Screw compressor
By guiding lubricating oil away from gear tooth grooves using grooves on the bearing retainers, the design reduces power loss and agitation in screw compressors, improving efficiency.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2026-03-19
AI Technical Summary
The agitation power of lubricating oil by gears in screw compressors increases, leading to power loss in the male and female rotors.
The design incorporates grooves on the outer end faces of the bearing retainers facing the gears, guiding lubricating oil away from the gear tooth grooves, reducing agitation and power loss.
The grooves effectively reduce the agitation power of lubricating oil, minimizing power loss and preventing uneven load distribution on the bearings, thus enhancing efficiency.
Smart Images
Figure JP2024032455_19032026_PF_FP_ABST
Abstract
Description
Screw compressor
[0001] The present invention relates to a screw compressor.
[0002] The screw compressor of Patent Document 1 includes a male rotor and a female rotor that are screw rotors, bearings that are arranged on one side and the other side in the axial direction of the male rotor and rotatably support the shaft portion of the male rotor, and bearings that are arranged outside the bearings on one side and the other side in the axial direction of the male rotor and fix the outer ring of the bearing. And a bearing retainer, bearings that are arranged on one side and the other side in the axial direction of the female rotor and rotatably support the shaft portion of the female rotor, and bearings that are arranged outside the bearings on one side and the other side in the axial direction of the female rotor and fix the outer ring of the bearing. retainer.
[0003] Further, the screw compressor of Patent Document 1 includes a drive gear (pinion gear) that is arranged outside the bearing retainer on one side in the axial direction of the male rotor and is attached to the shaft portion of the male rotor. The drive gear of the male rotor is meshed with a gear (bull gear) connected to the rotating shaft of the motor. Thereby, the rotational force of the motor is transmitted to the male rotor, and the male rotor rotates.
[0004] Further, the screw compressor of Patent Document 1 includes a synchronization gear that is arranged outside the bearing retainer on the other side in the axial direction of the male rotor and is attached to the shaft portion of the male rotor, and a synchronization gear that is arranged outside the bearing retainer on the other side in the axial direction of the female rotor. And a synchronization gear attached to the shaft portion of the female rotor. The synchronization gears of the male rotor and the female rotor are meshed with each other. Thereby, the rotational force of the male rotor is transmitted to the female rotor, and the female rotor rotates in synchronization with the male rotor.
[0005] Japanese Patent Laid-Open No. 06-288369
[0006] Although not described in Patent Document 1, lubricating oil is supplied to the bearings for the purpose of lubricating and cooling the bearings. A part of the lubricating oil supplied to the bearing flows out to the gear side through the through hole of the bearing retainer. At this time, if the lubricating oil flows into the tooth grooves of the gear, the power for the gear to agitate the lubricating oil increases, and the power loss of the male rotor or the female rotor increases.
[0007] This invention has been made in view of the above matters, and one of its objectives is to reduce the agitation power of lubricating oil by gears.
[0008] To solve the above problems, the configuration described in the claims is applied. The present invention includes a plurality of means for solving the above problems, but to give one example, a screw compressor comprising a screw rotor, a bearing that rotatably supports the shaft portion of the screw rotor, a bearing retainer that fixes the outer ring of the bearing, and a gear attached to the shaft portion of the screw rotor, wherein the gear, the bearing retainer, the bearing, and the teeth portion of the screw rotor are arranged in that order, the bearing retainer has a groove formed on its outer end face facing the gear for guiding lubricating oil that has leaked out from the bearing, and the groove extends from an inner end opening to the inner circumferential surface of the bearing retainer to an outer end opening to the outer circumferential surface of the bearing retainer or located radially outward from the gear.
[0009] According to the present invention, the agitation power of the lubricating oil by the gears can be reduced.
[0010] Furthermore, other issues, structures, and effects will be clarified in the following explanation.
[0011] This is an axial cross-sectional view showing the structure of a screw compressor in the first embodiment of the present invention. This is a partially enlarged cross-sectional view of part II in Figure 1, showing the structure of the bearing retainer in the first embodiment of the present invention. This is a radial cross-sectional view taken from arrow III-III in Figure 2, showing the structure of the bearing retainer in the first embodiment of the present invention. This is a partially enlarged cross-sectional view showing the structure of the bearing retainer in the second embodiment of the present invention. This is a radial cross-sectional view taken from arrow V-V in Figure 4, showing the structure of the bearing retainer in the second embodiment of the present invention. This is a radial cross-sectional view showing the structure of the bearing retainer in one modified example of the present invention. This is a radial cross-sectional view showing the structure of the bearing retainer in another modified example of the present invention.
