JP5602582B2 - Force sensor - Google Patents

Description

  The present invention relates to a force sensor that detects components in multiple directions of external force and moment acting on a force receiving portion.

  A force sensor is used to detect an external force acting on each part of an industrial robot arm or a medical manipulator. As an example of such a force sensor, a 6-axis force sensor using an optical displacement sensor is disclosed (see Patent Document 1).

  The force sensor includes a support portion, a force receiving portion, and an elastic connecting portion that connects them. Here, the support portion has a cylindrical shape, and reflectors (detection target bodies) are arranged at three positions at intervals of 120 degrees on the cylindrical inner wall portion of the support portion, while the force receiving portion is inside the support portion. In the force receiving portion, three pairs of optical displacement sensors including a light source and a light receiving element are disposed. The light beam emitted from the light source is reflected twice by the reflector and enters the light receiving element. The light receiving element has a light receiving surface divided into four parts, and each outputs a detection signal proportional to the amount of light received.

  When an external force acts on the force receiving portion in a state where the support portion is fixed, the elastic coupling portion is elastically deformed. As a result, the force receiving portion is displaced according to the direction and magnitude of the external force with respect to the support portion. At this time, since the position of the light beam incident on the light receiving surface of the light receiving element changes, the signal detected on each of the four light receiving surfaces is changed. Therefore, the direction and magnitude of the displacement of the reflector, that is, the force receiving portion can be detected by the operation calculation of the detection signal of each light receiving surface.

JP 2005-98964 A

  By the way, in general, a single displacement sensor can detect a displacement with high sensitivity only in components in specific one or two directions, and cannot detect components in other directions. For example, the above-described conventional optical displacement sensor can detect only two components of displacement in the direction parallel to the light receiving surface of the light receiving element, and the component of displacement rotating in the direction perpendicular to the light receiving surface or within the light receiving surface is It cannot be detected. Therefore, when using such a displacement sensor to detect three or more components of an external force including a moment, a plurality of displacement sensors are required, and it is necessary to dispose each at a different position in a different direction. is there. For this reason, in the above example, three optical displacement sensors are used to detect the components of the six axes, that is, the three directions of the external force and the moments in the three directions, and they are arranged 120 degrees apart from each other. ing.

  However, in the conventional force sensor, it is necessary to dispose a plurality of displacement sensors at different positions in different directions, so that the volume of the occupied portion of the displacement sensor increases, resulting in a reduction in size and cost. It was difficult.

  Therefore, an object of the present invention is to provide a force sensor that is reduced in size and cost.

  The present invention includes a support portion, a force receiving portion that is displaced relative to the support portion by the action of an external force, an elastic connection portion that connects the support portion and the force receiving portion, the support portion, and the force receiving portion. And a displacement direction conversion mechanism having a displacement portion that is displaced in a horizontal direction with respect to the support portion by a displacement in a vertical direction of the force receiving portion with respect to the support portion, and each of the displacement direction conversion mechanisms. A detection object provided on the support part side of the displacement part, and a displacement detection element that is supported by the support part so as to face each detection object, and detects the movement of each detection object; It is provided with.

  According to the present invention, since each detection object is arranged on the support part side of the displacement part that is displaced in the horizontal direction, each detection object is arranged in the same direction. And since each displacement detection element is supported by the support part so as to oppose each detection object, each displacement detection element will be arrange | positioned facing the same direction. In this way, by arranging the respective detection objects and the respective displacement detection elements in the same direction, the occupied area can be reduced, so that the force sensor can be reduced in size. Cost reduction of the force sensor can be realized.

It is a perspective view which shows the force sensor which concerns on 1st Embodiment of this invention. It is explanatory drawing which shows the internal structure of the force sensor which concerns on 1st Embodiment of this invention, (a) is a top view of the force sensor in the state which removed the upper cover and the conversion member attachment board, (b) is X-. It is sectional drawing of the force sensor along a Z surface. It is a figure which shows the detailed structure of the displacement direction conversion member of the force sensor which concerns on 1st Embodiment of this invention, (a) is sectional drawing which looked at the displacement direction conversion member from the side, (b) is displacement direction conversion. It is the bottom view which looked at the member from the lower surface. It is a top view which shows the sensor board | substrate of the force sensor which concerns on 1st Embodiment of this invention. It is a perspective view which shows the force sensor which concerns on 2nd Embodiment of this invention. It is explanatory drawing which shows the internal structure of the force sensor which concerns on 2nd Embodiment of this invention, (a) is a top view of the force sensor in the state which removed the upper cover and the conversion member attachment board, (b) is X-. Sectional drawing of the force sensor along Z surface, (c) is a bottom view of the force sensor of the state which removed the lower cover. It is a figure which shows the detailed structure of the displacement direction conversion member of the force sensor which concerns on 2nd Embodiment of this invention, and a scale mounting plate, (a) is sectional drawing which looked at the displacement direction conversion member from the side surface, (b) ) Is a bottom view of the displacement direction conversion member as seen from the bottom surface. It is a top view which shows the sensor board | substrate of the force sensor which concerns on 2nd Embodiment of this invention. It is sectional drawing which looked at the displacement direction conversion member of the force sensor which concerns on 3rd Embodiment of this invention from the side surface. It is a side view of the displacement direction conversion member of the force sensor which concerns on 4th Embodiment of this invention. It is sectional drawing which looked at the displacement direction conversion apparatus of the force sensor which concerns on 5th Embodiment of this invention from the side surface.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a perspective view showing a force sensor according to a first embodiment of the present invention. 2A and 2B are explanatory views showing the internal configuration of the force sensor. FIG. 2A is a plan view of the force sensor with the top cover and the conversion member mounting plate removed, and FIG. It is sectional drawing of the force sensor along a surface.

