JP5578728B2 - Anti-vibration device capable of detecting external force - Google Patents

Description

  The present invention relates to a vibration isolator applied to, for example, a suspension bush of an automobile, and more particularly to a vibration isolator capable of detecting an input external force.

  2. Description of the Related Art Conventionally, a vibration isolator that is interposed between members constituting a vibration transmission system and that mutually vibrates and connects these members is known and applied to suspension bushes, member mounts, and the like. This vibration isolator generally has a structure in which a first attachment member and a second attachment member are elastically connected by a main rubber elastic body. For example, the first attachment member is attached to a vehicle body. At the same time, the second attachment member is attached to the suspension arm or the subframe, so that the suspension arm or the subframe is connected to the vehicle body in a vibration-proof manner.

  By the way, in recent years, by sensing the running state of the vehicle and using the sensing result for vehicle control, it is possible to prevent skidding during running, appropriate torque control during acceleration, efficient braking, etc. Research has been made to help, and it has also been proposed to attach a sensor for sensing the running state to the vibration isolator. For example, Japanese Patent No. 4347784 (Patent Document 1) discloses a structure in which strain detection means is provided on at least one of an inner shaft member and an outer cylinder member. Japanese Patent No. 4415390 (Patent Document 2) discloses a cylindrical vibration isolator in which a plurality of rubber sensors are mounted via a ring-shaped fixing member.

  However, in the structure of Patent Document 1, any one of the inner shaft member and the outer cylinder member that is an attachment portion to another member is detected, and the inner shaft member and the outer cylinder member are load resistant. Therefore, it is difficult to generate sufficient distortion with a minute input, and it is difficult to detect with high accuracy. On the other hand, in the structure of Patent Document 2, there is a possibility that a special structure for mounting the sensor on the vibration isolator side may be required, and a special fixing member is also required on the sensor side, which increases the number of parts. In some cases, the complexity of the structure becomes a problem.

Japanese Patent No. 4347784 Japanese Patent No. 4415390

  The present invention has been made in the background of the above-mentioned circumstances, and its solution problem is a novel technique capable of realizing highly accurate detection of an input load with sufficient durability and practicality. An object of the present invention is to provide a vibration isolator capable of detecting an external force having a simple structure.

That is, according to the first aspect of the present invention, an outer cylindrical member as a second mounting member is extrapolated to an inner shaft member as a first mounting member, and between the inner shaft member and the outer cylindrical member. in the vibration isolating apparatus main rubber elastic body is connected is arranged, the electrostatic capacitance type in which a pair of electrode films made of a conductive elastic material with respect to both surfaces of the dielectric layer made of a dielectric elastic material using the sensor, extending in the opposing direction of the inner shaft member and the outer cylindrical the main rubber elastic which is acting direction of the tensile force to the body the inner shaft member and the outer tubular member when the external force acting on between the member with electrostatic capacity-type sensor is disposed in a state, electrostatic capacity type sensor is characterized in that it is secured to the axial end surface of the rubber elastic body.

  In the vibration isolator having the structure according to this aspect, the dielectric layer and the electrode film of the capacitive sensor are both formed of an elastic material, so that the elasticity of the main rubber elastic body is exerted when an external force is applied. Along with the deformation, the dielectric layer and the electrode film of the capacitive sensor elastically expand and contract. As a result, a change in capacitance (ΔC) of the capacitive sensor is caused in accordance with the change in the thickness of the dielectric layer and the change in the area of the electrode film accompanying the expansion and contraction. Since the amount of change in capacitance corresponds to the amount of elastic deformation of the main rubber elastic body, the amount of change in capacitance acts on the main rubber elastic body based on the elastic deformation characteristics of the main rubber elastic body. External force can be calculated.

  In particular, in the present invention, both the dielectric layer and the electrode film constituting the capacitive sensor are formed of an elastic material, and the capacitive sensor is fixed to the main rubber elastic body. Therefore, the capacitive sensor is elastically deformed integrally with the main rubber elastic body. As a result, the amount of elastic deformation of the main rubber elastic body can directly appear as the amount of elastic deformation of the capacitive sensor, so that it is possible to detect external force with high accuracy.

  In addition, by fixing the capacitive sensor to the main rubber elastic body, it is possible to attach the capacitive sensor while preventing the vibration isolator from increasing in size, and the main rubber elastic body for the capacitive sensor. The protective effect by can also be expected. That is, when it is fixed to the surface of the main rubber elastic body, local deformation of the dielectric layer and the electrode film is prevented by the main rubber elastic body, and an effect such as improvement of durability is expected. Is done. Furthermore, if the capacitive sensor is fixed in an embedded state within the rubber elastic body of the main body, or if the capacitive sensor disposed on the surface of the main rubber elastic body is covered with an adhesive layer or the like and fixed, Damage due to contact of other members with the capacitive sensor can also be prevented.

  In addition, it can detect directly by arrange | positioning an electrostatic capacitance type sensor so that it may extend in the main direction of the elastic deformation induced by the main body rubber elastic body with respect to the external force to detect. In addition, when there are a plurality of external force directions to be detected and they are input simultaneously (in a mutual interference manner), a plurality of sensors are extended so as to extend in the direction of the action of a plurality of tensile forces induced on the main rubber elastic body. By disposing, the relationship between the external force and the change in capacitance of the capacitive sensor is expressed by simultaneous equations, and the external force in each direction can be obtained by solving the simultaneous equations. At this time, the position, direction, and number of sensor arrangements may be set so that external forces in a plurality of directions can be specified (so that a solution of simultaneous equations can be obtained).

A vibration damping device capable of detecting external force according to the first aspect of the present invention, the outer tubular member as the second mounting member to the inner shaft member as said first attachment member is extrapolated The elastic rubber body is disposed between the inner shaft member and the outer cylinder member, and the capacitance type sensor is disposed in a state extending in the opposing direction of the inner shaft member and the outer cylinder member. The embodiment is adopted.

In the case of a cylindrical vibration isolator, the inner rubber elastic body has an inner shaft for input in the direction perpendicular to the axis, input in the axial direction, input in the axis tilt direction (twist direction), and input in the circumferential direction around the axis (torsion direction). A tensile force acts in the opposing direction of the member and the outer cylinder member. Therefore, according to the first aspect, it is possible to detect the external force in the direction perpendicular to the axis and the external force in the axial direction by the capacitance sensor arranged so as to extend in the opposing direction of the inner shaft member and the outer cylindrical member. It becomes.

