CN111279082B

CN111279082B - Screw compressor

Info

Publication number: CN111279082B
Application number: CN201880072556.8A
Authority: CN
Inventors: 野口透; 坂口广宣; 今城贵德; 田中孝二
Original assignee: Shengang Compressor Co ltd
Current assignee: Shengang Compressor Co ltd
Priority date: 2017-11-09
Filing date: 2018-10-25
Publication date: 2022-04-15
Anticipated expiration: 2038-10-25
Also published as: JP2019085970A; WO2019093138A1; JP6775482B2; CN111279082A

Abstract

A screw compressor (1) is provided with a male rotor (151), a female rotor (152), a rotor case (110), a main oil supply port (112) provided in the rotor case (110) so as to open to a discharge side space of a female rotor chamber (S2), and an additional oil supply port (113) provided in the rotor case (110) on the outlet side of the main oil supply port (112). The screw compressor (1) is further provided with: a solenoid valve (50) that allows or blocks the supply of oil from the additional oil supply port (113); a load detection unit (61) that detects a load acting on the screw compressor (1); and an additional fuel supply control unit (62) that controls the solenoid valve (50) so that fuel supply from the additional fuel supply port (113) is permitted when the load detected by the load detection unit (61) is greater than or equal to a predetermined value, and so that fuel supply from the additional fuel supply port (113) is blocked when the load detected by the load detection unit (61) is less than the predetermined value.

Description

Screw compressor

Technical Field

The present invention relates to an oil supply type screw compressor.

Background

For example, patent document 1 discloses an oil-feed screw compressor in which heat exchange between gas and oil during compression is promoted by devising the arrangement of injection nozzles (oil feed ports). In the oil-feed screw compressor of patent document 1, the injection direction from the injection nozzle into the compression chamber (rotor chamber) is directed in the opposite direction to the rotation direction of the screw rotor. This ensures that the time during which the oil flies in the gas in the compression chamber is long, and promotes heat exchange between the gas and the oil.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 9-151870.

Disclosure of Invention

Problems to be solved by the invention

In the oil-feed screw compressor, since oil is mixed in during compression for the purpose of cooling the compressed gas as described above, a power loss other than the compression power of the gas, such as a power loss due to stirring of the oil and a power loss due to viscosity of the oil existing in a narrow gap in the compression chamber, occurs. If this power loss becomes large, the specific power, which is an index of the energy efficiency of the compressor, becomes poor. In particular, when the amount of oil is large, the specific power is significantly deteriorated, and therefore, the amount of oil is desirably small from the viewpoint of suppressing power loss. However, if the amount of oil is too small, the temperature of the compressed gas increases, the compression efficiency decreases, and the life of each component constituting the compression mechanism decreases. Therefore, the compressor needs to be driven at an appropriate oil supply amount.

The appropriate amount of oil supply varies depending on the load acting on the compressor. The load acting on the compressor varies depending on, for example, the temperature of the supplied oil and the rotational speed of the screw rotor. However, in patent document 1, such oil supply according to load is not particularly studied, and there is room for improvement.

The invention provides a screw compressor which can reduce power loss and improve cooling performance by supplying oil to a proper position in a timely manner according to load.

Means for solving the problems

The invention according to claim 1 provides a screw compressor including: a male rotor; a female rotor having more teeth than the male rotor and meshing with the male rotor; a rotor housing having a suction port and a discharge port, and defining a male rotor chamber for accommodating the male rotor and a female rotor chamber for accommodating the female rotor; a main body oil supply port provided in the rotor case so as to open to the discharge side space of the female rotor chamber; an additional fuel supply port provided in the rotor case at the outlet side of the main fuel supply port; an additional fuel supply adjusting mechanism for allowing or blocking the supply of fuel from the additional fuel supply port; a load detection unit that detects a load acting on the screw compressor; and an additional fuel supply control unit that controls the additional fuel supply adjustment mechanism so as to allow the fuel supply from the additional fuel supply port when the load detected by the load detection unit is equal to or greater than a predetermined value, and to shut off the fuel supply from the additional fuel supply port when the load detected by the load detection unit is less than the predetermined value.

