JPH06280965A - Speed reduction mechanism - Google Patents

Abstract

PURPOSE:To provide a compact speed reducing mechanism at a low cost which can give any desired gear ratio. CONSTITUTION:A motor 40 is supported swingably at a supporting point 42, and male threads are formed at the surface of the motor shaft 41 or a shaft rotating in a single piece therewith, and a nut member 43 having female threads to mesh with the male threads is coupled with one end of an arm 44, while the other end thereof is coupled rigidly with an output shaft 45. Otherwise, the motor 40 is fixed to a fixation body, and a long hole is formed in the arm 44, and the nut member 43 is detained with this long hole with a play.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reduction gear mechanism which can be compactly constructed with a small number of parts, and is suitable for application to a flying vehicle such as a small rocket or a model airplane which is required to be installed in a narrow space. Regarding

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a trajectory of a flying vehicle such as a small rocket or a model airplane is corrected by a fin 2 (wing) attached to an outer wall of a flying vehicle (a small rocket for convenience in the figure). ) Is adjusted by the electric motor, but in order to obtain a sufficiently large steering force, it is necessary to reduce the rotation speed of the motor at a high reduction ratio (1/100 or more) and transmit it to the fin 2. is there. Further, since the main component 3 such as the propulsion unit is mounted inside the projectile, the reduction mechanism can be accommodated in the narrow space between the outer wall of the projectile 1 and the main component 3 without any hindrance. Is required.

FIG. 6 shows a first conventional example. In this example,
The spur gear 12 of the motor shaft 11 and the spur gear 14 of the first shaft 13 parallel to the motor shaft 11 are engaged with each other, and the first shaft 13 is orthogonal to the first shaft 13 via the bevel gear 15 of the first shaft 13. The rotary motion of the electric motor 18 is transmitted to the bevel gear 17 of the second shaft 16. Note that B _{1 to} B ₅ are bearings such as bearings.

FIG. 7 shows a second conventional example. In this example,
A worm gear 22 attached to the motor shaft 21 and a worm wheel 23 meshing with the worm gear 22 are provided, and an electric motor 24 is attached to a shaft 23 a of the worm wheel 23.
I am trying to convey the rotational movement of. Incidentally, 25 is a shaft connecting member, and 26 and 27 are bearings.

[0005]

However, in each of these conventional examples, the reduction ratio is determined by the relationship between the tooth profile of the gear and the number of teeth, and it is difficult to freely select the reduction ratio. In addition, there are many problems that gears have many meshing points, sufficient assembly accuracy (axis-to-axis accuracy) is required, and that the number of parts is large and the manufacturing cost is high. [Purpose] Therefore, an object of the present invention is to provide an inexpensive and compact reduction gear mechanism that can freely obtain a desired reduction gear ratio.

[0006]

As shown in FIG. 1, the principle of the present invention is that a motor 40 is swingably supported at a support point 42, and the surface of a motor shaft 41 of the motor 40 or the motor 40 is supported. A nut member 43 having a thread formed on the surface of a shaft body that rotates integrally with the shaft 41 and having a female thread that meshes with the male thread.
Is connected to one end of the arm 44, and the other end of the arm 44 is rigidly connected to a predetermined output shaft 45.

Alternatively, the motor is fixed to a fixed body, an elongated hole is formed in the arm, and the nut member is movably engaged with the elongated hole.

[0008]

In the present invention, the motor 40 is energized by energizing the motor 40.
When 1 is rotated forward and backward in the direction of arrow A, the nut member 41 moves in the direction of arrow B (the axial direction of the motor shaft 41) and the arm 44 swings in the direction of arrow C (to be exact, the axial length of the arm 44 is changed). The rotational motion is transmitted to the output shaft 45 as a turning motion performed as a radius). Here, the ratio of the rotation speed of the motor shaft 41 to the rotation speed of the output shaft 45, that is, the reduction ratio, is determined steplessly according to the pitch of the male screw (and female screw) and the length of the arm 44. Therefore, if, for example, a fin is attached to the output shaft 45, the rotational movement of the motor shaft 41 is decelerated and transmitted to the fin, and the fin angle can be changed with a sufficient driving force (see arrow D).

