JPH0689826B2 - Clutch device and speed reducer including the clutch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a clutch device in a power transmission mechanism, which is capable of exhibiting an intermittent function automatically and in both forward and reverse directions in accordance with a rotational force transmission direction. And a speed reducer including this clutch device.

[Conventional technology]

There are crown clutches, friction clutches, electromagnetic clutches, and the like as clutch devices that transmit or release rotational force in both the forward and reverse directions, but all require external power to connect or disconnect.

Further, an automatic meshing type, for example, a centrifugal clutch device operates only in one rotation direction.

Therefore, as far as the inventor knows, a clutch device that automatically operates in both forward and reverse directions without requiring external power has not been put to practical use.

[Problems to be Solved by the Invention]

In the case of driving a large-sized valve device or the like by an electric motor, it is customary to manually operate in preparation for a failure of the electric motor.

In this way, when the electric power of two systems of the electric motor and the manual force is connected in parallel to one load, one power,
For example, when the electric motor is coupled to the load, the other hand-powered handwheel must be released to the load.

That is, when the powers of the two systems are directly connected to the load, when either one is driven, the transmission system of the other power is
If a transmission system having a large reduction ratio between each power and the load (valve device) is present as a load for the driving force, the undriven power system becomes a load for the driven power system.

In particular, when the transmission system having a large reduction ratio is a worm gear, direct determination of the two power systems is impossible.

In order to solve such problems, between each power and load,
Although a clutch device is used, the conventional clutch device requires another power for switching operation.

Further, recent valve devices are controlled by remote control, and the vicinity of the valve device is often unmanned. Therefore, in case of failure of the electric motor, a second motor is installed in addition to the manual operation means. .

The second motor may be an electric motor, but an electric motor, a hydraulic motor, or the like having a different power generation method is often used.

In such a case, for one load valve device, 3
The power of the system will be combined, and the clutch device will
It will be installed for each power system.

In the case of a remote device, since the switching control of the clutch device is also remote control, if the number of clutches is large, the control becomes complicated, the number of control signals increases, and the switching operation is performed for each clutch device. Therefore, an electric switching operation actuator for generating power is required.

According to the present invention, the rotational force on the load side is not transmitted to the drive side, and only the rotational force on the drive side is automatically coupled with rotation of the drive side in both forward and reverse directions and transmitted to the load side. By providing an automatic switching type clutch device, the above problem is solved, and by providing a speed reducer including the clutch device, a plurality of drive systems are directly connected to a load, and It is designed to solve the problem.

[Means for Solving the Problems]

In the present invention, a non-circular shaft having a maximum radius (R ₂ ) and a minimum radius (R ₄ ) provided at a proper position on the load-side rotating shaft is provided with an annular ring driven by appropriate power as a non-circular shaft. It fits coaxially,
Between this non-circular axis and the ring, the concave bottom has the maximum radius (R ₁ ), and on both sides of the bottom, the minimum radius of the non-circular axis (R ₄ ) and the diameter of the engaging slider (D ₁ ) described later. Than the sum of the above, a recess provided with an engaging projection having a minimum radius (R ₃ ) protruding in the axial center (O) direction by a desired meshing allowance (Δt) is provided in the annular ring, and the circumference of the non-circular shaft is An engaging slider rolling on the surface and having a diameter (D ₁ ) slightly smaller than the dimension of the maximum radius of the recessed bottom (R ₁ ) minus the maximum radius of the non-circular shaft (R ₂ ),
Rotation that fits loosely in the recess and is rotatable with respect to the non-circular shaft and the annular ring, and is provided with rotational resistance between appropriate base members that are stationary with respect to the non-circular shaft and the annular ring. A groove, which is slightly wider than the diameter (D ₁ ) of the engaging slider, is provided in the body in parallel with the axial direction, and the engaging slider is loosely fitted in the groove so that it cannot move in the rotational direction and has a diameter Movably in the direction, the engaging slider is supported on the rotating body, and when the engaging slider comes into contact with the smallest diameter portion of the non-circular shaft when the ring is rotated by power, the engaging slider is engaged. The synthetic slider meshes between the non-circular shaft and the engaging convex portion to restrain the relative rotation between the circular ring and the non-circular shaft,
A clutch device that solves the above-described problems is provided, and a shaft portion of a final stage gear of a reduction gear having a large reduction ratio has a larger diameter than a maximum diameter portion of a non-circular shaft of an output shaft of the clutch device with respect to a rotation axis. A hole having a diameter is provided coaxially with the rotation shaft, the gear itself serves as an annular ring in the clutch device, and an engaging slider is interposed between the annular ring and the non-circular shaft, and the engaging slider is A speed reducer that solves the same problem is provided by slidingly supporting the rotating body in an appropriate position of the casing of the speed reducer so as to obtain an appropriate rotational friction resistance.

