JPH1163966A - Scale device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a detecting head to be easily taken out from and put in a scale by pressing the graduated surface of a scale so that the surface is always brought into contact with a reference sliding member which maintains the distance between a sensor provided on a slider unit side and the graduated surface at a fixed value. SOLUTION: A slider unit 10 is provided with a sensor 15 which detects magnetic graduations marked on a scale 4, slides relatively to the base unit 2, and makes a detecting head 14 to be taken out from and put in the scale 4 in the width direction. The distance between the sensor 15 and the graduated surface of the scale 4 marked with magnetic graduations is maintained at a fixed value by installing a reference sliding member 16 to the detecting head section 14 and the sliding member 16 is always brought into contact with the surface of the scale 4 marked with magnetic graduations by providing a pressing and sliding member 17. When the slider of the slider unit 10 slides against an enclosure 3, the detecting head section 14 moves along the scale 4 and the magnetic graduation of the scale 4 detected by means of the sensor 15 is outputted to a cable 13 as an electric signal, and then, the moved position of the head detecting section 14 is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scale device used for detecting a straight line position (relative position detection) in a machine tool, an industrial machine, or the like.

[0002]

2. Description of the Related Art Generally, a scale device of this type is provided with a base unit having a scale on which scales are recorded fixed to a base body, and slidably provided relative to the base unit. And a slider unit provided with a sensor for detecting the scale.

In this type of conventional scale device, a rod-shaped scale is used as a scale on the base unit side, while a detection head unit having a sensor for detecting a scale is provided on the slide unit side, and this detection head is provided. The scale has a structure in which the scale is slidably inserted and fitted. The detection head is provided with a free mechanism capable of changing the posture in order to allow a mounting tolerance or a component tolerance.

[0004]

In the case of such a conventional scale device, there is a drawback that the detection head portion can be inserted into and removed from the scale only from the end face side of the scale, and the assembling and maintenance are poor. Also,
The detection head section needs to be provided with a complicated free mechanism corresponding to a change in posture in order to allow a mounting tolerance and a component tolerance, which has caused an increase in cost. SUMMARY OF THE INVENTION It is an object of the present invention to solve such a problem and to provide a scale device in which a detection head portion can be inserted and removed in the width direction of the scale, and which can cope with a posture change without providing a complicated free mechanism. It is a thing.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a base unit having a scale on which a scale is recorded fixed to a base body, and a slidable relative to the base unit. A slider unit provided with a sensor for detecting a scale recorded on the scale, wherein the scale is formed in a thin plate shape, and the thin plate scale is floated at an intermediate portion. And a reference sliding member provided with a sensor on the slider unit side for maintaining a constant distance between the sensor and the scale recording surface of the scale; A pressure sliding member for applying pressure so that the scale recording surface of the scale is always in contact with the member; and a detection head for the scale. And it is obtained by the pluggable structure in the width direction of the scale.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. Here, a case of a magnetic linear scale device will be described as an example.

FIGS. 1 to 11 show a first embodiment of the present invention. In the drawing, reference numeral 1 denotes a scale device according to the present invention as a whole, and the scale device 1 includes a base unit 2.
And a slider unit 10 provided to be slidable relative to the base unit 2.

The base unit 2 has a long scale 4 on which magnetic scales are recorded and fixed inside a long case 3 as a base body, and a fixing hole 5 formed in the case 3.
Is fixed to one of the objects by bolting or the like.

On the other hand, the slider unit 10 has a scale 4
The slider 15 is provided with a sensor 15 for detecting a magnetic scale recorded on the slider 11, and is fixed to the other of the object to be measured by a bolt or the like in a fixing hole 12 formed in the slider 11.

When the slider unit 10 slides relative to the base unit 2 in the direction along the scale 4 (the direction of the arrow a) together with the linear movement of the measured object, the scale 4 detected by the sensor 15 is moved. Are output to the cable 13 as electric signals, and the movement position is detected (measured).

First, the structure of the base unit 2 in the scale device of the present embodiment configured as described above will be described in detail. The housing 3 as a base body in the base unit 2 is a long member having a substantially U-shaped cross section, and is fixed to the DUT in the fixing hole 5 with its U-shaped open surface facing downward. . The housing 3 is made of a metal material having a required rigidity, and may be formed by, for example, bending a sheet metal or extruding aluminum. Of course, it may be manufactured by machining.