A vibration damping device capable of detecting external force according to the first aspect of the present invention may include a mode where the capacitive sensor is fixed to the axial end surface of the main rubber elastic body, is employed.

According to the 1st aspect, mounting | wearing of a sensor becomes easy by adhering an electrostatic capacitance type sensor to the surface of a main body rubber elastic body. In addition, since the deformation amount of the main rubber elastic body is larger at the surface than at the intermediate portion, highly accurate sensing can be performed with respect to the input in the twisting direction.

  The capacitive sensor is attached to the surface of the rubber elastic body of the main body by sticking it to the inner surface of the molding cavity of the main rubber elastic body and vulcanizing the outer surface of the main rubber elastic body at the same time as vulcanization molding. It is realized by bonding or bonding to the surface of the main rubber elastic body after vulcanization molding of the main rubber elastic body.

According to a second aspect of the present invention, there is provided a vibration isolator capable of detecting an external force as described in the first aspect, wherein the inner shaft member is arranged in a radial direction at end surfaces on both axial sides of the main rubber elastic body. A pair of the electrostatic capacity type sensors arranged with the inner shaft member interposed therebetween and another pair of the electrostatic capacity type sensors disposed with the inner shaft member sandwiched in another radial direction are disposed. is there.

According to the 2nd aspect, in a cylindrical vibration isolator, external force can be detected efficiently with few sensors. Preferably, a mode is adopted in which the opposing radial lines of the pair of sensors and the other pair of sensors are orthogonal to each other, thereby improving detection accuracy.

According to a third aspect of the present invention, in the vibration isolator capable of detecting an external force described in the first or second aspect, each of the main rubber elastic bodies is twisted at a position separated by a predetermined distance in the axial direction. The capacitive sensor is disposed so as to be paired on the tensile deformation side and the compression deformation side in accordance with the input of an external force in the direction.

According to the 3rd aspect, in a cylindrical vibration isolator, it can respond (detect) when the external force which should be detected is a twist direction. In addition, it is desirable to arrange a pair of capacitive sensors so as to face each other in the twisting direction to be detected, so that detection accuracy can be improved. In addition, it is preferable to improve the detection accuracy by disposing the pair of capacitive sensors as far apart as possible in the axial direction.

A fourth aspect of the present invention is the vibration isolator capable of detecting an external force described in any one of the first to third aspects, wherein the main rubber elastic body has a central axis of the inner shaft member. The capacitive sensor is disposed so that a pair of a position biased on one side in the circumferential direction and a position biased on the other side in the circumferential direction are paired with respect to the radial line passing through is there.

According to the 4th aspect, in a cylindrical vibration isolator, it can respond (detect) when the external force which should be detected is a twist direction. In other words, depending on the input torsional direction (circumferential direction), there is a difference in the amount of change in the capacitance of the capacitive sensor that makes a pair, so the direction of torsional input can be specified. Become.

  Moreover, since it is realized only by devising the arrangement of the capacitive sensor, it is possible to avoid a complicated structure, an increase in size, an increase in the number of parts, and the like.

According to a fifth aspect of the present invention, in the vibration isolator capable of detecting an external force described in any one of the first to third aspects, the capacitive sensor is arranged on a central axis of the inner shaft member. It has an inclination angle in the circumferential direction around the central axis of the inner shaft member with respect to an orthogonal plane.

According to the fifth aspect, the area of the capacitive sensor (electrode film) is increased while suppressing a decrease in detection accuracy due to an increase in the projected area in the axial direction of the capacitive sensor (electrode film). Therefore, the detection accuracy can be improved.

According to a sixth aspect of the present invention, in the vibration isolator capable of detecting an external force described in any one of the first to fifth aspects, the capacitance type sensor with respect to a surface of the main rubber elastic body. Is fixed, and a protective layer covering the capacitance type sensor is formed of an insulating elastic material.

According to the sixth aspect, by disposing the sensor in close contact with the surface of the main rubber elastic body, the sensor can be easily mounted without adversely affecting the characteristics of the main rubber elastic body. The protective layer may be an insulating rubber elastic body or a resin elastomer, and is preferably fixed or integrated with the main rubber elastic body around the capacitive sensor. Thereby, improvement of the adhering force to the main rubber elastic body of the sensor can be achieved by using the protective layer.

According to a seventh aspect of the present invention, in the vibration isolator capable of detecting an external force described in any one of the first to sixth aspects, the pair of electrode films are formed of rubber-based conductive ink. It is.

According to the seventh aspect, it is possible to easily realize an elastic electrode film that can follow the large deformation of the main rubber elastic body. In addition, a thin electrode film can be easily formed, and a small and lightweight capacitive sensor is realized.

According to an eighth aspect of the present invention, in the vibration isolator capable of detecting an external force described in any one of the first to seventh aspects, the dielectric layer and the pair of electrode films are both 10% or more. It is formed of an elastic material that is allowed to expand and contract.

According to the eighth aspect, both the dielectric layer and the pair of electrode films have a sufficiently large stretchability of 10% or more with respect to the time when no external force is applied. An electrostatic capacity sensor capable of following large deformation and having excellent elasticity is realized.

  According to the present invention, based on the elastic deformation characteristics of the main rubber elastic body, the external force acting on the main rubber elastic body can be determined from the amount of change in capacitance (ΔC). In addition, since the dielectric layer and the electrode film constituting the capacitive sensor are both formed of an elastic material and fixed to the elastic body of the main body, an increase in the size of the vibration isolator is avoided. The durability of the capacitive sensor is ensured. In addition, since the elastic deformation amount of the main rubber elastic body is directly set as the elastic deformation amount of the capacitive sensor, highly accurate sensing is also realized.

The front view which shows the suspension bush as one Embodiment of this invention. The rear view of the suspension bush shown by FIG. III-III sectional drawing of FIG. IV-IV sectional drawing of FIG. FIG. 2 is a front view of a capacitance type sensor constituting the suspension bush shown in FIG. 1. FIG. 6 is a rear view of the capacitive sensor shown in FIG. 5. VII-VII sectional drawing of FIG. FIG. 2 is a graph showing a change in capacitance in the suspension bush shown in FIG. 1, where (a) shows an actual value obtained by conducting an excitation test on the suspension bush, and (b) shows a calculated value by simulation. , Respectively.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 4 show a suspension bush 10 for an automobile as an embodiment of a vibration isolator capable of detecting an external force of a structure according to the present invention. The suspension bush 10 has a structure in which an inner shaft member 12 as a first attachment member and an outer cylinder member 14 as a second attachment member are elastically connected by a main rubber elastic body 16. The inner shaft member 12 is bolted to a vehicle body (not shown), and the outer cylinder member 14 is press-fitted and fixed to an arm eye of a suspension arm (not shown), so that the suspension arm is connected to the vehicle body in a vibration-proof manner. It is like that.

