Rotating device and assembling method of rotating device

Abstract

To suppress a friction force which is generated between a rotating member or a support member and a packing while maintaining sealing performance against an external force, in a rotating device.SOLUTION: In a rotating device, either of a rotating member and a support member comprises an annular groove part for accommodating a packing, the other of the rotating member and the support member comprises a salient part which contacts with the packing while elastically deforming the packing, and annularly extends along a peripheral face of the packing, the salient part comprises a first inclination face formed at an accommodation space side of a lubricant, and a second inclination face formed at a side opposite to the accommodation space side, a contact end part has a region in which contact pressure with the packing becomes maximum, and the region in which the contact pressure becomes maximum is located at the accommodation space side with respect to a center of the contact end part in a rotation axial direction of the rotating member.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a rotation device and a method for assembling a rotation device. [Background technology]

[0002] A sealing method using an oil seal is known to prevent leakage of lubricating oil from a rotating shaft (see, for example, Patent Document 1). As shown in Fig. 1A, an oil seal 100 has a seal lip 101A formed on an annular seal body 101 that fits into a support member 120 of a rotating shaft 110, and a spring 102 presses the seal lip 101A against the rotating shaft 110. The seal surface of the seal lip 101A is formed of an inclined surface 103 inclined toward the liquid side such as lubricating oil, and an inclined surface 104 inclined toward the atmosphere side. For example, the angle α of the inclined surface 103 with respect to the axial direction of the rotating shaft 110 is made larger than the angle β of the inclined surface 104 (α>β). By doing so, as shown in FIG. 1B, the peak (maximum value) of the pressure distribution where the seal lip 101A presses against the rotating shaft 110 is present on the liquid side. Furthermore, the lubricating oil is easily retained between the seal lip 101A and the rotating shaft 110 due to the minute unevenness, and an oil film 106 is formed. As shown in Fig. 1B, if the peak of the pressure distribution of the seal lip 101A is on the liquid side, a force (pumping force) is generated to push the oil film 106 back to the liquid side when the rotating shaft 110 rotates. This pumping action can suppress leakage of the lubricating oil (liquid) to the atmosphere side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 4-127462 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the seal lip 101A of the oil seal 100 is made of a rubber material and is pressed against the rotating shaft 110 by the spring 102. Therefore, the liquid is sealed at a relatively low sealing pressure (for example, about 0.03 MPa). However, in recent years, when performing cutting processing using a rotary table, the coolant (cutting oil) for discharging cutting chips is increasingly discharged at high pressure (for example, 1 to 7 MPa). Therefore, when the oil seal 100 is used to seal the rotary table, a problem occurs in that when the coolant is sprayed onto the seal lip 101A, the seal lip 101A is turned over and the sealability cannot be maintained. On the other hand, a sealing method is known in which a packing such as an O-ring is placed between the rotating shaft and the support member instead of an oil seal. The packing is generally compressed by about 5 to 20% before installation, and can be strongly pressed against the rotating shaft and can withstand high-pressure coolant. However, when a packing is used, the friction force (friction torque) is higher than when an oil seal is used. As a result, the rotation efficiency decreases, heat generation and wear occur, and the positioning accuracy decreases.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a rotating device that reduces the frictional force generated between a rotating member or a supporting member and a packing while maintaining sealing performance against external forces, and a method for assembling a rotating device. [Means for solving the problem]

[0006] The main invention to achieve the above object is: A rotating member; A support member that supports a peripheral surface of the rotating member; a storage space for storing a lubricant; A rotating device comprising: a packing provided between the rotating member and the support member for preventing leakage of the lubricant, one of the rotating member and the support member includes an annular groove that receives the packing; the other of the rotating member and the support member is in contact with the packing so that the packing is elastically deformed and includes a protruding portion extending annularly along a circumferential surface of the packing; The protrusion is A first inclined surface provided on the housing space side; A second inclined surface provided on the opposite side to the storage space; a contact end portion in contact with the packing, the contact end portion has a portion where the contact pressure with the packing is maximum, The rotating device is characterized in that the maximum portion is located closer to the storage space than the center of the contact end portion in the direction of the rotation axis of the rotating member. Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings. Effect of the Invention

[0007] According to the present invention, it is possible to provide a rotating device that reduces frictional forces generated between a rotating member or a supporting member and a packing while maintaining sealing performance against external forces, and a method for assembling a rotating device. [Brief description of the drawings]

[0008] [Figure 1] 1A and 1B are explanatory diagrams of an oil seal 100. [Diagram 2] 2A and 2B are explanatory diagrams of the barrel cam device 1. [Diagram 3] 1 is an explanatory diagram of a sealing structure 100 of a rotating device (barrel cam device 1). [Figure 4] 4A and 4B are explanatory diagrams of the protrusion 21. FIG. [Diagram 5] 5A and 5B are diagrams showing the state before and after the protruding portion 21 is pressed against the packing 40. FIG. [Figure 6] 13 is a diagram showing changes in contact pressure between the packing 40 and the protrusion 21. FIG. [Figure 7] 13 is a diagram showing a state in which the apex of the protrusion 21 is shifted to the opposite side to the accommodation space 30. FIG. [Figure 8] 13 is a diagram showing a state in which the apex of the protrusion 21 is shifted toward the accommodation space 30. FIG. [Figure 9] 9A to 9D are explanatory views of the annular groove portion 13. FIG. [Figure 10] 10A to 10C are explanatory diagrams of a modified annular groove portion 51. FIG. [Figure 11] 11A and 11B are explanatory diagrams of a modified example of the rotation device 1. FIG. [Figure 12] 13 is a diagram showing an example of a squeeze margin of a packing 40. FIG. [Figure 13] 13A to 13D are explanatory diagrams of another method for assembling the rotating device 1. In FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] At least the following points will become apparent from the description of this specification and the accompanying drawings. (Aspect 1) 1. A rotating device comprising: a rotating member; a support member supporting a peripheral surface of the rotating member; a storage space for storing a lubricant; and a gasket provided between the rotating member and the support member for preventing leakage of the lubricant, wherein one of the rotating member and the support member has an annular groove portion for accommodating the gasket, and the other of the rotating member and the support member has a protrusion that contacts the gasket so that the gasket elastically deforms and extends in an annular shape along the peripheral surface of the gasket, the protrusion having a first inclined surface provided on the storage space side, a second inclined surface provided on the opposite side to the storage space side, and a contact end portion in contact with the gasket, the contact end portion having a portion where the contact pressure with the gasket is maximum, and the maximum portion being located on the storage space side relative to a center of the contact end portion in the direction of the rotational axis of the rotating member.

