JPH11311208A - Rodless linear drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rodless linear drive device provided with a position detecting means which can be manufactured with ease and mounted with ease. SOLUTION: This linear drive device 1 is provided with a housing 3 having an internal space 2, and a drive section 3 operates in the longitudinal direction of the housing 3. The housing 3 has a long hole 12 opening to the internal space 2, and a drive section 13 is provided with a drive part 14 provided in the internal space 2 and a carrier part 15 extending outside from the long hole 12. The long hole 12 is blocked by a sealing band 43. The rodless linear drive device 1 is provided with a position detecting means 58 to detect the relative positions of the drive section 13 and the housing 3. The position detecting means 58 is provided with a housing side detecting means 59 provided in the sealing band 59 and a drive section side detecting means 60, and an evaluation device 64, which is connected to the detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rodless linear drive provided with position detecting means for detecting a relative position between a drive unit and a housing.

[0002]

2. Description of the Related Art A rodless linear drive device provided with a position detecting means for detecting a relative position between a drive unit and a housing includes:
For example, German Patent Publication (utility model) 29, 508, 517
U. In this drive device, detection means cooperating with each other is provided on the housing side and the drive unit side. Specifically, the housing-side detecting means is two resistance bands provided on each side surface of the elongated hole provided in the housing, and the driving-side detecting means is provided on a carrier portion contacting the two resistance bands. It is a provided wiper contact. And
An evaluation device is connected to the resistance band on one side and detects or measures the resistance of the two shorted areas of the resistance band due to the wiper contacts. Since this resistance changes depending on the position of the contact, the relative position of the output drive unit and the housing can be detected from this resistance.

[0003]

However, such a rodless linear drive requires a relatively long time to manufacture, since it is necessary to dispose both the resistance band and the wiper contact in the long hole of the housing. That is, since the space for providing the resistance band and the wiper contact is small, it is necessary to perform high-precision manufacturing so that the driving unit cannot be moved along the housing in the long hole. Also,
When the housing is made of a conductive material, it is troublesome because the housing must be insulated from the resistance band.

[0004] It is an object of the present invention to provide a rodless linear drive device provided with a position detecting means which can be easily mounted and can reduce the manufacturing cost.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, a rodless linear drive device according to the present invention includes a housing having a long hole opened in an internal space, and a drive portion provided in the internal space so as to be movable in a longitudinal direction. A drive unit having a carrier portion extending outward through the slot, and position detecting means for detecting a relative position between the drive unit and the housing, both sides in a longitudinal direction of the slot. A rodless linear drive device in which at least a longitudinal region adjacent to the drive unit is closed by a seal band, wherein the position detection unit has a first detection unit in one of the housing and the drive unit, and the other An evaluation device is connected to at least one of the first detection means and the second detection means, and the detection means on the housing side is provided on the seal band. It is characterized in that is.

In the above configuration, at least the carrier portion of the driving portion projects outward from the long hole, and the seal band is provided inside the housing at a distance from the long hole. The detection means on the drive unit side can be provided so as to act on the area of the seal band provided at a distance from the slot, and since there is sufficient space, the detection means can be easily assembled to the drive unit. is there. When manufacturing the seal band, the housing-side detecting means may be provided on the seal band.
For example, the housing-side detection means can be incorporated at the time of extrusion of the seal band as in the case of manufacturing an insulated cable or wire. In this case, when the seal band is attached to the housing of the rodless linear drive device, the housing-side detecting means can be attached at the same time, so that the time and labor required for manufacturing the linear drive device are reduced.

[0007] The seal band may comprise at least one reinforcing cord extending in the direction of the entire seal band and provided in or on the seal band, in which case the code is part of the housing-side detection means. As a conductor. Preferably, the first and second detection means are provided so as to cooperate in a non-contact state.

In addition, when the housing and the drive unit move relative to each other, the first detecting means is provided so as to generate a changing magnetic field adjacent to the second detecting means, and the second detecting means generates a magnetic field detection signal, The magnetic field detection signal may be supplied to an evaluation device for detecting the relative position.

The first detecting means may include a plurality of conductive and / or magnetizable or permanent magnet detecting elements, and the detecting elements may be provided continuously in the direction of relative movement of the drive and the housing. The second detecting means may include at least one magnetic field sensor.

Further, the second detecting means may include a coil device. In this case, the magnetic field existing in the coil device is generated by the coil device itself. The coil device has at least one detection coil that generates a detection signal and is connected to the evaluation device. The detection coil is part of the oscillation circuit, and the evaluator checks the relative position by changing the tuning of the oscillation circuit.

Further, the evaluation device may transmit the detection signal by the first detection means and detect the relative position by using the detection signal and cooperating with the second detection means.
In the evaluation device, the relative position may be detected as a function of the time elapsed between the transmission of the detection signal and the reception of the response signal generated by the second detection means.

