JPH08200465A - Fine feed mechanism - Google Patents

Abstract

PURPOSE: To provide a fine feed mechanism which obtains a fine feed of converting rotary motion of a high speed rotary motor into a fine linear motion with direct coupling by simplifying a structure further by reducing a receiving space, without individually providing an exclusive use reduction gear of reducing rotation of the motor of high speed rotation and an exclusive use mechanism of converting a rotary motion into a linear motion. CONSTITUTION: A mechanism has a rotor 2 driven to rotate by a motor 1 to have a major diametric part 2a, screw member 4 externally fitted to the rotor 2 to be elastically deformable further to have an external thread part 4a in one end part and an internal thread member 5 of screw-engaging the external thread part 4a of the screw member 4, positioned in the major diametric part 2a of the rotor 2, with an internal thread part 5a in an internal peripheral surface, to fix one end part of the internal thread member 5 to the motor 1, with the screw member 4 making a rotary motion and moving in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minute feed mechanism for converting rotary motion into minute linear motion.

[0002]

2. Description of the Related Art As a conventional minute feed mechanism of this type, there is one used for a brake device as described in, for example, Japanese Patent Laid-Open No. 63-266228. This minute feed mechanism converts the rotation torque of the ultrasonic motor by a reduction gear mechanism for increasing the torque and a torque conversion means having a mechanism section for converting the rotation torque into a linear propulsion force, and transmits it to the friction member. This reduction gear mechanism is specifically configured by a planetary gear mechanism, and the torque conversion means is specifically configured by a linear conversion mechanism including a ball screw mechanism.

However, in such a conventional minute feed mechanism, the rotational movement of the motor is decelerated by the planetary gear mechanism, and the decelerated rotational movement is converted into the linear movement by the ball screw mechanism. Therefore, there is a technical problem that the structure is complicated and a large storage space is required.

[0004]

The present invention has been made in view of such conventional technical problems, and has the following configuration. The configuration of the invention of claim 1 is a motor 1
Rotor 2 which is driven to rotate by and has a long diameter portion 2a.
And a threaded member 4 which is externally fitted to the rotor 2 and is elastically deformable and has a male threaded portion 4a at one end, and a male threaded portion 4a of the threaded member 4 located on the long diameter portion 2a of the rotor 2 And a female screw member 5 that is screw-engaged with the female screw portion 5a,
One end of the female screw member 5 is fixed to the motor 1, and the screw member 4 is rotated and moved in the axial direction. According to a second aspect of the invention, the rotor 1 is rotationally driven by the motor 1 and has the long diameter portion 2a, and the screw member externally fitted to the rotor 2 is elastically deformable and has the male screw portion 4a at one end. 4 and a male screw portion 4a of the screw member 4 located on the long diameter portion 2a of the rotor 2 have a female screw member 5 that screw-engages with a female screw portion 5a on the inner peripheral surface, and one end of the female screw member 5 has a motor 1 It is a minute feed mechanism characterized in that it is rotatably supported by the screw member 4 and is made non-rotatable to move in the axial direction. Claim 3
According to the configuration of the invention described above, a rotor 2 that is rotationally driven by a motor 1 and has a long diameter portion 2a, and a screw member 4 that is externally fitted to the rotor 2, is elastically deformable, and has a male screw portion 4a at the other end. , The long diameter portion 2 of the rotor 2 on the female screw portion 5a on the inner peripheral surface.
a female screw member 5 with which the male screw portion 4a of the screw member 4 located at a is engaged, and one end portion of the screw member 4 has a motor 1
And a female screw member 5 is rotationally moved and moved in an axial direction. According to a fourth aspect of the present invention, the rotor 1 is rotationally driven by the motor 1 and has the long diameter portion 2a, and the screw externally fitted to the rotor 2 is elastically deformable and has the male screw portion 4a at the other end. The member 4 and the screw member 4 located on the long diameter portion 2a of the rotor
Has a female screw member 5 threadably engaged with a female screw portion 5a on the inner peripheral surface, one end of the screw member 4 is rotatably supported by the motor 1, and the female screw member 5 is non-rotatable. The fine feed mechanism is characterized in that the fine feed mechanism is moved in the axial direction. According to a fifth aspect of the invention, the rotor 2 is rotationally driven by the motor 1 and has the long diameter portion 2a, and the male screw portions 4a, 4 which are fitted onto the rotor 2 and are elastically deformable.
The screw member 4 having c on both end sides and the male screw portion 4a at one end of the screw member 4 located on the long diameter portion 2a of the rotor 2 are
A female screw member 5 that is screw-engaged with a female screw portion 5a on the inner peripheral surface,
The male screw portion 4c at the other end of the screw member 4 located on the long diameter portion 2a of the rotor 2 has a movable screw member 8 screwed into the female screw portion 8a on the inner peripheral surface, and one end of the female screw member 5 is The minute feed mechanism is characterized in that the movable screw member 8 is fixed to the motor 1 and moves in the axial direction.