[0010] According to the first aspect, the distribution of the contact pressure between the packing and the protruding portion can be made similar to that of the contact pressure of an oil seal. Therefore, when the rotating member rotates, a pumping action (a pump force that pushes the lubricant back to the housing space) is thought to act on the lubricant between the packing and the protruding portion, and the sealing between the rotating member and the support member can be improved. This makes it possible to suppress leakage of the lubricant to the outside of the rotating device. In addition, the contact surface between the packing and the protruding portion is not exposed to the outside, and is less susceptible to external forces such as high-pressure coolant, so that the sealing is easily maintained. In addition, the contact width of the packing is smaller than when the packing contacts a flat surface, and therefore the frictional force generated between the packing and the packing can be reduced.

[0011] (Aspect 2) The rotating device according to aspect 1, The inclination angle formed by a virtual plane that passes through the apex of the protrusion and is aligned with the rotation axis direction and the first inclined surface is larger than the inclination angle formed by the virtual plane and the second inclined surface.

[0012] According to the second aspect, the packing is easily deformed so that the portion where the contact pressure between the packing and the protruding portion is maximum is located on the housing space side in the rotation axis direction.

[0013] (Aspect 3) The rotating device according to aspect 1 or aspect 2, The packing is an O-ring, and the contact end of the protrusion is in contact with a central portion of the packing in the direction of the rotation axis.

[0014] According to the third aspect, the first and second inclined surfaces of the protruding portion can be brought into stable contact with the packing. Therefore, the packing is easily deformed so that the portion where the contact pressure between the packing and the protruding portion is maximum is located on the housing space side in the rotation axis direction. In addition, by changing the size and hardness of the O-ring, it can be used in the sealing structure of various rotating devices.

[0015] (Aspect 4) A rotating device according to any one of aspects 1 to 3, The annular groove portion is defined by a first surface and a second surface opposing each other in the direction of the rotation axis, and a third surface connecting the first surface and the second surface, the gasket is in contact with the first surface, the second surface, and the third surface, and one of the rotating member and the support member comprises a first member having the first surface and the third surface, and a second member that is a separate member from the first member and has the second surface.

[0016] According to the fourth aspect, the position of the packing in the rotating device (annular groove portion) can be specified. Therefore, the protrusion can be brought into contact with a desired position (for example, the center) of the packing in the rotation axis direction, and the packing can be deformed by a desired amount of compression by the protrusion. In addition, after the packing is placed on the first surface and the third surface (L-shaped groove), the second surface can be used to cover the packing, and the packing can be brought into contact with the first surface to the third surface while preventing local deformation of the packing.

[0017] (Aspect 5) 1. A method for assembling a rotating device including a rotating member, a support member that supports a peripheral surface of the rotating member, a storage space that stores a lubricant, and a gasket provided between the rotating member and the support member to prevent leakage of the lubricant, the method comprising: a first step of arranging the gasket in an annular groove provided on one of the rotating member and the support member; and a second step of bringing a protruding portion provided on the other of the rotating member and the support member, the protruding portion extending in an annular shape along the peripheral surface of the gasket and having a first inclined surface provided on the storage space side and a second inclined surface provided on the opposite side to the storage space side, into contact with the gasket so that the gasket elastically deforms, wherein in the second step, the protruding portion forms a contact end portion that is in contact with the gasket, and the protruding portion is brought into contact with the gasket so that a portion of the contact end portion where the contact pressure with the gasket is maximum is located closer to the storage space than a center of the contact end portion in the direction of the rotational axis of the rotating member.

[0018] According to the fifth aspect, the distribution of the contact pressure between the packing and the protruding portion can be made similar to that of the oil seal. Therefore, when the rotating member rotates, it is considered that a pumping action is applied to the lubricant between the packing and the protruding portion, and the sealing performance between the rotating member and the support member can be improved. Therefore, the leakage of the lubricant to the outside of the rotating device can be suppressed. In addition, the contact surface between the packing and the protruding portion is not exposed to the outside, and is less susceptible to external forces such as high-pressure coolant, so that the sealing performance can be easily maintained. In addition, the contact width of the packing is smaller than when the packing contacts a flat surface, and therefore the frictional force generated between the packing and the packing can be reduced.

[0019] (Aspect 6) A method for assembling the rotation device according to aspect 5, comprising the steps of: The annular groove portion is defined by a first surface and a second surface opposing each other in the direction of the rotation axis, and a third surface connecting the first surface and the second surface, and after the gasket is placed in a first member having the first surface and the third surface, the gasket is covered with a second member that is a separate member from the first member and has the second surface, thereby bringing the gasket into contact with the first surface and the second surface.

[0020] According to the sixth aspect, the position of the packing in the rotating device (annular groove portion) can be specified. Therefore, the protrusion can be brought into contact with a desired position (for example, the center portion) of the packing in the rotation axis direction. In addition, after the packing is placed on the first and third surfaces (L-shaped grooves), the second surface is used to cover the packing, thereby preventing local deformation of the packing and improving sealing performance.

