JP2021067862A - Drive mechanism, lens barrel, and imaging unit - Google Patents

Abstract

To provide a drive mechanism capable of driving an optical element with a cam member without increasing the size of the device.SOLUTION: The drive mechanism includes a cam member (90) and a cam (901) that is placed on the cam member and is engaged with an optical element (1) that is movable in the optical axis direction by the cam member. The cam has a first plane (901a) and a second plane (901b). When the first plane acts as a cam plane, the second plane functions as a cam follower urging plane; and when the second plane acts as a cam plane, the first plane functions as a cam follower urging plane.SELECTED DRAWING: Figure 1

Description

The present invention relates to a drive mechanism for moving an optical element with respect to the optical axis direction by a cam member during a variable magnification operation, and moves a plurality of optical elements using a cam member that rotates mainly with an axis parallel to the optical axis as a rotation axis. Regarding the drive mechanism.

Conventionally, in a lens barrel equipped with a drive mechanism for moving a plurality of optical elements using a tubular cam member that rotates with an axis parallel to the optical axis as a rotation axis, in order to suppress the driving force for moving the optical elements. In general, the cam diameter was increased for the purpose of laying down (reducing) the cam intersection angle.

For example, Patent Document 1 discloses a structure using a cam member having a different cam diameter depending on the engaging optical element.

Japanese Unexamined Patent Publication No. 2001-133673

However, in the structure of Patent Document 1, the larger the weight of the optical element that engages with the cam, the greater the need to increase the cam diameter. However, since the heavy optical element is generally large in the radial direction, the diameter is large. Since the cam member having a large diameter and the optical element having a large diameter overlap each other in the optical axis direction, the size of the device becomes large.

Therefore, an object of the present invention is to provide a drive mechanism that enables the optical element to be driven by a cam member without increasing the size of the device.

The drive mechanism as one aspect of the present invention includes a cam member and a cam provided on the cam member and engaged with an optical element that is movable in the optical axis direction by the cam member. Has a first surface and a second surface, and when the first surface functions as a cam surface, the second surface functions as a cam follower urging surface, and the second surface functions as a cam surface. The first surface functions as a cam follower urging surface.

Other objects and features of the present invention will be described in the following embodiments.

According to the present invention, it is possible to provide a drive mechanism that enables the optical element to be driven by a cam member without increasing the size of the device.

Exploded view of the main part of the lens barrel according to the embodiment of the present invention An exploded perspective view of a main part of a lens barrel according to an embodiment of the present invention. An exploded view of a main part of the lens barrel at the WIDE position according to the embodiment of the present invention. An exploded view of a main part of the lens barrel at the TELE position according to the embodiment of the present invention. An exploded view of a main part of the lens barrel according to the conventional example 1 of the present invention. An exploded view of a main part of the lens barrel according to the conventional example 1 of the present invention. An exploded view of a main part of the lens barrel according to the conventional example 2 of the present invention. An exploded view of a main part of the lens barrel according to the conventional example 2 of the present invention. Detailed view of the cam cylinder member according to the embodiment of the present invention at the MIDDLE-WIDE position. Detailed view of the cam cylinder member at the MIDDLE-TELE position according to the embodiment of the present invention. An imaging device including a lens barrel according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Hereinafter, the lens barrel according to the embodiment of the present invention will be described with reference to FIGS. 1 to 10.

FIG. 1 is an exploded view of a main part of a lens barrel according to an embodiment of the present invention.

The optical system 5 of the lens barrel is composed of a first lens 1, a second lens 2, a third lens 3, and a focus lens group (not shown), and light rays passing through these lens groups are arranged on the optical axis O. An image is formed by the image pickup element 4 and an image is taken.

FIG. 2 is an exploded perspective view of a main part of the lens barrel according to the embodiment of the present invention.

The first lens 1 is held in the first group lens frame 10. The first group lens frame 10 is guided and supported by the first group guide member 81 so as to be movable in the optical axis direction. The first group moving frame 10 is also engaged with the first group rotation stop support member 83. The first group moving frame 10 is supported so that the center of the first lens 1, which is a holding optical element, is located on the optical axis O.

