Rotary Table Device
The rotary table device addresses fluid leakage issues by using annular grooves and slip rings to stabilize the seal ring, ensuring a reliable seal despite high-speed rotation.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2026-03-10
AI Technical Summary
Existing rotary seal devices in rotary tables experience instability and fluid leakage due to the seal ring rotating at high speed, which weakens its contact with the rod under centrifugal force, leading to potential fluid leaks.
A rotary table device with a through hole and shaft-side and table-side fluid passages, featuring annular grooves and a seal ring tightly fixed to the shaft, and slip rings that maintain contact with the seal ring to prevent rotation and fluid leakage.
The solution effectively prevents fluid leakage by ensuring the seal ring remains stationary relative to the shaft, even at high rotational speeds, thus maintaining a tight seal.
Smart Images
Figure 2026040910000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a rotary table apparatus, and more particularly to a rotary table apparatus equipped with a rotary joint that supplies fluid to a rotary table. [Background technology]
[0002] The rotary joint installed in a rotary table device is used to supply fluids such as hydraulic pressure, air pressure, and coolant to jigs on the rotary table, and is composed of a rotating part attached to the rotary table, a non-rotating part attached to the frame, and multiple fluid passages formed in the rotating and non-rotating parts. A sealing mechanism is provided to prevent fluid leakage from the point where the rotating and non-rotating parts connect.
[0003] A typical sealing mechanism, for example, places a seal ring and an O-ring in a seal groove provided on the rotating part side, and presses the seal ring against the shaft using the interference of the O-ring to prevent fluid from leaking from the gap between the joint sleeve and the shaft.
[0004] Furthermore, as a sealing device used in a rotating part of a fluid pressure device, for example, the device described in Japanese Patent Laid-Open No. 8-189567 (Patent Document 1) is known. Patent Document 1 discloses that a seal ring is brought into close contact with a rod rotating at high speed, and the seal ring rotates together with the rod to prevent liquid leakage. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] Japanese Patent Publication No. 8-189567 Summary of the Invention [Problem to be solved by the invention]
[0006] In the rotary seal device of Patent Document 1, the seal ring is simply pressed against the rod by fluid pressure, so a drop in fluid pressure can cause instability in the seal ring's contact with the rod. Also, because the seal ring rotates with the rod, when the rod rotates at high speed, the seal ring also rotates at high speed, causing it to spread out under the influence of centrifugal force, weakening its contact with the rod.
[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a rotary table device that can reliably prevent fluid leakage. [Means for solving the problem]
[0008] For this purpose, a rotary table device according to one aspect of the present invention comprises a rotary table having a through hole extending along the rotation axis, a frame that rotatably supports the rotary table from its back side, a shaft that is inserted into the through hole and supplies fluid, a shaft-side fluid passage that is provided inside the shaft and has its outlet on the outer surface of the shaft, a table-side fluid passage that includes a vertical passage that leads to the table surface, a horizontal passage that is perpendicular to the vertical passage, and a connecting passage that connects to the outlet of the shaft-side fluid passage, a plurality of annular grooves that are provided on the inner surface of the rotary table and are arranged on either side of the connecting passage, and a seal ring that is arranged in the annular groove and is tightly fixed to the shaft, and the seal ring abuts liquid-tightly against the wall surface of the annular groove.
[0009] Preferably, the seal ring has an inner diameter smaller than the outer diameter of the shaft before being fitted onto the shaft.
[0010] Preferably, the rotary table device further includes a pair of slip rings disposed between both axial ends of the seal ring and the annular groove.
[0011] Preferably, the slip ring includes a first surface that abuts against the seal ring and a second surface that abuts against a wall surface of the annular groove, and the friction force generated between the first surface and the seal ring is smaller than the friction force generated between the second surface and the wall surface of the annular groove. [Effects of the Invention]
[0012] According to the present invention, leakage of fluid can be reliably prevented. [Brief explanation of the drawings]
[0013] [Figure 1] 1 is a schematic cross-sectional view showing a schematic configuration of a rotary table device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view of a part of FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view of a part of FIG. 2. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a part of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION
[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which the same or corresponding parts are designated by the same reference numerals and will not be described repeatedly.
