JP5640635B2 - Bearing device, spindle device of machine tool, and machine tool - Google Patents

Description

  The present invention relates to a bearing device, a spindle device of a machine tool, and a machine tool, and more specifically, a bearing device capable of measuring an axial load acting on a rotating shaft such as a spindle shaft of a machine tool, a spindle device of a machine tool, and a machine tool. Related to machinery.

  In a machine tool, measuring an axial load acting on a spindle shaft has a great merit. That is, the axial load acting on the spindle axis of the machine tool is an important parameter having a great influence on machining accuracy, machining efficiency, tool life, and the like. Therefore, it is possible to select an appropriate machining condition by knowing the axial load. For example, machining conditions are generally determined by the rotation speed and feed rate of the tool, but are also affected by factors that are difficult to control, such as friction and heat generated by machining. Even if set to a constant value, the same machining accuracy is not always obtained. By considering the cutting load (that is, the axial load of the spindle shaft) corresponding to the change of the machining surface as a new parameter, it becomes possible to select a more strict machining condition and to improve the machining accuracy.

  Specifically, if the chip discharge amount is the same, the machining condition with a small cutting load is an efficient machining condition, which is advantageous for saving energy and extending the tool life. Further, from the increase in the cutting load, it is possible to estimate the deterioration of the cutting property (sharpness) of the tool and the occurrence of cutting edge wear and the like, and it becomes possible to know the tool life and the tool replacement time. Furthermore, by managing the history of changes in cutting load, it is possible to estimate bearing damage factors such as unreasonable cutting conditions and collisions (impact load) between the tool and workpiece, and from the grasped tool life characteristics The tool can be improved and improved.

  As described above, it is important to know the cutting load in a machine tool. However, in a machine tool of a type in which the tool rotates (tool rotating type machine tool), detecting a load acting on the tool and the rotating shaft is a type of machine tool in which the tool does not rotate (tool non-rotating type machine tool). Compared with difficulties.

  As a conventional device capable of detecting a load applied to a spindle of a machine tool, a load detection device for a machine tool spindle in which a bearing type sensor is disposed at a tip of the spindle is disclosed (for example, see Patent Document 1). ). The bearing type sensor described in Patent Document 1 has a rolling bearing disposed between a housing and a main shaft, and detects strain generated every time the rolling element of the bearing passes through the position of the strain gauge by a strain gauge attached to the outer periphery of the outer ring. Thus, the magnitude of the load applied to the main shaft is detected.

  There is also known a rolling bearing unit with a load measuring device in which a load applied between the outer ring and the hub is obtained by an encoder disposed on the hub of the bearing unit and a sensor close to and opposed to the detection surface of the encoder. (For example, refer to Patent Document 2).

JP-A-7-159260 JP 2006-317420 A

  However, the load detecting device for the spindle of the machine tool disclosed in Patent Document 1 is a device that indirectly detects the force acting on the inner ring of the bearing through the rolling elements and the outer ring of the bearing, such as generated heat accompanying rotation. As described above, there is a problem that it is difficult to remove disturbance (noise) that occurs irregularly and acts on the outer ring, and the load cannot be detected with high accuracy. In addition, since the sensor protrudes from the front side of the housing, there is a problem that not only the shaft length of the spindle becomes long but also a dedicated space for installing the sensor is required.

  In addition, the rolling bearing unit with a load measuring device described in Patent Document 2 has an encoder fixed to the hub of the bearing unit, and a sensor having a detection portion close to and opposed to the detection surface of the encoder is arranged on the outer ring to detect the rolling bearing unit. The load applied between the outer ring and the hub is obtained from the change in the output signal of the part, and the application to the spindle of the machine tool is also mentioned, but the specific configuration is not described.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a bearing device that can measure an axial load acting on a rotating shaft directly from a rotating member with high accuracy and a compact sensor. To provide a spindle device of a machine tool and a machine tool.

The above object of the present invention can be achieved by the following constitution.
(1) A stationary side race ring fitted and fixed to a stationary member, a rotation side race ring fitted and fixed to a rotating member, a stationary side race of the stationary side race ring, and a rotational side race of the rotary side race ring A bearing provided with a plurality of rolling elements which are arranged so as to be freely rollable between,
A rotation side spacer that is disposed on the side of the rotation side raceway and rotates together with the rotation side raceway;
An encoder in which the characteristics of the detected surface change alternately in the circumferential direction, and a sensor unit that is arranged opposite to the detected surface of the encoder and detects a change in the characteristics of the detected surface. A bearing device comprising:
The encoder is constituted by the rotating side spacer,
The detected surface of the encoder comprises a single row in the axial direction where the pitch of the characteristic that changes in the circumferential direction continuously changes in the axial direction ,
The sensor has a stepped cylindrical shape composed of a large diameter portion and a small diameter portion, and a detection portion is provided at the tip of the small diameter portion,
The stationary member has a sensor mounting hole including a large-diameter hole corresponding to the large-diameter portion and a small-diameter hole corresponding to the small-diameter portion, and a surface of the stationary member is provided with an edge of the large-diameter hole. A concave groove is formed,
In the sensor inserted into the sensor mounting hole, a step between the large diameter portion and the small diameter portion engages a step between the large diameter hole and the small diameter hole, and an upper surface of the large diameter portion is The stationary member is held by one end of a fixing jig fitted and fixed in the concave groove and positioned in the radial direction so that the detection portion at the tip of the small diameter portion faces the detection surface of the encoder. A bearing device that is fixed .
(2) The bearing includes a pair of bearings arranged to position an axial position of the rotating member,
The bearing device according to (1), wherein the rotation-side spacer constituting the encoder is disposed between the rotation-side races of the pair of bearings.
(3) A stationary side spacer is disposed between the stationary side track theory of the pair of bearings,
The bearing device according to (2), wherein the sensor extends from a through hole formed in the stationary side spacer and is opposed to the detected surface of the encoder.
(4) A stationary side race ring fitted and fixed to a stationary member, a rotational side race ring fitted and fixed to a rotating member, a stationary side race of the stationary side race ring, and a rotational side race of the rotary side race ring A bearing provided with a plurality of rolling elements which are arranged so as to be freely rollable between,
An encoder in which the characteristics of the detected surface change alternately in the circumferential direction, and a sensor unit that is arranged opposite to the detected surface of the encoder and detects a change in the characteristics of the detected surface. A bearing device comprising:
The detected surface of the encoder has a portion in which the pitch of the characteristic that changes in the circumferential direction continuously changes in the axial direction, and is configured in a single row in the axial direction.
The sensor has a stepped cylindrical shape composed of a large diameter portion and a small diameter portion, and a detection portion is provided at the tip of the small diameter portion,
The stationary member has a sensor mounting hole including a large-diameter hole corresponding to the large-diameter portion and a small-diameter hole corresponding to the small-diameter portion, and a surface of the stationary member is provided with an edge of the large-diameter hole. A concave groove is formed,
In the sensor inserted into the sensor mounting hole, a step between the large diameter portion and the small diameter portion engages a step between the large diameter hole and the small diameter hole, and an upper surface of the large diameter portion is The stationary side is held at one end of a fixing jig fitted and fixed in the concave groove and positioned in the radial direction, and the detection portion at the tip of the small diameter portion is disposed on the side of the stationary side race ring. A bearing device, wherein the bearing device extends from a through hole formed in a spacer and is fixed to the stationary member so as to face the detected surface of the encoder.
(5) A spindle device for a machine tool comprising the bearing device according to any one of (1) to (4) and capable of measuring an axial load of a spindle shaft that is the rotating member.
(6) A machine tool comprising the spindle device according to (5) .

