JP3235559B2 - Motor speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation speed control device for a motor used for controlling the rotation speed of a motor provided in a construction machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art In general, construction machines are equipped with a diesel engine as a prime mover, and a hydraulic pump is driven by the diesel engine. Then, a control lever is provided in the cab, and the control lever is connected to the governor mechanism of the engine with a control cable, a link rod, or the like, and the engine speed is controlled by an operator operating the control lever. I was However, in the control method using the control lever, there is a drawback that a large operation force is required to operate the control lever. Therefore, a configuration in which the governor mechanism is remotely controlled using electric means is practically used. Has been

As the electric means, a governor lever is provided on a governor attached to the engine, and the number of revolutions of the engine is detected by rotating the governor lever.
In order to make the number of revolutions of the engine variable, a configuration is provided that includes a lever driving unit including an electric motor and a position detecting unit that detects an angle of a governor lever. On the other hand, the driver's cab is provided with command means as an input side for setting a target rotation speed, and the target rotation speed is set by operating the command means. Then, when the command signal is output by the command means, the command signal is taken into a controller such as a microcomputer, and the command value from the command means is compared with the position of the governor lever detected by the angle detection means, The electric motor is driven to rotate the governor lever so that the two signals match.

FIG. 10 shows a schematic configuration of a rotation speed control device of a prime mover equipped with this kind of governor mechanism. In the figure,
Reference numeral 1 denotes a diesel engine (hereinafter simply referred to as an engine) as a prime mover. Reference numeral 2 denotes a governor provided on the engine 1. The governor 2 is provided with a governor lever 3, and the rotation of the governor lever 3 rotates the engine 1. The number is controlled. Here, the governor lever 3 is connected to the stopper 4
When the governor lever 3 comes into contact with the stopper 4a, the rotation speed of the engine 1 becomes the minimum rotation speed (idle rotation speed) and comes into contact with the stopper 4b. Then, the rotation speed of the engine 1 becomes the maximum rotation speed (full rotation speed).

The governor lever 3 is normally biased by a biasing force of a spring 5 so as to be at a minimum rotational position. The governor lever 3 is stopped by a forward / reverse rotating electric motor 6 as lever driving means. 4a,
It can be displaced to a predetermined angle state within the rotation range regulated by 4b and held at that position. The governor lever 3 and the drive lever 6a provided on the output shaft of the electric motor 6 are connected by connecting means 7 including a control cable, a link, and the like, and power is transmitted. The angle detecting means for detecting the angle of the governor lever 3 is generally constituted by a potentiometer 8, and an input shaft of the potentiometer 8 is provided with an input lever 8a. Is connected to the middle position of.

Further, reference numeral 9 denotes a command means. The command means 9 sets a target rotation speed of the engine 1 by an operation of an operator or the like. And this command means 9
Is input to the controller 10 as a command value signal. The controller 10 operates the electric motor 6 based on the command value signal from the command means 9 to rotate the governor lever 3 to change the rotation speed of the engine 1 to the target rotation speed. it can.

When the controller 10 receives a command value signal from the command means 9, the current position of the governor lever 3 is detected based on an output signal from the potentiometer 8. If the current position of the governor lever 3 is different from the position of the target rotational speed, the electric motor 6 is operated to move the governor lever 3 by an angle corresponding to the deviation.
Is rotated toward the stopper 4a (in the direction of decreasing the rotation speed) or the stopper 4b (in the direction of increasing the rotation speed). As a result of this operation, when the command value signal from the command means 9 matches the detection signal from the potentiometer 8, the governor lever 3 is stopped at that position so that the actual rotation speed of the engine 1 becomes the target rotation speed. Controlled.

Here, the angular position of the governor lever 3 is not detected directly by the angle of the governor lever 3, but is detected indirectly based on the amount of movement of the connecting means 7 connected to the governor lever 3. Therefore, depending on the connection state of the connection means 7 to the governor lever 3 and the connection position of the input lever 8a and the connection means 7 in the potentiometer 8,
The level of the detection signal output from the potentiometer 8 changes. If the connecting means 7 is formed of a rigid rod, the governor lever 3 is always kept stable.
Is detected, but the electric motor 6 cannot be arranged in the vicinity of the engine 1 provided with the governor 2, there is a certain distance between them, and other members are arranged between them. In many cases, the connection means 7 cannot be extended linearly because of the presence of the connection means. For this,
For example, by using a control cable in which a flexible operation wire is inserted through a close contact coil, the routing is facilitated. If the tension is applied to the flexible operation wire in this manner, the flexible operation wire will eventually elongate, causing a detection error by the potentiometer 8.

