WO2013175817A1 - Screw compressor - Google Patents

Abstract

The present invention addresses the problem of providing a screw compressor capable of supplying lubrication fluid in an amount suitable to both an operating chamber for compressing gas and a bearing chamber to which a bearing is attached. A screw compressor (1) is provided with: a compressor main body (10) in which are formed an operating chamber in which a pair of male and female rotors rotate and a bearing chamber provided with a bearing for supporting the rotors; an operating chamber oil-supply pipe (20c) for supplying lubrication oil to the operating chamber; a bearing chamber oil-supply pipe (20d) for supplying lubrication oil to the bearing chamber; an oil cooler (3) for cooling the lubrication oil discharged from the operating chamber; a bypass pipeline for bypassing the oil cooler (3); and a three-way valve (21) for opening and closing the bypass pipeline. The operating-chamber oil supply pipe (20c) supplies the lubrication oil cooled by the oil cooler (3) to the operating chamber, the bearing chamber oil supply pipe (20d) branches from the operating-chamber oil supply pipe (20c) to supply lubrication oil cooled by the oil cooler (3) to the bearing chamber, and a flow-adjustment means (22) is provided to the bearing chamber oil supply pipe (20d) to regulate the flow of lubrication oil.

Description

Screw compressor

The present invention relates to a screw compressor.

In the screw compressor, a lubricating liquid such as lubricating oil is supplied to a bearing chamber in which a bearing that supports a screw rotor is incorporated and a working chamber in which gas is compressed. Among these, the supply amount (oil supply amount) of the liquid to the bearing chamber has a great influence on the reliability of the bearing and the operation efficiency of the screw compressor.
If the amount of oil supplied to the bearing chamber is too large, the power loss in the bearing increases and the operating efficiency of the screw compressor decreases. On the other hand, if the amount of oil supplied to the bearing chamber is too small, the lubrication performance for the bearing is lowered and the reliability of the bearing is lowered. Therefore, in order to increase the reliability of the bearing and reduce the power loss, it is necessary to accurately control the amount of oil supplied to the bearing chamber.

For example, in Patent Document 1, “the oil separated by the oil separator 5 is cooled by an oil cooler 6 and supplied to the compressor 1. This oil is between the rotors of the compressor, between the rotor and the casing, and In addition to lubricating the bearings, it also cools the refrigerant gas during the compression process, adjusting the temperature of oil supplied to the compressor by adjusting the amount of oil that bypasses the oil cooler in the downstream of the oil cooler 6. In addition, a control valve 7 for adjusting the flow rate of oil supplied to the compressor is provided downstream of the three-way control valve 8 ”(paragraph). 0022).

Japanese Patent No. 3990186

As disclosed in Patent Document 1, by providing a control valve for adjusting the flow rate of the lubricating oil on the downstream (downstream) side of the oil cooler, the amount of lubricating oil supplied to the oil-fed screw compressor can be reduced. Can be adjusted.
However, the technique disclosed in Patent Document 1 cannot individually adjust the amount of oil supplied to the bearing chamber. Therefore, if the amount of oil supplied to the working chamber is adjusted according to the discharge temperature of the compressed fluid, the amount of oil supplied to the bearing chamber may not be the optimum amount. That is, the amount of oil supplied to the bearing chamber is not the optimum amount of oil that increases the reliability of the bearing and reduces the power loss.

Therefore, an object of the present invention is to provide a screw compressor capable of supplying a supply amount of lubricating liquid suitable for each of a working chamber for compressing gas and a bearing chamber to which a bearing is attached.

In order to solve the above problems, the present invention provides a compressor body in which a working chamber in which a pair of male and female rotors rotate to compress air and a bearing chamber having a bearing for supporting the rotor are formed, and a lubricating liquid in the working chamber. The screw compressor is provided with a first pipe for supplying liquid, a second pipe for supplying liquid to the bearing chamber, and a cooling means for cooling the liquid discharged from the working chamber. The working chamber is supplied with liquid from the first pipe, and the bearing chamber is supplied with liquid from the second pipe having flow rate adjusting means.

According to the present invention, it is possible to provide a screw compressor capable of supplying a supply amount of lubricating liquid suitable for each of the working chamber for compressing gas and the bearing chamber to which the bearing is attached.

It is sectional drawing which shows the structure of the compressor main body of a screw compressor. It is a figure which shows the oil supply path | route of the lubricating oil of the screw compressor which concerns on Example 1. FIG. It is a figure which shows distribution | circulation of the lubricating oil when the temperature of lubricating oil is low. It is a figure which shows distribution | circulation of the lubricating oil at the time of steady operation. It is a figure which shows distribution | circulation of the lubricating oil when an operation load is high. FIG. 6 is a diagram illustrating an oil supply path for lubricating oil of a screw compressor according to a second embodiment. (A) is sectional drawing which shows the structure of an autonomous three-way valve, (b) is sectional drawing which shows the structure of an autonomous on-off valve. (A) is a figure which shows distribution | circulation of lubricating oil in case the temperature of lubricating oil is low, (b) is a figure which shows distribution | circulation of lubricating oil at the time of steady operation. (A) is a figure which shows distribution | circulation of lubricating oil when an operation load is high, (b) is a figure which shows distribution | circulation of lubricating oil when a screw compressor is drive | operated in the state where the load of the bearing became the maximum. is there.

1 Screw compressor 3 Oil cooler (cooling means)
10 Compressor body 11 Male rotor (screw rotor)
13 Working chamber 14a, 14b Bearing 15a, 15b Bearing chamber 20c Working chamber oil supply pipe (first pipe)
20d Bearing chamber oil supply pipe (second pipe)
21 Three-way valve (open / close means)
22 Flow control valve (flow control means)
50 Autonomous open / close valve (flow control means)
51 Autonomous three-way valve (opening / closing means)
52 Restriction (second flow rate adjusting means)

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
[Example 1]

1 is a cross-sectional view illustrating a configuration of a compressor main body of a screw compressor according to a first embodiment, and FIG. 2 is a diagram illustrating a lubricating oil supply path of the screw compressor according to the first embodiment.
The compressor main body 10 according to the first embodiment is incorporated in the screw compressor 1 as shown in FIG. 2 and is a pair of male and female screw rotors (a male rotor 11 and a female rotor (not shown)) that rotate while meshing with each other. It is a compressor that compresses.
The male rotor 11 is housed in a working chamber 13 formed as a hollow portion of the casing 12 together with a female rotor (not shown), and the rotation shaft of each rotor (the rotation shaft 11a of the male rotor 11 is shown in FIG. 1). It is provided to penetrate the working chamber 13. Bearing chambers 15a and 15b to which bearings 14a and 14b for supporting the rotating shaft 11a at both ends are attached are formed at both ends of the working chamber 13 in the axial direction of the rotating shaft 11a.
Although not shown, the female rotor is configured in the same manner, and its rotating shaft is supported by a bearing (not shown) provided in the bearing chambers 15a and 15b.

The casing 12 is formed with a suction port 16 a that takes in a gas to be compressed (in the first embodiment, air) into the working chamber 13 and a discharge port 16 b through which the compressed air is discharged from the working chamber 13. The compressor body 10 is configured such that the air sucked from the suction port 16a is compressed by the rotation of the male rotor 11 and the female rotor (not shown) and discharged from the discharge port 16b.