[0012] A first embodiment of the present invention will be described with reference to Figures 1 to 3.
[0013] Figure 1 is an axial cross-sectional view showing the structure of the screw compressor in this embodiment. Figure 2 is a partially enlarged cross-sectional view of part II of Figure 1, showing the structure of the bearing retainer in this embodiment. Figure 3 is a radial cross-sectional view taken along arrow III-III in Figure 2, showing the structure of the bearing retainer in this embodiment. Although the oil supply passage for supplying lubricating oil to the bearing is not shown in Figure 1, the aforementioned oil supply passage is shown in Figure 2. Also, in Figure 3, for convenience, the outer diameter dimensions and position of the synchronous gear are shown by a dashed line.
[0014] The screw compressor of this embodiment comprises a male rotor 1 and a female rotor (not shown), which are screw rotors, and a casing 2 that houses the male rotor 1 and the female rotor. The male rotor 1 and the female rotor are arranged so that their axial directions (left-right direction in Figures 1 and 2) are horizontal and parallel to each other.
[0015] The male rotor 1 has a toothed portion 3 having a plurality of helical teeth, a shaft portion 4 connected to one axial side of the toothed portion 3 (left side in Figure 1), and a shaft portion 5A connected to the other axial side of the toothed portion 3 (right side in Figure 1). The shaft portion 4 on one side of the male rotor 1 is rotatably supported by a bearing 6, and the shaft portion 5A on the other side of the male rotor 1 is rotatably supported by a bearing 7. The bearing 6 is, for example, a roller bearing that supports radial loads, and the bearing 7 is, for example, a combination angular contact ball bearing that supports radial and thrust loads.
[0016] The female rotor has a toothed portion (not shown) having a plurality of helical teeth, a shaft portion (not shown) connected to one side of the toothed portion in the axial direction, and a shaft portion 5B (see Figure 3) connected to the other side of the toothed portion in the axial direction. The shaft portion on one side of the female rotor is rotatably supported by a bearing (not shown), and the shaft portion 5B on the other side of the female rotor is rotatably supported by a bearing (not shown).
[0017] On one axial side of the male rotor 1, an oil seal 8 is positioned inside the bearing 6 (right side in Figure 1), and a bearing retainer 9 is positioned outside the bearing 6 (left side in Figure 1). The oil seal 8 prevents lubricating oil from flowing into the working chamber, which will be described later. The bearing retainer 9 is attached to the casing 2 and applies an axial load (to the right in Figure 1) to the outer ring of the bearing 6, thereby fixing the outer ring of the bearing 6.
[0018] On one axial side of the female rotor, an oil seal (not shown) is positioned inside the bearing, and a bearing retainer (not shown) is positioned outside the bearing. The oil seal prevents lubricating oil from flowing into the working chamber, which will be described later. The bearing retainer is attached to the casing 2 and applies an axial load to the outer ring of the bearing, thereby fixing the outer ring of the bearing.
[0019] On one axial side of the male rotor 1, outside the bearing retainer 9 (left side in Figure 1), a drive gear 10 (e.g., a pinion gear) is positioned. The drive gear 10 is positioned by a spacer 11 interposed between it and the inner ring of the bearing 6, and is attached to the shaft portion 4 on one side of the male rotor 1. The drive gear 10 is meshed with a gear 13 (e.g., a bull gear) connected to the rotating shaft of the motor 12. As a result, the rotational force of the motor 12 is transmitted to the male rotor 1, causing the male rotor 1 to rotate. The drive gear 10, bearing retainer 9, bearing 6, and the teeth portion 3 of the male rotor 1 are arranged in that order in the axial direction of the male rotor 1.
[0020] On the other axial side of the male rotor 1, an oil seal 14 is positioned inside the bearing 7 (left side in Figure 1), and a bearing retainer 15A is positioned outside the bearing 7 (right side in Figure 1). The oil seal 14 prevents lubricating oil from flowing into the working chamber, which will be described later. The bearing retainer 15A is attached to the casing 2 and applies an axial load (leftward in Figure 1) to the outer ring of the bearing 7, thereby fixing the outer ring of the bearing 7.
[0021] On the other axial side of the female rotor, an oil seal (not shown) is positioned inside the bearing, and a bearing retainer 15B (see Figure 3) is positioned outside the bearing. The oil seal prevents lubricating oil from flowing into the working chamber, which will be described later. The bearing retainer 15B is attached to the casing 2 and applies an axial load to the outer ring of the bearing, thereby fixing the outer ring of the bearing.