Then, the governor lever 3 is actually rotated to contact the stopper 4a and reach the lowest rotational speed state, and the level of the voltage signal output from the potentiometer 8 and the stopper 4b to reach the maximum rotational speed. And the level of the voltage signal output from the potentiometer 8 when the number of states is reached.
For example, Japanese Patent Application Laid-Open No. 4-136431 and Japanese Patent Application Laid-Open No.
No. 136432. In this known configuration, in order to detect that the governor lever 3 has pivoted to the lowest rotational speed position and the highest rotational speed position, the detection switches S ₁ , S are located at positions where the governor lever 3 contacts the stoppers 4a, 4b, respectively. _{There are two} . Note that the stoppers 4a and 4b may have functions as these switches.

By setting the lower limit and the upper limit voltage of the potentiometer 8 at the minimum and maximum rotational positions of the governor lever 3 based on the data actually measured by the potentiometer 8, it is possible to assemble the entire drive mechanism of the governor 2. It is possible to prevent the position detection accuracy of the governor lever 3 from being reduced due to an error. Further, even if the connecting means 7 is made of a member whose total length may change over time, such as a control cable, the upper and lower limit voltages of the potentiometer 8 can be adjusted. As a result,
The rotation range of the governor lever 3 and the detection range of the potentiometer 8 can always be made to coincide with each other, so that there is an advantage that the rotation speed of the engine 1 can be controlled very accurately.

As described above, the detection accuracy of the position of the governor lever 3 can be improved by the potentiometer 8. When the target rotation speed from the command means 9 is set, the command value signal of the target rotation speed is compared with the output signal of the potentiometer 8. That is, the command means 9 is a setting side of the target rotation speed, and this is compared with an output signal from the potentiometer 8 which is a current rotation speed detection side. In other words, a push button type up / down switch is used as the command means 9. The up-down switch is composed of an up-side switch and a down-side switch. Depending on how much the engine speed is increased or decelerated from the current engine speed, the up-down switch or the down-side switch is correspondingly increased. Push it in. Therefore, the signal relating to the command value from the command means 9 is not a signal of the rotation speed itself, but an increase / decrease signal with respect to the current rotation speed, so that the governor lever 3 can be accurately arranged at a position where the target rotation speed is reached. There is no particular problem.

[0012]

By the way, it is possible to directly input a target rotational speed irrespective of the current engine rotational speed, instead of increasing or decelerating from the current rotational speed as the command means. It is preferable for the operation. Moreover, since a potentiometer is used as the governor lever angle detecting means, it is easier to compare the current rotational speed with the target rotational speed by setting the target rotational speed as an input side with an analog signal. More preferred. For this purpose, the command means comprises a rotary or slide operation knob and a potentiometer whose output signal level changes in conjunction with the operation of the operation knob. Since both the number detection sides are output signals from the potentiometer, there are advantages such as a simple circuit configuration and easy comparison.

In the case of using the command means using a potentiometer, a stopper is provided on the operation knob to set the level of the output signal (usually a voltage signal) at the minimum rotation speed and the maximum rotation speed. In order to have a predetermined resolution regarding the number of rotations between them, a certain limited stroke is provided in the rotation direction or the linear direction. Here, if the output voltage from the potentiometer at the stroke end position of the operation knob varies, when the operation knob is commanded to be the minimum rotation speed or the maximum rotation speed, the minimum rotation speed or the rotation speed set on the governor lever is specified. Even if the governor lever is not displaced to the position of the maximum rotational speed and the target rotational speed is commanded during that time, the governor lever will not be located at the position corresponding to the target rotational speed.

Although the upper and lower limits of the potentiometer 8 are adjustable, the lower and upper limits of the potentiometer 8 and the adjusted upper and lower limits of the potentiometer 8 are compared with the command means 9. It is necessary to match the output level at the time of setting the minimum rotation speed and the maximum rotation speed. If the position of the operation knob and the output level of the potentiometer on the command means 9 are invariable, the upper limit value and the lower limit value of the actually measured potentiometer 8 on the detection side are set by the command means 9 on the setting side of the target rotation speed. What is necessary is just to adjust so that it may correspond with a potentiometer. For this purpose, the potentiometer and the operation knob of the command means 9 need to be firmly integrated integrally into the housing, and if this is done, not only can it not be disassembled, but also the overall configuration of the command means 9 becomes large. Therefore, the configuration of the command means is significantly increased,
It cannot be easily attached to a console or the like provided in a limited space, such as a cab of a construction machine, and even if a failure occurs, it cannot be repaired, resulting in poor maintainability. There is such a problem.