According to this configuration, the main body oil supply port is provided so as to open to the discharge side space of the female rotor chamber, and therefore oil is mainly supplied to the female rotor. The female rotor has a larger number of teeth than the male rotor, and therefore has a lower rotational speed. Therefore, the power for stirring the oil can be reduced as compared with the case where the oil is mainly supplied to the male rotor. Further, since the additional fuel fill port is provided closer to the outlet side than the main fuel fill port, the stirring power corresponding to the cooling effect can be reduced as compared with the case of supplying the oil to the suction side than the main fuel fill port, and the leakage prevention of the gas required particularly on the high pressure side (i.e., closer to the outlet side) (i.e., the prevention of the compression leakage to the low pressure side) can be realized. Further, by providing two fuel supply ports, namely, the main fuel supply port and the additional fuel supply port, and controlling the additional fuel supply adjustment mechanism by the additional fuel supply control unit in accordance with the load detected by the load detection unit, the amount of fuel supply is increased only when the load is large, thereby achieving both suppression of power loss and improvement of cooling performance. Thus, by supplying oil to an appropriate portion at an appropriate timing, both the suppression of power loss and the cooling performance can be achieved. Here, the load is a general term of various loads acting on the screw compressor, and includes various factors that affect the energy efficiency (specific power) of the screw compressor, such as the rotational speed of at least one of the male rotor and the female rotor, the current of a motor that drives at least one of the male rotor and the female rotor, the ambient temperature, the temperature of the supplied oil, and the temperature of the discharged gas.

The present invention may further include: a bearing for supporting the male rotor or the female rotor at a position closer to the discharge port of the rotor case; a bearing oil drain line for transferring oil drained from the bearing; and a bearing oil drain port which is an outlet of the bearing oil drain line and is provided so as to open to the discharge-side space in the rotor case; in the rotor case, the additional oil supply port is provided so as to open to the male rotor chamber or the female rotor chamber.

According to this configuration, since the oil (bearing drain oil) used in the bearing can be supplied into the discharge-side space of the rotor housing via the bearing drain line and the bearing drain port, the compressed gas mixed in the oil is not wasted. Further, since the additional oil supply port is provided on the male rotor chamber side or the female rotor chamber side, the oil is supplied from the additional oil supply port only to one of the male rotor and the female rotor. Therefore, excessive supply of oil can be suppressed, and power loss due to stirring of the excessive oil can be suppressed.

The additional oil supply port may be provided so as to open to the male rotor chamber.

According to this configuration, since the oil can be additionally supplied to the male rotor when the load is large, the male rotor can be cooled at a proper time. The male rotor has fewer teeth than the female rotor, so the speed of rotation is faster. Therefore, the bearing temperature of the male rotor is more likely to rise than that of the female rotor, and particularly, the bearing temperature is most likely to rise on the injection port side of the male rotor. If the bearing temperature rises excessively, the bearing may be damaged. However, when the load is large, that is, when the bearing temperature on the outlet side of the male rotor is likely to increase, the male rotor can be efficiently cooled by the additional oil supply from the additional oil supply port provided on the outlet side of the main body oil supply port, so that the bearing temperature can be reduced together by heat conduction from the male rotor to the bearing, and damage to the bearing on the outlet side of the male rotor can be suppressed.

The additional oil supply port may be provided so as to open to the female rotor chamber, and the main body oil supply port may not be provided on the male rotor chamber side.

According to this configuration, the main body oil supply port is not provided on the male rotor chamber side, and the additional oil supply port is provided on the female rotor chamber side. That is, the main body oil supply port having the largest amount of oil supply is not provided on the male rotor chamber side, and the additional oil supply port is also provided on the female rotor chamber side. Since oil can be supplied to the female rotor, the stirring power of the oil can be reduced from the viewpoint of the rotational speed as described above. Further, since the male rotor meshes with the female rotor, the male rotor chamber communicates with the female rotor chamber, and even if the structure is such that oil is supplied only to the female rotor chamber side, minimum oil is supplied to the male rotor chamber side.

The additional oil supply port may be provided so as to open into the female rotor chamber, the bearing drain port may be provided so as to open into the female rotor chamber, and the main body oil supply port and the bearing drain port may not be provided on the male rotor chamber side.

According to this configuration, the oil is supplied only to the female rotor chamber side, so that the stirring power of the oil can be reduced and the bearing oil can be effectively used. Further, as described above, the male rotor chamber and the female rotor chamber communicate with each other, and even if the structure is such that oil is supplied only to the female rotor chamber side, minimum amount of oil is supplied to the male rotor chamber side.

