JP2014077475A - Bearing structure and water injection type air compression device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively manufacture a bearing structure capable of being easily machined and excellent in abrasion resistance.SOLUTION: A bearing structure 120 includes a rotation-side bearing surface 122a which is provided in rotating shafts (a main screw rotor 116a and a sub-screw rotor 116b) and which is made of carbon impregnated with a resin, and a bearing member (a thrust bearing 126) having a stationary side bearing surface 126a which is made of stainless steel and which bears a load acting on the rotating shafts by sliding movement generated between it and the rotation-side bearing surface 122a.

Description

  The present invention relates to a bearing structure lubricated with a liquid, and a water injection type air compressor using the same.

  A water-lubricated bearing using water as a lubricating liquid is used for screw compressors, submersible pumps, and the like. Conventionally, the water-lubricated bearing is made of, for example, ceramic, carbon, PEEK (polyether ether ketone) resin, or phenol resin.

  Among such water-lubricated bearings, in a thrust bearing that receives a thrust load of a rotating shaft, a technique for improving the dynamic pressure effect by forming irregularities on the sliding surface is disclosed (for example, Patent Document 1).

  In addition, as a thrust bearing structure, for example, in Patent Document 2, any one of a rotation-side member and a fixed-side member is a metal base material in which a titanium nitride film is formed on a slip surface, and the other is a slip surface. It describes a configuration that is a metal substrate having a DLC (diamond-like carbon) film formed on the surface.

Japanese Patent Laid-Open No. 11-351242 Japanese Patent No. 3963994

  However, it is difficult to subject the water-lubricated bearing formed of ceramic or carbon to the unevenness described in Patent Document 1. In addition, a water-lubricated bearing formed of ceramic or carbon does not have sufficient wear resistance and does not fit well with the counterpart member.

  In addition, the water-lubricated bearing formed of resin is easy to be subjected to the concavo-convex processing described in Patent Document 1, but has a problem that it is easily deformed because of its low strength and low Young's modulus. In addition, the resin may swell with water and change its shape.

  Furthermore, although the water-lubricated bearing described in Patent Document 2 has excellent wear resistance, titanium nitride and DLC can be formed without using a large-scale apparatus such as a CVD (chemical vapor deposition) apparatus or a sputtering apparatus. There is a problem that the manufacturing cost of the bearing increases.

  Therefore, in view of such problems, the present invention provides a bearing structure that can be easily processed, has excellent wear resistance, and can be manufactured at low cost, and a water-injection type air compressor using the same. It is intended to provide.

  In order to solve the above-described problems, a bearing structure of the present invention includes a rotation-side bearing surface made of carbon impregnated with a resin provided on a rotation shaft, and a rotation-side bearing surface made of stainless steel. And a bearing member having a fixed-side bearing surface that receives a load acting on the rotating shaft by a sliding motion generated therebetween.

  The fixed-side bearing surface may receive a thrust load acting on the rotating shaft.

  A hydrophilic solvent is used as the lubricating liquid of the bearing structure, and the resin may be a resin having a hydroxyl group.

  In order to solve the above problems, a water-injection type air compressor according to the present invention includes a housing, a plurality of screw rotors provided in the housing, and screwed together so as to compress air by being integrally rotated. A thrust collar provided on the screw rotor and having a rotation side bearing surface made of carbon impregnated with resin, and fixed to the housing, made of stainless steel, and generated between the rotation side bearing surface And a thrust bearing having a fixed bearing surface that receives a thrust load acting on the screw rotor by a sliding motion.

  According to the present invention, a bearing structure can be manufactured at low cost, which can be easily processed and has excellent wear resistance.

It is a figure for demonstrating a water injection type air compression system. It is a figure for demonstrating the structure of a water injection type air compressor.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Water injection air compression system 100)
FIG. 1 is a view for explaining a water injection type air compression system 100. In FIG. 1, the flow of air and water is indicated by solid arrows, and the flow of signals is indicated by broken arrows.

  The water injection type air compression device 110 constituting the water injection type air compression system 100 is a device that compresses air by rotating two screw rotors by rotating the two screw rotors by a motor 130 with a fan. Yes, water is used as a lubricant.

  First, the flow of air in the water injection type air compression system 100 will be described. As shown in FIG. 1, the water injection type air compression device 110 compresses the introduced air. The compressed air (hereinafter simply referred to as compressed air) is introduced into the water tank 140 together with water via the compressed air line 200a, and after the water is separated in the water tank 140, the compressed air line 200b. Then, water is further removed by the dehumidifier 160 and supplied to the supply destination.

