JPS6252151B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compressor suitable for vehicle air conditioning, and more particularly to a device for detecting abnormalities in the compressor.

In general, compressors for vehicle air conditioning maintain their own temperature at approximately 60 to 100℃ during steady operation, but the lubricating effect of sliding parts decreases due to lack of refrigerant (recently, compressors for vehicle air conditioning In most cases, lubricating oil is supplied to each sliding part along with the movement of refrigerant.) This may increase the amount of frictional heat generated, or the cooling effect may decrease as low-temperature refrigerant is no longer supplied. If the sliding parts seize up and become unable to rotate, or if liquid compression occurs during startup and the piston breaks and the compressor locks, this creates resistance and puts a load on the drive system, resulting in the power source being damaged. There were accidents that caused damage to equipment and related equipment.

Particularly in the case of compressors for vehicle air conditioning, in recent years it has been designed to drive all of the water pump, alternator, compressor, etc. of the vehicle drive engine with a single belt. When the belt is broken due to the inability to rotate, the engine overheats, resulting in a serious vehicle accident.

The present invention has been made in view of the above-mentioned problems, and is designed to prevent seizure of sliding parts due to abnormal overheating of the compressor due to lack of refrigerant in the refrigeration circuit, etc. It is an object of the present invention to provide a compressor abnormality detection device that can protect the power source and related equipment by preventing the compressor lock from having an adverse effect on the power source and related equipment.

Embodiments of the present invention will be specifically described below based on the drawings. First, a first embodiment shown in FIGS. 1 to 5 will be described. As shown in the figure, a pair of opposed cylinder blocks 1 and 2 have an appropriate number of cylinder bores 6 and 7 extending through their centers and parallel to a drive shaft 5 supported by radial bearings 3 and 4. The cylinder bores 6 and 7 are
A piston 8 is slidably fitted in the drive shaft 5, and a ball 12 is mounted on a swash plate 11 which is obliquely fixed to the drive shaft 5 and received by thrust bearings 9 and 10.
It is moored via a bearing device consisting of a shoe 13 and the like. The end faces of the cylinder blocks 1, 2 are sealed by front and rear housings 16, 17 disposed with valve plates 14, 15 in between, and the housings 16, 17 have suction chambers 18, 19, respectively. and discharge chambers 20, 21 are formed. These suction chambers 18, 19 and discharge chambers 20, 21 are communicated with an external refrigeration circuit, respectively, and the cylinder bore 6, It is connected to 7. Although not shown, the suction ports 22, 23 and the discharge ports 24, 2
5 are each provided with a reed valve.

Next, the abnormality detection device, which is the main part of the present invention, will be explained in detail. A protrusion 26 as a detected part for rotation detection is provided at the rear shaft end of the drive shaft 5 at a position eccentric from the axis, and at least the protrusion 26
is made of a magnetic material (for example, a ferrous metal material) or is coated with a magnetic material film. Note that the shape and number of the protrusions 26 can be set as appropriate. A rotation detector 27 is installed approximately at the center of the rear housing 17 at a position facing the rotation locus of the projection 26. The rotation detector 27 includes a substantially cylindrical main body 28 attached to the rear housing 17 and a holder 29 fitted into the main body 28.
and a cylindrical hole 3 bored in the center of the holder 29.
A rod-shaped magnet 31 is inserted movably in the axial direction into the holder 2, and a holder 2 surrounds the magnet 31.
9, a coil 33 wound around an annular groove 32 on the outer periphery;
The rotation detector 27 includes a spring 34 housed in a cylindrical hole 30 to press and bias the magnet 31 toward the protrusion 26, and the rotation detector 27 is equipped with a temperature sensor that deforms in response to the temperature of the compressor. A dish-shaped bimetal 35 is attached. Thus, the bimetal 35 is fitted and held at the tip of the main body 28 exposed in the suction chamber 19, and
The projection 2 of the magnet 31 is detected by detecting the indoor temperature of the magnet 31 and comes into contact with the tip end surface of the magnet 31.
The relative position to 6 is regulated. That is,
When the indoor temperature of the suction chamber 19 is normal, the bimetal 35 projects toward the protrusion 26 as shown in FIG. 2 and holds the magnet 31 in a position close to the protrusion 26 where rotation can be detected. When the temperature increases, the direction of the magnet 31 is reversed as shown in FIG. 3, thereby moving the magnet 31 to a position away from the protrusion 26 where rotation detection is impossible. Note that the coil 33 is connected to an external control device by a lead wire 36.

This embodiment is configured as described above,
The effect will be explained below. During steady operation of the compressor, the bimetal 35 protrudes toward the drive shaft 5 and the magnet 31 is held in a position close to the protrusion 26, which is the detected part. The magnetic flux density of the coil 3 surrounding the magnet 31 changes as the drive shaft 5 rotates.
3, a current is generated. After amplifying the voltage of the current with an amplifier and observing it with an oscillograph or the like, as shown in FIG. 1
This pulse signal is continuously input to the pulse presence/absence detector for normal operation.

