SE435702B - WATCH FOR RETARDATION / ACCELERATION SENTENCE - Google Patents

Description

7ao4s7a-7 2 cheaper, but they require a certain relative rotational movement between the halves for the torque to be reached, which means a certain, though for certain uses of the guard acceptable, spread in the g- values, for which the guards must signal. _ For faokmarmenärdetbelænt attenvalctsskg-valueisazrínazxdmed use in vehicle brake control systems is defined by the starting point from the change in speed of the vehicle, which causes the rotational speed change in the flywheel in guards, for example according to Figs. 1 and 2 under the conditions when the guard emits a signal. The scissor band in between is v = r. w, where v is the vehicle speed, r is the wheel radius and w is the angular velocity the vehicle wheel. Furthermore, the fact that g = ground acceleration = 9.81 m / sec (average). High deceleration values then give high g-values and vice versa. Normal g-values for guards for vehicle bronchoscope control systems is usually between 0.7 and 1.5 g. Although thus many different couplings can be used, however, come in the following only guards equipped with magnetic couplings powder type on those based on magnetic hysteresis to be discussed race. Both of these mentioned coupling types must be considered so well known that only a summary description of their operating principles and characteristics should be desirable. They were used in many contexts both in the form of and which brakes. It is appropriate here to speak of "stator" and "rotor". It is furthermore suitable in view of the guard described here the construction, because the device function is the closest thing to consider as a coupling between an input shaft and a flywheel, to denote na device as a 'coupling fi The stator of the magnetic powder coupling consists of a mationation-magnetic i elements of iron with an inner cylindrical coupling surface. Its rotor remains also of a rotationally cylindrical element of iron, which is rotatable stored inside. the stator and includes an outer cylindrical coupling surface running with a small game or slot: root stator internal Connection surface. A solenoid is arranged so that the stator becomes an S-pole and the rotor one N-pole or vice versa. In the gap between the stator and the rotor there is one certain amount of magnetic powder which, under the influence of the magnetic field in the column, between the rotor and the stator is laid in strings between them and offers a resistance when the rotor is rotated relative to the stator, which 7804673- 7 Appropriate design of wkter can be made is the use of a viscose coupling, an eddy current coupling or different couplings of the type electric generator.

The stator 1 of the hysteresis coupling, which consists of an outer part 2, a inner part 3 and a solenoid 4, are supported in the guard housing (not shown) by bearings 5, 6. In the inner part 3 of the stator, an input shaft 7 is mounted in one needle bearing 8 and in a ball bearing 9. The hysteresis coupling rotor 10 is fixed connected to the ring gear 11 of a planetary gear 12. The hysteresis clutch rotor 10 and thus the ring wheel 11 is supported by the input shaft 7 above a ball bearing 13. In the one-piece with the input shaft 7 made the flange 14 is fitted with three pins 15, on which pins the plane gear 12 of the planetary gear three planet wheels 16 running. One end of a shaft 17 is designed as a toothed wheels, which constitute the 12 sun wheels of the planetary gear. The other end of the shaft is supported by a ball bearing 18, the outer ring of which is fixed in the guard house (not shown).

On the axle 17, the flywheel 19 is fixedly mounted. On statams l yttaraal 2 is that committee 20 is fixed, which committee carries two different sizes, opposing permanent magnets 21, 22, which are intended to activate a tongue element 23 with connections 24, 25. The projection 20 and thus the stator 1 can rotate about the longitudinal axis of the guard within a small angle, which is limited by the stop shown in the guard house (not shown). screws 26, 27. This angular movement is so adapted that if the stator is rotated in the direction of the arrow 28 against the action of a spring 29 until the movement is stopped against the stop screw 27 (which is shown mounted in a plate 70) so the tongue element 23 is closed, and if the stator is rotated in the opposite direction of the arrow 28 until the rotational movement is stopped by the screw 26, the tongue element breaks 23.