[Action]

According to the first aspect of the invention, when the rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a of the rotor 2 is rotationally moved together with the motor shaft 1a, and the screw member 4 extends along the rotor 2. Elastically deforms while maintaining its shape. Thereby, the position of the major axis of the male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the fixed female screw member 5, and the female screw member 5
The position of the male screw portion 4a which is not engaged with the female screw portion 5a gradually moves in the circumferential direction.

Now, when the rotor 2 makes one revolution, the circumferential length of the male screw portion 4a of the screw member 4 is shorter than the circumferential length of the female screw portion 5a of the fixed female screw member 5, so that the circumferential length of the female screw member 5 is small. The screw member 4 rotates in the direction opposite to the rotation direction of the motor 1 by the amount of the shortage. Further, the screw member 4 moves in the axial direction as much as the screw member 4 rotates.

Since the difference in circumferential length between the male screw portion 4a of the screw member 4 and the female screw portion 5a of the female screw member 5 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per revolution of the motor 1 is small. Is small, and accordingly, the amount of relative movement in the axial direction is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement (and rotational movement) of the screw member 4.
When the motor 1 is rotated in the reverse direction, the screw member 4 linearly moves (and rotates) in the opposite direction. By the minute linear movement of the screw member 4, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

According to the second aspect of the present invention, when the rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a of the rotor 2 rotates together with the motor shaft 1a, and the screw member 4 has a shape along the rotor 2. Elastically deforms while maintaining. This allows
The position of the major axis of the male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the female screw member 5 and the position of the male screw portion 4a that does not engage with the female screw portion 5a of the female screw member 5 gradually move in the circumferential direction. go.

Now, when the rotor 2 makes one revolution, the circumference of the screw member 4 is shorter than the circumference of the female screw member 5, so that the circumference of the screw member 4 is shorter and the screw member 4 and the female screw are smaller. A rotational force acts on the member 5. Then, the screw member 4
If the rotation is restricted, the female screw member 5 rotates in the same direction as the rotation direction of the motor 1. Further, the screw member 4 moves in the axial direction by the amount of rotation of the female screw member 5.

Since the difference in circumferential length between the screw member 4 and the female screw member 5 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per one rotation of the motor 1 is small, and accordingly, the axis line. The amount of relative movement in the direction is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement of the screw member 4. When the motor 1 is rotated in the reverse direction, the screw member 4 linearly moves in the opposite direction. By the minute linear movement of the screw member 4, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

According to the third aspect of the present invention, when the rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a of the rotor 2 rotates together with the motor shaft 1a, and the screw member 4 has a shape along the rotor 2. Elastically deforms while maintaining. This allows
The position of the major axis of the male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the female screw member 5 and the position of the male screw portion 4a that does not engage with the female screw portion 5a of the female screw member 5 gradually move in the circumferential direction. go.

Now, when the rotor 2 makes one revolution, the circumferential length of the screw member 4 is shorter than the circumferential length of the female screw member 5, so that the female screw member 5 becomes a motor as much as the circumferential length of the screw member 4 is short. It rotates in the same direction as the rotation direction of 1. Since one end of the screw member 4 is fixed to the motor 1, it does not rotate or move in the axial direction. As a result of the relative rotation between the screw member 4 and the female screw member 5, the female screw member 5 that is screw-engaged with the male screw portion 4a and the female screw portion 5a moves in the axial direction.

Since the circumferential length difference between the screw member 4 and the female screw member 5 is small, the relative rotational difference between the screw member 4 and the female screw member 5 per one rotation of the motor 1 is small, and accordingly, the female screw The relative movement amount of the member 5 in the axial direction is also small.
Thus, the rotational movement of the motor 1 is converted into a minute linear movement (and rotational movement) of the female screw member 5. When the motor 1 is rotated in the reverse direction, the female screw member 5 linearly moves (and rotates) in the opposite direction. By the minute linear movement of the female screw member 5, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

According to the fourth aspect of the invention, when the rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a of the rotor 2 rotates together with the motor shaft 1a, and the screw member 4 has a shape along the rotor 2. Elastically deforms while maintaining. This allows
The position of the major axis of the male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the female screw member 5 and the position of the male screw portion 4a that does not engage with the female screw portion 5a of the female screw member 5 gradually move in the circumferential direction. go.

Now, when the rotor 2 makes one revolution, the circumferential length of the screw member 4 is shorter than the circumferential length of the female screw member 5, and
Since one end of the screw member 4 is rotatably supported by the motor 1, the screw member 4 rotates in the direction opposite to the rotation direction of the motor 1 by the amount of the short circumferential length. This screw member 4
If the rotation of the female screw member 5 is restricted by the rotation of, the female screw member 5 moves in the axial direction.

Since the circumferential length difference between the screw member 4 and the female screw member 5 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per one rotation of the motor 1 is small, and accordingly, the female screw The amount of movement of the member 5 in the axial direction is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement of the female screw member 5. By the minute linear movement of the female screw member 5, for example, a friction pad of a disc brake, which abuts on the female screw member 5, can be pushed out to generate a braking force.

