Sensor unit

Abstract

A sensor unit (10) comprises: a rod (20) that extends along a first axis (L1); a support part (16) that movably supports the rod (20) in the direction of the first axis (L1); a first return mechanism (24) that returns the position of the rod (20) in the direction of the first axis (L1) to the initial position; a ball joint (36) that is provided at the tip of the rod (20); a sensor module (12) that is attached to the ball joint (36); and a second return mechanism (26) that restricts the rotation range while returning the sensor module (12) to the initial posture.

Description

Sensor unit

[0001] The present disclosure relates to a sensor unit provided with a swing mechanism.

[0002] In order to bring the sensor module into contact with the measurement object at an appropriate angle, a sensor unit provided with a swing mechanism is used (for example, Japanese Unexamined Patent Application Publication No. 2020-134529).

[0003] In the sensor unit, further improvement in the followability with respect to the measurement object is required. However, when attempting to improve the followability of the sensor module with respect to the measurement object, a problem occurs in that the wiring connected to the sensor module is likely to be disconnected.

[0004] An object of the present disclosure is to solve the above-described problems.

[0005] One aspect of the present disclosure includes a rod extending along a first axis, a support portion that supports the rod movably in the direction of the first axis, a first return mechanism that returns the position of the rod in the direction of the first axis to an initial position, a ball joint provided at the tip of the rod, a sensor module attached to the ball joint and swingable about the ball joint, and a second return mechanism connected to the rod and the sensor module that returns the posture of the sensor module to an initial posture. The second return mechanism has a first end portion connected to the rod so that the circumferential position with respect to the first axis does not shift, and a second end portion connected to the sensor module so that the circumferential position with respect to the first axis does not shift. It is a sensor unit.

[0006] The sensor unit of the present disclosure can prevent disconnection of the connection wiring of the sensor module while improving the followability of the sensor module with respect to the measurement object.

[0007] Figure 1A is a perspective view of the sensor unit according to the first embodiment, and Figure 1B is a perspective view of the sensor unit in Figure 1A with the bellows removed. Figure 2 is a perspective view of the sensor unit in Figure 1B disassembled into its components. Figure 3 is a cross-sectional view along the line III-III in Figure 1A. Figure 4A is a perspective view of the second spring in Figure 2, and Figure 4B is a perspective view of the rod in Figure 2. Figure 5 is a perspective view of the sensor module in Figure 2. Figure 6 is a cross-sectional view illustrating the operation of the sensor unit in Figure 1A. Figure 7A is a perspective view of the sensor unit according to the second embodiment, viewed from diagonally above, and Figure 7B is a perspective view of the sensor unit in Figure 7A, viewed from diagonally below. Figure 8 is a partially cutaway cross-sectional view of the sensor unit in Figure 7A, with a portion cut out along the line VIII-VIII. Figure 9A is an explanatory diagram showing an example of use in which the sensor unit of Figure 7A is attached to a transport robot that transports steel plates to a press machine, and Figure 9B is an explanatory diagram showing an example of detecting two steel plates being picked up at once using the sensor unit of Figure 7A. Figure 10 is a cross-sectional view of the sensor unit according to the third embodiment. Figure 11 is a cross-sectional view of the sensor unit according to the fourth embodiment. Figure 12 is a cross-sectional view of the sensor unit according to the fifth embodiment. Figure 13 is a cross-sectional view of the sensor unit according to the sixth embodiment. Figure 14 is a cross-sectional view of the sensor unit according to the seventh embodiment.

[0008] (First Embodiment) As shown in Figures 1A and 1B, the sensor unit 10 according to this embodiment has a structure in which a sensor module 12 equipped with a sensor is supported by a support portion 16 via a support mechanism 14. The support mechanism 14 is expandable and retractable and swingable. The support mechanism 14 is covered by a bellows 18 made of, for example, a bellows-shaped rubber cover.

[0009] In this embodiment, the sensor unit 10 allows the sensor module 12 to undergo displacement in the first axial direction, such as moving closer to or further away from the support portion 16, as well as tilting and oscillating displacements and rotational displacements in the circumferential direction. This allows the sensor module 12 to contact the workpiece W, which is the object to be measured, from an appropriate direction. The sensor module 12 is not particularly limited, but examples include an electromagnetic sensor, an eddy current sensor, a contact-type displacement sensor, an optical sensor, an ultrasonic sensor, or a temperature sensor (contact type). The sensor module 12 may also be a prober equipped with multiple electrodes and a microprobe that applies a test signal to a semiconductor chip. In the following description, an electromagnetic sensor equipped with an E-type magnetic core 12a and a coil 12b, as shown in Figure 3, is given as an example of the sensor module 12, but this embodiment is not limited to this.

[0010] In the following description, the terms first axis L1 and second axis L2 are used to clarify the arrangement of the parts of the sensor unit 10. As shown in Figure 2, the first axis L1 coincides with the center line of the support part 16. The direction along the first axis L1 is also called the first axis direction. In the first axis direction, the direction from the support part 16 toward the sensor module 12 is called the tip direction, and the opposite direction is called the base direction. The second axis L2 is the center line of the sensor module 12. The direction along the second axis L2 is also called the second axis direction. Due to the oscillation of the sensor module 12, the second axis L2 is tilted with respect to the first axis L1, but in the initial position when the sensor module 12 is not in contact with the workpiece W, the second axis L2 is coaxial with the first axis L1.

[0011] As shown in Figures 2 and 3, the sensor unit 10 includes a support portion 16, a rod 20, a pivot portion 22, a sensor module 12, a first return mechanism 24, and a second return mechanism 26. The rod 20 is supported by the support portion 16 so as to be displaceable in the first axial direction by a cylinder 30 which constitutes part of a guide mechanism 28 formed inside the support portion 16. The first return mechanism 24 is a member that returns the rod 20 to its initial position in the first axial direction. In this embodiment, the first return mechanism 24 is composed of a first spring 32. The sensor module 12 is pivotably connected to the rod 20 by a ball joint 36 which is composed of the pivot portion 22 and a ball receiving portion 34 of the sensor module 12. The second return mechanism 26 is a member that returns the orientation of the sensor module 12 to its initial orientation. In this embodiment, the second return mechanism 26 is composed of a second spring 38.

[0012] The support portion 16 is formed in a cylindrical shape extending in the direction of the first axis. Inside the support portion 16, a cylinder chamber 40 is formed, extending along the first axis L1. The cylinder chamber 40 is a hole with a circular cross-section perpendicular to the first axis L1, opening at the tip and defined at the base end by a base end wall 42. The inner diameter of the cylinder chamber 40 is larger than the outer diameter of the rod body portion 46 of the rod 20. The cylinder chamber 40 houses the rod 20 and the first spring 32.

[0013] The base end wall 42 is located at the base end of the support portion 16. A rod insertion hole 44 is formed in the center of the base end wall 42, penetrating through the first axis L1. The rod body portion 46 of the rod 20 is inserted through the rod insertion hole 44. The rod insertion hole 44, when viewed from the direction of the first axis, has an arc-shaped portion 44a extending along a predetermined radius from the first axis L1, and a notched surface 44b formed to be closer to the first axis L1 than the arc-shaped portion 44a. The notched surface 44b is a plane parallel to the first axis direction and, by contacting the second notched surface 48 of the rod body portion 46 (described later), restricts the rotation of the rod body portion 46 about the first axis L1.

