JP4485870B2 - Ultrasonic probe - Google Patents

Description

  The present invention relates to an ultrasonic probe, and more particularly to a technique for protecting a position detector.

  A mechanical scanning type ultrasonic probe (probe) includes an ultrasonic transducer and a mechanism for mechanically scanning the ultrasonic transducer. Here, the ultrasonic transducer is, for example, a single transducer or a 1D array transducer. In the former case, a two-dimensional scanning surface is formed by mechanical scanning of a single transducer, and in the latter case, a three-dimensional echo data capturing area (three-dimensional space) is formed by mechanical scanning of a 1D array transducer. .

  In the above-described ultrasonic probe, generally, a medium chamber filled with an acoustic propagation medium is provided in the probe case in order to ensure acoustic propagation regardless of the motion of the ultrasonic transducer. That is, the ultrasonic transducer is mechanically scanned in the medium chamber. Although a drive motor, a gear mechanism, and the like can be provided outside the medium chamber, it is also conceivable that the drive motor, the gear mechanism, and the like are accommodated in the medium chamber from the viewpoint of maintaining airtightness of the medium chamber. Japanese Patent Application Laid-Open Publication No. 2004-228561 discloses a mechanical scanning ultrasonic probe, in which a medium chamber that accommodates an acoustic medium and a space that accommodates a gear mechanism are separated by a partition film. Patent Document 1 also discloses an angle detector. Patent Document 2 discloses a position input device as a mouse. Ring-shaped dust removal means is provided around the exposed portion of the sphere. Although details of the dust removal means are not described in detail in this document, the dust removal means contacts the surface of the sphere and removes the dust attached to the surface.

Japanese Patent Laid-Open No. 3-184532 Japanese Patent Laid-Open No. 7-13692

  A sensor is provided in the ultrasonic probe to detect the movement position of the ultrasonic transducer. As such a sensor, an optical rotary encoder or the like is known. On the other hand, it is conceivable to use a magnetic sensor or the like in order to further improve the position detection resolution. When a gear mechanism is accommodated in the medium chamber, wear powder (metal powder) may be generated or may be slightly generated with the operation of the gear mechanism. Further, there is a possibility that foreign matters such as burrs and dust generated during the molding are present in the medium. If such foreign matter enters between the magnetic surface (detected surface) of the magnetic drum and the sensor surface (detected surface) of the magnetic sensor, it may damage the detection surface of the magnetic sensor or reduce its detection accuracy. Is assumed. In addition, when a foreign substance is floating or moving in the medium chamber, the optical detection by the optical sensor may be adversely affected, and other problems may be caused. In particular, the above problem becomes prominent because wear powder is easily attracted by the magnetic force of the magnetic drum.

  It is an object of the present invention to prevent the position detector from being deteriorated or the detection accuracy from being lowered even if a foreign substance is floating in the medium in the ultrasonic probe.

  It is an object of the present invention to maintain and improve operation reliability or detection accuracy of a position detector.

(1) The present invention provides a case having a medium chamber filled with an acoustic medium, an ultrasonic transducer that moves in the medium chamber, and a movement position of the ultrasonic transducer that is provided in the medium chamber. A position detector, wherein the position detector has a detected member that moves together with the ultrasonic transducer, and a detection surface that is close to and faces the detected surface of the detected member. And a sensor for detecting relative movement, and an entry restricting means for preventing entry of a foreign substance into a gap between the detection surface and the detection surface is provided.

  According to the above configuration, the entry restricting means restricts the entry of foreign matter into the gap (detection space) between the detection surface and the detection surface. The foreign material is, for example, metallic wear powder generated by the gear mechanism, but other floating bodies can be prevented from entering as well. Therefore, it is possible to prevent problems such as foreign matter entering the gap and clogging or damaging the detection surface. In particular, when the position detector is constituted by a magnetic drum and a magnetic sensor, wear powder is easily attracted to the magnetic drum, but foreign matter can be prevented from entering the gap by the above-described entry restricting means.

  Desirably, the said approach control means has the member which is provided in the foreign material approach side in the said clearance gap, and the said foreign material collides. Desirably, the detected member reciprocates with the reciprocating motion of the ultrasonic transducer, and the entry restricting means is provided on both sides of the clearance in the reciprocating direction, and a pair of members that the foreign matter collides with are provided. Have. If the detected member moves only in one direction, it is only necessary to provide an entry restriction means on one side of the gap (foreign material entry side), but if the detected member reciprocates, entry restriction is provided on both sides of the gap. It is desirable to provide means. Furthermore, both openings in a direction perpendicular to the direction of motion of the detected surface in the gap may be left open or concealed.