The bearing chambers 15a and 15b are supplied with a lubricating liquid (in the first embodiment, the lubricating oil) for lubricating the bearings 14a and 14b.
Therefore, bearing lubricating oil supply ports 17a and 17b are formed in the bearing chambers 15a and 15b, respectively. Furthermore, bearing lubricating oil discharge ports 18a and 18b are formed in the bearing chambers 15a and 15b, respectively, in order to discharge the supplied lubricating oil. The bearing lubricating oil discharge ports 18 a and 18 b are communication passages that connect the bearing chambers 15 a and 15 b and the working chamber 13, and the lubricating oil discharged from the bearing chambers 15 a and 15 b is supplied to the working chamber 13. The lubricating liquid is not limited to lubricating oil, and may be other liquids such as water or liquid refrigerant.

Also, the casing 12 is formed with a working chamber oil supply port 19 for supplying lubricating oil to the working chamber 13. In the screw compressor 1, the working chamber 13 is also lubricated to cool the air compressed in the working chamber 13, lubricate the male rotor 11 and the female rotor (not shown), and seal the gap formed in the working chamber 13. Oil is supplied. In the first embodiment, lubricating oil is supplied to the working chamber 13 from the working chamber oil supply port 19 and the bearing lubricating oil discharge ports 18a and 18b. The lubricating oil supplied to the working chamber 13 is discharged from the discharge port 16b together with the compressed air.

The male rotor 11 has the bearing chamber 15a side as the suction side and the bearing chamber 15b side as the discharge side. The working chamber 13 has a low pressure portion formed on the suction side of the male rotor 11 and a high pressure portion formed on the discharge side.
The bearing lubricating oil discharge ports 18 a and 18 b are configured to communicate the bearing chambers 15 a and 15 b with the low pressure portion of the working chamber 13. The suction port 16 a is formed in the low pressure portion of the working chamber 13, and the discharge port 16 b is formed in the high pressure portion of the working chamber 13. Furthermore, the bearing chamber 15b on the discharge side is provided with a bearing temperature sensor 15c that measures the temperature of the supplied lubricating oil as the temperature of the bearing 14b. The bearing temperature sensor 15c is configured to measure the outer ring temperature of the discharge-side bearing 14b.

As shown in FIG. 2, the compressor main body 10 configured as described above is incorporated into a screw compressor 1 having a lubricating oil supply path.
The discharge port 16b of the compressor body 10 is connected to the oil separator 2 by a discharge pipe 20a. In the oil separator 2, the lubricating oil discharged from the compressor body 10 together with the compressed air is separated from the air. And the oil separator 2 is connected to the upstream of the oil cooler 3 which cools lubricating oil via the 3rd pipe line (cooling piping 20b).
With this configuration, the lubricating oil discharged from the working chamber 13 (see FIG. 1) of the compressor body 10 can be supplied to the oil cooler 3.
The oil cooler 3 is a cooling unit that cools the lubricating oil by exchanging heat with the outside air supplied by the fan 3a. In the oil supply path shown in FIG. 2, the lubricating oil is sent from the oil separator 2 pressurized with the pressure of the air compressed by the compressor body 10 and circulates in the oil supply path. In addition, upstream and downstream of the oil supply path shown in FIG. 2 are upstream of the oil separator 2 that sends out the lubricating oil, and upstream and downstream along the flow of the lubricating oil.
In other words, the compressor body 10, the oil separator 2, the oil cooler 3, and the compressor body 10 are upstream and downstream when the lubricating oil flows.

The downstream side of the oil cooler 3 is connected to the working chamber oil supply port 19 of the compressor body 10 via a first pipe (working chamber oil supply tube 20c). With this configuration, the lubricating oil cooled by the oil cooler 3 can be supplied to the working chamber 13 (see FIG. 1) of the compressor body 10 through the working chamber oil supply pipe 20c.

Further, the second pipe line (bearing chamber oil supply pipe 20d) branches from the working chamber oil supply pipe 20c at the branch point P1. The bearing chamber oil supply pipe 20d branches into a suction side oil supply pipe 20d1 and a discharge side oil supply pipe 20d2, and the suction side oil supply pipe 20d1 is formed in a bearing lubricating oil supply port 17a formed in the bearing chamber 15a on the suction side (see FIG. 1). Connected to. The discharge-side oil supply pipe 20d2 is connected to a bearing lubricant supply port 17b formed in the discharge-side bearing chamber 15b (see FIG. 1). With this configuration, the lubricating oil cooled by the oil cooler 3 can be supplied to the bearing chambers 15a and 15b of the compressor body 10 through the bearing chamber oil supply pipe 20d.

Also, the first bypass pipe 20e branches at a branch point P2 from the cooling pipe 20b connecting the oil separator 2 and the upstream side of the oil cooler 3, and the working chamber connecting the downstream side of the oil cooler 3 and the working chamber oil supply port 19 is connected. The second bypass pipe 20f branches from the oil supply pipe 20c at the branch point P3. The branch point P3 where the second bypass pipe 20f branches from the working chamber oil supply pipe 20c is upstream of the branch point P1 where the bearing chamber oil supply pipe 20d branches (that is, between the branch point P1 and the oil cooler 3). preferable. Further, the third bypass pipe 20g branches at a branch point P4 formed in the bearing chamber oil supply pipe 20d. The branch point P4 is formed between the branch point P1 where the bearing chamber oil supply pipe 20d branches from the working chamber oil supply pipe 20c and the bearing chambers 15a and 15b of the compressor body 10.
The first bypass pipe 20e, the second bypass pipe 20f, and the third bypass pipe 20g are connected to the three-way valve 21.

The three-way valve 21 has three connection ports (first connection port 21a, second connection port 21b, and third connection port 21c) so that the three connection ports can be opened and closed by the operation of a valve body (not shown). Composed.
In the first embodiment, the first bypass pipe 20e is connected to the first connection port 21a of the three-way valve 21, the second bypass pipe 20f is connected to the second connection port 21b, and the third bypass pipe 20g is the third connection port. Connect to 21c. The three-way valve 21 is controlled by the control device 4, for example.
The first connection port 21a, the second connection port 21b, and the third connection port 21c of the three-way valve 21 are opened and closed. Therefore, the three-way valve 21 includes a first bypass pipe 20e connected to the first connection port 21a, a second bypass pipe 20f connected to the second connection port 21b, and a third bypass pipe 20g connected to the third connection port 21c, respectively. Functions as opening / closing means for opening and closing.

Further, the bearing chamber oil supply pipe 20d is provided with a flow rate adjusting means 22 for adjusting the flow rate of the lubricating oil between the branch point P1 with the working chamber oil supply pipe 20c and the branch point P4 with the third bypass pipe 20g. . The flow rate adjusting means 22 of the first embodiment only needs to have a function of regulating the flow rate of the lubricating oil flowing through the bearing chamber oil supply pipe 20d, and may be a flow rate adjusting valve or a simple throttle mechanism.

