Bearing assembly
The problem of radio wave propagation interference with the cooling mechanism was solved by using a non-metallic layer at the contact point between the bearing housing and the retaining cover, thus enabling wireless data transmission and cost control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NTN CORP
- Filing Date
- 2021-09-08
- Publication Date
- 2026-05-26
AI Technical Summary
Creating space within the housing around the bearing to facilitate radio wave propagation can easily interfere with the cooling mechanism, leading to reduced housing shape accuracy and increased costs.
Non-metallic materials, such as ceramics or resins, are used to form a non-metallic layer at the contact point between the housing and the retaining cover for data transmission of the wireless communication module, thus avoiding the need to create space inside the housing.
It enables wireless data transmission to the outside without interfering with the flow of cooling medium, maintaining the accuracy of the housing shape and reducing costs.
Smart Images
Figure CN116710666B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a bearing device that includes wireless communication functionality. Background Technology
[0002] For machine tools employing mechanisms such as rolling or oscillating mechanisms on the spindle, detection devices such as sensors can be attached to control or monitor the machine tool's status. In particular, in machines including rolling bearings, characteristics near the bearings inside the machine can be effectively detected. Therefore, various sensors, such as rotation sensors and temperature sensors, are preferably arranged near the bearings inside the machine.
[0003] Wires are traditionally used to transmit data detected by sensors. However, running wires inside a machine can interfere with other mechanisms within the machine or reduce the function of those mechanisms (e.g., reduced dimensional accuracy or shape). The ease of assembly of the machine can also be compromised, which can also be a factor in reduced productivity.
[0004] To address the aforementioned problems, for example, Japanese Patent Publication No. 2003-28151 (Patent Document 1) discloses a bearing device in which a wireless sensor with an antenna is connected to the outer ring of the bearing, and the data detected by the wireless sensor is wirelessly transmitted to the outside via radio waves. Since the bearing and peripheral components (housing, cover, etc.) are made of a metal (magnetic material) from which radio waves are unlikely to propagate, a space (hole or groove) is provided in the housing surrounding the accessory portion of the wireless sensor in the bearing device to facilitate the propagation of radio waves transmitted from the wireless sensor to the outside.
[0005] Reference List
[0006] Patent documents
[0007] Patent Document 1: Japanese Patent Application Publication No. 2003-28151 Summary of the Invention
[0008] Technical issues
[0009] As described above, in the bearing device disclosed in Japanese Patent Application Publication No. 2003-28151, a space (hole or groove) for promoting the propagation of radio waves is provided inside the housing arranged around the bearing.
[0010] However, inside the housing surrounding the bearing, there is usually another mechanism for cooling the bearing. When interference with other mechanisms occurs, the interior of the housing may not provide sufficient space. When complex shapes are provided inside the housing to avoid interference with other mechanisms, there are issues with poor housing shape accuracy or increased cost.
[0011] This disclosure is made to solve the above-mentioned problems, and its purpose is to provide a bearing device that can wirelessly transmit data to the outside without the need for providing space for promoting the propagation of radio waves inside the housing surrounding the bearing.
[0012] Technical means used to solve technical problems
[0013] (1) The bearing device according to this disclosure includes: a cylindrical housing accommodating a rotating body; a first bearing having an inner ring fixed to an outer surface of the rotating body and an outer ring fixed to an inner surface of the housing, the first bearing rotatably supporting the rotating body relative to the housing; a cover portion fitted to an inner surface of the housing, the cover portion contacting an axial end face of the housing and an axial end face of the outer ring; and a communication device arranged in a region opposite to the cover portion when the first bearing is inserted, the communication device performing wireless communication via electromagnetic waves. A non-metallic layer made of a non-metallic material is formed in at least one of the portion of the cover portion in contact with the housing, the portion of the housing in contact with the cover portion, the inner portion of the cover portion, and a member arranged between the inner surface of the cover portion and the outer surface of the rotating body.
