains: mounting plate 1, which is rigidly fixed to the plane of the table collector. Attached to it are: a support 2 with a bearing segment (to exclude possible deflection of the plates due to the weight of the central part of the power unit of the device), as well as brackets 3 and 4 (for rigidly fixing the position of the elements of the central part).

The castellated sleeve 5 is mounted on the support 2. Auxiliary bushings 6 and 7 are placed therein for fixing the replaceable bushings 8 and 9 (PC simulators) therein.

The thrust ball bearing 10 is pressed into the castellated sleeve 5, and through its outer rings, auxiliary bushings 6 and 7 are installed on both sides, with screws 11 connecting them to the replaceable bushings 8 and 9.

Test subjects - the bolt 12 rests with the head on one of the replaceable bushings, and the nut 13 on the other. The castellated sleeve 5 is connected to the brackets 3 and 4 by means of elastic elements 14 and 15 (plates) by bolts 16.

Brackets 17, 18, 19 and 20 are fixed to the castellated sleeve 5 by means of elastic elements 21, 22 (designed to record the moment in the threaded joint bolt 12 - nut 13), and 23, 24 (designed to record the moment under the head of the bolt 12), so that the auxiliary bushings 6 and 7 are allowed to rotate together with the outer rings of the bearing 10.

To ensure uniformity of calculations (in the case of measurements), it is advisable that all plates were able to bend only in the direction away from the nozzles, and the elastic element 21 (Fig. 4) was moved away from the sleeve 9 by welding (welding) two rigid squares 33 (namely this sleeve 9 is structurally and different from sleeve 8).

Box 25 (Fig. 5) closes the entire structure (to simplify the perception of Fig. 1 - not shown), and also serves to attach bushings 26 and 27, in which pneumatic nozzles 29 are installed (for recording changes in clearance S2) and 30 (also to register clearance S2). The sleeve 28 with the nozzle 31 (for recording changes in the gap S2) is attached to the plate 1 using the angle 32.

Thus, in the case of bending of the elastic elements of the UE (Fig. 2), this will correspond to the pneumatic differential measurement scheme of the gauge type, similar to that described in [1].

The rotation angle measuring unit (Fig. 4) contains a rail 34, which is movably mounted along the guide sleeves 36 and a gear 35. A scale is applied to the rail 34 for ease of visual fixation of the values (Fig. 11), and the gear itself 35 is fastened to a tightened one the nut is possible due to the small thickness, its central hole and radial cuts.

The node for measuring the elongation (Fig. 6, 7 and 8) of the bolt contains a nozzle 45, an adjusting bolt 46, two rigid corners 40 (the second is not shown) capable of being brought in and taken away (that is, they can slide) along the guides 41 and 42 as shown in FIG. 4, 5, 6.

To ensure the accuracy of measurements, slip pairs 40-41 and 40-42 are fed and discharged parallel to each other. Contact points are hardened and ground.

Two supports 43 (the second for simplicity is not shown) are fixed on hinges 44 (to ensure the convenience of work with the stand). In the case of measurements, the maximum possible gap must be set between the end face of the nozzle 45 and the end face of the adjusting bolt 46, to the changes of which the sensitive element will subsequently react (SF bellows - Figs. 2 and 3) (with a nozzle hole diameter of 2 mm, this gap equal to 0.5 mm).

In the case of measurements, this unit should be retracted along the rails 41 and 42, then the corners 40 should be summed up.

For convenience, the measuring unit of the device (Fig. 3) consists of four mutually isolated pneumatic chambers with dial indicators.

The vibration simulation unit contains (Fig. 9): an eccentric disk 37, rigidly mounted on the output shaft of the electric motor 38 which (if necessary) is installed on the basis of 1 device.

The stand works as follows.

In the initial position, the measuring and reference gaps of the pneumatic circuit (see Fig. 2) must be equal to each other, that is, S1 = S2 (i.e., the equilibrium state of the pneumatic circuit of the gauge type must be ensured).

The probe S1 and the measuring S2 have preliminary gaps set the gaps, respectively, between the ET reference surface (Figs. 2 and 3) and the elastic plate UE (in the range 0.1–0.2 mm).

