JP3942353B2 - Clutch device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a clutch device that is used in a device such as a blind and switches between connection and non-connection of two shafts.
[0002]
[Prior art]
In conventional devices such as blinds, various clutch devices that selectively switch connection / disconnection between the drive-side shaft and the non-drive-side shaft are used. For example, there is one described in Japanese Patent Application Laid-Open No. 4-149390. In this clutch device, one end of a screen is provided at one end of a take-up shaft attached so as to be wound and unwound, and a spring shaft supported by a support bracket and a spring shaft are adjacent to each other. A first spring drum and a second spring drum that are rotatably supported, a clutch spring provided across these two spring drums, and an intermediate portion thereof rotatably supported by the first spring drum And a clutch arm that can be rotated by rotation of the pulley. One end of the clutch spring is locked to the first spring drum, and the other end is locked to the tip of the clutch arm. The first spring drum is rotatable by a pulley, and the second spring drum is connected to the take-up shaft. When the pulley is rotated in a certain direction, the first spring drum follows and rotates in that direction, and the clutch spring tightens the first and second spring drums. Rotates in the screen unwinding direction. Further, when the pulley is rotated in the opposite direction, the tip end portion of the clutch arm is rotated in a predetermined direction to loosen the clutch spring and reduce the frictional force between the clutch spring and the second spring drum. Can idle.
[0003]
However, in the case of the clutch device using the clutch spring as described above, when a large torque is momentarily applied when the clutch spring tightens both drums, the diameter of the clutch spring instantaneously shrinks to a predetermined amount or more, There is a problem in that the clutch spring may bite into the seam that becomes the boundary line between the two drums, causing malfunction.
[0004]
As means for solving such a problem, for example, one described in JP-A-7-233684 has been proposed. In this publication, a clutch adapter and a clutch spring receiver, which are relatively rotatable and arranged concentrically along the axial direction, and winding between the clutch adapter and the clutch spring receiver are wound. And a clutch surface having a cam surface engageable with the clutch adapter. The clutch is rotatable by a predetermined angle with respect to the clutch spring receiver, and the clutch cam surface The adapter can be pushed out in the direction of the clutch spring receiver. The boundary line between the clutch adapter and the clutch spring receiver is applied by momentarily applying the pushing force from the cam surface of the clutch to the clutch adapter and the rotational force when the screen is rotated in the screen winding direction from the screen. The clutch spring is tightened without biting into the joint, and the clutch adapter is connected to the clutch spring receiver.
[0005]
[Problems to be solved by the invention]
However, although the latter publication can prevent the clutch spring from biting, there is a problem that the number of parts increases.
[0006]
The present invention has been made in view of such a conventional problem, and provides a clutch device capable of preventing a clutch spring from biting into a joint between two shafts constituting the clutch device without increasing the number of parts. The purpose is to do.
[0007]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 includes a driving side shaft and a non-driving side shaft that are relatively rotatable and arranged concentrically along the axial direction, and these two shafts. In a clutch device having a clutch spring wound around and selectively switching between coupling and non-coupling of two shafts by using tightening and relaxation of the clutch spring, a driving side shaft and a non-driving side shaft At least one of them is provided with a forced tilting means for forcibly tilting a portion of the clutch spring passing through the boundary line between the driving side shaft and the non-driving side axis with respect to the boundary line, A rib integrally formed at a boundary end portion of at least one of the driving side shaft and the non-driving side shaft, and a notch portion formed in the rib, and the rib is disposed so as to straddle the boundary line, and the clutch spring The part of that passes through the notch of the rib And butterflies. The forced inclination means causes the clutch spring to pass through the boundary line between the two shafts, so that the clutch spring can be prevented from biting into the boundary line.
[0008]
Further, the forced tilting means can be configured with a simple configuration of ribs and notches.
[0009]
According to a second aspect of the present invention, the rib according to the first aspect is formed with an inclined surface that is inclined with respect to a boundary line adjacent to the notch, and the inclined surface defines a portion of the clutch spring. It is characterized by guiding toward the notch. The inclined surface can smoothly guide the clutch spring toward the notch.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 are views showing an embodiment of a clutch device according to the present invention.
[0011]
In this embodiment, a clutch device used for a blind is taken as an example, and the blind can be applied to any blind such as a horizontal blind, a roman shade, a roll screen, etc. An example is shown in which the other end of the lifting / lowering cord having one end attached to the lower part is wound around a winding drum, is detachably mounted, and the winding drum is connected so as to rotate integrally with the winding shaft 10. When the shielding material rises, the winding shaft 10 rotates in a predetermined direction, so that the winding drum rotates integrally, the lifting cord is wound around the winding drum, and the shielding material rises. On the contrary, when the shielding material descends, the lifting / lowering cord is unwound from the winding drum, and the winding drum and the winding shaft 10 rotate in the opposite direction. Thus, the winding shaft 10 is configured to rotate in conjunction with the lifting and lowering of the shielding material when the shielding material is raised and lowered, and the clutch device 20 including the stopper mechanism is connected to the winding shaft 10. Further, the speed reduction device 40 is connected via the clutch device 20. Of course, the present invention is not limited to this example. For example, in the case of a roll screen, it is possible to connect the clutch device 20 to a take-up pipe attached so that one end of the shielding material is taken up and unwound. It is.