[0014] The rod 20 extends long in the first axial direction. The rod 20 has a rod body portion 46, an enlarged diameter portion 50, a pivot mounting portion 52, and a first through hole 54. The first through hole 54 extends from the tip to the base end along the first axis L1 of the rod 20. A first screw structure 56 is formed on the base end side of the first through hole 54, and a second screw structure 58 is formed on the tip end side.

[0015] The rod body portion 46 is formed in the range from the base end in the first axial direction to the enlarged diameter portion 50. The rod body portion 46 is formed in a substantially cylindrical shape. The outer diameter of the rod body portion 46 is smaller than the inner diameter of the cylinder chamber 40 of the support portion 16. Therefore, a gap capable of accommodating the first spring 32 is formed between the outer circumferential surface of the rod body portion 46 and the inner circumferential surface of the cylinder chamber 40. In addition, a second notched surface 48 is formed in a part of the rod body portion 46 near the base end, by flatly cutting out a part of the cylindrical outer circumferential surface. The second notched surface 48 is composed of a plane parallel to the first axial direction and prevents rotational displacement of the rod 20 in the circumferential direction by making surface contact with the notched surface 44b of the rod insertion hole 44.

[0016] A retaining member 60 is attached to the base end of the rod body 46. The retaining member 60 is attached to the rod body 46 by screwing it into the first threaded structure 56 at the base end of the first through hole 54. The retaining member 60 has an outer diameter larger than the rod insertion hole 44 of the support part 16 and is configured so that it cannot be inserted through the rod insertion hole 44. The retaining member 60 prevents the rod 20 from being pulled out toward the tip by catching on the base end wall 42. A third through hole 60a is formed in the retaining member 60, passing through along the first axis L1. Connection wiring (not shown) for the sensor module 12 is placed in the third through hole 60a.

[0017] The enlarged diameter portion 50 is located between the rod body portion 46 and the pivot mounting portion 52 in the first axial direction. In this embodiment, the enlarged diameter portion 50 is located closer to the tip than the center of the rod body portion 46 in the first axial direction. The enlarged diameter portion 50 has a larger outer diameter than the rod body portion 46. The enlarged diameter portion 50 has an outer diameter approximately the same as the inner diameter of the cylinder chamber 40 and is displaced in the first axial direction while sliding against the inner circumferential surface of the cylinder chamber 40. The cylinder 30 includes the enlarged diameter portion 50, the cylinder chamber 40, and the rod insertion hole 44. The cylinder 30 guides the displacement direction of the rod 20 in the first axial direction.

[0018] The enlarged diameter portion 50 closes the gap between the cylinder chamber 40 and the rod body portion 46. The cylinder chamber 40 between the enlarged diameter portion 50 and the base end wall 42 houses the first spring 32. The first spring 32 is, for example, a compression coil spring and generates elastic force due to the displacement of the sensor module 12 toward the base end. The elastic force of the first spring 32 is transmitted to the rod 20 via the enlarged diameter portion 50, returning the rod 20 to its initial position in the first axial direction.

[0019] As shown in Figure 4B, the enlarged diameter portion 50 has a first contact surface 62 and a first cylindrical portion 64 formed on its tip side. The first contact surface 62 is the portion that contacts the first end 38a of the second spring 38 and is composed of a plane perpendicular to the first axial direction. The first cylindrical portion 64 protrudes a short, annular shape from the inner diameter side portion of the enlarged diameter portion 50 in the first axial direction. The outer surface 64a of the first cylindrical portion 64 is composed of a curved surface parallel to the first axial direction. The outer surface 64a of the first cylindrical portion 64 supports the vicinity of the first end 38a of the second spring 38 from the inner diameter side, thereby supporting the vicinity of the first end 38a of the second spring 38 parallel to the first axial direction.

[0020] Furthermore, a first notch 66 is formed in the first cylindrical portion 64. The first notch 66 is a portion of the first cylindrical portion 64 that has been cut out in a groove shape in the radial direction. The first notch 66 engages with the first bent portion 38b of the first end 38a of the second spring 38, thereby holding the first end 38a of the second spring 38 so as not to rotate relative to the rod 20.

[0021] The pivot mounting portion 52 is a cylindrical portion that extends a short distance toward the tip from the enlarged diameter portion 50. The outer diameter of the pivot mounting portion 52 is smaller than the outer diameter of the enlarged diameter portion 50. A second screw structure 58 is formed in the first through hole 54 on the inner part of the pivot mounting portion 52. The second screw structure 58 screws into the pivot portion 22 to fix the pivot portion 22 to the rod 20.

[0022] As shown in Figures 2 and 3, the pivot portion 22 comprises a threaded portion 68, a rod-shaped portion 70, a spherical portion 72, and a second through-hole 74. The second through-hole 74 extends in the first axial direction along the center of the pivot portion 22 and penetrates the pivot portion 22. The second through-hole 74 communicates with the first through-hole 54 and accommodates the connection wiring of the sensor module 12.

[0023] The threaded portion 68 is located on the base end side of the pivot portion 22 and has a screw groove on its outer circumference that engages with the second screw structure 58. The threaded portion 68 has a locking portion formed at its tip, which has an outer diameter larger than that of the first through hole 54. The locking portion abuts against the pivot mounting portion 52, thereby positioning the pivot portion 22 relative to the rod 20. The pivot portion 22 is fixed to the rod 20 through the threaded portion 68 and displaces integrally with the rod 20. The pivot portion 22 may be formed integrally with the rod 20.

[0024] The rod-shaped portion 70 is a rod-shaped extension from the tip side of the threaded portion 68. The rod-shaped portion 70 is formed in a cylindrical shape. The tip of the rod-shaped portion 70 is integrally connected to the spherical portion 72. The outer surface of the spherical portion 72 is formed by a sphere. The tip of the spherical portion 72 is formed by an end face 72a perpendicular to the first axis L1. A second through hole 74 opens at the tip of the spherical portion 72.

[0025] The sensor module 12 has a sensor body 76 and a ball receiving portion 34. In this embodiment, the sensor body 76 is formed in a cylindrical shape extending along the second axis L2. A contact surface 78 that contacts the workpiece W is formed at the tip of the sensor body 76. The contact surface 78 is formed by a plane perpendicular to the second axis L2. The sensor body 76 of this embodiment has a magnetic core 12a and a coil 12b. The magnetic core 12a has an inner circumferential core 12c and an outer circumferential core 12d. The magnetic core 12a is formed of a ferromagnetic material such as soft iron, silicon steel, or permalloy. The inner circumferential core 12c is located at the radial center of the sensor body 76 and extends in a rod shape along the second axis L2. The base end portion of the inner circumferential core 12c bulges radially outward and contacts the outer circumferential core 12d. Furthermore, a wiring hole 12e is formed at the base end of the inner core 12c for passing wiring extending from the coil 12b.

[0026] The outer core 12d has a cylindrical shape and is positioned to surround the outside of the inner core 12c. The outer core 12d is spaced apart from the inner core 12c except for its base end. A coil 12b is positioned between the outer core 12d and the inner core 12c. The coil 12b is wound around the outer circumference of the inner core 12c and generates a magnetic field in the direction of the second axis L2.

