Displacement measuring device, and device having a moving body

Abstract

The encoder, which has a wire component, accurately outputs a signal regarding the displacement of the moving object being measured, based on the wire component inside the outer cable, which offers a high degree of freedom in routing and is not affected by the measurement environment of the object being measured. [Solution] The displacement measuring device includes an encoder that outputs a signal corresponding to the displacement of the moving body based on the extension and retraction of the wire member from the extension portion, and an outer cable from which the wire member is extended and retracted, with the other end fixed to the extension portion of the encoder.

Description

Technical Field

[0004] , ,

[0001] The present invention relates to a displacement measuring device and a device having a moving body.

Background Art

[0002] Conventionally, as shown in FIG. 6, a measuring device using an encoder 100 that measures displacement by pulling out a wire rope 101 is known. For example, in a machine tool, the amount of movement of a moving body is counted by the encoder 100 and its position is calculated (for example, Patent Document 1). Also, although not shown, a position calculation method is also known in which the pulling distance of the wire rope 101 drawn from an encoder provided in a propulsion excavator is counted to detect the position of the excavator (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a device having a structure in which the wire rope 101 is pulled out (retracted) in this way, in order to prevent damage to the housing 102 and the wire rope 101 due to repeated movement in a state where the wire rope 101 is in contact, the entrance and exit of the wire rope 101 and the moving body are arranged linearly so that the wire rope 101 can be pulled out straight. Therefore, when the positions of the device body 104 of the encoder 100 and the moving body cannot be arranged linearly, the wire rope 101 is routed (passed) using a pulley 103 or the like, and the pulling position is moved so that the tip 101a of the wire rope 101 can be pulled out straight with respect to the moving body and used.

[0005] However, since the pulled-out wire rope 101 is held in an exposed state along the routing path, the part that comes into contact with the pulley 103 may damage the wire rope 101. In addition, if the moving object moves with foreign matter attached to the wire rope 101, the wire rope 101 may break or snap.

[0006] In particular, when used in conventional tunneling excavators such as the one disclosed in Patent Document 2, the encoder is used in a tunneling machine where the encoder is installed in the ground. In this case, the wire rope 101 is used in an exposed state under poor measurement conditions such as dust and sand being blown around, so foreign matter such as dust and sand easily adheres to the wire rope 101, and a problem arises in which the wire rope 101 is cut due to contact between the wire rope 101 and the pulley 103.

[0007] Furthermore, under the measurement conditions described above, if the wire rope 101 is made of steel, for example, rust and damage are likely to occur on the wire rope 101. Even if it is greased for rust prevention, there is a concern that sand and dust will easily adhere to the grease under such measurement conditions. In this case, the sand and dust adhering to the grease will act like sandpaper on the wire rope 101 and damage it, resulting in the need to replace the wire rope 101 for maintenance, which would necessitate suspending the measurement of the movement of the moving object. In addition, if the path of the wire rope 101 is changed using a pulley 103, etc., there will be restrictions on the installation position of the pulley 103, etc. and the range of the path, so the degree of freedom in routing the wire rope 101, etc. is low.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a displacement measuring device and a device having a movable object, which allows the entrance to be easily moved to a location where the wire rope can be pulled straight out relative to the moving object of measurement, by passing a wire member through an outer cable when it is not possible to pull the wire rope straight out relative to the moving object of measurement. Furthermore, the present invention aims to provide a displacement measuring device and a device having a movable object, which can output a signal corresponding to the displacement of the moving object of measurement, based on a wire member in an outer cable that has a high degree of freedom in routing and is not affected by the measurement environment of the object of measurement, using an encoder having a wire member. [Means for solving the problem]

[0009] The displacement measuring device according to the present invention comprises an encoder that outputs a signal corresponding to the displacement of the moving body of a measuring object having a wire member, one end of which is pulled out from a pull-out section and the other end of which is fixed to the moving body of the measuring object having a moving body, and an outer cable from which the one end of the wire member is pulled out and the other end is positioned on the pull-out section side of the encoder, and through which the wire member is passed to move back and forth.