Open the shut-off valve (pneumatic switch) of the air supply and compressed air at a pressure of 0.4-0.6 MPa from the compressor or industrial pneumatic network (Fig. 2) enters the filter-moisture separator PV, where it is cleaned and then enters the pressure reducing valve with pressure regulator RK, the setting of which sets the pressure at the outlet of it within 0.15-0.2 MPa, which is controlled by the pressure gauge M. Then the moving stream of compressed air is divided into two “branches”: the reference one through the throttle ДР1 and the measuring one through the throttle Др2.

Passing through these “branches”, two streams of compressed air simultaneously: get into the pneumatic chambers K1 and K2 (Fig. 2), act on the outer and inner surfaces of the bellows and, at the same time, are released into the atmosphere through the reference S1 and measurement S2 gaps formed by nozzles with the reference surface of the electromagnet and the elastic plate UP.

In the case of equal gaps S1 = S2, the SF bellows will be in a state of equilibrium (rest), since the pressure of the compressed air inside and outside the bellows will be the same (mutually balanced).

The BI indication unit (dial gauges) in contact with the loose end of the SF bellows should be set to zero. Thus, the circuit (Fig. 2 and 3) with four pneumatic channels is in equilibrium and is ready to implement measurements.

During measurements, the elastic plate of the UE is deformed and changes the size of the measuring gap S2 between the measuring nozzle of the IC and the first (i.e., the elastic plate of the UE), which leads to the pneumatic circuit leaving the equilibrium state (its imbalance occurs, since S1 ≠ S2).

The nozzle openings are perpendicular to the centers of symmetry of the surfaces of the plates, the latter are located at a distance of 50% of the length from each edge of the plates.

In this case, the air flow through the measuring IC and the reference ES of the nozzle changes (Fig. 2), 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 (Figs. 3 and 2) and, according to their degree movements, by visual counting of the signal from the display unit BI - it becomes possible to estimate the value of the mismatch (Fig. 3) for each of the four pneumatic channels. This is the principle of operation of the pneumatic circuit shown in FIG. 3.

The mounting plate 1 is fixed on the foundation in a horizontal position. The test bolt 12 is passed through the holes of the replaceable sleeves 8 and 9, and the nut 13 is screwed onto its threaded section until the stop. The support 1 is brought into contact between the nozzle 6 and the end face of the bolt 7. Set the gaps between the elastic elements and the pneumatic nozzles (except for the nozzle 6). Install a torque wrench or wrench working head, depending on the mode of operation of the stand.

Test mode of threaded connections (static).

From the torque wrench (or wrench), the moment is transmitted to the tested bolt 12 and is spent on overcoming the moments in the threaded coupling bolt - nut and on the end of the bolt 12.

The moment at the end M _{T of the} test bolt 12 during tightening occurs from the interaction of its support head and replaceable sleeve 8, is transmitted through an auxiliary sleeve 6, brackets 17 and 18 to the elastic elements 21 and 22, which are bent, change the gap between the plate and the pneumatic nozzle 31, thus forming a mismatch signal, which is fixed by one of the indicators of the clock type (hereinafter, the IF) of the measuring unit (Fig. 3).

The moment in the threaded joint M _p bolt – nut during tightening arises from the interaction of the threaded surfaces of the test bolt 12 and nut 13, is transmitted through an auxiliary sleeve 7, brackets 19 and 20 to the elastic elements 23 and 24, which bend, change the gap between the plate and the pneumatic nozzle 29, generating a mismatch signal, which is recorded by the second IF of the measuring unit (Fig. 3).

The total torque M _total when tightening is transmitted through the castellated sleeve 5 to the elastic elements 14 and 15, which are bent, change the gap between the plate and the pneumatic nozzle 30, forming an error signal, which is fixed by the third IF of the measuring unit (Fig. 3).

The elongation Δl of the test bolt 12 occurs by reducing the gap between the nozzle 6 and the bolt 7, and then is fixed by the fourth IF (Fig. 3).

The angle of rotation φ is recorded (Fig. 11) as the difference between the final and initial position of the rack 34 relative to the gear wheel 35 (gear engagement - the gear). Thus: the transmission gear wheel 35 - rack 34 (moving along the rails 36) allows you to judge the angle of rotation of the nut.

The obtained values of the moments in the thread and under the head of the bolt, the value of the applied torque, the elongation of the bolt and the angle of rotation φ of the nut give the full power characteristic of the tested threaded connection in statics.

