EA008035B1 - Tyre air pressure control device - Google Patents

Abstract

The invention relates to instrument-making industry, in particular for use in transport industry. A pneumatic pressure control device comprises a sensor, mounted on a wheel rim with a sensitive element facing inside a tyre, a monitoring pressure device mounted in a passenger compartment and a transmitting device. Said transmitting device comprises a contact ring fixed on the working surface of a brake disk or a drum and separated therefrom, an electrical brush being in contact with said ring and arranged on a protective jacket of the brake disk or on the brake block and a connecting scheme. The proposed device is notable for higher operation reliability and safety and lesser tyre wear.

Description

Pneumatic tire pressure controller is an electromechanical device that belongs to the field of instrumentation and is intended for use in the automotive industry as an automatic signal device that monitors tire pressure and alarms when it falls below the permissible level.

The US Congress passed a law banning the operation of passenger cars without tire pressure monitoring systems since 2003 (“Driving” No. 6/2001, p. 54).

The degree of accident and driving danger when the pressure in the tires of vehicles is lower than established by the operating rules.

Pressure reduction from the norm, MPa Consequence 0.02 On dry asphalt the reunion in control becomes noticeable 0.05 The maximum allowable speed is reduced by 15 km / h, fuel consumption increases by 3-5%, the safe speed of hitting the curb is reduced by 20%, the aquaplaning threshold is reduced, the tire service life is reduced by 30% 0.1 Noise increases by 2 dB (A), (approximately 66%); Significant loss of controllability of the car, Destruction of the tire, disruption of the tire from the rim of the disk.

To combat the unauthorized reduction of the working pressure in the tires of vehicles and prevent accidents, to monitor and actively maintain the pressure in the tires, there are various technical solutions. For example, systems supporting tire pressure in wheels are known and used in military technology, such as “A device for supplying air from a fixed pin to a rotating hub” (No. 2019434, KN 2132283). But such systems are not advisable to use in serial automotive industry because of their structural complexity, high cost and lack of special operating conditions.

A device is known for dynamically controlling air pressure in a pneumatic tire of a vehicle (KN 2047115, IPC 6 O 01B 17/00). The essence of the invention lies in the fact that it contains two induction converters in the form of permanent magnets made with the possibility of installation on the respective wheels, and induction coils made with the possibility of installation on a fixed part of the vehicle and interacting with the corresponding magnets, as well as a processing and indication unit signals, including information LEDs, blocking diode, indicator LED, shunt resistor. A change in air pressure in the tires of the wheels is accompanied by a change in their radii and a corresponding change in rotational speeds. Information signals of the wheels, excited in the induction coils, are transmitted through the communication channel to the LEDs, which record the frequency of their rotation. The blocking diode protects the indicator LED, and the shunt resistor is selected so that the indicator LED lights up when the pulses coincide on the LEDs. By the frequency of the tanning indicator LED, you can judge the difference in air pressure in the corresponding pair of wheels.

A technical solution using the principle of a changing wheel radius has the following disadvantages.

Not taken into account the change in the radii of the wheels depending on the different loading of the vehicle and the unevenness of its location. It is not taken into account that the geometrical dimensions of the tires have a rather wide scatter, even in new ones, up to several millimeters, and the authors' calculation shows that a change in radius ΔΚ by 0.1 mm corresponds to a change in pressure ΔΡ by 0.1 kgf / cm ² (see KN 2047115), so the system is initially ready to issue an error.

The system will not work in the static state of the car (in the parking lot), as in the absence of movement there is no difference in the frequency of rotation of the wheels. Also, with equal flat tires, which most often happens when the tires do not pump up for a long time, this system will not work.

The closest to the invention, i.e. the prototype is “Device for dynamic control of air pressure in the pneumatic tire of a vehicle” (KN 2143345, IPC 6 V 60C 23/02, 1998).

