JPH0218317Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a vane-type rotary compressor, for example, a vane-type rotary compressor that compresses gas such as refrigerant gas used in an air conditioner.

(Prior art) This type of conventional vane type rotary compressor is as follows:
The technology shown in Figure 2 is known (Jitsuganaki
59-84715). Vane type rotary compressor 1 shown in the same figure
shows the refrigerant gas suction part between the electromagnetic clutch and the rotor 2 on the left side (not shown), and the refrigerant gas (including some lubricating liquid) led from the cooling device (not shown) passes through the suction hole 3 and rotates in a vane shape. It is absorbed into the compressor 1. The refrigerant gas sucked through the suction hole 3 is transferred to a front plate 4 that rotatably supports the rotor shaft 2a and a front housing 6 having the suction hole 3.
The suction chamber 7 is formed in an annular shape around the rotor shaft 2a. The refrigerant gas sent to the suction chamber 7 is sent between vanes (not shown) around the rotor 2 in the cam ring 8 through a passage (not shown). An annular groove 2b is formed on the surface of the rotor 2 that makes sliding contact with the front plate 4, and this annular groove 2b communicates with a back pressure flow path (not shown) that applies back pressure to the vane (not shown), and the flow path connects the vane. Introduce lubricating oil that applies back pressure. This lubricating oil receives discharge pressure from the rotation of the rotor 2, and is supplied from the lubricating oil reservoir to the back pressure flow path through a designated orifice, which applies back pressure to the vanes and to the various slides around the rotor 2. Designed to lubricate contact parts and shaft supports. A bearing 5 is interposed between the front plate 4 and the rotor shaft 2a, and a back pressure chamber 9 is defined on the right side in the figure, and this back pressure chamber 9 is connected to the annular groove 2b. They face each other and communicate. An annular cover plate 11 is fitted radially inward of the front housing 6 via an O-ring 14, and abuts against the stepped portion 6a. The cover plate 11 and the rotor shaft 2a can rotate relative to each other. The cover plate 11 covers the front housing 6 and the rotor shaft 2a.
A mechanical seal chamber 12 is also defined on the front plate 4 side, and this mechanical seal chamber 12 communicates with the suction chamber 7. A retainer 13 is fixed to the rotor shaft 2a in the mechanical seal chamber 12 so as to be able to rotate integrally with the rotor shaft 2a.
A plurality of claws 13a extending in the axial direction are formed on the outer circumference of the retainer 13. A mechanical seal 15 is in contact with the side surface of the cover plate 11 on the side of the mechanical seal chamber 12, and a protrusion is formed on the outer periphery of the mechanical seal 15, with which the pawl 13a of the retainer 13 engages and restricts mutual relative rotation. A portion 15a is formed. An O-ring 17 is fitted to the inner circumference of the mechanical seal 15, and the mechanical seal 15 and the retainer 1
A spring 18 is interposed between the mechanical seal 15 and the cover plate 11 to press the mechanical seal 15 against the cover plate 11. An annular shaft seal 19 is interposed between the front plate 4 and the rotor shaft 2a, and this shaft seal 19 blocks off the mechanical seal chamber 12 and the back pressure chamber 9.
In this conventional vane type rotary compressor, the mechanical seal chamber 12 is isolated from the back pressure chamber 9 by the shaft seal 19, and the mechanical seal chamber 12 is communicated with the suction chamber 7, so that the internal pressure of the mechanical seal chamber 12, Preventing the temperature from rising to the same level as the back pressure and high temperature of the back pressure chamber 9,
In turn, the back pressure between the cover plate 11 and the mechanical seal 15 in the mechanical seal chamber 12,
This prevents burnout and associated wear caused by insufficient lubrication due to high temperatures.

