Lens driving mechanism, lens device, and imaging apparatus

Abstract

To provide a lens driving mechanism that is small-sized and can perform stable driving against an impact.SOLUTION: A lens driving mechanism has: a holding member that holds a lens, and is movable in an optical axis direction; a feed screw that extends in the optical axis direction; driving means that rotates the feed screw; a rack that has a meshing part including a first portion meshing with the feed screw, an opposite part having a second portion arranged opposite to the first portion with the feed screw therebetween, and an attachment part connected to the holding member; a first elastic member that urges the meshing part against the feed screw with a first force; and a second elastic member that urges a first contact part of the meshing part and a second contact part of the opposite part with a second force so that the contact parts press each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a lens driving mechanism, a lens device, and an imaging device. [Background technology]

[0002] With the demand for smaller optical devices such as digital still cameras and digital video cameras, there is also a demand for smaller lens barrels to be mounted on them. In addition, there is a demand for more energy-efficient lens barrels to reduce the size of batteries and extend the available shooting time. Furthermore, in order to move the lens holding frame that holds the lens in the optical axis direction, many of these optical instruments employ a movement mechanism that uses a torsion coil spring to bias a rack against a feed screw connected to the motor shaft. Patent Document 1 discloses a configuration in which a motor and rack are used in a lens barrel to move a lens holding frame in the optical axis direction, and teeth are provided opposite the main teeth to clamp a feed screw in order to prevent shaking and abnormal noise during operation, and the teeth are connected to the rack body at a connection part. Patent Document 2 discloses a configuration in which the rack is divided into two parts so as to reduce the biasing force of the rack against the feed screw in order to reduce the load torque of the motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-158069 A [Patent Document 2] JP 2014-194486 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a rack structured to sandwich the feed screw between the main teeth and the pinching teeth, the meshing between the main teeth and the pinching teeth with respect to the feed screw is released by an impact such as a fall, causing the rack to shift in position, resulting in a disturbance or blurring of the captured image. If a strong urging force as in Patent Document 1 is applied between the rack and the feed screw to prevent the teeth from jumping, the friction between the two increases, increasing the load on the motor, hindering power saving and leading to an increase in the size of the lens barrel. On the other hand, in a rack structured such that only the urging main teeth engage with the feed screw in a normal state where no impact is applied, when an impact is applied, the counter teeth arranged on the opposite side of the main teeth with respect to the axis of the feed screw engage with the threads of the feed screw to prevent the rack from shifting in the axial direction of the feed screw. However, when only the main teeth contact the feed screw, in order to stabilize the movement of the rack, it is necessary to increase the force urging the main teeth to the feed screw, which increases the load on the motor, hinders power saving and leads to an increase in the size of the lens barrel. An object of the present invention is to provide a lens driving mechanism that is small and capable of performing stable driving against impact. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, the lens driving mechanism of the present invention is characterized in having a holding member that holds a lens and is movable in the optical axis direction, a feed screw extending in the optical axis direction, a driving means that rotates the feed screw, a rack having an engagement portion with a first portion that engages with the feed screw, an opposing portion having a second portion arranged opposite the first portion across the feed screw, and an attachment portion connected to the holding member, a first elastic member that urges the engagement portion against the feed screw with a first force, and a second elastic member that urges the first abutment portion of the engagement portion and the second abutment portion of the opposing portion so as to press them against each other with a second force. Effect of the Invention

[0006] According to the present invention, it is possible to provide a lens driving mechanism that is small in size and capable of performing stable driving against impacts. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a diagram showing a connection configuration between the lens barrel and a camera device according to the present invention. [Diagram 2] 4A and 4B are configuration diagrams of a focus driving unit and a focus moving group. [Diagram 3] 1A and 1B are enlarged plan views showing the molded and used states of the rack. [Figure 4] 11 is a side view showing a restricting shape of the rack in the optical axis direction. FIG. [Diagram 5] 11(a) to 11(c) are views taken along arrows showing restricting shapes for restricting the opening and closing directions of the rack. [Figure 6] 4A and 4B are enlarged plan views showing the engagement between the feed screw and the rack. [Figure 7] 13(a) to 13(c) are side views illustrating the opening operation of the rack. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. EXAMPLES

[0009] Hereinafter, a lens driving mechanism according to an embodiment of the present invention will be described with reference to Figs. 1 to 7. In this embodiment, an interchangeable lens is described as an example, but an imaging device with an integrated lens may also be used. In addition, although a number of features are described in this embodiment, not all of these features are necessarily required, and a number of features may be combined as desired. Furthermore, in the attached drawings, the device according to this embodiment is drawn at a scale different from the actual one in order to facilitate understanding, and the same or similar components are given the same reference numbers, and duplicated explanations will be omitted.