[0010] In one embodiment of the present invention, a coupling is provided for fixing one end of the outer cable to a fixed part that is fixed to the moving body.

[0011] In another embodiment of the present invention, the outlet portion is provided with a coupling for securing the other end of the outer cable.

[0012] In yet another embodiment of the present invention, the portion of the wire member extending from one end of the outer cable fixed to the coupling toward the moving body is further provided with at least one of a debris-proof portion and an oil-lubricating portion of the wire member.

[0013] In yet another embodiment of the present invention, a protective member is further provided that covers the wire member from one end of the outer cable fixed to the coupling to the movable body.

[0014] In yet another embodiment of the present invention, a protective member is further provided, which is located on the outside of the outer cable and is attached to the end of the outer cable to maintain the straightness of the outer cable. [Effects of the Invention]

[0015] According to the present invention, when it is not possible to pull a wire rope straight out relative to the moving object being measured, by passing a wire member through the outer cable, the entrance can be easily moved to a location where the wire rope can be pulled straight out relative to the moving object being measured. Furthermore, a signal regarding the displacement of the moving object being measured can be output by an encoder having a wire member, based on the wire member inside the outer cable, which offers a high degree of freedom in routing and is not affected by the measurement environment of the object being measured. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram illustrating a displacement measuring device according to the first embodiment of the present invention. [Figure 2] This is a schematic diagram illustrating the end portion of the outer cable of the displacement measuring device. [Figure 3] This is an explanatory diagram illustrating the schematic internal configuration of the encoder in the displacement measuring device. [Figure 4] This is a schematic diagram illustrating a displacement measuring device according to a second embodiment of the present invention. [Figure 5] This is a schematic diagram illustrating a displacement measuring device according to a third embodiment of the present invention. [Figure 6] This is an explanatory diagram illustrating the main components of a conventional displacement measuring device. [Modes for carrying out the invention]

[0017] Hereinafter, with reference to the attached drawings, a displacement measuring device and a device having a moving body according to an embodiment of the present invention will be described in detail. However, the following embodiments do not limit the invention according to each claim, and not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0018] Also, in the following embodiments, the same or corresponding components are denoted by the same reference numerals and redundant descriptions are omitted. Also, in the embodiments, when the arrangement, scale, dimensions, etc. of each component are exaggerated or minimized and shown in a state inconsistent with the actual ones, and when the description of some components is omitted and shown.

[0019] [First Embodiment] FIG. 1 is an explanatory diagram schematically showing a displacement measuring device according to a first embodiment of the present invention. FIG. 2 is an explanatory diagram schematically showing a terminal portion of an outer cable of the displacement measuring device. FIG. 3 is an explanatory diagram schematically showing an internal configuration of an encoder of the displacement measuring device.

[0020] As shown in FIG. 1, the displacement measuring device 1 of the first embodiment can be applied, for example, to output a signal corresponding to the displacement of a machine tool 2 including, as a device having a moving body which is a measurement object, an excavator for excavation work, a wood processing machine for wood precutting, and a jack machine for civil engineering work and bridge construction work. The displacement measuring device 1 can be configured to include, for example, a wire drawing type encoder 40 (for example, a rotary encoder) having an inner wire 11 which is a wire member, and an outer cable 30 through which the inner wire 11 can move forward and backward inside. A displacement measurement system can be configured by this displacement measuring device 1 and a control unit 20. <>

[0021] The inner wire 11 of the encoder 40 is made of, for example, a steel wire with a diameter of approximately 0.45 mm to approximately 1.5 mm in width. One end of the inner wire 11 is pulled out from the outlet bush 3a (see Figure 3), which is the exit part of the encoder 40, to the outside of the housing 40a. A hook 12 is provided at one end of the inner wire 11. One end of the inner wire 11 is fixed to the machining head 2b, which is the moving part of the machine tool 2, via the hook 12. The inner wire 11 has a first end portion 11a of a predetermined length (for example, approximately 10 mm to approximately 1,000 mm) including one end of the inner wire 11. The first end portion 11a of the inner wire 11 is fixed to the machining head 2b along the direction of the arrow (direction of movement) in the figure.

