Spindle device, grinding device, and cutting machining device

Abstract

In the present invention, while a rotary shaft is stationary or rotating at a low speed, a lip part is brought into pressure contact with a contact surface provided on a housing to seal between the rotary shaft on the leading end side of a device and the housing, and the lip part is separated from the contact surface to release the sealing when the rotary shaft rotates at a prescribed rotation speed exceeding the low-speed rotation or higher. The present invention comprises a deformation reduction member that limits deformation of the lip part while the rotary shaft is rotating. The housing is provided with an outer-diameter-side flow path through which air sucked into the device from the outside flows in the device, and the outer-diameter-side flow path is provided with an outer-diameter-side spiral passage. An air discharge path for discharging air from the leading end side of the device is in communication with the outer-diameter-side flow path, and a sealing device is disposed in the air discharge path. In addition to the centrifugal force of the rotary shaft in rotation, the air flowing through the outer-diameter-side flow path acts at the time when the lip part of the sealing device is separated from the contact surface.

Description

Spindle device, grinding device, and cutting device

[0001] The present invention relates to a spindle device, a grinding device, and a cutting device.

[0002] Conventionally, in a device that rotates a tool for machining, a spindle device in which a tool is detachably attached to a rotatable spindle is known. The spindle device generally includes a rotating part supported by bearings and a fixed part other than this rotating part. Then, various machining tools (for example, grinding wheels, cutting tools, etc.) are attached to the tip of the rotating shaft that constitutes the rotating part, and machining (polishing, cutting, etc.) is performed on the workpiece with these machining tools.

[0003] Therefore, there was a risk that foreign matter such as coolant or chips might enter the spindle device from the clearance between the rotating part and the fixed part during machining. If foreign matter enters the spindle device in this way, the rotation of the rotating shaft may not be smooth, a large load may be applied, and the spindle device may be damaged.

[0004] Conventionally, in order to prevent the intrusion of coolant, chips, etc. inside, there is a device in which an air chamber is provided in the housing so that air can be discharged from this air chamber to the outside of the housing. In this case, a lip seal is externally fitted and supported on the spindle (rotating shaft) in the air chamber, and the lip of the lip seal is brought into contact with the inner peripheral surface of the housing, and the lip is configured to be separated from the inner peripheral surface of the housing by centrifugal force as the rotating shaft rotates (Patent Document 1).

[0005] In the invention described in Patent Document 1, when the spindle rotation is stopped and no air is supplied to the air chamber, the gap between the inner surface of the housing and the outer surface of the spindle is sealed by a lip within the air chamber. Therefore, coolant, chips, etc. that enter the air chamber through the gap between the housing and the spindle are prevented from entering the bearing side beyond the air chamber by the lip seal. Furthermore, when the spindle is rotating, the centrifugal force accompanying the rotation of the spindle ensures that the entire lip of the lip seal separates reliably from the inner surface of the housing. In this state, the air supplied to the air chamber from the air supply passage is discharged to the outside of the housing through a gap formed between the housing and the spindle on the tip side of the air chamber, and the pressure of this air prevents coolant, chips, etc. from entering the inside of the spindle head through this gap.

[0006] In addition, conventional cutting devices have an air seal exhaust passage provided between a mounting member for attaching a cutting blade and a spindle housing, and a sealing member that can open and close the outlet of this air seal exhaust passage (Patent Document 2).

[0007] In the invention described in Patent Document 2, when air is supplied to the air bearing, the air is ejected through the gap between the spindle housing and the spindle on the mounting member side, and through the air seal exhaust passage, thereby preventing foreign matter from entering due to the pressure of the air. On the other hand, when air is not supplied to the air bearing and the air seal is not functioning, the outlet of the air seal exhaust passage can be blocked by the sealing member. This prevents foreign matter from entering the air seal exhaust passage from the outside.

[0008] Furthermore, conventionally, there is a spindle sealing structure in a machine tool in which a gap exists between the spindle (rotating shaft) or a member fixed to the front end of the spindle and the front end of the shaft holding member (Patent Document 3). In this case, a pressurized section is provided that pressurizes gas into the gap from the inside of the shaft holding member as the spindle rotates, a secondary pressurized section that pressurizes gas as the spindle rotates, and a bias passage is provided that guides the gas pressurized by the secondary pressurized section to the upstream side of the pressurized section, bypassing the bearing member.

[0009] In the device described in Patent Document 3, the pumping action in the pumping section is reinforced, and the spray pressure from the gap is effectively increased. Moreover, the gas pumped in the auxiliary pumping section does not pass through the space inside the bearing member, and therefore, even when the bearing member is lubricated with grease, deterioration of the grease can be prevented.

[0010] Japanese Patent Publication No. 2007-223008, Japanese Patent Publication No. 2005-59151, Japanese Patent No. 3745584

[0011] Patent documents 1 and 2 use a V-ring as a sealing member. The V-ring consists of a main body and a flexible conical lip connected by an elastic hinge. As such, the lip provides sealing when it is in close contact with the lip-compatible surface, and a gap is formed between the lip and the lip-compatible surface when the lip separates from the lip-compatible surface, allowing fluid to flow in and out.

[0012] In other words, when the lip is in close contact with the lip-compatible surface to provide a seal, the elastic restoring force of the lip maintains the close contact. However, when fluid outflow or inflow is permitted, it is necessary to apply an external force to the lip in a direction that separates it from the lip-compatible surface, thus resisting the elastic restoring force.

[0013] However, in the V-rings described in Patent Documents 1 and 2, the lip may separate significantly from the lip-contacting surface depending on the applied external force. In the case of such plastic deformation, even if the external force separating the lip from the lip-contacting surface is released, the lip may no longer be in close contact with the lip-contacting surface, or the sealing member itself may be damaged due to the deformation of the lip.

[0014] Furthermore, the method described in Patent Document 3 does not use the sealing members used in Patent Documents 1 and 2, but its structure is complex. As a result, it is less productive.

[0015] Therefore, the present invention provides a spindle device, a grinding device, and a cutting device that can suppress (limit) the deformation of the sealing member and exhibit a stable sealing function over a long period of time.

[0016] The first spindle device of the present invention is a spindle device comprising a rotating shaft on which an object can be mounted at its tip, a housing that rotatably supports the rotating shaft via a bearing, and a sealing device disposed between the rotating shaft at the tip of the device and the housing, wherein when the rotating shaft is stationary or rotating at a low speed, the lip portion of the sealing device presses against a contact surface provided on the housing, sealing the space between the rotating shaft at the tip of the device and the housing, and when the rotating shaft rotates at a predetermined rotational speed or higher than the low speed, the centrifugal force accompanying the rotating shaft causes the lip portion to separate from the contact surface, releasing the seal, and when the rotating shaft rotates, the lip The device is equipped with a deformation-restricting member that limits the deformation of the part, and further, the housing is provided with an outer diameter side passage through which air drawn into the device from the outside flows inside the device, and an outer diameter side spiral passage is provided on the outer diameter side of the bearing that rotatably supports the rotating shaft in the outer diameter side passage, and an air discharge passage that discharges air from at least the tip side of the device is connected to the outer diameter side passage, and the seal device is arranged in the air discharge passage, and when the lip portion of the seal device separates from the contact surface, the air pressure of the air that has flowed through the outer diameter side passage acts in addition to the centrifugal force when the rotating shaft rotates. Here, the mounted object is various processing tools (for example, grinding wheels and cutting tools, etc.), and in this spindle device, processing (polishing, cutting, etc.) is performed on the workpiece using these processing tools.