Further, since the motor shaft 41 and the motor 40 oscillate around the support point 42 (see arrow E), the inter-axis accuracy as in the first or second conventional example at the beginning becomes unnecessary,
Moreover, since the number of parts is smaller than that of the conventional example and the structure can be made compact, for example, it is possible to provide a suitable speed reducing mechanism by applying to a small rocket or the like, which is required to be installed in a narrow space, or a flying object of a model airplane. .

In FIG. 1, in order to absorb the change in the intersection angle between the axis of the arm 44 and the motor shaft 41, which is caused by the swing of the arm 44, the nut member 43 and the arm 44 are absorbed.
A joint is provided between one end of the arm 44, but this position is an example, and for example, the other end side of the arm 44 (that is, the output shaft 45
Side). The point is that it may be a position that can absorb the change in the intersection angle.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a conceptual configuration diagram showing a first embodiment of a reduction mechanism according to the present invention, which is an example applied to a fin (wing) drive unit of a flying vehicle of a small rocket, for example. The speed reduction mechanism is incorporated into a fin drive assembly (not shown) mounted inside the flying body together with other components, and this assembly has, for example, the same number as the number of fins around the cylindrical base portion. The speed reduction mechanism is assembled.

As shown in FIG. 2, the reduction mechanism includes a motor (for example, a servomotor) 60, a motor shaft 61 having a male thread, a nut member 62 having a female thread meshing with the male thread, and the nut member 62. The protrusion 6 on one end side
3a is provided with an arm 63 that is rotatably supported.
The main body portion 63b, which is the other end side of 3, is rotatably attached to the outer peripheral surface of the base portion of the fin drive assembly, for example.

An output shaft 65 is attached to the center of rotation of the body portion 63a of the arm 63, and a fin (not shown) is attached to the output shaft 65. Therefore, when the motor shaft 61 rotates forward and backward as indicated by arrow F, the nut member 62 moves in the vertical direction in the figure (direction of arrow G).
And the arm 63 rotates in the direction of arrow H to move the output shaft 6
The rotation angle of 5, that is, the angle of the fin will change.

Reference numeral 64 is a support point for swingably supporting the motor shaft 61 of the motor 60 on the base portion of a fin drive assembly (not shown). The support point 64 is the arm 6
This is for allowing the swinging motion of the motor shaft 61 and the motor 60 (refer to the arrow E in FIG. 1) that occurs during the turning of No. 3. Here, the reduction ratio of the reduction mechanism of FIG.
Male thread (or female thread of nut member 62) pitch P
And the length L of the arm 63 determines steplessly. The smaller P or the longer L, the higher the reduction ratio (for example, 1/100).
Above) is obtained.

Therefore, according to the above-described embodiments, a compact reduction gear mechanism capable of realizing a desired reduction gear ratio steplessly with at least a small number of parts such as the motor 60 including the motor shaft 61, the nut member 62 and the arm 63 is provided. Can be configured. Moreover, the meshing portion is the motor shaft 61 and the nut member 6
2 is limited to one position, and the swing of the motor shaft 61 and the motor 60 is allowed around the support point 64 and the inter-axis accuracy is not required. It is possible to provide a low-cost deceleration mechanism suitable for application to a flying object such as a model airplane.

In this embodiment, the screw is formed on the surface of the motor shaft 61, but the screw may be formed on another shaft body that rotates integrally with the motor shaft 61. Further, it is desirable to form one of the male screw and the female screw with a resin having a low friction coefficient (for example, Teflon or nylon). A non-lubricated speed reduction mechanism can be realized and maintenance-free.

In addition, the male and female screws are
A CME (trapezoidal) screw can realize a speed reduction mechanism with high load and high efficiency. Furthermore, if the elongated hole 63c for fixing the nut member 62 is formed in the arm 63 and the fixing position thereof is adjustable, the distance (L) between the output shaft 65 and the nut member 62 can be easily changed. This is preferable because the reduction ratio can be made variable.

