JPH0743584A - Structure of lens barrel for camera - Google Patents

Abstract

PURPOSE:To make cost low and to reduce assembly man-hour by decreasing the number of parts. CONSTITUTION:In a camera provided with a differential barrel 3 which is turnably held on the inner peripheral surface of a fixed barrel 2 and whose position in an optical axis direction is regulated by its rotational phase, a straight advance guide 4 which is regulated corresponding to the position of the barrel 3 and whose rotational phase is regulated by the fixed barrel 2, a driving pin 5 which is positioned at the outer peripheral part of the fixed barrel 2 and fixed on the barrel 3, and a driving ring 1 applying force in a rotating direction to the pin 5; a projection 5a engaged in a groove part in a circumferential direction provided in the guide 4, turnably holding the guide 4 with respect to the barrel 3 and preventing slip-off is provided at the tip of the pin 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel structure for a camera.

[0002]

2. Description of the Related Art FIG. 3 is a partial cross-sectional view showing a conventional lens barrel structure of a camera, in which 101 is a drive ring, and 102 is a fixed barrel fitted to the outer peripheral surface of the drive ring 101 and fixed to the camera body. , 103 are differential cylinders that are located on the inner peripheral portion of the fixed cylinder 102 and are extended while rotating with respect to the fixed cylinder. 104 is a key groove provided in the fixed barrel 102 that is integrally extended with the differential cylinder 103. A linear guide 105, whose rotation direction is restricted by engagement of an engaging projection (not shown),
Is a drive pin that is screwed to the differential cylinder 103, engages with a cam groove portion 102a provided on the fixed cylinder 102, and further has its tip engaged with a rectilinear groove portion 101a of the drive ring 101.

Each lens group holding member (not shown) includes a rectilinear groove portion (not shown) of the rectilinear guide 104 and the differential barrel 1.
The position of the drive pin 101 is regulated by a cam groove (not shown) formed on the inner peripheral portion of the drive pin 03, and the drive pin 10 is driven by driving the drive ring 101 by a drive means (not shown).
5 is extended along the cam groove 102a of the fixed barrel 102, and as a result, the differential barrel 103 is extended while rotating.

At this time, the rectilinear guide 104 is fixed to the drive pin 105, and one end thereof is extended together with the differential cylinder 103 by the action of the retaining member 106 having an L-shape. Is engaged with the linear guide key groove of the fixed barrel 102, so that it is fed out integrally with the differential barrel 103 without rotating. By the relative rotation of the differential barrel 103 and the rectilinear guide 104, each lens group holding member is further extended in the differential barrel, and so-called differential zoom is performed.

In FIG. 4, a flange portion 104a is provided on the straight guide 104, and a straight guide retaining member 106 is attached to a screw hole 104c provided in the flange portion 104a.
It is fixed at 7.

FIG. 5 is a partial sectional view showing another conventional example,
FIG. 6 is an exploded perspective view thereof.

5 and 6 in which the same parts as those in FIG.
Reference numeral 04 is located on the inner peripheral portion of the first lens group holding member 107, and the key groove portion 107a of the first lens group holding member 107 and the protrusion 104a of the rectilinear guide 104 are key-connected to each other, so that the rotation of the first lens group holding member 107 is restricted. Has been done.

Similarly, two lens group holding members 111 and 3
The lens group holding member 112 also has the respective key groove portions 111.
a and 112a are projections 104a of the straight guide 104
The key is connected with and the rotation is restricted.

Numeral 108 is a decorative plate attached to the front end of the one lens group holding member 107, 109 is a holder for the one lens group 110, and 113, 114 and 115 are the one lens group holding member 10.
7, 2 lens group holding member 111, 3 lens group holding member 1
12 are projections formed on each of the projections 113, 11
Reference numerals 4 and 115 are engaged with recesses formed on the inner surface of the differential cylinder 103.

[0010]

However, in the above conventional example, (1) the retaining member 106 fixed to the drive pin 105.
Therefore, there is a problem that the number of parts and the number of assembling steps increase.

(2) In particular, in the conventional example shown in FIGS. 5 and 6, (a) the first lens group holding member 107 has a notched key groove 107a on the inner peripheral surface thereof, and the second and third lens group holding members 11 are formed.
Notch-shaped key grooves 111a, 11 on the outer periphery of 1, 112
Since 2a is required, the space cannot be used effectively.

