RU43365U1 - DYNAMIC RESEARCH STAND WITH RUNNING DRUMS - Google Patents

Abstract

The utility model relates to devices used in the experimental design work (R&D) during research and development of wheeled vehicles, in particular automobiles. In a well-known dynamic research bench installed in a semi-anechoic chamber with running drums driven by a direct current machine, a non-contact space-limiting vehicle positioning system is used on the bench, consisting of four self-contained protective actuators installed with a small gap relative to the outer surfaces of the body thresholds both sides of the car in the grooved guides of the stand; each of the actuating elements contains a limit switch, preloaded elastically suspended by a lever. At the end of the lever, a guide sleeve is mounted with a “lead” inserted into it, the free end of which is located under the threshold of the vehicle under investigation and is made at an angle to the horizontal plane, mainly 30 ... 45 °, while the details of the actuating element are mounted in a single housing with a removable a cover mounted on a tubular rack with the ability to adjust the position of the housing and the "leash" in height, the limit switches are connected in series to the electrical circuit through quick disconnect connections and connected to standard emergency stop system. The proposed dynamic research bench with running drums prevents the emergency operation of the bench and can significantly increase the level of safety of the car test process on a dynamic bench.

Description

The utility model relates to devices used in the experimental design work (R&D) during research and development of wheeled vehicles, in particular automobiles.

During bench tests, for example, to study noise, as well as to determine the power and economic characteristics of a car in a semi-anechoic acoustic chamber on a dynamic bench with running drums, a special car fastening system is used to keep the car from its spatial movements (hereinafter referred to as the fastening system). Known mounting systems, as a rule, are, in particular, a set of holding flexible cables with a tension mechanism in the form of four electric winches installed under the camera floor in the room of the engine room of the test chamber. A car mounted on a dynamic stand, in this case, is fixed by cables to towing hooks (eyes, hooks). Cables, performing the function of tensioning elements, are installed on the drums of the winches through the original fastening racks and the swivel plates of the stand winches mounted on the floor. The known system for securing a car and methods for installing a car on a stand does not ensure the safety of the test process in the event of spontaneous weakening of the tensile force (excessive deformation or break) of one of the fastening cables arising from high traction moments on wheels and high speeds of rotation of the drums. When one of the fastening cables loosens (excessive deformation, breakage), lateral withdrawal of the car immediately occurs, which can lead to loss of stability of the test object on the running drums of the stand and, as a result, damage to both the car itself and the expensive equipment of the dynamic stand. In addition, this problem is associated with the safe working conditions of the operators involved in the process of testing the car. Operator located in the cabin of the subject

the car, in the event of an emergency in the form of a weakening (break) of the mounting cable, is not insured against injury.

From the application DE 19916699 A1, IPC G 01 M 17/00, publ. 11/30/2000, the applicant F. AUDI AG, is known a holding device for bench tests of cars on running drums, which provides a fixed position of the car on the running drums, excluding it both longitudinal and lateral displacements, which is achieved through the use of rigid longitudinal and transverse couplers, containing threaded adjusting inserts, rods with a screw part and locking assemblies with swivel joints. The hinge thrust housings are rigidly mounted in the floor structure of the test room in which the stand is located. The disadvantage of this design is the use of rigid (without compliant elastic and damping elements) restrictive connections between, in particular, the vibrating body (body) of the car and the chamber floor, distorting the vibro-acoustic characteristics of the body, which is undesirable for their use in acoustic semi-anechoic test chambers. In this case, the dynamic excitation (vibration) from the power frame of the body, the elements of the car’s undercarriage is transmitted from the towing hooks through the vibration-conducting elements of the restrictive fastening connections to the camera floor, causing, in turn, its dynamic excitation (vibration) and the corresponding spurious noise radiation, distorting the real acoustic field of the investigated object (car). On the other hand, the imposition of rigid force-limiting constraints and their effect on the power frame of the body distorts the real vibro-acoustic characteristics of the body, which is undesirable when conducting high-quality vibro-acoustic studies of a car in an acoustic chamber equipped with running drums. In addition, the absence of flexible damping links in the structure of restrictive bonds does not allow for the following compensating maintenance of a constant effort to keep the car on the bench (tracking reaction) in unsteady test modes (acceleration, braking) of the car, which often leads to the appearance of additional impulse loads, like the test vehicle, and on the elements of the vehicle mounting device on the stand, which is ultimately associated with a change in the vibro-acoustic characteristics of the test The object (car).

