JPS6367172B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a camera body and a lens barrel that is detachably attached to the camera body. The present invention relates to an autofocus camera that is driven to perform focus adjustment.

Prior Art For example, in a single-lens reflex camera with interchangeable lenses that performs autofocus using TTL distance measurement, the camera body includes an autofocus drive member and its control unit, and the interchangeable lens barrel includes the drive member. A driven member is provided which is coupled to perform an autofocus operation. The mounting positions of the camera body and the interchangeable lens barrel are regulated by engagement between the body-side locking part and the barrel-side locked part provided on their mounts, and the driving member and the driven member are connected to each other. should always correspond correctly to ensure proper connection and transmission.

However, because the mount has some play in the fit, even if the lock is secured, the body and lens barrel will be eccentric around the lock.
The connection portion between the driving member and the driven member is displaced accordingly. This positional shift reduces the drive efficiency for the driven member, which increases the time required for autofocus and increases power consumption. Furthermore, the autofocus function becomes even more uncertain depending on the degree of play in the mount fitting and the type of transmission from the driving member to the driven member.

Since such a problem occurs after the mount is fully mounted, it cannot be solved by the means known in U.S. Pat. No. 4,130,358, which detects the degree of fitting of the mount. Nothing that can solve this problem has yet been provided.

OBJECT OF THE INVENTION It is an object of the present invention to provide an autofocus camera that can solve the above-mentioned problems.

Features of the Invention The present invention is an autofocus camera consisting of a camera body and a lens barrel, in which a drive-side engaging portion provided on the camera body is located within or near a mount position regulating portion provided on a detachable mount. It was established.

Example To explain the example, this example describes a camera body, which is a main optical device, as an example in which two components of an optical device are detachably connected and a driving force is transmitted from one of the components to the other. An example is shown in which an autofocus drive is transmitted when the lens is coupled to an interchangeable lens, which is an interchangeable optical system device. FIGS. 1 to 8 show an example in which the driving member on the camera body side and the driven member on the interchangeable lens side are connected and disconnected at the mount positioning position of the camera body and the interchangeable lens, that is, at the mount lock part. show. FIG. 1 is a front view of the camera body 1, in which a body-side removable mount 3 is constructed in the center of a front cover 4 that protrudes from the front of the body 1. 7 is a positioning member release button. Reference numeral 10 denotes a tip positioning portion of a mount positioning member 9, which will be described later. The positioning portion 10 is inserted into a through hole formed in the detachable mount 3 from the inside, and a spring 8 (described later) is inserted in a direction protruding from the mount surface at all times. ) is energized. Reference numeral 13 denotes a drive shaft as a drive member provided on the body 1 side, and this is referred to as a first drive shaft. First drive shaft 13
is a cylindrical mount positioning member 9
It is held so that it can move forward and backward with a small amount of swing within its inner diameter. The reason for this is to absorb misalignment of the axis with a second vibration axis 60 on the side of the interchangeable lens 2, which will be described later, due to dimensional errors of parts, mounting errors between the camera body and the interchangeable lens, etc.

In FIG. 1, the tip of the first drive shaft 13 is visible, and an engaging pawl 17 (the reference numeral is omitted in the drawing), which will be described later, is further formed on the tip surface.

FIG. 2 is a simplified diagram showing the motor 22 and transmission gear train within the camera body 1. That is, for example, the motor 22 is disposed below the mirror 30, and the rotation thereof is transmitted to the gear 21 via the intermediate gear train 31 and the like, and further transmitted to the gear 19 fixed to the first drive shaft 13. 1 drive shaft 13 is rotated at a constant speed.

FIG. 3 is a view of the interchangeable lens 2 seen from the back side, that is, the side where it is attached to the camera body 1, and 54 is a lens-side detachable mount that is mounted on the detachable mount 3 on the camera body 1 side. Reference numeral 53 denotes a rear lens group installed inside. Reference numeral 64 denotes a mount positioning recess configured as a notch that opens to the outer periphery in a part of the flange forming the mounting surface of the detachable mount 54, and the mount positioning member 9 on the camera body 1 side is connected to the recess 64.
When the positioning part 10 is inserted, both are locked at that position. A second drive shaft 60 is inserted into the through hole in the mount positioning recess 64 and has its tip facing the surface of the detachable mount 54, and is a driven member with respect to the first drive shaft 13.