[Work]

When the input rotary shaft is driven by a drive source such as a motor, the input shaft is automatically coupled with the output shaft.

Further, when the output shaft is driven by another drive system while the input shaft is not driven, the output shaft is automatically separated from the input shaft and idles.

〔Example〕

1 to 3 show an embodiment of the clutch device according to the present invention.

(1) is an input shaft directly connected to a drive source such as a motor,
(2) is an output shaft directly connected to the load, and (3) is a base member pivotally supporting the input shaft (1) and the output shaft (2).

Outer circumference (5) of the expanded shaft end (4) of the input shaft (1)
Are pivotally supported on the base member (3) via bearings (6).

A circular bottomed hole (8) is provided in the shaft center portion of the shaft end portion (4) on the side of the tip surface (7), and the tip end of the shaft end portion (4) becomes a ring (9). There is.

The input shaft (1) and the output shaft (2) are coaxial, the shaft end (4) of (1) and the shaft end (10) of the output (2) are butted against each other, and the shaft end of the output (2) is The part (10) projects into the bottomed hole (8).

The shaft end (10) of the output shaft (2) has four cutout surfaces (11).
However, it is a non-circular shaft (12) having a substantially square cross section, which is provided at equal intervals, leaving some peripheral surface parts, and whose corners are arcuate.

A part where both shaft ends (4) and (10) are overlapped with each other, that is, the inner peripheral surface (14) of the ring (9) and the non-circular shaft (12).
A sufficient gap (15) is provided between the outer peripheral surface (13) and the outer peripheral surface (13).

In the place facing 180 ° in the gap (15),
Two cylindrical engaging sliders (16) are provided.

Further, in the gap (15), the engagement slider (16) is loosely held in the cut groove (17) so as not to escape in the rotational direction, and the small diameter sleeve (19) of the rotating body (18). But it is loosely fitted.

The rotating body (18) includes the small diameter sleeve (19) on the input shaft (1) side and the large diameter sleeve (20) having a larger diameter than the small diameter sleeve (19) on the output shaft (2) side. It is a stepped sleeve provided.

The outer circumference (21) of the large-diameter sleeve (20) has a base member (3).
Is loosely fitted in the shaft hole (22) of the
By fitting the ring (23), an appropriate frictional resistance is given to the base member (3). A bearing (25) is provided between the inner circumference (24) of the large-diameter sleeve (20) and the outer circumference of the output shaft (2), and the output shaft (2) and the rotating body (18) are opposed to each other. It is pivotal.

Thus, the rotating body (18) is rotatable with respect to the input shaft (1), the output shaft (2) and the base member (3), and has a slight rotational resistance with respect to the base member (3). Has been given.

The engaging slider (16) has its axis aligned with the input / output shafts (1) and (2).
It is parallel to the axis of and can roll freely on the peripheral surface of the non-circular shaft (12).

An annular ring (9) is provided on both sides of the engaging slide (16) in the rolling direction.
A columnar pin (26) protruding inward from the inner peripheral surface (14) and having its axis parallel to the engaging slider (16) is fitted to and supported by.

The spacing between the cylindrical pins (26) (26) on both sides of the engagement slider (16) is determined by the distance between the engagement sliders (16) located between them.
It is desirable that it does not move significantly in the direction of rotation.

The radius (R ₁ ) of the inner peripheral surface (14) of the ring (9) is the sum of the maximum radius (R ₂ ) of the non-circular shaft (12) and the diameter (D ₁ ) of the engaging slider (16). It is slightly larger than (R ₂ + D ₁ ).

Further, the radius (R ₃ ) of the rotation locus of the portion from the rotation center (O) of the peripheral surface of the cylindrical pin (26) is the minimum radius (R ₄ ) of the non-circular shaft (12) and the engaging groove (16). Sum of diameters (D ₂ ) (R ₅ = R ₄ +
It is specified to be slightly smaller than D ₁ ).

The diameter (D ₂ ) of the cylindrical pin (26) is approximately the same as the diameter (D ₁ ) of the engaging slider (16).

