JP7296092B2 - Sensor Arrangement Structure and Sensor Arrangement Method - Google Patents

Description

The present invention relates to a sensor arranging structure and a sensor arranging method in which a linear detection body is arranged in a member provided with a housing space.

A linear detection body is known that consists of an inner conductor, a piezoelectric body provided in contact with the outer peripheral surface of the inner conductor, and an outer conductor provided in contact with the outer peripheral surface of the piezoelectric body (for example, , see Patent Document 1, etc.). In addition, it has been studied to form a linear detection body using a resistance wire made of conductive rubber or the like, a capacitor wire, an optical fiber, or the like. On the other hand, in recent years, by collecting and analyzing machine tool status information, it is possible to predict deterioration of consumable parts such as tools used in machine tools and machine tool failures in advance, and to make parts replacement more efficient. There is a need for a technique to formulate a maintenance plan for good implementation. In addition, collection and analysis of state information of devices such as robots, agricultural machinery, automobiles, and home appliances is being studied to predict failures and improve work efficiency. It is conceivable to use a sensor module having the above-described linear detection body as the state information detection device. Conventionally, acceleration sensors have been used for vibration measurement and the like. However, the natural frequency of the acceleration sensor matches part of the frequency of the vibration generated in the device, and since it resonates at that frequency, the sensitivity to vibration differs for each vibration frequency. . On the other hand, since the linear detection body has an extremely lower natural frequency than the frequency of the vibration generated in the device, the sensitivity when measuring the vibration of the device can be made almost constant regardless of the vibration frequency. Such effects are expected.

JP 2018-141668 A

However, when the present inventor actually fixed the linear detection body to a machine tool and measured the operating state and vibration state, it was found that the detection sensitivity was low and accurate state information could not be obtained. The reason for this is thought to be that when the linear detection body is fixed to the machine tool, the linear detection body and the machine tool vibrate together, making it difficult for the linear detection body to deform. .

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a sensor arrangement structure and a sensor arrangement method with improved detection sensitivity.

A sensor arrangement structure of the present invention for solving the above object is a sensor module having a linear detection body including an inner conductor, an outer conductor, and a piezoelectric body ;
a member provided with an accommodation space ;
a tension applying member that applies tension to the linear detection body within a range in which the linear detection body can be deformed ;
The sensor module has a held portion held by the member,
The linear detection body is arranged in the accommodation space so as to be deformable, and outputs a signal having an intensity corresponding to the deformation state.

According to the sensor arrangement structure of the present invention, since the linear detection body is arranged so as to be deformable in the accommodation space, when the member moves or vibrates (hereinafter referred to as vibration or the like), The linear detection body deforms in response to the vibration or the like. As a result, vibration or the like can be detected with high detection sensitivity.

The member may be a combination of multiple articles. Further, the accommodation space may be a space formed by a gap between articles that is generated when a plurality of articles are combined. The linear detection body may have a piezoelectric body held between an inner conductor and an outer conductor. Further, the linear detection body may be a piezoresistive wire whose electric resistance changes as it deforms, or may be a resistance wire made of conductive rubber or the like. The conductive rubber referred to here may be one whose electrical resistance changes depending on the magnitude of the applied pressure or the magnitude of the tensile force. Further, the linear detection body may be a capacitor wire whose thickness changes due to its deformation and whose capacitance changes. Alternatively, the linear detection body may be an optical signal output line using an optical fiber whose refractive index changes due to its deformation. That is, any linear detection object may be used as long as it outputs a signal having an intensity corresponding to its deformation state. Furthermore, the held portion may be a part of the linear detection body, or may be a part of the sensor module different from the linear detection body.

By applying tension to the linear detection body, the vibration of the member or the like is easily transmitted to the linear detection body. Therefore, the linear detection member is easily deformed in response to vibration or the like. In addition, by applying tension, the linear detection body is maintained in a predetermined shape in the initial state in which the member does not vibrate, etc., so that the reproducibility of the signal output from the linear detection body is improved. increases.

The tension applying member may be a weight attached to the linear detection body, or an elastic member held by the member or the sensor module.

Further, in the sensor arrangement structure of the present invention, the tension applying member may be a support wire that is twisted around the linear detection body to apply tension to the linear detection body.

By twisting the linear detection body with the support wire, not only can tension be applied to the linear detection body, but also the entire twisted stranded wire can be bent, so that vibration and the like can be detected with high sensitivity. Moreover, even if the accommodation space is a long and narrow space, the linear detection body can be easily installed in the accommodation space.

The support line may have higher rigidity than the linear detection body. The support line is preferably made of metal, and more preferably made of stainless steel.

Moreover, in the sensor arrangement structure of the present invention, the linear detection body may be spirally formed.

By making the linear detection body helical, the length of the linear detection body that can be accommodated in the accommodation space is increased and the linear detection body is easily deformed. Vibration or the like of the member can be detected.

Further, in the sensor arrangement structure of the present invention, the linear detection body may have a double-coil shape in which the axis of the helically wound spiral wire is further helically wound.

The length of the linear detection body that can be accommodated in the accommodation space is greatly increased, and the linear detection body is more easily deformed when the member is vibrated, thereby greatly increasing the detection sensitivity. be able to.

Further, in the sensor arrangement structure of the present invention, a support line may be arranged along the axis on the side of the axis of the spiral line.

By winding the straight linear detection body, which is a wire, around the support wire, the linear detection body can be easily formed into a double coil shape. The support line may be a spiral elastic member.

A method of arranging a sensor according to the present invention for solving the above object includes a sensor module having a linear detection body which includes an inner conductor, an outer conductor, and a piezoelectric body and which outputs a signal having an intensity corresponding to a deformation state, and the linear detection body. a preparation step of preparing a tension imparting member that imparts tension to the linear detection body within a deformable range, and a member having a housing space;
and an arranging step of causing the member to hold a part of the sensor module and arranging the linear detection body in the accommodation space so as to be deformable.

According to the sensor placement method of the present invention, when the member vibrates or the like, the linear detection member deforms in response to the vibration or the like within the housing space, so the vibration or the like of the member can be detected with high detection sensitivity. can do.

Further, in the sensor arrangement method of the present invention, the preparing step may be a step of preparing the sensor module having the linear detection body twisted with the support wire that is the tension applying member .

Since the entire twisted wire can bend, vibrations can be detected with high sensitivity, and the linear detection body can be installed in the accommodation space even if the accommodation space is a long and narrow space.

ADVANTAGE OF THE INVENTION According to this invention, the sensor arrangement|positioning structure and sensor arrangement|positioning method which improved the detection sensitivity can be provided.

It is a sectional view showing one embodiment of sensor arrangement structure of the present invention. FIG. 3 is a cross-sectional view schematically showing the structure of a linear detection body; 2(a) is a plan view of the screw body and the sensor substrate as seen from above in FIG. 1; FIG. 3(b) is a right side view of the screw body as seen from the right direction in FIG. 3(a). FIG. FIG. 2 is an exploded view before assembling the screw and the sensor module shown in FIG. 1; FIG. 10 is a flow chart showing a placement method for placing a sensor module on a screw; FIG. FIG. 2 is a cross-sectional view similar to FIG. 1, showing a first modification of the sensor arrangement shown in FIG. 1; FIG. 2 is a cross-sectional view similar to FIG. 1 showing a second modification of the sensor arrangement shown in FIG. 1; 2 is a cross-sectional view similar to FIG. 1 showing a third modification of the sensor arrangement shown in FIG. 1; FIG. 2 is a cross-sectional view similar to FIG. 1, showing a fourth modification of the sensor arrangement structure shown in FIG. 1; FIG. FIG. 10 is a cross-sectional view schematically showing a spindle and sensor modules corresponding to one embodiment of the sensor arrangement structure of the second embodiment; FIG. 11 is a cross-sectional view similar to FIG. 10 showing a modification of the sensor arrangement structure of the second embodiment; 11 is a cross-sectional view similar to FIG. 10 showing the sensor arrangement structure of the third embodiment; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the sensor arrangement structure of the present invention.