[0012]
The clutch device 20 includes a case 22, an input shaft 24 through which the winding shaft 10 passes and rotates integrally with the winding shaft 10, and an outer peripheral side of a bearing portion 24 a that is reduced in diameter from one end of the input shaft 24 and extends. And a clutch shaft 25 that is externally fitted so as to be relatively rotatable. Therefore, the input shaft 24 and the clutch shaft 25 are arranged in a concentric manner along the axial direction so as to be relatively rotatable, and the outer diameters of the outer peripheral surfaces thereof are the same. A coiled clutch spring 30 is wound around the outer peripheral surfaces of the input shaft 24 and the clutch shaft 25. One end of the clutch spring 30 is inserted into a cam drum 26 that is integrated with the clutch shaft 25 and has a diameter larger than that of the clutch shaft, and the other end of the clutch spring 30 is on the outer peripheral surface of the input shaft 24. At the boundary end between the clutch shaft 25 and the input shaft 24, a rib 25a is formed at the end of the clutch shaft 25 so as to protrude toward the input shaft 24 in the outer diameter direction and the axial direction. A cutout portion 25b is formed in 25a (see FIG. 4). In addition, an inclined surface 25c that is inclined toward the notch 25b is formed on an end surface of the rib 25a adjacent to the notch 25b. When the bearing portion 24 a of the input shaft 24 is inserted into the clutch shaft 25, the rib 25 a is disposed across the outer peripheral surfaces of the clutch shaft 25 and the input shaft 24. Then, the portion of the clutch spring 30 that passes through the boundary line between the input shaft 24 and the clutch shaft 25 is forced to pass through only the portion of the notch 25b by the rib 25a, so that the boundary line is obliquely crossed. It has become. By taking the axial dimension of the rib 25a to some extent, the clutch spring 30 can be inclined more greatly with respect to the boundary line. Moreover, it guide | induces so that a boundary line may be crossed diagonally reliably and smoothly by the inclined surface 25c of the rib 25a.
[0013]
A guide groove 26 a is formed on the outer peripheral surface of the cam drum 26 integrated with the clutch shaft 25, and the guide groove 26 a is slid in the axial direction within a vertical groove 22 a formed on the inner peripheral surface of the case 22. The ball 28 that can move is slidable. The cam drum 26 and the ball 28 constitute a stopper mechanism. As shown in FIG. 3, the guide groove 26a is composed of an endless loop 26b extending endlessly in the circumferential direction of the cam drum 26, and a branch loop 26c branched from the endless loop 26b. A portion 26d and a second locking portion 26e are formed.
[0014]
Further, the input shaft of the speed reduction device 40 is connected to the cam drum 26 on the side opposite to the clutch shaft 25 so as to rotate integrally with the cam drum 26.
[0015]
The operation of the clutch device configured as described above will be described. First, when the winding shaft 10 is rotated in the descending direction of the shielding material, the input shaft 24 is rotated together, the clutch spring 30 is tightened, the input shaft 24 and the clutch shaft 25 are connected, and the cam drum 26 is also moved together. Rotate. At this time, the cam drum 26 rotates so that the ball 28 that cannot rotate with respect to the case 22 moves relative to the endless loop 26b of the guide groove 26a from the top to the bottom as indicated by the solid line arrow in FIG. The rotation of the cam drum 26 is transmitted to the brake device 40, and a brake is applied to the rotation. Therefore, the shielding member performs a lowering operation while being decelerated.
[0016]
Next, when the rotation of the winding shaft 10 changes to the rotation in the upward direction of the shielding material, the input shaft 24 rotates in the opposite direction, and the clutch shaft 25 rotates in the same direction as the input shaft 24. In the cam drum 26, the ball 28 moves relatively from the endless loop 26b to the branching loop 26c as indicated by the one-dot chain line arrow in FIG. 3, and reaches the first locking portion 26d. Therefore, after this, the cam drum 26 cannot rotate in that direction, so that the clutch spring 30 relaxes, the input shaft 24 and the clutch shaft 25 are disconnected, and the input shaft 24 is not connected to the clutch shaft 25. Idle. Therefore, the shielding material is separated from the brake device 40 and moves up without being decelerated.
