JP2002090611A - Lens barrel and optical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a tapered roller from falling off from a cam groove, even if external force is exerted on the lens barrel in the optical axis direction and the lens barrel is deformed. SOLUTION: This lens barrel is provided with a cylindrical roller (roller-type member) 117 inserted in grooves (falling-off preventing groove part) 107f and 107g formed along a cam groove 107c on the outer periphery of a cam ring 107 on the inner periphery of a 1st lens frame 108.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital camera,
The present invention relates to a lens barrel used for an optical device such as a video camera, a silver halide camera, and binoculars.

[0002]

2. Description of the Related Art In a lens barrel used for a camera or the like,
A plurality of lens barrels are cam driven relatively in the optical axis direction to perform a magnification change operation or the like. In this lens barrel, a tapered cam follower is engaged with the tapered cam groove in order to reduce the fluctuation of the lens position due to the engagement between the cam groove and the cam follower.

[0003] Here, the angle of the cutting edge formed by the lens barrel radial direction and the wall surface of the cam groove is set to be somewhat large in order to allow the mold to be pulled out in the lens barrel radial direction during molding. Therefore, when an external force is applied to the lens barrel in the optical axis direction, the cam follower may slide on the wall surface of the cam groove and fall off the cam groove.

[0004] Therefore, there has been proposed a lens barrel in which the cam follower can be prevented from falling off from the cam groove. One example of this lens barrel is shown in FIGS. FIG. 16 is a sectional view of a lens barrel, and FIG. 17 is a perspective view of a first lens barrel 174 constituting the lens barrel.

In this lens barrel, a tapered roller (cam follower) 173 provided in the second barrel 175 is engaged with a cam groove 172 formed on the outer peripheral surface of the first barrel 174.
By rotating the first lens barrel 174, the second lens barrel 1 is rotated.
75 is cam-driven in the optical axis direction.

[0006] On the outer peripheral surface of the first lens barrel 174, a fall-off preventing groove 170 formed along the cam groove 172 is provided.
Cylindrical roller-shaped member 171 provided in second lens barrel 175
Is inserted. When an external force is applied to the lens barrel in the direction of the optical axis, the fall prevention groove 170 and the roller-shaped member 171 come into contact with each other, so that the cam groove 172 is formed.
And the taper roller 173 are prevented from being disengaged.

By the way, the first of the fall prevention grooves 170
The portion of the lens barrel 174 on the object side is formed by pulling out the mold toward the object side, and therefore, as shown in FIG. 17, the wall surface is formed only on the image surface side, and does not form a groove. Therefore, the portion of the fall-off prevention groove 170 on the object side of the first lens barrel 174 is particularly referred to as a fall-off prevention wall 170.

For this reason, the groove wall 170 for preventing falling off from the object side
If the external force F ₁ is applied toward, a large angle between the wall and the barrel radial cam grooves 172 (e.g., 55
°), the tapered roller 173 slides on this wall surface and attempts to fall off from the cam groove 172. However, since the roller-shaped member 171 comes into contact with the falling-off preventing groove wall 170 which is cut out substantially in parallel with the lens barrel radial direction, the tapered roller 173 is contacted. From the cam groove 172 can be suppressed.

[0009]

[0007] However, if the external force F ₂ applied toward the object side from the image side, there is no falling-off preventing walls 170 abutting the roller-shaped member 171,
It is impossible to prevent the tapered roller 173 from falling off from the cam groove 172. Further, since the tapered roller 173 applies an excessive load to the wall surface on the image surface side of the cam groove 172, the wall surface may be dented or damaged.

Accordingly, an object of the present invention is to provide a lens barrel which suppresses the tapered roller from dropping out of the cam groove even when an external force is applied to the lens barrel in the optical axis direction and the lens barrel is deformed. And

[0011]

In order to achieve the above object, a lens barrel according to the present invention has a cam groove formed with a tapered cam surface on a peripheral surface of a first lens barrel. 2 By engaging a tapered cam follower provided in the lens barrel,
The lens barrel and the second lens barrel are relatively drivable in the axial direction of the lens barrel, and mutually opposing wall surfaces of drop-out preventing grooves formed along the cam groove on the peripheral surface of the first lens barrel. Between the cam barrel and the cam follower by contacting the roller-shaped member provided on the second lens barrel with the wall of the drop-prevention groove. Therefore, the angle at which the wall surface of the fall-prevention groove portion stands up with respect to the lens barrel radial direction differs in the lens barrel circumferential direction.

