Drive transmission device

Abstract

To substantially prevent reverse input of an output shaft, and reduce the number of rotations on an input side.SOLUTION: A drive transmission device includes: a pulley that rotates by receiving drive force; first drive transmission means for increasing the rotation of the pulley and transmitting the increased rotation; and second drive transmission means for reducing the rotation of the pulley transmitted by the first drive transmission means, transmitting the reduced rotation to an output shaft for outputting drive force by protruding in a central axis direction, and substantially preventing reverse input of the output shaft. The first drive transmission means is a gear train consisting of a plurality of two-stage gears having a small diameter gear which meshes with an input gear and a large diameter gear having a larger number of teeth than the small diameter gear, which meshes with an output gear, and increases the rotation of the pulley and transmits the increased rotation to the input shaft of the second drive transmission means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drive transmission device. [Background technology]

[0002] A shutter curtain drive device is known that drives a winding drum, which winds and unwinds a shutter curtain, to rotate around an axis, and is equipped with a drive motor and a reduction mechanism that reduces the rotational drive force of the drive motor and transmits it to the winding drum, the reduction mechanism being a paradox planetary gear mechanism that includes a sun outer gear fixed to the drive shaft of the drive motor, a planetary gear that meshes with the sun outer gear and rotates while revolving around the sun outer gear, a fixed internal gear that is non-rotatably arranged around the planetary gear and with which the planetary gear meshes, a movable internal gear that is coaxially arranged alongside the fixed internal gear and rotatable around the axis and with which the planetary gear meshes, and an output shaft that is fixed to the center of rotation of the movable internal gear and rotates the winding drum (Patent Document 1).

[0003] In a backlash-less mechanism of a planetary gear mechanism having three rotation elements, namely, a sun gear which is an external gear, a ring gear which is an internal gear arranged concentrically with the sun gear, and a carrier which holds planet gears meshing with the sun gear and ring gear so that the planet gears can rotate and revolve, and in which the sun gear, ring gear, and planet gears are all configured as tapered gears, a first elastic body and a second elastic body are provided which apply loads in opposite directions in the direction of the rotation center axis to any two of the three rotation elements. A backlash-less mechanism for a planetary gear mechanism is also known, which includes elastic bodies, wherein the first elastic body applies an elastic force to the carrier in the direction of the rotational center axis, and the second elastic body applies an elastic force to one of the ring gear and the sun gear in the direction of the rotational center axis, and the carrier is configured to be movable integrally with the planet gear in the direction of the rotational center axis by the elastic force received from the first elastic body, and one of the gears is configured to be movable in the direction of the rotational center axis by the elastic force received from the second elastic body (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-177405 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-90446 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention substantially prevents reverse input to the output shaft and reduces the rotation speed on the input side. [Means for solving the problem]

[0006] In order to solve the above problem, the drive transmission device according to claim 1 is A pulley that rotates when receiving a driving force; a first drive transmission means for transmitting the rotation of the pulley at an increased speed; a second drive transmission means for transmitting the rotation of the pulley transmitted by the first drive transmission means to an output shaft that projects in the direction of the central axis and outputs the drive force while substantially preventing reverse input of the output shaft; Equipped with It is characterized by:

[0007] The invention described in claim 2 is the drive transmission device described in claim 1, The first drive transmission means is a gear train consisting of a plurality of two-stage gears, including a small-diameter gear that meshes with the input gear and a large-diameter gear that has a greater number of teeth than the small-diameter gear and can mesh with the output gear, and accelerates the rotation of the pulley and transmits it to the input shaft of the second drive transmission means. It is characterized by:

[0008] The invention described in claim 3 is the drive transmission device described in claim 2, the second drive transmission means includes a sun gear that rotates by receiving a drive force via the first drive transmission means, a first internal gear that is fixedly disposed coaxially with the sun gear and has a first number of teeth, a second internal gear that is rotatably disposed coaxially with the sun gear and has a second number of teeth different from the first number of teeth, a plurality of planetary gears that mesh with the sun gear, the first internal gear, and the second internal gear and revolve while rotating on their axes, and a rotating member that supports the shafts of the planetary gears and rotates around its central axis by the revolution of the planetary gears, and decelerates the accelerated rotation of the pulley and transmits it to the output shaft provided at one end of the second internal gear, while substantially preventing reverse input of the output shaft. It is characterized by:

[0009] The invention described in claim 4 is the drive transmission device described in claim 3, The sun gear has an input gear having a smaller number of teeth than the large-diameter gear of the final-stage two-stage gear in the first drive transmission means, and the rotation of the final-stage two-stage gear is transmitted at an increased speed. It is characterized by:

[0010] The invention described in claim 5 is the drive transmission device described in claim 4, The gear train including the input gear is a spur gear. It is characterized by:

[0011] The invention described in claim 6 is the drive transmission device described in claim 4, All or a part of the gear train including the input gear is a helical gear. It is characterized by:

[0012] The invention described in claim 7 is the drive transmission device described in claim 3, the first internal gear has a convex shape on its outer circumferential surface, and the convex shape is fitted into a notch formed in a case body that houses the second drive transmission means therein, thereby fixing the first internal gear so as not to rotate; It is characterized by: [Effects of the Invention]

[0013] According to the invention as set forth in claim 1, it is possible to substantially prevent reverse input of the output shaft and reduce the rotation speed on the input side.

[0014] According to the invention as set forth in claim 2, the rotation speed on the input side can be reduced.

[0015] According to the invention as set forth in claim 3, reverse input of the output shaft can be substantially prevented.

[0016] According to the invention as set forth in claim 4, the rotation speed on the input side can be reduced.

[0017] According to the invention as set forth in claim 5, a large driving force can be transmitted.

[0018] According to the invention as set forth in claim 6, an increase in noise and vibration can be suppressed.

[0019] According to the seventh aspect of the invention, the first internal gear can be fixed unrotatably more reliably. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 2 is a partial cross-sectional perspective view showing the internal configuration of the drive transmission device according to the embodiment. [Figure 2] FIG. 2 is a diagram showing the overall configuration of a gear train in a drive transmission device. [Figure 3] 4A is a cross-sectional schematic diagram showing a gear train in a first drive transmission mechanism, and FIG. 4B is a diagram showing the gear train in the central axis direction of the first drive transmission mechanism. [Figure 4] FIG. 1(a) is a diagram showing the meshing of the first internal gear and the planetary gear, and FIG. 1(b) is a diagram showing the meshing of the second internal gear and the planetary gear. [Figure 5] 10A and 10B are diagrams illustrating support of a planetary gear by a rotating member. [Figure 6] (a) is a schematic front view of a horizontal blind, and (b) is a schematic plan view. DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, specific examples of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. It should be noted that in the following explanation using the drawings, the drawings are schematic and the ratios of the dimensions, etc. may differ from those of the actual product. For ease of understanding, illustrations of components other than those necessary for the explanation have been omitted as appropriate.

[0022] (1) Drive transmission device Figure 1 is a partially sectional oblique view showing the internal configuration of the drive transmission device 1 of this embodiment, Figure 2 is a line diagram showing the overall configuration of the gear train in the drive transmission device 1, Figure 3(a) is a schematic sectional view showing the gear train in the first drive transmission mechanism 20, (b) is a diagram showing the gear train in the central axis direction of the first drive transmission mechanism 20, Figure 4(a) is a diagram showing the meshing of the first internal gear 32 and the planetary gear, (b) is a diagram showing the meshing of the second internal gear 33 and the planetary gear, and Figure 5 is a diagram explaining the support of the planetary gear 34 by the rotating member 35. The configuration and operation of the drive transmission device 1 will be described below with reference to the drawings.

[0023] (1.1) Overall configuration of the drive transmission device As shown in Figure 1, the drive transmission device 1 is composed of a pulley 10 that rotates upon receiving a driving force from the outside, a first drive transmission mechanism 20 as an example of a first drive transmission means that accelerates and transmits the rotation of the pulley 10, a second drive transmission mechanism 30 as an example of a second drive transmission means that decelerates the rotation of the pulley 10 transmitted by the first drive transmission mechanism 20 and transmits it to an output shaft 40 that protrudes in the direction of the central axis c1 and outputs a driving force, and essentially prevents reverse input of the output shaft 40, a first support cover 50 that rotatably supports the pulley 10, a case body 60 that rotatably supports and houses the first drive transmission mechanism 20 and the second drive transmission mechanism 30, and a second support cover 70 that rotatably supports the output shaft 40, and essentially prevents reverse input of the output shaft 40 (rotational force from the output shaft 40) and reduces the rotation speed of the pulley 10, which is the input side, to transmit the rotation of the pulley 10 to the output shaft 40.

