JP6091973B2 - Drive device for linear moving body - Google Patents

Description

  The present invention relates to a drive device that linearly moves a rectilinear moving body, and more particularly to a mechanism that suppresses vibrations when driving the rectilinear moving body.

  For example, instead of a feed screw mechanism that converts rotational motion into linear motion, the focusing lens group (straight forward moving body) of the photographic lens is provided with a drive device that linearly drives with a voice coil motor (linear drive mechanism) using permanent magnets and coils. There are known cameras. In this type of driving device, in order to suppress unnecessary resonance with respect to the oscillation of the voice coil motor, a countermeasure has been taken in which grease is applied to the rectilinear guide portion that linearly guides the rectilinear moving body (Patent Document 1). However, it has been difficult to obtain stable performance because it is difficult to make the applied amount of grease uniform, the temperature dependence of the viscosity of the grease is large, and the effect of the grease tends to decrease due to aging. In addition, there is a problem that the grease easily leaks and adheres to other parts.

JP 2011-203385 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a drive device for a rectilinear moving body that can reliably suppress vibration during driving with a simple configuration.

The linear moving body drive device according to the present invention includes: a support member; a linear movement body supported so as to be linearly movable with respect to the support member; linear drive means for applying a driving force in the linear movement direction to the linear movement body; A cylinder part having a hollow portion formed in one of the linearly moving bodies and formed in the direction of linear movement of the linearly moving body; inserted into the cylinder part slidably provided in the other of the support member and the linearly moving body. A piston portion that suppresses vibration when the linearly moving body is driven by a linear drive mechanism by air resistance when the piston portion moves in the cylinder portion , and has the following configuration. It is said.

  As a first form, a support member is constituted by at least one guide shaft extending in the moving direction of the rectilinear moving body and a holder for supporting and fixing the guide shaft, and the inside is hollow and the guide shaft is inserted. The outer cylindrical portion to be formed is formed in the holder, and the inner cylindrical portion that is slidably inserted between the outer peripheral surface of the guide shaft and the inner peripheral surface of the outer cylindrical portion is formed in the rectilinear moving body. It is possible to use the cylindrical portion as the cylinder portion and the inner cylindrical portion of the rectilinear moving body as the piston portion.

  In this form, the small cylindrical portion that does not contact the inner peripheral surface of the outer cylindrical portion, and the sliding that slidably contacts the inner peripheral surface of the outer cylindrical portion on the inner cylindrical portion of the rectilinear moving body It is preferable to provide an annular portion and to form a communicating portion that allows air to flow inside and outside the outer cylindrical portion in the sliding annular portion.

  As a second embodiment, at least one guide shaft extending in the moving direction of the rectilinear moving body is provided as a support member, and a hollow portion through which the guide shaft is inserted is formed inside, with respect to the outer peripheral surface of the guide shaft. A cylindrical portion that is slidably supported is provided on the rectilinear moving body, and a sliding annular portion that is slidably in contact with the inner peripheral surface of the cylindrical portion is provided on the outer peripheral surface of the guide shaft. It is possible to use the cylindrical portion as the cylinder portion and the sliding annular portion on the guide shaft as the piston portion.

  In this form, it is preferable that the cylindrical part of the rectilinear moving body has a lid part that can be attached to the end part. The lid portion allows the sliding annular portion to be inserted into the hollow portion in the non-attached state, and restricts the detachment of the sliding annular portion from the hollow portion in the attached state. Thereby, the assembling property of the rectilinearly moving body with respect to the guide shaft can be improved.

  The present invention is suitable for a drive device that uses, as linear drive means, a voice coil motor that generates thrust to a rectilinearly moving body by energizing a coil disposed in the magnetic field of the magnetic body.

  The present invention can be applied to driving devices for linearly moving bodies in various fields, and is particularly suitable for driving devices for optical elements in optical instruments such as lens barrels. More specifically, the optical element holding frame that holds the optical element may be used in a driving device that moves straight in the optical axis direction of the imaging optical system.