[0027] The ball receiving portion 34 is located at the base end of the sensor body portion 76. The ball receiving portion 34 comprises a cylindrical portion 80, a pivot housing hole 82, a sliding ring 84, and a lock nut 86. The cylindrical portion 80 is integrally connected to the inner circumferential core 12c and protrudes cylindrically from the base end of the inner circumferential core 12c toward the base end along the second axis L2. A third screw structure 88 is formed on the outer circumferential surface of the cylindrical portion 80. A lock nut 86 is fastened to the third screw structure 88. The pivot housing hole 82 is a hole formed on the inner circumferential side of the cylindrical portion 80. The pivot housing hole 82 accommodates the spherical portion 72 of the pivot portion 22. The pivot housing hole 82 has a first sliding surface 82a that is formed to decrease in diameter toward the tip. The first sliding surface 82a abuts against the spherical portion 72 from the tip side.

[0028] The sliding ring 84 is formed in a ring shape and has a tapered hole 84a at its center through which the rod-shaped portion 70 of the pivot portion 22 passes. The tapered hole 84a is funnel-shaped so that its inner diameter increases towards the base end. The sensor module 12 can swing within the range of the inclination angle of the tapered hole 84a. A second sliding surface 84b is formed on the tip side of the sliding ring 84, which contacts the spherical portion 72 of the pivot portion 22. The second sliding surface 84b is formed of a sphere. The second sliding surface 84b holds the spherical portion 72 by contacting it from the base end side.

[0029] The lock nut 86 is attached to the third threaded structure 88 of the cylindrical portion 80. The lock nut 86 covers the base end of the sliding ring 84. By tightening the lock nut 86, the sliding ring 84 is biased toward the base end, and the spherical portion 72 of the pivot portion 22 is held in place by being sandwiched between the sensor body portion 76 and the sliding ring 84. As a result, the sensor module 12 is connected to the rod 20 so as to be able to swing around the spherical portion 72.

[0030] As shown in Figure 5, a second contact surface 90 and a second cylindrical portion 92 are formed on the base end side of the lock nut 86. The second contact surface 90 is the portion that contacts the second end portion 38c (see Figure 4A) of the second spring 38. The second contact surface 90 is formed by a plane perpendicular to the second axis L2. The second cylindrical portion 92 is a short, annular projection that protrudes from the inner diameter portion of the lock nut 86 toward the base end. The outer surface 92a of the second cylindrical portion 92 is parallel to the second axis L2. The outer diameter of the second cylindrical portion 92 is approximately the same as the inner diameter of the second spring 38.

[0031] Furthermore, a second notch 92b is formed in the second cylindrical portion 92. The second notch 92b is a portion of the second cylindrical portion 92 that has been cut out in a groove shape in the radial direction. The second notch 92b engages with the second bent portion 38d (see Figure 4A) of the tip portion (second end portion 38c) of the second spring 38, thereby holding the second end portion 38c of the second spring 38 in a non-rotatable manner relative to the sensor module 12.

[0032] Furthermore, the inner surface 92c of the second cylindrical portion 92 is formed by a conical surface inclined with respect to the second axis L2. The inner surface 92c is flush with the inner circumferential surface of the tapered hole 84a of the sliding ring 84.

[0033] As shown in Figure 3, the second contact surface 90 supports the second end 38c of the second spring 38 so that it is perpendicular to the second axis L2, and the second cylindrical portion 92 supports the vicinity of the second end 38c of the second spring 38 from the inner diameter side. As a result, the vicinity of the second end 38c of the second spring 38 is held parallel to the second axis L2 of the sensor module 12.

[0034] The second spring 38 is positioned between the enlarged diameter portion 50 of the rod 20 and the lock nut 86 of the sensor module 12. As shown in Figure 4A, the second spring 38 has a shape that extends in a coil shape along its centerline with a constant diameter. The first end portion 38a, located on the base end side of the second spring 38, has a first end face 38e that is cut perpendicular to the centerline of the second spring 38. The first end face 38e makes surface contact with the first contact surface 62 of the enlarged diameter portion 50 of the rod 20. The first end portion 38a has a first bent portion 38b that is bent inward. The second end portion 38c, located on the tip side of the second spring 38, has a second end face 38f that is cut perpendicular to the centerline of the second spring 38. The second end face 38f makes surface contact with the second contact surface 90 of the lock nut 86. The second end portion 38c also has a second bent portion 38d that is bent inward.

[0035] The sensor unit 10 of this embodiment is configured as described above. The operation of the sensor unit 10 will be described below.

[0036] The sensor unit 10 in this embodiment is, for example, an electromagnetic sensor, and as shown in Figure 6, is used to detect the thickness and number of workpieces W such as steel plates 120.

[0037] The steel plate 120, which is attracted to the magnetic gripper 118 (see Figure 9A), bends due to its own weight as shown in the figure. The detection result of the electromagnetic sensor is sensitive to the distance from the steel plate 120. Therefore, the sensor unit 10 is required to bring the contact surface 78 of the sensor module 12 into contact with the curved surface 120a of the workpiece W. In this embodiment, when the sensor module 12 of the sensor unit 10 is pressed against the steel plate 120, the sensor module 12 swings so as to tilt according to the inclination of the surface 120a of the steel plate 120. Furthermore, the sensor unit 10 enables displacement of the sensor module 12 in the first axial direction by the displacement of the sensor module 12 in the first axial direction. As a result, the sensor unit 10 can reliably bring the sensor module 12 into contact with the surface 120a of the curved steel plate 120, and accurately detect the thickness and number of the attracted steel plates 120.

[0038] Furthermore, when the sensor module 12 is lifted upward and separated from the steel plate 120, the rod 20 returns to its initial position in the first axial direction by the first spring 32. Also, the sensor module 12 returns to its initial position by the second spring 38, and the second axis L2 of the sensor module 12 aligns with the first axis L1 of the rod 20. In addition, the torsion of the sensor module 12 is eliminated when its rotational displacement returns to a predetermined initial angle. This prevents twisting and breakage of the wiring due to the accumulation of rotational displacement of the sensor module 12.

[0039] (Second Embodiment) As shown in Figures 7A, 7B, and 8, the sensor unit 10A of this embodiment further includes a display module 94 connected to the base end of the support portion 16. In the sensor unit 10A of this embodiment, components similar to those in the sensor unit 10 described with reference to Figures 1A to 5 are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0040] As shown in Figures 7A, 7B, and 8, the display module 94 has a housing 96 shaped like a rectangular parallelepiped with one side cut out by a bevel 96c. A connecting cylinder 98 is formed at the bottom 96a of the housing 96, covering the outer circumference of the support portion 16. Inside the connecting cylinder 98, a connecting hole 100 is formed, extending in the first axial direction and communicating with the inside of the housing 96. The inner diameter of the connecting hole 100 is formed to be approximately the same as the outer diameter of the support portion 16, and the support portion 16 is housed inside the connecting hole 100. In this embodiment, an annular packing housing groove 102 and a packing 104 housed in the packing housing groove 102 are provided on the outer circumference of the support portion 16. The packing 104 seals the gap between the inner surface of the connecting hole 100 and the outer surface of the support portion 16, thereby preventing water and dust from entering the inside of the housing 96.

[0041] The housing 96 has a housing space 106 inside that allows displacement of the base end of the rod 20. The connection wiring of the sensor module 12 reaches the inside of the housing space 106 via the first through hole 54, the second through hole 74, and the third through hole 60a. The connection wiring is connected to a circuit board (not shown) housed inside the housing 96.

