JPH0654013U - Linear guide mechanism for zoom lens barrel - Google Patents

Abstract

(57) [Summary] [Purpose] A zoom lens barrel capable of ensuring a sufficient movement stroke of the straight guide plate without impairing the strength of the single component when the straight guide groove is provided in the fixed ring. To provide a straight-ahead guide mechanism. [Structure] A fixed ring to be fixed to the camera body side, a cam ring screwed to the inner circumference of the fixed ring, and a linear guide capable of relative rotation with respect to the cam ring and movable along with the cam ring in the optical axis direction. Plate, a linear guide groove for guiding the linear guide plate in the optical axis direction, and a lens group forming a zoom lens which is guided in the optical axis direction by the linear guide plate and whose position in the optical axis direction is determined by a cam ring. In a linear guide mechanism for a zoom lens barrel having a linear guide groove, the linear guide groove is provided along the optical axis direction of the fixed ring, and a part of the linear guide groove is provided in a radial bottom portion of the fixed ring. A linear guide mechanism for a zoom lens barrel configured as a closed groove with a closed bottom.

Description

[Detailed description of the device]

[0001]

【Technical field】

 The present invention relates to a rectilinear guide mechanism for a zoom lens barrel, and more particularly to a rectilinear guide mechanism for a zoom lens barrel having a lens group that is guided by a rectilinear guide plate that is rectilinearly guided by a rectilinear guide groove.

[0002]

[Prior art and its problems]

 For example, a cam ring is screwed (helicoidally coupled) to the inner circumference of a fixed ring to be fixed to the camera body side, and this cam ring is driven to rotate so that a plurality of lens groups in the cam ring are optically driven. In a camera that performs zooming by moving in a predetermined relationship in the axial direction, this lens group is attached to a straight guide plate that can rotate relative to a cam ring, and this straight guide plate is guided in a straight guide groove to allow the camera of the lens group to move. A structure that restricts relative rotation with respect to the main body can be considered.

When the linear guide groove is provided in, for example, the fixed ring, it is desirable that the moving stroke of the linear guide plate for zooming be as large as possible in the optical axis direction. However, in order to realize this, if the fixed ring is linearly cut long in the optical axis direction, the strength of the component as a single unit will be impaired, and if the cutout is shortened, the strength will be satisfied but a sufficient movement stroke will be secured. Can't do it. Furthermore, if both strength and stroke are to be satisfied, the fixed ring becomes longer in the optical axis direction, making it difficult to make the camera compact.

[0004]

[The purpose of the device]

 According to the present invention, when the straight guide groove is provided in the fixed ring based on such a consciousness, it is possible to sufficiently secure the moving stroke of the straight guide plate without deteriorating the strength of the single component. The objective is to provide a straight-line guide mechanism for a zoom lens barrel.

[0005]

[Outline of the device]

 The present invention that achieves the above object is to provide a fixed ring to be fixed on the camera body side, a cam ring screwed to the inner circumference of the fixed ring, and a cam ring that can rotate relative to the cam ring in the optical axis direction. A linear guide plate that is movable along with the ring, a linear guide groove that linearly moves the linear guide plate in the optical axis direction, and the linear guide plate moves and guides in the optical axis direction. In a straight guide mechanism for a zoom lens barrel having a lens group that constitutes a fixed zoom lens, the straight guide groove is provided in the fixed ring along the optical axis direction, and one of the straight guide grooves is provided. It is characterized in that the portion is formed as a bottomed groove in which the radial bottom of the fixed ring is closed.

[0006]

[Example of device]

 The present invention will be described below with reference to illustrated embodiments. As shown in FIG. 1 and FIG. 2, a zoom lens barrel to which the present invention is applied is a movable lens group of three groups before and after a first lens group L1, a second lens group L2, and a third lens group L3. The zoom lens is designed to move along a predetermined locus in the optical axis direction for zooming, and the second group lens L2 is moved for focusing.

