JPH088370Y2 - Rotational force transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is applied to, for example, a driving force transmission mechanism of a camera or the like, and a transmission member such as a gear is slidably moved along the transmission shaft to move the transmission shaft. The present invention relates to a rotational force transmission mechanism that is rotationally driven.

[Conventional technology]

In the conventional rotational force transmission mechanism of this type, the cross-sectional shape of the transmission shaft 55 is, for example, an oval shape shown in FIG.
The spline shape or the imprint serration shape shown in the figure or the key groove shape shown in FIG. 17 is generally widely applied.

[Problems to be solved by the device]

However, if the above-mentioned rotational force transmission mechanism is applied to a compact camera, various problems described below occur.

For example, the problem of the oval-shaped transmission shaft shown in FIG. 15 will be described in detail with reference to FIG.

FIG. 18 shows that a transmission member 56 such as a gear having a hole 56a having a shape similar to the sectional shape of the transmission shaft 55 is slidably fitted in the axial direction with respect to the transmission shaft 55 having an oval cross section. It shows the state. Here, the rotational force F ₁ ′ of the transmission shaft 55,
If the rotational force transmitted to the transmission member 56 is F ₂ , then F ₂ = F ₁ ′ sin ² θ. Then, assuming that the transmission member 56 transmits the rotational force while sliding the transmission shaft 55, the frictional force F ₃ ′ generated between the transmission shaft 55 and the transmission member 56 is F ₃ ′ = μF ₁ ′ sin θ = It becomes μF ₂ / sinθ (μ: friction coefficient). As a result, regarding the transmission efficiency from the transmission shaft 55 to the transmission member 56, when the rotational force F ₂ is constant, sin ² θ decreases and 1 / sin θ decreases as the frictional force.

That is, in the case of an oval-shaped transmission shaft, the transmission efficiency can be improved by reducing the thickness between two planes that are parallel to each other when viewed in cross-sectional shape, but there is a risk that the strength will decrease and deformation will occur. However, if the deformation occurs, the transmission efficiency will be further reduced.

Further, when the rotational force of the transmission shaft 55 is transmitted to the sliding transmission member 56, the frictional force between the transmission shaft 55 and the transmission member 56 becomes a problem, and the transmission efficiency further decreases.

On the other hand, in the case where the cross-sectional shape of the transmission shaft is the spline shape or the serration shape shown in FIG. 16, when trying to mold the shaft, the cross-sectional shape is complicated and the shaft cannot be removed from the mold if it is too long. Therefore, if the shaft is provided with a draft for facilitating the removal from the mold, the shaft diameter dimensions are different at both ends of the shaft, and as a result, it becomes difficult to accurately transmit the rotational force.

The present invention has been made in order to solve the above problems, and provides a rotational force transmission mechanism capable of efficiently and stably transmitting and receiving rotational force between a transmission shaft and a transmission member. With the goal.

[Means for solving the problem]

In order to achieve the above object, the present invention comprises a transmission member such as a gear and a transmission shaft that controls the transmission and reception of a rotational force between the transmission member, and either one of the transmission member and the transmission shaft or In a rotational force transmission mechanism in which both transmit and receive a rotational force while slidingly moving in the axial direction with respect to the transmission shaft, a portion distant from the shaft center of the transmission member extends divergently at a predetermined angle through the shaft center. A plurality of fan-shaped insertion holes having a pair of receiving surfaces along the radial direction line of the book are bored at equal angular intervals, and a plurality of the fan-shaped insertion holes are inserted in a portion closer to the center than the fan-shaped insertion holes. A center-side insertion hole that communicates with the hole is formed, and force transmission surfaces are formed near the outer peripheral portion of the transmission shaft along the receiving surfaces of the fan-shaped insertion hole, and the fan-shaped insertion hole. And a protrusion having a shape substantially similar to the cross-sectional shape of A thick rigid portion continuous with the protruding portion is provided at a portion closer to the center than the projecting portion, and the protruding portion is provided between the receiving surface and the receiving surface provided at a portion apart from the axial center of the transmission member. It is characterized in that the rotational force is transmitted to each other at a right angle or an angle close to a right angle with almost no rattling.

[Action]

In this invention, since the cross-sectional shape of the transmission shaft is formed with a plurality of force transmission surfaces along the line segment passing through the shaft center at least near the shaft outer peripheral portion, the rotational force of the transmission shaft or the rotational force from the transmission member is reduced. The force is transmitted from the force transmitting surface to the transmitting member at a right angle, and the transmitting mechanism having the highest transmitting efficiency can be obtained.

〔Example〕

Hereinafter, an example in which the embodiment of the present invention is applied to a double collapsible camera will be described in detail.

FIG. 1 is a partially cutaway perspective view showing the overall structure of an embodiment of a variable focus lens driving device according to the present invention.

In FIG. 1, reference numeral 1 denotes a fixed frame fixed to a fixed part (for example, a front plate) of a camera or the like; And a front plate and a rear plate provided substantially at right angles to the optical axis 3 at the film surface side (neither is shown), 1c
Reference numerals 1d and 1d denote a front window through which a front plate 1a and a rear plate 1b are punched out in a rectangular shape, respectively, and a front window through which a lens barrel frame to be described later is inserted (advancing / retreating) and a rear window through which a photographing light beam passes.