[0017] The second spindle device of the present invention is a spindle device comprising a rotating shaft on which an object can be mounted at its tip, a housing that rotatably supports the rotating shaft via a bearing, and a sealing device disposed between the rotating shaft on the tip side of the device and the housing, wherein when the rotating shaft is stationary or rotating at a low speed, the lip portion of the sealing device presses against a contact surface provided on the housing, sealing the space between the rotating shaft on the tip side of the device and the housing, and when the rotating shaft exceeds a predetermined rotational speed beyond the low speed, the centrifugal force accompanying the rotating shaft causes the lip portion to separate from the contact surface, releasing the seal, and when the rotating shaft rotates, the lip portion The device is equipped with a deformation-restricting member that limits the deformation of the lip portion, and further, the rotating shaft is provided with an inner diameter passage through which air drawn into the device from the outside flows inside the device, and an inner diameter spiral-shaped passage is provided on the inner diameter side of the bearing that rotatably supports the rotating shaft in the inner diameter passage, and an air discharge passage that discharges air from at least the tip side of the device is connected to the inner diameter passage, and the sealing device is arranged in the air discharge passage, and when the lip portion of the sealing device separates from the contact surface, the air pressure of the air that has flowed through the inner diameter passage acts in addition to the centrifugal force when the rotating shaft rotates.

[0018] A third spindle device of the present invention is a spindle device comprising a rotating shaft on which an object can be mounted at its tip, a housing that rotatably supports the rotating shaft via a bearing, and a sealing device disposed between the rotating shaft at the tip of the device and the housing, wherein when the rotating shaft is stationary or rotating at a low speed, the lip portion of the sealing device presses against a contact surface provided on the housing to seal the space between the rotating shaft at the tip of the device and the housing, and when the rotating shaft exceeds a predetermined rotational speed beyond the low speed, the centrifugal force associated with the rotating shaft causes the lip portion to separate from the contact surface, thereby releasing the seal, and a deformation suppressing member is provided to limit the deformation of the lip portion when the rotating shaft rotates, and furthermore, the housing has an outer diameter passage diameter through which air drawn into the inside of the device from the outside flows inside the device A passage is provided, and an outer diameter side spiral passage is provided on the outer diameter side of the bearing that rotatably supports the rotating shaft in the outer diameter side passage. Furthermore, an inner diameter side passage is provided on the rotating shaft through which air drawn into the inside of the device flows, and an inner diameter side spiral passage is provided on the inner diameter side of the bearing that rotatably supports the rotating shaft in the inner diameter side passage. An air discharge passage that discharges air from at least the tip side of the device is connected to the outer diameter side passage and the inner diameter side passage, and the sealing device is arranged in the air discharge passage. When the lip portion of the sealing device separates from the contact surface, the air pressure of the air that has flowed through the outer diameter side passage and the inner diameter side passage acts in addition to the centrifugal force when the rotating shaft rotates. Here, the mounted objects are various processing tools (for example, grinding wheels and cutting tools), and in this spindle device, processing (grinding, cutting, etc.) is performed on the workpiece using these processing tools. Furthermore, in the third spindle device, the mounted objects are various processing tools (for example, grinding wheels and cutting tools), and in this spindle device, processing (polishing, cutting, etc.) is performed on the workpiece using these processing tools.

[0019] In the first, second, and third spindle devices, when the rotating shaft is stationary or rotating at a low speed, the lip portion presses against the contact surface provided on the housing, sealing the space between the rotating shaft at the tip of the device and the housing. When the rotating shaft exceeds a predetermined rotational speed, the centrifugal force associated with the rotating shaft causes the lip portion to separate from the contact surface, releasing the seal. Therefore, low-speed rotation of the rotating shaft refers to rotation at a speed in which the lip portion does not separate from the contact surface. The predetermined rotational speed is a speed exceeding the low speed, at which the lip portion separates from the contact surface. An example of a speed above the predetermined rotational speed is 5000 min. -1 That concludes the explanation. Furthermore, deformation refers to deformation caused by damage or deformation that does not return to its original shape due to plastic deformation, etc. In other words, in the absence of a deformation suppressing member, if a force (external force) that separates the contact surface is applied and then the force (external force) that causes separation is removed, the lip portion will not return to its original state due to its restoring force, and there is a risk that the air discharge passage will remain open. In contrast, the deformation that occurs when the lip portion separates from the contact surface that is pressed against the housing, causing the air discharge passage to open and allowing fluid to be ejected from both axial ends of the housing, is deformation due to elastic deformation. When the force (external force) that causes this deformation is removed, the lip portion will return to its original state due to its restoring force, thus blocking the air discharge passage. For this reason, when the sealing device is equipped with a deformation suppressing member, deformation that does not return to its original shape due to plastic deformation, etc., is suppressed (limited), while deformation due to elastic deformation is permitted.

[0020] Therefore, in the first, second, and third spindle devices according to the present invention, the air discharge passage is blocked when the rotating shaft is stationary, thus preventing foreign matter such as processing fluid and chips from entering the sealing device. Furthermore, even when the rotating shaft is rotating, the fluid is ejected from both axial ends of the housing, so even in this state, the entry of foreign matter into the sealing device can be prevented. In addition, since the deformation suppressing member is fitted into the circumferential groove of the sealing member, deformation of the lip portion (deformation that does not return to its original shape due to plastic deformation, etc.) can be suppressed (limited).

[0021] In the first spindle device, an outer diameter side passage is provided on the outer diameter side of the bearing, having an outer diameter side helical passage, so that air flows helically around the outer circumference of the bearing, effectively cooling the bearing by air. In the second spindle device, an inner diameter side passage is provided on the inner diameter side of the bearing, having an inner diameter side helical passage, so that air flows helically around the inner circumference of the bearing, effectively cooling the bearing by air. In the third spindle device, an outer diameter side passage is provided on the outer diameter side of the bearing, having an outer diameter side helical passage, and an inner diameter side passage is provided on the inner diameter side of the bearing, so that air flows helically around the outer and inner circumferences of the bearing, allowing the bearing to be particularly effectively cooled by air.

[0022] In the first spindle device and the third spindle device, an air discharge passage for discharging air from the rear end of the device is connected to the outer diameter side passage, and the sealing device is arranged in the air discharge passage. When the lip portion of the sealing device separates from the contact surface, the air pressure of the air flowing through the outer diameter side passage and the inner diameter side passage acts in addition to the centrifugal force during the rotation of the rotating shaft.