The present invention has been made in view of the above points, and an object of the present invention is to control the position of the governor lever even when the output level of a potentiometer constituting command means for commanding a target rotational speed changes. An object of the present invention is to enable correction so as to exactly match the level of an output signal with a detection unit.

Another object of the present invention is to provide a control device in which an operation knob and a potentiometer are assembled, based on a command value given by the operation knob even if there are variations in the lower and upper output levels. To control the governor accurately.

[0017]

In order to achieve the above object, the present invention provides a governor for increasing or decreasing the number of revolutions of a prime mover between a predetermined maximum number of revolutions and a minimum number of revolutions. A governor lever provided on the governor, lever driving means for driving the governor lever, position detecting means for the governor lever, command means for commanding a target rotation speed of the prime mover, a command value signal from the command means and the position detection And a controller for controlling the governor lever to drive the governor lever so as to attain a target rotational speed based on a position detection signal from the motor. Operating means for changing the output level of the operating means, and output of at least one operating stroke end position of the operating means. Signal value adjusting means for adjusting the command value signal based on the level of an output signal obtained from the detection signal, and the command value signal adjusted by the command value adjusting means and the position detecting means. And a governor lever position signal is compared.

Here, as the command value adjusting means, of the operation strokes of the operating means, for example, the other signal level can be estimated based on the output signal level of either the lowest rotation speed side or the highest rotation speed side. It is preferable to adjust the signal levels at the minimum rotation speed command value and the maximum rotation speed command value according to the output signal levels at both end positions. The command value adjusting means has a setting switch. The setting switch measures the lower limit value and the upper limit value of the output level of the potentiometer of the command means, and sets the lower limit value and the upper limit value to the minimum rotation speed command value, respectively. And a configuration in which the maximum rotation speed command value is stored in a nonvolatile memory provided in the controller. In particular, a potentiometer is provided for detecting the angle of the governor lever, the position of the governor lever is detected based on the output signal from the potentiometer, and the level of the detection signal is set by the potentiometer constituting the command means. When the control of the governor lever is performed so as to match the level of the output signal at the target rotational speed position, the command value adjusting means is provided with a lower limit value and an upper limit value of the potentiometer on the command means side. It is preferable to include a correction unit that corrects the signal level of the potentiometer on the side of the position detection unit so that the signal level of the upper limit value and the signal level of the lower limit value match.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. In addition,
Except for the configuration of the command means and the controller, there is substantially no difference from the configuration of the above-described conventional technology, and therefore, other than these configurations, the same reference numerals as those used in the description of the conventional technology are used, and Illustration and explanation are omitted.

In FIGS. 1 to 3, reference numeral 20 denotes a command means. The command means 20 is an operation knob 21 as an operation means which is a command side on which a person who operates the machine, such as an operator, sets a target rotation speed, and converts an operation angle of the operation knob 21 into a voltage signal, and outputs a command value. It comprises a potentiometer 22 that outputs a signal, and a top plate 23 that rotatably supports the operation knob 21. The potentiometer 22 is fixedly mounted in a housing 24 having an open upper end, and a top plate 23 is fixed to the housing 24 by means of a bolt or the like in a state where the operation knob 21 is rotatably connected thereto. It has become. Here, the command means 20 is configured as a rotary type, but may be configured as a slide type that moves linearly.

As a specific configuration of the potentiometer 22, for example, as shown in FIG. 3, the potentiometer 22 includes a resistor 25 formed in an arc shape, a sliding contact piece 26, and a rotating shaft 27. The contact piece 26 is attached to a rotating disk 27 a provided to be connected to the rotating shaft 27. A drive portion 21a extending from the operation knob 21 into the housing 24 is connected to the rotation shaft 27 so as to be able to transmit rotation. A rotation operation is performed on the side opposite to the side where the drive portion 21a is provided. Ridge 21b is provided. Therefore, when the ridge 21b of the operation knob 21 is gripped and rotated by hand, the rotation shaft 27 is driven, and the sliding contact piece 26 slides on the resistor 25 in conjunction with this. Become. As a result, the output voltage changes in accordance with the amount of rotation of the rotation shaft 27, and the change in the output voltage becomes substantially linear with respect to the amount of rotation of the rotation shaft 27.