  Next, the flow of water will be described. The water introduced into the water-injection type air compressor 110 from the water supply source via the water line 200c functions as a lubricating liquid, and then, together with the compressed air, passes through the compressed air line 200a. And introduced into the water tank 140. Moreover, the water introduced from the water supply source via the water line 200d is stored in the water tank 140, and the water introduced from the water jet type air compressor 110 joins the stored water. . Then, the water stored in the water tank 140 is introduced into the cooler 170 through the water line 200e, and then cooled in the cooler 170, and then supplied to the water injection type air compressor 110 through the water line 200f and the water filter 202a. It will be introduced again. That is, water circulates through the water jet type air compressor 110, the water tank 140, and the cooler 170.

  Subsequently, specific configurations of the motor 130 with a fan, the water tank 140, the control unit 150, the dehumidifier 160, the cooler 170, and the water injection type air compression device 110 that constitute the water injection type air compression system 100 will be described in this order. To do.

  The fan motor 130 includes a fan 132, a motor-side pulley 134, and a motor (drive unit) 136. The fan 132 is rotationally driven by the motor 136 and blows air to the cooler 170. The motor side pulley 134 is rotationally driven by the motor 136 together with the fan 132. An endless belt 138 is stretched around the motor-side pulley 134, and the belt 138 is further stretched around the compression-side pulley 112 of the water jet type air compressor 110.

  Therefore, when the motor-side pulley 134 is rotationally driven by the motor 136, the compression-side pulley 112 rotates via the belt 138, and the air is compressed in the water jet type air compressor 110. The air compressed in the water jet type air compressor 110 is introduced into the gas-liquid separator 142 of the water tank 140 through the compressed air line 200a together with water that functions as a lubricating liquid of the water jet type air compressor 110.

  The water tank 140 is a tank for storing water, and a gas-liquid separation unit 142 is provided in the upper space. The gas-liquid separation unit 142 gas-liquid separates the mixture of compressed air and water introduced from the water jet type air compressor 110 via the compressed air line 200a, that is, separates water from the compressed air. The water separated by the gas-liquid separation unit 142 is merged with the water stored in the water tank 140 (lower part of the water tank 140).

  As described above, since compressed air (for example, about 0.7 MPa) is introduced into the water tank 140, the inside of the water tank 140 is always pressurized. Therefore, the water stored in the water tank 140 is pumped to the cooler 170 through the water line 200e.

  Further, the water tank 140 is provided with a water level sensor 144 that detects the water level of the water stored in the water tank 140. A water level signal indicating the water level detected by the water level sensor 144 is transmitted to the control unit 150.

  The control unit 150 manages and controls the entire water injection type air compression system 100 by a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing a program, a RAM as a work area, and the like. In the present embodiment, the control unit 150 transmits the pressure signal indicating the measured pressure transmitted from the pressure measurement unit 210 that measures the pressure of water introduced from the water supply source, and the water level signal transmitted from the water level sensor 144. The electromagnetic valves 220a and 220b provided in the water line 200c, the electromagnetic valve 220c provided in the water line 200d, and the electromagnetic valve 220d provided in the drain line 200g connected to the water tank 140 are controlled.

  More specifically, the controller 150 is based on the pressure signal so that an amount of water that is sufficient for lubricating the water-injection air compressor 110 and that does not interfere with air compression is introduced. The opening degree of the electromagnetic valves 220a and 220b is adjusted. Further, the control unit 150 maintains the water level in the water tank 140 at a predetermined height (for example, an intermediate position of the water tank 140), based on the pressure signal and the water level signal, the electromagnetic valves 220c and 220d. Adjust the opening.

  Note that a check valve 230a is provided between the electromagnetic valve 220c and the water tank 140 in the water line 200d to prevent the backflow of water from the water tank 140 to the water line 200d. In addition, a check valve 230b is provided between the electromagnetic valve 220a and the water injection type air compressor 110 in the water line 200c to prevent the back flow of water from the water injection type air compressor 110 to the water line 200c. It is preventing.

  The dehumidifier 160 is connected to the water tank 140 via the compressed air line 200b, and cools the compressed air introduced from the water tank 140 to a temperature equal to or lower than the saturation temperature of water, so that water ( Gas) to separate water from the compressed air. Then, the compressed air from which water has been removed by the dehumidifier 160 is supplied to the supply destination, and the separated water is supplied to the water injection type air compressor 110 together with the compressed air via the drain trap 202b and the water line 200h. be introduced. The compressed air line 200b is provided with a check valve 230c to prevent the backflow of compressed air from the dehumidifier 160 to the water tank 140.

  The cooler 170 cools the water supplied from the water tank 140 through the water line 200 e to about 10 ° C. by the air blow from the fan 132 of the fan-equipped motor 130. The water cooled by the cooler 170 is introduced into the water jet type air compressor 110 through the water line 200f.

