CYLINDER, USE OF A CYLINDER

Description

[0001] The invention relates to a pneumatic or hydraulic cylinder according to the preamble of claim 1. The invention also relates to the use of a cylinder according to claim 5.

[0002] Pneumatic or hydraulic cylinders are used in a variety of applications, for example, in conveyor, drive, or handling technology, or in automation technology in general. Position detection is usually required to determine at least whether the cylinder piston is in the retracted or extended position. This piston position is then transmitted to a higher-level control unit.

[0003] In conventional cylinders, proximity switches or sensors are used to detect the position of the piston. These sensors are attached, for example, to a casing element of the cylinder housing. These position detection units are supplied with power via cables connected to external energy generator units or energy sources. The signal for transmitting the actual position of the piston is also transmitted via a cable to a control unit.

[0004] In this context, DE 10 2007 015 111 A1, for example, relates to a sensor device for a fluid power device, in particular a pneumatic cylinder. Furthermore, DE 10 2007 062 905 A1, for example, describes a magnetic cylinder sensor that serves to detect a piston position along a stroke of a piston of a working cylinder.

[0005] Furthermore, DE 203 00 594 U1, for example, discloses a cylinder with a linear drive. DE 10 2007 062 909 A1 relates to a magnetic or inductive sensor with an electronic evaluation unit for detecting a piston position along a stroke of a piston in a cylinder. Furthermore, CH 418 841 A relates, for example, to a working cylinder for pneumatic and hydraulic working media. Furthermore, JP H06 33911 A describes a piston position detection device capable of correctly detecting the piston position of a fluid pressure actuator without causing faulty operation.

[0006] The object of the invention is to provide a cylinder in which position detection can be realized with little effort.

[0007] Main features of the invention are defined in the characterizing part of claim 1. Embodiments are the subject of claims 2 to 5.

[0008] The object is achieved according to the invention in a hydraulic or pneumatic cylinder having a cylinder housing and a piston, wherein the piston is mounted in the cylinder housing so as to be movable between a retracted position and an extended position along a piston axis, and wherein at least one position detection unit is provided by means of which an actual position of the piston with respect to the piston axis can be determined, in that the at least one position detection unit has a transmitting unit for generating a signal for wirelessly transmitting the actual position to a control unit and an internal energy generator unit for supplying energy to the position detection unit. By dispensing with external cabling of the position detection unit, flexible positioning with low assembly effort is possible.

[0009] The piston axis is the central axis of the piston, along which the piston moves back and forth. The position detection unit determines the actual axial position of the piston, in particular, whether it has reached the retracted or extended position. The energy generator unit supplies the position detection unit and the transmitter unit partially or completely with electrical energy. The transmitter unit transmits the signal wirelessly to a higher-level control unit.

[0010] The energy generator unit is combined with the position detection unit and its transmitter unit as a single unit. The position detection unit can therefore be used independently without additional cabling.

[0011] Preferably, the energy generator unit converts the piston's kinetic energy into electrical energy to power the position detection unit. The use of other autonomous energy sources, such as light energy or temperature, is also conceivable.

[0012] According to the invention, the energy generator unit, together with the transmitter unit, is designed as a battery-free radio sensor module that operates in particular based on EcOcean technology. This technology generates sufficient electrical energy from a movement, for example, to transmit a radio signal. Known radio standards, such as Zigbee or Bluetooth, can be used for this purpose.

[0013] In an alternative embodiment, the energy generator unit is designed as a battery and / or a piezo element. A battery is easy to replace and requires relatively little space. A piezo element harnesses the energy from the piston movement and is therefore maintenance-free, as unlike a battery, it does not need to be replaced. In any case, the self-contained design of the position detection unit makes it independent of an external power supply. The system is accordingly robust.

[0014] According to the invention, the position detection unit comprises an actuating unit, by actuating which the signal can be generated, wherein the actuating unit can be mechanically switched between a rest position and a transmission position. The mechanical energy acting during switching can then be converted by the energy generator unit into electrical energy to supply the position detection unit with the transmission unit. The actuating unit can be moved from a transmission position to a rest position or from a rest position to a transmission position, wherein the actuating unit is preferably switched directly or indirectly by the piston. Thus, the signal generation is less susceptible to errors and operates reliably. It can also be advantageous if the actuating unit comprises an actuating switch, which is designed in particular as an actuating button. The signal can be generated by actuating the actuating switch, in particular the actuating button.The actuating unit is moved from the rest position to the transmit position or from the transmit position to the rest position.

[0015] Furthermore, according to the invention, the actuating unit comprises an actuating pin.