[0042] As shown in Figure 7A, a connector 108 for connecting wiring from external devices is provided on the upper end surface 96b of the housing 96. A display unit 110 and an operation unit 112 are provided on the slanted surface 96c of the housing 96. The display unit 110 is made of, for example, an LCD. The display unit 110 is mounted on a circuit board (not shown). The circuit board is equipped with a control circuit that outputs a drive signal to the sensor module 12 and processes the detection signal from the sensor module 12. The control circuit converts the measurement result (detection result) of the sensor module 12 into a value such as the number of steel plates 120 being held and displays it on the display unit 110. The control circuit also displays various setting values ​​such as measurement conditions on the display unit 110. The operation unit 112 is provided with a number of operation buttons. The operation unit 112 accepts input from the user, such as measurement conditions.

[0043] As described above, the sensor unit 10A of the present embodiment can integrate a control circuit, a display unit 110, an operation unit 112, and a sensor module 12. Thereby, the device configuration can be miniaturized and the operability can be improved.

[0044] As shown in FIGS. 9A and 9B, the sensor unit 10A of the present embodiment is used by being attached to a transfer robot 114 for carrying a steel plate 120, which is an example of a workpiece W, into and out of a press device (not shown). The transfer robot 114 includes a magnet gripper 118 that attracts the steel plate 120 by magnetic force at the tip of a robot arm 116. The sensor unit 10A is attached to the robot arm 116 adjacent to the magnet gripper 118. When the workpiece W is attracted by the magnet gripper 118, the sensor unit 10A of the present embodiment abuts against the workpiece W. Further, the sensor module 12 abuts in a direction such that the second axis L2 of the sensor module 12 is substantially perpendicular to the surface 120a of the workpiece W by performing displacement in the first axis direction and swinging with respect to the first axis L1.

[0045] The sensor unit 10A applies a voltage to the coil 12b of the sensor module 12 to magnetize the workpiece W. Due to the inductance corresponding to the thickness of the workpiece W, the coil current rises with a delay with respect to the voltage application to the coil 12b (see FIG. 8) of the sensor module 12. By detecting this delay of the coil current, the thickness and number of sheets of the workpiece W are detected. Note that the above description does not limit the operation of the sensor module 12, and a method of detecting the influence of eddy currents on an alternating magnetic field or the like may be used. The sensor unit 10A can detect, for example, the double-sheet condition of the steel plate 120 as shown in FIG. 9B, which may damage the press die.

[0046] (Third Embodiment) As shown in FIG. 10, the sensor unit 10B of the present embodiment includes a pair of sensor units 10. Since the configuration of each sensor unit 10 is the same as that of the sensor unit 10 described while referring to FIGS. 1A to 5, a detailed description thereof will be omitted. In the sensor unit 10B of the present embodiment, one sensor unit 10 is disposed on the surface 120a side of the plate-shaped workpiece W1 (for example, the steel plate 120), and the other sensor unit 10 is disposed on the back surface 120b side of the plate-shaped workpiece W1. The pair of sensor units 10 are arranged such that the sensor modules 12 face each other with the plate-shaped workpiece W1 interposed therebetween.

[0047] In the present embodiment, the coil 12b of the sensor module 12 of one sensor unit 10 constitutes an exciting coil, and the coil 12b of the sensor module 12 of the other sensor unit 10 constitutes a pickup coil. When a magnetic force for excitation is generated from the sensor module 12 of one sensor unit 10, a magnetic field corresponding to the thickness of the plate-shaped workpiece W1 passes through the plate-shaped workpiece W1, and a detection signal is output from the sensor module 12 of the other sensor unit 10. Thereby, the sensor unit 10B of the present embodiment can detect the thickness of the plate-shaped workpiece W1 based on the detection signal corresponding to the magnetic flux passing through the plate-shaped workpiece W1. Since the pair of sensor units 10 can follow the surface 120a of the plate-shaped workpiece W1 even when the plate-shaped workpiece W1 is bent, the thickness of the plate-shaped workpiece W1 can be accurately detected.

[0048] Note that the sensor module 12 of the present embodiment is not limited to the coil 12b (electromagnetic coil). The sensor unit 10B may be configured as an optical transmission sensor with the sensor module 12 of one sensor unit 10 as a light emitting device and the sensor module 12 of the other sensor unit 10 as a light receiving device.

[0049] (Fourth Embodiment) As shown in Figure 11, the sensor unit 10C of this embodiment includes a support portion 16A, a rod 20A, a pivot portion 22, a sensor module 12, a second spring 38, and a first spring 32, which are related to another configuration example. In the sensor unit 10C, components similar to those described in detail above are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0050] In one example, the support portion 16A is formed, for example, in the shape of a plate. A rod insertion hole 44 is formed in the center of the support portion 16A, penetrating in the direction of the first axis. The rod insertion hole 44 extends along the first axis L1. The rod insertion hole 44 is formed in a non-circular shape when viewed from the direction of the first axis.

[0051] The rod 20A is inserted into the rod insertion hole 44 and is supported by the support portion 16A so as to be displaced along the rod insertion hole 44 in the first axial direction. The rod 20A comprises a rod body portion 46 extending in the first axial direction, a retaining member 60A, and an enlarged diameter portion 50A. The rod body portion 46 is positioned in the rod insertion hole 44 of the support portion 16A and displaces the rod insertion hole 44 in the first axial direction. The rod body portion 46 is non-rotatable around the first axis L1 because its cross-sectional shape perpendicular to the first axial direction is formed in the same non-circular shape as the cross-sectional shape of the rod insertion hole 44. The retaining member 60A is located at the base end of the rod 20A. The retaining member 60A has an outer diameter larger than the rod insertion hole 44 and prevents the rod 20A from being pulled out toward the tip by catching on the support portion 16A.

[0052] The enlarged diameter portion 50A is located at the tip of the rod 20A. The enlarged diameter portion 50A bulges radially outward from the rod body portion 46. A first contact surface 62 that contacts the second spring 38 is formed on the tip side of the enlarged diameter portion 50A. A base end surface that contacts the first spring 32 is formed on the base end side of the enlarged diameter portion 50A.

[0053] A first through-hole 54 is formed in the center of the rod 20A, passing through the enlarged diameter portion 50A, the rod body portion 46, and the retaining member 60A in the first axial direction. The first through-hole 54 accommodates the connection wiring of the sensor module 12.

[0054] The first spring 32 is a coil spring and is positioned on the outer circumference of the rod 20A. The base end of the first spring 32 abuts against the tip of the support portion 16A. The tip of the first spring 32 also abuts against the base end surface of the enlarged diameter portion 50A. The first spring 32 biases the enlarged diameter portion 50A toward the tip, thereby returning the rod 20A to its initial position in the first axial direction. In the initial state, the rod 20A is biased toward the tip by the first spring 32, and the retaining member 60A abuts against the base end of the support portion 16A.

[0055] The pivot portion 22 extends from the rod 20A toward the tip. The pivot portion 22 is integrally formed with the rod body portion 46 and is arranged coaxially with the rod body portion 46. A spherical portion 72, whose outer surface is formed by a sphere, is formed at the tip of the pivot portion 22. A second through hole 74 extends in the first axial direction from the center of the pivot portion 22. The second through hole 74 opens at the tip of the pivot portion 22. The base end of the second through hole 74 communicates with the first through hole 54. The pivot portion 22 may also be formed as a separate part from the rod 20A and joined to the rod 20A.

