JP2006002596A - Bearing device and pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device capable of successfully maintaining, for a long term, lubrication of a rolling bearing mounted on an inner rear position of a bearing hole which a rotational shaft is inserted into and supported by, and a vacuum pump equipped with the bearing device. <P>SOLUTION: The rotational shaft 20 is inserted into and supported by the bearing hole 19 of a bearing body 15 assembled and fixed to a rear housing 14, in the state where one end 20a of the rotational shaft 20 is projected into inside of an oil reservoir chamber 23. The predetermined rolling bearing 35 for supporting radial load of the rotational shaft 20 is mounted on the inner rear position inside the bearing hole 19. A helical groove 37 exerting pump action is formed on the outer peripheral face of the rotational shaft 20, and a communication passage 38 for communicating the predetermined rolling bearing 35 inside the bearing hole 19 with the oil reservoir chamber 23 of a gear housing 22 is formed inside the bearing body 15. Lubrication of the predetermined rolling bearing 35 is performed via a circulation path of lubricating oil 24 comprising the helical groove 37 and the communication passage 38. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pump device used in, for example, a semiconductor manufacturing process, and a bearing device suitable for application to the pump device.

Generally, in a semiconductor manufacturing process, a vacuum pump which is a kind of pump device is used to create a vacuum environment. That is, in the semiconductor manufacturing process, in order to perform various processes on the wafer in a vacuum environment, an inert gas such as F ₂ gas that is a fluid is supplied into the container in which the wafer is stored, while the gas is put into the container. The remaining impurities (O ₂ , CO _2, etc.) are sucked with a vacuum pump to create a clean vacuum environment in the container. As such a vacuum pump, various vacuum pumps such as a screw-type vacuum pump described in Patent Document 1 have been proposed in addition to a roots-type vacuum pump.

The screw type vacuum pump of Patent Document 1 is configured such that a pair of screw rotors meshing in a spiral manner functions as a fluid (gas) transfer body, and each of the screw rotors is a stationary bearing body protruding into the pump chamber. A cylindrical portion (tubular portion) is supported in a cantilever shape. In addition, a rotating shaft that rotates based on the driving force of the driving source is inserted into the support hole that passes through the stationary bearing body (and its cylindrical portion), and the screw rotor rotates integrally with the rotating shaft. So that they are connected. In addition, rolling bearings for rotatably supporting the rotating shaft are attached to a plurality of locations such as the inner back position in the support hole of the stationary bearing body, and these rolling bearings and the stationary bearing body A bearing device is configured. When the screw rotor is rotated based on the rotation of the rotating shaft, the inert gas is sucked into the pump chamber from the outside and is transferred to the discharge side while being compressed by the screw rotor in the pump chamber. It is designed to be discharged from the room to the outside.
Japanese National Patent Publication No. 11-508343 (Specification, page 7, line 8 to line 17, FIG. 1)

  By the way, the rolling bearing of the bearing device in the vacuum pump needs to be sufficiently lubricated in order to maintain the bearing function. Therefore, when the mounting position of the rolling bearing in the support hole is a position aspect facing the gear chamber (oil reservoir chamber) in which lubricating oil is stored in the vacuum pump, the gear (or the splasher) provided in the gear chamber is When the rotating shaft rotates, the lubricating oil in the gear chamber is spun up, and the rolling bearing is lubricated by the splashing of the oil. However, when the rolling bearing is mounted in a position where the spray lubrication from the gear chamber does not reach in the support hole, that is, the inner position in the support hole, the rolling bearing is lubricated with such a spray lubrication. I could n’t.

  Therefore, in the vacuum pump of Patent Document 1, for a rolling bearing attached in the inner position in the support hole, such as a rolling bearing attached in the support hole on the tip side of the cylindrical portion, the vacuum pump A lubricant such as grease is sealed in the inner position of the support hole, which is the mounting position of the rolling bearing when assembled, and the rolling bearing is lubricated with the lubricant. However, the lubricant composed of grease or the like sealed in this way impairs the bearing function of the rolling bearing as a result of acceleration of evaporation and deterioration of the lubrication function when the vacuum pump is operated in a high temperature environment. There was a problem that.

  The present invention has been made in view of such circumstances, and an object of the present invention is to maintain good lubrication of a rolling bearing attached to an inner back position of a support hole through which a rotating shaft is inserted and supported over a long period of time. Another object of the present invention is to provide a bearing device that can be used and a pump device including the bearing device.

  In order to achieve the above object, the invention according to claim 1 relating to the bearing device is rotated by a rolling bearing in which a rotating shaft is inserted into a support hole penetrating the bearing body, and the rotating shaft is mounted in the support hole. In the bearing device that is freely supported, an oil reservoir chamber in which lubricating oil is stored is provided outside the bearing body, and is attached to an inner back position in the support hole on the outer peripheral surface of the rotating shaft. A first lubricating oil passage having a pump function portion is formed from an outer peripheral surface portion corresponding to a position of a predetermined rolling bearing to an outer peripheral surface portion on one end side protruding into the oil reservoir chamber, and the inside of the bearing body or the rotary shaft The gist of the present invention is that a second lubricating oil passage that communicates between the oil reservoir chamber and the mounting position of the predetermined rolling bearing is formed in the interior.