Thus, when an external force is applied in the direction of the optical axis, the opposing wall surface of the fall-prevention groove portion and the roller-shaped member come into contact regardless of the direction of the external force. Can be prevented from being disengaged. Further, since the load applied by the cam follower to the wall surface of the cam groove is small, the wall surface is not dented or damaged.

The drop-off prevention groove is formed to extend to one side in the lens barrel axial direction on the peripheral surface of the first lens barrel. The peripheral surface having the falling-off preventing groove is formed by pulling out the mold perpendicular to the optical axis direction.

When the molding die is pulled out, the portion of the molding die that is pulled out in the lens barrel radial direction may be provided in parallel with the lens barrel radial direction, in which the wall of the fall prevention groove portion in which this part is buried is provided. Since this wall surface and the pulling-out direction are parallel to each other, it is possible to pull out without receiving a load from this wall surface.

On the other hand, the part of the molding die which is separated in the lens barrel circumferential direction from the part which is pulled out in the lens barrel radial direction is the wall in which this part of the falling-off preventing groove is filled in the lens barrel radial direction. If they are provided in parallel, it is difficult to pull them out because they receive the load from the one wall surface.

Therefore, the angle of the cut-away direction of the one side wall corresponding to the separated portion is set to be larger than 0 °.
That is, the wall surface on one side is formed to be inclined from the lens barrel radial direction. As a result, the load applied to the separated portion from the corresponding one side wall surface is reduced, so that the separated portion can be pulled out from the fall prevention groove.

As described above, by making the cut-off angle of the wall surface of the fall-prevention groove different according to the direction in which the mold is pulled out with respect to the fall-prevention groove and the direction in which the fall-prevention groove extends, the drawing-out of the molding die can be carried out smoothly. I can do it.

Under these conditions, by forming the wall surface as parallel as possible in the circumferential direction of the lens barrel, disengagement between the cam groove and the cam follower can be suppressed more reliably.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIGS. 1 to 6 show the overall structure of a lens barrel according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of the lens barrel. FIG. 2, FIG.
4 is a sectional view of the lens barrel. FIG. 2 shows a retracted state, FIG. 3 shows a wide state, and FIG. 4 shows a telescopic state. FIG.
6 and 7 show the configuration of the cam ring 107 in an enlarged manner. FIG. 5 is a perspective view, and FIG.

Reference numeral 101 denotes a body attached to a camera body (not shown). The body 101 supports the entire lens barrel when attached to the camera body. 102, 10
Reference numerals 3, 104, and 105 denote first, second, and third movable members arranged in the optical axis direction from the front to the rear, respectively.
And a fourth moving lens.

Reference numeral 106 denotes a fixed frame fixed inside the main body 101 in the radial direction, and 107 denotes a cam ring (first lens barrel) sandwiched between the main body 101 and the fixed frame 106 in the radial direction. A groove 107q extending in the circumferential direction is provided on the inner periphery of the cam ring 107, and a protrusion 106b provided on the outer periphery of the fixed frame 106 is engaged with the groove 107q.

As a result, the cam ring 107 rotates around the optical axis without moving in the optical axis direction by transmitting the rotational driving force from the step gear 132 meshing with the cam ring 107, as described later. Can be. In addition, the fixed frame 106
The inner diameter rib 107a, which is the rear end of the cam ring 107, is
The cam ring 107 is stably held with respect to the fixed frame 106 because the cam ring 107 is held by the abutting portion 106a.

Reference numeral 108 denotes a first lens frame (second lens barrel) for holding the first movable lens 102.

