DE102007057810A1 - Position measuring device for a fluidic cylinder comprises a longitudinal channel in a cylinder housing for receiving a sensor support which lies on a housing end region and is supported on a pressure spring - Google Patents

Abstract

Fluidic cylinder comprises a longitudinal channel in a cylinder housing for receiving a sensor support (20) which lies on a housing end region, can be adjusted using an adjusting screw (32) and is supported on a pressure spring (29) on the opposing housing end region. Preferred Features: The cylinder housing (10) comprises a cylinder tube (11) closed by cylinder lids (12, 13). The adjusting screw is positioned on or in the lid (13) or supported on this lid. The pressure spring is fixed on the sensor support.

Description

The The invention relates to a fluidic cylinder with position detection device for the piston position according to the genus of claim 1.

A fluidic cylinder with such a position detection device is, for example, from DE 4306539 C2 known. Several sensors are fixed to a support rod and can be inserted with this in a longitudinally extending receiving bore and fixed therein. One problem with such an arrangement is the adjustment of the sensors or of the carrier rod relative to the desired measuring positions. The support rod and the sensors arranged thereon must therefore be manufactured with high accuracy. This is on the one hand complicated and expensive and allows a later correction of the measurement positions only with great effort.

A Object of the present invention is an arrangement to provide according to the type mentioned, the low manufacturing accuracy nevertheless a high switching accuracy and easy readjustment allows.

These The object is achieved by a fluidic Cylinder with position detection device for the piston position solved with the features of claim 1.

Of the Advantage of the position measurement according to the invention is in particular that in a simple way by the adjusting screw an adjustment or readjustment of the measuring positions done can, without any assembly work would be required. Even with low precision manufactured sensor carrier can be done quickly and easily a very precise adjustment. Also possible additional influences, such as temperature changes or mechanical changes, can be fast and easily compensated. The mounting of the sensor carrier and thus the sensors are also fast and with low Effort.

By the measures listed in the dependent claims are advantageous developments and improvements in the claim 1 indicated arrangement possible.

at from a closed by two cylinder cover cylinder tube existing cylinder housing, the adjusting screw is preferred arranged on the first cylinder cover and the compression spring on or in second housing cover positioned or supports on this second housing cover.

In a preferred embodiment, the compression spring on the sensor carrier fixed and engages in particular in the second housing cover such that a lid portion engages behind in the axial direction becomes. As a result, the sensor carrier with the help of the second Housing cover inserted in the longitudinal channel and be pulled out of this again.

In A preferred embodiment is the sensor carrier designed as a board and is particularly in longitudinal grooves held the longitudinal channel, wherein the longitudinal grooves not just the sensor carrier in a designated fixed Keep position, but this position can also be angular be adjusted so that the sensors in the radial direction to the longitudinal axis of the piston and thus aligned directly to the permanent magnet out are.

At least Two magnetic field-sensitive sensors are for detecting the two End positions of the piston positioned accordingly, optionally also additional intermediate positions by further Sensors are detectable.

In Advantageously, a microprocessor or microcontroller (CPU) arranged on the sensor carrier and with the sensors connected. The CPU has in this case advantageously means for Sensor signal measurement and conditioning and / or means for implementation a learning mode (teach mode). This forms the sensor carrier a self-sufficient position detection device, which is used to form the Position signals and / or to carry out the learning mode no additional electronic resources needed. Farther can still have a voltage supply device on the sensor carrier and additional separate electronic components arranged be that perform desired functions beside the CPU, such as B. signal conditioning functions.

Of the Learning mode is preferred as a learning mode for the sensor signals assigned switching points formed. As part of the learning mode can while the switching thresholds are varied so that a fine adjustment the switching positions in the range of a few millimeters to simple Way is possible.

Voltage and signal lines are routed to the outside of the CPU. For easy and quick implementation of the learning mode, these are connectable to a manually operable learning device, which preferably has a switch device and optical display means. In a preferred embodiment, the switch unit has switches for switching the power supply on and off and switches for impressing signal levels on the signal lines. By predetermined switch operations and in response to the feedback from the CPU visualized by the visual display means, the learning mode can be done quickly and easily.

The Magnetic field sensitive sensors are expediently designed as Hall elements, in principle, other designs Magnetic field-sensitive sensors are possible.

One Embodiment of the invention is in the drawing shown and in the following description in more detail explained. Show it:

1 a fluidic cylinder in longitudinal section with inserted sensor carrier,

2 an end view of the cylinder housing with removed cylinder cover and inserted sensor carrier,

3 the diagram of a connected to the CPU on the sensor carrier manually operable learning device and

4 a sensor waveform for explaining the operation.

