Pneumatic motor with rotary position measuring and method for measuring rotational speed

Abstract

The invention relates to a pressurised gas operated drive device (10) with rotation state measurement and to a method for rotation state measurement. The drive device comprises a compressed gas motor (14) with a stator (20), a rotor (24) rotating relative to the stator under the influence of compressed air about an axis of rotation (22), the rotor having lamellar slots (64.1, 64.2, 64.3, 64.4, 64.5) extending in the longitudinal direction of the axis of rotation (22) and a rotor shaft (26) defining the axis of rotation (22), which is rotatably mounted on the stator (20) via bearing shields (32, 34), and a sensor device (56) with a sensor element (58) for determining a state of rotation or a rotational speed of the rotor (24) relative to the stator (20), wherein the sensor element (58) is aligned with a mark (61) coupled to the rotor (24) for determining the state of rotation or the rotational speed of the rotor (24).To enable a compact design of the drive unit, it is provided that the marking (61) are the lamellar slots (64.1, 64.2, 64.3, 64.4, 64.5).

Description

[0001] The invention relates to a compressed gas-operated drive device comprising a compressed gas motor with a stator, a rotor rotating about an axis of rotation relative to the stator under the influence of compressed air, the rotor having lamellar slots extending in the longitudinal direction of the axis of rotation and a rotor shaft defining the axis of rotation, which is rotatably mounted on the stator via bearing shields, and a sensor device with a sensor element for determining a state of rotation or a rotational speed of the rotor relative to the stator, wherein the sensor element for determining the state of rotation or the rotational speed of the rotor is aligned with a mark coupled to the rotor.

[0002] A compressed gas-operated drive device of the type mentioned above is known from DE 20 2016 104 704 U1 (= DE 10 2016 115 930 A1). The compressed gas-operated drive device comprises a compressed gas motor with a stator and a rotor rotating about an axis of rotation relative to the stator under the influence of compressed gas. The rotor has a rotor shaft defining the axis of rotation, which is rotatably mounted on the stator via bearing shields. The stator and the bearing shields define a working space in which the rotor rotates. The drive device further comprises a sensor device for determining the rotational state of the rotor relative to the stator.

[0003] The sensor device is designed to determine the rotational speed of the rotor relative to the stator, wherein the sensor device has a sensor element which is directed towards a section of the shaft lying outside the working space, on which a mark is attached.

[0004] The design includes a radial bore in the housing of the compressed gas motor, in which the sensor element of the sensor device is positioned so that the marking on the section of the shaft located outside the working area can be detected. The markings are formed by two recesses in this section of the shaft.

[0005] According to the state of the art, the sensor element protrudes radially beyond a substantially cylindrical housing wall of the compressed air motor, so that the radially protruding sensor element prevents space-saving installation of the compressed air motor in, for example, a hollow cylindrical receptacle of a device, spindle or vise.

[0006] DE 10 2013 020 985 A1 relates to an electric machine, in particular for a motor vehicle. The electric machine comprises a housing with a rotor shaft arranged at least partially within the housing, which is rotatable about an axis of rotation relative to the housing. Furthermore, a rotor part is provided that is non-rotatably connected to the rotor shaft, and a corresponding stator part is provided that is fixed at least indirectly to the housing. The stator part includes a sensor device for detecting at least one measured quantity that characterizes a rotation of the rotor shaft relative to the housing. The sensor device is designed as a speed and / or angle sensor and comprises a stator part that is fixed at least indirectly to the housing. The sensor device also comprises a rotor part corresponding to the stator part, which is non-rotatably connected to the rotor shaft.

[0007] DE 10 2015 219 502 A1 relates to a drive device for providing linear motion, comprising a drive housing in which an electric rotary drive is housed. The drive drive includes a stator in which a rotor is rotatably arranged about an axis of rotation relative to the stator. The rotor has a recess with an internal thread and a piston rod extending along the rotor's axis of rotation. The piston rod is movably mounted in the rotor by means of a threaded section adapted to the internal thread. A sensor device for determining the position of the piston rod relative to the drive housing is associated with the connecting rod and / or the rotor. The sensor device is optionally designed as a switching device or as a proportional sensor.