The first lens frame 108 is radially sandwiched between the main body 101 and the cam ring 107, and the outer periphery of the main body 1 is
01 is provided on the inner periphery of the cam ring 107 and a cam groove (cam groove) 107 formed on the outer periphery of the cam ring 107.
A tapered roller (cam follower) 109 that engages with c is provided.

As a result, when the cam ring 107 rotates around the optical axis, the first lens frame 108 is guided by the tapered roller 109 and the cam while being linearly guided in the optical axis direction by the engagement between the projection 108a and the rectilinear groove 101a. It is driven straight forward in the optical axis direction by the engagement with the groove 107c.

Further, on the inner periphery of the first lens frame 108,
On the outer periphery of the cam ring 107, there are provided cylindrical cylindrical rollers (roller-shaped members) 117 to be inserted into grooves (fall-preventing groove portions) 107f and 107g formed along the cam groove 107c. The width of the grooves 107f and 107g is slightly wider than the width of the cylindrical roller 117. The groove 107f corresponds to a non-photographing area (collapsed state to telephoto state), and the groove 107g corresponds to a photographing area (telephoto state to wide state).

Accordingly, when an external force is applied in the optical axis direction to the first lens 102, the first lens frame 108, or the display sheet 110 such as a lens name attached to the front of the first lens frame 108. The roller 117 and the groove 107
f or 107 g abuts against the taper roller 109 and the cam groove 10 regardless of the direction of the external force.
7c can be prevented from being disengaged. Further, since the load applied to the wall surface of the cam groove 107c by the tapered roller 109 is small, the wall surface is not dented or damaged.

The shape of the wall surface of the groove 107g will be described later.

[0029] 111, 112, 113 and 114 are
The bars are fixed at both ends by the main body 101 and the fixed frame 106, and the bars 111, 112, 113 and 114 are arranged radially inside the fixed frame 106 in parallel with the optical axis.

Reference numeral 115 denotes a second lens frame for holding the second lens 103.

The second lens frame 115 is provided with a sleeve 115a fitted to the bar 111 and a U-shaped groove 115b engaged with the bar 112. As a result, the second lens frame 115 is guided linearly in the optical axis direction by the fitting action between the bar 111 and the sleeve 115a.
The engagement between the U-shaped groove 12 and the U-shaped groove 115b restricts rotation around the optical axis.

The second lens frame 115 includes a cam ring 1.
07 is provided with a tapered roller 116 which engages with a cam groove 107d formed on the inner periphery of the roller. As a result, when the cam ring 107 rotates around the optical axis, the second lens frame 115 moves in the cam groove 107d while being guided straight in the optical axis direction.
Due to the engagement action between the taper roller 116 and the taper roller 116, the linear drive is performed in the optical axis direction.

Reference numeral 118 denotes a third lens frame for holding the third lens 104.

The third lens frame 118 is provided with a sleeve 118a fitted to the bar 113 and a U groove 118b engaged with the bar 114. Thus, the third lens frame 118 is guided straight in the optical axis direction by the fitting action of the bar 113 and the sleeve 118a, and
The engagement between the U-shaped groove 14 and the U-shaped groove 118b restricts rotation around the optical axis.

The third lens frame 118 includes a cam ring 1.
07 is provided with a tapered roller 119 which engages with a cam groove 107e formed on the inner periphery of the roller. Thus, when the cam ring 107 rotates around the optical axis, the third lens frame 118 is guided in the cam groove 107e while being guided straight in the optical axis direction.
Due to the engagement between the taper roller 119 and the taper roller 119, the linear drive is performed in the optical axis direction.

Reference numeral 120 denotes an aperture device mounted on the third lens frame 118, and 121 is disposed in the long side direction of the photographed image.
An aperture motor 122 for driving the aperture device 120 transmits a control signal from control means (not shown) of the camera body to the inside of the lens barrel, and is an FPC having a bent portion 122a that is deformed as the aperture device 120 moves. is there. Aperture motor 1
21 is driven by a control signal transmitted from the FPC 122.

A fourth lens frame 123 holds the fourth lens 104.