[0022] The outer cable 30 is positioned, for example, between the encoder 40 and the machine tool 2, with the inner wire 11 passing through it so as to be able to move back and forth. In other words, in the first embodiment, one end of the outer cable 30 is positioned on the housing 2a side, which is the fixed part of the machine tool 2. The other end of the outer cable 30 is positioned on the coupling support base 3 (see Figures 1 and 3) side, which is provided with an outlet bush 3a, which is the exit part of the encoder 40.

[0023] The outer cable 30 has, for example, a second end 37a of a predetermined length (for example, about 30 mm to about 50 mm) at one end. The outer cable 30 also has, for example, a third end 37b of a predetermined length (for example, about 30 mm to about 50 mm) at the other end. The second end 37a of the outer cable 30 is arranged coaxially with the first end 11a of the inner wire 11. The third end 37b of the outer cable 30 is arranged on the coupling support base 3 side where the outlet bush 3a is provided, along the direction in which the inner wire 11 is pulled out of the outlet bush 3a.

[0024] The outer cable 30 has cup members 38a and 38b attached to the tip portions of the second end 37a and third end 37b, respectively, each having a hole 29 (see Figure 2) in its center through which the inner wire 11 can be inserted. The outer cable 30 is elastically deformable and flexible. Furthermore, the outer cable 30 has higher strength and toughness than the inner wire 11.

[0025] In the first embodiment, the outer cable 30 is connected and fixed to the encoder 40 and the machine tool 2 via couplings 39a and 39b, to which the cup members 38a and 38b are respectively connected. In this embodiment, the length of the cup member 38a and coupling 39a in the extension direction of the outer cable 30 is longer than that of the cup member 38b and coupling 39b. For this reason, the cup member 38a and coupling 39a are positioned on the outside of the outer cable 30 and function as protective members that maintain the straightness of the outer cable 30 at the third end 37b of the outer cable 30. The cup member 38b and coupling 39b, together with the fixing member 7 described later, maintain the linearity of the outer cable 30. Various known coupling mechanisms and joint members can be used for these cup members 38a, 38b and couplings 39a, 39b. Furthermore, in this example, the cup member 38a and coupling 39a on the encoder 40 side are extended, but this structure may also be used for the moving body side such as the machine tool 2, or the encoder 40 side may be the structure for the moving body. The outer cable 30 may also be directly connected and fixed to the portion surrounding the housing 2a and outlet bush 3a without going through the cup members 38a, 38b and couplings 39a, 39b.

[0026] Here, the length of the outer cable 30 can be set to a length that allows for sufficient slack to be laid between the encoder 40 and the machine tool 2 without interfering with on-site work. Any excess length of the outer cable 30 resulting from this slack can be bent into a loop, for example, to avoid affecting the operation of the inner wire 11. In this case, the minimum diameter R of the looped portion is preferably 50 mm or more. Furthermore, the outer cable 30 may be designed to be replaceable to suit various site conditions.

[0027] The couplings 39a and 39b are fixed to coupling support bases 3, for example, which are attached to the housing 40a of the encoder 40 and the housing 2a of the machine tool 2, and have holes (not shown in Figure 1) through which the inner wire 11 can be inserted. The coupling support base 3 on the machine tool 2 side may be fixed to a fixing part such as the housing 2a of the machine tool 2, or to a fixing part such as an installation frame 9, installation base and installation frame (not shown) arranged around the machine tool 2 so that the housing 2a is installed at a work site or the like. The encoder 40 is attached to a member such as a mounting frame 8 arranged around the encoder 40 so that the housing 40a can be attached.