According to the present invention, the cylinder portion provided in the mechanism that supports the linear moving mechanism so that the linearly moving body is driven so as to be linearly movable (the guide shaft is inserted into the support member). The outer cylindrical part or the cylindrical part provided on the rectilinear moving body and supported slidably with respect to the outer peripheral surface of the guide shaft) and the piston part (between the outer cylindrical part provided on the rectilinear moving body and the guide shaft) The inner cylindrical portion slidably inserted into the guide shaft or the sliding annular portion provided on the outer peripheral surface of the guide shaft and slidably in contact with the inner peripheral surface of the cylindrical portion) is suppressed by using air resistance. Therefore, reliable vibration suppression can be realized with a simple configuration.

1 is a front exploded perspective view showing a first embodiment in which a driving device for a linearly moving body according to the present invention is applied to a driving device for a focusing lens group of a lens barrel. FIG. 2 is a front exploded perspective view showing a partially assembled state of the lens barrel in FIG. 1. It is the back disassembled perspective view which looked at FIG. 1 from the different direction. It is the back disassembled perspective view which looked at FIG. 2 from the different direction. It is a front perspective view which shows the state which combined the fixed board | substrate and the linear drive mechanism in 1st Embodiment. It is a front perspective view of the linear drive mechanism and movable lens frame of 1st Embodiment. It is a front perspective view of a linear drive mechanism and a movable lens frame in a state where the holder of the first embodiment is removed. It is the figure which looked at the linear drive mechanism and movable lens frame of the state which removed the holder of 1st Embodiment from the to-be-photographed object side. It is sectional drawing of the support mechanism of a movable lens frame in the state where a movable lens frame is located in the image plane side in a 1st embodiment. It is sectional drawing of the support mechanism of a movable lens frame in the state where a movable lens frame is located in the to-be-photographed object side in 1st Embodiment. FIG. 5 is a front exploded perspective view showing a second embodiment in which the driving device for a linearly moving body according to the present invention is applied to a driving device for a focusing lens group of a lens barrel. FIG. 12 is a front exploded perspective view showing an intermediate assembly state of the lens barrel of FIG. 11. It is the back disassembled perspective view which looked at FIG. 11 from the different direction. It is the back disassembled perspective view which looked at FIG. 12 from the different direction. It is a front perspective view which shows the state which combined the fixed board | substrate and the linear drive mechanism in 2nd Embodiment. It is a front perspective view of the linear drive mechanism and movable lens frame of 2nd Embodiment. It is sectional drawing of the support mechanism of a movable lens frame in the state in which a movable lens frame is located in the image plane side in 2nd Embodiment. It is sectional drawing of the support mechanism of a movable lens frame in the state where a movable lens frame is located in the to-be-photographed object side in 2nd Embodiment.

  FIGS. 1 to 10 show a first embodiment in which the driving device for a linearly moving body according to the present invention is applied to a driving device for a focusing lens group (optical element) L1 of a lens barrel. The illustrated embodiment is intended to depict only the driving device for the focusing lens group L1, and the configuration of the other portions is omitted.

  The lens barrel has, as a fixing member, a fixed substrate 32 on which an image sensor 31 for forming a subject image formed by a photographing lens system including the focusing lens group L1 is fixed, and a stationary ring that supports the photographing lens system inside. 33. In the direction of the optical axis O of the photographic lens system, the subject side is the front and the imaging plane side is the rear. The fixed substrate 32 is assembled to the rear end portion of the fixed ring 33. Two guide shafts (support members) 34, 35 parallel to the optical axis O are fixed to the fixed substrate 32, and the front ends of the guide shafts 34, 35 are holders (support members) described later. ) 21 (FIGS. 9 and 10). Each of the guide shafts 34 and 35 has a uniform circular cross-sectional shape in the longitudinal direction.

