JP2000066081A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily attach a guide member to a coupling member, to improve assembling workability and to produce a lens barrel at low cost by holding the coupling member in a state where its movement in the axial direction of a lens barrel constituting member is regulated. SOLUTION: One guide groove 2b extended in the peripheral direction of a cam barrel 2, and an open groove 2c opening at the rear end face in the axial direction of the inside diameter part of the cam barrel 2 and linked with the groove 2b are formed at the inside diameter part of the cam barrel 2. The coupling member 8 is provided with a disk-like base part 8c where a hole 8d is formed in the center. A small projection 8a whose width in a peripheral direction is small is formed on the upper side of the base part 8c, and a large projection 8b whose width in the peripheral direction is large is formed on the lower side thereof. A hole 8f which a key part 5a enters in the case of assembling a straight advance key ring 5, a flexible guide part, and four holes 8h for screwing are formed at the base part 8c. In the case of attaching the key ring 5 to the cam barrel 2, the large projection 8b of the member 8 is inserted in the guide groove 2b of the cam barrel 2, and then the small projection 8a is inserted in the groove 2b through the groove 2c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lens barrel,
More specifically, the present invention relates to a zoom lens barrel in which a guide member which is fed out integrally with a cam tube is attached to a cam tube which is fed while rotating about an optical axis.

[0002]

2. Description of the Related Art A zoom lens barrel as described above is constructed, for example, as shown in FIGS. Note that the zoom lens barrels in these figures have a differential two-group zoom lens barrel structure.

The fixed barrel 101 houses the entire unit of the present zoom lens barrel. A female helicoid 101 a is formed in the inner diameter portion of the fixed cylinder 101, and holds the cam cylinder 102. A spur-tooth helicoid 102a in which a male helicoid and a spur gear are formed spatially integrally is formed on the imaging surface side of the outer diameter portion of the cam cylinder 102, and the female helicoid 101a of the fixed cylinder 101 and Helicoid binding. A long hole 101 is provided on the side of the fixed cylinder 101.
A driving gear that rotates by receiving power from a power transmission system (not shown) enters into the elongated hole 101b, and meshes with the spur-toothed helicoid 102a of the cam cylinder 102. As a result, the cam barrel 102 receives power in the fixed barrel 101 and extends in the optical axis direction while rotating in the direction of the arrow “Z” in the figure.

[0004] A female helicoid and a cam groove for connecting and holding the front group cylinder 103 and the rear group cylinder 104 are formed in the inner diameter portion of the cam cylinder 102. The front group cylinder 103 houses a front group lens and a shutter mechanism (not shown). A male helicoid 103a is formed on the imaging surface side of the outer diameter portion of the front group cylinder 103, and the cam cylinder 102
And helicoid binding. However, the male helicoid 103a of the front group cylinder 103 is the spur tooth helicoid 1 of the cam cylinder 102.
02a is the reverse lead.

[0005] In addition, the upper and lower two
There are formed three rectilinear grooves 103c and three rectilinear keys 103b, which are keyed to the rectilinear key ring 105 and the rear group cylinder 104, respectively. In the drawing, only one piece is shown by a broken line.

[0006] The rear group barrel 104 holds a rear group lens (not shown). The rear group cylinder 104 has three cam pins 10
4a is implanted and cam-coupled to the cam groove of the cam cylinder 102. Although the cam groove is not shown, the front group cylinder 103
The rear group cylinder 104 is formed to move along a locus that enables shooting by a combination with the inner lens.

The rear barrel 104 is formed with three rectilinear grooves 104b which are keyed to the straight keys 103b of the front barrel 103, and are relatively formed along the optical axis with respect to the front barrel 103. Is non-rotating, but is movable.

In the cam cylinder 102, a straight key ring 10 is provided.
5 is attached via a holding member 108 described later. The straight key ring 105 is non-rotatable about the optical axis with respect to the fixed barrel 101 (rotatable with respect to the cam barrel 102), but moves integrally with the cam barrel 102 in the optical axis direction.

The straight key ring 105 is formed with two upper and lower key portions 105a extending forward and two guide portions 105b projecting from the outer diameter portion. Key part 105a
Is keyed to the straight groove 103c of the front group cylinder 103. The guide portion 105b is keyed to a rectilinear groove 101c formed on the inner surface of the fixed cylinder 101. Thereby, the front group cylinder 103 is linearly guided in the optical axis direction.
Therefore, the front group cylinder 103 can move in the optical axis direction without rotating with respect to the fixed cylinder 101, and the rear group cylinder 104, which is keyed to the front group cylinder 103, has the same relationship with the fixed cylinder 101. become.