The first detecting means may include a conductor array provided on the seal band and extending in the longitudinal direction of the seal band. On the other hand, the second detecting means may be provided in the driving unit, the discontinuous point may be generated in the conductor row, the detection signal may generate a response signal at the discontinuous point, and the response signal may be returned to the evaluation device. In this case, the response signal at the discontinuous point is constituted by the reflection of the detection signal.

Further, the second detecting means may include magnet means, and the magnetic field of the magnet means may act on the conductor row to form a discontinuous point. At least one conductor of the conductor row may have magnetostrictive characteristics. In addition, the conductor is a magnetostrictive and microcrystalline or amorphous conductor and has conductivity, and a detection signal is transmitted by the conductor to generate a mechanical wave at a discontinuous point, and the mechanical wave is returned to the evaluation device. A signal may be formed.

The magnetostrictive conductor may be a tubular sound conductor, and is preferably provided coaxially with an electric detection conductor for transmitting a detection signal, and a mechanical wave is generated at a discontinuous point by the transmitted detection signal. The mechanical wave is sent back to the evaluation device. The conductor array provided on the seal band includes at least one conductor accessible from the outside, the second detecting means includes conductor tap means in contact with the conductor, and the contact between the conductor tap means and the conductor is not provided. A continuous point may be formed. Further, the conductor tap means may electrically connect a plurality of conductors in the conductor row at discontinuous points.

In the present invention, the evaluation device may be connected to only the first detecting means or the second detecting means.
Further, the first detecting means may be provided on the seal band, and the second detecting means may be provided on the drive unit.

In the present invention, the evaluation device may be connected only to the housing-side detecting means. In this case, the connection between the housing-side detection means and the evaluation device is made adjacent to the point of attachment of the seal band to the housing.
The rodless linear drive according to the invention is provided for drive purposes, the drive part being a piston.

As mentioned above, the evaluation device can only be connected to the first or second detection means. In this case, since the detection unit on the side to which the evaluation device is not connected does not require a connection unit to the evaluation device, the structure is simplified and the device can be easily manufactured. Also, since the first and second detection means can cooperate without contacting each other, the driving unit and the housing relatively move without hindrance,
Friction due to contact between the first and second detection means can be prevented.

In such a structure, when the housing and the drive unit move relative to each other, the first detecting means generates a magnetic field which fluctuates effectively, for example, adjacent to the second detecting means, and the second detecting means generates a magnetic field detection signal. And this signal is supplied to an evaluation device for detecting the relative position. Such a position detecting means can perform a reliable function without increasing the manufacturing cost.

In the first detecting means, a plurality of conductors and / or magnetizable or permanent magnet detecting elements are provided, for example, at regular intervals in the direction of relative movement between the drive unit and the housing. The detection means having such a structure is easy to manufacture. Further, the second detecting means includes a coil device. Further, the second detecting means can be used as a magnetic field sensor. Further, an effective magnetic field adjacent to the coil device can be generated by the coil device itself.
Therefore, since the first detecting means does not need to generate an effective magnetic field in the coil device structure, a material which is inexpensive and has no permanent magnetism, preferably a conductive material, is used for manufacturing the first detecting means. can do.

When the evaluation device is connected only to the first detection means, the evaluation device transmits a detection signal via the first detection means, and uses the detection signal to cooperate with the second detection means to thereby make a relative detection. Detect the position. By using such a detection signal, the relative position can be detected even if the initial positions of the housing and the drive unit before the relative movement are unknown.
Therefore, it is not necessary to set an initial position in the evaluation device in order to detect the relative position. The relative position can be easily detected by the detection signal and the second detection means in the evaluation device based on the elapsed time between the transmission of the detection signal and the arrival of the response signal generated by the detection signal.

Further, the evaluation device can be connected to the housing side detecting means. Usually, the drive moves along the fixed housing, so that the connecting cable to the evaluation device in this case does not need to move. Furthermore, since the first detection means is provided on the seal band and includes a conductor row extending in the longitudinal direction of the seal band, transmission of the detection signal and the response signal is easy. In this case, since the second detecting means can be provided in the driving section, a discontinuous point is formed in the conductor row, and at the discontinuous point, the detection signal generates a response signal, and the response signal is returned to the evaluation device. Therefore, the relative position of the drive and the housing is determined by the discontinuity. The response signal is preferably a reflection of the detected signal at the discontinuity, ie an echo of the signal. The reflection is easily performed by the second detection means.

For this purpose, the second detecting means comprises a magnet means, and its magnetic field acts on the conductor row to form a discontinuity.
Preferably, at least one conductor of the conductor array has a magnetostrictive property, so that the conductor is deformed by the action of a magnetic field, which forms a discontinuity. Furthermore, the conductor row can comprise at least one conductor that is accessible from the outside. In this case, the second detecting means includes a conductor tap means for contacting the conductor, and a contact point between the conductor tap means and the conductor forms a discontinuous point. At the tap point of the conductor, the resistance of the conductor in view of the transmission signal can easily change, and reflection occurs at the discontinuity. According to a modification of the present invention, a plurality of conductors of the conductors are electrically connected at the discontinuous points by the conductor tap means. The conductor tap point is a short circuit jumper.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. It is needless to say that the embodiments of the present invention are not limited to the above-mentioned embodiments, but can take various forms as long as they belong to the technical scope of the present invention.