The invention of claim 2 provides an oil supply method for a screw compressor, the screw compressor comprising: a male rotor; a female rotor having more teeth than the male rotor and meshing with the male rotor; a rotor housing having a suction port and a discharge port, and defining a male rotor chamber for accommodating the male rotor and a female rotor chamber for accommodating the female rotor; a main body oil supply port provided so as to open to the discharge side space of the female rotor chamber; and an additional oil supply port provided in a discharge side space on the discharge side in the direction of the rotation axis of the female rotor, with respect to the main oil supply port; the method of supplying oil to the screw compressor is characterized in that the oil is supplied from the main body oil supply port to the female rotor chamber, the oil is supplied from the additional oil supply port to the male rotor chamber or the female rotor chamber, the load acting on the screw compressor is detected, and the additional oil supply is controlled so that the oil supply from the additional oil supply port is allowed when the detected load is greater than or equal to a predetermined value, and the oil supply from the additional oil supply port is blocked when the detected load is less than the predetermined value.

Effects of the invention

According to the present invention, the main fuel fill port and the additional fuel fill port are provided at predetermined positions, the additional fuel fill adjustment mechanism is controlled by the additional fuel fill control unit based on the load detected by the load detection unit, and the fuel fill amount is increased only when the load is large, thereby achieving both the suppression of power loss and the improvement of cooling performance.

Drawings

Fig. 1 is a system diagram of a screw compressor according to embodiment 1 of the present invention.

Fig. 2 is a schematic cross-sectional view showing the inside of the female rotor chamber of fig. 1.

Fig. 3 is a block diagram of the control device of fig. 1.

Fig. 4 is a system diagram of the screw compressor according to embodiment 2.

Fig. 5 is a system diagram of the screw compressor according to embodiment 3.

Fig. 6 is a system diagram of the screw compressor according to embodiment 4.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

(embodiment 1)

Fig. 1 is a system diagram including an oil supply type screw compressor 1 (hereinafter, referred to as a screw compressor 1) according to embodiment 1. The screw compressor 1 includes a compressor body 10, and air is sucked from the outside by the compressor body 10, compressed inside, and discharged.

The compressor body 10 includes a compression unit 100 and a motor 200 for driving the compression unit 100. The outer package of the compression unit 100 is composed of a rotor housing 110, a bearing housing 120, and a bearing cover 130.

The rotor case 110 is disposed adjacent to the motor 200. The rotor case 110 has a closed wall 111 having a through hole 111a at one end and an open, i.e., a substantially bottomed cylindrical shape at the other end. A screw rotor 150 is accommodated in the rotor case 110, the screw rotor 150 is composed of a male rotor 151 and a female rotor 152, and the female rotor 152 is engaged with the male rotor 151 and has a larger number of teeth than the male rotor 151. In the present embodiment, although not shown in detail, the male rotor 151 has 4 teeth and the female rotor 152 has 6 teeth, for example.

In the rotor case 110, a space in which the male rotor 151 is disposed is referred to as a male rotor chamber S1, and a space in which the female rotor 152 is disposed is referred to as a female rotor chamber S2. The male rotor chamber S1 and the female rotor chamber S2 are defined by the rotor case 110. However, the definition here means that the male rotor chamber S1 and the female rotor chamber S2 are partially or entirely partitioned from the outside. In detail, the male rotor chamber S1 and the female rotor chamber S2 are spaces surrounded by the rotor housing 110 and the bearing housing 120. In addition, the male rotor chamber S1 and the female rotor chamber S2 communicate with each other at a position where the male rotor 151 meshes with the female rotor 152.

A shaft member 151a serving as a rotation shaft of the male rotor 151 extends from one end of the male rotor 151. The shaft member 151a extends outward of the male rotor chamber S1 through the through hole 111a of the closing wall 111 to the motor 200, and is mechanically connected to the motor 200. Similarly, a shaft member 151b serving as a rotation shaft of the male rotor 151 extends from the other end of the male rotor 151. The shaft member 151b extends outward of the male rotor chamber S1 through the opening at the other end of the rotor housing 110, and is stopped in the bearing housing 120.

A shaft member 152a serving as a rotation shaft of the female rotor 152 extends from one end of the female rotor 152. The shaft member 152a extends outward of the female rotor chamber S2 through the through hole 111b of the closing wall 111, and is stopped in a recess 111c of the rotor case 110, which will be described later. Similarly, a shaft member 152b serving as a rotation shaft of the female rotor 152 extends from the other end of the female rotor 152. The shaft member 152b extends outward of the female rotor chamber S2 through an opening at the other end of the rotor housing 110, and is stopped in the bearing housing 120.

The

shaft members

151a, 151b and the

shaft members

152a, 152b extend in parallel with each other in a horizontal plane, and the male rotor 151 and the female rotor 152 also extend in the same direction (the left-right direction in fig. 1). That is, the compressor body 10 of the present embodiment is a horizontal type in which the screw rotor 150 is horizontally disposed. However, the arrangement of the male rotor 151 and the female rotor 152 is not limited to this, and any arrangement may be adopted. For example, the arrangement may be a vertical type in which the screw rotor 150 is vertically arranged, or an inclined type in which the rotation axes of the male rotor 151 and the female rotor 152 are arranged to be inclined from the horizontal plane.