  The force sensor 100 of the first embodiment is a triaxial force sensor, and can detect Fz (force in the Z direction), Mx (moment about the X direction), and My (moment about the Y direction). It is. Here, the directions of X, Y, and Z are as shown in the drawings.

  As shown in FIG. 1, the force sensor 100 includes a columnar main body 2, a disc-shaped upper lid 4 that covers the upper portion of the main body 2, and a disc-shaped lower lid 1 that covers the lower portion of the main body 2. Yes. 2 (a) and 2 (b), the main body 2 is fixed to the cylindrical member 6 and the upper part of the cylindrical member 6, and a cylindrical conversion member mounting plate having an inner peripheral surface formed in a step shape. 3 is provided. The main body 2 includes a sensor support 5 that is disposed inside the cylindrical member 6 and serves as a columnar support portion having a length shorter than the length of the cylindrical member 6 in the axial direction.

  A sensor substrate 11 is fixed to the upper surface which is one end surface of the sensor support 5. The lower lid 1 is fixed to the lower surface which is the other end surface of the sensor support 5. The outer peripheral surface of the sensor support 5 and the inner peripheral surface of the cylindrical member 6 are connected by a plurality of elastic connecting portions 7a, 7b, and 7c. The sensor support 5, the cylindrical member 6, and the elastic connecting portions 7a, 7b, 7c are integrally formed. Each of the elastic connecting portions 7a, 7b, and 7c is composed of a pair of upper and lower beams whose thickness in the Z direction is thinner than that in the X and Y directions, and has a structure that is small in rigidity and easy to deform only in the Z direction. That is, the second fixing portion A2 as the force receiving portion is displaced by the action of an external force with respect to the first fixing portion A1.

  In the first embodiment, the sensor support 5 and the lower lid 1 as a support portion constitute a first fixing portion A1. Further, the upper lid 4, the conversion member mounting plate 3, and the cylindrical member 6 constitute a second fixing portion A <b> 2 as a force receiving portion. Further, since the first fixing portion A1 and the second fixing portion A2 are connected by the elastic connecting portions 7a, 7b, and 7c, the second fixing portion A2 is in the Z direction with respect to the first fixing portion A1. Displacement, inclination around the X direction, and inclination around the Y direction are easy. The first fixing portion A1 configured as described above is attached to a base (not shown) or the like, and the second fixing portion A2 is attached to a robot arm or manipulator (not shown).

  In the first embodiment, the force sensor 100 includes displacement direction conversion members 10a, 10b, and 10c as displacement direction conversion mechanisms that are arranged in a plurality between the first fixed portion A1 and the second fixed portion A2. I have. Each displacement direction conversion member 10a, 10b, 10c is formed in a substantially Y shape, and is arranged at three positions at intervals of 120 degrees around the central axis L extending in the Z direction of the cylindrical member 6 of the main body 2. . Each displacement direction conversion member 10 a, 10 b, 10 c is attached such that an intermediate end portion 23 protruding in the intermediate horizontal direction is located above the sensor substrate 11.

  Next, the detailed structure and function of each displacement direction conversion member 10a, 10b, 10c is demonstrated using FIG. Since the displacement direction conversion members 10a, 10b, and 10c have the same structure, the displacement direction conversion member 10a will be described. 3A is a cross-sectional view of the displacement direction conversion member as viewed from the side surface, and FIG. 3B is a bottom view of the displacement direction conversion member as viewed from the bottom surface.

  The displacement direction changing member 10a is formed by bending and bonding a plurality of elastic plates 25, 26, and 27, for example, thin plates such as phosphor bronze and stainless steel. More specifically, the displacement direction conversion member 10a has a pair of elastic plates 25 and 26 formed by bending a belt-like plate material into a Z shape. The pair of elastic plates 25 and 26 are arranged mirror-symmetrically on a plane F that is horizontal with respect to the upper surface of the sensor support 5 of the first fixed portion A1.

  The first elastic plate member 25, which is one of the pair of elastic plate members 25, 26, has a flat base end 25a, a flat front end 25b, a base end 25a, and a front end 25b. The link part 25c which is a flat part between. The first elastic plate member 25 includes a base end portion 25a and a link portion 25c that are connected by a first bent portion 25d, and a link portion 25c and a distal end portion 25b that are connected by a second bent portion 25e. It is formed in a Z shape.

  Similarly, the second elastic plate member 26, which is the other elastic plate member of the pair of elastic plate members 25, 26, has a flat plate-like base end portion 26a, a flat plate-like tip end portion 26b, a base end portion 26a, and a tip end. The link part 26c which is a flat part between the part 26b. The second elastic plate member 26 has a base end portion 26a and a link portion 26c connected by a first bent portion 26d, and a link portion 26c and a distal end portion 26b connected by a second bent portion 26e. It is formed in a Z shape.

