GEARBOX AND ACTUATOR

Description

[0001] The invention relates to a transmission comprising an input gear part and an output gear part and a first gear train which transmits a movement of the input gear part to the output gear part.

[0002] Such gearboxes are known and are used, for example, in actuators to adapt the speed and / or torque of a motor to external requirements.

[0003] The invention further relates to an actuator with a motor and an output shaft.

[0004] Actuators are known and are used to adjust mechanically adjustable control devices, such as fittings or valves or similar means for controlling fluid flows, for example flows of water or other liquids or of gases, by motor.

[0005] From EP 0 112 244 A1, a further development of motor drives is known which may or may not use a gearbox to drive a load in order to increase the efficiency of motion, speed and position specification.

[0006] From US 4953417 A a mechanical gear drive is known, in particular a multi-stage gear drive which is arranged between a driving and a driven wheel.

[0007] From JP S62 62038 A, on which the two-part form is based, a transmission device for a control unit is known in which the direction of rotation is switched between normal and reverse during operation.

[0008] From DE 42 29 439 A1, a device and a method for controlling the position of a movable part are known. The invention is based on the objective of providing a device for position control with a position encoder that includes an incremental encoder and an absolute encoder, in which the movement of mechanical end stops does not occur. Furthermore, the invention is based on the objective of providing a method for operating the position control.

[0009] A gear transmission is known from DE 385 431 C.

[0010] The invention is based on the objective of creating a gearbox with improved performance characteristics.

[0011] To solve the aforementioned problem, the features of claim 1 are provided according to the invention. In particular, to solve the aforementioned problem in a transmission of the type described above, it is proposed according to the invention that a second gear train is formed which, in addition to the first gear train, transmits the movement of the driving gear part to the driven gear part. Thus, a parallel transmission of forces or torques is provided, resulting in a natural overdetermination. The invention takes advantage of the fact that this overdetermination can be used to reduce backlash. This can be used particularly advantageously in transmissions that require backlash-free transmission. The operating characteristics are thus improved.

[0012] In one embodiment of the invention, a clamping device is provided which clamps the first gear train against the second gear train. This makes it possible to reduce or completely eliminate any existing play as required.

[0013] In one embodiment of the invention, the aforementioned tensioning device acts on a toothed part of the first gear train. This describes a simple method for introducing tension into the gear train.

[0014] In one embodiment according to the invention, the aforementioned clamping device has a return element. This allows for flexible clamping.

[0015] In an advantageous embodiment, the aforementioned clamping device can be configured to apply axial force to a gear tooth, in particular the gear tooth on which the clamping device acts. This allows for at least partial decoupling of the clamping force from the force and / or torque flow in the transmission train.

[0016] In one embodiment of the invention, the aforementioned clamping device engages axially with the shaft supporting the aforementioned toothed part on which the clamping device acts. This allows for an additional degree of freedom to be used to apply clamping force. This is particularly advantageous when the toothed part is arranged to be axially movable.

[0017] According to the invention, the clamping device is designed to act centrally and / or at a single point. This minimizes any interference with the rotational movement of the gearing component.

[0018] According to the invention, the clamping device engages with a spring-loaded ball. This provides a simple means that eliminates the need for the return element to rotate.

[0019] In an advantageous embodiment, the aforementioned toothed part on which the clamping device acts can be made of plastic. This allows for a lubrication-free coupling.

[0020] In particular, it can be provided that the first and / or second gear train is made of plastic. This allows for a simple finished product 3a.

[0021] In an advantageous embodiment, the aforementioned gear toothed section on which the clamping device acts can be arranged to be axially movable. This allows clamping to be introduced into the gear train via an additional degree of freedom.

[0022] In an advantageous embodiment, the aforementioned toothed part, upon which the clamping device acts and / or which is axially movable, may have helical teeth. Thus, axial movement can be easily converted into clamping of the first gear train.

[0023] It may be provided that the angle of inclination is selected such that self-locking is achieved. This prevents the clamping device from being driven backwards.

[0024] In an advantageous embodiment, the aforementioned toothed section, upon which the clamping device acts and / or which is axially movable, can be rotationally fixed to a further toothed section. This facilitates the transmission of torque along the first gear train.