Bearing housing 120 is adjacent to rotor housing 110, and is disposed on the opposite side of rotor housing 110 from motor 200 in the rotation axis direction (the left-right direction in fig. 1) of screw rotor 150. The bearing housing 120 has a closing wall 121 having through

holes

121a and 121b for inserting the

shaft members

151b and 152b at one end, and has a substantially bottomed cylindrical shape with the other end opened. At the other end of the bearing housing 120, a bearing cap 130 is mounted, and the opening at the other end is closed by the bearing cap 130.

Bearings

161 and 162 are accommodated in a space enclosed by bearing housing 120 and bearing cover 130. The

bearings

161 and 162 axially support the

shaft members

151b and 152b, respectively.

Bearings

163 and 164 are disposed between motor 200 and rotor case 110. Specifically, the

bearings

163 and 164 are disposed in a recess 111c provided in the blocking wall 111 of the rotor case 110, and axially support the

shaft members

151a and 152a, respectively.

With the above configuration, if the motor 200 is operated, the compressor body 10 transmits rotational power to the male rotor 151 via the shaft member 151a, the male rotor 151 and the female rotor 152 mesh with each other as the male rotor 151 rotates, the female rotor 152 also rotates, and air is compressed by the rotation of both the

rotors

151 and 152. At this time, air is sucked from a suction port 115 (see fig. 2) on the motor 200 side and on the upper portion of the rotor case 110, and is discharged from a discharge port 116 (see fig. 2) on the bearing case 120 side and below the rotor case 110.

When compression is performed by the compression unit 100, oil is supplied into the rotor case 110 from the viewpoint of lubrication of the screw rotor 150, cooling of compressed air, sealing performance accompanying compression, and the like. As will be described in detail later, the rotor case 110 of the present embodiment is provided with a main oil supply port 112, an additional oil supply port 113, and a bearing drain port 114. The oil supplied through the main body oil supply port 112, the additional oil supply port 113, and the bearing drain port 114 is discharged together with the compressed air, and is sent to the oil separation/recovery unit 20 through the flow passage (pipe) 5 a.

The oil separation/recovery unit 20 includes a separator 21 and an oil tank 22. The separator 21 separates oil from the compressed air containing oil. The oil separated by the separator 21 is stored in the oil tank 22. A temperature sensor 23 is attached to the oil tank 22, and the temperature of the oil inside can be measured by the temperature sensor 23. The screw compressor 1 also includes a temperature sensor 24, and the temperature sensor 24 measures an ambient temperature corresponding to an ambient temperature that is an ambient temperature of an environment in which the screw compressor is installed. The oil tank 22 is connected to the oil cooler 30 via a flow path (pipe) 5b, and the oil accumulated in the oil tank 22 is sent to the oil cooler 30 via the flow path 5 b. The oil-separated compressed air is sent to a supply destination via a flow path (pipe) not shown.

The oil cooler 30 is a heat exchanger that exchanges heat between a heat carrier such as cold water and oil. Here, the oil is cooled by obtaining cold heat from a heat carrier such as cold water. However, the form of the oil cooler 30 is not limited to such a heat exchanger, and may be any form. The oil cooler 30 is connected to the oil filter 40 via a flow path (pipe) 5c, and the oil cooled by the oil cooler 30 is sent to the oil filter 40 via the flow path 5 c.

The oil filter 40 is a filter for filtering unnecessary substances such as dirt from oil. The oil filter 40 is connected to the

bearings

161 and 162, the main body oil supply port 112, and the additional oil supply port 113 via the flow passages (pipes) 5d, 5e, and 5f, and the oil from which the unnecessary matter has been removed by the oil filter 40 is sent to the

bearings

161 and 162 and the screw rotor 150 via the flow passages (pipes) 5d, 5e, and 5 f. In particular, the electromagnetic valve 50 is provided as additional fuel supply adjusting means in the flow path (pipe) 5e connecting the oil filter 40 and the additional fuel supply port 113, and the supply of fuel from the additional fuel supply port 113 to the screw rotor 150 can be allowed or blocked by opening and closing the electromagnetic valve 50. Since fig. 1 schematically illustrates the description, the flow paths (pipes) 5d, 5e, and 5f are illustrated as being connected to the oil filter 40, but the flow paths (pipes) 5d, 5e, and 5f actually branch from one flow path (pipe) connected to the oil filter 40.