Reference numeral 2 is a third lens which is arranged in one embodiment of the rear window 1d on the optical axis 3 and is formed so that the upper and lower peripheral portions thereof are flat surfaces parallel to the optical axis 3. Reference numeral 4 denotes the lens barrel frame, which is disposed inside the fixed frame 1 and is movably supported along the optical axis 3, and 4a to 4c constitute the lens barrel frame 4. , 4a is a box-shaped lens barrel arranged so that its center coincides with the optical axis, and 4b is a plate-shaped member slightly larger than the cross section (transverse cross section) orthogonal to the optical axis 3 of this lens barrel 4a. The first lens barrel substrate 1c, which is connected to the rear end portion of the lens barrel 4a at a substantially right angle to the optical axis 3, has a small distance behind the lens barrel first substrate 4b. The lens barrel second substrate is formed almost similarly to the lens barrel first substrate 4b, and hereinafter, the lens barrel first substrate 4b and the lens barrel second substrate 4c may be collectively referred to as a lens barrel substrate 4d.

Reference numeral 5 denotes a first lens group as a first lens group disposed on the optical axis 3 on the side closest to a subject (not shown);
Reference numeral 5a denotes a cylindrical first lens frame for fixedly supporting the first lens group 5, and 6 denotes the first lens frame 5a inside the lens barrel frame 4 with the first lens frame 5a supported. The first group frames 6a, 6b and 6c supported so as to be able to move in parallel
The group frame 6 is constituted, of which 6a is a tubular portion having a rectangular shape along the optical axis 3 and having a rectangular cross section, and 6b is continuously provided at the rear end portion of the tubular portion 6a and traverses the tubular portion 6a. It is a first group substrate composed of a plate-shaped member having an area slightly larger than the surface.

The first lens group 5 (first lens frame 5a) moves integrally with the movement of the first group frame 6, while the first lens frame 5a moves.
It is configured to move independently of the first group frame 6 by a focusing mechanism (not shown) disposed on the inner wall of the lens to serve as a focusing lens.

Reference numeral 7 denotes a second lens group as a second lens group disposed behind the first lens group 5 on the optical axis 3, and 7a makes the second lens group 7 coaxial with the optical axis 3. A cylindrical second group frame 7b for fixed support is provided on the outer periphery of the second group frame 7a in a direction orthogonal to the optical axis 3, and a cam pin 7c for contacting a cam surface described later is similarly used for the second group. It is attached to the outer periphery of the frame 7a, and the second
A slider having a fork-shaped portion for preventing the rotation of the group frame 7a and guiding the movement in the optical axis 3 direction, 7d is a spring hook also planted on the outer periphery of the second group frame 7a, and 8 is the above-mentioned first A rod-shaped second group frame guide 9 fixed to the group frame 6 (specifically, the first group substrate 6b) and slidably fitted to the fork-shaped portion of the slider 7c.
Is a tubular member having openings at both ends, and the second group frame 7a is provided on the inner circumference.
With the inserted state, the outer periphery is inserted into the hollow bearing portion formed in the central portion of the first group substrate 6b, and the optical axis 3 can be rotated without moving in the optical axis 3 direction. A second group frame cam as a variable-magnification cam that is supported by the second group frame cam, 9a is a cam surface provided on the front end edge of the second group frame cam 9, and is in sliding contact with the cam pin 7b, and 9b is the second group frame cam 9. It is the second group frame cam gear fixed to the rear end portion. Tensile force is applied to 10a and 10b so that the cam pin 7b, the spring hook 7d and the first group substrate 6b are
It is a second group spring hung between the two.

11 and 12 are both arranged in the fixed frame 1, 11 is a motor as a drive unit, 12 is a reduction gear train composed of reduction gears 12a and 12b driven by a driving gear 11a of the motor 11, and 13 is substantially in the center. A drive gear having an hourglass-shaped hole 130, which is driven by the motor 11 via the reduction gear train 12, and 13a, both ends of which are fixed as described above in a state of being inserted into a bearing hole formed in the lens barrel substrate 4d. The frame 1 is rotatably supported by the front plate 1a and the rear plate 1b, and has a substantially drum-shaped cross section in which the hourglass-shaped hole 130 of the drive gear 13 is fitted and fixed to the rear end of the rear plate 1b. The first drive shaft is a transmission shaft made of a rod-shaped member parallel to the optical axis 3. 13b is sandwiched between the lens barrel first substrate 4b and the lens barrel second substrate 4c, and has a substantially drum-shaped insertion hole at the center, and the first drive shaft 13a is inserted into this insertion hole, The drive shaft 13a
Is a moving gear serving as a transmitting member, which is configured to be capable of being integrally moved with the lens barrel substrate 4d in the direction of the optical axis 3 by being transmitted with the rotational force of 1) and receiving a screw action of a drive screw described later.

Here, the shaft shape of the first drive shaft 13a and the hole shape of the moving gear 13b will be described in detail with reference to FIG.

That is, the cross-sectional shape of the first drive shaft 13a has a cutting surface 131a as a force transmitting surface along a line segment l ₁ at a predetermined angle with respect to a radial line 1 passing through the shaft center O on the side near the shaft outer peripheral portion. The protrusion 131 is provided symmetrically with respect to the center of the shaft, and the rigid portion 131b is provided at the center of the shaft so that the protrusion 131 is processed into a so-called substantially drum shape.

On the other hand, the insertion hole 132 of the moving gear 13b is formed in the first drive shaft 13
This is a hole with a similar shape that is slightly larger than the cross-sectional shape of a.
A receiving surface 132a for transmitting the rotational force of the drive shaft 13a from the cutting surface 131a in a direction perpendicular to the cutting surface 131a is formed in a part of 32.