  Therefore, in the first aspect of the present invention, when the rotating shaft rotates, the first lubricating oil passage having the pump function portion formed on the outer peripheral surface of the rotating shaft exhibits the pump action, and the bearing body Lubricating oil is sucked from the oil reservoir chamber via the second lubricating oil passage formed inside or inside the rotary shaft. As a result, the sucked lubricating oil reaches the predetermined rolling bearing attached to the inner back position in the support hole to lubricate the rolling bearing, and after the lubrication, the helical oil formed on the outer peripheral surface of the rotating shaft is lubricated. It returns to the oil reservoir chamber through the lubricating oil passage. In this manner, a lubricating oil circulation path including the first and second lubricating oil passages is formed between the predetermined rolling bearing attached to the inner back position in the support hole and the oil reservoir chamber. The lubricating function of the rolling bearing in the bearing device can be satisfactorily maintained by the lubricating oil that circulates and circulates through the circulation path.

  According to a second aspect of the present invention, in the bearing device according to the first aspect, the first lubricating oil passage has a spiral shape between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the support hole. The gist is that the passage is made. Therefore, in the invention according to claim 2, the predetermined rolling bearing is attached while the lubricating oil spirally flows between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the support hole as the rotating shaft rotates. It returns to the oil sump chamber from the inner back position in the support hole.

  According to a third aspect of the present invention, in the bearing device according to the first or second aspect, the pump function portion is formed on the outer peripheral surface of the rotating shaft that is in sliding contact with the inner peripheral surface of the support hole. The gist is that it is constituted by a spiral groove. Therefore, in the invention described in claim 3, if the spiral groove is formed on the outer peripheral surface of the rotating shaft, a lubricating oil passage that exhibits a pumping action can be easily formed. A good lubricating function can be obtained.

  According to a fourth aspect of the present invention, in the bearing device according to any one of the first to third aspects, the oil reservoir chamber is opposite to the predetermined rolling bearing in the support hole. The gist of the present invention is that an oil seal that restricts the flow of the lubricating oil through a clearance between the inner peripheral surface of the support hole and the outer peripheral surface of the rotating shaft is provided at the position on the side. Therefore, in the invention according to claim 4, the lubricating oil sucked to the inner depth position in the support hole through the lubricating oil passage for lubricating the predetermined rolling bearing leaks to the opposite side to the oil reservoir chamber. Can be well regulated by the oil seal.

  On the other hand, in the invention according to claim 5 related to the pump device, a rotating shaft that rotates based on a driving force of a driving source is inserted into a support hole that penetrates a bearing body provided in the housing, and the rotating shaft is inserted into the rotating shaft. A fluid transfer body accommodated in the pump chamber is connected to rotate integrally with the rotation shaft, and a rolling bearing for the rotation shaft inserted into the support hole is attached to an inner back position in the support hole. A pump device in which the fluid sucked from the outside into the pump chamber is discharged from the pump chamber to the outside after the fluid is sucked into the pump chamber by rotating the fluid transfer body based on the rotation of the rotating shaft. In the housing, an oil reservoir chamber in which lubricating oil is stored is provided at a position opposite to the pump chamber when viewed from the bearing body, and one end of the rotating shaft is provided in the oil reservoir chamber. The outer peripheral surface of the rotating shaft extends from the outer peripheral surface portion corresponding to the predetermined rolling bearing attached to the inner back position in the support hole to the outer peripheral surface portion on one end side protruding into the oil sump chamber. A second lubricating oil passage having a pump function portion is formed, and the second oil reservoir chamber and the rotary shaft are communicated between the oil reservoir chamber and the mounting position of the predetermined rolling bearing. The gist is that a lubricating oil passage is formed.

  Therefore, in the invention according to claim 5, when the rotary shaft rotates to suck the fluid into the pump chamber, the first lubricating oil passage having the pump function portion formed on the outer peripheral surface of the rotary shaft is the pump. The effect is exerted, and the lubricating oil is sucked from the oil reservoir through the second lubricating oil passage formed in the bearing body or the rotary shaft. As a result, the sucked lubricating oil reaches the predetermined rolling bearing attached to the inner back position in the support hole to lubricate the rolling bearing, and after the lubrication, the helical oil formed on the outer peripheral surface of the rotating shaft is lubricated. It returns to the oil reservoir chamber through the lubricating oil passage. As described above, when the pump device is operated to rotate the rotating shaft, the first and second lubricating oil passages are provided between the predetermined rolling bearing attached to the inner position in the support hole and the oil reservoir chamber. Therefore, the lubricating function of the bearing device is well maintained by the lubricating oil circulated through the circulating path. Therefore, the operating state of the pump device can be maintained well over a long period of time.

  According to a sixth aspect of the present invention, in the pump device according to the fifth aspect, the first lubricating oil passage has a spiral shape between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the support hole. The gist is that the passage is made. Therefore, in the invention according to claim 6, the predetermined rolling bearing is attached while the lubricating oil spirally flows between the outer peripheral surface of the rotary shaft and the inner peripheral surface of the support hole as the rotary shaft rotates. It returns to the oil sump chamber from the inner back position in the support hole.

