JP2020180661A - Driving device and electronic device - Google Patents

Abstract

To reduce assembly work hours, achieve downsizing, and improve design flexibility in a driving mechanism (a geared motor) which moves a driving object.SOLUTION: A driving mechanism includes: a lead screw which is connected to a driving source at one end part and extends in an axial direction and in which a thread is formed at an outer periphery; a nut member which is threadedly engaged with the thread of the lead screw; a housing base disposed at the other side of the lead screw; and a housing cover which is disposed at the other side of the lead screw and fits in the inner side of the housing base. A first recessed part formed to the radial inner side is provided near the other end part of the lead screw. A first surface of the housing base and a second surface of the housing cover form a second recessed part recessed to the radial outer side. Spherical bodies arranged in a circumferential direction are disposed between the first recessed part and the second recessed part.SELECTED DRAWING: Figure 4

Description

The present invention relates to a drive device or the like that transmits the rotation of a motor to drive an object.

Conventionally, there is a drive device that uses a reed screw to convert the rotation of a motor into a reciprocating motion in the axial direction to drive an object to be driven. Such a drive device is configured to include a bearing that rotatably supports the shaft of the lead screw. Lead screws provided with such bearings are disclosed in, for example, Patent Documents 1 to 4.

Japanese Unexamined Patent Publication No. 2003-47228 Japanese Unexamined Patent Publication No. 8-186950 Japanese Unexamined Patent Publication No. 4-249209 International Publication No. 2015/093186

The conventional lead screw bearing often employs a commercially available ball bearing (ball bearing) or a configuration in which a ball is arranged at the tip of the shaft. In such a configuration, in the configuration using ball bearings, the inner ring and the shaft are fixed by adhesion or caulking, but the assembly man-hours are increased by the assembly process such as adhesion or caulking, and the size of the shaft is limited. There were times when it happened. Further, in the configuration in which the ball is arranged at the tip of the shaft, the size in the axial direction may become large or a problem may occur in stability.

The present invention adopts the following means in order to solve the above problems and the like. In the following description, reference numerals and the like in the drawings are added in parentheses to facilitate understanding of the invention, but each component of the present invention is not limited to those added. It should be widely interpreted to the extent that a person skilled in the art can technically understand it.

One means of the present invention is
A lead screw (40) in which one end (41) is connected to a drive source (30), extends in the axial direction, and has a thread formed on the outer circumference.
A nut member (60) screwed into the thread of the lead screw and
A housing base (71) arranged on the other side of the lead screw and
A housing cover (73) located on the other side of the lead screw and fitted inside the housing base is provided.
A first recess (42a) formed inward in the radial direction is provided in the vicinity of the other end (42) of the lead screw.
The first surface (71c) of the housing base and the second surface (73a) of the housing cover form a second recess that is recessed outward in the radial direction.
A plurality of spherical bodies (72) arranged in the circumferential direction are arranged between the first recess and the second recess.
It is a drive device.

According to the drive device having the above configuration, as compared with the conventional configuration using ball bearings, it is not necessary to fix one end of the reed screw by adhesion or caulking, so that it is possible to reduce the assembly man-hours. Become. In addition, the configuration can be configured with a high degree of freedom in design. Further, as compared with the configuration in which the ball is arranged at the tip of the shaft, the size in the axial direction can be reduced, so that the drive device provided with the reed screw can be configured with a small configuration.

In the above drive device, preferably
A small diameter portion (71b) and a large diameter portion (71a) having an inner diameter larger than that of the small diameter portion are formed inside the housing base (71) in the radial direction.
The small diameter portion (71b) has the second surface which is a slope or a curved surface in contact with the spherical body (72).
The housing cover (73) is fitted to the large diameter portion (71a).

According to the drive device having the above configuration, the spherical body is supported by the first recess (42a), the housing base (71) fitted to each other, and the housing cover (73). Can be stably supported.

In the above drive device, preferably
Further has a guide shaft (50) extending substantially parallel to the lead screw.
The nut member (60) has a through hole (62) through which the guide shaft is inserted.

According to the drive device having the above configuration, the nut member can be stably reciprocated along the axial direction of the guide shaft and the lead screw.