Returning to FIG. 1 again, 14a, 14b, 14c, 15, 16a, 16b, 16
c, 17a, 17b and 17c are gears that are rotatably sandwiched between the lens barrel first substrate 4b and the lens barrel second substrate 4c, and 14a, 14b and 14c are the front sides of both end faces thereof. The gears 14a ', 14b' and 14c 'each having a small diameter are connected to the surface of the
In the multi-stage gear, 16a, 16b, 16c, 17a, 17b, 17c, female screws are screwed into holes formed in the center. 14a is a transmission gear that meshes with the moving gear 13b, and 15 is this transmission gear 14a.
Ring gears 14b and 1 serving as a transmission ring formed in a large ring shape so that the photographing light flux can pass through the central portion of the gears 14b and 1
4c is a transmission gear that meshes with the annular gear 15, 16a, 16b, 16c
Is a first group drive gear that meshes with the small diameter gears 14a ', 14b', 14c 'of the transmission gears 14a, 14b, 14c, and 17a, 17b, 17c meshes with the transmission gears 14a, 14b, 14c, respectively. It is a lens barrel drive gear.

In the following description, the transmission gears 14a, 14b, 14c are collectively referred to as the transmission gear 14, the first group drive gears 16a, 16b, 16c are collectively referred to as the first group drive gear 16, and the lens barrel drive gears 17a, 17b, 17c. The lens barrel drive gear 17 may be collectively referred to. Further, the transmission gear 14, the annular gear 15, the lens barrel drive gear 17, and the first group drive gear 16 constitute a transmission mechanism section.

Both ends 18a and 18b of the lens barrel 18 are non-rotatably supported and supported by the peripheral edges of the rear plate 1b and the front plate 1a with a slight backlash, and for example, a right-hand screw is screwed over substantially the entire length to form a lens barrel drive gear 17a. A lens barrel driving screw which is a driving means parallel to the optical axis 3 and which is screwed into the female screw of FIG. A lens barrel drive screw which is a drive means to be screwed with an internal thread, a lens barrel drive screw 20 which is also a drive means to be screwed with an internal thread of the lens barrel drive gear 17c, and the front end portions of 21, 22 and 23 are respectively first In the peripheral portion of the group substrate 6b, there is some play, although it is non-rotating, and it is supported without detaching from the first group substrate 6b. For example, a left screw is screwed over substantially the entire length to drive the first group drive. The first driving means that is substantially parallel to the optical axis screwed into the female threads of the gears 16a, 16b, 16c, respectively. A group drive screw. The lens barrel drive screws 18 to 20 and the first group drive screws 21 to 23 constitute three drive screws, respectively.

24, 25 and 26 are inserted in guide holes formed in the peripheral edge of the lens barrel substrate 4d, and are substantially parallel to the optical axis 3;
Both ends and rear end are front plate 1a and rear plate 1b, respectively.
The guide shaft is fixed to (that is, the fixed frame 1).

27 and 28 are lens barrel substrates 4d for these guide axes 25 and 26.
And a rear plate 1b, which is a lens barrel spring (a guide shaft 24 is also provided in the same manner), which is a coil spring that is provided with a compressive force.

Reference numerals 29 to 31 denote first group springs which are stretched between the first group substrate 6b and the lens barrel first substrate 4b, and are urged in a direction to approach the two.

Reference numeral 32 denotes a second transmission mechanism portion for rotationally driving the second group frame cam 9 by the rotational driving force of the annular gear 15.
It includes a reduction gear group 33a and a transmission member 33b. That is, one gear 34 meshes with the annular gear 15 and its small gear 34a
The adjusting gear 35 meshes with the small gear 35a and the second gear 36
Are in mesh. Then, the small gear 36a of the second gear 36
The third gear 37 meshes with each other to form the reduction gear group 33a.

On the other hand, the third gear 37 has a second drive shaft serving as a transmission shaft.
An input gear 38a, which is slidably supported in the optical axis direction, meshes with one end of 38, and an output gear 38b, which is axially attached to the other end of the second drive shaft 38, meshes with the second group frame cam gear 9b. It constitutes the transmission member 33b. Here, the sectional shape of the second drive shaft 38 has the same sectional shape as that of the first drive shaft 13a described above, and the input gear that slides on this shaft.
The hole shape of 38a is also the same as the insertion hole 132 of the moving gear 13b.

Although not shown, a guide shaft fixed to the lens barrel frame 4 and parallel to the plurality of optical axes 3 is inserted into, for example, a guide hole formed in the peripheral portion of the first group substrate 6b, It is configured to guide (position control) the movement of the first group frame 6 in the optical axis direction.

Further, the first lens group 5, the second lens group 7, and the third lens 2 constitute a variable focus optical system.

The state shown in FIG. 1 shows a telephoto state in which the focal length is set to the long focal length side.

One rotation of the lens barrel drive gear 17 and the first group drive gear 16 corresponds to one pitch of the lens barrel drive screws 18-20 and the first group drive screws 21-23.

In the drawings from FIG. 3 onward, the same members as those in FIG.

FIG. 3 is a schematic view of the transmission mechanism section seen from the rear side of the optical axis 3 for explaining the transmission path of the driving force (rotational force).