An indicator 23a indicating the target rotation speed is formed in an arc shape on the top plate 23, and a person who performs an operation based on the position of the ridge 21b of the operation knob 21 with respect to the indicator 23a allows the operator to operate the target rotation speed. Will be able to confirm. Therefore, the rotatable range of the operation knob 21 is limited to the angle indicated by the indicator 23a provided on the top plate 23. Operation knob 2 for this
1 has a stopper (not shown) for restricting its rotation.
Is provided. At both stroke end positions of the turning operation of the operation knob 21, the potentiometer 22
Output a minimum voltage (V _min ) and a maximum voltage (V _max ), and if they are arranged at a position between them, a voltage signal corresponding thereto is output from the potentiometer 22.

Next, FIG. 4 shows a circuit configuration of a rotation speed control mechanism of the engine 1 in the controller 30. The controller 30 includes the position of the governor lever 3, that is, the engine 1
The signal from the potentiometer 8 for detecting the current rotational speed of the engine 1 and the signal from the potentiometer 22 for instructing the target rotational speed of the engine 1 are taken in. The output signals from the two potentiometers 8 and 22 are compared by a comparator 31. If there is a deviation between the two output signals, a drive signal based on the deviation is taken into the servo circuit 32 of the electric motor 6. The electric motor 6 is operated.

Here, when the level of the target speed signal detected by the potentiometer 22 is lower than the level of the current speed signal detected by the potentiometer 8, the drive lever 6a connected to the electric motor 6 is turned in the direction of arrow a. By moving, the governor lever 3 is rotated in the direction of arrow A, that is, in the deceleration direction. Conversely, when the level of the output signal of the potentiometer 22 is higher than that of the potentiometer 8, the electric motor 6 is driven so as to rotate the drive lever 6a in the direction of arrow b. It will rotate in the speed direction.
In both the deceleration direction and the acceleration direction, the output level of the potentiometer 8 is
When the two output levels match, the governor lever 3 is held at that position.

As described above, by comparing the levels of the output signals from both potentiometers 8 and 22,
They have the same configuration. Then, as shown in FIG. 5, when the entire angle range in which the resistor of the potentiometer itself is formed is 0 to で あ れ ば, the output voltage shows a substantially linear change within this angle Θ. However, the actual movable angular range of the potentiometer 8, 22, to limit the angular range of the full angular range out of theta ₁ through? _2. For example, it is assumed that when the output voltage of the potentiometers 8 and 22 changes from 0 V to 5 V, 1 V is set to the minimum rotation speed state and 4 V is set to the maximum rotation speed state. In this case, theta ₁ angular position and theta ₂ of the angular position and the reference position, the angle range θ potentiometer from the angle theta ₁ to the angle theta ₂ 8, 22
Is the actual movable angle range. In the potentiometer 8, the governor lever 3 is limited by the angle at which it contacts the stoppers 4a and 4b.
In 2, the rotation stroke of the operation knob 21 by the stopper is limited. Therefore, as shown in FIG. 6, the restricted rotation stroke ranges of the potentiometers 8 and 22 are set so as to coincide with the actual movable angle range θ.

However, the stroke is limited by the governor lever 3 and the operation knob 21, and the angle range of the potentiometers 8 and 22 is not limited. Therefore, these potentiometers 8, 2
2, the range in which the sliding contact piece moves is limited to the actual movable angle range θ, but their actual output voltage range is indicated by, for example, the movable angle range θ ₁ shown by a dotted line in FIG. and so movable angular range theta _2, there may be somewhat shifted to 0V side or 5V side.

On the potentiometer 8 side, the actual movable angle range of the potentiometer 8 may deviate from the actual movable angle range θ due to an assembling error or aging of the drive force transmission system of the governor lever 3 including the connecting means 7. is there. For example, as shown in FIG.
And it grew only more L ₁ minute. Then, the position of the input shaft 8a of the potentiometer 8 at the lowest rotational speed position is shifted by that amount to the position indicated by the virtual line. As a result,
When the governor lever 3 is in the minimum rotation speed state, the output voltage of the potentiometer 8 shifts to the + side from the actual movable angle range θ, and the movable range of the potentiometer 8 from the minimum rotation speed to the maximum rotation speed is θ. It will be ₂ .

