JP2007292484A - Linear sensor with guide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small linear sensor with guide facilitating alignment without looseness and precisely detecting a slide position. <P>SOLUTION: In the linear sensor 1 with guide including a slide shaft 2, a sensor head 3 detecting the slide position of the slide shaft, and a guide member 4 guiding the slide shaft, the slide shaft 2 is made into a sensor rod which is nonmagnetic and whose axial center part is made into hollow and in which a magnetic core member 5 and a nonmagnetic member 6 having respective prescribed widths are alternately mounted on its hollow axial center part 21. The sensor head 3 includes a coil part 31. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a linear sensor with a guide that includes a slide shaft, a sensor head that detects a slide position of the slide shaft, and a guide member that guides the slide shaft.

  Conventionally, a linear sensor in which a linear movement mechanism unit and a linear position detection sensor for detecting the movement position are combined is known.

  For this purpose, the linear moving mechanism section is a slide moving section having a slide shaft provided with diamagnetic marks at a predetermined pitch on the surface thereof, and the linear position detecting sensor is connected to the diamagnetic mark portion and the slide shaft. As a slide position detection unit having a slide shaft and a coil formed of a magnetic part of the material, the slide of the slide shaft is detected by detecting a change in magnetic coupling between the diamagnetic mark and the slide shaft magnetic part by the coil. Devices for determining the position are known. In this device, the detection coil is provided in a cylindrical body through which the slide shaft is inserted, and two types of coils, a primary coil and a secondary coil, are provided, and the magnetic coupling between the primary coil and the secondary coil is magnetic. It uses the fact that it changes with the position of the mark. It is also known that the detection coil is a primary / secondary coil.

In order to increase the measurement accuracy and reduce the error, it is important to smooth the operation of the slide shaft, and the guide is performed by a linear guide or the like. For this reason, a slide position detecting device in which a plurality of guide grooves for guiding with a linear guide are provided and the magnetic mark is provided excluding the guide groove portion has already been filed by the present applicant (for example, see Patent Document 1). ).
JP 2003-139563 A (page 1-4, FIG. 1)

  If the slide shaft is provided with a plurality of guide grooves and guided by a linear guide, the slide shaft can be smoothly guided. However, when the magnetic marks are provided on the outer peripheral portion of the slide shaft at a predetermined pitch, a complicated process for removing the groove portion is required.

  When the slide moving unit and the slide position detecting unit are provided, the apparatus is large in a configuration in which they are provided in parallel. Further, if the moving unit and the detecting unit are not coaxial, there is a problem of parallelism between the moving unit and the detecting unit, which may cause Abbe error (parallelism error). In addition, there is a problem that the apparatus becomes longer when the slide moving unit and the slide position detecting unit are simply provided in series.

  Further, in order to reduce the size of a pick-and-place device or the like that incorporates a small electrical component into the apparatus as in the manufacturing site of electrical components, a smaller linear sensor is required. Furthermore, it is desirable that the measurement accuracy be improved so that the measurement accuracy does not deteriorate even if it is repeatedly operated.

  Therefore, there is a need for a slide position detection device having a configuration that can reduce the size of the device, reduce repetition errors, increase accuracy, and reduce weight.

  For this purpose, it is necessary to provide a linear sensor having a magnetic mark that can reduce the size of the slide shaft and the sensor head, facilitate the operation of the slide shaft, and perform high-precision magnetic measurement even when repeatedly sliding.

  In order to solve the above problems, an object of the present invention is to provide a small linear sensor with a guide that is easy to center without a backlash and can detect a highly accurate slide position.

  In order to achieve the above object, an invention according to claim 1 is a linear sensor comprising a slide shaft, a sensor head for detecting a slide position of the slide shaft, and a guide member for guiding the slide shaft, The slide shaft is made non-magnetic and its axial center is hollow, and a sensor rod is constructed by alternately mounting a magnetic core member and a non-magnetic member each having a predetermined width on this hollow shaft center. The sensor head is a magnetic sensor including a coil.

  According to the first aspect of the invention having the above configuration, since the slide shaft itself constitutes the sensor rod, even if the slide moving unit and the slide position detecting unit are configured in series, the lengthening of the apparatus is prevented. The size can be reduced, and centering is easy and measurement errors (Abbe errors) can be suppressed. Furthermore, even if the sliding movement is repeated, the magnetic core member is not worn or damaged, and the lifetime can be increased.