[0010] FIG. 1 is a diagram showing the connection configuration of an imaging device 300 including a lens device 100 and a camera device 200 according to the present invention. The lens device 100 has a lens mount 101, a lens CPU 102, and a lens operation member 103. The lens mount 101 mechanically connects the lens device 100 to the camera device 200. The lens CPU 102 controls the lens device 100, communicates with the camera device 200, and controls functions implemented in the camera device 200. The lens operation member 103 operates, selects, decides, and controls various functions of the lens device 100.

[0011] The lens device 100 also has an operation detection means 104 that detects the operation direction and operation amount of a function ring, which is a rotary operation member (not shown). The operation detection means 104 is, for example, a photointerrupter (not shown), and detects the operation direction and operation amount of the function ring by detecting light reception and light blocking according to a rectangular wave shape (not shown) provided on the inner diameter of the function ring.

[0012] The lens device 100 also includes a focus driving unit 106, a zoom driving unit 107, and an aperture driving unit 108. The focus driving unit 106 is connected to the first lens group 1 as a focus lens group shown in FIG. 2, and changes the focal distance of the lens device 100 by moving the focus lens group in the optical axis direction according to the operation direction and operation amount of a focus ring (not shown). The zoom driving unit 107 is connected to the zoom lens group (not shown), and changes the focal length of the lens device 100 and changes the angle of view by moving the zoom lens group in the optical axis direction according to the operation direction and operation amount of a zoom ring (not shown). The aperture driving unit 108 is connected to an aperture diaphragm (not shown), and drives the aperture diaphragm in response to the operation of the camera device 200, thereby adjusting the amount of light incident on an image sensor (not shown) of the camera device 200.

[0013] The lens device 100 also has a function assignment means 109, a lens memory device 110, and a function change means 111, which are associated with the function ring. The function assignment means 109 is a means for assigning the above-mentioned various functions to the function ring. The lens memory device 110 is a memory device that stores a preset priority of function assignments for automatically connecting functions to the function ring. The function change means 111 is a means for changing the function assigned to the function ring to another function.

[0014] Next, the configuration of the camera device 200 will be described. The camera device 200 has a camera mount 201, a camera CPU 202, a power operation unit 203, a camera operation member 204, a display means 205, and a camera storage device 206. The camera mount 201 is mechanically connected to the lens mount 101 of the lens device 100. The camera CPU 202 controls and communicates with the camera device 200, and controls and communicates with the lens device 100. The power operation unit 203 operates the ON / OFF of the power supply to energize the camera device 200. The camera operation member 204 operates various functions of the camera device 200, and performs operations such as selecting various functions, deciding, canceling, and releasing. The display means 205 displays various settings of the camera device 200 and captured images. The camera storage device 206 stores various settings of the camera device 200 and captured images.

[0015] 2(a) and (b) are diagrams showing a schematic configuration of the focus unit in this embodiment. A focus motor 50, which is a focus driving means 106, is fixed to a fixed lens barrel (not shown) of the lens device 100. A rack 20 connected to a holding member 10 supporting a first lens group (focus lens group) 1 is engaged with a feed screw 51, which is fixed coaxially to the rotation shaft of the focus motor 50 and extends in the optical axis direction. As the focus motor 50 rotates, the driving force of the focus motor 50 is transmitted to the holding member 10 via the rack 20, and the first lens group 1 is moved in the optical axis direction. The first lens group 1 is a focus lens group and is supported by a holding member 10. The holding member 10 has support portions 11 and 12 that are slidably supported by two guide bars 2 and 3, thereby allowing the photographing optical system to move in the optical axis direction.