  According to a seventh aspect of the present invention, in the pump device according to the fifth or sixth aspect, the pump function portion is formed on the outer peripheral surface of the rotary shaft that is in sliding contact with the inner peripheral surface of the support hole. The gist is that it is constituted by a spiral groove. Therefore, in the invention described in claim 7, if a spiral groove is formed on the outer peripheral surface of the rotating shaft inserted and supported in the support hole of the bearing body, a lubricating oil passage that exhibits a pump action can be easily formed. Therefore, a good lubricating function for the rolling bearing in the pump device can be obtained at low cost.

  The invention according to claim 8 is the pump device according to any one of claims 5 to 7, wherein the oil reservoir chamber is opposite to the predetermined rolling bearing in the support hole. The gist of the present invention is that an oil seal that restricts the flow of the lubricating oil through a clearance between the inner peripheral surface of the support hole and the outer peripheral surface of the rotating shaft is provided at the position on the side. Therefore, in the invention according to claim 8, the lubricating oil sucked to the inner depth position in the support hole through the lubricating oil passage to lubricate the predetermined rolling bearing leaks to the opposite side to the oil reservoir chamber, for example, It is possible to satisfactorily regulate by the oil seal that the fluid enters the pump chamber where the fluid is sucked and contaminates the pump chamber.

  According to the present invention, when applied to a bearing device, the lubrication of the rolling bearing attached to the inner deep position of the support hole through which the rotating shaft is inserted and supported can be satisfactorily maintained over a long period of time. And in the pump apparatus provided with such a bearing apparatus, the operating condition of the pump apparatus can be satisfactorily maintained over a long period of time.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is embodied in a horizontal screw-type vacuum pump and a bearing device included in the vacuum pump will be described with reference to FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, a screw type vacuum pump (hereinafter referred to as “pump”) 11 constituting a pump device in the present embodiment is a front end (FIGS. 1 and 2) of a cylindrical rotor housing 12. , A front housing 13 having a lid shape is joined to the left end, and a rear housing 14 having a plate shape is joined to the rear end (right end in FIGS. 1 and 2) of the rotor housing 12. A mounting hole 14a with a step is formed in the rear housing 14, and a bearing body 15 is assembled and fixed to the rear housing 14 by bolt fastening via the mounting hole 14a. The bearing body 15 is formed with a pair of cylindrical portions 16 protruding so as to be parallel to each other, and the bearing body 15 is a set in which both the cylindrical portions 16 protrude toward the inside of the rotor housing 12 with respect to the rear housing 14. It is fixed in an attached manner.

  In the rotor housing 12, a screw rotor 17 functioning as a fluid transfer body is rotatably fitted and supported on each cylindrical portion 16 of the bearing body 15. That is, each screw rotor 17 is fitted and supported by each cylindrical portion 16 in a cantilever shape with the bearing body 15 side as a base end side. Both the screw rotors 17 are in the form of screw gears in which screw grooves 17a are formed on the outer peripheral surface, and are housed in the rotor housing 12 so that the screw grooves 17a mesh with each other. That is, both the screw rotors 17 are configured so as to create a sealed space between the two screw grooves 17 a by engaging each other, and between the outer peripheral surface of each screw rotor 17 and the inner peripheral surface of the rotor housing 12. A pump chamber 18 is formed in the upper part.

  A pair of support holes 19 are formed through the bearing body 15 along the central axis of each cylindrical portion 16, and a rotation shaft 20 is inserted and supported in each support hole 19. Each rotating shaft 20 has a tip (left end in FIGS. 1 and 2) protruding into the pump chamber 18 from the support hole 19, and the screw rotor 17 is connected to the connecting plate 21 with respect to the tip of each rotating shaft 20. It is being fixed by bolt fastening via. That is, the screw rotor 17 is connected and fixed to the rotary shaft 20 so as to rotate integrally with the rotary shaft 20.

  A gear housing 22 having a bottomed cylindrical shape is assembled and fixed to the rear end of the rear housing 14. An oil reservoir chamber 23 is formed in the gear housing 22, and lubricating oil 24 is stored in the oil reservoir chamber 23 as shown in FIG. One end (the right end in FIGS. 1 and 2) 20a of each of the rotary shafts 20 protrudes into the oil reservoir chamber 23, and the gear 25 meshes with one end 20a which is the protruding end of each rotary shaft 20. It is fixed in the state. The gear housing 22 is provided with an electric motor 26 serving as a drive source. One of the rotating shafts 20 (the lower side in FIG. 1) is connected to the output shaft 26a of the electric motor 26. One end 20 a of the rotation shaft 20 is connected via a shaft coupling 27.

On the other hand, a suction port 28 for sucking an inert gas (fluid) such as F ₂ gas is formed in a substantially central portion of the front housing 13 so as to communicate with the pump chamber 18. In addition, as shown in FIG. 2, the exhaust gas for exhausting the inert gas is provided at the lower part of the rotor housing 12 in the width direction (the direction perpendicular to the paper surface in FIG. 2) on the side opposite to the suction port 28. An outlet 29 is formed so as to communicate with the pump chamber 18. A connecting flange 30, a muffler 31, a guide pipe 32, and a discharge pipe 33 are sequentially connected to the discharge port 29 on the lower surface side of the rotor housing 12, and the exhaust pipe 33 is connected to the exhaust gas treatment device (not shown). Inert gas is discharged.