[0014] (2) In one aspect, the communication device is arranged in the region between the first bearing and the second bearing, wherein the second bearing is arranged in a position opposite to the cover when the first bearing is inserted. The bearing assembly further includes a self-generating device arranged in the region between the first bearing and the second bearing, the self-generating device supplying power to the communication device.
[0015] (3) In one aspect, non-metallic materials are ceramics.
[0016] (4) In one aspect, the first bearing is an angular contact ball bearing.
[0017] (5) In one aspect, the rotating body is the spindle of the machine tool.
[0018] Invention Effects
[0019] According to this disclosure, a bearing device can be provided that is capable of wirelessly transmitting data to the outside without the need for space to facilitate the propagation of radio waves within the housing surrounding the bearing. Attached Figure Description
[0020] Figure 1 This is a cross-sectional view (number 1) showing the schematic structure of the bearing assembly.
[0021] Figure 2 This is a block diagram illustrating an exemplary construction of the communication module.
[0022] Figure 3This is a cross-sectional view (number 2) showing the schematic structure of the bearing assembly.
[0023] Figure 4 This is a cross-sectional view (number 3) showing the schematic structure of the bearing assembly. Detailed Implementation
[0024] Embodiments of the present disclosure will now be described with reference to the accompanying drawings. The same or corresponding elements in the drawings below have the same reference numerals, and their descriptions will not be repeated.
[0025] [First Implementation Method]
[0026] Figure 1 This is a cross-sectional view showing a schematic structure of the bearing device 1 according to the first embodiment.
[0027] Figure 1 The bearing assembly 1 shown is used, for example, as a spindle assembly with a built-in electric motor in a machine tool. In this case, the electric motor (not shown) is mounted on one end of the spindle 4 supported by the bearing assembly 1. Figure 1 (On the right side), a cutting tool, not shown, such as an end mill, is connected to the other end side. Figure 1 (Left side of the image). In this embodiment, the diameter of the spindle 4 is set to 70 mm, and the maximum rotational speed of the spindle 4 is set to 20,000 rpm.
[0028] The bearing assembly 1 includes a cylindrical housing 3 made of metal, a bearing 5 having two bearings 5a and 5b, a spacer 6 arranged between the bearings 5a and 5c, retaining covers 10 and 20 made of metal, and a communication module 140.
[0029] The main shaft 4 is located inside the housing 3 and is rotatably supported relative to the housing 3 by bearings 5a and 5b.
[0030] Bearing 5a is a rolling bearing, comprising an inner ring 5i a made of metal, an outer ring 5ga made of metal, a plurality of rolling elements Ta arranged between the inner ring 5i a and the outer ring 5ga, and a retainer Rta. The plurality of rolling elements Ta are held at intervals by the retainer Rta.
[0031] Bearing 5b is a rolling bearing comprising an inner ring 5ib made of metal, an outer ring 5gb made of metal, a plurality of rolling elements Tb arranged between the inner ring 5ib and the outer ring 5gb, and a retainer Rtb. The plurality of rolling elements Tb are held at intervals by the retainer Rtb.
[0032] The inner rings 5i a of bearing 5a and 5i b of bearing 5b, which are axially separated, are assembled to the spindle 4 by an interference fit (press fit).
[0033] The spacer 6 includes an inner ring spacer 6i and an outer ring spacer 6g. The inner ring spacer 6i is arranged between the inner rings 5i a and 5i b, while the outer ring spacer 6g is arranged between the outer rings 5ga and 5gb.
[0034] Angular contact ball bearings, deep groove ball bearings, or tapered roller bearings can be used as bearings 5a and 5b. Figure 1 The bearing assembly 1 shown includes angular contact ball bearings, wherein two bearings 5a and 5b are arranged in a back-to-back double bearing (DB) arrangement. The bearing arrangement is not limited to a back-to-back double bearing arrangement, but a face-to-face double bearing arrangement, for example, can also be applied.
[0035] Although a structure in which two bearings 5a and 5b support the spindle 4 has been shown and described, a structure in which more than two bearings support the spindle 4 can also be used.