[0022] On the other axial side of the male rotor 1, a synchronous gear 16A is positioned outside the bearing retainer 15A (right side in Figure 1). The synchronous gear 16A is positioned by a spacer 17A interposed between it and the inner ring of the bearing 7, and is attached to the shaft portion 5A on the other side of the male rotor 1. The synchronous gear 16A, bearing retainer 15A, bearing 7, and the teeth 3 of the male rotor 1 are arranged in that order in the axial direction of the male rotor 1. On the other axial side of the female rotor, a synchronous gear 16B (see Figure 3) is positioned outside the bearing retainer 15B. The synchronous gear 16B is positioned by a spacer 17B (see Figure 3) interposed between it and the inner ring of the bearing, and is attached to the shaft portion 5B on the other side of the female rotor. The synchronous gear 16B, bearing retainer 15B, bearing, and the teeth of the female rotor are arranged in that order in the axial direction of the female rotor.
[0023] The synchronous gear 16A of the male rotor 1 and the synchronous gear 16B of the female rotor mesh with each other. As a result, the rotational force of the male rotor 1 is transmitted to the female rotor, and the female rotor rotates in sync with the male rotor. Therefore, the teeth 3 of the male rotor 1 and the teeth of the female rotor mesh without contact, and the male rotor 1 and the female rotor rotate.
[0024] Multiple working chambers are formed in the teeth 3 of the male rotor 1 and the teeth of the female rotor. Each working chamber moves in the axial direction of the male rotor 1 and the female rotor (to the right in Figure 1) as the male rotor 1 and the female rotor rotate, and its volume also changes. This allows for the sequential execution of an intake stroke in which gas (e.g., air) is drawn in through the intake passage 18, a compression stroke in which the gas is compressed, and a discharge stroke in which compressed gas (e.g., compressed air) is discharged through the discharge passage 19.
[0025] The bearing 6, located on one axial side of the male rotor 1, is supplied with lubricating oil, for example, through an oil supply path (not shown) formed in the casing 2. A portion of the lubricating oil supplied to the bearing 6 flows out to the drive gear 10 side (left side in Figure 1) through the through hole in the bearing retainer 9 (in other words, the gap between the bearing retainer 9 and the spacer 11). The bearing, located on one axial side of the female rotor, is supplied with lubricating oil, for example, through an oil supply path (not shown) formed in the casing 2. A portion of the lubricating oil supplied to the bearing flows out through the through hole in the bearing retainer.
[0026] The bearing 7, located on the other axial side of the male rotor 1, is supplied with lubricating oil, for example, through an oil supply path 20 formed in the casing 2 and the bearing retainer 15A. A portion of the lubricating oil supplied to the bearing 7 flows out to the synchronous gear 16A side (right side in Figures 1 and 2) through the through hole 21A of the bearing retainer 15A (in other words, the gap between the bearing retainer 15A and the spacer 17A). The bearing located on the other axial side of the female rotor is supplied with lubricating oil, for example, through an oil supply path (not shown) formed in the casing 2 and the bearing retainer 15B. A portion of the lubricating oil supplied to the bearing flows out to the synchronous gear 16B side through the through hole 21B of the bearing retainer 15B (in other words, the gap between the bearing retainer 15B and the spacer 17B). Here, when the lubricating oil flows into the tooth grooves of the synchronous gears 16A and 16B, the power with which the synchronous gears 16A and 16B agitate the lubricating oil increases.
[0027] Therefore, the bearing retainer 15A in this embodiment has a groove 22A formed on its outer end face facing the synchronous gear 16A. The groove 22A extends from an inner end that opens onto the inner circumferential surface of the bearing retainer 15A to an outer end that does not open onto the outer circumferential surface of the bearing retainer 15A but is located radially outward from the synchronous gear 16A. The groove 22A also extends in the vertical direction (downward in Figures 1 to 3). As a result, the inner end of the groove 22A is located above the outer end in the vertical direction. Lubricating oil flowing out from the bearing 7 located on the other axial side of the male rotor 1 is guided by the groove 22A of the bearing retainer 15A, thereby suppressing its flow into the tooth grooves of the synchronous gear 16A and reducing the stirring power of the lubricating oil by the synchronous gear 16A. Therefore, power loss of the male rotor 1 can be reduced.
