JPH0783228A - Small thin rolling guide unit and drive unit - Google Patents

Abstract

(57) [Abstract] [Purpose] A small-sized thin-walled rolling guide unit that contributes to downsizing and cost reduction of devices to be incorporated, such as industrial robots, and has high reliability in relative positioning of the relative moving members. And a drive unit comprising drive means added to the unit. [Structure] A detected portion forming a relative position detecting means for detecting a relative position between the first and second relative movement members 1 and 2 is formed into a thin film and provided on the relative movement member to obtain the above-mentioned effect. It has gained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized thin-walled rolling guide unit and a drive unit including drive means for driving the unit.

[0002]

2. Description of the Related Art FIG. 10 shows a conventional small-sized thin-walled rolling guide unit. Incidentally, this rolling guide unit is disclosed in Japanese Utility Model Publication No. 64-6407.

As shown in the figure, the rolling guide unit has a bed 101 as a first relative moving member and a table 102 as a second relative moving member provided outside the bed 101. . Each of the bed 101 and the table 102 is formed thin and has a substantially U-shaped cross section perpendicular to the relative movement direction.
Track grooves 101a and 102a are formed in the outer portion of the bed 101 and the inner portion of the table 102 so as to correspond to each other along the relative movement direction.

A rectangular plate-shaped cage 103 is interposed between the track grooves 101a and 102a. The holder 103 has a plurality of openings 103a arranged in parallel,
A ball 104 as a rolling element in each of the openings 103a.
Is rotatably inserted. These balls 104
Roll on the track grooves 101a and 102a as the bed 101 and the table 102 move relative to each other.

[0005]

The rolling guide unit having the above-mentioned structure is used, for example, in a mechanical portion which is to perform relative motion in an industrial robot or the like, but requires extremely high operating accuracy as in the industrial robot. In the case of the device, it is necessary to detect the relative position of the bed 101 and the table 102 with high accuracy. Therefore, as a relative position detecting means, a long linear scale 11 as shown in FIG. 10 is used.
0 and the sensor 111 are installed side by side. The linear scale 110 is, for example, finely magnetized in the longitudinal direction in multiple poles, and is fixed to the table 102 when the table 102 is used as the movable side of the rolling guide unit. The sensor 111 is a magnetic sensor and is provided on the fixed side together with the bed 101.

As is apparent from the above, in the conventional small-sized thin-walled rolling guide unit, the relative position detecting means provided for detecting the relative position of the bed 101 and the table 102 occupies a large space for the components constituting the relative position detecting means. Further, it is a relatively expensive problem, which is a problem to be solved in order to reduce the size and cost of an industrial robot or the like in which a rolling guide unit is incorporated.

Since the bed 101 is mounted on a predetermined base (not shown) of an industrial robot or the like, and the sensor 111 is also mounted on the base via a bracket or the like, the linear scale 11
Mechanically, between 0 and the sensor 111, in addition to the respective constituent members of the rolling guide unit, a large number of members such as these bases and brackets intervene. Therefore, no matter how high the detection accuracy of the relative position detecting means is set, it is not always possible to increase the reliability of relative positioning of the bed 101 and the table 102 by cumulatively affecting the assembly error between these members. It wasn't easy.

In the rolling guide unit described above, various driving means for relatively driving the bed 101 and the table 102 are added, and the rolling guide unit and the driving means are combined to form a driving unit. Often used.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and contributes to downsizing and cost reduction of a device to be incorporated such as an industrial robot, and moreover, the relative moving members provided therein. An object of the present invention is to provide a small-sized thin-walled rolling guide unit with high reliability in relative positioning, and a drive unit obtained by adding drive means to the unit.