A long scale 4 fixed inside the housing 3 is formed of a thin metal plate, and a scale (hereinafter referred to as a thin plate scale) 4 is provided on a surface facing the sensor in a longitudinal direction. A magnetic scale is recorded along. This magnetic scale has a magnetic north pole and a south magnetic pole, for example, NS, S
It may be an increment type in which recording is performed at predetermined intervals, such as -N, NS, or an absolute type in which absolute positions are recorded. The magnetic scale may be recorded in advance, or may be recorded after the thin plate scale 4 is fixed to the housing 3.

The thin plate-shaped scale 4 is fixed to the housing 3 at both left and right ends with the middle part floating.
That is, as shown in FIG. 2, brackets 6 are fixed to the left and right sides inside the housing 3, and both ends of the thin plate-shaped scale 4 are fixed to the bracket 6 by welding (indicated by X in FIG. 2). The part shown is the welded part). The thin plate scale 4 is fixed to the bracket 6 so that the recording surface of the magnetic scale is substantially perpendicular to the open surface of the housing 3 having a substantially U-shaped cross section.

The bracket 6 is made of a sheet metal having a required rigidity. As shown in FIG.
And the inner side of the rear plate 3c is fixed by welding while the end of the thin plate scale 4 is supported by the center support plate 6a of the bracket 6.

The thin plate scale 4 is welded to the bracket 6 with a predetermined tension applied. Resistance welding is used as a means for welding the thin plate scale 4, and the housing 3 is formed with an insertion hole 7 into which the electrode for resistance welding is inserted.

Next, the structure of the slider unit 10 will be described. The slider unit 10 includes a slider 11 provided below the housing 3 and a detection head unit 14 having a sensor 15 for detecting a magnetic scale recorded on the thin scale 4. The detection head unit 14 is connected with the support plate 11a. That is, the support plate 1 is placed on the slider 11 from the center of the upper surface.
1a is projected, and the detection head unit 14 is attached to the upper end of the support plate 11a.

The slider 11 is fixed to an object to be measured in a fixing hole 12.
From 1, a cable 13 from which an electric signal detected by the sensor 15 of the detection head unit 14 is output is led out.

A magnetoresistive element (MR sensor) is used as the sensor 15 of the detection head unit 14. The sensor 15 is fixed to the support plate 11a of the slider 11 by fixing means such as bonding, crimping by fitting, and pressing by a leaf spring. Fixed.

Further, the detection head unit 14 includes a sensor 15
A reference sliding member 16 for maintaining a constant distance between the reference scale 16 and the recording surface of the magnetic scale of the thin plate-shaped scale 4, and a recording surface of the magnetic scale of the thin plate-shaped scale 4 always in contact with the reference sliding member 16. And a pressure sliding member 17 for applying a pressure to the pressure member.

The reference sliding member 16 and the pressure sliding member 17
Are block-shaped members formed by using a lubricating resin material (for example, Duracon, Teflon, etc.) or a metal contained therein, and the reference sliding member 16 is fixed to the support plate 11a of the slider 11 by fixing screws 18. The pressure sliding member 17 is supported by a leaf spring 20 fixed to the reference sliding member 16 by a fixing screw 19 so as to be pressed against the reference sliding member 16.

The thin plate scale 4 is sandwiched between the reference sliding member 16 and the pressure sliding member 17, and the thin plate scale 4 is always connected to the reference sliding member 16 by the pressure sliding member 17. By being pressed, the distance between the sensor 15 and the recording surface of the magnetic scale of the thin plate scale 4 is always kept constant.

When the slider 11 is slid relative to the housing 3, the detection head 14 moves along the thin plate scale 4, and the magnetic scale of the thin plate scale 4 detected by the sensor 15 at that time is set. The movement position is detected by being output to the cable 13 as an electric signal.

In the above configuration, the distance between the detection surface of the sensor 15 and the recording surface of the magnetic scale of the thin plate scale 4, that is, the clearance b, is 0.5 mm for a reproduction wavelength of 0.5 mm when a magnetoresistive element is used for the sensor 15. The usable clearance range is, for example, 0.35 ± 0.25 mm. Therefore, when the clearance is set at the center of the use range and the reference sliding member 16 is installed with the detection surface of the sensor 15 as a reference,
The reference sliding member 16 may have a thickness of 0.35 mm.

The reference sliding member 16 may have a structure in which the detection surface of the sensor 15 is opened as shown in FIG. 7A, or may completely cover the detection surface of the sensor 15 as shown in FIG. It may have a structure.

