JP2021025592A - Driving device - Google Patents

Abstract

To provide a small driving device which can be incorporated into a spall installation space.SOLUTION: A driving device 1 includes: a frame 10 having a fixing part 13 fixed to a smartphone body 3; a lead screw 30 rotatably supported by the frame 10; a motor 20 which is connected to the lead screw 30 and rotates the lead screw 30; and a nut 40 which engages with the lead screw 30. The lead screw 30 has: a thread part 61 extending in a spiral form along a Z direction; and a cylindrical surface 65 located adjacent to the thread part 61 and extending in a spiral form along the Z direction. The nut 40 has: a screw groove part 71 extending in a spiral form along the Z direction; and a cylindrical surface 75 located adjacent to the screw groove part 71 and extending in a spiral form along the Z direction. The screw groove part 71 of the nut 40 threadedly engages with the thread part 61 of the lead screw 30, and the cylindrical surface 75 of the nut 40 contacts with the cylindrical surface 65 of the lead screw 30.SELECTED DRAWING: Figure 1

Description

The present invention relates to a drive device and relates to a drive device that moves a drive object with respect to a reference member in an axial direction.

In recent years, electronic devices such as laser irradiation type disk devices and smartphones are increasingly equipped with a mechanism (driving device) for moving a lens, a camera, or the like as needed. For example, in a smartphone equipped with a camera, a function of moving the camera in and out of the smartphone body may be added. In order to move a driving object such as a lens or a camera, it is conceivable to use, for example, a driving device using a lead screw (see, for example, Patent Document 1).

In a drive device using such a lead screw, a drive object such as a lens or a camera is fixed to a movable part attached to the lead screw, and the drive object is moved in the axial direction by rotating the lead screw with a motor. It is designed to move to. The movable portion slides on a guide shaft extending in parallel with the lead screw, and the movable portion is supported by the guide shaft to regulate the movement of the movable portion in an unintended direction.

However, in such a conventional drive device, since it is necessary to arrange the guide shaft adjacent to the lead screw, there is a problem that the installation space thereof becomes large. With the recent miniaturization of electronic devices, there is an increasing demand for drive devices that can be incorporated into smaller installation spaces.

Japanese Unexamined Patent Publication No. 2018-13795

The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide a small drive device that can be incorporated into a small installation space.

According to one aspect of the present invention, there is provided a small drive device that can be incorporated into a small installation space. This drive device is used to move the object to be driven along the axial direction with respect to the reference member. The drive device includes a frame having a fixing portion fixed to the reference member, a lead screw extending along the axial direction and rotatably supported by the frame, and a lead screw connected to the lead screw. A motor for rotating the lead screw and a nut for engaging with the lead screw are provided. The lead screw has a first screw portion that spirally extends along the axial direction and a cylindrical surface that spirally extends along the axial direction adjacent to the first screw portion. The nut is a second threaded portion that extends spirally along the axial direction, and is a second threaded portion screwed into the first threaded portion of the lead screw and the second threaded portion. Adjacent to the lead screw, it has a contact surface that extends spirally along the axial direction and abuts on the cylindrical surface of the lead screw.

In such a configuration, the first threaded portion of the lead screw serves to move the nut along the axial direction by engaging with the second threaded portion of the nut, and the cylindrical surface of the lead screw It has the role of supporting the nut by contact with the contact surface of the nut and restricting the movement of the nut in an unintended direction. That is, since one reed screw has both a role of moving the nut in the axial direction and a role of supporting the nut, it is not necessary to separately install a guide shaft, and the installation space required for the drive device is reduced. can do.

It is preferable that the cross section when the nut is cut on an arbitrary plane including the central axis of the nut includes at least three cross-sectional portions of the second threaded portion. According to such a configuration, the first threaded portion of the lead screw and the second threaded portion of the nut are engaged at at least three points in the cross section, so that the nut can be moved more stably along the axial direction. Can be made to.