The second lens 2 is held in the second group lens frame 20. Further, the third lens 3 is held in the third group lens frame 30. The second group lens frame 20 and the third group lens frame 30 are guided and supported by the second and third group guide members 82 so as to be movable in the optical axis direction. The second group lens frame 20 and the third group lens frame 30 are also engaged with the second group third group rotation stop support member 84. The second group lens frame 20 and the third group lens frame 30 are supported so that the centers of the second lens 2 and the third lens 3, which are the optical elements held by each, are located on the optical axis O. ..

The first group guide member 81, the second group guide member 82, the first group rotation stop support member 83, and the second group third group rotation stop support member 84 are held by the front side housing member 60 and the rear side housing member 70. ing. Further, the image sensor 4 is held by the rear housing member 70.

The front housing member 60 is provided with a front cam holding portion 61. The front housing member 60 rotatably holds the cam member 90 with respect to the cam rotation axis X together with the rear cam holding portion 71 provided on the rear housing member 70.

The cam member 90 is a side cam cylinder having an axis parallel to the optical axis of the optical system as a rotation axis. The cam member 90 has a first group cam 901 and a second third group cam portion 902, both of which are rib cams. The first group cam 901 is composed of a first cam surface 901a (first surface) and a second cam surface 901b (second surface), which are side surfaces thereof. The second group cam portion 902 is composed of a second group cam surface 902a and a third group cam surface 902b, which are side surfaces thereof.

The first group lens frame 10 is engaged with the first group cam 901 via the first group front cam follower 100 (first cam follower) or the first group rear cam follower 105 (second cam follower).

The first group front cam follower 100 includes a first group front cam engaging member 101 (first cam engaging portion), a first group front slider portion 102 (first slider portion), and a first group slider spring 103 (first group slider spring 103). 1 spring portion) and a first group front cam urging member 104 (first cam engaging urging portion). The group 1 front cam urging member 104 is guided and held by the group 1 front slider portion 102 so as to be relatively separated and approachable from the group 1 front cam engaging member 101, and the group 1 front cam is held. It is urged by the tension of the first group slider spring 103 in the direction approaching the engaging member 101 (the guiding direction of the first group front slider portion 102). By this urging, the first group front cam engaging member 101 and the first group front cam urging member 104 sandwich the first group cam 901 between two side surfaces. As a result, the first group front cam follower 100 and the first group cam 901 are engaged with each other.

The first group rear cam follower 105 includes a first group rear cam engaging member 106 (second cam engaging portion), a first group rear slider portion 107 (second slider portion), and a first group slider spring 103 (first group slider spring 103). 2 spring portion) and a first group rear cam urging member 108 (second cam engaging urging portion). The first group rear cam urging member 108 is guided and held by the first group rear slider portion 107 so as to be relatively separated and approachable from the first group rear cam engaging member 106, and the first group rear cam. It is urged by the tension of the first group slider spring 103 in the direction approaching the engaging member 106 (the guiding direction of the first group rear slider portion 107). By this urging, the first group rear cam engaging member 106 and the first group rear cam urging member 108 sandwich the first group cam 901 between two side surfaces. As a result, the rear cam follower 105 of the first group and the cam 901 of the first group are engaged with each other.

The second group lens frame 20 is engaged with the second group cam surface 902a by the second group cam engaging member 201. The third group lens frame 30 is engaged with the third group cam surface 902b by the third group cam engaging member 301. The second and third group urging members 200 are engaged with the second group lens frame 20 and the third group lens frame 30. The second and third group urging members 200 urge the two groups to approach each other in the optical axis direction, so that the two groups are engaged with each cam surface.

The cam member 90 has a gear portion 900. The cam member 90 rotates about the cam rotation axis X by the driving force of the drive unit 50 when the pinion gear 51 of the drive unit 50 held by the rear housing member 70 and the gear unit 900 engage with each other.