[0023] In the second and third spindle devices, an air discharge passage for discharging air from the rear end of the device is connected to the inner diameter passage, and the sealing device is arranged in the air discharge passage. When the lip portion of the sealing device separates from the contact surface, the air pressure of the air flowing through the outer diameter passage and the inner diameter passage acts in addition to the centrifugal force during the rotation of the rotating shaft.

[0024] Thus, in devices that have air discharge passages that discharge air from both the front and rear ends, it is possible to prevent foreign matter from entering the sealing device whether the rotating shaft is rotating or not, thereby preventing the device from being shortened due to foreign matter entering the device.

[0025] The device may also be equipped with a fan device that rotates in conjunction with the rotation of the rotating shaft to draw air from the outside into the device. In this way, a device equipped with a fan device can reliably draw in outside air into the device, and can reliably prevent foreign matter from entering the sealing device.

[0026] The grinding apparatus according to the present invention is a grinding apparatus equipped with the spindle device, wherein the mounted object attached to the tip of the rotating shaft is a grinding wheel. In the grinding apparatus according to the present invention, whether the rotating shaft is stopped or rotating, the inflow of foreign matter into the air discharge passage can be prevented, and the inflow of foreign matter into the grinding apparatus can be avoided.

[0027] The cutting apparatus according to the present invention is a cutting apparatus equipped with the spindle device, wherein the mounted object attached to the tip of the rotating shaft is a cutting tool. In the cutting apparatus according to the present invention, whether the rotating shaft is stopped or rotating, the inflow of foreign matter into the air discharge passage can be prevented, and the inflow of foreign matter into the cutting apparatus can be avoided.

[0028] This invention prevents foreign matter from entering the sealing device whether the rotating shaft is rotating or not, thus preventing the device from being shortened due to foreign matter intrusion. Furthermore, since the lip portion does not deform (deformation that does not return to its original shape due to plastic deformation, etc.), the lifespan of the sealing member can be extended. In particular, when rotating, the lip portion separates from the lip contact surface of the mating side (in this case, the separation is due to elastic deformation), eliminating frictional resistance caused by contact or pressure contact, suppressing heat generation in the rotating part (rotating shaft side) and the fixed part (housing side), and effectively preventing premature failure of bearings, etc., due to temperature rise of components inside the device (for example, bearings that rotatably support the rotating shaft). Moreover, when the rotating shaft is stopped, there is no need to eject fluid such as compressed air, so the consumption of fluid such as compressed air can be reduced, contributing to cost reduction.

[0029] Furthermore, by having helical passages on both the outer and inner diameters, the bearing can be effectively air-cooled to allow the rotating shaft to rotate freely. This suppresses the temperature rise of the bearing during rotation, prevents deterioration of the lubrication condition inside the bearing, and improves the bearing's lifespan.

[0030] This is a cross-sectional view of the first spindle device according to the present invention. This is an enlarged cross-sectional view showing the airflow drawn into the inside of the first spindle device. This is an enlarged cross-sectional view showing the front seal device with the rotating shaft not rotating. This is an enlarged cross-sectional view showing the front seal device with the rotating shaft rotating. This is an enlarged cross-sectional view showing the rear seal device with the rotating shaft not rotating. This is an enlarged cross-sectional view showing the rear seal device with the rotating shaft rotating. This is an enlarged cross-sectional view showing the airflow drawn into the inside of the second spindle device. This is a simplified view showing the rear cover member as seen from the rear of the spindle device. This is a half-view perspective view showing the rear cover member. This is a simplified view showing the front cover member as seen from the front of the spindle device. This is a half-view perspective view showing the front cover member. This is an enlarged cross-sectional view showing the airflow drawn into the inside of the third spindle device. This is a simplified view of the fan device of the third spindle device. This is an enlarged cross-sectional view showing the airflow drawn into the inside of the fourth spindle device. This is a simplified view of the fan device of the fourth spindle device. This is an enlarged cross-sectional view showing the airflow drawn into the inside of the fifth spindle device. This is a simplified diagram of the fan mechanism of the fifth spindle device.

[0031] Embodiments of the present invention will be described below with reference to Figures 1 to 13. Figure 1 is a cross-sectional view of the spindle device according to the present invention, and Figure 2 is an enlarged cross-sectional view thereof. The spindle device comprises a rotating shaft 1 and a housing 5 that rotatably supports the rotating shaft 1 via a pair of bearings 2, 2 at the front end and a pair of bearings 3, 3 at the rear end. The rotating shaft 1 is rotated around its axis by the rotational driving force of an external power source such as a motor (not shown) transmitted via a power transmission mechanism 4. The power transmission mechanism 4 can be a known or publicly used gear mechanism, belt mechanism, or coupling mechanism, etc.

[0032] On the side of the rotating shaft 1 where the reaction force transmission mechanism is located (i.e., the front end), a load (not shown) is directly or indirectly mounted to the mounting portion 1a. The spindle device 1 also has an outer diameter passage path 6 and an inner diameter circulation path 7 through which a fluid (air) flows. The housing 5 comprises a cylindrical body 5a that constitutes the housing body and lid members 5b and 5c that close both axial openings of the cylindrical body 5a. The lid members 5b and 5c are attached to the rotating shaft 1 side and rotate integrally with the rotating shaft 1. Here, the load refers to various processing tools (for example, grinding wheels and cutting tools), and in this spindle device, these processing tools are used to perform processing (polishing, cutting, etc.) on the workpiece.

[0033] Incidentally, the outer diameter passage 6 has an intermediate passage 6a provided in the axial middle of the body of the cylindrical body 5a, and an injection passage 6b for injecting the intermediate passage 6a is connected to the middle of this intermediate passage 6a at the axial middle position of the body of the housing 5. For this reason, the outer diameter passage 6 includes a tip-side passage 6A on the tip side of the injection passage 6b and a rear-end-side passage 6B on the rear end side of the injection passage 6b.

[0034] The tip-side passage 6A includes a first axial passage 6A1 extending from the injection passage 6b toward the tip, a first radial passage 6A2 extending radially inward from the tip of the first axial passage 6A1, an outer diameter side helical passage 6A3 disposed on the outer diameter side of the bearings 2, 2 from the first radial passage 6A2, a second radial passage 6A4 extending radially outward from the tip of the outer diameter side helical passage 6A3, an axial short passage 6A5 extending toward the tip from the outer diameter side end of the second radial passage 6A4, and a third radial passage 6A6 extending radially inward from the tip of the axial short passage 6A5.