[0021] ===About Barrel Cam Device 1=== Hereinafter, as an example of a rotation device according to the present invention, an embodiment will be described taking the barrel cam device 1 as an example. The barrel cam device 1 can be used, for example, in an NC table for a machine tool, a positioner for a robot, a rotating shaft for a robot, etc.

[0022] Figures 2A and 2B are explanatory diagrams of the barrel cam device 1. Figure 2A is a schematic plan view of the barrel cam device 1, and Figure 2B is a schematic side view of the barrel cam device 1. Note that in the drawings relating to the present embodiment, including drawings to be described later, appropriate members may be omitted and oblique lines applied to cross sections may be omitted in order to easily explain the present invention.

[0023] The barrel cam device 1 has an X direction, a Y direction, and a Z direction, and the X direction and the Y direction intersect with each other, and the Z direction intersects with both the X direction and the Y direction. The horizontal direction of the paper in Fig. 2A is the X direction, and the left side of the paper is called the left side of the X direction, and the opposite side is called the right side. The vertical direction of the paper is the Y direction, and the upper side of the paper is called the back side of the Y direction, and the opposite side is called the front side. The vertical direction of the paper in Fig. 2B is the Z direction (vertical direction), and the upper side of the paper is called the upper side of the Z direction, and the opposite side is called the lower side.

[0024] The barrel cam device 1 has a housing 2, and the housing 2 accommodates therein an input shaft 3, a barrel cam 70, a rotating shaft body 4, a cam follower 5, a rotating table 10 (rotating member), and a support member 20. In addition, a motor 6 is attached to the housing 2 as a drive unit.

[0025] The motor 6 is provided with its rotating shaft aligned along the Y direction, and is connected to the input shaft 3 by a coupling 7. The input shaft 3 is provided along the Y direction, and is rotatably supported by an input bearing 8. A portion on the front side of the input shaft 3 extends further forward than the input bearing 8, and this extending portion is connected to the rotating shaft of the motor 6 by a coupling 7. In addition, the input shaft 3 is provided on both ends of a barrel cam 70 in the Y direction, and the barrel cam 70 and the input shaft 3 rotate integrally.

[0026] Moreover, the barrel cam 70 has a barrel cam groove 70a, and the spiral barrel cam groove 70a is provided along the direction of the input shaft 3. Then, the rotation of the barrel cam 70 is transmitted to the turntable 10 by engaging the cam follower 5 of the turntable 10 with the barrel cam groove 70a.

[0027] The turntable 10 has a circular shape, and is rotatably supported by a support member 20. The support member 20 supports the turntable 10 via bearings 9. In this embodiment, the bearings 9 are large-diameter four-point supported ball bearings. The turntable 10 includes a plurality of cam followers 5 that engage with a barrel cam 70 (barrel cam groove 70a). Therefore, when the barrel cam 70 rotates around the input shaft 3 along the Y direction, the turntable 10 rotates around a rotation axis along the Z direction.

[0028] The cam follower 5 is a part that engages with the barrel cam groove 70a, is a cylindrical rotating body that can rotate on its own axis, and is provided so that the rotation axis direction is along the Z direction. A plurality of cam followers 5 are provided at equal intervals along a circle centered on the rotation center of the turntable 10. In this embodiment, 16 cam followers 5 are provided at equal intervals.

[0029] Further, the cam follower 5 is engaged with the barrel cam groove 70a of the barrel cam 70 on the underside of the rotary table 10, and the engaged cam follower 5 moves while being guided by the barrel cam groove 70a. Specifically, when the barrel cam 70 rotates counterclockwise as viewed from the front side, the engaged cam follower 5 moves from the front side to the back side along the circumferential direction of the rotary table 10 while being guided by the spiral barrel cam groove 70a. That is, the rotary table 10 rotates clockwise as viewed from above.

[0030] The rotating shaft 4 is attached to the center (hollow portion) of the turntable 10 along the Z direction and rotates integrally with the turntable 10. Note that the rotating shaft 4 in this embodiment is a so-called hollow shaft having a hollow portion, but it may be a solid shaft without a hollow portion.

[0031] ===Sealing structure 100 for rotating device (barrel cam device 1)=== Fig. 3 is an explanatory diagram of the sealing structure 100 of the rotating device (barrel cam device 1). Figs. 4A and 4B are explanatory diagrams of the protruding portion 21. Figs. 5A and 5B are diagrams showing before and after the protruding portion 21 is pressed against the packing 40. Fig. 6 is a diagram showing the change in contact pressure between the packing 40 and the protruding portion 21.

[0032] As described above, a rotating device such as the barrel cam device 1 includes the rotating table 10 which is a rotating member, the support member 20 which supports the peripheral surface of the rotating table 10, and the bearing 9. The rotating table 10 is rotatably supported by the support member 20 via the bearing 9. In the following description, the barrel cam device 1 is also referred to as the rotating device 1.

[0033] The rotating table 10 shown in Fig. 3 includes an upper table 11 and a lower table 12. The upper surface of the upper table 11 is exposed to the outside. Therefore, when the rotating device 1 is used as, for example, an NC rotary table of a machine tool, a workpiece can be placed on the upper surface of the upper table 11. The lower table 12 supports the upper table 11 from below, and a cam follower 5 is attached to the lower table 12. The movement of the cam follower 5 by the barrel cam 70 rotates the lower table 12, and the upper table 11 fixed to the lower table 12 also rotates. The support member 20 supports the peripheral surface facing the lower table 12 via bearings 9.

