JP7346107B2 - Bearing device and spindle device - Google Patents

Description

The present invention relates to a bearing device and a spindle device.

Patent Document 1 (Japanese Unexamined Patent Publication No. 2012-37013) describes a bearing device. The bearing device described in Patent Document 1 includes a housing, a shaft, a first rolling bearing, a second rolling bearing, an inner ring spacer, an outer ring spacer, a temperature sensor, and wiring.

The housing has a first end and a second end opposite to the first end along the direction in which the shaft extends. The housing has an inner peripheral surface and an outer peripheral surface. A groove is formed in the inner circumferential surface and is recessed toward the outer circumferential surface. The groove extends from the first end toward the second end.

The shaft is housed within the housing. The first rolling bearing and the second rolling bearing rotatably support the shaft within the housing. The first rolling bearing has a first inner ring attached to the shaft and a first outer ring attached to the inner peripheral surface of the housing. The second rolling bearing has a first inner ring attached to the shaft and a first outer ring attached to the inner peripheral surface of the housing. The second rolling bearing is located further away from the first end than the first rolling bearing in the extending direction of the shaft.

The inner ring spacer is attached to the shaft. The inner ring spacer is sandwiched between the first inner ring and the second inner ring in the extending direction of the shaft. The outer ring spacer is attached to the inner peripheral surface of the housing. The outer ring spacer is sandwiched between the first outer ring and the second outer ring in the extending direction of the shaft. The temperature sensor is an infrared sensor for detecting the temperature of the first rolling bearing and the second rolling bearing in a non-contact manner. The temperature sensor is attached to the outer ring spacer.

The wiring is connected to the temperature sensor at one end and to the outside of the bearing device at the other end. The wiring is passed through a groove formed in the inner peripheral surface of the housing.

Japanese Patent Application Publication No. 2012-37013

In the bearing device described in Patent Document 1, the temperature sensor and the outside of the bearing device are connected by wiring, so the wiring gets in the way during assembly, reducing work efficiency when assembling the bearing device.

The present invention has been made in view of the problems of the prior art as described above. More specifically, the present invention provides a bearing device and a spindle device that can improve workability during assembly.

A bearing device according to one aspect of the present invention includes a housing having an inner circumferential surface and an outer circumferential surface, a shaft housed in the housing, a rolling bearing rotatably supporting the shaft in the housing, and an inner circumferential surface. A non-rotating member attached to the peripheral surface, a sensor attached to the non-rotating member and detecting the state of the rolling bearing, a first wiring electrically connected to the sensor and drawn out from the non-rotating member, and a hollow member. Equipped with. The housing has a first end and a second end opposite the first end. The non-rotating member is located closer to the second end than the rolling bearing. A groove that is depressed toward the outer circumferential surface is formed on the inner circumferential surface. The groove extends from the first end toward the second end. A hollow member is inserted into the groove. The hollow member has a third end attached to the non-rotating member and a fourth end opposite the third end. The first wiring is passed through the inside of the hollow member from the third end toward the fourth end.

The above bearing device may further include a lid member. The rolling bearing may have an outer ring attached to the inner peripheral surface. The lid member may be attached to the first end so as to contact the outer ring from the first end side. A through hole may be formed in the lid member. A hollow member may be inserted into the through hole.

The above bearing device may further include a connector electrically connected to the first wiring. A connector may be attached to the fourth end.

The above bearing device may further include a lid member. The rolling bearing may have an outer ring attached to the inner peripheral surface. The lid member may be attached to the first end so as to contact the outer ring from the first end side. A through hole may be formed in the lid member. The first wiring may be passed through the through hole.

The bearing device described above may further include a second wiring electrically connected to the sensor and drawn out from the non-rotating member, a first communication section, and a second communication section. The first wiring may be a signal wiring that transmits an output signal from the sensor. The second wiring may be a power supply wiring that supplies power to drive the sensor. The first wiring and the second wiring may be electrically connected to the first communication section. The first communication unit may be configured to wirelessly transmit the output signal to the second communication unit. The second communication unit may be configured to wirelessly supply power to the first communication unit.

The bearing device further includes a third communication section electrically connected to the first wiring, an antenna, and a generator that supplies power generated by rotation of the shaft to the sensor and the third communication section. Good too. The first wiring may be a signal wiring that transmits an output signal from the sensor. The third communication unit may be configured to wirelessly transmit the output signal.