In US patent No. 3520180, IPC G 01 M 7/00, 17/04, publ. 07/14/1970, a system for mounting a car on a dynamic stand with running drums is described, containing, in particular, six racks with electric winches, kinematically

connected by means of flexible elements (cable extensions) to the car body. The racks are designed to eliminate the vertical component of the power load from the fastening system due to the horizontal installation of the branches of the fasteners (cables), closing the vertical blocks with the towing hooks of the car (one rack located at the front and rear of the car) and to eliminate the lateral removal of the car for two pairs of racks - located to the right and left of the car body in the areas of the front and rear bumpers, designed to exclude the lateral withdrawal of the car. The latter are located in the areas of the planes of the front and rear bumpers of the car, i.e. in areas of direct direct sound emission by tires, the engine compartment and the exhaust pipe cut (in the planes of the bumpers). This creates additional sound-reflecting effects from the massive surfaces of the racks and distortion of the real sound field of a moving car on a motorway, which is undesirable for high-quality objective measurements of the external and internal noise of the car in an acoustic semi-anechoic chamber with running drums on which the car under study is mounted. On the other hand, such a system for fastening a car to a drum stand requires the use of a large number of expensive links for adjusting the cable tension - six electric winches with corresponding braking devices.

A known system for mounting a car on a dynamic bench with running drums, described in the certificate for a utility model of the Russian Federation No. 23503, MPK7 G 01 M 17/00, publ. 06/20/2002, BI No. 17. A known system for mounting a car on a dynamic stand with running drums, comprising a vehicle mounted on running drums, equipped with towing hooks front and rear, the spatial movement of which is limited by holding flexible elements fixed in mounting devices mounted on the floor of the stand, made in the form of two pairs of fixed vertical rotary racks located in pairs relative to the front and rear parts of the car body, and one pair of movable in the direction of the axis of the car racks; fixed vertical rotary racks are equipped with blocks rotating in horizontally located axes, and the axes of the blocks are mounted with the possibility of selective sampling and fixing along the height of the rack; movable racks are mounted in front of the car, in groove rails, the distance between which exceeds the width of the car body, with the possibility of selective

installation and rigid fixation and are equipped with blocks rotating in the vertical axes, and the blocks have the possibility of a fixed movement along the height of the rack; branches of flexible elements are fixed in front and behind the car to a single towing hook; movable racks are located between the towing hook and the stationary racks, so that the branches of the flexible elements form an obtuse angle with the apex in the vertical axis of the movable rack block. The disadvantage of this car fastening system is the lack of safety restrictive elements that impede and prevent the further development of lateral withdrawal (lateral displacement) of the car in case of spontaneous weakening of the tensile force (excessive deformation or break) of one of the fastening cables at high drum speeds, which can lead to emergency during the test. In addition, the absence of protective fences in the area of rotating running drums adversely affects the safety of working conditions of the stand operators, increases the risk of accidental access of the tester to rotating surfaces, which is unacceptable from the point of view of labor protection.

These shortcomings are eliminated in the design of a dynamic stand with running drums, presented in the utility model certificate of the Russian Federation No. 28772, publ. 04/10/2003, Bull. No. 10, accepted as a PROTOTYPE. In the well-known dynamic stand with running drums, an additional protective device is used in the form of a rigid sound-transparent mesh fence, which can be purposefully moved and fixed in front of the rotating wheels of the car, depending on its specific base, while the protective device contains a persistent limit roller purposefully moving and fixed in the necessary position depending on the track of the test vehicle, and preventing the development of lateral drive silt (lateral displacement) in case of spontaneous weakening of the tension force (excessive deformation, break) of one of the cables. The disadvantage of this design of a dynamic stand with running drums can be additional noise radiation that occurs in the case of periodic or constant contact of the rotating wheels of the car with the surface of the thrust restrictive rollers, which negatively affects the accuracy and reliability of acoustic studies of the car installed in the anechoic chamber on the running drums of the dynamic stand. Additional spurious noise emission is caused as a contact zone during rotation of the thrust bearing assembly

a roller with a side surface of the tire, as well as the transmission of dynamic excitation from the power carcass of the body, elements of the car’s chassis through vibroconductive elements of restrictive rollers to the chamber floor, causing its dynamic excitation (vibration) and the corresponding spurious noise radiation, distorting the real acoustic field of the studied object (car ) Also, the protective device implemented in the design of a dynamic stand with running drums with persistent restrictive rollers is not acceptable, for example, in the study of traction and economic characteristics of a car due to an unpredictable increase in tire rolling resistance.

The essence of the utility model consists in the fact that in the well-known dynamic research bench installed in the semi-anechoic chamber with running drums driven by a direct current machine, a system of contactless space-limiting vehicle positioning on the stand is used, consisting of four autonomous protective actuators installed with a small a gap relative to the outer surfaces of the thresholds of the body, on both sides of the car, in the grooved guides of the stand; each of the actuating elements contains a limit switch, preloaded elastically suspended by a lever. At the end of the lever, a guide sleeve is mounted with a “lead” inserted into it, the free end of which is located below the threshold of the vehicle under study, while the actuator elements are mounted in a single housing with a removable cover mounted on a tubular stand with the possibility of adjusting the position of the housing and the “lead” in height, the limit switches are connected in series to the electric circuit via quick disconnect connections and are connected to the standard stand emergency stop system. The essence of the utility model is illustrated in the drawings.

