Method for assembling a rolling bearing device with a sensor, mounting jig, and rolling bearing device with a sensor

Abstract

This method for assembling a sensor-equipped rolling bearing device 1, which is provided with a housing 2, a rolling bearing 3, and a sensor 4 having a wire 42, includes: an assembly step for fitting an outer peripheral surface 31d of an outer race 31 of the rolling bearing 3 to an inner peripheral surface 22 of the housing 2, thereby assembling the rolling bearing 3 into the housing 2; a holding step for holding the sensor 4 at the distal end of a first jig 71; and, after both the assembly step and the holding step, an attachment step for inserting the distal end of the first jig 71 from the outer-peripheral side of the housing 2 into an insertion hole 21 formed passing through the housing 2 in the radial direction, and attaching the sensor 4 in a facing position where the sensor 4 faces the insertion hole 21 in the outer peripheral surface 31d of the outer race 31.

Description

[Technical Field]

[0001] The present invention relates to a method for assembling a sensor-equipped rolling bearing device, a mounting jig, and a sensor-equipped rolling bearing device. [Background technology]

[0002] In recent years, with the increasing need to monitor the condition of machinery and equipment, there has been a demand for rolling bearings to also be equipped with sensing functions. For example, if it were possible to detect the cutting load applied to the rolling bearing that supports the main spindle in a machine tool, it would be possible to reduce tool wear by optimizing machining conditions, shorten machining time, and prevent breakdowns by detecting abnormal machining. In Patent Document 1, multiple strain gauges are attached to annular grooves formed on the outer peripheral surface of the outer ring of a rolling bearing, and each strain gauge detects the strain of the outer ring when a load is applied to the rolling bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-61268 Summary of the Invention [Problem to be solved by the invention]

[0004] In the rolling bearing described in Patent Document 1, there is a risk that the wiring of the strain gauges may break when the rolling bearing to which the strain gauges are attached is installed into mechanical equipment. One possible way to prevent such breaks is to attach the strain gauges to the outer ring of the rolling bearing after the rolling bearing has been installed into the mechanical equipment, but in that case, the strain gauges would be attached from the outside of the housing of the mechanical equipment, making it difficult to attach them in the correct position.

[0005] The present invention has been made in view of the above circumstances, and makes it possible to accurately attach a sensor to the outer ring of a rolling bearing while preventing the wiring of the sensor from breaking. [Means for solving the problem]

[0006] The method for assembling a sensor-equipped rolling bearing device of the present invention is a method for assembling a sensor-equipped rolling bearing device comprising a cylindrical housing, a rolling bearing having an outer ring whose outer surface is fitted into the inner surface of the housing, and a sensor having wiring attached to the outer surface of the outer ring for detecting distortion of the outer ring, and includes an assembly step of incorporating the rolling bearing into the housing by fitting the outer surface of the outer ring into the inner surface of the housing; a holding step of holding the sensor at the tip of a first jig; and, after both the assembly step and the holding step, an installation step of inserting the tip of the first jig into an insertion hole formed radially through the housing from the outer peripheral side of the housing, and installing the sensor in an opposing position facing the insertion hole on the outer surface of the outer ring.

[0007] The mounting jig of the present invention is an mounting jig for mounting a sensor having wiring on the outer surface of an outer ring of a rolling bearing, in order to detect distortion of the outer ring, with the outer surface of the outer ring fitted into the inner surface of a cylindrical housing, and is provided with a first jig whose tip is made of an elastic material, and which is capable of holding the sensor on its tip surface and is insertable, with the sensor held in place, from the outer side of the housing into an insertion hole formed radially through the housing.

[0008] The sensor-equipped rolling bearing device of the present invention comprises a cylindrical housing having an insertion hole formed therethrough in the radial direction, a rolling bearing having an outer ring whose outer surface is fitted to the inner surface of the housing, an elastic member inserted into the insertion hole, a sensor having wiring and held by the elastic member on the inner side of the housing relative to the elastic member in the insertion hole, and a blocking member that blocks the opening of the insertion hole on the outer side of the housing, and the sensor is attached in an opposing position facing the insertion hole on the outer surface of the outer ring in order to detect distortion of the outer ring. [Effects of the Invention]

[0009] According to the present invention, it is possible to accurately attach a sensor to the outer ring of a rolling bearing while preventing the wiring of the sensor from breaking. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view showing a sensor-equipped rolling bearing device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view showing a rolling bearing. [Figure 3] FIG. 4 is a cross-sectional view showing the periphery of an insertion hole of a housing. [Figure 4] FIG. 2 is a perspective view showing a first jig. [Figure 5] FIG. 4 is a perspective view showing a second jig. [Figure 6] FIG. 10 is a perspective view showing a state in which the nut jig and the third jig are used. [Figure 7] 4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. [Figure 8] 4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. [Figure 9] 4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. [Figure 10] 4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. [Figure 11] 4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. [Figure 12]4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. [Figure 13] 4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. [Figure 14] 4A to 4C are explanatory diagrams illustrating a method for assembling the sensor-equipped rolling bearing device. DETAILED DESCRIPTION OF THE INVENTION

[0011] First, the contents of the embodiment will be listed and explained. <Outline of the embodiment> (1) An embodiment of a method for assembling a sensor-equipped rolling bearing device includes a cylindrical housing, a rolling bearing having an outer ring whose outer peripheral surface is fitted against the inner peripheral surface of the housing, and a sensor having wiring attached to the outer peripheral surface of the outer ring for detecting distortion of the outer ring, and includes an assembly process for incorporating the rolling bearing into the housing by fitting the outer peripheral surface of the outer ring against the inner peripheral surface of the housing, a holding process for holding the sensor at the tip of a first jig, and an attachment process for, after both the assembly process and the holding process, inserting the tip of the first jig from the outer peripheral side of the housing into an insertion hole formed radially through the housing, and attaching the sensor to a position facing the insertion hole on the outer peripheral surface of the outer ring.

