Door drive and door system

Abstract

A door operator, in particular a swing door operator, comprises an electric motor for providing motor torque, an output shaft suitable for being coupled via a lever or linkage to a door frame or leaf to provide opening torque and to actively move the door from its closed position to its open position and / or to hold it in its open position, and a multi-stage gearbox that couples the electric motor to the output shaft. The gearbox comprises an input stage with an input element for supplying the motor torque, an output stage with an output element that is rotationally fixed to the output shaft, and at least one intermediate gear stage between the input stage and the output stage. The gear stage on the output shaft has a module of 1.5 mm or more and is sintered.

Description

[0001] The invention relates to a door drive, in particular a revolving door drive, comprising an electric motor, an output shaft, and a multi-stage gear. Furthermore, the invention relates to a door system, in particular a revolving door system, comprising a door with a frame and a leaf pivotably mounted on the frame, and a door drive, wherein the output shaft of the door drive is coupled to the frame or the leaf.

[0002] (Revolving) door drives are designed to actively move a door, particularly a revolving door such as a swing door, from its closed position to its open position and to hold it in this open position. For this purpose, such door drives are usually mounted on a fixed component such as a door frame. Their output shaft is connected to a sliding block and a slide rail via a linkage or a lever with a door leaf. Due to the dimensions of the frame, such door drives must be as compact as possible. In particular, the door drive should normally not exceed a height of approximately 70 mm. At the same time, door drives should, of course, be as cost-effective as possible.

[0003] It is therefore an object of the present invention to provide a door drive which is compact and inexpensive to manufacture.

[0004] This problem is solved by the subject matter of the independent claims. Advantageous further developments are the subject matter of the dependent claims and emerge from the description and the drawings.

[0005] The door drive according to the invention can, in particular, be a revolving door drive and comprises an electric motor for providing a motor torque, an output shaft suitable for being coupled to a frame or a leaf of a door via a lever or a linkage in order to provide an opening torque and actively move the door from its closed position to its open position and / or to hold it in its open position, and a multi-stage transmission that couples the electric motor to the output shaft. The transmission has an input stage with an input element for feeding the motor torque, an output stage with an output element that is rotationally fixedly connected to the output shaft, and at least one gear intermediate stage between the input stage and the output stage. The output element is sintered and has a modulus of 1.5 mm or more.

[0006] The output element is the gear stage on the output shaft.

[0007] Additional gear stages can also be sintered.

[0008] The module of the gear stage on the output shaft (module of the output element) can optionally be 1.75 mm to 3.25 mm, preferably 2 mm to 3 mm, in particular 2.5 mm.

[0009] The module is a measure of the size of a gear's teeth, familiar to those skilled in the art, and is expressed in millimeters. The module m corresponds to the pitch diameter d of the gear divided by the number z of teeth on the gear: m = d z

[0010] The modulus is therefore an important parameter for gear design. Depending on the load to which the gears are subjected, the modulus must be selected accordingly so that the teeth are large enough to bear the load.

[0011] Preferably, the gear of the initial stage and the gears of the intermediate gear stage(s) are sintered, particularly for cost reasons, as this allows for cost savings of over 50% compared to machined gears. However, due to the modulus of the initial stage of 1.6 mm or more, it is possible to compensate for the typically lower strength of the sintered material, such as sintered steel, so that the gears allow for significant cost savings while still offering strength equivalent to machined gears.

[0012] Typically, the speed and torque are changed within a gear stage, although this is not necessarily the case. Gear stages can be designed as gear stages or belt stages, for example. In the context of the present invention, the input stage refers to the gear stage that has the input element through which the engine torque is fed. The output stage refers to the gear stage that has the output element to which the output shaft is connected in a rotationally fixed and, in particular, coaxial manner. The intermediate gear stage(s) connect(s) the input stage and the output stage to one another.

[0013] The output shaft is usually connected to a door frame or leaf via a lever or rod. The lever may, for example, have a sliding block at its end, which is guided in a slide rail attached to the frame or leaf. The rod may, in particular, be a scissor-type rod, the end of which is attached to the frame or leaf.