Next, the bearing device provided in the pump 11 in the present embodiment will be described.
As shown in FIGS. 1 and 2, rolling bearings 34 and 35 are attached to the support hole 19 of the bearing body 15 at two front and rear locations along the axial direction of the rotary shaft 20. Each of the rolling bearings 34 and 35 supports a radial load or the like applied to the rotary shaft 20 and rotatably supports the rotary shaft 20. For example, ball bearings or roller bearings are used. In the present embodiment, these rolling bearings 34 and 35 and the bearing body 15 constitute the main part of the bearing device in the pump 11.

  Further, in the support hole 19 of the bearing body 15, the position corresponding to the opening end of the support hole 19 on the pump chamber 18 side (that is, the side opposite to the oil reservoir chamber 23 when viewed from the rolling bearing 35 on the front end side). At the position), an oil seal 36 is interposed between the outer peripheral surface of the rotary shaft 20 and the inner peripheral surface of the support hole 19. In the bearing device of the pump 11, the oil seal 36 allows the gas between the inside of the support hole 19 to which the rolling bearings 34 and 35 are attached and the inside of the pump chamber 18 from which the inert gas is sucked. The distribution of lubricating oil is regulated.

  Here, the lubrication method for the respective rolling bearings 34 and 35 attached in the support hole 19 will be described. The rear end side in the support hole 19 of the both rolling bearings 34 and 35 (the right end in FIGS. 1 and 2). In the case of the rolling bearing 34 attached to the side), the mounting position mode is the mounting position mode facing the oil reservoir chamber 23. Therefore, with respect to the rolling bearing 34, the rolling bearing 34 is caused by the splashing of the lubricating oil 24 that is caused by the gear 25 rotating based on the rotation of the rotating shaft 20 and splashing the lubricating oil 24 stored in the oil reservoir chamber 23. It is designed to be lubricated.

  On the other hand, in the case of the predetermined rolling bearing 35 attached to the front end side (the left end side in FIGS. 1 and 2) in the support hole 19, the attachment position mode is based on the rotation of the gear 25 from the oil reservoir chamber 23. It is set as the attachment position aspect with respect to the position where the splash oil supply does not reach, that is, the inner back position in the support hole 19. Therefore, it is necessary to lubricate the predetermined rolling bearing 35 by a lubricating method other than the splash lubrication based on the rotation of the gear 25. Therefore, in the present embodiment, the following lubricating oil circulation path is provided.

  That is, as shown in FIG. 1 and FIG. 2, a pump function that exerts a pump action as the rotary shaft 20 rotates on the outer peripheral surface of the rotary shaft 20 that is in sliding contact with the inner peripheral surface of the support hole 19. A spiral groove 37 as a portion is formed, and the spiral groove 37 forms a first lubricating oil passage having a spiral shape between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20. ing. This spiral groove 37 is on the one end 20a side projecting into the oil reservoir chamber 23 from the outer peripheral surface portion corresponding to the mounting position of the predetermined rolling bearing 35 on the front end side in the support hole 19 on the outer peripheral surface of the rotating shaft 20. Specifically, the outer peripheral surface portion is formed up to the outer peripheral surface portion that is in front of the mounting position of the rolling bearing 34 on the rear end side.

  Further, as shown in FIG. 2, the bearing body 15 including the cylindrical portion 16 has a space between the oil reservoir chamber 23 and a mounting position of the predetermined rolling bearing 35 on the front end side in the support hole 19. A communication path 38 for communication is formed. The communication path 38 forms a second lubricating oil passage through which the lubricating oil 24 stored in the oil reservoir chamber 23 can be guided to the mounting position of the predetermined rolling bearing 35. As a result, the lubricating oil 24 is circulated by the spiral groove 37 and the communication path 38 between the predetermined rolling bearing 35 attached to the front end side that is the inner back position in the support hole 19 and the oil reservoir chamber 23. A path will be formed. When the rotary shaft 20 rotates, the spiral groove 37 exhibits a pumping action, and the lubricating oil 24 is introduced from the oil reservoir chamber 23 to the mounting position of the predetermined rolling bearing 35 via the communication path 38. Then, it returns to the oil reservoir chamber 23 through a clearance between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20.

Then, next, the effect | action of the pump 11 which concerns on this embodiment comprised as mentioned above and the bearing apparatus with which the said pump 11 is provided is demonstrated below.
When each rotary shaft 20 is rotated by the driving force of the electric motor 26, both screw rotors 17 meshing with each rotary shaft 20 rotate, and an inert gas enters the pump chamber 18 from the outside through the suction port 28. Sucked. Then, the inert gas sucked into the pump chamber 18 is transferred toward the direction of the discharge port 29 through the pump chamber 18 while being compressed by the two screw rotors 17, and the pump chamber 18 passes through the discharge port 29 to enter the pump chamber 18. Is discharged from the discharge pipe 33 to an external exhaust gas treatment device or the like. Therefore, in the semiconductor manufacturing process, when the suction port 28 of the pump 11 is communicated with a work room or work container for performing various processes on the wafer (not shown), a clean vacuum environment is created in the work room or the like. Will be produced.