In the scale device 1 of the present embodiment configured as described above, the detection head unit 14 is
It can be inserted and removed in the width direction of the thin plate scale 4. That is, in this scale device 1, the thin plate-shaped scale 4 is arranged so that the recording surface of the magnetic scale is substantially perpendicular to the open surface of the housing 3, and as shown in FIG.
By forming the opening dimension d of the open surface of the housing 3 larger than the thickness dimension c of the housing 4, the detection head unit 14 can be inserted and removed from the open surface of the housing 3 in the width direction of the thin scale 4.

As described above, since the detection head 14 is structured to be removable in the width direction of the thin scale 4, the detection head 14 can be moved from any position in the position detection direction of the thin scale 4, that is, in the length direction. Since it can be assembled and detached, the assembling property and the maintenance property are good.

It is to be noted that the detection head unit 14 is formed by
After assembling, as shown in FIG. 5, rubber dust lip strips 21a and 21b for closing the open surface of the housing 3 are attached, thereby preventing dust, oil, and other foreign substances from entering the housing 3, and The protection unit 14 can be protected and the detection head unit 14 can be prevented from falling off the housing 3.
When the detection head unit 14 is removed for maintenance or the like, the dust lips 21a and 21b may be removed.

Normally, in this type of scale device, when the housing 3 or the slider 11 is mounted on the object to be measured, a mounting error always occurs. The larger the allowable amount of the error, the easier the mounting. In the example scale device 1, a sufficient allowance can be secured.

First, as shown in FIG. 8, the magnetic scale 4a of the thin scale 4 is recorded on a long track in the width direction of the thin scale 4, and the track length e of the magnetic scale 4a is determined by a sensor 15 Is larger than the length f in the track direction, the difference becomes the allowable amount of the mounting error in the track direction g (the direction orthogonal to the position detection direction). The detection head 14 includes a reference sliding member 16 and a pressure sliding member 17.
Since the thin plate-shaped scale 4 is sandwiched between the first and second positions, the position can be freely shifted in the track direction.

Here, for example, the width h of the thin plate scale 4 is 9
mm, the track length e of the magnetic scale 4a is 7 mm, and the track direction length f of the sensor 15 is 3 mm, the allowable range is ± 2 mm, and the allowable range is very wide.

Further, as shown in FIG. 9, the inclination at an angle theta ₁ slider 11 is inclined, if the sensor 15 to the magnetic scale has not undergone an azimuth deviation, inclination tolerance of the sensor 15 is ±
Since about 1 °, for example, θ _{1 is set} to 1 ° and the slider 11
If the width i in the position detection direction is 50 mm, the amount of inclination j is 0.8 mm, which is a sufficient allowance. The detection head unit 14 includes a reference sliding member 16 and a pressure sliding member 17.
Since the thin plate-shaped scale 4 is sandwiched between the first and second positions, the position can be freely shifted in the azimuth direction.

When the attitude of the slider 11 changes at an inclination θ ₂ as shown in FIG. 10, the thin plate scale 4 sandwiched between the reference sliding member 16 and the pressing sliding member 17 of the detection head unit 14 is used. Is twisted as shown, so that the recording surface of the magnetic scale always follows the reference sliding member 16 while being pressed.

Further, with respect to a change in the posture at the inclination θ ₃ as shown in FIG.
As shown in the figure, the thin plate-shaped scale 4 sandwiched between the pressure sliding member 6 and the pressure sliding member 17 bends as shown, so that the recording surface of the magnetic scale always follows the reference sliding member 16 while being pressed.

As described above, in the scale device 1 of the present embodiment, any posture change can be tolerated with a simple configuration without providing a complicated free mechanism for responding to the posture change.
In addition, the allowable amount can be increased.

FIGS. 12 and 13 show a second embodiment of the present invention. Here, portions corresponding to those of the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

The difference between the second embodiment and the first embodiment is the structure of the detection head unit 14, that is, the detection head unit 14 in the scale device 1 of the second embodiment.
In this embodiment, a sliding member 22 having a concave groove 23 through which the thin scale 4 passes is provided in place of the reference sliding member 16 and the pressure sliding member 17 of the first embodiment.

The sliding member 22 is a block-like member formed of a lubricating resin material or a metal containing material similar to the reference sliding member 16 and the pressure sliding member 17 in the first embodiment. There is a concave groove 23 formed at the center thereof,
This is to keep the distance between the sensor 15 and the recording surface of the magnetic scale of the thin plate scale 4, that is, the clearance, within a range where the magnetic scale can be detected by the sensor 15.