On the other hand, the command means 20 comprises an operation knob 21, a potentiometer 22, and a top plate 23, which are integrally assembled, and the assembly is adjusted to an ideal state. If it is held stably in the state, the actual movable angle range θ is obtained. However, they can be disassembled and the top plate 23
May have a simple structure that is connected to the casing 24 of the potentiometer 22 with bolts or the like, the actual movable angle range may be shifted to the 0V side or the 5V side. In particular, once the command means 20
When disassembling and reassembling, the possibility that the operation knob 21 and the potentiometer 22 are displaced is extremely high. As a result, when the operation knob 21 is disposed at the stroke end position on the lowest rotational speed side, the output voltage is 1 V or less, and the output voltage at the stroke end position on the maximum rotational speed side is 4 V or less. The movable range on the 22 side is the angle θ ₁ .

[0029] From the above, when the displacement of the movable angular range theta ₂ of the movable angular range theta ₁ and the potentiometer 22 of the potentiometer 8 is very large, and specifies the predetermined target rotational speed command means 20, the governor lever 3 It will be displaced to a much higher rotational speed position,
The control cannot be performed so that the rotation speed is instructed by the instruction means 20.

Therefore, these potentiometers 8, 22
The level of the output signal is actually measured, and correction data for providing consistency between them is created, and the consistency between the target rotation speed and the actual rotation speed of the engine 1 based on the position of the governor lever 3 is determined. Let me take. For this purpose, the controller 30 is provided with a nonvolatile memory 33 and a correction value calculation circuit 34 for calculating correction data from measured values. Here, the memory 33 and the correction value calculation circuit 34 can be actually constituted by a microcomputer 35. Then, the correction data is to measure the lower limit voltage and upper limit voltage of the potentiometer 8, 22, a deviation between the voltage value at the position of the angle theta ₁ which the lower limit voltage and upper limit voltage as a reference and the angle theta ₂ position This is done by:

The measurement of the output voltage of the potentiometer 8 for detecting the position of the governor lever 3 is performed as follows. That is, detection switches S ₁ and S ₂ are provided to detect both end positions of the rotatable range of the governor lever 3 regulated by the stoppers 4 a and 4 b. Then, the electric motor 6 is operated to rotate the governor lever 3 in the minimum rotation direction. Then, the governor lever 3 is moved to the stopper 4
Detection switch S ₁ is made to ON displaced to the position of a. Therefore, by the electric motor 6 is stopped at a position where the detection switch S ₁ is the turned ON, the voltage outputted from the potentiometer 8 at this time as an output voltage of at minimum rotation speed A /
The data is read by the microcomputer 33 via the D converter 36. Then, the electric motor 6 rotates the governor lever 3 in the maximum speed direction, the detection switch S ₂ and the ON position
Is stopped, and the potentiometer 8 at that position is stopped.
Is read by the microcomputer 33 as an output voltage at the maximum rotation speed. As a result, the output voltage of the potentiometer 8 at the lowest and highest rotation speed positions of the governor lever 3 is measured. It is detected as a deviation of the angle range.

[0032] Similarly, the lower limit of the operating knob 21 in the instruction unit 20, and attaching a set in each stroke end position of the upper switch S _3, S _4, these setting switch S
_3, it is possible to detect the output voltage of the potentiometer 22 at the end positions of the pivoting stroke of the operating knob 21 by S _4. By reading the output voltages from the potentiometer 22 at these positions as a command value of the minimum rotation speed and a command value of the maximum rotation speed to the microcomputer 33 via the A / D converter 37, the actual movable angle in the reference state is obtained. The deviation of the actual movable angle range of the potentiometer 22 from the range θ is detected. The adjustment of the command value signal by the command means 20 is performed based on the deviation. Therefore, the setting switches S ₃ and S ₄ , the memory 33 and the correction value calculation circuit 34 adjust the command value in the potentiometer 22. Means are configured.

The shift on the command means 20 side is caused by the operation knob 2
1 and the top plate 23 and the potentiometer 22, the displacement may be extremely large depending on the assembled state. Here, the potentiometer 8, 22 is to limit an angular range θ of the actual movable angular range relative to the total angular range 0~Θ from angular position theta ₁ to the angular position theta _2, from the angular position theta ₁ small angular position, that is, the output voltage and near 0V, the angular position theta ₂ larger angular position, that is, the output voltage is set as an area to be used for fault detection near 5V. Therefore, if the movable angle range of the operation knob 21 is assembled so as to include this area, it is necessary to perform reassembly as improper assembly.