The device comprises a cap that is screwed onto the tire valve instead of the standard cap, and a housing into the openings of which a sleeve with a head for pressing the valve spool rod is introduced with an air filter. Inside the housing there is a threshold pressure sensor with a membrane and a switching unit, as well as a passive transponder. At an operating pressure in the tire, the membrane has a deflection, the contact of the switching unit is closed, and the transponder receives radio frequency signals from the emitter installed on the basis of the vehicle. In the case of an unacceptable decrease in tire pressure, the membrane is straightened, the contact of the switching unit opens and the transponder ceases to give a response. The lack of response is recorded in the node receiving information and the driver receives an alarm.

The specified device has the following disadvantages. It is necessary to allocate to each wheel a certain frequency of the “code radio frequency transmission”, i.e. separate coding for the EC circuit each

- 1 008035 device with the installation on the basis of the vehicle for these purposes by a separate frequency generator, with appropriate decoding on the information receiving node and tuned to the resonance frequency of the LC circuits of the transponders, to exclude interference.

In the event of failure of any of the elements of the transmitting half-set (according to the terminology of the authors), i.e. device, it becomes necessary to completely replace it, because it cannot be repaired. As a result, it becomes necessary to select a new device for replacement, with the appropriate radio frequency parameters, which will be difficult to do.

Tuning the resonant frequencies of the LF circuits requires special equipment, qualifications, and this is with the proposed mass production.

The complexity of the device is comparable to a device for measuring, and a high accuracy class.

The device is not reliable and not durable, because has a frankly weak spot, namely the switching node. Unauthorized contact vibrations due to vibration, as well as disturbances or failure due to shock, deformation of the device body, oxidation of contacts (if they are not made of precious metals) are possible. The noise immunity of the device, including a passive transponder and an information receiving unit, is required (shielding). The fluctuations in the ambient temperature, which can be from -30 ° C in winter and up to + 30 ° C in summer, are not taken into account, and then tire pressure changes can reach 20-25% of the nominal.

Currently, the company “Beru” offers a pressure and air temperature sensor together with a radio transmitter operating at a frequency of 433 MHz, including a lithium-ion battery and mounted on a special valve, which is installed instead of the standard one. Leading automakers such as Mercedes-Benz, BMW, Renault, Volvo, etc. offer future car owners to pay about 500 US dollars for this system. In Russia, the specified amount is approximately 10% of the cost of a new car.

The objective of the invention is to develop a device for monitoring emergency pressure drop in a car tire in a static state and while the vehicle is in motion.

The device should be simple to manufacture and maintain, cheap, reliable and maintainable in the simplest conditions.

It should not imply significant changes and improvements to the existing designs of units and assemblies on mass-produced cars and could be installed in the conditions of a car service as additional equipment on cars manufactured before the introduction of the present invention into production.

The goal is achieved by applying the well-known principle of transmitting an electric signal from the fixed part of the electric machine - the stator to the rotating part - the rotor, using a rotating contact ring on the rotor and a stationary brush installed.

The novelty of the present invention, a significant sign of difference from the prototype is the lack of a complex radio transmission system, instead of which a transmitting device is used, consisting of a contact ring on the working surface of the brake disc or drum, an electrical brush located on the protective casing of the brake disc or on the brake shoe, and use instead a simple pressure sensor screwed onto the bus valve of the device, similar in design and operation to the emergency pressure sensor sla type MM-10D ZiM or 2101380600, which is inserted into the rim of the wheel, similar to valve tubeless tires.

Device description

The tire pressure pneumatic controller includes a pressure signal device 1, FIG. 1, installed in the passenger compartment in the form of a light signaling unit 6 made up of LEDs or light bulbs, and an additional audible alarm is possible 5. The pneumatic controller also includes a signal device sensor 2 mounted on the wheel rim.

The transmitting device consists of a contact ring 3, FIG. 1 mounted on the working surface of a brake disc or drum and an electrotechnical carbon-graphite or electro-graphite brush 4, FIG. 1 mounted on the brake disc guard or on the brake shoe.