Further, a flexible guide portion 105e is formed on a side surface of the straight key ring 105. The flexible guide portion 105e is configured such that a flexible printed board that transmits an electric control signal to a shutter mechanism or the like housed in the front group cylinder 103 extends from the front group cylinder 103 through the cam cylinder 102 to the outside of the fixed cylinder 101. When the cam barrel 10
The second spur tooth helicoid 102a is guided so as not to bite. In this case, the escape portion 101 is provided on the inner surface of the fixed cylinder 101 so as not to interfere with the flexible guide portion 105e.
d is formed.

Behind the straight key ring 105, a thin diaphragm plate 106 is fixed by screws 107.
As the zoom mechanism, the aperture plate 106 is an unnecessary member. However, if the linear key ring 105 requires a certain degree of rigidity and the thickness of the linear key ring 105 is large, the end face of the hole 105 c opened for the photographing optical path is required. At 105d, the photographing light is reflected, which adversely affects the photographing screen. For this reason, an aperture plate 106 having a small plate thickness and low end face reflection is required.

In front of the straight key ring 105, two holding members 108 are fixed integrally with the aperture plate 106 by screws 107. The holding member 108 is a cam cylinder 1
02 guide groove 102 cut in the circumferential direction of the inner diameter of 02
b. As a result, the rectilinear key ring 105 is rotatable relative to the cam barrel 102, but moves integrally in the optical axis direction. Since the holding member 108 is engaged with the guide groove 102b formed on the inner surface of the cam cylinder 102, the straight key ring 10
Numeral 5 is rotatable with respect to the cam cylinder 102 in any rotational phase, and moves integrally with the cam cylinder 102 in the optical axis direction.

In the lens barrel configured as described above,
When the cam cylinder 102 rotates in the direction of the arrow “Z” by the power (not shown) and extends from the fixed cylinder 101, the front group cylinder 103 and the rear group cylinder 104 simultaneously extend so as to satisfy a predetermined optical condition.

[0014]

However, when the straight key ring 105 is attached to the cam barrel 102 as described above, the 2
The following problem occurs in the configuration using one holding member 108.

In order to attach the straight key ring 105 to the cam cylinder 102, first, two holding members 108 are inserted into the guide grooves 102b of the cam cylinder 102, and then the straight key ring 105 is inserted into the cam cylinder 102, and the holding member 1
08, the holding member 108 is suspended in the air until the holding member 108 is inserted into the guide groove 102b and the straight key ring 105 is screwed. It will come off. Further, although the positions of the screw holes of the straight key ring 105 are determined, since there are two holding members 108, if the insertion phases of the guide grooves 102b are not exactly aligned in the opposite 180 ° direction, the screw with the straight key ring 105 may be screwed. The screw cannot be fixed because the hole does not fit. Thus, there is a problem that the assemblability is extremely poor.

In addition, metal is often used for the holding member 108 because of its strength. In this case, it is necessary to perform tapping in advance, and it is possible to perform self-tap assembling on plastic parts. However, there is a problem that the cost increases.

Further, even if the holding member 108 is made of a plastic part, since the self-tap assembly is performed by pressing the screw in the thrust direction and rotating the screw, the holding member can be assembled in the above-mentioned floating state. 108
In this case, the workability is significantly deteriorated.

[0018] The necessity of two holding members 108 itself leads to an increase in the number of parts.

[0019]

In order to solve the above-mentioned problems, according to the present invention, there is provided a cylindrical lens barrel member (for example, a cam barrel) and another member disposed inside the lens barrel member. A guide member that guides a lens barrel constituent member (for example, a lens holding member) in the axial direction, and a disc-shaped coupling member that is attached to the inner diameter portion of the lens barrel constituent member and that is integrally coupled with the guide member are provided. A first projection on the outer diameter portion of the coupling member and the first projection
A second protrusion having a width in the circumferential direction larger than the protrusion is formed, and a fitting groove extending in the circumferential direction to fit the first and second protrusions in the inner diameter portion of the lens barrel constituent member; An opening groove is formed at the axial end face, is connected to the fitting groove, and has an opening groove having a groove width not less than the width of the first protrusion and smaller than the width of the second protrusion.

When assembling the lens barrel configured as described above, first, the second groove of the coupling member is fitted into the fitting groove of the lens barrel constituent member.
The projection (wide projection) is inserted, and then the first projection (narrow projection) is inserted into the fitting groove through the opening groove. This allows
The coupling member is held by the lens barrel constituent member in a state where movement is restricted at least on the subject side in the optical axis direction of the lens barrel constituent member. For this reason, the guide member can be easily attached to the coupling member by self-tapping or the like. Therefore, it is possible to realize a lens barrel that is easy to assemble and can be manufactured at low cost.