  More specifically, the inner shaft member 12 is a highly rigid member formed of iron, aluminum alloy, or the like, and has a substantially cylindrical shape that linearly extends with a thick small diameter. On the other hand, the outer cylinder member 14 has a thin, large-diameter, generally cylindrical shape, and is a highly rigid member formed of the same material as the inner shaft member 12.

  The inner shaft member 12 and the outer cylinder member 14 are arranged in an externally inserted state with a predetermined distance in the radial direction, and the main rubber elastic body 16 is interposed between the inner shaft member 12 and the outer cylinder member 14. Is intervening. The main rubber elastic body 16 has a thick, large-diameter, generally cylindrical shape, and its inner peripheral surface is vulcanized and bonded to the outer peripheral surface of the inner shaft member 12, and the outer peripheral surface is the inner cylinder member 14. It is vulcanized and bonded to the peripheral surface.

  A capacitive sensor 18 is attached to the axial end surface of the main rubber elastic body 16. As shown in FIGS. 5 to 7, the capacitive sensor 18 has a structure in which electrode films 22 a and 22 b are fixed to both surfaces of the dielectric layer 20. In addition, what was described in Unexamined-Japanese-Patent No. 2010-43880 is employ | adopted suitably as the electrostatic capacitance type sensor 18 of the suspension bush 10. FIG.

  That is, the dielectric layer 20 is formed of a dielectric elastic material such as rubber or thermoplastic elastomer, and the substantially rectangular film-like electrode fixing portion 24 and the electric wire support portion 26 extending from the electrode fixing portion 24 are integrated. It is in the form of a specially prepared band. The material for forming the dielectric layer 20 is not particularly limited as long as it is a dielectric elastic material. However, in order to increase the capacitance of the capacitive sensor 18, a material having a high relative dielectric constant is desirable. For example, a material having a relative dielectric constant of 3 or more at room temperature, more preferably 5 or more is employed.

  Examples of the material for forming the dielectric layer 20 include elastomers having polar functional groups such as ester groups, carboxyl groups, hydroxyl groups, halogen groups, amide groups, sulfone groups, urethane groups, and nitrile groups, and polar functional groups thereof. An elastomer to which a polar low molecular weight compound is added is preferably employed. Furthermore, by setting the Young's modulus of the elastomer to a small value, the capacitance type sensor 18 capable of detecting minute external forces can be realized. For example, the Young's modulus of the elastomer can be set appropriately according to the required detection sensitivity and detection range. Is done.

  More specifically, as a material for forming the dielectric layer 20, for example, silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber and the like are preferable. Adopted. The dielectric layer 20 of this embodiment is formed of urethane rubber.

  Further, the thickness of the dielectric layer 20 is not particularly limited, but it is desirable that the dielectric layer 20 be thin in order to realize a reduction in size of the capacitive sensor 18 and an improvement in detection sensitivity, and preferably 1 μm. More than and 5000 μm or less, more preferably 20 μm or more and 500 μm or less. If the dielectric layer 20 is too thin, it becomes difficult to manufacture and the leakage current increases and the detection accuracy decreases, so it is desirable that the thickness of the dielectric layer 20 be set in the above range. .

  A pair of electrode films 22 and 22 are superimposed on the electrode fixing portion 24 of the dielectric layer 20 formed into a film shape. The electrode film 22 is formed of an elastic material having conductivity such as an elastomer filled with a conductive filler, and is a thin film having a rectangular shape in plan view. Furthermore, the electrode film 22 is preferably formed of the same elastomer as that of the dielectric layer 20, thereby improving the followability to the deformation of the dielectric layer 20 and improving the adhesion to the dielectric layer 20. Even if it is repeatedly deformed, peeling from the dielectric layer 20 is avoided, and reliability can be improved.

  The electrode film 22 is formed with a thickness of 1 μm or more and 100 μm or less in consideration of ease of manufacture, followability to deformation of the dielectric layer 20 and downsizing of the entire capacitive sensor 18. Is desirable. Furthermore, in order to realize excellent followability with respect to deformation of the dielectric layer 20, the Young's modulus of the electrode film 22 is preferably set to 0.1 MPa or more and 200 MPa or less. In addition, the electrode film 22 desirably has an expansion / contraction ratio that can allow a change in length of 10% or more during elastic deformation, and more preferably when the electrode film 22 is cut in a tensile test (JIS K6251). By setting the elongation to 30% or more, sufficient deformation followability is ensured.

  Further, the electric resistance of the electrode film 22 is desirably 100 kΩ or less, more preferably 10 kΩ or less in the thickness direction and the surface direction. Furthermore, the electrode film 22 desirably has a small change in conductivity due to expansion and contraction.

  As the elastomer composition for forming the electrode film 22, it is desirable to use a composition having a critical volume fraction (φc) of 25 vol% or less in a percolation curve when a mixture of an elastomer and a conductive filler is prepared. According to this, even when the blending amount of the conductive filler is relatively small, an electrode film having high conductivity can be obtained.

  The elastomer forming the electrode film 22 is not particularly limited. For example, silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber Epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber and the like are preferably employed.

  The conductive filler mixed with the elastomer may be particles having conductivity, and fine particles such as carbon material and metal are used alone or in the form of a mixture of a plurality of types of fine particles. For example, as the conductive filler, a carbon material is preferably used because it is relatively inexpensive and the formation of a conductive path is easy, and carbon such as ketjen black having a small particle diameter and excellent cohesiveness is used. Black is preferably employed to achieve excellent conductivity.

  Moreover, the fine particle shape of the conductive filler is not particularly limited, and various shapes such as a spherical shape, a cone shape, and a column shape can be arbitrarily adopted. However, in order to ensure the conductivity efficiently with a small amount and suppress the change in conductivity due to the deformation of the electrode film 22, the aspect ratio of the conductive filler (the ratio of the length of the long side to the length of the short side) Is preferably large, and the aspect ratio is preferably set to 1 or more.