Therefore, the first group lens frame 10, the second group lens frame 20, and the third group lens frame 30 move in the optical axis direction as the cam member 90 rotates due to the driving force of the drive unit 50.

FIG. 3 is an exploded view of a main part of the lens barrel at the WIDE position according to the embodiment of the present invention. In the area of WIDE-MIDDLE, the engagement between the first group lens frame 10 and the first group cam 901 is performed by the first group front cam follower 100. At this time, the first group rear cam follower 105 does not engage with the first group cam 901.

FIG. 4 is an exploded view of a main part of the lens barrel according to the embodiment of the present invention at the TELE position. In the region of MIDDLE-TELE, the engagement between the first group lens frame 10 and the first group cam 901 is performed by the first group rear cam follower 105. At this time, the first group front cam follower 100 does not engage with the first group cam 901.

Thus, when the first group cam 901 engages with one of the first group front cam follower 100 and the first group rear cam follower 105, the first group cam 901 is the first group front cam follower 100 and the first group rear cam follower. It does not engage with the other of 105. The configuration of the lens barrel according to the conventional example will be described below.

FIG. 5 is an exploded view of a main part of the lens barrel according to the conventional example 1 of the present invention. The basic configuration is the same as that of the lens barrel in the embodiment, and the optical system is composed of a first lens 1, a second lens 2, a third lens 3, and a focus lens group (not shown), and light rays passing through these lens groups. However, an image is formed by the image pickup element 4 arranged on the optical axis O, and an image is taken.

FIG. 6 is an exploded view of a main part of the lens barrel according to the conventional example 1 of the present invention. The configuration is as seen from the opposite direction of the paper surface in FIG. The first lens 1 is held in the first group lens frame 11. The first group lens frame 11 is guided and supported by the first group guide member 81 so as to be movable in the optical axis direction. The first group moving frame 11 is also engaged with the first group rotation stop support member 83. The first group moving frame 11 is supported so that the center of the first lens 1, which is a holding optical element, is located on the optical axis O.

The second lens 2 is held in the second group lens frame 21. Further, the third lens 3 is held in the third group lens frame 31. The second group lens frame 21 and the third group lens frame 31 are guided and supported by the second and third group guide members 82 so as to be movable in the optical axis direction. The second group lens frame 21 and the third group lens frame 31 are also engaged with the second group third group rotation stop support member 84. The second group lens frame 21 and the third group lens frame 31 are supported so that the centers of the second lens 2 and the third lens 3, which are the optical elements held by each, are located on the optical axis O. ..

The first group guide member 81, the second group guide member 82, the first group rotation stop support member 83, and the second group third group rotation stop support member 84 are held by the front side housing member 62 and the rear side housing member 72. ing. Further, the image sensor 4 is held by the rear housing member 72.

The front housing member 62 is provided with a front cam holding portion 63. The front housing member 62 rotatably holds the cam member 91 with respect to the cam rotation axis X together with the rear cam holding portion 73 provided on the rear housing member 72.

The cam member 91 has a first group cam 911 and a second group third group cam portion 912. The first group cam 911 is composed of the first group cam surface 911a and the first group urging surface 911b, and the second group third cam portion 912 is composed of the second group cam surface 912a and the third group cam surface 912b. Will be done.

The first group lens frame 11 is engaged with the first group cam 911 at the first group cam follower 110.

The first group cam follower 110 is composed of a first group cam engaging member 111, a first group slider portion 112, a first group slider spring 113, and a first group cam urging member 114. The first group cam urging member 114 is held by the first group slider portion 112 so as to be separated and approachable from the first group cam engaging member 111, and is oriented toward approaching the first group cam engaging member 111. Is urged by the first group slider spring 113.

Due to the above urging force, the first group cam engaging member 111 is in contact with the first group cam surface 911a, and the first group cam urging member 114 is in contact with the first group urging surface 911b. That is, the first group cam engaging member 111 and the first group cam urging member 114 sandwich the first group cam 911. As a result, the first group cam follower 110 and the first group cam 911 are engaged with each other.

