JPH0234501Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a ball clutch used for controlling the transmission of rotation in a switching device attached to an actuator for opening and closing a valve.

[Prior Art] For example, in various plants, firefighting equipment, etc., valve actuators that open and close valves using power from a motor or the like are widely used. However, the general actuator is
As shown in the figure, a worm wheel 2 is attached to the output shaft 1.
A worm 3 is meshed with the worm wheel 2, and the worm 3 is driven by a motor 4 to rotate the output shaft 1. The output shaft 1 is used to open and close a valve body (not shown) of a valve to be operated.

By the way, when this type of valve actuator is operated by remote control or automatic control, information regarding the set limit operating position of the valve actuator, that is, the preset limit position of the output shaft 1 (valve body). In some cases, it may be necessary to sequentially collect and provide feedback on whether or not the goal has been reached. Therefore, such a valve actuator is provided with a switching device 5 which is configured to switch the position limit switch and output a signal to that effect when the set limit operating position is reached.

As shown in FIG. 8, such a switching device 5 includes a worm 6 for detecting a position mounted on the output shaft 1, a worm wheel 7 meshing with the worm 6, and a worm wheel 7. a take-out shaft 8 that supports the take-out shaft 8; a deceleration mechanism 9 that detects the position of the output shaft 1 from the rotation of the take-out shaft 8 and outputs a driving force when the output shaft 1 reaches a set limit operating position; 9, a switch pusher 12 that rotates by the cam 11, a limit switch 13 that issues a signal when pressed by the switch pusher 12, and a speed reduction mechanism 9. a manual operating mechanism 14 configured to drive the cam 11 when the output shaft 1 reaches a set limit operating position;
A clutch mechanism 15 is known which disconnects the connection between the take-out shaft 8 and the speed reduction mechanism 9 at the time of input from the manual operation mechanism 14 to the speed reduction mechanism 9.

[Problems to be Solved by the Invention] However, the conventional clutch mechanism 15 is generally made up of a plurality of gears meshing together, and when the manual operation mechanism 14 is operated, the gears are disconnected to release the mesh. Then, the connection between the take-out shaft 8 and the speed reduction mechanism 9 is cut off. Therefore, this separation operation requires a complicated mechanism and is inconvenient in that it is not easy to operate. In order to solve this problem, it has been proposed to use a ball clutch as the clutch mechanism. If a ball clutch is used, connection is automatically made and disconnected, so it is easy to operate and has a simple structure. However, the conventional ball clutch has an engagement recess provided on one pitch circle and a ball provided in the engagement recess so as to be able to engage and disengage from the input side. This is designed to restrict the transmission of rotation to the output side. Therefore, when adjusting the speed reduction mechanism, if the ball is disengaged from the engagement recess and disconnected from the take-out shaft 8, when the output shaft 1 is activated, the ball rotates together with the take-out shaft 8 and engages again. Until the take-out shaft 8 engages with the recess, the take-out shaft 8 rotates idly and its rotation is not transmitted to the deceleration mechanism 9, so that the output shaft 1
position feedback is inaccurate. This idling increases as the pitch between the engagement recesses increases, so in order to reduce this idling, the pitch can be made smaller and the resolution improved. However, there is a limit to how small the pitch can be made due to restrictions on the size of the ball, and therefore there is a limit to how much the resolution can be increased, making it difficult to eliminate the inaccuracy of the feedback.

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned circumstances, and includes a ball clutch in which a plurality of pitch circles are arranged concentrically, and the engagement recesses of each pitch circle are arranged in a concentric manner. The ball is disposed in a circumferentially shifted position relative to the engagement recess of the pitch circle, and a plurality of balls are provided corresponding to each pitch circle.

[Function] With this type of device, if the ball or the pitch circle rotates in the circumferential direction when the engagement between the ball and the pitch circle is released, either ball will rotate with a slight rotation compared to the conventional one. can be engaged with any of the engagement recesses of the corresponding pitch circle to transmit rotation from the input side to the output side.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. Note that the same components as those shown in the description of the conventional example are given the same numbers and the description thereof will be omitted.

Embodiment 1 (FIGS. 1 to 4) A ball clutch 17 is provided as a clutch mechanism of the switching device 5 of the valve actuator. This ball clutch 17 includes two pitch circles 18 and 19, holes 21 and 22 that are engagement recesses provided in these pitch circles 18 and 19, respectively, and balls 23 that are detachably provided in these holes 21 and 22, respectively. , 24. The pitch circles 18 and 19 are provided concentrically on the side surface of the take-out shaft 8 side of a rotary disk 26 fixed to the shaft 25 on the deceleration mechanism 9 side. They are provided at 12 locations at 30° intervals, and on the inner pitch circle 19, 12 holes 22 are provided at 30° intervals in the circumferential direction, and are offset by 15° from each hole 21 in the circumferential direction.
It is set up separately. On the other hand, the balls 23 and 24 are
Ball holding member 27 fixed to the tip of the extraction shaft 8
It is held by a ball holding portion 27a which protrudes in the radial direction. That is, the ball holding portion 27a
Holes 28 and 29 are bored in a straight line in the radial direction, and a spring 31 inserted into the hole 28 urges the ball 23 toward the pitch circle 18 to engage one of the holes 21. , spring 3 inserted into hole 29
1 to move the ball 24 to the pitch circle 19.
It is biased towards the side. Since this ball 24 is offset by 15 degrees in the circumferential direction from the nearest hole 22, it does not engage with the hole 22 and is in sliding contact with the side surface of the rotating disk 26 (FIG. 2).