Further, it is preferable that the cross section when the nut is cut on an arbitrary plane including the central axis of the nut includes at least three cross-sectional portions of the contact surface. According to such a configuration, since the contact surface of the nut contacts the cylindrical surface of the reed screw at at least three points in the cross section, the nut can be supported more stably by the cylindrical surface of the reed screw. ..

In order to move the nut more stably along the axial direction, it is preferable that the first threaded portion of the lead screw is composed of a plurality of threads extending along the axial direction. In this case, the second threaded portion of the nut may be formed by a thread groove having the same number of threads as the number of threads forming the first threaded portion of the lead screw.

In the present invention, the first threaded portion of the lead screw has a role of moving the nut along the axial direction by engaging with the second threaded portion of the nut, and the cylindrical surface of the lead screw is the nut. It has the role of supporting the nut by contact with the contact surface and restricting the movement of the nut in an unintended direction. That is, since one reed screw has both a role of moving the nut in the axial direction and a role of supporting the nut, it is not necessary to separately install a guide shaft, and the installation space required for the drive device is reduced. can do.

FIG. 1 is a front view showing a drive device according to an embodiment of the present invention together with a drive object. FIG. 2 is a perspective view of the drive device of FIG. FIG. 3 is a perspective view showing a lead screw in the drive device of FIG. FIG. 4 is a perspective view showing a nut in the drive device of FIG. FIG. 5 is a vertical cross-sectional view of the nut of FIG. FIG. 6 is a partial cross-sectional view of a lead screw and a nut in the drive device of FIG.

Hereinafter, embodiments of the drive device according to the present invention will be described in detail with reference to FIGS. 1 to 6. In FIGS. 1 to 6, the same or corresponding components are designated by the same reference numerals, and duplicate description will be omitted. Further, in FIGS. 1 to 6, the scale and dimensions of each component may be exaggerated or some components may be omitted.

FIG. 1 is a front view showing a drive device 1 according to an embodiment of the present invention together with a camera unit 2 as a drive object, and FIG. 2 is a perspective view of the drive device 1 of FIG. The drive device 1 in the present embodiment is provided inside, for example, the smartphone body 3, and the camera unit 2 including the image pickup lens and the image sensor can be moved in the Z direction with respect to the smartphone body 3 as a reference member. it can. For example, the drive device 1 moves the camera unit 2 in the + Z direction to project from the smartphone body 3 at the time of shooting, and moves the camera unit 2 in the −Z direction to accommodate the inside of the smartphone body 3 after the shooting is completed. Can be done. FIG. 1 shows a state in which the camera unit 2 is not used, and in this state, the camera unit 2 is housed inside the smartphone main body 3. In the present embodiment, for convenience, the + Z direction in FIG. 1 is referred to as "up" or "upward", and the −Z direction is referred to as "down" or "downward".

As shown in FIGS. 1 and 2, the drive device 1 includes a frame 10 fixed to the smartphone body 3, a stepping motor 20 attached to the frame 10, a gearbox 22 attached to the stepping motor 20, and a Z direction. It has a lead screw 30 extending in the (axial direction) and a nut 40 engaging with the lead screw 30. The nut 40 is connected to the camera unit 2 by a movable member 50.

The frame 10 is formed between the upper flange portion 11, the lower flange portion 12, the fixing portion 13 in which the screw hole 13A through which the fixing screw is inserted is formed, and the upper flange portion 11 and the lower flange portion 12. It has a back plate portion 16 extending by. The lead screw 30 is attached to the upper flange portion 11 and the lower flange portion 12 of the frame 10 via the upper bearing 31 and the lower bearing 32, respectively, and is rotatably supported by the frame 10. As will be described later, a nut 40 is engaged with the lead screw 30, and one side surface (side surface on the −Y direction side) of the nut 40 is in contact with the back plate portion 16.