In the fixed block 50 (FIGS. 1, 5, and 6) fixed to the camera body 10, the fixing ring 12 is provided with engaging protrusions (rotational protrusions) that are provided at a plurality of locations on the outer periphery thereof so as to radially protrude. The dynamic control portions) 52 are engaged with the engaging recesses 51 provided at a plurality of locations on the inner circumference of the block 50, and the relative rotation with respect to the block 50 is regulated and fitted. The fixed ring 12 has a male helicoid 12c on the outer circumference, a female helicoid 12a on the inner circumference, and a first pinion 63, which is the final gear of the gear train G (FIG. 7), along the optical axis direction. The cam ring 13 is provided with a support portion 55 that bulges in the radial direction of the cam ring 13 and that rotatably supports the support portion 55.

The fixed ring 12 has a female helicoid 12 a on the inner periphery thereof screwed into a male helicoid 13 a on the outer periphery of the cam ring 13 to fit and support the cam ring 13. A spur gear 13b inclined in the lead direction of the male helicoid 13a is provided on the outer periphery of the rear end of the cam ring 13. The spur gear 13b meshes with the first pinion 63 that rotates at a fixed position (FIG. 7). The first pinion 63 is formed to have a length corresponding to the dimension of the spur gear 13b in the optical axis direction, and one end of the rotation support shaft 56 is supported by the support plate 54 (FIG. 8). Is rotatably supported, and the other end is rotatably fitted in a shaft hole 74a (FIG. 8) of a support portion 74 provided at the inner peripheral rear end of the fixing ring 12. As a result, the first pinion 63 is provided on the fixed ring 12 so as to be able to mesh with the spur gear 13b and its relative movement in the optical axis direction and the radial direction with respect to the fixed ring 12 is restricted.

As shown in FIG. 2, a female helicoid 13c for the first lens group and inner cam grooves 13d, 13e for the second and third lens groups are formed on the inner peripheral surface of the cam ring 13. ing. The inner cam grooves 13d and 13e are formed by cutting a part of the female helicoid 13c and are formed in plural at different circumferential positions.

As shown in FIG. 5, the fixed ring 12 is provided with a support portion 57 having two brackets 58 sandwiching the second pinion 60 from the front and rear in the optical axis direction, behind the support portion 55 on the outer periphery thereof. There is. The second pinion 60, which constitutes the gear train G and which directly transmits the driving force (rotational force of the motor 72) from the camera body side to the first pinion 63, has its rotation support shaft 61 mounted on the two brackets 58. The support holes 59 formed respectively are slidably penetrated. As a result, the second pinion 60 is restricted from moving relative to the fixed ring 12 in the optical axis direction by the two brackets 58, and protrudes into the support portion 55 from the opening 12d formed between the brackets 58 of the fixed ring 12. The pinion 63 is located on the fixed ring 12 side so as to mesh with the pinion 63.

The fixed ring 12 has linear guide grooves 80a, 80b at four positions in the circumferential direction thereof, which engage the radial projections 15a, 15b of the linear guide plate 15 with each other and guide them linearly. (Fig. 4). These linear guide grooves 80a and 80b are formed in the inner periphery of the fixed ring 12 at substantially equal intervals, and the linear guide grooves 80a are provided in a portion corresponding to the support portion 55 and the first pinion 63 is provided. It is formed so as to be wide in the circumferential direction of the fixed ring 12 sandwiching it. The straight guide grooves 80b are formed at three other positions in the circumferential direction of the fixed ring 12, and are formed narrower than the straight guide grooves 80a. The three linear guide grooves 80b are continuously formed from the lower end of the fixed ring 12 to a predetermined position above the fixed ring 12, as shown in FIG. The lower side of the straight guide groove 80b is configured as a bottomed groove in which the radial bottom of the fixed ring 12 is closed, and the upper side is configured such that the inner peripheral side and the outer peripheral side of the fixed ring 12 penetrate. Has been done. The bottom in the radial direction of the straight guide groove 80b, which is a bottomed groove, is formed by the inner surface of the engaging projection 52 formed by projecting on the outer peripheral side of the fixed ring 12.

