JPS625659Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for detecting the rotational speed of a compressor.

If seizure occurs in the sliding parts of the compressor, the load on the drive system increases, leading to accidents such as damage to the V-belt of the drive system. Therefore, the compressor is equipped with a rotational speed detection device, and when the rotational speed of the compressor detected by this rotational speed detection device becomes less than a certain speed ratio compared to that of the drive source, a safety device disconnects the electromagnetic clutch of the drive system. has already been proposed. Conventionally, as the above-mentioned rotational speed detection device, for example, Japanese Patent Application Laid-Open No. 56-167887 or Japanese Utility Model Application No. 56-167
As shown in Japanese Patent No. 175589, it is known that a diametrical groove is formed at the rear end of the drive shaft to serve as a detected portion, and an electromagnetic pickup is provided facing the detected portion.

However, in the case of such a structure, since one diametrical groove is formed at the rear end of the drive part as the detected part, the number of detection signals per one rotation of the drive shaft is small, and it is inevitable that an abnormality will occur. The disadvantage was that the response speed was slow.

Therefore, the purpose of this invention is to provide a rotational speed detection device with excellent responsiveness in abnormal situations. In a compressor having an electromagnetic clutch disposed around the drive shaft for transmitting rotational force to the drive shaft and a gear pump fixed to the drive shaft and rotated by the rotational force of the drive shaft, the teeth of the gear of the gear pump are detected. The present invention provides a rotational speed detection device for a compressor in which a detection sensor is provided facing the detected portion to detect the rotational speed. Therefore, since the gear of the gear pump fixed to the drive shaft was used as the detection target, a detection signal similar to the number of teeth can be obtained for one rotation of the drive shaft.
The above-mentioned problems can be achieved.

Examples of this invention will be described below with reference to the drawings.

1 to 3, a first embodiment is shown, in which a compressor main body 1 is made of a non-magnetic material such as an aluminum alloy, and has valve plates 3a and 3b sandwiched between cylinder blocks 2a and 2b on both sides. The cylinder heads 4a and 4b are fixedly constructed.

The drive shaft 5 is made of a magnetic material such as iron, and is attached to the compressor main body 1, one cylinder head 4a, valve plates 3a, 3b, and cylinder blocks 2a, 2b.
Although it is inserted through the cylinder head 2b, it does not protrude into the other cylinder head 2b. A swash plate 6 is installed at an angle on the drive shaft 5, and radial bearings 7a, 7b and thrust bearings 8 are provided between the drive shaft 5 and the cylinder blocks 2a, 2b.
It is rotatably supported via a and 8b.

Balls 9a and 9b are located near the periphery of the swash plate 6.
and the piston 11 via the shoes 10a and 10b.
is installed, and this piston 11 is inserted into a plurality of cylinder bores 1 formed in the cylinder blocks 2a and 2b.
When the swash plate 6 swings and rotates with the rotation of the drive shaft 5, it reciprocates within the cylinder bore 12, and the valve plates 3a, 3
b. The compression chamber 13 surrounded by the piston 11 and the cylinder bore 12 is configured to expand or contract.

Further, the compression chamber 13 is connected to the valve plate 3.
A low pressure chamber 14 is formed in the cylinder heads 4a, 4b through the suction hole and suction valve (not shown) or the discharge hole and discharge valve (not shown) provided in the cylinder heads 4a, 3b.
a, 14b or high pressure chambers 15a, 15b. One low pressure chamber 14a and the other low pressure chamber 14b
The high pressure chamber 15a on one side and the high pressure chamber 15b on the other side communicate with each other, and furthermore, the low pressure chamber 14b has an inlet port 16 formed in the cylinder head 4b, and the high pressure chamber 15b has an outlet port (also formed in the cylinder head 4b). (not shown). Therefore, when the compression chamber 13 expands or contracts, the suction valve and the discharge valve alternately open and close, compressing the gas sucked through the suction port 16, the low pressure chambers 14a, 14b, and the suction hole. Discharge hole, high pressure chamber 15a, 15
b and is discharged through the discharge port.

A mechanical seal 17 and a seal sheet 18 are interposed between one cylinder head 4a and the drive shaft 5 to maintain the airtightness of the low pressure chamber 14a and the drive shaft 5 protrudes outside. An electromagnetic clutch 19 is provided around the shaft 5 to transmit rotational force to the drive shaft 5.

The electromagnetic clutch 19 is connected to one cylinder head 4.
A pulley 22 is rotatably provided on a cylindrical fixture 20 fixed to a through a ball bearing 21. A belt (not shown) is placed around the outer periphery of the pulley 22 to transmit rotational force from an engine (not shown). A ring-shaped groove 23 is formed on the cylinder head 4a side of the pulley 22, and an electromagnet 24 fixed to the cylinder head 4a is loosely inserted into the groove 23.

A rotor 26 is fixed near the end of the drive shaft 5 via bolts 25, and a clutch plate 28 is attached to the rotor 26 by an elastic member 27, which is movable only in the axial direction.

When the electromagnet 24 is excited, the clutch plate 28 is attracted to the electromagnet 24 side and comes into close contact with the pulley 22 to transmit rotational force to the drive shaft 5. At this time, leakage magnetic flux from the electromagnet 24 causes the drive shaft to 5 is magnetized. For this reason, the inner gear 31 of the gear pump 29, which will be described below, that engages with the drive shaft 5 also becomes magnetized.