In the above bearing device, the non-rotating member may be an outer ring spacer. In the above bearing device, the non-rotating member may be a holding member that holds a spring that applies constant pressure preload to the rolling bearing. In the above bearing device, the sensor may be a heat flux sensor that detects heat flux from the shaft side to the housing side.

A spindle device according to one aspect of the present invention includes the above-described bearing device and a motor that rotates a shaft.

According to the bearing device and spindle device according to one aspect of the present invention, workability during assembly can be improved.

1 is a cross-sectional view of a spindle device 100. FIG. FIG. 2 is an enlarged view of region II in FIG. 1; FIG. 3 is a sectional view taken along line III-III in FIG. 2; 3 is a sectional view of a bearing device 30 in a spindle device 200. FIG. 3 is a sectional view of a bearing device 30 in a spindle device 300. FIG. 3 is a sectional view of a bearing device 30 in a spindle device 400. FIG. 3 is a cross-sectional view of a bearing device 30 in a spindle device 500. FIG.

Details of the embodiments will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and overlapping descriptions will not be repeated.

(First embodiment)
Below, a spindle device (hereinafter referred to as "spindle device 100") according to a first embodiment will be described.

<Overall configuration of spindle device 100>
FIG. 1 is a cross-sectional view of a spindle device 100. FIG. 2 is an enlarged view of region II in FIG. FIG. 3 is a sectional view taken along line III-III in FIG. Note that in FIG. 3, illustrations of members unnecessary for explanation are omitted. As shown in FIGS. 1 to 3, the spindle device 100 includes a shaft 10, an outer cylinder 20, a bearing device 30, a motor 60, an end member 70, and a bearing device 80. The spindle device 100 is, for example, a built-in motor spindle device for a machine tool.

<Configuration of shaft 10>
The shaft 10 has a rotation center axis A. In the following, the direction along the rotation center axis A is called the axial direction, the direction along the circumference passing through the rotation center axis A is called the circumferential direction, and the direction passing through the rotation center axis A and orthogonal to the axial direction is called the circumferential direction. This is called the radial direction.

The shaft 10 has a first end 10a and a second end 10b. The first end 10a and the second end 10b are ends of the shaft 10 in the axial direction. A cutting tool such as an end mill is attached to the first end 10a. The second end 10b is the end opposite to the first end 10a.

The shaft 10 has a first shaft portion 11 , a second shaft portion 12 , and a tip portion 13 . The first shaft portion 11 extends from the second end 10b toward the first end 10a. The tip portion 13 is located at the first end 10a. The second shaft portion 12 extends to connect the first shaft portion 11 and the tip portion 13.

The outer diameter of the shaft 10 in the first shaft portion 11 is smaller than the outer diameter of the shaft in the second shaft portion 12. The outer diameter of the second shaft portion 12 is smaller than the outer diameter of the end of the tip portion 13 on the second shaft portion 12 side. That is, steps are formed on the outer circumferential surface of the shaft 10 at the boundary between the first shaft portion 11 and the second shaft portion 12 and at the boundary between the second shaft portion 12 and the tip portion 13.

<Configuration of outer cylinder 20>
The outer cylinder 20 has a cylindrical shape extending along the axial direction. The outer cylinder 20 has a first end 20a and a second end 20b in the axial direction. The first end 20a is the end of the outer cylinder 20 located on the first end 10a side. The second end 20b is the end of the outer tube 20 located on the second end 10b side. That is, the second end 20b is the end opposite to the first end 20a. The outer cylinder 20 has an inner peripheral surface 20c.

<Configuration of bearing device 30>
The bearing device 30 includes a housing 31, a rolling bearing 32, a rolling bearing 33, an inner ring spacer 34, an outer ring spacer 35, a cover member 36, a nut 37, a spacer 38, a sensor 39, and wiring. 40, wiring 41, and hollow member 42. Note that the shaft 10 constitutes a part of the bearing device 30.

The housing 31 has a cylindrical shape extending along the axial direction. The housing 31 has a first end 31a and a second end 31b in the axial direction. The first end 31a is the end of the housing 31 on the first end 10a side. The second end 31b is the end of the housing 31 on the second end 10b side. That is, the second end 31b is the end opposite to the first end 31a. The shaft 10 is housed inside the housing 31.

The housing 31 is housed inside the outer cylinder 20. More specifically, the housing 31 has an inner circumferential surface 31c and an outer circumferential surface 31d, and is arranged such that the outer circumferential surface 31d is in contact with the inner circumferential surface 20c.