Further, the engaging slider (16) has cylindrical pins (26) on both sides thereof,
Between the inner peripheral surface (14) of the circular ring (9) between them, the peripheral surface of the non-circular shaft (12) rolls into the recess (27) formed in the inner peripheral surface of the circular ring (9). It is free and fits into the recess (27) so that it cannot escape.

In other words, the recess (27) formed by the inner peripheral surface (14) and the two columnar pins (26) has the bottom of the recess formed by the inner peripheral surface (14) as the maximum radius (R ₁ ), On both sides of
The cylindrical pin (26) projects in the axial center (O) direction by the required meshing allowance (Δt) than the sum of the minimum radius (R ₄ ) of the non-circular shaft and the diameter (D ₁ ) of the engaging slider described later. The engaging protrusion having the minimum radius (R ₃ ) is provided, and the recess (27) is provided in the ring (9).

Further, inside the recess (27), rolling slightly on the peripheral surface of the non-circular shaft, and slightly smaller than the size obtained by subtracting the maximum radius of the non-circular shaft (R ₂ ) from the maximum radius of the recess bottom (R ₁ ). An engagement slider (16) having a small diameter (D ₁ ) is loosely fitted.

Groove (1) of small diameter sleeve (19) in rotating body (18)
7) loosely sandwiches the engaging slider (16) from both sides in the rotational direction, whereby the engaging slider (16) is movable in the direction orthogonal to the axis and the rotating body (18). It can be rotated around the axis along with the rotation of.

FIG. 2 shows a state in which the input shaft (1) and the output shaft (2) are not connected. Even if the output shaft (2) rotates in this state, the rotational force is the same as the input shaft (1). Does not reach.

That is, the engagement slider (16) is located in the center of the recess (27) between the cylindrical pins (26). Even if the maximum radius (R ₂ ) and the minimum radius (R ₄ ) of the non-circular shaft (12) come into contact with the engaging slider (16) by the rotation of the output shaft (2), the engaging slider (16) Is rolling on the peripheral surface of the non-circular shaft (12) in the kerf (17) of the rotating body (18), while idling, and only swinging in the direction orthogonal to the axis. It never meshes with (9).

When the input shaft (1) rotates in the clockwise direction from the state shown in FIG. 2, the cylindrical pin (26) at the rear in the rotation direction is engaged with the engaging slider (16).
Press to roll it in the direction of rotation.

The rolling of the engaging slide (16) causes the rotating body (18) to rotate, and friction resistance is imparted between the rotating body (18) and the base member (3). Pin (26)
A resistance corresponding to the frictional resistance is generated at the abutting portion of the engaging slider (16).

As a result, the engagement slider (16) rolls along the peripheral surface of the non-circular shaft (12) while pressing the peripheral surface of the non-circular shaft (12), and the radius of the peripheral surface of the non-circular shaft (12) is At the place where the engagement slider (16) gradually decreases in the rolling direction, the engagement slider (16) moves along the circumferential surface of the cylindrical pin (26) with respect to the ring (9). Move in the delay direction.

When the engaging slider (16) contacts the minimum radius (R ₄ ) of the non-circular shaft (12), the radius of the non-circular shaft (12) gradually increases before that and the engaging slider Since the (16) moves in the forward direction, the cylindrical pin (26) and the non-circular shaft (12) press the engaging slider (16), and the circular ring (9) and the non-circular shaft (12) are integrated. After the rotation, the input shaft (1) and the output shaft (2) are brought into a coupled state as shown in FIG.

In this coupled state, when the output shaft (2) is driven and rotated in the same direction as the rotational direction of the input shaft (1) when the coupling occurs, the coupling is released and the output shaft (2) idles. .

That is, when the input shaft (1) is stopped after driving from the input shaft (1) side to the output shaft (2) side, the output shaft (2) is moved in the same direction as the direction in which it was driven. When it is rotated to, the bond is released.

On the other hand, in the counterclockwise rotation of the input shaft (1) as well, the input shaft (1) and the output shaft (2) can be similarly coupled, and the input shaft (1) can revolve its rotational force in the normal and reverse directions. It can be transmitted to the output shaft (2) in both directions.

Engaging slide (16) between the cylindrical pin (26) and the non-circular shaft (12)
The degree of meshing (difficulty in escape), ease of meshing, meshing strength, etc. when the is pressed and restrained are the diameter of the engaging slider (16) (D ₁ ) and the diameter of the cylindrical pin (26) (D ₂ ) Non-circular shafts (12)
Maximum radius (R ₂ ) and minimum radius (R ₄ ) of, and cylindrical pin (2
It is determined by the values of the radius (R ₃ ) of the rotation locus of the part of the peripheral surface of 6) from the center of rotation (O) and the frictional resistance of the rotating body (18).