That in the 1 and 2 illustrated fluidic cylinder housing 10 consists in a conventional manner of a cylinder tube 11 , which at its two opposite end sides by cylinder cover 12 . 13 is closed. In the cylinder tube 11 is one with a permanent magnet 14 provided piston 15 slidably guided, whose piston rod 16 through the one cylinder cover 12 passed through, wherein in the case of a double-acting cylinder, a sealing implementation is required. The piston 15 divides the interior of the cylinder housing 10 in two cylinder chambers 17 . 18 on. Their fluidic supply lines and leads are not shown for simplicity.

In such a cylinder housing 10 it can also be a rodless cylinder, in which case the piston 15 with one on the cylinder housing 10 guided carriage is mechanically or magnetically connected.

The cylinder tube 11 has a lengthwise continuous longitudinal channel 19 for receiving a designed as an elongated circuit board sensor carrier 20 , The longitudinal channel 19 has grooves at two opposite points 21 on, in which the sensor carrier 20 is guided to a defined Po sition in the longitudinal channel 19 take. In the laterally offset to the middle longitudinal channel 19 are the grooves 21 arranged so that its to the cylinder chambers 17 . 18 facing surface is arranged perpendicular to a radial line.

In 2 are still more channels and holes 22 exemplified and shown schematically. Such may be screw holes for attaching the cylinder cover 12 respectively 13 or act to fluidic channels.

The designed as an elongated board sensor carrier 20 carries on its in the inserted state to the piston 15 pointing side three magnetic field sensitive sensors 23 - 25 , which are formed for example as Hall elements or Hall sensors. The two outer sensors 23 and 25 serve to detect the end position of the piston 15 , At the opposite flat side of the sensor carrier 20 is in the range of the sensor 25 , So at an end, a microprocessor or microcontroller as a CPU 26 arranged. This is in a manner not shown, for example via interconnects, with the sensors 23 - 25 connected and receives their sensor signals. One on the CPU 26 connected connection cable 27 is from the cylinder housing 10 led out to the outside. The connection may be a fixed connection, for example a solder connection, or a plug connection 28 act.

The sensor carrier 20 is at his the cylinder cover 13 facing end region with a compression spring 29 provided, which is curved substantially S-shaped, in a cavity 30 of the cylinder cover 13 engages and there with respect to the longitudinal direction a projection 31 engages behind. This pressure spring 29 pushes the sensor carrier 20 resilient against an adjusting screw 32 in a threaded hole of the other cylinder cover 12 in the longitudinal direction of the sensor carrier 20 is arranged adjustable. With the help of this adjusting screw 32 can be the sensor carrier 20 and thus the sensors arranged thereon 23 - 25 adjust or position in the longitudinal direction, of course, the positions using this adjustment screw 32 can be subsequently set or readjusted.

By grasping the projection behind 31 through the compression spring 29 can the sensor carrier 20 with the help of the cylinder cover 13 in the longitudinal channel 19 inserted and pulled out of this again. For this purpose, the pressure spring before insertion 29 in the cavity 30 so introduced that the lead 31 is engaged behind.

In an alternative embodiment, the cavity 30 also omitted, and a simpler design spring 29 only supports against the wall of the cylinder cover 13 from.

The CPU 26 has a teach mode program to indicate the respective positions of the piston 15 to set or train exactly in the area of the sensors. To operate the learning process is a manually operable learning device 33 or a semi-automatic device, eg. B. a PLC-controlled switching device connected to the connecting cable 27 by means of an electrical connector device 34 is connectable. The connection cable 27 otherwise it is directly connected to an electrical connection cable 35 connected, which is connected to an external power supply device and / or control device. To perform the learning process, the connection between the connection cable 27 and the electrical connection cable 35 solved, and the learning facility 33 is pinned between. The electrical connection cable 35 is then in turn via a connector device 36 with the learning facility 33 connected.

The learning facility 33 has a switch arrangement 37 , being a double switch 38 in two power supply lines 39 is switched to the supply voltage Uv of the CPU 26 to supply or interrupt. Two more switches 40 . 41 are used to interrupt two signal lines 42 . 43 about which in the cpu 26 prepared sensor signals in normal operation of an external control device leads supplied. These two signal lines 42 . 43 are in the learning facility 33 over two signal lights 44 . 45 , which may be, for example, LED, with a connecting line 46 to the CPU 26 connected.

The mode of operation of the position detection device will be described below with reference to FIG 4 be explained. The sensors designed as Hall elements 23 - 25 detect when passing in the piston 15 arranged permanent magnets 14 each the radial magnetic field, so that in 4 shown field profile H results. By varying the respective switching threshold in the CPU 26 is set, the respectively detected position can be varied by about 2 mm, depending on the amount of the switching threshold. As a result, for example, the stroke tolerance of the detected magnetic field H can be compensated.

In the following, the setting of the switching thresholds in the learning mode will be explained by way of example. Pre-positioning can be achieved by adjusting or adjusting the adjusting screw 32 respectively. Due to the pre-adjustment and the adjustment of the switching thresholds in the learning mode, a very high switching accuracy can be achieved overall, both in the respectively defined temperature range and across all components and production batches.