The working function of devices must now be described in more detail. At still- standing and at constant rotation in the direction of the arrow 28 the spring holds 29 the projection 20 against the set screw 26, the permanent magnets 21, 22 is in such a position in relation to that in the not the guard house attached to the tongue element 23, that this is broken that an amplifier 66 (see Fig. 4) is controlled to be power the solenoid 4 from the power source 65. The input the rotational movement of the shaft 7 is thus transmitted positively and without lag over the planetary gear 12 to the shaft 17 and thus to the flywheel 19.

If the input shaft 7 is subjected to an angular retardation hour as greater 7894673-'7 6 than that which, according to the laws of mechanics, corresponds to the torque from the spring 29 and the common moment of inertia of the flywheel 19, shaft 17 and co-rotating parts of the ball bearing 18 are thus overcome the tension in the spring 29, the projection 20 with the two permanent the magnets 21, 22 together with the stator 1 rotate in the arrow 28 direction to stop against the stop screw 27, the permanent magnets 21, 22 moves to such a position that the tongue element 23 closes and guides the amplifier 66 to cut off the current to the solenoid 4. This is released the rotor 10 of the hysterical coupling and thus the ring gear 11 free, why the stator 1 is no longer exposed to any torque from the rotor 10.

The spring 29 is then able to return the vacuum to the committee as a perennial magneterrza to the position of permanent magnet axis 21, 22, at which the tongue element 23 again breaks so that the amplifier 66 again for current r to the solenoid 4. A braking torque then occurs again between the rotor 10 and the stator 1 of the hysteresis coupling and about the input shaft 7 i is still exposed to an angle refractor hour that is greater than that if the inertia is determined for the flywheel 19 etc ööh the spring 29 so the tongue element 23 again breaks the current to the solenoid 4. The flywheel 19, the shaft 17, the ring gear 11, the rotor 10 and the planet gears 16 come on this way of being slowed down by an average moment conditioned by hystereskopplingerxs Inaxinxala Inoment and the small frilction moment that is exerted by the planetary gear 12, the ball bearings 18 and 13 etc in a high frequency "stick-slip" process This "stick-slip" process continues as long as the input shaft 7 decelerates with higher values than the guard's setting value, the resonant element 23 thus emits a high-frequency pulse current signal. Instead of the permanent magnet operated the tongue element 23 can of course be used as a standard microswitch. Experienced- However, the heat shows that the switch range shown here is the best.

To further shed light on the guard's working methods, please refer to the following a function description in connection with Fig. 4 which is a block diagram over one of many conceivable examples of an electrical connection for the elements included in a system according to the invention. At the guard's use for control of a vehicle's braking system is during normal driving or in the case of light braking, the tongue element 23 of the guard is broken, with no one voltage is on the control input arm of the solenoid circuit amplifier 66 and the holding circuit 67 of the braking force modulator 41 which both units are so 780-4673-7 The size of the resistor depends on the dimensions of the coupling and proportions, the amount of magnetic powder, etc. but scm for a certain cup ling is directly proportional to the field strength of the solenoid, ie of it applied current. The torque is also largely independent of the speed the number.

The magnetic powder coupling can provide large torques despite small external dimensions. and low power consumption, which is a clear advantage in this manhang but it has the disadvantage of cbörx hearing to be exposed to one some wear. However, the magnetic powder coupling is for some guards likaticzner very länplig.

In a hysteresis coupling, the rotor generally consists of a drum or more unusual a flat disk of magnetizable material. In the following only drum-type hysteresis couplings shall be described. The principled the function is the same for both types. There are several manufacturers of drum-type hysterical couplings, of which the most famous is probably known American company MAGTROL. Drummanihar has only one gable, in which one shaft is attached. The shaft is concentric with the drum. The stator consists of an outer and an inner part. The outer one is ring-shaped and is mounted con- centrally with the rotor. The interior consists of a cylinder which is likewise mounted concentrically with the drum. Through the inner part there is one central hole, through which the tma axis passes. The inner stator part irmehål- generally also the bearing of the rotor shaft. In the inner part of the outer part and the: The outer surface of the inner part is occupied by the same number of longitudinal grooves.