In the above drive device, preferably
Further comprising a frame (10) for supporting the lead screw (40) and the housing base (71).
The frame (10) has a through hole (13) into which the housing base (71) is fitted.
The housing base (71) is press-fitted into the through hole (13).

According to the drive device having the above configuration, the housing base can be stably fixed to the frame by press fitting. Also, the housing base can be fixed to the frame without the use of adhesives or welding.

The present invention includes an electronic device including any of the above driving devices.

According to such an electronic device, it is possible to configure an electronic device such as a smartphone, which is easy to assemble, has a low cost, and / or is smaller than a conventional configuration, and includes a drive device provided with a reed screw.

It is an external perspective view of the geared motor of an embodiment. It is sectional drawing of the geared motor of an embodiment. It is an enlarged view of the part A in the cross-sectional view of the geared motor of an embodiment. It is an exploded perspective view of the geared motor of an embodiment. It is an enlarged view of the part B in the exploded perspective view of the geared motor of an embodiment.

One of the features of the geared motor of the present invention is that the nut member screwed into the reed screw supports the end of the reed screw in a configuration in which the motor reciprocates in the axial direction by rotationally driving the reed screw. is there. Specifically, a spherical body (ball) is arranged by providing an axial recess near the end of the lead screw, and the ball is supported by the recess, the housing base, and the housing cover. Is one of the features.

An embodiment of the present invention will be described according to the following configuration. However, the embodiments described below are merely examples of the present invention, and do not limit the technical scope of the present invention. In each drawing, the same components are designated by the same reference numerals, and the description thereof may be omitted. In the following description, the direction in which the output shaft of the motor 20 extends may be described as the "axial direction". The output shaft of the motor 20 and the shaft of the reed screw 40, which is the output shaft of the planetary gear mechanism 30, are coaxial.
1. 1. Embodiment 2. Features of the present invention 3. Supplementary information

<1. Embodiment>
The geared motor of the present embodiment is for driving a camera mounted on an electronic device such as a smartphone to move it back and forth. 1 to 5 are views showing a geared motor of the present embodiment. FIG. 1 is an external perspective view of the entire geared motor of the present embodiment. FIG. 2 is a cross-sectional view of the geared motor. FIG. 3 is an enlarged view of the portion “A” in FIG. FIG. 4 is an exploded perspective view of the geared motor. FIG. 5 is an enlarged view of the portion “B” in FIG.

The geared motor of the present embodiment includes a frame 10, a motor 20, a planetary gear mechanism 30, a lead screw 40, a guide shaft 50, a nut member 60, a housing base 71, a spherical body (ball) 72, and a housing cover 73. To. In the geared motor of the present embodiment, the configuration including the motor 20 and the planetary gear mechanism 30 may be referred to as a "drive source". The geared motor of the present embodiment is a specific example of the "driving device" of the present invention.

<Frame 10>
The frame 10 constitutes the housing of the geared motor of the present embodiment. The frame 10 includes an accommodating portion 11 for accommodating the planetary gear mechanism 30, three through holes 12 for connecting the geared motor to another configuration, and through holes 13 and 14 into which the ends of the lead screws 40 are inserted. Will be done. The frame 10 supports a planetary gear mechanism 30, a lead screw 40, a guide shaft 50, a housing base 71, a spherical body 72, and a housing cover 73.

The accommodating portion 11 is located outside the planetary gear mechanism 30 and covers and accommodates the planetary gear mechanism 30. Inside the accommodating portion 11, the planetary gear mechanism 30 is fixed in position. The through holes 12 are three through holes for connecting a geared motor to another configuration such as a smartphone. A connecting screw or the like is inserted into each of these through holes 12, and the geared motor and other configurations are connected.

The through hole 13 is a through hole that penetrates in a circular shape in the axial direction, and the other end portion 42 of the lead screw 40, the housing base 71, the spherical body 72, and the housing cover 73 are located. At the time of assembly, the lead screw 40 is inserted through the through hole 13. The through hole 14 is a through hole that penetrates in a circular shape in the axial direction, and one end 41 of the lead screw 40 is inserted into the through hole 14.