Further, in a phase other than the rotational phase when the coupling member is incorporated into the lens barrel constituent member, the coupling member moves with respect to the lens barrel constituent member in both directions of the object side and the image plane in the optical axis direction. You are in a regulated state. That is, the coupling member is held so as to move integrally with the movement of the lens barrel constituent member in the optical axis direction.

The above-mentioned invention is directed to a fixed cylinder fixed to the camera body, a cam portion or a helicoid screw which can rotate at least with respect to the fixed cylinder and axially drives a lens holding member disposed inside. A cam cylinder having a portion, a coupling member rotatably attached to the cam cylinder, and a guide member axially guiding a lens holding member integrally coupled to the coupling member and driven by rotation of the cam cylinder. This can be applied to a lens barrel having the following.
In this case, a fitting groove extending in the circumferential direction to fit the first and second projections of the coupling member so as to be movable in the rotation direction is formed in the inner diameter portion of the cam cylinder, and an opening is formed in the axial end surface of the inner diameter portion. To form an opening groove connected to the fitting groove, and in the assembling procedure described above,
What is necessary is just to attach a coupling member and a guide member to a cam cylinder.

In the invention described above, the guide member is guided by the guide member and the guide member by restricting radial movement of the guide member by radially fitting the guide member to the inner diameter portion of the lens barrel constituting member (cam cylinder). It is desirable that the optical axis of a lens holding member or the like can be easily adjusted.

Further, it is desirable that the coupling member is formed in a disk shape and a diaphragm opening is formed at the center thereof so that the occurrence of flare or the like can be prevented without providing a separate diaphragm member.

[0025]

FIG. 1 is an exploded view of a zoom lens barrel according to a first embodiment of the present invention. The fixed barrel 1 houses the entire unit of the present zoom lens barrel. A female helicoid 1a is formed on the inner diameter of the fixed barrel 1. The fixed barrel 1 holds a cam barrel (a lens barrel constituting member in the claims) 2 inside.
A spur-tooth helicoid 2a in which a male helicoid and a spur gear are formed integrally spatially is formed on the imaging surface side of the outer diameter portion of the cam cylinder 2, and the female helicoid 1a of the fixed cylinder 1 is formed.
Helicoidally bound to a.

An elongated hole 1b is formed in the side surface of the fixed cylinder 1. A driving gear that rotates by receiving power from a power transmission system (not shown) enters into the elongated hole 1b. It meshes with the tooth helicoid 2a. As a result, the cam barrel 2 receives the power in the fixed barrel 1 and extends in the optical axis direction while rotating in the direction of the arrow “Z” in the figure.

Further, a female helicoid and a cam groove for connecting and holding the front group cylinder 3 and the rear group cylinder 4 are formed in the inner diameter portion of the cam cylinder 2. The front group cylinder 3 houses a front group lens and a shutter mechanism (not shown). A male helicoid 3 a is formed on the imaging surface side of the outer diameter portion of the front group cylinder 3, and is helicoidally coupled to the cam cylinder 2. However, the male helicoid 3a of the front group cylinder 3 has a lead opposite to that of the spur tooth helicoid 2a of the cam cylinder 2.

In the inner diameter part of the front group cylinder 3, there are formed two upper and lower rectilinear grooves 3c and three rectilinear keys 3b.
Each is keyed to a straight key ring (a guide member in the claims) 5 and a rear group cylinder 4. In the drawing, only one piece is shown by a broken line.

The rear group cylinder 4 holds a rear group lens (not shown). Three cam pins 4 a are implanted in the rear group cylinder 4, and are cam-coupled to the cam grooves of the cam cylinder 2. Although not shown, the cam groove is formed so as to move the rear group cylinder 4 along a locus that enables photographing by combination with the lens in the front group cylinder 3.

The rear cylinder 4 has three rectilinear grooves 4b for key connection with the rectilinear keys 3b of the front cylinder 3.
It is relatively non-rotatable with respect to the front group cylinder 3 along the optical axis, but is movable.

A straight key ring 5 is mounted in the cam cylinder 2 via a connecting member 8 described later. The straight key ring 5 is non-rotatable about the optical axis with respect to the fixed barrel 1 (rotatable with respect to the cam barrel 2), but moves integrally with the cam barrel 2 in the optical axis direction.