The second group lens frame 21 is engaged with the second group cam surface 912a by the second group cam engaging member 211. The third group lens frame 31 is engaged with the third group cam surface 912b by the third group cam engaging member 311. The 2nd and 3rd group urging members 210 are engaged with the 2nd group lens frame 21 and the 3rd group lens frame 31, and the 2nd and 3rd group urging members 210 move the two groups in the optical axis direction. Erect in the direction of approaching. As a result, each cam surface is engaged.

The cam member 91 has a gear portion 910. The cam member 91 rotates about the cam rotation axis X by the driving force of the drive unit 52 when the pinion gear 53 of the drive unit 52 held by the rear housing member 72 and the gear unit 910 engage with each other.

In Conventional Example 1, the diameter of the cam member 91 is designed to be small from the viewpoint of miniaturization. However, as described above, since the magnitude of the driving load with respect to the cam rotation is substantially inversely proportional to the magnitude of the cam diameter, a large driving force is required in the configuration of the conventional example 1. Therefore, the drive unit 52 of the conventional example 1 is larger than the drive unit 50 of the embodiment, and the lens barrel using the drive unit 52 becomes large as a device.

FIG. 7 is an exploded view of a main part of the lens barrel according to the conventional example 2 of the present invention. The basic configuration is the same as that of the lens barrels of Examples and Conventional Example 1, and the optical system is composed of a first lens 1, a second lens 2, a third lens 3, and a focus lens group (not shown), and these lenses are used. The light rays passing through the group are imaged by the image pickup element 4 arranged on the optical axis O, and an image is taken.

FIG. 8 is an exploded view of a main part of the lens barrel according to the conventional example 2 of the present invention. The configuration is as seen from the opposite direction of the paper surface in FIG. 7. The first lens 1 is held in the group 1 lens frame 12. The first group lens frame 12 is guided and supported by the first group guide member 81 so as to be movable in the optical axis direction. The first group moving frame 12 is also engaged with the first group rotation stop support member 83, and the center of the first lens 1 which is an optical element held by the first group moving frame 12 is on the optical axis O. It is supported to be located in.

The second lens 2 is held by the second group lens frame 22. Further, the third lens 3 is held by the third group lens frame 32. The second group lens frame 22 and the third group lens frame 32 are guided and supported by the second and third group guide members 82 so as to be movable in the optical axis direction. The second group lens frame 22 and the third group lens frame 32 are also engaged with the second group third group rotation stop support member 84. The second group lens frame 22 and the third group lens frame 32 are supported so that the centers of the second lens 2 and the third lens 3, which are the optical elements held by each, are located on the optical axis O. ..

The first group guide member 81, the second group guide member 82, the first group rotation stop support member 83, and the second group third group rotation stop support member 84 are held by the front side housing member 64 and the rear side housing member 74. ing. Further, the image sensor 4 is held by the rear housing member 74.

The front housing member 64 is provided with a front cam holding portion 65. The front housing member 64 rotatably holds the cam member 92 with respect to the cam rotation axis X together with the rear cam holding portion 75 provided on the rear housing member 74.

The cam member 92 has a first group cam 921 and a second group third group cam portion 922. The second group third group cam portion 922 is composed of a second group cam surface 922a and a third group cam surface 922b.

The first group lens frame 12 is engaged with the first group cam 921 at the first group cam follower 120.

The first group cam follower 120 is composed of a first group cam engaging member 121, a first group slider portion 122, a first group slider spring 123, and a first group cam urging member 124. The first group cam urging member 124 is held by the first group slider portion 122 so as to be separated and approachable from the first group cam engaging member 121, and is oriented toward approaching the first group cam engaging member 121. Is urged by the first group slider spring 123.

Due to the above urging force, the first group cam engaging member 121 is in contact with the first group cam surface 921a, and the first group cam urging member 124 is in contact with the first group urging surface 921b. That is, the first group cam engaging member 121 and the first group cam urging member 124 sandwich the first group cam 921. As a result, the first group cam follower 120 and the first group cam 921 are engaged with each other.