The fourth lens frame 123 is provided with a sleeve 123a fitted to the bar 113 and a U-shaped groove 123b engaged with the bar 114. As a result, the fourth lens frame 123 is connected to the bar 113 similarly to the third lens frame 118.
The linear movement guide is guided in the optical axis direction by the fitting action between the sleeve 114a and the sleeve 123a, and the bar 114 is restricted from rotating around the optical axis by the engaging action between the bar 114 and the U groove 123b. Note that, as will be described later, a straight driving force in the optical axis direction is transmitted to the fourth lens frame 123 from a rack 126 attached to the fourth lens frame 123.

As described above, since the third lens frame 118 and the fourth lens frame 123 are both guided straight by the bars 113 and 114, these bars 113 and 11
Even if there is a displacement of 4, the relative displacement and inclination between the third lens frame 118 and the fourth lens frame 123 can be reduced.

Reference numeral 126 denotes a rack attached to the fourth lens frame 123. The rack 126 includes a coil spring 125
While receiving the rotational driving force from the feed screw 128 which is the output shaft of the stepping motor 127 disposed in the short side direction of the photographed image while being shifted in the optical axis direction by the, the fourth lens frame 123 is moved in the optical axis direction. Move to

Reference numeral 129 denotes a motor holding member for holding the feed screw 128. Fixed frame 106, second lens frame 11
5, after the third lens frame 118 and the fourth lens frame 123 are sequentially incorporated into the main body 101 from the rear, the motor holding member 129 is incorporated, and the stepping motor 12
7, a motor fixing portion 129a arranged near the driving portion
To the main body 101 in the optical axis direction.

Since the motor holding member 129 is disposed radially displaced from the rack 126 and the fourth lens frame 123, the rack 126 and the fourth lens frame 1
23 does not interfere.

Reference numeral 130 denotes a stepping motor with a speed reducer for rotating the cam ring 107 around the optical axis, and is attached to the main body 101. The stepping motor 130 is arranged near the short side of the captured image and near the optical axis. On the other hand, the above-described stepping motor 127
Are arranged in the short side direction opposite to the position of the stepping motor 130.

Thus, the stepping motor 127
And 130 are arranged close to the optical axis, so that these stepping motors 127 and 130
The diameter of the cam ring 107 arranged on the outer peripheral side can be reduced. Therefore, the lens barrel can be downsized.

A gear 131 is rotatably mounted on the main body 101 and meshes with an output gear of the stepping motor 130. 132 is a step gear having a large gear portion 132a and a small gear portion 132b,
Meshes with the gear 131, and the small gear portion 132b
07 is engaged with the outer peripheral gear portion 107i.

The rotational driving force of the stepping motor 130 is transmitted to the outer peripheral gear 107i via the gear 131, the large gear 132a and the small gear. Thus, the cam ring 107 is driven to rotate about the optical axis.

Reference numeral 133 denotes a stopper fixed to the main body 101. The stopper 133 regulates the rotation of the cam ring 107 by restricting the step gear 132 in the optical axis direction and abutting the projection 107j of the cam ring 107 in the rotational direction with the rotation stopper 133a.

The stopper 133 regulates the rotation of the cam ring 107, so that the tapered roller 109, the tapered roller 116, the tapered roller 119, and the cylindrical roller 117 are provided.
Are the cam groove 107c and the cam groove 107 with which they are engaged.
d, It is not necessary to come off from the roller groove mounting position of the cam groove 107e and the groove 107g. FIG. 6 shows the roller assembling position 107r of the cam groove 107c and the groove 107g.

Reference numeral 134 denotes a cam ring rotation position detecting device for detecting the position of the projection 107h of the cam ring 107 by a sensor, and 135 denotes a fourth lens position for detecting the light-shielding protrusion 123c of the fourth lens frame 123 by a sensor. It is a detection device.

136 Each control signal from the control means of the camera body is transmitted to the stepping motor 127, the stepping motor 130, the cam ring rotational position detecting device 134 and the fourth
This is an FPC for transmitting to the lens position detection device 135.

Next, the operation of the lens barrel will be described.

First, the operation of the lens barrel from the collapsed state to the wide state will be described.

