JPS623708Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device that automatically protects a load detection device such as a scale or a load cell included in a dynamometer from transient excessive loads that occur during acceleration and deceleration.

When operating various types of electric dynamometers, including those with built-in gears, under speed control, if the set speed suddenly changes, the acceleration/deceleration at this time will apply an excessive load to the load detection device compared to the steady state load, so the scale This will significantly shorten the life of the load cell. Moreover, in order to have a long life, it is necessary to use a product with a rating higher than necessary, which is uneconomical. Therefore, during acceleration/deceleration, the swinging frame is restrained (locked) to protect the load detection device from applying excessive load, and after steady operation is achieved, the swinging frame is released to enable highly accurate load measurement. It is thought that this will become possible.

However, in the past, the swing frame was restrained by a manually operated locking mechanism, so even if the speed was set manually, the locking operation was cumbersome, and the manual locking mechanism was not effective during automatic operation intended for unmanned operation. Since it is free, there remain problems with the lifespan and accuracy of the load detection device.

The present invention solves these problems and provides a protection device that automatically locks and frees the swinging frame. Hereinafter, the present invention will be explained along with its embodiments with reference to the drawings.

FIG. 1 is a block configuration diagram showing a protection device according to an embodiment of the present invention. In the figure, 1 is a manual speed setting device of a dynamometer, and 2 is an automatic operation device. A speed setting signal such as a voltage corresponding to the set speed is switched by a manual/automatic selection switch SW. 3 is a speed control system for the dynamometer, which controls the dynamometer to a speed according to an input signal. 4 is a function generator, and 5 is a switching device. The function generator 4 inputs the speed setting signal a and outputs a signal having a time change rate smaller than the time change rate of the speed setting signal a as a function signal b. In this example, the switching device 5 is composed of a switch 5a having two contacts, X and Y, and a short circuit 5b, and the speed control system 3 includes a speed setting signal a and a function generator based on the speed setting signal a. Function signal b sent from 4 is switched by switch 5a and inputted. A speed detection device 6 detects the actual speed of the dynamometer and sends out a speed detection signal c such as a voltage corresponding to the actual speed.
7 is a comparator which inputs the speed setting signal a and the speed detection signal c and compares them to determine whether or not the actual speed matches the set speed within a predetermined range, and provides a signal indicating the comparison result. Send d. Since the dynamometer has a large inertia, when the set speed suddenly changes, the actual speed always changes with a delay due to the inertia. Therefore, the set speed and the actual speed do not change suddenly by the same amount at the same time, and the greater the sudden change in the set speed, the greater the difference between the two, so if the difference exceeds a predetermined range, it means that the set speed has changed suddenly. Lock the swing frame. Conversely, if the difference is within a predetermined range, there is no sudden change in the set speed, and there is no need to lock the swing frame. Reference numeral 8 denotes a locking device, which in this example consists of a solenoid valve 9, a hydraulically operated locking mechanism 10, and a pressure switch 11. The pressure switch 11 is activated when a predetermined pressure is applied to the lock mechanism 10, and sends out a signal e indicating that the lock is completed. Instead of a flexible switch, TLRY or the like may be used to detect lock completion. The solenoid valve 9 opens when the comparison signal d indicates a mismatch between the actual speed and the set speed, and closes when the comparison signal d indicates a match. Further, the lock mechanism 10 in this example is a brake mechanism for frictionally braking an arm 13a protruding from the swing frame 13, and FIGS. 2a and 2b show an example in which a hydraulic disc brake is used. Second
In figures a and b, 10a is a hydraulic disc brake, 14 is a dynamometer, 14a is its rotating shaft, 15
1 is a hydraulic floating bearing, 16 is a load cell, 17 is a pedestal, and 18 is a bed. Note that the lock mechanism is not limited to the hydraulic type.

The switch 5a in the switching device 5 described above is, for example, an electronic switch whose switching operation is controlled by the comparison signal d from the comparator 7 and the lock completion signal e from the pressure switch 11. When the comparison signal d indicates that the actual speed does not match the set speed within a predetermined range, the contact Y is connected, and the lock completion signal e is output.
The contact is switched to contact X and closed.

As described above, if the actual speed of the dynamometer does not match the set speed, the swing frame 13 is automatically locked. Moreover, although it takes some time for the swing frame 13 to lock, the function generator 4 is kept active during this time to prevent sudden changes in the set speed, thereby eliminating sudden changes in the actual speed. Also, once the lock is completed, there will be no problem even if the set speed suddenly changes.
The function generator 4 is bypassed by the short circuit 5b to return to normal speed control, and when the actual speed and set speed match, the lock is automatically released and load measurement becomes possible.

As explained above, according to the present invention, the swing frame of the dynamometer can be automatically locked, the life of the load detection device can be extended, and load measurement can be performed with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram showing an embodiment of the present invention, Fig. 2 a and b show an example of a lock mechanism, and a
is a plan view, and b is a front view. In the drawing, 1 is a manual speed setting device, 2 is an automatic operation device, 3 is a speed control system, 4 is a function generator, 5 is a switching device, 6 is a speed detection device, 7 is a comparator,
8 is a lock device, 9 is a solenoid valve, 10 is a lock mechanism, 11 is a pressure switch, 13 is a swing frame, 13a is an arm, 14 is a dynamometer,
16 is a load cell.

Claims (1)

[Scope of utility model registration request] a function generator connected between the speed setting device of the dynamometer and the speed control system, inputting the speed setting signal and transmitting a signal having a time change rate smaller than the time change rate of the speed setting signal as a function signal; a comparator that compares a speed detection signal indicating the actual speed of the dynamometer with the speed setting signal and sends out a comparison signal indicating whether the actual speed matches the set speed within a predetermined range; and a comparison of this comparator. A lock device that locks the swing frame of the dynamometer when the actual speed does not match the set speed based on the signal, releases the lock when the actual speed matches the set speed, detects lock completion, and sends a lock completion signal. and a switching device that bypasses the function generator from the time the lock is completed until the actual speed does not match the set speed based on the comparison signal from the comparator and the lock completion signal from the lock device. Protection device for dynamometer load detection device.