The second group lens frame 22 is engaged with the second group cam surface 922a by the second group cam engaging member 221. The third group lens frame 32 is engaged with the third group cam surface 922b by the third group cam engaging member 321. The 2nd and 3rd group urging members 220 are engaged with the 2nd group lens frame 22 and the 3rd group lens frame 32, and the 2nd and 3rd group urging members 220 move the two groups in the optical axis direction. Erect in the direction of approaching. As a result, each cam surface is engaged.

The cam member 92 has a gear portion 920. The cam member 92 rotates about the cam rotation axis X by the driving force of the drive unit 50 when the pinion gear 51 of the drive unit 50 held by the rear housing member 74 and the gear unit 920 engage with each other.

In Conventional Example 2, the diameter of the cam member 92 is designed to be large from the viewpoint of reducing the drive load. Therefore, since the drive unit 50 of the conventional example 2 may be smaller than the drive unit 52 of the conventional example 1, the size of the periphery of the drive unit is not increased. However, since the cam member 92 has a large diameter over the entire optical axis direction, the device as a whole becomes large.

In the lens barrel of the embodiment, the diameter of the cam member 90 is increased from the viewpoint of reducing the drive load, so that the drive unit 50 may be small, and the periphery of the drive unit is smaller than that of the conventional example 1.

Further, in the 1st group cam 901 in the embodiment, regarding the cam locus between WIDE and TELE of the 1st group lens frame 10, the region between WIDE and MIDDLE is the first cam surface 901a, and the region between MIDDLE and TELE is the second. Since the cam surface 901b is evenly divided into two and two surfaces of one rib cam are used, the size of the group 1 cam 901 in the optical axis direction may be halved as compared with the conventional example 1 and the conventional example 2. Therefore, it is smaller in the optical axis direction around the cam than in the conventional example 1 and the conventional example 2.

FIG. 9 is a detailed view of the cam cylinder member at the MIDDLE-WIDE position according to the embodiment of the present invention. FIG. 9A shows a cam engagement state at the MIDDLE position closer to WIDE. In this state, only the first group front cam follower 100 is engaged with the first group cam 901, and the first group rear cam follower 105 is not engaged with the first group cam 901.

FIG. 9 (b) shows the state of the position on the TELE side with respect to FIG. 9 (a). At this time, the first group rear cam urging member 108 of the first group rear cam follower 105 does not touch the first group cam 901, but the first group rear cam engaging member 106 is the cam of the first group cam 901. It is in contact with the engagement guide portion 901c (guide portion). The cam engagement guide portion 901c is a tapered surface whose width becomes narrower as it is separated from the second cam surface 901b in the optical axis direction, and the first group lens frame 10 is located near the MIDDLE position from the WIDE side to the TELE side. The first group rear cam engaging member 106 is guided to engage with the second cam surface 901b when moving to.

FIG. 9 (c) further shows the state of the TELE position as compared with FIG. 9 (b). At this time, the first group rear cam engaging member 106 of the first group rear cam follower 105 is in contact with the cam engaging guide portion 901c of the first group cam 901, and the first group rear cam urging member 108 is in contact with the cam engaging guide portion 901c. It is in contact with the urging member guide portion 901d (guide portion) of the first group cam 901. The urging member guide portion 901d is a tapered surface whose width becomes narrower as it is separated from the first cam surface 901a in the optical axis direction, and the first group lens frame 10 is located near the MIDDLE position from the WIDE side to the TELE side. The first group rear cam urging member 108 is guided to engage with the first cam surface 901a when moving to.

Due to these series of behaviors, the first group rear cam follower 105 and the first group cam 901 are smoothly engaged with each other.

In the region on the WIDE side of the state of FIG. 9C, the first cam surface 901a functions as a cam surface, and the second cam surface 901b uses the first group front cam follower 100 as the first group cam. It functions as a cam follower urging surface for engaging with 901.