[0024] (1.2) Pulley As shown in FIG. 3, the pulley 10 comprises a disk-shaped pulley 11 around which a string (see operating cord 170 in FIG. 6) is wound to receive an external driving force, and an output gear 12 provided at the center of the pulley 11 and protruding axially from the pulley 11, and is rotatably supported by the first support cover 50. The pulley 10 rotates in the movement direction of the string wound around the pulley 11, for example, by moving the string in the vertical direction. The output gear 12 is provided concentrically and integrally with the pulley 11, and transmits the rotation of the pulley 11 to the first drive transmission mechanism 20. (1.3) First drive transmission mechanism The first drive transmission mechanism 20 is a gear train consisting of multiple two-stage gears 21, each having a small diameter gear and a large diameter gear with a greater number of teeth than the small diameter gear, and accelerates the rotation of the pulley 10 and transmits it to the sun gear 31, which is the input shaft of the second drive transmission mechanism 30.

[0025] 3 shows an example of the first drive transmission mechanism 20. The gear train is made up of a two-stage gear 21A that meshes with output gear 12 of pulley 10 to receive the rotation of pulley 10, a two-stage gear 21B that meshes with large diameter gear 21AB of double gear 21A to speed up the rotation of double gear 21A, and a two-stage gear 21C that meshes with large diameter gear 21BB of double gear 21B to speed up the rotation of double gear 21B.

[0026] Furthermore, the small-diameter gear 21AA of the double gear 21A, which meshes with the output gear 12 of the pulley 10 to receive the rotation of the pulley 10, has fewer teeth than the output gear 12, so that the rotation of the pulley 10 is transmitted at an increased speed. Furthermore, the sun gear 31, to which the rotation of the double gear 21C is input, has an input gear 31A with fewer teeth than the large-diameter gear 21CB of the double gear 21C, so that the rotation of the double gear 21C is transmitted at an increased speed. In this way, the first drive transmission mechanism 20 increases the speed on the input side of a gear train made up of a plurality of double gears 21 (when the double gears 21A, 21B, and 21C are not individually distinguished, they will be simply referred to as double gears 21), and also increases the speed on the output side, thereby achieving a larger speed-up ratio without increasing the number of stages of the double gear 21.

[0027] As shown in FIG. 2, if the number of teeth of the output gear 12 of the pulley 10 is Z1, the number of teeth of the small diameter gear of the double gear 21 is Z2, the number of teeth of the large diameter gear of the double gear 21 is Z3, and the number of teeth of the input gear 31A of the sun gear 31 is Z4, the speed increase ratio U1 is U1=(Z1 / Z2)*(Z3 / Z2)*(Z3 / Z2)*(Z3 / Z4) This becomes: For example, if Z1=16, Z2=9, Z3=16, and Z4=9, the speed increase ratio U1 is 9.98872.

[0028] By using helical gears for all or some of the output gear 12, the two-stage gear 21, and the input gear 31A, it is possible to suppress increases in meshing noise and vibration even at a large speed-up ratio. Furthermore, by using spur gears for the output gear 12, the two-stage gear 21, and the input gear 31A, it is possible to transmit a large driving force. Also, the output gear 12, the two-stage gear 21, and the input gear 31A may be a combination of a helical gear and a spur gear.

[0029] (1.4) Second drive transmission mechanism The second drive transmission mechanism 30 includes a sun gear 31 that rotates upon receiving driving force via the first drive transmission mechanism 20, a first internal gear 32 that is fixedly arranged coaxially with the sun gear 31 and has a first number of teeth Z1, a second internal gear 33 that is rotatably arranged coaxially with the sun gear 31 and has a second number of teeth Z2 different from the first number of teeth Z1, a plurality of planetary gears 34 that mesh with the sun gear 31, the first internal gear 32, and the second internal gear 33 and revolve while rotating on their own axes, and a rotating member 35 that supports the shafts 34a of the planetary gears 34 and rotates around the central axis c1 as the planetary gears 34 revolve, and is configured to decelerate the accelerated rotation of the pulley 10 and transmit it to an output shaft 40 provided at one end of the second internal gear 33, while substantially preventing reverse input of the output shaft 40.