[0015] Fig. 1 is a schematic cross-sectional view showing the general configuration of a rotary table device according to an embodiment of the present invention, and Figs. 2 to 4 are enlarged cross-sectional views. The configuration of the rotary table device will be described with reference to Figs. 1 to 4.
[0016] 1, the rotary table device 1 includes a rotary table 2 having a through hole 2a extending along a rotation axis O, a frame 7 that rotatably supports the rotary table 2 from its back side, and a shaft 3 that is inserted through the through hole 2a and supplies a fluid such as hydraulic pressure. The main elements of the rotary table device 1, namely the rotary table 2, the shaft 3, and the frame 7, are formed, for example, from rigid bodies.
[0017] The rotary table 2 has a table surface 2b formed on its surface as a workpiece mounting portion, which chucks a workpiece (not shown). The rotary table 2 is driven to rotate around a rotation axis O as the center of rotation by a drive unit (not shown) provided on a frame 7. A control unit (not shown) detects the rotation position of the rotary table 2 and controls the drive unit to set the rotary table 2 to a desired index angle. In other words, the rotary table 2 is a rotating member.
[0018] As shown in Fig. 2, the turntable 2 includes a joint sleeve 20 and a circular table main body 21 that surrounds the outer periphery of the joint sleeve 20. The joint sleeve 20 and the circular table main body 21 are connected by, for example, bolts. A plurality of annular grooves 23 are provided on the inner periphery of the joint sleeve 20 at intervals in the vertical direction along the rotation axis O. The annular grooves 23 will be described later.
[0019] 2, the shaft 3 is a non-rotating member and is supported by a rolling bearing provided in the joint sleeve 20. The outer peripheral surface of the shaft 3 faces the inner peripheral surface of the joint sleeve 20. The frame 7 is a non-rotating member and forms the framework of the rotary table device 1.
[0020] 2, the rotary table device 1 is provided with a shaft-side fluid passage 5 and a table-side fluid passage 4. The shaft-side fluid passage 5 is provided inside the shaft 3, and its outlet 52 is provided on the outer circumferential surface of the shaft 3. The shaft-side fluid passage 5 and the table-side fluid passage 4 are passages for supplying fluids such as hydraulic pressure to the table surface 2b of the rotary table 2.
[0021] Specifically, the shaft-side fluid passage 5 includes a shaft-side vertical passage 50 extending along the rotation axis O of the shaft 3, and a shaft-side horizontal passage 51 perpendicular to the shaft-side vertical passage 50. One end of the shaft-side horizontal passage 51 is connected to an outlet 52 provided on the outer surface of the shaft 3.
[0022] The table-side fluid passage 4 includes a table-side vertical passage 40 that connects to the table surface 2b, a table-side horizontal passage 41 that is perpendicular to the table-side vertical passage 40, and a table-side connecting passage 42 that connects to an outlet 52 of the shaft-side fluid passage 5. The table-side connecting passage 42 is an annular groove that is provided along the inner periphery of the joint sleeve 20.
[0023] As described above, the turntable 2 has a plurality of annular grooves 23 formed on its inner peripheral surface. The plurality of annular grooves 23 are arranged on either side of the table-side connecting passage 42 provided in the turntable 2. Specifically, the annular grooves 23 are provided on both ends of the table-side connecting passage 42 in the rotation axis direction, i.e., on the top and bottom. As shown in FIG. 4 , the annular groove 23 is a U-shaped recess that opens toward the shaft 3 in a vertical cross-sectional view, and includes a standing wall surface 24 located away from the inner peripheral surface of the joint sleeve 20, an upper wall surface 25 continuous with the upper side of the standing wall surface 24, and a lower wall surface 26 continuous with the lower side of the standing wall surface 24. A seal ring 60 is disposed in the annular groove 23.