  Preferably, the entry restricting means includes a roller member provided close to or in contact with the detected surface. Preferably, the roller member is driven to rotate when the detected member contacts the detected surface. Preferably, the roller member has a rotating shaft and a cylindrical elastic body that rotates around the rotating shaft. Preferably, a gap exists between the outer diameter of the rotating shaft and the inner diameter of the cylindrical elastic body, and the cylindrical elastic body is displaced in one direction while being supported by the rotating shaft. The surface of the cylindrical elastic body comes into contact with the detected surface when the surface of the cylindrical elastic body is detached from the detection surface and the cylindrical elastic body is displaced to the other side while being supported by the rotating shaft. To do.

  According to the said structure, the approach of a foreign material can be controlled using a roller member. If the roller member is rotatable or is attached with a degree of freedom, it is advantageous because even if it is in contact with the surface to be detected, a load is not applied to the member to be detected more than necessary. In addition, it can also arrange | position so that a roller surface may always contact a to-be-detected surface, and a roller surface can always be arrange | positioned at a very small distance from the to-be-detected surface. In consideration of the size of the foreign matter and the load caused by the frictional resistance of the roller surface, it is desirable to adopt the optimum configuration for the situation.

  Preferably, the member to be detected is a member that rotates, and an outer peripheral surface thereof is the surface to be detected. Preferably, the member to be detected is a member that rotates, and the side surface thereof is the surface to be detected. That is, the entry restriction means can be provided at various positions depending on the detection method.

(2) The present invention provides a case having a medium chamber filled with an acoustic medium, an ultrasonic transducer that moves in the medium chamber, and a movement force that is provided in the medium chamber and that exerts a kinetic force on the ultrasonic transducer. A gear mechanism for transmitting, and a position detector that is provided in the medium chamber and detects a movement position of the ultrasonic transducer, and the position detector moves with the ultrasonic transducer; A gap between the sensor surface and the magnetic drum surface, the sensor surface having a sensor surface close to and opposed to the magnetic drum surface in the magnetic drum, and detecting a relative motion of the magnetic drum surface. An entry restricting means for preventing the entry of wear powder generated by the gear mechanism is provided.

  Desirably, the said entry control means is provided in the abrasion powder approach side in the said clearance gap, and has a member which contacts or adjoins to the said magnetic drum surface. As an approach control means, a brush member, a curtain-like member, etc. other than a rotatable roller member can be considered.

  In any case, it is desirable to provide a member that collides with a foreign object and restricts its entry on the foreign object entry side in the gap without applying an unnecessary load on the movement of the detected member. When the member to be detected moves at a high speed (especially when reciprocating at a high speed), it is particularly desirable to use a roller member that can stably exert a regulating action by such movement. It should be noted that the foreign substance regulating means used in combination with the position detector can be diverted to other than the ultrasonic probe.

  As described above, according to the present invention, it is possible to prevent the position detector from being deteriorated or the detection accuracy from being lowered even if a foreign object is floating in the ultrasonic probe. According to the present invention, it is possible to maintain and improve the operational reliability or detection accuracy of the position detector.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings.

  FIG. 1 shows a preferred embodiment of an ultrasonic probe according to the present invention, and FIG. 1 is a sectional view thereof.

  The ultrasonic probe shown in FIG. 1 is used in contact with the body surface of a living body, and transmits and receives ultrasonic waves. This ultrasonic probe is connected to an ultrasonic diagnostic apparatus (not shown). In the ultrasonic diagnostic apparatus, an ultrasonic image is formed based on a reception signal obtained by transmitting and receiving ultrasonic waves, and the ultrasonic image is displayed on the screen. The ultrasonic probe shown in FIG. 1 is a 3D probe that forms a three-dimensional echo data capturing space (3D space) by mechanically scanning an electronically scanned 1D array transducer. The specific configuration will be described below.

  The case of the ultrasonic probe includes an upper case member 10, a frame 12, and a lower case member 14. The upper case member 10 generally functions as a grip, and the lower case member 14 has a contact surface 14A that comes into contact with the surface of the living body. A medium chamber 16 is formed inside the case, and the medium chamber 16 is filled with an acoustic medium for ensuring acoustic propagation. The propagation medium is distilled water or oil. The medium chamber 16 is formed from the inside of the lower case member 14 to the inside of the upper case member 10, that is, the vibrator unit 17, the angle detector 24, the drive motor 30 and various gear mechanisms described below are the medium chamber 16. Is housed inside.

