Device for automatic control of air pressure in the tires of the wheels of agricultural tractors
(57) Abstract:The invention relates to vehicles and can be used to control pressure in the pneumatic tires of a moving tractor. The device comprises a toothed disks mounted on the respective wheels, induction associated with measuring transducers of the angles of rotation of the tractor wheels. The signal processing unit transducers contains a comparator, the inputs of which are connected with the transducers through the serially connected inverters frequency - voltage, ramasadaya circuit and diodes. The comparator has two threshold condition and is covered by feedback with the possibility of changing the threshold. Converters frequency - voltage made with smooth regulation of transmission ratios. The output of the signal processing unit connected to the elements of sound and light alarm. The technical result of the invention is to improve the versatility and accuracy of the control pressure in the tires of agricultural tractors. 1 C.p. f-crystals, 1 Il. The invention relates to vehicles and can be used for pressure control in mon the class. 7 G 01 L 17/00, 1985) for monitoring the tire pressure of vehicles containing inductive transducers, mounted on wheels, an induction coil mounted on the fixed part of the vehicle, the processing unit and the indication signal, consisting of a counter, oscillator, logic elements and relays.It is also known device (patent RF 2047115, CL G 01 L 17/00, 1992) to control the air pressure in the tires of the wheels of vehicles, comprising two inductive transducer made with the possibility of installation on the respective wheels, and an induction coil mounted on the fixed part of the vehicle, and the processing unit and the indication signal is made in the form of series-connected first and second LEDs in parallel, which included led.Such devices have significant disadvantage in low-precision control tire pressure low-speed, low-speed vehicles and having different radii of the wheels.The technical result of the invention is to increase the versatility and accuracy of the control tire pressure especially slow"ptx2">This technical result is achieved in that the device for automatic control of air pressure in the tires of the wheels of agricultural tractors, including transducers angles of rotation of the tractor wheels attached to a fixed part of the tractor unit for processing signals, the output of which is connected with the elements of sound and light alarms, contains the toothed discs mounted on respective wheels of different radius of rotation, and the signal processing unit transducers rotation angles of the wheels of the tractor includes a comparator having two threshold condition and is covered by feedback with the possibility of changing the threshold of the comparator, the inputs of which are connected with the measuring transducers, respectively, through the serially connected inverters "frequency - voltage", made with smooth regulation of transmission ratios ramasadaya circuit and diodes. In addition, measuring transducers of the angles of rotation of the wheels is made in the form of induction elements with bias.Diagram of the device shown in the drawing) includes a toothed metal disk 1, the magnets 2, indexdata - the voltage connected to the comparator 8 with the two threshold States with feedback 9 to change the level of the threshold comparator 8. Transfer coefficients of the transducers 6 are adjustable (by changing the values of resistors 7) to compensate for the unbalance of the diameters of the small R1and big R2the radii of the wheels. To the output of the comparator 8 is connected to the luminous elements (e.g., LEDs) 10 and 11 audio alarms.The device operates as follows. During the rotation of the wheels and correspondingly toothed disk 1 (rigidly mounted on wheels) in the induction coils 3 induced electromotive force (EMF) in the form of short pulses with a period T of their sequence, is equal to T = 1/fc(fc- frequency pulses with induction coils 3, proportional to the frequency of rotation of the wheels). Because changing the air pressure in tires is accompanied by the change of their radii, then with a change in tire pressure will also change the speed of the respective wheels. Thus, the measurement of the difference of frequencies of rotation of the tractor wheels arising from the decrease in the radius of one of the two wheels, enables us to estimate the corresponding change in circuit 5 and the inverter 6 "frequency - voltage".At the same air pressure in pairs of wheels, the ratio of the frequencies f1(for wheels with small radius) and f2(for wheels with a large radius) is equal