  The base end portion 25a of the first elastic plate member 25 is fixed to the sensor support 5 of the first fixing portion A1. On the other hand, the base end portion 26a of the second elastic plate member 26 is fixed to the conversion member mounting plate 3 of the second fixing portion A2.

  The displacement direction conversion member 10a is formed in a substantially Y shape by joining the tip portions 25b and 26b of the pair of elastic plates 25 and 26 to each other. The intermediate end portion 23 formed by joining the tip portions of the pair of elastic plates 25 and 26 is sensor-supported by the vertical displacement of the second fixing portion A2 with respect to the sensor support body 5 of the first fixing portion A1. It is a displacement part that is displaced in the horizontal direction with respect to the body 5.

  In the first embodiment, the base end portion 25a of the first elastic plate member 25 of each of the displacement direction changing members 10a, 10b, 10c is attached to and integrated with the annular substrate 24, so that the assembling work is easy. It has become.

  The intermediate end portions 23 of the displacement direction conversion members 10a, 10b, and 10c are all directed toward the central axis L of the cylindrical member 6, and the lower surface of the intermediate end portion 23 (the surface on the support portion side) is detected for detecting displacement. Scales 34a, 34b, and 34c, which are objects, are attached. The scales 34a, 34b, 34c are arranged at the same level in the Z direction.

  In the first embodiment, each of the displacement direction changing members 10a, 10b, and 10c has a third elastic plate member 27 formed by bending a belt-like plate member into a Z shape. The third elastic plate member 27 includes a flat base end 27a, a flat front end 27b, and a link portion 27c that is a flat portion between the base end 27a and the front end 27b. The third elastic plate member 27 includes a base end portion 27a and a link portion 27c that are connected by a first bent portion 27d, and a link portion 27c and a distal end portion 27b that are connected by a second bent portion 27e. It is formed in a Z shape. In the third elastic plate member 27, the intermediate end portion 23 as a displacement portion is provided to maintain a horizontal state with respect to the sensor support 5. The base end portion 27 a of the third elastic plate member 27 is disposed and fixed between the base end portion 25 a of the first elastic plate member 25 and the substrate 24, and the tip end portion 27 b is the tip of the first elastic plate member 25. It is fixed to the surface of the portion 25b on the sensor support 5 side. That is, each scale 34 a, 34 b, 34 c is fixed to the intermediate end portion 23 as a displacement portion via the tip end portion 27 b of the third elastic plate member 27. The link portion 27c of the third elastic plate member 27 is spaced apart from the link portion 25c of the first elastic plate member 25 and is arranged in parallel with the link portion 25c.

  Further, in the first embodiment, the reinforcing ribs 25f, 26f, 26g, and 27f are formed in portions other than the bent portions 25d, 25e, 26d, 26e, 27d, and 27e of the respective elastic plate members 25, 26, and 27. More specifically, the link portions 25c, 26c, 27c and the tip portion 26b are given rigidity by reinforcing ribs 25f, 26f, 26g, 27f formed on both sides by bending in the vertical direction. As described above, since the reinforcing ribs 25f, 26f, 26g, and 27f are provided at the portions other than the bent portions of the elastic plate members 25, 26, and 27, the elastic plate members 25, 26, and 27 are bent portions 25d, 25e, and 26d. , 26e, 27d and 27e can be elastically deformed. Further, since the link portion 26c and the link portion 27c are arranged in parallel, the intermediate end portion 23 as the displacement portion is always parallel to the sensor support 5 (substrate 24) even during elastic deformation. maintain.

  When the external force Fz, the moment Mx, or the moment My is applied to the second fixed portion A2, the second fixed portion A2 is applied to the first fixed portion A1 by the above-described configurations of the displacement direction conversion members 10a, 10b, and 10c. In contrast, it is displaced in the Z direction, tilted around the X direction, or tilted around the Y direction. Accordingly, the base end portions 26a of the displacement direction conversion members 10a, 10b, 10c attached to the second fixing portion A2 are also displaced in the Z direction indicated by the arrow V, respectively. As a result, the bent portions 25d, 25e, 26d, 26e, 27d, and 27e are elastically deformed, and the intermediate end portion 23 is in the XY plane horizontal to the sensor support 5 and extends in the direction ( Displacement in the directions indicated by arrows Ha, Hb, and Hc).

  In this way, the displacement direction conversion members 10a, 10b, and 10c change the direction of displacement of the base end portion 26a that is the detection position with respect to the base end portion 25a, and the scales 34a, 34b, and 34c that are detection target bodies are displaced. It is.

  Next, an external force detection method will be described. FIG. 4 shows the upper surface of the sensor substrate 11. On the sensor substrate 11, one light source 31 (for example, LED) and three light receiving elements 32a, 32b, and 32c (for example, photodiode) that are three displacement detection elements surrounding the light source 31 are integrally formed or mounted. The light receiving elements 32a, 32b, and 32c have a configuration in which a plurality of light receiving surfaces as detection surfaces are arranged in a stripe shape.

