JPS62191213A - Compressor protecting device - Google Patents

Abstract

PURPOSE:To prevent a compressor from overspeeding, by providing a compressor protecting device for shutting off a compressor driving circuit when the engine rotational speed is increased so that the rotational speed of a compressor exceeds an allowable limit or when the difference in rotational speed between the engine and the compressor exceeds a predetermined value. CONSTITUTION:The rotational speed 3 of a compressor 1 and the rotational speed of an engine 2 are delivered to a drive control circuit 10 which compares both values with each other. Further, when the difference between both rotational speeds exceeds a predetermined value, a drive control circuit 18 delivers a stop signal for the compressor 1 through an A/C circuit 5 and a relay 6. Further, when the engine rotational speed 4 exceeds an allowable limit for the compressor 1, a drive control circuit 19 delivers a stop signal for the compressor 1 through the A/C circuit 5 and the relay 6 to stop the compressor 1. With this arrangement it is possible to prevent the compressor 1 from overspeeding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a protection device for a compressor used in a vehicle air conditioner.

[Conventional technology]

As such a device, there is a conventional device shown in FIG. 2, for example.

In the figure, l is a compressor, 2 is an engine, 3 is a rotation speed detection sensor that detects the rotation speed of the compressor l,
4 is a rotation speed detection sensor that detects the rotation speed of the engine 2;
5 is an air conditioner circuit (A/C circuit) that drives the vehicle air conditioner; 6 is a relay as a compressor drive circuit that connects and disconnects the magnetic clutch 7 based on the signal from the A/C circuit 5 to drive the compressor l; 8; detects the difference in rotation speed between the compressor 1 and the engine 2 based on the signals from the rotation speed detection sensors 3 and 4, and turns off the relay contact 9 when the difference becomes larger than a predetermined value. This is a drive control circuit that releases the excitation and pauses the operation of the compressor l.

Note that 20 is a battery. Therefore, according to this device, when a difference in rotational speed between the compressor and the engine that exceeds a permissible limit occurs due to a malfunction of the compressor or the like, its operation can be stopped to protect the compressor.

[Problem that the invention seeks to solve]

By the way, such conventional devices determine whether the compressor is malfunctioning based on the difference between the compressor rotation speed and the engine rotation speed, and when the rotation speed difference becomes large, the operation of the compressor is stopped to protect the compressor. However, since the upper limit rotational speed of the compressor is not considered at all, there is a problem that it is not possible to cope with the increase in the rotational speed of the compressor as engine performance has improved in recent years. In other words, due to improved engine performance, the rotation speed of the compressor has increased to its limit rotation speed (approximately 850 Or, p, m
), and an excessive load is placed on the compressor, with conventional equipment, the compressor continues to operate as long as the difference between the engine speed and the compressor speed does not become large, and there is no protection against overspeed. Not done.

Therefore, an object of the present invention is to prevent the compressor from over-rotating beyond the permissible rotation speed by using a conventional circuit without providing a new control circuit.

[Means for solving problems]

In order to achieve the above-mentioned problems and solve the problems of the prior art, the compressor protection device according to the present invention provides a compressor protection device that protects the compressor when at least one of the engine rotation speed and the compressor rotation speed exceeds a predetermined permissible compressor rotation speed. A second drive control means for cutting off the drive circuit of the compressor 2 is provided.

[Effect]

According to the invention, when the compressor rotational speed exceeds its limit rotational speed, the operation of the compressor is stopped.

〔Example〕

FIG. 1 shows an example of a compressor protection device according to the present invention.

In the figure, ■ is a compressor, 2 is an engine, 3 is a rotation speed detection sensor that detects the rotation speed of the compressor l,
4 is a rotation speed detection sensor that detects the rotation speed of the engine 2;
5 is an air conditioner circuit (A/C circuit) that drives the vehicle air conditioner; 6 is a relay as a compressor drive circuit that connects and disconnects the magnetic clutch 7 based on the signal from the A/C circuit 5 to drive the compressor 1; 10 is a drive control circuit that controls the drive of the compressor 1 via the relay 6, and is composed of, for example, a microprocessor. This drive control circuit 10 detects the difference in the rotation speed between the engine 2 and the compressor l based on the signal from the rotation speed detection sensor 3.4, and when the difference exceeds a predetermined value stored in the internal memory, the A/C Compreh 2s1 via circuit 5 and relay 6
The first drive control circuit 18 stops the operation of the A/ It consists of a second drive control circuit 19 that stops the operation of the compressor 1 via a C circuit 5 and a relay 6.

In addition, 20 is Yatsuteri.

Therefore, with this device, the compressor 1 can be operated not only when the rotational speeds of the engine 2 and the compressor 1 are greatly different due to a malfunction of the compressor 1, but also when the compressor 1 is rotating at a high speed due to the high rotational speed of the engine 2. Nsa 1
The operation of the compressor I can be stopped to protect the compressor l from overspeeding. In order to prevent the compressor l from over-rotating, the rotational speed of the compressor l is directly detected based on the signal from the rotational speed detection sensor 3, and whether the rotational speed of the compressor l exceeds the allowable rotational speed stored in advance in the internal memory is determined. Of course, the operation of the compressor 1 may be controlled depending on the conditions.

〔effect〕

As explained above, the compressor/sleeve protection device according to the present invention cuts off the compressor drive circuit when at least one of the engine speed and the compressor compressor speed exceeds a predetermined allowable compressor speed. Since the drive control means is provided, the operation of the compressor can be stopped when the engine speed increases and the compressor speed exceeds its allowable speed. Therefore, overspeeding of the compressor can be prevented and the load placed on the compressor can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a compressor protection device according to the present invention, and FIG. 2 is a diagram showing an example of a conventional compressor protection device. 1... Compressor 2... Engine 3.4... Rotation speed detection sensor 5... Air conditioner circuit (A/C circuit) 6... Relay 7... Magnetic clutch 8.10... Drive Control circuit 9...Relay contact 18...First drive control circuit 19...Second drive control circuit 20...Battery patent applicant Nissan Motor Co., Ltd. Agent Patent attorney Kodai Uezumi figure

Claims (1)

[Claims] A first detection means for detecting the engine rotation speed, a second detection means for detecting the compressor rotation speed, and a rotation speed difference between the engine and the compressor is detected based on the detection results of both detection means, and the difference is determined to be a predetermined value. In a compressor protection device having a drive control means that shuts off the compressor drive circuit when the value exceeds a predetermined allowable rotation speed of the compressor, A compressor protection device comprising a second drive control means that sometimes interrupts a drive circuit of the compressor.