[0028] Near the cup member 38b of the outer cable 30, for example, a U-shaped fixing member 7 is attached to the mounting frame 9 on which the machine tool 2 is installed, to further securely fix the second end 37a of the outer cable 30 as needed. If a shorter cup member 38a and coupling 39b, similar in length to the cup member 38b and coupling 39b, are used on the third end 37b side of the encoder 40, the fixing member 7 may be provided on the mounting frame 8 or the like on the encoder 40 side to ensure the linearity of the third end 37b.

[0029] This fixing member 7 is fastened to the installation frame 9 by, for example, multiple fixing screws 7a. The cable end portion 40b of the displacement measuring device 1 (shown only in Figure 1) includes the first end portion 11a of the inner wire 11, the hook 12, the second end portion 37a of the outer cable 30, and the cup member 38b, and is attached to the machine tool 2 side as described above. Note that the cushioning material such as a rubber cushion provided on the tip side of the first end portion 11a of the inner wire 11 is omitted from the illustration of the cable end portion 40b in Figure 1. Furthermore, the fixing member 7 does not need to be provided if, for example, the cup member 38b and the coupling 39b have the same length as the cup member 38a and the coupling 39a, and the cup member 38b of the outer cable 30 can be fixed to the housing 2a by the coupling support 3 so that the second end portion 37a is coaxial with the first end portion 11a of the inner wire 11. Furthermore, the third end 37b of the outer cable 30 has a structure in which the cup member 38a and coupling 39a are extended longer than those on the second end 37a side, and is therefore positioned along the exit direction of the inner wire 11 at the exit bush 3a.

[0030] In other words, the inner wire 11 needs to be pulled out or rewound straight (perpendicular) with respect to a plane perpendicular to the direction of movement, within a certain range from the coupling support 3 to which the couplings 39a and 39b, which serve as the entry and exit points for the wire, are fixed on the encoder 40 side and the machine tool 2 side (perpendicularity (linearity) is required). Furthermore, on the machine tool 2 side, it needs to be pulled out straight (perpendicular) with respect to the moving machining head 2b as well.

[0031] Therefore, if the inner wire 11 is pulled out or rewound at an angle rather than straight from the coupling support 3, which is provided with the outlet bush 3a, or from the coupling support 3 fixed to the housing 2a, it may scrape the inner wall of the hollow liner portion 31 (see Figure 2) of the outer cable 30, or scrape the outlet bush 3a or the coupling support 3 itself, causing the inner wire 11 to malfunction or break, which may result in unstable or impossible signal output from the encoder 40.

[0032] To prevent this, for example, in order to ensure the verticality of the inner wire 11 within a certain range, it is desirable that the minimum required lengths of the second end 37a and third end 37b of the outer cable 30 be set to, for example, 30 mm or more on the machine tool 2 side, the length L2 from the surface of the coupling support 3 to the end of the fixing member 7 on the encoder 40 side, and the length L1 of the coupling 39a on the encoder 40 side (see Figures 1 and 3). In this way, the lengths L1 and L2 are set to 30 mm or more within a certain range (that is, the length of the outer cable 30 in the extension direction of the second end 37a and the third end 37b is ensured to be 30 mm or more), so that the verticality (linearity) of the inner wire 11 can be ensured on both the encoder 40 side and the machine tool 2 side.

[0033] Furthermore, within the housing 2a of the machine tool 2, the inner wire 11 is exposed between the coupling support 3 to which the second end 37a of the outer cable 30 is fixed and the machining head 2b. However, if the inside of the housing 2a is isolated from the external measurement environment, then even without protection by the outer cable 30, it will not be affected by sand, dust, etc. Also, the outer cable 30 may be arranged so that, for example, at the base end of the cable on the encoder 40 side, the base end is directly connected to the housing 40a and extends without going through the cup member 38a, coupling 39a, and coupling support 3. In this case, the opening through which the inner wire 11 enters and exits the encoder 40 can be substantially located at the end of the outer cable 30 (for example, on the cable tip 40b side), so measures to eliminate the influence of the measurement environment on the inner wire 11 on the encoder 40 side (for example, fixing by connecting the cup member 38a and coupling 39a) become unnecessary.