If the frictional resistance of the rotating body (18) is large, the meshing will be easy, and the engagement slider (16) will not easily escape in the direction of advance of the rotation of the ring (9).

The dimension (R ₄ + D ₁ ) −R ₃ that prevents the engaging slider (16) from coming out of the recess (27) of the ring (9) is the meshing allowance (Δt). The smaller (Δt) is,
Between the cylindrical pin (26) and the engagement slider (16), which are in contact with each other in an arcuate surface, the force in the advance direction (relief direction) generated in the engagement slider (16) at the time of engagement is reduced, and the engagement is achieved. The degree improves. However, due to the wear and elastic deformation of the columnar pin (26), the engaging slider (16) easily comes out of the recess (27) in the delay direction, and the meshing strength decreases.

The larger the diameter (D ₁ ) of the engaging slider (16), that is, the curvature of the rim of the recess (27), the larger the allowance for engagement, and the better the degree of meshing and the easier meshing. , An engaging slider (16) that relatively rotationally moves in a delay direction with respect to the ring (9) from the non-meshing neutral position to the meshing position.
Will move a lot.

Considering the above, depending on the load torque and purpose of use,
The relevant dimensions are defined.

[Other Examples]

4 to 7 show an embodiment in which the cross-sectional shape of the non-circular shaft (12) is different, and the number of engaging sliders (16) and the recesses (27) of the ring (9) are shown. The position etc. shows the case most suitable for the cross-sectional shape of the non-circular shaft (12), and the other parts are the first
It is similar to that in the figure.

FIG. 4 shows a non-circular shaft (12a) provided with a notch surface (28) of an appropriate depth at one location on the peripheral surface of a round shaft. A child (16) and a recess (27) are provided.

In Fig. 5, the peripheral surface (13) of the non-circular shaft (12b) is a regular hexagon, and the recesses (27) of the ring (9) are provided at three positions at 120 ° intervals. Engagement sliders (16) are fitted in each.

In this embodiment, the non-circular shaft (12b) and the ring (9) are
When engaged through the individual engaging slides (16), the force for gripping the non-circular shaft (12) acts centripetally from three directions at an equal angle of 120 °, so There is little eccentricity in the coupling of the output shaft (2), and good rotation can be transmitted.

FIG. 6 shows the non-circular axis (12c) as an elliptic axis, and the other parts are the same as in FIG.

FIG. 7 shows a case where the non-circular shaft (12d) is an eccentric shaft, which is substantially the same as that of FIG.

That is, although the cross section of the shaft on which the engagement slider (16) rolls is a perfect circle, the points corresponding to the maximum radius (R ₂ ) and the minimum radius (R ₄ ) with respect to the rotation center (O) are We have one each.

As can be seen from this example, the non-circularity of the non-circular shaft (12) in the present invention is considered with respect to the center of rotation (O), and the non-circular shaft (12) is The shaft is provided with at least one small-diameter portion on the rolling peripheral surface, and a peripheral surface between the small-diameter portion and the large-diameter portion in which the diameter gradually and continuously changes relatively gradually.

Further, the portion of maximum radius (R ₂ ) shown in FIGS. 1 and 4 has an arc shape centered on the center of rotation (O), and such arc locations are meshed in terms of arc length and presence / absence. Since it is not directly involved, the regular hexagonal non-circular shaft (12b) shown in Fig. 5
Even if similar arcuate portions are provided at the corners and other polygonal corners, there is no hindrance to the meshing.

8 and 9 show the rotating body (18a) and the engaging slider (16a).
2 shows another embodiment in which the concave portion (27a) is different from the embodiment shown in FIG. 1, and the other portions are almost the same as the embodiment shown in FIG.

The engaging slider (16a) in this embodiment is a sphere,
The rotating body (18a) is a disk (20) obtained by shortening the sleeve portion of the large-diameter sleeve (20) of the rotating body (18) shown in FIG.
a).

The spherical engagement slider (16a) is attached to the small diameter sleeve (19a)
The portions projecting from the through holes (17a) provided facing each other by 0 ° are fitted into the recesses (27a) provided in the inner peripheral surface (14a) of the ring (9a).

