Spindle device, grinding device, and cutting device

Abstract

According to the present invention, while a rotating shaft is stationary or rotating at a low speed, a lip portion is in pressure contact with a contact surface provided on a housing, forming a seal between the rotating shaft on a device tip side and the housing, and when the rotating shaft is at or above a predetermined rotational speed exceeding the low-speed rotation, the lip portion separates from the contact surface as a result of a centrifugal force associated with the rotating shaft, thereby releasing the seal. A deformation suppressing member is provided to limit deformation of the lip portion during the rotation of the rotating shaft. A lid member is provided with a blade for sucking in external air and feeding the air into the housing under pressure, and the housing is provided with an outer diameter-side passage path through which the air sucked into the device from the outside by the rotation of the lid member flows through the device. An air discharge path for discharging air at least from the tip end side of the device communicates with the outer diameter-side passage path, and a sealing device is disposed in the air discharge path. 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 path acts in addition to the centrifugal force during the rotation of the rotating shaft.

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. And, various machining tools (for example, grindstones, cutting tools, etc.) are attached to the tip of the rotating shaft that constitutes the rotating part, and machining (grinding, cutting, etc.) is performed on the workpiece with these machining tools.

[0003] Therefore, there has been a risk that foreign substances such as machining fluid and chips may enter the spindle device from the gap between the rotating part and the fixed part during machining. If foreign substances enter 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 structure in which an air chamber is provided in the housing and 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 is configured to separate the lip 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] In Patent Documents 1, 2, and 3, the air supply port of the air supply passage inside the housing communicates with an air supply means provided outside the housing. Specifically, in Patent Document 1, an air supply passage for introducing air into an air chamber is provided inside the housing, and the air supply passage opens on the outer surface of the housing. This opening serves as the air supply port, and air is supplied from an air supply device outside the housing. In Patent Document 2, the air supply passage opens at the rear end of the housing, and air is supplied from an air supply means outside the housing. Furthermore, in Patent Document 3, a passage for introducing air is formed in the casing (housing), and this passage communicates with the outside via a hose or the like. Therefore, air is introduced into the housing from the outside via the passage. When compressed air is introduced into the housing from the outside in this way, there is a problem that energy loss increases.

[0012] Incidentally, by installing a contact seal in the gap between the rotating and stationary parts of the spindle device, it is possible to effectively prevent the intrusion of processing fluids and chips into the device. When installed in devices with relatively high rotational speeds, such as spindle devices, contact seals are generally installed in the stationary part of the spindle device. The contact seal installed in the stationary part physically eliminates the gap, preventing the intrusion of processing fluids and chips into the spindle device, thus eliminating the need to use compressed air as described above. However, the frictional resistance of the contact seal hinders the smooth rotational movement of the rotating part, and the increased rotational torque increases the power consumption required to rotate the spindle device. Furthermore, the frictional resistance of the contact seal generates heat in the rotating and stationary parts, which can lead to abnormal wear of the contact seal and a reduced lifespan, as well as concerns that the heat may be transmitted to the bearings, causing abnormal temperature increases in the bearings and potentially leading to premature bearing failure.

[0013] Therefore, the present invention provides a spindle device, a grinding device, and a cutting device that can reduce power consumption and environmental impact, effectively prevent the intrusion of processing fluids and chips into the device, and effectively prevent a reduction in lifespan due to abnormal wear of sealing members.

[0014] The first spindle device of the present invention comprises a rotating shaft on which a load can be attached to its tip, a housing that rotatably supports the rotating shaft via a bearing, a lid member that closes the axial opening of the housing and rotates integrally with the rotating shaft, and a sealing device disposed between the rotating shaft and the housing on the tip side of the device, 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 and the housing on the tip side of the device, and when the rotating shaft rotates at a predetermined rotational speed above the low speed, the lip portion separates from the contact surface due to the centrifugal force associated with the rotating shaft, thereby sealing the space. The device includes a deformation suppression member that releases the seal and limits the deformation of the lip portion when the rotating shaft rotates, the lid member is provided with vanes that draw in external air and pressurize the air into the housing, the housing is provided with an outer diameter side passage through which air drawn into the device from the outside by the rotation of the lid member flows inside the device, an air discharge passage that discharges air from at least the front end of the device is connected to the outer diameter side passage, the sealing device is placed 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 side passage acts in addition to the centrifugal force when the rotating shaft rotates.

