JPH0443795Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a torque measuring device for an electric dynamometer that measures the power of various engines, pumps, etc., and particularly to an automatic calibration circuit thereof.

B. Summary of the invention This invention uses a calibration weight in a torque measuring device for an electric dynamometer that applies the rotating force of the magnetic frame of the electric dynamometer body to a load cell, converts the strain change into an electric signal, and amplifies it to measure torque. A hydraulic cylinder is used as a means to apply the calibration weight, and a limit switch is installed at the calibration weight 0% and 100% positions, while a zero and span adjustment circuit and a calibration necessity determination section are installed on the output side of the amplifier. The hydraulic cylinder is actuated by a calibration increase command or a calibration decrease command, and when the limit switch is activated, whether or not calibration is necessary is determined based on the output voltage, and when calibration is necessary, the adjustment circuit is sent for zero adjustment and span adjustment. The control signal is applied to automatically perform calibration.

C. Prior Art There is a torque measuring device for an electric dynamometer that has a structure in which, in addition to a load cell that measures the rotating force of a magnetic frame, the change in strain is converted into an electric signal, amplified, and given an instruction.

Since this type of torque measuring device requires zero adjustment and span adjustment, the adjustment is performed using a calibration waist and an amplifier having zero adjustment and span adjustment functions.

D. Problems to be solved by the invention When adjusting the zero and span, a voltmeter is connected to the output end of the amplifier while a calibration waist is applied.
Since adjustments were made while looking at the indicated values, there were problems such as time consuming and poor accuracy.

E Means and Actions for Solving Problems The present invention is equipped with a load cell that converts the rotating force of the magnetic frame of the electric dynamometer body into an electric signal, and an amplifier that amplifies the output of this load cell, and measures torque. In an electric dynamometer torque measuring device, calibration is performed by a zero and span adjustment circuit provided on the output side of the amplifier, a command section that issues a calibration start command and a calibration increase/decrease command, and a command signal issued from this command section. a hydraulic cylinder that increases or decreases the weight; a detector that detects whether the calibration weight is 0% or 100% based on the position of the movable rod of the hydraulic cylinder; The present invention is characterized by comprising a calibration necessity determination unit that determines whether or not calibration is necessary based on the output signal of the span adjustment circuit, and supplies a control signal to the zero and span adjustment circuit when calibration is necessary. . F. Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figures 1 and 2 show an embodiment of the present invention, in which 1 is an electric dynamometer body, 2 is a magnetic frame of this body 1, to which rotational force is applied and the change in strain is converted into an electric signal. 3 is an amplifier that increases or decreases the output of the load cell 2; 4 is a zero and span adjustment circuit provided on the output side of the amplifier 3; 5 receives the output voltage and determines whether or not calibration is necessary; 6 is a hydraulic cylinder as a means for applying a calibration weight, and as shown in FIG. Detectors such as limit switches 7 and 8 are provided at the 100% position. Reference numeral 9 is a calibration start switch, and 10 and 11 are command generating units that generate instructions for increasing and decreasing the calibration amount. It should be noted that the calibration necessity determining section 5 makes a determination when the limit switches 7 and 8 are operated.

Next, the operation will be described. First, when the calibration start switch 9 is turned on, it is confirmed that the calibration weight is zero by the ON state of the limit switch 7, and at this point, the calibration necessity determining section 5 determines whether or not calibration is necessary. As a result, when calibration is required, a control signal for zero adjustment is sent to the zero and span adjustment circuit 4, and the adjustment circuit operates so that the output becomes zero. Next, a calibration increase command is issued from the calibration increase command generation unit 10 to operate the hydraulic cylinder 6 and increase the calibration weight. At this time, when the movable rod of the hydraulic cylinder 6 moves to the 100% position, the limit switch 8 operates and the calibration weight reaches 100%.
is confirmed. At this point, the calibration necessity determining section 5 determines whether calibration is necessary or not based on the output voltage. When calibration is required, the output voltage is zero, and a control signal for span adjustment is supplied to the span adjustment circuit 4, and the output voltage is adjusted to 100%.

After this, when a calibration weight reduction command is issued, the calibration weight is decreased until the limit switch 7 at the calibration weight 0% position is turned on, and the limit switch 7 is turned on.
Calibration ends when is turned on.

G. Effects of the invention As described above, according to the invention, a hydraulic cylinder is used as a means for applying the calibration weight, limit switches are provided at the 0% and 100% calibration weight positions, and zero and span adjustments are made on the output side of the amplifier. A circuit and a calibration necessity determining section are installed to determine whether calibration is necessary at the time of limit switch operation, and when necessary, provide control signals for zero adjustment and span adjustment to the adjustment circuit, making the torque measuring device This makes it possible to automatically calibrate the dynamometer, making it easier to handle the dynamometer and improving the accuracy of the measurement circuit.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the torque measuring device for an electric dynamometer according to the present invention, and Fig. 2 is an explanatory diagram of the arrangement of a hydraulic cylinder and a limit switch as means for applying a calibration weight in the same embodiment. be. 1...Dynamometer body, 2...Load cell. 3...
Amplifier, 4...Zero, span adjustment answer, 5...Calibration necessity determination section, 9...Hydraulic cylinder, 7, 8...
... Limit switch, 9... Calibration start switch,
10... Calibration increase command generation unit, 11... Calibration decrease command generation unit.

Claims (1)

[Claims for Utility Model Registration] A torque measuring device for an electric dynamometer that measures torque, comprising a load cell that converts the rotating force of the magnetic frame of the electric dynamometer body into an electrical signal, and an amplifier that amplifies the output of the load cell. , a zero and span adjustment circuit provided on the output side of the amplifier, a command section that issues a calibration start command and a calibration increase/decrease command, and a hydraulic cylinder that increases or decreases the calibration weight according to the command signal issued from the command section. , a detector that detects whether the calibration weight is 0% or 100% based on the position of the movable rod of this hydraulic cylinder; A torque measuring device for an electric dynamometer, comprising: a calibration necessity determining section that determines whether or not calibration is necessary based on the calibration, and supplies a control signal to the zero and span adjustment circuit when calibration is necessary. .