JP2010025888A - Linear gauge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear gauge having further improved low friction properties. <P>SOLUTION: A linear ball bearing 35 is fixed to a frame 31 while a shaft 34 in which a measuring probe 32 and a contacting pin 33 are fixed to both the ends is being inserted. A base 361 of a linear ball slider 36 is fixed to the frame 31 so that the linear movement direction of a slider 362 is in the axial direction of the shaft 34. Also, an energization unit 37 is fixed to the frame 31 to energize a slit holder 372 fixed onto the upper surface of the slider 362 in the direction of the side of the measuring probe of the shaft 34 by a spring 373, and hence maintains contact between one end of the slit holder 372 and the contacting pin 33 at the tip in the axial direction of the shaft 34 regardless of the displacement of the shaft 34. Then, a slit plate 38 for detecting displacement is fixed to the upper surface of the slit holder 372 displaced in the axial direction of the shaft 34 in linking with the shaft 34 in this manner. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a linear gauge that measures a displacement in a linear motion direction of an object to be measured.

  In a linear gauge, as a structure for supporting a shaft provided with a probe at the tip, there is a structure for supporting the shaft in a slidable manner (for example, Patent Document 1) or a structure for supporting the shaft using a linear ball bearing. Known (for example, Patent Document 2). Here, in the linear gauge described in Patent Document 2, a moving member having a tapered portion that slides on the end opposite to the probe side end of the shaft is provided, and is generated in accordance with the displacement of the shaft of the moving member. By detecting the displacement, the displacement of the shaft is detected.

Further, as a technique for detecting displacement in a linear gauge, a technique for detecting displacement of a shaft from reflected light or transmitted light of light irradiated on a slit plate fixed to the shaft is also known (for example, Patent Document 3). .
Japanese Patent Laid-Open No. 2003-28602 JP-A-8-278121 JP 2000-193491 A

The structure in which the shaft that is linearly moved according to the displacement of the object to be measured is supported by using a linear ball bearing is preferable in terms of improving measurement accuracy because it is excellent in low friction as compared with the structure in which the shaft is slidably supported.
However, the linear ball bearing uses a slit plate fixed to the shaft as described in Patent Document 3 in order to allow a rotational motion about the linear motion direction as well as a linear motion relative to the shaft. When detecting displacement, the slit plate is rotated together with the shaft, and normal displacement detection is hindered. On the other hand, when a moving member having a tapered portion that slides with the end of the shaft is provided as in Patent Document 2, the measurement accuracy deteriorates due to friction caused by the sliding.

  Then, this invention makes it a subject to provide the linear gauge excellent in the low friction property.

  In order to achieve the above object, the present invention provides a linear gauge for measuring a uniaxial displacement of an object to be measured, a frame, a linear ball bearing fixed to the frame, and a probe at one end against the other end. A shaft that is supported by the linear ball bearing so as to be linearly movable, a base that is fixed to the frame, and a uniaxial direction with respect to the base that is supported by the base via a rolling bearing. A slide member that moves linearly, a gauge that is fixed to the slide member, a biasing member that biases the slide member, and a movement detector that detects the movement of the gauge in the uniaxial direction in a non-contact manner. The sliding member is in contact with the abutting portion of the shaft in the uniaxial direction by the urging force of the urging member, and the shaft is maintained while maintaining the abutting. It is obtained so as to displace in the axial direction along with the axial direction of the displacement of the bets.

  According to such a linear gauge, while the shaft is supported by the linear ball bearing so as to be linearly movable, the gauge is supported by the base and the slide member supported by the base via the rolling bearing so as to be linearly movable. Is interlocked with the shaft so as to move in one axial direction. That is, since the linear motion of each part is realized by a mechanism using a rolling bearing, it is possible to realize excellent low friction with respect to the linear motion of each part. Also, the shaft and the gauge are not fixed, and the uniaxial linear movement of both is realized only by the contact of the shaft and the slide member with the gauge fixed in the uniaxial direction. Therefore, even if the shaft rotates around the axis of the shaft, this rotation is not transmitted to the slide member, and the gauge fixed to the slide member does not rotate.

Therefore, it is possible to detect displacement normally while maintaining low friction.
In this linear gauge, the slide member is composed of a slider that moves linearly with respect to the base supported on the base via a rolling bearing, and a gauge holder that is fixed to the slider. The gauge is fixed to the gauge holder, the biasing member is a spring having one end fixed to the frame and the other end connected to the gauge holder, and the abutting portion is uniaxial with the gauge holder. You may comprise so that it may contact | abut to a direction.

  As described above, according to the present invention, it is possible to provide a linear gauge that is more excellent in low friction.