According to the fifth aspect of the present invention, when the rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a of the rotor 2 rotates together with the motor shaft 1a, and the screw member 4 has a shape along the rotor 2. Elastically deforms while maintaining. This allows
The position of the major axis of the male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the fixed female screw member 5 and the position of the male screw portion 4a that does not engage with the female screw portion 5a of the female screw member 5 gradually move in the circumferential direction. Do it. At the same time, the position of the major axis of the male screw portion 4c of the screw member 4 that engages with the female screw portion 8a of the movable screw member 8 and the position of the male screw portion 4c that does not engage with the female screw portion 8a of the movable screw member 8 gradually become circumferential. Move to.

Now, when the rotor 2 makes one revolution, the circumferential length of the screw member 4 is shorter than the circumferential length of the female screw member 5. Therefore, the screw member 4 is fixed to the female screw member 5 by the short circumferential length. It rotates and moves in the axial direction. As a result, the movable screw member 8 moves in the axial direction with respect to the female screw member 5. The rotational movement of the movable screw member 8 is constrained. In addition,
A male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the female screw member 5 and a male screw portion 4c of the screw member 4 that engages with the female screw portion 8a of the movable screw member 8 are provided with the same right screw or the same pitch. When the left-hand thread is used, the movable screw member 8 cannot rotate, so that the movable screw member 8 does not move in the axial direction.

Since the circumferential length difference between the screw member 4, the female screw member 5 and the movable screw member 8 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per rotation of the motor 1 and the axis line. The relative movement amount in the direction is small, and accordingly, the relative movement amount in the axial direction of the movable screw member 8 is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement of the movable screw member 8 in the axial direction. When the motor 1 is rotated in the reverse direction, the movable screw member 8 linearly moves in the opposite direction. By the minute linear movement of the movable screw member 8 in the axial direction, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention. In the figure, reference numeral 1 indicates a motor driven by electricity, and a motor shaft 1a thereof has a key 1b which extends in the axial direction and is fixed thereto. This motor shaft 1a has
An elliptical rotor 2 is fitted onto the key 1b so as not to rotate relative to the key 1b and to be movable in the axial direction. Therefore,
The rotor 2 has a long diameter portion 2a, and the center portion thereof is splined to the motor shaft 1a. Further, an elastically deformable screw member 4 is fitted onto the outer circumference of the rotor 2 via a plurality of rollers 3. The plurality of rollers 3 are arranged on the outer circumference of the rotor 2 at a predetermined interval and held by a holder (not shown), and each roller 3 is in contact with the outer circumferential surface of the rotor 2. The screw member 4 is made of spring steel and has a cylindrical shape in a free state. The one end of the screw member 4 is formed with a male screw portion 4a having a predetermined pitch, and the other end thereof is formed by a side plate 4b serving as a strength member. It is covered.

A female screw member 5 having a cylindrical shape, one end of which is concentrically fixed to the motor 1 and is fixed, is provided.
A female screw portion 5a is formed on the inner peripheral surface of the female screw member 5, and the male screw portion 4a of the elastically deformable screw member 4 is screw-engaged with the female screw portion 5a. The female screw portion 5a has the same pitch as the male screw portion 4a, and is formed on the inner peripheral surface of the female screw member 5 to be long in the axial direction. Then, the screw member 4
Is elastically deformed along the outer shape of the rotor 2 via the roller 3, and only the male screw portion 4a located in the long diameter portion 2a of the rotor 2 partially engages with the female screw portion 5a of the female screw member 5. The screw engagement portion gradually moves in the circumferential direction as the rotor 2 rotates.

Next, the operation of the first embodiment will be described. When the elliptical rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a and the short diameter portion of the rotor 2 are moved to the motor shaft 1a.
The screw member 4 elastically deforms while maintaining the elliptical shape along the rotor 2 via the roller 3 while rotating. Thereby, the position of the major axis of the male screw part 4a of the screw member 4 engaging with the female screw part 5a of the fixed female screw member 5 and the position of the minor diameter of the male screw part 4a not engaging with the female screw part 5a of the female screw member 5. Gradually moves in the circumferential direction.

Now, if the elliptical rotor 2 makes one revolution,
Since the circumferential length of the male screw portion 4a of the screw member 4 is shorter than the circumferential length of the female screw portion 5a of the fixed female screw member 5, the screw member 4 is insufficient in the circumferential length of the female screw member 5 so that the screw member 4 has a smaller length.
The direction opposite to the rotation direction of (indicated by arrow A in FIGS. 1 and 2).
Rotate to. Then, the screw member 4 moves in the axial direction (indicated by the arrow B in FIG. 1) by the amount of the rotational movement of the screw member 4. The rotor 2 receives the frictional force of the roller 3 and moves slightly in the same direction as the screw member 4 while being guided by the key 1b.