[0025] In an advantageous embodiment, it can be provided that the aforementioned toothed part, on which the clamping device acts and / or which is axially movable, meshes with a counter-toothed part to which it is arranged to be axially movable.

[0026] In an advantageous embodiment, the first or second gear train can be designed as a gear drive. This makes the invention usable in an important application.

[0027] It is particularly advantageous if both gear trains are designed as gear drives.

[0028] In an advantageous embodiment, the first and second gear trains can be configured with matching gear teeth in pairs. This allows for a simpler design and reduces the number of parts required.

[0029] In an advantageous embodiment, the first and second gear trains can have the same number of gear stages. This makes synchronous operation of the gear trains easily achievable.

[0030] In an advantageous embodiment, the first and second gear trains can be configured to have the same gear ratio. This creates redundancy that can be used to brace the gear trains against each other.

[0031] In an advantageous embodiment, the driving gear element can be designed as a gear. This allows a rotary motion to be converted into a further motion with minimal or no backlash.

[0032] In an advantageous embodiment, the driven gear element can be designed as a gear. This allows for backlash-free or low-backlash conversion into a rotary motion.

[0033] It is particularly advantageous if both gear components are designed as a single gear. This allows for backlash-free or at least minimal backlash conversion of a rotary motion.

[0034] To solve this problem, the invention further proposes, in the case of an actuator, the features of the first independent claim relating to an actuator. In particular, to solve the aforementioned problem in an actuator of the type described above, it is proposed that a transmission according to the invention, as claimed, be arranged between the motor and the output shaft. This enables a backlash-free or at least low-backlash drive. The performance characteristics of an actuator are thus improved.

[0035] According to one embodiment, it can be provided that in an actuator having a motor and an output shaft, wherein a gearbox according to the invention can be arranged between the motor and the output shaft, wherein a position measuring device is provided which outputs an AB signal depending on a movement of the motor, wherein the position measuring device has an absolute encoder and a signal converter and the signal converter is configured to generate an AB signal from an absolute value of the absolute encoder.

[0036] The position measuring device is preferably arranged in the motor's drive train, for example on a motor shaft, an intermediate shaft, or the output shaft. This allows for the simulation of a signal that can be used, for example, in a control system based on the use of AB sensors. Thus, for example, a motor, an actuator, or a position measuring device can be replaced without requiring any adjustments to the control system. The performance characteristics of an actuator are therefore improved.

[0037] An AB signal can, for example, be characterized as a pair of temporally offset pulse sequences, where one pulse sequence can be used incrementally to determine the position of a movement and the direction of the movement can be derived from the temporally offset pulse sequence.

[0038] In an advantageous embodiment, the signal converter can be configured to generate at least one end-position signal. This allows for the simulation of further functionalities of the AB signal.

[0039] The end position signal can be displayed, for example, with a different pulse length and / or a different pulse pause length. This represents a particularly simple way to generate and / or evaluate end position markers.

[0040] The invention will now be described in more detail with reference to an exemplary embodiment, but is not limited to this embodiment. Further exemplary embodiments result from combining the features of one or more claims, as defined by the appended claims.

[0041] It shows Fig. 1 shows an actuator according to the invention in a three-dimensional oblique view from above, Fig. 2 shows a gearbox of the actuator made of Fig. 1with motor in an oblique view from below, Fig. 3 the gearbox made of Fig. 2 without engine in an oblique view from above and opposite Fig. 1 rotated approximately 180°, Fig. 4 the gearbox Fig. 2 in a three-dimensional side view, Fig. 5 a schematic representation of a position measuring device and Fig. 6 a schematic representation of a device equipped with the position measuring device according to Fig. 5 generated AB signal.

[0042] The Figures 1 to 4 will be described together below.

[0043] A in Fig. 1 The actuator shown and designated as a whole by 1 has a housing 2, a motor 3 (in the example an electric motor) and an output shaft 4 which can be driven by the motor 3.

[0044] Inside the housing 2 is a gearbox 5, which is located in the Figs. 2 to 4 is described in more detail.