  The invention according to claim 2 is characterized in that the slide shaft is a ball spline shaft having a plurality of guide grooves, and the guide member has ball spline type guide means.

  According to the invention which concerns on Claim 2 which has said structure, a slide movement can be smoothly performed using a guide groove.

  The invention according to claim 3 is characterized in that the guide groove is at least three or more.

  According to the invention of claim 3 having the above-described configuration, since the slide shaft is guided by three or more guide grooves, rattling of the guide grooves is effectively prevented, and even a small and long guide shaft can be accurately prevented. Can be slid.

  The invention according to claim 4 is characterized in that the guide member has linear ball bush type guide means, and the slide shaft is a cylindrical shaft whose surface is hard-plated.

  According to the invention which concerns on Claim 4 which has said structure, a linear ball bush type linear sensor can be comprised using the slide shaft provided with the magnetic core member in the axial center part.

  The invention according to claim 5 is characterized in that the slide shaft is a slide screw, and the guide member has a ball screw type guide means.

  According to the invention which concerns on Claim 5 which has said structure, a ball screw type linear sensor can be comprised using the slide screw provided with the magnetic core member in the axial center part.

  The invention according to claim 6 is characterized in that the slide shaft is an air bearing shaft and the guide member is an air bearing guide.

  According to the invention according to claim 6 having the above-described configuration, it becomes a non-contact type slide shaft, the parts are not consumed, the life can be extended, and high-speed driving is possible.

  The invention according to claim 7 is characterized in that both the magnetic core member and the non-magnetic member are perforated members, and the slide shaft is freely permeable.

  According to the invention of claim 7 having the above-described configuration, the air supply means is connected to the slide shaft and the compressed air is injected from the tip of the slide shaft. It is also possible to apply a suction force to the tip and vacuum-suck the parts using a suction pad attached to the tip.

  According to the present invention, with a guide that uses a non-magnetic, axially hollow shaft center portion, and a sensor rod in which a magnetic core member and a nonmagnetic member each having a predetermined width are alternately mounted on the hollow shaft center portion, as a slide shaft. Since it is a linear sensor, the slide shaft itself constitutes a sensor rod, which can prevent the device from becoming long and downsizing, and even if it repeatedly slides, the magnetic core member will not wear or be damaged, It is possible to obtain a linear sensor with a guide that can extend the life.

  Hereinafter, an embodiment of a linear sensor with guide according to the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view showing the configuration of a linear sensor with guide according to the present invention. 2A and 2B are cross-sectional views of the slide shaft, wherein FIG. 2A shows a slide shaft composed of a spline shaft having a guide groove, and FIG. 2B shows a cylindrical slide shaft having no groove. FIG. 3 is a perspective view showing a specific example of a linear sensor with guide, wherein (a) is a ball spline type linear sensor with guide, (b) is a linear ball bush type linear sensor with guide, (c) is a ball screw type linear sensor with a guide.

  As shown in FIG. 1, a linear sensor 1 with a guide according to the present invention includes a slide shaft 2, a sensor head 3 that detects a slide position of the slide shaft, and a guide member 4 that guides the slide shaft 2. It is. Further, the slide shaft 2 has a non-magnetic main body, and the shaft center is hollow. Further, a sensor rod having magnetic core members 5 (5a, 5b, 5c, 5d) and non-magnetic members 6 (6a, 6b, 6c) each having a predetermined width mounted alternately on the hollow shaft portion 21.

  Further, the sensor head 3 is a magnetic sensor having a coil portion 31 on the inner periphery thereof, and detects the magnetic inductive coupling that changes due to the movement of the slide shaft 2 that slides inside the sensor head 3, whereby the slide A linear sensor capable of measuring the absolute position of the shaft 2 is configured. Reference numeral 7 denotes a sensor cable.

  Therefore, although the said coil part 31 is made into the coil part which combined the primary coil and the secondary coil, the primary / secondary coil part may be sufficient.