The frame 10 is fixed to the smartphone body 3 by inserting a screw (not shown) into the screw hole 13A of the fixing portion 13 of the frame 10 and screwing this screw into the smartphone body 3. These fixing portions 13 are provided so as to extend from each of the upper flange portion 11 and the lower flange portion 12. As shown in FIG. 2, the gearbox 22 is fixed to the lower flange portion 12 of the frame 10 by a screw 23.

FIG. 3 is a perspective view showing the lead screw 30 of FIG. As shown in FIG. 3, a spur gear 33 is attached to the lead screw 30, and the spur gear 33 is housed in the gearbox 22. In the gearbox 22, in addition to the spur gear 33 of the lead screw 30, a planetary gear mechanism (not shown) connected to the output shaft of the stepping motor 20 is housed. The planetary gear mechanism slows down the rotation of the stepping motor 20. This planetary gear mechanism is also connected to a spur gear 33 attached to the lead screw 30, and the lead screw 30 is connected to the output shaft of the stepping motor 20 via the spur gear 33 and the planetary gear mechanism. Therefore, when the stepping motor 20 is driven, the rotation of the output shaft of the stepping motor 20 is transmitted to the lead screw 30 via the planetary gear mechanism and the spur gear 33, and the lead screw 30 rotates.

As shown in FIG. 3, the lead screw 30 has a thread portion 61 (first thread portion) spirally extending along the Z direction (axial direction) and a thread portion 61 adjacent to the thread portion 61 along the Z direction. It has a cylindrical surface 65 extending spirally. The threaded portions 61 extend spirally at intervals in the Z direction. That is, the pitch of the thread portion 61 is larger than the width of the thread portion 61 in the Z direction. In the present embodiment, two of the general six-thread lead screw threads are deleted, a cylindrical surface 65 is placed on the deleted threads, and the remaining four threads are screwed. It is used as Yamabe 61. As described above, the thread portion 61 in the present embodiment is composed of four threads 62A, 62B, 62C, and 62D.

FIG. 4 is a perspective view of the nut 40, and FIG. 5 is a vertical sectional view of the nut 40. As shown in FIGS. 4 and 5, the nut 40 has a nut body 45 having a substantially rectangular parallelepiped shape, and an engaging hole 46 penetrating the nut body 45 along the Z direction in the center of the nut body 45. Is formed. Inside the engaging hole 46, a thread groove portion 71 (second threaded portion) spirally extending along the Z direction and a cylindrical surface adjacent to the thread groove portion 71 spirally extending along the Z direction ( A contact surface) 75 is formed. The threaded grooves 71 extend spirally at intervals in the Z direction. That is, the pitch of the thread groove portion 71 is larger than the width of the thread groove portion 71 in the Z direction. The thread groove portion 71 is formed corresponding to the thread portion 61 of the lead screw 30, and the cylindrical surface 75 is formed corresponding to the cylindrical surface 65 of the lead screw 30. That is, the thread groove portion 71 in the present embodiment is composed of four thread grooves 72A, 72B, 72C, 72D, and these thread grooves 72A, 72B, 72C, 72D are the thread portions 61 of the lead screw 30. It is designed to be screwed into the threads 62A, 62B, 62C, and 62D, respectively.

FIG. 6 is a partial cross-sectional view showing the lead screw 30 and the nut 40. As shown in FIG. 6, the threads 62A, 62B, 62C, 62D of the thread portion 61 of the lead screw 30 are screwed into the thread grooves 72A, 72B, 72C, 72D of the thread groove portion 71 of the nut 40. The cylindrical surface 65 of the lead screw 30 and the cylindrical surface 75 of the nut 40 are in contact with each other. The threads 62A, 62B, 62C, 62D of the lead screw 30 and the corresponding thread grooves 72A, 72B, 72C of the nut 40 so that the nut 40 can rotate relative to the lead screw 30 and move in the axial direction. A slight gap G is formed along the radial direction between the and 72D. Due to the presence of this gap G, it is conceivable that the nut 40 rattles in the radial direction when rotating with respect to the lead screw 30, but in the present embodiment, the cylindrical surface 65 of the lead screw 30 and the cylindrical surface 75 of the nut 40 And are in contact with each other, and the cylindrical surface 65 of the lead screw 30 supports the nut 40, so that such rattling is suppressed.