[0014] In an advantageous embodiment, the electric motor is a brushless DC motor, also known as a BLDC motor. BLDC motors can be relatively short or flat, which has a positive effect on the compactness of the door drive. Due to their compact design, the BLDC motor can be installed so that its output shaft runs transversely to the gearbox. At the same time, BLDC motors are comparatively light for the same power, especially compared to other DC motors.

[0015] The BLDC motor has a rated speed of approximately 3700-5600 revolutions per minute. Other DC motors have comparable rated speeds of 1500-2500 revolutions per minute. To achieve the same speed at the output shaft, the overall gear ratio is approximately 500-600 instead of 250-300.

[0016] Preferably, the electric motor has an output shaft that is non-rotatably connected to the input element for transmitting the motor torque to the input element. The input stage further comprises a driven gear driven by the input element, and the axis of the output shaft runs parallel to the rotational axis of the driven gear. In particular, the input stage can be designed as a belt stage. This configuration enables higher transmission efficiency compared to solutions in which the axis of the output shaft runs transversely to the rotational axis of the driven gear. For example, the efficiency loss is approximately 30% if the input stage is a helical gear stage or worm gear stage, whereas only approximately 5% efficiency is lost with spur gear or belt gear stages.

[0017] The gearbox can have at least four, in particular exactly four, gear stages. Previously known door drives typically have three gear stages. A four-stage gearbox can reduce higher rated speeds of the electric motor and achieve a higher torque at the output element. The use of a BLDC motor, for example, can result in a higher rated speed compared to other DC motors. For example, the rated speed can be in the range of 3,700 rpm to 5,600 rpm. To still achieve a comparable door opening time, a higher gear ratio in the gearbox and thus a fourth gear stage is desirable.

[0018] The gear wheel of the intermediate gear stage(s) can be formed as a single-piece combination gear element with the pinion of the respective subsequent gear stage. Such combination gear elements can be easily manufactured by sintering. Furthermore, the single-piece design eliminates the need for additional connecting elements such as feather keys or joining processes, which is also advantageous for achieving good strength.

[0019] Preferably, the gear wheel of the intermediate gear stage or the gear wheels of the intermediate gear stages each have a mounting bore for a ball bearing to support the respective gear wheel on a journal of a transmission housing. The ball bearing can be fitted into the mounting bore with its outer ring and hold the gear wheel in position. Instead of a protruding bearing journal, a mounting bore is used, which can be easily manufactured by sintering and also results in a compact design.

[0020] In a preferred embodiment, the input stage has a pulley with a particularly annular recess, wherein a pinion of the subsequent intermediate gear stage is arranged on the pulley in a rotationally fixed manner. A bearing portion of a housing of the transmission extends into the recess and accommodates a ball bearing for the pinion to support the pinion and the pulley on the housing. The pulley and pinion can be connected to each other in a rotationally fixed manner, for example, by a bolt, a key, a splined shaft, or by similar known means.

[0021] The output stage is preferably designed as a gear stage. This contributes to high efficiency and good, cost-effective manufacturing.

[0022] A return element can be provided that is connected to the output element in a rotationally fixed manner, in particular one that is formed integrally therewith, and is designed to interact with a mechanical energy store to bring about an automatic movement of the door into the closed position when the motor torque is lost. The mechanical energy store can in particular be a spring that is tensioned when the door is opened. If the motor torque is lost, for example in the event of a power failure, the tensioned spring causes the door to close. The return element preferably has a heart-shaped cam disc on which a pressure roller of the door drive, coupled to the mechanical energy store, rolls.

[0023] In an advantageous embodiment, the output shaft comprises internal gearing, in particular internal serrations, for engaging a corresponding gearing of a lever or linkage of the door drive. This reliably ensures that the rotation of the output element leads to an opening movement of the door leaf.