In consideration of the above points, a description will be given of a procedure for detecting a shift in the potentiometer 22 by the command means 20 and correcting an error based on the shift with reference to FIGS. First, the voltages at both ends of the rotation stroke of the potentiometer 22 after the command means 20 is assembled are measured based on the procedure of FIG. Next, correction data is created according to the procedure shown in FIG.

After the top plate 23 and the operation knob 21 are assembled on the housing 24 provided with the potentiometer 22 constituting the command means 20, the actual output characteristics of the potentiometer 22 are measured. Here, the command means 2
When 0 is newly assembled or when a failure occurs, the output characteristics are measured each time the device is repaired or the whole or parts are replaced, and the output characteristics are determined by the rotation of the potentiometer 22. This is the output voltage level at the position of the operable stroke end. When the assembling of the command means 20 is completed, the output is measured while the power supply is connected to the potentiometer 22. This measurement can be selected, for example, by operating a switch or the like provided on the console of the cab.

When the measurement is started, first, data relating to the past lower limit value and upper limit value stored in the memory 33 is cleared (step 1). In this state, operation knob 2
1 the switch S ₃ makes ON by rotating in the direction of the stroke end position of the lower side (step 2). As a result, the lower limit voltage is output from the potentiometer 22. Here, since the lower limit voltage of the potentiometer 22 must be within a predetermined range, the range of the lower limit voltage is set in advance, and it is determined whether the lower limit voltage has entered this range (step 3). ). Here, since the fixed voltage range on the lower limit and the upper limit is used for failure diagnosis and the like, the settable range of the settable lower limit voltage and upper limit voltage is, for example, ± 1 V and 4 V.
It will be limited to the range of 0.5V. As a result of this determination, if the measured value is out of the settable range, it is necessary to perform re-assembly. A message to the effect that reassembly should be performed is displayed (step 4), and this operation is stopped. Therefore, after the assembly is completed again, the measurement operation is started again. On the other hand, if the lower limit voltage is within the set range, the lower limit voltage is taken into the memory 33 as lower limit value data (step 5).

When the measurement of the lower limit is completed, the operation knob 2
1 by operating the switch S ₄ for capping is rotated until the stroke end position of the upper side of ON (step 6). It is determined whether or not the voltage level of the potentiometer 22 when the switch is ON can be set as the upper limit voltage (step 7).
The operation shifts to step 4 to stop the operation. Therefore, it is necessary to reassemble the command means 20 and start the measuring operation again. If the upper limit voltage of the potentiometer 22 is within the settable range on the upper limit side, the upper limit voltage data is loaded into the memory 33 (step 8). Then, it is determined whether or not the data of the lower limit and the upper limit of the measured values have been loaded into the memory 33 (step 9). When the loading of the data is completed, the measuring operation is completed. If any data has not been determined, the process returns to step 1 and the measurement operation is performed again.

As described above, the potentiometer 22
The output voltage values at both end positions of the stroke of the turning operation are taken into the memory 33, and these are recorded as the voltage level at the time of outputting the target minimum rotation speed and the voltage level at the time of outputting the target maximum rotation speed of the command means 20. Will be done.

[0039] Here, the memory 33 the reference data consisting of angular range θ from the angular position theta ₁ to the angular position theta ₂ are stored in advance. Then, the lower limit and upper limit voltage levels actually measured by the command means 20 are compared with the respective reference values, and correction data is created based on the differences.

In step 10, it is determined whether any of the lower and upper limit data of the potentiometers 8 and 22 has been changed. If any of the data has been changed, the change is made. The measured data on the lower limit side and the upper limit side on the basis of the correction value calculation circuit 3 together with the reference data.
4 (step 11). Then, the calculation of the difference between the measured value and the reference value is performed (step 12). Based on the calculation result, the absolute value of the difference between the lower limit deviation and the upper limit deviation is determined, and it is determined whether or not this value falls within a predetermined setting range (step 13). If the value is out of the setting range, at least one of the upper limit value and the lower limit value has not been accurately measured. For example, since the measurement value was not a measurement value at the stroke end position of the operation knob 21, A display indicating that the preparation of the correction data is stopped and a re-measurement is requested is performed (step 1).
4). Based on this display, the measurement of the lower and upper limit voltages is repeated.

