JPH0125630Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an automatic roll gap adjustment device that maintains and controls a preset demolition rate while detecting fluctuations in the load current of a motor.

[Technical background of the invention and its problems]

Conventionally, this type of hulling machine prevents changes in the dehulling state due to changes in the amount of paddy supplied or fluctuations in the roll gap caused by roll wear, etc., and maintains a preset dehulling rate to achieve a significant dehulling rate. It is necessary to suppress unevenness in the hulls, and automatic roller gap adjustment devices are now being installed. The appropriate theoretical load current value determined for the supply amount and predetermined demolition rate is determined, compared with the load current value of the actually operating motor, and the roll gap is adjusted according to the magnitude relationship. have been proposed, for example,
A typical control device is known from No. 58-114742.

In general, in this type of automatic adjustment device, error correction of the roll gap is performed by electronic control that compares a predetermined theoretical load current value with an actual load current value, so it is said that a stable demolition rate can be maintained. There are advantages.

However, since it is easy to compare such current values as a voltage comparison after current-voltage conversion, a configuration is adopted in which the magnitude of each corresponding voltage is compared using a comparator, but the difference between the detected value and the theoretical value is If the roll gap adjustment mechanism is activated only by determining the size,
Since it is almost impossible to completely match the theoretical value and remain stable, it always moves up and down near the theoretical value and causes chattering, so the theoretical value is given a certain width and this width is used as a dead band area. It is conceivable to prevent the roll gap adjustment mechanism from operating when the change does not exceed a predetermined value.

It can be seen that by doing this, although complete agreement with the theoretical value cannot be obtained, stable operation within the dead zone region can be obtained and large roll gap errors can also be prevented.

By the way, although it is possible to prevent the roll gap adjustment mechanism from chattering by providing a certain dead zone area, automatic adjustment is not performed in the dead zone area, so there is an error in the removal rate by the amount of variation set as the dead zone area. However, when the amount of paddy supplied is large, the error rate is small, but when the amount of paddy supplied is small, the fluctuation rate of the dehulling rate becomes relatively large, and the automatic roll gap adjustment function becomes meaningless. be.

[Purpose of invention]

The present invention variably controls the width of the dead zone in the roll gap automatic adjustment device depending on the amount of paddy supplied, thereby adjusting the range of fluctuation relative to the set dehulling rate, and achieving stable dehulling without chattering and large errors. The purpose is to provide an automatic adjustment device that maintains the cell rate.

[Summary of the idea]

The present invention is based on a comparison control unit that compares the magnitude relationship of the load current value of the motor with the theoretical current value determined from the amount of paddy supplied and a predetermined dehulling rate, and operates the roll gap adjustment mechanism using a difference signal from the comparison result. A dead band width control section that provides a width to the current value and provides a dead zone region in which no difference signal is output when the fluctuation of the load current value is within this width, and increases or decreases the width of this dead zone region in accordance with the amount of paddy supplied. It is characterized by having the following.

[Example of idea]

FIG. 1 shows a preferred embodiment of the present invention.
The mechanism of the huller, which is equipped with a paddy supply device, a dehulling roll, or a roll gap adjustment mechanism, has a general structure known from the above-mentioned Japanese Patent Application Laid-Open No. 58-114742, etc., and these mechanisms are controlled. Only the circuit part will be explained.

In the figure, reference numeral 1 denotes a well-known load current value detection section, which outputs a voltage corresponding to the load current value of a motor that rotationally drives a demolition roll (not shown). 2 is a theoretical current value setting section, which includes a variable resistor 3 as a paddy supply amount detection section which outputs a voltage corresponding to the opening degree of the supply valve which is proportional to the amount of paddy supplied; and a variable resistor proportional to the amount of paddy supplied. A characteristic conversion circuit 4 that converts the output voltage from 3 into a general characteristic of the load current value with respect to the amount of paddy supplied, and a variable resistor as a dehulling rate setting section for setting a desired dehulling rate in advance by manual operation. It consists of 5.

The voltage corresponding to the theoretical load current value set by the theoretical current value setting section 3 is outputted to the output terminal 6, and together with the output voltage corresponding to the load current value from the load current value detection section 1, the comparison control section 7 is input.

Here, the output voltage equivalent to the theoretical load current value obtained at the output terminal 6 is the characteristic line A corresponding to, for example, a dehulling rate of 90% in the characteristic graph of paddy supply amount and load current value shown in FIG. Although given as an approximation, this value is determined as an ideal load current value when hulling a predetermined amount of paddy supplied at a predetermined dehulling rate.

The comparison control unit 7 detects a voltage equivalent to the load current value (hereinafter referred to as load current value) from the load current value detection unit 1.
and the voltage equivalent to the theoretical load current value from the theoretical current value setting unit 2 (hereinafter referred to as the theoretical current value). When the load current value approaches the theoretical current value, it outputs a control signal according to the fluctuation state, energizes the drive circuit 8 of the roll gap adjustment motor M, and controls the load current value to approach the theoretical current value. A dead zone width control section 9 is provided which inputs a signal related only to the amount of paddy supplied in the theoretical current value setting section 2 and sets a dead zone width commensurate with the amount of paddy supplied.