The straight key ring 5 is formed with two upper and lower key portions 5a extending forward and two left and right guide portions 5b projecting from the outer diameter portion. The key portion 5a is keyed to the rectilinear groove 3c of the front group cylinder 3. Guide section 5b
Is keyed to a rectilinear groove 1c formed in the inner surface of the fixed cylinder 1. Thereby, the front group cylinder 3 is linearly guided in the optical axis direction. Accordingly, the front group cylinder 3 can be moved in the optical axis direction without rotating with respect to the fixed cylinder 1, and the rear group cylinder 4 keyed to the front group cylinder 3 has the same relationship with the fixed cylinder 1. become.

In the lens barrel configured as described above,
When the cam barrel 2 rotates in the direction of the arrow "Z" by the power (not shown) and extends from the fixed barrel 1, the front group cylinder 3 and the rear group cylinder 4 simultaneously extend so as to satisfy predetermined optical conditions.

Next, the mounting structure of the straight key ring 5 to the cam cylinder 2 will be described in detail with reference to FIGS.

A single guide groove (fitting groove) 2b extending in the circumferential direction is formed in the inner diameter portion of the cam cylinder 2. An opening groove 2c is formed in the inner diameter portion of the cam cylinder 2 and opens at the rear end face in the axial direction of the inner diameter portion and is connected to the guide groove 2b. Here, as shown in FIG. 5, the width of the opening groove 2c is A, the inner diameter of the bottom surface of the guide groove 2b is φB, and the inner diameter of the edge portion 2d in the inner diameter portion of the cam cylinder 2 is φC.

The straight key ring 5 is configured as described above. Here, as shown in FIG. 7, the circular diameter of the base 5c of the straight key ring 5 is φH. The circular diameter φH of the base 5c and the inner diameter φC of the edge 2d of the cam cylinder 2
And φC = φH (). For this reason, as shown in FIG. 4, when the straight key ring 5 is incorporated in the cam cylinder 2, the base 5 c is
Diameter fitting to d.

The straight key ring 5 of the present embodiment is not provided with a flexible guide portion, but is provided with a flexible guide portion on a connecting member 8 described later. The base 5c of the straight key ring 5 has a hole for transmitting photographing light, and screw holes 5d arranged at four places around the hole.
Are formed.

The coupling member 8 has a disk-shaped base 8c having a hole 5c formed in the center. A small projection 8a having a small circumferential width is formed on the upper side of the base 8c.
On the lower side, a large projection 8b having a large circumferential width is formed. Here, as shown in FIG. 6, the outer diameter of the base 8c is φ
G, the width of the small projection 8a is D, the width of the large projection 8b is E, and the outer diameter of the small projection 8a and the large projection 8b is φF. E> A ≧ D () φB>φF>φC> φG () The dimensions of each part are determined so as to satisfy the relationship.

The end face 8e of the aperture 8d formed at the center of the base 8c is formed as a slope closer to the optical axis as it approaches the image plane in the optical axis direction. Thus, the same function as the aperture plate (106 in FIG. 9) can be performed on the coupling member 8, so that the number of components can be reduced as compared with the case where an additional aperture plate is provided.

The base portion 8c is formed with a hole 8f into which the key portion 5a is inserted when the straight key ring 5 is assembled, the above-mentioned flexible guide portion 8g, and four screw holes 8h.

When attaching the straight key ring 5 to the cam cylinder 2, first, as shown in FIG.
b into the guide groove 2b of the cam cylinder 2 and then the small projection 8a
Into the guide groove 2b through the opening groove 2c. In addition,
In this rotation phase, the coupling member 8 comes off the cam cylinder 2, but does not come off in other rotation phases. For this, a conditional expression () is required. Further, when the conditional expression () is satisfied, there is some play in the radial direction between the cam cylinder 2 and the coupling member 8, so that it is easy to assemble.

After the connecting member 8 is held by the cam cylinder 2 in this manner, the straight key ring 5 is screwed to the connecting member 8 with the screw 7 as shown in FIG. Since the number of the connecting members 8 is one and they do not come off from the cam cylinder 2 in the screwing direction, the screwing holes 5d of the straight key ring 5 and the screwing holes 8h of the connecting member 8 can be easily aligned. can do. Therefore, the screwing workability is improved as compared with the conventional one. Further, for the above-described reason, since a force in the axial direction may be applied to the coupling member 8, a self-tap assembling that can eliminate the need for the tapping of the coupling member 8 in advance may be performed.

Further, when the straight key ring 5 is attached to the coupling member 8, the base 5c of the straight key ring 5 is radially fitted to the edge 2d of the cam cylinder 2 (conditional expression ()). The coupling member 8, which had a play before mounting, is also accurately held with respect to the optical axis. Therefore, it is easy to align the optical axes of the front cylinder 3 and the cam cylinder 2 guided by the straight key ring 5 and the rear cylinder 4 guided by the front cylinder 3.