  FIG. 2 is a diagram for explaining the configuration of the water-injection type air compressor 110. As shown in FIG. 2, the water injection type air compressor 110 is a twin screw compressor, and has a main screw rotor 116a (rotary shaft) and a sub screw rotor 116b (rotary shaft) in a housing 114. ing. A compression pulley 112 is connected to the main screw rotor 116a, and is rotated by the motor 136 of the fan motor 130 via the belt 138 as described above.

  A sub screw rotor 116b is screwed to the main screw rotor 116a. When the main screw rotor 116a rotates, the sub screw rotor 116b rotates integrally. The sub screw rotor 116b rotates in the direction opposite to the rotation direction of the main screw rotor 116a.

  When air is introduced from an air inlet (not shown), the air is introduced into the region R, and the air introduced into the region R is compressed between the main screw rotor 116a and the sub screw rotor 116b, and the casing 114 It is sent out from the discharge port 114a formed in the above. The discharge port 114a is connected to the compressed air line 200a, and the compressed air sent from the discharge port 114a is introduced into the water tank 140.

  Further, the casing 114 is provided with a compressed air introduction port 114b connected to the water line 220h, and the compressed air is introduced into the casing 114 from the compressed air introduction port 114b. As a result, contamination (contamination) can be prevented from entering the casing 114 from the outside.

  The housing 114 is provided with a plurality of water introduction ports 114c connected to the water lines 200c and 200f, and water is introduced into the housing 114 from the water introduction ports 114c. The introduced water is a sliding surface between the journal bearing 118 and the main screw rotor 116a, which will be described later, a sliding surface between the journal bearing 118 and the sub screw rotor 116b, and a rotational bearing surface 122a and a thrust bearing of the thrust collar 122 which will be described later. 126 (bearing member) flows into the gap between the fixed side bearing surface 126a and functions as a lubricating liquid. The introduced water has a function of cooling the compressed air and plays a role of improving the compression efficiency.

  Two journal bearings 118 are inserted through the outer peripheral surfaces of the main screw rotor 116a and the sub screw rotor 116b, respectively. A radial load is applied to the rotor 116b.

  The water injection type air compressor 110 is provided with a bearing structure 120. The bearing structure 120 includes a thrust collar 122 provided in each of the main screw rotor 116a and the sub screw rotor 116b, and two thrust bearings 126 provided in the housing 114, and each of the two thrust bearings 126 is provided. The thrust load of the main screw rotor 116a and the thrust load of the sub screw rotor 116b are received. Since the bearing structure 120 that receives the thrust load of the main screw rotor 116a and the bearing structure 120 that receives the thrust load of the sub screw rotor 116b have substantially the same function, in this embodiment, the thrust load of the main screw rotor 116a. The bearing structure 120 that receives the thrust is described, and the description of the bearing structure 120 that receives the thrust load of the sub-screw rotor 116b is omitted.

  The thrust collar 122 is fixed to the main screw rotor 116a.

  The thrust bearing 126 is an annular member having an insertion hole, and is fixed to the housing 114, and the main screw rotor 116a is inserted through the insertion hole. The thrust bearing 126 has a fixed bearing surface 126a that receives a thrust load acting on the main screw rotor 116a by a sliding motion generated between the thrust bearing 122 and the rotation bearing surface 122a.

  Therefore, when the main screw rotor 116a rotates, the thrust collar 122 and the thrust bearing 126 rotate relative to each other, and the fixed-side bearing surface 126a is caused by the sliding motion generated between the fixed-side bearing surface 126a and the rotating-side bearing surface 122a. However, the thrust load in the right direction in FIG. 2 acting on the main screw rotor 116a is received.

  A plate member 128 is fixed to the rear end portion of the main screw rotor 116a and the rear end portion of the sub screw rotor 116b. The outer diameter of the plate member 128 is larger than the outer diameter of the rear end portion of the main screw rotor 116 a and the outer diameter of the rear end portion of the sub screw rotor 116 b, and the bearing surface 128 a of the plate member 128 is the thrust bearing surface of the journal bearing 118. Opposed to 118a. Further, the bearing surface 128a of the plate member 128 acts on the main screw rotor 116a and the sub screw rotor 116b by the sliding motion generated between the bearing surface 128a of the plate member 128 and the thrust bearing surface 118a of the journal bearing 118. 2 It is configured to receive a thrust load in the left direction.