[0035] The rear end passage 6B includes a first axial passage 6B1 extending from the injection passage 6b to the rear end, a first radial passage 6B2 extending radially inward from the rear end of the first axial passage 6B1, an outer diameter spiral passage 6B3 disposed on the outer diameter side of the bearings 3, 3 from the first radial passage 6B2, a second radial passage 6B4 extending radially outward from the rear end of the outer diameter spiral passage 6A3, an axial short passage 6B5 extending from the outer diameter end of the second radial passage 6B4 to the rear end, and a third radial passage 6B6 extending radially inward from the rear end of the axial short passage 6B5.

[0036] Furthermore, as shown in Figure 2, the front pair of bearings 2a, 2a and the rear pair of bearings 3a, 3b each consist of inner rings 2a1, 2b1, 3a1, 3b1, outer rings 2a2, 2b2, 3a2, 3b2, and balls 2a3, 2b3, 3a3, 3b3 interposed between the inner and outer rings. Between the front pair of bearings 2a, 2b and between the rear pair of bearings 3a, 3b, there are spacers 41a, 41b interposed between the inner rings and spacers 42a, 42b interposed between the outer rings.

[0037] Incidentally, the outer diameter side helical passage 6A3 on the tip side is composed of a helical groove 44a provided at the tip of the inner circumferential surface of the housing 5, and the outer diameter surfaces of the outer rings 2a2 and 2b2 of the bearings 2a and 2b, and the spacer 42a. Furthermore, the rear end edge of the outer diameter side helical passage 6A3 is connected to the first radial passage 6A2, and the tip edge of the outer diameter side helical passage 6A3 is connected to the second radial passage 6A4.

[0038] The rear-end outer diameter helical passage 6A3 is composed of a helical groove 44b provided at the rear end of the inner circumferential surface of the housing 5, and the outer diameter surfaces of the outer rings 3a2 and 3b2 of the bearings 3a and 3b, and the spacer 42b. The leading edge of the outer diameter helical passage 6B3 is connected to the first radial passage 6B2, and the rear end edge of the outer diameter helical passage 6B3 is connected to the second radial passage 6B4.

[0039] The front end surface of the housing 5 is provided with a circumferential notch 30 into which one of the lid members 5b is fitted. In this case, the circumferential notch 30 consists of a large diameter portion 30a on the opening side and a small diameter portion 30b on the inner side, and the front (tip side) lid member 5b is rotatably fitted into the large diameter portion 30a. Here, the large diameter portion 30a is a flat ring-shaped space consisting of an axial inner diameter surface 30a1 of the inner diameter portion on the outer diameter side and a radial end surface 30a2 which is the bottom, and the small diameter portion 30b is a flat ring-shaped space consisting of an axial inner diameter surface 30b1 of the inner diameter portion on the outer diameter side and a radial end surface 30b2 which is the bottom, and the diameter dimension of the large diameter portion 30a is larger than the diameter dimension of the small diameter portion 30b, and the depth dimension of the large diameter portion 30a is shallower than the depth dimension of the small diameter portion 30b. The front cover member 5b is rotatably fitted into the circumferential notch 30.

[0040] The front cover member 5b has a disc-shaped flat plate body 31 and an inner flange portion 32 on the inner end surface of the flat plate body 31. The flat plate body 31 is fitted into the large diameter portion 30a of the notch portion 30 with the inner flange portion 32 fitted into the small diameter portion 30b. A bearing inner ring retainer 33 is interposed between the front row bearing 2 (2a) and the cover member 5b. The bearing inner ring retainer 33 is provided with a hole 33a that communicates with the front branch path 7b of the inner diameter side flow path 7 of the rotating shaft 1. This hole 33a communicates with the space 34 between the front row bearing 2a and the bearing inner ring retainer 33. In this case, the third radial passage 6A6 of the tip-side passage 6A of the outer diameter side passage 6 communicates with the space 34.

[0041] Furthermore, the rear end surface of the housing 5 is provided with a circumferential notch 35 into which the rear (rear end side) lid member 5c is fitted. In this case, the large diameter portion 35a is a flat ring-shaped space consisting of the axial inner diameter surface 35a1 of the outer diameter side inner diameter portion and the radial end surface 35a2 which is the bottom, and the small diameter portion 35b is a flat ring-shaped space consisting of the axial inner diameter surface 35b1 of the outer diameter side inner diameter portion and the radial end surface 35b2 which is the bottom. The diameter dimension of the large diameter portion 35a is larger than the diameter dimension of the small diameter portion 30b, and the depth dimension of the large diameter portion 35a is shallower than the depth dimension of the small diameter portion 35b. The rear lid member 5c is rotatably fitted into the circumferential notch 35.

[0042] The rear cover member 5b has a disc-shaped flat plate body 36 and an inner flange portion 37 on the inner end surface of the flat plate body 36. The flat plate body 36 is fitted into the large diameter portion 35a with the inner flange portion 37 fitted into the small diameter portion 35b. A bearing inner ring retainer 38 is interposed between the last row of bearings 3b and the cover member 5c. The bearing inner ring retainer 38 is provided with a hole that constitutes the fifth radial passage 76i of the inner diameter side flow path 7 of the rotating shaft 1, which will be described later. This hole communicates with the space 39 between the last row of bearings 3b and the bearing inner ring retainer 38. In this case, the third radial passage 6B6 of the rear end side passage 6B of the outer diameter side passage 6 communicates with the space 39.

[0043] The inner diameter passage 7 includes a main channel 7a arranged along the axis of the rotating shaft 1, and the main channel 7a is provided with a front-end passage 7A and a rear-end passage 7B.

[0044] The tip-side passage 7A includes a first radially extending passage 7A1 extending in the radial direction from the tip side of the main flow portion 7a, and an inner diameter side spiral-shaped passage 7A2 extending from the first radially extending passage 7A1 toward the tip side, and a second radially extending passage 7A3 extending radially outward from the inner diameter side spiral-shaped passage 7A2. And this second radially extending passage 7A3 communicates with the space 34 between the bearing 2a in the frontmost row and the bearing inner ring retainer 38.

[0045] The rear-end side passage 7B includes a first radially extending passage 7B1 extending in the radial direction from the rear-end side of the main flow portion 7a, and an inner diameter side spiral-shaped passage 7B2 extending from the first radially extending passage 7B1 toward the rear-end side, and a second radially extending passage 7B3 extending radially outward from the inner diameter side spiral-shaped passage 7B2. And this second radially extending passage 7A3 communicates with the space 39 between the bearing 3b in the rearmost row and the bearing inner ring retainer 38.

[0046] And the injection path 6b and the main flow portion 7a of the inner diameter side passage 7 are connected to a fluid supply mechanism (not shown) having a fluid supply source. In this case, as the fluid, in this embodiment, it is compressed air, so the fluid supply source of the fluid supply mechanism is an air compressor.

[0047] Further, as shown in FIGS. 3A, 3B, 4A, and 4B, seal members 51 and 52 as seal devices are attached to the respective lid members 5b and 5c. The seal members 51 and 52 are composed of main body portions 51a and 52a made of ring members, and ring-shaped lip portions 51c and 52c continuously provided from the main body portions 51a and 52a through circumferential concave grooves 51b and 52b. That is, in this case, the seal members 51 and 52 use so-called V-rings.