[0016] The rack 20 has an attachment portion 21, and an engagement portion 24 and an opposing portion 25 shown in Fig. 3. The attachment portion 21 is a structure for holding the rack 20 on the holding member 10, and has a rotating shaft 22 and a tapered portion 23 shown in Fig. 5. The rack 20 is made of, for example, POM resin (polyacetal resin), PC (polycarbonate), or the like.

[0017] The retaining member 10 and the guide bars 2 and 3, the retaining member 10 and the rack 20, and the rack 20 and the feed screw 51 are engaged with each other with some play. The backlash caused by the engagement play such as fitting or meshing between these members is biased by the torsion coil spring 30. The torsion coil spring (first elastic member) 30 has a coil portion 31 and arm portions 32 and 33. A sandwiching spring (second elastic member) 40 is attached to the rack 20, and applies a biasing force so that the main teeth (first portion, first gear teeth) 24a and the opposing teeth (second portion, second gear teeth) 25a sandwich the feed screw 51. The sandwiching spring 40 has arms 41 and 42.

[0018] The focus motor 50 is a driving means (actuator) that moves the first lens group 1, which is a focus lens group, in the optical axis direction to perform a focusing operation. A feed screw 51 rotated by the focus motor 50 engages with a rack 20 installed on a holding member 10 that is guided and supported so as to be movable in the optical axis direction. When the focus motor 50 rotates, the holding member 10 moves in the optical axis direction. The feed screw 51 is coaxial with the rotation axis of the focus motor 50 and is arranged parallel to the optical axis. The feed screw 51 is made of, for example, SUS, iron, etc.

[0019] The coil portion 31 of the torsion coil spring 30 is held by the mounting portion 21 of the rack 20, and is rotatably supported by a rack holding portion constituted by the first bearing portion 13 and the second bearing portion 14 of the holding member 10. By inserting the rotating shaft 22 into the first bearing portion 13 and the tapered portion 23 into the second bearing portion 14, the rack 20 is supported by the holding member 10 so as to be immovable in the optical axis direction and rotatable about the axes of the first bearing portion 13 and the second bearing portion 14. The torsion coil spring 30 moves the rack 20 in the rack holding portion in a direction in which the tapered portion 23 is pressed against the second bearing portion 14, and the rack 20 is positioned in the optical axis direction with respect to the rack holding portion.

[0020] FIG. 3 is an enlarged plan view of the rack 20 and the sandwiching spring 40. FIG. 3(a) shows the molded state of the rack 20, in which the facing portion 25 and the mounting portion 21 are connected to each other by the elastically deformable connecting portion 27. FIG. 3(a) also shows the shape of the connecting portion 27 molded during manufacturing, in a state in which the elastic force of the connecting portion 27 is not applied in any direction (also described as the natural state of the connecting portion 27), and in which the meshing portion 24 and the facing portion 25 are separated from each other. The connecting portion 27 extends from the meshing portion 24 side of the mounting portion 21 to the facing portion 25, centered on the axial direction of the feed screw 51, so as to surround 25% or more of the outer circumference of the mounting portion 21. By configuring the connecting portion 27 in this way, the connecting portion 27 can be configured long in a small space, and by making the deformable region of the connecting portion 27 long, the stress applied to the connecting portion 27 when the meshing portion 24 and the facing portion 25 are closed so as to approach each other can be distributed over a wide region.

[0021] As described later, the rack 20 is provided with a protrusion (convex portion) 28 on the mounting portion 21 side of the meshing portion 24 toward the opposing portion 25, and a recess 29 on the mounting portion 21 side of the opposing portion 25 facing the meshing portion 24. The protrusion 28 and the recess 29 are configured to face each other and fit together. For example, when molding the rack 20 molded from resin, it is necessary to maintain the strength of the mold corresponding to the closest portion while the closest portions of the protrusion 28 and the recess 29 are separated to a certain extent, and to enable stable manufacturing. For this reason, it is necessary to configure the meshing portion 24 and the opposing portion 25 so that they can be molded in a state where they are widely open, and so that they can be used in a state where they are close to each other to a predetermined distance when used. On the other hand, by configuring the connection portion 27 to have a long deformable region as described above, it is possible to mold the meshing portion 24 and the opposing portion 25 in a state where they are widely open.