FIG. 4 is a simplified diagram showing a transmission gear train inside the interchangeable lens 2. FIG. That is, a gear 66 fixed to the recoid tube 58, which will be described later, advances and retreats an inner tube 59, which will be described later, in which a lens group is fixed, in the optical axis direction;
Gear 6 fixed to second drive shaft 60 and rotating together
5 are interlocked.

Figure 5 shows the camera body 1 explained above.
and interchangeable lens 2 are completely combined, and both drive shafts 1
3 and 60 are connected, and a protruding pin 63 formed in an engagement recess 62 at the tip of the second drive shaft 60 is connected to the engagement hole 18 formed in the engagement claw 17 at the tip of the first drive shaft 13. The state is shown in which the shafts are engaged and the axes are aligned, and the circuit switches from the motor 22 and motor drive control circuit 32 sides are turned on.

In FIG. 5, the interchangeable lens 2 side is indicated by a code in the 50s or higher, and 52 is the front lens group;
3 is a rear lens group. These lens groups 52,
53 is fixed within the inner cylinder 59. Reference numeral 56 denotes an outer barrel of an interchangeable lens, and a second shaft, which is a driven shaft relative to the camera body 1 side, is connected between the outer barrel 56 and the inner barrel 59.
A drive shaft 60 and a lens feeding mechanism are provided. A bearing 61 is fixed to the outer cylinder 56, and one end of the second drive shaft 60 is supported by the bearing 61. A gear 65 is fixed to the second drive shaft 60, and the gear 65 meshes with a gear 66 fixed to the inner helicoid cylinder 58. 55 is an outer recoid tube. The outer recoid cylinder 55 is fixed to the removable mount 54. (See Figure 7) 57 is an aperture ring that is rotatable. The outer recoid tube 55, the inner helicoid tube 58, and the inner tube 59, and the linear key and key groove (none of which are shown) formed therein, allow
The lens is extended in a straight line by the rotational force of the gear 65.

Reference numeral 51 denotes the optical axis of the lens, and a second drive shaft 60 arranged parallel to the optical axis 51 has its tip protruding from the through hole of the detachable mount 54 into the mount positioning recess 64. . An engagement recess 62 is formed on the end face of this tip, and corresponds to the engagement claw 17 of the first drive shaft 13 on the camera body 1 side.
Both 62 and 17 constitute a dog clutch.
Furthermore, a second drive shaft 6 is provided in the engagement recess 62.
A protruding pin 63 is formed to coincide with the axis of 0. This protruding pin 63 forms a pair with the engagement hole 18 formed in the engagement claw 17 of the first drive shaft 13. In the explanation of the embodiment, the gear 65 directly rotates the gear 66, but if it is necessary to change the gear ratio depending on the characteristics of each interchangeable lens, an intermediate gear train may be used. Things are also easy.

Next, to explain the camera body 1 side, the removable mount 3 on the camera body 1 side, on which the interchangeable lens 2 is mounted, has a bayonet spring 6 on the back side, which ensures a loose connection when the interchangeable lens 2 is attached. There is. The positioning member release button 7, which partially projects from the front cover 4, is loosely fitted between the front cover 4 and the front base plate 5, and is always urged by a spring 8 in the direction of protrusion from the front cover 4. 23 is an engagement plate fixed to the positioning member release button 7, and the engagement plate 23 is engaged with the circumferential groove of the mount positioning member 9. Therefore, the positioning member release button 7 and the mount positioning member 9 are integrated. will be moved to. The mount positioning member 9 is formed in a cylindrical shape,
The distal end positioning portion 10 is fitted into the through hole of the body side removable mount 3, and the rear end portion is fitted onto the outer periphery of the bearing member 12 of the first drive shaft 13, so that it is held movably forward and backward. There is. The bearing member 12 is attached to a hole in the front base plate 5. Reference numeral 14 denotes a movable collar, which is slidably fitted onto the first drive shaft 13 and is always biased to the left in the figure by a spring 15. 33 is a collar fixed to the first drive shaft 13, and the movable collar 1 is attached to the collar 33.
4 press against each other, the force of the spring 15 urges the first drive shaft 13 to the left in the figure. In this case, the movable flange 14 pushes the fixed flange 33 to the left in the figure, but at the end of its stroke, the movable flange 14 pushes the second inner diameter enlarged step 34 of the mount positioning member 9.
4 come into contact with each other, and as a result, the contact pressure on the fixed collar 33 is released, so the first drive shaft 13 can rotate smoothly without being subjected to pressure from the spring 15. Regarding the relative positional relationship of the first drive shaft 13 with respect to the mount positioning member 9, the position where the fixed collar 33 of the first drive shaft 13 abuts the first inner diameter enlarged step portion 38 of the mount positioning member 9 is the most It will be to the left.