<Motor 20>
The motor 20 is a well-known stepping motor including a rotor (not shown) including a rotating shaft 20a and a stator (not shown) arranged around the rotor. The motor 20 includes four input terminals 21 protruding outward from the side surface. When a voltage is applied to the input terminal 21, the rotating shaft 20a of the motor 20 rotates. A planetary gear mechanism 30 is connected to the output side of the rotating shaft 20a of the motor 20. When the motor 20 rotates, the planetary gear mechanism 30 operates.

<Planetary gear mechanism 30>
The planetary gear mechanism 30 includes an input sun gear, a planetary gear, a carrier, and a fixed internal gear (all not shown). The planetary gear mechanism 30 is housed in the housing section 11. Since the planetary gear mechanism 30 has a well-known configuration, a specific description thereof will be omitted here. The input sun gear of the planetary gear mechanism 30 is connected to the rotating shaft 20a of the motor 20. The planetary gear mechanism 30 transmits power to the lead screw 40 to rotate it. The planetary gear mechanism 30 is an example of a reduction mechanism, and may be replaced with another reduction mechanism.

<Lead screw 40>
The lead screw 40 is formed in a substantially cylindrical shape that is coaxial with the rotation shaft 20a of the motor 20 and extends in the axial direction, and a feed screw made of, for example, a trapezoidal screw is formed on the outer peripheral surface thereof. The nut member 60 is arranged on the lead screw 40 so as to mesh with the feed screw, and when the lead screw 40 rotates, the nut member 60 moves in the axial direction. When the lead screw 40 rotates in one direction, the nut member 60 moves in one axial direction, and when the lead screw 40 rotates in the opposite direction, the nut member 60 moves in the other axial direction.

One end 41 of the lead screw 40 (the end toward the planetary gear mechanism 30) is connected to the planetary gear mechanism 30. When the planetary gear mechanism 30 that receives the rotational force of the motor 20 operates, the lead screw 40 rotates.

A recess 42a formed inward in the radial direction is provided in the vicinity of the other end 42 (the end opposite to the planetary gear mechanism 30) of the lead screw 40. In other words, the recess 42a is a groove formed in the circumferential direction provided near the end 42 of the lead screw 40. A plurality of spherical bodies 72 arranged in the circumferential direction are arranged in the recess 42a. Further, the other end 42 of the lead screw 40 comes into contact with the housing base 71 and the housing cover 73 via the spherical body 72. The other end 42 of the reed screw 40 is supported by the housing base 71, the sphere 72, and the housing cover 73 so that the reed screw 40 can rotate. The recess 42a is a specific example of the "first recess" of the present invention.

<Housing base 71>
The housing base 71 is arranged radially outside the end 42 of the lead screw 40 and inside the through hole 13 of the frame 10. The housing base 71 is fitted into the through hole 13 of the frame 10. At the time of assembly, the housing base 71 is press-fitted into the through hole 13. The housing base 71 is an annular member and has a through hole inside. The end portion 42 of the lead screw 40 and the spherical body 72 are located in the through hole. The housing base 71 is composed of portions having two inner diameters, large and small, which are referred to as a large diameter portion 71a and a small diameter portion 71b (see FIG. 3). A housing cover 73 is fitted inside the large diameter portion 71a. That is, the housing cover 73 is in contact with the large diameter portion 71a. The small diameter portion 71b has a slope 71c having a predetermined angle with respect to the axial direction, and the slope 71c is in contact with the spherical body 72. The slope 71c forms an internal angle of approximately 45 ° with respect to the axial direction. The slope 71c is a specific example of the "first surface" in the present invention.

The housing base 71 may be fixed by being inserted into the through hole 13 of the frame 10 and adhered or welded. Further, the radial inner slope 71c of the housing base 71 may be a curved surface (R surface) instead of the linear surface as shown in FIG. 3 or the like.

<Housing cover 73>
The housing cover 73 is arranged radially outside the end portion 42 of the lead screw 40 and inside the large diameter portion 71a of the housing base 71. The housing cover 73 is fitted to the large diameter portion 71a of the housing base 71. At the time of assembly, the housing cover 73 is press-fitted into the large diameter portion 71a. The housing cover 73 is an annular member and has a through hole inside. The end portion 42 of the lead screw 40 and the spherical body 72 are located in the through hole. Inside the housing cover 73 in the radial direction, a slope 73a having a predetermined angle with respect to the axial direction is provided, and the slope 73a is in contact with the spherical body 72. The slope 73a forms an internal angle of approximately 45 ° with respect to the axial direction. The slope 73a is a specific example of the "second surface" of the present invention.