  According to the bearing device of the present invention, it comprises a sensor unit comprising an encoder in which the characteristics of the surface to be detected alternately change in the circumferential direction, and a sensor that is arranged opposite to the surface to be detected and detects a change in the characteristics, Since the encoder is constituted by the rotary spacer, the sensor unit can be arranged in an existing space without providing a new dedicated space, and the sensor-equipped bearing device can be reduced in size.

In addition, since the detected surface of the encoder has a single row in the axial direction where the pitch of the characteristic that changes in the circumferential direction continuously changes in the axial direction, the sensor is configured by only one magnetic sensor. Can be configured. As a result, the cost of the sensor unit can be reduced, and the axial widths of the sensor and encoder can be reduced.
Further, the sensor has a stepped cylindrical shape composed of a large diameter portion and a small diameter portion, a detection portion is provided at the tip of the small diameter portion, and the stationary member is provided with a large diameter hole corresponding to the large diameter portion and a small diameter portion. A sensor mounting hole having a corresponding small diameter hole is provided, and a concave groove reaching the edge of the large diameter hole is formed on the surface of the stationary member, and the sensor inserted into the sensor mounting hole has a large diameter portion and a small diameter portion. The step between the two is engaged with the step between the large-diameter hole and the small-diameter hole, and the upper surface of the large-diameter portion is held by one end of the fixing jig fitted and fixed in the concave groove to be positioned in the radial direction. And since the detection part of the front-end | tip of a small diameter part is fixed to a stationary member so as to oppose the to-be-detected surface of an encoder, the gap of a sensor and an encoder can be set with a sufficient precision. Further, the positioning around the central axis of the sensor can be set accurately.

  Further, since the rotation side spacer constituting the encoder is arranged between the rotation side races of the pair of bearings for positioning the axial position of the rotation member, the influence of expansion and contraction of the rotation member is suppressed, and the accuracy is high. Load measurement is possible.

  Furthermore, since the sensor extends from the through hole formed in the stationary spacer of the pair of bearings and is opposed to the detection surface of the encoder, the sensor unit is arranged without providing a new dedicated space. Therefore, the sensor-equipped bearing device can be reduced in size.

According to another bearing device of the present invention, a sensor comprising: an encoder in which the characteristics of the detected surface are alternately changed in the circumferential direction; and a sensor that is disposed opposite to the detected surface and detects the change in the characteristics. The sensor has a stepped cylindrical shape consisting of a large diameter portion and a small diameter portion, a detection portion is provided at the tip of the small diameter portion, and the stationary member has a large diameter hole corresponding to the large diameter portion and a small diameter A sensor mounting hole having a small-diameter hole corresponding to the portion, a concave groove reaching the edge of the large-diameter hole is formed on the surface of the stationary member, and the sensor inserted into the sensor mounting hole has a large-diameter portion and The step portion between the small diameter portions engages with the step between the large diameter hole and the small diameter hole, and the upper surface of the large diameter portion is held by one end of the fixing jig fitted and fixed in the concave groove, and the radius It is positioned in a direction, detection of the tip of the small diameter portion, extending from the through hole formed in the stationary spacer, encoder Because it is fixed to the stationary member so as to opposed to the detected surface, disposed with a gap between the sensor and the encoder can be precisely set, the sensor unit to the existing space without providing a new dedicated space Thus, the sensor-equipped bearing device can be reduced in size . Further, the positioning around the central axis of the sensor can be set accurately.

  In addition, since the spindle device of a machine tool and the machine tool are provided with the bearing device described above, it is possible to measure the axial load acting on the spindle shaft at the time of cutting, and considering this axial load as a new parameter of the machining conditions, Stricter machining conditions can be selected, and machining accuracy can be improved. Furthermore, it is possible to estimate the tool life, the tool replacement time, and the bearing damage factor, and to improve and improve the tool.

It is sectional drawing of the main axis | shaft apparatus of 1st Embodiment which concerns on this invention. It is principal part sectional drawing of the main axis | shaft apparatus shown in FIG. It is a perspective view of the encoder shown in FIG. It is IV-IV sectional drawing shown in FIG. (A) is a perspective view of the sensor shown in FIG. 1, (b) is its plan view, and (c) is its side view. It is a perspective view of the sensor attachment hole provided in the housing shown in FIG. (A) is a top view of the sensor attachment hole shown in FIG. 6, (b) is the sectional drawing. It is explanatory drawing which shows the assembly | attachment procedure of the sensor shown in FIG. (A) shows the position of the detection part with respect to an encoder, (b)-(d) is a diagram which shows the output signal of the sensor which changes with the fluctuation | variation of the axial load of the spindle apparatus shown in FIG. It is sectional drawing of the main axis | shaft apparatus of the modification of 1st Embodiment. It is a perspective view of the encoder of 2nd Embodiment. (A) shows the position of the detection part with respect to the encoder shown in FIG. 11, and (b) to (d) are diagrams showing the output signal of the sensor that changes in accordance with fluctuations in the axial load of the spindle device. It is a perspective view of the encoder of the modification of 2nd Embodiment. (A) shows the position of the detection part with respect to the encoder shown in FIG. 13, and (b) to (d) are diagrams showing the output signal of the sensor that changes with fluctuations in the axial load of the spindle device. It is principal part sectional drawing of the main shaft apparatus of 3rd Embodiment. It is a perspective view of the encoder of 3rd Embodiment. It is the expanded view which looked at the encoder of 3rd Embodiment from the outer peripheral side. It is a perspective view of the encoder which concerns on the modification of 3rd Embodiment. It is a perspective view of the encoder which concerns on the other modification of 3rd Embodiment. It is a perspective view of the sensor attachment hole of 4th Embodiment. It is a top view of the sensor attachment hole shown in FIG. It is principal part sectional drawing of the main shaft apparatus of 5th Embodiment. It is principal part sectional drawing of the main shaft apparatus of 6th Embodiment. It is principal part sectional drawing of the main shaft apparatus of 7th Embodiment. It is principal part sectional drawing of the spindle apparatus of 8th Embodiment. It is principal part sectional drawing of the main shaft apparatus of 9th Embodiment. It is principal part sectional drawing of the main axis | shaft apparatus of the modification of 9th Embodiment. It is principal part sectional drawing of the main axis | shaft apparatus of 10th Embodiment. It is principal part sectional drawing of the main axis | shaft apparatus which is not provided with a cooling mechanism. It is principal part sectional drawing of the other spindle apparatus which is not provided with a cooling mechanism. It is principal part sectional drawing of a main axis | shaft apparatus provided with a wireless sensor. It is principal part sectional drawing of a main axis | shaft apparatus provided with the sensor unit with which the encoder was provided in the inner ring spacer for positioning. It is principal part sectional drawing of a main axis | shaft apparatus provided with the sensor unit with which the encoder was provided in the inner ring. 1 is a schematic view of a portal machining center to which a spindle device of the present embodiment is applied.

