JP2020008706A - Les drive device - Google Patents

Abstract

To provide a zoom electric drive of an interchangeable lens including an existing lens without providing the interchangeable lens with a screw hole and without requiring positioning by a user.SOLUTION: A lens drive device comprises: an interchangeable lens including an operation ring capable of changing photographic magnification by a rotation operation and a first drive transmission part provided on an outer peripheral surface of the operation ring; drive means for generating drive force; a drive unit including a second drive transmission part for transmitting a drive force to the drive means and the first drive transmission part; and at least one annular member removably attached to the interchangeable lens. The drive unit is mounted on the interchangeable lens via the annular member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mounting unit of a drive unit without giving a design restriction to an interchangeable lens.

  In recent years, users of DSLR interchangeable lenses have demanded smooth low-speed zoom such as a video camera using an electric zoom and quick zoom adjustment by remote control. Therefore, an interchangeable lens having an electric zoom function inside the interchangeable lens has been sold in recent years. However, it is difficult to satisfy the zoom performance required by the user due to the restriction on the power supplied from the camera to the lens and the restriction on the size of the driving device that can be mounted inside the lens barrel.

  Therefore, the problem described above can be solved by mounting a drive unit for driving the interchangeable lens from the outside. Further, by making the drive unit detachable by the user, smooth zooming can be performed even with an existing interchangeable lens that has not conventionally been compatible with electric zoom.

  In the drive unit of the prior art document 1, a screw hole is provided from the outer periphery of the interchangeable lens to the inside thereof, and the interchangeable lens is fastened with screws to achieve accuracy and rigidity at the time of attachment.

  However, in the case where the interchangeable lens is provided with a screw hole as in the prior art document 1, the radial size of the interchangeable lens becomes large and the internal structure design becomes difficult, and the versatility including the above-mentioned existing interchangeable lens is realized. You will not be able to do it. The reason for this is that recent interchangeable lenses are electrically driven for focus adjustment, exposure adjustment, and the like, so that the internal structure of the interchangeable lens is complicated and space is small.

  As another mounting example, there has been proposed a device in which a rod is arranged on the bottom surface of a camera and a driving unit is mounted on the rod as in Patent Document 2 to externally drive an interchangeable lens. However, since many components are interposed between the interchangeable lens and the drive unit, there is a problem that it is difficult to adjust the position of the contact portion that transmits the driving force.

JP 2013-15667A JP 2015-49414 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a zoom lens with an interchangeable lens including an existing lens without providing a screw hole in the interchangeable lens and without requiring positioning by a user. The present invention is to provide an electric drive.

In order to achieve the above object, a lens driving device according to the present invention includes:
An operation ring capable of operating an optical element by a rotation operation, an interchangeable lens including a first drive transmission unit provided on an outer peripheral surface of the operation ring, a driving unit for generating a driving force, the driving unit and the first A drive unit including a second drive transmission unit for transmitting a driving force to the drive transmission unit, and a lens driving device including at least one annular member detachable from the interchangeable lens, wherein the drive unit is connected to the drive unit via the annular member. It is characterized by being attached to an interchangeable lens.

  ADVANTAGE OF THE INVENTION According to the lens drive device which concerns on this invention, even if it is an existing interchangeable lens which is not exclusively designed by using a drive unit, the drive transmission member and the annular member detachably prepared for the interchangeable lens, The electric drive can be realized without the alignment adjustment.

Explanatory diagram showing the configuration of a camera system according to the present invention. Explanatory drawing showing the configuration of a lens drive related member in the present invention. Explanatory diagram showing a drive configuration of a drive unit according to the present invention. Sectional drawing which shows the setting method of each member in this invention Explanatory drawing showing a drive unit in the present invention. Explanatory drawing which shows the modification of the mounting method in this invention. Explanatory drawing which shows the modification of the mounting method in this invention. Explanatory drawing which shows the modification of the mounting method in this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  First, the configuration of the lens driving device will be described with reference to FIGS.