  The guide member 4 is a member provided with guide means 41 for permitting and holding the slide shaft 2 at its inner periphery, and as will be described later, a ball spline type, a linear ball bush type, a ball screw type, and the like. The guide means 41 can be configured as a ball spline type guide member 4A, a linear ball bush type guide member 4B, and a ball screw type guide member 4C, respectively.

  FIG. 2 shows a cross section of the slide shaft 2 incorporating the magnetic core member 5 (5a, 5b, 5c, 5d). FIG. 2 (a) shows a slide shaft 2A composed of a spline shaft having a guide groove. Yes, (b) is a cylindrical slide shaft 2B having no groove.

  In addition, magnetic core members 5 (5a, 5b, 5c, 5d) and non-magnetic members are alternately mounted on the hollow shaft portions provided so as to pass through the shaft centers of the slide shafts 2A and 2B. .

  Since it is set as the above structures, slide shaft 2A, 2B comprises a sensor rod by itself. With this configuration, the slide moving unit and the slide position detecting unit are coaxially arranged, so that the apparatus can be downsized and no measurement error (Abbe error) occurs. Furthermore, since the magnetic core member 5 and the non-magnetic member 6 are built in the shaft, the magnetic core member is not worn or damaged even if it is repeatedly slid and the life can be increased.

  The slide shaft 2A is a spline shaft having a plurality of guide grooves 22 in the axial direction of the outer peripheral portion thereof, but in the present embodiment, four guide grooves 22 are provided as shown in the figure.

  The guide groove 22 is preferably three or more in order for the slide shaft 2A to slide smoothly without rattling. Further, if the slide shaft 2A is configured to smoothly slide and move, the diameter of the guide shaft 2A can be reduced. Therefore, in this embodiment, four guide grooves 22 are provided to effectively prevent rattling of the guide grooves, and can be accurately slid even with a small guide shaft having a small diameter.

  Further, if the magnetic core member 5 incorporated in the shaft is made of a ferromagnetic material, it is possible to reduce the size of the apparatus because only a smaller member is required. For this reason, in the present embodiment, ferrite that is easy to form, has excellent coercive force, and excellent corrosion resistance is used. Further, it is possible to further reduce the size by using a stronger ferromagnetic material.

  Next, a specific example of the linear sensor with guide will be described with reference to FIG.

  FIG. 3A shows a ball spline type linear sensor 1A with a guide, and a slide shaft 2A (ball spline shaft) having four guide grooves 22 (ball spline grooves) and a sensor head 3 having a coil portion. And a guide member 4A having a ball spline type guide means 41.

  With the above configuration, a small linear actuator can be obtained by sliding in the direction of arrow D1 in the drawing using a drive member that slides (slides) the slide shaft 2A, for example, a linear motor such as a voice coil motor VCM. Therefore, it is possible to easily cope with downsizing and high speed of equipment such as pick and place.

  For example, a linear actuator capable of sliding ± 8 mm at a repetition rate of 3 Hz to 10 Hz with a small diameter of the slide shaft 2A of about 3 to 6 mm can be realized. Also, the position of the linear sensor can be controlled in units of microns.

  FIG. 3 (b) shows a linear sensor 1B with a linear ball bush type guide, and a guide member having a cylindrical slide shaft 2B, a sensor head 3 having a coil portion, and a linear ball bush type guide means 41. 4B.

  With this configuration, the slide shaft 2B may be simply cylindrical. However, if the outer periphery of the linear ball bushing type guide member 4B in contact with the ball surface is hard-plated to provide wear resistance, durability is improved. Is preferable. It is also possible to use a nonmagnetic stainless steel rod that is wear resistant and durable.

  FIG. 3C shows a ball screw type linear sensor 1C with a guide, which includes a screw-like slide shaft 2C, a sensor head 3 having a coil portion, and a guide member 4C having a ball screw type guide means 41. It is a configuration.

  If it is this structure, the small linear actuator which implement | achieves the sliding movement of the arrow D1 direction in the figure and the rotational movement of the arrow D2 direction can be obtained using the drive motor which rotationally drives the slide shaft 2C. Alternatively, it may be a linear sensor that goes straight while rotating.

  Furthermore, it is possible to construct a small unit that can rotate and move the slide shaft by using an air bearing type guide member (not shown). Units can be built.