[0030] (1.4.1) Sun gear The sun gear 31 is a two-stage gear including an input gear 31A and a large diameter gear 31B having a larger number of teeth than the input gear 31A, and is supported rotatably around a central axis c1. The input gear 31A meshes with the final stage two-stage gear 21C of the first drive transmission mechanism 20, and the large diameter gear 31B meshes with the planetary gear 34 to transmit the rotation of the pulley 10 to the planetary gear 34.

[0031] (1.4.2) First internal gear As shown in FIG. 4( a ), the first internal gear 32 is made up of a cylindrical body 321 having a hollow portion as a whole, and internal teeth 322 formed on the inner peripheral surface of the body 321 . The cylindrical body 321 has a convex shape 321a on its outer circumferential surface, and the convex shape 321a fits into a notch (not shown) formed in the case body 60 that houses the second drive transmission mechanism 30 therein, thereby fixing the cylindrical body 321 so as not to be rotatable.

[0032] The internal gears 322 have a first number of teeth Z1 and mesh with a planetary gear 34 rotatably supported on the rotating member 35, causing the planetary gear 34 to revolve around the central axis c1. Here, the planetary gear 34 has a tooth width that simultaneously meshes with a second internal gear 33 disposed opposite the first internal gear 32, and the second internal gear 33 has a second number of teeth Z2 that is greater than the first number of teeth Z1 of the first internal gear 32. For this reason, the first internal gear 32 is formed with a predetermined transition coefficient X1. Specifically, the transition coefficient X1 of the first internal gear 32 is greater than the transition coefficient X2 of the second internal gear 33 and is a positive value.

[0033] (1.4.3) Second internal gear As shown in FIG. 4( b ), the second internal gear 33 is made up of a cylindrical body 331 having a hollow portion as a whole, and internal teeth 332 formed on the inner peripheral surface of the cylindrical body 331 . As shown in FIG. 1, an output shaft 40 is provided at one end of the cylindrical body 331, protruding in the direction of the central axis c1 and concentric with the second internal gear 33, and the output shaft 40 is rotatably supported by a second support cover 70.

[0034] The internal gear 332 has a second number of teeth Z2 that is greater than the first number of teeth Z1, and meshes with the planetary gear 34 that is rotatably supported on the rotating member 35 and revolves around it. For this reason, the second internal gear 33 is formed with a predetermined transition coefficient X2. Specifically, the transition coefficient X2 of the second internal gear 33 is smaller than the transition coefficient X1 of the first internal gear 32 and is also a negative value.

[0035] (1.4.4) Rotating members and planetary gears 5, the rotating member 35 is disk-shaped and includes a first disk portion 351 and a second disk portion 352 facing the first disk portion 351, and three support shafts 35a that serve as rotation centers for the three planetary gears 34 are provided at equal intervals on the same circumference. A planetary gear 34 is inserted onto each support shaft 35a and is fixed by the first disk portion 351 and the second disk portion 352 so as not to move in the axial direction. The rotating member 35 is attached to the inner peripheral surface of the second internal gear 33 so as to be rotatable concentrically with the central axis c1.

[0036] The planetary gear 34 provided on the rotating member 35 is in mesh with the internal teeth 322 of the first internal gear 32 and the internal teeth 332 of the second internal gear 33 . The sun gear 31 is in mesh with a planetary gear 34 that is supported by a rotating member 35 and the inner peripheral surface of the cylindrical body 331 of the second internal gear 33 so as to be able to rotate and revolve about its axis. In the second drive transmission mechanism 30 configured in this manner, when the pulley 10 is driven to rotate, the rotation of the sun gear 31 causes the planetary gear 34 to rotate on its own axis and revolve inside the internal teeth 322 of the first internal gear 32, which is fixed non-rotatably to the case body 60, while meshing with the internal teeth 322. The planetary gear 34 supported by the rotating member 35 rotates while meshing with the internal teeth 332 of the second internal gear 33, which is rotatably supported on the inner surface of the second support cover 70, and the output shaft 40 formed concentrically and integrally with one end of the second internal gear 33 rotates.