  Hereinafter, each embodiment of a spindle device according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIGS. 1 and 2, the spindle device 10 of the machine tool according to the first embodiment is a motor built-in system, and a hollow rotating shaft (spindle shaft) 11 as a rotating member is provided at the center thereof. Is provided. A tool (not shown) is held at the axial end of the rotating shaft 11 (left side in FIG. 1).

  The rotary shaft 11 is rotatably supported by a housing 50 that is a stationary member by a pair of front bearings 20 and 30 that support the tool side and a rear bearing 40 that supports the opposite tool side. A rotor 51 is fitted on the outer peripheral surface of the rotary shaft 11 between the front bearings 20 and 30 and the rear bearing 40. In addition, the stator 52 disposed around the rotor 51 is fixed to the housing 50, and by supplying electric power to the stator 52, a rotational force is generated in the rotor 51 to rotate the rotating shaft 11. The housing 50 includes a housing 50 a and a housing 50 b that are divided in the axial direction between the front bearing 30 and the stator 52.

  The front bearings 20 and 30 are a pair of angular ball bearings having substantially the same dimensions arranged so as to form a rear combination, outer rings 21 and 31 that are stationary bearing rings, and inner rings 22 and 32 that are rotating bearing rings. And a plurality of balls 23 and 33 as rolling elements arranged with a contact angle between the outer ring raceway groove which is a stationary side raceway and the inner ring raceway groove which is a rotation side raceway.

  The outer rings 21 and 31 of the front bearings 20 and 30 are fitted in the housing 50 and fixed to the housing 50 via an outer ring spacer 54 which is a stationary side spacer by a front bearing outer ring presser 53 which is bolted to the housing 50. ing.

  Further, the inner rings 22 and 32 of the front bearings 20 and 30 are externally fitted to the rotating shaft 11 and are fixed to the rotating shaft 11 via an inner ring spacer 81 which is a rotating side spacer by a nut 55 fastened to the rotating shaft 11. Has been. The front bearings 20 and 30 are loaded with a fixed position preload by a nut 55, and the axial position of the rotary shaft 11 is positioned by the front bearings 20 and 30.

  As shown in FIG. 3, the encoder 84 has a plurality of detection combination portions 85, 85 arranged at equal intervals in the circumferential direction on the outer peripheral surface of an inner ring spacer 81 made of a magnetic metal material. Each of these combination parts 85 and 85 to be detected is constituted by a pair of individualized parts 86 and 86 each having different characteristics from the other parts. In the case of the present embodiment, such individualized portions 86 and 86 have long grooves.

  The interval in the circumferential direction between each pair of individualized portions 86 and 86 constituting each detected combination portion 85 and 85 is continuous in the same direction with respect to the axial direction in all the detected combination portions 85 and 85. Change. That is, the interval in the circumferential direction between the pair of individualized portions 86, 86 constituting each detected combination portion 85, 85 becomes smaller in the axial direction one end (upper right end in FIG. 3) of the encoder 84, The interval in the circumferential direction between the individualized portions 86 and 86 constituting each of the detected combination portions 85 and 85 adjacent to each other in the circumferential direction becomes smaller toward the other axial end of the encoder 84 (the lower left end in FIG. 3). Inclined in the direction. The encoder 84 constitutes a sensor unit 80 together with a sensor 82 described later.

  Returning to FIG. 1, the rear bearing 40 is a cylindrical roller bearing, and includes an outer ring 41, an inner ring 42, and a plurality of cylindrical rollers 43 as rolling elements. The outer ring 41 of the rear bearing 40 is fitted in the housing 50 and fixed to the housing 50 via the outer ring spacer 44 by a rear bearing outer ring retainer 56 that is bolted to the housing 50. The inner ring 42 of the rear bearing 40 is fixed to the rotating shaft 11 via an inner ring spacer 45 by another nut 57 fastened to the rotating shaft 11.

  On the outer peripheral surface of the housing 50 corresponding to the front bearings 20 and 30 and the stator 52 in the axial direction, annular cooling oil grooves 58 and 59 are formed. The cooling oil grooves 58, 59 are covered with ring-shaped cooling jackets 60, 61 fitted with O-rings 62, 63 and fitted to the housing 50. The front bearings 20 and 30 and the stator 52 are cooled by the cooling oil supplied to the cooling oil grooves 58 and 59.

  As shown in FIG. 4, an oil supply nozzle 67 is disposed in each of a pair of nozzle holes 66 and 54 b provided through the housing 50 and the outer ring spacer 54 in the radial direction. Then, the lubricating oil supplied from the lubricating device is discharged from the nozzle (not shown) of the oil supply nozzle 67 toward the front bearings 20 and 30 to lubricate the front bearings 20 and 30. The lubrication method may be any of grease lubrication, oil-air lubrication, oil mist lubrication, direct injection lubrication, and the like.

  A sensor mounting hole 68 and a through hole 54a are formed in the housing 50 and the outer ring spacer 54 continuously in the radial direction, respectively. The sensor mounting holes 68 are provided at substantially the same position as the oil supply nozzle 67 (nozzle hole 66) in the axial direction and at different positions in the circumferential direction. A sensor 82 constituting the sensor unit 80 is disposed in the sensor mounting hole 68.

  By disposing the sensor mounting hole 68 at substantially the same position in the axial direction as the oil supply nozzle 67 (nozzle holes 66, 54b), a dedicated space for disposing the sensor 82 becomes unnecessary, and the size can be reduced. The circumferential direction phase of the oil supply nozzle 67 (nozzle holes 66, 54b) and the sensor 82 (sensor mounting hole 68) is not particularly limited and can be set arbitrarily.

  As shown in FIG. 5, the sensor 82 has a built-in magnetic sensor 90 as a detection unit, and is formed in a stepped cylindrical shape including a large diameter portion 82 a and a small diameter portion 82 b. The large-diameter portion 82a and the small-diameter portion 82b are provided with O-ring grooves 87a and 87b, respectively, and a U-shaped groove 82c is formed on the upper surface of the large-diameter portion 82a. One end of an elliptical fixing jig 88 is fitted into the U-shaped groove 82c.

  As shown in FIGS. 6 and 7, the sensor mounting hole 68 provided in the housing 50 is a stepped hole having a large diameter portion 68a and a small diameter portion 68b, and is a first hole for routing the wiring 83 of the sensor 82. One routing hole 70 communicates with the small diameter portion 68b and is provided in the axial direction. Furthermore, an ellipse 68c whose longitudinal direction is directed to the first routing hole 70 is provided in communication with the first routing hole 70 at the stepped portion of the large diameter portion 68a and the small diameter portion 68b.