[0024] The invention also relates to a door system, in particular a revolving door system, comprising a door with a frame and a leaf pivotably mounted on the frame, as well as the previously described door drive. The output shaft is coupled to the frame or leaf.

[0025] The invention is explained below merely by way of example with reference to the schematic drawings. Fig. 1 a perspective view of a door drive according to an embodiment, Fig. 2 a perspective view of the gear of the door drive from Fig. 1, Fig. 3 another perspective view of the door drive gear from Fig. 1 , Fig. 4 a sectional view of the door drive from Fig. 1 according to section plane IV, Fig. 5 a sectional view of the door drive from Fig. 1 according to section plane V and Fig. 6 a sectional view of the door drive from Fig. 1 corresponding to section plane VI.

[0026] Fig. 1 shows a perspective view of a door drive 10, with the housing of the door drive 10 hidden. The door drive 10 has an electric motor 11, which in the present embodiment is designed as a brushless direct current motor, also referred to as a BLDC motor.

[0027] Preferably, a BLDC external rotor motor is used, with its motor axis arranged parallel to the output stage axis. The external rotor is equipped with ferrite magnets, unlike internal rotors, which are often built with more expensive and stronger neodymium magnets. The larger effective radius of the external rotor partially compensates for the lower magnetic force.

[0028] In addition, the door drive 10 has an output shaft 67 with an internal toothing 61, namely an internal spline. The internal toothing 61 serves to engage a lever or rod (not shown) with a corresponding external toothing. The output shaft 67, coupled to a frame or leaf of a door via the lever or rod, provides an opening torque to actively move the door from its closed position to its open position and / or to hold it in its open position.

[0029] The door drive 10 further comprises a gear 13. The gear 13 is connected between the electric motor 11 and the output shaft 67, so that a motor torque fed into the gear 13 by the electric motor 11 leads, via the gear stages, to the rotation of the output shaft 67 and thus of the lever or linkage. The electric motor 11, the gear 13, and the output shaft 67 are accommodated in a housing 15, which is composed of two housing parts 15a, 15b (see FIG. Fig. 4 to 6 ) which are connected to each other by means of connecting elements such as screws, pins or bolts.

[0030] How Fig. 2 and 3 show, the transmission 13 in the present embodiment has four gear stages, namely an input stage 17, an output stage 21 and two gear intermediate stages 25, 27. Typically, each stage serves to change the speed and the torque.

[0031] The input stage 17 is designed as a belt stage and comprises a driven pulley 31 and an input element 19 in the form of a smaller, driving pulley that can be engaged with an output shaft (not shown) of the electric motor 11 to transmit the motor torque to the input element 19. A toothed belt 29 is engaged with the input element 19 and the pulley 31, so that the pulley 31 is driven by the input element 19 by means of the belt 29.

[0032] The pulley 31 is, as can be seen from Fig. 2 and 6As can be seen, it is non-rotatably connected to a gear 33, which meshes with another gear 35. The gear 33 and the gear 35 together form the first intermediate gear stage 25, with the gear 33 acting as a pinion and the gear 35 as a wheel. In the present case, the intermediate gear stage 25 is designed as a straight-toothed gear stage. In other embodiments, it is also conceivable for the intermediate gear stage 25 to be helical-toothed.

[0033] The gear 35 is, as can be seen from Fig. 2 and 5 As can be seen, it is formed as a combination gear element with a gear 37, wherein the gear 37 functions as the pinion of the subsequent gear stage, namely the second intermediate gear stage 27. The gear 37 meshes with a gear 39, which functions as the wheel of the intermediate gear stage 27.

[0034] The gear 39 is, as can be seen Fig. 2 and 4As can be seen, it is designed as a combination gear element with a gear 41, wherein the gear 41 functions as the pinion of the subsequent gear stage, namely the output stage 21. The gear 41 meshes with a gear 43, which functions as the wheel and output element 23 of the output stage 21. The output stage 21 is also designed as a straight-toothed gear stage.

[0035] The output element 23 of the output stage 21 is connected in a rotationally fixed manner to the output shaft 67. Due to the torque transmission to the output element 23, the output shaft 67 is thus set in rotation.