  The average particle size of the conductive filler is preferably 0.01 μm or more and 0.5 μm or less, and more preferably 0.03 μm or more and 0.1 μm or less. When the lid is covered and the average particle diameter of the conductive filler is too small, the cohesiveness of the particles becomes too high, and it becomes difficult to uniformly disperse the elastomer in the electrode film 22. On the other hand, if the average particle size of the conductive filler is too large, the cohesiveness of the particles becomes too low and the formation of the conductive network tends to be insufficient.

  Further, considering the ease of mixing the conductive filler into the elastomer, the volume ratio of the conductive filler to the volume of the electrode film 22 is desirably 30 vol% or less, and the electrode film 22 has excellent conductivity. In order to ensure stretchability, it is more preferably 25 vol% or less, and further preferably 15 vol% or less. In addition, the conductive filler is blended at a ratio equal to or higher than the volume ratio (critical volume fraction) at which the electrical resistance of the electrode film 22 rapidly decreases and the insulator-conductor transition occurs.

  In addition, although the electrode film 22 is formed by mixing the conductive filler with the elastomer as described above, various additives may be mixed in addition to them. Examples of the additive include a crosslinking agent, a vulcanization accelerator, a vulcanization aid, an antiaging agent, a plasticizer, a softening agent, and a colorant.

  The electrode film 22 is fixed to both surfaces in the thickness direction with respect to the electrode fixing portion 24 of the dielectric layer 20. The electrode film 22 may be formed into a thin film in advance and fixed to the surface of the dielectric layer 20, but in this embodiment, a rubber-based conductive ink in which a conductive filler is mixed with a liquid rubber material is used. For example, it is formed by printing on the surface of the dielectric layer 20 by a method such as screen printing, ink jet printing, flexographic printing, gravure printing, pad printing, or lithography.

  An electric wire 28 is connected to the electrode film 22. The electric wire 28 is desirably extendable and contractible. For example, a conductor in which a conductive filler is dispersed in an elastomer may be employed. Note that the elastomer and conductive filler of the electric wire 28 can be the same as those of the electrode film 22, but may be formed of a material different from that of the electrode film 22. In the present embodiment, the electric wires 28 are integrally formed of the same material as the electrode film 22, and the surfaces of the electrode films 22 and the electric wires 28 are covered with an insulating coating 30 formed of an insulating elastomer. The electric wire 28 is fixed to both surfaces of the electric wire support portion 26 of the dielectric layer 20 by printing or adhesion similar to the electrode film 22, and the pair of electric wires 28 and 28 are insulated from each other by the dielectric layer 20. Yes. 5 and 6, the insulating film 30 is shown in a transparent state so that the structure of the capacitive sensor 18 can be easily understood, and the reference numerals are omitted.

  The capacitance type sensor 18 having such a structure is superimposed on the axial end face of the main rubber elastic body 16 and is protected by the protective layer 32 formed on the axial end face of the main rubber elastic body 16. The rubber elastic body 16 is fixed. The protective layer 32 is formed of an elastic material having electrical insulation, and is the same as the elastomer that forms the dielectric layer 20 of the capacitive sensor 18 so as not to hinder the deformation of the capacitive sensor 18. Since a low-elastic elastomer is suitably employed, in this embodiment, it is made of urethane rubber. The protective layer 32 is molded in a state in which the capacitive sensor 18 is disposed on the axial end surface of the main rubber elastic body 16, thereby fixing the capacitive sensor 18 to the main rubber elastic body 16. The adhesive is a caulking adhesive and covers and protects the surface of the capacitive sensor 18. The protective layer 32 secures the capacitance type sensor 18 to the main rubber elastic body 16 when the capacitance type sensor 18 is previously bonded to the main rubber elastic body 16 with an adhesive. It does not have to have a function as an adhesive. In this case, as a material for forming the protective layer 32, a material that can insulate the surface of the capacitive sensor 18 from the outside and can exhibit a buffering action when contacting other members is appropriately selected. Can be adopted.

  In addition, four capacitive sensors 18a, 18b, 18c, and 18d are disposed at substantially equal intervals in the circumferential direction on one end face in the axial direction of the main rubber elastic body 16. Four capacitive sensors 18e, 18f, 18g, and 18h are spaced apart from each other in the circumferential direction on the other end surface in the axial direction of the main rubber elastic body 16, and extend in the radial direction. . Each of these capacitive sensors 18a to 18h is arranged such that the long side direction of the electrode film 22 substantially coincides with the opposing direction (radial direction) of the inner shaft member 12 and the outer cylinder member 14. The expansion / contraction deformation with respect to the radial input is sufficiently larger than the expansion / contraction deformation with respect to the circumferential or axial input.

  More specifically, on one end surface in the axial direction of the main rubber elastic body 16, the capacitive sensors 18 a and 18 c are disposed opposite to each other with the inner shaft member 12 interposed therebetween in the direction perpendicular to the axis, and the electrostatic capacitance. The mold sensors 18b and 18d are opposed to each other with the inner shaft member 12 interposed therebetween in a direction perpendicular to the axis perpendicular to the facing direction of the capacitance sensors 18a and 18c. By arranging the capacitive sensors 18a to 18d in this way, the capacitive sensor 18a and the capacitive sensor 18c are in the direction of compression deformation against the action of an external force in one direction (opposite direction) and tensile. In addition to being paired on the deformation side, the capacitance type sensor 18b and the capacitance type sensor 18d are paired on the compression deformation side and the tensile deformation side with respect to the action of external force in another radial direction (opposite direction). ing. As shown in FIG. 1, capacitance sensors 18a, 18b, 18c, and 18d are sequentially arranged clockwise in the circumferential direction.

  Further, on the other end surface in the axial direction of the main rubber elastic body 16, the capacitive sensors 18e and 18g are disposed opposite to each other with the inner shaft member 12 interposed therebetween in the direction perpendicular to the axis, and the capacitive sensor 18f. , 18h are opposed to each other with the inner shaft member 12 interposed therebetween in a direction perpendicular to the axis perpendicular to the facing direction of the capacitive sensors 18e, 18g. By disposing the capacitive sensors 18e to 18h in this way, the capacitive sensor 18e and the capacitive sensor 18g are compressed and deformed against the action of an external force in one radial direction (opposite direction). In addition to being paired on the deformation side, the capacitance type sensor 18f and the capacitance type sensor 18h are paired on the compression deformation side and the tensile deformation side with respect to the action of external force in another radial direction (opposite direction). ing. As shown in FIG. 2, capacitance sensors 18e, 18f, 18g, and 18h are sequentially arranged clockwise in the circumferential direction.