[0010]

According to the present invention, there is provided a first relative movement member having an orbit along its relative movement direction on an outer side portion,
A second relative movement member having a U-shaped cross section perpendicular to the relative movement direction, the second relative movement member being provided outside the first relative movement member and having a track corresponding to the track in an inner portion; In a small-sized thin-walled rolling guide unit including a rolling element interposed between raceways, a detected portion is provided along one of the relative moving members along the raceway, and one of the relative movement members is provided with the detected portion on the other side. The detection means for detecting the detection unit is provided. Further, according to the present invention, the first relative moving member having a track along the relative moving direction on the outer side and the cross-sectional shape perpendicular to the relative moving direction are substantially U.
A second relative moving member having a character shape and provided on the outside of the first relative moving member and having a track corresponding to the track on the inner side; a rolling element interposed between the tracks; In a drive unit including a drive unit that relatively drives the first and second relative movement members, a detected portion is provided along one of the relative movement members along the track, and On the other hand, a detecting means for detecting the detected portion is provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a small-sized thin-walled rolling guide unit and a drive unit obtained by adding drive means thereto will be described as embodiments of the present invention with reference to the accompanying drawings. The drive means included in this drive unit is a linear DC motor, which is of the movable magnet type.

First, the structure of the small-sized thin-walled rolling guide unit according to the present invention will be described below.

As shown in FIG. 1, the rolling guide unit according to the present invention has a bed 1 and a table 2 as a first relative moving member and a second relative moving member, respectively. The bed 1 and the table 2 are obtained, for example, by bending and punching a steel plate or the like as a raw material, and each is formed in a longitudinal shape and has a cross-sectional shape perpendicular to the longitudinal direction, that is, the relative transfer direction. Stands for U
It is formed to have a letter shape. As is especially clear from FIG. 2, the left and right outer portions of the bed 1 and the left and right inner portions of the table 2 respectively have track grooves 1a and 2a having a substantially V-shaped cross section, that is, tracks formed along the longitudinal direction. There is.
And the bed 1 and the table 2 are
The bed 1 is arranged inside the table 2 so that a and 2a face each other.

A cage 5 having a substantially rectangular plate shape and a long shape is interposed between the raceway grooves 1a and 2a. The cage 5 is made of metal, synthetic resin, synthetic rubber or the like.

As shown in the figure, a plurality of circular openings 5a are formed in the retainer 5 in a line along the longitudinal direction, and balls 6 as rolling elements are freely rotatable in each of the openings 5a. Has been inserted into. These balls 6 are on the bed 1
And, with the relative movement of the table 2, it rolls on the raceway grooves 1a and 2a. As shown in FIG. 1, both front and rear end portions of the bed 1 and the table 2 (however, in the drawing, the bed 1
And only one end of the table 2 is shown), end caps 7 and 8 for preventing the retainer 5 and the balls 6 from coming off are provided.

The rolling guide unit having the above structure is arranged on a base (not shown) provided in a device such as an industrial robot, and the bed 1 serves as a base when the table 2 is used as a movable side. Fixed against.

In this embodiment, the rolling guide unit of the type in which the balls 6 are rolled while being aligned and held by the cage 5 is shown, but a rolling guide having a circulation path through which the balls circulate is shown. Of course, the present invention can be applied to other types such as a unit. Although balls are used as the rolling elements in this embodiment, rollers may be used. Further, in the rolling guide unit of the present embodiment, the relative movement of the bed 1 and the table 2 is performed linearly, but it may be configured so as to be curved relative movement having a certain curvature.

Next, the primary side and the secondary side of the movable magnet type linear DC motor as the driving means for relatively driving the bed 1 and the table 2 will be described. In this embodiment, a moving magnet type linear DC motor is used as the driving means. However, a moving coil type linear DC motor or a linear motor other than the linear DC motor can be used, and other completely different principles. It is also possible to adopt the driving means of. However, in the present embodiment, since the linear motor is adopted and the linear motor is compactly incorporated in the inside of the rolling guide unit, the miniaturization of the entire drive unit, especially the thinning is achieved.