  The movable lens frame (straightly moving body, optical element holding frame) 10 includes a cylindrical frame portion 10a that holds the focusing lens group L1, and a radial arm portion 10b that extends from the cylindrical frame portion 10a in the outer radial direction. A cylindrical portion (piston portion, inner cylindrical portion, small-diameter cylindrical portion) 10c that is slidably fitted to the guide shaft 34 and a guide shaft 35 is slidably engaged with the distal end portion of the radial arm portion 10b. A bifurcated portion 10d is formed. As shown in FIGS. 9 and 10, a hollow portion 10e penetrating in the direction of the optical axis O is formed inside the cylindrical portion 10c, and a guide shaft 34 is inserted into the hollow portion 10e. The inner peripheral surface of the cylindrical portion 10c facing the hollow portion 10e has a cylindrical shape concentric with the guide shaft 34, and there is a predetermined clearance between the inner peripheral surface of the cylindrical portion 10c and the guide shaft 34 (each other Non-contact). Support ring portions 10f and 10g having a smaller opening diameter than the hollow portion 10e are formed inside the front and rear end portions of the cylindrical portion 10c, and the inner peripheral surfaces of the support ring portions 10f and 10g are with respect to the outer peripheral surface of the guide shaft 34. And slidably touch. Moreover, the coil 11 which comprises a linear drive mechanism is fixed to the front-end | tip part of the radial direction arm part 10b so that it may be located between the cylindrical part 10c and the forked part 10d. This coil 11 is a flat air-core coil whose winding center is in a direction parallel to the optical axis O. The movable lens frame 10 is formed with a horizontally long through hole 10h (FIGS. 1, 3, 9, and 10) corresponding to the shape of the air core of the coil 11.

  A magnet unit 20 that constitutes a linear drive mechanism together with the coil 11 is fixed to the fixed ring 33 and the fixed substrate 32. The magnet unit 20 has a configuration in which a pair of yokes 22 and 23 and a permanent magnet 24 are supported on a holder 21 fixed to a fixed substrate 32 and a fixed ring 33, and the illustration of the holder 21 is omitted in FIGS. 7 and 8. doing. Each of the yoke 22 and the yoke 23 has longitudinal walls 22a and 23a that are long in the optical axis O direction, and short-side walls 22b and 23b that are substantially orthogonal to the longitudinal walls 22a and 23a. 22a and the longitudinal wall 23a are opposed to each other, and the short-side wall 22b and the short-side wall 23b are opposed to each other so as to draw a closed section by the yoke 22 and the yoke 23. The permanent magnet 24 has an elongated shape fixed on the longitudinal wall 23 a of the yoke 23. The longitudinal wall 22 a of the yoke 22 is inserted into the horizontally long through hole 10 h of the movable lens frame 10 and the air core portion of the coil 11 without contact. The longitudinal wall 22a of the yoke 22 in the magnetic field of the permanent magnet 24 and the coil 11 constitute a voice coil motor. When the coil 11 is energized in the forward and reverse directions, the movable lens frame 10 (focusing lens group) together with the coil 11 is provided. L1) moves along the guide shafts 34 and 35 in the direction of the optical axis O.

  The lens barrel includes vibration suppression means that suppresses resonance of the movable lens frame 10 due to oscillation of a linear drive mechanism when driving the movable lens frame 10. In the first embodiment, vibration suppression means is provided between the holder 21 and the movable lens frame 10.

  The holder 21 has a frame shape having a pair of side portions 21a and 21b extending in the direction of the optical axis O and a bridging portion 21c connecting the front end portions of the pair of side portions 21a and 21b. As shown in FIG. 10, guide shafts 34 and 35 are disposed between the side portions 21a and 21b, and the front ends of the guide shafts 34 and 35 are inserted and fixed in support holes formed in the bridging portion 21c. The The yokes 22 and 23 and the permanent magnet 24 are inserted and held in the space between the side portions 21a and 21b (FIGS. 2, 4, 5, and 6). The holder 21 is further formed with a cylindrical guide portion (cylinder portion, outer cylindrical portion) 21d along the side portion 21a. As shown in FIGS. 9 and 10, the cylindrical guide portion 21d has a hollow portion 21e therein. The front end portion of the hollow portion 21e is closed by the bridging portion 21c, the rear end portion of the hollow portion 21e is opened, and the guide shaft 34 is inserted into the hollow portion 21e. The inner peripheral surface of the cylindrical guide portion 21d facing the hollow portion 21e has a cylindrical shape concentric with the guide shaft 34, and there is a predetermined clearance between the inner peripheral surface of the hollow portion 21e and the guide shaft 34 ( Are not in contact with each other).