  Further, the capacitance type sensor 18a and the capacitance type sensor 18e are arranged at corresponding positions on the circumference and face each other in the substantially axial direction, and the capacitance type sensor 18a and the capacitance type sensor 18e are twisted. They are arranged so as to be paired on the tensile deformation side and the compression deformation side accompanying external force input in the direction. Similarly, the electrostatic capacity sensor 18b and the electrostatic capacity sensor 18f, the electrostatic capacity sensor 18c and the electrostatic capacity sensor 18g, and the electrostatic capacity sensor 18d and the electrostatic capacity sensor 18h are respectively on the circumference. They are arranged at corresponding positions and are opposed to each other in the substantially axial direction, and they are arranged so as to be paired on the tensile deformation side and the compression deformation side in accordance with the external force input in the twisting direction.

  Furthermore, the capacitive sensors 18e, 18f, 18g, and 18h are arranged at positions slightly shifted in the circumferential direction with respect to the capacitive sensors 18a, 18b, 18c, and 18d. That is, the position is biased to one side in the circumferential direction (the side that has advanced counterclockwise in the circumferential direction) with respect to the radial line (the radial line extending in the left and right direction in FIG. 2) passing through the central axis of the inner shaft member 12 Capacitance type sensors 18e and 18g and a radial line (a radial line extending vertically in FIG. 2) passing through the central axis of the inner shaft member 12 on the other side in the circumferential direction (clockwise in the circumferential direction). Capacitance type sensors 18f and 18h that are biased to the advanced side are disposed on the axial end surface of the main rubber elastic body 16 so as to form a pair. In other words, as shown in FIG. 2, the circumferential distance between the capacitance type sensor 18e and the capacitance type sensor 18f, and the capacitance type sensor 18g and the capacitance type sensor 18h. The separation distance in the circumferential direction is increased, the separation distance in the circumferential direction between the capacitive sensor 18e and the capacitive sensor 18h, and the circumferential direction between the capacitive sensor 18f and the capacitive sensor 18g. Each of the capacitive sensors 18e to 18h is arranged so that the separation distance at is reduced.

  Further, the capacitive sensors 18e, 18f, 18g, and 18h are inclined in the circumferential direction at a predetermined angle with respect to a virtual plane extending in a direction orthogonal to the central axis of the inner shaft member 12, respectively. Yes. In other words, the capacitance type sensors 18e, 18f, 18g, and 18h have a circumferential end on the radial line passing through the central axis of the inner shaft member 12 described above as compared with the other circumferential end. Projects outward in the axial direction. This inclination angle is set by fixing the capacitive sensors 18e, 18f, 18g, and 18h to the slope of the protrusion 34 that is formed to protrude from the axial end surface of the main rubber elastic body 16. The protrusion 34 has a mountain shape with a radial line passing through the central axis of the inner shaft member 12 as a ridge line, and four protrusions 34 are formed on the circumference. Then, the capacitive sensor 18 is fixed to any one of the slopes in the circumferential direction of the protrusion 34, whereby the capacitive sensors 18e, 18f, 18g, and 18h are arranged at a predetermined inclination angle. Yes. Note that the inclination angles of the capacitive sensors 18e, 18f, 18g, and 18h are arbitrarily set in a range from 0 degrees to 90 degrees, preferably 5 degrees to 45 degrees, more preferably 10 degrees or more. It is set to 30 degrees or less.

  In each of the capacitive sensors 18 arranged in the above-described manner on the axial end surface of the main rubber elastic body 16, the electric wires 28 extending to the outer peripheral side are exposed from the protective layer 32 and are not shown outside. It is connected to the. As a result, when the main rubber elastic body 16 is elastically deformed by the input of an external force, an output signal based on the change in the capacitance of the capacitance type sensor 18 is input to the processing device through the electric wire 28. ing.

  In the processing apparatus, the magnitude and direction of the input vibration are specified based on the signal transmitted from the capacitive sensor 18. More specifically, the magnitude and direction of the input external force are specified by an arithmetic process based on the mathematical formula shown in [Equation 1]. In [Equation 1], ΔC is the amount of change in capacitance detected by each of the capacitance sensors 18a to 18h, and which sensor is shown in parentheses. Furthermore, Fx is an external force (external force in the direction perpendicular to the axis) acting in the x-axis direction (left-right direction in FIG. 1), and Fy is an external force (another axis perpendicular to the axis in FIG. 1) acting in the y-axis direction (vertical direction in FIG. 1). Fz represents the external force (axial external force) acting in the z-axis direction (in FIG. 1, the direction perpendicular to the paper surface), and Mx represents the moment around the x-axis (rotation in the twisting direction). Force), My represents a moment around the y-axis (rotational force in another twisting direction), and Mz represents a moment around the z-axis (rotational force in the torsional direction). The x-axis and the y-axis are indicated by a one-dot chain line in FIG. 1, and the z-axis is indicated by a one-dot chain line in FIG.

Therefore, in order to obtain the matrix A of the mathematical formula shown in [Equation 1], the matrix A ′ of the mathematical formula shown in [Equation 2] is calculated in advance. This matrix: A ′ is an 8 × 6 matrix, as shown in [Equation 3], and the _ij component is a _ij . A ′ is an inverse matrix of A. That is, A = A ′ ⁻¹ .

According to [Equation 2] and [Equation 3], the change amount of capacitance of the capacitive sensor 18a: ΔC _(a) is ΔC _(a) = a ₁₁ Fx + a ₁₂ Fy + a ₁₃ Fz + a ₁₄ Mx + a ₁₅ My + a ₁₆ Mz. In this case, ΔC _(a) = a ₁₁ Fx if limited to only the input (Fx) in the x-axis direction, and ΔC _(a) = a ₁₂ if limited only to the input (Fy) in the y-axis direction. Fy.

Here, as shown in FIG. 1, the capacitive sensor 18a is arranged so that the x-axis direction is long, and if the input is the same, the deformation amount in the x-axis direction is the same. Is larger than the amount of deformation in the y-axis direction, the amount of change in capacitance with respect to input in the x-axis direction is sufficiently larger than the amount of change in capacitance with respect to input in the y-axis direction (a ₁₁ >> a _12). In this embodiment, if the inputs are the same (Fx = Fy), the amount of change in capacitance with respect to the input in the y-axis direction can be ignored as compared to the amount of change in capacitance with respect to the input in the x-axis direction. Since it is so small, the amount of change in capacitance with respect to the input in the y-axis direction is approximated to 0 (a ₁₂ Fy≈0). Furthermore, since it is Fy ≠ 0 assumption, a ₁₂ is substantially zero.