A groove 31ca is formed in the inner peripheral surface 31c. In the groove 31ca, the inner peripheral surface 31c is depressed toward the outer peripheral surface 31d. The groove 31ca extends from the first end 31a toward the second end 31b. A groove 31da is formed in the outer peripheral surface 31d. The groove 31da is formed in a spiral shape around the rotation center axis A. A flow path through which a coolant for cooling the bearing device 30 flows is defined by the groove 31da and the inner circumferential surface 20c.

The rolling bearing 32 is, for example, an angular ball bearing. The rolling bearing 32 rotatably supports the shaft 10 within the housing 31. The rolling bearing supports the load in the radial direction (radial direction) and the load in the thrust direction (axial direction) acting on the shaft 10.

The rolling bearing 32 has an inner ring 32a, an outer ring 32b, rolling elements 32c, and a cage 32d. The inner ring 32a is attached to the shaft 10 (second shaft portion 12). The outer ring 32b is attached to the inner peripheral surface 31c. The inner ring 32a is in contact with a step formed on the outer peripheral surface of the shaft 10 at the boundary between the second shaft portion 12 and the tip portion 13 from the second end 10b side. The outer peripheral surface of the inner ring 32a and the inner peripheral surface of the outer ring 32b are opposed to each other. The rolling elements 32c are arranged between the inner ring 32a and the outer ring 32b. The number of rolling elements 32c is plural. The cage 32d is disposed between the inner ring 32a and the outer ring 32b, and holds the rolling elements 32c. The cage 32d maintains the distance between the two rolling elements 32c adjacent to each other in the circumferential direction within a certain range.

The rolling bearing 33 is, for example, an angular ball bearing. The rolling bearing 33 rotatably supports the shaft 10 within the housing 31. The rolling bearing supports the load in the radial direction and the load in the thrust direction acting on the shaft 10. The rolling bearing 33 has an inner ring 33a, an outer ring 33b, rolling elements 33c, and a cage 33d. The inner ring 33a is attached to the shaft 10 (second shaft portion 12). The outer ring 33b is attached to the inner peripheral surface 31c. The outer peripheral surface of the inner ring 33a and the inner peripheral surface of the outer ring 33b are opposed to each other. The rolling elements 33c are arranged between the inner ring 33a and the outer ring 33b. The number of rolling elements 33c is plural. The cage 33d is disposed between the inner ring 33a and the outer ring 33b, and holds the rolling elements 33c. The cage 33d maintains the distance between two rolling elements 33c adjacent to each other in the circumferential direction within a certain range.

The rolling bearing 32 and the rolling bearing 33 are spaced apart from each other in the axial direction. The rolling bearing 32 is located closer to the first end 10a than the rolling bearing 33. The rolling bearing 32 and the rolling bearing 33 are in a back-to-back (DB) combination. The rolling bearing 32 and the rolling bearing 33 may be a face-to-face (DF) combination.

Inner ring spacer 34 is attached to shaft 10 (second shaft portion 12). The inner ring spacer 34 is in contact with the inner ring 32a at the end on the first end 10a side, and is in contact with the inner ring 33a at the end on the second end 10b side. To put this in another perspective, the inner ring spacer 34 is sandwiched between the inner ring 32a and the inner ring 33a in the axial direction. The inner ring spacer 34 has a cylindrical shape extending along the axial direction.

The outer ring spacer 35 is attached to the inner peripheral surface 31c. Therefore, the outer ring spacer 35 is a non-rotating member. Here, the term "non-rotating member" refers to a member that does not rotate with respect to the housing 31 (that is, is attached to the housing 31). The outer ring spacer 35 is in contact with the outer ring 32b at the end on the first end 10a side, and is in contact with the outer ring 33b at the end on the second end 10b side. To put this in another perspective, the outer ring spacer 35 is sandwiched between the outer ring 32b and the outer ring 33b in the axial direction. The outer ring spacer 35 has a cylindrical shape extending along the axial direction. The outer peripheral surface of the outer ring spacer 35 is in contact with the inner peripheral surface 31c. A part of the outer peripheral surface of the outer ring spacer 35 is exposed from the groove 31ca.