Since the difference in circumferential length between the male screw portion 4a of the screw member 4 and the female screw portion 5a of the female screw member 5 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per revolution of the motor 1 is small. Is small, and accordingly, the amount of relative movement in the axial direction is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement (and rotational movement) of the screw member 4.
When the motor 1 is rotated in the reverse direction, the screw member 4 linearly moves (and rotates) in the opposite direction. By the minute linear movement of the screw member 4, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

FIG. 3 shows the second embodiment of the present invention.
The parts substantially the same as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted. In the second embodiment, the step portion 4c formed on the side plate 4b at the other end portion of the elastically deformable screw member 4 is engaged with the step portion 6a of the non-rotatable fixing member 6, and the screw member 4 is rotated.
The rotation of is restrained. 25 is a side plate 4b and a fixing member 6
It is a filling member that fills the space between. The fixing member 6 is, for example, a back metal of a friction pad of a disc brake. Further, one end of the female screw member 5 is concentrically supported by the motor 1 via a bearing 7 so as to be rotatable but immovable in the axial direction. The bearing 7 is a ball bearing so as to support both radial load and thrust load.

Next, the operation of the second embodiment will be described. When the elliptical rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a and the short diameter portion of the rotor 2 are moved to the motor shaft 1a.
The screw member 4 is elastically deformed while rotating along with the rotor 3 while maintaining the elliptical shape along the rotor 2 via the roller 3. Thereby, the position of the major axis of the male screw part 4a of the screw member 4 that engages with the female screw part 5a of the female screw member 5 and the position of the minor diameter of the male screw part 4a that does not engage with the female screw part 5a of the female screw member 5 gradually. It moves in the circumferential direction.

Now, if the elliptical rotor 2 makes one revolution,
Since the circumferential length of the screw member 4 is shorter than the circumferential length of the female screw member 5, the rotational force acts between the screw member 4 and the female screw member 5 due to the shorter circumferential length of the screw member 4. Since the rotation of the screw member 4 is restricted by the engagement of the two step portions 4c and 6a, the female screw member 5 is in the same direction as the rotation direction of the motor 1 (shown by an arrow C in FIG. 3). Rotate to. However, the female screw member 5 does not move in the axial direction due to the action of the bearing 7. Then, the screw member 4 moves in the axial direction by the amount of rotation of the female screw member 5 and moves the fixing member 6. The rotor 2 receives the frictional force of the roller 3 and moves slightly in the same direction as the screw member 4 while being guided by the key 1b.

Since the difference in circumferential length between the screw member 4 and the female screw member 5 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per one rotation of the motor 1 is small, and accordingly, the axis line. The amount of relative movement in the direction is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement of the screw member 4 and the fixing member 6. When the motor 1 is rotated in the reverse direction, the screw member 4 (and the fixing member 6) linearly moves in the opposite direction. By the minute linear movement of the screw member 4, the fixing member 6, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

FIG. 4 shows the third embodiment of the present invention.
The parts substantially the same as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted. In the third embodiment, in the elastically deformable screw member 4, the side plate 4b is omitted, the other end side is elastically deformable, and one end portion is concentrically fixed to the motor 1. On the other hand, the female screw member 5 has the female screw portion 5a and the screw member 4
The male screw portion 4a formed at the other end of the is partially screw-engaged, and is rotatable and movable in the axial direction. The other end of the screw member 4 is externally fitted to the elliptical rotor 2 via a plurality of rollers 3, and only the male screw portion 4a located on the long diameter portion 2a of the rotor 2 is part of the female screw portion 5a of the female screw member 5. Are screwed together. The female screw member 5 is supported by a supporting member (not shown) and is maintained in a concentric state with the motor 1. The other end of the female screw member 5 is covered by a side plate 5b as a strength member.

Next, the operation of the third embodiment will be described. When the elliptical rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a and the short diameter portion of the rotor 2 are moved to the motor shaft 1a.
The screw member 4 is elastically deformed while rotating along with the rotor 3 while maintaining the elliptical shape along the rotor 2 via the roller 3. Thereby, the position of the major axis of the male screw part 4a of the screw member 4 that engages with the female screw part 5a of the female screw member 5 and the position of the minor diameter of the male screw part 4a that does not engage with the female screw part 5a of the female screw member 5 gradually. It moves in the circumferential direction.

Now, if the elliptical rotor 2 makes one revolution,
Since the circumferential length of the screw member 4 is shorter than the circumferential length of the female screw member 5, the female screw member 5 has a shorter circumferential length.
Rotates in the same direction as the rotation direction of the motor 1 (indicated by arrow D in FIG. 4). Since one end of the screw member 4 is fixed to the motor 1, it does not rotate or move in the axial direction. Therefore, the rotor 2 also does not move in the axial direction. Then, by the relative rotation of the screw member 4 and the female screw member 5,
The female screw member 5, which is screw-engaged with the male screw portion 4a and the female screw portion 5a, moves in the axial direction.