[0022] Main teeth 24a are formed on the opposing portion 25 side of meshing portion 24 of rack 20, and main teeth 24a engage with the threads of feed screw 51 and receive the driving force of focus motor 50 from feed screw 51. Surface 24b on the opposite side to opposing portion 25 of meshing portion 24 functions as an engagement surface with which arm portion 32 of torsion coil spring 30 and arm portion 41 of sandwiching spring 40 engage.

[0023] Opposing teeth 25a are formed on the meshing portion 24 side of the opposing portion 25, and the opposing teeth 25a are configured to be able to engage with the feed screw 51. A surface 25b on the opposite side of the meshing portion 24 of the opposing portion 25 functions as a locking surface that locks the arm portion 42 of the clamping spring 40. Although the opposing teeth 25a are formed in this embodiment, they may be a flat surface configured to have a certain distance from the feed screw 51 when the main teeth 24a are engaged with the feed screw 51 in the state shown in FIG. 3(b). By setting the flat surface opposite the main teeth 24a, it is possible to prevent the main teeth 24a and the feed screw 51 from being spaced apart by more than a predetermined distance.

[0024] The main tooth 24a is pressed against the feed screw 51 by a first biasing force (first force) due to the biasing force of the torsion coil spring 30. The main tooth 24a and the opposing tooth 25a are in a positional relationship in which the main contact surfaces (first contact parts) 26a, 26b and the sub contact surfaces (second contact parts) 26c, 26d, which will be described later with reference to FIG. 5, are in contact with each other due to the second biasing force (second force) of the sandwiching spring 40, and the feed screw 51 is sandwiched between them. However, in a normal use state, the opposing tooth 25a and the feed screw 51 do not come into contact with each other and have play. Therefore, the driving force due to the rotation of the feed screw 51 is transmitted to the holding member 10 via the main tooth 24a, and the holding member 10 is moved in the optical axis direction. The first biasing force of the torsion coil spring 30 is smaller than the second biasing force of the sandwiching spring 40. More specifically, the first biasing force of torsion coil spring 30 is smaller than the biasing force obtained by subtracting the reaction force (third force) generated at connection portion 27 from the second biasing force of sandwiching spring 40.

[0025] 3(b) shows the usage state with the sandwiching spring 40 incorporated into the rack 20. The facing portion 25 is molded in a state where it is farther away from the meshing portion 24 than in the usage state. By incorporating the sandwiching spring 40 into the rack 20, a second biasing force acts in a direction in which the meshing portion 24 and the facing portion 25 approach each other, and the facing portion 25 moves relative to the meshing portion 24 to a position in the usage state, and the meshing portion 24 and the facing portion 25 close so as to be closest to each other.

[0026] Fig. 4 is a view seen from the direction of the arrow X shown in Fig. 3(b). A protrusion 28 is provided on the attachment portion 21 side of the meshing portion 24 toward the opposing portion 25, and a recess 29 is provided on the attachment portion 21 side of the opposing portion 25 facing the meshing portion 24. In other words, the protrusion 28 protruding in the direction of the feed screw 51 is provided on the meshing portion 24 side, and the recess 29 corresponding to the protrusion 28 is provided on the opposing portion 25 side. The protrusion 28 has a surface 28a and a surface 28b perpendicular to the axial direction of the feed screw 51. The recess 29 has a surface 29a facing the surface 28a and a surface 29b facing the surface 28b. When a force is generated that causes a misalignment between the main tooth 24a and the opposing tooth 25a in the axial direction of the feed screw 51, surfaces 28a and 29a, or surfaces 28b and 29b, come into contact with each other, suppressing the relative movement (misalignment) between the main tooth 24a and the opposing tooth 25a in the axial direction of the feed screw 51. In the embodiment, the projection 28 is provided on the meshing portion 24 and the recess 29 is provided on the facing portion 25, but the present invention is not limited to this. It is sufficient that the projection 28 is provided on one of the meshing portion 24 and the facing portion 25 and the recess 29 is provided on the other of the meshing portion 24 and the facing portion 25.

