JPH0392653A - Gear - Google Patents

Abstract

PURPOSE:To obtain a large reduction gear ratio with a compact and one-stage gear by forming a first waveform having the constant pitch on the peripheral surface of a first member made of a spiral rod turning around of a rotary shaft along the rotary shaft, and engaging the first waveform with a second waveform having the different pitch and formed on a second member. CONSTITUTION:When a first member is rotated, a first waveform 8 is rotated along the spiral to be waved to the axial direction, and an engagement position with a second wave form 10 thereof is moved along the axial direction. Since both the waveform 8, 10 have different pitches from each other, positions of a wave crest 13 and a wave trough 14 to be engaged with each other at next time of a wave crest 11 of the first waveform 8 and a wave trough 12 of the second waveform 10 engaged with each other at the present do not correspond with each other. Consequently, when the first member 1 is rotated and the crest of the first waveform in engagement is drawn from the corresponding trough of the second waveform, the next crest of the first waveform contacts to the side surface of the next trough of the second waveform and pushes the side surface to the axial direction to be engaged gradually, and the second member 2 is driven to the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a novel transmission mechanism that converts rotational motion of a human-powered member into linear motion of an output member.

<Prior art> As this type of transmission mechanism, a so-called pole screw structure, in which a pole nut is screwed through a large number of steel balls to a rod with thread grooves carved on the outer circumferential surface, is conventionally known. . In this case, the rod moves in the axial direction by one lead of the thread groove for one rotation of the pole nut, and the feed amount is always determined by the lead of the thread groove, making it possible to obtain a relatively large reduction ratio.

By the way, in a power seat system for a vehicle that uses an electric motor to drive the seat and adjust its position, it converts the rotary motion of the motor into linear motion and has a very large reduction ratio, so it usually uses multiple reducers. You also need to combine the steps. For this reason, the entire device becomes complicated and large, which increases the manufacturing cost and causes disadvantages such as a large mechanical loss of driving torque.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to provide a transmission mechanism that has a novel structure for converting rotational motion into linear motion, is compact, and is capable of obtaining a large reduction ratio in one step. Our goal is to provide the following.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, the above object is to provide a transmission mechanism for transmitting power between a first member that rotates and a second member that moves linearly. wherein the first portion is fixed in the axial direction and has a first waveform with a certain constant pitch arranged along a spiral that rotates along the axial direction about the rotation axis thereof. , the second member has a second waveform with a certain constant pitch arranged along the direction of movement of the second member, and the first waveform and the second waveform are different from each other of the waves of the first waveform. number is 3
To provide a transmission mechanism, wherein the spirals turning 60 degrees have pitches that are different from each other so that the number of waves is one less than the number of waves of the corresponding second waveform, and the spirals are engaged with each other so as to transmit power. achieved by.

<Operation> In this way, when the first member is rotated, the first waveform rotates along the spiral, causing wave motion in the axial direction,
The matching position with the second waveform moves along the axial direction. Since the two waveforms have different pitches, the positions of the peaks and valleys to be newly engaged next to the peaks of the first waveform and the valleys of the second waveform that are currently engaged do not match with each other. Therefore,
When the first member rotates and the peak of the first waveform that is being secured comes out of the valley of the corresponding second waveform, the next peak of the first waveform will be the next valley of the corresponding second waveform. The second
The member is driven axially.

In this way, each peak of the first waveform sequentially engages each corresponding valley of the second waveform, thereby causing the second member to move linearly.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 schematically shows the configuration of a transmission mechanism according to the present invention using an embodiment. This transmission mechanism includes a first member 1 on the input side that rotates and a second member 2 on the output side that moves linearly. The first member 1 has a central axis 4 eccentric to the rotation axis 3 by a distance e, and a rod 5 shown by an imaginary line is moved around the rotation axis 3 and along the axial direction. It is formed into a spiral shape that is rotated 360 degrees in the direction of A. The first member 1 is supported so as to be rotatable about the rotating shaft 3 and immovable in the axial direction. The second member 2 consists of a straight rod that is sufficiently long relative to the first member 1. The second member 2 is supported rotatably around the central axis 6 and linearly movable along the axial direction.

As shown in FIG. 2, a first waveform 8 having a sinusoidal cross section is formed on the outer circumferential surface of the first member 1 by a large number of annular grooves 7 carved at a certain pitch along the rotation axis 3. is formed. On the other hand, on the outer circumferential surface of the second member 2, like the first member 1, a large number of annular shapes are carved at a certain pitch slightly smaller than the first waveform 8 along the axial direction, that is, the direction of movement. A second waveform 10 having a sinusoidal cross section is formed by the groove 9 . As best shown in FIG. 2, the first waveform 8
is the number NO of waves of the second waveform 10 whose amplitude is larger than that of the second waveform 10 and whose number N1 of waves corresponds to the total length l.
One less than.

The first member 1 and the second member 2 are arranged one above the other so that the rotating shaft 3 and the central axis 6 are parallel to each other, and the first waveform 8 has a first waveform at the top of the spiral. 2 is engaged with the waveform 10. When viewed from the side as shown in FIG. 2 and FIG. When rotated in this direction, it moves to the right in the figure. Due to this wave motion, the position where the first waveform 8 and the second waveform 10 meet moves to the right in the figure as the first member 1 rotates.