[0048] In this case, a ring-shaped groove 53 is formed on the inner surface of the lid member 5b, and the main body portion 51a of the sealing member 51 is fitted into this groove 53, with the lip portion 51c having close or contact end with the cylindrical body 5a. The contact area of ​​the lip portion 51c is the contact surface 30b1, which is the bottom surface of the small diameter portion 30b on the inner side of the circumferential notch portion 30 of the cylindrical body 5a. The lip portion 51c is also inclined at a predetermined angle with respect to the axial direction of the housing. In this case, the inclination angle θ is set to, for example, 50° to 60°. The tip of the lip portion 51c is an annular end surface 51c1 that makes surface contact with the contact surface 30b1 of the cylindrical body 5a.

[0049] Furthermore, a deformation suppression member (deformation suppression ring) 55 is fitted into the circumferential groove 51b of the sealing member 51 to receive the lip portion 51c and suppress (limit) deformation from the contact surface 30b1 (i.e., deformation of the lip portion 51c) when the rotating shaft rotates. Here, deformation refers to deformation due to damage or deformation that does not return to its original shape due to plastic deformation, etc. In other words, in the absence of the deformation suppression member 55, if a force (external force) that separates the contact surface is applied and then the force (external force) that separates the contact surface is removed, the lip portion 51c will not return to its original state by its restoring force, and there is a risk that the air discharge passage will remain open. In contrast, when the lip portion 51c separates from the contact surface pressing against the housing 5, the air discharge passage 61 opens, and the deformation that allows fluid to be ejected from both axial ends of the housing 5 is due to elastic deformation. When the force (external force) that causes this deformation is removed, the lip portion 51c returns to its original state due to its restoring force, thus closing the air discharge passage 61. For this reason, when the deformation suppression member 55 is fitted into the circumferential groove 51b of the seal member 51, it restricts deformation that does not return to the original shape due to plastic deformation, etc., and allows deformation due to elastic deformation. The deformation suppression member 55 consists of a ring body 55a and a sub-part 55b connected to the inner end surface on the outer diameter side of the ring body 55a, with the inner diameter portion of the ring body 55a fitting into the circumferential groove 51b. For this reason, the outer shape of the inner diameter portion of the ring body 55a is the same shape as the inner shape of the circumferential groove 51b. Furthermore, the deformation-suppressing member 55 is fixed to the lid member 5b via a fastener 56. In this case, the fastener 56 consists of a screw member 58 that is inserted through a through hole 57 provided in the lid member 5b. The male threaded tip 58a of the screw member 58 is screwed into the screw hole 59 of the deformation-suppressing member 55, and the head 58b of the screw member 58 fits into a recess 57a provided in the opening of the through hole 57, thereby fixing the deformation-suppressing member 55 to the lid member 5b. As a result, the deformation-suppressing member 55 receives the portion of the lip portion 51c that is omitted from the tip. Note that a space 60a is provided on the inner diameter side of the lip portion 51c through which fluid from the space 34 flows in.

[0050] A ring-shaped groove 53 is formed on the inner surface of the lid member 5c, and the main body portion 52a of the sealing member 52 is fitted into this groove 53, so that the lip portion 52c is in close contact or in contact with the cylindrical body 5a. The contact area of ​​the lip portion 52c is the contact surface 35b1, which is the bottom surface of the small diameter portion 35b on the inner side of the circumferential notch portion 35 of the cylindrical body 5a. The lip portion 52c is also inclined at a predetermined angle with respect to the axial direction of the housing. In this case, the inclination angle θ2 is set to, for example, 50° to 60°. The tip of the lip portion 52c is an annular end surface 52c1 that makes surface contact with the contact surface 35b1 of the cylindrical body 5a.

[0051] Furthermore, a deformation suppression member 55 is fitted to the circumferential groove 52b of the sealing member 52, receiving the lip portion 52c and suppressing deformation from the contact surface when the rotating shaft rotates. Here, deformation refers to deformation due to damage or deformation that does not return to its original shape due to plastic deformation. In other words, in the absence of the deformation suppression member 55, if a force (external force) that separates the contact surface is applied and then the force (external force) that separates the surface is removed, the lip portion 52c will not return to its original state by its restoring force, and there is a risk that the air discharge passage will remain open. In contrast, the deformation that occurs when the lip portion 52c separates from the contact surface that is pressed against the housing 5, causing the air discharge passage 61 to open and allowing fluid to be ejected from both axial ends of the housing 5 is deformation due to elastic deformation, and once the force (external force) that causes this deformation is removed, the lip portion 52c will return to its original state by its restoring force, thus blocking the air discharge passage 62. Therefore, when the deformation suppressing member 55 is fitted into the circumferential groove 52b of the sealing member 52, deformation that does not return to the original shape due to plastic deformation, etc., is restricted, while deformation due to elastic deformation is permitted. The deformation suppressing member 55 consists of a ring body 55a and a sub-part 55b connected to the inner end face of the outer diameter side of the ring body 55a, with the inner diameter portion of the ring body 55a fitting into the circumferential groove 52b. For this reason, the outer shape of the inner diameter portion of the ring body 55a is the same shape as the inner shape of the circumferential groove 52b. The deformation suppressing member 55 is also fixed to the lid member 5c via a fastener 56. In this case, the fixing device 56 consists of a screw member 58 inserted through a through hole 57 provided in the lid member 5b. The male threaded tip 58a of this screw member is screwed into the threaded hole of the deformation suppressing member 55, and the head 58b of the screw member 58 fits into a recess 57a provided in the opening of the through hole 57, thereby fixing the deformation suppressing member 55 to the lid member 5c. As a result, the deformation suppressing member 55 receives the portion of the lip portion 52c that omits the tip. A space 60b into which fluid from the space 39 flows is provided on the inner diameter side of the lip portion 52c. For this reason, a communication hole 40 is provided between the space 60b and the space 39.

[0052] By the way, the sealing members 51 and 52 seal the air discharge passages 61 and 62 for fluid ejection, which are provided at both axial ends of the housing 5. In this case, the air discharge passage 61 for fluid ejection is formed in the range from the sealing member 51, the deformation suppressing member 55, the inner flange portion 32, the outer diameter side of the inner flange portion 32, and the outer diameter end of the lid member 5b, and is formed in the gap between the axial inner diameter surface 30a1 of the large diameter portion 30a of the circumferential notch portion 30 and the radial end surface 30b2 of the small diameter portion 30b of the circumferential notch portion 30.

[0053] In this case, the air discharge passage 62 for fluid ejection is formed in the range from the sealing member 52, the deformation suppressing member 55, the inner flange portion 37, the outer diameter side of the inner flange portion 37, and the outer diameter end of the lid member 5c, by the gap formed between the axial inner diameter surface 35a1 of the large diameter portion 35a of the circumferential notch portion 33 and the radial end surface 35b2 of the small diameter portion 35b of the circumferential notch portion 35.