The housing cover 73 may be fixed to the housing base 71 by being crimped while being inserted into the large diameter portion 71a of the housing base 71. Alternatively, the housing cover 73 may be fixed to the housing base 71 by being welded or adhered while being inserted into the large diameter portion 71a of the housing base 71.

Further, the radial inner slope 73a of the housing cover 73 may be a curved surface (R surface) instead of the linear surface as shown in FIG. 3 or the like.

<Spherical body 72>
As described above, the spherical body 72 is arranged so as to fit into the recess 42a formed in the end portion 42 of the lead screw 40. Eight spherical bodies 72 are arranged side by side in the circumferential direction around the axis of the lead screw 40. The spherical body 72 has two points in contact with the recess 42a of the lead screw 40, one point in contact with the housing base 71 (71c), and one point in contact with the housing cover 73 (73a). That is, the spherical body 72 is formed by a recess formed by the slope 71a of the housing base 71 and the slope 73a of the housing cover 73 (a specific example of the “second recess” of the present invention) and the recess 42a of the lead screw 40. Placed in between. The spherical body 72, the lead screw 40, the housing base 71, and the housing cover 73 are in point contact with each other. Lubricating oil is applied to the spherical body 72.

The number of spherical bodies 72 may be arranged so as to be an appropriate number according to the sizes of the lead screw 40 and the spherical bodies 72, and it is not always necessary to arrange eight spherical bodies 72. Further, the spherical body 72 may be configured so that the lubricating oil is not applied. In this case, it is preferable that the lubricating oil does not scatter to other parts. Even if the spherical body 72 is not coated with lubricating oil, the spherical body 72 is in point contact with the lead screw 40, the housing base 71, and the housing cover 73, so that excessive friction does not occur.

<Guide shaft 50>
The guide shaft 50 is formed in a substantially cylindrical shape extending in a direction parallel to the axial direction, and is arranged on the side of the lead screw 40. Both ends of the guide shaft 50 are inserted into and fixed through holes formed in the frame 10. Both ends of the guide shaft 50 are formed to have substantially the same size as the through hole of the frame 10, and are press-fitted into the through hole. As a result, the guide shaft 50 is stably fixed to the frame 10.

Instead of press-fitting both ends of the guide shaft 50 into the through holes of the frame 10, both ends of the guide shaft 50 and the frame 10 may be welded or adhered to each other. However, a configuration in which both ends of the guide shaft 50 are press-fitted into the through holes of the frame 10 is preferable in that a step of welding or bonding is not required.

Further, the lead screw 40 may be guided in the axial direction by another configuration instead of the guide shaft 50.

<Nut member 60>
The nut member 60 has through holes 61, 62, and 63. The lead screw 40 is inserted through the through hole 61 of the nut member 60, and the male screw thread of the lead screw 40 is screw-fitted into the female screw thread formed on the inner circumference of the through hole 61. The guide shaft 50 is inserted into the through hole 62, and the nut member 60 reciprocates while being guided in the axial direction in which the guide shaft 50 extends. A camera or the like, which is a drive object driven by a geared motor, is connected to the two through holes 63 formed in the nut member 60 by a connecting tool such as a screw.

The configuration in which the geared motor of the present embodiment is connected to the driving object by using the nut member 60 is merely an example, and the geared motor may be connected to the driving object by other means.

<2. Features of the present invention>
The present invention described above by exemplifying one embodiment has the following features.