On the other hand, in the bearing device comprising the bearing body 15 and the rolling bearings 34, 35 provided in the pump 11, the following lubricating action is performed on the rolling bearings 34, 35.
That is, the gear 25 rotates in the oil reservoir chamber 23 based on the rotation of the rotating shaft 20, and the lubricating oil 24 stored in the oil reservoir chamber 23 jumps up. As a result, the rolling bearing 34 attached to the rear end side in the support hole 19 is lubricated by the splashing of the lubricating oil 24 splashed by the gear 25. It should be noted that the oil supply to the rolling bearing 34 by splashing the lubricating oil 24 stored in the oil reservoir chamber 23 is the gear 25 with respect to one end 20a of the rotary shaft 20 protruding into the oil reservoir chamber 23. Separately, a splasher (not shown) may be fastened and performed by the splasher.

  Further, when the rotary shaft 20 rotates, the spiral groove 37 formed on the outer peripheral surface of the rotary shaft 20 exhibits a function as an oil pump based on the rotation. That is, between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20, the front end in the support hole 19 is a portion corresponding to the outer peripheral surface portion where the spiral groove 37 of the rotary shaft 20 is formed. A pumping action of transferring fluid (for example, lubricating oil) from the mounting position of the predetermined rolling bearing 35 mounted on the side (that is, the inner back position in the support hole 19) toward the oil reservoir chamber 23 occurs.

  Further, when the spiral groove 37 functions as an oil pump, at the same time, the connecting path 38 formed in the bearing body 15 is connected to the front end in the support hole 19 from the oil reservoir chamber 23. A pumping action of transferring fluid (for example, lubricating oil) toward the mounting position of the predetermined rolling bearing 35 mounted on the side (that is, the inner back position in the support hole 19) occurs. As a result, the lubricating oil 24 stored in the oil reservoir chamber 23 is guided to the predetermined rolling bearing 35 through the communication path 38, and the predetermined rolling bearing 35 is lubricated by the guided lubricating oil 24. The The lubricating oil 24 that has lubricated the predetermined rolling bearing 35 is transferred to the oil reservoir chamber 23 through a clearance between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20 by the pumping action of the spiral groove 37. Is returned.

  As described above, when the rotating shaft 20 is rotated by the driving force of the electric motor 26, the spiral groove 37 and the communication between the predetermined rolling bearing 35 attached to the front end side in the support hole 19 and the oil reservoir chamber 23 are connected. A circulation path of the lubricating oil 24 composed of the path 38 is formed. The lubricating oil 24 is circulated and supplied to the predetermined rolling bearing 35 through the circulation path, whereby the predetermined rolling bearing 35 is cooled and lubricated. Therefore, even when the pump 11 is operated in a high temperature environment, the lubrication of the bearing device can be maintained well. The lubricating oil 24 that has lubricated the predetermined rolling bearing 35 is transferred to the oil sump chamber 23 through a clearance between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20 by the pumping action of the spiral groove 37. When returning, it passes through the mounting position of the rolling bearing 34 on the rear end side, which is lubricated by the splashing of oil, so that the rolling bearing 34 can be lubricated.

According to the above embodiment, the following effects can be obtained.
(1) Formed on the outer peripheral surface of the rotating shaft 20 with respect to a predetermined rolling bearing 35 attached to an inner position where the droplet oil supply from the oil reservoir chamber 23 does not reach in the support hole 19 through which the rotating shaft 20 is inserted and supported. Lubricating oil 24 can be circulated and supplied through a circulation path composed of the formed spiral groove 37 and a communication path 38 formed inside the bearing body 15, so that lubrication can be reliably achieved. Therefore, even when the pump 11 is operated in a high temperature environment, the predetermined rolling bearing 35 can be reliably lubricated and the operating state of the pump 11 can be maintained well over a long period of time.

  (2) Other than forming a connecting path 38 between the predetermined rolling bearing 35 on the front end side attached to the inner back position in the support hole 19 and the oil reservoir chamber 23 inside the bearing body 15, By simply forming the spiral groove 37 on the outer peripheral surface of the shaft 20, it is possible to obtain a pump action capable of circulatingly supplying the lubricating oil 24 to the predetermined rolling bearing 35. Accordingly, there is no need to separately provide a circulation pump device that causes an increase in the number of parts of the pump 11, so that an increase in manufacturing cost can be avoided and a pump 11 and a bearing device that can be operated for a long time can be obtained. be able to.

  (3) Lubricating oil 24 introduced to the predetermined rolling bearing 35 on the front end side in the support hole 19 by the pumping action of the spiral groove 37 based on the rotation of the rotation shaft 20 and the inner peripheral surface of the support hole 19 and the rotation shaft 20. The oil seal 36 can restrict the leakage to the pump chamber 18 side through the clearance with the outer peripheral surface. Accordingly, it is possible to prevent the occurrence of harmful effects such as contamination of the pump chamber 18 by the lubricating oil 24 or shortening of the lubricating life due to the lubricating oil 24 coming into contact with the inert gas.

  (4) Since each screw rotor 17 functioning as a fluid transfer body by rotating integrally with the rotary shaft 20 in the pump chamber 18 is supported in a cantilever shape on the cylindrical portion 16 of the bearing body 15, The configuration on the low pressure side (suction port 28 side) in the pump chamber 18 in the rotor housing 12 can be simplified. That is, in the case where the screw rotor 17 is supported at both ends, it is necessary to further provide another rolling bearing that rotatably supports the screw rotor 17 on the low pressure side (suction port 28 side) in the pump chamber 18. In order to prevent the separate rolling bearing from being corroded by the inert gas, it is necessary to forcibly supply nitrogen gas or the like to the mounting position of the separate rolling bearing. Accordingly, when the screw rotor 17 is supported at both ends, the overall configuration of the pump 11 is complicated and the manufacturing cost increases. In the present embodiment, the screw rotor 17 is supported in a cantilever shape. Therefore, an increase in manufacturing cost can be avoided.