[0012] According to the above embodiment, the sensor is attached to the outer ring of the rolling bearing after the rolling bearing is incorporated into the housing, which prevents the sensor wiring from breaking during assembly of the sensor-equipped rolling bearing device. Furthermore, by holding the sensor at the tip of the first jig and inserting the tip into the insertion hole in the housing, the sensor can be attached at a position on the outer peripheral surface of the outer ring that faces the insertion hole. This prevents the sensor from being attached anywhere other than the opposite position on the outer ring, allowing the sensor to be accurately attached to the outer peripheral surface of the outer ring.

[0013] (2) It is preferable that the tip of the first jig is made of an elastic member, and in the holding process, one side of the sensor is held on the tip surface of the elastic member, and adhesive is applied to the other side of the sensor opposite to the one side, and in the mounting process, the sensor held on its tip surface is pressed against the opposing position by the elastic member inserted into the insertion hole, thereby fixing the sensor to the opposing position with the adhesive. In this case, when the sensor is attached to the outer peripheral surface of the outer ring with adhesive, the sensor is pressed by the elastic member, thereby preventing damage to the sensor.

[0014] (3) An embodiment of the mounting jig is a mounting jig for mounting a sensor having wiring on the outer peripheral surface of an outer ring of a rolling bearing in order to detect distortion of the outer ring when the outer peripheral surface of the outer ring is fitted into the inner peripheral surface of a cylindrical housing, and includes a first jig having a tip made of an elastic material, which is capable of holding the sensor on its tip surface and is capable of being inserted from the outer peripheral side of the housing into an insertion hole formed radially through the housing while holding the sensor.

[0015] According to the above embodiment, after fitting the outer peripheral surface of the outer ring to the inner peripheral surface of the housing, the sensor can be attached to the outer peripheral surface of the outer ring by holding the sensor at the tip of the first jig and inserting the tip into the insertion hole of the housing. In other words, the sensor can be attached to the outer ring of the rolling bearing after the rolling bearing is incorporated into the housing, which prevents the sensor wiring from breaking during assembly of the sensor-equipped rolling bearing device. Furthermore, by inserting the sensor into the insertion hole of the housing, the sensor can be attached to a position on the outer peripheral surface of the outer ring that faces the insertion hole. This ensures that the sensor is attached only in the opposite position on the outer ring, allowing the sensor to be accurately attached to the outer peripheral surface of the outer ring. Furthermore, for example, when the sensor is pressed against the outer peripheral surface of the outer ring and fixed with an adhesive, the sensor can be pressed by an elastic member, which prevents the sensor from being damaged.

[0016] (4) The mounting jig further includes a cylindrical second jig having a male thread on its outer periphery that is fastened to a female thread formed in the insertion hole, and the elastic member can be inserted into the second jig while holding the sensor, and the inner surface of the second jig preferably serves as a guide surface that guides the insertion of the elastic member. In this case, the second jig can be inserted into the insertion hole and fixed by tightening the male thread of the second jig into the female thread of the insertion hole. In this state, the elastic member holding the sensor can be inserted into the second jig, and the guide surface of the second jig can guide the insertion of the elastic member. This allows the sensor to be attached more accurately to the outer peripheral surface of the outer ring.

[0017] (5) The first jig has a cylindrical jig body that can be inserted into the second jig, and the elastic member that is removably attached to the axial tip of the jig body, and it is preferable that a first notch is formed in a part of the circumference of the jig body over the entire axial length for passing the sensor wiring radially through the jig body. In this case, the sensor wiring held by the elastic member can be positioned radially inward of the jig body through the first notch, further preventing the sensor wiring from breaking when the jig body and elastic member are inserted into the second jig. Also, even if the jig body is removed from the second jig after the sensor is attached to the outer peripheral surface of the outer ring, the sensor wiring remains positioned radially inward of the jig body. However, according to the configuration (5) above, the jig body can be easily separated from the sensor wiring by moving the jig body so that the sensor wiring passes through the first notch.

[0018] (6) It is preferable that a second notch for passing the wiring of the sensor in the radial direction of the second jig is formed in a part of the circumferential direction of the second jig over the entire axial length. After the sensor is attached to the outer peripheral surface of the outer ring, even if the jig body is removed from the second jig and the second jig is removed from the insertion hole, the sensor wiring remains disposed on the radially inner side of the second jig. However, according to the configuration of (6) above, by moving the second jig so that the sensor wiring passes through the second notch, the second jig can be easily separated from the sensor wiring.

[0019] (7) It is preferable that the second jig has a protrusion that protrudes from the insertion hole when a portion of the male screw is tightened into the female screw of the insertion hole, and that the mounting jig further comprises a nut jig having a female screw that is tightened onto the other portion of the male screw on the outer periphery of the protrusion, and a third jig that is inserted into the first notch and the second notch when the jig body is inserted into the second jig to restrict circumferential movement of the jig body relative to the second jig.

[0020] In this case, by fastening the female thread of the nut jig to the male thread of the protruding portion of the second jig protruding from the insertion hole of the housing, the female thread of the insertion hole and the female thread of the nut jig function as the respective female threads of the double nut. This fixes the fastening position of the second jig relative to the insertion hole, so the second jig is held with the second notch facing a predetermined direction. Furthermore, when inserting the jig body of the first jig into the second jig, the first notch is aligned with the second notch, and a third jig is inserted into both notches, restricting circumferential movement of the first jig relative to the second jig. Therefore, the tip of the first jig can be inserted into the second jig with the first notch aligned with the second notch, which is held facing a predetermined direction. This allows the sensor held at the tip of the first jig to be attached to the outer peripheral surface of the outer ring with its orientation accurately aligned.