[0015] The second spindle device of the present invention is a spindle device comprising a rotating shaft on which a load can be attached to its tip, a housing that rotatably supports the rotating shaft via a bearing, a lid member that closes the axial opening of the housing and rotates integrally with the rotating shaft, 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 to seal the space between the rotating shaft on the tip side of the device and the housing, and when the rotating shaft is rotating at a predetermined rotational speed above the low speed, the lip portion separates from the contact surface due to the centrifugal force associated with the rotating shaft, and The device includes a deformation suppression member that releases the seal and limits the deformation of the lip portion when the rotating shaft rotates, the lid member is provided with vanes that draw in external air and pressurize the air into the housing, the rotating shaft is provided with an inner diameter passage through which air drawn into the device from the outside by the rotation of the lid member flows inside the device, an air discharge passage that discharges air from at least the tip side of the device is connected to the inner diameter passage, the sealing device is placed 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.

[0016] A third spindle device of the present invention comprises a rotating shaft on which an object can be mounted at its tip, a housing that rotatably supports the rotating shaft via a bearing, a lid member that closes the axial opening of the housing and rotates integrally with the rotating shaft, and a sealing device disposed between the rotating shaft and the housing on the tip side of the device, 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 and the housing on the tip side of the device, 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 the sealing device also comprises a deformation suppressing member that limits the deformation of the lip portion when the rotating shaft rotates. The lid member is provided with vanes that draw in external air and pressurize it into the housing, the housing is provided with an outer diameter passage through which air drawn in from the outside into the device by the rotation of the lid member flows inside the device, and the rotating shaft is provided with an inner diameter passage through which air drawn in from the inside into the device by the rotation of the lid member flows inside the device, and an air discharge passage that discharges 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 positioned 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.

[0017] The deformation in the first, second, and third spindle devices 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 a deformation suppression 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 open. In contrast, the deformation that occurs when the lip portion separates from the contact surface that is pressed against the housing, and the air discharge passage opens, 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 seal device is equipped with a deformation suppression member, deformation that does not return to its original shape due to plastic deformation, etc., is restricted, while deformation due to elastic deformation is permitted.

[0018] 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 or rotating at a low speed, thus preventing foreign matter such as processing fluid and chips from entering the sealing device. Note that low-speed rotation refers to rotation at a speed in which the lip portion does not separate from the contact surface. Furthermore, even when the rotating shaft is rotating at a predetermined rotational speed or higher than the low-speed rotation, the fluid is ejected from both axial ends of the housing, thus preventing foreign matter from entering the sealing device. The predetermined rotational speed is a speed exceeding the low-speed rotation, such that the lip portion separates from the contact surface. For example, the predetermined rotational speed is 5000 min. -1 The above is preferable. Furthermore, 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.

[0019] A cover member is provided on the rotating shaft to close the axial opening of the housing, and the cover member is equipped with vanes that draw in external air and pressurize the air into the housing. As the rotating shaft rotates, the cover member rotates, allowing air to be drawn into the device from the outside. This eliminates the need to introduce air from outside the housing, and allows for a stable intake of external air into the device. In other words, since there is no need to maintain a high air pressure inside the device, air consumption can be reduced.

[0020] In the first 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 acts in addition to the centrifugal force during the rotation of the rotating shaft.

[0021] In the second spindle device, 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 inner diameter passage acts in addition to the centrifugal force during the rotation of the rotating shaft.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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, it can suppress deformation of the lip portion (deformation that does not return to its original shape due to plastic deformation, etc.), thereby extending the lifespan of the sealing member. In particular, during rotation, the lip portion separates from the lip contact surface of the mating side (separation in this case is due to elastic deformation), eliminating frictional resistance caused by contact or pressure contact. This suppresses heat generation in the rotating part (rotating shaft side) and the fixed part (housing side), effectively preventing premature failure of bearings and other components inside the device (for example, bearings that rotatably support the rotating shaft) due to temperature rise. Moreover, when the rotating shaft is stopped, there is no need to eject fluids such as compressed air, thus reducing the consumption of fluids such as compressed air and contributing to cost reduction. In addition, as the lid member rotates with the rotation of the rotating shaft, air can be drawn into the device from the outside, reducing air consumption and power consumption, thereby reducing the environmental impact.