The oil (bearing drain) lubricated and cooled by the

bearings

161 and 162 located closer to the discharge port 116 can flow out into the space enclosed by the bearing housing 120 and the bearing cover 130. This space is connected to the bearing drain port 114 of the rotor case 110 via a flow path (bearing drain line) 5g as an internal flow path of the compression unit 100. That is, an outlet (bearing drain port) 114 of the flow path (bearing drain line) 5g is provided so as to open to a discharge-side space in the rotor case 110 (the male rotor chamber S1 or the female rotor chamber S2) described later, and oil (bearing drain) is supplied into the discharge-side space of the rotor case 110 through the flow path 5 g. Although not shown, oil is supplied to the

bearings

163 and 164 on the side closer to the suction port 115, and the oil supplied to the

bearings

163 and 164 for lubrication and cooling penetrates into the male rotor chamber S1 and the female rotor chamber S2 through the through

holes

111a and 111 b.

Fig. 2 is a schematic sectional view showing the inside of the female rotor chamber S2. Fig. 2 is a schematic view, and therefore, there are cases different from the actual size and position. The one-dot chain line in fig. 2 indicates the rotation axis of the female rotor 152. Suction port 115 is provided so as to communicate with a space before closing by male rotor 151 and female rotor 152 in rotor case 110. Further, the discharge port 116 is provided so as to communicate with a closed space formed by the male rotor 151 and the female rotor 152 in the rotor case 110. Hereinafter, the space before closing the male rotor chamber S1 or the female rotor chamber S2 is referred to as a suction-side space, and the space after closing the male rotor chamber S1 or the female rotor chamber S2 is referred to as a discharge-side space. Further, suction port 115 is provided at one end (left end in fig. 2) of screw rotor 150, and discharge port 116 is provided at the other end (right end in fig. 2) of screw rotor 150. Hereinafter, one end portion side of the screw rotor 150 in the rotor rotation axis direction is referred to as an intake side, and the other end portion side is referred to as an ejection side.

In the present embodiment, all of the main body oil supply port 112, the additional oil supply port 113, and the bearing oil drain port 114 are provided so as to open into the discharge side space of the female rotor chamber S2. Of these

oil supply ports

112 and 113 and the oil drain port 114, the bearing oil drain port 114 is provided closest to the suction port side (left side in fig. 2), the additional oil supply port 113 is provided closest to the discharge port side (right side in fig. 2), and the main body oil supply port 112 is provided between the additional oil supply port 113 and the bearing oil drain port 114. Preferably, all of the main body oil supply port 112, the additional oil supply port 113, and the bearing oil drain port 114 are provided below the rotor rotation axis in the discharge side space. More preferably, the main oil supply port 112, the additional oil supply port 113, and the bearing drain port 114 are all provided directly below the rotation axis of the female rotor 152. However, the arrangement of the

oil supply ports

112 and 113 and the drain port 114 is not limited to the above. In particular, the additional filler inlet 113 may be provided at any position around the rotation axis as long as it is closer to the discharge port than the main filler inlet 112. For example, the additional fuel fill port 113 may be provided so as to open into the suction-side space on the discharge port side of the main fuel fill port 112 in consideration of ease of handling of the flow path 5 g.

The screw compressor 1 is further provided with a control device 60. The control device 60 is constructed of hardware including a storage device such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and software installed therein.

The control device 60 controls each component of the screw compressor 1, and particularly receives signals relating to the rotation speed of the motor 200, the oil temperature from the temperature sensor 23, and the ambient temperature from the temperature sensor 24, and controls the opening and closing of the electromagnetic valve 50 based on these signals.

As shown in fig. 3, the control device 60 includes: a load detection unit 61 that detects a load acting on the screw compressor 1 (a load related to compression by the screw rotor 150); and an additional oil supply control unit 62 for controlling opening and closing of the solenoid valve 50 in accordance with the load. Here, the load is a general term of various loads acting on the screw compressor 1, and is, for example, various factors that affect the energy efficiency (specific power) of the screw compressor 1, such as the rotation speed of the screw rotor 150, the current of the motor 200 driving the screw rotor 150, the ambient temperature, the temperature of the supplied oil, and the temperature of the discharged gas.