[0056] The sensor module 12 is formed in a plate shape, in one example which is not particularly limited. The sensor module 12 may be, for example, an inspection prober with a plurality of probes provided on its tip side. The sensor module 12 may include a light transmitting / receiving element, an electromagnetic coil, or a temperature sensor, etc. A second contact surface 90 is formed on the base end side of the sensor module 12, which contacts the tip of the second spring 38.

[0057] A ball-receiving portion 34 is formed at the center of the base end of the sensor module 12, which fits into the spherical portion 72 of the pivot portion 22. The ball-receiving portion 34 has a curved surface that is slidable on the spherical surface of the spherical portion 72, and by sliding with the spherical portion 72, it pivotably connects the sensor module 12 to the rod 20A. The sensor module 12 has a second axis L2. In the initial position when the sensor module 12 is not in contact with the workpiece W, the second axis L2 is coaxial with the first axis L1.

[0058] A second spring 38 is positioned between the sensor module 12 and the rod 20A. The second spring 38 is a coiled compression spring and is positioned to surround the pivot portion 22. The second spring 38 is positioned between the enlarged diameter portion 50A and the sensor module 12.

[0059] The base end of the second spring 38 abuts against the first contact surface 62 of the enlarged diameter portion 50A and is supported from the inside by the first cylindrical portion 64 protruding from the enlarged diameter portion 50A. The first cylindrical portion 64 supports the second spring 38 from the inside, keeping the area near the base end of the second spring 38 parallel to the first axial direction. A first notch 66 is formed in a part of the circumferential direction of the first cylindrical portion 64, which fits with the first bent portion 38b of the second spring 38. The first notch 66 connects the second spring 38 to the rod 20A in a way that prevents rotation.

[0060] The tip of the second spring 38 abuts against the second contact surface 90 of the sensor module 12 and is supported from the inside by a second cylindrical portion 92 that protrudes from the sensor module 12 toward the base end. The second cylindrical portion 92 supports the second spring 38 from the inside, keeping the area near the tip of the second spring 38 parallel to the second axis L2. A second notch 92b is formed in a part of the circumferential direction of the second cylindrical portion 92, which fits with the second bent portion 38d of the second spring 38. The second notch 92b fits with the second bent portion 38d, thereby supporting the second end portion 38c of the second spring 38 so that it cannot rotate relative to the sensor module 12.

[0061] In the sensor unit 10C of this embodiment, in the initial position when the sensor module 12 is not in contact with the workpiece W, the elastic force of the second spring 38 causes the first axis L1 of the rod 20A and the second axis L2 of the sensor module 12 to align coaxially. Furthermore, the circumferential position of the sensor module 12 aligns with the circumferential position of the rod 20A at a predetermined initial angle.

[0062] When the sensor module 12 contacts the workpiece W, the rod 20A is displaced in the first axial direction according to the position and inclination of the surface 120a of the workpiece W, causing the sensor module 12 to oscillate. This allows the contact surface 78 of the sensor module 12 to be suitably brought into close contact with the surface 120a of the workpiece W. When the sensor module 12 is separated from the workpiece W, the rod 20A returns to its initial position due to the elastic force of the second spring 38 and the first spring 32, and the sensor module 12 returns to its initial position. In addition, the rotational displacement of the sensor module 12 is returned to its initial angle. As a result, the second spring 38 can prevent the wiring from breaking due to the accumulation of rotational displacement of the sensor module 12.

[0063] (Fifth Embodiment) As shown in Figure 12, the sensor unit 10D of this embodiment includes a support portion 16D, a rod 20D, a pivot portion 22, a sensor module 12, a first spring 32, and a second spring 38, which are related to another configuration example. In the sensor unit 10D, components similar to those described in detail above are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0064] The support portion 16D is formed in the shape of a rod extending in the first axial direction. A third through hole 122 is formed in the center of the support portion 16D, penetrating in the first axial direction. The base end of the support portion 16D is fixed to a robot arm 116 or the like.

[0065] The support portion 16D is housed in the cylinder chamber 124 of the rod 20D. The support portion 16D has a first projection 126 and a second projection 128 that are slidable against the inner wall of the cylinder chamber 124. The first projection 126 is located near the base end of the support portion 16D. In the initial position, the first projection 126 abuts against the base end wall 130 of the rod 20D, preventing the rod 20D from being pulled out towards the tip. The second projection 128, together with the first projection 126, abuts against the inner wall of the cylinder chamber 124, guiding the orientation and displacement direction of the rod 20D in the first axial direction.

[0066] The rod 20D has a larger outer diameter than the support portion 16D. The rod 20D has a cylinder chamber 124 in its center that houses the support portion 16D. A base end wall 130 is formed on the base end side of the cylinder chamber 124, and a tip wall 132 is formed on the tip side of the cylinder chamber 124. The base end wall 130 has a support portion insertion hole 134 through which the support portion 16D is inserted. The cylinder chamber 124 extends in a first axial direction, and its inner circumferential surface slides relative to the support portion 16D in the first axial direction. A first spring 32 is housed at the tip of the cylinder chamber 124.

[0067] The first spring 32 can be made of, for example, a compression coil spring. The tip of the first spring 32 abuts against the tip wall 132, and the base end of the first spring 32 abuts against the tip of the support portion 16D. The first spring 32 biases the rod 20D toward the tip.

[0068] The tip wall 132 of the rod 20D has a first through-hole 54 that penetrates the tip wall 132 in the first axial direction. The first through-hole 54 communicates with a third through-hole 122 of the support portion 16D via a cylinder chamber 124. Connection wiring for the sensor module 12 is arranged in the first through-hole 54, the cylinder chamber 124, and the third through-hole 122. The connection wiring passes inside the first spring 32 and extends out to the upper end of the sensor unit 10D through the third through-hole 122.

[0069] A first contact surface 62 perpendicular to the first axial direction is formed at the tip of the rod 20D. A short cylindrical first tube portion 64 protrudes from the first contact surface 62 toward the tip. The first tube portion 64 supports the second spring 38 from the inside, thereby maintaining the centerline of the second spring 38 near its first end 38a in the first axial direction. In addition, a first notch 66 is formed in a part of the circumferential direction of the first tube portion 64, which fits with the first bent portion 38b of the second spring 38. The first notch 66, by fitting with the first bent portion 38b, supports the first end 38a of the second spring 38 so that it cannot rotate relative to the rod 20D.

[0070] The pivot portion 22 protrudes from the tip of the rod 20D toward the tip. The pivot portion 22 has a spherical portion 72 at the tip of the rod-shaped portion 70. The spherical portion 72 is formed in a spherical shape. A second through hole 74 is formed in the center of the pivot portion 22, penetrating in the first axial direction. The second through hole 74 communicates with the first through hole 54.

[0071] The sensor module 12 is not particularly limited, but for example, it is formed in a cylindrical shape centered on the second axis L2. A second contact surface 90 that contacts the second spring 38 is formed on the base end side of the sensor module 12.

[0072] A ball-receiving portion 34 is formed at the base end of the sensor module 12, which fits into the spherical portion 72 of the pivot portion 22. The ball-receiving portion 34 has a curved surface that slides against the spherical portion 72. By sliding against the spherical portion 72, the ball-receiving portion 34 allows the sensor module 12 to swing relative to the rod 20D. In the initial position when the sensor module 12 is not in contact with the workpiece W or the like, the second axis L2 is aligned coaxially with the first axis L1.