[0027] 5 is a diagram showing a shape related to the restriction of the opening and closing direction of the rack 20. (a) is a view of the rack 20 from the axial direction of the rotating shaft 22, (b) is a view of the meshing portion 24 from the direction of the arrow Y in (a), and (c) is a view of the opposing portion 25 from the direction of the arrow Z in (a). The meshing portion 24 has three abutment surfaces that abut against the opposing portion 25. Two main abutment surfaces (eleventh abutment surface) 26a are provided apart from each other in the axial direction of the feed screw 51, and a main abutment surface (twelfth abutment surface) 26b is provided apart from the two main abutment surfaces 26a in a direction perpendicular to the axial direction of the feed screw 51. In the axial direction of the feed screw 51, the main abutment surface 26b is provided between the two main abutment surfaces 26a.

[0028] There are three abutment surfaces on the opposing portion 25, and two sub-abutment surfaces (21st abutment surfaces) 26c are provided at positions corresponding to the main abutment surfaces 26a. A sub-abutment surface (22nd abutment surface) 26d is provided at a position corresponding to the main abutment surface 26b. The main abutment surfaces 26a, 26b and the sub-abutment surfaces 26c, 26d abut against each other, so that the distance between the meshing portion 24 and the opposing portion 25 is regulated so that they do not approach each other more than a certain amount. In addition, since they abut at three points, the angle of the opposing portion 25 relative to the meshing portion 24 is stable. As a result, the relative angle between the main teeth 24a and the opposing teeth 25a can be kept constant, so that the feed screw 51 can stably maintain the distance between the opposing teeth 25a in the normal usage state. In this embodiment, two of the three abutment surfaces, the main abutment surfaces 26a, 26b and the sub abutment surfaces 26c, 26d, are provided on the same line in the axial direction of the feed screw 51, but the present invention is not limited thereto. In this embodiment, the sub abutment surfaces are set smaller than the main abutment surfaces, but the main abutment surfaces may be set smaller. In this embodiment, the main abutment surface 26b is not on the same plane as the main abutment surface 26a when viewed from a direction perpendicular to the axis, but they may be provided on the same plane.

[0029] As shown in Figs. 2 and 3(b), the arm 42 of the sandwich spring 40 includes a parallel portion configured parallel to the axial direction of the feed screw 51. The parallel portion is set to bias the facing portion 25 toward the meshing portion 24 between a straight line LL that passes through the center of the sub-abutment surface 26c and is parallel to the axial direction, and the center of the sub-abutment surface 26d, in a direction perpendicular to the axial direction of the feed screw 51 and parallel to the sub-abutment surfaces 26c and 26d. In the axial direction, the sandwich spring 40 is set to press and bias between the two sub-abutment surfaces 26c. Specifically, it is preferable to bias the periphery of a point that is the middle of the two straight lines in the direction perpendicular to the axial direction and the middle of the two sub-abutment surfaces 26c in the axial direction. Alternatively, by biasing between the abutment surfaces, a force is applied evenly to each abutment surface, so that the relative position of the facing portion 25 with respect to the meshing portion 24 can be stably maintained even if an impact is applied to the device. Although not shown in this embodiment, an abutment surface may be provided to prevent deviation of the relative positions of the meshing portion 24 and the opposing portion 25 in a direction parallel to the main teeth 24a (the direction of the arrow X in FIG. 3).

[0030] Fig. 6 is an enlarged plan view of the engagement portion between the feed screw 51 and the rack 20. Fig. 6(a) shows a normal state in which no opening action, which will be described later, occurs, and Fig. 6(b) shows a state in which an opening action occurs. Fig. 7 is an enlarged cross-sectional view showing the engagement between the main tooth 24a, the counter tooth 25a, and the feed screw 51, and corresponds to a view seen from the direction of the arrow X shown in Fig. 6(b).

[0031] First, consider a plane passing through the center axis of the feed screw 51 and the contact position between the main tooth 24a and the feed screw 51 in the normal state. The normal state is a state in which the main tooth 24a is engaged with the feed screw 51 by the biasing force of the torsion coil spring 30, and no impact is applied to the lens driving mechanism, that is, no acceleration is applied between the feed screw 51 and the rack 20. In the normal state, the main contact surfaces 26a, 26b and the sub contact surfaces 26c, 26d contact each other, and the distance between the closest parts of the main tooth 24a and the opposing tooth 25a is smaller than the outer diameter D of the feed screw 51. In the normal state, the main contact surfaces 26a, 26b and the sub contact surfaces 26c, 26d contact each other, and the opposing tooth 25a and the feed screw 51 do not contact each other, and there is play. FIG. 7 is an enlarged cross-sectional view showing cases where various types of impacts are applied to the feed screw 51 with respect to the main tooth 24a and the counter tooth 25a.