[0021] (8) It is preferable that a third notch for passing the wiring of the sensor in the radial direction of the nut jig is formed in a part of the circumferential direction of the nut jig over the entire axial length. After the sensor is attached to the outer peripheral surface of the outer ring, even if the nut jig is removed from the second jig, the sensor wiring remains disposed radially inside the nut jig. However, according to the configuration of (8) above, the nut jig can be easily separated from the sensor wiring by moving the nut jig so that the sensor wiring passes through the third notch.

[0022] (9) An embodiment of a sensor-equipped rolling bearing device includes a cylindrical housing having an insertion hole formed therethrough in the radial direction, a rolling bearing having an outer ring whose outer surface is fitted to the inner surface of the housing, an elastic member inserted into the insertion hole, a sensor having wiring and held by the elastic member on the inner side of the housing relative to the elastic member in the insertion hole, and a blocking member that blocks the opening of the insertion hole on the outer side of the housing, and the sensor is attached at an opposing position facing the insertion hole on the outer surface of the outer ring to detect distortion of the outer ring.

[0023] According to the above embodiment, after fitting the outer peripheral surface of the outer ring to the inner peripheral surface of the housing, the sensor can be attached to the outer peripheral surface of the outer ring by inserting the elastic member into the insertion hole of the housing while the sensor is held by the elastic member. In other words, the sensor can be attached to the outer ring of the rolling bearing after the rolling bearing is incorporated into the housing, which makes it possible to prevent the sensor wiring from being broken during assembly of the sensor-equipped rolling bearing device. Furthermore, by inserting the sensor into the insertion hole of the housing, the sensor can be attached to a position on the outer peripheral surface of the outer ring that faces the insertion hole. As a result, the sensor will not be attached anywhere other than the opposite position on the outer ring, so the sensor can be accurately attached to the outer peripheral surface of the outer ring.

[0024] Furthermore, when the sensor is pressed against the outer peripheral surface of the outer ring and fixed with an adhesive, for example, the elastic member can press the sensor, thereby preventing damage to the sensor. Furthermore, when the sensor is inserted into the insertion hole of the housing, the opening of the insertion hole can be blocked with the blocking member, preventing water flowing along the sensor wiring from entering the insertion hole.

[0025] <Details of the embodiment> Preferred embodiments will now be described with reference to the drawings. [Sensor-equipped rolling bearing device] 1 is a front view showing a sensor-equipped rolling bearing device according to an embodiment of the present invention. The sensor-equipped rolling bearing device 1 is used, for example, to support the main shaft (spindle) 10 of a machine tool. The sensor-equipped rolling bearing device 1 comprises a housing 2, a rolling bearing 3, a plurality of sensors 4 (six in the illustrated example), and the same number of blocking members 5 as the sensors 4.

[0026] Housing 2 is formed in a cylindrical shape and surrounds main shaft 10. Housing 2 has a plurality of insertion holes 21 (six in the illustrated example) that penetrate radially and are spaced apart at predetermined intervals in the circumferential direction. Rolling bearing 3 is disposed between housing 2 and main shaft 10.

[0027] Fig. 2 is a cross-sectional view of the rolling bearing 3 taken along the line II in Fig. 1. In Figs. 1 and 2, the rolling bearing 3 comprises an outer ring 31 which is a fixed ring, an inner ring 32 which is a rotating ring, a plurality of balls (rolling elements) 33, and an annular cage 34. The rolling bearing 3 of this embodiment is an angular contact ball bearing. Note that the cage 34 is not shown in Fig. 1.

[0028] An outer ring raceway 31a, on which the balls 33 roll, is formed on the inner peripheral surface of the outer ring 31. The outer ring 31 has a shoulder 31b and a counterbore 31c on both axial sides of the outer ring raceway 31a. In this embodiment, the inner diameter of the shoulder 31b is smaller than the inner diameter of the counterbore 31c. An outer peripheral surface 31d of the outer ring 31 is fitted into the inner peripheral surface 22 of the housing 2.

[0029] The inner ring 32 is disposed radially inward of the outer ring 31 and concentric with the outer ring 31. An arc-shaped inner ring raceway 32a, on which the balls 33 roll, is formed on the outer peripheral surface of the inner ring 32. The inner ring 32 has a first shoulder 32b and a second shoulder 32c on both axial sides of the inner ring raceway 32a. In this embodiment, the outer diameters of the first shoulder 32b and the second shoulder 32c are the same. An inner peripheral surface 32d of the inner ring 32 is fitted onto the outer peripheral surface 10a of the spindle 10.

[0030] A plurality of balls 33 are arranged in the annular space between the outer ring 31 and the inner ring 32. When the inner ring 32 rotates, the plurality of balls 33 roll on the outer ring raceway 31a and the inner ring raceway 32a while being held by the cage 34. The cage 34 has a pair of annular bodies 35 and a plurality of pillars 36 connecting these annular bodies 35. The pillars 36 are arranged at equal intervals in the circumferential direction, and pockets 37 for accommodating each ball 33 are formed between adjacent pairs of pillars 36, 36 and between the pair of annular bodies 35, 35. In this way, the cage 34 holds the plurality of balls 33 at equal intervals in the circumferential direction.

[0031] 3 is a cross-sectional view showing the periphery of the insertion hole 21 of the housing 2. Hereinafter, in this specification, the outer circumferential side of the housing 2 will also be referred to as the "outside" and the inner circumferential side of the housing 2 will also be referred to as the "inside." Each insertion hole 21 has, in order from the inside to the outside, a first hole portion 21a, a second hole portion 21b, and a third hole portion 21c. The diameter of the first hole portion 21a is set to a size that allows a first jig 71 (described below) and the sensor 4 to be inserted therein.