The lid member 36 has a cylindrical portion 36a and a flange portion 36b. The cylindrical portion 36a has a cylindrical shape extending along the axial direction. The outer circumferential surface of the cylindrical portion 36a is in contact with the inner circumferential surface 31c. The cylindrical portion 36a holds the outer ring 32b between the outer ring spacer 35 and the outer ring spacer 35 in the axial direction. The flange portion 36b protrudes from the end of the cylindrical portion 36a opposite to the outer ring 32b in a plane perpendicular to the axial direction. The flange portion 36b is fixed to the first end 31a. Thereby, the lid member 36 is attached to the first end 31a.

A through hole 36c is formed in the lid member 36. The through hole 36c passes through the lid member 36. More specifically, the through hole 36c passes through the flange portion 36b along the axial direction.

The nut 37 is attached (threaded) to the shaft 10. The nut 37 is located closer to the second end 10b than the rolling bearing 33 (inner ring 33a) in the axial direction. Spacer 38 is attached to shaft 10. The spacer 38 is in contact with the inner ring 33a at the end on the first end 10a side, and is in contact with the nut 37 at the end on the second end 10b side. To put this in another perspective, the spacer 38 is sandwiched between the inner ring 33a and the nut 37 in the axial direction. By moving the nut 37 toward the first end 10a, a preload is applied to the rolling bearing 32 and the rolling bearing 33. This preload is a fixed position preload.

The sensor 39 is attached to the outer ring spacer 35. More specifically, the sensor 39 is attached to the inner peripheral surface of the outer ring spacer 35. The sensor 39 is, for example, a heat flux sensor. The sensor 39 is arranged to face a rotating member (inner ring 32a, inner ring 33a, or inner ring spacer 34) attached to the shaft 10. Thereby, the heat flux from the shaft 10 side to the housing 31 side can be detected. When an abnormality occurs in the rolling bearing 32 (rolling bearing 33), a difference occurs between the temperature of the inner ring 32a (inner ring 33a) and the temperature of the outer ring 32b (outer ring 33b). Prior to this temperature difference, the heat flux from the shaft 10 side to the housing 31 side changes, so by detecting the above heat flux with the sensor 39, abnormalities in the rolling bearing 32 (rolling bearing 33) can be quickly detected. Can be detected (early). The sensor 39 may be a sensor other than a heat flux sensor (for example, a temperature sensor).

Wiring 40 is electrically connected to sensor 39. The wiring 40 passes through the inside of the outer ring spacer 35 and is drawn out to the outside of the outer ring spacer 35. More specifically, the wiring 40 is drawn out from the outer peripheral surface of the outer ring spacer 35 exposed from the groove 31ca. The output signal from sensor 39 is output via wiring 40.

The bearing device 30 may include a circuit board (not shown) attached to the outer ring spacer 35. An amplifier (instrumentation amplifier) is mounted on this circuit board. The wiring 40 may be drawn out from the outer ring spacer 35 by being electrically connected to this circuit board. In this case, the output signal of the sensor 39 is output as an amplified analog signal.

A microcontroller may be mounted on the above circuit board. In this case, the output signal from the sensor 39 is converted into a digital signal in the ADC circuit (Analog to Digital Converter) circuit of the microcontroller, and the output signal is converted into a digital signal in the microcontroller's communication circuit, for example, in compliance with RS422, CAN (Controller Area Network), etc. is converted into a serial communication signal. Thereby, even if the number of sensors 39 increases, it is possible to suppress an increase in the number of wiring lines.

Wiring 41 is electrically connected to sensor 39. The wiring 41 passes through the inside of the outer ring spacer 35 and is drawn out to the outside of the outer ring spacer 35. More specifically, the wiring 41 is drawn out from the outer peripheral surface of the outer ring spacer 35 exposed from the groove 31ca. Electric power for driving the sensor 39 is supplied from the wiring 41 .

The hollow member 42 is a tubular member that is hollow inside. The hollow member 42 has a first end 42a and a second end 42b. The hollow member 42 is attached to the outer ring spacer 35 at the first end 42a. More specifically, the first end 42a is attached to the outer peripheral surface of the outer ring spacer 35 exposed from the groove 31ca. The wiring 40 and the wiring 41 are passed through the inside of the hollow member 42 from the first end 42a toward the second end 42b. The hollow member 42 is inserted into the groove 31ca (arranged within the groove 31ca). The hollow member 42 is further inserted into the through hole 36c. Wiring 40 and wiring 41 are drawn out of the bearing device 30 from the second end 42b.