FIG. 4 is a vertical cross-sectional view showing a part of the first transmission mechanism portion in an enlarged manner, with the first group drive gear 16b in FIG. 1 as a representative.

In FIG. 4, 39 is a male screw portion of the first group drive screw 22,
Reference numeral 40 is a female screw portion of the first group drive gear 16b, 41 is a step portion for reducing the frictional force received from the lens barrel substrate 4d by the thrust force generated in the first group drive gear 16b, and 42 is the first group drive gear 16b.
The reference numeral 43 denotes a cylindrical shaft portion which is provided in a cylindrical shape from the center of both end surfaces of the first group drive gear 16b.

FIG. 5 is an enlarged perspective view showing in detail the configuration of both ends of the lens barrel driving screw 19 of FIG. 1 as a representative.

In FIG. 5, reference numeral 44 denotes a screw portion on which a male screw of the lens barrel driving screw 19 is screwed, reference numerals 44a and 44b denote end surfaces of the rear and front screw portions 44, and reference numerals 45a and 45b denote the end surfaces.
Oval shafts and round shafts formed integrally with 44a and 44b and formed smaller than the diameter of the threaded portion 44, 46a and 46b are similar to the shapes of the oval shafts 45a and 45b, respectively, and their outer diameters are the same. Slightly larger than the rear plate 1b and the front plate 1a
Is a support hole formed in the.

The lengths of the oval shaft 45a and the round shaft 45b are exaggerated in order to make the configuration easy to understand. Further, in the actual assembled state, the front plate 1a is in sliding contact with the end surface 44b, and the rear plate 1b
Is arranged at a position in sliding contact with the end face 44a, and the lens barrel drive screw 19
The axial position of each is precisely regulated at its end portions 19a and 19b, and it has a small degree of freedom in the circumferential direction.

FIG. 6 is an enlarged vertical cross-sectional side view showing in detail the configuration of the end portion on the side supported by the first group substrate 6b by taking the first group drive screw 22 of FIG. 1 as a representative.

In FIG. 6, 47 is a thread portion of the first group drive screw 22, 48
Is an end surface of the screw portion 47, 49 is a shaft portion formed to have a smaller diameter than the screw portion 47 from the end surface 48 to the shaft end portion, and 50 is formed in the first group substrate 6b into which the shaft portion is inserted. Further, the support hole 51 is an E-ring fitted in a circumferential groove formed in a portion of the shaft portion 49 protruding from the first group substrate 6b. Incidentally, E
The ring 51 is arranged in sliding contact with or extremely close to the first group substrate 6b, the inner diameter of the support hole 50 is slightly larger than the outer diameter of the shaft portion 49, and has a small degree of freedom in the diametrical direction. The position is regulated in the direction by the end face 48, and further, the E-ring 51 is configured to prevent the shaft portion 49 from coming off from the first group substrate 6b.

7 to 9 are longitudinal side views schematically showing three states associated with the zooming operation and the storing operation of this embodiment shown in FIG. 1, and FIG. 7 shows the first and second embodiments. FIG. 8 shows the housed state in which the lens group is driven to the housed position, FIG. 8 shows the wide state in which the focal length is set to the short focus side, and FIG. 9 shows the telescopic state described above.

In FIGS. 7 to 8, 52 is a subject located in front of the first lens group 5, and 53 is a film surface located behind the third lens 2. Reference numeral 5a denotes a first lens frame, which is not directly fixed to the first group frame 6 as described in the description of FIG. 1, but is the focusing mechanism fixed to the first group frame 6 as described above. It is supported by the first group frame 6 so that its position can be changed relative to the first group frame 6 by means of a part. Therefore, the first lens frame 5a moves integrally with the first group frame 6 while the focusing mechanism unit is not operating, and is independent of the first group frame 6 when the focusing mechanism unit operates. It is configured to be movable along the optical axis 3.

FIG. 10 to FIG. 12 both show the main configuration of the drive device for the variable focus lens. FIG. 10 is a side view schematically showing an operation relationship between the first group frame 6 and the second group frame 7a, in which FIG. 10 shows a telephoto state, FIG. 11 shows a wide state, and FIG. 12 shows a stored state. , Respectively. In these figures, the cam surface 9a and the second
In order to facilitate understanding of the correspondence with the group frame 7a, the second group frame cam 9 is shown as a reference, but actually, as described in the description of FIG. 1, the rotary motion is performed. Is the second group frame cam 9, and it is the second group frame cam 9 that moves linearly with respect to the optical axis
It is a group frame 7a.

In FIGS. 10 to 12, 54 is the optical axis 3 from the second group frame 7a.
A projecting member that extends along the rear of the fixing member 1 and is configured to have a length immediately before coming into contact with the stopper portion 1e that is a part of the fixed frame 1 in the wide state.

 The operation of this embodiment configured as described above will be described.

First, the rotational force transmission operation will be described with reference to FIGS. 1 and 3. For example, if the driving gear 11a of the motor 11 rotates clockwise as shown by the solid arrow, the drive gear 13 rotates counterclockwise via the reduction gear train 12, and this rotational force causes the drive shaft 13a to rotate. The moving gear 13b is rotated through the counterclockwise direction. The transmission gear 14a meshing with the moving gear 13b rotates clockwise, the ring gear 15 meshing therewith rotates counterclockwise, and the transmission gears 14b and 14c meshing therewith rotate clockwise. That is, the three transmission gears 14 are
All rotate clockwise. Then, the three lens barrel drive gears 17 and the three first group drive gears 16 that are respectively meshed with these transmission gears 14 all rotate counterclockwise. That is, the drive gear 11a of the motor 11 and the lens barrel drive gear 17
And it rotates in the opposite direction to the first group drive gear 16.