  Further, a U-shaped groove 68d having one end continuous to the large diameter portion 68a is formed on the outer peripheral surface of the cooling oil groove 58. A female screw 69 for fixing the sensor 82 is provided in the U-shaped groove 68d in the radial direction. If the outer shapes of the sensor 82 and the oil supply nozzle 67 are set to the same shape, the nozzle hole 66 and the sensor mounting hole 68 (the large diameter portion 68a and the small diameter portion 68b) can be processed in the same processing step. Can contribute to cost reduction.

  Referring to FIG. 1, the first wiring hole 70 is machined from the side opposite to the tool of the housing 50 a, and the inclined hole 71 provided in the radial direction and inclined from the outer peripheral surface of the housing 50, and the first wiring It communicates with a second routing hole 72 that extends parallel to the search hole 70 to the side opposite to the tool. In this way, the first wiring hole 70, the inclined hole 71, and the second wiring hole 72 are bent, so that the wiring 83 of the sensor 82 can be routed without interfering with the stator 52. A plug 74 is inserted and closed at the end of the first wiring hole 70 on the side opposite to the tool, and foreign matter intrusion from the motor side is prevented.

  As shown in FIGS. 1 and 8, the sensor 82 has O-rings 91a and 91b mounted in O-ring grooves 87a and 87b, and the wiring 83 of the sensor 82 is connected to the first routing hole 70, the inclined hole 71 and the second It is assembled by being inserted into the routing hole 72 and inserted into the sensor mounting hole 68 of the housing 50 and the through hole 54a of the outer ring spacer 54.

  At this time, since the sensor mounting hole 68 is provided with an oval 68c communicating with the first wiring hole 70, the wiring 83 is not sandwiched between the sensor mounting hole 68 and the sensor 82 and is damaged. Absent. Further, the O-rings 91a and 91b attached to the sensor 82 prevent the lubricant from entering the cooling oil groove 58 and the first bearing hole 70 from the front bearings 20 and 30 side.

  In addition, the insertion work of the wiring 83 with respect to the 1st routing hole 70, the inclination hole 71, and the 2nd routing hole 72 is the 1st routing hole 70, when it is difficult to insert at once as mentioned above. In addition, the wiring 83 inserted through the inclined hole 71 may once be taken out of the inclined hole 71 and then inserted through the inclined hole 71 into the second routing hole 72 again. In addition, after the wiring 83 is inserted, a plug (not shown) is inserted into the opening of the inclined hole 71 and closed, thereby preventing foreign matter from entering. One end of the wiring 83 wired in this way is connected to the arithmetic unit 150 and an output signal detected by the sensor 82 is input.

  Then, the fixing jig 88 is fitted into the U-shaped groove 82 c of the sensor 82 and the U-shaped groove 68 d of the housing 50, and the male screw 89 is screwed to the female screw 69 of the housing 50 and fixed. As a result, the magnetic sensor 90 provided at the tip of the sensor 82 is positioned at a predetermined position and is disposed so as to face the detected surface of the encoder 84 formed on the outer peripheral surface of the inner ring spacer 81.

  The relative position between the sensor 82 and the detected surface of the encoder 84 is such that the magnetic sensor 90 is located in the middle in the axial direction of the detected surface. Specifically, the position of the magnetic sensor 90 is an axial intermediate portion (imaginary line) of the encoder 84 that is an intermediate intermediate position of the inner ring spacer 81 disposed between the front bearings 20 and 30 to which the fixed position preload is applied. It is set to coincide with α).

  The operation of the sensor unit 80 of the spindle device 10 of the first embodiment will be described with reference to FIG. The output signal of the sensor 82 having the detection portion opposed to the outer peripheral surface that is the detection surface of the encoder 84 changes at the moment of facing the individualized portions 86 and 86. The changing interval (cycle) changes with the change in the axial position of the portion of the sensor 82 where the detection unit faces. For example, when an axial load is not applied to the rotating shaft 11 (inner ring spacer 81), the detection unit of the sensor 82 scans the center of the detected surface indicated by the phantom line α, and the output signal is It changes as shown in 9 (c).

  Here, when an axial load is applied to the rotary shaft 11, that is, the inner ring spacer 81 in the direction from the tool side to the counter tool side in FIG. 9A, the position of the detection unit with respect to the encoder 84 is shown in FIG. 9A. It moves on the virtual line β, and the output signal changes as shown in FIG.

  Further, when an axial load is applied to the rotary shaft 11 in the direction from the non-tool side to the tool side, the positions of the pair of detection units move on the virtual line γ shown in FIG. 9A, and the output signal is as shown in FIG. It changes as shown in d).

  The structure of the magnetic sensor 90 is not particularly limited as long as a permanent magnet is incorporated. That is, even a so-called passive type in which a coil is wound around a pole piece that guides the flow of magnetic flux from the permanent magnet is incorporated with a magnetic detection element that changes its characteristics in accordance with the magnetic flux density. The so-called active type is also used. Further, the sensor 82 of the present embodiment may be any sensor that can detect the edge of the individualized portion 86 that is a long groove, and an optical sensor or the like may be used.

  As described above, the output signal of the magnetic sensor 90 changes in proportion to the direction of the axial load acting on the rotating shaft 11 and in proportion to the magnitude of the axial load. Therefore, if the rigidity (spring constant) of the front bearings 20 and 30 loaded with the fixed position preload is measured or calculated in advance, the relationship between the magnitude of the axial load and the amount of displacement of the rotary shaft 11 is obtained. Based on the pattern of the output signal from the sensor 90, the direction and magnitude of the axial load that acts on the rotating shaft 11 is obtained by the arithmetic device 150.

  Further, since the inner ring spacer 81 constituting the encoder 84 is disposed between the front bearings 20 and 30 which are a pair of angular ball bearings arranged in a rear combination, the intermediate position in the axial direction of the inner ring spacer 81 rotates. Since the shaft 11 becomes the center in the axial direction when it expands and contracts due to heat, the influence of expansion and contraction of the rotating shaft 11 is suppressed, and accurate load measurement becomes possible.

  Furthermore, since the wiring 83 passes through the inside of the housing 50 through the first wiring hole 70, the inclined hole 71, and the second wiring hole 72, it is possible to remove chips and chips during processing without providing a separate wiring cover. The cord can be protected from cutting oil and the like, and space saving is achieved. In particular, in the swivel type spindle device, if the wiring is led out from the inside of the housing 50 to the inside of the turning arm that supports the spindle device 10, the wiring can be routed without exposing it to the outside.

  In the present embodiment, the detected surface of the encoder 84 is configured by a single row in the axial direction where the pitch of the characteristic that changes in the circumferential direction continuously changes in the axial direction. Only one magnetic sensor 90 can be used. As a result, the cost of the sensor unit can be reduced, and the axial width of the inner ring spacer 81 constituting the sensor 82 and the encoder 84 can also be reduced. Thereby, the axial direction length of the spindle device 10 can also be shortened. In particular, in the case of a machine tool in which the spindle axis turns on a 5-axis machine or the like (for example, turning around ± 120 °), the turning radius can be reduced if the spindle axis length is shortened. Thus, there is an advantage that the operation of the spindle device 10 is facilitated and the machining program can be easily created and the workability can be improved.