In the present embodiment, the load detection unit 61 detects the load based on the rotation speed from the motor 200, the oil temperature from the temperature sensor 23, and the ambient temperature from the temperature sensor 24. Specifically, the greater the values of the rotation speed from the motor 200, the oil temperature from the temperature sensor 23, and the ambient temperature from the temperature sensor 24, the greater the load detected. Since the cooling amount of the compressed air in the rotor case 110 needs to be increased as the load is larger, a larger amount of oil supply is required in the rotor case 110. However, the load detection may take into consideration not only these values but also the current flowing through the motor 200 and the temperature of the compressed air discharged from the compressor body 10. That is, in addition to the above, a larger load may be detected as the current flowing through the motor 200 and the temperature of the compressed air discharged from the compressor body 10 are higher.

The additional fuel supply control unit 62 controls the electromagnetic valve 50 such that the fuel supply from the additional fuel supply port 113 is permitted (the electromagnetic valve 50 is opened) when the load detected by the load detection unit 61 is equal to or greater than a predetermined value, and the fuel supply from the additional fuel supply port 113 is blocked (the electromagnetic valve 50 is closed) when the load detected by the load detection unit 61 is less than the predetermined value. The threshold value for determining the load for opening and closing the solenoid valve 50 differs depending on the performance of the compressor body 10 and the like. For example, the threshold value of the load may be determined from the viewpoints of heat resistance, mechanical durability, and the like of the elements (the screw rotor 150, the bearings 161 to 164, and the like) constituting the compressor main body 10.

According to the screw compressor 1 of the present embodiment, there are the following advantages.

(1) The main body oil supply port 112 is provided so as to open to the discharge side space of the female rotor chamber S2, and therefore supplies oil to the female rotor 152. The female rotor 152 has a larger number of teeth than the male rotor 151, and therefore has a smaller rotational speed. Therefore, power for stirring the oil can be reduced as compared with the case of supplying the oil to the male rotor 151. Further, since the additional oil supply port 113 is provided on the outlet side (the right side in fig. 2) of the screw rotor 150 in the rotor rotation axis direction with respect to the main body oil supply port 112, the stirring power corresponding to the cooling effect can be reduced as compared with the case of supplying oil to the suction side with respect to the main body oil supply port 112, and the leakage prevention of the compressed air (i.e., the prevention of the compression leakage to the low pressure side) which is required particularly on the high pressure side (i.e., the outlet side) can be realized. Further, by providing two fuel supply ports, i.e., the main fuel supply port 112 and the additional fuel supply port 113, and controlling the solenoid valve 50 by the additional fuel supply control unit 62 in accordance with the load detected by the load detection unit 61, the fuel supply amount is increased only when the load is large, thereby achieving both suppression of power loss and improvement of cooling performance. Thus, by supplying oil to an appropriate portion at an appropriate timing, both the suppression of power loss and the cooling performance can be achieved.

(2) The male rotor chamber S1 side is not provided with the main oil supply port, and the female rotor chamber S2 side is provided with the additional oil supply port 113. Accordingly, the main body oil supply and the additional oil supply can be performed to the female rotor chamber S2 side without performing the main body oil supply with the largest amount of oil supply to the male rotor chamber S1 side, so that the stirring power of the oil can be reduced from the viewpoint of the rotational speed as described above. Further, since the male rotor chamber S1 communicates with the female rotor chamber S2, even if the structure is such that oil is supplied only to the female rotor chamber S2 side, minimum oil is supplied to the male rotor chamber S1.

(embodiment 2)

The screw compressor 1 according to embodiment 2 shown in fig. 4 differs from embodiment 1 in the position of the additional oil supply port 113. The configuration other than this is the same as that of the screw compressor 1 according to embodiment 1 of fig. 1. Therefore, the same reference numerals are given to the same portions as those of the structure shown in fig. 1, and the description thereof is omitted.

In the present embodiment, the additional oil supply port 113 is provided so as to open to the male rotor chamber S1. Preferably, the additional oil supply port 113 is provided in a discharge side space of the male rotor chamber S1 directly below the rotation axis of the male rotor 151. The structure in which the main body oil supply port 112 and the bearing oil drain port 114 are provided so as to open into the discharge side space of the female rotor chamber S2 and the additional oil supply port 113 is provided so as to open into the male rotor chamber S1 as in the present embodiment is suitable for the small-sized screw compressor 1. The screw compressor 1 is small, and for example, the outer diameters of the male rotor 151 and the female rotor 152 are 100mm or less. The closer the main body fuel supply port 112, the bearing drain port 114, and the additional fuel supply port 113 are to each other, the more severe the restrictions on processing and assembly (restrictions on manufacturing) become. By providing the additional oil supply port 113, which requires the passage 5e as an external pipe to be connected via the rotor case 110, to the male rotor chamber S1, the manufacturing constraints in the case of a small size can be alleviated. Further, although the additional oil supply to the male rotor chamber S1 is performed, the amount of oil supply itself is small compared to the large size, and therefore, the deterioration of the specific power is suppressed.