[0037] As shown in FIG. 2, if the number of teeth of the large diameter gear 31B of the sun gear 31 is Za, the number of teeth of the planetary gear 34 is Zb, the number of teeth of the first internal gear 32 is Zc, and the number of teeth of the second internal gear 33 is Zd, the reduction ratio U2 is U2=(1+(Zc / Za)) / (1-(Zc / Zd)) This becomes:

[0038] For example, when Za=19, Zb=11, Zc=41, and Zd=44, the reduction ratio U2 is 46.3. In this case, the number of planetary gears 34 arranged is three. The difference in the number of teeth between the number of teeth Zc of the first internal gear 32 and the number of teeth Zd of the second internal gear 33, which simultaneously mesh with the planetary gear 34, is set equal to the number of arranged planetary gears 34 (=3), and the addendum modification coefficients corresponding to the respective numbers of teeth are set for the first internal gear 32 and the second internal gear 33 so that they mesh at the same axis distance. In this embodiment, when the addendum modification coefficients of the large diameter gear 31B of the sun gear 31, the planetary gear 34, the first internal gear 32, and the second internal gear 33 are Xa, Xb, Xc, and Xd, respectively, Xa=0.1, Xb=0.3, Xc=1.1, and Xd=-0.3.

[0039] As a result, when the rotation of the pulley 10 stops and an external reverse driving force acts on the output shaft 40, the reduction ratio U2 is large and the reverse input of the output shaft 40 (rotational force from the output shaft 40) is substantially prevented (self-locking action resulting in a locked state). Therefore, the rotation of the output shaft 40 can be maintained in one direction without using a one-way clutch spring or the like with a braking effect.

[0040] In this way, the second driving force transmission mechanism 30 has a large reduction ratio U2 and exhibits a self-locking effect, while the rotation speed of the input sun gear 31 is high. For example, if the reduction ratio U2 is 46.3, the sun gear 31 must rotate 46.3 times for the output shaft 40 to rotate once. Here, if the sun gear 31 is directly affected by the rotation of the pulley 10, the rotation of the pulley 10 will be the same as that of the sun gear 31.

[0041] In the drive transmission device 1 according to this embodiment, the rotation of the pulley 10 is transmitted to the sun gear 31 via the first drive transmission mechanism 20. The first drive transmission mechanism 20 accelerates the rotation of the pulley 10 at a speed-up ratio U1 and transmits the rotation. For example, when the speed-up ratio U1 is 9.98872, the reduction ratio U of the drive transmission device 1 is U2 / U1 (=4.63679), and the output shaft 40 rotates once when the pulley 10 rotates approximately five times. In other words, reverse input to the output shaft 40 is substantially prevented, and the rotation speed of the pulley 10 on the input side is reduced, making it possible to transmit the rotation of the pulley 10 to the output shaft 40.

[0042] (2) Operation of the drive transmission device FIG. 2 is a diagram showing the overall configuration of the gear train in the drive transmission device 1. Pulley 10 rotates upon receiving an external driving force. The rotation of pulley 10 is transmitted at an increased speed to two-stage gear 21A that meshes with output gear 12 of pulley 10, to two-stage gear 21B that meshes with large-diameter gear 21AB of two-stage gear 21A and accelerates the rotation of two-stage gear 21A, and to two-stage gear 21C that meshes with large-diameter gear 21BB of two-stage gear 21B and accelerates the rotation of two-stage gear 21B. The rotation of two-stage gear 21C is then transmitted to sun gear 31, which has an input gear 31A that has fewer teeth than large-diameter gear 21CB of two-stage gear 21C.

[0043] When the sun gear 31 is driven to rotate, each of the three planetary gears 34 rotatably supported by the rotating member 35 rotates around the support shaft 35a as the center of rotation. Furthermore, each of the three planetary gears 34 is meshed with the internal teeth 322 of the first internal gear 32 fixed to the case body 60, and therefore revolves along the inner circumferential surface of the first internal gear 32. When the three planetary gears 34 start to revolve, the rotating member 35 supporting the planetary gears 34 starts to rotate at a reduced speed relative to the rotation of the sun gear 31. When the rotating member 35 starts to rotate at a reduced speed, the planetary gears 34 supported by the rotating member 35 rotate while meshing with the internal teeth 332 of the second internal gear 33 that is rotatably supported by the second support cover 70, and the second internal gear 33 rotates at a reduced speed relative to the rotation of the rotating member 35. Then, the output shaft 40, which is provided concentrically with the second internal gear 33, rotates integrally with the second internal gear 33.