Since the circumferential length difference between the screw member 4 and the female screw member 5 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per one rotation of the motor 1 is small, and accordingly, the female screw The relative movement amount of the member 5 in the axial direction is also small.
Thus, the rotational movement of the motor 1 is converted into a minute linear movement (and rotational movement) of the female screw member 5. When the motor 1 is rotated in the reverse direction, the female screw member 5 linearly moves (and rotates) in the opposite direction. By the minute linear movement of the female screw member 5, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

FIGS. 5 and 6 show a fourth embodiment of the present invention, in which the substantially same parts as those in the first and third embodiments are designated by the same reference numerals and the description thereof will be omitted. In the fourth embodiment, one end of the screw member 4 is supported concentrically on the outer peripheral surface of the motor 1 via a bearing 9 so as to be immovable in the axial direction and is elastically deformable on the other end side. ing. on the other hand,
The female screw member 5 is movable in the axial direction by partially engaging the female screw portion 5a with the male screw portion 4a formed at the other end of the screw member 4. The screw member 4 is externally fitted to the elliptical rotor 2 via a plurality of rollers 3, and only the male screw portion 4a located in the long diameter portion 2a of the rotor 2 is partially screwed to the female screw portion 5a of the female screw member 5. I am fit. The female screw member 5 is slidably engaged with a tip portion of a guide member 10 fixed to a fixing portion (not shown) in a groove portion 5c which is an uneven portion formed by extending in the axial direction on the outer peripheral surface, It is not rotatable and is supported by a support member (not shown) so that it is concentric with the motor 1. The other end of the female screw member 5 is covered with a side plate 5b as a strength member.

Next, the operation of the fourth embodiment will be described. When the elliptical rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a and the short diameter portion of the rotor 2 are moved to the motor shaft 1a.
With the rotation, the screw member 4 elastically deforms while maintaining the elliptical shape along the rotor 2. Thereby, the male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the female screw member 5.
The position of the longest diameter and the position of the shortest diameter of the male screw portion 4a which is not engaged with the female screw portion 5a of the female screw member 5 gradually move in the circumferential direction.

Now, if the elliptical rotor 2 makes one revolution,
Since the circumferential length of the screw member 4 is shorter than the circumferential length of the female screw member 5 and one end of the screw member 4 is rotatably supported by the motor 1, the screw member 4 has a circumferential length of The motor 1 rotates in the opposite direction (indicated by arrow E in FIG. 5) from the rotation direction of the motor 1 for a short time. By the rotation of the screw member 4, the guide member 10 engages with the groove 5c and the rotation of the female screw member 5 is restricted, and the female screw member 5 moves in the axial direction (indicated by arrow F in FIG. 5). Since the screw member 4 does not move in the axial direction, the rotor 2 also does not move in the axial direction.

Since the circumferential length difference between the screw member 4 and the female screw member 5 is small, the relative rotation difference between the screw member 4 and the female screw member 5 per one rotation of the motor 1 is small, and accordingly, the female screw The amount of movement of the member 5 in the axial direction is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement of the female screw member 5. By the minute linear movement of the female screw member 5, for example, a friction pad of a disc brake, which is in contact with the side plate 5b at the other end of the female screw member 5, can be pushed out to generate a braking force.

FIG. 7 shows the fifth embodiment of the present invention.
The parts substantially the same as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted. In the fifth embodiment, the screw member 4 has a male screw portion 4a formed at one end and a male screw portion 4c formed at the other end of the outer peripheral surface having a short tubular shape.
a and 4c are right-handed screws or left-handed screws having different pitches or directions.

Then, the female screw portion 5a at the other end of the female screw member 5 whose one end is fixed concentrically to the motor 1 is partially screw-engaged with one male screw portion 4a of the screw member 4, and the movable screw member 8 The female screw portion 8a on the inner peripheral surface of one end is partially threadedly engaged with the other male screw portion 4c. The screw member 4 is externally fitted to the elliptical rotor 2 via a plurality of rollers 3, and has a pair of male screw portions 4a, 4 located on the long diameter portion 2a of the rotor 2.
Only c is partially threadedly engaged with the female screw portion 5a of the female screw member 5 and the female screw portion 8a of the movable screw member 8, respectively. The movable screw member 8 has a cylindrical shape, and a distal end portion of a guide member 10 fixed to a fixing portion (not shown) is slidable in a groove portion 8c which is an uneven portion formed by extending in the axial direction on the outer peripheral surface. Engagement, rotation is restrained, and it is supported by a support member (not shown), and the concentric state with the motor 1 is maintained. 8b is a side plate as a strength member that covers the other end.