The circuit provides the transmission of an electrical signal from sensor 2, FIG. 1, to the slip ring 3, and then through the brush 4 to the pressure signal device 1. The circuit is powered by the on-board voltage from the battery.

The device operates as follows.

Mounted on the rim of the wheel 7, FIG. 2, and the sensor of the signal device 2, which is included in the sensor element inside the tubeless bus 12, is configured to close the contacts, to the set threshold pressure value. It works when the pressure inside the tire decreases, i.e. closes the contacts and commutes the electrical circuit of the pneumatic controller when the tire pressure drops below the set value.

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Electric current from the terminal (+) through the pressure signal device 6, FIG. 1, through a signal light 1 through a wire connecting with a brush 4 through a contact ring 3, and an electric wire connecting with a sensor of a signal device 2 through a wheel rim, it goes to ground (-).

As a result, a warning light / sound is triggered.

The number of pneumatic controllers is determined by the number of wheels to be monitored. In the usual version, four sets are needed on four wheels, with a common sound alarm unit. In the diagram of FIG. 1 shows the conclusions of terminals A, B, C, D from the pressure signal device (light / sound signaling unit) with a common buzzer of the sound signal 5 to the sensors of the signal device of each wheel.

The invention can be illustrated by examples of specific implementation options based on commercially available components of the automotive industry.

Example 1

An example illustrates the design of a tire pressure pneumatic controller for a car with a front-wheel drive VAZ-21103, on the front wheel with disc brakes. The sensor signal device 2, FIG. 2, is hermetically mounted on the rim of the wheel 7, with a sensitive element inside the tire cavity 12 and is configured to operate at a pressure of 1.65 +/- 0.05 kgf / cm ² . From the sensor 2, inside the protective metal tube of small diameter 3-4 mm 13, the electric wire is led to the hub 8, through the plug 14 and then through the additionally made holes in the hub 8 and the landing end part of the brake disk 9 to the contact ring 3, which is installed on the inner working surface brake disc and isolated from it. Next, the signal is removed by an electrotechnical brush 4 mounted on the protective cover 10. From the brush, the signal through the wire through terminal “A” enters the alarm unit 6 to the pressure signal device 1 and the buzzer, FIG. one.

One of the technical solutions for supplying a signal from a sensor to a signal device is shown in FIG. 3, where 9 is a ventilated brake disc, 15 is a bushing, 16 is an electrical wire that leads to the contact ring 3 through the interdisk space of the ventilation ribs 17. The contact ring is in a groove on the inner working surface of the brake disk coaxially with its axis of rotation, glued and insulated from it using polyester, or phenol-formaldehyde polymers, or epoxy, or electrical insulating varnish 18.

In FIG. 4 shows the possible location of the brush.

A brush in the brush holder 4 is mounted on the protective casing 10 of the brake disc 9 by means of screws 19. The brush graphite is in contact with the contact ring 3. The contact ring periodically, during braking, is in contact with the brake shoe of the brake mechanism 20, due to which it is constantly in relatively clean condition, because it is cleaned of dirt and moisture during braking using friction pads.

From the brush, an electric signal is supplied to the pressure signal device, made in the form of an electric bulb or LED, for indication and additionally to the buzzer of the sound signaling unit, located in the vehicle interior in any convenient place. If the pressure drops inside one of the tires below the installed one, on which the pressure sensor is configured, the contacts in it close, a closed circuit appears, the corresponding lamp lights up, and this notifies the driver of a malfunction that occurred in a particular wheel. The steering knuckle of the front suspension of the car 21 in FIG. 2, 4 are indicated for a more complete representation of the relative positions of the elements.

Example 2

An example illustrates the arrangement of a pneumatic tire pressure controller for a VAZ21103 automobile on a rear wheel with a brake drum, and is indicated in FIG. 5.

The sensor signal device is mounted on the rim by a sensing element inside the tire cavity, analogously to example 1, as shown in FIG. 2. On the brake shoe 22, FIG. 5, a brush is installed in the brush holder 24 with screws and in contact with the slip ring 25, FIG. 6. The contact ring is located on the working surface of the brake drum 23. It is arranged and isolated from the brake drum in a specially made groove.