[0028] In this embodiment, the inner end of the groove 22A is located below the shaft portion 5A of the male rotor 1 in the vertical direction (see Figures 2 and 3). Therefore, compared to the case where the inner end of the groove 22A is located above the shaft portion 5A of the male rotor 1 in the vertical direction, the accumulation of lubricating oil in the through hole 21A of the bearing retainer 15A is suppressed, and the stirring power of the lubricating oil by the shaft portion 5A of the male rotor 1 can be suppressed. Thus, the power loss of the male rotor 1 can be suppressed. Furthermore, the inner end of the groove 22A is located below the center of the lowest rolling element of the bearing 7 in the vertical direction (see Figure 2). Therefore, compared to the case where the inner end of the groove 22A is located above the center of the lowest rolling element of the bearing 7 in the vertical direction, the accumulation of lubricating oil in the through hole 21A of the bearing retainer 15A is suppressed, and the stirring power of the lubricating oil by the bearing 7 can also be suppressed. Furthermore, if a groove is formed on the inner end face of the bearing retainer 15A, the load distribution applied to the bearing 7 will become uneven, which may cause problems such as vibration of the bearing 7. In this embodiment, a groove is formed on the outer end face of the bearing retainer 15A, so the aforementioned problems can be avoided.
[0029] The bearing retainer 15B in this embodiment has a groove 22B formed on its outer end face facing the synchronous gear 16B. The groove 22B extends from an inner end that opens onto the inner circumferential surface of the bearing retainer 15B to an outer end that does not open onto the outer circumferential surface of the bearing retainer 15B but is located radially outward from the synchronous gear 16B. The groove 22B also extends in the vertical direction (downward in Figure 3). Therefore, the inner end of the groove 22B is located above the outer end in the vertical direction. Lubricating oil flowing out from the bearing located on the other axial side of the female rotor is guided by the groove 22B of the bearing retainer 15B, thereby suppressing its flow into the tooth grooves of the synchronous gear 16B and reducing the agitation power of the lubricating oil by the synchronous gear 16B. Consequently, power loss of the female rotor can be reduced.
[0030] In this embodiment, the inner end of the groove 22B is located below the shaft portion 5B of the female rotor in the vertical direction (see Figure 3). Therefore, compared to the case where the inner end of the groove 22B is located above the shaft portion 5B of the female rotor in the vertical direction, the accumulation of lubricating oil in the through hole 21B of the bearing retainer 15B is suppressed, and the stirring power of the lubricating oil by the shaft portion 5B of the female rotor can be suppressed. Thus, the power loss of the female rotor can be suppressed. Furthermore, the inner end of the groove 22B is located below the center of the lowest rolling element of the bearing in the vertical direction. Therefore, compared to the case where the inner end of the groove 22B is located above the center of the lowest rolling element of the bearing in the vertical direction, the accumulation of lubricating oil in the through hole 21B of the bearing retainer 15B can be suppressed, and the stirring power of the lubricating oil by the bearing can also be suppressed. Note that if a groove is formed on the inner end face of the bearing retainer 15B, the distribution of the load applied to the bearing will become uneven, which may cause problems such as bearing vibration. In this embodiment, a groove is formed on the outer end face of the bearing retainer 15B, thus avoiding the aforementioned problems.
[0031] A second embodiment of the present invention will be described with reference to Figures 4 and 5. In this embodiment, parts equivalent to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.
[0032] Figure 4 is a partially enlarged cross-sectional view showing the structure of the bearing retainer in this embodiment. Figure 5 is a radial cross-sectional view taken along the line V-V in Figure 4, showing the structure of the bearing retainer in this embodiment.
[0033] In this embodiment, the groove 22A of the bearing retainer 15A extends from the inner end opening to the inner circumferential surface of the bearing retainer 15A to the outer end opening to the outer circumferential surface of the bearing retainer 15A (preferably located radially outward from the synchronous gear 16A). Lubricating oil flowing out from the bearing 7 located on the other axial side of the male rotor 1 is guided by the groove 22A of the bearing retainer 15A, thereby suppressing its flow into the tooth grooves of the synchronous gear 16A and reducing the stirring power of the lubricating oil by the synchronous gear 16A. Therefore, power loss of the male rotor 1 can be reduced.
[0034] In this embodiment, the groove 22B of the bearing retainer 15B extends from an inner end opening on the inner circumferential surface of the bearing retainer 15B to an outer end opening on the outer circumferential surface of the bearing retainer 15B (preferably located radially outward from the synchronous gear 16B). Lubricating oil flowing out from the bearing located on the other axial side of the female rotor is guided by the groove 22B of the bearing retainer 15B, thereby suppressing its flow into the tooth grooves of the synchronous gear 16B and reducing the stirring power of the lubricating oil by the synchronous gear 16B. Therefore, power loss of the female rotor can be reduced.