Now, as shown in FIGS. 1 and 2, on the primary side of the linear DC motor, a rectangular plate is provided so as to extend along the inner bottom surface of the bed 1 and over substantially the entire length of the bed 1. -Shaped coil yoke 12 and a large number of armature coils 14 attached to the upper surface of the coil yoke 12 in a line along the direction in which the table 2 should move.
And have. Each armature coil 14 is wound in a rectangular ring shape.

As shown in FIG. 2, a Hall effect element 16 is provided on one side of the upper surface of the coil yoke 12. On the surface of the coil yoke 12, wiring for electrically connecting an external drive circuit (not shown) and the Hall effect element 16 is provided by etching or the like. However, the wiring and the coil yoke 12 are electrically insulated from each other.
The drive circuit is for supplying power to each of the armature coils 14 described above. Hall effect element 1
Six armature coils 6 are provided in the same number as the armature coils 14 provided, and one armature coil 6 is disposed for each armature coil 14.

Each Hall effect element 16 generates a signal according to the amount of magnetic field lines generated by the field magnet when a field magnet provided on the secondary side (described later) approaches. Based on this signal, the power supply to the armature coils 14 and the disconnection thereof are controlled.

On the other hand, the secondary side is constructed as follows.

As shown in FIGS. 1 and 2, the secondary side is
Magnet yoke 17 fixed to the lower surface side of the table 2
And a field magnet 18 fixed to the lower surface of the magnet yoke 17 so as to face each of the armature coils 14 on the primary side. As shown in FIG. 3, the field magnet 18 is formed in a substantially rectangular plate shape as a whole, and along the direction A in which the relative movement of the primary side and the secondary side is made,
A plurality of N and S magnetic poles are arranged and magnetized so that five poles in this case are alternately arranged. Note that, depending on the case, one pole may be provided without providing the plurality of magnetic poles.

In the linear DC motor having such a structure, by supplying a predetermined current to the armature coil 14, a thrust force based on Fleming's left-hand rule is generated between both the primary side and the secondary side. If the combined bed 1 is the fixed side, the table 2 integrated with the secondary side moves as the movable side by this thrust.

In the present embodiment, the primary side is connected to the bed 1 and the secondary side is connected to the table 2. However, conversely, the secondary side is connected to the bed 1 and the primary side is connected to the bed 1. May be combined with Table 2.

Next, the structure of the relative position detecting means for detecting the relative position of the bed 1 and the table 2 and the control system for controlling the relative position of the bed 1 and the table 2 on the basis of the detection signal generated by the relative position detecting means will be described. To do.

As shown in FIG. 2, a detected portion 21 is provided on one inner surface of the bed 1 along the track groove 1a of the bed 1 over substantially the entire length of the bed 1.
Then, a small case 23 containing a detecting means (described later) for detecting the detected portion 21 is provided so as to face the detected portion 21, and is attached to the lower surface of the table 2 via a small bracket 22. It is installed.

The detected portion 21 is composed of a magnetic film and is formed by magnetizing the magnetic film as follows. The magnetic film is formed by applying a molten magnetic agent to the inner surface of the bed 1 and solidifying it. However,
The magnetic film may be formed by plating or sputtering instead of applying the magnetic agent in this way, or by attaching a magnetic member formed in advance in a thin film shape with an adhesive or the like. It is also possible to form the detected part 21 by directly magnetizing the surface layer of the bed 1 itself without forming a magnetic film.

FIG. 4 shows the detected part 21 in detail.

As shown in the figure, the detected portion 21 is magnetized in multiple poles along the longitudinal direction. In this case, Table 2 above
The magnetic poles of N and S are finely and alternately arranged and magnetized at equal pitches for position detection. In FIG. 4, each magnetized portion is indicated by reference numeral 26, but the non-magnetized portion is indicated by reference numeral 27 with hatching (by dots). As shown in the figure, these magnetized portions 26 have boundaries 2 in their respective alignment directions.
6a is perpendicular or substantially perpendicular to the alignment direction. It should be noted that the magnetized portion 2 as an origin serving as a measurement reference corresponds to the one located at the extreme end of the magnetized portions 26.
8 are provided.