(B) The straight guide 104 is not connected at its tip end in a ring shape. Therefore, in order to regulate the rotation of each lens group at the tip portion, it is necessary to increase the thickness of the root portion 104b, which is disadvantageous in space. Further, since the tip portion thereof is not connected in a ring shape, there is a problem that it is difficult to obtain dimensional accuracy of parts.

(3) Cam groove 1 formed in the fixed barrel 102
No. 02a has a so-called mold splitting portion in the middle of the cam groove in order to avoid an undercut due to the mold structure when molding is performed, and a step is formed in that portion, so that the optical position cannot be guaranteed at that position. Therefore, it is necessary to post-process the cam groove, which causes a problem that the parts become expensive.

(4) In order to solve the above-mentioned problem (2), as shown in FIG. 7, the linear guide 104 is connected to the first lens group holding member 107, the second lens group holding member 111 and the third lens group holding member 112. Pins 116, 1 located on the outer periphery
17, 118 are straight groove portions 10 of the straight guide 104.
4a and cam groove portions 103a, 103b of the differential cylinder 103,
When it is configured to be engaged with 103c and define its position, the following problems occur.

When the front end of the first lens group holding member 107 hits a desk or the like while the camera is being carried, the impact force is received by the pin 116 and the cam groove portion 103a. At this time, the screw-fastening portion 10 that fastens the portion that receives this impact force and the pin 116 to the first lens group holding member 107 by screws.
In 7a, since the thickness of the straight guide 104 is separated, in addition to impact force, moment force is applied to the screw portion,
There is a problem in strength if the first lens group holding member 107 is joined only by the thick portion.

Further, in order to solve this problem, a nut is arranged on the inner peripheral portion of the first lens group holding member 107, and the pin 1
If the structure in which the first lens group holding member 107 is sandwiched by 16 and a nut (not shown) is added, the number of parts and costs are increased, and further, a notch portion for escaping the nut portion is two.
Since it is necessary for the lens group holding member 111, the above (2)
As described above, there is a problem in space efficiency.

An object of the present invention is to obtain a lens barrel structure for a camera that solves the above problems.

[0018]

According to the first aspect of the present invention, there is provided a fixed barrel that holds the taking lens optical system and is fixed to the camera body, and is rotatably held on the inner peripheral surface of the fixed barrel. At the same time, a differential cylinder whose position in the optical axis direction is defined by its rotation phase, and a position in the optical axis direction that is located on the inner peripheral side of the differential cylinder and is defined corresponding to the position of the differential cylinder. Along with that, a linear guide whose rotation phase is defined by the fixed barrel, a drive pin which is located on the outer peripheral portion of the fixed barrel and which is fixed to the differential barrel, and a drive ring which applies a rotational force to the drive pin. In the camera having the above-mentioned, the projection of the tip of the drive pin is engaged with a groove in the circumferential direction provided in the straight-moving guide to rotatably hold the straight-moving guide with respect to the differential cylinder and to prevent the same from coming off. Cost reduction and assembly Reduction of man-hours is possible.

According to the second aspect of the present invention, the fixed barrel which holds the taking lens optical system and is fixed to the camera body, and the rotatable barrel is rotatably held on the inner peripheral surface of the fixed barrel. A differential barrel whose position in the optical axis direction is defined, and a position which is located on the inner peripheral side of the differential barrel and whose optical axis direction is defined in correspondence with the position of the differential barrel, and whose rotational phase is fixed A straight guide defined by a cylinder, rotation restricted by the straight guide, and an optical position thereof defined by a cam groove formed in the differential cylinder.
In a camera having two lens group holding members, the rectilinear guide has a rectilinear groove part for restricting rotation of the lens group holding member, and a key part for restricting rotation of the rectilinear guide itself is formed in the same phase as the rectilinear groove part. As a result, it is possible to improve space efficiency, improve part accuracy, and improve productivity.