The two stator parts are mounted so that the grooves are offset by half a part. ning in verhåuarae to each other. between the tracks is formed in this way booms, the tops of which consist of narrow cylindrical mantle surfaces, which close close to the inner and outer mantle surface of the drum. The two stator parts can be magnetized by means of a solenoid so that the outer becomes S-pole and the inner N-pole or vice versa, which means that the rotor can be said be surrounded by a number of magnetic poles oda that it is coated on the inside of the same number of opposite poles, shot al half division. Hereby the magnetic the rotor is made according to a certain pattern and when the rotor is turned, this must be done patterns are shifted in the mass of the engine. This constant re-magnetization takes place with a loss, a so-called hysteresis loss, and it is this loss that is origin of the nominee.

The torque is speed independent and has full value from iían4s73-1 stationary. The only thing besides air clouds and stock losses, which for connections of the current order and speed are negligible. ra, which disturbs the speed dependence is an inevitable eddy current loss.

Through appropriate constructive design of the coupling in its entirety and choice of material in the drum, this non-linear part of the total moment kept below 1% of the total torque. For a certain coupling figuration, the moment is proportional to the stator magnetization, ie directly proportional note the current strength of the solenoid.

It should be noted that both magnetic powder couplings and hysteresis couplings must be fed over a temperature coke-expanded constant current circuit. unit if the torque is to be kept constant despite varying of the solenoids, the resistance of which varies with varying rer. A constant current generator can also prove itself therefore that the power source, such as the battery-generator system in a vehicle, does not keeps constant voltage.

A presently preferred embodiment will hereinafter be as follows is described in more detail with reference to the accompanying drawings, where Fig. 1 in perspective view shows the guard according to a present preference. gen embodiment, Fig. 2 in vertical section illustrates a cross section through the guard according to Fig. 1, Fig. 3 schematically illustrates an appropriate application, 7 Fig. 4 is a block diagram of a typical device where the invention included, and Fig. 5 is a diagram showing the relationship between certain indicated speeds as well as the signals that are then emitted partly from the guard's tongue emerald and partly to the brake shaft modulator and the time during the different periods for the process shown in the diagram. I I the guard illustrated in Figs. 1 and 2 is provided with hysteresis and the constructive description below will be done with reference to such a guard. It is easily realized with the guidance of what as stated above regarding magnetic powder and hysteresis couplings that it constructive design of a guard according to the lip firn förs ngen provided with magnetic powder coupling becomes largely identical to that on. ritnjngs- Figures 1 and 2 show the guard with hysteresis coupling. Led by what is illustrated in Figs. 1 and 2, the person skilled in the art will realize how 7 $ I fl46 73- 7 designed that in the event of a broken tongue element 23 the guard's solerxoid 4 receives current over the constant current assembly 68 while the braking force modulator 41 not powered by electricity. If the limit value is exceeded, the retardation value is overcome the tension in the spring 29, the stator 1 and the projection 20 with permafrost The magnetic magnets 21, 22 are rotated so that the permanent magnets close the guard tongue element, the control input of the holding circuit 67 and thus the control the time of amplifier 63 is energized. This cuts off the power the guard's solenoid 4 so that the braking device releases the planetary gear 12 ring gear ll free at the same time as the braking force modulator 41 is powered. So as soon as the ring gear 11 of the planetary gear 12 is released, the spring 29 returns the shot 20 together with the stator 1 and the permanent magnets 21, 22 to the position where the tongue element 23 again breaks, whereby the braking device again the free rotation of the ring gear ll stops. The power supply to the brake however, the power modulator 41 does not stop momentarily but is delayed one short time (see diagram fig 5). If, then the brake device braked up ring wheel 11, the: input shaft 7 still decelerates with values which is above the limit retardation value (the g- value) the voltage in the spring 29 is overcome again whereby the stator 1 with the projection 20 and the permanent magnets 21, 22 rotate so that the magnet element 21, 22 again closes the tongue element 23 and the cycle repairs in this way until the input shaft 7 ceases to tarder with values that are above the adjusted g-value. Frequency then for performed guards are usually between 40 and 100 Hz. This cup- schedule is based on the tongue element at initial activation closes. You can of course just as easily make an electric merging fl comlizag which is based on the tongue element at initial activation instead broken.