As shown in FIG. 1, the rodless linear drive device 1 according to the present embodiment has a housing internal space 2 defined by a housing 3. The cylindrical housing body 5 provided in the housing 3 extends in the longitudinal direction 4, and its ends 6 and 7 are closed by housing end plates 8 and 9, respectively. A long hole 12 is provided in the housing body 5, and the long hole 12 penetrates the housing body 5 in the radial direction from the outer periphery thereof to open into the internal space 2 of the housing 3, and extends along the entire length of the housing body 5. Direction 4
Extends to.

The driving unit 13 is provided on the housing 3,
It moves longitudinally along the housing 3. Drive unit 13
Has a drive portion 14 provided in the internal space 2 of the housing 3 so as to be movable in the longitudinal direction, and a carrier portion 15 extending outward from the elongated hole 12. The drive portion 14 constitutes a portion for transmitting power of the drive portion 13, and the carrier portion 15, for example, mounts a tool, a workpiece, a sensor, and the like and moves it to a desired position, although not shown in detail. Functions as a transport unit.

In the preferred embodiment of FIG.
That is, the drive portion 14 of the pneumatic linear drive is constituted by the piston 18. The rodless linear drive 1 can also be designed to operate electrically. In this case, the driving part 14 is driven using a lead screw, a toothed belt, a V-belt, or the like.

The piston 18 is provided movably in the longitudinal direction in the internal space 2 of the housing 3. The piston 18 has an elongated tubular piston body 22 whose end regions 23 and 24 are closed by substantially cylindrical piston end members 25 and 26, respectively. In the piston body 22, a piston internal space 27 is formed between the two piston end members 25 and.

The piston 18 is connected to the inner wall 3 facing the internal space 2 of the housing 3 via the piston end members 25 and 26.
0 is fitted with a seal. For this purpose, the piston end members 25 and 26 are provided with seal structures 31 and 32 extending in the circumferential direction. These seal structures 31 and 32 are constituted by seal rings. Also, housing 3
The guide rings 33 are provided on the piston end members 25 and 26 so that the piston 18 can be easily guided in the internal space 2.
And 34 are provided.

In the internal space 2 of the housing 3, fluid chambers 37 and 38 are formed on both sides of the piston 18 in the longitudinal direction 4. Fluid chambers 37 and 38 are defined on the one hand by housing end plates 8 and 9 and on the other hand by piston end members 25 and 26. In order to supply and discharge fluid to and from the fluid chambers 37 and 38, the center of the housing end plates 8 and 9 is provided with a fluid duct 3 passing therethrough.
9 and 40 are provided. Fluid chambers 37 and 38
Fluid ducts 39 and 40 are in fluid communication, respectively, and the fluid ducts 39 and 40 are connected to a suitable duct, which is connected to a source of fluid or a means for receiving discharged drive fluid.

The portions adjacent to the long holes 12 of the two fluid chambers 37 and 38 are closed by a seal band 43. The seal band 43 is provided so as to be able to abut the slopes 44 and 45 (see FIG. 2) of the regions 46 and 47 extending in the longitudinal direction along the fluid chambers 37 and 38 in the long hole 12. In other words, as shown in FIG. 2, the seal band 43 preferably has a trapezoidal cross-sectional shape, and both side surfaces 48 and 49 are formed obliquely with respect to each other, and narrowed radially outward. Contact a large area.

The seal band 43 protrudes inside the elongated hole 12 so that the carrier portion 15 of the drive section 13 can be connected to the drive portion 14 through the connection region 52.
And extends to a lead through opening 53 provided in the driving portion 14. Both ends of the seal band 43 are fixed to the housing 3 adjacent to the housing end plates 8 and 9. The seal band 43 is stretched in the operating direction between the fixed positions 54 and 55 in the housing 3. Since the seal band 43 is usually made of a stretchable sealing material, in order to increase the tensile strength, as shown in FIG. 2, in this embodiment, two reinforcing cords 56 and 5 are used.
7 are continuously provided in the seal band 43. The reinforcement cords 56 and 57 are formed from reinforced plastic or metal. One or two or more reinforcing cords may be provided.
May be provided on the outside. In the case of linear drive not driven by the fluid, the seal band 43 does not have to perform the sealing function unless foreign matter enters the housing 3.

In order to detect the relative position between the drive section 13 and the housing 3, the linear drive device 1 is provided with position detecting means 58 as shown by a chain line in FIG. Drive unit 1
By setting the relative position between the housing 3 and the housing 3, the position of the object provided on the carrier portion 15 can be set as required.