If the difference between the lower limit deviation and the upper limit deviation is within a predetermined error range, the measured lower and upper limit voltage values are regarded as correct, and the average value of these deviations is determined (step 15). By storing this in the memory 33 as a correction value (step 16), the correction data creation mode ends. Assuming that the reference voltage range described above is θ, if the range θ ₂ consisting of the measured lower and upper voltage values is shifted to the 0 V side, the correction value is +. The correction value is a negative value when the voltage is shifted to the 5V side.

On the other hand, the potentiometer 8 for detecting the position of the governor lever 3 also measures the lower limit voltage and the upper limit voltage to create correction data for correcting the deviation from the reference voltage range θ.
Is performed in substantially the same way as in the case of However, the governor lever 3 sets the lower and upper limit voltages to the stoppers 4a, 4a.
These are the levels at the position where they come into contact with b, and these are detected by the detection switches S ₁ and S ₂ . And
For the potentiometer 8 as well, a correction value is obtained from the deviation from the reference voltage range θ, and this correction value is also stored in the memory 33. As described above, the correction value is obtained based on the actual measurement data of the potentiometers 8 and 22.

As described above, the potentiometers 8, 22
Are obtained by calculating correction data from the actually measured values of the lower and upper limit output voltages by the correction value calculation circuit 34, and these correction data are stored in the memory 33. By correcting the actual output signals from the potentiometers 8 and 22 with these correction values and comparing the two signal levels, the governor lever 3 is instructed by the command means 2.
It can be displaced accurately from 0 to the target rotational speed position.

Now, it is assumed that the engine 1 is rotating at a predetermined rotational speed, and the rotational speed of the engine 1 is changed at this time. The control of the rotation speed is performed by the command means 20.
Can be performed by rotating the operation knob 21 that constitutes. Here, the operation of the command means 20 is
The target rotation speed can be set as desired by adjusting the direction of the ridge 21b of the operation knob 21 to a predetermined position of the indicator 23a displayed on 3. When the target rotation speed is set, the potentiometer 22 outputs a voltage signal having a level corresponding to the target rotation speed. On the other hand, the position of the governor lever 3 is detected by the potentiometer 8, and these two signal levels are compared by the comparator 31. In this case, and the adder 38 and 39 respectively provided on the input side of the comparator 31, the corrected data x ₁ and the potentiometer 22 of the potentiometer 8 side from the microcomputer 35 corrects the data x ₂ and is D / A converter Output to these adders 38, 39 via the adders 40, 41, so that the potentiometers 8,
The correction data x ₁ and x ₂ are added to the output signal from the control signal 22.

After the output voltage signals from the potentiometers 8 and 22 are corrected by the correction values x ₁ and x ₂ , respectively,
As a result of the comparison by the comparator 31, if there is a deviation between these two signals, the electric motor 6 operates to rotate the governor lever 3. As a result, the level of the output signal from the potentiometer 8 changes. Then, the output voltages of both potentiometers 8 and 22 match, and when the operation of the electric motor 6 is stopped at that position, the governor lever 3 is displaced to the target rotational speed position.

As described above, even if the commanding means 20 is assembled somewhat roughly, it is possible to reliably correct the deviation of each of the lower and upper limit voltages by the potentiometer 22 from the reference voltage level. As a result, the configuration of the command means including the operation knob 21 and the potentiometer 22 is reduced in size and simplified, and the assembling and disassembly of the commanding means are possible.

In the above-described embodiment, the reference values are set to the actually measured values of the potentiometers 8 and 22.
It is also possible to make correction so that one of the two is used as a reference and the other lower limit and upper limit are adjusted to the reference side. Further, the potentiometer 8 and the potentiometer 22 are the same, but if a potentiometer having a different movable angle range or a different output voltage is used, a predetermined coefficient may be multiplied accordingly. Further, the upper limit position and the lower limit position of the governor lever 3 are configured to be detected by the detection switches S ₁ and S _2. However, after the governor lever 3 comes into contact with the stopper 4 a or 4 b, a drive signal is further output to the drive motor 6. Since the current value increases, the value of the potentiometer 8 at that time may be detected when the current value increases. Furthermore, the operator may recognize that the upper and lower limits of the operation knob 21 have come into contact with the stopper, and output a set signal.