  FIG. 1 shows a mounted state of the lens driving device. The camera 1 is an imaging device with interchangeable lenses. The interchangeable lens 2 is a zoom lens. By rotating the operation ring 201, the lens position inside the interchangeable lens 2 is moved, and zoom adjustment of an image taken by the camera 1 can be performed.

  FIG. 2 shows a state in which each member is not mounted. The ring gear portion 501 of the gear ring 5 is provided on the outer periphery of the operation ring 201 such that a reference pitch circle is formed around the operation ring central axis A1.

  The ring member 4 is mounted on the ring member mounting portion 202 of the interchangeable lens 2 using a screw 403. The drive unit 3 is mounted on the annular member 4 by using mounting screws 306.

  FIG. 3 shows the output gear 302 of the drive unit 3 that meshes with the ring gear 501. The output gear shaft A3 is a rotation center shaft of the output gear 302.

  The inter-axis distance R0 shown in FIG. 4 is the sum of the pitch circle radius R1 which is the radius of the reference pitch circle of the output gear 302 and the pitch circle radius R2 which is the radius of the reference pitch circle of the ring gear portion 501. The drive unit 3 is mounted so that the distance between the operation ring center axis A1 and the output gear axis A3 matches the center distance R0. That is, the pitch circle radius R1 and the pitch circle radius R2 circumscribe. The lens driving device of this embodiment is configured such that the pitch circle radii R1 and the pitch circle radii R2 circumscribe when the drive unit 3 is mounted on the interchangeable lens 2 via the annular member 4.

  Next, a method of setting each member for making the pitch circle radius R1 and the pitch circle radius R2 circumscribe will be described with reference to FIG. Here, it is assumed that the drive unit 3 is mounted on not only one type of interchangeable lens 2 but various types of interchangeable lenses. For this reason, the radius R3 of the annular member attachment portion 202 of the interchangeable lens 2 and the radius R4 of the engagement portion between the operation ring 201 and the gear ring inner peripheral portion 502 are different from each other. A method for setting the member 4 will be described.

  In the following description, the center of the inscribed circle of the contact point between the lens engaging portion 402 of the annular member 4 and the annular member mounting portion 202 of the interchangeable lens 2 is defined as the annular member center axis A2. When the ring member 4 is mounted on the interchangeable lens 2, the ring member center axis A2 is disposed at a set position with respect to the operation ring center axis A1. Here, in order to simplify the description, the operation ring center axis A1 and the ring member center axis A2 are set to coincide.

  In FIG. 4, a description will be given on the assumption that the horizontal direction is the x-axis and the vertical direction is the y-axis around the operation ring central axis A1.

  FIG. 4A is an xy sectional view passing through the center of the positioning hole 303. The position of the drive unit 3 in the x direction is determined by the drive unit mounting surface 401 of the annular member 4 and the annular member mounting surface 309 of the drive unit 3. The distance between the ring member mounting surface 309 and the y axis is L1. The position of the drive unit 3 in the y-axis direction is determined by the engagement between the positioning pin 404 of the annular member 4 and the positioning hole 303 of the drive unit 3. The distance between the center of the positioning hole 303 and the x-axis is L2.

  FIG. 4B is an xy cross-sectional view of a meshing portion of the ring gear 501 and the output gear 302. The distance in the x direction from the annular member mounting surface 309 of the drive unit 3 to the output gear axis A3 is L1 ', and the distance in the y direction from the center of the positioning hole 303 to the output gear axis A3 is L2'.

Then, the following equations (1) to (3) hold. This is because the drive unit 3 can be mounted on the interchangeable lens 2 by arbitrarily determining two parameter values among L1, L2 and the pitch circle radius R2, and setting the other one parameter value from the following calculation. Indicates a thing.
L1 = ((R1 + R2) ＾ 2- (L2'-L2) ＾ 2) ＾ (1/2) -L1 '(1)
L2 = ((R1 + R2) ＾ 2- (L1 ′ + L1) ＾ 2) ＾ (１ ／) + L2 ′ (2)
R2 = ((L1 ′ + L1) ＾ 2 + (L2′−L2) ＾ 2) ＾ (1/2) −R1 (3)
Here, an example of a method of selecting two parameters from L1 and L2 and a pitch circle radius R2 and a method of determining the values will be described.