[0034] [Outer cable configuration] As shown in Figure 2, the outer cable 30 is configured to include, for example, a hollow liner portion 31 through which the inner wire 11 is slidably passed, and a sheath portion 35 that covers the outside of the hollow liner portion 31, extending from the center of the cable outwards. The sheath portion 35 is configured to have higher strength and toughness than the inner wire 11. The sheath portion 35 has a three-layer structure (multilayer structure) that combines, for example, a spiral wire portion 32 which is a spiral steel strip portion, a mesh sleeve portion 33 which is a mesh braided portion, and an outer tube portion 34. The outer cable 30 is exemplified as having a four-layer structure, which is the sum of the one layer of the hollow liner portion 31 and the three layers of the sheath portion 35, but a cable member formed with more layers may also be used.

[0035] The hollow liner portion 31 is made of, for example, a resin material and has an internal space 36 that allows the inner wire 11 to move back and forth inside with sufficient clearance. A polyethylene liner member is placed in the portion of the hollow liner portion 31 that contacts the inner wire 11 and constitutes the internal space 36, to improve sliding properties with the inner wire 11. This internal space 36 may be filled with a lubricating and protective material such as grease. The spiral wire portion 32 of the sheath portion 35 is made of, for example, a thin or flat steel material that is bendable and is spirally wound around the outer circumference of the hollow liner portion 31.

[0036] The mesh sleeve portion 33 of the sheath portion 35 is formed into a cylindrical shape by weaving a material such as carbon fiber yarn, which has high heat resistance and high strength, into a mesh pattern, and is arranged on the outer circumference of the spiral wire portion 32 as a shell structure. The outer tube portion 34 of the sheath portion 35 is formed into a cylindrical shape by molding a highly durable material such as synthetic resin, and is arranged on the outer circumference of the mesh sleeve portion 33.

[0037] Furthermore, the ends of the second end 37a and the third end 37b of the outer cable 30 are cut in a direction intersecting the extension direction of the outer cable 30. When cutting, it is expected that the cut surface (edge ​​portion) of the spiral wire portion 32 in the sheath portion 35 will become burrs, and the internal space 36 of the hollow liner portion 31 will be temporarily crushed. However, a separate shaping process is performed to post-process the internal space 36 so that it becomes circular.

[0038] Furthermore, to prevent burrs on the spiral wire section 32 from interfering with and damaging the inner wire 11, cup members 38a and 38b, which are fixed to couplings 39a and 39b, are attached to the end portion of the outer cable 30 as shown by the arrows in the figure. Burrs on the spiral wire section 32 are caught in the recesses 38c of these cup members 38a and 38b. By attaching the cup members 38a and 38b to the end portion of the outer cable 30 in this way, the spiral wire section 32 of the outer cable 30 and the inner wire 11 are isolated from each other without interfering with each other.

[0039] Even if the environment in which the machine tool 2 is located is poor, for example, one with high temperature and humidity, significant vibration, dust and dirt flying around and falling objects occurring, and the measurement environment by the encoder 40 is consequently poor, the outer cable 30, as described above, possesses flexibility and higher strength and toughness than the inner wire 11, so as not to hinder the movement of the inner wire 11 moving back and forth inside and to reliably protect it, and the output of the signal corresponding to the displacement by the encoder 40 can be completely unaffected by the environment.

[0040] Furthermore, as described above, the outer cable 30 can be bent into a loop or otherwise positioned freely between the encoder 40 and the machine tool 2, thereby significantly improving the flexibility of routing the inner wire 11. The margin of error in the bending angle of the outer cable 30 is set to a level that does not come into contact with the clearance obtained based on, for example, the diameter of the internal space 36 of the hollow liner portion 31 (inner diameter of the outer cable 30) and the diameter (thickness) of the inner wire 11.