Now, the short focus switching operation from the telephoto state shown in FIGS. 1, 9 and 10 to the wide state shown in FIGS. 8 and 11 will be described. When the lens barrel driving gear 17 and the first group driving gear 16 rotate counterclockwise as described above, the lens barrel driving screw 18 formed of a multiple thread screwed into each female screw of the lens barrel driving gear 17 When ˜20 is a right-hand screw, the lens barrel drive screws 18-20 cannot move or rotate in the axial direction, and therefore the lens barrel drive gear 17 itself moves toward the rear of the optical axis 3 while rotating. Along with this movement, the lens barrel base plate 4d, that is, the lens barrel frame 4 resists the urging force of the lens barrel springs 27 and 28 and begins to retreat while being guided by the guide shafts 24-26.

On the other hand, if the first group drive screws 21 to 23, which are multi-threaded screws that are screwed into the female threads of the first group drive gear 16, are left-hand threads, the first group drive gear 16 itself tries to move forward, Since the position of the barrel substrate 4d in the optical axis direction is regulated, as a result, the first group driving screws 21 to 23 move to the rear of the optical axis 3. That is, the first group frame 6 starts retreating while being guided by the guide shaft (not shown) by the urging force of the first group springs 29 to 31.
In other words, the first group frame 6 is in the lens barrel frame 4 retracting with respect to the fixed frame 1 and further moves relative to the lens barrel frame 4 retracting.

Now, the reduction gear group 33a meshes with the annular gear 15 which rotates in the counterclockwise direction, and the third gear 37 as an output gear thereof.
The second group frame cam gear 9b is rotated counterclockwise via the second drive shaft 38. That is, the rotation of the ring gear 15 is reduced to a predetermined reduction ratio by the reduction gear group 33, and the second group frame 9 and the second group frame cam gear 9b are decelerated in the counterclockwise direction through the transmission member 33b. . At this time, the input gear 38a attached to the second drive shaft 38 of the transmission member 33b is engaged with the third gear 37, and the second drive shaft accompanying the backward movement of the first group frame 6 is engaged. Allow 38 backward movements. Thus, the cam pin 7b, which is in sliding contact with the cam surface 9a by the rotation of the second group frame cam 9, is pulled rearward by the second group springs 10a and 10b, and therefore moves diagonally rearward along the inclination of the cam surface 9a. However, the second group frame 7a includes the slider 7c.
Since only the linear movement in the optical axis 3 direction is allowed by the second group frame guide 8, as a result, it moves rearward in parallel to the optical axis 3.

When these operations proceed further and the cam pin 7b reaches the wide position (substantially V-shaped portion) of the cam surface 9a as shown in FIG. 11, it projects rearward from the first group substrate 6b of the second group frame 7a. The amount of rearward protrusion is maximized, and the protrusion member reaches immediately before the stopper portion 1e of the fixed portion 1. That is, as shown in FIG. 8, the front end of the lens barrel frame 4 (more specifically, the lens barrel 4a) is slightly extended from the front window 1a of the fixed frame 1, and the first group frame 6 (more specifically, the cylindrical portion 6).
a) is slightly extended from the front end of the lens barrel 4a, and the second group frame 7
It reaches a wide state in which a is retracted by the above-mentioned rearward protrusion amount.

Next, the storage operation from the wide state described above to the storage state shown in FIGS. 7 and 12 will be described. Lens drive gear
17 and the first group drive gear 16 rotate counterclockwise as described above. Therefore, the lens barrel frame 4 and the first group frame 6 continue to retreat as described above. However, as shown in FIG. 12, in the storage area where the storage operation is performed, the protruding member 54
Collides with the stopper portion 1e of the fixed frame 1, so that the second group frame 7a
Cannot retract further, and retains its position, but since the first group frame 6 (first group substrate 6b) and the lens barrel frame 4 are further retracted, the cam surface 9a is relatively in the second group spring. 10a, 10b
The cam pin 7b will be moved backwards against the spring force of. Then, as shown in FIG. 7, the lens barrel 4 and the first
The front ends of the group frames 6 are substantially aligned with the front plate 1a, and the rear protruding amount of the second group frame 7a is minimum (substantially zero), that is, the rear end of the second group frame 7a is The storage state is reached in which the first group substrate 6b is substantially aligned.

Next, from the storage state described above, FIG. 1, FIG. 9 and FIG.
The zooming operation in the long focal direction leading to the telephoto state shown in the figure will be briefly described.

By rotating the driving gear 11a in the counterclockwise direction by energizing the motor 11 with the current polarity reversed, all the lens barrel driving gear 17 and the first group driving gear 16 rotate in the clockwise direction. Accordingly, the lens barrel frame 4 extends forward, and the first group frame 6 further extends forward with respect to the lens barrel frame 4 extended. Further, focusing on only the first group frame 6 and the second group frame 7a, as shown in FIG. 12 and FIG. 11, the first group frame 6 (first group frame 6
Even if the group substrate 6b) is extended, the second group frame 7a is pulled by the first group substrate 6b by the second group spring 10a, so that the first group frame 6 only moves forward while maintaining its position. First to the position shown
Only when the group frame 6 moves forward is the first group frame cam 9 restricted. That is, the second group frame 7a has a cam surface between the storage state and the wide state, that is, in the storage area.
It is not subject to 9a regulations.