[0073] A second cylindrical portion 92 extends a short distance from the second contact surface 90 of the sensor module 12 toward the base end. The second cylindrical portion 92 supports the second spring 38 from the inside, thereby maintaining the centerline of the second spring 38 near its second end 38c in the direction of the second axis. In addition, a second notch 92b is formed in a part of the circumferential direction of the second cylindrical portion 92, which fits with the second bent portion 38d of the second spring 38. The second notch 92b, by fitting with the second bent portion 38d, supports the second spring 38 so that it cannot rotate relative to the sensor module 12.

[0074] The second spring 38 is positioned between the sensor module 12 and the rod 20D. The second spring 38 is a coiled compression spring and is positioned to surround the pivot portion 22. The shape of the second spring 38 is as described with reference to Figure 4A.

[0075] In the sensor unit 10D of this embodiment, in the initial position when the sensor module 12 is not in contact with the workpiece W, the elastic force of the second spring 38 causes the first axis L1 of the rod 20D and the second axis L2 of the sensor module 12 to align coaxially. In addition, the circumferential position of the sensor module 12 aligns with the circumferential position of the rod 20D at a predetermined initial angle.

[0076] When the sensor module 12 contacts the workpiece W, the rod 20D is displaced in the first axial direction in accordance with the inclination of the surface 120a of the workpiece W and the deformation of the workpiece W in the first axial direction, causing the sensor module 12 to swing and the second axis L2 to tilt with respect to the first axis L1. This allows the contact surface 78 of the sensor module 12 to be suitably in close contact with the surface 120a of the workpiece W. When the sensor module 12 is separated from the workpiece W, the rod 20D returns to its initial position due to the elastic force of the second spring 38 and the first spring 32, and the sensor module 12 returns to its initial position. In addition, the rotational displacement of the sensor module 12 is returned to its initial angle. This prevents the wiring from breaking due to the accumulation of rotational displacement of the sensor module 12.

[0077] (Sixth Embodiment) As shown in Figure 13, the sensor unit 10E of this embodiment comprises a support portion 16E, a rod 20E, a pivot portion 22, a sensor module 12, a second spring 38, and a fluid pressure cylinder 136 (first return mechanism 24) according to another configuration example. In the sensor unit 10E, components similar to those described in detail above are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0078] The support portion 16E is formed in a plate shape. A third through-hole 122E is formed in the center of the support portion 16E, penetrating in the first axial direction. Multiple fluid pressure cylinders 136 are attached to the tip of the support portion 16E.

[0079] The fluid pressure cylinder 136 includes a cylinder chamber 138, a piston 140, and a piston rod 142. The cylinder chamber 138 extends in the direction of a first axis. The cylinder chamber 138 is filled with a compressible fluid such as air. The piston 140 is displaced in the direction of the first axis within the cylinder chamber 138. The piston rod 142 protrudes from the piston 140 toward its tip. A rod 20E is connected to the tip of the piston rod 142. Multiple fluid pressure cylinders 136 are provided between the support portion 16E and the rod 20E. The rod 20E is supported by the support portion 16E via the fluid pressure cylinder 136. The rod 20E is displaceable along the first axis L1 by the fluid pressure cylinder 136. When the sensor module 12 is not in contact with the workpiece W, the fluid pressure cylinder 136 constitutes a first return mechanism 24 that returns the rod 20E to its initial position in the direction of the first axis. The fluid pressure cylinder 136 may be replaced with an elastic material such as rubber or a spring.

[0080] The rod 20E may be formed in a plate shape, as is not a particularly limited example. Alternatively, the rod 20E may be a rod-shaped object extending long in the first axial direction. The rod 20E has a first through-hole 54 extending along its first axis L1. The first through-hole 54 penetrates the rod 20E in the first axial direction and communicates with a second through-hole 74. Connection wiring for the sensor module 12 is routed through the first through-hole 54.

[0081] A first contact surface 62 is formed at the tip of the rod 20E, which contacts the second spring 38. The first contact surface 62 is formed by a plane perpendicular to the first axis L1. A short first cylindrical portion 64 extends from the first contact surface 62 toward the tip in the first axial direction. The first cylindrical portion 64 supports the second spring 38 from the inside, thereby keeping the base end (first end 38a) of the second spring 38 in the first axial direction. In addition, a first notch 66 is formed in a part of the circumferential direction of the first cylindrical portion 64, which fits with the first bent portion 38b of the second spring 38. The first notch 66, by fitting with the first bent portion 38b, holds the second spring 38 in a non-rotatable position relative to the rod 20E.

[0082] The pivot portion 22 protrudes from the tip of the rod 20E toward the tip. The pivot portion 22 comprises a rod-shaped portion 70 extending in a rod shape along the first axis L1, and a spherical portion 72 formed at the tip of the rod-shaped portion 70. The spherical portion 72 is formed in a spherical shape. A second through-hole 74 is formed in the center of the pivot portion 22, penetrating in the direction of the first axis. The second through-hole 74 communicates with the first through-hole 54.

[0083] The sensor module 12 is formed in a disc shape centered on the second axis L2. The sensor module 12 may also be cylindrical. The sensor module 12 may be, for example, an inspection prober with multiple probes provided at its tip. The sensor module 12 may include sensors such as a light transmitting / receiving element, a coil 12b, or a temperature sensor. The sensor module 12 has a second contact surface 90 at its base end that contacts the tip of the second spring 38. The second contact surface 90 is formed by a plane perpendicular to the second axis L2.

[0084] A ball-receiving portion 34 is formed at the base end of the sensor module 12, which fits into the spherical portion 72 of the pivot portion 22. The ball-receiving portion 34 has a curved surface on which the spherical portion 72 can slide. By sliding with the spherical portion 72, the ball-receiving portion 34 enables the second axis L2 of the sensor module 12 to swing inclined with respect to the first axis L1. In the initial position when the sensor module 12 is not in contact with the workpiece W or the like, the second axis L2 is aligned coaxially with the first axis L1.

[0085] A second spring 38 is positioned between the sensor module 12 and the rod 20E. The second spring 38 is a coiled compression spring and is positioned to surround the pivot portion 22. The shape of the second spring 38 is as described with reference to Figure 4A.

[0086] A second cylindrical portion 92 extends a short distance from the second contact surface 90 of the sensor module 12 toward its base end in the first axial direction. The second cylindrical portion 92 is in contact with the second spring 38 and supports the second spring 38 from the inside. The second cylindrical portion 92 aligns the tip (second end portion 38c) of the second spring 38 with the second axial direction. In addition, a second notch 92b is formed in a part of the circumferential direction of the second cylindrical portion 92, which fits with the second bent portion 38d of the second spring 38. By fitting with the second bent portion 38d, the second notch 92b supports the second spring 38 so that it cannot rotate relative to the sensor module 12.

[0087] In the sensor unit 10E of this embodiment, in the initial position when the sensor module 12 is not in contact with the workpiece W, the elastic force of the second spring 38 causes the first axis L1 of the rod 20E and the second axis L2 of the sensor module 12 to align coaxially. Furthermore, the circumferential position of the sensor module 12 aligns with the circumferential position of the rod 20E at a predetermined initial angle.