The inner peripheral surface (14a) of the circular ring (9a) has a radius equal to the radius (R ₃ ) of the innermost rotation locus of the cylindrical pin (26),
The inner peripheral surface (14a) is provided with a groove (29) extending in the axial direction 180
Cut in two places at an interval of ゜ and dent the groove (29) (27a)
There is.

The rim of the recess in the rotational direction (27a) (30) is are chamfered in the same curvature as the radius (D _2/2) of the columnar pin (26).

The output shaft (2) has a bearing (25
It is directly pivoted via a) and the disk (20a) of the rotating body (18a).
(a) is in contact with the wall surface (3a) of the base member (3) through the friction sliding body (23a), and rotation resistance is imparted.

In this embodiment, both the input shaft (1) and the output shaft (2) are independently pivoted on the base member (3) and the cylindrical pin (2)
6) is not used.

However, when the cylindrical pin (26) is used as in the above-mentioned embodiment, there is an advantage that the cylindrical pin (26) alone can be hardened to increase the meshing strength or to resist abrasion. When the recess (27a) is formed by the groove (29) as in this embodiment, the radius (R ₂ ) of the inner peripheral surface (14a) itself is maintained even if the rim (30) is slightly worn. Since the meshing allowance (Δt) is not formed, there is an advantage that the engaging slider (16a) does not escape from the recess (27a).

FIG. 10 shows an embodiment of a speed reducer including the above-mentioned clutch device.

(A) is the same clutch device as in FIG. 1, (32) is a worm wheel corresponding to the input shaft (1) in the same figure, (33)
Is a worm that serves as an input shaft of the speed reducer, and (34) is a casing of the speed reducer corresponding to the base member (3) in the figure.

A bottomed hole (36) that forms an inner peripheral surface (35) corresponding to the inner peripheral surface (14) of the ring (9) is provided on one side surface of the rotating shaft center portion of the worm wheel (32). , And on the other side,
The output shaft (37) is provided as usual.

The output shaft (37) directly connected to the worm wheel (32) is pivotally supported by the casing (34) via the bearing (38).

The non-circular shaft (12) at one end of the output shaft (2) of the clutch device (A) is loosely fitted in the bottomed hole (36) of the worm wheel (32), and the other of the output shaft (2) The end projects to the outside of the casing (34). A cylindrical pin (26) is provided on the inner peripheral surface (35) of the bottomed hole (36), and the outer circumference of the large diameter sleeve (20) of the rotating body (18) is connected via an O-ring (23). It is in contact with the shaft hole (39) of the casing (34).

Since the structure of the clutch device (A) is the same as that of FIG. 1, the same reference numerals are given to the clutch device (A) and description thereof will be omitted.

In the speed reducer according to the present invention, the output that cannot be driven in the reverse direction is obtained from the output shaft (37) directly connected to the worm wheel (32), and the output shaft (2) via the clutch device (A) is used. , Output that can be driven in the reverse direction can be obtained.

As a result, the speed reducer enables the output shaft (2) on the clutch device (A) side to be directly assembled to the load shaft on an appropriate machine, and more than one speed reducer can be attached to one load on the load side. Can be assembled directly.

〔The invention's effect〕

The clutch device according to the present invention can exhibit the above effects.

(1) When the input shaft is driven, the input shaft and the output shaft are automatically coupled, so that separate power for switching is unnecessary.

(2) The load can be reciprocally driven and forward / reverse driven by being automatically coupled to both forward and reverse rotations of the input shaft.

(3) Rotation from the output shaft side is not transmitted to the input shaft side.

(4) According to the above (1) to (3), a plurality of drive sources are
It is possible to provide one load in parallel and directly connected to the load side.

Further, the speed reducer equipped with the clutch device described above, even when directly connected to the load shaft when assembled on a machine, does not require disconnection or disassembly of the speed reducer during maintenance and inspection on the load shaft side. Can be freely rotated to perform repairs and inspections around the load axis, making maintenance and repair work very easy.