The brush is always in contact with the slip ring, regardless of the position of the shoe, as the brush spring in the brush holder constantly presses it. A hole for the brush is made in the block 22 and the friction lining for contact with the track of the slip ring. When the pressure drops below the set, the sensor of the signal device is activated and the circuit is switched. Through a wire passing through the brake drum housing, FIG. 6, brush 24, FIG. 5, and then again, via an electric wire, the signal enters the corresponding signal device.

Example 3

One of the elements of the present invention is a sensor signal device, which may be similar to an emergency pressure sensor, for example, type MM-120D ZiM or 2101-3810600, used as sensors for a warning lamp of oil pressure in the engine lubrication system. For the technical implementation of the invention, it is proposed, in one embodiment, to use a similar sensor, with possible changes in the design, overall dimensions and arrangement of the seat, according to the example indicated in the diagram of FIG. 7.

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The proposed sensor consists of:

- a metal case with a threaded part for mounting to a disk;

- a plastic cap;

- lock nut;

- sensor terminal;

- contact regulator;

- persistent spring;

- persistent cup;

- sealed contact plate;

- sensitive membrane;

- plastic rod.

Compressed air presses on the membrane 33, at a pressure higher than the set pressure, the resulting force exceeds the spring force 30, and the thrust cup 31 does not come into contact with the contact plate. When the pressure decreases, the plastic rod 34 is displaced by the spring, the contacts of the thrust cup 31 and the contact plate are closed. As a result, an electrical signal is supplied from the sensor terminal 28 to the housing 25, and the entire electrical circuit of the pneumatic controller is closed.

Due to the fact that the ambient temperature can vary from -30 ° C in winter to + 30 ° C in summer, changes in tire pressure occur, the difference of which can reach up to 25%. To eliminate the temperature factor and the resulting error, a control element is designed in the form of a contact regulator 29. If necessary, using a screwdriver and a slot provided in the end of the contact regulator, you can change the compression ratio of the thrust spring, and thereby adjust the sensor to the required pressure , in accordance with the changing temperature. Using the lock nut 27, this position can be locked. Adjustment can be made independently, controlling the sensor’s response according to the indications of a standard automobile pressure gauge worn on the wheel tire valve.

Modern requirements for traffic safety require a stable, trouble-free state of the main components and systems of the car. Chassis and wheels are critical elements of car safety. In particular, the condition of tires, the pressure in them directly affect the safety of traffic.

This invention allows to reduce tire wear, to ensure the stability of the car while driving, to avoid loss of transport control, tire destruction and, accordingly, accident. The device is easy to manufacture and install, reliable in operation and repair-capable, without the participation of special equipment and qualified personnel.

The device operates in a static and dynamic state, i.e. during parking and when driving.

Claims (4)

CLAIM 1. A pneumatic tire pressure controller including a signal device sensor mounted on the wheel rim with a sensing element inside the tire cavity, a pressure signal device installed in the passenger compartment for signaling, and a transmission device, characterized in that the transmission device consists of a contact ring mounted on the working surface of the brake disc or drum and an electrotechnical brush that is in contact with the contact ring and located on the protective zhuhe brake disc or the brake shoe, and circuit connections. 2. Tire pressure pneumatic controller according to claim 1, characterized in that the pressure warning device is a visual light and / or audible alarm device, consisting of light bulbs or LEDs and a buzzer, which turns on when the contacts in the sensor signal device are closed when the pressure decreases in the tire below the established. 3. The tire pressure pneumatic controller according to claim 1, characterized in that the signal device sensor is a membrane type device, the contacts of which are closed when the controlled tire pressure acting on the sensor membrane becomes less than the allowable critical value. 4. A tire pressure pneumatic controller according to claim 3, characterized in that the signal device sensor further comprises an adjustment device for setting a threshold value at which contact closure in the sensor occurs.