The position detecting means 58 includes a first detecting means 59 provided on the seal band 43 and a second detecting means 60 provided on the drive unit 13 and cooperating with the first detecting means 59. Hereinafter, to distinguish them, the first detecting means 5 is referred to as “housing-side detecting means 59”, and the second detecting means 60 is referred to as “driving-unit-side detecting means 60”.

The housing-side detecting means 59 and the drive-portion-side detecting means 60 are shown by dashed lines in FIG.
The drive-side detection means 60 preferably comprises the drive part 14 or the connection area 5 between the drive part 14 and the carrier part 15.
2 is provided. The housing-side detecting means 59 extends along the entire length of the seal band 43. The drive unit side detecting means 60 is composed of the housing side detecting means 59 and the housing 3.
Cooperate at the upper connection point, which relates to the current relative position of the drive 13 and the housing 3 and is referred to as "detection point 61".
It is called. In the embodiment, the detection point 61 is arranged on the housing-side detection means 59, that is, the seal band 43 extending into the lead through opening 53. The lead through opening 53 may be opened in the piston internal space 27 as shown in FIG. In the present embodiment, a considerable space is provided for providing the drive unit side detection means 60 at the detection point 61. For this reason, the drive part side detection means 60 can be easily attached to the position.

Evaluation device 6 forming part of position detecting means 58
Reference numeral 4 is connected to the housing-side detecting means 59, and receives a signal from the housing-side detecting means 59 and sends a signal to the housing-side detecting means 59. The evaluation device 64 can detect the current relative position between the drive unit 13 and the housing 3 by evaluating the signal.

The evaluation device 64 can be connected to the drive-side detection means 60 in addition to or instead of the housing-side detection means 59. 3 to 6 show examples of the structure and principle of the position detecting means 58 in this case. The operation of the position detecting means 58 in various embodiments will be described in detail with reference to FIGS.

The evaluation device 64 in the embodiment of FIGS.
Is connected only to the drive unit side detection means 60. In the exemplary embodiment, the connection is made by electrical connection conductor 66.
Since the housing-side detecting means 59 and the driving-part-side detecting means 60 cooperate without contacting each other, no further friction or wear occurs during the relative movement between the driving part 13 and the housing 3. In this case, the basic operation principle of the position detecting means 58 is that when the housing 3 and the driving unit 13 move relative to each other, that is, when the seal band 43 and the driving unit 13 move relative to each other, the housing side detecting means 59 detects the driving unit. A fluctuating magnetic field is generated in the means 60, and a magnetic field detection signal generated by the drive unit side detecting means 60 at this time is supplied to an evaluation device 64 for detecting a relative position.

In order to detect a fluctuating magnetic field, the drive-side detecting means 60 comprises at least one magnetic field sensor 67 formed by a coil 68 in the embodiment of FIG. Since the coil 68 is connected to a voltage source via the evaluation device 64, a magnetic field is generated by the coil itself.

The housing-side detection means 59 are formed by magnetizable and / or conductive detection elements 69 spaced along the length of the seal band 43. These detection elements 69 are, for example, metal ball rows as conductor rows provided at intervals. However, since the individual detection elements 69 can be connected to one another, it is substantially easier to incorporate the detection elements 69 into the sealing band 43 during manufacture. For example, the detection elements 69 may be combined as a chain or band. The outer shape of the detection element 69 can basically be arbitrarily selected.

The coil 68 effectively surrounds the seal band 43 at the detection point 61. The coil 68 moves along the seal band 43 during the relative movement between the drive unit 13 and the housing 3. When the detection element 69 moves in the coil 68, the magnetic flux changes and the coil 68 generates an induced electromotive force. This magnetic flux can be measured by the evaluation device 64. According to the voltage signal of the coil 68, the driving unit 13 and the housing 3
Relative displacement, ie, displacement, can be measured. The evaluation device 64 can detect the current position of the drive unit 13 and the housing 3 based on a displacement from a known start position.

Further, by providing the detection element 69 on the seal band 43, it is possible to detect the displacement, that is, the travel distance, and also detect the direction of the relative movement. The detection elements 69 may be arranged at irregular intervals from one another, in which case the signal detected by the evaluation device 64 as the voltage on the coil 68 changes periodically in level, and the cycle of the voltage depends on the direction of movement. different. The periodically repeated voltage cycle, which may be said to consist of a directional code, can be caused by having a different detection element 69 in the part of the seal band 43. The fact that the detection elements 69 are different from each other indicates that the coils 68
At different levels of the coil voltage.

In the embodiment of the position detecting means 58 shown in FIG.
However, as long as the detection coil is connected to the evaluation device 64 and generates a detection signal, a coil array may be provided. At least another coil in the coil array may be formed as an excitation coil for generating a magnetic field in the detection coil. In the embodiment of the present invention shown in FIG. 3, the exciting coil and the detecting coil are formed by a single coil 68 at the same time.