Further, the lens barrel frame 4 and the first group frame 6 move forward, the second group frame cam gear 9b rotates clockwise, and this rotation pushes the cam pin 7b slidably contacting the cam surface 9a obliquely forward, so that the slider The second group 7a is moved forward by being converted into a straight movement by the 7c and the second group frame guide 8. Then, as shown in FIG. 9 and FIG.
The group frames 6 extend substantially to the lens barrel frame 4, respectively, and the second group frame 7a also extends to the front of the first group substrate 6b by approximately the maximum amount.
The rear end of the group frame 7a reaches a tele state in which the rear end of the group frame 7a is substantially aligned with the first group frame 6b.

As described above, according to the present embodiment, the lens barrel frame 4 movably supported along the three guide shafts 24 to 26 substantially parallel to the optical axis 3 fixed to the fixed frame 1 includes: The first group frame 6 supporting the one lens group 5 is movably supported by a plurality of guide shafts (not shown) fixed to the lens barrel frame 4 in a state substantially parallel to the optical axis 3, and furthermore, the second group frame. A second group frame 7a supporting the second lens group 7 is supported by the cam 9 so as to be able to advance and retreat,
The first transmission mechanism portion driven via the drive shaft 13a and the moving gear 13b moves the lens barrel frame 4 forward and backward with the lens barrel drive screws 18 to 20 composed of three multi-threaded screws, and also the first group frame 6
With 3 first group drive screws 21-23 screws 21-23,
In accordance with the amount of movement of the first group frame 6, the second transmission mechanism 32 decelerates the annular gear 15 to a predetermined reduction ratio, and then the second gear
Since the group frame 9 is driven to rotate and the second group frame 7a is moved back and forth, the postures of the first lens group 5 and the second lens group 7 are moved along with the movement of the lens barrel frame 4 and the first group frame 6. There is an advantage in that the drawback of the conventional example that becomes unstable can be eliminated.

Furthermore, since the lens barrel frame 4 and the first group frame 6 advance and retreat double with respect to the fixed frame 1, in the retracted state, the optical system in the optical axis 3 direction of the entire apparatus in the housed state while having a variable focal length optical system having a large zoom ratio. The length is substantially the same as the length of the fixed frame 1 so that it is extremely small, and the second group frame 7a is not driven (is not restricted) by the cam surface 9a of the second group frame cam 9 in the storage area. Therefore, since the pressure angle of the cam surface 9a can be reduced, and the diameter of the second group frame cam 9 can be reduced, there is an advantage that further compactness can be realized.

Further, since the cam ring, which has been frequently used in the past, is not used for moving the lens barrel frame 4 and the first group frame 6, it is possible to save the high manufacturing cost required for manufacturing the cam ring and to manufacture it at low cost. .

Further, since the movement amount of the first group frame 6 and the lens barrel frame 4 can be easily set by the gear ratio of the transmission gear 14 composed of the two-stage gear, there is an advantage that the degree of freedom in design is large.

Further, the lens barrel driving screws 18 to 20 and the first group driving screw 21 to
23, the amount of movement of the lens barrel frame 4 and the first group frame 6 can be set by changing the leads,
There is an advantage that the degree of freedom in design, for example, the degree of freedom in disposing the optical leakage prevention mechanism is large.

Further, the lens barrel drive screws 18 to 20 are attached to the respective end portions 18a,
In 19a, 18b and 19b, the position is precisely regulated in the axial direction, but since there is an appropriate play (margin) in the circumferential direction, the lens barrel drive screws 18 to 20, the first group drive Even if there are errors in the manufacture of the screws 21 to 23, the lens barrel drive gear 17 and the first group drive gear 16 screwed to them, and the transmission mechanism as a whole, it does not apply excessive force to them, There is an advantage that a proper operation can be obtained and there is no fear that the motor 11 and the like are overloaded.

Further, since one rotation of the lens barrel drive gear 17 and the first group drive gear 16 is the movement of the lens barrel drive screws 18 to 20 and the first group drive screws 21 to 23 by one pitch, the advantage of high delivery accuracy is obtained. There is.

In addition, the second group springs 10a and 10b, the lens barrel springs 27 and 28, and the first group springs 29 to 31 can remove adverse effects such as backlash, so that there is an advantage that accuracy is further improved.

Further, since the first group frame cam 9 is driven to rotate directly from the annular gear 15 via the second transmission mechanism section 32, there is almost no stacking error in the rotation transmission system, and highly accurate scaling is possible. It becomes possible to operate.

Further, in the second transmission mechanism section 32, the reduction gear group
By providing the adjusting gear 35 in a part of 33a, the rotational angle positional relationship of the second group frame cam gear 9b can be adjusted, and thereby the positional relationship between the first lens group 5 and the second lens group 7 can be adjusted. Can be adjusted.

Further, the adjustment gear 35 is disposed outside the lens barrel substrate 4d and
Since the gear 34 and the second gear 36 are meshed with each other, the adjustment gear 35 is formed after the reduction gear group 33a and the transmission member 33b are assembled.
Can be finally assembled from the outside of the substrate 4c, and as a result, it is possible to assemble with good workability without giving importance to the performance of the lens.