As shown in FIG. 1, the sensor arrangement structure of the present invention comprises screws 2 and sensor modules 3 and 41 . The screw 2 has a screw body 21 and a screw cap 22 . This screw 2 corresponds to an example of a member. The screw main body 21 is composed of a screw portion 211 formed on the front end side and a head portion 212 formed on the rear end side. The screw portion 211 and the head portion 212 are integrally formed. The screw portion 211 has a hollow cylindrical shape with a closed tip 211a. A screw thread is formed on the outer peripheral surface 211 b of the threaded portion 211 . Further, inside the screw portion 211, a first internal space SA defined by an inner peripheral surface 211c is formed.

The head 212 is formed in a hollow cylindrical shape with a larger diameter than the threaded portion 211 . A second internal space SB defined by an inner peripheral surface 212 a of the head 212 is formed inside the head 212 . The second internal space SB communicates with the first internal space SA. In the following description, when the first internal space SA and the second internal space SB are collectively referred to, they will be referred to as an accommodation space S. The rear end of the second internal space SB is open. A circumferential groove 212e (see FIG. 3B) is formed in the outer peripheral surface 212b of the head 212 over the entire circumference of the outer peripheral surface 212b. An O-ring 213 is fitted in the circumferential groove 212e as a waterproof means to prevent water or the like from entering through the gap between the head 212 and the screw cap 22. As shown in FIG.

The screw cap 22 is formed by integrally forming a cylindrical side wall portion 221 and a disk-shaped upper plate portion 222 . The screw lid 22 and the O-ring 213 may be omitted when the screw body 21 is installed in a place where there is no risk of water, chemicals, etc. reaching the sensor module 3. It is desirable to use it to When the screw cap 22 is attached to the screw body 21 , the rear end surface of the head 212 is covered with the upper plate portion 222 of the screw cap 22 . The screw lid 22 is fixed to the screw main body 21 by being press-fitted into the rear end portion of the head portion 212 with the O-ring 213 interposed therebetween. A female screw is formed on the inner peripheral surface of the side wall portion 221 of the screw cap 22, and a male screw is formed on the outer peripheral surface of the head portion 212 of the screw main body 21, so that the screw cap 22 and the screw main body 21 are screwed together. good too. By fastening with screws, it is possible to prevent the screw cap 22 from coming off from the screw main body 21 due to vibration or the like. A hole 222 a is formed in the center of the upper plate portion 222 . A grommet 23 is fixed to the hole 222a.

A sensor module 3 is arranged inside the screw 2 . This sensor module 3 is composed of a linear detection body 31 and a sensor substrate 32 . 1, a part of the sensor substrate 32 (lower right portion in FIG. 1) is cut away. The linear detection body 31 is a linear sensor having a piezoelectric body 312 (see FIG. 2), and generates a signal with an intensity corresponding to its deformation state. Specifically, a voltage corresponding to the length and deformation speed of the deformed portion of the linear detection body 31 is generated. However, it may generate a voltage corresponding to the length and amount of deformation of the deformed portion, or it may output a signal other than the voltage. The rear end of the linear detection body 31 is connected to the sensor substrate 32 by soldering. The configuration of the linear detection body 31 will be detailed later.

The linear detection body 31 is twisted with the support wire 41 . This support line 41 corresponds to an example of a tension applying member. The support wire 41 in this embodiment is formed by arranging seven stainless steel wires in a close-packed structure in its cross section and then twisting them together. The surface of the support wire 41 is covered with a resin such as nylon. With this coating, when the screw 2 vibrates, the surface of the linear detection body 31 is not rubbed by the hard stainless steel forming the support wire 41, so that the life of the linear detection body 31 can be extended. In addition, since the linear detection body 31 and the support line 41 are more likely to slide each other, the linear detection body 31 is more likely to be deformed. The diameter of the support wire 41 is 0.46 mm including the portion covered with resin. As the support wire 41, another metal wire such as a copper wire may be used, or a resin wire may be used. Furthermore, the support line 41 may be composed of a single line. Moreover, coating with resin when using a metal wire is not essential.

As will be described later, the linear detection body 31 is a flexible wire containing a metal wire inside. Further, since the support wire 41 also has flexibility, when the support wire 41 is twisted with the linear detection body 31, the linear detection body 31 and the support wire 41 tend to untwist. As a result, tension is applied to the linear detection body 31, and the linear detection body 31 can be prevented from being slackened. If the linear detection body 31 is slack, the slack part absorbs vibrations and the like, and the detection sensitivity of the linear detection body 31 is lowered. By preventing the slack, the linear detection body 31 can be easily deformed in response to vibration or the like. Further, since the shape of the linear detection body 31 in the initial state in which no vibration or the like occurs is maintained in a constant shape by the support line 41, the reproducibility of the signal output from the linear detection body 31 is enhanced. That is, when the same vibration or the like occurs in the screw 2, a signal with the same waveform is output. In addition, since the linear detection body 31 and the support wire 41 that are twisted together can be bent as a combined body of the two wires, the linear detection body 31 is likely to be deformed. Therefore, it is possible to output a signal with high sensitivity when vibration or the like occurs in the screw 2 . Furthermore, even if the first internal space SA is an elongated space, it can be easily inserted. Therefore, even if the screw 2 is elongated, the linear detection body 31 can be inserted and installed deep into the first internal space SA. can be done. If the rigidity of the support wire 41 is less than the rigidity of the linear detection body 31, the support wire 41 does not support the linear detection body 31 due to insufficient rigidity of the support line 41, and the linear detection body 31 becomes slack. may occur. Therefore, it is preferable to use the support line 41 having higher rigidity than the linear detection body 31 .

The rear end portion of the linear detection body 31 and the rear end portion of the support line 41 are fixed to the sensor substrate 32 with resin (not shown). If the rear end portion of the linear detection body 31 swings with respect to the sensor substrate 32, there is a possibility that the linear detection body 31 is disconnected at the mounting portion to the sensor substrate 32. can reduce the likelihood of Further, since the rear end portion of the linear detection body 31 and the rear end portion of the support line 41 are fixed, the attitude of the linear detection body 31 in the initial state becomes constant. reproducibility is enhanced. Although it is possible to apply tension to the linear detection body 31 by simply twisting the linear detection body 31 in a state in which the support wire 41 is not fixed, fixing the support wire 41 results in linear detection. It becomes possible to stabilize the posture of the body 31 in its initial state.