According to the present embodiment, since the oil can be additionally supplied to the male rotor chamber S1 when the load is large, the male rotor 151 can be cooled at a proper time. The male rotor 151 has fewer teeth than the female rotor 152, and therefore has a higher rotational speed. Therefore, the bearing temperature is more likely to rise than the female rotor 152. In particular, the temperature of the bearing 161 on the side closer to the discharge port is most likely to rise, and if the temperature rises excessively, the bearing 161 may be damaged. However, when the load is large, that is, when the temperature of the male rotor 151 is likely to rise, the male rotor 151 can be efficiently cooled by additional oil supply from the additional oil supply port 113 provided on the discharge port side of the main oil supply port 112, so the temperature of the bearing 161 can be also lowered together by heat conduction from the male rotor 151 to the bearing 161, and damage to the bearing 161 on the side closer to the discharge port 116 of the male rotor can be suppressed.

Alternatively, the additional oil supply port 113 may be provided not only on the male rotor chamber S1 side but also on the female rotor chamber S2 side. However, the additional oil supply port 113 is preferably provided on the male rotor chamber S1 side or the female rotor chamber S2 side. In other words, the additional oil supply port 113 is preferably provided not on both the male rotor chamber S1 side and the female rotor chamber S2 side but on one side.

Thus, since the oil (bearing drain) used by the

bearings

161 and 162 on the side closer to the discharge port 116 can be supplied into the discharge-side space of the rotor case 110 through the flow path 5g serving as the bearing drain line and the bearing drain port 114, the compressed gas mixed in the oil is not wasted. Further, since the additional oil supply port 113 is provided on the male rotor chamber S1 side or the female rotor chamber S2 side, oil is supplied from the additional oil supply port 113 to only one of the male rotor 151 and the female rotor 152. Therefore, excessive supply of oil can be suppressed, and power loss due to stirring of the excessive oil can be suppressed.

(embodiment 3)

The screw compressor 1 according to embodiment 3 shown in fig. 5 differs from embodiment 1 in the position of the bearing oil drain port 114. The configuration other than this is the same as that of the screw compressor 1 according to embodiment 1 of fig. 1. Therefore, the same reference numerals are given to the same portions as those of the structure shown in fig. 1, and the description thereof is omitted.

In the present embodiment, the bearing oil drain port 114 is provided so as to open to the male rotor chamber S1. Preferably, the bearing oil drain port 114 is provided so as to open to a discharge-side space of the male rotor chamber S1 directly below the rotation axis of the male rotor 151. The structure in which the main oil supply port 112 and the additional oil supply port 113 are provided so as to open into the female rotor chamber S2 and the bearing oil drain port 114 is provided so as to open into the male rotor chamber S1 as in the present embodiment is suitable for the large screw compressor 1. The large screw compressor 1 means that the outer diameters of the male rotor 151 and the female rotor 152 exceed 100mm, for example. In order to suppress the deterioration of the specific power, the oil is desirably supplied to the female rotor chamber S1, but the larger the size, the more likely the sealability of the male rotor chamber S1 is deteriorated. By supplying the bearing drain oil having the smallest oil amount among the main body oil supply, the bearing drain oil, and the additional oil supply to the male rotor chamber S1, it is possible to prevent deterioration of the sealing property of the male rotor chamber S1 while suppressing deterioration of the specific power even in a large size.

In this way, of the main body oil supply port 112, the additional oil supply port 113, and the bearing drain port 114, only the bearing drain port 114 may be provided on the male rotor chamber S1 side. Alternatively, the bearing oil drain port 114 may be provided in both the male rotor chamber S1 and the female rotor chamber S2.

(embodiment 4)

The screw compressor 1 according to embodiment 4 shown in fig. 6 differs from embodiment 1 in the positions of the additional oil supply port 113 and the bearing oil drain port 114. The configuration other than this is the same as that of the screw compressor 1 according to embodiment 1 of fig. 1. Therefore, the same reference numerals are given to the same portions as those of the structure shown in fig. 1, and the description thereof is omitted.

In the present embodiment, the additional oil supply port 113 and the bearing drain port 114 are provided so as to open to the male rotor chamber S1. Preferably, the additional oil supply port 113 and the bearing drain port 114 are provided so as to open to a discharge-side space of the male rotor chamber S1 directly below the rotation axis of the male rotor 151.

In this way, of the main body oil supply port 112, the additional oil supply port 113, and the bearing drain port 114, only the main body oil supply port 112 may be provided on the female rotor chamber S2 side.