[0036] The cooling medium flow path (not shown) is located inside the housing 3. By feeding the cooling medium through the cooling medium flow path in the housing 3, the bearings 5a and 5b can be cooled.
[0037] Each of the retaining covers 10 and 20 is an annular member that inhibits axial displacement of the housing 3 from the bearings 5a and 5b. The retaining cover 10 is fitted onto the inner surface of the housing 3, while the retaining cover 10 is positioned relative to one side of the housing 3 (in...). Figure 1 The axial end face of the cutting tool (located on the left side) and the axial end face of one side of the outer ring 5ga are in contact. The retaining cover 20 is fitted onto the inner surface of the housing 3, while the retaining cover 20 is also in contact with the other side of the housing 3 (where the cutting tool is located). Figure 1 In the middle, the axial end face of the right side of the motor and the axial end face of one side of the outer ring 5gb are in contact.
[0038] A communication module 140, including a sensor, is arranged between bearings 5a and 5b. More specifically, the communication module 140 is attached to the inside of the outer ring spacer 6g arranged between outer rings 5ga and 5gb. When viewed with bearing 5a as a reference, the communication module 140, with bearing 5a inserted, is arranged in the region opposite to the retaining cover 10. When viewed with bearing 5b as a reference, the communication module 140, with bearing 5b inserted, is arranged in the region opposite to the retaining cover 20.
[0039] Figure 2 This is a block diagram illustrating an exemplary configuration of the communication module 140 according to this embodiment. The communication module 140 includes a plurality of sensors (heat flux sensor 11 for measuring heat flux, temperature sensor 56 for measuring temperature, vibration sensor 57 for measuring vibration, and load sensor 59 for measuring preload) for controlling the spindle 4 or monitoring the bearing device 1, a communication device 141, and a power generation device 142.
[0040] The communication device 141 is connected to each sensor via wires and collects data indicating the detection results of each sensor. The communication device 141 can also wirelessly connect to each sensor and wirelessly collect data indicating the detection results of each sensor.
[0041] Communication device 141 transmits data collected from various sensors to an external device 200 located outside the bearing assembly 1 via electromagnetic wave wireless communication. Communication device 141, for example, conforms to... It uses the communication standard and can wirelessly transmit data indicating the detection results of each sensor to the external device 200 via radio waves in the 2.4 GHz band.
[0042] The power generation device 142 is connected to the communication device 141 and generates its own power to drive the communication device 141. For example, a thermoelectric element (Peltier element) that generates power based on the Seebeck effect can be used as the power generation device 142. When power is needed to drive individual sensors, the power generation device 142 can supply power to those sensors.
[0043] Although an example is described in this embodiment of modularizing the various sensors, communication devices 141 and power generation devices 142 into a single communication module 140 and arranging it in the outer ring spacer 6g, the various sensors, communication devices 141 and power generation devices 142 may be arranged separately without being modularized.
[0044] <About wireless data transmission>
[0045] As described above, the bearing device 1 according to this embodiment is configured such that the communication module 140 is arranged between the bearing 5a and the bearing 5b, and wirelessly transmits data indicating the detection results of each sensor to the outside.
[0046] However, since the bearing 5a, the housing 3 surrounding the bearing 5a, and the retaining covers 10 and 20 are all made of metal, it is difficult for radio waves to be transmitted from the communication module 140 to the outside of the bearing 5a and the outside of the bearing 5b.
[0047] If a space is provided inside the housing 3 in the radial direction to facilitate the propagation of radio waves, it may adversely lead to interference with the flow channels of the cooling medium in the housing 3, as well as consequently reduced accuracy of the shape of the housing 3 and increased cost.