The sensor substrate 32 is fixed inside the screw 2 by being inserted into a notch groove 212c formed in the inner peripheral surface 212a of the head 212. As shown in FIG. A fixing structure for the sensor substrate 32 will be described later. The sensor substrate 32 has a sensor circuit 321 . Further, the sensor substrate 32 is formed with a front end side pattern wiring 322 and a rear end side pattern wiring 323 . This tip-side pattern wiring 322 corresponds to an example of a signal line. The linear detection body 31 is a portion having a detection function arranged on the tip side of the tip-side pattern wiring 322 . A signal (voltage) generated by deformation of the linear detection body 31 is input to the sensor circuit 321 through the tip-side pattern wiring 322 formed on the sensor substrate 32 . The sensor circuit 321 is a circuit having an operational amplifier. A signal processed by the sensor circuit 321 is sent to the wiring 9 via the rear end pattern wiring 323 and transmitted to an analysis device (not shown). The wiring 9 is covered with a protective tube 90 whose tip is fixed to the grommet 23 . An A/D converter and a wireless communication module may be provided on the sensor substrate 32, and signals processed by the sensor circuit 321 and the A/D converter may be wirelessly transmitted to the analysis device by the wireless communication module.

Next, the structure of the linear detection body 31 will be described. FIG. 2 is a cross-sectional view schematically showing the structure of the linear detection body.

As shown in FIG. 2, the linear detection body 31 has a piezoelectric sensor wire 310 and a sheath 314 covering its outer circumference. The piezoelectric sensor wire 310 is composed of an inner conductor 311 , a piezoelectric body 312 and an outer conductor 313 . The internal conductor 311 is arranged at the center of the piezoelectric sensor wire 310 and is composed of seven conductor wires 3110 . The piezoelectric body 312 is provided on the outer circumference of the internal conductor 311 . The external conductor 313 is provided on the outer periphery of the piezoelectric body 312 .

The seven conductor wires 3110 all have a diameter of 10 μm, of which four are stainless steel conductor wires 3110S and the remaining three are copper conductor wires 3110C. In FIG. 2, the stainless steel conductor wire 3110S is indicated by left-down hatching, and the copper conductor wire 3110C is indicated by right-down hatching. In the inner conductor 311 shown in FIG. 2, a stainless steel conductor wire 3110S (stainless steel wire) is used as the conductor wire arranged in the center, and a stainless steel conductor wire 3110S (stainless steel wire) is used as the conductor wire arranged in the outer periphery. 3110S and copper conductor lines 3110C are used alternately. The conductor wire 3110C made of copper has a lower electrical resistance and is softer than the conductor wire 3110S made of stainless steel. Conversely, the stainless steel conductor wire 3110S has higher electrical resistance than the copper conductor wire 3110C, but higher mechanical strength (for example, tensile strength) and rigidity.

The seven conductor wires 3110 are arranged at each vertex of the regular hexagon and at the center of the regular hexagon. These seven conductor wires 3110 are in a state of being twisted together. That is, the internal conductor 311 is obtained by arranging seven conductor wires 3110 in a close-packed structure in its cross section and then twisting them together. The maximum thickness of the internal conductor 311 in this case is 30 μm. By twisting the plurality of conductor wires 3110 loosely or in a medium twist, looseness in the direction opposite to the twist direction is allowed, and this looseness causes the piezoelectric sensor wire 310 and thus the linear detection. The body 31 can be made flexible.

The diameter of the conductor wire 3110 is not limited to 10 μm, and may be 8 μm or more and 40 μm or less, preferably 8 μm or more and 30 μm or less. The thinner the conductor wire 3110, the higher the flexibility but the lower the strength and rigidity, and the thicker the conductor wire 3110, the lower the flexibility but the higher the strength and rigidity. Moreover, if the thickness of the conductor wire 3110 is 20 μm or more, it can be manufactured at low cost and is easy to manufacture. Moreover, the configuration is not limited to the configuration in which the conductor wires 3110 have the same thickness, and the inner conductor 311 may be configured by twisting the conductor wires 3110 having different thicknesses.

In addition, although the inner conductor 311 shown in FIG. 2 is formed by twisting seven conductor wires 3110, the number may not be seven. By twisting the plurality of conductor wires 3110 together, the flexibility of the piezoelectric sensor wire 310 and thus the linear detection body 31 can be enhanced. Alternatively, for example, a plurality of twisted bundles may be prepared and twisted in a plurality of stages, such as further twisting these bundles. For example, a configuration may be adopted in which seven bundles are prepared by twisting seven thin conductor wires 3110 and the bundles are further twisted. By twisting the fibers in multiple stages, the flexibility of the linear detection body 31 is further increased, so that the linear detection body 31 is easily deformed in response to vibration or the like. As a result, the detection sensitivity of the linear detector 31 can be enhanced. When the twisting process is performed a plurality of times, as in the case of twisting in a plurality of stages, the directions of twisting may be varied. On the other hand, a plurality of conductor wires 3110 may be linearly bundled without being twisted together. Alternatively, these configurations may be combined, for example, by twisting a bundle of a plurality of conductor wires 3110 that are not twisted together and a plurality of twisted conductor wires 3110 . Even in these cases, by applying a piezoelectric material, a plurality of conductor wires 3110 can be bonded and bundled together to produce a single piezoelectric fiber.

In the piezoelectric sensor wire 310 described above, a plurality of types of conductor wires with different mechanical strength and electrical resistance are used as the conductor wire 3110 forming the inner conductor 311. , the central conductor wire 3110 may be replaced with a copper conductor wire 3110C, or all seven conductor wires 3110 may be copper conductor wires 3110C. Conversely, if the mechanical strength and rigidity are to be further increased, all of the seven conductor wires 3110 may be made of stainless steel conductor wires 3110S. Further, instead of the stainless steel conductor wire 3110S, a conductor wire made of tungsten, a conductor wire made of a high-tensile steel material such as tungsten and its alloy, or a conductor wire made of ultra-high-strength steel may be used. Alternatively, a conductor wire made of titanium, or a conductor wire made of titanium alloy, magnesium, magnesium alloy, or the like may be used. Further, it may be a conductor wire containing carbon nanotubes or a conductor wire containing pitch-based carbon fiber. Alternatively, a conductor wire made of a spring steel material that easily deforms elastically may be used.

The piezoelectric body 312 is formed by coating the inner conductor 311 with a piezoelectric material such as polyvinylidene fluoride (PVDF). Polyvinylidene fluoride is a lightweight polymeric material that produces a piezoelectric effect, and has the characteristic of generating voltage when pressure is applied to it, and generating strain when voltage is applied. The piezoelectric body 312 is subjected to polarization treatment, and a voltage is induced between the inner conductor 311 and the outer conductor 313 when the piezoelectric body 312 is deformed. When the screw 2 shown in FIG. 1 is placed on a moving object such as a machine tool or a robot or a structure such as a building, when external force such as an earthquake is applied to the structure or vibrations of the moving object caused by the operation, The generated vibration or the like is transmitted to the screw 2 . A voltage is induced between the inner conductor 311 and the outer conductor 313 by the deformation of the piezoelectric body 312 due to the vibration or the like transmitted to the screw 2 .

Besides polyvinylidene fluoride, the piezoelectric material constituting the piezoelectric body 312 shown in FIG. 2 includes trifluoroethylene (TrEF), a mixed crystal material of PVDF and TrEF, and bipolar materials such as polylactic acid, polyuric acid, and polyamino acid. A polymer material with a child moment can be mentioned. The method of applying the piezoelectric material may be dip coating, spray coating using a spray or the like, brush coating, or coating using a coating device such as a coater. may be It should be noted that the configuration is not limited to the application, and for example, a configuration in which a strip-shaped PVDF film is spirally wound around the internal conductor 311 may be used.