Specifically, at the left end of the first member 1, the first waveform 8 becomes the second waveform.
The first member 1 is moved from the second illustrated state in which it engages the waveform 10 to 9
When rotated by 0 degrees, the first waveform 8 becomes the second waveform 1 at a position approximately fl/4 to the right from the left end, as shown in FIG.
0.

In FIG. 2, the crest 11 of the left end wave of the first waveform 8 fits into the corresponding trough 12 of the second waveform 10. -L As mentioned above, the pitch of the first waveform 8 is slightly larger than that of the second part waveform 10, so in the second and subsequent waves of the first waveform 8, the position of the peak is the same as the corresponding trough of the second waveform 10. They are sequentially shifted to the right with respect to the position of , according to the difference between the two pitches. Therefore,
At the right end of the first member 1, the first waveform 8 is shifted by one wave from the second waveform 10, and the peak part 13 of the Ni-th waveform is the second waveform 1.
It engages with the Ni+1th valley portion 14 of 0, that is, the No.th valley portion 14.

When the first member 1 is slightly rotated in the direction of the arrow A from this state, the peak part 1 of the first waveform 8 corresponds to the second waveform 10.
The peak l5 of the second wave newly enters the second valley 16 of the second waveform 10 while exiting the valley 12 of the second wave. At this point, the peak portion 15 is not aligned with the valley portion 16, so it advances into the valley portion 16 from its tip right side portion 17 while contacting the right side slope 18 of the valley portion 16. Since the first member 1 is fixed in the axial direction, the valley portions 16 are pushed by the peak portions 15, and the second member 2 is
Move to the right in the figure by the difference in pitch between the two until they are completely fitted. At the same time, the second member 2 rotates in the direction of arrow B, opposite to the first member 1, due to the frictional force between the peaks 15 and troughs 16 that are in contact with each other.

In this way, the second member 2 is connected to the corresponding first member. By sequentially engaging and disengaging the peaks of the waveform 8 and the valleys of the second waveform 10, the waveform is sent little by little to the right in the figure along the axial direction. and the first member]. When the second member 2 rotates once, the engagement position with both waveforms 8 and 10 moves in the axial direction by one cycle of the sine wave explained in FIG. That is, it is driven to the right by one pitch, resulting in a very large reduction ratio. Also, of course, if the first part 1 is rotated in the opposite direction, the second member 2
On the contrary, it moves to the left.

The first waveform 8 and the second waveform 10 can generally be expressed by the following equations.

Ro = Ao + Bo ・sin(No ・a) −
= (1) RI = AI +}31 -s]n
(Ni ●α) − (2) Here, Ri, Ro
are the distances from the central axes 4 and 6, respectively, and At ,
Ao is the distance from the central axis to the pitch circle of each waveform 8, 1-0, Bi and Bo are the amplitudes of each sine wave, and α is the displacement in the axial direction.

As mentioned above, in order for the first member 1 and the second member 2 to rotate while transmitting driving force smoothly without interfering with each other, in the above equations (1) and (2), Ni = No. -1,
It is necessary to satisfy the following conditions: Bo≧e and Ao/Bo≧No. Further, these conditions were found to be correct from the results of a computer-based simulation of the operations of the first and second members 1 and 2.

In another embodiment, which is a modification of the first embodiment of the series, the second waveform 10 is formed by an elliptical annular groove, such as a cut when cutting a cylinder with an inclined surface that is not perpendicular to its central axis.
can be formed. In this case, when the first member 1 is rotated, the second member 2 makes a reciprocating linear movement along the axial direction. In addition, in the first embodiment, the first waveform 8 is formed into a spiral that rotates 360 degrees, so that it is continuously driven by the rotation of the first member 1. However, if the turning angle of this spiral is made smaller than 360 degrees, The two members 2 can be moved intermittently linearly. Further, the second part A2 may be a member having various shapes other than the rod, as long as it is fixed in the rotational direction and has a second waveform on a surface facing the first waveform.

FIG. 4 schematically shows a second embodiment of the invention.

As in the first embodiment, the first section 21 has its central axis 23 eccentrically centered by a distance e around the rotating shaft 22 and rotated 360 degrees in the direction of arrow C along the axial direction. It has a spiral shape, is fixed in the axial direction and rotatably supported, and has a sinusoidal cross section consisting of a large number of annular grooves 24 carved at a certain pitch along the rotation axis 22 on the outer periphery. A first waveform 25 is provided. The second member 26 made of a straight rod is supported so as to be linearly movable in the axial direction and rotatable around the central axis 27 as in the first embodiment. Two second waveforms each having a sinusoidal cross section and consisting of a single thread groove 28 rotating in the same direction as the first waveform 25 are carved along the axial direction at a constant pitch slightly smaller than the first waveform 25.