Next, the operation of this embodiment will be explained.

When the output shaft (valve body) 1 reaches a preset limit position, the motor 4 is stopped to stop driving the output shaft 1, and the manual operation mechanism 14 is operated to move the shaft 2.
5 to adjust the deceleration mechanism 9, and this deceleration mechanism 9
is set so that it outputs a driving force to rotate the cam 11 and cause the switch presser 12 to press the limit switch 13. At this time, since the output shaft 1 has stopped rotating, the worm wheel 7 and the take-out shaft 8 are also prohibited from rotating, and therefore the ball holding member 27 fixed to the tip of the take-out shaft 8 also does not rotate. On the other hand, the manual operation mechanism 14
When the shaft 25 is rotated, the rotating disk 26 fixed to the tip of the shaft 25 also rotates, so that the engagement between the ball 23 and the hole 21 is released due to this rotation, and the rotating disk 26 is rotated so that the rotating disk 26 is fixed to the tip of the shaft 25. Rotates relative to the holding member 27. When the output shaft 1 is driven again after adjusting the speed reduction mechanism 9, the worm wheel 7 and the take-out shaft 8 rotate, and the ball holding member 27 also rotates together. Along with this rotation, the balls 23 and 24 also rotate, and the corresponding holes 2
1 or 22, and this engagement transmits the rotation of the take-out shaft 8 to the deceleration mechanism 9 side via the rotating disk 26. At this time, since the holes 21 and 22 are provided 15 degrees apart in the circumferential direction, either of the balls 23, 24 and the holes 21, 22 are provided.
2, the ball holding member 27 is engaged with the ball holding member 27 within a rotation angle of 15 degrees. Therefore, the resolution is doubled compared to the conventional type with only one pitch circle, which requires the ball holding member 27 to rotate by a maximum of 30 degrees for engagement, and the position detection accuracy is increased accordingly. Therefore, the information that the output shaft 1 has reached the set limit operating position can be fed back more accurately.

Embodiment 2 (FIGS. 5 to 7) The ball clutch 41 is connected to the pitch circle 42,
43, 44, engagement recessed holes 45, 46, 47,
And balls 48, 49, 51, 52, 53, 5
4. Pituchi Circle 4
2, 43, and 44 are provided concentrically on the rotating disk 55, and holes 45, 46, and 47 are provided in each pitch circle 42, 43, and 44, and holes 45, 46, and 47 are spaced 30 degrees apart from the holes in the other pitch circles by 10 degrees. They are installed in 12 locations at ゜ intervals. On the other hand, the ball holding member 56 has two protrusions 56a and 56b located 170 degrees apart from each other around the axis, and holes 57 and 5.
8, 59 to the protrusion 56a, holes 61, 62, 63
are provided in the protruding portion 56b in a straight line in the radial direction, and a spring 6 is provided in each of the holes 57 to 63.
4 is loaded, and the balls 48, 49, 51, 52, 53, 54 are urged by the spring 64 toward the corresponding pitch circle.
In the state shown in FIG. 5, the ball 48 provided on the protrusion 56a and the ball 5 provided on the protrusion 56b.
4 are engaged with one of the corresponding holes 45, 47, respectively. In addition, in FIG. 5, for convenience of explanation, a cut surface along the center line l of the ball holding member 56 is shown.

If it is like this, the ball holding member 56
If the ball is rotated by a maximum of 10 degrees, any ball will engage with any hole, so the resolution is higher than that shown in the first embodiment. Moreover, since they engage at two places, rotation can be transmitted more reliably.

Note that the present invention is of course not limited to the above embodiments, and the number of pitch circles may be two or three.
The number is not limited to four, and may be four or more.

Also, the spacing between the engagement recesses on each pitch circle is
The pitch circle is not limited to 30 degrees, and the distance from other pitch circle holes is not limited to 15 degrees or 10 degrees.

Further, the engagement recess is not limited to a hole, and may be, for example, a trough of a gear tooth.

[Effects of the Invention] As explained above, the present invention can provide a ball clutch that has a simple structure, good operability, and high resolution, allowing more accurate position detection.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention, FIG. 1 is a schematic explanatory diagram showing the state of use, FIG. 2 is a sectional view, FIG. 3 is a sectional view taken along the line - in FIG. FIG. 4 is a sectional view taken along the - line in FIG. 2. Figures 5 to 7 show other embodiments of the present invention;
The figure is a cross-sectional view, FIG. 6 is a cross-sectional view taken along the line -- in FIG. 5, and FIG. 7 is a cross-sectional view taken along the line -- in FIG. FIG. 8 is a diagram corresponding to FIG. 1 showing a conventional example. 17, 41...Ball clutch, 18, 19,
42, 43, 44... Pitch Circle, 21, 2
2, 45, 46, 47...Engagement recess (hole), 23,
24, 48, 49, 51, 52, 53, 54...
ball.

Claims (1)

[Scope of utility model registration request] It has an engagement recess provided on the pitch circle and a ball removably provided in the engagement recess, and the transmission of rotation from the input side to the output side is regulated by the engagement and removal of the engagement recess and the ball. In the ball clutch, a plurality of the pitch circles are provided concentrically, and the engagement recess of each pitch circle is arranged with a circumferentially shifted position from the engagement recess of the other pitch circle, and the ball is This ball clutch is characterized by having a plurality of ball clutches each corresponding to each pitch circle.