[0048]

As described above, according to the present invention, the command means is constituted by the potentiometer and the operating means for changing the output level of the potentiometer, and the output signal of at least one of the operating stroke end positions of the operating means is provided. And a command value adjusting means for adjusting a command value signal based on a level of an output signal obtained from the detection signal. The command value signal adjusted by the command value adjusting means and a governor lever from the position detecting means are provided. Since the position signal is compared with the command signal, even if there is a variation in the lower limit and the upper limit output level in the command means in which the operating means and the potentiometer are assembled, based on the command value given by the operating means, This has the effect of enabling the governor to accurately control the number of revolutions of the prime mover.

[Brief description of the drawings]

FIG. 1 is a plan view of a command unit used in an embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is an explanatory diagram of a configuration of a potentiometer.

FIG. 4 is a circuit configuration diagram of a rotation speed control device.

FIG. 5 is a diagram showing the relationship between the angle of the potentiometer and the voltage.

FIG. 6 is an explanatory diagram showing the relationship between the entire angle range of the potentiometer, the actual movable angle range within the entire angle range, and the actual movable angle range of the potentiometer.

FIG. 7 is an explanatory diagram showing a situation where adjustment of a movable angle range of a detection-side potentiometer is required.

FIG. 8 is a flowchart showing a procedure for measuring a lower limit voltage and an upper limit voltage value in a potentiometer on the input side of a target rotational speed.

FIG. 9 is a flowchart illustrating a procedure for creating correction data for each lower-limit and upper-limit actually measured voltage value of the potentiometer.

FIG. 10 is a configuration explanatory diagram of an engine speed control device according to a conventional technique.

[Explanation of symbols]

1 engine 2 governor 3 governor lever 4a, 4b
Stopper 6 Electric motor 7 Connecting means 8, 22 Potentiometer 20 Command means 21 Operation knob 30 Controller 31 Comparator 33 Memory 34 Correction value calculation circuit 35 Microcomputer 38, 39 Adders S _{1 to} S ₄
Detection switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI F02D 45/00 310 F02D 45/00 310T (72) Inventor Hiroshi Shimada 650, Kandamachi, Tsuchiura-shi, Ibaraki Pref. Hitachi Construction Machinery Tsuchiura Plant (56) References JP-A-9-53498 (JP, A) JP-A-7-150987 (JP, A) JP-A-59-122908 (JP, A) JP-A-63-55343 (JP, A) JP-A-3-57846 (JP, A) JP-A-57-176630 (JP, U) JP-A-3-49345 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 11/00 F02D 31/00

Claims (4)

(57) [Claims] 1. A governor for increasing or decreasing the rotation speed of a prime mover between a preset maximum rotation speed and a preset minimum rotation speed,
A governor lever provided on the governor, lever driving means for driving the governor lever, position detecting means for the governor lever, command means for commanding a target rotation speed of the prime mover, a command value signal from the command means and the position A controller for controlling the governor lever to drive the governor lever to the lever drive unit so as to reach the target rotation speed based on the position detection signal from the detection unit. Operating means for changing the output level of the potentiometer, detecting an output signal at an operation stroke end position of at least one of the operating means, and setting the command value signal based on the level of the output signal obtained from the detected signal. Command value adjusting means for adjusting the command value, and the command value adjusted by the command value adjusting means. Signals and speed control system for a prime mover, characterized in that the arrangement for comparing the governor lever position signal from the position detecting means. 2. The level of an output signal at both ends of an operation stroke of the operation means is set as the level of the output signal at the time of the minimum rotation speed and the level of the output signal at the time of the maximum rotation speed, respectively. 2. The apparatus according to claim 1, wherein the command value signal is adjusted. 3. The command value adjusting means has a setting switch. The setting switch measures a lower limit value and an upper limit value of an output level of a potentiometer of the command means,
2. The rotation speed control of a motor according to claim 1, wherein the lower limit value and the upper limit value are stored in a nonvolatile memory provided in the controller as a minimum rotation speed command value and a maximum rotation speed command value, respectively. apparatus. 4. The governor lever position detecting means is constituted by a potentiometer, the position of the governor lever is detected based on an output signal from the potentiometer, and the level of the detection signal is set to a target set by the potentiometer of the command means. The position of the governor lever is controlled so as to match the level of the command value signal of the rotation speed, and the command value adjusting means includes a signal level of a lower limit value and an upper limit value of a potentiometer on the command means side, and 4. The rotation speed control device for a motor according to claim 3, further comprising correction means for correcting the signal levels of the upper limit value and the lower limit value of the potentiometer on the position detecting means side to match.