Figure 1 shows the dynamic research bench claimed as a utility model with running drums with a test vehicle mounted on it (front view).

Figure 2 shows a top view of the inventive dynamic stand with running drums.

The positions in figure 1-2 indicated:

1 - semi-anechoic acoustic chamber;

2 - sound-absorbing backstage of the acoustic chamber;

3 - floor semi-anechoic acoustic chamber;

4 - spring concrete shell of the chamber and the base of the stand;

5 - running drums of the stand;

6 - groove guide elements of the stand;

7 - test vehicle;

8 - fixing cable;

9 - DC machine;

10 - autonomous protective actuating element of a vehicle positioning system on a stand.

Figure 3 presents a fragment of the design of a dynamic research stand with running drums, containing a stand-alone protective actuator assembly (front view).

Figure 4 presents a top view of a self-contained protective actuating element.

Figure 5 shows the housing of a self-contained protective actuating element with a dismantled cover.

Figure 6 presents a schematic electrical diagram of the connection of the limit switches autonomous protective actuating elements.

The self-contained protective actuating element (hereinafter referred to as the actuating element, see Figs. 3-5) is a prefabricated structure including a housing 11 made, for example, of sheet steel or ABS, which is closed by a removable cover 12, which is fixed to the housing by set screws 13. In the lower part of the body mounted lever 14, made of a steel tube of rectangular profile. One end of the lever 14 is mounted on the housing 11 with a bolt 15, which is the axis of rotation of the lever, the opposite end of the lever 14 is resiliently suspended on the spring 16, while pressing the limit switch 17 of the limit switch 18 (for example, type MP1101LUHL3). At the end of the lever, from the side of the resiliently suspended end, a guide sleeve 19 is mounted into which a “lead” 20 is inserted, made of, for example, a steel bar. The free, cantilever part of the “leash” is made at a certain angle (3 (mainly 30 ... 45 °) to the horizontal plane. The housing 11 of the actuating element is mounted on a tubular support column 21 having a groove 22 for fixed movement and mounting of the housing 11 with using the clamping screw 23. Thanks to the grooved mounting system of the housing 11, the latter has the ability to move and lock in the required position so that the "leash" 20 of the actuator is located directly close to rum (2-3 cm) from the surface of the threshold

investigated car body. The base 24 of the support rack 21 is bolted 25 to the standard groove guides of the stand 6, which allows the actuator 10 to move along the car, i.e. vary your spatial location depending on the base of the investigated object. Limit switches 18 are interconnected in series in an electric circuit via quick disconnect connections 26 and connected to a standard emergency stop button of stand 27 (for the connection diagram, see Fig. 6).

Actuators 10 are installed on both sides of the test vehicle, for example, in the area of the front and rear mudguards in such a way that the inclined part of the “leash” is near the threshold of the car, with a small clearance set as a rule, which is acceptable for safety test conditions, usually 20 ... 25 mm. When weakening the tension force of, for example, one of the fastening cables, and the occurrence of lateral pull-off of the car on the rotating surfaces of the running drums, the surface of the threshold of the car body contacts the “leash” 20 of the actuator, causing the “leash” to deviate from its original position and, accordingly, the movement of the lever 14. Due to the movement of the lever 14, the limit switch 17 is pressed out of the limit switch 18, and, accordingly, the electrical circuit is opened in the standard alarm system stop the stand. When the emergency stop of the stand is triggered, the DC machine is braked to a stop with maximum torque. After that, the DC machine is de-energized, the ignition of the internal combustion engine of the vehicle under investigation is interrupted. Thus, the process of emergency operation of the stand is prevented with the identification and elimination of the causes of lateral withdrawal of the car on the stand.

The proposed dynamic research bench with running drums can significantly increase the level of safety of the car test process on a dynamic bench, and also eliminates the negative influence of extraneous noise signals caused by the use of persistent restrictive rollers in the protective devices of the bench on the results of acoustic research in a semi-anechoic chamber.

Claims (1)

1. A dynamic research stand with running drums driven by a direct current machine, comprising a vehicle mounted on running drums, equipped with towing hooks at the front and rear, the spatial movement of which is limited by holding flexible elements fixed in fixing devices mounted on the floor of the stand, characterized in that the stand is additionally equipped with a non-contact system limiting the space positioning of the car on the stand, consisting of four x autonomous protective actuators mounted with clearance relative to the exterior surfaces bodywork sill, on either side of the vehicle in the slotted guide stand; each of the actuating elements contains a limit switch, preloaded elastically suspended by a lever; in the end of the lever, a guide sleeve is mounted with a “lead” inserted into it, the free end of which is located under the threshold of the vehicle under investigation and is made at an angle to the horizontal plane, mainly 30 ... 45 °, while the details of the actuating element are mounted in a single housing with a removable a cover mounted on a tubular rack with the ability to adjust the position of the housing and the "leash" in height, the limit switches are connected in series to the electric circuit through quick disconnect connections and connected to the factory system emergency stop bench.