The coil may also be a part of the oscillation circuit 73. For example, in a series oscillation circuit, a capacitor 74 and a resistor 75 are provided in an evaluation device 64,
The connection with 8 is made by a connecting lead 66. Needless to say, the capacitor 74 and the resistor 75 may be provided in the drive unit 13 together with the coil 68. If the resistance between the connection conductor 66 and the coil 68 is sufficiently large, the separate resistor 7
5 is not necessary.

When the magnetic flux in the coil 68 changes due to the movement of the detecting element 69 with respect to the coil 68, a change occurs in the resonance frequency, so that the tuning of the oscillation circuit 73 also changes. In this case, a change in the tuning of the oscillation circuit 73 becomes a detection signal, and the evaluation device 64 can detect the displacement (stroke distance) and the current relative position between the drive unit 13 and the housing 3 by this signal.

In the embodiment shown in FIG. 4 which is a modification of the embodiment shown in FIG. 3, the magnetic field sensor 67 of the drive unit side detecting means 60 is, for example, a magnetostrictive sensor or a Hall effect sensor, but other suitable magnetic field sensors may be provided. Can also. The fluctuating magnetic field effectively adjacent to the magnetic field sensor 67 is generated, for example, by the housing-side detecting means 59. As described above, the housing-side detection means 59 provided on the seal band 43 includes the detection elements 69 provided at intervals in the longitudinal direction of the seal band 43. In the present embodiment, the detection element 69 is a permanent magnet.
The sensing elements 69 are preferably connected to each other by a magnetic tape 78. The magnetic tape 78 may be incorporated into the seal band 43 at the time of manufacture, or may be provided outside the seal band 43.

The long cords 79 and 80 connecting the individual detection elements 69 perform the same function as the above-mentioned reinforcement cords 56 and 57 in order to secure sufficient strength in the longitudinal direction of the seal band 43. You can also. Local magnetic field 81 formed by each of the detection elements 69 which are permanent magnets
Is schematically shown in FIG. When the drive unit 13 and the housing 3 move relative to each other, the magnetic field sensor 67
3 and receives a local magnetic field 81 from the sequentially generated detection element 69. The detection signal generated by the sensor 67 at that time is sent to the evaluation device 64 and evaluated to detect the relative position. As described in the above embodiment, since the encoding is performed by designing the arrangement or shape of the detection elements 69 so that the magnitude and direction of the relative motion can be obtained from the detection signal, the current relative position is determined. be able to.

As a modification of the embodiment of FIGS. 3 and 4 described above, the first detecting means 59 may be provided in the driving section 13 to form the driving section side detecting means. In this case, the detecting means of the housing 3 is formed by the second detecting means 60. Further, a plurality of magnetic field sensors 67 may be provided on the seal band 43 at intervals. At this time, the second detection means 60 on the housing side may be formed by a plurality of coils. The first detection means 59 on the drive side may be formed by a permanent magnet or a magnetizable detection element 69. In the case of the magnetic field sensor 67 having the shape of the coil 68, the first detecting means 59 may be formed by the conductive detecting element 69. At this time,
Due to the relative position of the housing 3 and the drive 13, the detection element 69 provided on the drive 13 acts on at least one magnetic field sensor 67 provided on the connection point 61 of the seal band 43 in principle. Since the magnetic field acts on the connection point, that is, the detection point 61, the evaluation device 64 detects which of the magnetic field sensors 67 provided on the seal band 43 is responding, and thereby determines the relative position of the housing 3 and the drive unit 13. You can check.

In this case, the arrangement of the first and second detecting means 59 and 60 in the embodiment of FIGS. 3 and 4 is reversed, the magnetic field sensor 67 is provided on the seal band 43, and at least one detecting element 69 is driven. The unit 13 is provided. An advantage of this modification is that the present embodiment does not detect the current relative position of the driving unit 13 and the housing 3 based on the relative position detected last time and the relative movement performed thereafter, but uses the seal band 4.
3 is to detect the relative position depending on which of the magnetic field sensors 67 provided to the detector 3 responds to the detection element 69 on the drive unit side. As the number of the sensors 67 of the seal band 43 increases, the interval between the sensors becomes narrower, and the relative position between the drive unit 13 and the housing 3 is more accurately detected.

In the above embodiment, the evaluation device 64 of the position detecting means 58 is connected only to the first detecting means 59, and the first detecting means 59 forms a detecting means on the housing side. Therefore, the connection lead 66 is not provided in the drive unit 13. In this embodiment, the housing-side detection means 59 and the evaluation device 64 are connected adjacent to one of the connection points 54 and 55 between the seal band 43 and the housing 3.

As mentioned above, the connection is made by one or more electrical connection conductors 66, but a connection by galvanic separation may be used. For example, the evaluation device 64 and the housing-side detection means 59 may be inductively coupled to each other. The basic principle of the modified example of the position detecting means 58 shown in FIGS.
The evaluation device 64 outputs a detection signal by the housing-side detecting means 59, and the signal is output by the housing-side detecting means 5.
9 and the drive unit side detecting means 60 cooperate to detect the relative position. The detection signal may be of any kind in principle,
For example, a pulse, a pulse train, or a radio wave, particularly an RF wave is preferable.