[0054] In a spindle device, when the rotating shaft is stationary or rotating at a low speed, the lip portion presses against a contact surface provided on the housing, sealing the space between the rotating shaft at the front end of the device and the housing. When the rotating shaft exceeds a predetermined rotational speed, the centrifugal force associated with the rotating shaft causes the lip portion to separate from the contact surface, releasing the seal. Therefore, a low rotational speed of the rotating shaft refers to a rotational speed at which the lip portion does not separate from the contact surface. The predetermined rotational speed is a speed that exceeds the low speed, at which the lip portion separates from the contact surface. An example of a rotational speed above the predetermined speed is 5000 min. -1 That concludes the explanation. Furthermore, deformation refers to deformation caused by damage or plastic deformation that does not restore the original shape, etc.

[0055] By the way, if a machining tool (for example, a grinding wheel or cutting tool) is attached to the tip of the rotating shaft of the spindle device shown in Figures 1 and 2, it will constitute a turning device or a cutting device. In this case, with no fluid (compressed air) supplied to the outer diameter side flow path 6 of the housing 5 or the inner diameter side flow path 7 of the rotating shaft 1, the air discharge passages 61 and 62 for fluid ejection are sealed by the respective sealing members 51 and 52, so that foreign matter can not enter the device.

[0056] Furthermore, when the rotating shaft 1 is driven to rotate, fluid (compressed air) is supplied to the outer diameter side circulation path 6 of the housing 5 and the inner diameter side circulation path 7 of the rotating shaft 1. In this case, the fluid that enters the rotating shaft 1 and the housing 5 flows into the space sections 60a and 60b via spaces 34 and 39. The fluid that enters the space sections 60a and 60b pushes up the lip sections 51c and 52c. Also, as the rotating shaft 1 rotates, centrifugal force pushes up the tips of the lip sections 51c and 52c, acting as a force that separates the tips of the lip sections 51c and 52c from the contact surface. This separation is due to deformation by elastic deformation, and when this deformation force is released, the restoring force of the lip sections 51c and 52c returns them to their original state, and the lip sections 51c and 52c come into contact with the contact surfaces 30b1 and 35b1, blocking the air discharge passages 61 and 62.

[0057] Therefore, the lip portions 51c and 52c are separated from the tip portion from the contact surface, the sealing members 51 and 52 are in an open state, and the fluid that enters the space portions 60a and 60b flows through the air discharge passages 61 and 62 and is ejected outside the device from the nozzles of the air discharge passages 61 and 62. In this case, since the nozzle of the air discharge passage 61 opens outward along the axial direction of the rotation axis, the fluid that enters the air discharge passage 61 is ejected axially forward of the housing 5, and the fluid that enters the air discharge passage 62 is ejected axially rearward of the housing 5.

[0058] Therefore, when the rotating shaft 1 is rotating, the fluid is ejected outward, which prevents foreign matter from entering the device.

[0059] In the spindle device according to the present invention, the air discharge passages 61 and 62 are blocked when the rotating shaft is stationary, so it is possible to prevent foreign matter such as processing fluid and chips from entering the sealing device. Furthermore, even when the rotating shaft is rotating, the fluid is ejected from both axial ends of the housing 5, so it is possible to prevent foreign matter from entering the sealing device even in this state. In addition, since the deformation suppression members 55, 55 are fitted into the circumferential grooves 51b, 52b of the sealing members 51 and 52, the lip portions 51c, 52c do not deform (deformation that does not return to the original shape due to plastic deformation, etc.). That is, in the absence of the deformation suppression member 55, if a force (external force) acting to separate the contact surface causes deformation, even if the force (external force) causing the deformation is removed, the lip portions 51c, 52c will not return to their original state due to their restoring force, and there is a risk that the air discharge passages 61 and 62 will remain open. Therefore, when the deformation suppressing member 55 is fitted into the circumferential grooves 51b and 52b of the sealing members 51 and 52, deformation (deformation that does not return to the original shape due to plastic deformation, etc.) is restricted, while deformation due to elastic deformation is permitted.

[0060] The present invention prevents foreign matter from entering the sealing device whether the rotating shaft is rotating or not, thereby preventing the device from being shortened due to foreign matter entering the device. Furthermore, since the lip portions 51c and 52c do not deform (deformation that does not return to its original shape due to plastic deformation, etc.), the lifespan of the sealing members 51 and 52 can be extended. In particular, when rotating, the lip portions 51c and 52c are separated from the lip contact surface of the mating side, eliminating frictional resistance caused by contact or pressure contact, suppressing heat generation in the rotating part (rotating shaft side) and the fixed part (housing side), and effectively preventing premature failure of bearings, etc., due to temperature rise of components inside the device (for example, bearings that rotatably support the rotating shaft). Moreover, when the rotating shaft 1 is stopped, there is no need to eject fluid such as compressed air, so the amount of fluid such as compressed air consumed can be reduced, contributing to cost reduction.

[0061] The deformation suppressing member 55 can be configured to be attached to the rotating shaft side and fixed via a fastener 58 to the cover members 5b and 5c that close the axial end opening of the housing 5. By configuring it in this way, the deformation suppressing member 55 can be stably fixed to the cover members 5b and 5c, and its function as a deformation suppressing member (deformation suppression function) can be effectively exercised.

[0062] Next, Figure 5 shows another embodiment (second spindle device), in which case it includes a means M for introducing air (compressed air) into the housing 5. In this case, the introduction means M is configured by making the lid members 5b and 5c into an impeller structure (centrifugal impellers 65, 66) as shown in Figures 6A, 6B, 7A, and 7B. The centrifugal impellers 65, 66 are equipped with a number of curved blades 65a, 66a.

[0063] In other words, each lid member 5b, 5c rotates in conjunction with the rotation of the rotating shaft 1, and this rotation introduces air into the housing 5 from the rear end openings of the injection passage 6b and the main flow section 7a. The other configurations are the same as those of the housing 5 shown in Figure 1, and in Figure 5, components identical to those in Figure 1 are given the same reference numerals and their descriptions are omitted.

[0064] Therefore, the spindle device shown in Figure 5 produces the same effects and functions as the spindle device shown in Figure 1.

[0065] Next, Figure 8 shows another embodiment (third spindle device), in which case the introduction means M is composed of a fan device 70 on the rotating shaft 1. In this case, the rear cover member 5c of the housing 5 is integrated with the cylindrical body 5a of the housing 5 and does not rotate with the rotation of the rotating shaft 1. For this reason, this cover member 5c is made of a flat disc-shaped body with an axial hole 5c1 and is fixed to the rear opening of the cylindrical body 5a of the housing 5 so as to close the rear opening.

