JPS6125079B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic time fuse used in projectiles such as artillery shells.

The time fuses used in conventional artillery shells use either a mechanical clock mechanism or an electrical analog timer with a CR time constant.
In both cases, there is a limit to the accuracy of time measurement, and it was considered difficult to obtain an accuracy of 1% or more. In addition, since the time limit setting scale was analog and the time limit setting was done manually, there was a high possibility that errors would occur due to individual differences among the operators who set the time limits.

On the other hand, in order to improve timekeeping accuracy, a digital counting time fuze has been proposed in which the oscillation signal of a crystal oscillator is divided and counted, and the fuse is activated when a predetermined count value is reached. Although crystal oscillators generally have high precision, it takes a long time for the oscillation amplitude to grow and reach stable operation, so in the case of a timed fuze that operates after power is applied after the shell is fired, a startup error occurs during firing. Therefore, there was a problem that the timing error could not be reduced.

The present invention has been proposed in view of the above points, and is a digital time reference oscillator that is configured by cascading a crystal oscillator and a CR oscillator, and is capable of improving time accuracy by speeding up the rise time. The purpose is to provide a counting type electronic time fuse.

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the electrical circuit configuration of an electronic time fuse according to the present invention. In order to preset the time fuse at a predetermined detonation time, a dedicated time setting device externally supplies energy for driving the electronic circuit and a preset value signal corresponding to the detonation time from the signal input terminal 1. The discriminator 2 is for separating the driving energy and the preset value signal, and the driving energy is charged into a capacitor 3 and used as energy for driving the circuit thereafter. On the other hand, the value of the preset value signal is decoded by the decoder 4 and preset in the counter 11 as the starting time.
The preset counter value is then stored and held by the energy of the capacitor 3 until the fuse is fired.

In order to ensure the safety of the fuse, the internal power supply 5 is usually an injectable battery or a rotary generator that is inactive until the fuse is fired, but both power supplies are activated when the fuse is fired and the voltage increases. It takes some time to rise before inducing this. If the fuse timing start command is given at the rise of the internal power supply,
The rise time of the internal power supply mentioned above directly becomes the error in the detonation time of the fuse, so in order to compensate for this, a launch detection switch 6 is separately provided which operates using the centrifugal force caused by the rotation of the launch. The operating energy until the power rises is supplied from the capacitor 3 mentioned above to compensate for the time measurement error due to the time it takes for the internal power supply to rise. Since the internal power supply 5 and the capacitor 3 are coupled by the OR circuit 7, the higher voltage is applied to the crystal oscillator 8 and the CR oscillator 9, so that both oscillators are activated at the same time as firing.

The crystal oscillator 8 and the CR oscillator 9 are connected in cascade, and the latter has a circuit configuration in which forced synchronization is applied by the former. This is because crystal oscillators have good oscillation frequency stability, but the rise time is slow.
Since CR oscillators have contradictory advantages and disadvantages, such as poor oscillation frequency stability and fast rise time, both are connected in cascade to compensate for each other's disadvantages. In other words, the CR oscillator is intended to compensate for the rise time of the crystal oscillator. FIG. 2 shows an embodiment of both oscillator coupling.

That is, when a crystal oscillator starts up, there is some delay until the amplitude becomes steady, but there is almost no frequency fluctuation. To be more specific, in the process of growing the amplitude of the crystal oscillator, initially,
Since the CR oscillator does not sense it as an input, it oscillates with its own time constant. At this time, if the frequency of the CR oscillator is set to be almost the same as that of the crystal oscillator, then
Since the time is short, it does not affect the accuracy of the set time.

Next, before and after the input threshold of the CR oscillator is exceeded, the CR oscillator is dragged by the output of the crystal oscillator during this period, but the dragged frequency is originally accurate, so there is no problem.
In addition, the CR oscillator (which uses the logic shown in Figure 2) also functions as a kind of waveform shaping circuit, and in other words, the output of the crystal oscillator is used only for synchronization, so the amplitude It can be said that it is not affected by the disturbance of

The oscillator output is divided by frequency divider 10 to become a clock signal. The counter 11 counts down from the initial setting value for each clock signal, and finally reaches zero. The detector 12 detects that the counter 11 becomes zero and supplies an output to the AND circuit 13. The AND circuit 13 gate-controls the output of the detector 12 using the terminal voltage of the capacitor 3. This occurs if the timer fuse is not preset using the normal time setting device, or if an excessive amount of time has passed after the preset operation and the fuse is fired while the preset value on the counter has disappeared. The purpose is to prevent an accidental explosion of the fuse due to the uncertainty of the initial setting value of the counter.

The detonation circuit 14 detonates the fuse based on the output of the AND circuit 13. The detonation circuit is designed to operate when the counter indicates zero, but it is made inoperable for a certain period of time prior to detonation, that is, until the counter reaches a certain value or less, to further ensure the safety of the fuze. It is easily possible to do so.

As described above, the present invention provides a time reference oscillator in which a crystal oscillator and a CR oscillator are connected in cascade, and the oscillation frequency of the CR oscillator is forcibly synchronized with the oscillation frequency of the crystal oscillator, and the output of this oscillator. A frequency divider that divides the frequency, a counter that counts the output of this frequency division, a detector that detects when this count value reaches a certain value and activates the detonation circuit, and is activated by firing the fuse. An internal power supply, a capacitor as a power supply precharged by an external time setting device, a centrifugal force switch connected at one end to the capacitor and operated by rotation after firing the fuse, and the other end of the centrifugal force switch and the Since it is equipped with a CR circuit that connects either one of the internal power supplies to the time reference oscillator, (a) the time for activating the detonation circuit is digitally preset from the outside, so it is more accurate than the conventional analog type. can be dramatically improved.

(b) Since electric charge is stored inside the fuze from the outside in advance, it is possible to eliminate errors caused by delays in the rise of the internal power supply.

(c) It is possible to prevent an accident from occurring in the event that a bomb is launched with a preset count value changed prior to detonation.

(d) A time reference oscillator consisting of a crystal oscillator and a CR oscillator can dramatically improve the accuracy of time measurement.

It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an electronic time fuse of the present invention, and FIG. 2 shows an embodiment of a cascade synchronous coupling of a crystal oscillator and a CR oscillator. 3... Power supply charge capacitor, 6... Launch detection centrifugal force switch, 8... Crystal oscillator, 9... CR oscillator, 15... Synchronous coupling capacitor.

Claims (1)

[Claims] 1. A time reference oscillator configured to connect a crystal oscillator and a CR oscillator in cascade so that the oscillation frequency of the CR oscillator is forcibly synchronized with the oscillation frequency of the crystal oscillator, and the output of this time reference oscillator. A frequency divider that divides the frequency, a counter that counts the divided output of this frequency divider and can be preset from the outside, and a detonator circuit that detects when the count value of this counter reaches a constant value. an internal power source activated by the firing of the fuse; a capacitor as a power source precharged by an external time setting device; one end connected to the non-ground terminal of this capacitor; It is characterized by comprising a centrifugal force switch operated by rotation after launch, and an OR circuit connecting the other end of the centrifugal force switch and the higher voltage side of the internal power supply to the power supply terminal of the time reference oscillator. electronic time fuze. 2. The electronic time fuze according to claim 1, which is configured such that when the terminal voltage of the precharged capacitor attenuates below a certain level, the input gate circuit of the detonator circuit is closed and the detonator circuit becomes inoperable. .