According to the third aspect of the present invention, the fixed barrel that holds the optical system of the photographing lens and is fixed to the camera body, the inner barrel of the fixed barrel is rotatably held, and the rotation phase thereof causes A differential cylinder whose optical axis direction position is defined, and a position which is located on the inner peripheral side of this differential cylinder and whose optical axis direction position is defined corresponding to the position of the differential cylinder, and whose rotational phase is fixed. A camera having a straight guide defined by a cylinder, a drive pin fixed to the differential cylinder at an outer peripheral portion of the fixed cylinder, and a drive ring applying a rotational force to the drive pin, The fixed barrel and the differential barrel are helicoidally coupled with each other, and the fixed barrel has a groove portion through which the drive pin penetrates, and the groove portion is formed so as not to fit with the drive pin, so that the impact resistance is improved. Can realize an excellent camera

According to the fourth aspect of the present invention, the fixed barrel which holds the taking lens optical system and is fixed to the camera body, and the rotatable barrel is rotatably held on the inner peripheral surface of the fixed barrel. A differential barrel whose position in the optical axis direction is defined, and a position which is located on the inner peripheral side of the differential barrel and whose optical axis direction is defined in correspondence with the position of the differential barrel, and whose rotational phase is fixed An optical position is defined by a pin formed on the outer periphery of a straight guide defined by a cylinder, a straight groove formed on the straight guide, and a cam groove formed on the differential cylinder. In the camera having at least two lens group holding members, the pin is formed integrally with the lens group holding member up to at least a portion that engages with the straight guide, so that the pin has excellent impact resistance. ,
It is possible to realize a camera that is advantageous in terms of space.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of the essential parts showing an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof.

In FIGS. 1 and 2, reference numeral 1 denotes a drive ring which is rotated by being given a force from a drive source (not shown) through a known power transmission means (not shown).
The rectilinear groove portions 1a, 1b, 1c provided in the above are engaged with the drive pin 5 to be described later and give a rotational force. Reference numeral 2 denotes a fixed cylinder fixed to a camera body (not shown), and the drive ring 1 is rotatably fitted and held on the outer peripheral surface of the fixed cylinder 2 and three female helicoids 2a are formed.

Reference numeral 3 denotes a differential cylinder fitted inside the fixed cylinder 2. This differential cylinder 3 has a female helicoid 2 corresponding to three male helicoids 3a formed on the outer surface of the end.
It is helicoid-bonded with a. Further, a groove portion 2b through which the drive pin 5 penetrates is formed in the fixed cylinder 2, the drive pin 5 penetrates the groove portion, and a tip portion thereof is fitted into a straight groove portion 1a of the drive ring 1.

Reference numeral 4 is a linear guide which is rotatably fitted and held in the inner peripheral portion of the differential cylinder 3. Reference numeral 5 denotes a drive pin that penetrates through the straight groove portion 1a of the drive ring 1 and the groove portion 2b of the fixed barrel 2 and is screwed into the screw hole 3b of the differential barrel 3, and the screw tip of the drive pin 5 that penetrates the screw hole 3b. 5a formed on the bottom part
Engage with three circumferential grooves 4a formed in the vicinity of the rear end of the straight guide 4.

Therefore, the straight-ahead guide 4 is extended in association with the differential barrel 3. At this time, three protrusions 4c formed at the rear end in the same phase as the straight-moving groove 4b of the straight-moving guide 4 are engaged with the straight-moving groove portion 2c formed in the inner peripheral portion of the fixed barrel 2. It moves in the optical axis direction in conjunction with the differential barrel 3 without rotating.

Reference numeral 6 denotes a 1-lens group holding member for holding a 1-lens group (not shown). At the substantially rear end portion of the 1-lens group holding member 6, there are three pieces which engage with the straight-moving groove portion 4b of the straight-moving guide 4. A cylindrical projection 6a is formed, and a pin 7 that engages with a known cam groove (not shown) formed on the inner peripheral portion of the differential cylinder 3 is fitted into the tip of the cylindrical projection 6a. .

Reference numeral 8 denotes a two-lens group holding member equipped with a known shutter driving unit and a lens driving unit for focusing on an object. Similar to the lens group holding member 6, a substantially cylindrical protrusion 8a that engages with the rectilinear groove 4b of the rectilinear guide 4 and a pin 8b that engages with a cam groove (not shown) formed on the inner peripheral portion of the differential cylinder 3 are integrally formed. Has been formed.

