JP2513237Y2 - Vehicle air conditioner compressor protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a protection device for a compressor for a vehicle air conditioner.

[Prior Art] Fig. 7 shows a cooling cycle system diagram for a car cooler.

Compressor 1 is clutch 2, belt 3, engine side pulley
It is connected to the engine 5 of the vehicle via 50, and when the power of the clutch 2 is turned on, the compressor 1 rotates in proportion to the rotation speed of the engine 5. The gas discharged from the refrigeration compressor 1 enters the condenser 6, passes through the receiver 7 and the expansion valve 8 and enters the evaporator 9, where it evaporates and performs cooling action, and then returns to the refrigeration compressor 1.

 A scroll compressor is shown in FIG. 8 as a compressor.

A pulley 4 for transmitting power from the engine 5 and an armature plate 2 are attached to the front case 13 of the compressor, and the armature plate 2 is connected to the shaft 10.

The shaft 10 transmits the force to the orbiting scroll 11 via the bearing 12, and the orbiting scroll 11 rotates with respect to the fixed scroll 13.
Reference numeral 11 makes a swirling motion to compress the refrigerant.

The refrigerant gas that has entered through the suction pipe 14 is guided into the scroll, compressed by the orbiting motion of the orbiting scroll 11, and discharged as high-temperature, high-pressure gas from the discharge pipe 15 of the limmer housing 16.

FIG. 8 shows an example of a cooling cycle protection device. The thermistor 20 is installed in the discharge pipe 15 to detect the discharge dust temperature,
The signal from the thermistor 20 passes through the signal amplification processing unit 17 and enters the signal determination unit 18. From the signal determination unit 18, the relay 1 for turning the clutch power supply 20 on and off based on the determination result.
A signal to drive 9 is sent.

When an abnormal situation such as abnormal friction occurs in the sliding portion of the compressor 1, the discharge gas temperature rises as shown in FIG.
The signal of the thermistor 20 also changes like the temperature shown in FIG.
Output a signal to drive relay 19 to stop 20
Operate relay 19 to turn off the clutch of the compressor and stop the compressor.

[Problems to be solved by the device]

When abnormal friction occurs in the sliding portion of the compressor 1, the discharge gas temperature gradually rises due to an increase in power due to the abnormal friction, but when the degree of the abnormal friction becomes even greater, seizure occurs in the sliding portion and compression occurs. The machine is locked. At that time, slippage occurs between the armature plate 2 and the pulley 4, or the belt 3 transmitting power to the pulley 4 slips. If this state continues for a long time, the belt 3 is damaged by heat generated between the pulley 4 and the belt 3.

When the compressor reaches the locked state and stops rotating, the discharge gas temperature does not rise and the protective device for detecting the discharge gas temperature does not operate.

As a result, the belt is damaged, and even the auxiliary machine such as a generator driven by the belt stops its function, which has a drawback that the function of the automobile is affected.

[Means for solving the problem]

 The present invention takes the following measures to solve the above problems.

That is, as a protection device for the compressor for the vehicle air conditioner,
In a compressor for a vehicle air conditioner in which power is transmitted from a running engine through an endless belt and an electromagnetic clutch, an ultrasonic detecting element is installed on an outer wall of a compressor housing, and a detection signal from the detecting element is amplified by an amplifying circuit, A detection circuit and a protection circuit which processes through an integration circuit whose integration time is inversely proportional to the engine speed and which turns off the electromagnetic clutch when the output signal is above a predetermined level are provided.

[Action]

In the above means, the ultrasonic detecting element detects ultrasonic waves generated in the clutch or the belt-pulley when the sliding part of the compressor has abnormal friction, or when the sliding part locks the compressor. . The signal is amplified by the amplification circuit, detected by the detection circuit, integrated by the integration circuit for a time inversely proportional to the engine speed, and sent to the protection circuit. When the input in the protection circuit is above a predetermined level, it is output to the electromagnetic clutch and the electromagnetic clutch is turned off.

When the number of revolutions of the engine is high, the frequency of the ultrasonic wave generated is also increased almost in proportion, and the output after detection is also increased.
Therefore, by integrating for a time inversely proportional to the rotation speed, almost the same output can be obtained regardless of the rotation speed of the engine.

In this way, when the sliding part is abnormal or the compressor is locked, the electromagnetic clutch is automatically turned off to ensure safety.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS.

The parts described in the conventional example are denoted by the same reference numerals, and the description thereof will be omitted. The parts relating to the present invention will be mainly described.