3 to 5 are diagrams illustrating the flow of the lubricating oil in the first embodiment, where the solid line indicates the path through which the lubricating oil flows, and the broken line indicates the path through which the lubricating oil does not flow. A dotted arrow indicates the flow of the lubricating oil.
In the first embodiment, the control device 4 calculates (estimates) the temperature of the discharge-side bearing 14b (see FIG. 1) based on the detection signal input from the bearing temperature sensor 15c, and based on the calculated temperature of the bearing 14b. The three-way valve 21 is controlled. That is, the three-way valve 21 operates based on the temperature of the discharge-side bearing 14b.
FIG. 3 is a diagram illustrating the distribution of the lubricating oil when the temperature of the lubricating oil (the temperature of the discharge-side bearing 14b) is low, such as immediately after the screw compressor 1 is started.

Immediately after the screw compressor 1 is started, the oil separator 2 is not sufficiently pressurized. Further, the temperature of the lubricating oil is low and the viscosity is high.
Therefore, when the temperature of the bearing 14b calculated based on the detection signal input from the bearing temperature sensor 15c is lower than a predetermined value (startup determination threshold), the control device 4 determines that the screw compressor 1 has just started. Then, the control device 4 opens all of the first connection port 21a, the second connection port 21b, and the third connection port 21c of the three-way valve 21. This state is the first state of the three-way valve 21.
When the three-way valve 21 is set to the first state, the first bypass pipe 20e, the second bypass pipe 20f, and the third bypass pipe 20g communicate with each other.

The oil cooler 3 has a structure in which the flow rate is reduced in order to cool the lubricating oil efficiently, and has a higher resistance to the flow of the lubricating oil than the first bypass pipe 20e and the third bypass pipe 20g. Therefore, when the three-way valve 21 is set to the first state, the lubricating oil delivered from the oil separator 2 flows through the first bypass pipe 20e and bypasses the oil cooler 3.
The lubricating oil flowing through the first bypass pipe 20e is diverted to the second bypass pipe 20f and the third bypass pipe 20g by the three-way valve 21.

The lubricating oil flowing into the second bypass pipe 20f from the three-way valve 21 flows into the working chamber oil supply pipe 20c from the branch point P3, and is supplied to the working chamber 13 (see FIG. 1) from the working chamber oil supply port 19 of the compressor body 10. .
On the other hand, the lubricating oil that has flowed from the three-way valve 21 into the third bypass pipe 20g flows into the bearing chamber oil supply pipe 20d at the branch point P4, and further splits into the suction-side oil supply pipe 20d1 and the discharge-side oil supply pipe 20d2. Then, the lubricating oil is supplied from the suction side oil supply pipe 20d1 to the bearing chamber 15a (see FIG. 1) on the suction side via the bearing lubricating oil supply port 17a, and from the discharge side oil supply pipe 20d2 to the bearing lubricating oil supply port 17b. It is supplied to the bearing chamber 15b (see FIG. 1) on the discharge side.

The lubricating oil supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 is discharged from the discharge port 16b together with the compressed air, and flows through the discharge pipe 20a. It flows into the oil separator 2. In the oil separator 2, the lubricating oil is separated from the compressed air and stored.

As described above, when the temperature of the bearing 14b is lower than the predetermined start determination threshold value, the lubricating oil sent from the oil separator 2 bypasses the oil cooler 3 having a large resistance to circulation and is supplied to the compressor body 10. Therefore, even when the oil separator 2 is not sufficiently pressurized, a sufficient amount of lubrication is provided in the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10. Oil can be supplied.

FIG. 4 is a diagram showing the flow of the lubricating oil during steady operation.
The control device 4 increases the temperature of the bearing 14b calculated based on the detection signal input from the bearing temperature sensor 15c to a predetermined value (steady operation determination threshold value) higher than the activation determination threshold value, and a predetermined value ( When it does not increase until the high load determination threshold value), it is determined that the screw compressor 1 is in a steady operation state. Then, the control device 4 closes all of the first connection port 21a, the second connection port 21b, and the third connection port 21c of the three-way valve 21. This state is the second state of the three-way valve 21.

When the three-way valve 21 is set to the second state, the first bypass pipe 20e, the second bypass pipe 20f, and the third bypass pipe 20g are closed. Therefore, the lubricating oil sent from the oil separator 2 and flowing through the cooling pipe 20b flows into the oil cooler 3 without flowing into the first bypass pipe 20e at the branch point P2. The lubricating oil flowing into the oil cooler 3 is cooled by the outside air supplied by the fan 3a and flows into the working chamber oil supply pipe 20c. Since the second bypass pipe 20f is closed by the three-way valve 21, the lubricating oil flowing through the working chamber oil supply pipe 20c does not flow into the second bypass pipe 20f at the branch point P3, and the working chamber oil supply port of the compressor body 10 is used. 19 is supplied to the working chamber 13 (see FIG. 1).

Further, at the branch point P1, a part of the lubricating oil flowing through the working chamber oil supply pipe 20c flows into the bearing chamber oil supply pipe 20d, and flows through the suction side oil supply pipe 20d1 and the discharge side oil supply pipe 20d2 so as to receive the bearing lubricant oil supply port 17a, 17b is supplied to bearing chambers 15a and 15b (see FIG. 1).

The lubricating oil supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 is discharged from the discharge port 16b together with the compressed air, and flows through the discharge pipe 20a. It flows into the oil separator 2. In the oil separator 2, the lubricating oil is separated from the compressed air and stored.

In the first embodiment, the bearing chamber oil supply pipe 20d is provided with the flow rate adjusting means 22 to appropriately regulate the flow rate of the lubricating oil flowing through the bearing chamber oil supply pipe 20d. Accordingly, the amount of lubricating oil supplied to the bearing chambers 15a and 15b (see FIG. 1) is appropriately regulated, and the power loss in the bearings 14a and 14b (see FIG. 1) can be suppressed. As a result, the fall of the operating efficiency of the screw compressor 1 is suppressed, and effects, such as energy saving, are produced.
The flow rate adjusting means 22 may be configured to regulate the flow rate of the lubricating oil in the bearing chamber oil supply pipe 20d so that the lubricating oil is supplied to the bearings 14a and 14b to such an extent that the power loss can be suppressed.

As described above, when the temperature of the bearing 14 b rises to a predetermined steady operation determination threshold value, the lubricating oil sent from the oil separator 2 is cooled through the oil cooler 3 and supplied to the compressor body 10. At this time, the supply amount of the lubricating oil supplied to the bearing chambers 15a and 15b (see FIG. 1) is regulated by the flow rate adjusting means 22, and power loss in the bearings 14a and 14b (see FIG. 1) can be suppressed.
The working chamber 13 (see FIG. 1) is supplied with cooled lubricating oil. Therefore, the air compressed in the working chamber 13 can be effectively cooled.

FIG. 5 shows a case where the operation load is high, for example, when the discharge pressure of air from the compressor body 10 is high, or when the rotation speed of the male rotor 11 (see FIG. 1) and the female rotor (not shown) is high. It is a figure which shows distribution | circulation of lubricating oil.
When the temperature of the bearing 14b calculated based on the detection signal input from the bearing temperature sensor 15c rises to a predetermined value (high load determination threshold) higher than the steady operation determination threshold, the control device 4 increases the screw compressor 1. It is determined that a load operation state has been reached. And the control apparatus 4 closes the 1st connection port 21a of the three-way valve 21, and opens the 2nd connection port 21b and the 3rd connection port 21c. This state is the third state of the three-way valve 21.

