JPH0424662B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a compressor that operates by receiving driving force from an external source, and when the rotation speed of the compressor decreases or stops due to seizure etc. during operation, this condition can be corrected by The present invention relates to a rotational speed detection device that is applied to a protection device that extracts and judges a signal proportional to the rotational speed and cuts off driving force to a compressor.

When the compressor is connected to a power source, if the rotational speed decreases or becomes unable to rotate due to an accident such as seizure of sliding parts, this will act as resistance and put a load on the drive system, resulting in It may damage the power source and related equipment. Particularly in the case of a compressor for a vehicle air conditioner, it is conceivable to configure the crankshaft rotation to drive all of the water pump, alternator, compressor, etc. with a single belt. If the belt is cut due to malfunction, the water pump, alternator, etc. will also be stopped, causing problems such as inducing overheating of the engine.

In order to solve this problem, the rotational speed of the compressor is detected, and based on this detection, if the rotational speed of the compressor decreases or stops, a system is installed between the compressor and the power source. A protection system has been devised in which the clutch acts as a shutoff. Conventionally known electromagnetic induction type detectors are advantageous for detecting the rotational speed of the compressor, and according to this type of detector, pulse signals can be extracted by changing the magnetic flux density using the magnetic material in the rotating part of the compressor. Therefore, this pulse signal can be amplified by an amplifier and a determination device can determine whether or not the rotation of the compressor is normal.

However, when such an electromagnetic induction type detector is used, a problem arises as to which part of the rotating part of the compressor should be used as the magnetic material. In other words, in order to change the magnetic flux density of the electromagnetic induction detector, the magnetic material must pass through the magnetic field, and in order for this to be detected as the rotational speed, at least one part of the compressor must pass through the magnetic field. 1 per rotation
It requires a change in magnetic flux density of times. Conventionally, measures such as forming a recess on the end face of the drive shaft at a position eccentric from the shaft center have been adopted, but doing so requires special machining of the drive shaft.
It was time-consuming. In addition, the detector is attached to the housing or casing of the compressor body, but if this attachment point is in a high-pressure atmosphere, there will be drawbacks such as the sealing structure of the detector itself becoming complicated. .

The present invention has been made based on these circumstances, and is characterized in that the magnetic body on the rotating side of the electromagnetic induction type detector uses a holding member of a shaft sealing device that is originally provided in the compressor. By utilizing such a holding member, special parts and processing can be omitted, and since this type of shaft seal device is installed in the suction chamber, that is, the low pressure side, it is possible to omit special parts and processing. The present invention aims to provide a rotational speed detection device for a compressor in which the seal structure is simplified by installing a detector, and the temperature of the suction chamber is low, so thermal effects are reduced.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

The drawing shows a vane type compressor, and 1 is a cylindrical casing. Both ends of the casing 1 are closed by casing side plates 2 and 3,
A pump chamber 4 is defined in a space surrounded by the casing 1 and the side plates 2 and 3. A rotor 5 is housed in the pump chamber 4 at a position eccentric from the center, and vanes 6 . The rotor 5 is rotatably supported by the casing side plates 2 and 3 via bearings 7 and 7, respectively.

A front housing 8 is attached to one casing side plate 2, and a rear housing 9 is attached to the other casing side plate 3. Front housing 8 and casing side plate 2
A suction chamber 10 is formed between the rear housing 9 and the casing side plate 3, and a discharge chamber 11 is formed between the rear housing 9 and the casing side plate 3. The suction chamber 10 communicates with the pump chamber 4 through a suction port 12, and the discharge chamber 11 communicates with the pump chamber 4 through a discharge port 13 and a check valve (not shown). For example, the refrigerant introduced into the suction chamber 10 from the evaporator of the refrigeration cycle passes through the suction port 12 into the pump chamber 4.
After being pressurized as the volume decreases due to the rotation of the rotor 5, it is sucked into the discharge chamber 1 from the discharge port 13.
The liquid is discharged to 1, and then pumped to the condenser side.