Next, the operation of the fifth embodiment will be described. When the elliptical rotor 2 is rotationally driven by the motor 1, the long diameter portion 2a and the short diameter portion of the rotor 2 are moved to the motor shaft 1a.
With the rotation, the screw member 4 elastically deforms while maintaining the elliptical shape along the rotor 2. Thereby, the position of the major axis of the one male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the fixed female screw member 5 and the one male screw portion 4a of the one male screw portion 4a that is not engaged with the female screw portion 5a of the female screw member 5. The position of the minor axis gradually moves in the circumferential direction. At the same time, the position of the major axis of the other male screw portion 4c of the screw member 4 that engages with the female screw portion 8a of the movable screw member 8 and the short length of the other male screw portion 4c that does not engage with the female screw portion 8a of the movable screw member 8. The diameter position gradually moves in the circumferential direction.

Now, if the elliptical rotor 2 makes one revolution,
Since the circumferential length of the one male screw portion 4a of the screw member 4 is shorter than the circumferential length of the female screw portion 5a of the female screw member 5, the screw member 4
The screw member 4 rotates and moves in the axial direction with respect to the fixed female screw member 5 by the short circumferential length. By the rotation of the screw member 4, the movable screw member 8 moves in the axial direction with respect to the screw member 4, and as a result, the movable screw member 8 moves in the axial direction with respect to the female screw member 5 (arrow G in FIG. 7). Indicated by.) The screw member 4 slightly moves while being guided by the key 1b. The rotational movement of the movable screw member 8 is restricted because the tip end portion of the guide member 10 is slidably engaged with the axial groove portion 8c. It should be noted that one male screw portion 4a of the screw member 4 that engages with the female screw portion 5a of the female screw member 5,
In the case where the other male screw portion 4c of the screw member 4 that engages with the female screw portion 8a of the movable screw member 8 is formed by the right screw or the left screw having the same pitch and the same direction, the movable screw member 8
Is not rotatable, the movable screw member 8 does not move in the axial direction.

Since the circumferential length difference between the screw member 4, the female screw member 5 and the movable screw member 8 is small, the relative rotational difference between the screw member 4 and the female screw member 5 per rotation of the motor 1 and the axis line. The relative movement amount in the direction is small, and accordingly, the relative movement amount in the axial direction of the movable screw member 8 is also small. Thus, the rotational movement of the motor 1 is converted into a minute linear movement of the movable screw member 8 in the axial direction. When the motor 1 is rotated in the reverse direction, the movable screw member 8 linearly moves in the opposite direction. By the minute linear movement of the movable screw member 8 in the axial direction, for example, the friction pad of the disc brake can be pushed out to generate the braking force.

By the way, in the above-mentioned first to fifth embodiments, the long diameter portions 2a at both ends in the diameter direction of the elliptical rotor 2 are used.
The two end portions of the screw member 4 in the radial direction by the female screw member 5
Although (and the movable screw member 8) is screw-engaged, if a part of the screw member 4 is screw-engaged with a part of the female screw member 5 (and the movable screw member 8), the stability is slightly deteriorated. The same effect is theoretically obtained. Therefore, a half shape obtained by cutting the elliptical shape in the minor axis direction is given to the rotor 2, and only one of the major diameter portions 2a of the screw member 4 is partially screwed into the female screw member 5 (and the movable screw member 8). It is also possible.

FIGS. 8 and 9 show a sixth embodiment of the present invention, in which substantially the same parts as those in the first embodiment are designated by the same reference numerals and their description is omitted. In the sixth embodiment, the eccentric screw member 12 is attached to the motor shaft 1a of the motor 1 attached to the fixing member 11 (for example, the caliper of the disc brake) instead of the elliptical rotor 2. Eccentric screw member 12
Is constituted by a pair of screw members 22 and 32 rotatably supported by the eccentric support member 14 fixed to the motor shaft 1a. The eccentric support member 14 has a first eccentric portion 14a at one end.
And a second eccentric portion 14b at the other end, which is positioned and fixed to the motor shaft 1a by a key 1b indicated by a two-dot chain line, and a fixing member 11 is provided by a thrust bearing 19 with a spacing member 18 interposed therebetween. It is rotatably supported on.

First eccentric portion 14a and second eccentric portion 14b
Form a cylindrical surface which is eccentric in the radial direction of the motor shaft 1a by the same length. The screw members 22 and 32 are formed with male screw portions 22a and 32a of the same pitch on the outer circumference to have the same diameter, and are rotatable with bearings 16 and 17 interposed in the first eccentric portion 14a and the second eccentric portion 14b, respectively. It is supported. Thus, the pair of screw members 22 and 32 are rotatably arranged such that the centers thereof are offset from each other in the radial direction of the motor shaft 1a, and the male screw portions 22a and 22a protruding from the screw members 22 and 32 by the same length in the radial direction. 32a is the large diameter screw member 13
Are partially threadedly engaged with the female screw portions 13a on the inner peripheral surface of the. That is, the male screw portions 22 a and 32 a of the screw members 22 and 32 are the female screw portions 13 of the large diameter screw member 13.
the same pitch as a, and the male screw portions 22a, 32a
The diameter of is set to be slightly smaller than the diameter of the female screw portion 13a.