When the three-way valve 21 is set to the third state, the first bypass pipe 20e is closed. Therefore, the lubricating oil sent from the oil separator 2 and flowing through the cooling pipe 20b flows into the oil cooler 3 without flowing into the first bypass pipe 20e at the branch point P2. The lubricating oil flowing into the oil cooler 3 is cooled by the outside air supplied by the fan 3a and flows into the working chamber oil supply pipe 20c.

The second connection port 21b and the third connection port 21c of the three-way valve 21 are opened, and the lubricating oil flowing through the working chamber oil supply pipe 20c is diverted at the branch point P3, and one of the three way valves 21c flows through the working chamber oil supply pipe 20c. Then, it is supplied to the working chamber 13 (see FIG. 1) from the working chamber oil supply port 19 of the compressor body 10.
The lubricating oil that has been branched at the branch point P3 and flows into the second bypass pipe 20f flows into the third bypass pipe 20g via the three-way valve 21, and flows into the bearing chamber oil supply pipe 20d at the branch point P4. The lubricating oil flowing through the bearing chamber oil supply pipe 20d flows through the suction-side oil supply pipe 20d1 and the discharge-side oil supply pipe 20d2 from the bearing lubricating oil supply ports 17a and 17b of the compressor body 10 to the bearing chambers 15a and 15b (FIG. 1). ).

The lubricating oil supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 is discharged from the discharge port 16b together with the compressed air, and flows through the discharge pipe 20a. It flows into the oil separator 2. In the oil separator 2, the lubricating oil is separated from the compressed air and stored.

By passing through the second bypass pipe 20f and the third bypass pipe 20g from the branch point P3, the lubricating oil can bypass the flow rate adjusting means 22, and the lubricating oil is supplied to the bearing chambers 15a and 15b (see FIG. 1). Supply amount can be increased. As a result, a sufficient amount of lubricating oil can be supplied to the bearings 14a and 14b when the operating load increases and the load on the bearings 14a and 14b (see FIG. 1) increases. Therefore, the bearings 14a and 14b having increased loads can be sufficiently lubricated with the lubricating oil, and poor lubrication of the bearings 14a and 14b can be prevented.
The bearings 14 a and 14 b are supplied with cold lubricating oil cooled by the oil cooler 3. Therefore, the bearings 14a and 14b, which have become high temperature under a large load, can be cooled with the lubricating oil.

As described above, the screw compressor 1 according to the first embodiment includes the oil supply path for supplying the lubricating oil to the working chamber 13 (see FIG. 1) that compresses air by the compressor body 10, and the bearing chamber 15 a of the compressor body 10. 15b (see FIG. 1), the oil supply path for supplying the lubricating oil is configured to be an independent path. The oil supply path for supplying the lubricating oil to the bearing chambers 15a and 15b is provided with the flow rate adjusting means 22, and the oil supply path for bypassing the flow rate adjusting means 22 is further provided.
Accordingly, a suitable amount of lubricating oil corresponding to the start-up, steady operation, and high-load operation is supplied to the bearing chambers 15a and 15b without greatly affecting the amount of lubricant supplied to the working chamber 13. Can supply.

Further, the supply amount of the lubricating oil supplied to the bearing chambers 15a and 15b can be suitably regulated by passing the lubricating oil through the flow rate adjusting means 22. Therefore, it is possible to prevent a decrease in operating efficiency due to an increase in power loss.
Further, by bypassing the flow rate adjusting means 22, the supply amount of the lubricating oil supplied to the bearing chambers 15a and 15b can be increased. Therefore, a sufficient amount of lubricating oil can be supplied to the bearings 14a and 14b (see FIG. 1) as necessary, and the lubricating performance for the bearings 14a and 14b can be maintained.
In this manner, the lubrication performance for the bearings 14a and 14b can be maintained while suppressing an increase in power loss, and the reliability for the bearings 14a and 14b can be ensured.

Further, the oil supply path through which the lubricating oil flows through the flow rate adjusting means 22 and the oil supply path through which the lubricating oil bypasses the flow rate adjusting means 22 are switched by the control of the three-way valve 21 by the control device 4.
And the control apparatus 4 was set as the structure which calculates (estimates) the temperature of the bearing 14b (refer FIG. 1) of the discharge side with which the compressor main body 10 is equipped, and controls the three-way valve 21 based on the temperature of the bearing 14b.
With such a configuration, it is possible to supply a suitable supply amount of lubricating oil according to the temperature of the bearing 14b to the bearings 14a and 14b (see FIG. 1).

For example, when the screw compressor 1 is started, a sufficient amount of lubricating oil is supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 without passing through the oil cooler 3. Can supply.
Further, during steady operation of the screw compressor 1, a sufficient supply amount of lubricating oil can be supplied to the working chamber 13, and a supply amount of lubricating oil that can suppress lost power is supplied to the bearing chambers 15a and 15b. Can do.
When the operating load of the screw compressor 1 is high (during high load operation), a sufficient supply amount of lubricating oil cooled by the oil cooler 3 can be supplied to the working chamber 13 and the bearing chambers 15a and 15b. Therefore, a sufficient amount of the cooled lubricating oil is also supplied to the bearings 14a and 14b (see FIG. 1) where the load becomes high, and the bearings 14a and 14b can be cooled.

The installation position of the bearing temperature sensor 15c is preferably on the inner ring side of the bearings 14a and 14b (see FIG. 1). However, the inner ring of the bearings 14a and 14b is a drive unit, and the sensor wiring is complicated. Installation is difficult.
Further, the load on the discharge-side bearing 14b is larger than that on the bearing 14a provided on the suction side. From the above, in the first embodiment, the bearing temperature sensor 15c is configured to detect the temperature of the outer ring of the discharge-side bearing 14b.
[Example 2]

FIG. 6 is a diagram illustrating a lubricating oil supply path of the screw compressor according to the second embodiment, and FIG. 7 is a diagram illustrating a structure of an autonomous three-way valve and an autonomous on-off valve provided in the screw compressor of the second embodiment. .
The configuration of the screw compressor 1a according to the second embodiment is substantially the same as the configuration of the screw compressor 1 (see FIG. 2) according to the first embodiment, and the same components as those of the screw compressor 1 shown in FIG. A detailed description is omitted with reference numerals.

The screw compressor 1a according to the second embodiment includes an autonomous on-off valve 50 instead of the flow rate adjusting means 22 (see FIG. 2) between the branch point P1 and the branch point P4 of the bearing chamber oil supply pipe 20d. The autonomous on-off valve 50 has two connection ports 50a, and the bearing chamber oil supply pipe 20d is connected to the connection ports 50a. The autonomous on-off valve 50 functions as a flow rate adjusting unit that adjusts the flow rate of the lubricating oil flowing through the bearing chamber oil supply pipe 20d in the same manner as the flow rate adjusting unit 22.