[0088] When the sensor module 12 contacts the workpiece W, the rod 20E is displaced in the first axial direction in accordance with the inclination of the surface 120a of the workpiece W and the deformation of the workpiece W in the first axial direction. In addition, the sensor module 12 swings in accordance with the inclination of the surface 120a of the workpiece W, and the second axis L2 is inclined with respect to the first axis L1. This allows the contact surface 78 of the sensor module 12 to be suitably in close contact with the surface 120a of the workpiece W. When the sensor module 12 is separated from the workpiece W, the rod 20E returns to its initial position due to the elastic force of the second spring 38 and the first spring 32, and the sensor module 12 returns to its initial position. In addition, the rotational displacement of the sensor module 12 is returned to its initial angle. This prevents disconnection of the connecting wiring due to the accumulation of rotational displacement of the sensor module 12.

[0089] (Seventh Embodiment) The sensor unit 10F of this embodiment shown in Figure 14 comprises a support portion 16, a rod 20, a pivot portion 22, a sensor module 12, an elastic member 144 (second return mechanism 26), and a first spring 32, which are related to another configuration example. In the sensor unit 10F, components similar to those described in detail above are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0090] As described with reference to Figures 2 and 3, the support portion 16 is formed in a cylindrical shape. Inside the support portion 16, a cylinder chamber 40 is formed to house the rod 20 so that it can be displaced in the first axial direction. A base end wall 42 is formed at the base end of the cylinder chamber 40. A rod insertion hole 44 is formed in the base end wall 42 through which the rod 20 is inserted. The rod insertion hole 44 is formed in a non-circular shape to prevent the rod 20 from rotating around the first axis L1.

[0091] The rod 20 comprises a rod body portion 46 and an enlarged diameter portion 50. The rod body portion 46 has an outer diameter smaller than the inner diameter of the cylinder chamber 40. Therefore, a cylindrical gap capable of accommodating the first spring 32 is formed between the rod body portion 46 and the inner circumferential surface of the cylinder chamber 40 inside the cylinder chamber 40. The base end of the rod body portion 46 penetrates the base end wall 42 and protrudes towards the base end side of the support portion 16. The rod body portion 46 slides with the rod insertion hole 44 and is displaced in the first axial direction.

[0092] The enlarged diameter portion 50 is located at the tip of the rod body portion 46. The enlarged diameter portion 50 has a larger outer diameter than the rod body portion 46 and slides in contact with the inner circumferential surface of the cylinder chamber 40. The enlarged diameter portion 50 and the rod insertion hole 44 guide the displacement direction of the rod 20 in the direction of the first axis. The rod body portion 46 or the enlarged diameter portion 50 is supported by the support portion 16 in a state in which rotation around the first axis L1 is restricted relative to the support portion 16.

[0093] The first spring 32 is a coil spring and is positioned in the gap between the rod 20 and the support portion 16 formed in the cylinder chamber 40. The first spring 32 constitutes a first return mechanism 24 that returns the rod 20 to its initial position in the first axial direction.

[0094] The rod 20 has a first through-hole 54 that penetrates its center in the direction of the first axis. Wiring connected to the sensor module 12 is placed in the first through-hole 54. The wiring extends through the first through-hole 54 to the upper end of the sensor unit 10F.

[0095] The pivot portion 22 protrudes from the tip of the rod 20 toward the tip. The pivot portion 22 comprises a rod-shaped portion 70 extending in a rod shape along the first axis L1, and a spherical portion 72 formed at the tip of the rod-shaped portion 70. The spherical portion 72 is formed in a spherical shape. A second through hole 74 is formed in the center of the pivot portion 22, penetrating in the direction of the first axis. The second through hole 74 communicates with the first through hole 54.

[0096] The sensor module 12 is not particularly limited, but for example, it is formed in a cylindrical shape. The sensor module 12 includes, for example, a coil 12b (electromagnetic coil). The sensor module 12 may also include, instead of the coil 12b, a light transmitting / receiving element, a plurality of electrode pads, or a temperature sensor. A second contact surface 90 is formed on the base end side of the sensor module 12, which contacts the tip of the elastic member 144.

[0097] A ball-receiving portion 34 is formed at the center of the base end of the sensor module 12, which fits into the spherical portion 72 of the pivot portion 22. The ball-receiving portion 34 is formed of a spherical surface and slides with the spherical portion 72, allowing the sensor module 12 to swing relative to the rod 20. The sensor module 12 has a second axis L2 along its centerline.

[0098] A second return mechanism 26 is positioned between the sensor module 12 and the rod 20. The second return mechanism 26 in this embodiment comprises a plurality of elastic members 144. Each elastic member 144 is composed of a coil spring, a columnar elastomer, or a leaf spring, etc. The plurality of elastic members 144 are arranged to surround the pivot portion 22. The base end of each elastic member 144 is joined to the first contact surface 62 of the enlarged diameter portion 50 of the rod 20. The tip of each elastic member 144 is joined to the second contact surface 90 of the sensor module 12. The plurality of elastic members 144 are elastically deformable in the compression and tension directions. The lengths of each of the plurality of elastic members 144 in the first axial direction are equal. In the initial state when the sensor module 12 is not in contact with the workpiece W, the plurality of elastic members 144 maintain the orientation of the sensor module 12 in an initial position in which its second axis L2 is coaxial with the first axis L1. Furthermore, the circumferential position of the sensor module 12 is maintained at a predetermined initial angle with respect to the circumferential position of the rod 20.

[0099] When the sensor module 12 contacts the workpiece W, the multiple elastic members 144 elastically deform in accordance with the inclination of the surface 120a of the workpiece W and the deformation of the workpiece W in the first axial direction. The sensor module 12 also swings around the spherical portion 72 of the pivot portion 22, causing the second axis L2 to tilt with respect to the first axis L1. Furthermore, as the first spring 32 contracts, the position of the sensor module 12 in the first axial direction changes together with the rod 20. As a result, the sensor module 12 is displaced to follow the surface 120a of the workpiece W, and the contact surface 78 of the sensor module 12 can be brought into good contact with the surface 120a of the workpiece W.

[0100] When the sensor module 12 is separated from the workpiece W, the multiple elastic members 144 return to their original position due to their elastic restoring force, and the sensor module 12 returns to its initial position. Also, the elastic force of the first spring 32 returns the rod 20 to its initial position in the first axial direction, and the sensor module 12 returns to its initial position. Furthermore, the elastic restoring force of the first spring 32 returns the position of the sensor module 12 in the first axial direction to its initial position. In addition, the rotational displacement of the sensor module 12 relative to the rod 20 is returned to its initial angle by the elastic restoring force of the multiple elastic members 144. In this way, the elastic members 144 prevent disconnection of the connecting wiring due to the accumulation of rotational displacement of the sensor module 12.

[0101] With regard to the above embodiments, the following additional information is disclosed.

[0102] (Note 1) The sensor units (10, 10A, 10B, 10C, 10D, 10E, 10F) of this disclosure include a rod (20, 20A, 20D, 20E) extending along a first axis (L1), a support portion (16, 16A, 16D, 16E) that supports the rod so as to be movable in the direction of the first axis, a first return mechanism (24) that returns the position of the rod in the direction of the first axis to its initial position, a ball joint (36) provided at the tip of the rod, and a component attached to the ball joint. The device comprises a sensor module (12) that can swing around the ball joint, and a second return mechanism (26) connected to the rod and the sensor module, which returns the orientation of the sensor module to its initial orientation. The second return mechanism has a first end (38a) connected to the rod so as not to shift its circumferential position relative to the first axis, and a second end (38c) connected to the sensor module so as not to shift its circumferential position relative to the first axis.

