JPH08273314A - Linear reciprocating body - Google Patents

Abstract

PURPOSE: To enhance the positional accuracy of a linear reciprocating body at the time of movement. CONSTITUTION: A linear reciprocating device has two guide shafts 21, 22 disposed in parallel, a carriage 24 linearly reciprocatably supported to the guide shafts 21, 22 and a position detecting system constituted of a main scale made of a steel band with a long strip-form slit 36 and a photo interrupter 34. In the linear reciprocating device, the upper side part of the main scale 35 in the direction of the length of the slit 36, namely, the width of a part protruded from the part between the light emitting part and the light receiving part of the photo interrupter 34 is widened. Therefore, the rigidity of the main scale 35 is enhanced to increase the accuracy of measuring the position of the carriage 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
Alternatively, the present invention relates to a linear reciprocating device that linearly reciprocates an optical head or the like used in an information recording / reproducing device that reproduces information from a recording medium.

[0002]

2. Description of the Related Art Conventionally, an information recording / reproducing apparatus has a magnetic system and an optical system, and in recent years, the optical system has been attracting attention. As an apparatus for recording / reproducing information using a light beam, there are a CD using a disk-shaped recording medium, a laser disk, and an optical card that reciprocates a card-shaped recording medium. is there. These linear reciprocating devices are properly used according to the purpose, but in each case, tracks are formed on the recording medium at intervals of several μm, and spots of several μm are formed between the tracks by a light beam. , Information recording / playback is performed.

For example, in the case of an optical card, a mounting table on which an optical card as a recording medium is mounted and an optical head on which an optical pickup for recording / reproducing information is mounted are driven in directions orthogonal to each other and are parallel to a track. Recording / reproducing is performed by irradiating a light beam on the optical card while following the.

The card mounting table and the optical head in such an information recording / reproducing apparatus are both linear reciprocating bodies (hereinafter referred to as carriages), and two guides are provided on the base 1 of the apparatus body as shown in FIG. The shafts 2 and 3 are fixed in parallel, and the carriage 4 is supported by the guide shafts 2 and 3 so as to be linearly movable in the X direction.

A coil 6 of a linear motor 5 for generating thrust in the X direction is attached to the side surface of the carriage 4 on the side of the guide shaft 2, and a light shielding plate 7 is attached to the side surface on the opposite side. The photo interrupters 8 and 9 are provided at both ends of the moving range of the carriage 4. Further, a photo interrupter 10 is attached to the attachment side of the light shielding plate 7 of the carriage 4, and the main scale 11 made of a steel strip having fine strip-shaped slits 11a.
Is supported on the base 1 in a direction parallel to the guide shaft 3 without being bent, and is interposed between the light receiving portion and the light emitting portion of the photo interrupter 10.

A vernier scale made of a thin steel plate (not shown) having a slit having the same shape as the slit 11a is attached to the light receiving portion of the photo interrupter 10 to form a linear encoder for position detection.

When recording / reproducing information, when the linear motor 5 is driven to move the carriage 4, the light shielding plate 7 is detected by the photo interrupters 8 and 9 and reciprocates between them. At that time, the light receiving unit of the photo interrupter 10 controls the driving of the linear motor 5 by a pulse signal obtained by a change in the amount of transmitted light passing between the main scale 11 and the sub scale.

As described above, in the linear encoder, in addition to the transmissive type using the steel strip provided with the slit, the transmissive type using the glass plate on which the metal is vapor-deposited in the strip-shaped pattern and the strip-shaped groove are formed. There is a reflection type using a resin band. However, in the case of a glass plate, there is a risk of cracking or chipping due to dropping, impact, etc., which is not preferable in terms of device reliability.

Also, in the case of a resin band, there is little concern about cracking or chipping, but elongation is likely to occur, and the positional accuracy of the linear encoder is a strip pattern width such as a slit formed on the main scale 11. Since the positional accuracy of the carriage in the linear reciprocating moving device used in an optical information recording device or the like is on the order of several μm, when extension occurs, the pattern width changes due to this extension. The desired positional accuracy cannot be satisfied. In that respect, steel strips are often used because they have a relatively small elongation and there is no fear of cracking or chipping.