[0032] 7(a) shows a state in which an impact value A is applied in the axial direction to the feed screw 51. At this time, the main teeth 24a engage with the threads of the feed screw 51, so that the rack 20 does not shift in the axial direction of the feed screw 51. Figure 7(b) shows a state where an impact value B larger than the impact value A is applied axially to the feed screw 51, and the main tooth 24a has risen along the thread of the feed screw 51. At this time, since the meshing portion 24 and the opposing portion 25 are biased by the clamping spring 40, the interval d defined by the interval between the peaks (the closest positions) of the threads of the main tooth 24a and the opposing tooth 25a is maintained, so the opposing portion 25 approaches the thread of the feed screw 51. The interval d between the main tooth 24a and the opposing tooth 25a is set to be smaller than the outer diameter D of the feed screw 51. Therefore, both the main tooth 24a and the opposing tooth 25a engage with the thread of the feed screw 51, and the rack 20 does not move further in the axial direction of the feed screw 51 beyond the thread of the feed screw 51.

[0033] Figures 6(b) and 7(c) show a state where an impact value C larger than the impact value B is applied axially to the feed screw 51. Due to the resistance force from the thread of the feed screw 51, forces in the direction of moving away from each other are applied to the main tooth 24a and the opposing tooth 25a. When this force exceeds the biasing force obtained by subtracting the reaction force generated at the connecting portion 27 from the biasing force of the clamping spring 40, an opening operation of the meshing portion 24 and the opposing portion 25 occurs against the elastic force of the clamping spring 40. As a result, the interval between the main tooth 24a and the opposing tooth 25a widens to d'. Here, the magnitude relationship among D, d, and d' is d < D ≤ d'. Therefore, a tooth jump that allows the rack teeth to move axially over the thread of the feed screw 51 is permitted. Thereby, it is possible to prevent large shear forces from being applied to the tooth tips of the main tooth 24a and the opposing tooth 25a, resulting in damage such as chipping or abrasion of the rack teeth or the feed screw. If these chippings or abrasions occur, the operation becomes unstable in subsequent product operations, causing operational failures. In this embodiment, by adjusting the biasing force of the clamping spring 40, it is possible to arbitrarily set the impact value C at which the opening operation of the rack 20 begins to occur.

[0034] The rack of this embodiment and the drive mechanism using it can also be applied to a lens group having a mechanism for moving in the optical axis direction, such as the zoom drive means 107. In this embodiment, the optical device having the rack 20 is an imaging device such as a lens-integrated digital still camera, but it may also be a lens device that is detachably attached to the imaging device.

[0035] In the embodiment, the facing portion 25 of the rack 20 is connected to the mounting portion 21 by the connecting portion 27, and the meshing portion 24, the facing portion 25, the connecting portion 27, and the mounting portion 21 are configured as an integrated element, but the present invention is not limited to this. The facing portion 25 may be configured as a separate element without being connected by the connecting portion 27. In that case, a configuration for stabilizing the position of the facing portion 25 relative to the meshing portion 24 may be added. However, even with this configuration, it is possible to enjoy the effect of the present invention, that is, to reduce the driving load and suppress damage such as chipping and scraping of the feed screw 51, the main teeth 24a, and the facing teeth 25a even when an impact force is applied, without departing from the spirit of the present invention.

[0036] An imaging device that enjoys the effects of the present invention can be provided by an imaging device having a lens device with the lens drive mechanism of the present invention and an imaging element that receives an image formed by the lens device. Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the present invention.