  9 and 10, the cylindrical portion 10c of the movable lens frame 10 is inserted into the hollow portion 21e of the holder 21 (between the outer peripheral surface of the guide shaft 34 and the inner peripheral surface of the cylindrical guide portion 21d). The Near the front end of the tubular portion 10c of the movable lens frame 10, a sliding annular portion (piston portion, inner tubular portion) 10i having a slightly larger outer diameter than other portions of the tubular portion 10c is formed. Yes. As shown in FIG.7 and FIG.8, the flow notch (communication part) 10j is formed by notching a part of sliding annular part 10i. FIG. 9 shows a state in which the movable lens frame 10 is at the rear (imaging plane side) moving end in the optical axis O direction, and FIG. 10 shows the movable lens frame 10 at the front (subject side) moving end in the optical axis O direction. Shows the state. The sliding annular portion 10 i is located in the hollow portion 21 e of the holder 21 over the entire movable range of the movable lens frame 10. The sliding annular portion 10i is set to have an outer diameter size that fits without looseness on the inner peripheral surface of the hollow portion 21e, and the hollow portion 21e is closed by the cylindrical portion 10c including the sliding annular portion 10i and the guide shaft 34. Thus, the flow of air inside and outside the hollow portion 21e is allowed through the flow cutout 10j. Since the opening area of the flow notch 10j is very small compared to the cross-sectional area of the hollow portion 21e, an air damper effect due to air resistance is obtained when the movable lens frame 10 moves forward and backward in the direction of the optical axis O, and the movable lens frame 10 Vibration is suppressed. Thereby, the resonance of the movable lens frame 10 caused by oscillation in the voice coil motor constituting the linear drive mechanism can be prevented. The effect of the air damper can be adjusted by the size, shape, number, etc. of the distribution notches 10j.

  FIGS. 11 to 17 show a second embodiment in which the driving device for the linearly moving body according to the present invention is applied to the driving device for the focusing lens group (optical element) L1 of the lens barrel. Portions common to the first embodiment are denoted by common reference numerals in the drawing and description thereof is omitted.

  In the second embodiment, vibration suppressing means is provided between the movable lens frame 10 and the guide shaft 34. A cylindrical portion (cylinder portion) 10k that is slidably fitted to the guide shaft 34 by the movable lens frame 10 has a front end portion including a support ring portion 10f as a separate holding lid portion (cylinder portion) 10m. The hollow portion 10e in the cylindrical portion 10k is opened forward with the holding lid portion 10m removed. A small-diameter ring portion 10n (FIGS. 11, 17, and 18) is formed at the front end of the cylindrical portion 10k, and the holding lid portion 10m is fitted to the small-diameter ring portion 10n as shown in FIGS. Combined.

  A packing (piston portion, sliding annular portion) 40 that is an annular body having a larger diameter than the guide shaft 34 is supported at an intermediate position in the axial direction of the guide shaft 34. The outer diameter size of the packing 40 is larger than the inner diameter size of the support ring portion 10f in the holding lid portion 10m, and the hollow portion from the front in the state where the holding lid portion 10m is removed from the cylindrical portion 10k as shown in FIGS. The guide shaft 34 including the packing 40 can be inserted into 10e. FIG. 17 shows a state in which the movable lens frame 10 is located at the rear (imaging plane side) moving end in the optical axis O direction, and FIG. 18 shows a state where the movable lens frame 10 is located at the front (subject side) moving end in the optical axis O direction. Shows the state. The packing 40 is located in the hollow portion 10e over the entire movable range of the movable lens frame 10. When the holding lid portion 10m is attached with the guide shaft 34 inserted into the cylindrical portion 10k, the air flow between the outside of the hollow portion 10e between the packing 40 and the support ring portion 10f is restricted, and the movable lens frame An air damper effect due to air resistance is obtained when 10 moves forward and backward in the direction of the optical axis O, and vibration (resonance) of the movable lens frame 10 is suppressed. The effect of the air damper can be adjusted by the clearance between the inner peripheral surface of the cylindrical portion 10k and the packing 40. Moreover, since the air damper effect is also affected by the hardness of the packing 40, the hardness of the packing 40 may be changed according to the intended effect. Basically, as the packing 40 becomes larger in diameter and becomes softer, the amount of air fluctuation in the hollow portion 10e due to deformation of the packing 40 and the variation in the clearance between the inner peripheral surface of the cylindrical portion 10k and the packing 40 increase. Since it is difficult to control the air damper effect, it is preferable that the packing 40 has a certain degree of rigidity.