On the other hand, the scales 34a, 34b, and 34c shown in FIG. 3 are configured by a diffraction grating including a substrate such as glass and a reflective film such as metal formed on the front surface or the back surface thereof. The scales 34a, 34b, and 34c are arranged so as to face the light receiving elements 32a, 32b, and 32c. The pattern is formed. The arrangement pitch of the light receiving surfaces of the light receiving elements 32a, 32b, and 32c is formed so as to coincide with a quarter cycle of the diffracted light pattern. Accordingly, when the scales 34a, 34b, 34c are displaced in the light receiving surface arrangement direction, the pattern of the diffracted light is also moved accordingly. As a result, a two-phase sinusoidal signal (sin and cos) having a phase difference of 90 degrees is obtained from the plurality of light receiving surfaces, and the scale 34a is obtained by performing an arctangent operation (tan ⁻¹ ) of the obtained signal. , 34b, 34c can be detected.

  As described above, the light receiving elements 32a, 32b and 32c are displaced in the X and Y directions of the scales 34a, 34b and 34c converted from the displacement in the Z direction of the base end portion 26a of the displacement direction converting members 10a, 10b and 10c, respectively. Is detected. From the three signals obtained, Fz, Mx, My, which are three components of the external force, are obtained by calculation.

  As described above, in the first embodiment, the scales 34a, 34b, and 34c are arranged on the lower surface (surface on the support portion side) of the intermediate end portion 23 that is the displacement portion, so that the scales 34a, 34b, and 34c are the same. It will be arranged facing the direction. And since each light receiving element 32a, 32b, 32c is supported by the sensor support body 5 which is a support part so as to oppose each scale 34a, 34b, 34c, each scale 34a, 34b, 34c faces the same direction. Will be placed. In this way, by arranging the scales 34a, 34b, 34c and the light receiving elements 32a, 32b, 32c in the same direction, the occupied area can be reduced. Therefore, the force sensor 100 can be reduced in size, and the cost of the force sensor 100 can be reduced.

[Second Embodiment]
Next, the force sensor 100A according to the second embodiment of the present invention will be described in detail. FIG. 5 is a perspective view showing a force sensor according to the second embodiment of the present invention. 6A and 6B are explanatory views showing the internal structure of the force sensor. FIG. 6A is a plan view of the force sensor with the top cover and the conversion member mounting plate removed, and FIG. It is sectional drawing of the force sensor along a surface. FIG. 6C is a bottom view of the force sensor with the lower lid removed. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The force sensor 100A of the second embodiment is a six-axis force sensor, and is Fx (force in the X direction), Fy (force in the Y direction), Fz (force in the Z direction), Mx (around the X direction). ), My (moment around Y direction), and Mz (moment around Z direction) can be detected. Here, the directions of X, Y, and Z are as shown in the drawings.

  As shown in FIG. 5, the force sensor 100A includes a cylindrical main body 2A, a disk-shaped upper lid 4 that covers the upper portion of the main body 2A, and a disk-shaped lower lid 1 that covers the lower portion of the main body 2A. Yes. The main body 2 </ b> A includes a main body lower part 14 and a main body upper part 15.

  6 (a) and 6 (b), the main body upper portion 15 includes a sensor substrate 11A instead of the sensor substrate 11 in the main body 2 of the first embodiment, and is supported instead of the sensor support body 5. An upper body 17 is provided.

  The main body lower portion 14 is disposed below the cylindrical member 6 serving as the upper portion of the cylinder, the outer peripheral diameter is the same as the outer peripheral diameter of the cylindrical member 6, and the cylindrical member 18 serving as the lower cylindrical portion is disposed inside the cylindrical member 18. A columnar support lower portion 16 fixed to the lower surface of the support upper portion 17.

  The outer peripheral surface of the support lower portion 16 and the inner peripheral surface of the cylindrical member 18 are connected by a plurality of elastic connecting portions 8a, 8b, and 8c. The lower support 16, the cylindrical member 18, and the elastic coupling portions 8 a, 8 b, and 8 c are integrally formed. As shown in FIG. 6 (c), rectangular through holes 12a, 12b, 12c, 13a, 13b, and 13c are formed on both sides of the elastic connecting portions 8a, 8b, and 8c, and the elastic connecting portions 8a, 8b, and 8c are formed. When viewed from the Z direction, it consists of an H-shaped beam with four ends fixed. Each beam has a sufficiently large dimension in the Z direction, and any beam can be easily bent and deformed within the XY plane.

  In the second embodiment, the cylindrical member 18 and the lower lid 1 constitute a first fixing portion A1 '. Further, the support upper part 17 and the support lower part 16 constitute an intermediate part B as a support part. Further, the upper lid 4, the conversion member mounting plate 3, and the cylindrical member 6 constitute a second fixing portion A <b> 2 ′ as a force receiving portion. The first fixed portion A1 'is attached to a base (not shown) or the like, and the second fixed portion A2' is used by being attached to a robot arm or manipulator (not shown).

  Here, the intermediate portion B and the first fixed portion A1 ′ are connected by elastic connecting portions 8a, 8b, and 8c, and the intermediate portion B is displaced in the XY direction and about the Z direction with respect to the first fixed portion A1. Easy to rotate. Further, the second fixed portion A2 ′ and the intermediate portion B are connected by elastic connecting portions 7a, 7b, and 7c. The second fixed portion A2 ′ is displaced in the Z direction with respect to the intermediate portion B, and is rotated around the X direction. Inclination and inclination around the Y direction are easy.