The thickness of piezoelectric body 312 is preferably equal to or greater than the diameter of conductor wire 3110 . Although the thickness of the piezoelectric body 312 shown in FIG. 2 is 10 μm at the thinnest point, it may be 10 μm or more and 50 μm or less. The thicker the piezoelectric body 312, the better the detection sensitivity. However, the limit value of the thickness of the piezoelectric body 312 is determined by the viscosity of the applied piezoelectric material and the coating method. In addition, if the thickness of the piezoelectric body 312 is too thick, the piezoelectric sensor wire 310 and thus the linear detection body 31 become too hard and lack flexibility.

In the inner conductor 311 shown in FIG. 2, since a plurality of conductor wires 3110 are twisted together, there are depressions at the boundaries between the conductor wires 3110 . This hollow portion can hold a larger amount of piezoelectric material, and the volume of the piezoelectric material is larger (thicker), resulting in better detection sensitivity than other portions. The inner conductor 311 has six portions where the piezoelectric material is thicker than other portions due to these dents, which are evenly spaced in the circumferential direction. be a factor.

Although the adjacent conductor wires 3110 shown in FIG. 2 are almost in contact with each other, the piezoelectric material permeates through a slight gap due to capillary action, and the gap between the adjacent conductor wires 3110 (the inside of the inner conductor 311) is filled with the piezoelectric material. is filled with However, depending on the viscosity of the piezoelectric material and the application method, the piezoelectric material may not permeate into the gaps between the adjacent conductor wires 3110 , but the piezoelectric material is held at least in the portion facing the outer periphery of the inner conductor 311 . It is good if it is. In addition, in the configuration using the strip-shaped PVDF film as the piezoelectric body 312 described above, the linear detection body 31 is obtained in which the piezoelectric material does not permeate the gaps between the adjacent conductor wires 3110 . In this linear detection body 31, the flexibility of the linear detection body 31 is increased compared to the one in which the piezoelectric material permeates the gaps between the adjacent conductor wires 3110, so the detection sensitivity of the linear detection body 31 is increased. increase.

The external conductor 313 shown in FIG. 2 is a layer formed by coating the outer periphery of the piezoelectric body 312 with a polymer conductive material containing carbon such as carbon nanotubes. As the conductive material forming the external conductor 313, a polymer conductive material containing fine particles of silver, a silver paste, or the like may be used. The method of applying the conductive material may be dip coating, spray coating using a spray or the like, brush coating, or a coating device using a coater or the like. may be applied by The thickness of the outer conductor 313 is preferably equal to or less than the diameter of the conductor wire 3110 and is also preferably equal to or less than the thickness of the piezoelectric body 312 . Although the thickness of the outer conductor 313 shown in FIG. 2 is 5 μm, it may be 5 μm or more and 50 μm or less. Alternatively, a conductive wire may be used for the outer conductor 313 instead of using a conductive material.

A sheath 314 covers the outer circumference of the piezoelectric sensor wire 310 in order to improve wear resistance, chemical resistance, and rust resistance. This sheath 314 has a two-layer structure consisting of an inner layer 3141 and an outer layer 3142 each having a thickness of 6 μm. The inner layer 3141 is made of softer material than the outer layer 3142 . The inner layer 3141 is formed by applying polyamide synthetic resin, but may be formed by applying polyvinyl chloride resin. The outer layer 3142 is made of a material with higher wear resistance than the inner layer 3141 . This outer layer 3142 is formed by applying polytetrafluoroethylene (PTFE). However, it is formed by applying tetrafluoride/hexafluoropropylene fluororesin (FEP), tetrafluoroethylene ethylene copolymer (EPFE), or tetrafluoroethylene perfluoroalkoxyethylene copolymer fluororesin (PFA). may The coating referred to herein may be dip coating, spray coating, brush coating, or coating using a coating device such as a coater. In addition, it is preferable to apply a plurality of times in consideration of the occurrence of pinholes. Also, the outer layer 3142 may be thicker than the inner layer 3141 . Furthermore, the inner layer 3141 may be made of a combustible material, but the outer layer 3142 is preferably made of a flame-retardant material, a non-combustible material, or a flame-resistant material. Also, the thickness of the entire sheath 314 is preferably 5 μm or more and 50 μm or less. Furthermore, the sheath 314 may be constructed using a polyester tape type or a tube type (either single layer or multiple layers). When these types are used, the thickness of the sheath 314 may be 20 μm or more and 50 μm or less. A shield wire may be arranged outside the sheath 314, and a second sheath may be arranged further outside thereof.

Since the maximum thickness of the piezoelectric sensor wire 310 shown in FIG. 2 (total thickness of the inner conductor 311, the piezoelectric body 312, and the outer conductor 313) is 60 μm, a double structure sheath 314 having a thickness of 10 μm is provided. Even in this case, the linear detection body 31 has a thickness of 0.1 mm or less. Here, as an example of the linear detection body 31 that can be easily manufactured and obtained at a low cost, an inner conductor 311 with a thickness of 60 μm using a conductor wire 3110 with a diameter of 20 μm and a piezoelectric body with a maximum thickness of 20 μm 312 and an outer conductor 313 having a thickness of 10 μm are formed. In this configuration, the thickness to the outer conductor 313 is 0.12 mm. Even if a sheath 314 having a double structure is provided, a piezoelectric sensor wire 310 of 0.16 mm or less can be realized. In addition, the sheath 314 may be composed of a single layer. When configured with a single layer, the sheath 314 may be configured using materials such as PVC (polyvinyl chloride), PE (polyethylene), etc., in addition to the materials exemplified as the materials configuring the outer layer 3142 described above.

FIG. 3(a) is a plan view of the screw body and the sensor substrate viewed from above in FIG.

As described above, the second internal space SB is formed inside the head portion 212 of the screw body 21 . As shown in FIG. 3( a ), a pair of notch grooves 212 c are arranged on an inner peripheral surface 212 a of the head 212 so as to face each other and are formed in a U shape and an inverted U shape in plan view. is formed. The depth of the notch groove 212 c is substantially the same as the height of the sensor substrate 32 . Both ends 32a of the sensor substrate 32 in the width direction (horizontal direction in FIG. 3A) are fitted into the cutout grooves 212c. The sensor module 3 (see FIG. 1) is held by the screw body 21 by fitting the sensor substrate 32 into the notch groove 212c. That is, the both end portions 32a correspond to an example of a held portion. In FIG. 3A, a gap in the thickness direction of the sensor substrate 32 is shown between the sensor substrate 32 and the notch groove 212c so that the shape of the notch groove 212c can be understood. A gap in the thickness direction of the sensor substrate 32 does not exist. That is, the sensor substrate 32 is press-fitted into the pair of notch grooves 212c. Therefore, when the sensor board 32 is inserted into the screw body 21, the sensor board 32 is fixed in that state. Although the sensor substrate 32 is sandwiched and held in the thickness direction in this embodiment, the sensor substrate 32 may be sandwiched and held in the width direction. Furthermore, the sensor substrate 32 may be held so as to be sandwiched between the screw body 21 and the screw cap 22 (see FIG. 1). When the sensor substrate 32 is sandwiched between the screw body 21 and the screw lid 22, the upper and lower ends of the sensor substrate 32 correspond to an example of the held portion.

FIG.3(b) is the right side view which looked at the screw main body from the right direction in Fig.3 (a).