  Also, as shown in FIG. 4, the magnetic core member is a perforated magnetic core member 5 </ b> A having a through hole 50, and the nonmagnetic member is a perforated nonmagnetic member 6 </ b> A having a through hole 60, so that air can be freely passed. It becomes the linear sensor 1 with a guide provided with a slide shaft.

  Therefore, a suction force can be applied to the hollow hole by the suction pump P connected to the slide shaft, and for example, the parts can be vacuum-sucked through the suction pad 22 attached to the tip of the slide shaft.

  With the above configuration, it is possible to construct a high-precision Z / θ axis unit that can be controlled in micron units by directly driving the slide shaft via the drive member 10 and accurately at a predetermined position on the substrate. It can be applied to a pick and place apparatus that repeatedly arranges parts.

  Furthermore, since it is a non-contact type slide shaft, no lubricant or the like is required, parts are not consumed, the life can be extended, and high-speed rotation is also possible.

  Further, since no lubricant is used, a linear sensor or a small linear actuator that can be operated even under high-temperature working conditions can be configured.

  As described above, according to the present invention, in the linear sensor including the slide shaft, the sensor head that detects the slide position of the slide shaft, and the guide member that guides the slide shaft, the non-magnetic shaft member is hollow. Since the sensor rod having a configuration in which a magnetic core member and a non-magnetic member each having a predetermined width are alternately mounted on the shaft center portion is a linear sensor with a slide shaft, the slide shaft itself constitutes the sensor rod, and the device Therefore, it is possible to reduce the size of the device. It is also possible to easily provide a through hole for vacuum suction.

  Furthermore, since the magnetic core member is built in the shaft, it is possible to obtain a linear sensor with a guide capable of extending the life without causing the magnetic core member to be worn or damaged even when repeatedly slid. it can.

It is sectional drawing which shows the structure of the linear sensor with a guide which concerns on this invention. It is sectional drawing of a slide axis | shaft, (a) shows the slide axis | shaft which consists of a spline axis | shaft provided with a guide groove, (b) has shown the cylindrical slide axis | shaft which does not have a groove | channel. It is a perspective view which shows the specific example of a linear sensor with a guide, (a) is a linear sensor with a guide of a ball spline type, (b) is a linear sensor with a guide of a linear ball bush type, (c) is This is a linear sensor with a ball screw type guide. It is sectional drawing which shows another embodiment of the linear sensor with a guide which concerns on this invention.

Explanation of symbols

1 Linear sensor with guide 1A Linear sensor with guide of ball spline type 1B Linear sensor with guide of linear ball bushing type 1C Linear sensor with guide of ball screw type 2 Slide shaft 3 Sensor head 4 Guide member 4A Guide member of ball spline type 4B Linear ball bushing type guide member 4C Ball screw type guide member 5 Magnetic core member 6 Nonmagnetic member 21 Hollow shaft center part 22 Guide groove 31 Coil part 41 Guide means

Claims (7)

A linear sensor comprising a slide shaft, a sensor head for detecting a slide position of the slide shaft, and a guide member for guiding the slide shaft,
The slide shaft is made non-magnetic and its axial center is hollow, and a sensor rod is configured by alternately mounting a magnetic core member and a non-magnetic member of a predetermined width on the hollow shaft center, respectively. A linear sensor with a guide, wherein the sensor head is a magnetic sensor having a coil.   2. The linear sensor with guide according to claim 1, wherein the slide shaft is a ball spline shaft having a plurality of guide grooves, and the guide member has ball spline type guide means.   The linear sensor with guide according to claim 2, wherein the guide groove is at least three or more.   2. The linear sensor with guide according to claim 1, wherein the guide member has a guide means of a linear ball bush type, and the slide shaft is a cylindrical shaft whose surface is hard-plated.   2. The linear sensor with guide according to claim 1, wherein the slide shaft is a slide screw, and the guide member has a ball screw type guide means.   The linear sensor with guide according to claim 1, wherein the slide shaft is an air bearing shaft, and the guide member is an air bearing guide.   The linear sensor with guide according to claim 1, wherein both the magnetic core member and the nonmagnetic member are perforated members, and the slide shaft is air permeable.

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