  In the second embodiment, the displacement direction conversion mechanism is the displacement direction conversion members 10a, 10b, and 10c as in the first embodiment, and is provided on the lower surface (surface on the support portion side) of the intermediate end portion 23 as the displacement portion. Scales 34a, 34b, and 34c are attached. Since the displacement direction conversion members 10a, 10b, and 10c have the same configuration and function as those of the first embodiment, detailed description thereof will be omitted below.

  In the second embodiment, the cylindrical member 18 is formed with protruding portions protruding upward at three locations, and scale mounting plates 20a, 20b, 20c extending to the upper side of the sensor substrate 11A are attached to the upper ends thereof.

  FIG. 7 shows the detailed structure of the displacement direction changing members 10a, 10b, 10c and the scale mounting plates 20a, 20b, 20c. 7A is a cross-sectional view of the displacement direction conversion member as viewed from the side, and FIG. 7B is a bottom view of the displacement direction conversion member as viewed from the lower surface. As shown in FIGS. 7A and 7B, scales 35a, 35b, and 35c, which are detection objects for displacement detection, are attached to the lower surfaces of the tips of the scale mounting plates 20a, 20b, and 20c. Yes. The scales 34a, 34b, 34c and the scales 35a, 35b, 35c are arranged at the same level in the Z direction.

  In the second embodiment, the base end portions 25a of the displacement direction conversion members 10a, 10b, and 10c are attached to the support upper portion 17 of the intermediate portion B. Accordingly, the second fixing portion A2 'is displaced in the Z direction with respect to the intermediate portion B by the action of the external force Fz, the moment Mx, or the moment My, and is inclined about the X direction or inclined about the Y direction. Accordingly, the base end portions 26a of the displacement direction conversion members 10a, 10b, 10c attached to the second fixed portion A2 'are also displaced in the Z direction indicated by the arrow V, respectively. As a result, each bent portion is elastically deformed, and the intermediate end portion 23 is displaced in the extending direction (directions indicated by arrows Ha, Hb, Hc) in the XY plane.

  In this way, the displacement direction conversion members 10a, 10b, and 10c change the direction of displacement of the base end portion 26a that is the detection position with respect to the base end portion 25a, thereby displacing the scales 34a, 34b, and 34c that are the objects. .

  The scale attachment plates 20a, 20b, 20c are attached to the cylindrical member 18 of the first fixed portion A1 '. Therefore, it is assumed that the intermediate portion B is displaced in the X direction, displaced in the Y direction, or rotated around the Z direction with respect to the first fixed portion A1 'by the action of the external force Fx, the external force Fy, or the moment Mz. As a result, the scales 35a, 35b, and 35c are displaced relative to the intermediate portion B.

  Next, an external force detection method will be described. FIG. 8 shows a plan view of the sensor substrate 11A. On the sensor substrate 11A, one light source 31 (for example, LED) and six light receiving elements 32a, 32b, 32c, 33a, 33b, 33c (for example, photodiode) surrounding the light source 31 are integrally formed or mounted.

  Since the configuration of each of the light receiving elements 32a, 32b, 32c, 33a, 33b, 33c and the scales 34a, 34b, 34c, 35a, 35b, 35c is the same as that of the first embodiment, the description thereof is omitted. The scales 34a, 34b, 34c, 35a, 35b, and 35c are arranged so as to face the light receiving elements 32a, 32b, 32c, 33a, 33b, and 33c. Each scale 34a, 34b, 34c, 35a, 35b, 35c reflects a divergent light beam generated by the light source 31, and diffracted light that is a bright and dark stripe on each light receiving element 32a, 32b, 32c, 33a, 33b, 33c. Form a pattern.

  As in the first embodiment, the light receiving elements 32a, 32b, and 32c are respectively X and Y of the scales 34a, 34b, and 34c converted from the displacement in the Z direction of the base end portion 26a of the displacement direction conversion members 10a, 10b, and 10c. Detect direction displacement. From the three signals obtained, Fz, Mx, My, which are three components of the external force, are obtained by calculation. Further, the light receiving elements 33a, 33b, and 33c detect displacements of the scales 35a, 35b, and 35c attached to the scale attaching plates 20a, 20b, and 20c, respectively. From the three signals obtained, the other three components of the external force, Fx, Fy, and Mz, are obtained by calculation.

  As described above, in the second embodiment, the scales 34a to 34c and 35a to 35c are arranged on the lower surface (the surface on the support portion side) of the intermediate end portion 23 that is the displacement portion, so that the scales face the same direction. Will be placed. And since each light receiving element 32a-32c, 33a-33c is supported by the intermediate part B which is a support part so that each scale 34a-34c, 35a-35c may be opposed, each scale 34a, 34b, 34c is the same. It will be arranged facing the direction. Thus, by arranging the scales 34a to 34c, 35a to 35c and the light receiving elements 32a to 32c and 33a to 33c in the same direction, the occupied area can be reduced. Therefore, the force sensor 100A can be reduced in size, and thus the cost of the force sensor 100A can be reduced.

[Third Embodiment]
Next, a force sensor according to a third embodiment of the present invention will be described. FIG. 9 is a cross-sectional view of a displacement direction conversion member, which is a displacement direction conversion mechanism of the force sensor according to the third embodiment, viewed from the side. Note that, in the force sensor according to the third embodiment, since the portion excluding the displacement direction conversion member is the same as that of the force sensor according to the first embodiment or the second embodiment, the displacement direction conversion member Only explained. The displacement direction changing members 10a, 10b, and 10c shown in FIG. 9 all have the same structure.