[0010]

However, the photo interrupter 10, which is an element constituting the linear encoder, is downsized and can be constructed without taking up space, and as a result, the light emitting portion through which the main scale 11 passes. And the length of the opposing surface of the light receiving part is short. Therefore, there is a problem that the width of the main scale 11 becomes narrow, and the steel strip, which has a small elongation, becomes weak in rigidity, resulting in a decrease in position detection accuracy.

Further, the carriage 4 may generate rotation mode vibration even when it is moving at a constant speed, but during acceleration / deceleration, a rotational movement in the A direction is generated due to the moment of inertia. Since the linear encoder is arranged at a position far from the point of application of the driving force, the rotational motion component is large and is detected as a large velocity fluctuation component. For example, if the carriage 4 rotates in the + direction due to some influence, there is no fluctuation in the X direction in reality, but the linear encoder performs speed control assuming that there is speed fluctuation in the + direction of X, and the carriage 4 is further controlled by the moment of inertia. There is a problem that the rotational movement is promoted in the opposite direction.

The object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a linear reciprocating device that improves the positional accuracy when the linear reciprocating body moves.

[0013]

A linear reciprocating device according to a first aspect of the present invention for achieving the above object is to provide two guide shafts arranged in parallel with each other and to reciprocate linearly with respect to the guide shafts. In a linear reciprocating body having a supported carriage, a drive actuator for linearly reciprocating the carriage, and a position detection system composed of a steel strip having a strip-shaped slit and a photo interrupter, the steel strip is provided with respect to the slit. One of the frame portions on both sides is characterized in that one frame portion has a larger sectional shape to improve rigidity.

A linear reciprocating device according to a second aspect of the present invention includes two guide shafts arranged in parallel, a carriage supported so as to be linearly reciprocable with respect to the guide shafts, and a linear reciprocating motion of the carriage. In a linear reciprocating body having a drive actuator and a position detection system composed of a steel strip having a strip-shaped slit and a photo interrupter, one of the two side frame portions of the steel strip with respect to the slit is reinforced for reinforcement. It is characterized by stacking steel frames of.

A linear reciprocating device according to a third aspect of the present invention includes two guide shafts arranged in parallel, a carriage supported so as to be linearly reciprocable with respect to the guide shafts, and a linear reciprocating motion of the carriage. In a linear reciprocating body having a drive actuator and a position detection system composed of a steel strip having a strip slit and a photo interrupter, the carriage drive actuator is arranged on one side of the carriage, and the carriage drive actuator is The position detection system is arranged in the vicinity of the support point of the carriage on the side of the point of action.

A linear reciprocating device according to a fourth aspect of the present invention comprises two guide shafts arranged in parallel, a carriage supported so as to be linearly reciprocable with respect to the guide shafts, and a linear reciprocating motion of the carriage. In a linear reciprocating movable body having a drive actuator and a position detection system composed of a steel strip having a strip slit and a photo interrupter, the carriage drive actuators are arranged on both sides of the carriage, and near the center of gravity of the carriage. The position detection system is arranged.

[0017]

In the linear reciprocating device according to the first invention and the second invention having the above-mentioned structure, the rigidity of the steel strip in the position detection system for driving and controlling the linear reciprocating body is improved and its elongation is prevented. To do.

In the linear reciprocating device according to the third aspect of the present invention, when the carriage is driven by the actuator, even if a rotational speed component is generated, the position detection system is not significantly affected.

In the linear reciprocating device according to the fourth aspect of the present invention, when the carriage is driven by the actuators, the actuators on both sides of the linear drive device rarely generate a rotational speed component, and even if it occurs, the position detection system is not affected. There is no effect.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a block diagram of a linear reciprocating moving device which is a first embodiment of an information recording / reproducing device. The linear moving body in this device comprises a card or a carriage of an optical head. On the base 20 of the device body,
A pair of parallel guide shafts 21 and 22 are supported and fixed by a plurality of mounting members 23, respectively. The carriage 24 has a substantially rectangular box shape, a slide bearing 25 is provided on one side of the carriage 24, and a slide member 26 having a U-shaped cross section is provided on the other side surface of the carriage 24. The guide shaft 22 is fitted and inserted, and the guide shaft 22 is sandwiched by the slide member 26 so as to be slidably supported along the guide shafts 21 and 22, and the slide member 26 regulates the vertical rotation. There is.