  In each of the above embodiments, a cylinder portion and a piston portion are provided in a support mechanism that movably supports the movable lens frame 10 in the direction of the optical axis O, and air resistance when the piston portion slides relative to the cylinder portion is an air damper. As a result, vibration when the movable lens frame 10 is driven is suppressed by a linear drive mechanism including a voice coil motor. Specifically, in the first embodiment, the cylindrical guide portion 21d provided on the holder 21 that supports the front end portions of the guide shafts 34 and 35 is used as a cylinder portion, and the movable lens frame 10 that receives the guide shaft 34 is used. The cylindrical portion 10c (sliding annular portion 10i) is a piston portion. In the second embodiment, the cylindrical portion 10k and the holding lid portion 10m of the movable lens frame 10 are used as cylinder portions, and the packing 40 provided on the guide shaft 34 is used as a piston portion. According to the configuration of each of these embodiments, a change in performance due to secular change and temperature change is small, and a clean and stable damper effect is achieved, compared to a configuration in which vibration is suppressed by using viscous resistance by grease or other friction members. Can be obtained. Further, by utilizing a part of the support mechanism of the movable lens frame 10 as vibration suppressing means, a configuration that saves space and reduces the number of components is realized.

  The damper effect for the movable lens frame 10 is set so that unnecessary vibration (resonance) of the movable lens frame 10 can be reliably suppressed, and the loss of driving force is small and the power consumption of the linear drive mechanism can be suppressed. It is preferable. As described above, in the first embodiment, the damper effect can be adjusted by the size, shape, number, etc. of the flow notches 10j. In the second embodiment, the inner peripheral surface of the cylindrical portion 10k and the packing 40 can be adjusted. The damper effect can be adjusted according to the clearance between and the hardness of the packing 40. In addition to this, the damper effect is adjusted by the size of the clearance between the outer peripheral surface of the sliding annular portion 10i and the inner peripheral surface of the cylindrical guide portion 21d without providing the flow notch 10j in the first embodiment. Alternatively, the damper effect can be adjusted by forming a portion corresponding to the flow notch 10j in the packing 40 in the second embodiment. Furthermore, a groove for air circulation is formed on the inner peripheral surface of the cylindrical guide portion 21d in the first embodiment and the inner peripheral surface of the cylindrical portion 10k in the second embodiment to adjust the damper effect. It is also possible. As described above, according to the configuration in which a part of the support mechanism of the movable lens frame 10 is utilized as the vibration suppressing means, a high degree of freedom can be obtained regarding the adjustment of the damper effect.

  As mentioned above, although demonstrated based on illustration embodiment, this invention is not limited to illustration embodiment. For example, the present invention is suitable for a driving device for a focusing lens group as in the embodiment, but can also be applied as a driving device for a rectilinearly moving body other than the focusing lens group. In the field of optical equipment, the present invention can also be applied to a zoom lens group driving device for zooming.