[0034] A lubricant such as lubricating oil or grease is interposed between the two sliding surfaces between the lower table 12 and the bearing 9 and between the bearing 9 and the support member 20 to reduce friction. For this reason, the rotating device 1 is provided with an accommodation space 30 for accommodating the lubricant at least between the opposing peripheral surfaces of the lower table 12 and the support member 20. To prevent the lubricant in the accommodation space 30 from leaking out of the rotating device 1, the rotating device 1 is provided with a sealing structure 100. The sealing structure 100 is provided between the lower table 12 and the support member 20, and is formed using a packing 40 for preventing leakage of the lubricant, and a protrusion 21 provided on the support member 20.

[0035] The rotary table 10 has an annular groove 13 that houses a packing 40. As shown in Fig. 2A, the annular groove 13 is provided continuously along the circumferential direction of the peripheral surface of the lower table 12 facing the support member 20. In Fig. 3, an O-ring is shown as an example of the packing 40, but the packing 40 is not limited to this. The packing 40 may be any annular member formed of an elastic member that can be deformed by being pressed against the protrusion 21, and may be, for example, a square ring with a square cross section or a D-ring with a D-shaped cross section.

[0036] The protrusion 21 of the support member 20 contacts (presses) the packing 40 so that the packing 40 is elastically deformed, and extends in an annular shape along the circumferential surface of the packing 40 as shown in Fig. 2A. In other words, the protrusion 21 is a portion that is processed and molded on the surface 20a of the support member 20 facing the lower table 12 so as to protrude toward the packing 40 side.

[0037] 4A, the protrusion 21 includes a first inclined surface 211 provided on the storage space 30 side (liquid side) and a second inclined surface 212 provided on the opposite side (atmosphere side) from the storage space 30 side. The first inclined surface 211 is a surface inclined toward the support member 20 side (right side in the X direction) toward the lower side in the Z direction (liquid side). The second inclined surface 212 is a surface inclined toward the support member 20 side (right side in the X direction) toward the upper side in the Z direction (atmosphere side).

[0038] In the rotating device 1 (i.e., when the sealing structure 100 is assembled), as shown in Fig. 5B, the protrusion 21 has a contact end 213 (a portion marked with diagonal lines) in contact with the packing 40. The contact end 213 is a portion where the protrusion 21 elastically deforms the packing 40 and bites into it. As shown in Fig. 6, the contact end 213 has a portion 213x where the contact pressure with the packing 40 is maximum. The maximum portion 213x is located closer to the accommodation space 30 than the center 213c of the contact end 213 in the Z direction (rotation axis direction).

[0039] When the protrusion 21 contacts the packing 40 with a certain amount of crushing allowance, the packing 40 deforms along the first inclined surface 211 and the second inclined surface 212. This amount of deformation (for example, d1 to d4 in FIG. 6) is considered to be generally proportional to the contact pressure between the protrusion 21 and the packing 40 (for example, p1 to p4 in FIG. 6). Therefore, the portion where the amount of deformation of the packing 40 in the X direction becomes maximum (becomes d1 in FIG. 6) is the portion 213x where the contact pressure with the packing 40 becomes maximum. Also, the fact that the portion 213x where the contact pressure becomes maximum is located closer to the accommodation space 30 side than the center 213c of the contact end means that the length D1 in the Z direction from the lowermost end 213l of the contact end 213 to the aforementioned maximum portion 213x is shorter than the length D2 in the Z direction from the maximum portion 213x to the uppermost end 213u of the contact end 213 (D1 < D2).

[0040] Due to the contact pressure distribution between the protrusion 21 and the packing 40 being as described above, the pressure distribution (FIG. 1B) in which the seal lip 101A of the oil seal 100 described above presses against the rotating shaft 110 is reproduced. Therefore, when the rotating table 10 rotates, it is considered that a pumping action (a pump force that pushes the lubricant back toward the accommodation space 30) acts on the lubricant film between the packing 40 and the protrusion 21. Therefore, the sealing performance between the rotating table 10 and the support member 20 is enhanced, and leakage of the lubricant to the outside of the rotating device 1 can be suppressed. For example, leakage of the lubricant from the gap formed between the lower surface of the upper table 11 shown in FIG. 3 and the upper surface of the support member 20 can be suppressed.

[0041] Moreover, the protrusion 21 is a hard member (metal member, hard resin member, etc.) that elastically deforms the packing 40. Therefore, as shown in FIG. 5B, the protrusion 21 bites into the packing 40, and the contact surface (sealing surface) between the packing 40 and the protrusion 21 is not exposed to the outside. Therefore, it is not easily affected by external forces such as high-pressure coolant. Therefore, unlike the seal lip 101A of the oil seal 100, it is not turned over by external forces, and the sealing property is easily maintained. Furthermore, since the protrusion 21 is a hard member, the bottom of the protrusion 21 exposed from the packing 40 is also not easily deformed by external forces, and the sealing property is easily maintained. Furthermore, the protrusion 21 is not easily deformed by the rotational force of the turntable 10, and the sealing property is easily maintained. Therefore, the sealing structure 100 can also suppress the intrusion of foreign matter (for example, high-pressure coolant, etc.) from the external space.

[0042] Another conventional example is a sealing structure in which a flat surface of a support member 20 that does not have a protrusion 21 abuts against a packing 40. Compared to this conventional example, the sealing structure 100 of the present embodiment can reduce the frictional force generated between the support member 20 (protrusion 21) and the packing 40. As a result, it is possible to suppress a decrease in the rotation efficiency of the rotating device 1, heat generation, wear, and a decrease in positioning accuracy.