By a similar calculation for the other of each capacitive sensor _{18b~18h, a 21 = 0, a} 22 = a 11, a 31 = a 11, a 32 = 0, a 41 = 0, a 42 the _{= a 11, a 52 = 0} , a 61 = 0, a 62 = a 51, a 71 = a 51, a 72 = 0, a 81 = 0, a 82 = a 51, obtained respectively. Then, by adjusting the code in consideration of the arrangement of the capacitive sensor _{18a~18h, a 31 = -a 11,} a 42 = -a 11, a 71 = -a 51, a 82 = -a 51 It is said.

Then, if limited input only to the z-axis direction, since the amount of change in the capacitance of the anchored capacitive sensor 18a~18d on one end face in the axial direction is identical to each other, a ₁₃ = a ₂₃ = a ₃₃ = become a _43. On the other hand, since the amount of change in capacitance of the capacitive sensors 18e to 18h fixed to the other end surface in the axial direction is the same, a ₅₃ = a ₆₃ = a ₇₃ = a ₈₃ . In the present embodiment, since the capacitance type sensor 18e~18h is inclined with respect to the capacitive sensor 18a to 18d, there is a a ₁₃ ≠ a _53. By these, the matrix: A ′ shown in [Equation 4] is obtained.

Further, when it is assumed that only the moment about the x axis: Mx is input, the amount of change in the capacitance of the capacitance type sensors 18a to 18h: ΔC _{(a) to} ΔC _(h) is expressed by [Equation 5]. Is obtained. On the other hand, when it is assumed that only the moment about the y-axis: My is input, the amount of change in the capacitance of the capacitance sensors 18a to 18h: ΔC _{(a) to} ΔC _(h) is as shown in [Formula 6]. Is obtained.

In [Equation 5], if the arrangement of the capacitive sensors 18a to 18d and the acting direction of the moment are taken into consideration, the amount of change in the electrostatic capacitance of the capacitive sensors 18a and 18c is the capacitive sensor 18b. , 18d is sufficiently smaller than the amount of change in capacitance, and ΔC _(a) and ΔC _(C) can be regarded as substantially zero. In addition, since Mx ≠ 0 as a premise, a ₁₄ = a ₃₄ ≈0. On the other hand, the capacitance type sensor 18e and the capacitance type sensor 18g are disposed on one side of the x axis so that a change in capacitance is detected during the action of Mx. Further, in consideration of the arrangement of the capacitive sensors 18a to 18h, ΔC _(d) = − ΔC _{( b)} , ΔC _(g) = − ΔC _{( e)} , ΔC _(h) = − ΔC _(f) Therefore, a ₄₄ = −a ₂₄ , a ₇₄ = −a ₅₄ , a ₈₄ = −a ₆₄ .

Further, in [Equation 6], if the arrangement of the capacitive sensors 18a to 18d and the acting direction of the moment are taken into consideration, the amount of change in the electrostatic capacitance of the capacitive sensors 18b and 18d is the capacitive type. The amount of change in the capacitance of the sensors 18a and 18c is sufficiently small, and both ΔC _(b) and ΔC _(d) can be regarded as substantially zero. In addition, since My ≠ 0 as a premise, a ₂₅ = a ₄₅ ≈0. On the other hand, the capacitance type sensor 18f and the capacitance type sensor 18h are disposed on one side of the y axis, so that a change in capacitance is detected when My operates. Further, in consideration of the arrangement of the capacitive sensors 18a to 18h, ΔC _(C) = − ΔC _{( a)} , ΔC _(g) = − ΔC _{( e)} , ΔC _(h) = − ΔC _(f) Therefore, a ₃₅ = −a ₁₅ , a ₇₅ = −a ₅₅ , a ₈₅ = −a ₆₅ .

Furthermore, in [Equation 5] and [Equation 6], considering the arrangement of the capacitive sensors 18a to 18h with respect to the direction of the external force, ΔC _(a) at the time of Mx input and ΔC _(b) at the time of My input. Since Mx and My are equal if they have the same size, a ₂₄ = a ₁₅ . Similarly, a ₅₄ = a ₆₅ and a ₆₄ = a ₅₅ . Then, the matrix of [Equation 7] is obtained by adjusting the sign of each term in consideration of the deformation mode of the capacitive sensors 18a to 18h with respect to the direction of the external force.

Further, when it is assumed that only the moment about the z-axis: Mz is input, the amount of change in capacitance of the capacitive sensors 18a to 18h: ΔC _{(a) to} ΔC _(h) Is obtained as follows. In [Equation 8], if attention is paid to the fact that the capacitive sensors 18a to 18d are arranged at equal intervals in the circumferential direction, the output is the same for the moment input about the z axis regardless of the direction of the moment. (A ₁₆ = a ₂₆ = a ₃₆ = a ₄₆ ). On the other hand, the capacitive sensors 18e to 18h are fixed to the inclined surface of the protrusion 34 where the capacitive sensor 18e and the capacitive sensor 18g are located on the same side (one side) in the circumferential direction. The capacitance type sensor 18f and the capacitance type sensor 18h are fixed to the slope of the protrusion 34 located on the same side (the other side) in the circumferential direction. With such sensor arrangement, the amount of change in capacitance (a ₅₆ Mz) of the capacitance sensors 18e and 18g and the change in capacitance of the capacitance sensors 18f and 18h with respect to the moment input around the z-axis. The amounts (a ₆₆ Mz) are different, and a ₅₆ and a ₆₆ are different from each other. The direction of the moment about the z-axis is specified based on the difference between the capacitance change amounts of the capacitance sensors 18e and 18g and the capacitance change amounts of the capacitance sensors 18f and 18h. It is like that.

  Such a difference in the amount of change in capacitance is considered to occur for the following reason. That is, when a moment in the circumferential direction: Mz is input, either one of the capacitive sensors 18e and 18g and the capacitive sensors 18f and 18h can be used in either the x-axis direction or the y-axis direction. Since it is expanded, the amount of change in capacitance increases. On the other hand, either one of the capacitive sensors 18e and 18g and the capacitive sensors 18f and 18h is expanded in either the x-axis direction or the y-axis direction, and at the same time, in the x-axis direction and the y-axis direction. Since either one of them is contracted, the amount of change in capacitance is canceled out and becomes smaller. In the present embodiment, the outputs of the capacitive sensors 18e and 18g and the capacitive sensors 18f. By comparing the output of 18h, the direction of the input moment about the z-axis: Mz is specified, and the magnitude of Mz is calculated from one of the outputs having a large capacitance change amount. It has become.