Particularly, since the cross-sectional shape of the drive shaft 13a and the insertion hole 132 of the moving gear 13b are formed as described with reference to FIG.
The rotational force of 3a is F _1, and the rotational force transmitted to the moving gear 13b is F ₂
Then, F ₂ = F ₁ , and when the moving gear 13b transmits the rotational force while slidingly moving the drive shaft 13a, the frictional force F ₃ becomes F ₃ = μF ₂ (μ: coefficient of friction). As a result, the rotational force of the drive shaft 13a can be transmitted to the moving gear 13b with the highest transmission efficiency, and the moving gear 13b can slide the drive shaft 13a with less friction. The same can be said for the relationship between the second drive shaft 38 and the input gear 38a.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

For example, the cross-sectional shapes of the first drive shaft 13a and the second drive shaft 38 are not only drum-shaped but also a cutting surface 131a as a force transmitting surface for transmitting a rotational force to the transmitting member at a right angle as shown in FIG. In the shape of an arc or as shown in Fig. 14
Even if the three protrusions 131 having the 131a are equiangularly provided, the transmission efficiency can be increased similarly to the above. That is, the first in the embodiment of FIG. 2, FIG. 13 and FIG.
The cross-sectional shapes of the drive shaft 13a and the second drive shaft 38 and the shape of the insertion hole 132 of the moving gear 13b can be defined as follows.

First, as the shape of the insertion hole 132, a portion extending from the axial center of the moving gear 13b serving as the transmission member along the two radial lines extending divergently at a predetermined angle through the axial center 1
A plurality of fan-shaped insertion holes having a pair of receiving surfaces (132a) are formed at equal angular intervals, and a central side that communicates with the plurality of fan-shaped insertion holes is provided at a position closer to the center than the fan-shaped insertion holes. By forming the insertion hole, one insertion hole 132 is formed.

Further, the cross-sectional shape of the first drive shaft 13a will be described as a representative of the transmission shaft. Forces along the receiving surface 132a of the fan-shaped insertion hole near the outer peripheral portion of the first drive shaft 13a, respectively. A protrusion 131 having a transmission surface and having a shape substantially similar to the cross-sectional shape of the fan-shaped insertion hole is provided, and a thick portion continuous with the protrusion is provided at a portion closer to the center than the protrusion 131. The rigid portion 131b is integrally provided.

With such a configuration, the first drive shaft 13a
A state in which the cutting surface (force transmitting surface) 131a of the projecting portion 131 in FIG. 2 and the receiving surface 132a provided at a position distant from the axial center of the moving gear 13b are substantially rattling at a right angle or an angle close to a right angle in the rotation direction. The rotational force of the first drive shaft 13a can be accurately transmitted to the moving gear 13b most efficiently, and the moving gear 13b moves the driving shaft 13a in a frictionless state. It can slide smoothly.

Further, since the force transmission surface of the protrusion 131 is configured to contact the receiving surface 132a of the portion of the moving gear 13b farther from the shaft center, the force transmitting surface contacts the receiving surface of the portion closer to the shaft center. A larger torque can be transmitted as compared with the case of performing. In FIGS. 13 and 14, the same members as those shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

Further, as shown in the above embodiment, the lens barrel drive screws 18 to 20 do not necessarily have to be right-hand threads and the first group drive screws 21 to 23 need not be left-hand threads. It is needless to say that they are appropriately changed together.

Further, in the case of the above-mentioned embodiment, the lens barrel driving screws 18, 19, 20 have one end 18a, 19a, 20a as an oval shaft and the other end 18b, 19b, 2
Although 0b (however, 20b is not shown in the figure) is a round shaft, the oval shaft is a round shaft, and the degree of freedom in the direction of rotation is restricted (restricted) by friction, etc. The radial degrees of freedom of 17a, 17b, and 17c may be given to prevent the motor 11 and the like from being overloaded.

Similarly, the first group drive screws 21, 22, 23 similarly regulate (restraint) the degree of freedom in the rotational direction by friction or the like, and the degree of freedom by the screw or the radial direction of the first group drive gears 16a, 16b, 16c The motor 11 or the like may be configured so as not to be overloaded by giving a little degree of freedom. With this configuration,
The lens barrel drive screws 18-20 and the first group drive screws 21-
Since the degree of freedom of the rotation direction 23 is restricted so that it does not rotate, it is possible to perform a desired magnification change operation or storage operation by a screw action, while the lens barrel drive screw 18 is used during assembly adjustment. ~ 20 and first group drive screw 21 ~
23 can be freely rotated as appropriate.

As a result, firstly, the three lens barrel driving screws 18 to 20 and the three first group driving screws 21 to 23 are individually rotated as necessary to perform parallel adjustment at the time of assembly and desired optical performance. Secondly, it is possible to carry out parallel adjustment in order to bring out the effect, and secondly, it is possible to easily perform shift adjustment and back adjustment necessary for the variable focus lens. That is, since such advantages are obtained, it is possible to assemble the lens without giving importance to the performance of the lens at the time of assembling, and it is possible to remarkably improve the assembling workability.

As for the spring, in the above embodiment, a compression spring and a second spring are used as lens barrel springs 27 and 28.
Although tension springs are used as the group springs 10a and 10b and the first group springs 29 to 31, springs having the opposite functions may be used as long as the springs are selected.

Further, as the means for driving the first group frame 6 and the lens barrel frame 4, the example in which the screw is used has been described in the embodiment, but a drive mechanism such as a rack and a pinion may be used.