[0016] The actuating unit can be moved into the transmitting position and / or the rest position by moving the actuating pin. The movement of the piston causes the movement of the actuating pin.

[0017] The actuating switch, in particular the actuating button, can be actuated by the movement of the actuating pin. In a preferred embodiment, the actuating pin rests against the actuating switch, in particular the actuating button.

[0018] The actuating pin is preferably movably mounted within the cylinder housing. For example, upon reaching the retracted or extended position, an actuation unit is triggered by contact between the piston and the actuating pin, which is then moved. The pin enables effective mechanical signal generation.

[0019] In an actuating unit with an actuating magnet not according to the invention, the magnet functions contactlessly, i.e., without contact with the piston. This eliminates the need for an opening in the cylinder that would otherwise have to be sealed, unlike with an actuating pin. Furthermore, detecting intermediate piston positions using an actuating magnet is easier.

[0020] Preferably, the position detection unit has a reset unit for returning the actuating unit to the rest position or the transmit position. The reset unit is designed, for example, as a spring. This makes the design quite simple. If necessary, the reset can generate an additional signal.

[0021] Advantageously, a trigger unit is provided for actuating the actuating unit.

[0022] The trigger unit allows the actuating unit to be moved from a rest position to a transmit position or from a transmit position to a rest position. The trigger unit is firmly connected to the piston and moves accordingly.

[0023] In an actuating unit with an actuating pin, the triggering unit is designed, for example, as a raised area or contact surface in the front areas of the piston.

[0024] In an actuating unit with an actuating magnet not according to the invention, it may be advantageous if the triggering unit is designed at least as a triggering magnet or as a magnetizable element.

[0025] The at least one trigger magnet is provided on the piston. The piston comprises a piston head and a piston rod, and the trigger magnet is provided on the piston head. The piston head has a base and a peripheral surface, with the trigger magnet being provided on the base and / or the peripheral surface. The magnet functions reliably as a trigger unit and requires no power connection.

[0026] The trigger magnet is, for example, a magnetic strip. The magnetic strip can be straight, circular, or shaped like a segment of a circle. In an advantageous embodiment, the magnetic strip runs circumferentially around the piston axis. Due to the attraction and / or repulsion between the actuating magnet and the trigger magnet, the actuating unit can be brought into the transmitting position and / or the rest position.

[0027] It is also advantageous if at least two position detection units are provided. The position detection units are axially spaced apart so that two different axial actual positions are measured. For example, exactly two position detection units are provided, with one positioning unit located at each end of the cylinder. This allows the retracted position and the extended position, i.e., the two end positions, to be reliably detected.

[0028] It can be advantageous if the cylinder housing has a cover element, a base element, and a casing element. The cover element comprises, in particular, a bearing for the piston, in particular for a piston rod. The base element is arranged opposite the cover element in a direction axial to the piston axis. The cover element and the base element close end faces of the cylindrical casing element, which is accordingly arranged between the cover element and the base element. The at least one position detection unit is then arranged in the base element and / or cover element and / or casing element.

[0029] Preferably, one position detection unit is arranged in the cover element and / or one position detection unit is arranged in the base element. Two position detection units are arranged in the casing element. The two position detection units are arranged axially one above the other. This arrangement improves the accuracy of position detection.

[0030] According to the invention, the cylinder housing has at least one cavity, wherein the at least one position detection unit is provided entirely within the at least one cavity. A separate cavity is preferably provided in the cylinder housing for each position detection unit. By being arranged in a cavity, the position detection unit is protected from dirt or damage.

[0031] The above-mentioned task is also achieved by using a cylinder as described, whereby the position detection unit is used to determine the actual position of a cylinder. When used accordingly, the user benefits from the aforementioned advantages.

[0032] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. They show: Fig. 1 shows a cylinder not according to the invention with an actuating pin and position detection units in the cover and base elements; Fig. 2 shows a cylinder not according to the invention with an actuating magnet and position detection units in the cover and base elements; Fig. 3 shows a cylinder not according to the invention with an actuating magnet and position detection units in the casing element; Fig. 4a shows a cylinder not according to the invention with an extended piston; Fig. 4b shows a cylinder not according to the invention with a retracted piston.

[0033] According to Fig. 1 a cylinder 1 has a cylinder housing 10 with a cover element 11, a jacket element 14 and a base element 13. The cover element 11 has a bearing 12 for a piston 20 with a piston axis 30 that extends along a central axis of the piston 20. The base element 13 is arranged opposite the cover element 11 in a direction axial to the piston axis 30. The jacket element 14 is arranged between the cover element 11 and the base element 13. The piston 20 has a piston rod 23 and a piston head 22. The piston rod 23 is movably mounted in the bearing 12. The piston head 22 is movably mounted in the jacket element 14.