Thus, the matrix: A ′ is obtained as [Equation 9], and the matrix: A is calculated based on A ′. Then, the six-way component force (Fx, Fy, Fz, Mx) of the input vibration is calculated based on the detected value (change in capacitance) of each of the capacitive sensors 18a to 18h by the formula of [Equation 1]. , My, Mz). In addition, in the matrix: A ′, the specific values of a ₁₁ , a ₁₃ , a ₁₅ , a ₁₆ , a ₅₁ , a ₅₃ , a ₅₄ , a ₅₅ , a ₅₆ , a ₆₆ are attached to the suspension bush 10. It is determined according to the characteristics of the vehicle to be set, and is set based on the result of the vibration test or the like.

  The calculation of the component force of vibration using such an arithmetic expression, for example, applies Mx and My to the suspension bush 10 to measure the amount of change in capacitance of each of the capacitive sensors 18a to 18d, It can also be confirmed by comparing the result of simulating the amount of change in capacitance based on the equation of [Equation 2] with respect to the actual measurement value. That is, in the suspension bush 10, the measured value of the change in capacitance of the capacitive sensors 18 a to 18 d with respect to the combined input of Mx and My shown in FIG. The theoretical values from the simulation shown are close. Therefore, if the matrix A is calculated based on the matrix [A ′] of [Equation 2], the input vibration is calculated from the amount of change in capacitance of the capacitive sensors 18a to 18h based on the arithmetic expression of [Equation 1]. It can be said that the magnitude of the input vibration and the input direction can be measured with sufficient accuracy by calculating the six component forces. In FIG. 8, the change in the capacitance of the capacitance sensor 18a is a solid line, the change in the capacitance of the capacitance sensor 18b is a broken line, and the change in the capacitance of the capacitance sensor 18c. The change is indicated by a one-dot chain line, and the change in capacitance of the capacitive sensor 18d is indicated by a two-dot chain line.

  In the suspension bush 10 of the present embodiment having such a sensing mechanism, an external force input to the main rubber elastic body 16 is detected by the capacitive sensor 18. That is, when the main rubber elastic body 16 is elastically deformed by the action of an external force, the electrostatic capacity sensor 18 is elastically deformed by the electrostatic capacity sensor 18. Changes based on the change in the thickness of the dielectric layer 20 and the change in the area of the electrode film 22 due to expansion and contraction. Since the amount of change in capacitance corresponds to the amount of elastic deformation of the main rubber elastic body 16, the external force acting on the main rubber elastic body 16 is obtained based on the change in the capacitance of the capacitance type sensor 18. be able to. In the vehicle to which the suspension bush 10 is mounted, the accelerator and the brake are controlled in accordance with the external force obtained from the detection result of the capacitive sensor 18, thereby preventing side slip (improving running stability) Efficient acceleration and deceleration are realized.

  Further, the capacitance type sensor 18 of the suspension bush 10 has both the dielectric layer 20 and the electrode film 22 formed of an elastic material, and has elasticity that can follow the elastic deformation of the main rubber elastic body 16. ing. Therefore, even if the main rubber elastic body 16 is deformed greatly, sufficient durability is ensured without being damaged by the deformation. In particular, the dielectric layer 20 and the electrode film 22 constituting the capacitance type sensor 18 are both formed of an elastic material that allows a large expansion and contraction deformation of 10% with respect to the initial state in the long side direction. Therefore, sufficient followability to the elastic deformation of the main rubber elastic body 16 is exhibited, and problems such as breakage are avoided.

  Furthermore, since the electrode film 22 is formed by printing with conductive ink in which conductive fillers are dispersed, the elastic electrode film 22 can be easily formed.

  Further, since the capacitive sensor 18 is overlapped and fixed to the axial end surface of the main rubber elastic body 16, local deformation such as bending of the capacitive sensor 18 is caused by the main rubber elastic body 16. It is prevented and durability is improved. Moreover, since the capacitive sensor 18 is fixed to the axial end surface of the main rubber elastic body 16, the capacitive sensor 18 can be easily arranged.

  Further, the capacitive sensor 18 vulcanized and bonded to the axial end surface of the main rubber elastic body 16 is covered with a protective layer 32 formed of an elastic material, and the electrostatic capacitance sensor 18 is exposed to the outside. Is prevented. Therefore, damage to the capacitive sensor 18 due to contact of other members or the like is avoided.

  The capacitance type sensor 18 is disposed so that the opposing direction of the inner shaft member 12 and the outer cylinder member 14 is a long side, and the inner shaft member 12 and the outer cylinder with respect to the main rubber elastic body 16. When a tensile force is applied in the opposite direction of the member 14, the capacitance of the capacitance type sensor 18 changes. As a result, external force (Fx, Fy) acting in the direction perpendicular to the axis, external force (Fz) acting in the axial direction, external force acting in the twisting direction (Mx, My), and external force (Mz) acting in the torsion direction In the cylindrical suspension bush 10 in which the tensile force in the opposing direction of the inner shaft member 12 and the outer cylindrical member 14 acts on the main rubber elastic body 16, the capacitance type is small. The external force in six directions can be effectively detected by the number of sensors 18 provided.

  Further, the capacitive sensor 18a and the capacitive sensor 18b, the capacitive sensor 18c and the capacitive sensor 18d, the capacitive sensor 18e, the capacitive sensor 18f, and the capacitive sensor 18g. And the electrostatic capacity type sensor 18h are arranged with the inner shaft member 12 sandwiched in the radial direction, respectively, and the external force can be efficiently detected with a small number of sensors. Further, the capacitance type sensors 18a and 18b and the capacitance type sensors 18c and 18d, the capacitance type sensors 18e and 18f, and the capacitance type sensors 18g and 18h are arranged so that the radial lines facing each other are orthogonal to each other. By being arranged, the detection accuracy is also improved.

  Further, the capacitive sensor 18a and the capacitive sensor 18g, the capacitive sensor 18b and the capacitive sensor 18h, the capacitive sensor 18c, the capacitive sensor 18e, and the capacitive sensor 18d. And the capacitive sensor 18f are arranged so as to be paired on the tensile deformation side and the compression deformation side in accordance with the input of the external force in the twisting direction. Thereby, the external force in the twisting direction can be detected by the change in the capacitance of the capacitance type sensor 18. In addition, since the capacitive sensor 18 is fixed to the axial end face of the main rubber elastic body 16, the external force in the twisting direction can be detected with high accuracy by the capacitive sensor 18.