As shown in FIG. 3B, a pair of flat portions 212d are formed on the lower portion of the outer peripheral surface 212b of the head portion 212. As shown in FIG. The pair of plane portions 212d are portions where a tool such as a spanner or wrench for rotating the screw 2 engages when the screw 2 shown in FIG. 1 is attached to a device such as a machine tool or a structure such as a building. . If a portion that engages with a tool is formed in the screw cap 22, even if a rotational force is applied to the screw cap 22 with a tool, a slip occurs between the O-ring 213 fitted in the screw body 21 and the screw cap 22, resulting in a screw failure. There is a possibility that the main body 21 will not rotate. As in this embodiment, by forming a portion that engages with a tool in the screw body 21 , the rotational force applied by the tool can be directly transmitted to the screw portion 211 .

FIG. 4 is an exploded view of the screw and sensor module shown in FIG. 1 before assembly. Also, FIG. 5 is a flow chart showing an arrangement method for arranging the sensor module on the screw.

As shown in FIGS. 4 and 5, first, the screw body 21 having the accommodation space S, the sensor module 3, the O-ring 213, and the screw cap 22 are prepared (step S1). In the sensor module 3 prepared in this embodiment, the support wires 41 and the wires 9 that are pre-twisted around the linear detection body 31 are fixed to the sensor substrate 32 . However, the support line 41 and wiring 9 may be prepared separately from the sensor module 3 . If they are separately prepared, a fixing step for fixing them to the sensor module 3 may be provided. Moreover, when the sensor module 3 and the support line are prepared separately, a twisting process for twisting them may be provided.

Next, the sensor module 3 to which the support line 41 and the wiring 9 are fixed is brought into contact with the bottom of the notch groove 212c of the head 212 with the tip of the linear detection body 31 (lower end in FIG. 4) leading the sensor board 32. up to the housing space S (step S2). Thereby, most of the linear detection body 31 and the support line 41 are arranged in the first internal space SA. Further, the sensor substrate 32 is arranged in the second internal space SB and is held by the screw main body 21 by being sandwiched between the notch grooves 212c. By holding the sensor substrate 32, the linear detection body 31 is arranged at a predetermined position and in a predetermined shape. As shown in FIG. 1, in this embodiment, the linear detection body 31 and the support line 41 are spaced apart from the inner peripheral surface 211c of the screw portion 211. Both may be in contact with the inner peripheral surface 211c. Also, one or both of the linear detection body 31 and the support line 41 are formed longer than those shown in FIG. It may be configured so as to be in contact with the bottom of the surface 211c.

After that, the O-ring 213 is fitted into the circumferential groove 212e, and the screw lid 22 is put on the head 212 (step S3). These steps result in a screw 2 with a sensor module 3 arranged therein. Note that the O-ring 213 may be fitted into the circumferential groove 212e before inserting the sensor module 3 into the housing space S in step S2 described above.

According to the embodiment described above, the linear detection body 31 is arranged in the accommodation space S so as to be deformable in a state in which tension is applied by being twisted with the support wire 41, so that the vibration of the screw 2 or the like is prevented. It is easy to deform according to. Therefore, vibration or the like can be detected with high detection sensitivity. Further, since the linear detection body 31 in the initial state is maintained in a predetermined shape, the reproducibility of the signal output from the linear detection body 31 is enhanced.

Next, a modified example of this embodiment will be described. In the following description, the same reference numerals as those used so far may be assigned to the names of constituent elements that are the same as the names of the constituent elements that have been explained so far, and duplicate explanations will be omitted.

FIG. 6 is a cross-sectional view similar to FIG. 1, showing a first modification of the sensor arrangement shown in FIG.

This first modification differs from the example shown in FIG. 1 in that the support line 41 is not provided and instead a weight 42 is provided. This first modification is an example suitable for installing the screw 2 so that the tip 211a of the screw 2 faces downward. In addition, in the screw 2 of the first modified example, when it is expected that the tip 211 a of the screw 2 is directed other than downward, the tip of the linear detection body 31 is placed on the inner circumference of the screw portion 211 . Preferably, it is fixed to the bottom of surface 211c. As shown in FIG. 6, the weight 42 is made of lead and has a spherical shape with a through hole 42a in the center. The material of the weight 42 is not limited to lead, and may be other metal such as brass or copper, or resin. Also, the shape may be other than spherical. This weight 42 corresponds to an example of a tension imparting member. The linear detection body 31 passes through the through hole 42a and is connected to the weight 42 by tying a knot 31c to the tip of the passed through hole 42a. As a result, the weight 42 is movable relative to the linear detection body 31 in the extending direction of the linear detection body 31 and immovable relative to the linear detection body 31 in other directions. 31 is attached. However, the linear detection body 31 and the weight 42 may be fixed with an adhesive or the like so that the weight 42 and the linear detection body 31 cannot move relative to each other in all directions. By providing the weight 42, it is possible to apply an appropriate tension to the linear detection body 31 and keep the initial state constant. Furthermore, since the weight 42 increases the inertial mass of the tip portion of the linear detection body 31, deformation of the linear detection body 31 increases when the screw 2 vibrates. As a result, the movement of the member can be detected with high detection sensitivity. The weight of the weight 42 can be appropriately set according to the rigidity of the linear detection body 31 and the expected amplitude of vibration or the like. An adhesive or the like may be applied to the knot 43c so that the knot 43c is not untied. Further, instead of the weight 42 with the through hole 42a, a weight 42 with a ring may be used to tie the linear detection object 31 to the ring, and a weight 42 with a crack may be used to connect the linear detection object 31 to the ring. The linear detection member 31 may be sandwiched between the weights 42 by plastically deforming the weights 42 after inserting the weights 31 into the cracks.

FIG. 7 is a cross-sectional view similar to FIG. 1, showing a second modification of the sensor arrangement shown in FIG.

This second modification differs from the example shown in FIG. 1 in that the support wire 41 is not provided and instead a helical spring 43 is provided. This helical spring 43 corresponds to an example of an elastic member. As shown in FIG. 7, the helical spring 43 is fixed to the sensor substrate 32 at the spring rear end 43b. A spring tip 43a of the helical spring 43 is a movable free end. The spring tip 43a is formed with a protrusion (not shown) that protrudes in the axial direction and has a ring at the protruding end for allowing the linear detection body 31 to pass therethrough. With the helical spring 43 slightly compressed, the tip of the linear detector 31 is wrapped around the ring of the projecting portion, and the ring is crushed and plastically deformed, thereby fixing the tip of the linear detector 31 to the spring tip 43a. ing. As a result, tension is applied to the linear detection body 31 by the springiness of the helical spring 43 . In this second modification, when the screw 2 vibrates or the like, the spring tip 43a of the helical spring 43 swings, so that the vibration of the screw 2 or the like can be detected. The spring constant of the helical spring 43 can be appropriately set according to the rigidity of the linear detection body 31 and the expected amplitude of vibration. In the second modified example, the linear detection body 31 is fixed to the helical spring 43 so as to form a straight line. The linear detection body 31 may be arranged in such a shape as to be bent at the central portion. Alternatively, the linear detection member 31 may be arranged in a zigzag manner by winding it around a helical spring at a plurality of locations between the spring tip 43a and the spring rear end 43b.

FIG. 8 is a cross-sectional view similar to FIG. 1, showing a third modification of the sensor arrangement structure shown in FIG.