[0043] Specifically, even if the maximum deformation amount of the packing 40 at the contact surface when the packing 40 is brought into contact with the flat surface of the support member 20 with a predetermined crushing margin and the maximum deformation amount d1 of the packing 40 due to the protruding portion 21 of this embodiment are the same, in the conventional example, the entire arc portion of the packing 40 is crushed, whereas in this embodiment, only the portion along the protruding portion 21 is crushed. Therefore, the deformation amount of the packing 40 is small, and the contact pressure between the support member 20 and the packing 40 is also small. In addition, the contact width between the support member 20 and the packing 40 is smaller in this embodiment than in the conventional example. Therefore, the friction force can be reduced in this embodiment compared to the conventional example.

[0044] A sealing structure 100 was actually manufactured by compressing an O-ring (packing 40) having a diameter of 8.4 mm by 0.5 mm (=d1) in the X direction at the protruding portion 21 (the inclination angle α of the first inclined surface 211 is 45 degrees, and the inclination angle β of the second inclined surface 212 is 30 degrees) on a rotating table 10 having a diameter of 400 mm, and a verification test was performed. Machine oil having a viscosity of 260 cst was used as the lubricant, and the rotating table 10 was rotated in both forward and reverse directions at a rotation speed of 50 RPM and operated for about 1000 hours. As a result, it was confirmed that no leakage of the lubricant to the outside of the rotating device 1 occurred. It was also confirmed that the friction force (friction torque) was about 1 / 10 compared to a rotating device of a comparative example under the same conditions except that the support member 20 is a flat surface without the protruding portion 21.

[0045] As described above, according to the rotating device 1 of this embodiment, the frictional force generated between the support member 20 and the packing 40 can be suppressed while maintaining the sealing performance against external forces. In addition, the sealing structure 100 using the packing 40 as in this embodiment can reduce the size of the rotating device 1 compared to when an oil seal (FIG. 1A) is used. Also, various types of packing 40 such as O-rings are standardized and distributed with different sizes, hardness, materials, etc. Therefore, the sealing structure 100 of this embodiment can be applied to various rotating devices by changing the size, hardness, etc. of the packing 40. Also, when the packing 40 is an O-ring, it is difficult to install it incorrectly because the cross-sectional shape is symmetrical.

[0046] The protrusion 21 may be a separate member from the support member 20, and may be formed by being fixed to the opposing surface 20a of the support member 20. However, it is preferable that the opposing surface 20a of the support member 20 is processed and formed integrally with the support member 20 using the same material (e.g., a metal material, etc.). This prevents a gap from occurring between the protrusion 21 and the support member 20, and also makes it easier to improve the accuracy of the dimensions and arrangement of the protrusion 21, thereby further improving the sealing performance of the rotating device 1.

[0047] 4A illustrates an example in which the corner (top of protrusion 21) where first inclined surface 211 and second inclined surface 212 intersect has a V-shaped cross section, but the present invention is not limited thereto. For example, as shown in FIG. 4B, the corner of first inclined surface 211 and second inclined surface 212 may be rounded and the cross section of the corner may be curved. In this case, the contact of top 21t of protrusion 21 with packing 40 becomes gentler, making it less likely for cracks to occur in packing 40 and enabling the life of packing 40 to be extended.

[0048] 4A, the inclination angle α of the first inclined surface 211 with respect to a virtual plane Vf that passes through the apex 21t of the protrusion 21 and is along the Z direction, which is the rotation axis direction, is preferably larger than the inclination angle β of the second inclined surface 212 with respect to the virtual plane Vf (α>β). In this embodiment, a case where α is 45 degrees and β is 30 degrees is illustrated, but the present invention is not limited to this. In other words, the angle α' (=180-45 degrees) formed by the first inclined surface 211 and the opposing surface 20a of the support member 20 is preferably smaller than the angle β' (=180-30 degrees) formed by the second inclined surface 212 and the opposing surface 20a of the support member 20.

[0049] As shown in FIG. 6, the contact pressure with the packing 40 is likely to be maximum at the apex 21t of the protrusion 21. Therefore, by increasing the inclination angle α of the first inclined surface 211, the length D1 in the Z direction where the first inclined surface 211 contacts the packing 40 is likely to be shorter than the length D2 in the Z direction where the second inclined surface 212 contacts the packing 40. Therefore, the packing 40 is likely to deform so that the portion 213x of the contact end portion 213 of the protrusion 21 where the contact pressure with the packing 40 is maximum is located on the accommodation space 30 side in the Z direction. Therefore, a pumping action works on the lubricant between the packing 40 and the protrusion 21, and the sealing performance between the rotary table 10 and the support member 20 is improved.

[0050] However, the inclination angle α is not limited to the above, and may be the same as or smaller than the inclination angle β. In that case, it is sufficient that the portion 213x of the contact end 213 where the contact pressure is maximum is located on the accommodation space 30 side by devising the position where the protrusion 20 abuts on the packing 40 or the shape of the packing 40.

[0051] Fig. 7 is a diagram showing a state in which the apex 21t of the protrusion 21 is shifted to the opposite side (to the atmosphere side) from the accommodation space 30. Fig. 8 is a diagram showing a state in which the apex 21t of the protrusion 21 is shifted to the accommodation space 30 side (to the liquid side).

[0052] When the packing 40 is an O-ring, it is preferable that the protrusion 21 contacts the center of the packing 40 in the Z direction. In the O-ring, the surface facing the protrusion 21 is curved. Therefore, by the protrusion 21 contacting the center of the packing 40 in the Z direction, both the first inclined surface 211 and the second inclined surface 212 of the protrusion 21 can be stably contacted with the packing 40. Therefore, the packing 40 can be deformed so that the portion 213x of the contact end 213 where the contact pressure is maximum is positioned on the accommodation space 30 side, and the gap between the rotary table 10 and the support member 20 can be sealed.