In this embodiment, the evaluator 64 determines the elapsed time (transmission time) from the transmission of the detection signal to the reception of the response signal to the detection signal by the time taken and the known transmission rate of the detection signal and the response signal. , The relative position between the drive unit 13 and the housing 3 can be directly detected.

When the detection signal is transmitted, the relative position can be directly detected by the evaluation device 64. Drive unit 1
The starting position between the housing 3 and the housing 3 is already
4 does not need to be set because it is known. The current relative position is not directly based on displacement, but is directly detected by evaluating a detection signal or response signal.

The detection signal and the response signal are both the conductor row 8
4 and the conductor row 84 constitutes the housing-side detecting means 59. In this case, the driving unit side detecting means 60
Is a discontinuous point 85 at the detection point 61 together with the conductor row 84
At the detection point 61, the detection signal from the evaluation device 64 generates a response signal to the evaluation device 64.

Here, in order to increase the tensile strength of the seal band 43, the reinforcing cords 56 and 57 may be formed by at least one conductor row 84. In the embodiment shown in FIG. 5, the conductor signal 84 comprises at least one, and preferably two, externally accessible conductors 88 and 89, so that the detection and response signals are present in the form of electrical signals. Can be. The conductors 88 and 89 are preferably provided on one of the outer surfaces of the seal band 43 and have no sealing function. In the preferred embodiment, conductors 88 and 89
Is provided on the back surface 90 of the seal band 43 facing the internal space 2 of the housing 3.

In this case, the discontinuous point 85 is formed because the conductor tap means 91 of the drive section side detecting means 60 is in contact with the conductors 88 and 89. In this case, the contact point is discontinuous point 8
Equivalent to 5. In the variant of FIG. 5, it is also possible to connect only one conductor 88 or 89 to the evaluation device 64. Since the conductor tap means 91 of the drive unit side detection means 60 is formed so as to change the resistance of the conductors 88 and 89 at the discontinuity 85, the transmitted detection signal is reflected and possibly refracted. The reflection forms a response signal to the evaluation device 64. Therefore, as described above, the relative position between the drive unit 13 and the housing 3 can be detected based on the elapsed time from the transmission of the detection signal to the reception of the response signal.

When not only reflection but also refraction occurs at the discontinuity 85, appropriate resistors are used at the ends of the conductors 88 and 89 on the evaluation device 64 side to prevent reflection of the refraction signal. The refraction signal passes through a discontinuity 85 in the direction of propagation of the detection signal at the end of the conductor. In this case, the detection signal is preferably constituted by an electrical pulse.

As mentioned above, in the embodiment of FIG. 5, the two externally accessible conductors 88 and 89 constitute a common wire line pair. In this case, the conductor tap means 91 of the drive unit side detection means 60 is a short-circuit jumper, and short-circuits the two conductors 88 and 89 of the wire wire pair at the discontinuity 85.

In the present embodiment, the wire wire pair is a so-called "Rechel wire", and the detection signal is preferably an RF wave. In this case, the detection signal is completely reflected at the discontinuity 85 and the reflection forms a response signal, which has a 180 degree phase difference from the detection signal. Therefore, a standing wave is formed in the wire line pair. As in the above embodiment, the relative position between the drive unit 13 and the housing 3 is detected by the evaluation device 64 from the transmission time.

FIG. 6 shows a further embodiment of the position detecting means 58.
This will be described with reference to FIG. In this embodiment, the drive unit side detecting means 60 acts on the housing side detecting means 59 without contact. The housing-side detection means 59 is formed by a conductor row 84. The conductor row 84 includes at least one magnetostrictive conductor 96 unlike the above embodiment.

The drive unit side detecting means 60 has a magnet means 94. In the present embodiment, the magnet means 94 is formed by a permanent magnet, and the magnetic field 95 acts on the magnetostrictive conductor 96 of the conductor row 84 to generate a discontinuity point 85. The magnetostrictive conductor 96 is, for example, an amorphous or microcrystalline ferromagnetic conductor. Under the influence of the magnetic field 95, ferromagnetic saturation occurs, and deformation (magnetostriction) of the magnetostrictive conductor 96 occurs. This deformation point constitutes a discontinuity point 85 at which the detection signal transmitted from the evaluation device 64 is reflected and refracted.

First, reflection as a response signal may occur.
The refraction signal transmitted along the magnetostrictive conductor 96 in the propagation direction of the detection signal from the discontinuity 85 is reflected again at the conductor end on the evaluation device 64 side, which may cause an error in the calculation of the relative position. Therefore, since the magnetostrictive conductor 96 is formed so that the end opposite to the evaluation device 64 is terminated by the resistor 97, the reflection coefficient is 0, and the system is matched.