The one end of the large-diameter screw member 13 is fitted in the fixing member 11 so as to be movable in the axial direction, and is arranged concentrically with the motor shaft 1a, and the step portion 1 at the other end.
3c is fixed via the stuffing member 25 to the non-rotatable fixing member 6
The rotation is restricted by engaging the stepped portion 6a (for example, the back metal of the friction pad of the disc brake).

Next, the operation of the sixth embodiment will be described. When the eccentric support member 14 is rotationally driven by the motor 1, the pair of eccentric screw members 22 and 32 have their respective male screws due to the relative rotation of the first eccentric portion 14a and the second eccentric portion 14b. The screw engagement points between the portions 22a and 32a and the female screw portion 13a of the large-diameter screw member 13 gradually move in the circumferential direction, and substantially revolve. At the same time, the pair of eccentric screw members 22 and 32 are transmitted while the rotation of the motor shaft 1a is being decelerated by the action of the bearings 16 and 17, and rotate about the motor shaft 1a at a low speed to rotate. 22a, 32a and the screw engagement portion between the female screw portion 13a of the large-diameter screw member 13 gradually moves in the circumferential direction.
That is, since the bearings 16 and 17 have a predetermined frictional resistance force, some co-rotation occurs between the eccentric support member 14 and the pair of screw members 22 and 32.

When the motor 1 makes one revolution, the large-diameter screw member 1
3 relatively moves in the axial direction based on the combination of the substantial revolution movement and the rotation movement of the pair of eccentric screw members 22 and 32. That is, a pair of eccentric screw members 22, 3
If 2 makes a substantial revolution movement, the screw members 22, 32
Of the large-diameter screw member 13 is moved in the circumferential direction at the screw engagement portion with the female screw portion 13a, and the female screw portion 13a and the male screw portion 22 are moved.
The large-diameter screw member 13 slightly moves in the axial direction on the basis of the difference in circumferential length from the a and 32a. When the pair of eccentric screw members 22 and 32 perform a rotation movement, the large-diameter screw member 13 moves in the axial direction like a normal bolt and nut that is screwed all around.

Thus, the pair of eccentric screw members 2
Since the rotation motions of 2 and 32 are generated based on the frictional resistance force of the bearings 16 and 17, rotation delay occurs in the screw members 22 and 32 in the direction opposite to the rotation direction of the motor 1. Due to the rotation delay of the screw members 22 and 32, the same operation as that in which the circumferential lengths of the male screw portions 22a and 32a of the eccentric screw member 12 are shorter than the circumferential length of the female screw portion 13a of the large diameter screw member 13 is performed. Occurs. At this time, the apparent circumferential length difference between the eccentric screw member 12 and the large-diameter screw member 13 is small, but the motor shaft 1a
Compared to the case where a pair of eccentric screw members 22 and 32 are fixed to the eccentric screw member 12,
The relative amount of movement of the large-diameter screw member 13 in the axial direction also decreases by the amount of the small rotation delay. In addition, since the substantial revolution movement of the pair of eccentric screw members 22 and 32 is performed based on the rotation delay of the screw members 22 and 32,
Large-diameter screw member 13 generated by this substantial revolution movement
The amount of movement in the axial direction of is extremely small. Further, the large-diameter screw member 13 has a step 6a of a fixing member 6 (for example, a back metal of a friction pad of a disc brake) whose step 13c cannot rotate.
, It does not rotate.

If the large-diameter screw member 13 is pushed out in the axial direction and the fixing member 6 is pressed against a member not shown (for example, a rotating disc of a disc brake), the screw members 22, 3
The frictional force due to the screw engagement between the male screw portions 22a and 32a of No. 2 and the female screw portion 13a of the large-diameter screw member 13 becomes large, and the eccentric support member 14 has a predetermined frictional resistance force of the bearings 16 and 17.
It becomes difficult for co-rotation between the pair of screw members 22 and 32 to occur. As a result, the screw members 22 and 32 have only a substantially revolving motion in which the screw engagement portion with the female screw portion 13a of the large-diameter screw member 13 moves in the circumferential direction, and the female screw portion 13a and the male screw portions 22a and 32a move. Based on the difference in circumference,
The large-diameter screw member 13 moves only slightly in the axial direction, and the fixing member 6 is strongly pressed against a member not shown. At that time, the male screw portions 22a and 32a of the screw members 22 and 32 and the female screw portion 13a of the large diameter screw member 13 are formed.
Based on the large frictional force due to the screw engagement with the screw member 2
2, 32 relatively rotate in a direction opposite to the rotation direction of the motor 1. Thus, the rotational movement of the motor 1 is converted into a minute linear movement of the screw member 4. When the motor 1 is rotated in the reverse direction, the large diameter screw member 13 linearly moves in the opposite direction. By such a minute linear movement of the large-diameter screw member 13, for example, the friction pad of the disc brake can be pushed out to generate a braking force.