Note that the hollow member 42 does not need to be inserted into the through hole 36c. In this case, the wiring 40 and wiring 41 drawn out from the second end 42b are passed through the through hole 36c and drawn out to the outside of the bearing device 30.

<Configuration of motor 60>
As shown in FIG. 1, the motor 60 includes a cylindrical member 61, a rotor 62, and a stator 63. The cylindrical member 61 is attached to the shaft 10. The end of the cylindrical member 61 on the first end 10a side is in contact with a step formed on the outer peripheral surface 10c at the boundary between the first shaft section 11 and the second shaft section 12.

The rotor 62 is attached to the cylindrical member 61. The stator 63 is attached to the inner peripheral surface 20c so as to face the rotor 62. By sequentially switching the direction of the current flowing through the stator 63 by an inverter circuit, a rotational force is generated on the rotor 62, and the shaft 10 rotates around the rotation center axis A due to the rotational force.

<Configuration of end member 70>
The end member 70 is attached to the second end 20b. A through hole 71 is formed in the end member 70. The through hole 71 penetrates the end member 70 along the axial direction. The shaft 10 is inserted through the through hole 71 .

<Configuration of bearing device 80>
The bearing device 80 includes a rolling bearing 81, an inner ring pressing member 82, a positioning member 83, a positioning member 84, and a nut 85.

The rolling bearing 81 is, for example, a cylindrical roller bearing. The rolling bearing 81 supports the shaft 10 so as to be rotatable around the rotation center axis A. The rolling bearing 81 supports the load acting on the shaft 10 in the radial direction. The inner ring of the rolling bearing 81 is attached to the shaft 10, and the outer ring of the rolling bearing 81 is attached to the end member 70 (more specifically, the inner wall surface of the through hole 71). The inner ring of the rolling bearing 81 is in contact with the end of the cylindrical member 61 on the second end 10b side.

The inner ring pressing member 82 is attached to the shaft 10. The inner ring pressing member 82 is in contact with the inner ring of the rolling bearing 81 from the second end 10b side. That is, the inner ring of the rolling bearing 81 is sandwiched between the cylindrical member 61 and the inner ring pressing member 82 in the axial direction.

The positioning member 83 is attached to the end member 70 and contacts the outer ring of the rolling bearing 81 from the second end 10b side. The positioning member 84 is attached to the end member 70 and is in contact with the outer ring of the rolling bearing 81 from the first end 10a side. That is, the outer ring of the rolling bearing 81 is sandwiched between the positioning member 83 and the positioning member 84 in the axial direction. Thereby, when the shaft 10 expands or contracts, the inner ring of the rolling bearing 81 slides in the axial direction along the through hole 71 of the end member 70 integrally with the shaft 10.

The nut 85 is attached (threaded) to the shaft 10. The nut 85 is arranged to sandwich the inner ring pressing member 82 between the inner ring of the rolling bearing 81 in the axial direction. That is, the inner ring holding member 82 is prevented from coming off the shaft 10 by the nut 85.

<Effects of bearing device 30>
In assembling the bearing device 30, first, the rolling bearing 32, the inner ring spacer 34, the outer ring spacer 35, the rolling bearing 33, and the spacer 38 are sequentially attached to the shaft 10. At this stage, the sensor 39 and the hollow member 42 are attached to the outer ring spacer 35, and the wiring 40 and the wiring 41 are passed through the hollow member 42. In assembling the bearing device 30, secondly, the nut 37 is screwed onto the shaft 10. As a result, preload is applied to the rolling bearing 32 and the rolling bearing 33.

In assembling the bearing device 30, thirdly, the shaft 10 to which the rolling bearing 32, the inner ring spacer 34, the outer ring spacer 35, the rolling bearing 33, the nut 37, and the spacer 38 are attached is inserted into the housing 31. . At this time, the hollow member 42 is inserted into the groove 31ca. In assembling the bearing device 30, fourthly, the lid member 36 is attached to the first end 31a. At this time, the hollow member 42 is inserted into the through hole 36c. By inserting the hollow member 42 into the groove 31ca and the through hole 36c, the wiring 40 and the wiring 41 are drawn out to the outside of the bearing device 30.

In this way, since the bearing device 30 is assembled while the wiring 40 and the wiring 41 are housed in the hollow member 42, there is no need to route long wiring during assembly, and ease of assembly can be improved.