To= R2/R1. To achieve equal levels of output voltages of the converters 6 a gear ratio of one of them is set equal to K. In this case, the voltage level at the output of the comparator 8 will approach zero, so that the LEDs 10 will not emit light.When the reduction of pressure in one tire (for a specific pair of wheels) is the reduction of the radius of the corresponding wheel, which entails an increase in the frequency of its rotation relative to the other wheel (with rated pressure), and thus the output voltage of the converters 6 "frequency - voltage" will have different values, the difference which is proportional to the mismatch of frequency f1and f2*=KF2(refer to f1). At the output of the comparator considering the sign of the error to emit light one of the LEDs 10, indicating that the drop in tire pressure of the corresponding wheel.For measuring the differential pressure in the wheels by resno1(t1),2(t1- actual rotation angles of the first and second wheels at time t1;1(t0),2(t0- the initial angles of rotation of the wheel at time t=t0.Then the difference between the angles1(t1and2(t1) at time t1will be equal to
< / BR>The operation of integration of the difference frequency f1(t)-f2*(t) is a pair of wheels. If this
< / BR>the signs correspond to the cases when f1> f2or f2> f1respectively.Taking into account the expression for the speed of movement of the tractor Vmp= 2R1f1= 2R2f2where R1and R2the radii of various sizes of wheels, get
< / BR>where L is the path traveled during the time interval (t0-t1).The condition for the phase alignment of the provisions of the first and second wheels L[(R*2-R1)/R1R*2] = 2/K, where R2*=R1(Refer to R1the radius R2*).Assuming that R*2= R1+R when f1> f2and R*2= R1-R when f1< f2get
L[R/((R1R)R1)] = 2/to
L = [(2R1/kR)(2R1/k)].
Prilogy cord tires and to improve the working conditions of the driver, to determine the occurrence of inadmissible backlash, to determine the degree of slippage of the wheels. 1. Device for automatic control of air pressure in the tires of the wheels of the tractor, containing transducers angles of rotation of the tractor wheels attached to a fixed part of the tractor unit for processing signals, the output of which is connected with the elements of sound and light alarm, characterized in that it comprises a toothed disks mounted on the respective wheels, induction associated with measuring transducers of the angles of rotation of the tractor wheels, a signal processing unit which includes a comparator having two threshold condition and is covered by feedback with the possibility of changing the threshold of the comparator, the inputs of which are connected with the measuring converters respectively connected in series through the frequency converters-voltage, made with smooth regulation of transmission ratios ramasadaya circuit and diodes.2. The device under item 1, characterized in that the transducers of the angles of rotation of the wheels is made in the form of induction elements with bias.
FIELD: automotive industry; instrumentation engineering.
SUBSTANCE: proposed pneumocontroller includes sensor installed on wheel rim with sensing element inwards tire space, pressure indicator installed in vehicle and transmitting device. Transmitting device consists of contact ring installed on working surface of brake disk or drum, being insulated from drum, electric brush in contact with contact ring and arranged on protective cover of brake disk or on brake shoe and connecting circuit.
EFFECT: reduced wear of tires, improved stability and safety of vehicle on road.
4 cl, 7 dwg
FIELD: transport engineering.
SUBSTANCE: invention relates to automatic control of emergency situations on trackless vehicles, mainly heating and damage of vehicle tires. Proposed device contains magnetic circuits installed in tire uniformly over its circumference at least in two rows. Magnetic circuits of one of rows are made of ferromagnetic material with preset Curie point equal to maximum tolerable temperature of tire heating. Magnetic circuits of second row are reference ones, being made of ferromagnetic material with Curie point exceeding maximum tolerable temperature of tire heating. Electromagnetic sensors, AND-NOT gate, indicating unit are installed opposite to magnetic circuits of each row on structural members of track less vehicle at a distance from tire. Each electromagnetic sensors is provided with additional winding which is connected through corresponding switch to output of pulse generator, input of pulse generator being input of device.
EFFECT: provision of checking of device before beginning of movement and prevention of movement of vehicle if tire checking device is damaged.
2 cl, 1 dwg