[0035] In the first and second embodiments, the groove 22A of the bearing retainer 15A or the groove 22B of the bearing retainer 15B was described as extending in the vertical direction, but it is not limited to this. For example, as shown in the modified example in Figure 6, the groove 22A of the bearing retainer 15A may be located on the side away from the bearing retainer 15B (left side in Figure 6) and extend in the horizontal direction (left direction in Figure 6). That is, the inner end of the groove 22A may be at the same height as the outer end in the vertical direction. It is desirable that at least a part of the inner end of the groove 22A is located below the shaft portion 5A of the male rotor 1 in the vertical direction, and furthermore, below the center of the lowest rolling element of the bearing 7 in the vertical direction. The groove 22B of the bearing retainer 15B may be located on the side away from the bearing retainer 15A (right side in Figure 6) and extend in the horizontal direction (right direction in Figure 6). That is, the inner end of the groove 22B may be at the same height as the outer end in the vertical direction. It is desirable that at least a portion of the inner end of the groove 22B is located below the shaft portion 5B of the female rotor in the vertical direction, and furthermore, below the center of the lowest rolling element of the bearing in the vertical direction.
[0036] For example, as shown in the modified example in Figure 7, the groove 22A of the bearing retainer 15A may be located on the side approaching the bearing retainer 15B (right side in Figure 7) and extend in an oblique direction between the vertical and horizontal directions. The inner end of the groove 22A is located above the outer end in the vertical direction. At least a portion of the inner end of the groove 22A is located below the shaft portion 5A of the male rotor 1 in the vertical direction, and it is also desirable that it is located below the center of the lowest rolling element of the bearing 7 in the vertical direction. The groove 22B of the bearing retainer 15B may be located on the side approaching the bearing retainer 15A (left side in Figure 7) and extend in an oblique direction between the vertical and horizontal directions. The inner end of the groove 22B is located above the outer end in the vertical direction. At least a portion of the inner end of the groove 22B is located below the shaft portion 5B of the female rotor in the vertical direction, and it is also desirable that it is located below the center of the lowest rolling element of the bearing in the vertical direction. In this modified example, lubricating oil flowing out from the bearing 7 located on the other axial side of the male rotor 1 is guided by the groove 22A of the bearing retainer 15A, and lubricating oil flowing out from the bearing located on the other axial side of the female rotor is guided by the groove 22B of the bearing retainer 15B, and these merge and flow through the passage between the bearing retainers 15A and 15A. Therefore, the same effects as in the above embodiment can be obtained.
[0037] In the first and second embodiments and their modifications, the features of the present invention were described using the application of the features of the present invention to the bearing retainers 15A and 15B as an example, but the invention is not limited to this, and the features of the present invention may also be applied to the bearing retainer 9. That is, the bearing retainer 9 may have a groove formed on its outer end face facing the drive gear 10. This groove extends from an inner end opening on the inner circumferential surface of the bearing retainer 9 to an outer end opening on the outer circumferential surface of the bearing retainer 9 or located radially outward from the drive gear 10. By guiding the lubricating oil flowing out from the bearing 6 through the groove of the bearing retainer 9, it is possible to suppress its flow into the tooth grooves of the drive gear 10 and reduce the agitation power of the lubricating oil by the drive gear 10. Therefore, the power loss of the male rotor can be reduced.
[0038] 1...Male rotor, 4...Shaft section, 5A...Shaft section, 6...Bearing, 7...Bearing, 9...Bearing retainer, 10...Drive gear, 15A, 15B...Bearing retainers, 16A, 16B...Synchronizing gear, 22A, 22B...Groove
Claims
1. A screw compressor comprising a screw rotor, a bearing that rotatably supports the shaft portion of the screw rotor, a bearing retainer that fixes the outer ring of the bearing, and a gear attached to the shaft portion of the screw rotor, wherein the gear, the bearing retainer, the bearing, and the teeth of the screw rotor are arranged in that order, wherein the bearing retainer has a groove formed on its outer end face facing the gear for guiding lubricating oil flowing out from the bearing, and the groove extends from an inner end opening to the inner circumferential surface of the bearing retainer to an outer end opening to the outer circumferential surface of the bearing retainer or located radially outward from the gear.
2. A screw compressor according to claim 1, wherein the inner end of the groove is located at the same height as or above the outer end in the vertical direction.
3. A screw compressor according to claim 2, wherein at least a portion of the inner end of the groove is located below the shaft in the vertical direction.
4. A screw compressor according to claim 3, wherein at least a portion of the inner end of the groove is located below the center of the lowest rolling element of the bearing in the vertical direction.
Citation Information
Patent Citations
Screw fluid machine and multistage screw fluid machine
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