(Problem to be solved by the invention) However, in such a conventional vane type rotary compressor, the pressure in the mechanical seal chamber 12 communicating with the suction chamber 7 is approximately 5 kg/cm when the rotor 2 is stationary. ² (balance pressure), 2Kg/cm 2 when rotor 2 is rotating at high speed, and negative pressure (0Kg/cm ² when it is low).
^cm2 or less). That is, the pressure inside the mechanical seal chamber 12 differs by more than 5 kg/cm ² between high and low pressures. The force that presses the mechanical seal 15 against the cover plate 11 is equal to the sum of the spring force of the spring 18 and the force exerted on the mechanical seal 15 by the internal pressure of the mechanical seal chamber 12. Therefore, if the spring force of the spring 18 is set so that a lubricating oil film of an appropriate thickness is formed between the cover plate 11 and the mechanical seal 15 when the rotor 2 is stationary, then when the rotor 2 is rotating at high speed, As the internal pressure of the mechanical seal chamber 12 decreases, the pressing force of the mechanical seal 15 against the cover plate 11 becomes insufficient, and a small gap is created between the cover plate 11 and the mechanical seal 15, which prevents refrigerant gas and lubricating oil from flowing outside. There is a risk of leakage. If the spring force of the spring 18 is set to be large in order to prevent such leakage, then when the rotor 2 is at rest, the internal pressure of the mechanical seal chamber 12 will recover to its original size as described above. , mechanical seal 1 to cover plate 11
The pressing force of 5 becomes too large and the cover plate 1
1 and the mechanical seal 15, which may cause wear during startup. Therefore, the present invention has a back pressure chamber 9 and a mechanical seal chamber 12.
By applying the back pressure in the back pressure chamber 9 to the mechanical seal 15 without communicating with the and to effectively prevent wear during startup due to lack of oil film between the mechanical seals 15.

(Means for Solving the Problems) In order to achieve such an objective, the vane type rotary compressor according to the present invention rotatably supports the rotor shaft and has a vane back between it and a groove formed in the rotor. a front plate forming a back pressure chamber into which pressure is introduced; a front housing having a suction hole and defining a suction chamber together with the front plate; a front housing interposed between the front housing and the rotor shaft; an annular cover plate defining a mechanical seal chamber communicating with the suction chamber together with the rotor shaft;
a mechanical seal provided in the mechanical seal chamber that slides in contact with the cover plate and has an O-ring fitted radially inward to seal the mechanical seal chamber from outside air; a retainer fixed to the rotor shaft; and the mechanical seal. A spring compressed between the mechanical seal chamber and the back pressure chamber is interposed between the mechanical seal chamber and the spring so as to isolate the mechanical seal chamber from the back pressure chamber. A shaft seal that presses the mechanical seal toward the cover plate by pressure and the spring force of the spring.

(Function) In the present invention, a shaft seal is interposed between the mechanical seal and the spring to isolate the mechanical seal chamber and the back pressure chamber, and the shaft seal receives the vane back pressure from the back pressure chamber. The mechanical seal is pressed toward the cover plate by the receiving force and the pressing force of the spring. The vane back pressure applied to the shaft seal utilizes the pressure of the discharge gas discharged by the rotation of the rotor, and applies a predetermined range of pressure to the vane back pressure through an appropriate restriction, and is the opposite of the suction pressure. The discharge pressure rises when the rotor rotates, and since it passes through the throttle, the range of pressure change is small (2 to 3 kg/
^cm2 ).

Therefore, the pressing force of the mechanical seal against the cover plate is prevented from changing due to the influence of suction pressure, and an appropriate pressing force can be obtained at all times.
It is possible to effectively prevent leakage of refrigerant gas when the rotor rotates at high speed and wear of the mechanical seal during startup.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a diagram showing a vane type rotary compressor according to an embodiment of the present invention. Explanation of components common to a conventional vane type rotary compressor will be omitted, and common parts will be given common numbers.

In FIG. 1, a mechanical seal 25 is in contact with the side surface of the cover plate 11 on the mechanical seal chamber 12 side, and an O-ring 27 is fitted into the inner peripheral portion of the mechanical seal 25. A retainer 23 is fixed to the stepped portion 2c of the rotor shaft 2a so as to be able to rotate integrally with the retainer 23.
There is a spring 28 on the mechanical seal 25 side of 3.
One end of the two is in contact. mechanical seal 25
A shaft seal 29 is interposed between the spring 28 and the other end of the spring 28, and the shaft seal 29 is pressed toward the cover plate 11 by the spring force of the spring 28. Further, the shaft seal 29 is interposed between the inner peripheral surface of the boss 4a of the front plate 4 and the outer peripheral surface of the rotor shaft 2a, and the shaft seal 29 blocks the mechanical seal chamber 12 and the back pressure chamber 9. ing.