  Each displacement direction changing member 10a, 10b, 10c has a pair of elastic plates made of a first elastic plate 25 bent in a Z shape and a second elastic plate 26 bent in a U shape. ing.

  The first elastic plate member 25 includes a flat plate-like base end portion 25a, a flat plate-like tip end portion 25b, and a link portion 25c that is a flat portion between the base end portion 25a and the tip end portion 25b. The first elastic plate member 25 includes a base end portion 25a and a link portion 25c that are connected by a first bent portion 25d, and a link portion 25c and a distal end portion 25b that are connected by a second bent portion 25e. It is formed in a Z shape.

  On the other hand, the second elastic plate member 26 includes a flat base end portion 26a, a flat plate front end portion 26b, and a link portion 26c that is a flat portion between the base end portion 26a and the front end portion 26b, Consists of. The second elastic plate member 26 has a base end portion 26a and a link portion 26c connected by a first bent portion 26d, and a link portion 26c and a distal end portion 26b connected by a second bent portion 26e. It is formed in a U shape.

  The base end portion 25a of the first elastic plate member 25 is fixed to a substrate 24 fixed to a sensor support as a support portion. On the other hand, the base end portion 26a of the second elastic plate member 26 is fixed to the conversion member mounting plate of the force receiving portion.

  The distal end portion 26b of the second elastic plate member 26 is the base end portion of the first elastic plate member 25 so that the intermediate end portion 23 which is the distal end portion 25b of the first elastic plate member 25 becomes a displacement portion that is displaced in the horizontal direction. It is fixed to a link part 25c which is a flat part between 25a and the tip part 25b. Specifically, the distal end portion 26 b of the second elastic plate member 26 is attached to the middle of the link portion 25 c of the first elastic plate member 25. Note that a third elastic plate member 27 is provided as in the first and second embodiments.

  Further, in the third embodiment, the reinforcing ribs 25f, 25g, 26f, and 27f are formed in portions other than the bent portions 25d, 25e, 26d, 26e, 27d, and 27e of the respective elastic plate members 25, 26, and 27. More specifically, the link portions 25c, 26c, 27c and the tip portion 25b are given rigidity by reinforcing ribs 25f, 25g, 26f, 27f formed by bending the both sides in the vertical direction. Thereby, only each bending part 25d, 25e, 26d, 26e, 27d, 27e can elastically deform each elastic board material 25,26,27. Further, since the link portion 26c and the link portion 27c are arranged in parallel, the intermediate end portion 23 as the displacement portion is always kept parallel to the substrate 24 even during elastic deformation.

  It is assumed that the force receiving portion is displaced in the Z direction relative to the support portion, tilted around the X direction, or tilted around the Y direction by the action of the external force Fz, moment Mx, or moment My. Accordingly, the base end portions 26a of the displacement direction conversion members 10a, 10b, and 10c are also displaced in the Z direction indicated by the arrow V, respectively. As a result, each bent portion is elastically deformed, and the intermediate end portion 23 is displaced in the extending direction (directions indicated by arrows Ha, Hb, Hc) in the XY plane.

  In this way, the displacement direction conversion members 10a, 10b, and 10c change the direction of displacement of the base end portion 26a that is the detection position with respect to the base end portion 25a, and the scales 34a, 34b, and 34c that are the displacement target bodies are displaced. is there.

  In the third embodiment, since the tip end portion 26b of the second elastic plate member 26 is attached to the link portion 25c of the first elastic plate member 25, the displacement whose direction has been changed is the first and second embodiments described above. It is larger than the form, that is, the conversion coefficient can be increased.

[Fourth Embodiment]
Next, a force sensor according to a fourth embodiment of the present invention will be described. FIG. 10 is a side view of a displacement direction conversion member that is a displacement direction conversion mechanism of the force sensor according to the fourth embodiment. In addition, in the force sensor according to the fourth embodiment, since the portion excluding the displacement direction conversion member is the same as that of the force sensor according to the first embodiment or the second embodiment, the displacement direction conversion member Only explained. The displacement direction changing members 10a, 10b, and 10c shown in FIG. 10 all have the same structure.

  Each displacement direction changing member 10a, 10b, 10c has a rotating body 41 connected to the support portion and the force receiving portion via hinge portions 44, 45. If it demonstrates concretely, each displacement direction conversion member 10a, 10b, 10c consists of the rotary body 41, the attachment parts 42 and 43, and the hinge parts 44 and 45, and these are integrally formed.

  In the fourth embodiment, a protruding portion 46 that protrudes horizontally from the rotating body 41 to the support portion is formed as the displacement portion. Scales 34 a, 34 b and 34 c are attached to the lower surface of the protrusion 46. The attachment portion 43 is attached to the sensor support 5 as the support portion shown in FIG. 2 or the support upper portion 17 of the intermediate portion B as the support portion shown in FIG. The attachment portion 42 is attached to the conversion member attachment plate 3 as the force receiving portion shown in FIG. 2 or FIG.