[0026] This is a cross-sectional view of the spindle device according to the present invention. This is an enlarged cross-sectional view showing the airflow drawn into the inside of the spindle device. This is a simplified view of the rear cover member as seen from the rear of the spindle device. This is a half-view perspective view of the rear cover member. This is a simplified view of the front cover member as seen from the front of the spindle device. This is a half-view perspective view of the front cover member. This is an enlarged cross-sectional view of the front seal device with the rotation shaft not rotating. This is an enlarged cross-sectional view of the front seal device with the rotation shaft rotating. This is an enlarged cross-sectional view of the rear seal device with the rotation shaft not rotating. This is an enlarged cross-sectional view of the rear seal device with the rotation shaft rotating.

[0027] Embodiments of the present invention will be described below with reference to Figures 1 to 6B. 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.

[0028] The mounting object is directly or indirectly attached to the mounting portion 1a on the reaction power transmission mechanism side (i.e., the front end) of the rotating shaft 1. The housing 5 has an outer diameter passage 6 through which fluid (air) flows, and the rotating shaft 1 has an inner diameter passage 7 through which fluid (air) flows. The housing 5 comprises a cylindrical body 5a that constitutes the housing 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 mounting object 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.

[0029] Incidentally, the outer diameter passage 6 has an intermediate passage 6a provided in the axial middle of the body of the cylindrical body 5a of the housing, 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.

[0030] The tip-side passage 6A has an axial passage 6A1 extending from the injection passage 6b toward the tip and a radial passage 6A2 extending radially toward the inner diameter from the tip of the axial passage 6A1.

[0031] The rear end passage 6B has an axial passage 6B1 extending from the injection passage 6b toward the rear end and a radial passage 6B2 extending radially inward from the rear end of the axial passage 6B1.

[0032] Furthermore, as shown in Figure 2, the front pair of bearings 2a, 2b 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.

[0033] 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 circumferential notch 30.

[0034] 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. This bearing inner ring retainer 33 is provided with a hole 33a that communicates with the radial passage 7b in front of the inner diameter side passage path 7 of the rotating shaft 1, which will be described later. 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 radial passage 6A2 of the tip side passage 6A of the outer diameter side passage path 6 communicates with the space 34.

[0035] 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 circumferential notch 35 consists of a large diameter portion 35a on the opening side and a small diameter portion 35b on the inner side, and the rear lid member 5c is rotatably fitted into the circumferential notch 35.

[0036] 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. This bearing inner ring retainer 38 is provided with a hole that constitutes the radial passage 7c behind the inner diameter side passage 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 radial passage 6B2 of the rear end side passage 6B of the outer diameter side passage path 6 communicates with the space 39.

[0037] The lid members 5b and 5c are constructed with an impeller structure (centrifugal impellers 65 and 66) as shown in Figures 3A, 3B, 4A, and 4B. The centrifugal impellers 65 and 66 are equipped with a number of curved blades 65a and 66a.

[0038] 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 injection passage 6b and the rear end opening of the main flow section 7a. In other words, the lid members 5b, 5c serve as means M for introducing air (compressed air) into the housing 5.

[0039] As shown in Figure 2, the inner diameter passage path 7 comprises a main channel 7a arranged along the axis of the rotating shaft 1, a radial passage 7b extending radially from the tip side of the main channel 7a, and a radial passage 7c extending radially from the rear end side of the main channel 7a.

[0040] The radial passage 7b is the leading-end passage on the inner diameter side of the housing 5 and communicates with the space 34 between the frontmost bearing 2a and the bearing inner ring retainer 33.

[0041] The radial passage 7c is located on the inner diameter side of the housing 5 and is at the rear end, communicating with the space 39 between the last row of bearings 3b and the bearing inner ring retainer 38.

[0042] Further, as shown in FIGS. 5A, 5B, 6A, and 6B, seal members 51 and 52 as seal devices are attached to each of the lid members 5b and 5c. The seal members 51 and 52 include 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 via circumferential concave grooves 51b and 52b. That is, in this case, the so-called V-rings are used as the seal members 51 and 52.

[0043] In this case, as shown in FIGS. 5A and 5B, a ring-shaped concave groove 53 is formed on the inner surface of the lid member 5b, and the main body portion 51a of the seal member 51 is fitted into the concave groove 53, and the lip portion 51c is in close contact or contact with the lip end portion on the side of the cylindrical body 5a of the housing. The contact portion of the lip portion 51c is a contact surface 30b1 which is the bottom surface of the small-diameter portion 30b on the back side of the circumferential notch portion 30 of the cylindrical body 5a of the housing. Further, the lip portion 51c is inclined at a predetermined angle with respect to the axial direction of the housing. In this case, the inclination angle θ is set, for example, from 50° to 60°. Further, the tip end portion of the lip portion 51c is an annular end surface 51c1 so as to be in surface contact with the contact surface 30b1 of the cylindrical body 5a of the housing.