Embodiments of the present invention will be described below.
FIG. 1a shows an exploded view of the linear gauge according to this embodiment, and FIG. 1b shows an assembly view of the linear gauge.
As shown in the figure, the linear gauge is roughly composed of a detection block 1, a connecting stay 2, a movable mechanism block 3, and a case 4.
The detection block 1 includes a light projecting block 11 and a light receiving measurement block 12. The light projecting block 11 is configured by assembling an LED 112 and a lens 113 to an optical holder 111 using a spacer 114 and a fixed lid 115. The light receiving measurement block 12 is configured by fixing a fixing holder 123 with a fixing slit plate 122 to a circuit board 121 on which a light receiving element and a signal processing circuit are mounted with screws 124. Further, the entire detection block 1 is integrated by fixing the optical holder 111 to the circuit board 121 together with the screw 124. Here, the optical holder 111 has a shape in which a gap is generated between the fixed slit plate 122 and the lens 113 fixed to the optical holder 111 while being fixed to the circuit board 121. The emitted light sequentially passes through the lens 113, the gap between the fixed slit plate 122 and the lens 113, and the fixed slit plate 122, and enters the light receiving element of the circuit board 121.

  Next, the movable mechanism block 3 includes a frame 31, a shaft 34 having a measuring element 32 at one end and a contact pin 33 fixed at the other end, and a high precision such as a miniature stroke bearing that guides the linear movement of the shaft 34. Linear ball bearing 35, linear ball slide 36 that is a linear guide using the ball bearing, urging unit 37, slit plate 38, O-ring 39, and fixing screw 40.

  The linear ball bearing 35 is fixed to the frame 31 via the dust-proof hermetic O-ring 39 with the shaft 34 having the measuring element 32 and the contact pin 33 fixed at each end. The shaft 34 is assembled to the frame 31 so as to be linearly movable in the axial direction of the shaft 34. The linear ball bearing 35 is also provided with a stopper for preventing the shaft 34 from falling off the linear ball bearing 35.

  Here, the linear ball slide 36 is supported by the base 361 via a base 361 and a ball bearing incorporated in the base 361 as shown in FIG. 2a1, and linearly moves with respect to the base 361 as shown in FIG. 2a2. And a slider 362. Note that the base 361 is also provided with a stopper for preventing the slider 362 from falling off the base 361. In such a linear ball slide 36, the slider 362 may be supported on the base 361 by another rolling bearing such as a roller bearing.

  Further, as shown in FIG. 2b1, the urging unit 37 has an anchor portion 371, a slit holder 372, and a spring 373 that couples the anchor portion 371 and the slit holder 372. As shown in FIG. The slit holder 372 is provided so as to be movable with respect to the anchor portion 371 in a state in which the slit holder 372 is biased in the direction of the anchor portion by the spring 373.

As shown in FIG. 1 a, the slit plate 38 is fixed to the upper surface of the slit holder 372 of the biasing unit 37 using an adhesive or the like, and the slit holder 372 of the biasing unit 37 is a slider of the linear ball slide 36. The upper surface of 362 is fixed using an adhesive or the like.
As shown in FIG. 2 c 1, the base 361 of the linear ball slide 36 is arranged so that the linear movement direction of the slider 362 of the linear ball slide 36 is the axial direction of the shaft 34 assembled to the frame 31 as described above. The frame 31 is fixed by a fixing screw 40. Further, the base 361 of the linear ball slide 36 has a linear movement direction of the contact pin 33 at the tip of the shaft 34 and the slit holder 372 fixed to the slider 362 in a state where the shaft 34 is moved to the measuring element 32 by the maximum amount. One end of the slider 34 abuts in the axial direction of the shaft 34, and from this state, the slider 362 and the slit holder 372 can linearly move in the end direction opposite to the one end abutted on the abutting pin 33. Thus, the frame 31 is fixed. Further, the anchor portion 371 of the urging unit 37 is fixed to the frame 31 on the probe 32 side of the shaft 34 with respect to the linear ball slide 36 so that the contraction direction of the spring 373 becomes the probe side direction of the shaft 34. 40 is fixed.

  As a result, as shown in FIGS. 2 c 1 and c 2, the slit holder 372 of the urging unit 37 is moved together with the slit plate 38 by the urging force of the spring 373 in conjunction with the axial movement of the shaft 34. It moves in the axial direction of the shaft 34 while maintaining the contact. On the other hand, since the contact pin 33 and the slit holder 372 are not fixed, even if the shaft 34 rotates around the axis of the shaft 34, the slit holder 372 and the slit plate 38 do not rotate accordingly. The angle of the slit plate 38 around the axis of the shaft 34 is kept constant.