[0024] The seal ring 60 is an elastic body made of, for example, a synthetic resin. Examples of synthetic resin materials include fluororesin, polyethylene resin, and polyurethane resin. The seal ring 60 has a generally rectangular shape in cross section and has corners, but may also have rounded or curved surfaces. A gap is provided between the seal ring 60 and the vertical wall surface 24 of the annular groove 23. A thickness dimension W1 of the seal ring 60 in a direction perpendicular to the rotation axis O is smaller than an axial dimension S1 of the annular groove 23.
[0025] The seal ring 60 is in liquid-tight contact with the wall surfaces 25, 26 of the annular groove 23 via a pair of slip rings 61. The liquid-tight state means that the seal ring 60 is pressed against the slip ring 61 by fluid pressure, so that the two are in close contact with each other with no gaps. The slip ring 61 will be described later.
[0026] The seal ring 60 is tightly fixed to the outer circumferential surface of the shaft 3. Specifically, the inner diameter of the seal ring 60 before being fitted onto the shaft 3 is smaller than the outer diameter of the shaft 3. This allows the seal ring 60 to be tightly fixed to the outer circumferential surface of the shaft 3 by its own elastic force.
[0027] For ease of understanding, in Figures 2 to 4, the inner diameter dimension of the seal ring 60 is smaller than the outer diameter dimension of the shaft 3, but this is only an exaggerated illustration of the tightly fixed state of the seal ring 60 relative to the shaft 3; in reality, the shaft 3 is a rigid body, so the seal ring 60 does not bite into the shaft 3.
[0028] As described above, a pair of slip rings 61 are provided between the axial ends of the seal ring 60 and the annular groove 23. The slip rings 61 are elastic and made of, for example, synthetic resin. Examples of synthetic resin materials include polyacetal resin and polyamide resin. The slip rings 61 have, for example, a generally flat cross-sectional shape. The thickness dimension W2 of the slip ring 61 in a direction perpendicular to the rotation axis O is smaller than the axial dimension S1 of the annular groove 23 and larger than the thickness dimension W1 of the seal ring 60.
[0029] 4, the upper slip ring 61 includes a first surface 62 that contacts the upper surface of the seal ring 60 and a second surface 63 that contacts the upper wall surface 25 of the annular groove 23. The lower slip ring 61 includes a first surface 62 that contacts the lower surface of the seal ring 60 and a second surface 63 that contacts the lower wall surface 26 of the annular groove 23. Specifically, the first surface 62 of the slip ring 61 contacts the upper surface of the seal ring 60 in a liquid-tight manner over the entire width, and the second surface 63 contacts the upper wall surface 25 of the annular groove 23 over the entire width. As a result, the seal ring 60 is arranged in the annular groove 23 while being sandwiched between the pair of slip rings 61 from above and below.
[0030] The thickness W2 of the slip ring 61 is larger than the thickness W1 of the seal ring 60. Therefore, due to the difference in their dimensions, the contact area between the first surface 62 of the slip ring 61 and the seal ring 60 is narrow, resulting in a small frictional force. In contrast, the contact area between the second surface 63 of the slip ring 61 and the annular groove 23 is wide, resulting in a large frictional force. Furthermore, the first surface 62 of the slip ring 61 and the seal ring 60 are both made of synthetic resin, resulting in a small frictional force and good sliding. In contrast, the second surface 63 of the slip ring 61 and the joint sleeve 20 are made of synthetic resin and metal, resulting in a large frictional force and poor sliding. Therefore, the frictional force generated between the first surface 62 and the seal ring 60 is smaller than the frictional force generated between the second surface 63 and the wall surface of the annular groove 23.
[0031] This allows the slip ring 61 to rotate along with the rotation of the rotary table 2, and although the seal ring 60 is integrally fixed to the shaft 3, it is possible to prevent the seal ring 60 from rotating along with the rotation of the joint sleeve 20.
