Spindle device, grinding device, and cutting device

Abstract

This effectively prevents a reduction in the lifespan of sealing components due to abnormal wear. [Solution] 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 front end of the device and the housing. When the rotating shaft exceeds a predetermined rotational speed beyond low speed, the centrifugal force associated with the rotating shaft causes the lip portion to separate from the contact surface, releasing the seal. A deformation suppression member is provided to limit 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, and the housing is provided with an outer diameter side passage through which the air drawn in from the outside into the device 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, 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 acts in addition to the centrifugal force when the rotating shaft rotates.

Description

Technical Field

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

Background Art

[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 a bearing 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 (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 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 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 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] Furthermore, conventionally, there are cutting devices that have an air seal exhaust passage 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 air pressure. 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. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2007-223008 [Patent Document 2] Japanese Patent Publication No. 2005-59151 [Patent Document 3] Patent No. 3745584 [Overview of the project] [Problems that the invention aims to solve]

[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. [Means for solving the problem]

[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 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 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, 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 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 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 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. 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. -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 lid member that closes the axial opening of the housing is provided on the rotating shaft, and blades that suck external air and pump the air into the housing are provided on the lid member. Thus, as the rotating shaft rotates, the lid member rotates, and air can be sucked into the device from the outside. As a result, there is no need to introduce air from outside the housing, and external air can be stably sucked into the device. That is, since there is no need to increase the air pressure inside the device, the air consumption can be reduced.

[0020] In the first spindle device, an air discharge path for discharging air from the rear end side of the device communicates with the outer diameter side passage path, and the seal device is arranged in the air discharge path. When the lip portion of the seal device is separated from the contact surface, in addition to the centrifugal force during the rotation of the rotating shaft, the air pressure of the air flowing through the outer diameter side passage path can be configured to act.

[0021] In the second spindle device, an air discharge path for discharging air from the rear end side of the device communicates with the inner diameter side passage path, and the seal device is arranged in the air discharge path. When the lip portion of the seal device is separated from the contact surface, in addition to the centrifugal force during the rotation of the rotating shaft, the air pressure of the air flowing through the inner diameter side passage path can be configured to act.

[0022] Thus, in the case of having an air discharge path for discharging air from both the front end side and the rear end side of the device, it is possible to prevent the intrusion of foreign matter into the seal device whether the rotating shaft is rotating or not, and it is possible to prevent the shortening of the device life due to the intrusion of foreign matter into the device.

[0023] The grinding device according to the present invention is a grinding device provided with the spindle device, and the object mounted on the tip of the rotating shaft is a grinding wheel. In the grinding device according to the present invention, even when the rotating shaft is stopped or rotating, the air discharge path can prevent the inflow of foreign matter and avoid the inflow of foreign matter into the grinding device.

[0024] The cutting device according to the present invention is a cutting device provided with the spindle device, and the mounted object attached to the tip of the rotating shaft is a cutting tool. In the cutting device according to the present invention, even when the rotating shaft is stopped or rotating, the air discharge path can prevent the inflow of foreign matter and avoid the inflow of foreign matter into the cutting device.

Effect of the Invention

[0025] The present invention can prevent foreign matter from entering the seal device whether the rotating shaft is rotating or not, and can prevent the shortening of the device life due to the entry of foreign matter into the device. In addition, the deformation of the lip portion (deformation that cannot be restored to the original shape due to plastic deformation or the like) can be suppressed, so that the long life of the seal member can be achieved. In particular, during rotation, the lip portion will be separated from the mating lip contact surface (the separation in this case is due to elastic deformation), and there is no frictional resistance caused by contact or pressure contact, so the heat generation of the rotating part (rotating shaft side) and the fixed part (housing side) is suppressed, and the early breakage of bearings and the like due to the temperature rise of the members in the device (for example, bearings that support the rotating shaft rotatably) can be effectively prevented. Furthermore, when the rotating shaft is stopped, since the ejection of fluids such as compressed air is not required, the consumption of fluids such as compressed air can be suppressed, contributing to cost reduction. Moreover, as the lid member rotates with the rotation of the rotating shaft and air can be inhaled from the outside into the device, the consumption of air can be reduced, the power consumption can be reduced, and the environmental load can be reduced.

Brief Description of the Drawings

[0026] [Figure 1] It is a cross-sectional view of the spindle device according to the present invention. [Figure 2] It is an enlarged cross-sectional view showing the flow of air inhaled into the spindle device. [Figure 3] The rear lid member is shown, (a) is a simplified view seen from the rear of the spindle device, and (b) is a half perspective view. [Figure 4] The front lid member is shown, which is a simplified view seen from the front of the spindle device, and (b) is a half perspective view. [Figure 5] The front sealing device is shown; (a) is an enlarged cross-sectional view with the rotating shaft not rotating, and (b) is an enlarged cross-sectional view with the rotating shaft rotating. [Figure 6] The rear sealing device is shown; (a) is an enlarged cross-sectional view with the rotating shaft not rotating, and (b) is an enlarged cross-sectional view with the rotating shaft rotating. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described below with reference to Figures 1 to 6. 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, processing (polishing, cutting, etc.) is performed on the workpiece using these processing tools.