(Second Embodiment)
Next, a second embodiment in which the present invention is embodied in a vertically installed screw type vacuum pump (pump device) and a bearing device provided in the vacuum pump will be described with reference to FIG. In the second embodiment, the pump 11 is a vertically installed type in contrast to the first embodiment in which the pump 11 is a horizontally installed type, and the communication path 38 forming the second lubricating oil passage is a bearing body. The difference is that the configuration is formed inside the rotary shaft 20 instead of inside the rotary shaft 20. Accordingly, in the following description of the second embodiment, portions different from the first embodiment will be mainly described, and the same configuration and corresponding configuration portions are the same as those in the first embodiment. Only the reference numerals are used for description, and redundant description of the same components is omitted.

  As shown in FIG. 3, the pump (vacuum pump) 11 of the present embodiment is of a vertically placed type. Therefore, when the pump is used, the front housing 13 in which the suction port 28 is formed is positioned above and the lubricating oil is used. The gear housing 22 storing 24 in the oil sump chamber 23 is installed so as to be positioned below. Therefore, the bearing body 15 is assembled and fixed to the stepped mounting hole 14a of the rear housing 14 in such a manner that the cylindrical portion 16 protrudes to the upper side where the pump chamber 18 is located. The rotary shaft 20 is inserted and supported in the support hole 19 in the bearing body 15 along the vertical direction, and the rolling bearings 34 are provided in the support hole 19 in two vertical locations along the axial direction of the rotary shaft 20. 35 is attached.

  Of the rolling bearings 34 and 35, the rolling bearing 34 on the lower end side in the support hole 19 is attached in the support hole 19 so as to face the oil reservoir chamber 23. On the other hand, the predetermined rolling bearing 35 on the upper end side in the support hole 19 is attached to an inner back position in the support hole 19 that is far away in the vertical direction when viewed from the oil reservoir chamber 23. An oil seal 36 is interposed between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20 at a position above the predetermined rolling bearing 35 on the upper end side.

  The rotary shaft 20 is inserted and supported in a support manner along the vertical direction with respect to the support hole 19 of the bearing body 15, and one end of the rotary shaft 20 protruding into the oil reservoir chamber 23 in the gear housing 22 (the main shaft). In the embodiment, the lower end 20 a is suspended so as to extend below the oil level of the lubricating oil 24 stored in the oil reservoir chamber 23. On the outer peripheral surface of the rotary shaft 20, as in the case of the first embodiment, the spiral groove 37 has a predetermined rolling bearing on the inner back position side (upper end side in the present embodiment) in the support hole 19. 35 is formed from the outer peripheral surface portion corresponding to the mounting position of 35 to the outer peripheral surface portion on the one end 20a side that projects into the oil reservoir chamber 23 (the portion that is in front of the mounting position of the rolling bearing 34 on the lower end side). That is, as in the case of the first embodiment, the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20 are formed by a spiral groove 37 serving as a pump function part that exhibits a pump action as the rotary shaft 20 rotates. A first lubricating oil passage having a spiral shape is formed between the two.

  In the first embodiment, the oil reservoir chamber 23 and the mounting position of the predetermined rolling bearing 35 on the inner back position side (the front end side in the first embodiment) in the support hole 19 are provided inside the bearing body 15. In the present embodiment, the communication path 38 is formed not inside the bearing body 15 but inside the rotating shaft 20. That is, as shown in FIG. 3, in the present embodiment, the connecting path 38 passes through the axis of the rotary shaft 20 from the lower end surface of the rotary shaft 20 to the inner back position side (upper end side) in the support hole 19. The predetermined rolling bearing 35 is formed up to the mounting position, and a second lubricating oil passage is formed with which the lubricating oil 24 can be introduced from the oil reservoir chamber 23 to the predetermined rolling bearing 35. Then, the circulation path of the lubricating oil 24 is provided between the predetermined rolling bearing 35 attached to the upper end side which is the inner back position in the support hole 19 and the oil reservoir chamber 23 by the spiral groove 37 and the communication path 38. To be formed.

  Therefore, in this embodiment, when the rotating shaft 20 rotates, the spiral groove 37 exhibits a pumping action as in the first embodiment, and the lubricating oil is removed from the oil reservoir chamber 23 via the communication path 38. After the oil 24 is introduced to the mounting position of the predetermined rolling bearing 35, it flows down into the oil reservoir chamber 23 through the clearance between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20. Further, the lubricating oil 24 also lubricates the rolling bearing 34 on the lower end side while flowing down into the oil reservoir chamber 23 and returning.

  Therefore, according to the present embodiment, the functions and effects described in (1) to (4) in the first embodiment can be obtained in the same manner, and further, the following specific functions and effects can be obtained. be able to.