On the other hand, the detecting means provided in the case 23 for detecting the detected portion 21 is composed of the following magnetic sensors.

That is, as shown in FIG. 4, two magnetoelectric conversion elements 29 and 30 such as Hall effect elements provided for detecting each magnetized portion 26 and the magnetized portion 28 serving as the origin are detected. Magnetoresistive element (MR element) 2 for
5 and.

The magnetoelectric conversion element 30 is the magnetoelectric conversion element 2
9 is provided with a shift of 1/2 of the pitch P between the magnetized portions 26, whereby a waveform having a phase difference of π / 2 with respect to the waveform shown in FIG. 6A is obtained. . As shown in FIG. 6, the waveforms obtained by the magnetoelectric conversion element 29 and the magnetoelectric conversion element 30 are positive and negative continuous sine waves with the O level as a reference, but as shown in FIG. Amplification processing is performed so that the O level is changed to the Vmax level by passing through the signals 31 and 31b. This is to facilitate signal processing in the subsequent stage.

Next, the structure of the control system for controlling the position of the table 2 based on the detection signal generated by the above-mentioned detection means will be described.

As shown in FIG. 5, the waveforms output from the magnetoelectric conversion element 29 and the magnetoelectric conversion element 30 are amplified by the amplifier circuit 31a.
And 31b. The amplifier circuits 31a and 31
b is the A / D conversion circuits 32a and 32b, the latch circuit 3
3a and 33b and a multiplexer (MPX) 34 are sequentially connected, and the output of the multiplexer 34 is input to a CPU (control circuit) 35. Also, C
A memory (ROM) 37, an up / down counter 38 as counting means, and a D / A conversion circuit 39 are connected to the PU 35.

The A / D conversion circuits 32a and 32b are
The latch circuit 3 converts the analog waveform whose level is amplified by the amplifier circuits 31a and 31b in the preceding stage into binary data.
Input respective data into 3a and 33b. The latch circuits 33a and 33b correspond to the A / D conversion circuit 32a at the preceding stage.
And 32b, the data of the A / D conversion circuits 32a and 32b are latched and held in order to synchronously process the data which is converted every second. The held data is input to the multiplexer (MPX) 34. Since the multiplexer (MPX) 34 cannot output the data latched by the latch circuits 33a and 33b at the same time when outputting to the CPU 35 in the subsequent stage, the multiplexer (MPX) 34 performs time-division processing and outputs the data separately to the CPU 35 to perform arithmetic processing. Is done.

Next, the arithmetic processing of the CPU 35 will be described.

First, as an initial operation, the table 2 is driven to move to the reference position, and the magnetoresistive element 25 stores it in the memory (RAM) 40 in response to a signal generated by detecting the magnetized portion 28 which is the origin. Scale position data is reset. This reset command causes the table 2 to start moving to a desired position. In response to this, the magnetoelectric conversion element 29 and the magnetoelectric conversion element 30 are used to generate the magnetic field shown in FIGS.
A continuous waveform having different levels and having different phases is obtained as shown in FIG.

As shown in FIGS. 6A and 6B, regarding the area m, for example, the output data of the magnetoelectric conversion element 29 and the magnetoelectric conversion element 30 are the same as those in FIGS. 6A and 6B. It can be seen that the corresponding waveforms are different. As a result, CP
U35 can determine the moving direction of the table 2 by comparing the different data.

Next, the movement amount of the table 2 is obtained as follows.

That is, in FIG. 4, the magnetoelectric conversion elements 29, 30 and the magnetoresistive element 25 provided in the case 23 are provided.
Letting S be the amount of movement with respect to the detected part 21, this is the amount of movement of the table 2.