  If L2 is changed for each interchangeable lens, the position of the drive unit 3 shifts in the y direction. Then, holding and operability of the drive unit 3 are changed by the interchangeable lens. To prevent this, it is desirable to set L2 to a fixed value. That is, the first parameter to be selected is L2. L2 is set to an arbitrary value when designing the drive unit 3.

  Next, either L1 or the pitch circle radius R2 is selected.

  The ring member 4 is desirably as small as possible from the viewpoint of carrying and parts costs. For this reason, in this embodiment, parameters are selected in order to satisfy functions and reduce the size.

  The drive unit 3 and the ring member 4 are attached by screw holes 406 and mounting screws 306. Therefore, the depth of the screw hole 406 required for the length of the mounting screw 306 is required. That is, L1 is selected as the second selection parameter. The value is determined to be a minimum value that can secure a necessary depth for the screw hole 406. Then, all values are determined by substituting L1 and L2 into the equation (3) and calculating.

  At this time, it is necessary to pay attention to whether the pitch circle radius R2 obtained from the calculation result of (3) has a margin with respect to R4. That is, if the thickness of the tooth bottom and R4 of the ring gear portion 501 constituted by the pitch circle radius R2 is small, the strength of the ring gear portion 501 cannot be secured, and the transmission efficiency between the output gear 302 and the gear ring 5 decreases. That's why.

  If the strength of the ring gear 501 cannot be ensured as a result of determining L1, the pitch circle radius R2 is used as the second selection parameter instead of L1. Then, the pitch circle radius R2 is determined to a value necessary to secure the strength of the ring gear portion 501. L1 is obtained from the calculation result of (1) in which L2 and the pitch circle radius R2 are substituted. By doing so, an optimal solution that is functionally satisfied while considering the small size is required.

  From these results, the ring gear portion 501 of the gear ring 5 is set to have a pitch circle radius R2 when the ring gear portion 501 is mounted on the operation ring 201 of the interchangeable lens 2.

  The annular member 4 is set so that the distance from the annular member center axis A2 to the drive unit mounting surface 401 is L1.

  If the annular member 4 and the gear ring 5 are designed as selectable accessories according to the interchangeable lens, the drive unit 3 can be easily mounted.

  Further, in an interchangeable lens in which either R3 or R4 has the same value, the annular member 4 or the gear ring 5 can be used as a common accessory. At this time, if R3 is the same, the ring member 4 is used as the common accessory, and if R4 is the same, the gearing 5 is used as a common accessory, and the other is newly designed.

  In the description so far, the setting method of each member for making the pitch circle radius R1 and the pitch circle radius R2 circumscribe has been described. This is only an example to illustrate the subject matter.

  An example of a modification of the present case will be described below.

  In this case, the positioning hole 303 of the drive unit 3, the annular member mounting surface 309, and the mounting screw 306 are used for positioning the drive unit 3. However, as shown in FIG. 6, the positioning between the shafts can also be performed by slidingly mounting the drive unit 3 on the annular member 4 using the key groove portion 408 and the straight key portion 317. In this case, the distances L2 and L2 'described above are obtained by changing the axis center of the positioning hole 303 to the center of the contact point between the straight key portion 317 and the key groove portion 408, thereby using the expressions (1) to (3). Settings are possible.

  Next, in the present case, the lens engaging portion 402 is made to contact the entire periphery of the annular member attaching portion 202. However, when the lens engaging portion 402 is attached to the interchangeable lens 2 which does not assume the attaching of the annular member 4, Operation switches and display means may be provided on the circumference of the annular member mounting surface 309. In that case, the lens engaging portion 402 can be divided and arranged as shown in FIGS. 7 (a) to 7 (c).