In the sixth embodiment, a plurality of eccentric screw members 22 and 32 are arranged. However, if the balance of rotation is sacrificed, one eccentric screw member 22 or 32 is arranged. It is also possible to obtain the same effect.
Further, the male screw portions 22a of the eccentric screw members 22, 32,
Even if the pitch of 32a and the pitch of the female threaded portion 13a of the large-diameter threaded member 13 are different, substantially the same action can be obtained as long as they can be screwed partially.

[0051]

As can be understood from the above description,
According to the minute feed mechanism of the present invention, the following effects can be obtained. According to the invention of claims 1 to 5, since the screw member and the female screw member having slightly different diameters are combined so that the screw member can be elastically deformed, a circle is formed between the screw member and the female screw member for one rotation of the motor. Only the rotation of the circumference difference occurs. As a result, the rotary motion of the high-speed motor can be converted into a minute linear motion by direct connection without separately providing a dedicated reducer for reducing the rotation of the high-speed motor and a dedicated mechanism for converting the rotary motion into the linear motion. The minute feed that directly converts can be obtained with a simple structure and a reduced storage space.

[Brief description of drawings]

FIG. 1 is a sectional view showing a minute feed mechanism according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view showing a minute feeding mechanism according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a minute feed mechanism according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing a minute feed mechanism according to a fourth embodiment of the present invention.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a sectional view showing a minute feed mechanism according to a fifth embodiment of the present invention.

FIG. 8 is a sectional view showing a minute feed mechanism according to a sixth embodiment of the present invention.

9 is a sectional view taken along line IX-IX in FIG.

[Explanation of symbols]

1: Motor, 1a: Motor shaft, 2: Rotor, 2a: Long diameter part, 3: Roller, 4: Screw member, 4a, 4c: Male screw part, 5: Female screw member, 5a: Female screw part, 5c: Groove part (uneven part) ), 8: movable screw member, 8a: female screw portion, 10: guide member, 11: fixed member, 12: eccentric screw member, 13:
Large-diameter screw member, 14: eccentric support member, 14a: first eccentric portion, 14b: second eccentric portion, 22, 32: screw members.

Claims (5)

[Claims] 1. A rotor (2) rotatably driven by a motor (1) and having a long diameter portion (2a), and an externally fitted rotor (2) which is elastically deformable and has a male screw portion (one end). Four
a) and a male screw part (4a) of the screw member (4) located on the long diameter part (2a) of the rotor (2).
Has a female screw member (5) threadably engaged with the female screw portion (5a) of the inner peripheral surface, one end of the female screw member (5) is fixed to the motor (1), and the screw member (4) rotates. A minute feed mechanism characterized by movement and movement in the axial direction. 2. A rotor (2) which is rotationally driven by a motor (1) and has a long diameter portion (2a), and is externally fitted to the rotor (2), is elastically deformable and has a male screw portion (one end). Four
a) and a male screw part (4a) of the screw member (4) located on the long diameter part (2a) of the rotor (2).
Has a female screw member (5) threadably engaged with a female screw portion (5a) on the inner peripheral surface, one end of the female screw member (5) is rotatably supported by the motor (1), and the screw member (4 ) Is made non-rotatable and moves in the axial direction. 3. A rotor (2) rotatably driven by a motor (1) and having a long diameter portion (2a), and an outer threaded portion which is externally fitted to the rotor (2) and is elastically deformable and at the other end portion. (4
a) and a female screw portion (5) on the inner peripheral surface.
a) has a female screw member (5) with which the male screw portion (4a) of the screw member (4) located in the long diameter portion (2a) of the rotor (2) is screw-engaged, and one end of the screw member (4) A minute feeding mechanism characterized in that the part is fixed to the motor (1), and the female screw member (5) performs rotational movement and axial movement. 4. A rotor (2) rotatably driven by a motor (1) and having a long diameter portion (2a), and an outer threaded portion externally fitted to the rotor (2), which is elastically deformable and has a male screw portion at the other end. (4
a) and a male screw part (4a) of the screw member (4) located on the long diameter part (2a) of the rotor (2).
Has a female screw member (5) threadably engaged with a female screw portion (5a) of the inner peripheral surface, and one end of the screw member (4) is rotatably supported by the motor (1). ) Is made non-rotatable and moves in the axial direction. 5. A rotor (2) rotatably driven by a motor (1) and having a long diameter portion (2a), and male screw portions (4a, 4c) externally fitted to the rotor (2) and elastically deformable. )
And a male screw portion (4a) at one end of the screw member (4) located on the long diameter portion (2a) of the rotor (2) has a female screw portion (5a) on the inner peripheral surface. ), And a long diameter part (2) of the rotor (2).
a), the other end of the screw member (4) located at the other end (4)
c) has a movable screw member (8) threadably engaged with the female screw portion (8a) of the inner peripheral surface, one end of the female screw member (5) is fixed to the motor (1), and the movable screw member (8) is fixed. 8) A minute feeding mechanism characterized by moving in the axial direction.