A control signal for changing the lens barrel from the collapsed state to the wide state is transmitted from the control means of the camera body to the FPC1.
When transmitted to the stepping motor 130 via 36, the stepping motor 130 rotates in a predetermined direction around the optical axis. This rotational driving force is transmitted to the outer peripheral portion 107i of the cam ring 107 via the gear 131 and the step gear 132, so that the cam ring 107 rotates around the optical axis.

Thus, the first lens frame 108 is guided linearly in the optical axis direction by the engagement between the projection 108a and the rectilinear groove 101a, while being guided in the optical axis direction by the engagement between the tapered roller 109 and the cam groove 107c. Is driven straight ahead. During this time, the cylindrical roller 117 is engaged with the groove 107F (FIG. 6).

Further, the second lens frame 115 is
The cam groove 107d and the tapered roller 11 are guided linearly in the optical axis direction by the fitting action between the cam groove 107d and the sleeve 115a.
6 is driven straight forward in the optical axis direction.

Further, the third lens frame 118 is
The cam groove 107e and the tapered roller 11 are guided linearly in the optical axis direction by the fitting action between the cam groove 107e and the sleeve 118a.
9 is driven linearly in the optical axis direction.

During this time, the cam ring rotational position detecting device 134
Detects the protrusion 107 of the cam ring 107 with a sensor,
This detection result is output to the control means of the camera body via the FPC 136. The control means of the camera body controls the number of pulses of the stepping motor 130 based on the detection result.

On the other hand, a control signal for changing the lens barrel from the retracted state to the wide state is transmitted from the control means of the camera body to the F signal.
When transmitted to the stepping motor 127 via the PC 136, the stepping motor 127 rotates in a predetermined direction around the optical axis. When this rotational driving force is transmitted to the rack 126 via the feed screw 128, the rack 126 moves in the optical axis direction. Thereby, the fourth lens frame 123 to which the rack 126 is attached also moves in the optical axis direction.

During this time, the stepping motor 127
The light-shielding projection 123c of the fourth lens frame 123 is detected by a sensor, and the detection result is output to the control means of the camera body via the FPC 136. The control means of the camera body controls the number of pulses of the stepping motor 127 based on the detection result.

The zoom operation of the lens barrel is the same as the above-described operation of the lens barrel. However, the cylindrical roller 11 engaged with the groove 107F from the wide state to the collapsed state
7 enters the zoom groove 107g from the groove 107F when entering the wide state, and engages with the groove 107g in the photographing state (FIG. 6).

Next, the operation of the lens barrel from the photographing state to the collapsed state will be described. A control signal for changing the lens barrel from the photographing state to the collapsed state is transmitted from the control means of the camera body via the FPC 136 to the stepping motor 1.
27, the stepping motor 127
The fourth lens frame 123 rotates in a direction opposite to the above-described predetermined direction so as to move to the retracted position without interfering with another lens frame.

On the other hand, a control signal for changing the lens barrel from the photographing state to the collapsed state is transmitted from the control means of the camera body to the FP.
When transmitted to the stepping motor 130 via C136, the stepping motor 130 rotates around the optical axis in a direction opposite to the above-described predetermined direction. Thus, the first lens frame 108, the second lens frame 115, and the third lens frame 1
Reference numeral 18 moves to each retracted position.

Next, the shape of the groove 107g will be described with reference to FIGS.
Explanation will be made using 0.

FIGS. 7, 8 and 9 are cross-sectional views of the cam ring 107. FIG. 7 is a cross-sectional view taken along a cross-sectional line AA of FIG. 6 (wide state), and FIG. FIG. 9 shows a cross section taken along section line CC in FIG. 6 (intermediate state). FIG. 10 is a cross-sectional view for explaining the drawing of the molding die 300 from the cam ring 107.

The outer periphery of the cam ring 107 is formed by six molds. The outer periphery of the cam ring 107 is formed by pulling out a mold perpendicular to the optical axis direction.

In FIG. 6, boundary lines 302a to 302g
Indicates the boundaries of the six molds arranged on the outer periphery during molding. The cross-sectional lines AA, BB, and CC each have a boundary line 302b and 302c.
include. In FIG. 6, the section line CC is located on the left side of the specific area 304 from which the mold is drawn in the lens barrel radial direction, and the section lines AA and BB are located on the right side of the specific area 304.