[0066] Therefore, a power transmission mechanism 4, which can be composed of a gear mechanism, a belt mechanism, or a coupling mechanism, is arranged inside the housing 5. The fan device 70 is attached to the rotating shaft 1 at the rear end of the power transmission mechanism 4. For this reason, this spindle device does not have an air discharge passage 62 with a sealing device on the rear side of the housing 5, and air is not discharged from the rear of the housing 5. The fan device of the spindle device shown in Figure 8 is a centrifugal impeller 71 equipped with a number of curved blades 71a, as shown in Figure 9.

[0067] Furthermore, this spindle device is also provided with an outer diameter passage 6 and an inner diameter passage 7. The outer diameter passage 6 includes a rear-side axial first passage 75a, a first radial passage 75b extending radially inward from the tip of the axial first passage 75a, an outer diameter spiral passage 75c extending from the inner diameter end of the first radial passage 75b toward the tip, a second radial passage 75d extending radially outward from the tip of the outer diameter spiral passage 75c, a second axial passage 75e extending forward from the outer diameter end of the second radial passage 75d, and a second axial passage The passage 75e includes a third radial passage 75f extending radially inward from its tip, an outer diameter spiral passage 75g extending from the inner diameter end of the third radial passage 75f toward the tip, a fourth radial passage 75h extending radially outward from the tip of the outer diameter spiral passage 75g, a third axial passage 75i extending from the outer diameter end of the fourth radial passage 75h toward the tip, and a fifth radial passage 75j extending radially inward from the tip of the third axial passage 75i. The fifth radial passage 75j is connected to space 34.

[0068] The outer diameter side helical passage 75g is composed of a helical groove 44a provided at the tip of the inner circumferential surface of the housing 5, and the outer diameter surfaces of the outer rings 2a2, 2b2 of the bearings 2a, 2bb and the spacer 42a. Furthermore, the rear end edge of the outer diameter side helical passage 71g is connected to the third radial passage 75f, and the front end edge of the outer diameter side helical passage 75g is connected to the fourth radial passage 75h.

[0069] The outer diameter side helical passage 75c on the rear end is composed of a helical groove 44b provided at the rear end of the inner circumferential surface of the housing 5, and the outer diameter surfaces of the outer rings 3a2 and 3b2 of the bearings 3a and 3b and the spacer 42b. Furthermore, the rear end edge of the outer diameter side helical passage 75c is connected to the first radial passage 75b, and the front end edge of the outer diameter side helical passage 75c is connected to the second radial passage 75d.

[0070] The inner diameter passage 7 includes a first radial passage 76a extending radially inward from the outer surface of the rotating shaft at the rear end of the rotating shaft 1 (forward of the power transmission mechanism 4), a first axial passage 76b extending axially along the axis of the rotating shaft 1 from the inner diameter end of the first radial passage 76a, a second radial passage 76c extending radially outward from the tip of the first axial passage 76b, an inner diameter spiral-shaped passage 76d extending forward from the outer diameter end of the second radial passage 76c, and an inner diameter spiral The structure includes a third radial passage 76e extending radially inward from the tip of the shaped passage 76d, a second axial passage 76f extending axially along the rotation axis 1 from the inner diameter end of the third radial passage 76e, a fourth radial passage 76g extending radially outward from the tip of the second axial passage 76f, an inner diameter side helical passage 76h extending toward the tip from the outer diameter end of the fourth radial passage 76g, and a fifth radial passage 76i extending radially outward from the tip of the inner diameter side helical passage 76h. The fifth radial passage 76i is connected to the space 34 via the hole 33a of the spacer 33.

[0071] In other words, as the rotating shaft 1 rotates and the fan device 70 rotates, air is drawn into the housing 5 through the axial hole 5c1 of the lid member 5b and flows into the space 34 via the outer diameter passage 6 and the inner diameter passage 7. The air that flows into the space 34 then enters the air discharge passage 61 which has a sealing device. The air flows into the inner diameter passage 7 through a through hole 80 provided in the pulley or the like of the power transmission mechanism 4.

[0072] The spindle apparatus shown in Figure 8 is similar to the spindle apparatus shown in Figures 1 and 5 in other respects. In Figure 8, components identical to those in Figure 1 are denoted by the same reference numerals, and their descriptions are omitted.

[0073] The spindle device shown in Figure 8 does not have the function of injecting air from the rear, but it has the same effects as the spindle device shown in Figure 1.

[0074] In the spindle device shown in Figure 10, an axial flow impeller 72 as shown in Figure 11 is used in the fan device. The axial flow impeller 72 is an impeller in which the blades 72a are twisted, as shown in Figure 11. Even with such an axial flow impeller 72, as the rotating shaft 1 rotates and the fan device 70 rotates, air is drawn into the housing 5 through the axial hole 5c1 of the cover member 5c and flows into the space 34 via the outer diameter passage 6 and the inner diameter passage 7. The air that flows into the space 34 then enters the air discharge passage 61 which has a sealing device.

[0075] The spindle device shown in Figure 10 has the same configuration as the spindle device shown in Figure 8, and in Figure 10, components identical to those in Figure 8 are denoted by the same reference numerals, and their descriptions are omitted. Therefore, the spindle device shown in Figure 10 has the same effects and functions as the spindle device shown in Figure 8.

[0076] In the spindle device shown in Figure 12, a mixed-flow impeller 73 as shown in Figure 13 is used in the fan device. It is equipped with blades 73a such that the flow path is inclined at a constant angle with respect to the rotation axis. Even with such a mixed-flow impeller 73, as the rotation axis 1 rotates and the fan device 70 rotates, air is drawn into the housing 5 through the axial hole 5c1 of the cover member 5b and flows into the space 34 via the outer diameter passage path 6 and the inner diameter passage path 7. The air that flows into the space 34 then enters the air discharge passage 61 which has a sealing device.

[0077] The spindle device shown in Figure 12 has the same configuration as the spindle devices shown in Figures 8 and 10, and in Figure 12, components identical to those in Figures 8 and 10 are denoted by the same reference numerals, and their descriptions are omitted. Therefore, the spindle device shown in Figure 12 has the same effects and functions as the spindle devices shown in Figures 8 and 10.

[0078] Even with the spindle devices shown in Figures 5, 8, 10, and 12, a grinding device can be constructed by attaching a grinding wheel or the like as a processing tool to the tip of the rotating shaft. Whether the rotating shaft 1 is stopped or rotating, foreign matter can be prevented from entering the air discharge passage, thus preventing foreign matter from entering the grinding device.

[0079] Furthermore, even with the spindle devices shown in Figures 5, 8, 10, and 12, a cutting machine can be constructed by attaching the cutting tool of the processing tool to the tip of the rotating shaft. This prevents foreign matter from entering the air discharge passage whether the rotating shaft 1 is stopped or rotating, thus avoiding the inflow of foreign matter into the cutting machine.

[0080] Incidentally, in systems that do not use compressed air, there is no need to maintain a high air pressure within the device, thus reducing air consumption. This reduces power consumption and contributes to a lower environmental impact.