In the state of FIG. 9A, the fall-prevention shape portion 901e (fall-off prevention portion) is formed between the first-group rear cam engaging member 106 and the first-group rear cam urging member 108 of the first-group rear cam follower 105. It is positioned to prevent the rear cam follower 105 of the first group from falling off from the cam 901 of the first group due to an impact or the like. The fall-out prevention shape portion 901e is provided in a region opposite to the first and second cam surfaces with respect to the cam engagement guide portion 901c and the urging member guide portion 901d. For example, the cam engagement guide portion 901c is provided. It also has a rectangular shape with the shortest width of the tapered surface of the urging member guide portion 901d.

FIG. 10 is a detailed view of the cam cylinder member at the MIDDLE-TELE position according to the embodiment of the present invention. FIG. 10 (c) further shows the state of the TELE position as compared with FIG. 9 (c). At this time, the first group front cam engaging portion 101 of the first group front cam follower 100 is in contact with the cam engaging guide portion 901c of the first group cam 901, and the first group front cam urging member 104 is in contact with the cam engaging guide portion 901c. It is in contact with the urging member guide portion 901d of the first group cam 901. The urging member guide portion 901d is a tapered surface whose width becomes narrower as it is separated from the second cam surface 901b in the optical axis direction, and the first group lens frame 10 is located near the MIDDLE position from the WIDE side to the TELE side. It guides that the engagement between the first group front cam urging member 104 and the second cam surface 901b is smoothly disengaged when moving to.

FIG. 10 (b) shows the state of the position on the TELE side further than that of FIG. 10 (c). At this time, the first group front cam urging member 104 of the first group front cam follower 100 does not touch the first group cam 901, but the first group front cam engaging portion 101 is the cam of the first group cam 901. It is in contact with the engagement guide portion 901c. The cam engagement guide portion 901c is a tapered surface whose width becomes narrower as it is separated from the first cam surface 901a in the optical axis direction, and the first group lens frame 10 is from the WIDE side to the TELE side near the MIDDLE position. It guides that the engagement between the first group front cam engaging member 101 and the first cam surface 901a is smoothly disengaged when moving to.

FIG. 10 (a) shows the state of the position on the TELE side further than that of FIG. 10 (b). In this state, only the first group rear cam follower 105 is engaged with the first group cam 901, and the first group front cam follower 100 is not engaged with the first group cam 901.

Due to these series of behaviors, the engagement between the first group front cam follower 100 and the first group cam 901 can be smoothly disengaged.

In the region on the TELE side of the state of FIG. 10C, the second cam surface 901b functions as a cam surface, and the first cam surface 901a uses the first group rear cam follower 105 as the first group cam. It functions as a cam follower urging surface for engaging with 901.

In the state of FIG. 10A, the dropout prevention shape portion 901e is located between the first group front cam engaging member 101 of the first group front cam follower 100 and the first group front cam urging member 104. , The first group front cam follower 100 is prevented from falling off from the first group cam 901 due to an impact or the like.

The above is the engagement of the first group rear cam follower 105 and the first group cam 901 when the first group lens frame 10 moves from the WIDE side to the TELE side, and the first group front cam follower 100 and the first group cam 901. Although the disengagement has been described, these mechanisms are symmetrical with respect to the optical axis direction, and show the same behavior when the first group lens frame 10 moves from the TELE side to the WIDE side.

When the first group lens frame 10 moves from the TELE side to the WIDE side in the vicinity of MIDDLE, the first group front cam engaging member 101 is smoothly guided by the cam engaging guide portion 901c and the first cam surface 901a. The first group front cam urging member 104 smoothly engages with the second cam surface 901b while being guided by the urging member guide portion 901d. Further, the first group rear cam engaging member 106 is smoothly disengaged from the second cam surface 901b while being guided by the cam engaging guide portion 901c, and the first group rear cam urging member 108 is attached. The engagement with the first cam surface 901a is smoothly disengaged while being guided by the force member guide portion 901d.