[0044] 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 deformation from the contact surface 30b1 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 lip portion 51c is applied and then the force (external force) that separates the lip portion 51c 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, the deformation that occurs when the lip portion 51c 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 51c will return to its original state by its restoring force, thus closing the air discharge passage 61. Therefore, when the deformation suppressing member 55 is fitted into the circumferential groove 51b of the sealing member 51, 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 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. The deformation suppressing member 55 is also fixed to the lid member 5b 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 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. A space 60a is provided on the inner diameter side of the lip portion 51c through which fluid from the space 34 flows in.

[0045] As shown in Figures 6A and 6B, 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 of the housing. 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 35 of the cylindrical body 5a of the housing. 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 of the housing.

[0046] Furthermore, a deformation suppression member 55 is fitted to the circumferential groove 52b of the sealing member 52, receiving the lip portion 52c and limiting the deformation of the lip portion 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, without the deformation suppression member 55, if a force (external force) that separates the lip portion 52c from the contact surface is applied and then the force (external force) that separates the lip portion 52c 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 62 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 5c. 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.

[0047] The seal members 51 and 52 seal the air discharge paths 61 and 62 for fluid ejection provided at both axial ends of the housing 5. Here, in this case, the air discharge path 61 for fluid ejection is formed by a gap formed between the bottom of the notch portion 30 and the outer diameter end face of the notch portion 30 in the range from the seal member 51, the deformation suppressing member 55, the inner flange portion 32, the outer diameter side of the inner flange portion 32, and up to the outer diameter end of the lid member 5b.

[0048] Further, in this case, the air discharge path 62 for fluid ejection is formed by a gap formed between the bottom of the notch portion 35 and the outer diameter end face of the notch portion 35 in the range from the seal member 52, the deformation suppressing member 55, the inner flange portion 37, the outer diameter side of the inner flange portion 37, and up to the outer diameter end of the lid member 5c.

[0049] By attaching a machining tool (e.g., a grinding wheel, a cutting tool, etc.) to the tip of the rotating shaft of the spindle device shown in FIGS. 1 and 2, a turning device or a cutting device can be configured. In this case, since the air discharge paths 61 and 62 for fluid ejection are sealed by the respective seal members 51 and 52 in a state where no fluid (no air is pumped) is supplied to the outer diameter side passage 6 of the housing 5 and the inner diameter side passage 7 of the rotating shaft 1, foreign matter intrusion into the device can be prevented.

[0050] When the rotating shaft 1 is rotationally driven, air is sucked into the housing 5 as the lid members 5b and 5c rotate, and is supplied to the outer diameter side passage 6 of the housing 5 and the inner diameter side passage 7 of the rotating shaft 1. In this case, the fluid that has entered the rotating shaft 1 and the housing 5 flows into the space portions 60a and 60b through the spaces 34 and 39. The fluid that has entered the space portions 60a and 60b pushes up the lip portions 51c and 52c. Further, due to the rotation of the rotating shaft 1, a centrifugal force acts to push up the tip portions of the lip portions 51c and 52c, separating them from the contact surface. The separation here is due to deformation caused by elastic deformation, and when the force causing this deformation is released, the lip portions 51c and 52c return to their original state by the restoring force, and the lip portions 51c and 52c contact the contact surfaces 30b1 and 35b1, closing the air discharge paths 61 and 62.

[0051] 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 nozzles of the air discharge passages 61 and 62 open 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.

[0052] Therefore, when the rotating shaft 1 is rotating, the fluid is ejected outward, which prevents foreign matter from entering the device.