In other words, the load current value is VA, and the theoretical current value is
When VB is used, the comparison amplifier circuits 10 and 11 first compare the voltages (VA-
VB) and (VB-VA), and when the voltage difference deviates from the preset dead band width Vα, it performs forward/reverse rotation control that approaches the theoretical current value VB, that is, control that widens or narrows the distance between the rolls. be.

Here, the dead band width Vα is given by the output of the characteristic conversion circuit 4 which is related only to the amount of paddy supplied in the theoretical current value setting unit 2, and with this Vα as a reference value, the comparator 12 and 13 outputs a differential voltage (VA−VB ) and (VB−VA), and (VA−VB)>
When Vα, the load current value exceeds the dead band region and becomes larger than the theoretical current value, and the roll gap is narrowed to the extent that the desired demolition rate cannot be maintained, so a control signal is sent to widen the roll gap to an appropriate value. On the other hand, when (VB-VA)>Vα, a control signal that narrows the roll gap is output.

The dead zone width Vα at this time changes in proportion to the amount of paddy supplied, and as shown by the diagonal lines in Figure 2, it is controlled so that when the supply amount is low, Vα is small and when the supply amount is large, Vα is large. .

As a result, when the amount of paddy supplied is small and the load current is small, the dead band width Vα is reduced, the fluctuation width with respect to the theoretical current value VB is reduced, and large fluctuations in the dehulling rate are suppressed. By maintaining the width Vα, it is possible to prevent the roll gap adjustment mechanism from chattering. Also, when the amount of paddy supplied is large and the load current is large,
Although the dead band width Vα also increases, the theoretical current value VB is also large, so the fluctuation rate does not increase relatively so much, and the fluctuation rate does not become large when viewed from the wall removal rate.

In other words, by controlling the dead band width Vα relative to the theoretical current value VB to keep the predetermined dehulling rate constant regardless of the amount of paddy supplied, in proportion to the amount of paddy supplied, the entire range of fluctuations in the amount of paddy supplied can be controlled. The relative fluctuation rate with respect to the demolition rate can be kept small over the period of time, and the chattering operation of the roll gap adjustment mechanism can be effectively prevented.

As a specific example, if the amount of paddy supplied is 100 kg,
It is the same when the load current value is 20A and the dehulling rate is 85%, and when the dead band width is kept constant at the equivalent of 0.5A when the paddy supply amount is 10 kg, the load current value is 5A, and the dehulling rate is 85%.
Even with a dead band width equivalent to 0.5A, the fluctuation rate of the dehulling rate at 10 kg becomes extremely large, and there is a problem that the dehulling rate deviates greatly from the set dehulling rate of 85%. By changing the width of the dead zone and controlling it so that it is equivalent to 0.1A when the feed rate is 10 kg, for example, it is possible to adjust the roll gap without significantly deviating from the set demolition rate of 85%. .

In the above embodiment, the theoretical current value has a range and is used as a dead band region to be compared with the load current value. First, the variation range (including positive and negative) of the load current value VA with respect to the theoretical current value VB is calculated. seek,
The width of the dead zone where this fluctuation range increases or decreases depending on the amount of paddy supplied.
We have explained the method for determining whether or not Vα has been exceeded.
As a comparison method, the theoretical current value VB itself has a range according to the amount of paddy supplied, for example, the theoretical current value range is set as MAX = (VB + Vα), MIN (VB - Vα), or it is proportional to the amount of paddy supplied. Set a dead band width variable K, MAX=VB(1+K), MIN=
By setting it as VB (1-K), the load current value may be compared with a theoretical current value that has a width in advance.

[Effect of idea]

As described above, the present invention provides a range of theoretical current values suitable for obtaining a predetermined demolition rate, uses this as a dead zone area to perform comparison control with the load current value, and also controls the width of the dead zone area. By controlling the increase/decrease in proportion to the supply amount, unnecessary chattering of the roll gap adjustment mechanism is prevented.
In addition, there is an advantage that the fluctuation range of the dehulling rate can be suppressed to an allowable range commensurate with the amount of paddy supplied, and a well-stable dehulling rate can be maintained in a variable range of the amount of paddy supplied.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram of an automatic roll gap adjustment device according to the present invention, and FIG. 2 is a characteristic diagram of the amount of paddy supplied and the theoretical load current value at a predetermined dehulling rate. 1... Load current value detection section, 2... Theoretical current value setting section, 3... Variable resistor for detecting paddy supply amount, 4...
Characteristic conversion circuit, 5...variable resistor for setting the demolition rate,
7... Comparison control unit, 8... Roll gap adjustment motor drive circuit, 9... Dead band width control unit, M... Roll gap adjustment motor.

Claims (1)

[Scope of utility model registration request] The paddy is dehulled by supplying the paddy between the rolls, and based on a comparison between the theoretical current value determined from the amount of paddy supplied and a predetermined dehulling rate, and the load current value of the electric motor that rotationally drives the rolls. In a hulling machine equipped with an automatic roll gap adjustment device that adjusts the roll gap to maintain the predetermined dehulling rate, the magnitude relationship of the load current value to the theoretical current value is compared, and a difference signal is generated based on the comparison result. The theoretical current value in the comparison control unit that operates the roll gap adjustment mechanism has a width, and a dead zone is provided in which no difference signal is output when the fluctuation of the load current value is within this width. 1. An automatic roll gap adjustment device for a rice hulling machine, characterized by comprising a dead zone width control section that increases and decreases in response to.