[0041] As shown in Figure 3, the encoder 40 is positioned on the other end of the inner wire 11. The encoder 40 has an outlet bush 3a in its housing 40a, which serves as a pull-out section for the inner wire 11. The inner wire 11 is inserted into and removed from the outlet bush 3a. Inside the housing 40a, the encoder 40 includes, for example, a wire drum 41, a rotation detection slit plate 44, an optical sensor 46, and a waveform shaping circuit 47. The other end of the inner wire 11, one end of which is fixed to the processing head 2b, is fixed to the wire drum 41.

[0042] The wire drum 41 rotates around a rotating shaft 42 supported by bearings 43a and 43b. The wire drum 41 is rotationally biased by a spring mechanism 45 attached to the rotating shaft 42 so that the inner wire 11 is unwound with a constant torque. The inner wire 11 is sequentially pulled out and unwound one turn at a time along the axial direction of the rotating shaft 42 by a known wire guide mechanism (not shown) so as not to overlap the wire drum 41 in the circumferential direction.

[0043] The rotation detection slit plate 44 is fixed to the wire drum 41 so as to be synchronously rotatable. The rotation detection slit plate 44 can be made of a known slit plate for encoders, in which concentric slits are formed on a disc. The optical sensor 46 detects the amount of rotation of the rotation detection slit plate 44 by turning the light on and off by the slits and outputs an electrical signal to the waveform shaping circuit 47. The waveform shaping circuit 47 converts the input electrical signal into a pulse signal and outputs it.

[0044] As a result, the encoder 40 is configured to output a signal corresponding to the displacement of the machining head 2b of the machine tool 2 in the direction of the arrow in the figure, based on the insertion and removal of the inner wire 11 from the exit bush 3a. The encoder 40 is also configured to output, for example, a pulse signal corresponding to the displacement of the machining head 2b to the control unit 20, which will be described later.

[0045] Furthermore, in the coupling support base 3 attached to the housing 40a of the encoder 40, the outlet bush 3a provided at the entry and exit points (outlet sections) of the inner wire 11 from the encoder 40 also functions as a buffer for the inner wire 11. This outlet bush 3a is further equipped with a structure that prevents the inner wire 11 from becoming tangled.

[0046] Here, if we define the amount of movement (travel distance) of the processing head 2b as "L" being the amount of inner wire 11 pulled out (feeded out), "D" being the diameter of the wire drum 41, and "r" being the rotation angle of the wire drum 41, then the amount of movement L can be calculated using the following formula (1). L = Π × D × (r / 360) ... (1)

[0047] Furthermore, a control unit 20, which may be electrically connected to the encoder 40, can control the operation of the machine tool 2 based on the output of pulse signals from the waveform shaping circuit 47 of the encoder 40. This control unit 20 may include, for example, a PC device or NC device equipped with a CPU, RAM, ROM, etc., and may be configured to perform calculations and other processing of various information related to the operation control of the machine tool 2.

[0048] The control unit 20 includes a display 21 that displays the above-mentioned information in a way that is visible to, for example, the user of the displacement measuring device 1 or others. Although not shown in the figures, the control unit 20 may also be connected to various input devices (keyboard, mouse, etc.) that accept user input, various output devices (printer, speaker, etc.) that notify the user of the above-mentioned information in addition to the display 21, and various communication devices (mobile terminal, network module, etc.) that can transmit the above-mentioned information. Furthermore, the control unit 20 may be connected to, for example, a digital counter, or the control unit 20 may be configured as an integrated unit with a digital counter.

[0049] Specifically, the control unit 20 calculates the amount of movement (travel distance) of the machining head 2b in the direction of the arrow in the figure by inputting a pulse signal based on the amount of inner wire 11 pulled out (feed-out amount) obtained from the diameter and rotation angle of the wire drum 41 of the encoder 40. The control unit 20 then provides feedback control of the calculation result to the drive device 2c that drives the machining head 2b, thereby controlling the operation of the machining head 2b (for example, movement in the direction of the arrow in the figure).