  FIG. 10 is a cross-sectional view of the main part of a spindle device according to a modification of the first embodiment of the present invention. In the spindle device 10, the first wiring hole 70 formed in the housing 50 is machined from the tool side and communicates with the inclined hole 71. As a result, the first wiring hole 70 can be closed by the front bearing outer ring presser 53, and there is no need to provide the plug 74. Further, the housing 50 can be easily processed even if the housing 50 is not divided into two in the axial direction.

(Second Embodiment)
FIG. 11 is a perspective view of an encoder according to the second embodiment of the present invention. In the encoder 84 of the second embodiment, a convex portion 93 as a first detected portion and a concave portion 94 as a second detected portion having different characteristics are provided on the outer peripheral surface of the inner ring spacer 81 made of a magnetic metal material. They are formed alternately and at equal intervals in the circumferential direction. The convex portion 93 and the concave portion 94 are formed in a trapezoidal shape or an inverted trapezoidal shape. The width of the convex portion 93 is wider toward one end in the axial direction (lower end in FIG. 11), and the width of the concave portion 94 is the other end in the axial direction (see FIG. 11 is wider on the side.

  In the spindle device including the encoder 84 of the present embodiment, the magnetic sensor 90 of the sensor 82 is positioned on the virtual line α shown in FIG. 12A in a state where an axial load is not applied to the rotating shaft 11. . Accordingly, the output signal (duty ratio) of the magnetic sensor 90 changes as shown in FIG.

  Here, when an axial load is applied to the rotary shaft 11 in the direction from the tool side to the non-tool side in FIG. 12A due to the workpiece processing, the axial position of the inner ring spacer 81, that is, the encoder 84 is moved together with the rotary shaft 11. It changes to the non-tool side. As a result, the position of the magnetic sensor 90 relative to the encoder 84 moves on the virtual line β shown in FIG. 12A, and the output signal (duty ratio) of the magnetic sensor 90 changes as shown in FIG. To do.

Further, when an axial load is applied to the rotary shaft 11 in the direction from the opposite tool side to the tool side in FIG. 12A, the axial position of the inner ring spacer 81, that is, the encoder 84 changes along with the rotary shaft 11 to the tool side. Thus, the position of the magnetic sensor 90 relative to the encoder 84 moves on the virtual line γ shown in FIG. 12A, and the output signal (duty ratio) of the magnetic sensor 90 changes as shown in FIG. . Therefore, based on the output signal (duty ratio) from the detection unit, the direction and the magnitude of the axial load acting on the rotating shaft 11 are obtained by the arithmetic device 150.
Other configurations and operations are the same as those in the first embodiment.
Further, in the present embodiment, the encoder 84 is composed of a permanent magnet, and the first detected part magnetized in the S pole and the second detected part magnetized in the N pole are alternately arranged in the circumferential direction. It is good.

  FIG. 13 is a perspective view of an encoder according to a modification of the second embodiment of the present invention. The encoder 84 stabilizes the output signal of the sensor 90 by devising the shapes of the convex portions 93 and 93 and the concave portions 94 and 94 formed on the outer peripheral surface thereof. That is, in the case of the present embodiment, the axial end portions of the convex portions 93 and 93 and the concave portions 94 and 94 are parallel to each other so that the width dimension in the circumferential direction of the encoder 84 does not change in the axial direction of the encoder 84. The parts 93a, 93b, 94a, 94b are used. Therefore, the pitch at which the characteristic of the outer peripheral surface that is the detection surface of the encoder 84 changes in the circumferential direction varies depending on the axial position at the axial intermediate portion of the outer peripheral surface, but at the axial position at both axial end portions. Regardless of

  In the case of this modification, the reason why the output signal of the sensor 82 can be stabilized by providing the parallel portions 93a, 93b, 94a, 94b is as follows. As described above, by using an encoder made of a magnetic material and having a concavo-convex portion on the surface to be detected, the pitch of the characteristic change of the surface to be detected can be made higher than that of an encoder made of a permanent magnet. However, in the case of the above-described embodiment, if the interval between the concave portion and the convex portion is shortened in order to shorten the pitch of the characteristic change, the sensor detection unit is arranged at both end portions in the width direction (axial direction) of the detected surface of the encoder. In a state of being opposed to the vicinity of both ends, the flow of magnetic flux flowing between the detection unit and the detection surface becomes unstable, and the output of the sensor tends to become unstable. For example, when the pitch between the convex portions 93 and 93 and the concave portions 94 and 94 is shortened with the encoder 84 shown in FIG. 11, the bases of the trapezoidal convex portions 93 and 93 adjacent in the circumferential direction are close to each other. In particular, in order to enable detection of the rotational speed of the rotary shaft 11 even when the encoder 84 and the sensor 82 are greatly displaced in the axial direction, the relative displacement amount in the axial direction allowed between the encoder 84 and the sensor 82 is set. In order to ensure, when the height of the trapezoidal shape is increased, the tendency of the bases of the trapezoidal convex portions 93 and 93 adjacent in the circumferential direction to approach each other becomes remarkable as described above.

  On the other hand, in the case of this modification, the bases of the trapezoidal convex portions 93 and 93 adjacent to each other in the circumferential direction are excessively close to each other with the provision of the parallel portions 93a, 93b, 94a, and 94b. You can prevent things. Even when the detection portion of the sensor 82 faces the portion corresponding to the bottom sides of the convex portions 93 and 93 at the axial end portion of the outer peripheral surface of the encoder 84, the detection portion of the sensor 82 and the detected surface of the encoder 84 The output of the sensor 82 can be stabilized by stabilizing the flow of magnetic flux flowing between them. Further, even if the axial displacement amount between the encoder 84 and the sensor 82 is slightly increased, the rotational speed of the rotating shaft 11 can be detected by the sensor 82.

In addition, although the shape of the circumferential direction both-sides edge of each parallel part 93a, 93b, 94a, 94b is made into the straight line, the shape of this part does not necessarily need to be a straight line. For example, depending on the sensitivity of the sensor 82 and the sensitive range (spot diameter), the sensor 82 may be slightly inclined with respect to the axial direction or may be formed in an arc shape having a large curvature radius.
The structure of the sensor 82 combined with the encoder 84 is not particularly limited as long as it has a permanent magnet incorporated therein. That is, even a so-called passive type in which a coil is wound around a pole piece that guides the flow of magnetic flux from the permanent magnet is incorporated with a magnetic detection element that changes its characteristics in accordance with the magnetic flux density. The so-called active type can also be used. However, as shown in FIG. 14, the convex portions 93 and 93 and the concave portions 94 and 94 existing on the outer peripheral surface of the encoder 84 with the detection portion of the sensor 82 facing the intermediate portion in the axial direction of the encoder 84. In order to sense the ratio of the length dimension with respect to the rotation direction, a smaller spot diameter of the sensor 82 is preferable from the viewpoint of obtaining this ratio with high accuracy.