[0008] DE 10 2016 226 293 A1 relates to a brushless electric machine. The machine comprises a housing with at least one rotor rotatably mounted on a shaft within the housing and a stator, the rotor being associated with a non-contact rotor position detection device. The rotor position detection device has a multipole magnetic ring fixed to the shaft and at least one magnetic field-sensitive sensor radially associated with the outer circumference of the magnetic ring.

[0009] DE 10 2019 122 046 A1 relates to a device for measuring the angular position of a shaft. The device comprises a first housing part and a shaft arranged in the first housing part and rotatable about an axis of rotation. The device further comprises a magnetic unit with at least one permanent magnet attached to the shaft, a second housing part with a projection extending along the axis of rotation, and a magnetic field sensor element arranged inside the projection of the second housing part.

[0010] German patent DE 10 2019 118 139 A1 discloses a rotary vane rotor, which is intended in particular for rotary vane vacuum pumps or rotary vane compressors. To monitor the wear of vanes that can be moved in slots, a sensor is assigned to the slots to detect the position of the vanes in the slots.

[0011] From DE 10 2004 027 386 A1 a flow rate sensor is known which has a sensor arranged in a cover of a housing, by means of which the movement of teeth of a measuring element is detected.

[0012] The present invention is based on the objective of further developing a compressed gas-operated drive device of the type mentioned above in such a way that simple and space-saving mounting of the compressed gas motor is enabled. In particular, it should be possible to mount the compressed gas-operated drive device directly in a hollow cylindrical receptacle, even without a housing.

[0013] The problem is solved by the features of the invention according to independent claim 1 or independent claim 5.

[0014] The embodiment according to the invention is characterized in that the marking is the lamellar slots which extend into an end face of the rotor, wherein the end face is directed towards one of the bearing shields and wherein the sensor element is arranged in one of the bearing shields and is aligned with the lamellar slots.

[0015] The marking is thus detected within the work area, enabling a compact design. Furthermore, the existing lamellar slots in the rotor are used, eliminating the need to create new markings.

[0016] Compared to the prior art, the advantage is that the sensor element does not protrude radially beyond a cylindrical surface of the housing of the compressed gas-operated drive unit. This allows the compressed gas-operated drive unit to be mounted in a cylindrical housing.

[0017] In a particularly preferred embodiment, the bearing shield is provided with a receptacle extending axially parallel to the axis of rotation, in which the sensor element of the sensor device is arranged. This enables a particularly compact design.

[0018] The mounting can be designed as an axial bore. Alternatively, the bore can be a threaded bore into which the sensor element is screwed.

[0019] The sensor element can be designed as a non-contact sensor such as an inductive, capacitive, optical and / or magnetic sensor.

[0020] A particularly compact design is characterized by the fact that the sensor element is arranged in a rear bearing shield, i.e., one facing away from the drive side.

[0021] According to an inventive embodiment, a compressed gas-operated drive device is known from the prior art and is not within the scope of the present claims, comprising a compressed gas motor with a stator, a rotor rotating about an axis of rotation relative to the stator under the influence of compressed air, the rotor shaft defining the axis of rotation and rotatably mounted on the stator via bearing shields, and a sensor device with a sensor element for determining a state of rotation or a rotational speed of the rotor relative to the stator, wherein the sensor element for determining the state of rotation or the rotational speed of the rotor is aligned with a marking coupled to the rotor.It is provided that the marking is formed on an end face of a body extending radially from the rotor shaft, wherein the end face of the body faces one of the bearing shields and wherein the sensor element is arranged in one of the bearing shields and aligned with the marking.

[0022] According to a particularly preferred embodiment, the body is the rotor and the end face with the marking is also an end face of the rotor. This also enables a particularly compact and robust design.

[0023] The body can also be a disk or part of a disk that runs parallel to the end face of the rotor and is penetrated centrally by the rotor shaft. The body can be located within a working area of ​​the rotor or outside the working area at an end of the rotor shaft that penetrates the bearing shield.

[0024] Further details, advantages and features of the invention will become apparent not only from the claims, but also from the following description of a preferred embodiment.

[0025] They show: Fig. 1 a sectional view of a compressed gas-operated drive device, Fig. 2 a perspective view of a rotor, Fig. 3a a perspective view of the compressed gas motor without housing, Fig. 3b an exploded view of the compressed gas motor and Fig. 4 a sectional view of a gear unit that can be flanged to a compressed air motor.