[0053] In addition, the protrusion 21 contacting the center of the packing 40 in the Z direction does not necessarily mean that the apex 21t of the protrusion 21 and the center of the packing 40 (O-ring) are aligned in the Z direction as shown in FIG. 6. The apex 21t of the protrusion 21 may be slightly offset from the center of the packing 40 as shown in FIG. 7 and FIG. 8. FIG. 7 and FIG. 8 show a state in which the apex 21 of the protrusion 21 is offset from the center of the packing 40 by about 0.5 mm when the diameter of the packing 40 is 10 mm. However, if the protrusion 21 is significantly offset from the center of the packing 40 in the Z direction, the portion of the protrusion 21 that contacts the packing 40 becomes smaller, and the distribution of the contact pressure also changes. Therefore, the protrusion 21 is considered to contact the center of the packing 40 in the Z direction when the pressure distribution is maintained such that the portion 213x of the contact end 213 where the contact pressure is maximum is located on the side of the accommodation space 30.

[0054] 7 shows a case where the apex 21t of the protrusion 21 is shifted in the Z direction toward the opposite side (atmosphere side) of the accommodation space 30 from the center of the packing 40. In this case as well, the portion 213x where the contact pressure is maximum is located on the accommodation space 30 side, and the length D3 from the bottom end 213l of the contact end 213 to the maximum portion 213x is shorter than the length D4 from the maximum portion 213x to the top end 213u of the contact end 213. Therefore, a pumping action is generated, and the gap between the rotating member 10 and the support member 20 is sealed.

[0055] 8 shows a case where the apex 21t of the protrusion 21 is shifted toward the accommodation space 30 (liquid side) from the center of the packing 40 in the Z direction. In this case as well, the portion 213x where the contact pressure is maximum is located on the accommodation space 30 side, and the length D5 from the bottom end 213l of the contact end 213 to the maximum portion 213x is shorter than the length D6 from the maximum portion 213x to the top end 213u of the contact end 213. Therefore, a pumping action is generated, and the gap between the rotating member 10 and the support member 20 is sealed.

[0056] 9A to 9D are explanatory diagrams of the annular groove 13. FIGS. 10A to 10C are explanatory diagrams of a modified annular groove 51. The annular groove 13 of the rotary table 10 is defined by a first surface S1 and a second surface S2 that face each other in the Z direction, and a third surface S3 that connects the first surface S1 and the second surface S2. In this case, in the rotating device 1 (i.e., in a state in which the sealing structure 100 is assembled), it is preferable that the packing 40 is in contact with the first surface S1, the second surface S2, and the third surface S3.

[0057] By doing so, there is no clearance in the Z direction in the annular groove portion 13 that accommodates the packing 40, and the position of the packing 40 in the Z direction in the rotating device 1 can be determined. Therefore, the protrusion 21 can be brought into contact with the center of the packing 40 in the Z direction (as in any of Figs. 6 to 8). Therefore, the packing 40 can be deformed so that the portion 213x of the contact end portion 213 where the contact pressure is maximum is located on the housing space 30 side. In addition, the position of the packing 40 in the X direction in the rotating device 1 is also determined. Therefore, the protrusion 21 can be caused to bite into the packing 40 with a desired amount of compression, and a desired contact pressure can be obtained. Therefore, the sealing performance between the rotating table 10 and the support member 20 can be improved.

[0058] Furthermore, it is preferable that the rotating table 10 includes a lower table 12 (first member) having a first surface S1 and a third surface S3 that form the annular groove portion 13, as shown in FIG. 9A, and an upper table 11 (second member) that is a separate member from the lower table 12 and has a second surface S2.

[0059] The annular groove portion that houses the packing 40 may be a U-shaped groove 51 (horizontal U-shaped groove) provided in an inseparable member 50 (rotating member or support member) as shown in Fig. 10A. In this case, the packing 40 can be installed in contact with three surfaces that define the U-shaped groove 51 as shown in Fig. 10C. However, if an attempt is made to fit the packing 40 into the U-shaped groove 51 without any clearance, local deformation (dentation) of the packing 40 may occur.

[0060] Therefore, as described above, it is preferable that the annular groove portion 13 is composed of a plurality of disassembled members (upper table 11 and lower table 12). In this way, as shown in Fig. 9B, after placing the packing 40 on the first surface S1 and the third surface S3 (L-shaped groove) of the lower table 12, as shown in Fig. 9C, the packing 40 can be covered with the second surface S2 of the upper table 11. Therefore, while the packing 40 is in contact with the first surface S1 to the third surface S3, local deformation (depression due to elongation) of the packing 40 can be prevented, and a decrease in sealing performance due to local deformation can be prevented. In addition, it is also possible to prevent an increase in friction in a portion of the packing 40 where the packing 40 has shrunk due to local deformation and has a larger diameter.

[0061] <<Modifications>> 11A and 11B are explanatory diagrams of a modified example of the rotating device 1. In FIG. 3, the packing 40 is accommodated in the rotating table 10 (rotating member), but as shown in FIG. 11, an annular groove 22 may be provided in the support member 20, and the packing 40 may be accommodated in the annular groove 22. In this case, the rotating table 10 (lower table 12) may be provided with a protrusion 14 that extends annularly along the circumferential surface of the packing 40. An example of the protrusion 14 is one that is processed and molded so as to protrude toward the packing 40 on the surface 12a of the lower table 12 facing the support member 20.

[0062] Like the above-mentioned protrusion 21, the protrusion 14 of the turntable 10 may also have a first inclined surface 141 provided on the lubricant storage space 30 side and a second inclined surface 142 provided on the opposite side, as shown in Fig. 11B. The contact end 143 of the protrusion 14 in contact with the packing 40 may have a portion where the contact pressure with the packing 40 is maximum, and the maximum portion may be located on the storage space 30 side. In this way, the distribution of the contact pressure between the protrusion 14 and the packing 40 becomes similar to the contact pressure of the oil seal 100, and a pumping action is generated, improving the sealing performance between the turntable 10 and the support member 20.