Wrench setting mode (dynamic).

The test bolt 12, replaceable sleeves 8 and 9, as well as the nut 13 are replaced. A nutrunner is installed and the general switch is pressed. At the same time, they act simultaneously: the valve for supplying energy to the wrench, actuating the ring wrench, pneumatic sensors 6, 29, 30 and 31 (Fig. 4) that record the total torque, the moments in the threaded coupling bolt - nut and at the end of the bolt 12, and also the extension of the bolt 12.

Next, the wrench drive power is adjusted to the required tightening value according to the set values of the controlled parameters.

Mode of simulation of operational fluctuations.

The test bolt 12 (Fig. 9) is supported by the head on the replaceable sleeve 8, and the nut 13 on the replaceable sleeve 9, made of the same material and the same roughness as the actual threaded connection.

After completing the tightening process of the bolt 12 and the nut 13, the electric motor 38 is turned on (Fig. 9), as a result of the action of the eccentric 37 on the threaded connection, operational vibrations are simulated (in Fig. 1, the power unit 39 is shown schematically). As a result, the nut 13 can self-unscrew, the value of which can be judged by the angle of rotation of the gear 35 relative to the rack scale 34, graduated in degrees.

Practical use of the bench allows to increase the reliability of measurements of controlled parameters and to take into account the actual conditions for the implementation of the PC tightening process, including impact wrenches.

The scope of the stand extends to all types of wrenches, since the device’s design includes all known methods of tightening control for the range of metric threads M4 - M24.

Information sources

1. RF patent No. 2199099, MPK-7 G01L 3/14, G01L 5/24 Method of torque control and pneumatic device for its implementation // Lanshchikov A.V., Moiseev V.B., Trilissky V.O., Fedin S.V. Publ. - 02.20.03, Bull. - 5.

2. RF patent No. 2142616. A device for measuring and monitoring the tightening force of threaded joints, MPK-7 G01L 5/24, // Tolmachev S.M., Karpov A.P., Zhdanov O.N., dated 05.25.1998.

3. RF patent No. 2265810. A device for determining the tightening parameters of threaded joints, MPK-7 G01L 5/24, // Vorobei V.N., Izvolensky E.V., Yurchenko Yu.V., Podderegin A.V., dated 02.12.2002.

4. RF patent No. 2337336. Control and diagnostic stand, IPC G01L 5/24, // Lanshchikov A.V., Moiseev V.B., Volkov V, V., Seliverstov A.A., dated 07.11.2006.

5. Vysotsky A.V., Kurochkin A.P. Pneumatic means of measuring linear quantities in mechanical engineering. - M.: Mechanical Engineering, 1979. - 206 p.

Claims (3)

1. Pneumatic control and diagnostic stand, comprising a base, two brackets coaxially located and a stand mounted on the base with the possibility of longitudinally fixed movement, rotatably mounted in the respective brackets and spring loaded relative to the latter in the tangential direction of the elastic plates of the sleeve, designed to be placed in them test bolt with nut, mounted in a rack with the possibility of rotation of the drive shaft, designed to interact with the dynamo with anometric wrench or wrench, a rotation angle sensor associated with the drive shaft, a spanner designed to interact with the head of the test bolt, mounted on the base of the displacement sensor, designed to interact with the end of the threaded end of the tested bolt, characterized in that in order to expand technological capabilities and simplifying the design of the device, the sensors for detecting deformations of the elastic plates of the stand are made pneumatic (such as a nozzle-damper) and installed with a gap of 0.1-0.2 mm relative to relative to the surfaces of the plates, are located at a distance of 50% of the length from each edge of the plates, forming measuring branches of a differential pneumatic circuit of a manometric type, and the reference branches of this circuit are made in the form of a single measuring unit. 2. The stand according to claim 1, characterized in that the sensitive elements of the proposed differential pneumatic circuit of the manometric type are made in the form of bellows and placed in pneumatically isolated pneumatic chambers, respectively connected with the reference and measuring branches. 3. The stand according to claim 1, characterized in that the recording unit of the total (external) moment is made in the form of a power unit and is placed with the possibility of rotational movements around its axis in the inner ring of the bearing, and the outer ring of the latter is fixedly mounted relative to the base of the device.

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