(Second embodiment)
A spindle device (hereinafter referred to as "spindle device 200") according to a second embodiment will be described below. Here, the points that are different from the spindle device 100 will be mainly explained, and redundant explanations will not be repeated.

The spindle device 100 includes a shaft 10, an outer cylinder 20, a bearing device 30, a motor 60, an end member 70, and a bearing device 80. In this respect, spindle device 200 has in common with spindle device 100.

FIG. 4 is a sectional view of the bearing device 30 in the spindle device 200. As shown in FIG. 4 , the spindle device 200 differs from the spindle device 100 in that the bearing device 30 further includes a connector 43 .

Connector 43 is electrically connected to wiring 40 and wiring 41. Connector 43 is preferably attached to second end 42b. Connector 43 is electrically connected to cable 44 . More specifically, the cable 44 has a socket 44a, and is electrically connected to the connector 43 by fitting the socket 44a into the connector 43. Cable 44 is electrically connected to a control device (not shown) and a power source (not shown).

In the spindle device 200, it is not necessary to extend the wiring 40 and the wiring 41 from the second end 42b for a long time in order to connect the bearing device 30 with the outside, so that assembly efficiency can be further improved.

(Third embodiment)
Below, a spindle device (hereinafter referred to as "spindle device 300") according to a third embodiment will be described. Here, the points that are different from the spindle device 100 will be mainly explained, and redundant explanations will not be repeated.

The spindle device 300 includes a shaft 10, an outer cylinder 20, a bearing device 30, a motor 60, an end member 70, and a bearing device 80. In this respect, spindle device 300 has in common with spindle device 100.

FIG. 5 is a sectional view of the bearing device 30 in the spindle device 300. As shown in FIG. 5, the spindle device 300 differs from the spindle device 100 in that the bearing device 30 further includes a communication section 45 and a communication section 46.

The communication unit 45 is electrically connected to the wiring 40 and the wiring 41. The communication unit 46 is arranged apart from the communication unit 45. The communication unit 46 is electrically connected to a cable 44, and is electrically connected to a control device (not shown) and a power source (not shown) via the cable 44. The communication unit 45 has a built-in power receiving coil, and the communication unit 46 has a built-in power transmitting coil.

The output signal of the sensor 39 is supplied to the communication unit 45 via the wiring 40 . The communication unit 45 wirelessly transmits the output signal from the sensor 39 to the communication unit 46 . The communication unit 46 wirelessly supplies power to the communication unit 45 via the power reception coil of the communication unit 45 using the transmission coil. The power supplied to the communication unit 45 is supplied to the sensor 39 via the wiring 41.

In the spindle device 300, it is not necessary to extend the wiring 40 and the wiring 41 from the second end 42b for a long time in order to connect the bearing device 30 with the outside, so that assembly efficiency can be further improved.

(Fourth embodiment)
A spindle device (hereinafter referred to as "spindle device 400") according to a fourth embodiment will be described below. Here, the points that are different from the spindle device 100 will be mainly explained, and redundant explanations will not be repeated.

The spindle device 400 includes a shaft 10, an outer cylinder 20, a bearing device 30, a motor 60, an end member 70, and a bearing device 80. In this respect, spindle device 400 has in common with spindle device 100.

FIG. 6 is a sectional view of the bearing device 30 in the spindle device 400. As shown in FIG. 6, the spindle device 400 differs from the spindle device 100 in that the bearing device 30 further includes a generator 47, a communication section 48, and an antenna 49.

The generator 47 is, for example, a claw pole type generator. The generator 47 has a magnetic ring 47a and a magnetic yoke 47b. The magnetic ring 47a is magnetized with N poles and S poles alternately along the circumferential direction. The magnetic ring 47a is attached to the outer peripheral surface of the inner ring spacer 34. The magnetic yoke 47b has a built-in coil. The magnetic yoke 47b is attached to the inner peripheral surface of the outer ring spacer 35 so as to face the magnetic ring 47a.

A notch 35a may be formed in the inner peripheral surface of the outer ring spacer 35. The inner diameter at the cutout portion 35a is smaller than the inner diameter at other portions other than the cutout portion 35a. The magnetic yoke 47b may be attached to the notch 35a. A ring member 35b may be attached to a portion of the notch 35a where the magnetic yoke 47b is not attached.

The generator 47 generates electricity by rotating the shaft 10. More specifically, as the shaft 10 rotates, the magnetic ring 47a rotates with respect to the magnetic yoke 47b. As the magnetic ring 47a rotates, current flows through a coil built into the magnetic yoke 47b, thereby generating electricity.