[0032] The second hole portion 21b is formed to have a larger diameter than the first hole portion 21a. An annular first step surface 21d is formed between the first hole portion 21a and the second hole portion 21b. A female thread 21e is formed on the inner periphery of the second hole portion 21b. The third hole portion 21c is formed to have a larger diameter than the second hole portion 21b. An annular second step surface 21f is formed between the second hole portion 21b and the third hole portion 21c.

[0033] An elastic member 73 is inserted into the first hole portion 21a of each insertion hole 21. The elastic member 73 is formed in a cylindrical shape from an elastic material such as rubber. The elastic member 73 has a large diameter portion 73a and a small diameter portion 73b formed with a smaller diameter than the large diameter portion 73a. The large diameter portion 73a is positioned more inward in the first hole portion 21a than the small diameter portion 73b. The outer diameter of the large diameter portion 73a is slightly smaller than the hole diameter of the first hole portion 21a of the housing 2. The outer diameter of the small diameter portion 73b is slightly smaller than the inner diameter of a jig main body 72 described below (see FIG. 10).

[0034] The large diameter portion 73a of the elastic member 73 holds a sensor 4 that detects strain in the outer ring 31. The sensor 4 has a strain gauge 41 and wiring 42. The strain gauge 41 is fixed to an inner end face (tip face) 73c of the large diameter portion 73a. In this embodiment, one face 41a of the strain gauge 41 is adhered to the end face 73c of the large diameter portion 73a with an adhesive. The strain gauge 41 is formed to a size that fits within the outer shape of the large diameter portion 73a.

[0035] The strain gauge 41 is disposed in the first hole portion 21a of the insertion hole 21 together with the elastic member 73. The other surface 41b of the strain gauge 41 opposite to the one surface 41a is attached to a position facing the insertion hole 21 on the outer peripheral surface 31d of the outer ring 31. In this embodiment, the other surface 41b of the strain gauge 41 is adhered to the facing position with an adhesive.

[0036] The wiring 42 has a pair of lead wires 43 extending from the strain gauge 41 and an insulating portion 44 that covers these lead wires 43. Each lead wire 43 wraps around the radially outer side of the elastic member 73 and extends to the outside of the housing 2 from an outer opening 21g (see FIG. 5) of the insertion hole 21 (third hole portion 21c). The insulating portion 44 covers the portion of the pair of lead wires 43 that extends from the portion located in the second hole portion 21b to the outside of the housing 2.

[0037] The outer opening 21g of the insertion hole 21 is closed by a closing member 5. The closing member 5 includes a first screw member 51, a second screw member 52, a first seal member 53, and a second seal member 54. The first screw member 51 has a first head 51a and a first shaft portion 51b. A male thread 51c is formed on the outer periphery of the first shaft portion 51b, except for a portion on the first head 51a side. The male thread 51c is fastened to the female thread 21e of the second hole portion 21b. The outer diameter of the first head 51a is larger than the hole diameter of the third hole portion 21c. An inner end face 51d of the first head 51a abuts against the outer circumferential surface 23 of the housing 2.

[0038] A through hole 51e, into which the insulating portion 44 of the wiring 42 is inserted, is formed axially through the center of the first screw member 51. The through hole 51e has, from the inside to the outside, a small hole portion 51f, a step surface 51g, and a large hole portion 51h. A female thread 51i is formed on the inner periphery of the large hole portion 51h, except for a portion on the step surface 51g side. The diameter of the small hole portion 51f is smaller than the diameter of the large hole portion 51h and slightly larger than the outer diameter of the insulating portion 44. The step surface 51g is formed in an annular shape between the small hole portion 51f and the large hole portion 51h.

[0039] The second screw member 52 has a second head portion 52a and a second shaft portion 52b. A male thread 52c is formed on the outer periphery of the second shaft portion 52b. The male thread 52c is fastened to the female thread 51i of the first screw member 51. The outer diameter of the second head portion 52a is smaller than the outer diameter of the first head portion 51a and larger than the diameter of the large hole portion 51h of the first screw member 51. An inner end surface 52d of the second head portion 52a abuts against an outer end surface 51j of the first head portion 51a.

[0040] The first seal member 53 is disposed in the third hole portion 21c of the insertion hole 21, radially outward of the first shaft portion 51b. The first seal member 53 of this embodiment is a rubber O-ring (see also FIG. 14). The first seal member 53 is compressed between the end face 51d of the first head portion 51a and the second step surface 21f of the insertion hole 21. As a result, the first seal member 53 is in close contact with the inner circumferential surface of the third hole portion 21c and the outer circumferential surface of the first shaft portion 51b (the portion outside the male thread 51c), thereby sealing between these circumferential surfaces.

[0041] The second seal member 54 is disposed inside the large hole portion 51h of the first screw member 51. The second seal member 54 in this embodiment is a rubber O-ring (see also FIG. 14). The second seal member 54 is compressed between the inner end face of the second shaft portion 52b and the stepped surface 51g of the first screw member 51. As a result, the second seal member 54 is in close contact with the outer peripheral surface of the insulating portion 44 of the wiring 42 and the inner peripheral surface of the large hole portion 51h (the portion inside the female thread 51i), thereby sealing between these peripheral surfaces.

[0042] [Mounting jig] Next, we will explain the mounting jig used when assembling the sensor-equipped rolling bearing device 1. The mounting jig is used when mounting the sensor 4 to the outer peripheral surface 31d of the outer ring 31 of the rolling bearing 3 in a state where the outer peripheral surface 31d is fitted into the inner peripheral surface 22 of the housing 2. Figure 4 is a perspective view showing a first jig 71 provided in the mounting jig 70. For ease of explanation, the lower end of the first jig 71 in Figure 4 will be referred to as the "tip end" and the upper end of the first jig 71 in Figure 4 will be referred to as the "base end".