One end of the rotor 5 is integrally or integrally connected to a drive shaft 15, which passes through the suction chamber 10 and is led out of the front housing 8. The distal end of the drive shaft 15 is connected to, for example, a crankshaft of an automobile engine through an electromagnetic clutch 42 shown in FIG. 5 and a belt transmission (not shown).

A shaft sealing device 16 is provided between the drive shaft 15 and the front housing 8. The shaft sealing device 16 is shown in FIGS. 2-4. i.e. 1
A fixing ring 7 is made of a metal with excellent wear resistance, such as iron, and is fixed to the front housing 8 via an O-ring 18. This fixed ring 1
7 and the O-ring 18 prevent leakage of refrigerant flowing from the suction chamber 10 to the outside through the wall surface of the front housing 8. 19 is a material with excellent sliding properties,
For example, it is a sliding ring made of carbon, and is in sliding contact with one end surface of the fixed ring 17. Reference numeral 20 denotes an elastic ring made of rubber, which is elastically attached to the outer circumferential surface of the drive shaft 15 to prevent the refrigerant in the suction chamber 10 from leaking to the outside through the outer circumferential surface of the drive shaft 15. 21 is a holding member, and the drive shaft 1
5 and is rotated together with the drive shaft 15.
The holding member 21 is made of iron-based magnetic material,
It extends in the axial direction and has a plurality of arm parts 22 along the circumferential direction. The arm portion 22... has a locking portion 23... at the tip thereof, and the locking portion 23...
is engaged with a stopper 24 formed on the outer peripheral surface of the sliding ring 19.

A coil spring 25 is attached to the elastic ring 20, and this coil spring 25 is attached to the presser plates 26, 27.
The elastic ring 20 is expanded in the axial direction via. Therefore, the end of the elastic ring 20 is pressed against the sliding ring 19 by the pressing force of the coil spring 25, and the sliding ring 19 is pressed against the end surface of the fixed ring 17 by this pressing force. Therefore, the sliding ring 19 prevents the refrigerant from leaking between the fixed ring 17 and the elastic ring 20. At this time, the holding member 21 is attached to the elastic ring 20, the sliding ring 19, and the coil spring 2.
5 integrally and has a guide function to keep the sliding ring 19 always in contact with the fixed ring 17.

Opposed to the shaft sealing device 16 configured as described above,
An electromagnetic induction detector 30 is installed in the front housing 8.
is installed. Electromagnetic induction detector 30
has a permanent magnet 32 inside the main body 31 made of non-magnetic material.
and a coil 33 surrounding this magnet. This detector 30 is fitted with an O-ring 3 in a mounting hole 34 drilled in the front housing 8.
5 and is fixed with a nut 36. In this case, the tip end surface of the permanent magnet 32 is positioned in the outer radial direction of the holding member 21 so as to face the arm portion 22 of the holding member 21 in the shaft sealing device 16 . A lead wire 37 connected to the coil 33 is connected to an external control device.

As shown in FIG. 5, the control device includes a pulse amplifier 40 and a pulse determiner 41, and the pulse determiner 41 determines the voltage to be applied to the electromagnetic clutch 42 when the voltage is below a set value. The clutch 42 is disconnected.

In the embodiment with such a configuration, the holding member 2 of the shaft sealing device 16 rotates as the drive shaft 15 rotates.
1 rotates integrally, the arm portions 22 of the holding member 21 are connected to the magnets 32 of the detector 30.
pass through a magnetic field. That is, per rotation of the drive shaft 15, the magnetic flux density is changed in proportion to the number of arm parts 22... The change in magnetic flux density is caused by the coil 33
Since an induced current is generated in the lead wire 37, a pulse voltage can be taken out to the lead wire 37. This pulse voltage is amplified by an amplifier 40 and input to a determiner 41. The determiner 41 compares the applied pulse voltage with a set value and sends a signal to the electromagnetic clutch 42 if the applied pulse voltage is less than the set value.
Give a command to shut off 2. That is, when the rotational speed of the compressor falls below a predetermined value, the power from the crankshaft as a power source is cut off, so the compressor can be stopped and the relationship between the crankshaft and the clutch 42 is reduced. The water pump, which is simultaneously driven by the belt, does not place an unreasonable load on the belt interposed between the belts.
This allows the alternator to continue operating.