The movement amount S of the, for example, as shown in (A) and (B) in FIG. 6, outputs V _A magnetoelectric conversion element 29, and the output of the magnetoelectric converting element 30 and V _B, V _A /
The voltage ratio of V _B is determined. This is because, for example, a voltage of α × V _A and α × V _B can be obtained by changing the gap between the magnetoelectric conversion element 29 and the magnetoelectric conversion element 30 and the magnetized portions 26 to be detected by these. Even if such a gap changes, there is a risk that the arithmetic processing will be performed as if it had moved. Therefore, if processing is performed as α × V _A / α × V _{B in} order to prevent such a mechanical error, α can be obtained as V _A / V _B as having no relation to the position data.

However, since the fine position data within one pitch (P) corresponding to V _A / V _B is previously stored in the memory 37, the CPU 35 is obtained by the above arithmetic processing. The distance α shown in FIG. 4 can be obtained by reading the value having a value equal to the value of V _A / V _B from the memory (ROM) 37 and comparing the values. The position data of the obtained distance α is already stored in the memory 40 (not stored at the time of the first writing from the reference position), so that the position data obtained before that is stored. The CPU 35 adds the distance α obtained this time after the reading, and writes the distance S calculated by this as the position data in the memory 40.

The distance S is stored in the memory 40 as position data by repeating such arithmetic processing.

By the way, the CPU 35 is connected to an up / down counter 38 for up / down a pulse given by a control means (not shown). The up / down counter 38 is constructed so as to operate in response to a reset command of the memory 40, and the counter 1 shown in FIG.
Since the number of pulses generated in the pitch (P) has been obtained in advance, the CPU 35 counts the number of pulses output from the up / down counter 38 to calculate the distance S ′.
Can be calculated.

The required distance S'and the memory 40
The deviation amount is obtained by comparing the distance S stored in the memory.
The CPU 35 uses the obtained deviation amount as the D / A converter 39.
To output. The table 2 is driven to the regular position based on this output.

As is apparent from FIG. 4, in the present embodiment, the magnetized portions 26 to be detected by the magnetoelectric conversion elements 29 and 30 are formed without a gap therebetween. The pitch P between the magnetized portions 26 may be set large by interposing a non-magnetized portion therebetween.

Next, a drive unit as a second embodiment of the present invention will be described with reference to FIG. 1 to 5 except the part described below.
Since it has the same structure as the drive unit as the first embodiment shown in FIG. 1, only the main part will be described. Further, in the following description, the same reference numerals are given to the same or corresponding components as those of the drive unit as the first embodiment. The same applies to the third embodiment described later.

As shown in the figure, in the present embodiment, each magnetized portion 26 for detecting the movement amount has a non-magnetized portion 2 between them.
It is provided with 7 in between. In this case, the size of the non-magnetized portion 27 in the alignment direction of the magnetized portions 26 is the same as that of the magnetized portion 2.
It is set to the same as 6.

Each magnetized portion 26 is magnetized so that one side in the direction perpendicular to the direction in which it is aligned becomes the N pole and the other side becomes the S pole.

In such a construction, in the construction of the first embodiment described above, magnetic flux is generated between the adjacent magnetized portions 26, whereas the magnetic flux is the N pole of each magnetized portion 26. , S pole. However, although the density of the magnetic flux is maximum in the central portion in the direction in which the magnetic flux is aligned in each of the magnetized portions 26, the density of the magnetic flux is gradually weakened but reaches the range of the adjacent non-magnetized portions 27 so that the central portion of the non-magnetized portions 27. It is the smallest in the department. Therefore, each magnetoelectric conversion element 29, 3
The waveform obtained by 0 is also a positive / negative continuous sine wave, and the position of the table 2 can be detected based on the same measurement principle as in the first embodiment.