The response signal formed next is based on the amorphous or microcrystalline structure of the magnetostrictive conductor 96. Discontinuity point 85
Produces a mechanical torsional wave, which is simultaneously propagated in both directions.
The mechanical wave returning to the evaluation device 64 is in this case a response signal, the relative position of the housing 3 and the drive 13 being detected by its known propagation speed. The mechanical wave sent from the discontinuity 85 together with the refraction signal to the end of the conductor 96 on the evaluation device 64 side is preferably attenuated at this end, so that substantially no reflection occurs, and the relative position is detected by the evaluation device 64. This can prevent errors in performing the operation.

In such a structure, the evaluation device 6
4, the elapsed time of the detection signal and the response signal is measured,
The relative position between the drive unit 13 and the housing 3 is detected from the elapsed time. FIG. 6 shows a modification of the structure of the position detecting means 58. In this case, the magnetostrictive conductor 96 is shown in FIG.
A tubular acoustic conductor 100 indicated by a dashed line in FIG.
It has the shape of The electric detection conductor 101 provided coaxially with the sonic conductor 100 allows the detection signal to be transmitted to the evaluation device 6.
4 is transmitted. According to the detection signal transmitted to the discontinuity point 85, the first mechanical wave is transmitted through the sound wave conductor 100 to the evaluation device 64.
And the second mechanical wave is transmitted in the opposite direction.
In this case, the mechanical wave is a torsional wave. A response signal is formed by the first mechanical wave, and the second mechanical wave is attenuated at the conductor end to prevent reflection. Unlike the above embodiment, the response signal is not transmitted on the conductor 101 for the detection signal, but is transmitted along a separate conductor 100. Also in this case, the position detection is performed by measuring the elapsed time of the detection signal and the response signal in the evaluation device 64. The principle used in this embodiment is called the “Weedemann effect”.

As is clear from the above embodiment, in the rodless linear drive device of the present invention, the housing-side detecting means of the position detecting means is provided on the seal band, so that the mounting is easy and the manufacturing cost is reduced. Is done.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a fluid-powered rodless linear drive device provided with a position detecting means.

FIG. 2 is a sectional view of the rodless linear drive device taken along line II-II of FIG. 1;

FIG. 3 is a schematic view showing the principle and structure of the position detecting means according to the first embodiment of the present invention, wherein the driving part detecting means includes a coil device and the housing side detecting means includes a plurality of magnetizable detecting elements.

FIG. 4 is a schematic view showing a position detecting means according to a second embodiment of the present invention, similarly to FIG. 3, in which a driving part side detecting means includes a magnetic field sensor and a housing side detecting means includes a plurality of permanent magnet detecting elements. .

FIG. 5 is a schematic diagram showing a position detecting means according to a third embodiment of the present invention, similarly to FIG. 3, wherein the housing-side detecting means includes a conductor accessible from the outside, and the driving-portion-side detecting means comprises a conductor tap means. Including.

FIG. 6 is a schematic view showing a further position detecting means of the present invention in the same manner as FIG. 3, wherein the housing-side detecting means includes a magnetostrictive conductor, and the driving part-side detecting means includes a magnet means.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rodless linear drive device 2 ... Internal space 3 ... Housing 5 ... Housing body
6, 7 ... end portion, 8, 9 ... housing end plate,
12 ... long hole, 13 ... drive part, 4 ... drive part, 15 ... carrier part, 18 ... piston, 22 ... piston body, 23, 24 ... end region , 25, 26 ... piston end member, 27 ...
Piston internal space, 30 ... inner wall, 31, 32
..Seal portions, 33, 34 ... guide rings, 3
7, 38 ... fluid chamber, 39, 40 ... central fluid duct, 43 ... seal band, 44, 45 ... slope, 46, 47 ... longitudinal region, 48, 49 ...
-Side surface, 52 ... connection area, 53 ... lead through opening, 54, 55 ... fixed position, 56, 57
..Strengthening cords, 58 ... Position detecting means, 59,6
0: detection means, 61: detection point, 64: evaluation device, 66: electric connection lead, 67: magnetic field sensor, 68: coil, 69: detection element,
73: oscillation circuit, 74: capacitor, 75
... Ohm resistor, 78 ... Magnetic tape, 79,
80 ... code, 81 ... local magnetic field, 84 ...
・ Conductor row, 85 ・ ・ ・ Discontinuous point, 88, 89 ・ ・ ・ Conductor, 90 ・ ・ ・ Back, 91 ・ ・ ・ Conductor tap means,
94: magnet means, 95: magnetic field, 96: magnetostrictive conductor, 97: resistance, 100: sound wave conductor,
101 ... electric detection conductor

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 591034361 Ruiter Strasse 82, 73734 Esslingen, Germany

Claims (26)