  It is assumed that the force receiving portion is displaced in the Z direction, tilted around the X direction, or tilted around the Y direction with respect to the support portion by the action of the external force Fz, moment Mx, or moment My, and accordingly, the displacement direction conversion member 10a, The mounting portions 42 of 10b and 10c are also displaced in the Z direction indicated by the arrow V. At this time, at the same time as the hinge portions 44 and 45 are elastically deformed, the rotating body 41 rotates with the hinge portion 45 as a fulcrum. As a result, the scales 34a, 34b, and 34c move substantially in parallel in the direction (indicated by the arrows Ha, Hb, and Hc) in which the protruding portion 46 extends substantially in the XY plane.

  In this way, the displacement direction conversion members 10a, 10b, and 10c change the direction of displacement of the attachment portion 42 that is the detection position with respect to the attachment portion 43, and displace the scales 34a, 34b, and 34c, which are the objects.

  The displacement direction conversion member, which is the displacement direction conversion mechanism in the first to fourth embodiments described above, is a method of changing the displacement direction by rotationally displacing the holding member that holds the object for displacement detection. is there. Such means needs to include at least a holding member for the detection target body, a fulcrum serving as a rotation center of the holding member, and a force point that causes an external force to act on the holding member as a moment around the fulcrum. Furthermore, if the direction of the external force is not perpendicular to the straight line connecting the fulcrum and the detection object, preferably the holding member is rotated by the action of the external force and the direction of displacement is changed if parallel.

  For example, in the force sensors of the first to third embodiments shown in FIGS. 3, 7, and 9, the link members 25c and 27c correspond to the holding member of the detection target body, and the link corresponds to the fulcrum. This is a bent portion that connects the portions 25c, 27c and the base end portions 25a, 27a. Further, the bending point that connects the link portion 25c and the link portion 26c corresponds to the power point.

  In the force sensor of the fourth embodiment shown in FIG. 10, the rotating member 41 corresponds to the holding member of the detection target body, the hinge portion 45 corresponds to the fulcrum, and the hinge corresponds to the force point. Part 44.

[Fifth Embodiment]
Next, a force sensor according to a fifth embodiment of the present invention will be described. FIG. 11: is sectional drawing which looked at the displacement direction conversion apparatus which is a displacement direction conversion mechanism of the force sensor which concerns on this 5th Embodiment from the side surface. In the fifth embodiment, all parts except the displacement direction changing device have the same configuration as the force sensor of the first embodiment or the second embodiment. Accordingly, the description of the parts having the same configuration is omitted, and only the displacement direction conversion devices 51a, 51b, and 51c, which are different displacement direction conversion mechanisms from the first embodiment and the second embodiment, will be described.

  In FIG. 11, the displacement direction conversion devices 51a, 51b, and 51c all have the same configuration. Each displacement direction changing device 51 a, 51 b, 51 c includes a container 52, movable members 53, 54, and an attachment member 55. The container 52 is fixed to a support portion (the sensor support body 5 or the intermediate portion B in FIG. 2 or FIG. 6). A space having openings on the upper side and the side is formed in the container 52, and the space is filled with a magnetic fluid 56 that is an incompressible fluid (liquid).

  A movable member 53 is inserted into the opening above the container 52, and the opening above the container 52 is closed. Therefore, the movable member 53 is arranged in a state of penetrating the container 52 so as to be movable in the vertical direction with respect to the support portion. The movable member 53 is fixed to the force receiving portion (the conversion member mounting plate 3 in FIG. 2 or 6) via the mounting member 55.

  Moreover, the movable member 54 which is a displacement part is inserted in the opening of the side of the container 52, and the opening is closed. Therefore, the movable member 54 is disposed in a state of penetrating the container 52 so as to be movable in the horizontal direction with respect to the support portion. A magnet 57 is provided in the space in the container, and attracts the magnetic fluid 56 to prevent outflow.

  The movable member 53 can be displaced in the Z direction indicated by the arrow V while sliding in contact with the inner wall of the container 52, and the movable member 54 can be displaced in the direction perpendicular to the Z direction indicated by the arrows Ha, Hb, Hc. It is.

  If the second fixed portion is displaced in the Z direction relative to the first fixed portion by the action of the external force Fz, the moment Mx, or the moment My, and tilted around the X direction or tilted around the Y direction, the mounting member 55 The movable member 53 is also displaced in the Z direction indicated by the arrow V. Accordingly, the magnetic fluid 56 flows in the container 52 due to the displacement of the movable member 53, and the movable member 54 is displaced by the pressure of the magnetic fluid 56. Therefore, the scales 34a, 34b, 34c are in the XY plane and are movable members. 54 is displaced in the extending direction (directions indicated by arrows Ha, Hb, Hc). In this way, the direction of displacement is converted.

  As mentioned above, although this invention was demonstrated based on the said 1st-5th embodiment, this invention is not limited to this.

  In any of the first to fifth embodiments, a circuit for signal detection or calculation can be integrally formed or mounted on the sensor substrates 11 and 11A.

  In the first to fifth embodiments, a light receiving element is used as the displacement detection element and a scale in which a reflective diffraction grating is formed as the detection target. However, even if other detection elements are used, the displacement is detected based on the same principle. can do. For example, both the displacement detection element and the detection object can be formed as a striped electrode pattern, and the displacement can be detected from a change in capacitance generated therebetween. In addition, a magnetic sensor array (for example, a Hall element or a magnetoresistive element) is used as the displacement detection element, and a patterned magnetic flux generating means (magnet) is used as the detection target, so that the displacement can be detected from a change in the magnetic flux density distribution.