The gear pump 29 is connected to the other cylinder head 4b.
The drive shaft 5 is fixed to the drive shaft 5.
In this embodiment, as shown in FIG. 2, it is constructed of a trochoid pump.

The trochoid pump has an outer gear 30 and an inner gear 31 made of a magnetic material.A shaft 31a of the inner gear 31 is engaged with a drive shaft 5, and oil is stored in a reservoir 45. The compressor 1 sucks in the oil that is present in the compressor, and also pumps the oil to each sliding portion of the drive shaft 5 and the compressor body 1 to lubricate the space between the drive shaft 5 and the compressor body 1.

The rotational speed detection device 32 is connected to the gear pump 29.
The teeth 33 of the gear 31 are used as a detected portion 35, and a detection sensor 36 is provided facing the detected portion 35 to detect changes in magnetic flux density. In this embodiment, the teeth 33 of the inner gear 31 are connected to the detected portion 3.
5, and the detection sensor 36 is constituted by a magnetoresistive element and is located in the groove 3 formed in the cylinder head 4b.
The tooth 33 of the inner gear 31 faces the farthest point from the tooth 33 of the outer gear 30 (point P in FIG. 2). When the drive shaft 5 is rotated, the gear 3 fixed to the drive shaft 5 rotates.
1 is also magnetized, and the magnetic flux density generated by the gear 31 is about 400 Gauss. When the tooth 33 passes through point P, the magnetic flux density changes, and the detection sensor 36 detects the drive shaft 5.
It is designed to generate a pulse signal (positive and negative pulse signals seven times during one rotation of the drive shaft 5) proportional to the number of rotations of the drive shaft 5.

The wiring 36a of this detection sensor 36 is connected to a control circuit of the compressor via an abnormality detection circuit (not shown).

In the above configuration, when the electromagnetic clutch 19 is energized, the drive shaft 5 and each gear 3 of the gear pump 29
0 and 31 rotate, and the drive shaft 5 and gear pump 29 are magnetized.

In the detection sensor 36, since the inner gear 31 rotates together with the drive shaft 5, the teeth 33 of the gear 31, which is the detected part 35, face each other one after another, so that the detection sensor 36 generates a pulse signal proportional to the rotation speed of the drive shaft 5. Obtainable.

In FIG. 4 a second embodiment is shown and the first
Although the mounting structure of the detection sensor 36 is different from that of the first embodiment, the other configurations are the same as those of the first embodiment, so the same reference numerals are used in the drawings and the description thereof will be omitted.

That is, a mounting portion 38 is provided on the cylinder head 4b corresponding to the detected portion 35 of the gear pump 29, and a mounting hole 39 is formed in the mounting portion 38.

A protective case 41 is inserted into the mounting hole 39 via an O-ring 40, and the protective case 41 is held by a holding nut 42 screwed into a threaded portion formed on the outer periphery of the mounting portion 38. A magnetoresistive element as a detection sensor 36 fixed with epoxy resin is disposed inside the protective case 41 and faces the detected portion 35 .

This embodiment also has the same effect as the first embodiment.

Note that in the two embodiments described above, the detection sensor 36 is composed of a magnetoresistive element;
It is not limited to this, and may be configured with a Hall element that detects changes in the magnetic flux density of the detected part in the same way as a magnetoresistive element, or may be configured with a permanent magnet and a coil. It can also be configured with an electromagnetic pickup that detects changes in the magnetic flux density applied to the coil.

As described above, according to this invention, the rotational speed detection device is constructed using the gear teeth of the gear pump as the detection target, so that the same number of detection signals as the number of teeth can be obtained for one rotation of the drive shaft. It has excellent responsiveness.

In addition, since the teeth of the gear pump are used as the detected part, there is no need to process the detected part.
This has the advantage that it can be made inexpensive and can be applied to various compressors in which a gear pump is present by making simple structural changes.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of this invention, and FIG. 1 is a sectional view of a rotating swash plate compressor, and FIG.
3 is a sectional view showing the vicinity of the rotational speed detection device, and FIG. 4 is a sectional view of the vicinity of the rotational speed detection device showing a second embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Compressor body, 5... Drive shaft, 19... Clutch, 29... Gear pump, 30, 31... Gear, 32... Rotational speed detection device, 33... Teeth, 3
5...Detected part, 36...Detection sensor.

Claims (1)

[Claims for Utility Model Registration] 1. A drive shaft is inserted into the compressor main body, and an electromagnetic clutch is provided around the drive shaft for transmitting rotational force to the drive shaft, and an electromagnetic clutch that is fixed to the drive shaft and is connected to the drive shaft. A compressor having a gear pump rotated by rotational force, characterized in that teeth of a gear of the gear pump are used as a detection target part, and a detection sensor is provided facing the detection target part to detect the rotation speed. Compressor rotation speed detection device. 2. The rotational speed detection device for a compressor according to claim 1, wherein the detection sensor is comprised of a magnetoresistive element that detects the magnetic flux density generated by the electromagnet of the electromagnetic clutch. 3. The rotational speed detection device for a compressor according to claim 1, wherein the detection sensor is comprised of a Hall element that detects the magnetic flux density generated by the electromagnet of the electromagnetic clutch. 4.Registration of a utility model characterized in that the detection sensor consists of a permanent magnet and a coil, and is composed of an electromagnetic pickup that extracts voltage changes of current generated in the coil due to changes in magnetic flux density passing through the coil of the permanent magnet. A rotational speed detection device for a compressor according to claim 1.