A coil 27 is attached to the side surface of the carriage 24 on the side of the slide bearing 25.
The yoke 29 is composed of a rectangular frame body that is long in a direction parallel to the guide shaft 22 mounted on the base 20, and a magnet 29 is fixed to one frame portion in the longitudinal direction of the yoke 29. Inserted, Carriage 2
A linear motor 30 serving as an actuator of No. 4 is configured.

A light-shielding plate 31 protruding laterally is mounted on the sliding member 26, and photo interrupters 32, 33 for detecting the light-shielding plate 31 are provided on the base 21 near both ends of the guide shaft 22. It is installed. Further, a photo interrupter 34 is attached above the light shielding plate 31, and a main scale 35 made of a steel strip having a narrow strip-shaped slit 36 between the light emitting portion and the light receiving portion thereof.
Is passing. The main scale 35 has one end attached to a support member 37 on the base 20, and the other end bent along the peripheral surface of a columnar member 38 provided on the base 20 and then on the base 20 by a coil spring 39. It is attached to the fixing member 40, and is arranged in parallel to the guide shafts 21 and 22 and in a non-deflected state. As shown in FIG. 2, in the main scale 35, in order to improve the rigidity, the upper portion 35a protruding from between the light receiving portion and the light emitting portion of the photo interrupter 34 becomes wider than the lower portion 35b of the slit 36. There is.

Further, a sub scale 41 made of a thin steel plate having a slit of the same shape and size as the slit 36 is attached to the light receiving portion of the photo interrupter 34. The sub scale 41 and the main scale 35 are attached. A linear encoder is constructed by using this.

The linear reciprocating device is a linear motor 30.
When a current is applied to the coil 27, a thrust force is generated in the X direction, and the carriage 24 slides along the guide shafts 21 and 22. Then, the light shielding plate 31 of the carriage 24 reaches the position of the photo interrupter 32 or 33, and when it is detected between the light emitting portion and the light receiving portion, it reversely slides to reciprocate. At this time, when the positional relationship between the main scale 35 and the subscale 41 changes, the amount of transmitted light of the photo interrupter 34 changes and a pulse signal is obtained by the linear encoder. The position signal and the speed signal are obtained from this pulse signal, and the linear motor Thirty
Is controlled to improve the positional accuracy of the carriage 24.

In the linear reciprocating device constructed as described above, the tensile strength of the main scale 35 is improved and the detection accuracy is prevented from lowering due to the extension of the main scale 35.
The accuracy of the moving speed can be increased.

FIG. 3 and FIG. 4 are main part configuration diagrams of the second embodiment, in which the upper portion 3 protruding from between the light receiving portion and the light emitting portion of the photo interrupter 34 in the main scale 35 of the first embodiment.
Steel strips 50, 50 are laminated on both surfaces of 5a in a laminated manner.

In the linear reciprocating device constructed as described above, the tensile strength of the main scale 35 is improved as in the first embodiment, and the detection accuracy is prevented from deteriorating due to the extension of the main scale 35. The accuracy of the moving speed of 24 can be improved.

FIG. 5 and FIG. 6 are main part configuration diagrams of the third embodiment. The main scale 35 in the first embodiment is an upper portion 35a protruding from between the light receiving portion and the light emitting portion of the photo interrupter 34. Frames 60 made of steel plates are attached to both surfaces, and the main scale 35 has support members 6 on the base 20 at both ends.
It is fixed by 1, 61.

In the linear reciprocating device thus constructed, the tensile strength of the main scale 35 is further improved, and the main scale 35 is improved.
Since the detection accuracy is prevented from lowering due to the extension of the carriage, the accuracy of the moving speed of the carriage 24 can be further improved.

FIG. 7 is a block diagram of the fourth embodiment.
Main scale 3 mounted on the base 20 in the embodiment of
5 is arranged on the guide shaft 21, and the photo interrupter 34 is arranged on the main scale 3 of the carriage 24.
It is attached to the position corresponding to 5.

Since the linear encoder for position detection is arranged above the supporting point where the driving force acts in the linear reciprocating device thus constructed, an inertia moment is generated when the carriage 24 is accelerated or decelerated. However, no rotational movement occurs and erroneous control does not occur.

FIG. 8 is a block diagram of the fifth embodiment.
A plurality of bearings 70 in which the carriage 24 in the above embodiment is provided obliquely in place of the slide bearing 25 and the sliding member 26.
The carriage 71 is configured to sandwich the guide shafts 21 and 22, and linear motors 72 and 72 are symmetrically provided on both sides of the carriage 71.