[Effects of the Invention] As is clear from the above description, according to the present invention, one or both of the transmission member such as a gear and the transmission shaft slides relatively in the axial direction of the transmission shaft. In the rotationally driven mechanism, firstly, the transmission of the rotational force from the transmission shaft to the transmission member or vice versa can be transmitted with the highest transmission efficiency, and secondly, in the sliding movement between the transmission shaft and the transmission member. The associated frictional force can be minimized, and thirdly,
Rotational force in both forward and reverse directions can be accurately transmitted with almost no rattling. Fourth, the force transmission strength is increased by providing a thick rigid portion on the center side of the transmission shaft. There is no risk of deformation, and transmission efficiency is good in this respect as well. Fifthly, since the force transmission surface of the transmission shaft and the receiving surface of the transmission member abut at a position apart from the shaft center, a larger rotational force is exerted. It is possible to provide a rotational force transmission mechanism that exhibits excellent practical effects such as transmission.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing the entire structure of an embodiment of a variable focus lens driving device having a rotational force transmission mechanism according to the present invention, and FIG. 2 is a rotational force transmission according to the present invention. FIG. 3 is an explanatory view for explaining the rotational force transmission action of the transmission shaft and the transmission member in the mechanism, and FIG. 3 is for explaining the transmission path of the driving force (rotational force) of the embodiment shown in FIG. FIG. 4 is a schematic view of the transmission mechanism section of FIG. 4 seen from the rear side of the optical axis. FIG. Figure 5 shows
FIG. 6 is a perspective view showing in enlarged detail the structure of both ends of the lens barrel drive screw 19 of FIG. 1 as a representative, and FIG.
7 is a vertical cross-sectional view showing in detail the configuration of the end portion on the side supported by the first group substrate 6b by taking the group driving screw 22 as a representative, FIG.
FIG. 9 schematically shows the three states associated with the operation of the embodiment shown in FIG. 1, among which FIG. 7 shows the storage state when not in use, as shown in FIGS. The figures are longitudinal sectional views respectively showing a wide state and a tele state in which the focal lengths are switched to the short focus side and the long focus side, respectively, and FIGS. 10 to 12 are the first group frame and the first group frame of the same embodiment. [Fig. 10] Fig. 10 is a side view schematically showing a part of the frame with a part broken to explain the operation with the second group frame. Of these, Fig. 10 is in a tele state, Fig. 11 is in a wide state, and Fig. 12 is It corresponds to the stored state. FIG. 13 and FIG. 14 are axial sectional views showing other examples of the rotational force transmission mechanism in the present invention, and FIG. 15 to FIG.
FIG. 17 is an axial sectional view of each of the conventional examples, and FIG. 18 is an explanatory view showing a rotational force transmission state between a conventional oval shaped transmission shaft and a transmission member. 1 ... Fixed frame, 1a ... Front plate, 1b ... Rear plate, 1c ... Front window, 1d ... Rear window, 1e ... Stopper part, 2 ... Third lens, 3 ... Optical axis, 4 …… Lens barrel frame, 4a …… Lens barrel, 4d ……
Lens barrel substrate, 5 ... First lens group, 6 ... First group frame, 6b ...
... 1st group substrate, 7 ... 2nd lens group, 7a ... 2nd group frame,
7b ... Cam pin, 8 ... Second group frame guide, 9 ... Second group frame cam, 9a ... Cam surface, 9b ... Second group frame cam gear, 10a,
10b ... second group spring, 11 ... motor, 12 ... reduction gear train, 13 ... driving gear, 13a ... first driving shaft, 13b ... moving gear, 14 (14a, 14b, 14c) ... … Transmission gear, 15 …… Toroidal gear, 16 (16a, 16b, 16c) …… First group drive gear, 17 (17
a, 17b, 17c) …… Lens barrel drive gear, 18-20 …… Lens barrel driving screw, 21-23 …… First group driving screw, 24-26 …… Guide shaft,
27,28 …… Body barrel spring, 29〜31 …… First group spring, 32
...... Second transmission mechanism section, 33a ...... Reduction gear group, 33b ...... Transmission member, 38 ...... Second drive shaft, 38a ...... Input gear, 38b ...
… Output gear, 131… Projection, 131a… Cutting surface, 131b…
… Rigid part, 132 …… insertion hole.

Claims (1)

[Scope of utility model registration request] 1. A transmission member, such as a gear, and a transmission shaft for transmitting and receiving a rotational force to and from the transmission member, and one or both of the transmission member and the transmission shaft is the shaft of the transmission shaft. In a rotational force transmission mechanism that transmits and receives a rotational force while slidingly moving in the axial direction, a portion distant from the shaft center of the transmission member is along two radial lines that extend through the shaft center and spread out at a predetermined angle. A plurality of fan-shaped insertion holes having a pair of receiving surfaces are formed at equal angular intervals, and a portion closer to the center than the fan-shaped insertion holes is
A center-side insertion hole that communicates with the plurality of fan-shaped insertion holes is formed, and a force transmission surface that extends along the receiving surface of the fan-shaped insertion hole is provided in the vicinity of the outer peripheral portion of the transmission shaft. A protrusion having a shape substantially similar to the cross-sectional shape of the fan-shaped insertion hole is provided, and a thick rigid portion continuous with the protrusion is provided at a portion closer to the center than the protrusion. Portion is configured to transmit a rotational force at a right angle or an angle close to a right angle to the rotation direction with the receiving surface provided at a position apart from the axial center of the transmission member. mechanism.