[0050] In other words, the control unit 20 can control the operation of the machine tool 2 by using the output pulse signal of the encoder 40 as a feedback control signal. In addition, the control unit 20 can calculate the amount of movement of the machining head 2b and, based on the two output pulse signals from the encoder 40, determine the direction of movement of the machining head 2b in accordance with the forward / reverse rotation of the wire drum 41. The information regarding the amount of movement of the machining head 2b based on the calculation results can be used to control the machine tool 2, for example, as a deviation value from a target value, and can be displayed on the display 21 of the control unit 20. The control unit 20 may also be used solely for the purpose of displaying the distance traveled by the machining head 2b on the display 21.

[0051] According to the displacement measuring device 1 of the first embodiment configured in this way, the inner wire 11 of the encoder 40 can be freely positioned and reliably protected between the encoder 40 and the machine tool 2 without hindering its forward and backward movement, thanks to the outer cable 30 which is flexible, has a high degree of freedom in placement, and has higher toughness than the inner wire 11. Furthermore, since the displacement measuring device 1 does not use conventional pulleys or the like, it is easy to install and can be installed at a distance from the encoder 40 while protecting the first end 11a of the inner wire 11.

[0052] Therefore, the encoder 40 can output a signal corresponding to the displacement of the machining head 2b, which can be used as information regarding the amount of movement (displacement) of the machining head 2b of the machine tool 2, by freely routing the inner wire 11 and outer cable 30 between the encoder 40 and the machine tool 2, which are located at different locations, without being affected by the installation environment of the machine tool 2, which is hot, humid, vibrates greatly, and is filled with dust and sand, or the measurement environment of the encoder 40.

[0053] [Second Embodiment] Figure 4 is a schematic diagram illustrating a displacement measuring device according to a second embodiment of the present invention. In the following description, including Figure 4, parts that overlap with those already described in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0054] As shown in Figure 4, the displacement measuring device 1A according to the second embodiment is similar to the displacement measuring device 1 of the first embodiment in that it includes an encoder 40 and an outer cable 30. However, on the machine tool 2 side, the inner wire 11 from one end (second end 37a side) of the outer cable 30 fixed to the coupling 39b to the machining head 2b is covered by, for example, a bellows-shaped sleeve 19 which is a protective member. The bellows-shaped sleeve 19 is configured to expand and contract in the direction of the inner wire 11's movement.

[0055] By equipping the displacement measuring device 1A with a bellows-shaped sleeve 19 and arranging this bellows-shaped sleeve 19 as described above to cover the inner wire 11, not only are the same effects as in the first embodiment achieved, but even when, for example, the inside of the housing 2a of the machine tool 2 is affected by the external measurement environment (for example, when the housing 2a has an external air communication characteristic (equipment such as a vent)), the exposed portion of the inner wire 11 from the outer cable 30 can be eliminated. As a result, it is possible to configure the encoder 40 so that the output of the signal corresponding to the displacement is not affected by dust or other debris.

[0056] [Third Embodiment] Figure 5 is a schematic diagram illustrating a displacement measuring device according to a third embodiment of the present invention. As shown in Figure 5, the displacement measuring device 1B according to the third embodiment is similar to the displacement measuring device 1A of the second embodiment in that it includes an encoder 40 and an outer cable 30. However, it differs from the second embodiment in that, on the machine tool 2 side, a constant maintenance section 18 is provided on the portion of the inner wire 11 that extends from one end of the outer cable 30 (the second end 37a side) fixed to the coupling 39b toward the machining head 2b, and has, for example, a debris-removing section 16 and an oiling section 17 for the inner wire 11.

[0057] The debris removal section 16 of the constant maintenance section 18 is equipped with, for example, a debris removal brush that intersects with the inner wire 11 and is aligned in the direction of the inner wire 11's movement, and constantly removes dust and other debris attached to the inner wire 11 as the inner wire 11 moves back and forth. In addition, the lubrication section 17 of the constant maintenance section 18 constantly applies a lubricating and protective material such as grease to the entire inner wire 11, which has been debris-free by the debris removal section 16. The applied lubricating and protective material may penetrate into the internal space 36 of the outer cable 30.