In the AA cross section, the direction of the groove 107g is orthogonal to the optical axis. Therefore, even if the wall surface of the groove 107g is provided in parallel with the lens barrel radial direction, the wall surface and the drawing direction are parallel to each other. Therefore, when the mold 300 is pulled out, the mold 300 can be pulled out without receiving a load from the wall surface of the groove 107g. The angle a of the cutting direction of the wall surface of the groove 107g with respect to the lens barrel radial direction is about 0 °.

In the BB section, the direction of the groove 107g is greatly inclined with respect to the direction orthogonal to the optical axis.
When the wall surface of 7 g is provided in parallel with the lens barrel radial direction, since the wall surface and the pulling-out direction are not parallel to each other, when the molding die 300 is pulled out, the load from the wall surface on the object side of the groove 107 g at the time of pulling out the molding die 300. Receive. For this reason, pulling out becomes difficult. Therefore, the angle b of the cut-away direction of the wall surface on the object side of the groove 107g in the BB section is provided so that the mold 300 can be pulled out. Further, the angle b of the wall surface on the image side is set equal to the angle b of the wall surface on the object side. Thereby, both wall surfaces can be processed by one cutter.

In the CC section, the direction of the groove 107g is the same as the groove 107g in the BB section with respect to the direction orthogonal to the optical axis.
The mold 300 can be pulled out even if the cut-out direction angle c on the image surface side of the groove 107g is smaller than the angle b. By thus forming the wall surface as close as possible to the lens barrel circumferential direction as much as possible, the disengagement between the cam groove 107c and the tapered roller 109 can be suppressed more reliably. B-
Similar to the section B, the angle c of the cutting edge of the wall surface on the object side
Is made equal to the angle c of the cutting edge of the wall surface on the image plane side. Thereby, both wall surfaces can be processed by one cutter.

In the groove 107g, for example, the cross section C
In the case where the region of -C is the first arbitrary region and the region of the cross section BB is the second arbitrary region, the second arbitrary region is closer to the objective side (one side in the optical axis direction of the lens barrel) than the first arbitrary region. The angle b of the wall surface on the object side in the second arbitrary region is larger than the angle c of the wall surface on the object side in the first arbitrary region.

According to the above-described structure, the cut-off angle of the wall surface of the groove 107g can be adjusted with respect to the groove 107g.
The shape of the molding die 300 can be smoothly extracted by making the shape of the mold 300 different depending on the direction in which the mold 107 is pulled out and the direction in which the groove 107g extends.

(Second Embodiment) Next, the shape of a groove 107g according to a second embodiment will be described with reference to FIGS.

FIG. 11 is a developed view of the outer surface of the cam ring 107. 12, 13, and 14 are cross-sectional views of the cam ring 107. FIG. 12 is a cross-sectional view taken along a cross-sectional line DD in FIG. 11 (wide state), and FIG. 14 shows a cross section (intermediate state) and FIG. 14 shows a cross section (intermediate state) taken along section line FF in FIG. The sectional lines DD, EE, and FF of the second embodiment are cross-sectional lines AA, BB, and C-, respectively, of the first embodiment.
C is supported. The same contents as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the DD section, similarly to the AA section, the groove 107g is raised so as to be substantially parallel to the lens barrel radial direction. That is, the angle d at which the wall surface of the groove 107g stands in the cutting direction with respect to the lens barrel radial direction is about 0 °.

In the EE section, as in the case of the BB section, a large cut-off direction angle e is provided on the wall surface side of the groove 107g in order to enable the mold 300 to be pulled out.

In the FF section, similarly to the CC section, the cutting direction angle f on the wall surface side of the groove 107g is smaller than the cutting direction angle e in order to enable the mold 300 to be pulled out. Provided.