[0036] Formed in one piece with the output element 23 is a Fig. 2The return element 59 is shown. The return element 59 comprises a heart-shaped cam disk, on which a pressure roller of the door drive 10 rolls, coupled to a mechanical energy storage device (also not shown). The mechanical energy storage device can, in particular, be a spring that is tensioned when the door is opened by means of the electric motor 11 and the gear 13. If the motor torque subsequently ceases, for example due to a power failure, the spring relaxes, so that the pressure roller exerts pressure on the cam disk and rotates the output shaft 67 back against the opening direction. The door then moves automatically into its closed position.

[0037] The gears 33, 35, 37, 39, 41, 43 of the intermediate gear stages 25, 27 and the output stage 21 are sintered. In the present embodiment, the gears 41, 43 of the output stage 21 have a modulus m of approximately 1.5 mm to 3 mm to compensate for the somewhat lower strength of the sintered steel compared to machined steel gears and to achieve the required service life.

[0038] In order to be able to sinter the wheel 39 of the gear intermediate stage 27 with the pinion 41 of the output stage 21 as one part, the combination gear element is provided on the side of the wheel 39 with no bearing journal, but with a receiving bore 47 for a ball bearing 49, as Fig. 4This also facilitates production by sintering. The ball bearing 49 holds the wheel 39 in position with its outer ring, while a pin 53 of the housing part 15b engages in the ball bearing bore and receives the inner ring of the ball bearing 49. This allows the dimensions of the door drive 10 to be kept correspondingly compact. Similarly, Fig. 5 shows the wheel 35 of the intermediate gear stage 25, which has a receiving bore 45 for a ball bearing 49. The ball bearing 49 holds the wheel 35 in position with its outer ring, while a pin 51 of the housing part 15a engages in the ball bearing bore and receives the inner ring of the ball bearing 49. Another ball bearing 49 has its inner ring in a fitted connection with an outer bearing pin 63 of the pinion 37. The outer ring of this ball bearing 49 is received in the housing part 15b.

[0039] How Fig. 2 , 5 and 6As shown, the pulley 31 has an annular recess 55. A bearing portion 57 of the housing part 15a extends into the recess 55 and accommodates a ball bearing 49 for the pinion 33 of the intermediate gear stage 25, in order to support the pinion 33 and the pulley 31 on the housing 15. Another ball bearing 49 is in a fitted connection with its inner ring to an outer bearing pin 65 of the pinion 33.

[0040] The illustrated embodiment corresponds overall to a door drive 10 that is inexpensive to manufacture due to the use of sintered gears, yet whose gears still exhibit sufficient strength. Furthermore, the door drive 10 is extremely compact and lightweight due to the use of the BLDC motor 11 and the design of the gears and housing 15. Finally, the belt drive stage, in particular, instead of a worm drive stage, ensures significantly higher efficiency.

[0041] In addition to the two bearings, the output element 23 has three functional areas, namely the gear 43, the heart cam of the return element 59 and the internal toothing 61. Ideally, the three functional areas are manufactured in one sintering process, which significantly reduces costs.

[0042] If the output element 23 were turned and milled from solid, the gear 43 would have to be milled, the return element 59 would have to be milled, and the internal toothing 61 would have to be broached. Due to the large chip volume, the output element would then be very expensive.

[0043] Even if the return element 59 had to be milled and the internal toothing 61 had to be cleared in the sintered starting element 23, the chip volume and costs would be significantly smaller than if it were manufactured from solid material by machining. List of reference symbols

[0044] 10 Door drive 11 Electric motor 13 Gearbox 15 Housing 15a Housing part 15b Housing part 17 Input stage 19 Input element 21 Output stage 23 Output element 25 Intermediate gear stage 27 Intermediate gear stage 29 Belt 31 Belt pulley 33 Gear 35 Gear 37 Gear 39 Gear 41 Gear 43 Gear 45 Mounting hole 47 Mounting hole 49 Ball bearing 51 Pin 53 Pin 55 Recess 57 Bearing section 59 Return element 61 Internal toothing 63 Bearing pin 65 Bearing pin 67 Output shaft