This third modification differs from the example shown in FIG. 1 in that the support line 41 is not provided and the linear detection body 31 is spirally formed. As shown in FIG. 8, the linear detection body 31 is spirally arranged in the first internal space SA so that the tip thereof contacts the bottom of the inner peripheral surface 211c of the threaded portion 211. As shown in FIG. Note that the tip of the linear detection body 31 may be arranged so as to be separated from the bottom of the inner peripheral surface 211c. By making the linear detection body 31 helical, the length of the linear detection body 31 that can be accommodated in the first internal space SA is increased and the linear detection body 31 is easily deformed, resulting in high detection sensitivity. Vibration or the like of the member can be detected by . Further, the outermost portion of the spiral of the linear detection body 31 is in contact with the inner peripheral surface 211c that defines the first internal space SA. By bringing the linear detection body 31 into contact with the inner peripheral surface 211c, the vibration of the screw 2 or the like can be directly transmitted to the linear detection body 31, so that the detection sensitivity can be further improved. However, the linear detection body 31 and the inner peripheral surface 211c may be separated from each other.

In this third modification, after twisting the seven conductor wires 3110 shown in FIG. is stabilized, the materials of the piezoelectric body 312, the outer conductor 313, and the sheath 314 are applied to obtain the spiral linear detection body 31. FIG. In the third modification, it is desirable to use spring steel for all or part of the seven conductor wires 3110 shown in FIG. 2 in order to maintain the helical shape for a long period of time. When spring steel is not used, it is desirable to use a highly rigid conductor wire 3110, such as a conductor wire 3110S having a thickness of 20 μm made entirely of stainless steel. In addition, in the third modification, the linear detection body 31 is formed in a helical shape when the linear detection body 31 is produced. I don't mind. In other words, a molding step may be provided for molding the straight linear detection body 31 into a spiral shape. However, considering damage to the piezoelectric body 312 during molding, it is desirable to shape the piezoelectric body 312 before it is applied. Alternatively, a rod having a spiral groove may be prepared, the straight linear detection body 31 may be wound along the spiral groove, and the linear detection body 31 may be inserted into the first internal space SA together with the rod. . In that case, it is desirable that the groove width and the groove depth of the spiral groove be larger than the diameter of the linear detection body 31 so that the linear detection body 31 can be deformed within the spiral groove.

FIG. 9 is a cross-sectional view similar to FIG. 1, showing a fourth modification of the sensor arrangement structure shown in FIG.

In this fourth modified example, the support line 41 is not provided, and instead the support line 45 is arranged. This is different from the example shown in FIG. As shown in FIG. 9, the support wire 45 is a helical spring formed by spirally forming a spring steel having a diameter of 0.5 mm including the coating and having a surface coated with a resin such as nylon having a thickness of 0.05 mm. . By providing the coating, when the screw 2 vibrates or the like, the surface of the linear detection body 31 is not rubbed by the spring steel forming the support wire 45, so the life of the linear detection body 31 can be extended. This support line 45 corresponds to an example of a spiral elastic member. The tip of the support wire 45 is in contact with the bottom of the inner peripheral surface 211c of the threaded portion 211 . However, the tip of the support wire 45 may be arranged so as to be separated from the bottom of the inner peripheral surface 211c. A rear end portion of the support line 45 is formed in a straight line, and the rear end is fixed to the sensor substrate 32 . The outer diameter of the spiral of the support wire 45 is set to be twice the wire diameter of the linear detection body 31 smaller than the diameter of the inner peripheral surface 211c defining the first internal space SA. As a result, the outermost spiral of the linear detection body 31 is in contact with the inner peripheral surface 211 c of the screw body 21 . By bringing the linear detection body 31 into contact with the inner peripheral surface 211 c , the vibration of the screw 2 and the like can be directly transmitted to the linear detection body 31 . However, the linear detection body 31 and the inner peripheral surface 221c may be separated from each other.

The linear detection body 31 draws a small spiral around the support line 45 . Hereinafter, this small spiral line is referred to as a spiral line. Since the spiral wire draws a large spiral along the shape of the support wire 45, the linear detection body 31 as a whole has a double coil shape. That is, in this fourth modification, the linear detection body 31 has a double coil shape in which the axis of the spiral wire is further helically wound. The tip of the linear detection body 31 is held by being sandwiched between the ends of the support wire 45 . Note that the tip of the linear detection body 31 may be fixed to the support line with an adhesive or a metal fitting.

Although the support line 45 is provided in this embodiment, the linear detection body 31 alone may be molded so as to maintain the double-coil shape without providing the support line 45 . However, it is preferable to provide the support line 45 because it takes time and effort to form the double-coiled shape so that it can be maintained. By providing the support wire 45 , the double-coil-shaped linear detection body 31 can be easily obtained by simply winding the straight linear detection body 31 , which is a wire, around the support wire 45 . Further, although an example in which the support wire 45 is made of spring steel has been shown, the support wire 45 may be made of other metal such as stainless steel or resin. Since the linear detection body 31 is double-coiled in the fourth modification, the length of the linear detection body 31 that can be accommodated in the first internal space SA can be greatly increased. In addition, since the linear detection body 31 is easily deformed, it becomes possible to detect the vibration of the screw 2 with higher detection sensitivity. Furthermore, by using a helical spring for the support wire 45, the helical spring deforms together with the linear detection member 31 due to its springiness when the screw 2 vibrates, so that detection sensitivity can be enhanced.

Next, the sensor arrangement structure of the second embodiment will be described. In the subsequent description, components having the same names as those of the components described so far will be described with reference numerals used so far, and overlapping descriptions may be omitted.

FIG. 10 is a cross-sectional view schematically showing a spindle and a sensor module corresponding to one embodiment of the sensor arrangement structure of the second embodiment. Incidentally, in FIG. 10, hatching of the chuck 54, the leading end side bearing 55, and the trailing end side bearing 56 is omitted in order to make the drawing easier to see.

The sensor arrangement structure of the second embodiment differs from the previous embodiment in that the sensor module 3 is arranged on the spindle 5 of the machining center. As shown in FIG. 10 , the main shaft 5 has an outer cylinder 51 , a rotating body 52 , an inner cylinder 53 , a chuck 54 , a front bearing 55 , a rear bearing 56 and a rotary bush 57 . This main shaft 5 corresponds to an example of a member. The outer cylinder 51 is cylindrical and fixed to a headstock (not shown). This outer cylinder 51 moves together with the headstock to a position programmed by NC control. The inner cylinder 53 is composed of a cylindrical portion 531 and a fixed portion 532 . The cylindrical portion 531 and the fixed portion 532 are integrally formed. By fixing the fixing portion 532 to the outer cylinder 51 , the cylindrical portion 531 is arranged inside the outer cylinder 51 so as to be coaxial with the outer cylinder 51 .

A front-end bearing 55 and a rear-end bearing 56 are press-fitted into the inner peripheral surface 51 a of the outer cylinder 51 . The rotating body 52 is rotatably supported by the outer cylinder 51 by these front end bearings 55 and rear end bearings 56 . The rotor 52 has a cylindrical shape with a space inside, and a gear 521 is formed at the rear end portion. A pinion fixed to a motor (not shown) meshes with the gear 521 . As the motor rotates, the rotating body 52 also rotates. A chuck 54 is provided on the tip side of the rotating body 52 . The chuck 54 has a leading end portion 541 and a trailing end portion 542 . A tip end portion 541 of the chuck 54 holds a tool 58 such as a drill or an end mill. A rear end portion 542 of the chuck 54 is detachably gripped by the rotating body 52 by a gripping mechanism (not shown). As rotating body 52 rotates, chuck 54 and tool 58 rotate with rotating body 52 .