[0103] The above sensor unit improves the tracking ability of the sensor module to the object being measured while preventing disconnection of the connection wiring of the sensor module.

[0104] (Note 2) The sensor unit described in Note 1, wherein the sensor module has a second axis (L2), and the initial position is such that the first axis and the second axis are coaxially aligned, and the circumferential rotation angle of the sensor module with respect to the first axis relative to the rod is the initial angle. The sensor unit with this configuration can suitably bring the sensor module into contact with a workpiece having an inclined surface.

[0105] (Note 3) In the sensor unit described in Note 1, the second return mechanism may be a coil-shaped second spring (38) that surrounds the ball joint and extends in the direction of the first axis. This configuration simplifies the device configuration of the sensor unit.

[0106] (Note 4) The sensor unit described in Note 3 may have the following configuration: the rod has a first contact surface (62) at its tip that is a plane perpendicular to the first axis; the sensor module has a second axis located at the center and a second contact surface (90) formed at its base that is a plane perpendicular to the second axis; and the second spring has a first end surface (38e) formed at the first end that is a plane perpendicular to the center line of the second spring in its initial shape and makes surface contact with the first contact surface; and a second end surface (38f) formed at the second end that is a plane parallel to the first end surface in the initial shape of the second spring and makes surface contact with the second contact surface. With this configuration, the misalignment between the first axis and the second axis in the initial position is suppressed.

[0107] (Note 5) The sensor unit described in Note 1, wherein the support portion has a cylinder (30) that supports the rod and is displaceable in the direction of the first axis, and the first return mechanism has a first spring (32) housed in the cylinder. With this configuration, the first return mechanism is simplified.

[0108] (Note 6) The sensor unit described in Note 1 may have a plurality of elastic members (144) arranged to surround the ball joint and having equal lengths in the direction of the first axis. This configuration of the sensor unit can improve the tracking ability of the sensor module to the object being measured while preventing disconnection of the connection wiring of the sensor module.

[0109] (Note 7) The sensor unit described in Note 1 may have a support portion which supports the rod and has a fluid pressure cylinder (136) that is displaceable in the direction of the first axis. This configuration of the sensor unit facilitates adjustment of the response characteristics of the sensor module to axial displacement.

[0110] (Note 8) The sensor unit described in Note 1 comprises a first through-hole (54) through which the rod passes in the direction of the first axis, a second through-hole (74) through which the ball joint passes in the direction of the first axis and communicates with the first through-hole, and a third through-hole (60a, 122) through which the support portion passes in the direction of the first axis and communicates with the first through-hole, wherein the connection wiring of the sensor module may be arranged in the first through-hole, the second through-hole and the third through-hole. With this configuration, the connection wiring is protected by housing it inside the sensor unit, and disconnection of the connection wiring is suppressed.

[0111] (Note 9) The sensor unit described in any one of Notes 1 to 8 may include a housing (96) connected to the base end of the support portion, a circuit board housed inside the housing for processing the detection signal of the sensor module, and a display unit (110) provided in the housing for displaying the detection value of the sensor module. This configuration allows for miniaturization of the sensor unit and the display device.

[0112] (Note 10) The sensor unit described in Note 9 may include a bellows (18) whose base end is joined to the housing and whose tip end is joined to the sensor module. This configuration prevents dust from entering the pivot portion.

[0113] (Note 11) A sensor unit according to any one of Notes 1 to 8, wherein the sensor module comprises a cylindrical outer core (12d), a rod-shaped inner core (12c) extending cylindrically along the center of the outer core, and a coil (12b) wound between the outer core and the inner core. A sensor unit with this configuration can suitably detect the thickness of a magnetic workpiece, etc.

[0114] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0115] 10, 10A, 10B, 10C, 10D, 10E, 10F... Sensor unit 12b... Coil 12d... Outer core 16, 16A, 16D, 16E... Support part 18... Bellows 20, 20A, 20D, 20E... Rod 24... First return mechanism 26... Second return mechanism 30... Cylinder 32... First spring 36... Ball joint 38... Second spring 96... Housing 110... Display unit 136... Fluid pressure cylinder 144... Elastic member L1... First axis L2... Second axis

Claims

1. A sensor unit (10, 10A to 10F) comprising: a rod (20, 20A, 20D, 20E) extending along a first axis (L1); a support portion (16, 16A, 16D, 16E) that supports the rod so as to be movable in the direction of the first axis; a first return mechanism (24) that returns the position of the rod in the direction of the first axis to its initial position; a ball joint (36) provided at the tip of the rod; a sensor module (12) attached to the ball joint and pivotable about the ball joint; and a second return mechanism (26) connected to the rod and the sensor module and that returns the orientation of the sensor module to its initial orientation, wherein the second return mechanism has a first end portion (38a) connected to the rod so as not to shift its circumferential position relative to the first axis; and a second end portion (38c) connected to the sensor module so as not to shift its circumferential position relative to the first axis.

2. A sensor unit according to claim 1, wherein the sensor module has a second axis (L2), and the initial position is such that the first axis and the second axis are coaxially aligned, and the circumferential rotation angle of the sensor module with respect to the first axis relative to the rod is the initial angle.

3. A sensor unit according to claim 1, wherein the second return mechanism is a coil-shaped second spring (38) that surrounds the ball joint and extends in the direction of the first axis.

4. A sensor unit according to claim 3, wherein the rod has a first contact surface (62) at its tip that is a plane perpendicular to the first axis, the sensor module has a second axis located at the center, and a second contact surface (90) formed at the base end that is a plane perpendicular to the second axis, and the second spring has a first end surface (38e) formed at the first end that is a plane perpendicular to the center line of the second spring in the initial shape of the second spring and makes surface contact with the first contact surface, and a second end surface (38f) formed at the second end that is a plane parallel to the first end surface in the initial shape of the second spring and makes surface contact with the second contact surface.

5. A sensor unit according to claim 1, wherein the support portion has a cylinder (30) that supports the rod and is displaceable in the direction of the first axis, and the first return mechanism has a first spring (32) housed in the cylinder.

6. A sensor unit according to claim 1, wherein the second return mechanism has a plurality of elastic members (144) arranged to surround the ball joint and having equal lengths in the direction of the first axis.

7. A sensor unit according to claim 1, wherein the support portion has a fluid pressure cylinder (136) that supports the rod and is displaceable in the direction of the first axis.

8. A sensor unit according to claim 1, comprising: a first through hole (54) through the rod in the direction of the first axis; a second through hole (74) through the ball joint in the direction of the first axis and communicating with the first through hole; and a third through hole (60a, 122) through the support portion in the direction of the first axis and communicating with the first through hole, wherein connection wiring for the sensor module is arranged in the first through hole, the second through hole and the third through hole.

9. A sensor unit according to any one of claims 1 to 8, comprising: a housing (96) connected to the base end of the support portion; a circuit board housed inside the housing and processing the detection signal of the sensor module; and a display unit (110) provided in the housing and displaying the detection value of the sensor module.

10. A sensor unit according to claim 9, comprising a bellows (18) whose base end is joined to the housing and whose tip end is joined to the sensor module.

11. A sensor unit according to any one of claims 1 to 8, wherein the sensor module comprises: a cylindrical outer core (12d); a rod-shaped inner core (12c) extending cylindrically along the center of the outer core; and a coil (12b) wound between the outer core and the inner core.

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