[0048] In view of this drawback, in the bearing device 1 according to this embodiment, such as Figure 1As shown, a non-metallic layer 10a, made of ceramic as a non-metallic material, is provided in the portion of the retaining cover 10 that contacts the housing 3 (the portion of the retaining cover 10 that is fitted onto the inner surface and axial end face of one side of the housing 3). Similarly, a non-metallic layer 20a, also made of ceramic as a non-metallic material, is provided in the portion of the retaining cover 20 that contacts the housing 3 (the portion of the retaining cover 20 that is fitted onto the inner surface and axial end face of the other side of the housing 3). Examples of ceramics used for the non-metallic layers 10a and 20a include silicon nitride, alumina, and zirconium oxide.
[0049] Therefore, in the bearing device 1 according to this embodiment, data from the communication module 140 can be wirelessly transmitted to the outside of the bearing device 1 via non-metallic layers 10a and 20a provided in the portions of the retaining covers 10 and 20 that contact the housing 3. Thus, data can be wirelessly transmitted to the outside without the need for providing space to facilitate the propagation of radio waves inside the housing 3.
[0050] Furthermore, in the bearing assembly 1 according to this embodiment, similar to the communication device 141, a power generation device 142 that generates its own electricity to drive the communication device 141 is arranged between the bearings 5a and 5b. Therefore, the communication device 141 can be driven without a wire for supplying driving power to the communication device 141 located outside the bearing assembly 1.
[0051] In order to properly transmit data wirelessly from the communication module 140 to the outside, the non-metallic layers 10a, 20a and the communication module 140 are preferably arranged in a position as close to each other as possible. Figure 1 An example is shown where the metal layers 10a, 20a are disposed in a portion of the retaining covers 10, 20 in the circumferential direction. When the alignment between the non-metallic layers 10a, 20a and the communication module 140 makes it difficult to assemble the retaining covers 10, 20 to the inner surface of the housing 3, the non-metallic layers 10a, 20a may be configured to extend circumferentially over the entire retaining covers 10, 20.
[0052] The materials used for non-metallic layers 10a and 20a should be non-metallic materials that can transmit electromagnetic waves, and are not limited to ceramics as described above. For example, the materials used for non-metallic layers 10a and 20a can be resin materials such as polyetheretherketone (PEEK) or polyphenylene sulfide (PPS), or materials reinforced with carbon fiber or glass fiber, glass or rubber.
[0053] The non-metallic layer is not necessarily limited to the non-metallic layer provided at each opposite axial end of the housing 3. In other words, only one of the non-metallic layers 10a and 20a may be provided.
[0054] [Second Implementation]
[0055] Figure 3 This is a cross-sectional view showing a schematic structure of the bearing device 1A according to this second embodiment. In the bearing device 1A, a non-metallic layer, as described above, is provided in the housing 3 instead of the retaining covers 10 and 20. Specifically, the bearing device 1A is as described above. Figure 1 The housing 3 and retaining covers 10, 20 of the bearing assembly 1 shown have been changed to a bearing assembly with housing 3A and retaining covers 10A, 20A. Furthermore, the bearing assembly 1A is structurally identical to the bearing assembly 1 described above.
[0056] The retaining covers 10A and 20A are retaining covers from which the non-metallic layers 10a and 20a have been removed, respectively, from the retaining covers 10 and 20 as described above.
[0057] Non-metallic layers 3a and 3b, made of non-metallic material, are respectively provided in the portions of the housing 3A that contact the retaining covers 10A and 20A. Specifically, non-metallic layer 3a is provided in a portion of the inner surface and axial end of one side of the housing 3A, and non-metallic layer 3b is provided in a portion of the inner surface and axial end of the other side of the housing 3A.
[0058] Therefore, in the bearing device 1A according to this second embodiment, data from the communication module 140 can be wirelessly transmitted to the outside of the bearing device 1A through the non-metallic layers 3a and 3b provided at opposite ends of the housing 3. Thus, data can be wirelessly transmitted to the outside without providing space for promoting the propagation of radio waves inside the housing 3A.