In this embodiment, when the phase of the small projection 8a of the coupling member 8 and the opening groove 2c of the cam cylinder 2 match, the coupling member 8 comes off the cam cylinder 2, but this phase is 360 degrees. This is a very small part of the phase, and a configuration in which the lens barrel is extended while avoiding this phase does not limit the degree of freedom in design.

The above embodiment is an example of a lens barrel to which the present invention is applied. In the present invention, a cylindrical lens barrel constituting member, a guide member, and this guide member are attached to the lens barrel constituting member. To all lens barrels having a coupling member for the

[0046]

As described above, according to the present invention,
At the time of assembling the lens barrel, first, the connecting member is held by the lens barrel constituent member in a state where movement of the lens barrel constituent member is restricted at least in the axial direction. Can be easily installed. Therefore, it is possible to realize a lens barrel which is easy to assemble and can be manufactured at low cost.

If the guide member is fitted to the inner diameter of the lens barrel constituting member to restrict the radial movement of the guide member, light from the guide member and the lens holding member guided by the guide member can be controlled. Axis alignment can be performed easily.

Further, if a diaphragm opening is formed in the coupling member, occurrence of flare and the like can be prevented without providing a separate diaphragm member.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing main components of a zoom lens barrel according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a cam barrel, a coupling member, and a straight key ring of the zoom lens barrel.

FIG. 3 is an exploded perspective view of the coupling member and the straight key ring.

FIG. 4 is a sectional view showing an assembled state of the cam cylinder, the coupling member, and the straight key ring.

FIG. 5 is an explanatory diagram of dimensions of the cam cylinder.

FIG. 6 is a dimensional explanatory view of the coupling member.

FIG. 7 is an explanatory diagram of dimensions of the straight key ring.

FIG. 8 is an explanatory view of assembling a coupling member to the cam cylinder.

FIG. 9 is an exploded perspective view of a conventional zoom lens barrel.

FIG. 10 is a sectional view showing an assembled state of a conventional zoom lens barrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 101 Fixed cylinder 2, 102 Cam cylinder 2b, 102b Guide groove 2c Open groove 2d Edge 3,103 Front group cylinder 4,104 Rear group cylinder 5,105 Straight key ring 5a, 105a Key part 5b, 105b Guide part 5c Base 5d screw hole 8 coupling member 8a small projection 8b large projection 8c base 8d aperture hole 8g flexible guide section 8h screw stop hole 106 aperture plate 108 holding member

Claims (7)

[Claims] 1. A cylindrical lens barrel constituent member, a guide member for guiding another lens barrel structural member disposed inside the lens barrel structural member in an axial direction, and an inner diameter portion of the lens barrel structural member A disk-shaped coupling member attached to the guide member and integrally connected to the guide member; a first projection having an outer diameter portion and a circumferential width larger than the first projection on the outer diameter portion of the coupling member; Two projections, extending in the circumferential direction on the inner diameter portion of the lens barrel constituting member,
And a fitting groove for fitting the second protrusion, and a groove opened at an axial end face of the inner diameter portion and connected to the fitting groove, and having a width equal to or larger than the width of the first protrusion and smaller than the width of the second protrusion. A lens barrel, wherein an opening groove having a width is formed. 2. The lens barrel according to claim 1, wherein the guide member is fitted into the inner diameter portion of the lens barrel constituting member so as to restrict the radial movement of the guide member. 3. The lens barrel according to claim 1, wherein the coupling member is guided in a rotational direction by fitting the first and second protrusions and the fitting groove. 4. The lens barrel according to claim 1, wherein a stop aperture is formed in the coupling member. 5. A fixed cylinder fixed to the camera body, and a cam or a helicoid screw part which can rotate at least with respect to the fixed cylinder and axially drives a lens holding member disposed inside. A cylinder, a coupling member rotatably attached to the cam cylinder, and a guide member axially guiding the lens holding member integrally coupled to the coupling member and driven by rotation of the cam cylinder. The coupling member is formed in a disk shape, and a first projection and a second projection having a width in a circumferential direction larger than the first projection are formed on an outer diameter portion of the coupling member. A fitting groove extending in the circumferential direction for fitting the first and second protrusions movably in a rotational direction to the inner diameter portion of the cam cylinder; As well as the groove Serial first lens barrel, characterized in that to form the open groove having a smaller groove width than a width of the second protrusion at least the width of the protrusion. 6. The lens barrel according to claim 4, wherein the guide member is fitted to the inner diameter portion of the cam barrel so as to restrict the radial movement of the guide member. 7. The lens barrel according to claim 5, wherein a stop aperture is formed in the coupling member.