[0037] The disclosure of this embodiment includes the following configuration. (Configuration 1) a holding member that holds the lens and is movable in the optical axis direction; a feed screw extending in the optical axis direction; A drive means for rotating the feed screw; a rack including: an engagement portion having a first portion that engages with the feed screw; an opposing portion having a second portion that is disposed opposite the first portion across the feed screw; and an attachment portion that is connected to the holding member so as to be immovable in the optical axis direction; a first elastic member that biases the meshing portion against the feed screw with a first force; a second elastic member that biases the first contact portion of the meshing portion and the second contact portion of the opposing portion so as to press them against each other with a second force. (Configuration 2) The lens driving mechanism described in configuration 1, characterized in that when the first abutment portion and the second abutment portion are in abutment with each other, the distance between the closest portions of the first portion and the second portion is smaller than the outer diameter of the feed screw. (Configuration 3) The lens driving mechanism according to configuration 1 or 2, characterized in that when the first contact portion and the second contact portion are in contact with each other, the second portion has play between itself and the feed screw. (Configuration 4) The lens driving mechanism according to any one of configurations 1 to 3, wherein the first force is smaller than the second force. (Configuration 5) The rack has an elastic connecting portion that connects the mounting portion and the opposing portion, The lens driving mechanism described in any one of configurations 1 to 4, characterized in that when a force required to elastically deform the connection portion to bring the first contact portion and the second contact portion into contact with each other in a state in which the second force is not applied is defined as a third force, when the first contact portion and the second contact portion are in contact with each other by the second elastic member, the first force is smaller than a force obtained by subtracting the third force from the second force. (Configuration 6) A convex portion is provided on one of the meshing portion and the opposing portion, a recess that engages with the protrusion in the other of the meshing portion and the opposing portion when the first contact portion and the second contact portion are in contact with each other, The lens driving mechanism described in any one of configurations 1 to 5, characterized in that when the first abutment portion and the second abutment portion abut against each other, the convex portion and the concave portion engage with each other to suppress relative movement between the meshing portion and the opposing portion in the axial direction of the feed screw. (Configuration 7) 7. The lens drive mechanism according to any one of configurations 1 to 6, wherein the first portion has first gear teeth that mesh with the lead screw. (Configuration 8) The lens drive mechanism according to any one of configurations 1 to 7, wherein the second portion has second gear teeth that mesh with the lead screw. (Configuration 9) The lens driving mechanism according to any one of configurations 1 to 7, wherein the second portion has a surface parallel to an axial direction of the feed screw. (Configuration 10) The first abutment portion is composed of three abutment surfaces, and includes two abutment surfaces arranged at a distance in the axial direction of the feed screw, and one abutment surface arranged at a distance in a direction perpendicular to the axial direction and parallel to the two abutment surfaces, The lens driving mechanism according to any one of configurations 1 to 9, characterized in that the second abutment portion is composed of three abutment surfaces that abut against the two abutment surfaces and the one abutment surface included in the first abutment portion. (Configuration 11) the first abutment portion is composed of three abutment surfaces, and includes two eleventh abutment surfaces spaced apart from each other in the axial direction of the feed screw, and a twelfth abutment surface spaced apart from the two eleventh abutment surfaces in a direction perpendicular to the axial direction, parallel to the two eleventh abutment surfaces, and perpendicular to the two eleventh abutment surfaces; A lens driving mechanism described in any of configurations 1 to 9, characterized in that the second abutment portion is composed of two 21st abutment surfaces abutting the two 11th abutment surfaces, and a 22nd abutment surface abutting the 12th abutment surface. (Configuration 12) The lens driving mechanism described in any one of configurations 1 to 11, characterized in that the second elastic member has an arm portion that urges the opposing portion toward the meshing portion between a straight line passing through the centers of the two 21st abutment surfaces and the center of one of the 21st abutment surfaces in a direction perpendicular to the axial direction of the feed screw and parallel to the two 21st abutment surfaces. (Configuration 13) The lens driving mechanism described in configuration 5, characterized in that the connection portion connects the mounting portion and the opposing portion so as to surround 25% or more of the outer periphery of the mounting portion, centered on the axial direction of the feed screw. (Configuration 14) 14. A lens device having a lens driving mechanism according to any one of configurations 1 to 13. (Configuration 15) 15. An imaging device comprising the lens device according to configuration 14 and an imaging element that receives an image formed by the lens device. [Explanation of symbols]