That is, in the structure of this embodiment, the sensor 15 is
3, the groove width k of the concave groove 23 of the sliding member 22 in this configuration is equal to the thickness m of the thin plate-shaped scale 4.
The size is set to be larger than the total thickness of the thickness m of the thin plate scale 4 and the maximum clearance capable of detecting the magnetic scale by the sensor 15.

For example, when a magnetoresistive element is used as the sensor 15, the maximum clearance at which the magnetic scale can be detected at a reproduction wavelength of 0.5 mm is 0.6 mm, and the thin scale 4
When the thickness m of the groove is 0.15 mm, the groove width k of the concave groove 23 is set to 0.15 <k ≦ 0.75 mm. Is maintained within a range in which the position can be detected, so that a normal position detection signal can be obtained. The sensor 15 may be provided with a protection means as needed.

In the second embodiment, the first
Similarly to the embodiment, the detection head portion 14 can be inserted and removed in the width direction of the thin plate scale 4. In addition, the same effect as in the first embodiment can be obtained regarding the tolerance of the mounting error.

In the second embodiment, the sliding member 22 of the detecting head section 14 is composed of two parts, a main sliding member 22a and a sub sliding member 22b, as shown in FIG. It may be integrated by screws 24.

Further, the sliding member 22 of the detection head unit 14
May have a structure as shown in FIG. That is, in the sliding member 22 in the example of FIG. 15, the auxiliary sliding member 22b is supported by the leaf spring 20 with respect to the main sliding member 22a.
Projections 23a, 23b which contact the main sliding member 22a above and below the sensor 15 are attached to the sub-sliding member 22b.
Are formed between the upper and lower protruding portions 23a and 23b.

Here, the sliding member 22 is connected to the detecting head 1.
4 rigid Thinning to miniaturization becomes small, it can be kept in a predetermined range clearance groove width k is opened when the slider 11 has caused the change in the attitude of the inclination theta ₂ as shown in FIG. 10 described above Since it may disappear, it is recommended to reinforce it by adopting a structure as shown in FIG. 16, for example.

That is, in the detection head section 14 shown in FIG. 16, a sub-sliding member 22b cantilevered by a screw at the base end of a metal mounting board 22A provided at the tip of a support plate 11a of the slider 11. However, since rigidity cannot be secured when the thickness is reduced, the metal reinforcement plate 22B is reinforced by screwing the base end together with the metal. As shown in FIG. 17, a front view of the mounting board 22A with the sub-sliding member 22b removed is provided with a main sliding member 22a having a U-shaped planar shape and the sensor 15 attached thereto. It is screwed around.

In the detection head section 14 shown in FIG. 16, the groove width k of the concave groove 23 in the sliding member 22 is set by the dimensions of the main sliding member 22a and the mounting board 22A forming the Y dimension. , Sub-sliding member 22b and metal reinforcing plate 2
2B is a groove 2 having a desired groove width k by being screwed.
3 is set. If the desired groove width k cannot be obtained only by the dimensions of each component, the groove width k can be adjusted by the spacer 25 interposed between the base end of the mounting board 22A and the sub-sliding member 22b.

The detection head unit 1 shown in FIG.
4, a sliding member 2 from which the thin scale 4 is inserted and removed.
The thin plate-shaped scale 4 is formed in the concave groove 23 by chamfering the distal end portions 22a ₁ and 22b ₁ of the main sliding member 22a and the sub sliding member 22b forming the second concave groove 23. It can be easily inserted. The thin scale 4 can be easily inserted into the groove 23 by chamfering at least one of the distal ends 22a ₁ and 22b ₁ of the main sliding member 22a and the sub sliding member 22b. Can be.

In this structure, a wiper for removing dust or the like may be provided in the left-right direction of the sensor 15 as necessary.

That is, as shown in FIGS. 18 and 19, wipers 27 are attached to both ends of the sliding member 22 with the wiper holder 26 formed of an elastic metal plate or the like, as shown in FIGS. it can. in this case,
The wiper 27 is provided so as to sandwich the thin plate-shaped scale 4 from both sides.

The wiper 27 is made of felt, sponge, or the like, and has improved lubricity by being impregnated with oil. As the material of the wiper 27, rubber may be used. The wiper 27 can be easily replaced by elastically deforming the wiper holder 26.

In the detection head section 14 to which the wiper 27 is attached as described above, dust and the like adhering to the front and back surfaces of the thin plate-shaped scale 4 passed through the concave groove 23 can be removed by the wiper 27.