Further, an autonomous three-way valve 51 is provided in place of the three-way valve 21 (see FIG. 2) to which the first bypass pipe 20e, the second bypass pipe 20f, and the third bypass pipe 20g are connected. The autonomous three-way valve 51 has three connection ports (first connection port 51a, second connection port 51b, and third connection port 51c), the first bypass pipe 20e is connected to the first connection port 51a, and the second The bypass pipe 20f is connected to the second connection port 51b, and the third bypass pipe 20g is connected to the third connection port 51c.
The third bypass pipe 20g is provided with a throttle 52 between the third connection port 51c of the autonomous three-way valve 51 and the branch point P4. The restrictor 52 functions as a second flow rate adjusting means for adjusting the flow rate of the lubricating oil flowing through the third bypass pipe 20g.

The autonomous open / close valve 50 is configured to operate at the temperature of the lubricating oil, and the lubricating oil flowing through the oil take-out pipe 20h is taken in from the take-in port 502a and discharged from the discharge port 502b to the oil return pipe 20i. The autonomous three-way valve 51 is also configured to operate at the temperature of the lubricating oil, and the lubricating oil flowing through the oil take-out pipe 20h is taken in from the intake 512a and discharged from the discharge 512b to the oil return pipe 20i.
The screw compressor 1a according to the second embodiment may not include the control device 4 (see FIG. 2) and the bearing temperature sensor 15c (see FIG. 2).

As shown in FIG. 7A, the autonomous three-way valve 51 has a substantially cylindrical casing 511, for example. The inside of the housing 511 is divided in the axial direction, and a valve body driving portion 512 is formed on one side and a connection port opening 513 is formed on the other side. In the connection port opening 513, the third connection port 51c, the second connection port 51b, and the first connection port 51a are opened in this order along the axial direction from the valve body driving unit 512 side. The third connection port 51c, the second connection port 51b, and the first connection port 51a communicate with each other through the connection port opening 513.

In addition, a valve body 514 that moves in the axial direction is provided inside the housing 511. The valve body 514 is attached to the connecting port opening 513 side of the rod 514a and the rod 514a penetrating from the connecting port opening 513 to the valve body driving unit 512, and the inside of the connecting port opening 513 is changed according to the displacement of the rod 514a. And an opening / closing portion 514b that moves in the axial direction.

The opening / closing part 514b closes the corresponding connection port when moved to the position of the connection port (the third connection port 51c, the second connection port 51b, the first connection port 51a) that opens to the connection port opening 513. The open / close portion 514b is formed with a communication path 514c that allows connection ports that are not closed to communicate with each other. With this configuration, the opening / closing portion 514b closes one of the connection ports and communicates the two connection ports that are not closed with each other.

The wax 515 is attached to the end of the rod 514a on the valve body drive unit 512 side. The wax 515 is configured to expand and contract in the axial direction of the housing 511 inside the valve body driving unit 512 due to a change in ambient temperature. The inside of the valve body drive unit 512 is filled with oil (valve body drive oil) that drives the valve body 514 by expanding and contracting the wax 515. The wax 515 expands and contracts according to the temperature of the valve body driving oil, and the rod 514a is displaced in the axial direction according to the expansion and contraction of the wax 515.

For example, in the configuration in which the wax 515 expands (extends) as the temperature of the valve body driving oil increases, the rod 514a is displaced toward the connection port opening 513 as the temperature of the valve body driving oil increases, and the opening / closing section 514b. Moves in a direction away from the valve body drive unit 512. The opening / closing part 514b closes the first connection port 51a farthest from the valve body driving part 512. At this time, the third connection port 51c and the second connection port 51b communicate with each other. This state is defined as a first state of the autonomous three-way valve 51.

When the temperature of the valve body drive oil decreases, the wax 515 contracts, the rod 514a is displaced toward the valve body drive unit 512, and the opening / closing unit 514b moves in a direction approaching the valve body drive unit 512. The opening / closing part 514b closes the second connection port 51b at the position of the second connection port 51b that opens between the third connection port 51c and the first connection port 51a. At this time, the third connection port 51c and the first connection port 51a communicate with each other via a communication path 514c formed in the opening / closing part 514b. This state is the second state of the autonomous three-way valve 51.

When the temperature of the valve body drive oil further decreases, the wax 515 further contracts and the rod 514a is further displaced toward the valve body drive unit 512. Then, the opening / closing part 514b moves to the valve body driving part 512 side and closes the third connection port 51c. At this time, the second connection port 51b and the first connection port 51a communicate with each other. This state is the third state of the autonomous three-way valve 51.

As described above, the autonomous three-way valve 51 is switched between the first state, the second state, and the third state according to the temperature of the valve body drive oil filled in the valve body drive unit 512. Then, the first connection port 51a, the second connection port 51b, and the third connection port 51c are opened and closed, respectively. Therefore, the autonomous three-way valve 51 is connected to the first bypass pipe 20e connected to the first connection port 51a, the second bypass pipe 20f connected to the second connection port 51b, and the third connection port 51c. The third bypass pipe 20g functions as an opening / closing means for opening and closing each.

Furthermore, the valve body drive unit 512 is formed with an intake port 512a for taking in the valve body drive oil and a discharge port 512b for discharging the valve body drive oil. With this configuration, the wax 515 expands and contracts in accordance with the temperature of the valve body drive oil taken in from the take-in port 512a, and displaces the rod 514a.

In the second embodiment, the lubricating oil after lubricating the discharge-side bearing 14b (see FIG. 1) of the compressor body 10 is used as the valve body driving oil. Therefore, as shown in FIG. 6, the intake port 512a of the valve body drive unit 512 is provided with a bearing chamber 15b (see FIG. 1) on the discharge side of the compressor body 10 via the oil take-out pipe 20h. It connects with the location through which lubricating oil after lubricating 14b flows. Moreover, the discharge port 512b of the valve body drive part 512 is connected with the discharge piping 20a via the oil return pipe | tube 20i.
According to this structure, the valve body drive part 512 of the autonomous three-way valve 51 is filled with the lubricating oil after the bearing 14b is lubricated. The autonomous three-way valve 51 operates according to the temperature of the bearing 14b, more specifically, the temperature of the lubricating oil after lubricating the bearing 14b, and the first state, the second state, and the third state are switched.

The autonomous open / close valve 50 has a structure substantially equivalent to the autonomous three-way valve 51. As shown in FIG. 7B, the autonomous on-off valve 50 includes a substantially cylindrical casing 501, for example. The inside of the housing 501 is divided in the axial direction, and a valve body driving unit 502 is formed on one side and a connection port opening 503 is formed on the other side. Two connection ports 50 a are opened in the connection port opening 503, and the two connection ports 50 a communicate with each other via the connection port opening 503. Further, the two connection ports 50a are formed, for example, at a substantially central portion in the axial direction in the connection port opening 503.

A valve body 504 that moves in the axial direction is provided inside the housing 501. The valve body 504 is attached to the rod 504a penetrating from the connection port opening 503 to the valve body driving unit 502, and the connection port opening 503 side of the rod 504a, and the inside of the connection port opening 503 is changed according to the displacement of the rod 504a. And an opening / closing portion 504b that moves in the axial direction.
The opening / closing portion 504b closes the two connection ports 50a when moved to the position of the two connection ports 50a that open to the connection port opening 503.