FIG. 3 and FIG. 4 show a second reduction mechanism according to the present invention.
It is a conceptual block diagram which shows an Example. In FIG. 3, reference numeral 70 denotes a motor having a body fixed to a fixed body (for example, a base portion of a fin drive assembly) 71, 72 denotes a motor shaft having a screw formed on the surface, and 73 denotes a female screw screwed to a male screw of the motor shaft 72. And 74 is an arm that connects the nut member 73 and a predetermined output shaft (for example, fin shaft) P _F.

Here, an elongated hole 74a is formed along the longitudinal direction of the arm 74, and the nut member 73 is movably engaged with the elongated hole 74a. Note that P _S is the center point of the nut member 73 when the crossing angle between the arm 74 and the motor shaft 72 is 90 degrees, and P _E is when the crossing angle between the arm 74 and the motor shaft 72 is θ degrees (θ <90 degrees). Is the center point of the nut member 73.

In such a structure, when the motor shaft 72 rotates forward and backward in the direction A, the nut member 73 causes the motor shaft 7 to rotate.
As a result of moving in the axial direction of 2 (direction of arrow A) and swinging movement of the arm 74 in the direction of C, rotational torque is transmitted to the output shaft. In the present embodiment, the magnitude of this transmission torque is set to the arm 7
4 can always be kept constant regardless of the intersection angle between the motor shaft 72 and the motor shaft 72.

That is, the transmission torque T _S when the intersection angle is 90 degrees is given by the following equation. Where T _S = F _S × L _S, where F _{S is} the moving force of the nut member 73 (see FIG. 4) L _{S is} the length of the arm between P _{S and} P _F (see FIG. 4) The transmission torque T _{E at the} intersection angle θ (θ <90 degrees) is given by the following equation.

T _E = F _E × L _E, where F _E : component force of the moving force F _S of the nut member 73 (see FIG. 4).
F _E = F _S × cos θ L _E : Length of arm between P _{E and} P _F (see FIG. 4) L _E = L _S / cos θ Therefore, in the formula, the cos θ terms of F _E and L _E are mutually Since it is canceled out, the equation becomes the equation, and after all, the transmission torque is always kept constant regardless of the crossing angle (T _S = T
_E ) You can.

This forms a long hole 74a in the arm 74 and allows the nut member 7 to freely move in the long hole 74a.
3 is engaged, the nut member 73 moves the output shaft P _F according to the change in the intersection angle between the arm 74 and the motor shaft 72.
Arm length up is because changes (L _S ~L _E).

[0024]

According to the present invention, it is possible to provide an inexpensive and compact reduction gear mechanism which can freely obtain a desired reduction gear ratio, for example, for a flying vehicle such as a small rocket or a model airplane which is required to be mounted in a narrow space. A suitable reduction mechanism can be realized by applying it. Alternatively, if the motor is fixed to the fixed body and the elongated hole is formed in the arm, and the nut member is engaged with the elongated hole in a freely movable manner, the magnitude of the torque transmitted to the output shaft can be determined by the arm. It can be kept constant regardless of the intersection angle of the motor shafts.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a conceptual diagram of a reduction mechanism according to the first embodiment.

FIG. 3 is a conceptual diagram of a reduction mechanism according to a second embodiment.

FIG. 4 is an explanatory view of the operation of the speed reduction mechanism of the second embodiment.

FIG. 5 is a diagram showing how fins are mounted on a flying object such as a rocket.

FIG. 6 is a conceptual configuration diagram of a first conventional example.

FIG. 7 is a conceptual configuration diagram of a second conventional example.

[Explanation of symbols]

40, 60, 70: Motor 41, 61, 72: Motor shaft 42, 64: Support point 43, 62, 73: Nut member 44, 63, 74: Arm 45, 65, P _F : Output shaft 71: Fixed body 74a : Slot

Claims (2)

[Claims] 1. A shaft body which supports a motor (40) swingably at a support point (42) and which rotates integrally with the surface of the motor shaft (41) of the motor (40) or the motor shaft (41). A nut member (43) having a thread formed on the surface and having a female thread meshing with the male thread
Is connected to one end of the arm (44), and the other end of the arm (44) is connected to a predetermined output shaft (45).
A reduction mechanism characterized by being rigidly connected to. 2. The motor is fixed to a fixed body, an elongated hole is formed in the arm, and the nut member is movably engaged with the elongated hole.
The described reduction mechanism.