[Brief description of drawings]

1 to 3 show an embodiment of the clutch device according to the present invention. FIG. 1 is a side view of a central longitudinal section of the clutch device, and FIG. 2 is a case where an input shaft and an output shaft are engaged with each other. FIG. 3 is a sectional view taken along the line AA in FIG. 1 showing a state in which the input shaft and the output shaft are not coupled,
Sectional views similar to FIG. 2, and FIGS. 4 to 7 are sectional views similar to the line AA in FIG. 1, showing various embodiments of non-circular shafts, respectively, and FIGS. 8 and 9. FIG. 8 shows another embodiment of the present invention. FIG. 8 is a side view of a central longitudinal section, FIG. 9 is a vertical sectional view taken along the line BB in FIG. 8, and FIG. It is a central longitudinal section side view showing an example of a speed reducer provided with such a clutch device. (1) Input shaft, (2) Output shaft (3) Base member, (3a) Wall surface (4) Shaft end, (5) Outer circumference (6) Bearing, (7) Tip surface (8) Bottomed hole, ( 9) (9a) Annular ring (10) Shaft end, (11) Notched surface (12) (12a) (12b) (12c) (12d) Non-circular shaft (13) Outer circumference, (14) Circumferential surface (15) ) Interval, (16) (16a) Engagement slider (17) Groove, (17a) Through hole (18) (18a) Rotating body, (19) Small diameter sleeve (20) Large diameter sleeve, (20a) Disc ( 22) Shaft hole, (23) O-ring (23a) Friction slide, (24) Inner circumference (25) (25a) Bearing, (26) Cylindrical pin (27) (27a) Recess, (28) Notch surface (29) ) Groove, (30) Edge portion (32) Worm wheel (33) Worm wheel, (34) Casing (35) Inner surface, (36) Bottom hole (37) Output shaft, (38) Bearing (O) Center of rotation, (Δt) meshing allowance (A) Clutch device

Claims (10)

[Claims] 1. A non-circular shaft having a maximum radius (R ₂ ) and a minimum radius (R ₄ ) provided in a proper position on a load-side rotating shaft, and an annular ring driven by appropriate power as a non-circular shaft. Between the non-circular shaft and the torus, the recessed bottom portion has a maximum radius (R ₁ ) between the non-circular shaft and the circular ring, and the minimum radius (R) of the non-circular shaft and the engagement slider described later are provided on both sides of the bottom portion. The ring is provided with a recess having an engaging projection having a minimum radius (R ₃ ) that is projected in the axial center (O) direction by a desired meshing allowance (Δt) rather than the sum of the diameters (D ₁ ), and Engaging slider that rolls on the peripheral surface of the non-circular shaft and has a diameter (D ₁ ) slightly smaller than the maximum radius of the recess bottom (R ₁ ) minus the maximum radius of the non-circular shaft (R ₂ ). To
Rotation that fits loosely in the recess and is rotatable with respect to the non-circular shaft and the annular ring, and is provided with rotational resistance between appropriate base members that are stationary with respect to the non-circular shaft and the annular ring. A groove, which is slightly wider than the diameter (D ₁ ) of the engaging slider, is provided in the body in parallel with the axial direction, and the engaging slider is loosely fitted in the groove so that it cannot move in the rotation direction and has a diameter of Movably in a direction, the engaging slider is supported by the rotating body, and when the engaging slider comes into contact with the smallest diameter portion of the non-circular shaft when the ring is rotated by power, the engaging slider is engaged. The clutch is a clutch device that meshes between the non-circular shaft and the engaging projection to restrain relative rotation between the circular ring and the non-circular shaft. 2. The non-circular shaft has at least 1 on the peripheral surface of the round shaft.
The clutch device according to claim 1, wherein the clutch device is provided with notched surfaces at more than one place. 3. The clutch device according to claim 1, wherein the non-circular shaft has a polygonal cross section. 4. The clutch device according to claim 1, wherein the non-circular shaft has an elliptical cross section. 5. The clutch device according to claim 1, wherein the non-circular shaft is eccentric with respect to the center of rotation. 6. The clutch device according to claim 1, wherein the engaging slider is a cylindrical body. 7. The clutch device according to claim 1, wherein the engagement slider is a sphere. 8. The clutch device according to claim 1, wherein the recess of the ring is formed between the two cylindrical pins. 9. The clutch device according to claim 1, wherein the recess of the ring is formed by providing a groove on the inner circumference of the ring. 10. A hole having a diameter larger than a maximum diameter portion with respect to a rotation axis of a non-circular shaft of an output shaft in a clutch device is coaxial with the rotation shaft in a shaft center portion of a final stage gear of a reduction gear having a large reduction ratio. , The gear itself serves as an annular ring in the clutch device, and an engaging slider is interposed between the annular ring and the non-circular shaft, and a rotating body supporting the engaging slider is provided in the speed reducer. The speed reducer comprising the clutch device according to claim 1, wherein the casing is slidably contacted at an appropriate position so as to obtain an appropriate rotational friction resistance.