Reference numeral 9 denotes a third lens group holding member for holding the third lens group, and a substantially cylindrical projection 9a and a pin 9b, which are similar to those of the second lens group holding member 8, are integrally formed on the outer peripheral portion of the three lens group holding member. Has been done.

Then, the above-mentioned one lens group holding members 6, 2
The respective substantially cylindrical protrusions and pins of the lens group holding members 8 and 3 lens group holding members 9 are incorporated from behind so as to pass through the inner diameter cutout portion 4d of the projection portion 4c of the straight guide 4. At this time, the cam groove (not shown) formed on the inner peripheral surface of the differential barrel 3 is pulled out to the rear end portion in the optical axis direction so that the lens group holding members can be assembled from the back side. The phase in which each lens group holding member is incorporated is outside the zoom area of the camera.

Next, the zooming operation of the zoom lens barrel having the configuration of the above embodiment will be described.

When the drive ring 1 is rotated by receiving a driving force from a drive source (not shown), the drive pin 5 engaged with the rectilinear groove portion 1a is rotated and the differential cylinder 3 is rotated at the same time. Since the male helicoid portion 3a of the differential barrel 3 and the female helicoid portion 2a of the fixed barrel 2 are helicoid-coupled, the differential barrel 3 is extended along the helicoid with respect to the fixed barrel 2.

At this time, the straight guide 4 is extended in conjunction with the differential cylinder 3 because the screw tip portion 5a of the drive pin 5 is engaged with the circumferential groove portion 4a. The differential barrel 3 is fed out while rotating with respect to the fixed barrel 2, but the straight guide 4 has the protrusion 4c engaged with the straight groove 2e formed in the inner peripheral portion of the fixed barrel 2, so that the fixed barrel is fixed. It will be paid out without rotating with respect to 2.

As a result, the differential barrel 3 and the straight guide 4 rotate relatively. Each lens group holding member 6,
8 and 9 have their cylindrical protrusions 6a, 8a and 9a engaged with the rectilinear groove 4b of the rectilinear guide 4 to restrict their rotation,
Further, the pins 7, 8b, 9b are engaged with a cam groove (not shown) formed on the inner peripheral surface of the differential cylinder 3, whereby the position in the optical axis direction is defined.

Therefore, by the relative rotation of the linear guide 4 and the differential barrel 3, each lens group moves in the optical axis direction along the locus of the cam groove formed in the differential barrel 3. At this time, the amount of movement of each lens group is the sum of the amount of extension of the differential barrel 3, and the cam groove on the inner peripheral surface of the differential barrel is adjusted so that this amount matches the amount determined by optical design. Has been formed. With the above operation, each lens group performs a predetermined zoom operation.

In the above embodiment, the pins 7, 8b, 9b provided on the respective lens group holding members 6, 8, 9 are tapered conical rollers, but these are cylindrical like the drive pin 5. Rollers or other shapes may be used.

In the above embodiment, the substantially cylindrical projections 6a and 8 formed on the lens group holding members 6, 8 and 9 are used.
The shapes of a and 9a may be a quadrangular prism shape or other shapes as long as they can be engaged with the rectilinear groove 4b of the rectilinear guide 4.

[0038]

As described above, according to the first aspect of the present invention, the screw tip of the drive pin is provided with the protrusion that engages with the circumferential groove of the linear guide to prevent the linear guide from coming off. With this configuration, it is possible to reduce the number of parts, reduce costs, and reduce the number of assembly steps.

According to the second aspect of the present invention, the rectilinear groove of the rectilinear guide is formed up to the rear end so that each lens group holding member can be incorporated from the back side, and the rectilinear guide itself rotates at the substantially rear end of the rectilinear guide. Since a key-shaped protrusion that regulates the movement is formed and it is possible to connect the meat to the straight groove by this protrusion, it is possible to improve space efficiency, improve part accuracy, and improve productivity. .

According to the third aspect of the present invention, the fixed barrel and the differential barrel are helicoidally coupled to each other, and the fixed barrel is formed with the escape groove which is coincident with the helicoid lead and through which the drive pin penetrates. Therefore, the component is molded. Therefore, the problem of the mold structure is solved and the optical performance is improved. Also, when carrying the camera, if the helicoid comes off due to the impact force when the tip of the lens barrel of the camera hits a desk etc., the drive pin will contact the escape groove of the fixed barrel and absorb the impact force. A camera with excellent impact resistance can be realized, and even if a dent due to the drive pin remains in the escape groove due to the impact force, there is no problem in optical performance.