However, if the amount of refrigerant in the refrigeration circuit is insufficient,
When the internal temperature of the machine increases due to high-temperature refrigerant returning to the compressor, and the sliding parts are likely to seize, the bimetal 35 is reversed and the magnet 31 is connected to the spring 34. Since the object to be detected is moved away from the protrusion 26, the rotation of the protrusion 26 weakens the change in magnetic flux density (inversely proportional to the square of the distance).
As a result, the rotation detector 27 generates only a very small pulse signal, and as a result, the pulse presence/absence detector can no longer read the pulse signal and determines that there is no pulse signal and disconnects the power source and compressor. Sends a disconnection signal to the electromagnetic clutch. Therefore, the compressor is stopped and seizure of the sliding parts is prevented. Generally, during steady operation, the internal temperature of the compressor increases as the operating speed of the compressor increases.
The faster the speed of passing (traversing) the magnet 31, the larger the pulse signal becomes. Conversely, the larger the distance between the magnet 31 and the protrusion 26, the smaller the pulse signal becomes. On the other hand, if a type in which the deformation occurs gradually is adopted, the signal expansion due to the increase in the operating speed of the compressor and the signal reduction due to the temperature rise are offset, and the pulse signal is always averaged and stable. As a result, sufficiently accurate pulse detection is possible with a detection capability of constant sensitivity. However, in this case, when the temperature exceeds the set temperature (dangerous temperature), it is necessary to finally move the magnet 31 far enough away from the protrusion 26 so that it no longer generates pulses.

In addition, if liquid compression occurs when the compressor is started, resulting in a piston breakage accident, or if the piston becomes unable to rotate even if it does not lead to an accident, the rotation detector 27 will not output a pulse signal. Therefore, the electromagnetic clutch is disconnected through the pulse presence/absence detector, thereby preventing an adverse effect on the power source and related equipment and protecting them.

Next, a second embodiment of the present invention will be described based on FIGS. 6 and 7. In this embodiment, the object to be detected for rotation detection is the swash plate 11, and the rotation detector 27 constituting the abnormality detection device is attached to the outer shell of the cylinder block 2.
2 with a phase difference of 180 degrees and the same rotation locus
The bimetal 35 detects the temperature inside the swash plate chamber 11a that accommodates the swash plate 11. Therefore, this embodiment also operates in the same manner as the first embodiment in response to an abnormality in the compressor, but in particular, the suction chamber 18,
Since the rate of temperature increase when there is a refrigerant shortage is more significant than in the case of the refrigerant 19, the abnormality detection ability of the bimetal 35 can be used more effectively.

In the above-described embodiment, the presence or absence of a pulse signal from the rotation detector 27 is detected, and a disconnection signal to the clutch is issued based on this detection. However, the determination of the presence or absence of this pulse signal depends on the power source It is also possible to configure the rotation speed to be determined by comparing it with a pulse signal from a separate rotation detector that detects the rotation speed, and further, by that comparison, the rotation speed of the compressor can be determined by the corresponding rotation speed of the power source. It is also possible to detect a further drop and issue a disconnection signal to the clutch before damage to the compressor occurs. Further, the bimetal 35 may be either of a type that reverses due to abnormally high temperature and then returns to reverse as the temperature drops, or a type that does not.

As described in detail above, the present invention provides a system for when the compressor becomes abnormally high in temperature due to a lack of refrigerant or locks up due to liquid compression during startup.
By disengaging the clutch that connects the power source, this prevents the sliding parts of the compressor from seizing up, and protects the compressor itself by preventing any negative effects on the power source and its related equipment. In addition, in the present invention, a bimetal that detects abnormally high temperatures and a rotation detector that detects failure to rotate or abnormally low rotation are rationally combined to detect abnormalities. Since the detection device is constructed, the structure can be simplified by reducing the number of parts and sealing points, compared to the case where each temperature and rotation detection and the control system related to the detection are configured independently. Extremely effective.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of a swash plate compressor with an abnormality detection device according to the first embodiment of the present invention, Fig. 2 is a sectional view showing the abnormality detection device during normal operation, and Fig. 3 is a sectional view showing the abnormality detection device during abnormal high temperature operation. Cross-sectional view showing the abnormality detection device, No. 4
The figure is a graph showing pulses, Figure 5 is an explanatory diagram showing the operating mode of the control device, Figure 6 is a front sectional view of a swash plate compressor showing the second embodiment, and Figure 7 is a side sectional view. . 1, 2...Cylinder block, 5...Drive shaft,
11... Swash plate, 16, 17... Housing, 26
...Protrusion, 27...Rotation detector, 31...Magnet,
33...Coil, 35...Bimetal.

Claims (1)

[Scope of Claims] 1. In a compressor connected to a power source by a clutch, there is a detected object provided in a member that moves periodically within the compressor, and a magnetic flux installed facing the detected object. A rotation detector that emits a pulse signal in response to a change in density; a pulse presence/absence detector that detects the absence of the pulse signal and issues a disconnection signal to the clutch; It consists of a bimetal that deforms in response to abnormally high temperatures, and the bimetal is linked to the magnet in the rotating detecting body so that the deformation displaces the magnet in the rotating detecting body to a non-detectable position separated from the detected body. Features: Compressor abnormality detection device. 2. The abnormality detection device for a compressor according to claim 1, wherein the detected object is a protrusion formed protrudingly from a part of a drive shaft of the compressor. 3. The abnormality detection device for a compressor according to claim 1, wherein the object to be detected is an outer circumferential surface of a swash plate that is obliquely fixed to a drive shaft of a swash plate compressor. 4. The abnormality detection device for a compressor according to claim 1, wherein the bimetal is a modified inverted type.