[0059] [Third Implementation Method]
[0060] Figure 4 This is a cross-sectional view showing a schematic structure of the bearing device 1B according to this third embodiment. The bearing device 1B is as described above. Figure 3 The bearing assembly 1A shown has a housing 3A and a retaining cover 10A, which have been changed to a housing 3 and a retaining cover 10B and an inner ring spacer 32 have been added. Furthermore, the bearing assembly 1B is structurally identical to the bearing assembly 1A as described above. The housing 3 of the bearing assembly 1B is the same as the housing 3 of the bearing assembly 1 as described above.
[0061] In the bearing device 1B according to the third embodiment, a bend 30 for preventing foreign objects (e.g., coolant used for operation or debris generated during operation) from entering from the outside of the spindle 4 is provided at the tip of the spindle 4.
[0062] The bend 30 is formed by the inner portion 31 of the retaining cover 10B and an inner ring spacer 32 disposed between the inner surface of the retaining cover 10A and the outer surface of the spindle 4 and fitted to the spindle 4. Resin material is used as the material for the inner portion 31 of the retaining cover 10B and the inner ring spacer 32 forming the bend 30. In other words, the bend 30 forms a non-metallic layer.
[0063] Therefore, in the bearing device 1B according to this third embodiment, data from the communication module 140 can be wirelessly transmitted to the outside of the bearing device 1B through the bend 30 (non-metallic layer). Thus, data can be wirelessly transmitted to the outside without providing space for promoting the propagation of radio waves within the housing 3A.
[0064] although Figure 4 An example is shown where a non-metallic layer is formed in both the inner portion 31 and the inner ring spacer 32 of the retaining cover 10B forming the bend 30, but the non-metallic layer may also be formed in only one of the inner portion 31 and the inner ring spacer 32 of the retaining cover 10A.
[0065] It should be understood that the embodiments disclosed herein are illustrative and non-limiting in all respects. The scope of this disclosure is limited by the claims rather than by the description of the embodiments described above, and is intended to be included within the scope of the claims and to have the same meaning as any variation thereof.
[0066] List of reference numerals
[0067] 1. Bearing assembly 1A, 1B; 3. Housing 3A; Non-metallic layers 3a, 3b, 10a, 20a; 4. Main shaft; 5. Bearings 5a, 5b; Outer rings 5ga, 5gb; Inner rings 5i a, 5i b; 6. Spacer; Outer ring spacer 6g; Inner ring spacers 6i, 32; 10. Retaining caps 10, 10A, 10B, 20, 20A; 11. Heat flux sensor; 30. Bend section; 31. Inner part; 56. Temperature sensor; 57. Vibration sensor; 59. Load sensor; 140. Communication module; 141. Communication device; 142. Power generation device; 200. External device; Retaining elements Rta, Rtb; Rolling elements Ta, Tb.
Claims
1. A bearing assembly, comprising: A cylindrical shell that houses the rotating body; A first bearing having an inner ring fixed to the outer surface of the rotating body and an outer ring fixed to the inner surface of the housing, the first bearing rotatably supporting the rotating body relative to the housing; A cover portion is fitted onto the inner surface of the housing, and the cover portion is in contact with the axial end face of the housing and the axial end face of the outer ring. as well as A communication device, wherein the communication device is arranged in a region opposite to the cover when the first bearing is inserted, the communication device performs wireless communication via electromagnetic waves, wherein... A non-metallic layer made of non-metallic material is formed in at least one of the portion of the cover that contacts the housing, the portion of the housing that contacts the cover, the inner portion of the cover, and a component disposed between the inner surface of the cover and the outer surface of the rotating body.
2. The bearing device as described in claim 1, characterized in that, The communication device is arranged in the area between the first bearing and the second bearing, with the second bearing positioned opposite to the cover when the first bearing is inserted into it. The bearing assembly also includes a self-generating device disposed between the first bearing and the second bearing, the self-generating device supplying power to the communication device.
3. The bearing device as described in claim 1 or 2, characterized in that, The non-metallic material is ceramic.
4. The bearing device as described in claim 1, characterized in that, The first bearing is an angular contact ball bearing.
5. The bearing device as claimed in claim 1, characterized in that, The rotating body is the spindle of the machine tool.