A rotary bush 57 is arranged between the cylindrical portion 531 of the inner cylinder 53 and the rotating body 52 . This rotary bushing 57 has a retainer 571 and a plurality of balls 572 . The ball 572 is in contact with the inner peripheral surface 52a of the rotating body 52 and the outer peripheral surface 531a of the cylindrical portion 531, respectively. When the rotating body 52 rotates, the ball 572 also rotates. The rotor 52 and the rotary bush 57 are restricted from moving relative to the outer cylinder 51 in the axial direction by restrictors (not shown).

Inside the cylindrical portion 531, a third internal space SC defined by an inner peripheral surface 531b of the cylindrical portion 531 is formed. This third internal space SC corresponds to an example of an accommodation space. The sensor module 3 is composed of a helically shaped linear detection body 31 and a linear signal line 33 . The linear detection body 31 is arranged inside the third internal space SC. The signal line 33 has a front end portion disposed within the third internal space SC and a rear end portion extending outside the third internal space SC.

The linear detection body 31 is arranged on the tip side of the signal line 33 . This linear detection body 31 is spirally formed in the same manner as the linear detection body 31 shown in FIG. The outer diameter of the spiral of the linear detection body 31 is the same as the diameter of the inner peripheral surface 531 b of the cylindrical portion 531 . Therefore, the outermost spiral of the linear detection body 31 is in contact with the inner peripheral surface 531 b of the cylindrical portion 531 . The outer diameter of the spiral of the linear detection body 31 may be slightly larger than the diameter of the inner peripheral surface 531b, or may be smaller than the diameter of the inner peripheral surface 531b. The linear detection body 31 is prevented from moving to the front end side by contacting the rear end portion 542 of the chuck 54 at the front end. The linear detection body 31 is prevented from moving toward the rear end by a retaining ring 5311 fixed to the cylindrical portion 531 . In the present embodiment, the rear end portion of the linear detection body 31 in contact with the retaining ring 5311 corresponds to an example of the held portion. The linear detection body 31 is sandwiched between the rear end portion 542 of the chuck 54 and the snap ring 5311 while being somewhat compressed in the axial direction. Therefore, the tip portion of the linear detection body 31 is pressed against the rear end side portion 542 of the chuck 54 due to the elasticity of the linear detection body 31 itself.

As the tool 58 deteriorates, vibrations and the like generated in the tool 58 and the chuck 54 holding the tool 58 during machining increase. In the second embodiment, since the vibration or the like generated in the chuck 54 is directly applied to the linear detection body 31, the linear detection body 31 is deformed and outputs a signal having an intensity corresponding to the vibration or the like. By analyzing this signal, the state of deterioration of the tool 58 can be diagnosed. In addition, even when the tool 58 suitable for the workpiece is not used, the vibration and the like generated in the chuck 54 are increased. Since the linear detector 31 outputs a signal corresponding to this vibration or the like, it is possible to determine whether or not an inappropriate tool 58 is being used by analyzing the signal. Furthermore, when the tip end side bearing 55 or the rear end side bearing 56 wears out, the vibration and the like when the rotating body 52 is rotated increases. Vibration or the like generated in the rotating body 52 is transmitted to the inner cylinder 53 via the rotary bushing 57 and transmitted to the linear detection body 31 in contact with the inner cylinder 53, and the linear detection body 31 is deformed to cause vibration or the like. Outputs a signal with a strength corresponding to Among the signals output by the linear detection body 31, the signal of the frequency according to the number of revolutions generated in the ball 552 provided on the front end side bearing 55 and the ball 562 provided on the rear end side bearing 56 is analyzed. , it is also possible to diagnose the state of deterioration of the leading end side bearing 55 and the trailing end side bearing 56 .

The signal line 33 has the same structure as the linear detection body 31 except that an insulator is used between the inner conductor 311 and the outer conductor 313 instead of the piezoelectric body 312 shown in FIG. . This insulator consists of a polyethylene terephthalate (PET) film. However, a PVC film or the same material as the inner layer 3141 or the outer layer 3142 of the sheath 314 may be used. In other words, other materials may be used as long as they are insulating materials. As the insulator, the piezoelectric body 312 may be heated to remove the piezoelectric function. This signal line 33 is for sending the signal output by the linear detection body 31 .

As shown in FIG. 10, the third internal space SC inside the cylindrical portion 531 is provided with an oil pipe 59 for supplying lubricating oil. The signal line 33 is laid through the inside of the oil pipe 59 to just before the linear detection member 31 . By passing through the inside of the oil pipe 59, it is possible to prevent the signal line 33 from coming into contact with the operating portion and being disconnected. However, a pipe other than the oil pipe 59 may be provided and passed through the pipe, or the signal line 33 may be laid along the inner peripheral surface 531b of the cylindrical portion 531 . The rear end of the signal line 33 is connected to the control device 8 of the machining center. This control device 8 has a vibration analysis function. The transmitted signal is analyzed by the controller 8 . Based on the analysis results, the display unit of the machining center displays information indicating whether or not an inappropriate tool 58 is being used, parts replacement timing, maintenance required timing, failure prediction, and the like. A wireless communication module may be provided in the control device 8 to wirelessly transmit the signal output by the linear detection member 31 or the analysis result to a parts manufacturer, a maintenance manufacturer, a machining center manufacturer, or the like.

According to the second embodiment, since the linear detection body 31 is arranged on the main shaft 5, in addition to the vibration of the frequency corresponding to the number of revolutions of the rotating body 52, the sphere 552 of the leading end bearing 55 and the trailing end bearing It is also possible to obtain vibration of a frequency corresponding to the rotation of the balls 562 of the rotary bushing 56 and the balls 572 of the rotary bushing 57 . By analyzing the changes in vibration at these frequencies, it is possible to grasp whether or not the tool 58 is used properly and the life of the tool 58, as well as the state of deterioration of the tip side bearing 55, the rear side bearing 56, and the rotary bush 57. can.

11 is a cross-sectional view similar to FIG. 10, showing a modification of the sensor arrangement structure shown in FIG. Also in FIG. 11, the hatching of the chuck 54, the leading end side bearing 55, and the trailing end side bearing 56 is omitted in order to make the drawing easier to see.

This modification differs from that shown in FIG. 10 in the structure of the chuck 54 and the structure for holding the linear detection body 31 . The chuck 54 is composed only of a front end portion 541 and is integrated with the rotating body 52 on the rear end side. In this modification, the snap ring 5311 is not provided, and the tip portion of the linear detection body 31 is held by the tip portion of the cylindrical portion 531 with an adhesive. The tip portion of the linear detection body 31 held by the cylindrical portion 531 corresponds to an example of the held portion. Note that the tip of the linear detection body 31 may be held in the cylindrical portion 531 by a holder such as a wiring clamp. In addition, by arranging retaining rings on the front end side of the linear detection body 31 and the rear end side of the linear detection body 31 to sandwich the linear detection body 31, the linear detection body 31 can be attached to the cylindrical portion 531. You can keep it. When retaining rings are arranged on the leading end side and the trailing end side, the portions of the leading end portion and the trailing end portion of the linear detection body 31 that are in contact with the retaining rings correspond to an example of the held portion. In this modification, the vibration or the like generated in the rotating body 52 is transmitted to the inner cylinder 53 via the rotary bush 57, and is in direct contact with the inner cylinder 53, or indirect contact with the inner cylinder 53 via a retaining ring or the like. It is transmitted to the linear detection body 31 . Therefore, the linear detection member 31 is deformed by vibration or the like transmitted to the inner cylinder 53 and outputs a signal having an intensity corresponding to the vibration or the like.

