JP2003074579A - Rotary driving force transmission mechanism and exchange lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability of a rotary drive force transmission mechanism. SOLUTION: The mechanism is provided with a supply member 4 supplying a rotary drive force, a member 5 to be supplied to which the drive force is supplied by engagement with the supply member 4, and it has either a structure that the corner of a lower bending elastic modulus member gets into contact with a higher bending elastic modulus member face or a structure that the face of the lower bending elastic modulus member gets into contact with the face of the higher bending elastic modulus member. In the second claim of the application, the supply member 4 is a tabular item and the member 5 to be supplied is a contact part. When the width of the tabular member is a, the width of the contact part is C, and the angle between the face of the tabular member and the face of the contact part is b, an expression, 0<C/2<(a/2)×cos(b), is characterized. The third claim of the application is featured in that the angle formed in the contact position of the tabular member and the contact part in the second claim is equal to the angle b formed by the face of the tabular member and the face of the contact part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary driving force transmission mechanism used in cameras, video cameras and the like.

[0002]

2. Description of the Related Art Due to the nature of cameras and video cameras,
It is necessary to drive the lens and feed the film and tape during shooting. To achieve this mechanism, a motor is used as its drive source. The rotational force of the motor is obtained as an appropriate rotational force by the driving unit such as the lens at the final end via the transmission system. In order to achieve this, many gears (reduction mechanism) are used between the motor and the lens driving unit. Normally, when a lens or the like is driven, all the parts of the drive mechanism, specifically, the meshing parts of the gears, the sliding parts such as the shaft, the motor main body, and the like, produce an abnormal noise that is sensationally annoying.

As an example of such a transmission system, there is a coupling portion as a mechanism for transmitting a rotational force from the body side to the lens side. The structure (mechanism) is a system in which there is a slit-shaped groove at the tip of the lens side shaft component, and the tip of the body side shaft component meshes with the groove to transmit the rotational force. A part of the lens side component has a gear shape, and this part further meshes with the gear on the lens side. Since the transmission torque is very high in this portion, conventionally, a metal-based material (SUS or the like) has been frequently used. As a result, more offensive sounds were produced than with other mechanisms. In addition, the cost is very high because a metal material is used.

[0004]

Therefore, it is considered to make the gear of the coupling ring plastic. If this becomes possible, the problems such as the above-mentioned noise will be solved, but if a plastic is used, the durability will naturally deteriorate.
In particular, accidents that damage the sleeve part are likely to occur. The cause is the corner portion 100a of the body side coupling gear P.
And 100b (FIG. 4) collide with the i-side surface and the j-side surface (FIG. 4) which are the wall surfaces of the lens-side coupling ring Q, and a crack is generated on the wall surface of the lens-side coupling ring Q, and the cracks are left as they are. It progresses and leads to damage.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the durability performance of a rotary drive force transmission mechanism.

[0006]

To achieve this object, the invention of claim 1 provides a supply member (4) for supplying a rotational drive force and a rotational drive force by engagement from the supply member (4). The supply target member (5) to be supplied is provided, and a corner portion of the supply member (4) and the supply target member (5) having a lower bending elastic modulus is in contact with a surface portion having a higher bending elastic modulus. It is characterized in that they are in contact with each other, or a surface portion having a lower bending elastic modulus and a surface portion having a higher bending elastic modulus are in contact with each other.

According to a second aspect of the present invention, the supply member (4) is a plate-shaped member and the supply target member (5) is an abutting portion, and the width a of the plate-shaped member, the width C of the abutting portion, the plate. When the angle b formed by the surface of the member and the surface of the contact portion is

[0008] 0 <C / 2 <(a / 2) x cos (b) Is characterized in that.

According to a third aspect of the invention, in the second aspect, the angle formed by the plate member and the contact portion at the contact portion is
It is characterized in that it is substantially equal to the angle b formed by the surface of the plate member and the surface of the contact portion.

The invention of claim 4 is the invention of claims 2 to 3.
In, the radial length of the contact surface is smaller than C / 2.

The invention of claim 5 is the invention of claims 1 to 4.
In, the supply member (4) and the supplied member (5) are separable, the supply member (4) is provided on the body side of the single-lens reflex camera, and the supplied member (5) is the single-lens reflex camera. It is characterized in that it is provided on the lens side.

In the invention of the interchangeable lens of claim 6, there is provided a member to be supplied (5) which is engaged with the supply member (4) for supplying the rotational driving force and is supplied with the rotational driving force. 5)
Is made of a material having a low flexural modulus, and has corners (h, g) for receiving the supply member (4).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are a top view and a vertical sectional view showing an embodiment of a rotary driving force transmission mechanism according to the present invention.

In FIG. 1, an interchangeable lens 1 is attached to a camera body 2 with a lens mount 1a and a body mount 2a engaged with each other. A motor 3 for generating a rotational driving force is built in the camera body 2, and the generated rotational driving is transmitted to the body side coupling 4.

The body side coupling 4 engages with the lens side coupling 5 at its tip (lower side in FIG. 1) (see FIG. 2). A coupling gear 5b is provided at a tip portion (lower side in FIG. 1) of the lens-side coupling 5, and the coupling gear 5b meshes with the gear 6.

As shown in FIG. 2, a plate-shaped thin portion 4a is formed integrally with the body-side coupling 4 at the tip portion (lower side in FIG. 2) of the body-side coupling 4. In addition, a slit-like groove 5a is formed integrally with the lens-side coupling 5 at the tip (upper side in FIG. 2) of the lens-side coupling 5.