In such a configuration, when the stepping motor 20 is driven, the rotation of the output shaft of the stepping motor 20 is transmitted to the lead screw 30 via the planetary gear mechanism and the spur gear 33 in the gearbox 22, and the lead screw 30 rotates. .. When the lead screw 30 rotates because the threads 62A, 62B, 62C, 62D of the thread portion 61 of the lead screw 30 and the thread grooves 72A, 72B, 72C, 72D of the thread groove portion 71 of the nut 40 are screwed together. The nut 40 also tries to rotate, but since the side surface of the nut body 45 of the nut 40 is in contact with the back plate portion 16 of the frame 10, the rotation of the nut 40 is restricted by the back plate portion 16 of the frame 10. As a result, the nut 40 moves in the Z direction as the lead screw 30 rotates.

At this time, as described above, since the cylindrical surface 65 of the lead screw 30 and the cylindrical surface 75 of the nut 40 are in contact with each other, the nut 40 is supported by the cylindrical surface 65 of the lead screw 30. As a result, rattling that may occur due to the gap G between the threads 62A, 62B, 62C, 62D of the lead screw 30 and the corresponding thread grooves 72A, 72B, 72C, 72D of the nut 40 is suppressed.

When the stepping motor 20 is driven in this way, the reed screw 30 rotates and the nut 40 moves in the Z direction, and the movable member 50 and the camera unit 2 attached to the movable member 50 also move in the Z direction accordingly. Will be done.

As described above, in the present embodiment, the thread portion 61 of the lead screw 30 has a role of moving the nut 40 along the Z direction by engaging with the thread groove portion 71 of the nut 40, and the lead screw 30 has a role of moving the nut 40. The cylindrical surface 65 has a role of supporting the nut 40 by abutting the nut 40 with the cylindrical surface 75 and restricting the movement of the nut 40 in an unintended direction. That is, since one reed screw 30 has a role of moving the nut 40 in the axial direction and a role of supporting the nut 40, it is not necessary to separately install a guide shaft, and the drive device 1 is required. The installation space can be reduced. Further, it is not necessary to consider the parallelism between the lead screw 30 and the guide shaft when assembling the drive device 1.

In the above-described embodiment, the example in which the thread portion 61 of the lead screw 30 is formed by the four threads 62A, 62B, 62C, 62D has been described, but the number of threads constituting the thread portion 61 is large. It is not limited to this. For example, the thread portion 61 may be formed by one thread, but in order to stably move the nut 40 along the axial direction, the thread portion 61 is formed by a plurality of threads. Is preferable. In this case, the thread groove portion 71 of the nut 40 is composed of a thread groove having the same number of threads as the thread number of the thread portion 61 of the lead screw 30.

Further, the cross section of the nut 40 shown in FIG. 6 includes three cross-sectional portions of the thread groove portion 71 (one on the −X direction side and two on the + X direction side with respect to the central axis of the nut 40). In this way, the cross section when the nut 40 is cut on an arbitrary plane including the central axis of the nut 40 is configured to include at least three cross-sectional portions of the thread groove portion 71, so that the thread portion of the lead screw 30 is formed. Since the 61 and the threaded groove 71 of the nut 40 are engaged at at least three points in the cross section, the nut 40 can be moved more stably along the axial direction.

The cross section of the nut 40 shown in FIG. 6 includes three cross-sectional portions of the cylindrical surface 75 (two on the −X direction side and one on the + X direction side with respect to the central axis of the nut 40). As described above, the cylindrical surface 75 of the nut 40 is formed by configuring the cross section of the nut 40 when the nut 40 is cut on an arbitrary plane including the central axis of the nut 40 so as to include at least three cross-sectional portions of the cylindrical surface 75. Since the nut 40 is brought into contact with the cylindrical surface 35 of the lead screw 30 at at least three points in the cross section, the nut 40 can be supported more stably by the cylindrical surface 35 of the lead screw 30.