Here, as shown in FIG. 20, by forming the side edge of the wiper 27 so as to be inclined with respect to the longitudinal direction of the thin plate scale 4, the wiper 27 slides from the surface of the thin plate scale 4 by sliding. The removed dust and the like can be guided out of the surface of the thin plate-shaped scale 4 and eliminated.

In this case, the inclination of the wiper 27 should be such that dust or the like goes to the open side of the housing 3. That is, in this example, dust and the like are on the open surface side (lower surface side) of the housing 3.
The wiper 27 has an inverted trapezoidal slope so that dust and the like are effectively discharged from the open surface of the housing 3 to the outside of the housing 3. The wiper 27 can of course be used in other embodiments.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, in the above embodiment, the housing 3 having a substantially U-shaped cross section is used as the base body. However, instead of the housing 3, an open type scale in which the base body is formed by a flat plate or a bent plate having an L-shaped cross section. Needless to say, the present invention can be applied to an apparatus.

Further, in the above embodiments, examples in which the present invention is applied to a magnetic scale device have been described. However, the present invention is also applied to an optical scale device and a capacitance type scale device in addition to the magnetic scale device. Can be done in any manner.

[0055]

As described above, the scale device of the present invention has a structure in which the detection head can be inserted and removed in the width direction of the thin scale, so that the detection head can be assembled from any part of the thin scale. Can be detached, so that the assembling property and the maintenance property are very good. Further, in the scale device of the present invention, since there is no need to provide a complicated free mechanism for responding to the change in the attitude of the slider, the number of components can be reduced and a low-cost scale device can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a first embodiment of a scale device according to the present invention.

FIG. 2 is a front view partially cut away.

FIG. 3 is a side view of the same.

FIG. 4 is a vertical sectional side view of a main part of the housing unit.

FIG. 5 is an explanatory view showing a state in which a dust lip is attached to the housing.

FIG. 6 is a top view of the detection head unit.

FIG. 7 is a transverse sectional view showing an example of the structure of the reference sliding member.

FIG. 8 is an explanatory diagram of the tolerance of the mounting error.

FIG. 9 is an explanatory diagram of the tolerance of the mounting error.

FIG. 10 is an explanatory diagram showing the tolerance of an attachment error.

FIG. 11 is an explanatory diagram of an allowable mounting error.

FIG. 12 is a partially cutaway perspective view showing a second embodiment of the scale device according to the present invention.

FIG. 13 is a side view of the same.

FIG. 14 is a side view of a modification of the second embodiment.

FIG. 15 is a side view of another modification of the second embodiment.

FIG. 16 is a side view of an example in which the detection head is reinforced.

FIG. 17 is a front view of the same state with the sub-sliding member removed.

FIG. 18 is a side view of an example in which a wiper is provided in the detection head unit.

FIG. 19 is a front view showing a state where a sub sliding member is removed.

FIG. 20 is an example of a shape in which a side edge of a wiper is inclined.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scale device, 2 ... Base unit, 3 ... Housing (base body), 4 ... Thin plate scale, 10 ... Slider unit, 11 ... Slider, 14 ... Detection head part, 15 ... Sensor, 16 ... Reference sliding member, 17 ... Pressure sliding member, 22 ...
Sliding member, 23 ... concave groove

Claims (2)

[Claims] 1. A base unit having a scale on which scales are recorded fixed to a base body, and a sensor slidably provided relative to the base unit and detecting a scale recorded on the scale. And a slider unit comprising: a scale unit formed of a thin plate; and fixing the thin plate scale to the base body at both ends with an intermediate portion floating, On the unit side, the sensor is provided, and a reference sliding member for keeping the distance between the sensor and the scale recording surface of the scale constant, and the scale recording surface of the scale is provided on the reference sliding member. A pressure sliding member for applying pressure so as to be always in contact therewith, and a detection head portion comprising: Scale apparatus being characterized in that the pluggable structure in the width direction of the scale. 2. A base unit having a scale on which scales are recorded fixed to a base body, and a sensor slidably provided relative to the base unit and detecting a scale recorded on the scale. And a slider unit comprising: a scale unit formed of a thin plate; and fixing the thin plate scale to the housing at both ends with an intermediate portion floating. A detection member provided with the sensor on the side thereof, and a sliding member having a concave groove for keeping a distance between the sensor and the scale recording surface of the scale within a range where the scale can be detected by the sensor. A head portion is provided, and the detection head portion is configured to be removable from and inserted into the scale in a width direction of the scale. Kale apparatus.