As shown in FIGS. 1 and 2, a linear guide ring 14 is arranged on the inner peripheral side of the cam ring 13. An outer peripheral flange 14a, which should come into contact with the inner peripheral flange 13f of the cam ring 13, is formed at the rear end of the linear guide ring 14. At the rear end of the linear guide ring 14, the linear guide plate 15 sandwiching the inner peripheral flange 13f with the outer peripheral flange 14a so as to be relatively rotatable is fixed by a fixing screw 16. Therefore, the linear guide plate 15 is rotatable relative to the cam ring 13 and moves along with the cam ring 13 in the optical axis direction.

The linear guide plate 15 is located on the inner circumference of the fixed ring 12 in a state where the radial projections 15a and 15b are fitted in the linear guide grooves 80a and 80b, respectively, and are orthogonal to the optical axis direction. The radial protrusion 15a provided on the straight guide plate 15 is formed to have a wide width corresponding to the wide straight guide groove 80a and has a recess 15c at the center thereof so as to straddle the first pinion 63. It is constructed so that it can be located very close to the one pinion 63. Each of the three radial projections 15b of the linear guide plate 15 is formed as a simple projection corresponding to the narrow linear guide groove 80b.

A male helicoid 18a on the outer periphery of the first group lens support frame 18 to which the first group lens L1 is fixed is screwed to the female helicoid 13c of the cam ring 13. The leads of the female helicoid 13c and the male helicoid 18a are reversed from the leads of the female helicoid 12a and the male helicoid 13a. A cam pin 20 planted on the outer peripheral surface of the second group moving frame 19 is fitted in the inner cam groove 13d of the cam ring 13, and a third group lens L3 is fixed to the inner cam groove 13e. A cam pin 22 planted on the outer peripheral surface of the frame 21 is fitted. The cam pins 20 and 22 are slidably engaged with linear guide grooves 14c and 14d formed in the linear guide ring 14 in parallel with the optical axis O at different circumferential positions. As a result, the second and third lens groups L2 and L3 are guided straight to the straight guide ring 14. Therefore, the linear guide ring 14, that is, the second and third lens groups L2 and L3 are rotatable relative to the cam ring 13 and move together with the cam ring 13 in the optical axis direction.

The second group moving frame 19 is fixed to the rear of the AF / AE unit 24, and the second group lens moving frame 42 is fixed to the front. A male helicoid 25a provided on the outer circumference of the second group lens frame 25 to which the second group lens L2 is fixed is screwed into a female helicoid 24a provided on the inner circumference of the AF / AE unit 24. The AF / AE unit 24 has a drive pin 24b that is driven in the circumferential direction by an angle according to the subject distance information, and the drive pin 24b projects in the radial direction of the second group lens frame 25. 35 is engaged. Therefore, the second group lens frame 25, that is, the second group lens L2, advances and retreats in the optical axis direction according to the rotation angle of the drive pin 24b and the leads of the helicoids 24a and 25a, whereby focusing is performed. The AF / AE unit 24 also opens and closes the shutter blade 36 based on the brightness information of the subject.

On the inner peripheral side of the first group lens support frame 18, a straight advance key 18d to be fitted in the straight advance plan inner groove 14b formed on the outer surface of the straight advance ring 14 is formed, and the first group lens support frame 18 is formed. The (first lens group L1) is linearly guided by the linear guide ring 14 by fitting the linear key 18d into the linear guide groove 14b. A light blocking portion 40 is provided between the cylindrical portion 44 of the first group lens support frame 18 and the second group lens moving frame 42.