FIG. 8 shows the essential parts of a drive unit as a third embodiment of the present invention. In each of the drive units as the first and second embodiments described above, the bed 1
Magnetism is used as a means for detecting the position of the table 2 with respect to (see FIGS. 1 and 2), but in the drive unit, an optical means is used as the detection means.

That is, in the drive unit,
The detected portion 51 provided on the fixed side over substantially the entire length of the bed 1 is made of a light reflecting film. The light-reflecting film is formed by vacuum-depositing chromium on the surface of the bed 1. However, materials other than chrome may be used. The light-reflecting film may be formed by coating, plating or sputtering instead of vapor deposition, or by attaching a light-reflecting member formed in advance in a thin film form with an adhesive or the like. Good. Further, the detected portion 51 may be formed by forming a mirror-finished surface of the bed 1 itself without forming the light reflection film.

FIG. 9 shows the detected part 51 in detail, but as can be clearly understood from the figure, the detected part 5 is detected.
1 is two kinds of parts 52 and 5 having different light reflectances.
3 are arranged alternately along the longitudinal direction and at an equal pitch. The high reflectance portion 52 is, for example, in a mirror surface state, the light reflectance is, for example, close to 100%, and the low reflectance portion 53 is formed into a rough surface state by etching or the like to cause irregular reflection, and a predetermined direction. The light reflectance of the light is, for example, 20 to 30%. As is clear from FIG. 8, a small low reflectance portion 54 as an origin serving as a measurement reference is provided corresponding to the low reflectance portion 53 located at the end.

On the other hand, the detection means attached to the movable table 2 for detecting the detected portion 51 is composed of the optical means configured as described below, and emits light to the detected portion 51. When the light is emitted, the reflected light is received and a signal based on the reflected light is emitted.

As shown in FIG. 8, the optical means comprises a micro encoder 55.
Has the total reflection mirror portions 56c on the left and right, and has the above-mentioned detected portion 51.
U-type semiconductor laser 56 that irradiates light from both ends 56a and 56b toward the target, a photodiode 58 that receives the reflected light from the detected portion 51 and emits an output voltage based on the amount of the reflected light, and the U-shaped It has a microlens 59 as a total of three collimator lenses disposed on the light irradiation side of the semiconductor laser 56 and the light receiving side of the photodiode 58, respectively. As shown in FIG. 8, the micro encoder 55 includes one for detecting the detected portion 51 and one for detecting the low reflectance portion 54 provided as a measurement reference. Two are juxtaposed. Also, FIG.
In the above, reference numeral 60 indicates each of the micro encoders 5.
5 shows a metal block made of copper or the like that is attached to the back side of 5 and acts as a heat sink.

For details of the configuration of the micro encoder 55 and a method of manufacturing the same, see pages 126 to 131 of "Applied Mechanical Engineering" published in April 1991, for example.
Page. In this document, the micro encoder 55 has a size of 0.5 mm square, including the metal block 60 that performs heat dissipation.

As described above, the photodiode 58 included in the one of the pair of micro encoders 55 provided to detect the detected portion 51 has the high reflectance portion 52 and the low reflectance of the detected portion 51. An output corresponding to the amount of reflected light from each of the portions 53 is emitted toward a control unit (not shown), and the control unit determines the output corresponding to the amount of reflected light from the low reflectance portion 53 as a signal. The control unit uses a counter (not shown) to count this signal obtained along with the movement of the table 2 from the measurement reference position with respect to the bed 1 (shown in FIGS. 1 and 2) to obtain a low reflectance. Part 53
The pitch P (shown in FIG. 9) between them is multiplied by this count value to obtain the distance from the measurement reference position (right end position in FIG. 8: position where the low reflectance portion 54 is provided). It should be noted that the fact that the table 2 has reached the measurement reference position is confirmed by detecting the low reflectance portion 54 provided as the origin point by the micro encoder 55 provided further.