The wax 505 is attached to the end of the rod 504a on the valve body drive unit 502 side. The wax 505 is configured to expand and contract in the axial direction of the housing 501 inside the valve body driving unit 502 due to a change in ambient temperature. The inside of the valve body driving unit 502 is filled with valve body driving oil that drives the valve body 504 by expanding and contracting the wax 505. The wax 505 expands and contracts according to the temperature of the valve body drive oil, and the rod 504a is displaced in the axial direction according to the expansion and contraction of the wax 505.

The wax 505 is configured to expand (elongate) as the temperature of the valve body driving oil increases, similarly to the wax 515 of the autonomous three-way valve 51, and the rod 504a is connected to the connection opening 503 as the temperature of the valve body driving oil increases. The opening / closing part 504b moves in a direction away from the valve body driving part 502.
The opening / closing portion 504b moves to the end side of the connection port opening 503 rather than the two connection ports 50a formed at the substantially central portion in the axial direction in the connection port opening 503 to open the two connection ports 50a. To do. This state is the open state of the autonomous open / close valve 50.

When the temperature of the valve body drive oil decreases, the wax 505 contracts, the rod 504a is displaced toward the valve body drive unit 502, and the opening / closing unit 504b moves in a direction approaching the valve body drive unit 502. The opening / closing part 504b closes the two connection ports 50a at the positions of the two connection ports 50a. This state is a closed state of the autonomous open / close valve 50.

When the temperature of the valve body drive oil further decreases, the wax 505 further contracts and the rod 504a is further displaced toward the valve body drive unit 502. Then, the opening / closing part 504b moves to the valve body driving part 502 side and opens the two connection ports 50a. This state is the open state of the autonomous open / close valve 50.

As described above, the autonomous open / close valve 50 operates in accordance with the temperature of the valve body drive oil charged in the valve body drive unit 502 and switches between the valve open state and the valve closed state.
Further, the valve body drive unit 502 is formed with an intake port 502a for taking in the valve body drive oil and a discharge port 502b for discharging the valve body drive oil. With this configuration, the wax 505 expands and contracts according to the temperature of the valve body drive oil taken in from the take-in port 502a, and displaces the rod 504a.

In the second embodiment, similarly to the autonomous three-way valve 51, the lubricating oil after lubricating the discharge-side bearing 14 b (see FIG. 1) of the compressor body 10 is used as the valve body driving oil for the autonomous opening / closing valve 50. Therefore, the intake port 502a of the valve body drive unit 502 is connected to the oil extraction pipe 20h as shown in FIG. Further, the discharge port 502b of the valve body driving unit 502 is connected to the oil return pipe 20i.
According to this configuration, the valve body drive unit 502 of the autonomous on-off valve 50 is filled with the lubricating oil after the bearing 14b is lubricated. The autonomous open / close valve 50 is switched between a valve open state and a valve closed state according to the temperature of the lubricating oil after the bearing 14b is lubricated.

As described above, the oil supply path according to the second embodiment includes the autonomous on-off valve 50 and the autonomous three-way valve 51, and the lubricating oil flows according to the temperature of the lubricating oil after the bearing 14b (see FIG. 1) is lubricated. The route is switched.
8 and 9 are diagrams illustrating the circulation of the lubricating oil in the second embodiment, where the solid line indicates the path through which the lubricating oil flows, and the broken line indicates the path through which the lubricating oil does not flow. A dotted arrow indicates the flow of the lubricating oil.
(A) of FIG. 8 is a figure which shows distribution | circulation of the lubricating oil when the temperature of lubricating oil is low, such as immediately after starting of the screw compressor 1a.

As described above, the oil separator 2 is not sufficiently pressurized immediately after the screw compressor 1a is started. Further, the temperature of the lubricating oil is low and the viscosity is high.
Since the temperature of the lubricating oil is low, the temperature of the lubricating oil after lubricating the bearing 14b (see FIG. 1) is also low, and the autonomous three-way valve 51 is set to the third state. That is, the third connection port 51c is closed, and the second connection port 51b and the first connection port 51a communicate with each other. In addition, the autonomous on-off valve 50 is opened.
As described above, since the oil cooler 3 has a large resistance to the flow of the lubricating oil, when the autonomous three-way valve 51 is set to the third state, the lubricating oil sent from the oil separator 2 autonomously passes through the first bypass pipe 20e. It flows into the second bypass pipe 20f via the three-way valve 51 and bypasses the oil cooler 3.
The lubricating oil flowing through the second bypass pipe 20f flows into the working chamber oil supply pipe 20c from the branch point P3, and is supplied from the working chamber oil supply port 19 of the compressor body 10 to the working chamber 13 (see FIG. 1).

Further, since the autonomous on-off valve 50 is set to the open state, the lubricating oil flowing through the working chamber oil supply pipe 20c is diverted at the branch point P1, and a part thereof flows into the bearing chamber oil supply pipe 20d. The oil is divided into the oil supply pipe 20d1 and the discharge-side oil supply pipe 20d2. Then, the lubricating oil is supplied from the suction side oil supply pipe 20d1 to the bearing chamber 15a (see FIG. 1) on the suction side via the bearing lubricating oil supply port 17a, and from the discharge side oil supply pipe 20d2 to the bearing lubricating oil supply port 17b. It is supplied to the bearing chamber 15b (see FIG. 1) on the discharge side.

The lubricating oil supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 is discharged from the discharge port 16b together with the compressed air, and flows through the discharge pipe 20a. It flows into the oil separator 2. In the oil separator 2, the lubricating oil is separated from the compressed air and stored.

Thus, when the temperature of the lubricating oil is low, such as when the screw compressor 1a is started, the lubricating oil sent from the oil separator 2 bypasses the oil cooler 3 having a large resistance to circulation and is supplied to the compressor body 10. The Therefore, even when the oil separator 2 is not sufficiently pressurized, a sufficient amount of lubrication is provided in the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10. Oil can be supplied.

(B) of FIG. 8 is a figure which shows distribution | circulation of the lubricating oil at the time of steady operation.
When the operation state of the screw compressor 1a is continued and becomes a steady operation state, the temperature of the lubricating oil rises. And if the temperature of the lubricating oil after lubricating the bearing 14b (refer FIG. 1) rises, the autonomous three-way valve 51 will be set to a 2nd state. That is, the second connection port 51b is closed, and the third connection port 51c and the first connection port 51a communicate with each other. Further, the autonomous open / close valve 50 is closed.

When the autonomous three-way valve 51 is set to the second state, the lubricating oil sent from the oil separator 2 and flowing through the cooling pipe 20b is diverted at the branch point P2, and a part flows into the first bypass pipe 20e. Then, the lubricating oil flowing through the first bypass pipe 20e flows into the third bypass pipe 20g via the autonomous three-way valve 51. The lubricating oil that has flowed through the third bypass pipe 20g flows into the bearing chamber oil supply pipe 20d at the branch point P4, and further splits into the suction-side oil supply pipe 20d1 and the discharge-side oil supply pipe 20d2. Then, the lubricating oil is supplied from the suction side oil supply pipe 20d1 to the bearing chamber 15a (see FIG. 1) on the suction side via the bearing lubricating oil supply port 17a, and from the discharge side oil supply pipe 20d2 to the bearing lubricating oil supply port 17b. It is supplied to the bearing chamber 15b (see FIG. 1) on the discharge side.