  In this case, the drive unit 3 is mounted on the interchangeable lens 2 using one annular member 4. However, depending on the design of the drive unit 3, the annular member mounting surface 309 and the output gear 302 are separated in the direction of the annular member central axis A2, or in the direction of the annular member central axis A2 of the annular member mounting surface 309. May be short. In that case, the moment given by the driving force applied to the output gear 302 to the mounting portion of the drive unit 3 increases. Then, it becomes difficult to maintain the distance R0 between the operation ring central axis A1 and the output gear axis A3. In this case, as shown in FIG. 8, the drive unit 3 is mounted at two places where the gear ring 5 is disposed using the auxiliary annular member 6. Thereby, the distance R0 between the operation ring central axis A1 and the output gear axis A3 can be maintained.

  In this case, the operation ring 201 and the gear ring 5 are provided separately. However, when developing an interchangeable lens on the assumption that the drive unit 3 is mounted, the gear ring 5 may be provided integrally with the operation ring 201.

  In this case, the gear is used for the drive transmission from the drive unit 3 to the operation ring 201, but the drive transmission may be performed by, for example, a frictional force between the cylindrical shapes.

  Various modifications and changes such as division and integration of parts for each function can be made to the various members described in the present case, and such modified forms are included in the technical scope of the present invention.

2 interchangeable lens, 201 operation ring, 202 ring member mounting part,
3 drive unit, 302 output gear, 303 positioning hole,
309 ring member mounting surface, 310 output shaft, 4 ring members,
401 drive unit mounting surface, 402 lens engagement part, 403 fastening screw,
404 positioning pin, 406 screw hole, 5 gear ring, 501 ring gear section,
A1 Operation ring central axis, A2 Ring member central axis, A3 Output gear axis

Claims (10)

An operation ring that can operate the optical element by rotating operation,
An interchangeable lens including a first drive transmission unit provided on the operation ring outer peripheral surface,
Driving means for generating a driving force;
A drive unit including a second drive transmission unit for transmitting a driving force to the drive unit and the first drive transmission unit,
A lens driving device including at least one annular member detachable from the interchangeable lens,
A lens drive device wherein the drive unit is mounted on the interchangeable lens via a ring member. A first arc centered on a rotation axis of the operation ring drawn by a contact point of the first drive transmission unit and the second drive transmission unit in the first drive transmission unit, and a first arc in the second drive transmission unit. A second circular arc centered on a rotation center of the second drive transmission unit drawn by a contact point between the one drive transmission unit and the second drive transmission unit is configured to circumscribe. Item 2. The lens driving device according to item 1. The ring member has a plurality of types having different distances between a rotation axis of an operation ring and a drive unit mounting surface of the ring member in a state where the ring member is mounted on the interchangeable lens, and the ring member can be selected according to the interchangeable lens. The lens driving device according to claim 1 or 2, wherein: The ring member has a plurality of types in which a distance between an inscribed circle formed by an engaging portion of the interchangeable lens and the annular member and a drive unit mounting surface in a state where the ring member is mounted on the interchangeable lens is different. The lens driving device according to claim 1, wherein a ring member can be selected. 3. The lens driving device according to claim 1, wherein the first drive transmission unit is detachable from an operation ring of the interchangeable lens. The first drive transmission unit has a plurality of types having different distances between the outer peripheral portion of the operation ring and the first arc in a state where the first drive transmission unit is mounted on the operation ring. The lens driving device according to claim 1, wherein the lens driving device is selectable. The lens drive device according to claim 1, wherein the first drive transmission unit and the second drive transmission unit have a gear shape having the same pitch. The first arc is a reference pitch circle of a gear shape of a first drive transmission unit, and the second arc is a reference pitch circle of a gear shape of a second drive transmission unit. The lens driving device according to claim 1. 2. The drive unit according to claim 1, wherein the drive unit is mounted on the lens barrel via two annular members disposed so as to sandwich the first drive transmission unit in the first rotation axis direction. 3. Lens driving device. The lens driving device according to claim 1, wherein the annular member includes a contact portion that engages with the lens barrel, and the contact portion has at least two points.