[0045] The gearbox 5 has a driving gear part 6 which is arranged in a rotationally fixed manner on a motor shaft 7 of the motor 3.

[0046] The gearbox 5 further comprises an output gear section 8, which is fixedly mounted on the output shaft 4. The gearbox 5 transmits a rotary motion of the motor 3 to the output shaft 4.

[0047] Between the driving gear part 6 and the driven gear part 8, gear parts 9 are arranged which mesh with each other in pairs and thus form a first gear train 10.

[0048] Between the driving gear part 6 and the driving gear part 8, gear parts 11 are also arranged, which mesh with each other in pairs and thus form a second gear train 12.

[0049] The first gear train 10 and the second gear train 11 start at the driving gear part 6 and end at the driven gear part 8, thus transmitting the rotary motion of the motor 3 to the output shaft 4 in parallel and redundantly.

[0050] A clamping device 13 engages a toothed part 14. For this purpose, a return element 15, which is arranged under a cover 16 (in this example a spring), presses axially against a shaft 17. The shaft 17 carries the toothed part 14 and is arranged to be axially displaceable.

[0051] Here, a ball 36 is positioned between the return element 15 and the shaft 17 (see figure). Fig. 4 ) arranged, which contact the shaft 17 centrally and at a point.

[0052] The toothed part 14 has helical teeth 18 and meshes with a mating toothed part 19 with corresponding helical teeth 20. Due to the helix angle of the helical teeth 18, an axial movement of the shaft 17 is converted into a relative rotation of the toothed part 14 against the mating toothed part 19.

[0053] On the shaft 17, a further toothed part 21 is arranged in a rotationally fixed manner, which is also axially displaced by the axial movement of the shaft 17.

[0054] The further toothing part 21 has a straight toothing 22 and meshes with a neighboring toothing part 23, which also has a straight toothing 24.

[0055] In the aforementioned axial adjustment, the further toothed part 21 therefore shifts axially relative to the neighboring toothed part 23, without forcing a relative rotation.

[0056] The aforementioned relative rotation between the gear part 14 and the mating gear part 19 is transmitted via the second gear train 12 and to the neighboring gear part 23.

[0057] Since the further gear part 21 and the gear part 14 realize different helix angles, a preload of the first gear train 10 against the second gear train 12 results, independent of a rotational movement of the gear parts 9, 11 of the gearbox 5. Thus, any play between the motor 3 and the output shaft 4 is eliminated.

[0058] This means that the rotational position of the output shaft 4 can be accurately specified by the rotational position of the motor shaft 7.

[0059] In the exemplary embodiment, the gear teeth 6, 8, 9, 11 are designed as gears. The transmission 5 is therefore a gear transmission. The gear teeth 6, 8, 9, 11 are advantageously made of plastic, so that a lubrication-free transmission 5 can be achieved.

[0060] In the Figs. 2 to 4 It is evident that each gear tooth 9 of the gear train 10 corresponds to a gear tooth 11 of the second gear train 12, which is identical in construction and located in the same position. Thus, both gear trains 10 and 12 have the same number of gear stages and matching gear teeth 9 and 11 in pairs. The gear ratios of the two gear trains 10 and 12 are identical.

[0061] In further embodiments, the gear trains 10, 12 are designed differently from each other.

[0062] Fig. 5 The diagram shows the position determination of the motor shaft 7.

[0063] A position measuring device 25 is configured as an absolute encoder 35 and transmits its measured values ​​to a signal converter 26.

[0064] The signal converter 26 converts the received measured values, each representing an absolute rotational position of the motor shaft 7 or the output shaft 4, into an (incremental) AB signal 27 according to Fig. 6 um.

[0065] The AB signal 27 is generated as an A-track 28 and a B-track 29, which are time-shifted relative to each other by a time offset 30 in a known manner and each represents a pulse sequence whose pulses 31 indicate a movement of the motor shaft 7 by a specific angle of rotation. Depending on whether the motor shaft 7 or the output shaft 4 rotates clockwise or counterclockwise, the pulses 31 of the A-track 28 or the B-track 29 arrive earlier, resulting in a positive or negative time offset 30. The direction of rotation is determined by comparing the current absolute value with a previous value.