[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 inward 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 3(a) and 4(a) and 4(b). 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 rotation axis 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 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] Furthermore, as shown in Figures 5 and 6, sealing members 51 and 52 are attached to each lid member 5b and 5c as sealing devices. The sealing members 51 and 52 consist of a main body portion 51a and 52a made of a ring member, and a ring-shaped lip portion 51c and 52c connected to the main body portion 51a and 52a via circumferential grooves 51b and 52b. In other words, so-called V-rings are used as the sealing members 51 and 52 in this case.

[0043] In this case, as shown in Figure 5, 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 side of the housing. 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 of the housing. 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 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, etc. 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, and the air discharge passage 61 becomes open, allowing fluid to be ejected from both axial ends of the housing 5, is deformation due to elastic deformation, and when 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 blocking 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 Figure 6, 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 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 become open. In contrast, the deformation when the lip portion 52c separates from the contact surface that is pressed against the housing 5, and the air discharge passage 62 becomes open, allowing the fluid to be ejected from both axial ends of the housing 5, is deformation due to elastic deformation, and when the force (external force) that causes this deformation is removed, the lip portion 52c will return to its original state by its restoring force, 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 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 by the gap between the bottom of the notch 30 and the outer diameter end face of the notch 30, in the range of the sealing member 51, the deformation suppressing member 55, the inner flange 32, the outer diameter side of the inner flange 32, and the outer diameter end of the lid member 5b.

[0048] In this case, the air discharge passage 62 for fluid ejection is formed by the gap between the bottom of the notch 35 and the outer diameter end face of the notch 35, in the range of 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.

[0049] Incidentally, 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, since no fluid is supplied (no air is pumped) to the outer diameter passage 6 of the housing 5 or the inner diameter passage 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.

[0050] Furthermore, when the rotating shaft 1 is driven to rotate, the lid members 5b and 5c rotate, drawing air into the housing 5, which is then supplied to the outer diameter passage 6 of the housing 5 and the inner diameter passage 7 of the rotating shaft 1. In this case, the fluid entering the rotating shaft 1 and the housing 5 flows into the spaces 60a and 60b via spaces 34 and 39. The fluid entering the spaces 60a and 60b pushes up the lip portions 51c and 52c. Also, as the rotating shaft 1 rotates, centrifugal force pushes up the tips of the lip portions 51c and 52c, acting to separate them from the contact surface. This separation is due to elastic deformation, and when this deformation force is released, the restoring force of the lip portions 51c and 52c returns them to their original state, causing them to contact the contact surfaces 30b1 and 35b1 and block the air discharge passages 61 and 62.

[0051] As a result, 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. -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 foreign matter entering the device. 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, 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, it is not necessary to eject fluid such as compressed air, so the amount of fluid such as compressed air consumed can be reduced, 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 in conjunction with the rotation of the rotating shaft 1, 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 minimized.

[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 also 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 also be from only one axial end of the housing, when only the other axial end of the housing, or 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 also be a cleaning fluid or a cooling medium. By the way, a so-called V-ring was used as the sealing member, but V-rings include A-type and S-type. It comes in three types: P, L, and E, and any type can be used. The materials can include nitrile rubber (NBR), fluororubber (FPM), chloroprene rubber (CR), ethylene propylene rubber (EPDM), ethylene acrylic rubber (EACM), and silicone rubber (Q). [Explanation of symbols]

[0058] 1. Axis of rotation 2 bearings 3 Bearings 5 Housing 5b, 5c Lid members 6. Outer diameter passage path 7. Inner diameter passage path 51, 52 Sealing device (sealing member) 51c, 52c Lip section 61, 62 Air discharge channel 65a, 66a blades

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 cover 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, The sealing device includes a deformation-restricting member that, when the rotating shaft is stationary or rotating at a low speed, presses the lip portion 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 above 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 restricts 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 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 cover 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, The sealing device includes a deformation-restricting member that, when the rotating shaft is stationary or rotating at a low speed, presses the lip portion 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 above 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 restricts 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. 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 cover 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, The sealing device includes a deformation-restricting member that, when the rotating shaft is stationary or rotating at a low speed, presses the lip portion 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 above 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 restricts 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. A spindle device characterized in that 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, wherein 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 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 inner diameter side 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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