[0043] The first jig 71 holds the sensor 4 at its tip. Figure 4 shows the state in which the sensor is held at the tip of the first jig 71. The first jig 71 has a jig main body 72 and the elastic member 73 described above. The jig main body 72 is formed in a cylindrical shape. The outer diameter of the jig main body 72 is approximately the same as the outer diameter of the large diameter portion 73a of the elastic member 73, and is slightly smaller than the hole diameter of the first hole portion 21a of the housing 2 (see Figure 10). The inner diameter of the jig main body 72 is approximately the same as the outer diameter of the small diameter portion 73b of the elastic member 73.

[0044] The small diameter portion 73b of the elastic member 73 is fitted onto the inner periphery of the axial tip of the jig body 72. This allows the elastic member 73 to be detachably attached to the axial tip of the jig body 72. Referring to Fig. 10, the axial length L1 of the first jig 71 is greater than the sum of the depth H1 of the insertion hole 21 of the housing 2 and the axial length L3 of the protrusion 74b (described below).

[0045] 4, a first notch 72a is formed over the entire axial length of the jig body 72 in a portion of the circumferential direction. The circumferential width W1 of the first notch 72a is large enough to allow an intermediate portion of the wiring 42 of the sensor 4 to pass radially through the jig body 72. With the elastic member 73 attached to the jig body 72, the lead wire 43 extending from the strain gauge 41 wraps around the radially outer side of the elastic member 73, passes through the first notch 72a together with the insulating portion 44, and is positioned radially inside the jig body 72.

[0046] FIG. 5 is a perspective view showing a second jig 74 included in the mounting jig 70. The second jig 74 is inserted into the insertion hole 21 of the housing 2. The second jig 74 is formed in a cylindrical shape. The outer diameter of the second jig 74 is larger than the diameter of the first hole portion 21a of the housing 2 and smaller than the diameter of the third hole portion 21c. A male thread 74a is formed on the outer periphery of the second jig 74 over the entire axial length thereof and is fastened to the female thread 21e of the insertion hole 21. Referring to FIG. 10, the axial length L2 of the second jig 74 is larger than the total depth H2 of the second hole portion 21b and the third hole portion 21c of the insertion hole 21.

[0047] With the above configuration, the second jig 74 is fixed in a state where it is inserted into the insertion hole 21, with part of the male thread 74a being tightened into the female thread 21e of the insertion hole 21. With part of the male thread 74 tightened into the female thread 21e, the second jig 74 has a protruding portion 74b that protrudes radially outward from the insertion hole 21 from the housing 2. The other part of the male thread 74a formed on the outer periphery of the protruding portion 74b is not inserted into the insertion hole 21 and is exposed to the outside of the housing 2.

[0048] The inner diameter of the second jig 74 is slightly larger than the outer diameter of the jig body 72 and the outer diameter of the large diameter portion 73a of the elastic member 73. This allows the jig body 72 and the large diameter portion 73a of the elastic member 73 to be inserted into the second jig 74. An inner peripheral surface 74c of the second jig 74 serves as a guide surface that guides the insertion of the first jig 71 (the jig body 72 and the large diameter portion 73a).

[0049] 5, a second notch 74d is formed over the entire axial length of the second jig 74 in a portion of the circumference of the second jig 74. The circumferential width W2 of the second notch 74d is large enough to allow the middle portion of the wiring 42 of the sensor 4 to pass through the second jig 74 in the radial direction (see FIG. 6). In this embodiment, the width W2 of the second notch 74d is the same as the width W1 of the first notch 72a.

[0050] 6 is a perspective view showing a state in which a nut jig 75 and a third jig 76 provided in the mounting jig 70 are used. The nut jig 75 is attached to the protruding portion 74b of the second jig 74 inserted into the insertion hole 21 of the housing 2. A female thread 75a is formed on the inner periphery of the nut jig 75 (see FIG. 10). The female thread 75a is tightened onto the male thread 74a on the outer periphery of the protruding portion 74b.

[0051] The nut jig 75 is tightened until its axial end face abuts against the outer peripheral surface 23 of the housing 2. By tightening the female thread 75a of the nut jig 75 onto the male thread 74a of the protrusion 74b in this manner, the female thread 21e of the insertion hole 21 and the female thread 75a of the nut jig 75 function as the respective female threads of the double nut. This makes it possible to fix the tightening position of the second jig 74 relative to the insertion hole 21, and to hold the second notch 74d of the second jig 74 facing in a predetermined direction.

[0052] A third notch 75b is formed over the entire axial length of the nut jig 75 in a portion of the circumference of the nut jig 75. The circumferential width W3 of the third notch 75b is large enough to allow the middle portion of the wiring 42 of the sensor 4 to pass through the nut jig 75 in the radial direction.

[0053] The third jig 76 is used when inserting the jig body 72 of the first jig 71 into the second jig 74. In this embodiment, the third jig 76 is a pin member formed in a cylindrical shape. The outer diameter of the third jig 76 is slightly smaller than the widths W1 and W2 of the first and second cutouts 72a and 74d. This allows the third jig 76 to be inserted into both cutouts 72a and 74d by aligning the first cutout 72a with the second cutout 74d.

[0054] In this embodiment, the third jig 76 is inserted into both notches 72a, 74d with the axial direction of the third jig 76 facing the radial direction of the second jig 74 (first jig 71). This allows the jig body 72 to be inserted into the second jig 74 while restricting circumferential movement of the jig body 72 relative to the second jig 74.