Now, referring back to FIG. 1, the entire linear gauge is integrally formed by connecting the frame 31 of the movable mechanism block 3 and the optical holder 111 of the detection block 1 by the connecting stay 2 and housing the case in the case 4. The
In addition, as shown in FIGS. 3A and 3B, the gap between the frame 31 of the movable mechanism block 3 and the detection block 1 is such that a part of the slit plate 38 is in the gap between the fixed slit plate 122 and the lens 113 described above. Inserted and set so that the slit plate 38 linearly moves between the fixed slit plate 122 and the lens 113 as the shaft 34 moves linearly.

Here, the slit plate 38 is provided with a plurality of slits, and the role of the gauge is obtained by spatially encoding light transmitted through the slit plate 38 in accordance with the amount of displacement of the slit plate 38. Fulfill. The fixed slit plate 122 expresses light that is spatially encoded by the slit plate 38 and then passes through the fixed slit plate 122. The displacement amount of the slit plate 38 is expressed by intensity, and the moving direction of the slit plate 38 is expressed by phase. A plurality of slits are provided for decoding light.
The signal processing circuit mounted on the circuit board 121 detects the light emitted from the LED 112 and transmitted through the slit plate 38 and the fixed slit plate 122 by the light receiving element. Detect the moving direction.
Therefore, according to the configuration as described above, when the probe 32 is brought into contact with the measurement object, the slit plate 38 follows the axial displacement of the shaft 34 at the contact point of the measurement object with the measurement element 32. Is displaced in the axial direction of the shaft 34, and this displacement is measured by a signal processing circuit mounted on the circuit board 121.

The embodiment of the present invention has been described above.
As described above, according to this embodiment, the slit plate 38 is supported by the linear ball slide 36 so as to be linearly movable while the shaft 34 is supported by the linear ball bearing 35 so as to be linearly movable. That is, since the linear motion of each part is realized by a mechanism using a rolling bearing such as a ball bearing or a roller bearing, it is possible to realize excellent low friction with respect to the linear motion of each part. Further, the shaft 34 and the slit plate 38 are not fixed, and the uniaxial movement of both is realized only by the contact between the contact pin 33 of the shaft 34 and the slit holder 372. Even if 34 rotates around the axis of the shaft 34, this rotation is not transmitted to the slit holder 372, and the slit plate 38 fixed to the slit holder 372 does not rotate. Therefore, it is possible to detect displacement normally while maintaining low friction.

It is a figure which shows the structure of the linear gauge which concerns on embodiment of this invention. It is a figure which shows typically the movable mechanism of the linear gauge which concerns on embodiment of this invention. It is a figure which shows the structure of the measurement of the linear gauge which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Detection block, 2 ... Connection stay, 3 ... Movable mechanism block, 4 ... Case, 11 ... Light emission block, 12 ... Light reception measurement block, 31 ... Frame, 32 ... Measuring element, 33 ... Contact pin, 34 ... Shaft 35 ... Linear ball bearing, 36 ... Linear ball slide, 37 ... Biasing unit, 38 ... Slit plate, 39 ... O-ring, 40 ... Fixing screw, 111 ... Optical holder, 112 ... LED, 113 ... Lens, 114 ... Spacer 115, fixed lid, 121, circuit board, 122, fixed slit plate, 123, fixed holder, 124, screw, 361, base, 362, slider, 371, anchor portion, 372, slit holder, 373, spring.

Claims (2)

A linear gauge that measures the displacement in one axis direction of the measured object,
Frame,
A linear ball bearing fixed to the frame;
A shaft having a measuring element at one end and a contact portion at the other end, and supported by the linear ball bearing so as to be linearly movable;
A base fixed to the frame;
A sliding member that linearly moves in the uniaxial direction with respect to the base supported by the base via a rolling bearing;
A gauge fixed to the slide member;
A biasing member for biasing the slide member;
A movement detector for detecting the movement of the gauge in the uniaxial direction without contact;
The sliding member is in contact with the abutting portion of the shaft in the uniaxial direction by the urging force of the urging member, and the uniaxial direction is accompanied by the uniaxial displacement of the shaft while maintaining the abutting. A linear gauge characterized by displacement.
The linear gauge according to claim 1,
The slide member is
A slider that moves linearly with respect to the base supported by a rolling bearing on the base;
It is composed of a gauge holder fixed to the slider,
The gauge is fixed to the gauge holder,
The biasing member is a spring having one end fixed to the frame and the other end connected to the gauge holder,
The linear gauge, wherein the contact portion is in contact with the gauge holder in the uniaxial direction.