  In the present embodiment, the fixed-side bearing surface 126a in the thrust bearing 126 is made of stainless steel, for example, SUS630, SUS431, or a titanium-based alloy. By configuring the fixed-side bearing surface 126a with stainless steel, the fixed-side bearing surface 126a can be easily processed. For example, the fixed-side bearing surface 126a can be burnished, or the fixed-side bearing surface 126a can be processed into a tapered land shape. By doing so, it becomes possible to efficiently distribute water (lubricating liquid) to the fixed-side bearing surface 126a.

  Further, by configuring the fixed-side bearing surface 126a with stainless steel, corrosion resistance and wear resistance can be improved.

  In the present embodiment, the rotation-side bearing surface 122a of the thrust collar 122 is made of carbon impregnated with resin. Thereby, compared with the case where the rotation side bearing surface 122a is comprised with a carbon single-piece | unit, abrasion resistance can be improved, and compatibility with the other party member (fixed side bearing surface 126a, ie, stainless steel) is improved. It becomes possible to improve. In addition, the wear resistance can be improved as compared with the case where the rotation-side bearing surface 122a is made of a single resin, and the shape change due to water can be almost eliminated.

  Here, carbon is a fired body of graphite. The resin is a resin having a hydroxyl group, such as a furan resin or a phenol resin. In this way, by using a resin having a hydroxyl group, that is, a resin having a high affinity for water (lubricating liquid), the compatibility of the rotation-side bearing surface 122a and water can be improved. Water can be evenly distributed between the bearing surface 122a and the fixed-side bearing surface 126a.

  Further, since the stainless steel constituting the fixed side bearing surface 126a and the carbon and resin constituting the rotation side bearing surface 122a are less expensive than the case of forming a conventional titanium nitride or DLC film, the cost is low. Thus, the bearing structure 120 can be manufactured.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, the bearing structure 120 including the thrust bearing 126 that receives the thrust load of the rotating shaft (the main screw rotor 116a and the sub screw rotor 116b) has been described as an example of the bearing structure. A bearing structure that receives a radial load may be used as long as the stationary bearing surface is made of stainless steel and the rotating bearing surface is made of carbon impregnated with resin. For example, in a journal bearing structure that has a sleeve shape and includes a rotation-side bearing surface through which the rotation shaft is inserted and fixed to the rotation shaft, and a bearing member having a fixed-side bearing surface that rotates relative to the rotation-side bearing surface. The present invention can also be applied.

  In the above-described embodiment, water has been described as an example of the lubricating liquid. However, the lubricating liquid is not limited to water, and any low-viscosity hydrophilic solvent such as methanol or ethanol may be used. Further, the lubricating liquid may be an oleophilic solvent. In this case, a bearing structure having a rotation-side bearing surface made of carbon impregnated with a resin having an oleophilic functional group may be used.

  In the above-described embodiment, the bearing structure 120 used in the water-injection type air compressor 110 has been described. However, the present invention is not limited to the water-injection type air compressor 110, and is not limited to the bearing structure of other devices having a rotating shaft. The invention can be applied.

  In the above-described embodiment, the water-injection type air compressor 110 including two screw rotors (main screw rotor 116a and sub screw rotor 116b) has been described. However, the number of screw rotors may be three or more. .

  INDUSTRIAL APPLICABILITY The present invention can be used for a bearing structure that is lubricated with a liquid and a water jet type air compressor using the same.

DESCRIPTION OF SYMBOLS 110 ... Water-injection type air compressor 114 ... Case 116a ... Main screw rotor (rotary shaft, screw rotor)
116b ... Sub screw rotor (rotary shaft, screw rotor)
DESCRIPTION OF SYMBOLS 120 ... Bearing structure 122 ... Thrust collar 122a ... Rotation side bearing surface 126 ... Thrust bearing (bearing member)
126a ... fixed side bearing surface

Claims (4)

A rotation-side bearing surface made of carbon impregnated with resin and provided on the rotation shaft;
A bearing member having a fixed-side bearing surface that is made of stainless steel and receives a load acting on the rotating shaft by a sliding motion generated between the rotating-side bearing surface;
A bearing structure characterized by comprising:   The bearing structure according to claim 1, wherein the fixed-side bearing surface receives a thrust load acting on the rotating shaft. A hydrophilic solvent is used as a lubricant for the bearing structure,
The bearing structure according to claim 1, wherein the resin is a resin having a hydroxyl group. A housing,
A plurality of screw rotors that are provided in the housing and are screwed to each other to compress air by rotating together;
A thrust collar provided on the screw rotor and having a rotation-side bearing surface made of carbon impregnated with resin;
A thrust bearing having a fixed bearing surface that is fixed to the housing and is made of stainless steel and receives a thrust load acting on the screw rotor by a sliding motion generated between the rotating bearing surface and the bearing;
A water-injection type air compressor.

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