As shown in FIGS. 5 and 8, at a position corresponding to the support hole 59 of the fixed block 50, a rotary support shaft 61 to be slidably penetrated into the support hole 59 is provided in front of the optical axis. It is provided so as to project. The rotation support shaft 61 penetrates the second pinion 60 sandwiched between the two brackets 58 together with the two brackets 58 in a state where the fixed ring 12 is fitted to the fixed block 50. The relative movement of the second pinion 60 with respect to the fixed block 50 in the optical axis direction is allowed. The gears 65, 66, 67, 68, 69, 70 constituting the gear train G other than the first pinion 63 and the second pinion 60 are supported by the gear support member 62 shown in FIG. It is supported on the 50 side. Further, a positioning hole 73 is formed in a portion of the gear support member 62 which is close to the second pinion 60 so that the positioning small diameter portion 61a of the tip end portion of the rotary support shaft 61 is inserted therethrough.

The fixed ring 12 has a male helicoid 12 c on the outer periphery thereof screwed into a female helicoid 11 a on the inner periphery of the adjustment ring 11 to fit and support the adjustment ring 11. The adjusting ring 11 approaches the fixed ring 12 by rotating in one direction around the optical axis, and separates from the fixed ring 12 by rotating in the other direction. When the back focus amount is adjusted, the adjusting ring 11 is restricted in relative movement in the optical axis direction with respect to the fixed block 50, that is, the camera body 10 by the controlling means (not shown). The ring 11 is brought into contact with and separated from the ring 11 to change its position with respect to the camera body 10. The adjusting ring 11 also has a plurality of positioning teeth 78, and the fixed block 50 has a positioning plate 76 having locking teeth 76a at positions corresponding to the positioning teeth 78. The positioning plate 76 can be moved and fixed in the left-right direction in FIG. 7 by loosening or tightening the fixing screw 77. When the fixing screw 77 is fastened, the positioning teeth 78 are locked to adjust. The rotation of the ring 11 is restricted.

The camera having the above configuration operates as follows. From the shortest focal length state, when the first pinion 63 meshed with the spur gear 13b of the cam ring 13 is rotationally driven by the driving force of the motor 72 transmitted via the gear train G, the cam ring 13 is driven by the male helicoid 13a and the male helicoid 13a. According to the female helicoid 12a, it advances in front of the optical axis while rotating.

As a result, the first group lens support frame 18, which is guided straight by the straight guide ring 14, further advances with respect to the cam ring 13 in accordance with the relationship between the male helicoid 18a having the reverse lead and the female helicoid 13c. Similarly, the cam pins 20 and 22 of the second lens group moving frame 19 and the third lens group lens 21 which are linearly guided by the linear guide ring 14 are fitted in the inner cam grooves 13d and 13e of the cam ring 13, respectively. Therefore, as the cam ring 13 rotates, it follows the shapes of the inner cam grooves 13d and 13e, advances in the optical axis direction, and zooming is performed.

The second lens group moving frame 19 and the third lens group frame 21, that is, the second and third lens groups L 2 and L 3 are optically guided by a linear guide plate 15 connected through a linear guide ring 14. The fixed ring 12 that is guided to move in the axial direction and guides the linear guide plate 15 to move in the optical axis direction is configured such that a part of each of the linear guide grooves 80b at the three positions is formed as a bottomed groove. Sufficient strength is given as a simple substance. Further, since it is a bottomed groove, the straight-ahead guide groove 80b can be formed long in the optical axis direction so as to secure a sufficient movement stroke of the straight-ahead guide plate 15.

[0022]

[Effect of device]

 As described above, according to the present invention, the straight guide groove is provided in the fixed ring along the optical axis direction thereof, and a part of the straight guide groove is provided with the bottom of the fixed ring in the radial direction. Since the groove is formed, it is possible to provide the straight guide groove with respect to the fixed ring without impairing the strength of the component as a single component and while ensuring a sufficient movement stroke of the straight guide plate. As a result, the fixed ring itself does not need to be dimensioned in the optical axis direction, so that the fixed ring can be made short, which contributes to the compactness of the camera.