However, the generator 47 is not limited to a claw-pole type generator, and may be any generator that generates power by rotating the shaft 10. For example, the generator 47 may be a Peltier device. This Peltier element is attached to the inner peripheral surface of the outer ring spacer 35 so as to face the outer peripheral surface of the inner ring spacer 34. As the shaft 10 rotates, a temperature difference occurs between the inner ring spacer 34 and the outer ring spacer 35. Since an electromotive force is generated in the Peltier element due to this temperature difference, power is generated as the shaft 10 rotates.

The output signal from the sensor 39 is wirelessly transmitted from the communication unit 48 via the antenna 49 . The communication unit 48 and the sensor 39 may be driven by electric power generated by the generator 47. In the spindle device 400, since there is no cable drawn out from the bearing device 30, the ease of assembly can be further improved.

A spindle device (hereinafter referred to as "spindle device 500") according to a fifth embodiment will be described below. Here, the points that are different from the spindle device 100 will be mainly explained, and redundant explanations will not be repeated.

The spindle device 500 includes a shaft 10, an outer cylinder 20, a bearing device 30, a motor 60, an end member 70, and a bearing device 80. In this respect, spindle device 500 has in common with spindle device 100.

FIG. 7 is a sectional view of the bearing device 30 in the spindle device 500. As shown in FIG. 7, the spindle device 500 has the following features: the bearing device 30 does not have an inner ring spacer 34 and an outer ring spacer 35, and the bearing device 30 further includes a nut 50, a spacer 51, and a preload portion 52. This differs from the spindle device 100 in that it does so.

The shaft 10 in the spindle device 500 has a stepped portion 14 on its outer peripheral surface. The outer diameter of the shaft 10 at the stepped portion 14 is larger than the outer diameter of the shaft 10 at the portion other than the stepped portion 14. The stepped portion 14 is in contact with the inner ring 32a at the end on the first end 10a side, and is in contact with the inner ring 33a at the end on the second end 10b side. That is, the stepped portion 14 is sandwiched between the inner ring 32a and the inner ring 33a in the axial direction.

The housing 31 of the bearing device 30 in the spindle device 500 has a stepped portion 31e on the inner peripheral surface 31c. The inner diameter of the housing 31 at the stepped portion 31e is smaller than the inner diameter of the housing 31 at other portions than the stepped portion 31e. The stepped portion 31e is in contact with the outer ring 33b at the end on the second end 31b side, and is in contact with the spring holder 52b at the end on the first end 31a side.

The nut 50 is attached (threaded) to the shaft 10. The nut 50 is located closer to the first end 10a than the rolling bearing 32 (inner ring 32a). The spacer 51 is attached to the shaft 10. The spacer 51 is in contact with the nut 50 at the end on the first end 10a side, and is in contact with the inner ring 32a at the end on the second end 10b side. That is, the spacer 51 is sandwiched between the nut 50 and the inner ring 32a in the axial direction.

The preload portion 52 includes a ring 52a, a spring holder 52b, and a spring 52c. The ring 52a is attached to the inner peripheral surface 31c. The ring 52a is in contact with the outer ring 32b from the second end 10b side. The spring holder 52b is attached to the inner peripheral surface 31c. Therefore, the spring holder 52b is a non-rotating member. The spring holder 52b is arranged closer to the second end 10b than the ring 52a. A sensor 39 is attached to the inner peripheral surface of the spring holder 52b. A wiring 40 and a wiring 41 are drawn out from the spring holder 52b. A hollow member 42 is attached to the spring holder 52b. The spring 52c biases the ring 52a along the direction from the second end 10b to the first end 10a by being held by the spring holder 52b. As a result, a constant preload is applied to the rolling bearing 32 and the rolling bearing 33.

Similarly to the bearing device 30 in the spindle device 100, the bearing device 30 in the spindle device 500 is assembled with the wiring 40 and the wiring 41 housed in the hollow member 42, so long wiring is not required during assembly. There is no need to handle it, and ease of assembly can be improved.

Although the embodiments of the present invention have been described above, the embodiments described above can be modified in various ways. Moreover, the scope of the present invention is not limited to the above-described embodiments. The scope of the present invention is indicated by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

The embodiments described above are particularly advantageously applied to bearing devices and spindle devices used in machine tools.