(Third embodiment)
FIG. 15 is a cross-sectional view of the main part of the spindle device according to the third embodiment of the present invention. The inner ring spacer 81 of the third embodiment has axial widths La and Lb and depths Ha and Hb at both axial ends of the outer peripheral surface of the inner ring spacer 81 (FIG. 3) of the first embodiment. The groove portions 81a and 81b are recessed.

  Specifically, as shown in FIGS. 16 and 17, in the inner ring spacer 81 of this embodiment, the axial widths La and Lb of the grooves 81 a and 81 b are set to 1 mm or more, respectively, and the individualization of the encoder 84 is achieved. The portion 86 is continuously formed so as to open to both axial end faces 81aS and 81bS of the groove portions 81a and 81b. Further, the depths Ha and Hb of the groove portions 81a and 81b are set to be larger than the depth h of the individualized portion 86, and the outer peripheral surface of the groove portions 81a and 81b is closer to the inner diameter side than the outer peripheral surface of the individualized portion 86. positioned.

  According to this inner ring spacer 81, when providing the individualized portion 86 of the encoder 84, the groove portions 81a and 81b cut out to the inner diameter side of the individualized portion 86 are formed at both ends in the axial direction. The individualized portion 86 can be cut through in the axial direction.

  Therefore, when the individualized portion 86 of the encoder 84 is cut into the inner ring spacer 81 having the groove portions 81a and 81b by a milling machine or the like, the individualized portion 86 can be formed by cutting it in the axial direction. , Workability can be improved. Further, when the processing machine passes through the axial end faces 81aS and 81bS of the grooves 81a and 81b, even if burrs are generated in the vicinity of the axial end faces 81aS and 81bS, the inner ring where the burrs contact the inner rings 22 and 32. Since the axial end surfaces 81c and 81d of the spacer 81 are not affected, the parallelism of the end surface of the inner ring spacer 81 is improved. As a result, the inner rings 22, 32 and the inner ring spacer 81 can be assembled with high accuracy.

Further, since the individualized portion 86 is formed by cutting between the axial end faces 81aS and 81bS of the groove portions 81a and 81b in the axial direction, the dimensional error in the axial direction of each individualized portion 86 can be reduced. Can do. As a result, it is possible to suppress the vibration of the spindle device due to the unbalanced dimensions of the individualized portions 86. This is particularly effective when the tool is rotated at a high speed.
Other configurations and operations are the same as those in the first embodiment.

  In addition, the configuration of the inner ring spacer 81 having the groove portions 81a and 81b of the present embodiment is similar to that of the inner ring spacer 81 that constitutes the encoder 84 by the convex portion 93 and the concave portion 94 of the second embodiment, as shown in FIG. As shown in FIG. 19, as shown in FIG. 19, between the inner rings constituting the encoder 84 by the convex portion 93 and the concave portion 94 having the parallel portions 93 a, 93 b, 94 a, and 94 b, which are modifications of the second embodiment. The seat 81 can also be applied.

(Fourth embodiment)
20 is a perspective view of a sensor mounting hole according to the fourth embodiment of the present invention, and FIG. 21 is a plan view of the sensor mounting hole. Similarly to the sensor mounting hole 68 of the first embodiment, the sensor mounting hole 68 of the fourth embodiment has a large diameter portion 68a through which the large diameter portion 82a (see FIG. 5) of the sensor 82 is inserted and a small diameter of the sensor 82. This is a three-stage stepped hole having a small diameter portion 68b through which the portion 82b is inserted and further having an intermediate diameter portion 68e formed between the large diameter portion 68a and the small diameter portion 68b. A first routing hole 70 for routing the wiring 83 of the sensor 82 communicates with the middle diameter portion 68e and is provided in the axial direction. Also, the housing 50 is provided with a U-shaped groove 68d for fixing the sensor and a female screw 69, as in the first embodiment.

The middle diameter portion 68e of the sensor mounting hole 68 is for preventing the interference between the wiring 83 and the sensor mounting hole 68 when the sensor 82 is inserted into the sensor mounting hole 68 and facilitating assembly. It is desirable that the wiring 83 is as small as possible as long as interference of the wiring 83 can be prevented.
Other configurations and operations are the same as those in the first embodiment.

(Fifth embodiment)
FIG. 22 is a cross-sectional view of the main part of the spindle device according to the fifth embodiment of the present invention. In the spindle device 10 of the fifth embodiment, a ring groove 95 concentrically with the sensor mounting hole 68 is formed in an annular cooling oil groove 58. A cylindrical lid body 97 fitted with an O-ring 96 is fitted in the ring groove 95. According to the spindle device 10, the cooling oil groove 58 and the sensor 82 are separated by the lid body 97 and sealed by the O-ring 96, so that the cooling oil is prevented from adhering to the sensor 82. Further, it is not necessary to process the O-ring groove 87a in the large diameter portion 82a of the sensor 82. Other configurations and operations are the same as those in the first embodiment.

(Sixth embodiment)
FIG. 23 is a cross-sectional view of the main part of the spindle device according to the sixth embodiment of the present invention. In the spindle device 10 of the sixth embodiment, in order to route the wiring 83 of the sensor 82, the routing hole 98 communicating from the tool side to the sensor mounting hole 68 (small diameter portion 68b) is processed. Further, a wiring groove 99 is provided in the front bearing outer ring presser 53, and a wiring cover 100 extending in the axial direction is fixed to the outer peripheral surface of the housing 50 so as to straddle the circumferential position where the wiring groove 99 opens. . Thereby, the wiring 83 led out from the wiring hole 98 toward the tool side passes through the wiring groove 99 of the front bearing outer ring retainer 53 and is covered and wired by the wiring cover 100.

According to the spindle device 10, when the distance from the sensor mounting hole 68 to the end portion (left end portion in the figure) of the housing 50 is short, the amount of processing of the housing 50 is reduced, which is advantageous in processing. In addition, since the wiring 83 of the sensor 82 is covered with the front bearing outer ring presser 53 and the wiring cover 100, it is possible to prevent damage or cutting to the wiring 83 due to chips or the like during processing.
In addition, about another structure and effect | action, it is the same as that of the main axis | shaft apparatus 10 of 1st Embodiment. Further, depending on the external environment of the housing 50, the wiring 83 may be routed without providing the wiring cover 100.

(Seventh embodiment)
FIG. 24 is a cross-sectional view of the main part of the spindle device according to the seventh embodiment of the present invention. In the spindle device 10 of the seventh embodiment, the routing groove 99 formed in the front bearing outer ring presser 53 extends in the radial direction without opening to the outer peripheral surface of the housing 50, and the routing groove 99 is provided in the cooling jacket 60. A wiring hole 101 that communicates with is formed. The wiring 83 led out from the routing hole 98 toward the tool side is routed through the routing groove 99 of the front bearing outer ring retainer 53 and the routing hole 101 of the cooling jacket 60. Thus, as in the first embodiment, the cord can be protected from chips and cutting oil during processing without providing a separate wiring cover, and space saving can be achieved.
Other configurations and operations are the same as those in the sixth embodiment.