According to the embodiment described above, the arm portion 22 of the holding member 21 of the shaft sealing device 16 is used as the magnetic material for generating the pulse voltage in the electromagnetic induction detector 30, so a special rotating magnetic material is used. does not require. That is, the holding member 21 is a component originally used as the shaft sealing device 16, and therefore, since the holding member 21 is also used as the rotating magnetic body of the detector 30, an increase in the number of parts is not caused.
Moreover, it does not require any special processing.

Further, since the shaft sealing device 16 is installed inside the suction chamber 10, the detector 30 can also be installed facing the suction chamber 10. Since this suction chamber 10 is on the low pressure side of the entire compressor, the detector 3
A simple sealing structure such as an O-ring 35 can be used without requiring a particularly troublesome high-pressure sealing structure. Furthermore, since the temperature of the refrigerant in the suction chamber 10 is low, there is no adverse thermal effect on the detector 30, resulting in a long life.

Furthermore, since the detector 30 has a mounting hole 34 formed in the front housing 8 and is mounted with a nut 36, the processing of the mounting hole 34 is easy.
Moreover, the work of attaching and detaching the detector 30 can be easily performed from the outside.

In the above embodiment, the arm portion 22 of the holding member 21 serves as the magnetic material for the detector 30.
..., but if the holding member 21 is configured in a cylindrical shape, for example, as shown in FIG. 6 or FIG.
It is also possible to implement by means such as forming 0...

Furthermore, the present invention is not limited to vane type compressors, but can be applied to other compressors such as swash plate type compressors.

As detailed above, the present invention uses the holding member of the shaft sealing device as the magnetic material for the electromagnetic induction detector, so it does not require the use of special parts or troublesome mechanical processing. Manufacturing becomes easier. Furthermore, since the shaft sealing device is installed in the low-pressure part of the compressor, the sealing structure of the detector is simple even if the detector is mounted so as to face the holding member. The structure can also be simplified.

[Brief explanation of drawings]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a sectional view of a vane compressor, FIG. 2 is an enlarged sectional view of its shaft sealing device, and FIG. 3 is a sliding ring. and a side view showing the assembled state of the holding member, FIG. 4 is a view along the arrow line in FIG. 3, FIG. 5 is a diagram for explaining the operation of the control device, and FIGS. 6 and 7 are FIG. 7 is a cross-sectional view showing a modified example of each holding member. 1... Casing, 2, 3... Casing side plate, 4... Pump chamber, 5... Rotor, 6... Vane, 10... Suction chamber, 15... Drive shaft, 16...
Shaft sealing device, 17... Fixed ring, 19... Sliding ring, 20... Elastic ring, 21... Holding member,
22... Arm part, 30... Electromagnetic induction type detector,
60...concave stripe, 70...convex stripe.

Claims (1)

[Claims] 1. A suction chamber formed in a housing, a pump chamber formed in this housing and connected to the suction chamber, and a pump chamber that penetrates the housing and projects from the suction chamber to the outside to receive external power. a drive shaft that receives and rotates; a rotor that is driven by the drive shaft and rotates within the pump chamber to change the volume of the pump chamber to compress and discharge the fluid sucked from the suction chamber; and the drive shaft and the housing. A shaft sealing device is provided to prevent the fluid in the suction chamber from leaking from between the shaft sealing device and the shaft sealing device, which is provided facing the suction chamber, and which holds the shaft sealing member and the shaft sealing member and connects the rotating shaft with the shaft sealing device. In a compressor configured with a holding member that rotates integrally, the holding member of the shaft sealing device is formed of a magnetic material, and the holding member is formed with unevenness or an arm portion along the circumferential direction, and this A rotational speed detection device for a compressor, characterized in that an electromagnetic induction type detector facing the holding member and emitting a pulse signal in response to rotation of the holding member is attached to the housing facing the suction chamber.