[Submission date] March 25, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007] The camera body 10 stationary block 50 fixed to (FIGS. 1, 5, 6) has a fitting portion 51, the inner surface 51b of the fitting portion 51, engaging a plurality of locations in the circumferential direction A mating recess 51a is formed. The fixed ring 12 has a plurality of engaging protrusions 52 corresponding to the engaging recesses 51a at a plurality of positions on the outer peripheral surface . The fixed ring 12 engages the engaging projections 52 at a plurality of positions with the engaging recesses 51a at a plurality of positions of the block 50, and the relative rotation with respect to the fixed block 50 is restricted and the relative movement in the optical axis direction is prevented. It is fitted in an allowed state. The fixed ring 12 has a male helicoid 12c on the outer circumference, a female helicoid 12a on the inner circumference, and a first pinion 63, which is the final gear of the gear train G (FIG. 7), along the optical axis direction. A supporting portion 55 for accommodating and rotatably supporting it is provided by bulging in the radial direction of the cam ring 13. In addition, 9 in FIGS . 1 and 5 is a light-shielding member provided on the inner circumference of the tip portion of the fixed ring 11.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

The fixed ring 12 has a female helicoid 12 a on the inner periphery thereof screwed into a male helicoid 13 a on the outer periphery of the cam ring 13 to fit and support the cam ring 13. A spur gear 13b inclined in the lead direction of the male helicoid 13a is provided on the outer periphery of the rear end of the cam ring 13. The spur gear 13b meshes with the first pinion 63 that rotates at a fixed position (FIG. 7). The first pinion 63 is formed long in the optical axis direction so as to correspond to the moving dimension of the spur gear 13b in the optical axis direction . The rotation shaft 5 of the Ichipi anion 63, one end, via a support plate 54 (FIG. 8) is rotatably supported by the support 5 5 and the other end, the inner periphery rear portion of the stationary ring 12 It is rotatably fitted in the shaft hole 74a (FIG. 8) of the support portion 74 provided in the. As a result, the first pinion 63 is provided on the fixed ring 12 so as to be able to mesh with the spur gear 13b and its relative movement in the optical axis direction and the radial direction relative to the fixed ring 12 is restricted.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

As shown in FIGS. 5 and 8 , the fixed ring 12 has a support portion 57 having two brackets 58 which sandwich the second pinion 60 from the front and rear in the optical axis direction, behind the support portion 55 on the outer periphery thereof. Is equipped with. The second pinion 60, which constitutes the gear train G and which directly transmits the driving force (rotational force of the motor 72) from the camera body side to the first pinion 63, has its rotation support shaft 61 mounted on the two brackets 58. The support holes 59 formed respectively are slidably penetrated. As a result, the second pinion 60 is restricted from moving relative to the fixed ring 12 in the optical axis direction by the two brackets 58, and protrudes into the support portion 55 from the opening 12d formed between the brackets 58 of the fixed ring 12. It is located on the fixed ring 12 side so as to mesh with the first pinion 63.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

As shown in FIGS. 5 and 8, at a position corresponding to the support hole 59 of the fixed block 50, a rotary support shaft 61 to be slidably penetrated into the support hole 59 is provided in front of the optical axis. It is provided so as to project. The rotation support shaft 61 penetrates the second pinion 60 sandwiched between the two brackets 58 together with the two brackets 58 in a state where the fixed ring 12 is fitted to the fixed block 50. The relative movement of the second pinion 60 with respect to the fixed block 50 in the optical axis direction is allowed. The gears 65, 66, 67, 68, 69, 70 constituting the gear train G other than the first pinion 63 and the second pinion 60 are supported by the gear support member 62 shown in FIG. It is supported on the 50 side. In that case, the gear 65 is located in the transmission immediately upstream of the second pinion on 60 is rotatably supported by the rotary shaft 56 projecting on the inner surface of the gear support member 62, the distal end portion of the rotary shaft 56 in this state The recessed portion 56a is engaged with the engagement pin 75 that is formed by projecting on the fixed block 50 corresponding to the gear 65 . The gear support member 62 is screwed to the fixed block 50. Further, a positioning hole 73 is formed in a portion of the gear support member 62 which is close to the second pinion 60 so that the positioning small diameter portion 61a of the tip end portion of the rotary support shaft 61 is inserted therethrough.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