While the present invention has been described with reference to the specific embodiments, the present invention is not limited to the embodiments described above, and can be variously modified within the scope of the present invention.

For example, the number of the oil-

supply ports

112 and 113 and the number of the oil-discharge ports 114 may be any, and two or more ports may be provided. The position of the bearing oil drain port 114 in the rotation axis direction of the screw rotor 150 is not particularly limited, and can be disposed at any position. For example, the bearing drain port 114 may be provided on the suction side (left side in fig. 2) of the additional oil supply port 113 in the rotation axis direction of the screw rotor 150.

In addition, when one of the outer diameters of the male rotor and the female rotor is 100mm or less and the other is more than 100mm, the present invention is suitable for any of the embodiments 2 and 3. However, in such a case, it is preferable to give priority to embodiment 3 in which the additional oil supply port 113 is provided on the female rotor chamber S2 side. This is because the additional oil supply has a larger amount of oil per unit time than the bearing oil discharge, and therefore has a large influence on the energy efficiency (specific power) of the screw compressor 1.

Description of the reference numerals

1 screw compressor

5a to 5g flow path

10 compressor body

20 oil separating and recovering device

21 separator

22 oil tank

23. 24 temperature sensor

30 oil cooler

40 oil filter

50 solenoid valve

60 control device

61 load detection part

62 additional oil supply control part

100 compression part

110 rotor casing

111 closing wall

111a, 111b through hole

111c recess

112 main body oil supply port

113 additional fuel supply port

114 bearing oil drain

115 suction inlet

116 spout

120 bearing shell

121 closing wall

121a, 121b through hole

130 bearing shield

150 helical rotor

151 male rotor

151a, 151b shaft member

152 female rotor

152a, 152b shaft member

161-164 bearing

200 motor

S1 Male rotor Chamber

S2 female rotor chamber.

Claims

1. A screw compressor is characterized in that,

the disclosed device is provided with:

a male rotor;

a female rotor having more teeth than the male rotor and meshing with the male rotor;

a rotor housing having a suction port and a discharge port, and defining a male rotor chamber for accommodating the male rotor and a female rotor chamber for accommodating the female rotor;

a main body oil supply port provided in the rotor case so as to open to the discharge side space of the female rotor chamber;

an additional oil supply port provided in the rotor case closer to the discharge port side than the main oil supply port and opening to the discharge side space of the male rotor chamber or the discharge side space of the female rotor chamber;

an additional fuel supply adjusting mechanism for allowing or blocking the supply of fuel from the additional fuel supply port;

a load detection unit that detects a load acting on the screw compressor; and

and an additional fuel supply control unit that controls the additional fuel supply adjustment mechanism so that fuel supply from the additional fuel supply port is permitted when the load detected by the load detection unit is equal to or greater than a predetermined value, and so that fuel supply from the additional fuel supply port is blocked when the load detected by the load detection unit is less than the predetermined value.

2. The screw compressor according to claim 1,

further provided with:

a bearing for supporting the male rotor or the female rotor at a position closer to the discharge port of the rotor case;

a bearing oil drain line for transferring oil drained from the bearing; and

and a bearing oil drain port which is an outlet of the bearing oil drain line and is provided so as to open to the discharge-side space in the rotor case.

3. The screw compressor according to claim 1 or 2,

the additional oil supply port is provided so as to open to the male rotor chamber.

4. The screw compressor according to claim 1 or 2,

the additional oil supply port is provided so as to open to the female rotor chamber, and the main body oil supply port is not provided on the male rotor chamber side.

5. The screw compressor according to claim 2,

the additional oil supply port is provided so as to open to the female rotor chamber,

the bearing oil drain port is provided so as to open to the female rotor chamber,

the male rotor chamber side is not provided with a main body oil supply port and a bearing oil drain port.

6. A method of supplying oil to a screw compressor having:

a male rotor;

a main body oil supply port provided so as to open to the discharge side space of the female rotor chamber; and

an additional fuel supply port provided in a discharge side space on the discharge port side in the rotation axis direction of the female rotor with respect to the main fuel supply port;

the oil supply method of the screw compressor is characterized in that,

oil is supplied from the main body oil supply port to the female rotor chamber,

supplying oil from the additional oil supply port to the male rotor chamber or the female rotor chamber,

the load acting on the screw compressor is detected,

the additional fuel supply is controlled so that the fuel supply from the additional fuel supply port is permitted when the detected load is equal to or greater than a predetermined value, and the fuel supply from the additional fuel supply port is blocked when the detected load is not equal to the predetermined value.