In the diagram according to Fig. 5, three curves are marked at the bottom vehicle speed, partly the flywheel average speed and partly the vehicle wheel speed in relation to the time exceeds a deceleration races and at the top of the figure are marked for corresponding time periods the signal for the signal emitted from the guard to the modulator (the upper line), partly the appearance of the signal emitted from the tongue element to the holding circuit (the bottom line). In the diagram (Fig. 5) shown the intermittent signal from the tuung element has been marked with At shortest time delay that the holding circuit must cause to 73 0-46-73 * 7 8 provide a continuous signal to control the current to the brake the force regulator during the entire time that the input shaft decelerates with higher values than the set limit value. With the peace verses, 40 - 100 Hz, which are as usual common for guards according to this invention one or a few hundredths of a second is generally sufficient for attgåstaæarna this.

The retention of the flywheel is certainly determined by its inertia. torque, maximum torque of hysteresis couplings, residual friction ment etc but in the spring 29 has the decisive influence, and one can therefore control the so-called "g" values of the guard by varying the voltage in the same.

The angular deceleration of the guard flywheel 19 is represented by the slope (derivative) of the lines in Fig. 5 showing the flywheel velocity. MAN says that high deceleration values correspond to high g-values and vice versa. When guarding a certain ford, one must clear oneself with a compromise so that you get acceptable stability and fairness optimal braking distances at all existing load and road friction conditions conditions if the g-values can not be controlled in any way with appropriate parameters. _ The preferred coupling constructions in the guards described herein are such that they allow easy ways to control the g-values of the guards.

The two most important variables that should influence the guards' values for a particular vehicle are partly how it is loaded and partly which the friction retainer that prevails between the wheel and the road surface.

Fig. 3 shows how these two variables can affect a guard's setting ning. In Fig. 3, a source of a pressurized medium, usually crude oil or compressed air, and 41 is a brake pressure modulator.

Line 42 connects the pressure source 40 to the modulator 41 and the line 43 for the pressure on to a wheel brake cylinder 62 for the brake to the vehicle wheel 44. Through a line 45 the modulated., or if the brake control system is not working, the unmodulated brake control to a cylinder 46 containing a piston 47 with piston rod 48 and return spring 49. The piston rod 48 affects the tension in the guard's spring 29. Cy- line 46 can run axially along two guide guides 52, 53. at wheel alignment 44 shaft, one end of a lever 54 is hingedly attached. The lever 54 is articulated on a pin 56, which is fixed in the vehicle's chassis 57. vsorlsva- 1 The other end 58 of the lever is hingedly attached to the inner cable of a Bowden cable 59. The other end of the inner cable of the Bowdexy cable is fixed in the the relief 46 in an ear 60 on the cylinder 46. The outer part of The outer sheath of the bowder cable 59 is attached at one end to the chassis in the vicinity of the body. of one end 58 of the lever 54. The outer sheath of the Bowden cable 59 the other end is attached to the means which are present and in a suitable manner attaches the two guides 52, 53 to the vehicle.

The brake fluid pressure sensing part of the system will now described in more detail. When no pressure is conducted from the pressure source 40 across the nodular tower 41 to the brake cylinder to the wheel 44 and thus not to cylinder 46, ie when not braking, the return spring 49 pushes the piston 47 fully to the right of the figure, so that the piston rod 48 holds the spring 29 one end in a low voltage mode, which in turn corresponds to one low g-value of the guard. When braking, the fluid pressure in the cylinder rises 46 and the force on the piston 47 the tension in the spring 49. wherein the piston 47 and its piston rod 48 begin to move to the left, whereby one end of the spring 29 is moved to the left in Fig. 3 corresponding to lower g-values in the guard. With further increased pressure, a point is eventually reached then the wheel tends to lock, so the guard signals to the nnodulator to lower the brake pressure. The brake pressure at which the guard begins to signal is a measure of the frictional conditions that prevail between njul- ooh roadway ooh the system has thus set the guard on a for the prevailing conditions appropriate g-value. This way of varying guards' g-values are sufficient for vehicles where the wheel pressure varies moderate with how the vehicle is loaded, eg heavy cars. On small light passenger cars, however, the wheel pressures vary considerably depending on how many people are in the car and how much luggage carried. For many trucks, these variations are very accentuated.