Further, the lubricating oil sent from the oil separator 2 and flowing through the cooling pipe 20b also flows into the oil cooler 3, is cooled, and flows through the working chamber oil supply pipe 20c. The autonomous three-way valve 51 is in the second state, and the second bypass pipe 20f is closed. Accordingly, the lubricating oil flowing through the working chamber oil supply pipe 20c does not flow into the second bypass pipe 20f at the branch point P3. Further, the autonomous open / close valve 50 is in a closed state, and the lubricating oil flowing through the working chamber oil supply pipe 20c does not flow into the bearing chamber oil supply pipe 20d at the branch point P1. And all the lubricating oil which distribute | circulates the working chamber oil supply pipe | tube 20c is supplied to the working chamber 13 (refer FIG. 1) from the working chamber oil supply port 19 of the compressor main body 10. FIG.

The lubricating oil supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 is discharged from the discharge port 16b together with the compressed air, and flows through the discharge pipe 20a. It flows into the oil separator 2. In the oil separator 2, the lubricating oil is separated from the compressed air and stored.

As described above, when the screw compressor 1a is in a steady operation state and the temperature of the lubricating oil rises, the lubricating oil sent from the oil separator 2 passes through the first bypass pipe 20e and the third bypass pipe 20g. It is supplied to bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10. The lubricating oil supplied to the bearing chambers 15a and 15b does not pass through the oil cooler 3 and is not cooled. Accordingly, lubricating oil having a relatively high temperature and low viscosity is supplied to the bearing chambers 15a and 15b, and high lubricating performance can be maintained.
Further, the third bypass pipe 20g is provided with a throttle 52, and the supply amount of the lubricating oil supplied to the bearing chambers 15a and 15b is suitably regulated. Therefore, power loss in the bearings 14a and 14b (see FIG. 1) can be suppressed, and a reduction in the operating efficiency of the screw compressor 1a can be prevented.

Further, the restriction 52 provided in the third bypass pipe 20g causes a flow resistance in the lubricating oil flowing through the first bypass pipe 20e, and the lubricating oil flowing through the cooling pipe 20b flows into the oil cooler 3 due to the influence of the resistance. . Then, the lubricating oil cooled by the oil cooler 3 is supplied to the working chamber 13 (see FIG. 1) of the compressor body 10. Therefore, the air compressed in the working chamber 13 can be effectively cooled.

FIG. 9A shows an operation load when, for example, the discharge pressure of air from the compressor body 10 is high, or when the rotation speed of the male rotor 11 (see FIG. 1) and the female rotor (not shown) is high. It is a figure which shows distribution | circulation of the lubricating oil in case that is high.
At this time, the temperature of the lubricating oil is higher than that during the steady operation of the screw compressor 1a, the temperature of the lubricating oil after lubricating the bearing 14b is also increased, and the autonomous three-way valve 51 is set to the first state. That is, the first connection port 51a is closed, and the third connection port 51c and the second connection port 51b communicate with each other. Note that the autonomous on-off valve 50 maintains a closed state. That is, (a) in FIG. 9 shows the flow of the lubricating oil when the autonomous three-way valve 51 is set to the first state and the autonomous opening / closing valve 50 reaches the lubricating oil temperature set to the closed state. Show.

When the autonomous three-way valve 51 is set to the first state, the lubricating oil sent from the oil separator 2 and flowing through the cooling pipe 20b does not flow into the first bypass pipe 20e at the branch point P2, but flows through the oil cooler 3. . And it cools with the oil cooler 3 and flows into the working chamber oil supply pipe | tube 20c.

The lubricating oil flowing through the working chamber oil supply pipe 20 c is diverted at the branch point P 3, and part of the lubricating oil flows into the second bypass pipe 20 f and then flows into the third bypass pipe 20 g through the autonomous three-way valve 51. Then, the lubricating oil flowing through the third bypass pipe 20g flows into the bearing chamber oil supply pipe 20d at the branch point P4, and further splits into the suction-side oil supply pipe 20d1 and the discharge-side oil supply pipe 20d2. Then, the lubricating oil is supplied from the suction side oil supply pipe 20d1 to the bearing chamber 15a (see FIG. 1) on the suction side via the bearing lubricating oil supply port 17a, and from the discharge side oil supply pipe 20d2 to the bearing lubricating oil supply port 17b. It is supplied to the bearing chamber 15b (see FIG. 1) on the discharge side.
On the other hand, the lubricating oil branched at the branch point P3 and flowing through the working chamber oil supply pipe 20c is supplied from the working chamber oil supply port 19 of the compressor body 10 to the working chamber 13 (see FIG. 1).

The lubricating oil supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 is discharged from the discharge port 16b together with the compressed air, and flows through the discharge pipe 20a. It flows into the oil separator 2. In the oil separator 2, the lubricating oil is separated from the compressed air and stored.

As described above, when the temperature of the lubricating oil becomes higher than that during the steady operation of the screw compressor 1a, the lubricating oil sent from the oil separator 2 is cooled by the oil cooler 3 and supplied to the compressor body 10. Therefore, the lubricating oil cooled by the oil cooler 3 can be supplied to the bearings 14a and 14b (see FIG. 1). As a result, the temperature of the bearings 14a and 14b can be suitably prevented from increasing, and the reliability can be maintained.
In addition, the flow rate of the lubricating oil supplied to the bearings 14a and 14b is suitably regulated by flowing through the third bypass pipe 20g provided with the throttle 52, and an increase in loss power can be suppressed.

(B) of FIG. 9 is a figure which shows distribution | circulation of lubricating oil in case a screw compressor is drive | operated in the state in which the load of the bearing became the maximum.
At this time, the temperature of the lubricating oil further increases, and the temperature of the lubricating oil after lubricating the bearing 14b also increases. And the autonomous on-off valve 50 will be in an open state, with the autonomous three-way valve 51 set to the 1st state.

When the screw compressor 1a is in this state, the lubricating oil delivered from the oil separator 2 and cooled by the oil cooler 3 is diverted at the branch point P1 when flowing through the working chamber oil supply pipe 20c, and a part thereof is a bearing chamber. It flows into the oil supply pipe 20d. Lubricating oil flowing through the bearing chamber oil supply pipe 20d is divided into a suction-side oil supply pipe 20d1 and a discharge-side oil supply pipe 20d2. Then, the lubricating oil is supplied from the suction side oil supply pipe 20d1 to the bearing chamber 15a (see FIG. 1) on the suction side via the bearing lubricating oil supply port 17a, and from the discharge side oil supply pipe 20d2 to the bearing lubricating oil supply port 17b. It is supplied to the bearing chamber 15b (see FIG. 1) on the discharge side.

On the other hand, the lubricating oil branched at the branch point P1 and flowing through the working chamber oil supply pipe 20c is supplied from the working chamber oil supply port 19 of the compressor body 10 to the working chamber 13 (see FIG. 1).