[0066] A different pulse length 33 and a different pulse pause length 34 are used by the signal converter 26 to generate an end position signal 32 when a stored absolute value of the motor shaft 7 or the output shaft 4 (for example, after a predetermined number of full revolutions) is reached.

[0067] In a gearbox 5, it is therefore proposed to form two parallel gear trains 10, 12 between an input gear part 6 and an output gear part 8. Reference symbol list

[0068] 1 Actuator 2 Housing 3 Motor 4 Output shaft 5 Gearbox 6 Input gear 7 Motor shaft 8 Output gear 9 Gear 10 First gear train 11 Gear 12 Second gear train 13 Clamping device 14 Gear 15 Return element 16 Cover 17 Shaft 18 Helical gear 19 Mating gear 20 Helical gear 21 Further gear 22 Straight gear 23 Adjacent gear 24 Straight gear 25 Position measuring device 26 Signal converter 27 AB signal 28 A track 29 B track 30 Time offset 31 Pulse 32 End position signal 33 Pulse length 34 Pulse pause length 35 Absolute encoder 36 Ball

Claims

1. Gear (5) having a driving toothed part (6) and a driven toothed part (8) and a first gear train (10) that transmits a movement of the driving toothed part (6) to the driven toothed part (8), wherein a second gear train (12) is formed which, in addition to the first gear train (10), transmits the movement of the driving toothed part (6) to the driven toothed part (8), wherein a clamping device (13) is formed which clamps the first gear train (10) against the second gear train (12), and the clamping device (13) has a return element so that flexible clamping can be introduced, characterized in that the clamping device (13) acts on a toothed part (14) of the first gear train (10) and in that the clamping device (13) acts axially on a shaft (17) carrying the toothed part (14) with a spring-loaded ball (36) centrically and / or at a single point.

2. Gear (5) according to the preceding claim, characterized in that the clamping device (13) preferably acts axially on the toothed part (14).

3. Gear (5) according to one of the preceding claims, characterized in that the toothed part (14), in particular the first gear train (10) and / or the second gear train (12), is / are made of plastic.

4. Gear (5) according to one of the preceding claims, characterized in that the toothed part (14) is arranged to be axially movable.

5. Gear (5) according to one of the preceding claims, characterized in that the toothed part (14) has helical teeth (18), in particular wherein a helix angle is selected such that self-locking is achieved.

6. Gear (5) according to one of the preceding claims, characterized in that the toothed part (14) is connected in a rotationally fixed manner to a further toothed part (21).

7. Gear (5) according to one of the preceding claims, characterized in that the toothed part (14) meshes with a counter-toothed part (19) relative to which it is arranged to be axially movable.

8. Gear (5) according to one of the preceding claims, characterized in that the first gear train (10) and / or the second gear train (12) is / are designed as a gear drive.

9. Gear (5) according to one of the preceding claims, characterized in that the first gear train (10) and the second gear train (12) have pairs of matching gear parts (9, 11) and / or a matching number of gear stages.

10. Gear (5) according to one of the preceding claims, characterized in that the first gear train (10) and the second gear train (12) realize a matching transmission ratio.

11. Gear (5) according to one of the preceding claims, characterized in that the driving toothed part (6) and / or the driven toothed part (8) is / are designed as a gearwheel.

12. Actuator (1) having a motor (3) and an output shaft (4), characterized in that a gear (5) according to one of the preceding claims is arranged between the motor (3) and the output shaft (4).

13. Actuator (1) according to the preceding claim 12, wherein a position measuring device (25) is provided which outputs an AB signal (27) depending on a movement of the motor (3), characterized in that the position measuring device (25) has an absolute value encoder (35) and a signal converter (26), and in that the signal converter (26) is designed to generate the AB signal (27) from an absolute value of the absolute value encoder (35).

14. Actuator (1) according to claim 13, characterized in that the signal converter (26) is designed to generate at least one end position signal (32), in particular with a deviating pulse length (33) and / or with a deviating pulse pause length (34).