(Eighth embodiment)
FIG. 25 is a cross-sectional view of the main part of the spindle device according to the eighth embodiment of the present invention. In the spindle device 10 of the eighth embodiment, the sensor hole 102 for attaching the sensor 82 to the cooling jacket 60 is formed concentrically with the sensor attachment hole 68 of the housing 50. In the sensor 82, the large-diameter portion 82a has a long length, and the wiring 83 is led out from the upper surface of the large-diameter portion 82a. O-rings 91a and 91c are attached to the large diameter portion 82a at positions corresponding to the sensor mounting hole 68 and the sensor hole 102, respectively.

  The sensor 82 is inserted into the sensor hole 102 of the cooling jacket 60, the sensor mounting hole 68 of the housing 50, and the through hole 54 a of the outer ring spacer 54, and is fixed to the cooling jacket 60 by a fixing jig 88 and a male screw 89. The sensor 82, the sensor mounting hole 68, and the sensor hole 102 are sealed with O-rings 91a and 91c, respectively. Further, the wiring 83 led out from the sensor 82 in the radial direction is covered and wired by the wiring cover 100.

According to the spindle device 10, it is not necessary to provide a wiring hole that is difficult to be processed in the housing 50 by simply forming the sensor hole 102 in the cooling jacket 60, which is advantageous in processing.
Other configurations and operations are the same as those in the sixth embodiment.

(Ninth embodiment)
FIG. 26 is a cross-sectional view of the main part of the spindle device according to the ninth embodiment of the present invention. The sensor 103 incorporated in the spindle device 10 of the ninth embodiment is a connector connection type sensor 103 provided with a female connector 104 on the side surface of the small diameter portion 82b, unlike the wire direct attachment type sensor 82. A male connector 105 that can be fitted to the female connector 104 is provided at the tip of the wiring 83.

In the sensor 103 of this embodiment, the wiring 83 is inserted into the first wiring hole 70 with the cooling jacket 60 removed, and the male of the wiring 83 extending from the sensor mounting hole 68 outside the housing 50. After the connector 105 is connected to the female connector 104 of the sensor 103, the sensor 103 is inserted into the sensor mounting hole 68 while pushing the wiring 83 into the first wiring hole 70, and is fixed by fixing with the fixing jig 88 and the male screw 89. It is done.
Other configurations and operations are the same as those in the first embodiment.

  FIG. 27 is a cross-sectional view of main parts of a main spindle device according to a modification of the ninth embodiment according to the present invention. The sensor 103 incorporated in the spindle device 10 of the present modification is a connector connection type sensor 103 shown in FIG. 26, and the housing 50 has a wiring hole 98 machined from the tool side.

  The sensor 103 is inserted and fixed in the sensor mounting hole 68 of the housing 50 and the through hole 54a of the outer ring spacer 54 with the female connector 104 facing the tool side (routing hole 98 side). As a result, the female connector 104 is positioned facing the wiring hole 98. Here, the male connector 105 of the wiring 83 is placed on the connection jig 110 and inserted in the direction of the arrow from the tool side of the routing hole 98 to connect the male connector 105 and the female connector 104. Here, the distal end portion 110a of the connecting jig 110 is positioned so that the male connector 105 does not rotate and does not move rearward in the axial direction, and can be reliably connected to the female connector 104. In addition, the connection jig 110 can be removed after the connection. The wiring 83 led out from the routing hole 98 is accommodated in the routing groove 99 and the front bearing outer ring presser 53 is attached. Thereby, the wiring 83 can be connected to the sensor 103 after the sensor 103 is attached to the housing 50.

(10th Embodiment)
FIG. 28 is a cross-sectional view of the main part of the spindle device according to the tenth embodiment of the present invention. A sensor 82 (that is, a resin sensor case) incorporated in the spindle device 10 of the present embodiment has flange portions 82d and 82d extending from the outer peripheral surface of the large diameter portion 82a toward both sides in the axial direction.

  A hole 82da is provided in the flange portion 82d, and a metal reinforcing ring 120 is integrally formed therein. The reinforcing ring 120 is longer in the axial direction than the hole 82da and protrudes from the front and back surfaces of the flange portion 82d. The sensor 82 is fixed by screwing the male screw 89 into the female screw 69 of the housing 50 through the inside of the reinforcing ring 120.

  As described above, when the sensor 82 is fixed to the housing 50 by the flange portions 82 d and 82 d provided on the sensor 82 without using the fixing jig 88, the reinforcing ring 120 is not provided and the flange portion 82 d is directly connected with the male screw 89. If tightened, the sensor 82 made of resin may be damaged due to insufficient strength, loosened due to creep deformation, or defective due to displacement.

  On the other hand, in the sensor 82 of this embodiment, the metal reinforcing ring 120 is integrally formed in the hole 82da, so that the tightening force is transmitted to the flange portion 82d by receiving the tightening force of the male screw 89 only by the reinforcing ring 120. Can be prevented. As a result, it is possible to prevent the flange portion 82d from being damaged, loosened due to creep deformation, occurrence of problems due to displacement, and the like.

In the sensor 82 of the present embodiment, the flange portions 82d and 82d are extended from the large diameter portion 82a toward both sides in the axial direction. However, the shape is not necessarily limited thereto. For example, the flange portion 82d may be provided only at one location in the axial direction.
Other configurations and operations are the same as those in the first embodiment.

In addition, this invention is not limited to each embodiment and modification which were mentioned above, A deformation | transformation, improvement, etc. are possible suitably. Moreover, each embodiment and modification can be applied in combination within a feasible range.
For example, as shown in FIG. 29, the spindle device 10 of the present invention can be similarly applied to a housing 50 that does not include a cooling oil groove. In this case, an O-ring that is attached to the large-diameter portion 82a of the sensor 82. Can be omitted.
In addition, as shown in FIG. 30, the wiring 83 is led out from the upper surface of the large-diameter portion 82a, so that it is not necessary to provide a wiring hole, which is advantageous in processing.

  Furthermore, as shown in FIG. 31, if a wireless sensor 111 capable of outputting a detection signal wirelessly is used instead of the sensors 82 and 103 with wiring, processing of the wiring hole in the housing 50 becomes unnecessary.

  Further, as shown in FIG. 32, the encoder 84 is disposed between the inner ring 32 of the front bearing 30 disposed on the side opposite to the tool and the step portion 11a of the rotary shaft 11 so as to be positioned in the axial direction of the front bearing 30. You may make it provide in the outer peripheral surface of the inner ring spacer 112 for adjustment which adjusts. In this case, the sensor 82 passes through the through-hole 113a of the outer ring spacer 113 for adjustment disposed between the outer ring 31 of the front bearing 30 and the step portion 50c of the housing 50, and is on the detected surface of the encoder 84. Opposed.