  A movable body 15 is provided inside the lower case member 14 so as to be capable of reciprocating in the paper surface penetrating direction in FIG. The movable body 15 includes a vibrator unit 17 and a mounting body 20. The transducer unit 17 has a ship-bottom shape, and its lower surface is a transmission / reception surface 17A through which ultrasonic waves pass. The wave transmitting / receiving surface 17 </ b> A is gently curved in an arc shape as shown in the drawing, and a plurality of vibration elements are arranged inside the vibrator unit 17 along the wave transmitting / receiving surface 17. The 1D array transducer is constituted by the plurality of vibration elements, and the ultrasonic beam formed thereby is electronically scanned in a fan shape by a so-called convex scanning method. Of course, the present invention is also applicable to other types of ultrasonic probes.

  The vibrator unit 17 and the attachment body 20 are fixedly connected, and the upper portion of the attachment body 20 is attached to the shaft 18. One end side of the shaft 18 is pivotally supported by the bearing member 21, and the other end side is pivotally supported by the first bearing portion 22 </ b> A of the bearing member 22. That is, the shaft 18 is provided so as to freely rotate, and the movable body 15 also rotates as the shaft 18 rotates. At the time of ultrasonic diagnosis, electronic scanning of the ultrasonic beam is repeatedly performed in the transducer unit 17, and accordingly, the transducer unit 17 swings (reciprocates) around the shaft 18. Thereby, a three-dimensional space is formed.

  The angle detector (position detector) 24 includes a magnetic sensor 26 fixedly disposed on the frame 12 and a magnetic drum 25 fixedly connected to the shaft 18. The magnetic drum 25 has a fan-shaped shape spreading upward, and its end surface (upper surface) is a magnetic drum surface (detected surface) 25A. On the magnetic drum surface 25A, magnetic poles are formed with a predetermined pattern. The magnetic sensor 26 has a sensor surface (detection surface) 26A, and the magnetic force generated from the magnetic pole formed on the magnetic drum surface 25A is sensed by the sensor surface 26A. The magnetic sensor 26 is composed of an MR element or the like, and the rotational position of the magnetic drum 25 is detected by the magnetic sensor 26. The magnetic drum surface 25A and the sensor surface 26A are placed in close proximity to each other, and the interval (the height of the detection space) is set as a minute interval of, for example, 0.5 mm or less in order to increase detection sensitivity. Is done. When foreign matter enters the gap, particularly when a metallic hard foreign matter such as wear powder enters, there is a problem that the sensor surface 26A is damaged or magnetic detection is adversely affected.

  Therefore, in the present embodiment, a foreign matter entry restriction mechanism 100 that prevents such a problem is provided. The foreign matter entry restricting mechanism 100 has a pair of roller members provided on both sides of the sensor surface 26A of the magnetic sensor 26 in the movement direction of the magnetic drum surface. The pair of roller members regulates and eliminates the entry of foreign matter into the gap when the magnetic drum 25 moves forward and backward. In addition, the rotating shaft of each roller member is hold | maintained by the 2nd bearing part 22B. The foreign matter entry restriction mechanism 100 will be described in detail later with reference to FIG.

  A drive motor 30 is provided in the upper case member 10. The motor shaft 32 of the drive motor 30 is connected to the planetary gear mechanism 34. The output side of the planetary gear mechanism 34 is connected to the output shaft 46, and a conversion gear mechanism 56 is provided on the lower end side of the output shaft 46. The conversion gear mechanism 56 includes a gear 58 fixedly arranged on the output shaft 46 side and a gear 60 fixedly arranged on the shaft 18, and the rotational movement of the output shaft 46 is caused by the meshing of these gears 58, 60. It is converted into a rotational movement of the shaft 18. The conversion gear mechanism 56 has a so-called bevel gear structure. The output shaft 46 is inserted through the frame 12 in the vertical direction, and a central portion thereof is rotatably held by the bearing mechanism 50. The bearing mechanism 50 includes a first bearing portion 52 and a second bearing portion 54 that are arranged side by side in the vertical direction. An acoustic medium also enters the bearing portions 52 and 54. That is, the opening type bearing mechanism 50 is employed. The same applies to the planetary gear mechanism 34 and the drive motor 30.

  The configuration of the planetary gear mechanism 34 will be described. As will be described later with reference to FIG. 2, the planetary gear mechanism 34 includes a gear portion 36 attached to the motor shaft 32, an external gear 40 fixedly installed inside the upper case member 10, and an inner side of the external gear 40. And a plurality of (four in the present embodiment) internal gears 38 that roll. Each internal gear 38 has an upper gear 39A and a lower gear 39B, and a cylindrical pin 42 is disposed as a shaft support member at the center portion thereof. In each internal gear 38, the upper gear 39A is arranged to mesh with both the gear portion 36 and the external gear 40, while the lower gear 39B is provided at the upper end of the external gear 40 and the output shaft 46. The gear portion is provided in mesh with the gear portion.