Reference Signs List 10 shaft, 10a first end, 10b second end, 10c outer peripheral surface, 11 first shaft portion, 12 second shaft portion, 13 tip portion, 14 step portion, 20 outer cylinder, 20a first end, 20b second end , 20c inner circumference, 30, 80 bearing device, 31 housing, 31c inner circumference, 31ca groove, 31d outer circumference, 31da groove, 31e step, 32 rolling bearing, 32a inner ring, 32b outer ring, 32c rolling element, 32d holding container, 33 rolling bearing, 33a inner ring, 33b outer ring, 33c rolling element, 33d retainer, 34 inner ring spacer, 35 outer ring spacer, 35a notch, 35b ring member, 36 lid member, 36a cylindrical part, 36b flange part , 36c through hole, 37 nut, 38 spacer, 39 sensor, 40 wiring, 41 wiring, 42 hollow member, 42a first end, 42b second end, 43 connector, 44 cable, 44a socket, 45 communication section, 46 communication Part, 47 Generator, 47a Magnetic ring, 47b Magnetic yoke, 48 Communication part, 49 Antenna, 50 Nut, 51 Spacer, 52 Preload part, 52a Ring, 52b Spring holder, 52c Spring, 60 Motor, 61 Cylindrical member, 62 Rotor, 63 Stator, 70 Cover member, 71 Through hole, 81 Rolling bearing, 82 Inner ring holding member, 83 Positioning member, 84 Positioning member, 85 Nut, 100, 200, 300, 400, 500 Spindle device, A rotation center axis.

Claims (10)

a cylindrical housing having an inner circumferential surface and an outer circumferential surface;
a shaft housed in the housing;
a rolling bearing rotatably supporting the shaft within the housing;
a non-rotating member attached to the inner peripheral surface;
a sensor attached to the non-rotating member and detecting the state of the rolling bearing;
a first wiring electrically connected to the sensor and drawn out from the non-rotating member;
and a hollow member;
The housing has a first end and a second end opposite the first end,
The non-rotating member is located closer to the second end than the rolling bearing,
A groove that is depressed toward the outer circumferential surface is formed in the inner circumferential surface,
The groove extends from the first end toward the second end,
the hollow member is inserted into the groove,
The hollow member has a third end attached to the non-rotating member and a fourth end opposite the third end,
In the bearing device, the first wiring is passed through the hollow member from the third end toward the fourth end. further comprising a lid member;
The rolling bearing has an outer ring attached to the inner peripheral surface,
The lid member is attached to the first end so as to be in contact with the outer ring from the first end side,
A through hole is formed in the lid member,
The bearing device according to claim 1, wherein the hollow member is inserted into the through hole. further comprising a connector electrically connected to the first wiring,
The bearing device according to claim 1 or 2, wherein the connector is attached to the fourth end. further comprising a lid member;
The rolling bearing has an outer ring attached to the inner peripheral surface,
The lid member is attached to the first end so as to be in contact with the outer ring from the first end side,
A through hole is formed in the lid member,
The bearing device according to claim 1, wherein the first wiring is passed through the through hole. a second wiring electrically connected to the sensor and drawn out from the non-rotating member;
further comprising a first communication unit and a second communication unit,
The first wiring is a signal wiring that transmits an output signal from the sensor,
The second wiring is a power wiring that supplies power to drive the sensor,
The first wiring and the second wiring are electrically connected to the first communication unit,
The first communication unit is configured to wirelessly transmit the output signal to the second communication unit,
The bearing device according to any one of claims 1 to 4, wherein the second communication unit is configured to wirelessly feed the power to the first communication unit. a third communication unit electrically connected to the first wiring;
antenna and
further comprising a generator that supplies electric power generated by the rotation of the shaft to the sensor and the third communication unit,
The first wiring is a signal wiring that transmits an output signal from the sensor,
The bearing device according to any one of claims 1 to 4, wherein the third communication unit is configured to wirelessly transmit the output signal. The bearing device according to any one of claims 1 to 6, wherein the non-rotating member is an outer ring spacer. The bearing device according to any one of claims 1 to 6, wherein the non-rotating member is a holding member that holds a spring that applies a constant preload to the rolling bearing. The bearing device according to any one of claims 1 to 8, wherein the sensor is a heat flux sensor that detects heat flux from the shaft side to the housing side. The bearing device according to any one of claims 1 to 9,
A spindle device, comprising: a motor that rotates the shaft.

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