In the geared motor of the above embodiment, a plurality of spherical bodies 72 arranged side by side in the recess 42a of the lead screw 40 are arranged on the slope 71c (or curved surface) of the housing base 71 and the slope 73a (or the housing cover 73) of the housing cover 73. It is held by being in contact with the curved surface). When the lead screw 40 rotates, the spherical body 72 rotates, so that the lead screw 40 rotates smoothly. According to this configuration, as compared with the configuration using ball bearings, it is not necessary to fix one end of the lead screw 40 by adhesion or caulking, so that the assembly man-hours can be reduced. In addition, the configuration can be configured with a high degree of freedom in design. Further, as compared with the configuration in which the ball is arranged at the tip of the shaft of the reed screw 40, the size in the axial direction can be reduced, so that the drive device provided with the reed screw 40 is configured in a compact configuration. be able to.

In the geared motor of the above embodiment, the small diameter portion 71b and the large diameter portion 71a are formed inside the housing base 71 in the radial direction, and the small diameter portion 71b has a slope in contact with the spherical body 72, and the large diameter portion 71a has a slope. The housing cover 73 is fitted to the housing cover 73. With this configuration, the spherical body 72 is supported by the recess 42a of the lead screw 40, the housing base 71 and the housing cover 73 that are fitted to each other, and the spherical body 72 can be stably supported. ..

The geared motor of the above embodiment has a guide shaft 50, and the nut member 60 has a through hole 62 through which the guide shaft 50 is inserted. With this configuration, the nut member 60 can be stably reciprocated along the axial direction of the guide shaft 50 and the lead screw 40.

The geared motor of the above embodiment includes a frame 10 and has a housing base 71 press-fitted into a through hole 13 of the frame 10 to be fitted. With this configuration, the housing base 71 is stably fixed to the frame 10.

The geared motor of the embodiment is particularly useful when it is adopted in a portable electronic device such as a smartphone, a tablet device, or a notebook PC. Such an electronic device can be configured to include a drive device that is easy to assemble, low cost, and / or smaller than that of a conventional geared motor.

<3. Supplementary information>
The specific embodiment of the present invention has been described above. The above description is merely an embodiment, and the scope of the present invention is not limited to this one embodiment and is broadly interpreted to a range that can be grasped by those skilled in the art.

In the geared motor of the embodiment, the configuration example in which the motor 20 is a stepping motor has been described, but the motor 20 may be any motor other than the stepping motor.

In the geared motor of the embodiment, the configuration including the planetary gear mechanism 30 has been illustrated and described, but the planetary gear mechanism 30 is not an essential configuration. That is, the configuration may not include the planetary gear mechanism, or may include an acceleration / deceleration mechanism other than the planetary gear mechanism.

The present invention is suitably used as a drive device for driving a camera mounted on a smartphone.

10 ... Frame 11 ... Housing parts 12, 13, 14 ... Through holes 20 ... Motor 20a ... Rotating shaft 21 ... Input terminal 30 ... Planetary gear mechanism 40 ... Lead screw 41 ... End 42 ... End 42a ... Recess 50 ... Guide shaft 60 ... Nut members 61, 62, 63 ... Through holes 71 ... Housing base 71a ... Large diameter portion 71b ... Small diameter portion 72 ... Spherical body 73 ... Housing cover

Claims (5)

A lead screw with one end connected to the drive source, extending axially, and having a thread on the outer circumference.
A nut member screwed into the thread of the reed screw and
A housing base located on the other side of the lead screw,
A housing cover located on the other side of the lead screw and fitted inside the housing base.
A first recess formed inward in the radial direction is provided in the vicinity of the other end of the lead screw.
The first surface of the housing base and the second surface of the housing cover form a second recess that is recessed outward in the radial direction.
A plurality of spherical bodies arranged in the circumferential direction are arranged between the first recess and the second recess.
Drive device. The housing base has a small diameter portion and a large diameter portion having an inner diameter larger than that of the small diameter portion on the inner side in the radial direction.
The small diameter portion has the second surface which is a slope or a curved surface in contact with the spherical body.
The housing cover is fitted to the large diameter portion.
The drive device according to claim 1. Further has a guide shaft extending substantially parallel to the lead screw.
The nut member has a through hole through which the guide shaft is inserted.
The drive device according to claim 1 or 2. Further provided with the lead screw and a frame supporting the housing base.
The frame has a through hole into which the housing base fits.
The housing base is press-fitted into the through hole.
The drive device according to any one of claims 1 to 3. An electronic device including the drive device according to any one of claims 1 to 4.

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