  Accordingly, when the motor shaft 32 is rotated, the rotational motion is transmitted as the rotational motion of the four internal gears 38, but the external gear 40 itself meshing with the internal gears 38 does not rotationally move. 38 itself rolls inside the external gear 40. Then, such rotational movement is transmitted to the gear portion of the output shaft 46 meshing with the lower gear 39B in each internal gear 38, and as a result, the output shaft 46 rotates. The rotational motion of the output shaft 46 is converted into the rotational motion of the shaft 18 by the conversion gear mechanism 56 described above. The drive motor 30 periodically rotates the motor shaft 32 in one direction and the other direction. As a result, the shaft 18 periodically rotates in one direction and the other direction. Will reciprocate in the direction of paper penetration.

  FIG. 2 conceptually shows the configuration of the planetary gear mechanism 34 described above. In FIG. 2, the movement of each gear when the motor shaft 32 is rotated in one direction is shown as an arrow. Of course, the motor shaft 32 rotates not only in one direction but also in the other direction.

  Four internal gears 38 are provided between the external gear 40 and the gear portion 36, and each internal gear 38 itself rotates inside the external gear 40 by the rotation of the gear portion 36, and simultaneously rolls. A space 45 is formed between the plurality of internal gears 38, and the acoustic medium flows in the vertical direction through the space 45. Incidentally, although a specific gear mechanism called the planetary gear mechanism 34 is used in this embodiment, another gear mechanism may be provided.

  FIG. 3 shows the foreign matter entry restriction mechanism 100 as an enlarged view. The magnetic drum 25 has a fan shape and reciprocates by the reciprocating rotation of the shaft 18 shown in FIG. The circumferential surface (outer peripheral surface) is a magnetic drum surface 25A as a detected surface. The sensor surface 26A as a detection surface in the magnetic sensor 26 is disposed close to the magnetic drum surface 25A, and the height of the gap is 0.5 mm or less as described above. The magnetic sensor 26 is held by a holder 27. In the direction of movement of the magnetic drum 25, a pair of roller members 101 are provided on the left and right ends of the holder 27 so as to close the left and right gap openings 130 </ b> A and 130 </ b> B in close proximity (that is, to close the foreign substance entrance). It has been. Each roller member 101 includes a rotation shaft 102 that is fixedly arranged and a cylindrical elastic body 104 that is rotatably supported by the rotation shaft 102. The cylindrical elastic body 104 has a width that is at least larger than the width of the magnetic drum surface 25A. There is a gap between the outer diameter of the rotating shaft 102 and the inner diameter of the cylindrical elastic body 104, that is, the cylindrical elastic body 104 can rotate with respect to the rotating shaft 102 under a low frictional resistance, and at the same time There is a certain degree of freedom of movement in the vertical and horizontal directions on the paper. Therefore, depending on the state of motion, the surface of the cylindrical elastic body 104 may be in contact with the magnetic drum surface 25A, or may be separated by a minute distance. The cylindrical elastic body is made of an elastic material such as silicone rubber.

  With the above configuration, when the magnetic drum 25 performs reciprocating rotational movement, a medium flow is generated thereby, and there is a possibility that foreign matter is drawn into the gap between the sensor surface 26A and the magnetic drum surface 25A. The collision with the roller member 101 is forcibly restricted, and foreign matter intrusion into the gap is effectively suppressed. Further, the medium flow is also changed by the roller member 101, and the flow into the gap is reduced. Even if metallic foreign matter (abrasion powder, burrs) adheres to the surface of the magnetic drum surface 25A due to the magnetic action, the roller member 101 comes into contact with the magnetic drum surface 25A and hits the foreign matter, or the distance between them is increased. When a very small foreign object hits the roller member 101, such a foreign object is removed. Therefore, foreign matter intrusion into the gap can be effectively suppressed, so that the operational reliability of the magnetic sensor 26 can be secured by protecting the sensor surface 26A.

  In the above configuration, it is desirable that the roller member 101 is in a positional relationship in which the roller member 101 is in contact with the magnetic drum surface 25A at all times or depending on the situation, but the same effect as described above can be obtained even if they do not necessarily contact. You may comprise so that the contact amount or height of the roller member 101 can be finely adjusted freely. You may make it further close the opening of the both sides in the direction orthogonal to the moving direction of the magnetic drum 25 in a clearance gap. Further, a protective coating may be applied to the magnetic drum surface 25A to protect the surface. Such processing can be performed on the sensor surface 26A as long as sufficient detection sensitivity is obtained.