11 Similar to the first embodiment, the first waveform 25 has an amplitude equal to that of the second waveform 25.
It is larger than two waveforms, and the number Nj of its waves is one less than the number No of waves of the second waveform 29 corresponding to the total length l. The first member 21 and the second member 26 are arranged below each other with the rotating shaft 22 and the central axis 27 parallel to each other, and the first waveform 25 is located at the top of the spiral. It is engaged with the second waveform 29.

Furthermore, in this embodiment, the first member 21 and the second member 26 each have straight shafts 31 and 32 at their ends that extend coaxially with the rotating shaft 22 and the central axis 27, and there is a space between them. A gear device is disposed to transmit rotational motion from the first member 21 to the second member 26. This gear device has two gears 33 and 34 in a gear box 35, each having a different number of teeth and meshing with each other. The first gear 33 is fixed to the straight shaft 31'' of the first part 21 by a key 36 so as to rotate integrally therewith. The second gear 34 has a spline 37 formed on the straight shaft 32 of the second member 26 and a groove 38 that matches the spline 37, so that the second gear 34 can move relative to the straight shaft 32 and the shaft 12 in the linear direction and can rotate together. Spline connected.

When the first member 21 is rotated in the direction of arrow C, the second member 26 is rotated in the opposite direction to the first member 21, that is, in the direction of arrow D, by the gear mechanism. At this time, as can be seen from the first embodiment, the second member 26 is driven rightward in the figure by rotating while engaging the first waveform 25 and the two second waveforms having different pitches, but at the same time, the second member 26 is driven rightward in the figure. It is sent to the left in the figure by the groove 28. Therefore, the second member 26 moves leftward or rightward by the difference in the amount of feed in the left-right direction due to the waveforms 25, 29 and the thread groove 28.

For example, if the number of teeth of the first gear 33 is 9 and the number of teeth of the second gear 34 is 10, the second member 26 rotates 9/10 times per rotation of the first member 21 . Here, assuming that the pitch of the second waveform 29 is 2 mm, the second member 26 moves 2 m to the right.
At the same time as m is driven, it moves backward 1.8mm to the left, so
As a result, it moves to the right by 0.2 mm. Conversely, if the number of teeth of the first gear 33 is greater than the number of teeth of the second gear 34, the second member 26 moves to the left. In this way, according to the second embodiment of the present invention, a very large reduction ratio can be obtained by appropriately combining gear devices using splines.

Further, as is obvious to those skilled in the art, it goes without saying that the present invention can be implemented by adding various modifications and changes to the above-described embodiments within the technical scope thereof. For example, instead of the gear device, various other means for transmitting rotational motion can be applied between the first member 21 and the second part trA26.

[Effects of the Invention] As described above, according to the present invention, the first waveform is formed at a constant pitch on the outer peripheral surface of the first member consisting of a spiral rod that revolves around the rotation axis, and the first waveform is formed at a constant pitch. By engaging the second waveforms formed on the two members with different pitches, when the first member is rotated, the peaks of the first waveform push out the valleys of the second waveform in the axial direction due to the difference in both pitches. ,
The second member can be linearly moved along the axial direction, and a large speed reduction ratio can be obtained with a small size and one step. In particular, a larger reduction ratio can be achieved by combining a transmission means for transmitting rotational motion from the first member to the second member.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing a transmission mechanism according to the present invention. FIG. 2 is a partially sectional side view showing a state of engagement between the first member and the second member. Figure 3 shows the second part showing the moon rotated 90 degrees in the first part.
It is a partial cross-sectional side view similar to the figure. FIG. 4 is a side view schematically showing a second embodiment of the present invention. 1...First part phase 2...Second part 3...Rotating shaft 4...Central axis 5...Rod
6... Central axis 7... Annular groove 8... First waveform 9... Annular groove 10... Second waveform 1
1... Peak part 12... Valley part 13... Peak part 14... Valley part 15 15... Peak part 17, 18... Slope 22... Rotating shaft 24... Annular groove 26...Second member 28...Thread grooves 31, 32...Straight shaft 34...Second gear 36...Key 38...Groove 16...Trough 21...First Member 23... Central shaft 25... First waveform 27... Two central shafts... Second waveform 33... First gear 35... Gear box 37... Spline

Claims (3)

[Claims] (1) A transmission mechanism for transmitting power between a first member that rotates and a second member that moves linearly, the first member being fixed in the axial direction and centered around the rotation axis. a first waveform having a certain constant pitch arranged along a spiral rotating along the axial direction;
The member has a second waveform with a certain constant pitch arranged along the direction of movement of the member, and the first waveform and the second waveform are such that the number of waves of the first waveform is 360 degrees. The rotating spirals have pitches that are different from each other by one less than the number of waves of the corresponding second waveform, and
A transmission mechanism characterized by engaging with each other so as to transmit power. (2) The first member is made of a rod that spirals around the rotation axis, and has the first waveform on its outer peripheral surface. Transmission mechanism. (3) The second member is supported rotatably and linearly movable in the axial direction, and the second waveform is formed by a thread groove carved in the outer peripheral surface of the second member along the axial direction. 3. The transmission mechanism according to claim 1, further comprising means for transmitting rotational motion from the first member to the second member at a certain speed ratio.