Since the output signal of the micro encoder 55 is obtained as a sine wave, like the drive unit using magnetism as the first and second embodiments described above,
A high resolution can be achieved by dividing the sine wave signal for calculation. Further, by providing the two micro encoders offset from each other by 1/2 of the pitch P of each of the low reflectance portions 53, the moving direction can be detected.

Further, in each of the above-described embodiments, the detected portion is provided on the bed 1 side and the detection means for detecting the detected portion is provided on the table 2 side. Conversely, on the contrary, the table 2 side is provided. The detected part may be provided and the detection means may be provided on the bed 1 side. Further, it is needless to say that the parts to be provided with the detected part and the detection means are not limited to the parts shown in the above-mentioned embodiments and may be changed appropriately.

Further, the present invention is not limited to the configurations of the above-described respective embodiments, and various configurations can be realized by appropriately combining or applying the configurations included in the respective implementing sides even if only partially.

Further, in the configuration of position detection utilizing magnetism as in the first and second embodiments described above, the table 2
Although the two magnetoelectric conversion elements 29 and 30 are used for the purpose of determining the moving direction of, the number may be one if it is not necessary to determine the moving direction.

Further, when the resolution of the movement detection of the table 2 is not so high, the value of α shown in FIGS. 4 and 7 is not calculated, and the detected magnetic peak value is simply calculated by the counter. Just doing is enough.

[0064]

As described above, according to the present invention,
Since the detected portion forming the relative position detecting means for detecting the relative position of the first and second relative moving members is arranged in the relative moving member as a thin film, for example, the relative position detecting means is The occupying space is substantially limited to the occupying space of the magnetic sensor or the like serving as the detecting means, and can be kept extremely small, which has the effect of contributing to downsizing of the industrial robot or the like to be incorporated. Further, since a separate linear scale or the like which has been conventionally used is not required, there is an effect that cost reduction can be achieved. Further, according to the present invention, since only the constituent members of the rolling guide unit are mechanically interposed between the detected portion and the detecting means, an error in assembling these members causes relative position detection accuracy. Is less affected, and the relative positioning of the relative moving members is highly reliable.

[Brief description of drawings]

FIG. 1 is a perspective view including a partial cross section of a drive unit as a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the drive unit shown in FIG.

3 is a perspective view of a field magnet included in the drive unit shown in FIGS. 1 and 2. FIG.

FIG. 4 is a side view showing a detected part provided in the drive unit shown in FIGS. 1 and 2 and a detection means for detecting the detected part.

FIG. 5 is a block diagram of a control system that controls the operation of the drive unit shown in FIGS. 1 and 2.

FIG. 6 is a diagram showing a waveform obtained by a magnetoelectric conversion element included in the drive unit shown in FIGS. 1 and 2.

FIG. 7 is a side view showing a detected part provided in a drive unit as a second embodiment of the present invention and a detection means for detecting the detected part.

FIG. 8 is a perspective view showing a detected part provided in a drive unit as a third embodiment of the present invention and a detection means for detecting the detected part.

9 is an enlarged view of a portion A in FIG.

FIG. 10 is a perspective view including a partial cross section of a conventional small-sized thin-walled rolling guide unit.

[Explanation of symbols]

1 bed (first relative moving member) 2 table (second relative moving member) 1a, 2a raceway groove (raceway) 5 cage 6 ball (rolling element) 14 armature coil 18 field magnet 21 detected part 25 Magnetoresistive element 26 Magnetized part 27 Non-magnetized part 28 Magnetized part (origin) 29, 30 Magnetoelectric conversion element 51 Detected part 52 High reflectance part 53 Low reflectance part 54 Low reflectance part (origin) 55 Micro encoder 56 U type semiconductor laser 58 Photo diode 59 Micro lens

Claims (20)