  FIG. 4 shows another embodiment. In this embodiment, a circular slit plate 114 is fixed to a rotating shaft 112 connected to an object for position detection, and an optical sensor that irradiates a side surface (slit surface) of the slit plate 114 with a light beam. 118 is arranged. The sensor 118 is transmissive or reflective. A plurality of slits 116 are formed radially on the slit surface of the slit plate 114. The measurement light is transmitted through each slit 116 (no reflection occurs), and the rotation angle can be measured by measuring the presence of the slit 116. In this configuration, if a foreign object enters the gap between the sensor 118 and the slit surface, the above-mentioned problem occurs. Therefore, as shown in the figure, two roller members 120 and 122 are provided in the vicinity of the front and rear of the gap (that is, the foreign matter entrance on both sides when the slit plate 114 reciprocates). These roller members 120 and 122 also exhibit the same function as the roller member 101 described above. Also with such a configuration, the detector can be protected by restricting the entry of foreign matter, and the reliability of the operation can be improved.

  Instead of the roller member in each of the above embodiments, a spatula-like elastic blade, a brush, a curtain-like member, or the like may be provided as the entry restricting means. However, it is desirable to provide them so that foreign matters can be effectively removed without unnecessarily applying a motion load to the rotating member.

1 is a cross-sectional view of an ultrasonic probe according to the present invention. It is the schematic which shows the structure of a planetary gear. It is a figure explaining a foreign material approach control mechanism. It is a figure which shows the foreign material approach control mechanism which concerns on other embodiment.

Explanation of symbols

  10 upper case member, 12 frame, 14 lower case member, 15 movable body, 16 medium chamber, 17 transducer unit, 18 axis, 24 angle detector, 30 drive motor, 34 planetary gear mechanism, 50 bearing mechanism, 56 conversion gear Mechanism, 100 Foreign object entry restriction mechanism.

Claims (9)

A case having a medium chamber filled with an acoustic medium;
An ultrasonic transducer moving in the medium chamber;
A position detector provided in the medium chamber for detecting a movement position of the ultrasonic transducer;
Including
The position detector is
A member to be detected that moves with the ultrasonic transducer;
A sensor having a detection surface close to and opposite to the detection surface of the detection member, and detecting a relative movement of the detection member;
Have
An ultrasonic probe characterized in that an entry restricting means for preventing entry of a foreign substance into a gap between the detection surface and the detection surface is provided. The ultrasonic probe according to claim 1,
The ultrasonic probe according to claim 1, wherein the entry restricting means includes a roller member provided close to or in contact with the surface to be detected. The ultrasonic probe according to claim 2,
The ultrasonic probe according to claim 1, wherein the roller member is driven to rotate when the detection member contacts the detection surface. The ultrasonic probe according to claim 2,
The ultrasonic probe according to claim 1, wherein the roller member includes a rotation shaft and a cylindrical elastic body that rotates around the rotation axis. The ultrasonic probe according to claim 4,
There is a gap between the outer diameter of the rotating shaft and the inner diameter of the cylindrical elastic body,
When the cylindrical elastic body is displaced to one side while being supported by the rotating shaft, the surface of the cylindrical elastic body is detached from the detected surface,
When the cylindrical elastic body is displaced to the other while being supported by the rotating shaft, the surface of the cylindrical elastic body contacts the detected surface.
An ultrasonic probe characterized by that. The ultrasonic probe according to claim 1,
The ultrasonic probe according to claim 1, wherein the detected member is a member that rotates, and an outer peripheral surface thereof is the detected surface. The ultrasonic probe according to claim 1,
The ultrasonic probe according to claim 1, wherein the detected member is a member that rotates, and a side surface of the detected member is the detected surface. A case having a medium chamber filled with an acoustic medium;
An ultrasonic transducer moving in the medium chamber;
A gear mechanism that is provided in the medium chamber and transmits a motive force to the ultrasonic transducer;
A position detector provided in the medium chamber for detecting a movement position of the ultrasonic transducer;
Including
The position detector is
A magnetic drum that moves with the ultrasonic transducer;
A magnetic sensor having a sensor surface close to and facing the magnetic drum surface in the magnetic drum, and detecting a relative motion of the magnetic drum surface;
Have
An ultrasonic probe, characterized in that an entry restricting means is provided for preventing the wear powder generated by the gear mechanism from entering the gap between the sensor surface and the magnetic drum surface. The ultrasonic probe according to claim 8,
The ultrasonic probe according to claim 1, wherein the entry restricting means is provided on a wear powder entry side in the gap, and has a member in contact with or close to the magnetic drum surface.

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