[0055] [Method for assembling a rolling bearing device with a sensor] Next, we will explain how to assemble the sensor-equipped rolling bearing device 1 using the mounting jig 70. First, as shown in Fig. 7, the outer peripheral surface 31d of the outer ring 31 is fitted to the inner peripheral surface 22 of the housing 2, and the inner peripheral surface 32d of the inner ring 32 is fitted to the outer peripheral surface 10a of the main shaft 10, thereby incorporating the rolling bearing 3 between the housing 2 and the main shaft 10 (assembly step).

[0056] Next, as shown in FIG. 5, a second jig 74 is inserted into the insertion hole 21 of the housing 2. Specifically, the male thread 74a of the second jig 74 is tightened into the female thread 21e of the insertion hole 21. Then, just before the second jig 74 is completely tightened into the insertion hole 21, tightening of the second jig 74 is stopped with the second notch 74d facing in a predetermined direction. In this state, as shown in FIG. 8, a nut jig 75 is tightened onto the protrusion 74b of the second jig 74. This fixes the tightened position of the second jig 74 relative to the insertion hole 21, and the second jig 74 is held in the insertion hole 21 with the second notch 74d facing in a predetermined direction.

[0057] Next, as shown in FIG. 4, the sensor 4 is held at the tip of the first jig 71 (holding step). Specifically, one surface 41a (see FIG. 3) of the strain gauge 41 is attached with an adhesive to a tip surface 73c of the elastic member 73 attached to the jig body 72. At this time, the strain gauge 41 is attached to the elastic member 73 so that the connection portion of the pair of lead wires 43 with the strain gauge 41 is positioned closest to the first notch 72a of the jig body 72. The wiring 42 of the sensor 4 passes through the first notch 72a from the radial outside of the elastic member 73 and is positioned on the radial inside of the jig body 72. Thereafter, an adhesive is applied to the other surface 41b of the strain gauge 41. Note that the work of attaching the strain gauge 41 to the elastic member 73 may be performed before attaching the elastic member 73 to the jig body 72.

[0058] 9, the tip of the first jig 71 is inserted into the second jig 74 from the outer periphery side of the housing 2, and the strain gauge 41 is attached to the outer periphery surface 31d of the outer ring 31 (attachment process). Specifically, the elastic member 73 and the jig body 72 holding the sensor 4 of the first jig 71 are inserted into the second jig 74 held in the insertion hole 21 from the opening on the protruding portion 74b side.

[0059] 6, the first notch 72a of the jig body 72 is aligned with the second notch 74d of the second jig 74, and the third jig 76 is inserted into both notches 72a and 74d. This allows the tip of the first jig 71 to be inserted into the second jig 74 while restricting circumferential movement of the first jig 71 relative to the second jig 74.

[0060] 9, the portions of the pair of lead wires 43 located radially outward of the elastic member 73 are positioned within the width of the second cutout 74d when inserted into the second jig 74. Therefore, when the tip end of the first jig 71 is inserted into the second jig 74, it is possible to prevent the pair of lead wires 43 from interfering with the second jig 74 and being broken.

[0061] Furthermore, with the first notch 72a aligned with the second notch 74d, which is held facing in a predetermined direction, the tip of the first jig 71 is inserted into the second jig 74. This allows the strain gauge 41 to be attached to the outer peripheral surface 31d of the outer ring 31 with the orientation of the strain gauge 41 accurately aligned.

[0062] Next, as shown in FIG. 10 , when the first jig 71 inserted into the second jig 74 is pushed toward the outer ring 31 (the lower side in FIG. 10 ), the tip of the first jig 71 is inserted into the first hole portion 21a of the insertion hole 21 while being guided by the inner peripheral surface 74c of the second jig 74. When the first jig 71 is further pushed toward the outer ring 31, the strain gauge 41 is pressed by the elastic member 73 to a position facing the insertion hole 21 (first hole portion 21a) on the outer peripheral surface 31d of the outer ring 31. As a result, the adhesive applied to the other surface 41b of the strain gauge 41 affixes and fixes the strain gauge 41 to the facing position on the outer ring 31. After the strain gauge 41 is fixed to the facing position by the adhesive, the pressing of the first jig 71 (elastic member 73) on the strain gauge 41 is released.

[0063] Next, from the state shown in Fig. 10, the portion of the jig body 72 protruding from the second jig 74 is grasped, and the jig body 72 is pulled toward the outer periphery of the housing 2 (upper side in Fig. 10). At this time, since the elastic member 73 is fixed to the strain gauge 41 affixed to the outer periphery 31d of the outer ring 31, only the jig body 72 is pulled out from the second jig 74, as shown in Fig. 11. The elastic member 73 is released from engagement with the jig body 72 and remains in the insertion hole 21 together with the strain gauge 41.

[0064] Next, from the state shown in Fig. 11, the third jig 76 is removed from the second notch 74d of the second jig 74 to obtain the state shown in Fig. 8. Then, the nut jig 75 is loosened from the second jig 74. Thereafter, the tightening of the male thread 74a of the second jig 74 relative to the female thread 21e of the insertion hole 21 is loosened, and the second jig 74 is removed from the insertion hole 21 together with the nut jig 75 as shown in Fig. 12.

[0065] Next, as shown in FIG. 13 , the jig body 72, the second jig 74, and the nut jig 75 are separated from the wire 42. Specifically, the jig body 72 is moved in a direction perpendicular to the longitudinal direction of the wire 42 (the left-right direction in FIG. 13 ) so that the wire 42, which is arranged radially inside the jig body 72, passes through the first cutout 72a. This allows the jig body 72 to be separated from the wire 42. Note that the task of separating the jig body 72 from the wire 42 may be performed before the second jig 74 is removed from the insertion hole 21.