[0058] By equipping the displacement measuring device 1B with a continuous maintenance unit 18 and arranging this continuous maintenance unit 18 as described above, not only are the same effects as in the first embodiment achieved, but even when the inside of the housing 2a of the machine tool 2 is affected by the external measurement environment, etc. (for example, when the housing 2a has the external air communication characteristics described above), it becomes possible to remove dust and other debris adhering to the inner wire 11 and then lubricate it.

[0059] This effectively prevents the inner wire 11, which is wound back into the outer cable 30 on the machine tool 2 side, from carrying debris and causing various malfunctions with respect to the signal output corresponding to the displacement by the encoder 40. The regular maintenance unit 18 of the third embodiment may be configured to include, for example, at least one of a debris-proof unit 16 and an oiling unit 17.

[0060] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0061] For example, in the above embodiment, an example was described in which the outer cable 30 is placed between the machine tool 2 and the encoder 40, but the length of the outer cable 30 can be appropriately changed according to the location and circumstances in which the encoder 40 is used. In addition, the length of the inner wire 11 and the amount of movement (displacement) that can be measured by the inner wire 11 can be appropriately changed in accordance with the length of the outer cable 30. [Explanation of symbols]

[0062] 1,1A,1B Displacement measuring device 2 Machine tools 2a, 40a enclosure 2b Machining head 2c drive unit 3 Coupling base 3a Outlet bush 7 Fixing members 10 Displacement measuring device 11 Inner wire 11a First end 16. Debris-proof section 17 Lubricating part 18. Continuous Maintenance Department 19. Bellows-shaped sleeve 20 Control Units 30 Outer Cables 31 Hollow liner section 32 Spiral wire section 33 Mesh sleeve section 34 Outer tube section 35 Sheath section 37a Second end 37b Third end 38a, 38b Cup members 39a, 39b coupling 40 encoders 41 Wire Drum 42 Rotation axis 44 Rotation detection slit plate 46 Optical Sensors 47 Waveform shaping circuit

Claims

1. An encoder having a wire member with one end extended outwards from a pull-out section and the other end fixed to the moving body of a measuring object having a moving body, and outputting a signal corresponding to the displacement of the moving body based on the extension and retraction of the wire member from the pull-out section, The wire member has one end pulled out from one end, and the other end is positioned on the pull-out side of the encoder, and the outer cable has the wire member passing through it so as to move back and forth. Displacement measuring device.

2. The outer cable has elastic deformability and flexibility, as well as higher strength and toughness than the wire member, and comprises a liner portion extending from the center of the cable outward, through which the wire member is slidably passed, and a sheath portion covering the outside of the liner portion. Displacement measuring device according to claim 1.

3. The movable body is equipped with a coupling for securing one end of the outer cable to a fixed part. Displacement measuring device according to claim 1.

4. The outlet portion is provided with a coupling for securing the other end of the outer cable. Displacement measuring device according to claim 1.

5. The portion of the wire member extending from one end of the outer cable fixed to the coupling toward the moving body is further provided with at least one of the debris-proof portion and the lubrication portion of the wire member. Displacement measuring device according to claim 3.

6. The coupling is further provided with a protective member that covers the wire member from one end of the outer cable fixed to the coupling to the movable body. Displacement measuring device according to claim 3.

7. The outer cable is further provided with a protective member positioned on the outside of the outer cable and attached to the end of the outer cable to maintain the straightness of the outer cable. Displacement measuring device according to claim 1.

8. A moving object that moves in a straight line, A displacement measuring device comprising: an encoder having a wire member with one end extended outward from a pull-out section and the other end fixed to the movable body, and outputting a signal corresponding to the displacement of the movable body based on the extension and retraction of the wire member from the pull-out section; and an outer cable with one end extended outward from the one end of the wire member and the other end positioned on the pull-out section side of the encoder, through which the wire member passes freely. A device having a moving part.

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