The lubricating oil supplied to the working chamber 13 (see FIG. 1) and the bearing chambers 15a and 15b (see FIG. 1) of the compressor body 10 is discharged from the discharge port 16b together with the compressed air, and flows through the discharge pipe 20a. It flows into the oil separator 2. In the oil separator 2, the lubricating oil is separated from the compressed air and stored.

Thus, when the screw compressor 1a is operated with the load on the bearings 14a and 14b (see FIG. 1) being maximized, the lubricating oil can be supplied to the bearings 14a and 14b by bypassing the throttle 52. Therefore, the supply amount of the lubricating oil to the bearings 14a and 14b can be increased, and the bearings 14a and 14b having the maximum load can be sufficiently lubricated with the lubricating oil.
Further, the low-temperature lubricating oil cooled by the oil cooler 3 can be supplied to the bearings 14a and 14b. Therefore, the bearings 14a and 14b that have become high temperature under a large load can be effectively cooled with the lubricating oil.

As described above, the screw compressor 1a according to the second embodiment lubricates the oil supply passage for supplying the lubricating oil to the working chamber 13 (see FIG. 1) of the compressor body 10 and the bearing chambers 15a and 15b (see FIG. 1). The oil supply route for supplying oil is configured to be an independent route. With this configuration, the amount of lubricating oil supplied to the bearing chambers 15a and 15b can be adjusted without affecting the amount of lubricating oil supplied to the working chamber 13.
In addition, a throttle 52 is provided in the oil supply path for supplying the lubricating oil to the bearing chambers 15a and 15b so that the supply amount of the lubricating oil supplied to the bearings 14a and 14b (see FIG. 1) can be regulated. Thereby, it is possible to prevent a decrease in operating efficiency due to an increase in power loss.
In addition, an oil supply path that bypasses the throttle 52 and supplies lubricating oil to the bearings 14a and 14b is provided. With this configuration, a sufficient amount of lubricating oil can be supplied to the bearings 14a and 14b as necessary. Therefore, the lubrication performance for the bearings 14a and 14b can be maintained.
And it was set as the structure which uses the autonomous three-way valve 51 and the autonomous on-off valve 50 for switching of the path | route which lubricating oil distribute | circulates.
According to this configuration, the route through which the lubricating oil flows can be switched at the temperature of the lubricating oil without being electrically controlled.
Accordingly, it is possible to prevent malfunction of the screw compressor 1a due to failure of electronic equipment such as a control device.
Further, since the bearing temperature sensor 15c (see FIG. 1) for measuring the temperature of the bearing 14b (see FIG. 1) is not necessary, the cost of the screw compressor 1 (see FIG. 1) can be reduced.

In addition, this invention is not limited to an above-described Example. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.
Further, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment.

For example, as shown in FIG. 2, in the first embodiment, the first bypass pipe 20e, the second bypass pipe 20f, and the third bypass pipe 20g are connected by a three-way valve 21. However, this configuration is not limited. For example, the first bypass pipe 20e provided with the on-off valve, the second bypass pipe 20f provided with the on-off valve, and the third bypass pipe 20g provided with the on-off valve may be connected. In the case of this configuration, the control device 4 can appropriately control the on-off valve provided in each bypass pipe, thereby switching the route of the lubricating oil similarly to the three-way valve 21.
For example, when all the bypass pipe opening / closing valves are opened, the three-way valve 21 is set to the first state, and when all the bypass pipe opening / closing valves are closed, the three-way valve is set to the second state. Is equivalent to 21.
Further, when the on-off valve of the first bypass pipe 20e is closed and the on-off valve of the second bypass pipe 20f and the on-off valve of the third bypass pipe 20g are opened, it is equivalent to the three-way valve 21 set in the third state. Become.
Thus, it can replace with the three-way valve 21, and can also be set as the structure provided with an on-off valve in each bypass pipe.

Similarly, in the second embodiment, instead of the autonomous three-way valve 51 (see FIG. 6), the autonomous on-off valve 50 (see FIG. 6) is connected to the first bypass pipe 20e, the second bypass pipe 20f, and the third bypass pipe 20g, respectively. 7 (b)). In this case, the function similar to that of the autonomous three-way valve 51 can be provided by appropriately changing the operation of the valve body with respect to the temperature of the lubricating oil by the opening / closing valve of each bypass pipe.
For example, an autonomous on-off valve 50 that closes when the lubricating oil is hot is provided in the first bypass pipe 20e, and an autonomous on-off valve 50 that closes when the lubricating oil is low is provided in the third bypass pipe 20g. And it is sufficient. Furthermore, the second bypass pipe 20f is closed at a temperature lower than the temperature at which the autonomous open / close valve 50 of the first bypass pipe 20e is closed and higher than the temperature at which the autonomous open / close valve 50 of the third bypass pipe 20g is closed. What is necessary is just to set it as the structure provided with the autonomous on-off valve 50 to valve.
Thus, it can replace with the autonomous three-way valve 51, and can also be set as the structure provided with the autonomous on-off valve 50 in each bypass pipe.
Further, the structures of the autonomous three-way valve 51 and the autonomous opening / closing valve 50 shown in FIG. 7 are not limited.

In the second embodiment, an electric on-off valve may be provided instead of the autonomous on-off valve 50 (see FIG. 6). In this case, a bearing temperature sensor 15c (see FIG. 1) and a control device 4 (see FIG. 1) are provided, and the control device 4 controls the electric on-off valve based on the temperature of the bearing 14b measured by the bearing temperature sensor 15c. What is necessary is just composition.

In addition, the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the invention.

Claims (4)

1. A compressor body in which a working chamber in which a pair of male and female rotors rotate to compress gas and a bearing chamber provided with a bearing that supports the rotor are formed;
   A first conduit for supplying a lubricating liquid to the working chamber;
   A second conduit for supplying the liquid to the bearing chamber;
   Cooling means for cooling the liquid discharged from the working chamber;
   A third conduit for supplying the liquid discharged from the working chamber to the cooling means;
   A bypass line bypassing the cooling means;
   A flow rate adjusting means for adjusting the flow rate of the liquid provided in the second conduit,
   The first conduit supplies the liquid cooled by the cooling means to the working chamber,
   The second pipe branches from the first pipe and supplies the liquid cooled by the cooling means to the bearing chamber;
   The bypass pipe includes a first bypass pipe branched from the third pipe, a second bypass pipe branched from the first pipe between the branch point of the second pipe and the cooling means, A third bypass pipe branched from the second pipe line between the flow rate adjusting means and the bearing chamber is connected,
   A screw compressor, comprising: opening and closing means for opening and closing each of the first bypass pipe, the second bypass pipe, and the third bypass pipe.
2. The screw compressor according to claim 1, further comprising second flow rate adjusting means for adjusting a flow rate of the liquid flowing through the third bypass pipe.
3. 3. The screw compressor according to claim 1 or 2, wherein at least one of the opening / closing means and the flow rate adjusting means operates based on a temperature of the bearing.
4. The screw compressor according to claim 3, wherein the temperature of the bearing is a temperature of the liquid after the bearing is lubricated.

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