L1 Focusing lens group (optical element)
O Optical axis 10 Movable lens frame (straightly moving body, optical element holding frame)
10c cylindrical part (piston part, inner cylindrical part, small diameter cylindrical part)
10e hollow part 10f 10g support ring part 10i sliding annular part (piston part, inner cylindrical part)
10j Distribution cutout (communication part)
10k cylindrical part (cylinder part)
10m Holding lid (cylinder part)
10n small diameter ring 11 coil (linear drive mechanism)
20 Magnet unit (linear drive mechanism)
21 Holder (support member)
21d Cylindrical guide part (cylinder part, outer cylindrical part)
21e Hollow portion 22 23 Yoke 24 Permanent magnet 32 Fixed substrate 33 Fixed ring 34 35 Guide shaft (support member)
40 Packing (sliding annular part)

Claims (6)

A support member;
A rectilinear moving body supported so as to be capable of rectilinear movement with respect to the support member;
A linear drive mechanism that applies a driving force in the linearly moving direction to the linearly moving body;
A cylinder portion having a hollow portion formed in one of the support member and the rectilinear moving body and formed in a direction of rectilinear movement of the rectilinear moving body; and provided in the other of the support member and the rectilinear moving body, A piston part slidably inserted into the cylinder part;
Have
The support member has at least one guide shaft extending in the moving direction of the rectilinear moving body, and a holder for supporting and fixing the guide shaft,
As the cylinder portion, an outer cylindrical portion having a hollow inside is formed in the holder, and the guide shaft is inserted into the outer cylindrical portion,
As the piston portion, an inner cylindrical portion that is slidably inserted between the outer peripheral surface of the guide shaft and the inner peripheral surface of the outer cylindrical portion is formed in the rectilinearly moving body,
The vibration when driving the linear moving object by the linear drive mechanism, suppression by the air resistance when the inner cylindrical portion constituting the piston portion the outer cylindrical portion constituting the cylinder portion moves A drive device for a rectilinearly moving body. 2. The linear moving body drive device according to claim 1, wherein the inner cylindrical portion is a small-diameter cylindrical portion that does not contact the inner peripheral surface of the outer cylindrical portion, and an inner peripheral surface of the outer cylindrical portion. Drive device for a rectilinear moving body having a large-diameter sliding annular portion that is slidably in contact with the sliding annular portion and a communication portion that allows air to flow inside and outside the outer cylindrical portion . A support member;
A rectilinear moving body supported so as to be capable of rectilinear movement with respect to the support member;
A linear drive mechanism that applies a driving force in the linearly moving direction to the linearly moving body;
A cylinder portion having a hollow portion formed in one of the support member and the rectilinear moving body and formed in the rectilinear movement direction of the rectilinear moving body; and
A piston portion slidably inserted into the cylinder portion, provided on the other of the support member and the rectilinearly moving body;
Have
The support member has at least one guide shaft extending in the moving direction of the rectilinear moving body,
As the cylinder part, a hollow part through which the guide shaft is inserted is formed in the rectilinearly moving body, and a cylindrical part that is slidably supported with respect to the outer peripheral surface of the guide shaft is provided.
The piston portion has a sliding annular portion provided on the outer peripheral surface of the guide shaft and slidably in contact with the inner peripheral surface of the cylindrical portion,
Vibration when driving the linearly moving body by the linear drive mechanism is suppressed by air resistance when the sliding annular part constituting the piston part moves in the cylindrical part constituting the cylinder part. A drive device for a rectilinearly moving body. 4. The linear moving body drive device according to claim 3, wherein the cylindrical portion is attachable to an end portion, allows insertion of the sliding annular portion into the hollow portion in a non-attached state, and allows the hollow portion in the attached state. A drive device for a rectilinear moving body having a lid portion for restricting the detachment of the sliding annular portion from the portion . 5. The linear moving body drive device according to claim 1, wherein the linear drive mechanism includes a magnetic body including a permanent magnet and a coil provided in a magnetic field of the magnetic body. A driving device for a rectilinear moving body, which is a voice coil motor that generates a thrust to the rectilinear moving body by energizing the motor . 6. The linear moving body drive device according to claim 1, wherein the linear moving body holds an optical element constituting the photographing optical system and can move straight in the optical axis direction of the photographing optical system. Drive device for a rectilinearly moving body, which is an optical element holding frame supported by the head .

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