The fixed ring 12 has a male helicoid 12 c on the outer periphery thereof screwed into a female helicoid 11 a on the inner periphery of the adjustment ring 11 to fit and support the adjustment ring 11. By rotating the adjustment ring 11 to one direction or the other direction, the stationary ring 12, relative to the fixed block 50 (the camera body 10), causes forward and backward in the optical axis direction together with the second pinion 60 (relative moving) be able to. Bar Tsu During adjustment of the click focus amount, by the tip 90b of the hook-shaped locking member 9 0 (restricting means), the adjustment while restricting relative movement in the optical axis direction of the adjustment ring 11 with respect to the fixed block 50, i.e. the camera body 10 since rotating the ring 11 in forward and reverse, the position in the optical axis direction with respect to the camera body 10 of the stationary ring 12, i.e. Ru can be changed the position of the optical axis direction for a film in the focal plane. Adjustment ring 11, that is formed with a plurality of positioning teeth 78 thereunder. Solid Teibu lock 50 is in a position corresponding to the said positioning teeth 78, and a positioning plate 76 having a locking tooth 76a. The positioning plate 76 can be moved and fixed in the left-right direction in FIG. 7 by loosening or tightening the fixing screw 77b . When the fixing screw 77 is fastened , the positioning teeth 78 are engaged by the locking teeth 76a. Then, the rotation of the adjusting ring 11 is restricted. Fixing screws 77a are remain loosened during normal, it is used only in the lateral direction of the guide of the positioning plate 76.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of a zoom lens barrel to which the present invention is applied.

FIG. 2 is an upper half longitudinal sectional view showing a schematic configuration of the zoom lens barrel with different sectional positions.

FIG. 3 is an enlarged perspective view showing a fixed ring of the zoom lens barrel.

FIG. 4 is a schematic view showing a relationship between a fixed ring of the zoom lens barrel and a straight guide plate as viewed from the camera body side.

FIG. 5 is an exploded perspective view showing a combined structure of the zoom lens barrel and a fixed block.

FIG. 6 is a perspective view showing a state in which the zoom lens barrel is supported by a fixed block.

FIG. 7 is a front view showing an assembly structure of a zoom lens barrel, a gear train, and the like with respect to a camera body.

FIG. 8 is a sectional view showing a coupling structure of a gear train that transmits rotation to a cam ring.

[Explanation of symbols]

 10 Camera Main Body 12 Fixed Ring 13 Cam Ring 15 Straight Guide Plate 15a 15b Radial Protrusion 52 Engagement Projection Part (Rotation Restriction Part) 80a 80b Straight Guide Groove L1 First Group Lens L2 Second Group Lens L3 Third Group Lens O optical axis

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[Procedure amendment]

[Submission date] March 25, 1994

[Procedure correction 6]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

Claims (3)

[Scope of utility model registration request] 1. A fixed ring to be fixed to the camera body side;
A cam ring screwed to the inner circumference of the fixed ring; a straight guide plate that can rotate relative to the cam ring and can move together with the cam ring in the optical axis direction; and guide the straight guide plate in the optical axis direction. A zoom lens barrel having a linear guide groove; and a lens group that constitutes a zoom lens that is guided to move in the optical axis direction by the linear guide plate and whose position in the optical axis direction is determined by a cam ring; A zoom lens characterized in that the fixed ring is provided along the optical axis direction, and a part of the straight guide groove is formed as a bottomed groove in which the radial bottom of the fixed ring is closed. Linear guide mechanism for lens barrel. 2. The engagement ring according to claim 1, further comprising an engagement protrusion that protrudes in the radial direction on the outer peripheral side of the fixed ring, and the bottom of the bottomed groove is the inner surface of the engagement protrusion. A linear guide mechanism for a zoom lens barrel. 3. The engaging protrusion according to claim 2,
A linear guide mechanism for the zoom lens barrel, which is configured as a rotation restricting portion with respect to the camera body side.