[0038] 10: Holding member 20: Rack 21: Mounting part 24: Meshing part 25: Opposing part 24a: Real tooth (first part) 25a: opposing tooth (second part) 30: Torsion coil spring (first elastic member) 40: sandwiching spring (second elastic member) 50: Focus motor (driving means) 51: Lead screw

Claims

1. a holding member that holds the lens and is movable in the optical axis direction; a feed screw extending in the optical axis direction; A drive means for rotating the feed screw; a rack including: a meshing portion having a first portion that meshes with the feed screw; an opposing portion having a second portion that is disposed opposite the first portion across the feed screw; and an attachment portion that is connected to the holding member; a first elastic member that biases the meshing portion against the feed screw with a first force; a second elastic member that biases the first contact portion of the meshing portion and the second contact portion of the opposing portion so as to press them against each other with a second force.

2. 2. The lens driving mechanism according to claim 1, wherein when the first contact portion and the second contact portion are in contact with each other, the distance between the closest portions of the first portion and the second portion is smaller than the outer diameter of the feed screw.

3. 3. The lens driving mechanism according to claim 1, wherein the second portion has a play between the second portion and the feed screw when the first contact portion and the second contact portion are in contact with each other.

4. 2. The lens driving mechanism according to claim 1, wherein the first force is smaller than the second force.

5. The rack has an elastic connecting portion that connects the mounting portion and the opposing portion, The lens driving mechanism described in claim 1, characterized in that when a force required to elastically deform the connection portion to bring the first abutment portion and the second abutment portion into contact with each other when the second force is not applied is defined as a third force, when the first abutment portion and the second abutment portion are in contact with each other by the second elastic member, the first force is smaller than a force obtained by subtracting the third force from the second force.

6. A convex portion is provided on one of the meshing portion and the opposing portion, a recess that engages with the protrusion in the other of the meshing portion and the opposing portion when the first contact portion and the second contact portion are in contact with each other, The lens driving mechanism according to claim 1, characterized in that when the first abutment portion and the second abutment portion abut against each other, the convex portion and the concave portion engage with each other to suppress relative movement between the meshing portion and the opposing portion in the axial direction of the feed screw.

7. 2. The lens drive mechanism according to claim 1, wherein the first portion has first gear teeth that mesh with the lead screw.

8. 2. The lens drive mechanism according to claim 1, wherein the second portion has second gear teeth that mesh with the lead screw.

9. 2. The lens driving mechanism according to claim 1, wherein the second portion has a surface parallel to an axial direction of the feed screw.

10. The first abutment portion is composed of three abutment surfaces, and includes two abutment surfaces arranged at a distance in the axial direction of the feed screw, and one abutment surface provided at a distance in a direction perpendicular to the axial direction and parallel to the two abutment surfaces, 2 . The lens driving mechanism according to claim 1 , wherein the second contact portion is composed of three contact surfaces which contact the two contact surfaces and the one contact surface included in the first contact portion, respectively.

11. The first abutment portion is composed of three abutment surfaces, and includes two eleventh abutment surfaces spaced apart in the axial direction of the feed screw, and a twelfth abutment surface spaced apart from the two eleventh abutment surfaces in a direction perpendicular to the axial direction, parallel to the two eleventh abutment surfaces, and perpendicular to the two eleventh abutment surfaces, 2. The lens driving mechanism according to claim 1, wherein the second contact portion is composed of two 21st contact surfaces that contact the two 11th contact surfaces, and a 22nd contact surface that contacts the 12th contact surface.

12. The lens driving mechanism described in claim 1, characterized in that the second elastic member has an arm portion that urges the opposing portion toward the meshing portion between a straight line passing through the centers of the two 21 abutment surfaces and the center of one of the 21 abutment surfaces in a direction perpendicular to the axial direction of the feed screw and parallel to the two 21 abutment surfaces.

13. 6. The lens driving mechanism according to claim 5, wherein the connection portion connects the mounting portion and the opposing portion so as to surround at least 25% of the outer periphery of the mounting portion, centered on the axial direction of the feed screw.

14. A lens device comprising the lens driving mechanism according to claim 1.

15. 15. An imaging device comprising: a lens apparatus according to claim 14; and an imaging element that receives an image formed by the lens apparatus.

Images