[Claims] 1. A first relative movement member having an orbit along its relative movement direction on an outer side thereof, and a cross-sectional shape perpendicular to the relative movement direction being substantially U-shaped. A second relative moving member provided on the outside and having a raceway corresponding to the raceway on the inner side thereof; and a rolling element interposed between the raceways, and one of the relative movement members has the above-mentioned structure. A small-sized thin-walled rolling guide unit characterized in that a detected part is provided along the track, and a detection means for detecting the detected part is provided on the other side. 2. The detection part is made of a magnetic film, is multi-polarized to the magnetic film along the track, and the detection means is a magnetic sensor. Small thin-walled rolling guide unit. 3. The small-sized rolling guide unit according to claim 2, wherein the magnetic film is formed by applying a magnetic agent. 4. The small-sized thin-walled rolling guide unit according to claim 2, wherein the magnetic film is formed by adhering a magnetic member formed in a thin film beforehand. 5. The small-sized thin-walled body according to claim 1, wherein the detected portion is formed by magnetizing the relative moving member itself along the track with multiple poles, and the detecting means is a magnetic sensor. Rolling guide unit. 6. The magnetic poles according to claim 2, wherein different magnetic poles are alternately arranged along the orbit and magnetized.
The small thin rolling guide unit according to any one of the above. 7. A plurality of magnetized portions are arranged in parallel along each of the orbits with a non-magnetized portion interposed therebetween, and one side in a direction perpendicular to the direction in which the magnetized portions are arranged. To N
The small-sized thin-walled rolling guide unit according to any one of claims 2 to 5, wherein the pole and the other side are magnetized as S poles. 8. The small-sized thin-wall rolling guide unit according to claim 2, wherein the magnetic sensor comprises a magnetoelectric conversion element. 9. The small-sized thin-walled rolling guide unit according to claim 2, wherein the magnetic sensor comprises a magnetoresistive element. 10. The portion to be detected has portions having different light reflectances arranged alternately along the track, and the detection means includes optical means for emitting light and receiving reflected light. The small-sized thin-walled rolling guide unit according to claim 1. 11. The small-sized thin-walled rolling guide unit according to claim 10, wherein the detected portion is made of a light reflecting film. 12. The small-sized thin-walled rolling guide unit according to claim 11, wherein the light-reflecting film is coated with a light-reflecting agent. 13. The small-sized thin-walled rolling guide unit according to claim 12, wherein the light reflecting agent is made of chromium and is vapor-deposited. 14. The small-sized thin-walled rolling guide unit according to claim 11, wherein the light-reflecting film is formed by adhering a light-reflecting member formed in advance in the form of a thin film. 15. The small-sized thin-walled rolling guide unit according to claim 10, wherein the detected portion is formed on the relative moving member itself. 16. The optical means includes: a semiconductor laser that irradiates the detected portion with light from both ends; and a photodiode that receives reflected light from the detected portion and emits a signal based on the reflected light. 16. The small-sized thin wall structure according to claim 10, further comprising an optical microencoder having a microlens disposed on the light irradiation side of the semiconductor laser and the light receiving side of the photodiode. Rolling guide unit. 17. The origin according to claim 1, wherein the detected portion has an origin serving as a measurement reference.
The small-sized thin-walled rolling guide unit according to any one of 6. 18. A first relative movement member having an orbit along the relative movement direction on the outer side thereof, and a cross-sectional shape perpendicular to the relative movement direction having a substantially U shape, A second relative movement member provided on the outside and having a raceway corresponding to the raceway on the inner side, a rolling element interposed between the raceways, and the first and second relative movement members relative to each other. A detection means for detecting the detected portion is provided on one of the relative moving members along the track, and a detection means for detecting the detected portion on the other side. A drive unit characterized by the above. 19. The driving means comprises a linear motor having a primary side and a secondary side, which are connected to the inside of each of the relative moving members.
The described drive unit. 20. The linear motor is a linear DC motor, the primary side includes an armature coil, and the secondary side is along a relative movement direction with respect to the primary side and faces the armature coil. 20. The drive unit according to claim 19, comprising a field magnet arranged.