  All of them are composed of a plurality of detection surfaces in which displacement detection elements are arranged in one direction, and are obtained by displacing the distribution of physical quantities (light flux, electric field, magnetic flux, etc.) formed by the detection object in the arrangement direction of the detection surfaces. In this method, the amount of displacement of the detection object is detected from a sine wave signal. Such a method is effective in that the detection resolution can be increased regardless of the displacement detection range by reducing the arrangement pitch of the detection surfaces.

  Further, the displacement direction conversion members 10a, 10b, and 10c detect displacement in the Z direction with respect to the base end portion 25a at each base end portion 26a. In order to detect the inclinations of the second fixing portions A2 and A2 'due to the actions of the moments Mx and My with high accuracy, it is preferable that these three attachment positions as detection positions are separated from each other.

  On the other hand, the displacement whose direction has been changed is detected by the scales 34a to 34c. Therefore, in order to detect the displacement of a plurality of detection positions using a single light source in common as in the above embodiment and to mount all of the plurality of light receiving elements on the same substrate, the scales 34a to 34c are brought close to each other. It is preferable to install them. That is, the displacement direction conversion members 10a, 10b, and 10c are such that the interval between the intermediate end portions 23 provided with the scales 34a, 34b, and 34c is smaller than the interval between the base end portions 26a and the interval between the base end portions 25a. It is desirable to have a proper shape and arrangement. In this respect, it is desirable that the base end portions 25a, 26a of the Y-shaped displacement direction changing members 10a, 10b, 10c are all directed outward and the intermediate end portions 23 are all directed inward as in the above embodiment. It is an example.

  On the other hand, when it is particularly necessary to reduce the outer diameter of the force sensor, it is desirable that the displacement direction conversion members 10a, 10b, and 10c have a shape and an arrangement in which each base end portion 26a faces inward.

DESCRIPTION OF SYMBOLS 3 ... Conversion member mounting plate, 5 ... Sensor support body, 6 ... Cylindrical member, 7a, 7b, 7c ... Elastic connection part, 10a, 10b, 10c ... Displacement direction conversion member, 11, 11A ... Sensor substrate, 17 ... Support body Upper part, 23 ... intermediate end part, 25 ... first elastic plate member, 25a ... base end part, 25b ... tip part, 25c ... link part, 25d ... first bent part, 25e ... second bent part, 25f ... Reinforcement rib, 26 ... second elastic plate material, 26a ... base end portion, 26b ... tip portion, 26c ... link portion, 26d ... first bent portion, 26e ... second bent portion, 26f ... reinforcement rib, 31 ... Light source, 32a, 32b, 32c ... light receiving element, 34a, 34b, 34c ... scale, 100, 100A ... force sensor, A1, A1 '... first fixing part, A2, A2' ... second fixing part, B ... Middle part

Claims (6)

A support part;
A force receiving portion that is displaced with respect to the support portion by the action of an external force;
An elastic connecting part for connecting the support part and the force receiving part;
A displacement direction conversion mechanism having a plurality of displacement portions arranged between the support portion and the force receiving portion and displaced in a horizontal direction with respect to the support portion by a displacement of the force receiving portion in a vertical direction with respect to the support portion. When,
A detection object provided on the support part side of the displacement part of each displacement direction conversion mechanism;
A force sensor comprising: a displacement detection element that is supported by the support portion so as to face each detection target body and detects the movement of each detection target body. Each of the displacement direction conversion mechanisms has a pair of elastic plates that are bent in a Z-shape and are arranged in mirror symmetry with respect to a horizontal plane with respect to the support portion.
A base end portion of one elastic plate member of the pair of elastic plate members is fixed to the support portion, and a base end portion of the other elastic plate member of the pair of elastic plate members is fixed to the force receiving portion,
The force sensor according to claim 1, wherein the displacement portions are formed by joining tip portions of the pair of elastic plates. Each of the displacement direction converting mechanisms has a pair of elastic plates made of a first elastic plate bent into a Z shape and a second elastic plate bent into a U shape,
A base end portion of the first elastic plate member is fixed to the support portion; a base end portion of the second elastic plate member is fixed to the force receiving portion;
The distal end portion of the second elastic plate member is fixed to a flat portion between the base end portion and the distal end portion of the first elastic plate member so that the distal end portion of the first elastic plate member becomes the displacement portion. The force sensor according to claim 1, wherein the force sensor is provided.   4. The force sensor according to claim 2, wherein a reinforcing rib is formed on each of the pair of elastic plates at a portion other than the bent portion. 5. Each displacement direction conversion mechanism has a rotating body connected to the support part and the force receiving part via a hinge part,
The force sensor according to claim 1, wherein a projecting portion that projects horizontally from the rotating body to the support portion is formed as the displacement portion. Each displacement direction conversion mechanism is
A container fixed to the support and filled with a liquid;
A movable member fixed to the force receiving portion and arranged in a state penetrating the container so as to be movable in a vertical direction with respect to the support portion,
2. The force sense according to claim 1, wherein the displacement part is arranged in a state of penetrating the container so as to be movable in a horizontal direction with respect to the support part by a pressure of a liquid inside the container. Sensor.

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