[0026] Fig. 1 Figure 1 shows a sectional view of a compressed gas-operated drive device 10 with a compressed gas motor 12, which is arranged in a housing 14. The housing 14 comprises a sleeve 16, which is closed at each end by a housing cover 17, 18.

[0027] The compressed gas motor 12 comprises a stator 20 and a rotor 24, which rotates about an axis of rotation 22 relative to the stator under the influence of compressed gas. The rotor shaft 26 defines the axis of rotation 22. The rotor shaft 26 is rotatably mounted on the stator 20 via bearing elements 28, 30 in front and rear bearing shields 32, 34, respectively.

[0028] The stator 20 comprises a cylinder 36 inserted into the sleeve 16, which encloses a drive chamber 38. The drive chamber 38 can be pressurized with compressed gas via a supply channel 40, the supply channel 40 running through the housing cover 18 and the bearing shield 32 and opening into the drive chamber 38. The exhaust air is discharged via an exhaust duct 42.

[0029] A front section 44 of the rotor shaft 26 is coupled to a gear stage 46. The gear stage 46 comprises a drive shaft 48, which is rotatably mounted in the housing 14 via bearing elements 50, 52 and is coupled to the section 44 of the rotor shaft 26 via a planetary gear 54.

[0030] According to the invention, the pressurised gas-operated drive device 10 has a sensor device 56 to determine the rotational speed of the rotor 24 relative to the stator 20.

[0031] According to the invention, the sensor device 54 comprises a sensor element 58 which is arranged and aligned in the rear bearing shield 32 in such a way as to scan a marking 61 formed on an end face 60 of the rotor 24. The sensor element 58 is received in an axial bore 62 which runs parallel or substantially parallel to the axis of rotation 22 and is formed in the bearing shield 32.

[0032] Fig. 2 shows the rotor 24 with rotor shaft 26 in a perspective view.

[0033] In the rotor 24, lamellar slots 64.1, 64.2, 64.3, 64.4, 64.5 are formed in the longitudinal direction, preferably evenly distributed in the circumferential direction, which extend at least to the rear end face 60 of the rotor 24 and form the marking 61.

[0034] The sensor element 58 is designed as a non-contact sensor, such as an inductive sensor. When the rotor 24 rotates, the sensor element 58 detects the lamellar slots 64.1, 64.2, 64.3, 64.4, 64.5 opening in the end face 60, which are then identified as the marking 61. During rotation, the sensor element 58 detects a change in material between the metallic end face 60 and the non-metallic lamellar slot, generating a pulse each time. This pulse can be evaluated by a processing unit to determine the rotational speed or rotational movement of the rotor. In the illustrated embodiment, five pulses are generated per revolution.

[0035] By arranging the sensor element 58 in the bearing shield 32 and parallel or substantially parallel to the axis of rotation 22, a particularly compact design is achieved. Compared to the prior art, the advantage is that the sensor device 56 does not project radially beyond the cylindrical housing 14.

[0036] Consequently, due to its cylindrical surface, the compressed air motor can be accommodated or integrated in a space-saving manner in a hollow cylindrical receptacle, even without housing 14.

[0037] Fig. 3a Figure 1 shows the inventive compressed gas motor 12 in the form of a self-designed, built-in motor without a housing 14, which can be installed directly in a space-saving manner in a cylindrical receptacle, e.g., a device, spindle, or vise. Herein lies the particular advantage of the present invention, wherein the sensor device 56 is arranged in the axial bore 62 of the bearing shield 32, thus enabling the space-saving installation even without a housing 14. The bearing shields 32, 34 are connected to the end face of the stator 20 and form a compact unit that can be installed even without a housing 14.

[0038] Fig. 3b Figure 1 shows an exploded view of the compressed gas engine 12. The lamellar slots 64.1, 64.2, 64.3, 64.4, 64.5 are designed to receive corresponding lamellar slots 65.1, 65.2, 65.3, 65.4, 65.5. The lamellar slots 65.1, 65.2, 65.3, 65.4, 65.5 are inserted into the lamellar slots 64.1, 64.2, 64.3, 64.4, 64.5 so that they are movable in the radial direction when the rotor rotates and, during operation of the engine, bear against an inner surface of the cylinder 36, thereby forming flow channels for driving the rotor 24.