A photo interrupter 34 is mounted above the center of gravity of the carriage 71, and a main scale 35, which is arranged parallel to the guide shafts 21 and 22, is provided between the light emitting portion and the light receiving portion of the photo interrupter 34. Passing through.

In the linear reciprocating device thus constructed, the carriage 71 has two linear motors 7 from both sides.
Since the linear encoder is driven by Nos. 2 and 72 and the linear encoder is located at the position of the center of gravity of the carriage 71, no rotational moment acts on the carriage 71 during acceleration / deceleration, which prevents erroneous control of the apparatus. Further, the carriage 71 uses the bearing 70 to guide the guide shaft 2
Since it is supported on Nos. 1 and 22, the movement is smooth and no vibration in the rotation mode is generated.

[0035]

As described above, the linear reciprocating apparatus according to the first and second aspects of the present invention improves the rigidity of the main scale of the position detecting system for controlling the drive of the linear reciprocating movement. Positional accuracy due to stretching can be improved.

In the linear reciprocating device according to the third aspect of the present invention, when the carriage is driven by the actuator, even if a rotational speed component is generated, the influence on the position detection system is small, so that erroneous control can be prevented.

In the linear reciprocating device according to the fourth aspect of the invention, when the carriage is driven by the actuators, the actuators on both sides of the carriage rarely generate the rotational speed component, and even if it occurs, the linear velocity reciprocating device does not affect the position detection system. Since there is no influence, erroneous control can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment.

FIG. 2 is a sectional view of a main part thereof.

FIG. 3 is a perspective view of a main part of the second embodiment.

FIG. 4 is a sectional view thereof.

FIG. 5 is a perspective view of an essential part of a third embodiment.

FIG. 6 is a sectional view thereof.

FIG. 7 is a perspective view of a fourth embodiment.

FIG. 8 is a perspective view of a fifth embodiment.

FIG. 9 is a perspective view of a conventional example.

[Explanation of symbols]

 24, 71 Carriage 21, 22 Guide shaft 30, 72 Linear motor 31 Light-shielding plate 32, 33, 34 Photointerrupter 35 Main scale 36 Slit 50 Steel band 60 Frame body 70 Bearing

Claims (6)

[Claims] 1. A two parallel guide shafts, a carriage supported so as to be linearly reciprocable with respect to the guide shafts, a drive actuator for linearly reciprocating the carriage, and strip slits. In a linear reciprocating body having a steel strip and a position detection system composed of a photo interrupter, the rigidity is improved by enlarging the cross-sectional shape of one of the frame portions on both sides of the slit of the steel strip. A linear reciprocating moving body characterized in that. 2. The linear reciprocating body according to claim 1, wherein one of the frame portions on both sides of the slit of the steel strip has a wider width. 3. Two guide shafts arranged in parallel, a carriage supported so as to be capable of linearly reciprocating with respect to the guide shafts, a drive actuator for linearly reciprocating the carriage, and strip slits. In a linear reciprocating body having a steel strip and a position detection system composed of a photo interrupter, a steel frame for reinforcement is laminated on one of the frame portions on both sides of the slit of the steel strip. A straight reciprocating moving body. 4. The reinforcing steel frame is formed of a steel plate,
The linear reciprocating body according to claim 3, wherein the linear reciprocating body is inserted into a positioning groove provided on the main body base, and the frame body is abutted against a side surface of the groove portion so as to be attached without applying tension. 5. A pair of guide shafts arranged in parallel, a carriage supported so as to be linearly reciprocable with respect to the guide shafts, a drive actuator for linearly reciprocating the carriage, and strip slits. In a linear reciprocating body having a position detection system composed of a steel strip and a photo interrupter, the carriage driving actuator is arranged on one side of the carriage, and the carriage is supported on the side of the action point of the carriage driving actuator. A linear reciprocating moving body, wherein the position detection system is arranged near a point. 6. A pair of guide shafts arranged in parallel, a carriage supported so as to be linearly reciprocable with respect to the guide shafts, a drive actuator for linearly reciprocating the carriage, and a strip slit. In a linear reciprocating body having a position detection system composed of a steel strip and a photo interrupter, the carriage driving actuators are arranged on both sides of the carriage, and the position detection system is arranged near the center of gravity of the carriage. Characteristic linear reciprocating moving body.