[0034] The cylinder housing 10 has two separate cavities 15. One cavity 15 is provided in the cover element 11 and one cavity 15 is provided in the base element 13. The cavities 15 can each be closed by a cover 16. A position detection unit 40 is provided in each of the cavities 15.

[0035] The position detection unit 40 has a transmitter unit 41 and an internal energy generator unit 42. The transmitter unit 41 serves to generate a radio signal for wirelessly transmitting the actual axial position of the piston relative to the piston axis 30 to a control unit 100. The internal energy generator unit 42 supplies the position detection unit 40 with energy, i.e., current. In particular, the so-called EnOcean technology is used here. An actuation unit 43 comprising an actuation switch 44 and an actuation pin 45 is also provided. Furthermore, a reset unit 48 designed as a spring is provided.

[0036] According to Fig. 2 The actuating pin 45 of the position detection unit 40 is replaced by an actuating magnet 46, which is designed as a disc magnet. In addition, a trigger unit 50 designed as a trigger magnet is provided in the base 24 of the piston head 22. The trigger magnet is a circular magnetic strip that runs circumferentially around the piston axis 30. Otherwise, the cylinder 1 is structurally identical to the cylinder according to Fig. 1 .

[0037] After Fig. 3 An actuating magnet 46 is also provided in each case. The two position detection units 40 are positioned axially spaced apart in a cavity 15 of the casing element 14. The trigger unit 50 is arranged in a casing surface 25. It is again designed as a trigger magnet, wherein the trigger magnet is a circular magnetic strip. The cavity 15 is closed by the cover element 11 and the base element 13. Apart from these features, the cylinder 1 according to Fig. 3 identical to the cylinder according to Fig. 1 .

[0038] The piston 20 is in the cylinder housing 10 between an extended position P2 according to Fig. 4a and a retracted position P1 after Fig. 4bmovably mounted. An actuating pin 45 is movably mounted in the base element 13. In the extended position P2, the actuating pin 45 is partially arranged in the casing element 14 due to the action of the reset unit 48. The actuating switch 44 rests against the actuating pin 45. Thus, the actuating unit 43 or the actuating switch 44 is in a rest position RL.

[0039] When the piston 20 moves into the retracted position P1, the actuating pin 45 is moved out of the casing element 14 by means of the piston 20. This also moves the actuating switch 44. The actuating unit 43 is then in a transmission position SL, as shown, and transmits a radio signal to the control unit 100.

[0040] If an actuating magnet 46 and a triggering unit 50 designed as a trigger magnet are provided instead of the actuating pin 45, the actuating unit 43 can be brought into the transmission position SL due to the magnetic repulsion between the actuating magnet 46 and the trigger magnet.

[0041] All features and advantages arising from the claims, the description and the drawings, including structural details, spatial arrangements and method steps, can be essential to the invention both individually and in a wide variety of combinations.

Claims

1. Cylinder (1) having - a cylinder housing (10) and a piston (20), wherein the piston (20) is mounted in the cylinder housing (10) so as to be movable along a piston axis (30) between a retracted position (P1) and an extended position (P2), - wherein provision is made of at least one position-identification unit (40) by means of which an actual position of the piston (20) in relation to the piston axis (30) is able to be determined, - wherein the at least one position-identification unit (40) has a transmitting unit (41) for generating a signal for wireless communication of the actual position to a control unit (100), and the at least one position-identification unit (40) has an internal energy-transducer unit (42) for supply of energy to the position-identification unit (40), wherein the cylinder housing (10) has at least one cavity (15), wherein the at least one position-identification unit (40) is provided completely within the at least one cavity (15), wherein the energy-transducer unit (42) is designed together with the transmitting unit (41) as a battery-free radio-sensor module, wherein the position-identification unit (40) comprises an actuating unit (43) by way of the actuation of which the signal is able to be generated, characterized in that the actuating unit (43) is able to be switched mechanically between a rest position (RL) and a transmitting position (SL), wherein the actuating unit (43) comprises an actuating pin (45).

2. Cylinder (1) according to Claim 1, characterized in that the actuating unit (43) comprises an actuating switch (44).

3. Cylinder (1) according to Claim 1 or 2, characterized in that the position-identification unit (40) has a return unit (48) for the return movement of the actuating unit (43) into the rest position (RL) or the transmitting position (SL).

4. Cylinder (1) according to one of the preceding claims, characterized in that provision is made of at least two position-identification units (40).

5. Use of a cylinder (1) according to one of the preceding claims, wherein the position-identification unit (40) is used for determining the actual position of the piston (20).