  Furthermore, in each of the embodiments described above, the encoder 84 is configured by the inner ring spacer 81, but as shown in FIG. 33, the inner ring 22 of the front bearing 20 disposed on the tool side instead of the inner ring spacer 81. May be formed so as to extend into the space of the inner ring spacer 81, and a C-shaped encoder 84 similar to the above embodiment may be formed directly on the outer peripheral surface of the inner ring 22. The encoder 84 may be formed wide so that the inner ring 32 of the front bearing 30 disposed on the side opposite to the tool is replaced with the inner ring spacer 81 and directly formed on the outer peripheral surface of the inner ring 32.

  Even in such a configuration, the sensor 82 extends from the through-hole 54a formed in the outer ring spacer 54 and is disposed to face the detection surface of the encoder 84. Therefore, the existing space can be provided without providing a new dedicated space. The sensor unit can be disposed on the sensor, and the sensor-equipped bearing device can be reduced in size. In particular, as shown in FIG. 4 of the first embodiment, the nozzle 82b is further formed in the outer ring spacer 54, and the oil supply nozzle 67 is provided in the nozzle hole 54b, so that the sensor 82 and the oil supply nozzle 67 are compact. Can be arranged.

In each of the above-described embodiments and modifications, the angular bearings are described as being combined on the back surface, but the present invention is not limited to this and may be a front surface combination. Further, the number of rows of angular bearings of the front bearing and the direction of combination are not limited.
Furthermore, the encoder of the present invention only needs to be configured by a rotating spacer, and when the inner ring is a stationary bearing ring and the outer ring is a rotating bearing ring, the encoder is configured as an outer ring spacer as a rotating spacer. May be. The bearing device according to the present invention includes a spindle device of a machine tool, a rotary table of a machine tool, a rotary member such as a ball screw, a railway vehicle, an aircraft, and an automobile supported by a bearing, and an axial load is applied to the rotary member. It is applicable to the place where it acts.

  In addition, the spindle device 10 of the present embodiment capable of measuring the axial load of the spindle shaft can be incorporated and applied to a machine tool, and is mounted on, for example, a portal machining center 201 as shown in FIG. Specifically, in the portal machining center 201, a table 203 is supported on a bed 202 so as to be movable in the X-axis direction, and a pair of columns 204 are erected on both sides of the bed 202. A cross rail 205 is installed on the upper end of the column 204, and a saddle 206 is provided on the cross rail 205 so as to be movable in the Y-axis direction. The saddle 206 also supports a ram 207 that can be raised and lowered in the Z-axis direction. A spindle that holds the spindle device 10 at the lower end of the ram 207 so as to be able to rotate and drive around the Y axis and the Z axis. A head 208 is attached. A tilt mechanism (not shown) is provided in the two support arms 208a of the spindle head 208, and the spindle device 10 is rotationally indexed around the Y axis via the bracket 209 by this tilt mechanism.

10 Spindle device 11 Rotating shaft (Rotating member, Spindle shaft)
20 Angular contact ball bearing (front bearing)
21 Outer ring (stationary ring)
22 Inner ring (Rotating raceway)
23 balls (rolling elements)
30 Angular contact ball bearing (front bearing)
31 Outer ring (stationary track theory)
32 Inner ring (rotation side trajectory)
33 balls (rolling elements)
50 Housing (stationary member)
54 Outer ring spacer (static side spacer)
54a Through hole 80 Sensor unit 81 Inner ring spacer (rotating side spacer)
82 Sensor 84 Encoder 85 Combined part for detection 86 Personalized part 93 Convex part (first detected part)
94 Concave portion (second detected portion)
90 Magnetic sensor (detector)
103 sensor 111 wireless sensor (sensor)

Claims (6)

The stationary side race ring fitted and fixed to the stationary member, the rotational side race ring fitted and fixed to the rotary member, and the stationary side raceway of the stationary side raceway and the rotational side raceway of the rotary side raceway A bearing provided with a plurality of rolling elements movably arranged;
A rotation side spacer that is disposed on the side of the rotation side raceway and rotates together with the rotation side raceway;
An encoder in which the characteristics of the detected surface change alternately in the circumferential direction, and a sensor unit that is arranged opposite to the detected surface of the encoder and detects a change in the characteristics of the detected surface. A bearing device comprising:
The encoder is constituted by the rotating side spacer,
The detected surface of the encoder comprises a single row in the axial direction where the pitch of the characteristic that changes in the circumferential direction continuously changes in the axial direction ,
The sensor has a stepped cylindrical shape composed of a large diameter portion and a small diameter portion, and a detection portion is provided at the tip of the small diameter portion,
The stationary member has a sensor mounting hole including a large-diameter hole corresponding to the large-diameter portion and a small-diameter hole corresponding to the small-diameter portion, and a surface of the stationary member is provided with an edge of the large-diameter hole. A concave groove is formed,
In the sensor inserted into the sensor mounting hole, a step between the large diameter portion and the small diameter portion engages a step between the large diameter hole and the small diameter hole, and an upper surface of the large diameter portion is The stationary member is held by one end of a fixing jig fitted and fixed in the concave groove and positioned in the radial direction so that the detection portion at the tip of the small diameter portion faces the detection surface of the encoder. A bearing device that is fixed . The bearing comprises a pair of bearings arranged to position the axial position of the rotating member;
2. The bearing device according to claim 1, wherein the rotation side spacer constituting the encoder is disposed between the rotation side races of the pair of bearings. Between the stationary side track theory of the pair of bearings, a stationary side spacer is disposed,
The bearing device according to claim 2, wherein the sensor extends from a through hole formed in the stationary side spacer and is disposed to face the detected surface of the encoder. The stationary side race ring fitted and fixed to the stationary member, the rotational side race ring fitted and fixed to the rotary member, and the stationary side raceway of the stationary side raceway and the rotational side raceway of the rotary side raceway A bearing provided with a plurality of rolling elements movably arranged;
An encoder in which the characteristics of the detected surface change alternately in the circumferential direction, and a sensor unit that is arranged opposite to the detected surface of the encoder and detects a change in the characteristics of the detected surface. A bearing device comprising:
The detected surface of the encoder has a portion in which the pitch of the characteristic that changes in the circumferential direction continuously changes in the axial direction, and is configured in a single row in the axial direction.
The sensor has a stepped cylindrical shape composed of a large diameter portion and a small diameter portion, and a detection portion is provided at the tip of the small diameter portion,
The stationary member has a sensor mounting hole including a large-diameter hole corresponding to the large-diameter portion and a small-diameter hole corresponding to the small-diameter portion, and a surface of the stationary member is provided with an edge of the large-diameter hole. A concave groove is formed,
In the sensor inserted into the sensor mounting hole, a step between the large diameter portion and the small diameter portion engages a step between the large diameter hole and the small diameter hole, and an upper surface of the large diameter portion is The stationary side is held at one end of a fixing jig fitted and fixed in the concave groove and positioned in the radial direction, and the detection portion at the tip of the small diameter portion is disposed on the side of the stationary side race ring. A bearing device, wherein the bearing device extends from a through hole formed in a spacer and is fixed to the stationary member so as to face the detected surface of the encoder. Claim 1 includes a bearing device according to any one of 4, a spindle device of machine tool, wherein the axial load of the spindle shaft which is the rotating member is measurable. A machine tool comprising the spindle device according to claim 5 .

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