The following exemplary learning refers to the two end positions of the piston 15 passing through the two sensors 23 . 25 should be signaled. The teaching of intermediate positions, for example a center position, by the sensor 24 can be done in a similar manner.

First, the piston 15 placed in a middle position. Then by appropriate switch positions of the switch 40 . 41 Signal level H (high) on the two signal lines 42 . 43 placed on the switching outputs of the CPU 26 , Then by turning the double switch 38 the voltage supply with supply voltage Uv to the CPU 26 created. Then, by flipping the switch 40 . 41 Switching level L (Low) on the signal lines 42 . 43 placed. This switching sequence signals the CPU 26 that the tutorial should be started. Of course, this can also be effected by other switching sequences.

The CPU 26 then signals the beginning of the tutorial by clock signals on the signal lines 42 . 43 that is a flashing of the signal lights 44 . 45 cause.

Now the piston 15 in the left end position on the cylinder cover 13 brought to teach this position. The power supply is by means of the double switch 38 then off, and the signal line 42 , which corresponds to the switching output of this piston position, with the signal level H and the signal line 43 subjected to the signal level L. Then the power supply is switched on again. The left end position of the piston 15 has been taught in, and the left signal lamp flashes as confirmation of success 44 ,

Now the piston 15 in the opposite end position on the cylinder cover 12 brought, and the power supply is turned off. The signal line 42 is connected to the signal level L and the signal line 43 subjected to the signal level H. Then the power supply is switched on again. The right-hand end position has been taught in, and the right signal lamp flashes as a confirmation of success 45 , Switching off and then switching back on completes the learning mode.

Of course, the learning mode can also be effected by other signal actuations and other switching sequences of the supply voltage. It is essential that a simple learning device 33 can be used, which has only simple switches and signal lights, such as LED.

The learning mode can be supplemented by other functions. For example, this can be terminated automatically when the intended sequence of operation of the switch assembly 37 is not adhered to. If an error is detected during the learning process, such an error may occur fast change-flashing of the two signal lights 44 . 45 are displayed. Such possible errors are, for example, that the magnet 14 outside the described tolerance range of the sensors 23 . 25 that is a faulty sensor or a misplaced piston 15 is present that there is a wrong voltage polarity or the like.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4306539 C2 [0002]

Claims (12)

Fluidic cylinder with position detection device for the piston position, with a cylinder housing in which a piston provided with a permanent magnet is displaceably guided, and with a longitudinal channel in the cylinder housing for receiving an at least two magnetic field-sensitive sensors having elongate sensor carrier, characterized in that the sensor carrier ( 20 ) at a housing end area on an adjusting screw ( 32 ) abuts the axial adjustment and at the opposite housing end to a compression spring ( 29 ) is supported. Cylinder according to claim 1, characterized in that the cylinder housing ( 10 ) from a through two cylinder cover ( 12 . 13 ) closed cylinder tube ( 11 ), that the adjustment screw ( 32 ) is arranged on the first cylinder cover and the compression spring ( 29 ) on or in the second housing cover ( 13 ) or on this second housing cover ( 13 ) is supported. Cylinder according to claim 2, characterized in that the compression spring ( 29 ) on the sensor carrier ( 20 ) is fixed and in particular in the second housing cover ( 13 ) engages such that a cover area ( 31 ) is engaged behind in the axial direction. Cylinder according to one of the preceding claims, characterized in that the sensor carrier ( 20 ) is designed as a circuit board and in particular in longitudinal grooves ( 21 ) of the longitudinal channel ( 19 ) is held. Cylinder according to one of the preceding claims, characterized in that two magnetic field-sensitive sensors ( 23 . 25 ) for detecting the two end positions of the piston ( 15 ) are positioned. Cylinder according to one of the preceding claims, characterized in that designed as a microprocessor or microcontroller CPU ( 26 ) on the sensor carrier ( 20 ) and with the sensors ( 23 - 25 ) connected is Cylinder according to claim 6, characterized in that the CPU ( 26 ) Means for sensor signal measurement and conditioning and / or means for performing a learning mode (teach mode). Cylinder according to claim 7, characterized that the learning mode as a learning mode for the sensor signals assigned switching points is formed. Cylinder according to one of claims 6 to 8, characterized in that from the CPU ( 16 ) from voltage and signal lines ( 39 . 42 . 43 ) led to the outside and with a manually operable learning device ( 33 ) are connectable. Cylinder according to claim 9, characterized in that the learning device ( 33 ) a switch device ( 37 ) and optical display means and / or acoustic display means ( 44 . 45 ) owns. Cylinder according to claim 10, characterized in that the switch device ( 37 ) Switch ( 38 ) for switching on and off the power supply and switches ( 40 . 41 ) for impressing signal levels on the signal lines ( 42 . 43 ) owns. Cylinder according to one of the preceding claims, characterized in that the magnetic field-sensitive sensors ( 23 - 25 ) are formed as Hall elements.