By the way, in a region on the DD side from the specific region 304, the groove 107g is curved toward the object side as the region is farther from the specific region 304 in the lens barrel radial direction.
When the wall surface on the objective side of the groove 107g is parallel to the lens barrel radial direction, the farther the above-mentioned region is in the portion of the mold 300 where the groove 107g is buried, the more the cam ring 1
At the time of pulling out from the outer periphery of 07, it is blocked by the wall surface on the object side of the groove 107g and receives a large load from this wall surface.

Therefore, as shown in FIG. 11, as the region (second arbitrary region) is farther from the region (first arbitrary region) on the side of the specific region 304 in the lens barrel radial direction, the cut-off angle of the groove 107g on the wall surface side is increased. Is continuously increased, the load force is reduced, and the mold 300 can be pulled out smoothly.

On the other hand, even when the wall surface on the image surface side of the groove 107g is formed parallel to the lens barrel radial direction, the groove 107g of the molding die 300 is filled when the molding die 300 is pulled out. That portion is not obstructed by the wall surface of the groove 107g on the camera body side.

Therefore, in the second embodiment, the image-side wall surface of the groove 107g is formed parallel to the lens barrel radial direction. Thereby, the cam groove 107c and the tapered roller 116
Can be more reliably suppressed from being disengaged.

The same applies to the area on the EE side from the specific area 304. However, in this case, since the groove 107g is curved toward the image surface side in a region farther from the specific region 304 in the lens barrel radial direction, the shape of the wall surface of the groove 107g is a region on the DD side from the specific region 304. And the optical axis direction.

(Third Embodiment) FIG. 15 is a developed view of the outer surface of a cam ring 107 according to a third embodiment.

In the second embodiment, the cutting direction angle in the groove 107g is changed continuously, but in the third embodiment, the cutting direction angle is changed intermittently. This point is different from the second embodiment. Also in this case, the molding die 300 can be pulled out smoothly from the cam ring 107.

Note that the present invention is not limited to the above-described embodiment, and various changes can be made according to the design.

For example, in the above-described embodiment, the lens barrel is used for a camera, but may be used for binoculars or other optical devices.

[0086]

As is apparent from the above description, according to the lens barrel of the present invention, the lens barrel of the present invention has a tapered cam surface formed on the peripheral surface of the first lens barrel. The tapered cam follower provided in the second lens barrel is engaged with the cam groove, so that the first lens barrel and the second lens barrel can be relatively driven in the axial direction of the lens barrel, and A roller-shaped member provided in the second lens barrel is inserted between opposing wall surfaces of the drop-prevention grooves formed along the cam groove on the peripheral surface of the first lens barrel, and A lens barrel that suppresses disengagement of a cam groove and a cam follower by contact between a wall surface and a roller-shaped member, wherein a cut-off angle of a wall surface of a fall-prevention groove portion with respect to a lens barrel radial direction is in a lens barrel circumferential direction. different.

Thus, when an external force is applied in the direction of the optical axis, regardless of the direction of the external force, the opposing wall surface of the fall-prevention groove portion and the roller-shaped member come into contact with each other. Can be prevented from being disengaged. Further, since the load applied by the cam follower to the wall surface of the cam groove is small, the wall surface is not dented or damaged. Further, by making the cut-off angle of the wall surface of the fall-preventing groove different according to the direction in which the mold is pulled out with respect to the fall-preventing groove and the direction in which the fall-preventing groove extends, the drawing-out of the mold can be performed smoothly.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a lens barrel.

FIG. 2 is a cross-sectional view of the lens barrel in a collapsed state.

FIG. 3 is a cross-sectional view of the lens barrel in a wide state.

FIG. 4 is a sectional view of the lens barrel in a telephoto state.

FIG. 5 is an enlarged perspective view of a cam ring.

FIG. 6 is a development view of an outer surface of a cam ring.

FIG. 7 is a sectional view of the cam ring taken along a sectional line AA in FIG. 6;

FIG. 8 is a sectional view of the cam ring taken along a section line BB in FIG. 6;

FIG. 9 is a cross-sectional view of the cam ring taken along a line CC in FIG. 6;

FIG. 10 is a cross-sectional view for explaining pulling out of a molding die from a cam ring.

FIG. 11 is a development view of an outer surface of a cam ring.