  (5) The circulation path of the lubricating oil 24 functioning as an oil pump by the spiral groove 37 formed on the outer peripheral surface of the rotating shaft 20 and the connecting path 38 formed along the axis of the rotating shaft 20. Therefore, it is not necessary to form the communication path 38 serving as a lubricating oil path in the bearing body 15. Therefore, the present embodiment also replaces the existing rotating shaft of the existing pump 11 with the rotating shaft 20 in which the spiral groove 37 and the communication path 38 are formed. A good lubricating action on the predetermined rolling bearing 35 on the inner back position side (upper end side) obtained by the pump 11 and the bearing device can be similarly obtained.

  (6) Further, in the case of the vertical type pump 11, the gear 25 does not splash up the lubricating oil 24 in the oil sump chamber 23 during rotation as understood from FIG. The rolling bearing 34 cannot be lubricated by splash oil supply. However, in the present embodiment, after the predetermined rolling bearing 35 on the upper end side is lubricated, the lubrication flows down to the oil reservoir chamber 23 through the clearance between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20 and returns. The oil 24 can lubricate the rolling bearing 34 on the lower end side and the gear 25 fixed to the rotary shaft 20 below the rolling bearing 34.

The above embodiment may be changed to another embodiment (another example) as follows.
In each of the above embodiments, the screw rotor 17 may be a support mode in which both ends are supported in the pump chamber 18 instead of a cantilevered support mode.

  In each of the above embodiments, the oil seal 36 is not between the inner peripheral surface of the support hole 19 and the outer peripheral surface of the rotary shaft 20, for example, a screw into which the outer peripheral surface of the rotary shaft 20 and the rotary shaft 20 are fitted. It may be interposed between the inner peripheral surface of the rotor 17. In other words, the interposition position can be arbitrarily changed as long as it is an intervening mode capable of restricting leakage of the lubricating oil 24 that has lubricated the predetermined rolling bearing 35 inside the support hole 19 into the pump chamber 18. Is possible.

  In each of the above embodiments, instead of engraving the spiral groove 37 on the outer peripheral surface of the rotary shaft 20, the protrusion that spirals from the outer peripheral surface of the rotary shaft 20 is the inner peripheral surface of the support hole 19. The first lubricating oil passage may be formed so as to be in sliding contact with the ridge, and a spiral shape may be formed by the protrusion.

  In each of the above embodiments, the spiral groove 37 that exhibits a pumping action as a pump function unit may have a spiral number of 2 to 3 as long as the first lubrication passage can be configured as a spiral passage. It is not limited to what was illustrated in each drawing of each said embodiment.

  In each of the above embodiments, the pump function unit may be configured as follows in addition to being configured by the spiral groove 37 formed on the outer peripheral surface of the rotating shaft 20. For example, an annular groove is formed at a predetermined position on the inner peripheral surface of the support hole 19 from the predetermined rolling bearing 35 toward the oil reservoir chamber 23, and the outer periphery of the rotary shaft 20 is positioned so as to be positioned in the groove. A propeller is attached to the surface so as to rotate integrally with the rotary shaft 20. When the rotary shaft 20 rotates, the propeller integrally rotates in the concave groove to exert a pump function as a pump function unit, and the lubricating oil is provided between the outer peripheral surface of the rotary shaft and the inner peripheral surface of the support hole. You may make it promote a flow.

  In each of the above embodiments, the bearing body 15 is integrated with the rear housing 14, and the pair of cylindrical portions 16 project into the pump chamber 18 from the rear housing (= bearing body) 14 also serving as the bearing body. It may be provided as described above. In this way, the number of parts can be reduced.

  In each of the above embodiments, the cylindrical portion 16 is not formed to protrude from the bearing body 15 (or the rear housing 14 also serving as a bearing body), but at the tip of the rotary shaft 20 that protrudes from the bearing body 15 into the pump chamber 18. Alternatively, the screw rotor 17 may be connected so as to rotate integrally. In this case, in order to satisfactorily support the radial load from the rotating shaft 20 and the screw rotor 17 by the rolling bearings 34 and 35 attached to a plurality of axial positions in the support hole 19 of the bearing body 15, the bearing body is used. It is desirable that the axial thickness of 15 (or the rear housing 14 also serving as a bearing body) be larger than that in the above embodiments. In this case, a circulation path composed of the spiral groove 37 and the communication path 38 is provided for the predetermined rolling bearing 35 attached to the inner back position side in the support hole 19 as in the case of the above embodiments. It is only necessary to supply the lubricating oil 24.

  In each of the above-described embodiments, the fluid transfer body that rotates integrally with the rotary shaft 20 in the pump chamber 18 is not limited to the screw rotor 17 in the form of a screw gear, and may be a rotor having a double leaf shape in cross section. The pump 11 is not limited to a screw type vacuum pump, and may be another type of pump such as a roots type vacuum pump.

  In addition, the bearing device included in the pump 11 of each of the above embodiments is not limited to the bearing device in the vacuum pump, and can rotate a rotating shaft that rotates based on the driving force of a driving source such as a vane compressor or a swash plate compressor. The present invention can also be applied to various pump devices configured to include a supporting bearing device.

  In each of the above embodiments, the fluid sucked and transferred into the pump chamber 18 by the fluid transfer body (screw rotor 17) is not limited to an inert gas (gas) but may be a liquid such as hydraulic oil.