[0044] (3) Operation of the drive transmission device In the drive transmission device 1, the first drive transmission mechanism 20 is a gear train consisting of multiple two-stage gears 21, each of which has a small-diameter gear and a large-diameter gear with a greater number of teeth than the small-diameter gear. The first drive transmission mechanism 20 receives a driving force from an external source and rotates the pulley 10, accelerating its rotation and transmitting it to the second drive transmission mechanism 30. The second drive transmission mechanism 30 includes a first internal gear 32 fixedly disposed coaxially with the sun gear 31 and having a first number of teeth Z1, a second internal gear 33 having a second number of teeth Z2 different from the first number of teeth Z1, a plurality of planetary gears 34 meshing with the sun gear 31, the first internal gear 32, and the second internal gear 33 and revolving while rotating on their own axes, and a rotating member 35 rotatably supporting the planetary gears 34 and rotating as the planetary gears 34 revolve around the first internal gear 32, and transmits the rotation of the pulley 10, which is transmitted at an increased speed via the first drive transmission mechanism 20, to the output shaft 40 at a significantly reduced speed. This substantially prevents reverse input of the output shaft 40 and reduces the rotation speed of the pulley 10, which is on the input side, so that the rotation of the pulley 10 can be transmitted to the output shaft 40.

[0045] In the drive transmission device 1, the sun gear 31 has an input gear 31A with a smaller number of teeth than the large-diameter gear 21CB of the final-stage double gear 21C in the first drive transmission mechanism 20, and the rotation of the final-stage double gear 21C is accelerated and transmitted. As a result, the first drive transmission mechanism 20 increases the speed on the input side of the gear train made up of multiple double gears 21, and also increases the speed on the output side, thereby obtaining a larger speed-up ratio and reducing the rotation speed of the pulley 10 without increasing the number of stages of the double gears 21.

[0046] In the drive transmission device 1, when the gear train of the first drive transmission mechanism 20 including the input gear 31A of the sun gear 31 is configured with spur gears, a large drive force can be transmitted. Furthermore, when all or part of the gear train of the first drive transmission mechanism 20, including the input gear 31A of the sun gear 31, is made up of helical gears, increases in meshing noise and vibration can be suppressed even at large speed-up ratios.

[0047] In the drive transmission device 1, the first internal gear 32 has a convex shape 321a on its outer circumferential surface, and the convex shape 321a fits into a notch (not shown) formed in the case body 60 that houses the second drive transmission mechanism 30, thereby fixing the first internal gear 32 non-rotatably. This makes it possible to more reliably fix the first internal gear 32 non-rotatably.

[0048] (4) Drive unit using a drive transmission device The drive transmission device 1, which substantially prevents reverse input of the output shaft 40 and reduces the number of rotations of the pulley 10 on the input side to transmit the rotation of the pulley 10 to the output shaft 40, is applicable to lifting devices for sun shading devices such as horizontal blinds, pleated curtains, roll-up curtains, and roller screens.

[0049] "Example" Figure 6(a) is a schematic front view of a horizontal blind, and (b) is a schematic plan view. The horizontal blind 100 has multiple tiers of slats 130 suspended as sunshades via multiple ladder tapes 120 hanging down from a head box 110. The upper end of each ladder tape 120 is supported by a slat angle adjustment device (not shown) disposed within the head box 110, and the lower end is connected to a bottom rail 140.

[0050] Near the ladder tape 120, multiple lifting cords 150 hanging down from the head box 110 are inserted into the slats 130, and each lifting cord 150 has its upper end wound around a winding shaft 160 rotatably supported within the head box 110, and its lower end connected to the bottom rail 140.

[0051] A drive transmission device 1 is disposed inside one end of the head box 110. An endless operating cord 170, which is an example of a string, is wound around a pulley 11 of a pulley 10 of the drive transmission device 1, and the pulley 10 is rotated forward and backward by operating the operating cord 170.

[0052] The drive transmission device 1 rotates the output shaft 40 forward and backward based on the forward and backward rotation of the pulley 10. The output shaft 40 is fitted onto the winding shaft 160. When the output shaft 40 is rotated forward, the winding shaft 160 rotates in the winding direction of the lifting / lowering cord 150, so that the lifting / lowering cord 150 is wound onto the winding shaft 160, and the slats 130 and the bottom rail 140 are lifted up. When the output shaft 40 is rotated backward, the winding shaft 160 rotates in the unwinding direction of the lifting / lowering cord 150, so that the slats 130 and the bottom rail 140 are lowered.