Claims

1. A door drive (10), in particular a revolving door drive, comprising an electric motor (11) for providing a motor torque, an output shaft (67) suitable for being coupled to a frame or a leaf of a door via a lever or a linkage in order to provide an opening torque and actively move the door from its closed position to its open position and / or to hold it in its open position, and a multi-stage transmission (13) coupling the electric motor (11) to the output shaft (67), wherein the transmission (13) comprises an input stage (17) with an input element (19) for feeding in the motor torque, an output stage (21) with an output element (23) that is connected in a rotationally fixed manner to the output shaft (67), and at least one gear intermediate stage (25, 27) between the input stage (17) and the output stage (21), and wherein the output element (23) sintered and has a modulus of 1.5 mm or more.

2. Door drive (10) according to claim 1, characterized in that the output element (23) with the gear (43), the return element (59) and the internal toothing (61) is fully sintered, or that the return element (59) is milled and the internal toothing (61) is cleared.

3. Door drive (10) according to claim 1 or 2, characterized in that the module of the output element (23) is 1.5 mm to 3.25 mm, preferably 2 mm to 3 mm, in particular 2.5 mm.

4. Door drive (10) according to one of the preceding claims, characterized in that the electric motor (11) is a brushless DC motor, preferably an external rotor motor, whose drive shaft is parallel to the output shaft (67).

5. Door drive (10) according to one of the preceding claims, characterized in that the input stage (17) is designed as a toothed belt stage.

6. Door drive (10) according to one of the preceding claims, characterized in thatthe transmission (13) has at least four, in particular exactly four, transmission stages (17, 21, 25, 27).

7. Door drive (10) according to one of the preceding claims, characterized in that the wheel (35, 39) of the gear intermediate stage (25, 27) or the wheels (35, 39) of the gear intermediate stages (25, 27) is or are formed as a combination gear element in one piece with the pinion (37, 41) of the respective subsequent gear stage (21, 27).

8. Door drive (10) according to one of the preceding claims, characterized in that the wheel (35, 39) of the gear intermediate stage (25, 27) or the wheels (35, 39) of the gear intermediate stages (25, 27) each have a receiving bore (45, 47) for a ball bearing (49) for mounting the respective wheel (35, 39) on a pin (51, 53) of a housing (15) of the transmission (13).

9. Door drive (10) according to one of the preceding claims, characterized in thatthe input stage (17) has a belt wheel (31) with a particularly annular recess (55), wherein a pinion (33) of the subsequent gear intermediate stage (25) is arranged in a rotationally fixed manner on the belt wheel (31), and wherein a bearing section (57) of a housing (15) of the transmission (13) dips into the recess (55) and accommodates a ball bearing (49) for the pinion (33) in order to mount the pinion (33) and the belt wheel (31) on the housing (15).

10. Door drive (10) according to one of the preceding claims, characterized in that the output stage (21) is designed as a gear stage.

11. Door drive (10) according to one of the preceding claims, characterized in thata return element (59) is provided which is connected to the output element (23) in a rotationally fixed manner and, in particular, is formed integrally therewith and is designed to cooperate with a mechanical energy store in order to bring about an automatic movement of the door into the closed position when the motor torque ceases.

12. Door drive (10) according to claim 11, characterized in that the return element (59) has a heart-shaped cam disc on which a pressure roller of the door drive (10) coupled to the mechanical energy storage device rolls.

13. Door drive (10) according to one of the preceding claims, characterized in that the output shaft (67) has an internal toothing (61), in particular an internal serration, for engaging a corresponding toothing of a lever or a linkage of the door drive (10).

14. Door system, in particular a revolving door system, comprising a door with a frame and a leaf pivotably mounted on the frame and a door drive (10) according to one of the preceding claims, wherein the output shaft (67) is coupled to the frame or the leaf.

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