In FIG. 1, an ultrasonic detection sensor 40 is installed on the outer wall of the front case 30 of the compressor 1. The ultrasonic detection sensor 40 is connected to the signal processing unit 32 via the lead wire 31.

The signal processing unit 32 includes an amplification unit 3 for amplifying a minute signal.
3. A detection unit 34 for extracting the envelope of the ultrasonic signal, and an integration circuit 35 for integrating the signal output from the detection unit 34 for a time inversely proportional to the engine speed. Further, there is provided a protection circuit (comparing circuit) 36 for judging whether or not the signal output from the integrating circuit is at a certain level or higher and generating a signal based on the result and sending it to the relay 19.

A signal proportional to the engine speed is input to the integrating circuit 35 from the distributor 37 of the engine.

In the above, the ultrasonic wave detected by the ultrasonic sensor 40 during the normal operation is at the level shown in FIG. When this signal passes through the amplification section 33 and the detection section 34 in the signal processing section 32, it becomes a waveform as shown in FIG. 3 and is transmitted to the integration circuit 35.

The integrator circuit 35 receives the engine speed and integrates it for a time inversely proportional to the engine speed (see FIG. 4) and outputs it.

For example, the ultrasonic waveform at 1000 rpm is as shown in FIG. 2, and the output waveform after detection at that time is as shown in FIG. 3, which is integrated and output for the integration time determined by FIG. At 36, when compared with the predetermined judgment level and is larger than the judgment level, the clutch OFF signal is generated. Even if the compressor is operated at the same 1000 rpm, if an abnormality such as seizure occurs in the sliding part of the compressor, or if the compressor becomes locked and the clutch slips, the ultrasonic detection sensor as shown in Fig. 5 The output becomes larger, so that the signal output from the integrating circuit 35 becomes larger than in the normal state, and a signal is generated which is judged by the comparator 36 to turn off the clutch.

Next, when the compressor is normal and the rotation speed is 2000 rpm, the generated ultrasonic waves have a waveform as shown in FIG. In this case, the rotation speed is high, but the integration time is shorter than the characteristic shown in FIG.
A signal having substantially the same magnitude as that at rpm is transmitted to the comparator 36.

Whether or not an abnormality has occurred is determined by whether the magnitude of the input signal in the comparison circuit 36 is larger or smaller than the judgment level. When the integration time is constant, the number of signals within the integration time usually increases as the engine speed increases, so the signal output from the integration circuit 35 may be large even if no abnormality occurs, which may cause malfunction. However, in this signal processing unit, even if the rotation speed increases, the integration time decreases accordingly, so that the signal becomes small and no malfunction occurs.

As described above, safety is ensured and accidents that may deteriorate the function of the vehicle are prevented.

[Effect of the Invention] As described above, according to the present invention, when an abnormal situation occurs such that the compressor is locked, the power of the clutch is automatically turned off and the compressor is stopped. Therefore, it is possible to prevent the functional deterioration of the automobile due to the damage of the compressor.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is an operation explanatory view of the same embodiment, FIG. 3 is an operation explanatory view of the same embodiment, and a fourth embodiment.
FIG. 5 is an operation explanatory view of the same embodiment, FIG. 5 is an operation explanatory view of the same embodiment, FIG. 6 is an operation explanatory view of the same embodiment, FIG. 7 is a cooling system diagram of a conventional example, and FIG. 8 is the same. FIG. 9 is a diagram illustrating the operation of the conventional example, which is a structural system diagram of the conventional example.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryuhei Tanigaki 3-1, Asahicho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Air-conditioning factory (72) Inventor Takashi Tanaka Nishiki, Naka-shi, Aichi Prefecture 3-24 No. 17 Nihon Life Sakaemachi Building 7F Shinmei Design Stock Company In-house (56) References JP 62-178788 (JP, A)

Claims (1)

(57) [Scope of utility model registration request] 1. In a compressor for a vehicle air conditioner in which power is transmitted from a running engine via an endless belt and an electromagnetic clutch, an ultrasonic detecting element is installed on an outer wall of a compressor housing, and detection from the detecting element is performed. A protection circuit is provided, which processes a signal through an amplification circuit, a detection circuit, and an integration circuit whose integration time is inversely proportional to the engine speed, and turns off the electromagnetic clutch when the output signal is at a predetermined level or higher. Protective device for vehicle air-conditioning compressor.