[0053] In the spindle device according to the present invention, the air discharge passages 61 and 62 are blocked when the rotating shaft is stationary or rotating at a low speed, thereby preventing foreign matter such as processing fluid and chips from entering the sealing device. Low-speed rotation refers to rotation at a speed in which the lip portion does not separate from the contact surface. Furthermore, when the rotating shaft is rotating at a predetermined rotational speed or higher than the low-speed rotation, the fluid is ejected from both axial ends of the housing 5, thus preventing foreign matter from entering the sealing device even in this state. The predetermined rotational speed is a speed exceeding the low-speed rotation, such that the lip portion separates from the contact surface. For example, the predetermined rotational speed is 5000 min. -1 The above is preferable. Furthermore, since the deformation suppressing members 55, 55 are fitted into the circumferential grooves 51b, 52b of the sealing members 51, 52, deformation of the lip portions 51c, 52c (deformation that does not return to its original shape due to plastic deformation, etc.) can be suppressed. In other words, in the absence of the deformation suppressing members 55, after deformation occurs due to a force (external force) acting to separate the contact surface, 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, 62 will remain open. For this reason, when the deformation suppressing members 55 are fitted into the circumferential grooves 51b, 52b of the sealing members 51, 52, deformation (deformation that does not return to its original shape due to plastic deformation, etc.) is restricted, and deformation due to elastic deformation is permitted.

[0054] 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 the intrusion of foreign matter. Furthermore, it can suppress deformation of the lip portions 51c and 52c (deformation that does not return to its original shape due to plastic deformation, etc.), thereby extending the lifespan of the sealing members 51 and 52. 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. This suppresses heat generation in the rotating part (rotating shaft side) and the fixed part (housing side), effectively preventing premature failure of bearings and other components inside the device (for example, bearings that rotatably support the rotating shaft) due to temperature rise. Moreover, when the rotating shaft 1 is stopped, it is not necessary to eject fluid such as compressed air, thus reducing the consumption of fluid such as compressed air and contributing to cost reduction.

[0055] 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.

[0056] Furthermore, by providing vanes 65a and 66a on the lid members 5b and 5c that draw in external air and pressurize it into the housing, the lid members 5b and 5c rotate as the rotating shaft 1 rotates, allowing air to be drawn into the device from the outside. This eliminates the need to introduce air from outside the housing, and allows for a stable intake of external air into the device. In other words, since there is no need to maintain a high air pressure inside the device, air consumption can be reduced, power consumption can be reduced, and the environmental impact can be reduced.

[0057] 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 was due to centrifugal force and fluid pressure, but it may separate due to only one of centrifugal force or 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), chloropum rubber (CR), ethylene propylene rubber (EPDM), ethylene acrylic rubber (EACM), and silicone rubber (Q).

[0058] 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.

[0059] 1. Rotating shaft 2. Bearing 3. Bearing 5. Housing 5b, 5c. Cover member 6. Outer diameter passage 7. Inner diameter passage 51, 52. Sealing device (sealing member) 51c, 52c. Lip portion 61, 62. Air discharge passage 65a, 66a. Blade

Claims

1. 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, a lid member that closes the axial opening of the housing and rotates integrally with the rotating shaft, 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 lip portion separates from the contact surface due to the centrifugal force associated with the rotating shaft, thereby releasing the seal, and also includes a deformation suppressing member that limits the deformation of the lip portion when the rotating shaft rotates, and the lid member is provided with vanes that draw in external air and pressurize the air into the housing. 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 by the rotation of the lid member flows inside the device, 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 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 side passage acts in addition to the centrifugal force when the rotating shaft rotates.

2. 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, a lid member that closes the axial opening of the housing and rotates integrally with the rotating shaft, 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 lip portion separates from the contact surface due to the centrifugal force associated with the rotating shaft, thereby releasing the seal, and also includes a deformation suppressing member that limits the deformation of the lip portion when the rotating shaft rotates, and the lid member is provided with vanes that draw in external air and pressurize the air into the housing. A spindle device characterized in that the rotating shaft is provided with an inner diameter passage through which air drawn into the device from the outside by the rotation of the lid member flows inside the device, 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 on which an object can be mounted at its tip, a housing that rotatably supports the rotating shaft via a bearing, a lid member that closes the axial opening of the housing and rotates integrally with the rotating shaft, 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 lip portion separates from the contact surface due to the centrifugal force associated with the rotating shaft, thereby releasing the seal, and also includes a deformation suppressing member that limits the deformation of the lip portion when the rotating shaft rotates, A spindle device characterized in that the lid member is provided with vanes for drawing in external air and pressurizing the air into the housing, the housing is provided with an outer diameter passage for air drawn into the device from the outside by the rotation of the lid member and flowing through the device, the rotating shaft is provided with an inner diameter passage for air drawn into the device by the rotation of the lid member and flowing through the device, 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, 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 during the rotation of the rotating shaft.

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. 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.

7. 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.

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