FIG. 12 is a sectional view of the cam ring taken along a section line DD in FIG. 11;

FIG. 13 is a sectional view of the cam ring taken along a section line EE in FIG. 11;

FIG. 14 is a sectional view of the cam ring taken along a section line FF in FIG. 11;

FIG. 15 is a development view of an outer surface of a cam ring.

FIG. 16 is a sectional view of a lens barrel.

FIG. 17 is a perspective view of a first lens barrel.

[Explanation of symbols]

 101: main body 102: first moving lens 103: second moving lens 104: third moving lens 105: fourth moving lens 106: fixed frame 106a: abutting portion 106b: projecting portion 107: cam ring 107a: Inner diameter rib 107c: cam groove 107d: cam groove 107e: cam groove 107F: groove 107g: vertical surface 107h: protrusion 107i: outer peripheral gear part 108: first lens frame 109: taper roller 110: sheet 111: bar 112: bar 113: Bar 114: Bar 115: Second Lens Frame 116: Tapered Roller 117: Cylindrical Roller 118: Third Lens Frame 118a: Sleeve 118b: U Groove 119: Tapered Roller 120: Aperture Device 121: Aperture Motor 122: Aperture FPC 123 : Fourth lens frame 123a: sleeve 123b: U groove 123c: light shielding projection 124: lens holding plate 125: coil spring 126: rack 127: stepping motor 128: feed screw 129: motor holding member 129a: motor fixing unit 130: stepping motor 131: gear 132: step gear 132a: large gear unit 132b: Small gear portion 133: Stopper 133a: Rotation stopper portion 134: Cam ring rotation position detecting device 140: First lens frame 141: Taper roller 142: Taper roller 143: Cylindrical roller 144: Cylindrical roller 145: Cam ring

Claims (9)

[Claims] 1. A tapered cam follower provided in a second lens barrel is engaged with a cam groove formed by forming a tapered cam surface on a peripheral surface of a first lens barrel. The lens barrel and the second lens barrel are relatively drivable in the axial direction of the lens barrel, and at the same time, two of the falling-off preventing grooves formed along the cam groove on the peripheral surface of the first lens barrel. A roller-shaped member provided in the second lens barrel is inserted between opposing wall surfaces, and the cam groove and the cam follower are disengaged from each other by abutting the wall surface of the drop-prevention groove and the roller-shaped member. A lens barrel, wherein a cut-off angle of a wall surface of the fall-prevention groove with respect to a barrel radial direction is different in a circumferential direction of the barrel. 2. A second arbitrary area on the peripheral surface of the first lens barrel, wherein a second arbitrary area extends to one side in the lens barrel axial direction from a first arbitrary area of the drop-prevention groove, and the second arbitrary area. 2. The lens barrel according to claim 1, wherein a cutting direction angle of the one-side wall surface is larger than a cutting direction angle of the one-side wall surface in the first arbitrary region. 3. The lens barrel according to claim 2, wherein the angle of the cut-away direction of the one side wall increases continuously from the first arbitrary region to the second arbitrary region. 4. The lens barrel according to claim 2, wherein the angle of the cut-off direction of the one wall surface increases stepwise from the first arbitrary region to the second arbitrary region. 5. The lens mirror according to claim 2, wherein a wall surface on the other side of the fall-prevention groove is stood so as to be substantially parallel to a lens barrel radial direction. Tube. 6. A cut-off angle of a wall surface on the other side of the fall-prevention groove is substantially equal to a cut-off angle of a wall on one side of the drop-prevention groove.
5. The lens barrel according to any one of 4. 7. The falling-off preventing groove portion is formed by pulling out a molding die in a lens barrel radial direction, wherein the second arbitrary region is larger in the lens barrel radial direction than the first arbitrary region. The lens barrel according to claim 2, wherein the lens barrel is a region farther than a region to be pulled out. 8. The lens barrel according to claim 1, wherein a maximum cutting angle of a wall surface of the fall-prevention groove is smaller than a cutting angle of a wall surface of the cam groove. . 9. An optical apparatus comprising the lens barrel according to claim 1.