[0063] 11 includes a lower support member 201 that forms an L-shaped groove, and an upper support member 202 that covers the L-shaped groove from above. This allows the packing 40 to be placed in the annular groove portion 22 without local deformation of the packing 40 while being in contact with three surfaces that define the annular groove portion 22.

[0064] In FIG. 11, the packing 40 is provided on the support member 20 side. Therefore, it is preferable that the friction force (total value of static friction forces) generated between the packing 40 and each of the three surfaces of the annular groove portion 22 is more than twice the rotational force (rotational torque) of the rotating member 10, that is, the rotational friction force between the protrusion 14 and the packing 40. By doing so, the packing 40 becomes less likely to move compared to a case where the friction force between the packing 40 and the annular groove portion 22 is less than twice the rotational force of the rotating member 10, and it is possible to suppress the packing 40 from rotating due to the rotational force of the rotating member 10. The static friction force between the packing 40 and the annular groove portion 22 and the rotational friction force between the protrusion 14 and the packing 40 can be obtained by actual measurement.

[0065] FIG. 12 is a diagram showing an example of the crushing allowance of the packing 40. When the total value of the deformation amount of the packing 40 due to the three faces of the annular groove portion 22 (total value of the crushed cross-sectional areas a401, a402, and a403) is larger than the deformation amount of the packing 40 due to the protrusion 14 (the crushed cross-sectional area a14), the packing 40 can be fixed to the annular groove portion 22 side, and the packing 40 can be prevented from rotating. Specifically, when the diameter of the packing 40 (O-ring) is D, the crushing allowances on the upper and lower sandwiching faces are each set to 0.06D, and the crushing allowance on the face along the Z direction is set to 0.04D. On the other hand, the crushing allowance due to the protrusion 14 is set to 0.06D. In this case, although there is uncertainty due to the roughness of each face and the variation in the friction coefficient, the static friction force between the packing 40 and the annular groove portion 22 is likely to be about twice the rotational friction force between the protrusion 14 and the packing 40.

[0066] This is true not only for the modified example, but also for the above-described embodiment (FIG. 3). In other words, the total value of the deformation amount of the packing 40 due to the three faces of the annular groove portion 13 on the rotating member 10 side should be greater than the deformation amount of the packing 40 due to the protruding portion 21 on the supporting member 20 side. By doing so, the packing 40 is fixed to the annular groove portion 13, the positional deviation of the packing 40 with respect to the rotating annular groove portion 13 is unlikely to occur, and the packing 40 can rotate together with the annular groove portion 13. It is preferable that the frictional force generated between the packing 40 and each of the three faces of the annular groove portion 13 is more than twice the rotational frictional force between the protruding portion 21 and the packing 40. By doing so, the packing 40 is more reliably fixed to the annular groove portion 13, and the packing 40 can rotate together with the annular groove portion 13.

[0067] 3, a four-point support ball bearing is shown as an example of the bearing 9, but the present invention is not limited to this. For example, the bearing 9 may be a cross roller bearing (not shown) or the like.

[0068] ====How to assemble the rotating device 1=== Next, a method of assembling the rotating device 1 including the rotating table 10, the support member 20, the housing space 30 for housing a lubricant, and the packing 40 will be described.

[0069] The assembly method includes a first step of placing the gasket 40 in an annular groove portion (annular groove portion 13 in FIG. 3 or annular groove portion 22 in FIG. 11A) provided on one of the rotating table 10 and the support member 20, and a second step of bringing a protrusion (protrusion 21 in FIG. 3 or protrusion 14 in FIG. 11A) provided on the other of the rotating member 10 and the support member 20 into contact with the gasket 40, the protrusion (21 or 14) extending in a ring shape along the circumferential surface of the gasket 40 and having a first inclined surface (211 or 141) provided on the storage space 30 side and a second inclined surface (212 or 142) provided on the opposite side.

[0070] In the second step, a contact end portion (213 or 143) is formed, which is the portion where the protrusion (21 or 14) contacts the packing 40, and the protrusion (21 or 14) is brought into contact with the packing 40 so that the portion of the contact end portion (213 or 143) where the contact pressure with the packing 40 is maximum is located closer to the accommodating space 30 than the center of the contact end portion (213 or 143) in the Z direction.

[0071] According to the rotating device 1 assembled by the above-mentioned assembly method, the distribution of the contact pressure between the protrusion (21 or 14) and the packing 40 is similar to the distribution of the contact pressure of the oil seal 100. Therefore, a pumping action is generated, and the sealing performance between the rotating table 10 and the support member 20 is improved.

[0072] Furthermore, the annular groove may be an inseparable U-shaped groove 51 (see FIG. 10A), but may be formed of a member having a first surface S1 and a third surface S3 that are L-shaped grooves and a member having a second surface S2 that is a separate member, as shown in FIG. 9A. In this case, as shown in FIG. 9B, first, the packing 40 may be placed on the member having the first surface S1 and the third surface S3 that are L-shaped grooves (here, the lower table 12). After that, the packing 40 may be covered with a member having the second surface S2 that is a separate member from the member having the L-shaped groove (here, the upper table 11), thereby bringing the packing 40 into contact with the first surface S1 and the second surface S2.