[Claims] 1. A drive unit comprising: a housing having an elongated hole opened to an internal space; a drive portion movably provided in the internal space in a longitudinal direction; and a carrier portion extending outward through the elongated hole. And a position detecting means for detecting a relative position between the drive unit and the housing, wherein a rodless linear drive device in which at least a longitudinal region of the long hole adjacent to the drive unit is closed by a seal band. Wherein the position detection means has a first detection means in one of the housing and the drive unit, and a second detection means in the other, and at least one of the first detection means and the second detection means. And a detection device on the housing side is a rodless linear drive device provided on the seal band. 2. The seal band includes at least one reinforcing cord extending in a longitudinal direction of the seal band and provided in or on the seal band, wherein the reinforcing cord is provided as a detecting means on a housing side. 2. The rodless linear drive device according to claim 1, wherein said rodless linear drive device forms a conductor as a part. 3. The rodless linear drive device according to claim 1, wherein said first detecting means and said second detecting means are provided so as to cooperate in a non-contact manner. 4. The apparatus according to claim 1, wherein said first detecting means generates a changing magnetic field adjacent to said second detecting means during a relative movement between said housing and said driving unit, and said second detecting means is provided with a magnetic field. 4. The rodless linear drive according to claim 3, wherein a detection signal is generated, and the magnetic field detection signal is supplied to the evaluation device for detecting a relative position. 5. The rodless linear drive according to claim 4, wherein the first detecting means includes a plurality of detecting elements, and the detecting elements are provided continuously in a direction of a relative movement between the driving section and the housing. apparatus. 6. The rodless linear drive according to claim 3, wherein said second detecting means includes at least one magnetic field sensor. 7. The rodless linear drive device according to claim 3, wherein said second detecting means includes a coil device. 8. The rodless linear drive according to claim 7, wherein the magnetic field existing in the coil device is generated by the coil device itself. 9. The rodless linear drive according to claim 7, wherein the coil device includes at least one detection coil that generates the detection signal and is connected to the evaluation device. 10. The rodless linear drive device according to claim 9, wherein the detection coil is a part of an oscillation circuit, and the evaluation device confirms the relative position by changing a tuning of the oscillation circuit. 11. The rodless apparatus according to claim 1, wherein the evaluation device transmits a detection signal by the first detection means, and the relative position is detected by using the detection signal and cooperating with the second detection means. Linear drive. 12. The rodless straight line according to claim 11, wherein the relative position is detected as a function of an elapsed time from transmission of the detection signal to reception of a response signal generated by the second detection means. Drive. 13. The rodless linear drive device according to claim 11, wherein the first detecting means includes a conductor array provided on the seal band and extending in a longitudinal direction of the seal band. 14. The method according to claim 14, wherein the second detecting unit is provided in the driving unit, generates a discontinuous point in the conductor row, the detection signal generates a response signal at the discontinuous point, and the response signal is the evaluation signal. 14. The rodless linear drive according to claim 13, which is returned to the device. 15. The rodless linear driving device according to claim 14, wherein the response signal at the discontinuous point is constituted by reflection of the detection signal. 16. The second detecting means comprises magnet means,
15. The rodless linear drive according to claim 14, wherein the magnetic field of the magnet means acts on the conductor row to form the discontinuous point. 17. The rodless linear drive device according to claim 16, wherein at least one conductor of the conductor row has a magnetostrictive characteristic. 18. The method according to claim 18, wherein the conductor is a magnetostrictive and microcrystalline or amorphous conductor and has conductivity, and the detection signal is transmitted by the conductor to generate a mechanical wave at the discontinuous point;
18. The rodless linear drive according to claim 17, wherein the mechanical wave forms the response signal that is returned to the evaluation device. 19. The conductor having magnetostriction is a tubular sound wave conductor, which is provided coaxially with an electric detection conductor for transmitting the detection signal, and is mechanically connected to the discontinuous point by the transmitted detection signal. 18. The rodless linear drive of claim 17, wherein a wave is generated and the mechanical wave is returned to the evaluation device. 20. A conductor array provided on the seal band is accessible from the outside, and the second detection means includes conductor tap means in contact with the conductor, and the conductor tap means and the conductor 12. The rodless linear drive according to claim 11, wherein the contact points form the discontinuity. 21. The rodless linear drive device according to claim 20, wherein said conductor tap means electrically connects a plurality of conductors of said conductor row at said discontinuous points. 22. The rodless linear drive device according to claim 1, wherein the evaluation device is connected to only the first detection means or the second detection means. 23. The rodless linear drive device according to claim 1, wherein the first detection means is provided on the seal band, and the second detection means is provided on the drive unit. 24. The rodless linear drive device according to claim 1, wherein the evaluation device is connected only to the detection means on the housing side. 25. The rodless linear drive device according to claim 24, wherein the connection between the detection means on the housing side and the evaluation device is made adjacent to a point of attachment of the seal band to the housing. 26. The rodless linear drive according to claim 1, wherein the drive part is a piston.