[0039] Fig. 4Figure 1 shows a sectional view of a gear stage 66 coupled to a rotor shaft 68 of a compressed air motor 70. The gear stage 66 comprises a planetary gear 72, which is positively coupled to one end of the rotor shaft 68. A drive shaft 74 is driven via the planetary gear 72. The drive shaft 74 is rotatably mounted in a housing 76 of the gear stage 66 via a bearing element 75. The housing 76 is covered at its end face by a housing cover 78. A radially extending receptacle 80, such as a bore, is formed in the housing cover 78, in which a sensor device 82 is received, which is not within the scope of protection of the present invention.

[0040] The sensor device 82 comprises a sensor element 84, which interacts with a sensor nut 86 arranged on the drive shaft 74. The sensor nut 84 has various magnetizations around its circumference, which are detected by the sensor element 84 without contact in order to measure the rotational speed of the drive shaft 74.

[0041] By arranging the sensor device 82 in the gear stage, it is made possible for the housing of the flanged pneumatic motor 70 to retain its cylindrical shape, which is advantageous for many applications in order to enable an optimal installation position for the pneumatic motor 70.

Claims

1. A compressed gas-operated drive unit (10), comprising a gas motor (12) with a stator (20); with a rotor (24) rotating relative thereto about a rotary axis (22) when compressed air is applied to it, and having lamella slots (64.1, 64.2, 64.3, 64.4, 64.5) extending in the longitudinal direction of the rotary axis (22) and a rotor shaft (26) defining the rotary axis (22) and rotatably mounted on the stator (20) using end shields (32, 34); and with a sensor unit (56) with sensor element (58) for determining a speed of the rotor (24) relative to the stator (20), wherein the sensor element (58) is aligned with a marking (61) coupled to the rotor (24) for determining the speed of the rotor (24), characterized in that the marking (61) is provided by the lamella slots (64.1, 64.2, 64.3, 64.4, 64.5) which extend into an end face (60) of the rotor (24), wherein the end face (60) faces one of the end shields (32, 34) and wherein the sensor element (58) is arranged in one of the end shields (32, 34) and aligned with the lamella slots (64.1, 64.2, 64.3, 64.4, 64.5).

2. The compressed gas-operated drive unit according to claim 1, characterized in that a receptacle (62), inside which the sensor element (58) is arranged and which extends in the axial direction parallel to the rotary axis (22), is formed in the end shield (32, 34), wherein the receptacle (62) is preferably designed as an axial hole.

3. The compressed gas-operated drive unit according to claim 2, characterized in that the axial hole (62) is designed as a threaded hole into which the sensor unit (56) with sensor element (58) is screwed.

4. The compressed gas-operated drive unit according to at least one of the preceding claims, characterized in that the sensor element (58) is designed as a contactless sensor, in particular as an inductive, capacitive, optical and / or magnetic sensor.

5. A method for determining a speed of a rotor (24) of a compressed gas-operated drive unit (10), comprising a gas motor (12) with a stator (20); with a rotor (24) rotating relative thereto about a rotary axis (22) when compressed air is applied to it, and having lamella slots (64.1, 64.2, 64.3, 64.4, 64.5) extending in the longitudinal direction and a rotor shaft (26) defining the rotary axis (22) and rotatably mounted on the stator (20) using end shields (32, 34); and with a sensor unit (56) with sensor element (58) which is aligned with a marking (61) coupled to the rotor (24) and which senses said marking for determining the speed of the rotor (24), characterized in that the lamella slots (64.1, 64.2, 64.3, 64.4, 64.5) of the rotor (24), which extend into an end face (60) of the rotor (24), are sensed as a marking (61), wherein the end face (60) faces one of the end shields (32, 34) and wherein the sensor element (58) is arranged in one of the end shields (32, 34) and is aligned with the lamella slots (64.1, 64.2, 64.3, 64.4, 64.5).

6. The method according to claim 5, characterized in< / b> that the lamella slots (64.1, 64.2, 64.3, 64.4, 64.5) are detected by the sensor element (58) contactlessly, in particular inductively, capacitively, optically and / or magnetically.

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