According to the invention of claim 4, since the pin formed on the outer peripheral portion of the lens holding member is engaged with the rectilinear groove formed in the rectilinear guide, impact resistance is achieved as in the above case. It is excellent and does not require a nut to increase strength, which is advantageous in terms of space.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a lens barrel structure of a camera embodying the present invention.

FIG. 2 is an exploded perspective view of a main part thereof.

FIG. 3 is a partial sectional view showing a lens barrel structure of a conventional camera.

FIG. 4 is a sectional view in which a part of FIG. 3 is modified.

FIG. 5 is a partial sectional view showing another lens barrel structure of a conventional camera.

6 is an exploded perspective view of FIG.

FIG. 7 is a partial sectional view showing still another lens barrel structure of a conventional camera.

[Explanation of symbols]

 1 Drive Ring 2 Fixed Cylinder 3 Differential Cylinder 4 Straight Guide 5 Drive Pin 6 1 Lens Group Holding Member 7, 8b, 9b Pin 8 2 Lens Group Holding Member 9 3 Lens Group Holding Member

Claims (4)

[Claims] 1. A fixed barrel that holds a taking lens optical system and is fixed to a camera body, and a fixed barrel that is rotatably held on an inner peripheral surface of the fixed barrel and defines its position in the optical axis direction by the rotation phase. And a linear guide which is located on the inner peripheral side of the differential cylinder and whose optical axis direction position is defined in correspondence with the position of the differential cylinder and whose rotational phase is defined by the fixed cylinder. In a camera having a drive pin located on an outer peripheral portion of the fixed barrel and fixed to the differential barrel, and a drive ring that applies a force in a rotational direction to the drive pin, a circle provided on the straight guide. A lens barrel structure for a camera, characterized in that a projection is provided at the tip of the drive pin to engage with a groove in the circumferential direction to rotatably hold the straight guide with respect to the differential barrel and to prevent it from coming off. . 2. A fixed barrel which holds an optical system of a photographing lens and is fixed to a camera body, and a rotatably held on an inner peripheral surface of the fixed barrel, and its rotational phase defines the position in the optical axis direction. And a linear guide which is located on the inner peripheral side of the differential cylinder and whose optical axis direction position is defined in correspondence with the position of the differential cylinder and whose rotational phase is defined by the fixed cylinder. And at least two lens group holding members whose rotation is regulated by the straight guide and whose optical position is defined by a cam groove formed in the differential barrel, wherein the straight guide is the lens group. A lens barrel structure for a camera, comprising: a straight groove portion for restricting rotation of a holding member, and a key portion for restricting rotation of the straight guide itself formed in the same phase as the straight groove portion. 3. A fixed barrel which holds a taking lens optical system and is fixed to a camera body, and a fixed barrel which is rotatably held on an inner peripheral surface of the fixed barrel and defines its position in the optical axis direction by its rotation phase. And a linear guide which is located on the inner peripheral side of the differential cylinder and whose optical axis direction position is defined in correspondence with the position of the differential cylinder and whose rotational phase is defined by the fixed cylinder. In a camera having a drive pin fixed to the differential barrel and located on an outer peripheral portion of the fixed barrel, and a drive ring for applying a rotational force to the drive pin, the fixed barrel and the differential barrel are A lens barrel structure for a camera, which is helicoidally coupled and has a groove portion through which the drive pin penetrates, the groove portion being formed so as not to fit with the drive pin. 4. A fixed barrel that holds a taking lens optical system and is fixed to a camera body, and a rotatably held inner peripheral surface of the fixed barrel. The rotational phase determines the position in the optical axis direction. And a linear guide which is located on the inner peripheral side of the differential cylinder and whose optical axis direction position is defined in correspondence with the position of the differential cylinder and whose rotational phase is defined by the fixed cylinder. And a straight groove formed in the straight guide,
In a camera having at least two lens group holding members whose optical position is defined by engagement of a pin formed on an outer peripheral portion of the cam groove formed on the differential barrel, the pin is at least A lens barrel structure for a camera, wherein the lens group holding member is integrally formed up to a portion that engages with a straight guide.