In this embodiment, the back pressure chamber 9 communicates with a back pressure passage (not shown) as described above, and lubricating oil is introduced from the passage to apply back pressure to the vane, and this lubricating oil is discharged. The lubricating oil is supplied from a pressurized lubricating oil reservoir to the back pressure channel through a predetermined throttle, applies vane back pressure, and lubricates the sliding contact portion of the rotor 2 and the shaft support such as the bearing 5. Therefore, when the rotor 2 is stationary, the back pressure chamber 9 is at the balance pressure of the refrigerant circulation path (approximately 5 kg/cm ² ), and when the rotor 2 is rotating, the vane back pressure (approximately 2 to 3 kg/cm ^{2 )} is higher than the balance pressure. (approximately 7 to 8 kg/cm ² ). On the other hand, since the mechanical seal chamber 12 communicates with the suction chamber 7, when the rotor 2 is stationary, the pressure is the above-mentioned balance pressure, and when the rotor 2 is rotating, the pressure is low (approximately 2 kg/cm ² ), especially when the rotor 2 is rotating at high speeds. Sometimes the suction pressure becomes negative (0 kg/cm ² or less). That is, the vane back pressure in the back pressure chamber 9 increases when the rotor 2 rotates, contrary to the suction pressure applied to the mechanical seal chamber 12, and the width of the change is 2.
It is small at ~3Kg/ ^cm2 .

When the rotor 2 rotates, the shaft seal 29
receives the vane back pressure from the back pressure chamber 9, and presses the mechanical seal 25 by this received force and the pressing force from the spring 28. Now rotor 2
If the rotation speed is high, the pressure in the mechanical seal chamber 12 will decrease due to the decrease in suction pressure, but this suction pressure will not act as a pressing force on the mechanical seal 25, and the vane back pressure will increase ^{by 2} to 3 kg/cm2. Since the mechanical seal 25 is pressed by the mechanical seal 25, a desired pressing force is ensured. Furthermore, even if the back pressure on the shaft seal 29 decreases due to the rotational speed of the rotor 2 becoming low or stopping, the reduction in the pressing force will be at most 2
~3Kg/ ^cm2 , so the desired pressing force is ensured,
An oil film with an appropriate thickness is formed between the cover plate 11 and the mechanical seal 25, ensuring good sealing performance during startup and the like.

In this way, in this embodiment, vane back pressure is applied to the mechanical seal 25 via the shaft seal 29 interposed between the cover plate 11 and the spring 28, and the pressing force of the mechanical seal 25 toward the cover plate 11 is increased. can be kept within a desired range at all times. Therefore, while the suction chamber 7 and the mechanical seal chamber 12 are communicated with each other to effectively cool the area around the mechanical seal 25, leakage of refrigerant gas etc. to the outside when the rotor 2 rotates at high speed, and when the rotor 2 is stationary, can be prevented. It is possible to effectively prevent the cover plate 11 and mechanical seal 25 from being burned.

(Effects of the invention) As explained above, according to the invention, by applying the back pressure of the back pressure chamber to the mechanical seal without communicating the back pressure chamber and the mechanical seal chamber,
It is possible to effectively prevent leakage of refrigerant gas and lubricating oil to the outside when the rotor rotates at high speeds, and to prevent burning of the cover plate and mechanical seal and associated wear when the rotor is stationary.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of a vane type rotary compressor according to an embodiment of the present invention, and FIG. 2 is a partial sectional view of a conventional vane type rotary compressor. 1... Vane type rotary compressor, 2... Rotor,
2a... Rotor shaft, 2b... Annular groove (groove), 3... Suction hole, 4... Front plate,
6...Front housing, 7...Suction chamber, 9...
... Back pressure chamber, 11 ... Cover plate, 12 ... Mechanical seal chamber, 13, 23 ... Retainer,
15, 25... Mechanical seal, 17, 27...
O-ring, 18, 28...Spring, 19, 2
9...Shaft seal.

Claims (1)

[Scope of utility model registration request] A front plate that rotatably supports the rotor shaft and forms a back pressure chamber for introducing vane back pressure between it and a groove formed in the rotor, and a front plate that has a suction hole and defines a suction chamber together with the front plate. a housing; an annular cover plate interposed between the front housing and the rotor shaft and defining a mechanical seal chamber communicating with the suction chamber together with the front housing and the rotor shaft; a mechanical seal that slides on the cover plate and has an O-ring fitted on the inside radius to seal the mechanical seal chamber from outside air; and a spring that is compressed between the mechanical seal and a retainer fixed to the rotor shaft. , is interposed between the mechanical seal and the spring so as to isolate the mechanical seal chamber and the back pressure chamber, and receives the vane back pressure of the back pressure chamber and combines the received pressure with the spring force of the spring. a shaft seal that presses the mechanical seal toward the cover plate side.