As described above, it is possible to drive a plurality of optical elements by the cam member without increasing the size of the device.
[Imaging device]
Next, an example of an image pickup apparatus using the lens barrel of the present invention will be described with reference to FIG. In FIG. 11, 1000 is the camera body, and 1100 is the lens barrel described in the embodiment. Reference numeral 4 denotes an image pickup element (photoelectric conversion element) such as a CCD sensor or a CMOS sensor, which is built in a camera body and receives an optical image formed by an optical system in a lens barrel 1100 and performs photoelectric conversion. The camera body 1000 may be a so-called single-lens reflex camera having a quick turn mirror, or a so-called mirrorless camera having no quick turn mirror.

By applying the lens barrel of the present invention to an imaging device such as a digital still camera in this way, it is possible to obtain an imaging device having a small lens.

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 modifications can be made within the scope of the gist thereof. Further, the configuration is not limited as long as the configuration considers the design function.

90 Cam member 901 Cam 901a First surface 901b Second surface

Claims (13)

With the cam member
It has a cam that is provided on the cam member and engages with an optical element that is movable in the optical axis direction by the cam member.
The cam has a first surface and a second surface.
When the first surface functions as a cam surface, the second surface functions as a cam follower urging surface.
A drive mechanism characterized in that when the second surface functions as a cam surface, the first surface functions as a cam follower urging surface. The optical element engages the cam via a first cam follower or a second cam follower.
The drive according to claim 1, wherein when the cam engages with one of the first and second cam followers, the cam does not engage with the other of the first and second cam followers. mechanism. The drive mechanism according to claim 2, wherein the cam has a guide portion for smoothly switching the engagement between the first cam follower and the second cam follower. The drive mechanism according to claim 3, wherein the guide portion is a tapered surface whose width becomes narrower as the distance from the first and second surfaces increases in the optical axis direction. 2. The cam is characterized by having a dropout prevention portion for preventing the cam from falling off when either one of the first cam follower and the second cam follower is disengaged. The drive mechanism according to any one of 4 to 4. The drive mechanism according to claim 5, wherein the fall-out prevention portion is provided in a region opposite to the cam surface with respect to the guide portion. The drive mechanism according to claim 6, wherein the fall-out prevention portion has a rectangular shape. The drive mechanism according to any one of claims 1 to 7, wherein the cam member is a side cam cylinder having an axis parallel to the optical axis of the optical element as a rotation axis. The drive mechanism according to claim 1 to 8, wherein the cam is a rib cam. The drive mechanism according to claim 9, wherein the first and second surfaces are two surfaces of the rib cam. In the first cam follower, the first cam engaging portion, the first cam engaging urging portion, and the first cam engaging urging portion are relative to the first cam engaging portion. The first slider portion that guides the first cam engaging urging portion so as to be movable, the first cam engaging portion and the first cam engaging urging portion are referred to as the first slider portion. It is composed of a first spring part that is urged by tension with respect to the guiding direction of.
In the second cam follower, the second cam engaging portion, the second cam engaging urging portion, and the second cam engaging urging portion are relative to the second cam engaging portion. A second slider portion that guides the second cam engaging urging portion so as to be movable, the second cam engaging portion and the second cam engaging urging portion are referred to as the second slider portion. It is composed of a second spring part that is urged by tension with respect to the guiding direction of.
When the first cam engaging portion engages with the cam surface, the spring portion urges the first cam engaging urging portion to the cam follower urging surface, whereby the first cam engaging portion is engaged with the cam follower. The cam follower and the cam are urged,
When the second cam engaging portion engages with the cam surface, the second spring portion urges the second cam engaging urging portion to the cam follower urging surface. The drive mechanism according to any one of claims 2 to 7, wherein the second cam follower and the cam are urged. The drive mechanism according to any one of claims 1 to 11.
A lens barrel comprising an optical system having the optical element. The lens barrel according to claim 12 and
An image pickup apparatus comprising: an image pickup device that receives an image formed by the optical system.

Images