JPH0530752U - Crankshaft abnormal displacement detection device - Google Patents

Abstract

(57) [Summary] [Structure] The rotating body 4 of the winding transmission mechanism 3 is attached to the free end of the crankshaft 2. A circumferential surface 4a centered on the crankshaft 2 is provided on the outer circumference of the rotating body 4. A sensor 16 is provided which detects the radial displacement of the circumferential surface 4a in a non-contact manner. Circumferential surface 4 detected by this sensor 16
Comparison means is provided for comparing the displacement of a with a preset displacement. An alarm means is provided for issuing an alarm when the detected displacement of the circumferential surface 4a is larger than the set displacement. [Effect] When an engine accessory or the like is driven by being wound around a crankshaft through a transmission mechanism, abnormal displacement due to torsional vibration or bending load of the crankshaft can be reliably detected and an alarm can be issued.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a crankshaft abnormal displacement detection device capable of issuing an alarm when the engine crankshaft is abnormally displaced due to torsional vibration or bending load.

[0002]

[Prior Art]

 The crankshaft of an engine is largely displaced in the radial direction due to torsional vibration at dangerous rotational speeds. Since excessive stress is applied to the crankshaft when such a large displacement occurs, the one that measures the torsional vibration of the crankshaft and issues an alarm when the torsional vibration exceeds a certain value is conventionally used. (See Japanese Utility Model Publication No. 62-19922).

[0003]

[Problems to be solved by the device]

 In a conventional device that detects excessive stress acting on the crankshaft based on torsional vibration, it is necessary to connect a measuring device to the crankshaft. It could not be used at a practical stage where a winding transmission mechanism was attached to drive loads such as engine accessories. In addition, the displacement of the crankshaft due to the effect of bending load could not be detected.

An object of the present invention is to provide a crankshaft abnormal displacement detection device that can solve the above-mentioned problems of the prior art.

[0005]

[Means for Solving the Problems]

 A feature of the present invention is that a rotating body of a winding transmission mechanism is attached to a free end of a crankshaft, and a circumferential surface around the crankshaft is provided on an outer circumference of the rotating body. A sensor that detects the radial displacement of the surface in a non-contact manner is provided, and a comparison means that compares the displacement of the circumferential surface detected by this sensor with a preset displacement is provided. Is provided with an alarm means for issuing an alarm when the displacement is larger than the set displacement.

[0006]

[Action]

 According to the configuration of the present invention, when the crankshaft is displaced in the radial direction by the action of torsional vibration or bending load, the rotating body of the winding transmission mechanism attached to the crankshaft is also displaced in the radial direction. A radial displacement of the circumferential surface formed on the outer circumference of the rotating body is detected by a sensor, and an alarm is issued when the displacement detected by the sensor becomes larger than a preset displacement. Since the rotating body is attached to the free end of the crankshaft, the amount of radial displacement is greater than when it is attached between both ends of the support, and the radial displacement of the crankshaft due to torsional vibration is a winding transmission mechanism. Since it is amplified by the vibration of the wound body, abnormal displacement of the crankshaft can be reliably detected.

[0007]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

In a diesel engine 1 shown in FIG. 1, a pulley 4 of a belt winding transmission mechanism 3 is attached to a free end of a crankshaft 2. The belt 5 wound around the pulley 4 is wound around a pulley 8 attached to an input shaft 7 of an engine accessory 6 such as a pump. The outer periphery of the pulley 4 attached to the crankshaft 2 is polished to form a circumferential surface 4a with the crankshaft 2 as the center. A commercially available sensor 16 is provided which detects the radial displacement of the circumferential surface 4a in a non-contact manner. The sensor 16 outputs an AC voltage signal having a magnitude corresponding to the radial gap G between the circumferential surface 4a and the sensor 16 to the alarm device 17.

As shown in FIG. 2, the alarm device 17 has a known conversion circuit 9 connected to the sensor 16, and this conversion circuit 9 converts an AC voltage signal from the sensor 16 into a DC voltage signal. Output. The value of the output voltage signal of the conversion circuit 9 can be changed and adjusted by the variable resistor 15. The output voltage signal of the conversion circuit 9 is input to one terminal of the comparator 10. The constant voltage signal output from the constant voltage circuit 11 is input to the other terminal of the comparator 10 via the variable resistor 12. The value of the constant voltage signal is changed and adjusted by the variable resistor 12 according to the allowable radial displacement of the crankshaft 2. The output terminal of the comparator 10 is connected to the base of the transistor 13. The collector of the transistor 13 is connected to the light emitting diode 14, and the emitter is grounded. The output of the constant voltage circuit 11 is used as a power source for the conversion circuit 9, the comparator 10 and the light emitting diode 14, and the constant voltage circuit 11 is connected to a DC 24V battery (not shown).

According to the above configuration, when the crankshaft 2 is displaced in the radial direction by torsional vibration or bending load, the circumferential surface 4a of the pulley 4 is also displaced in the radial direction by this displacement. An AC voltage signal corresponding to the displacement of the circumferential surface 4a is output from the sensor 16 to the conversion circuit 9. The DC voltage signal output from the conversion circuit 9 is compared with the constant voltage signal from the constant voltage circuit 11 by the comparator 10, and if the DC voltage signal corresponding to the displacement is larger than a preset constant value, the comparator 10 Outputs a signal to the transistor 13. As a result, a current flows between the collector and the emitter of the transistor 13, the light emitting diode 14 emits light, and it is detected by the light emission of the light emitting diode 14 that the radial displacement of the crankshaft 2 is larger than a preset displacement. be able to . At this time, since the pulley 4 is attached to the free end of the crankshaft 2, the displacement of the circumferential surface 4a is large as compared with the case where it is attached between both ends of the support, and the displacement is amplified by the vibration of the belt 5. Therefore, the displacement of the crankshaft 2 can be reliably detected.

The present invention is not limited to the above embodiment. For example, although the belt winding transmission mechanism is used as the winding transmission mechanism in the above embodiment, a chain winding transmission mechanism may be used. Further, the outer peripheral surface of the pulley 4 is ground to form the circumferential surface 4a, but it is not always necessary to grind. Although the light emitting diode is used as the alarm means, the alarm may be issued by a buzzer.

[0012]

EFFECTS OF THE INVENTION According to the crankshaft abnormal displacement detection device of the present invention, when driving an engine accessory or the like via a transmission mechanism that is wound around the crankshaft, it is affected by torsional vibration or bending load of the crankshaft. Abnormal displacement can be reliably detected and an alarm can be issued.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a crankshaft abnormal displacement detection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a circuit configuration of a crankshaft abnormal displacement detection device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Engine 2 Crankshaft 3 Belt Winding Transmission Mechanism 4 Pulley 4a Circumferential Surface 10 Comparator 14 Light Emitting Diode 16 Sensor

Claims (1)

[Scope of utility model registration request] 1. A rotary body of a winding transmission mechanism is attached to a free end of a crankshaft, and a circumferential surface centering on the crankshaft is provided on an outer circumference of the rotary body, and a radial displacement of the circumferential surface. Is provided in a non-contact manner, a comparison means for comparing the displacement of the circumferential surface detected by this sensor with a preset displacement is provided, and the detected displacement of the circumferential surface is An abnormal displacement detection device for a crankshaft, characterized in that it is provided with an alarm means for issuing an alarm when it is too large.