There are trucks where the zero clearance is four times as large when it is loaded as when it is unloaded. On such vehicles one can increase the effectiveness and versatility of brake control systems significantly if one also utilizes the way in which the vehicle is loaded as steering gear for the guards' g-values. The more one loads the vehicle wheel 44 in Fig. 3 however, the support spring 61 collapses. With increased load, the lever rotates 54 counterclockwise around the pin 56. Thereby the inner cable of the Bowder cable is pulled off one end 58 of the lever 54 downwards, the other of the inner cable 7 80467397 10 end, which is ñst in the ear 60 of the cylinder 46, pulls the cylinder 46 to the left in Fig. 3 wherein, provided that the piston 47 is stationary in. the cylinder. 46, one end of the spring 29 is moved to the left in Fig. 3 higher guard g-value It can be said that the load-dependent g-value The ion is superimposed on the fluid pressure dependent g-value adjustment.

For compressed air braking systems, braking force modulation systems are developed in which one does not lnodulate air clearance but allows a hydraulic system counteract the braking force exerted by the "normal" compressed air brorrssystexnet, so-called mtkraftxnodulation system. An example is reported in Swedish Patent Specification No. 75 Ol883-8. For such modulation systems it is readily appreciated that the cylinder arm length with the cylinder 46, the piston 47, The piston rod 48 and the return spring 49 in Fig. 3 are to be replaced with a ferenrtialtryàcylillderarrangenlang in which constantly the entire wheelcylirl- 62 applied air pressure as well. the right of the piston 47 is constantly applied side and the "opposing" Ilydraul pressure is constantly applied to the piston 47 left side. about the trymon advice for the 'normal braking air triolate ooh the "counteracting" hydraulic pressure is of different magnitudes, the The tialtryocoylinar consists of two different chairs fixed to each other. pistons with a vented space in between in a cylinder with two different diameters corresponding to the two piston diameters. Usually it is' end-to-end grazing "hydraulic pressure higher than the" horizontal "braking air pressure, why the piston scm of the bronze air pressure is the larger.

Those skilled in the art will recognize that various variations and modifications tion can be made within the basic idea of the inventor as defined in the attached patent pianos. any type of electric or on otherwise manoeuvrable coupling can thus be used in in accordance with the present invention if it meets the other criteria which is placed on the coupling in this assembly.

Claims (3)

våsï fl vßevffvs- 7 ll PATFNTKRAV Guard according to one or more of Claims 1 to 5 of Swedish Patent No. 77 12342-0, characterized in that the coupling consists of a magnetic powder coupling, an eddy current coupling, a viscous coupling, a coupling operating on the basis of magnetic hysteresis or any type of electric generator, wherein when the coupling is a magnetic powder coupling or of the type based on magnetic hysteresis, the electrically supplied solenoid (4) included in the guard during normal operation is continuously powered but in the activated state generates and the guard (1) supplies the solenoid (4) with high-frequency intermittent current, which is further converted by a compensating device (67) into a continuous signal, which is fed to the braking force modulator (41). Guard according to claim 1, characterized in that the solenoid (4) for producing temperature inertia is fed over a constant current unit (68). Guard according to claim 2, characterized in that the guard (1) g value setting is adjustable depending on the applied brake fluid pressure or at the compressed air system different 'pressure when used in grain operation with brake force modulation system of "counter force type" and / or applied vehicle load, where the g-value setting is effected by actuating a spring (29) for changing the spring force which determines the guard's g-value setting.