When the interchangeable lens 1 is attached to the body mount 2a, the thin portion 4a is brought into the state shown in FIG. 2 in which the thin portion 4a is engaged with the groove portion 5a. When the motor 3 generates the rotational driving force in this state, the driving force is generated by the body side coupling 4 and the thin portion 4
It is transmitted to the gear 6 via a, the groove portion 5a, the lens side coupling 5 and the coupling gear 5b.

The body side coupling 4 and / or the lens side coupling 5 are made of PP instead of the current metal material.
S (polyphenylene sulfide), PI (polyimide), LCP (liquid crystal polymer) materials are used. As a matter of course, the same applies to the thin portion 4a and / or the groove portion 5a formed integrally.

As a result, for example, in PPS, the rotation durability of the gear 5b was lowered, but 50,000 rotations were achieved and the standard was cleared. Moreover, as a further effect, the driving sound is reduced by 3 dB,
The cost was also reduced to 3/10 of the current metal parts.

Any of polyamide, polyether sulfone, ethylene / vinyl alcohol copolymer, polyethylene naphthalate, polybutylene terephthalate, and polyether ether ketone is effective although there are some differences.

PC (polycarbonate), PA
(Polyamide), POM (Polyacetal) material GF
(Glass fiber) or CF (carbon fiber)
Even if the reinforcing fiber is not added, a great effect can be obtained only by reducing the sound and reducing the cost. This is shown in Table 1,
They are collectively described as "execution 1".

[Table 1]

In Example 2 of Table 1, PA (polyamide) material was used instead of the material of Example 1, and GF was used.
Alternatively, it is an example in which a reinforcing fiber such as CF is added. Also,
In Example 3 of Table 1, a PA material (addition of GF, CF, etc.) is used in place of the material of Example 1, and sliding noise is generated on the contact surface with the body side coupling 4, that is, the groove 5a. This is an example in which a surface treatment is performed in order to reduce wear and improve wear resistance.

FIG. 3 is a transverse sectional view showing a first embodiment of the rotary driving force transmission mechanism according to the present invention.

In FIG. 3, the width a of the thin portion 4a and the groove 5
When the width C of a is the angle b formed by the surface of the thin portion 4a and the surface of the groove portion 5a,

It is set as 0 <C / 2 <(a / 2) × cos (b). In other words, the lens side coupling 5
The corners h and g of the body-side coupling 4 (thin portion 4a) that receives the (groove 5a) are the lens-side coupling 5
It is configured to be located on the outer side in the radial direction of the (groove portion 5a). With such a structure, the durability performance has been improved from 10,000 times in the past (currently) to 20,000 times (Example 1 in Table 2).

[Table 2]

Further, the lengths of the portions where the thin portion 4a and the groove portion 5a collide, that is, the e portion and the f portion are set within the following ranges.
With this setting, the durability performance was further improved to 25,000 times (Example 1 in Table 2).

0 <length of e, f <C / 2

In the second embodiment, in addition to the requirements of the first embodiment, the radial length of the contact surface between the thin portion 4a and the groove portion 5a is smaller than C / 2, ideally 1 / It is about 5. As a result, the durability performance was improved to 30,000 times (Example 2 in Table 2).

[0030]

As described above, according to the rotational driving force transmission mechanism of the present invention, the corner of the supply member (4) and the supply target member (5) having the lower bending elastic modulus is bent elastically. Since the surface portion having the higher bending modulus or the surface portion having the lower bending elastic modulus and the surface portion having the higher bending elastic modulus are in contact with each other, the durability of the rotary drive force transmission mechanism is improved. It becomes possible.

[Brief description of drawings]

FIG. 1 is a top view showing an embodiment of a rotary driving force transmission mechanism according to the present invention.

FIG. 2 is a vertical cross-sectional view showing an embodiment of a rotary drive force transmission mechanism according to the present invention.

FIG. 3 is a cross-sectional view showing a second embodiment of the rotary drive force transmission mechanism according to the present invention.

FIG. 4 is a cross-sectional view showing an example of a conventional rotary drive force transmission mechanism.

[Explanation of symbols]

1 interchangeable lens 1a lens mount 2 camera body 2a body mount 3 motor 4 Body side coupling 4a Thin part 5 Lens side coupling 5a groove 5b coupling gear 6 Coupling gear

Claims (6)

[Claims] 1. A supply member that supplies a rotational driving force, and a supply target member that is supplied with the rotational driving force by engagement from the supply member, wherein bending of the supply member and the supply target member is performed. The corner with the lower elastic modulus contacts the surface with the higher flexural modulus, or the surface with the lower flexural modulus and the surface with the higher flexural modulus contact each other. A characteristic rotary drive force transmission mechanism. 2. The supply member is a plate member, the supply target member is an abutting portion, the width a of the plate member, the width C of the abutting portion, the surface of the plate member and the A rotational driving force transmission mechanism, wherein 0 <C / 2 <(a / 2) × cos (b) at an angle b formed by the surface of the contact portion. 3. The angle formed by the plate-shaped member and the contact portion at the contact portion is substantially equal to the angle b formed by the surface of the plate-shaped member and the surface of the contact portion. The rotation drive force transmission mechanism according to claim 2. 4. The rotary drive force transmission mechanism according to claim 2, wherein the radial length of the contact surface is smaller than C / 2. 5. The supply member and the supply target member can be separated from each other, the supply member is provided on the body side of the single lens reflex camera, and the supply target member is provided on the lens side of the single lens reflex camera. The rotary drive force transmission mechanism according to claim 1, wherein 6. Engaging with a supply member for supplying rotational driving force,
An interchangeable lens comprising: a driven member supplied with a rotational driving force, the driven member being made of a material having a low bending elastic modulus, and having a corner portion for receiving the supply member.