[0081] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. In the above embodiments, when the lip portion separates from the contact surface in which it is pressed against the housing, it is due to centrifugal force and fluid pressure, but it may separate due to only one of the centrifugal force and fluid pressure. That is, there are three cases: when both centrifugal force and fluid pressure are used, when only centrifugal force is used, and when only fluid pressure is used. Also, in the embodiments, the fluid ejected from the housing was from both axial ends, but it may be from only one axial end of the housing, when only the other axial end of the housing, or when it is ejected from both axial ends. Furthermore, the fluid may be supplied even while the rotating shaft 1 is rotating. Also, the fluid may be a gas or a liquid, and is not limited to compressed air as in the embodiments, but may be a cleaning fluid or a cooling medium, etc. Incidentally, a so-called V-ring was used as the sealing member, but there are A-type, S-type, L-type, and E-type V-rings, and any type can be used. Furthermore, the materials used can include nitrile rubber (NBR), fluororubber (FPM), chloroprene rubber (CR), ethylene propylene rubber (EPDM), ethylene acrylic rubber (EACM), and silicone rubber (Q).

[0082] A spindle device comprises a rotating part supported by bearings and a stationary part other than the rotating part. Grinding wheels, cutting tools, etc., are mounted on the tip of the rotating part.

[0083] 1. Rotating shaft 2. Bearing 3. Bearing 5. Housing 6. Outer diameter passage 7. Inner diameter flow path 7A2, 7B2. Helical passage 51, 52. Sealing device (sealing member) 51c, 52c. Lip section 61, 62. Air discharge passage 70. Fan device 75c, 75g, 76d. Helical passage

Claims

1. A spindle device comprising a rotating shaft capable of mounting an object at its tip, a housing that rotatably supports the rotating shaft via a bearing, and a sealing device disposed between the rotating shaft at the tip of the device and the housing, wherein the sealing device has a lip portion that presses against a contact surface provided on the housing when the rotating shaft is stationary or rotating at a low speed, thereby sealing the space between the rotating shaft at the tip of the device and the housing, and when the rotating shaft rotates at a predetermined rotational speed exceeding the low speed, the centrifugal force associated with the rotating shaft causes the lip portion to separate from the contact surface, thereby releasing the seal, and also includes a deformation suppressing member that limits the deformation of the lip portion when the rotating shaft rotates, Furthermore, the spindle device is characterized in that the housing is provided with an outer diameter side passage through which air drawn into the device from the outside flows inside the device, an outer diameter side spiral passage is provided on the outer diameter side of the bearing that rotatably supports the rotating shaft in the outer diameter side passage, an air discharge passage for discharging air from at least the tip side of the device is connected to the outer diameter side passage, the seal device is arranged in the air discharge passage, and when the lip portion of the seal device separates from the contact surface, the air pressure of the air that has flowed through the outer diameter side passage acts in addition to the centrifugal force when the rotating shaft rotates.

2. A spindle device comprising a rotating shaft capable of mounting an object at its tip, a housing that rotatably supports the rotating shaft via a bearing, and a sealing device disposed between the rotating shaft at the tip of the device and the housing, wherein the sealing device has a lip portion that presses against a contact surface provided on the housing when the rotating shaft is stationary or rotating at a low speed, thereby sealing the space between the rotating shaft at the tip of the device and the housing, and when the rotating shaft rotates at a predetermined rotational speed exceeding the low speed, the centrifugal force associated with the rotating shaft causes the lip portion to separate from the contact surface, thereby releasing the seal, and also includes a deformation suppressing member that limits the deformation of the lip portion when the rotating shaft rotates, Furthermore, the spindle device is characterized in that the rotating shaft is provided with an inner diameter passage through which air drawn into the device from the outside flows inside the device, an inner diameter spiral passage is provided on the inner diameter side of the bearing that rotatably supports the rotating shaft in the inner diameter passage, an air discharge passage for discharging air from at least the tip side of the device is connected to the inner diameter passage, the sealing device is arranged in the air discharge passage, and when the lip portion of the sealing device separates from the contact surface, the air pressure of the air that has flowed through the inner diameter passage acts in addition to the centrifugal force during the rotation of the rotating shaft.

3. A spindle device comprising a rotating shaft capable of mounting an object at its tip, a housing that rotatably supports the rotating shaft via a bearing, and a sealing device disposed between the rotating shaft at the tip of the device and the housing, wherein the sealing device has a lip portion that presses against a contact surface provided on the housing when the rotating shaft is stationary or rotating at a low speed, thereby sealing the space between the rotating shaft at the tip of the device and the housing, and when the rotating shaft rotates at a predetermined rotational speed exceeding the low speed, the centrifugal force associated with the rotating shaft causes the lip portion to separate from the contact surface, thereby releasing the seal, and also includes a deformation suppressing member that limits the deformation of the lip portion when the rotating shaft rotates. Furthermore, the spindle device is characterized in that the housing is provided with an outer diameter passage for air drawn into the device from the outside to flow through the device, and an outer diameter spiral passage is provided on the outer diameter side of the bearing that rotatably supports the rotating shaft in the outer diameter passage, and the rotating shaft is provided with an inner diameter passage for air drawn into the device to flow through the device, and an inner diameter spiral passage is provided on the inner diameter side of the bearing that rotatably supports the rotating shaft in the inner diameter passage, and an air discharge passage for discharging air from at least the tip side of the device is connected to the outer diameter passage and the inner diameter passage, and the sealing device is arranged in the air discharge passage, and when the lip portion of the sealing device separates from the contact surface, the air pressure of the air that has flowed through the outer diameter passage and the inner diameter passage acts in addition to the centrifugal force when the rotating shaft rotates.

4. The spindle device according to claim 1, characterized in that an air discharge passage for discharging air from the rear end of the device is connected to the outer diameter side passage, the sealing device is arranged in the air discharge passage, and when the lip portion of the sealing device separates from the contact surface, the air pressure of the air flowing through the outer diameter side passage acts in addition to the centrifugal force during the rotation of the rotating shaft.

5. The spindle device according to claim 2, wherein an air discharge passage for discharging air from the rear end of the device is connected to the inner diameter passage, and the sealing device is arranged in the air discharge passage, and when the lip portion of the sealing device separates from the contact surface, the air pressure of the air flowing through the inner diameter passage acts in addition to the centrifugal force during the rotation of the rotating shaft.

6. The spindle device according to claim 3, characterized in that an air discharge passage for discharging air from the rear end of the device is connected to the outer diameter side passage and the inner diameter side passage, respectively.

7. The spindle device according to any one of claims 1 to 3, further comprising a fan device that rotates in conjunction with the rotation of the rotating shaft to draw air from the outside into the device.

8. A grinding apparatus comprising the spindle device described in claims 1 to 3, characterized in that the object mounted on the tip of the rotating shaft is a grinding wheel.

9. A cutting machine comprising the spindle device described in claims 1 to 3, characterized in that the mounted object attached to the tip of the rotating shaft is a cutting tool.

Images