Next, the sensor arrangement structure of the third embodiment will be described. In the description of this third embodiment, mainly the structure different from that of the second embodiment will be described.

FIG. 12 is a cross-sectional view similar to FIG. 10 showing the sensor arrangement structure of the third embodiment. Also in FIG. 12, the hatching of the chuck 54, the leading end side bearing 55, and the trailing end side bearing 56 is omitted in order to make the drawing easier to see.

The sensor arrangement structure of the third embodiment differs from that of the second embodiment in that the inner cylinder 53 and the rotary bush 57 shown in FIG. different from As shown in FIG. 12 , the tip side bearing 55 has an outer ring 551 , balls 552 , a retainer 553 and an inner ring 554 . In the third embodiment, a spiral groove 5511 is formed in the outer peripheral surface 551a of the outer ring 551. As shown in FIG. The groove 5511 and the inner peripheral surface 51a of the outer cylinder 51 form a fourth internal space SD. This fourth internal space SD corresponds to an example of an accommodation space.

The sensor module 3 comprises a linear detection body 31 arranged within the fourth internal space SD and a signal line 33 extending outside the fourth internal space SD. That is, the linear detection body 31 is arranged on the tip side of the signal line 33 and has a spiral shape along the groove 5511 . The tip of the linear detection body 31 is held in the groove 5511 by a metal fitting (not shown). The tip of the linear detection body 31 held in this groove 5511 corresponds to an example of a held portion. Note that the tip of the linear detection body 31 may be held in the groove 5511 with an adhesive. The linear detection body 31 is disposed in the spiral fourth internal space by winding a linear body around the groove 5511 . However, the linear detection body 31 may be spirally shaped. The groove width and groove depth of groove 5511 are greater than the diameter of linear detection body 31 . Thereby, the linear detection body 31 can be deformed within the fourth internal space SD. Further, the tip of the linear detection body 31 is held in the groove 5511 and is spirally wound around the groove 5511 so that the linear detection body 31 is in contact with the groove 5511 . Vibration or the like generated in the rotating body 52 is transmitted to the outer ring 551 via the inner ring 554 and the ball 552 and transmitted to the linear detection body 31 in contact with the outer ring 551 . Therefore, the linear detection member 31 is deformed by vibration or the like transmitted to the outer ring 551 and outputs a signal having an intensity corresponding to the vibration or the like.

An inner peripheral surface 51a of the outer cylinder 51 is formed with a long groove 51b that extends from a portion where the front bearing 55 is press-fitted to the rear end of the outer cylinder 51 along the axial direction of the outer cylinder 51 . The signal line 33 has a front end portion disposed in a space formed by the long groove 51 b and a rear end portion extending outside the main shaft 5 . A rear end of the signal line 33 is connected to the control device 8 . Instead of passing the signal line 33 through the space formed by the long groove 51b, the signal line 33 may pass through an oil pipe not shown in FIG. In this case, since the long groove 51b does not need to be formed, there is an effect that the main shaft 5 can be constructed at low cost.

According to the third embodiment, similarly to the second embodiment, it is possible to grasp the life of the tool 58 and the state of deterioration of the tip end side bearing 55 and the rear end side bearing 56 . In addition, in the third embodiment, since the linear detection body 31 is arranged on the front end side bearing 55, vibrations and the like can be detected at a position closer to the tool 58 than when arranged on the rear end side bearing 56. . This also has the effect of making it easier to grasp changes such as vibration due to deterioration of the tool 58 .

The present invention is not limited to the above embodiments and modifications, and can be modified in various ways within the scope of the claims. For example, in the present embodiment, the linear detection body 31 holding the piezoelectric material between the inner conductor and the outer conductor was described as an example. It may be a piezo-resistive wire, a resistance wire, a capacitor wire, or an optical signal output wire, as long as it does. Further, the weight 42 shown in the second modification is attached to the tip of the spiral linear detection body 31 shown in the third modification or the double-coil linear detection body 31 shown in the fourth modification. good too. In addition, in the second and third embodiments, an example in which the sensor module 3 is arranged on the spindle 5 was shown, but a tool holder for detachably fixing the tool 58 to the spindle 5 has an accommodation space. However, the sensor module 3 composed of the linear detection body 31 and the wireless communication device may be arranged in the accommodation space. When this sensor module 3 is arranged in a tool holder, it is desirable to mount a battery in the sensor module 3 and to mount a function to charge the battery in a tool magazine storing a plurality of tools 58 . Since the battery of the sensor module 3 can be charged when the tool holder to which the tool 58 is attached is stored in the tool magazine, the sensor module can be used without stopping machining in a machining center that performs machining while switching between a plurality of tools. 3 can be charged. Furthermore, the sensor module 3 may be arranged on a member used in devices such as other machine tools, robots, agricultural machines, cars, and home appliances. For example, the sensor module can be applied to members with rotating shafts or bearings, such as robot joints, cultivator blade rotating parts, car axles, electric vehicle motor shafts and motor housings, vacuum cleaner fans, and washing machine rotating parts. 3 may be placed.

According to the embodiments and modifications described above, it is possible to perform detection with high detection sensitivity using the linear detection body 31 .

In addition, even if the constituent elements are included only in the descriptions of the embodiments and modifications described above, the constituent elements may be applied to other embodiments and other modifications.
The sensor arrangement structure described above includes a sensor module having a linear detection body,
and a member provided with an accommodation space,
The sensor module has a held portion held by the member,
The linear detection body is arranged in the accommodation space so as to be deformable, and outputs a signal having an intensity corresponding to the deformation state.
Further, in this sensor arrangement structure, a tension applying member may be provided for applying tension to the linear detection body within a range in which the linear detection body can be deformed.
The sensor placement method described above includes a preparation step of preparing a sensor module having a linear detection body that outputs a signal with an intensity corresponding to a deformation state, and a member having a housing space;
and an arranging step of causing the member to hold a part of the sensor module and arranging the linear detection body in the accommodation space so as to be deformable.
Further, in this sensor arrangement method, the preparing step may be a step of preparing the sensor module having the linear detection body twisted with a support wire.

2 screw 3 sensor module 31 linear detection body 32a both ends S accommodation space

Claims (5)

a sensor module having a linear detection body including an inner conductor, an outer conductor, and a piezoelectric body ;
a member provided with an accommodation space ;
a tension applying member that applies tension to the linear detection body within a range in which the linear detection body can be deformed ;
The sensor module has a held portion held by the member,
The sensor arrangement structure, wherein the linear detection body is arranged so as to be deformable in the accommodation space, and outputs a signal having an intensity corresponding to the deformation state. 2. The sensor arrangement structure according to claim 1, wherein said tension applying member is a support wire that is twisted around said linear detection body and applies tension to said linear detection body. 2. The sensor arrangement structure according to claim 1, wherein said linear detection body is formed in a spiral shape. A sensor module having a linear detection body comprising an inner conductor, an outer conductor, and a piezoelectric body and outputting a signal of strength corresponding to a deformation state; A preparation step of preparing a tension imparting member that imparts and a member having an accommodation space;
and an arranging step of causing the member to hold a part of the sensor module and arranging the linear detection body in the accommodation space so as to be deformable.. 5. The sensor arrangement method according to claim 4, wherein said preparing step is a step of preparing said sensor module having said linear detection member twisted with a support wire which is said tension applying member.

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