[0073] By doing so, the position of the packing 40 in the Z direction is defined, and the protruding portion (21 or 14) can be brought into contact with a desired position (for example, the center) of the packing 40 in the Z direction. Therefore, the packing 40 can be deformed so that the portion where the contact pressure between the protruding portion (21 or 14) and the packing 40 is maximum is located on the accommodation space 30 side. Also, compared to the case where the packing 40 is fitted into the U-shaped groove 51 that cannot be disassembled, local deformation of the packing 40 can be suppressed, and the sealing performance between the rotary table 10 and the support member 20 is improved.

[0074] 9D, the packing 40 may be brought into contact with the third surface S3 by bringing the protruding portion (21 or 14) into contact (pressing) with the packing 40. In this way, the position of the packing 40 in the X direction is determined, and the protruding portion (21 or 14) can be pressed into the packing 40 by a desired amount, thereby obtaining a desired contact pressure.

[0075] 13A to 13D are explanatory diagrams of another method of assembling the rotating device 1. As shown in Fig. 13B, after a first step of placing the packing 40 in an L-shaped groove having a first surface S1 and a third surface S3, as shown in Fig. 13C, a second step of bringing the protruding portion (21 or 14) into contact with the packing 40 may be performed, and finally, a step of covering the packing 40 with the second surface S2 may be performed.

[0076] Even in this case, the protrusion (21 or 14) can be brought into contact with a desired position (for example, the center) of the packing 40 in the Z direction. Therefore, the packing 40 can be deformed so that the portion of the contact end (213 or 143) where the contact pressure with the packing 40 is maximum is located on the accommodation space 30 side. Furthermore, according to the above assembly method, unlike the case where the packing 40 is fitted into a U-shaped groove, local deformation (depression due to stretching) of the packing 40 can be prevented, and a decrease in sealing performance can be prevented. Furthermore, it is also possible to prevent an increase in friction in the portion of the packing 40 where the diameter has increased due to shrinkage caused by local deformation.

[0077] The above-mentioned embodiment is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be modified or improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof.

[0078] For example, the barrel cam device 1 has been illustrated as an example of a rotating device, but the present invention is not limited thereto. The rotating device may be, for example, a device in which a rotating member is rotated directly by a motor or indirectly via gears or the like. In addition, although the rotating device 1 is illustrated as being used as an NC table for a machine tool, the rotating device 1 (sealing structure 100) of this embodiment can be used in various machines (vehicles, construction machines, air conditioning equipment, robots, etc.). [Explanation of symbols]

[0079] 1 Rotating device (barrel cam device) 2 Housing, 3 Input shaft, 4 Rotating shaft body, 5 Cam follower, 6 Motor, 7 coupling, 8 input bearing, 9 bearings, 10 Rotating table (rotating member), 11 upper table, 12 lower table, 13 annular groove portion, 14 protrusion portion, 20 Support member, 21 Protrusion, 22 annular groove portion, 30 Storage space, 40 packing, 51 U-shaped groove, 70 barrel cam, 100 Oil seal, 101 Rotating shaft

Claims

1. A rotating member; A support member that supports a peripheral surface of the rotating member; a storage space for storing a lubricant; A rotating device comprising: a packing provided between the rotating member and the support member for preventing leakage of the lubricant, one of the rotating member and the support member includes an annular groove that receives the packing; the other of the rotating member and the support member is in contact with the packing so that the packing is elastically deformed and includes a protruding portion extending annularly along a circumferential surface of the packing; The protrusion is A first inclined surface provided on the housing space side; A second inclined surface provided on the opposite side to the storage space; a contact end portion in contact with the packing, the contact end portion has a portion where the contact pressure with the packing is maximum, A rotating device, characterized in that the maximum portion is located closer to the storage space than the center of the contact end portion in the direction of the rotation axis of the rotating member.

2. 2. The rotating device according to claim 1, A rotation device characterized in that an inclination angle formed by a virtual plane passing through the apex of the protrusion and along the rotation axis direction and the first inclined surface is greater than an inclination angle formed by the virtual plane and the second inclined surface.

3. A rotating device according to claim 1 or 2, The packing is an O-ring, A rotating device, characterized in that the contact end of the protrusion is in contact with a central portion of the packing in the rotation axis direction.

4. A rotating device according to claim 1 or 2, the annular groove portion is defined by a first surface and a second surface opposed to each other in the rotation shaft direction, and a third surface connecting the first surface and the second surface, the packing is in contact with the first surface, the second surface, and the third surface; A rotating device characterized in that one of the rotating member and the support member comprises a first member having the first surface and the third surface, and a second member that is a separate member from the first member and has the second surface.

5. A rotating member; A support member that supports a peripheral surface of the rotating member; a storage space for storing a lubricant; A method for assembling a rotating device including a packing provided between the rotating member and the support member to prevent leakage of the lubricant, comprising the steps of: a first step of disposing the packing in an annular groove portion provided in one of the rotating member and the support member; A protrusion provided on the other of the rotating member and the support member, The packing has a circumferential surface extending in an annular shape, and a second step of bringing the protruding portion, which has a first inclined surface provided on the accommodation space side and a second inclined surface provided on the opposite side to the accommodation space side, into contact with the packing so that the packing is elastically deformed; Equipped with In the second step, The protrusion forms a contact end portion which is a portion that contacts the packing, A method for assembling a rotating device, characterized in that the protrusion is brought into contact with the packing so that the portion of the contact end where the contact pressure with the packing is maximum is located closer to the accommodating space than the center of the contact end in the direction of the rotational axis of the rotating member.

6. A method for assembling a rotating device according to claim 5, comprising the steps of: the annular groove portion is defined by a first surface and a second surface opposed to each other in the rotation shaft direction, and a third surface connecting the first surface and the second surface, A method for assembling a rotating device, comprising: placing the gasket on a first member having the first surface and the third surface; and covering the gasket with a second member that is a separate member from the first member and has the second surface, thereby bringing the gasket into contact with the first surface and the second surface.

Images