[0017]
Next, when the rotational drive in the shielding material raising direction to the winding shaft 10 is stopped, the winding shaft 10 is rotated in the shielding material lowering direction due to its own weight, and when this rotation is input to the input shaft 24, The clutch spring 30 is tightened to connect the input shaft 24 and the clutch shaft 25. For this reason, the cam drum 26 also rotates together with the input shaft 24, and the ball 28 moves relatively. As shown by the two-dot chain arrow in FIG. 3, the first locking portion 26d to the second locking portion. 26e is reached. Thereafter, since the cam drum 26 cannot rotate in that direction, the rotation of the input shaft 24 and the winding shaft 10 connected by the clutch spring 30 is stopped. Thus, the shielding material stops at the height position.
[0018]
From this state, when the winding shaft 10 is rotated in the shielding material raising direction, this rotation is transmitted to the input shaft 24, the clutch shaft 25 and the cam drum 26, and the ball 28 is relatively moved from the branch loop 26c to the endless loop 26b. Then, the winding shaft 10 can be rotated in either the shielding material descending direction or the shielding material ascending direction.
[0019]
In the series of operations described above, the clutch spring 30 is relaxed when the winding shaft 10 is switched from rotation in the shielding material ascending direction to rotation in the shielding material descending direction, particularly as an operation immediately before the shielding material stops. From the state to the tightening state, a large torque is instantaneously applied, and the diameter of the clutch spring 30 tends to be reduced to a predetermined amount or more. However, because the clutch spring 30 crosses the boundary line diagonally by the rib 25a and the notch 25b at the boundary line portion between the input shaft 24 and the clutch shaft 25, the input shaft 24 and the clutch shaft 25 It is possible to prevent the clutch spring from biting into the boundary line between the two.
[0020]
Thus, by inclining the portion of the clutch spring 30 that passes through the boundary line between the input shaft 24 and the clutch shaft 25, it is possible to prevent the clutch spring 30 from being damaged with a simple configuration. In order to pass the boundary line obliquely, it is conceivable to use a coil spring having a large pitch and a large lead angle by partially changing the pitch of the clutch spring 30 itself. However, in this embodiment, it is always possible to forcibly force the coil spring of the portion that passes through the boundary line obliquely. Further, as a forced tilting means for forcibly passing the clutch spring 30, it is constituted by a rib 25 a and a notch 25 b provided integrally with the clutch shaft 25, so that the number of parts can be increased with a simple configuration. Can be implemented.
[0021]
In the above embodiment, the input shaft 24 and the clutch shaft 25 are taken as an example of the driving side shaft and the non-driving side shaft. However, the present invention is not limited to this, and any two shafts that are connected and disconnected are used. Needless to say, it can be applied. For example, in this example, the input shaft 24 and the clutch shaft 25 are connected when the shielding material is lowered, and the input shaft 24 and the clutch shaft 25 are disconnected when the shielding material is raised. The reverse may be possible, and the two shafts may be connected when the shielding material is raised, and the two shafts may be disconnected when the shielding material is lowered.
[0022]
In this embodiment, the rib and the notch are provided on the clutch shaft 25. However, it is also possible to provide them on the input shaft 24 or both the input shaft 24 and the clutch shaft 25. Further, the means for forcibly passing the clutch spring 30 is not limited to the means using the ribs and the notches, and any means can be used.
[0023]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the clutch spring from biting into the joint between the two shafts constituting the clutch device without increasing the number of parts.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view illustrating a clutch device according to an embodiment of the present invention.
2 is an exploded perspective view of the clutch device of FIG. 1. FIG.
FIG. 3 is a development view of the cam drum of FIG. 1;
FIG. 4 is a view as seen from an end face of a clutch shaft.
[Explanation of symbols]
24 Input shaft (drive side shaft)
25 Clutch shaft (non-drive side shaft)
25a Rib (forced tilting means)
25b Notch (forced tilting means)
25c Inclined surface 30 Clutch spring

Claims (2)

A drive side shaft (24) and a non-drive side shaft (25) that are relatively rotatable and arranged concentrically along the axial direction, and a clutch that is wound around these two shafts (24, 25) A clutch device having a spring (30), and selectively switching between connection and disconnection of two shafts (24, 25) using tightening and relaxation of the clutch spring (30),
At least one of the drive side shaft (24) and the non-drive side shaft (25) has a portion of the clutch spring (30) passing through the boundary line between the drive side shaft (24) and the non-drive side shaft (25). Forced tilting means (25a, 25b) for forcibly tilting with respect to the boundary line is provided,
The forced tilting means (25a, 25b) is formed on a rib (25a) formed integrally with at least one boundary end of the drive side shaft (24) or the non-drive side shaft (25) and the rib (25a). It is a notch part (25b) formed, the rib (25a) is arranged so as to straddle the boundary line, and the part of the clutch spring (30) passes through the notch part (25b) of the rib (25a). A clutch device.   The rib (25a) is formed with an inclined surface (25c) adjacent to the notch (25b) and inclined with respect to the boundary line, and the inclined surface (25c) is a portion of the clutch spring (30). The clutch device according to claim 1, characterized in that the guide is guided toward the notch (25b).

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