  In each of the above embodiments, when the rotary shaft 20 is rotated, the lubricating oil 24 from the oil reservoir chamber 23 is formed in the support hole 19 through the spiral groove 37 formed on the outer peripheral surface of the rotary shaft 20. It is good also as a structure returned to the oil sump chamber 23 via the connection path 38 formed in the inside of the bearing body 15 or the rotating shaft 20, after introducing oil to the predetermined rolling bearing 35 attached to the back position. In this case, as in the second embodiment, one end 20a of the rotary shaft 20 is configured to be immersed in the lubricating oil 24 stored in the oil reservoir chamber 23, and one end 20a of the rotary shaft 20 is configured. It is desirable that the spiral groove 37 is formed.

Next, a technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) The vacuum pump according to any one of claims 5 to 8, wherein the fluid transfer body is supported in a cantilever shape with the bearing body side as a base end side in the pump chamber.

  (B) The bearing body is formed with a cylindrical portion protruding into the pump chamber along the direction of penetration of the support hole, and the fluid transfer body is supported in a cantilever shape on the cylindrical portion. The said predetermined rolling bearing is attached to the inner back position in the support hole used as the front end side of the said cylindrical part, The any one of the said technical thoughts (a). Vacuum pump.

The cross-sectional view of the screw-type vacuum pump according to the first embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. The longitudinal cross-sectional view of the screw-type vacuum pump which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Vacuum pump (pump apparatus), 12 ... Rotor housing, 13 ... Front housing, 14 ... Rear housing, 15 ... Bearing body (component of bearing apparatus), 17 ... Screw rotor (fluid transfer body), 18 ... Pump chamber DESCRIPTION OF SYMBOLS 19 ... Support hole, 20 ... Rotating shaft, 20a ... One end, 22 ... Gear housing, 23 ... Oil reservoir chamber, 24 ... Lubricating oil, 26 ... Electric motor (drive source), 34 ... Rolling bearing (component of bearing device) ), 35... Predetermined rolling bearing (component of the bearing device), 36... Oil seal, 37... Spiral groove (pump function part, first lubricating oil passage), 38 .. communication path (second lubricating oil passage).

Claims (8)

In a bearing device in which a rotary shaft is inserted into a support hole penetrating the bearing body, and the rotary shaft is rotatably supported by a rolling bearing attached in the support hole.
An oil reservoir chamber in which lubricating oil is stored is provided outside the bearing body, and an outer peripheral surface portion corresponding to a predetermined rolling bearing attached to an inner back position in the support hole is provided on the outer peripheral surface of the rotating shaft. A first lubricating oil passage having a pump function part is formed over an outer peripheral surface portion on one end side protruding into the oil reservoir chamber, and the oil reservoir chamber and the predetermined shaft are provided in the bearing body or the rotary shaft. A bearing device in which a second lubricating oil passage communicating with a mounting position of a rolling bearing is formed. The bearing device according to claim 1, wherein the first lubricating oil passage has a spiral passage configuration between an outer peripheral surface of the rotating shaft and an inner peripheral surface of the support hole. The bearing device according to claim 1, wherein the pump function unit is configured by a spiral groove formed on an outer peripheral surface of a rotating shaft that is in sliding contact with an inner peripheral surface of the support hole. Lubricating oil is placed in the support hole at a position opposite to the oil reservoir chamber when viewed from the predetermined rolling bearing through a clearance between the inner peripheral surface of the support hole and the outer peripheral surface of the rotary shaft. The bearing apparatus as described in any one of Claims 1-3 in which the oil seal which regulates distribution | circulation is provided. A rotating shaft that rotates based on the driving force of the driving source is inserted into a support hole that penetrates the bearing body provided in the housing, and the fluid transfer body housed in the pump chamber rotates integrally with the rotating shaft. And a rolling bearing with respect to the rotating shaft inserted into the supporting hole is attached to the inner back position in the supporting hole, and the fluid transfer body rotates based on the rotation of the rotating shaft, In the pump apparatus in which the fluid sucked into the pump chamber from the outside is discharged from the pump chamber to the outside after being transferred to the discharge side of the pump chamber,
In the housing, an oil reservoir chamber in which lubricating oil is stored at a position opposite to the pump chamber as viewed from the bearing body is provided, and one end of the rotating shaft protrudes into the oil reservoir chamber, On the outer peripheral surface of the rotating shaft, a pump function unit is provided from an outer peripheral surface portion corresponding to a position of a predetermined rolling bearing attached to an inner back position in the support hole to an outer peripheral surface portion on one end side protruding into the oil sump chamber. A first lubricating oil passage having a second lubricating oil passage communicating between the oil reservoir chamber and the mounting position of the predetermined rolling bearing is formed in the bearing body or the rotary shaft. Formed pumping device. The pump device according to claim 5, wherein the first lubricating oil passage has a spiral passage configuration between an outer peripheral surface of the rotating shaft and an inner peripheral surface of the support hole. The pump device according to claim 5 or 6, wherein the pump function unit is configured by a spiral groove formed on an outer peripheral surface of a rotating shaft that is in sliding contact with an inner peripheral surface of the support hole. Lubricating oil is placed in the support hole at a position opposite to the oil reservoir chamber when viewed from the predetermined rolling bearing through a clearance between the inner peripheral surface of the support hole and the outer peripheral surface of the rotary shaft. The pump device according to any one of claims 5 to 7, further comprising an oil seal that restricts circulation.

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