Further, in the above-described embodiment, the first screw portion of the lead screw 30 is a screw thread portion 61 composed of threads 62A, 62B, 62C, 62D protruding outward in the radial direction from the cylindrical surface 65. An example has been described in which the second threaded portion of the nut 40 is a threaded groove portion 71 composed of threaded grooves 72A, 72B, 72C, 72D recessed inward in the radial direction from the cylindrical surface 75, but the threaded portion and the threaded groove portion have been described. You may swap the relationship with. That is, the first screw portion of the lead screw 30 is a screw groove portion composed of a plurality of screw grooves recessed inward in the radial direction from the cylindrical surface 65, and the second screw portion of the nut 40 is radially outward from the cylindrical surface 75. It may be a screw thread portion composed of a plurality of threads protruding from the screw thread.

In the above-described embodiment, the rotation of the nut 40 is regulated by the back plate portion 16 of the frame 10, but the method of restricting the rotation of the nut 40 is not limited to this, and the nut 40 can be regulated by any method. Rotation can be regulated.

In the above-described embodiment, an example in which the stepping motor 20 is used to rotate the reed screw 30 has been described, but the motor for rotating the reed screw 30 is not limited to the stepping motor. However, in order to accurately control the amount of movement of the camera unit 2, it is preferable to use a stepping motor as the motor for rotating the lead screw 30.

Further, in the above-described embodiment, an example in which a planetary gear mechanism is used as a gear mechanism for decelerating the rotation of the output shaft of the stepping motor 20 has been described, but the gear mechanism for decelerating the rotation of the output shaft of the stepping motor 20 is arbitrary. Gear mechanism can be used.

Although the preferred embodiment of the present invention has been described so far, it goes without saying that the present invention is not limited to the above-described embodiment and may be implemented in various different forms within the scope of the technical idea.

1 Drive unit 2 Camera unit 3 Smartphone body 10 Frame 11 Upper flange part 12 Lower flange part 13 Fixed part 16 Back plate part 20 Stepping motor 22 Gearbox 30 Lead screw 31 Upper bearing 32 Lower bearing 33 Spur gear 35 Cylindrical surface 40 Nut 45 Nut body 46 Engagement hole 50 Movable member 61 Thread part (first thread part)
62A, 62B, 62C, 62D Thread 65 Cylindrical surface 71 Thread groove (second thread)
72A, 72B, 72C, 72D Thread groove 75 Cylindrical surface (contact surface)

Claims (5)

A drive device that moves an object to be driven along the axial direction with respect to a reference member.
A frame having a fixing portion fixed to the reference member and
A reed screw that extends along the axial direction and is rotatably supported by the frame.
A motor connected to the reed screw and rotating the reed screw,
With a nut that engages with the reed screw
The lead screw
A first threaded portion that spirally extends along the axial direction,
It has a cylindrical surface that is adjacent to the first threaded portion and extends spirally along the axial direction.
The nut
A second threaded portion that spirally extends along the axial direction, and a second threaded portion that is screwed into the first threaded portion of the reed screw.
Adjacent to the second threaded portion, it has a contact surface that extends spirally along the axial direction and abuts on the cylindrical surface of the reed screw.
Drive device. The driving device according to claim 1, wherein the cross section when the nut is cut on an arbitrary plane including the central axis of the nut includes at least three cross-sectional portions of the second screw portion. The driving device according to claim 1 or 2, wherein the cross section when the nut is cut on an arbitrary plane including the central axis of the nut includes at least three cross-sectional portions of the contact surface. The driving device according to any one of claims 1 to 3, wherein the first threaded portion of the lead screw is composed of a plurality of threads extending along the axial direction. The drive according to claim 4, wherein the second threaded portion of the nut is formed by a thread groove having the same number of threads as the number of threads of the thread forming the first threaded portion of the lead screw. apparatus.

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