[0032] In the rotary table apparatus 1 of this embodiment, the seal ring 60 provided in the multiple annular grooves 23 provided on the inner circumferential surface of the turntable 2 is tightly fixed to the shaft 3, so the seal ring 60 and the shaft 3 are integrated. Therefore, even when the turntable 2 rotates relative to the shaft 3, no sliding occurs between the seal ring 60 and the shaft 3, preventing wear on the shaft 3. Furthermore, in the rotary table apparatus 1 of this embodiment, because the rotating part is the turntable 2, the seal ring 60 is not affected by centrifugal force. This prevents the seal ring 60 from expanding due to centrifugal force and weakening its tight contact with the shaft 3.
[0033] Furthermore, seal ring 60 of this embodiment is in liquid-tight contact with wall surfaces 25, 26 of annular groove 23 via slip ring 61, thereby preventing fluid flowing through fluid passages 4, 5 from leaking from outlet 52. In this way, rotary table device 1 of this embodiment can reliably prevent fluid leakage.
[0034] Furthermore, the seal ring 60 is in contact with the wall surfaces 25, 26 of the annular groove 23 via the slip ring 61, but the first surface 62 of the slip ring 61 that contacts the seal ring 60 is set to have lower friction than the second surface 63 that contacts the wall surfaces 25, 26 of the annular groove 23, so that the seal ring 60 can be prevented from rotating as the joint sleeve 20 rotates.
[0035] In this embodiment, a pair of slip rings 61, 61 are provided between the seal ring 60 and the wall surfaces 25, 26 of the annular groove 23, but the pair of slip rings 61 is not necessarily provided, as long as at least the seal ring 60 is disposed within the annular groove 23. In this case, it is preferable that the upper wall surface 25 of the annular groove 23 and the upper surface of the seal ring 60, and the lower wall surface 26 of the annular groove 23 and the lower surface of the seal ring 60 abut in a liquid-tight manner.
[0036] Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as the present invention or within an equivalent scope. [Industrial Applicability]
[0037] The present invention is advantageously used in machine tools. [Explanation of symbols]
[0038] 1 rotary table device, 2 rotary table, 2a through hole, 2b table surface, 3 shaft, 4 table side fluid passage, 5 shaft side fluid passage, 23 annular groove, 24, 25, 26 wall surface, 40 table side vertical passage, 41 table side horizontal passage, 42 table side connecting passage, 52 outlet, 60 seal ring, 61 slip ring, 62 first surface, 63 second surface, O rotation axis.
Claims
1. a rotary table having a through hole extending along a rotation axis; a frame that rotatably supports the rotary table from its rear side; a shaft that is inserted into the through hole and that supplies a fluid; a shaft-side fluid passage provided inside the shaft and having an outlet provided on an outer peripheral surface of the shaft; a table-side fluid passage including a vertical passage leading to the table surface, a horizontal passage perpendicular to the vertical passage, and a connecting passage leading to an outlet of the shaft-side fluid passage; a plurality of annular grooves provided on an inner peripheral surface of the rotary table and disposed on either side of the connecting passage; a seal ring disposed in the annular groove and tightly fixed to the shaft; The seal ring is in liquid-tight contact with a wall surface of the annular groove.
2. 2. The rotary table apparatus according to claim 1, wherein the inner diameter of the seal ring before being fitted onto the shaft is smaller than the outer diameter of the shaft.
3. 2. The rotary table apparatus according to claim 1, further comprising a pair of slip rings disposed between both axial ends of said seal ring and said annular groove.
4. the slip ring includes a first surface that contacts the seal ring and a second surface that contacts a wall surface of the annular groove; 4. The rotary table apparatus according to claim 3, wherein a frictional force generated between the first surface and the seal ring is smaller than a frictional force generated between the second surface and a wall surface of the annular groove.
Citation Information
Patent Citations
Sealing device
JP1983018158U
Sealing device
JP2014062575A
Sealing structure
JP2017150594A
Seal and seal structure
JP2017155771A
Sealing device and sealing structure
JP2019065978A