[0066] Next, the second jig 74 and the nut jig 75 are separated from the wiring 42. Specifically, first, the nut jig 75 is rotated relative to the second jig 74 so that the third notch 75b is aligned with the second notch 74d. Then, the second jig 74 and the nut jig 75 are moved in a direction perpendicular to the longitudinal direction of the wiring 42 so that the wiring 42, which is arranged radially inside the second jig 74, passes through both the aligned notches 75b and 72d. This allows the second jig 74 and the nut jig 75 to be separated from the wiring 42.

[0067] The work of separating the second jig 74 and the nut jig 75 from the wiring 42 may be performed before the work of separating the jig body 72 from the wiring 42. Furthermore, the work of separating the second jig 74 and the nut jig 75 from the wiring 42 may be performed in a state in which the nut jig 75 is removed from the second jig 74.

[0068] Next, the outer opening 21g of the insertion hole 21 is blocked with the blocking member 5. Specifically, first, as shown in FIG. 14, the wiring 42 is inserted into the first sealing member 53, the first screw member 51, the second sealing member 54, and the second screw member 52 in this order. Next, as shown in FIG. 3, with the first sealing member 53 placed in the third hole portion 21c of the insertion hole 21, the male threads 51c of the first screw member 51 are tightened into the female threads 21e of the insertion hole 21. Thereafter, with the second sealing member 54 placed in the large hole portion 51h of the first screw member 51, the male threads 52c of the second screw member 52 are tightened into the female threads 51i of the first screw member 51.

[0069] As described above, the assembly work of the sensor-equipped rolling bearing device 1 is completed by performing the mounting work of the sensors 4 using the mounting jig 70 and the blocking work with the blocking members 5 for all of the insertion holes 21 formed in the circumferential direction of the housing 2. After the above assembly, the elastic members 73 of the first jig 71 remain in the insertion holes 21 as shown in Figure 3, thereby fulfilling the function of coating one surface 41a of the strain gauges 41. Therefore, after assembly, the elastic members 73 are configured as part of the sensor-equipped rolling bearing device 1.

[0070] [Effects of the embodiment] As described above, according to the sensor-equipped rolling bearing device 1 of this embodiment, the strain gauge 41 of the sensor 4 is attached to the outer ring 31 of the rolling bearing 3 after the rolling bearing 3 has been incorporated into the housing 2, making it possible to prevent breakage of the wiring 42 of the sensor 4 during assembly of the sensor-equipped rolling bearing device 1. Furthermore, by holding the strain gauge 41 at the tip of the first jig 71 and inserting the tip into the insertion hole 21 of the housing 2, the strain gauge 41 can be attached at a position on the outer peripheral surface 31d of the outer ring 31 that faces the insertion hole 21. As a result, the strain gauge 41 will not be attached to the outer ring 31 in any position other than the above-mentioned opposite position, and the strain gauge 41 can be accurately attached to the outer peripheral surface 31d of the outer ring 31.

[0071] Furthermore, when the strain gauges 41 are attached to the outer peripheral surface 31d of the outer ring 31 with an adhesive, the strain gauges 41 are pressed by the elastic members 73, which prevents damage to the strain gauges 41. Furthermore, the elastic members 73 serve to coat the strain gauges 41, eliminating the need for coating the strain gauges 41. Furthermore, there is no need to form grooves in the outer peripheral surface 31d of the outer ring 31 for attaching the strain gauges 41, so the strain gauges 41 can be attached accurately even to a typical rolling bearing 3.

[0072] Furthermore, by tightening the male threads 74a of the second jig 74 into the female threads 21e of the insertion hole 21, the second jig 74 is fixed in the inserted state in the insertion hole 21. By inserting the elastic member 73 holding the strain gauge 41 into the second jig 74 in this state, the inner peripheral surface 74c of the second jig 74 can guide the insertion of the elastic member 73. This allows the strain gauge 41 to be attached to the outer peripheral surface 31d of the outer ring 31 even more accurately.

[0073] Furthermore, the wiring 42 extending from the strain gauge 41 held by the elastic member 73 can be passed through the first notch 72a and positioned radially inside the jig main body 72, thereby further preventing the wiring 42 from breaking when the jig main body 72 and the elastic member 73 are inserted into the second jig 74.

[0074] Furthermore, the jig body 72 and the elastic member 73 are inserted into the second jig 74 with the first notch 72a of the jig body 72 aligned with the second notch 74d of the second jig 74. Therefore, the portions of the pair of lead wires 43 located radially outward of the elastic member 73 are inserted into the second jig 74 with the portions positioned within the width of the second notch 74d. Therefore, when the jig body 72 and the elastic member 73 are inserted into the second jig 74, it is possible to further prevent the pair of lead wires 43 from interfering with the second jig 74 and becoming disconnected.

[0075] Furthermore, by fastening the female thread 75a of the nut jig 75 to the male thread 74a of the protruding portion 74b of the second jig 74 protruding from the insertion hole 21 of the housing 2, the female thread 21e of the insertion hole 21 and the female thread 75a of the nut jig 75 function as the female threads of the double nut. This fixes the fastening position of the second jig 74 relative to the insertion hole 21, so that the second jig 74 is held with the second notch 74d facing a predetermined direction. Furthermore, when inserting the jig body 72 of the first jig 71 into the second jig 74, the third jig 76 is inserted into both notches 72a and 74d with the first notch 72a aligned with the second notch 74d. This restricts circumferential movement of the first jig 71 relative to the second jig 74. Therefore, the tip of first jig 71 can be inserted into second jig 74 with first notch 72a aligned with second notch 74d, which is held facing a predetermined direction. This allows strain gauge 41 to be attached to outer peripheral surface 31d of outer ring 31 with the orientation of strain gauge 41 held at the tip of first jig 71 accurately aligned.

[0076] After the strain gauges 41 are attached to the outer peripheral surface 31d of the outer ring 31, when the jig body 72 is removed from the second jig 74, the wiring 42 remains disposed radially inside the jig body 72. However, according to this embodiment, the jig body 72 can be easily separated from the wiring 42 by moving the jig body 72 so that the wiring 42 passes through the first cutout 72a.