[0053] Based on the forward and reverse rotation of the winding shaft 160, the slat angle adjustment device operates in parallel with the raising and lowering movement of the slats 130, and each slat 130 is rotated in the same phase via the ladder tape 120. After each slat 130 has been rotated to a substantially vertical direction, the slats 130 are raised and lowered in a state where further rotation in the vertical direction is prevented.

[0054] In the embodiment, an example of a case where an external driving force for reverse rotation acts on the output shaft 40 is the weight of the slats 130 and the bottom rail 140 when they are pulled up. When an external driving force for reverse rotation acts on the output shaft 40, the drive transmission device 1 has a large reduction ratio U2, and the reverse input of the output shaft 40 is substantially prevented. This prevents the pulled-up slats 130 and the bottom rail 140 from slipping or falling. Furthermore, when the raising and lowering of the slats 130 and the bottom rail 140 is stopped while they are being raised and lowered, the slats 130 and the bottom rail 140 stop as they are, and the phenomenon of them dropping slightly and stopping does not occur. In the drive transmission device 1, the rotation of the pulley 10 is transmitted at an increased speed to the second drive transmission mechanism 30 via the first drive transmission mechanism 20, thereby reducing the number of rotations of the pulley 10 required for lifting and lowering, i.e., reducing the amount of operation of the operating cord 170.

[0055] In the embodiment, an example has been described in which the drive transmission device 1 is applied to a lifting device for a solar shading device, but the drive transmission device 1 can also be used as a geared motor with a self-locking effect in which a motor as a drive source is integrally connected to the pulley 10. [Explanation of symbols]

[0056] 1. Drive transmission device 10 Pulley 20... First drive transmission mechanism, 21A, 21B, 21C... Two-stage gear 30... Second drive transmission mechanism, 31... Sun gear, 32... First internal gear, 33... second internal gear, 34... planetary gear, 35... rotating member 40···Output shaft 50...1st support lid body 60··Case body 70...Second support lid body 100···Lifting device, 110···Head box, 120···Ladder tape, 130···Slat, 140···Bottom rail, 150···Lifting cord, 160··· Winding shaft, 170··· Operation cord

Claims

1. A pulley that rotates when receiving a driving force; a first drive transmission means for transmitting the rotation of the pulley at an increased speed; a second drive transmission means for transmitting the rotation of the pulley transmitted by the first drive transmission means to an output shaft that projects in the direction of the central axis and outputs the driving force while reducing the speed of the rotation, and for substantially preventing reverse input of the output shaft; Equipped with A drive transmission device characterized by:

2. the first drive transmission means is a gear train consisting of a plurality of two-stage gears, including a small-diameter gear that meshes with the input gear and a large-diameter gear that has a greater number of teeth than the small-diameter gear and is capable of meshing with the output gear, and the first drive transmission means accelerates the rotation of the pulley and transmits the increased rotation to the input shaft of the second drive transmission means; 2. The drive transmission device according to claim 1.

3. the second drive transmission means includes a sun gear that rotates by receiving a drive force via the first drive transmission means, a first internal gear that is fixedly disposed coaxially with the sun gear and has a first number of teeth, a second internal gear that is rotatably disposed coaxially with the sun gear and has a second number of teeth different from the first number of teeth, a plurality of planetary gears that mesh with the sun gear, the first internal gear, and the second internal gear and revolve while rotating on their axes, and a rotating member that supports the shafts of the planetary gears and rotates around its central axis by the revolution of the planetary gears, and decelerates the accelerated rotation of the pulley and transmits it to the output shaft provided at one end of the second internal gear, while substantially preventing reverse input of the output shaft.

3. The drive transmission device according to claim 2.

4. the sun gear has an input gear having a smaller number of teeth than the large-diameter gear of the final-stage two-stage gear in the first drive transmission means, and rotation of the final-stage two-stage gear is transmitted at an increased speed.

4. The drive transmission device according to claim 3.

5. The gear train including the input gear is a spur gear.

5. The drive transmission device according to claim 4.

6. All or a part of the gear train including the input gear is a helical gear.

5. The drive transmission device according to claim 4.

7. the first internal gear has a convex shape on its outer circumferential surface, and the convex shape is fitted into a notch formed in a case body that houses the second drive transmission means therein, thereby fixing the first internal gear so as not to rotate; 4. The drive transmission device according to claim 3.

Images