  Further, the capacitive sensors 18e, 18g are displaced to one side in the circumferential direction with respect to a radial line (a radial line extending in the left-right direction in FIG. 2) passing through the central axis of the inner shaft member 12. The capacitive sensors 18f and 18h are disposed on the other side in the circumferential direction with respect to a radial line (a radial line extending in the vertical direction in FIG. 2) passing through the central axis of the inner shaft member 12. It is disposed at a displaced position. Thus, when the external force in the circumferential direction is input, the amount of change in capacitance between the capacitance type sensors 18e, 18g and the capacitance type sensors 18f, 18h depending on whether the input external force is clockwise or counterclockwise. Therefore, it becomes possible to detect the external force in the circumferential direction.

  Further, the capacitive sensors 18e to 18h have an inclination angle in the circumferential direction with respect to a plane orthogonal to the axial direction. Therefore, in the capacitive sensors 18e to 18h, the detection accuracy accompanying the increase in the projected area in the axial direction of the electrode film 22 is achieved while ensuring a sufficiently large area of the electrode film 22 and improving the detection accuracy. The decline is suppressed. In other words, the capacitance type sensor 18 increases the projected area in the axial direction and reduces the difference between the lengths of the long side (radial direction) and the short side (circumferential direction). The accuracy decreases and the detection accuracy of external force decreases. Here, by being arranged so as to be inclined in the circumferential direction, anisotropy of detection sensitivity is realized without reducing the area of the electrode film 22, and improvement of detection accuracy is achieved.

  Further, since the capacitive sensor 18 is directly superimposed and fixed on the main rubber elastic body 16, the elastic deformation amount of the main rubber elastic body 16 is linearly elastic. It can be expressed as a deformation amount, and the external force can be detected with high accuracy.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, in the above-described embodiment, external force is detected by the six capacitive sensors 18a to 18h in six directions including two axis perpendicular directions, an axial direction, two twisting directions, and a twisting direction. However, it is also possible to change the number of external forces that can be detected as necessary, in which case the number of capacitive sensors and the position and direction of the capacitive sensors are changed so that the external force can be specified. Just do it.

  In the above embodiment, the capacitance type sensor 18 is fixed to the axial end surface of the main rubber elastic body 16. However, the capacitance type sensor 18 is embedded in the axial middle portion of the main rubber elastic body 16. May be. According to this, the surface of the capacitive sensor 18 is covered with the insulator without providing a special protective layer 32, and exposure to the outside is prevented, so that the durability is improved.

  Further, the protective layer 32 may be omitted, and the capacitive sensor 18 may be fixed to the axial end surface of the main rubber elastic body 16 in a manner that the capacitance sensor 18 is exposed to the outside. Also in this case, since the local deformation such as bending of the capacitive sensor 18 is suppressed by the main rubber elastic body 16, the durability of the capacitive sensor 18 is ensured.

  Moreover, although the example which applied this invention to the suspension bush was shown in the said embodiment, this invention is applicable also to an engine mount, a body mount, a sub-frame mount, etc. Furthermore, the present invention is not only applied to the cylindrical vibration isolator, for example, the first attachment member is fixed to the small diameter side end of the substantially truncated cone-shaped main rubber elastic body, A bowl-shaped vibration isolator having a structure in which the second mounting member is fixed to the end portion on the large diameter side is also applicable. Further, the scope of application of the present invention is not limited to a vibration isolator for automobiles, and can be suitably applied to a vibration isolator used for motorcycles, railway vehicles, industrial vehicles, and the like.

10: suspension bush (vibration isolation device capable of detecting external force), 12: inner shaft member (first mounting member), 14: outer cylinder member (second mounting member), 16: main rubber elastic body, 18: Capacitance type sensor, 20: dielectric layer, 22: electrode film, 32: protective film

Claims (8)

An outer cylinder member as a second attachment member is externally inserted into an inner shaft member as a first attachment member , and a main rubber elastic body is disposed and connected between the inner shaft member and the outer cylinder member. In the vibration isolator
Using a capacitance type sensor in which a pair of electrode films made of a conductive elastic material is provided on both sides of a dielectric layer made of a dielectric elastic material, between the inner shaft member and the outer cylinder member The capacitive sensor is disposed in a state extending in the opposing direction of the inner shaft member and the outer cylinder member, which is the direction of the tensile force acting on the main rubber elastic body when the external force acts .
The vibration isolator capable of detecting an external force, wherein the capacitance type sensor is fixed to an end face in the axial direction of the main rubber elastic body. A pair of the capacitive sensors arranged with the inner shaft member interposed in the radial direction on both end surfaces in the axial direction of the main rubber elastic body, and the inner shaft member disposed in the other radial direction. The anti-vibration device capable of detecting an external force according to claim 1 , wherein the other pair of capacitance type sensors are arranged. The capacitive sensor is disposed at a position separated by a predetermined distance in the axial direction in the main rubber elastic body so as to be paired on the tensile deformation side and the compression deformation side when the external force is input in the twisting direction. The vibration isolator which can detect the external force according to claim 1 or 2 . In the main rubber elastic body, a pair of a position biased on one side in the circumferential direction and a position biased on the other side in the circumferential direction with respect to a radial line passing through the central axis of the inner shaft member are paired. The vibration isolator capable of detecting an external force according to any one of claims 1 to 3 , wherein the capacitance type sensor is disposed. The capacitive sensor is any one of the inner shaft claims with respect to a plane perpendicular to the central axis has an inclination angle in the circumferential direction of the central axis of the inner shaft member of the members 1-3 1 An anti-vibration device capable of detecting the external force described in the item. Wherein together with the capacitive sensor is fixed to the surface of the main rubber elastic body, claim protection layer is formed of an insulating elastic material for covering the electrostatic capacity-type sensor 1 to 5 The vibration isolator which can detect the external force of any one of these. The vibration isolator capable of detecting an external force according to any one of claims 1 to 6 , wherein the pair of electrode films are formed of rubber-based conductive ink. The vibration isolator capable of detecting an external force according to any one of claims 1 to 7 , wherein each of the dielectric layer and the pair of electrode films is formed of an elastic material that is allowed to expand and contract by 10% or more. apparatus.

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