[0077] Furthermore, after the strain gauges 41 are attached to the outer peripheral surface 31d of the outer ring 31, when the second jig 74 is removed from the insertion hole 21 together with the nut jig 75, the wiring 42 remains disposed radially inside the second jig 74. However, according to this embodiment, by aligning the second notch 74d with the third notch 75b, the second jig 74 and the nut jig 75 can be moved so that the wiring 42 passes through both notches 75b and 75d. This allows the second jig 74 and the nut jig 75 to be easily separated from the wiring 42.

[0078] Furthermore, after the strain gauge 41 is attached to the outer peripheral surface 31d of the outer ring 31, the outer opening 21g of the insertion hole 21 can be blocked with a blocking member 5, thereby preventing water flowing along the wiring 42 from entering the insertion hole 21.

[0079] [others] The embodiments disclosed above are illustrative in all respects and are not limiting. For example, the present invention can be applied to devices other than machine tools. Furthermore, the rolling bearing 3 can be applied to deep groove ball bearings and the like in addition to angular contact ball bearings. Furthermore, the mounting jig 70 may be composed of only the first jig 71. In this case, the first jig 71 holding the sensor 4 at its tip can be inserted directly into the insertion hole 21. Furthermore, the first jig 71 is not limited to the configuration of this embodiment as long as it is configured to hold the sensor 4 at its tip. [Explanation of symbols]

[0080] 1. Rolling bearing device with sensor 2. Housing 3. Rolling bearings 4 sensors 5. Closure element 21 Insertion hole 21e female thread 21g opening 22 Inner surface 31 outer ring 31d Outer surface 41a one side 41b Other side 42 Wiring 70 Mounting jig 71 First jig 72 Jig body 72a First notch 73 Elastic Members 73c End face (tip face) 74 Second jig 74b Protrusion 74c Inner peripheral surface (guide surface) 74d Second notch 75 Nut jig 75a female thread 75b Third notch 76 Third jig

Claims

1. A cylindrical housing; a rolling bearing having an outer ring whose outer peripheral surface is fitted to the inner peripheral surface of the housing; a sensor having wiring attached to the outer peripheral surface of the outer ring for detecting distortion of the outer ring, the method comprising: an assembly step of incorporating the rolling bearing into the housing by fitting an outer peripheral surface of the outer ring into an inner peripheral surface of the housing; a holding step of holding the sensor at a tip end of a first jig; and an attachment step of, after both the assembly step and the holding step, inserting the tip end of the first jig from the outer periphery of the housing into an insertion hole formed radially through the housing, and attaching the sensor to a position facing the insertion hole on the outer periphery of the outer ring.

2. a tip end portion of the first jig is made of an elastic member, In the holding step, one surface of the sensor is held on the tip surface of the elastic member, and an adhesive is applied to another surface of the sensor opposite to the one surface; 2. The method for assembling a sensor-equipped rolling bearing device according to claim 1, wherein in the mounting process, the elastic member inserted into the insertion hole presses the sensor held on its tip surface against the opposing position, thereby fixing the sensor to the opposing position with the adhesive.

3. A mounting jig for mounting a sensor having wiring on an outer peripheral surface of an outer ring of a rolling bearing in order to detect distortion of the outer ring with the outer peripheral surface of the outer ring fitted into an inner peripheral surface of a cylindrical housing, comprising: a first jig having a tip portion made of an elastic material; The elastic member is capable of holding the sensor on its tip surface, and while holding the sensor, can be inserted from the outer periphery of the housing into an insertion hole formed radially through the housing.

4. a cylindrical second jig having a male thread on its outer periphery that is fastened to the female thread formed in the insertion hole; the elastic member can be inserted into the second jig while holding the sensor, The mounting jig according to claim 3 , wherein an inner peripheral surface of the second jig is a guide surface that guides the insertion of the elastic member.

5. the first jig has a cylindrical jig body that can be inserted into the second jig, and the elastic member that is detachably attached to an axial tip portion of the jig body, The mounting jig according to claim 4 , wherein a first notch is formed in a part of the circumferential direction of the jig body over the entire axial length thereof for passing wiring of the sensor in the radial direction of the jig body.

6. The mounting jig according to claim 5, wherein a second notch is formed in a portion of the circumference of the second jig over the entire axial length thereof for passing the wiring of the sensor radially through the second jig.

7. the second jig has a protrusion that protrudes from the insertion hole when a portion of the male screw is fastened to the female screw of the insertion hole, a nut jig having a female thread that is fastened to the other part of the male thread on the outer periphery of the protrusion; The mounting jig of claim 6, further comprising a third jig that is inserted into the first notch and the second notch when the jig body is inserted into the second jig, thereby restricting circumferential movement of the jig body relative to the second jig.

8. The mounting jig according to claim 7, wherein a third notch is formed in a part of the circumferential direction of the nut jig over the entire axial length thereof for passing wiring of the sensor in the radial direction of the nut jig.

9. a cylindrical housing having an insertion hole formed therethrough in the radial direction; a rolling bearing having an outer ring whose outer peripheral surface is fitted to the inner peripheral surface of the housing; an elastic member inserted into the insertion hole; a sensor that is held by the elastic member at a position in the insertion hole closer to an inner periphery of the housing than the elastic member, and that has wiring; a closing member that closes an opening of the insertion hole on the outer circumferential side of the housing, the sensor has a surface attached to an outer peripheral surface of the outer ring at a position facing the insertion hole in order to detect distortion of the outer ring, The sensor is formed to a size that allows it to be inserted into the insertion hole from the outer periphery of the housing with the surface facing the opposing position.

Images