An engaging pawl 17 is formed at the tip of the first drive shaft 13 . The engagement claw 17 is fitted into the engagement recess 62 of the second drive shaft 60 on the side of the interchangeable lens 2.
It is formed to protrude from the end face. Furthermore, an engagement hole 18 is formed from the distal end surface of the engagement claw 17 in alignment with the axis of the first drive shaft 13 . The insertion hole 18 receives the protruding pin 63 of the second drive shaft 60 to accurately align the axes of the first drive shaft 13 and the second drive shaft 60.

35 is a drive circuit for driving the first drive shaft 13, which includes the motor 22 and the motor drive control circuit 3;
2. Switch 36, fixed electrode 27 and movable electrode 26
This is a unique switch consisting of, etc. The switch 36 is turned on and off in conjunction with, for example, a shutter release (not shown). When the switch 36 is turned on while the fixed electrode 27 and the movable electrode 26 are in contact with each other, the entire drive circuit 35 is turned on and the motor is driven. Reference numeral 37 denotes a distance measuring circuit which uses the power supply in the driving circuit 35 as a common power source, and the distance measuring circuit 37 is operated by a switch consisting of the movable electrode 26 and another fixed electrode 37a which can be slidably contacted thereto. The structure is such that it is controlled. The second fixed electrode 37a is formed to have a slightly wider width than the first fixed electrode 27, but this is so that only the distance measuring circuit 37 can be turned on even when the drive circuit 35 is off. This is a consideration for the purpose of doing so. That is, if the camera has a mechanism to display in-focus and out-of-focus states (e.g. in the viewfinder), an interchangeable lens without an autofocus arrangement (manual Even when a normal lens capable of focusing only is attached to the camera, if the distance measuring circuit 37 is activated, there is an advantage that the focusing operation can be easily performed using the display mechanism. The reason why the second fixed electrode 37a is formed to be slightly wider is to operate only the distance measuring circuit 37 for this purpose. In this case, the movable electrode 26
In order to make the lens contact only the fixed electrode 37a, the depth of the positioning recess (64 in FIG. 5) for locking in the ordinary interchangeable lens is different from that of the interchangeable lens equipped with an autofocus mechanism (64 in FIG. 5). Needless to say, it is necessary to form it slightly deeper than the one shown in the figure.

Note that if an interchangeable lens whose distance measurement performance is not guaranteed by the distance measurement circuit 37 is attached, such as a super telephoto lens, there is a risk that inaccurate distance measurement will be performed and the distance measurement result will be displayed. Therefore, in the case of a lens whose ranging performance is not guaranteed, for example, a protrusion is formed in the positioning recess and the movable electrode 26 is connected to the two fixed electrodes via the first drive shaft 13. What is necessary is just to configure it so that it swings off so as not to come into contact with either 27 or 37a.
The distance measuring circuit 37 inputs the focusing information of the subject to the motor drive control circuit 32, and the motor drive control circuit 32 controls and drives the motor 22 in terms of rotation direction, rotation speed, etc. The rotation of the motor 22 is transmitted to the gear 21 provided on the front base plate 5 via the intermediate gear train 31 (see FIG. 2), and further transmitted to the gear 19 fixed to the first drive shaft 13. As a result, the first drive shaft 13 is rotated by the required amount. 2
0 is the shaft of the gear 21, which is fixed to the front base plate 5. Reference numeral 27 denotes a fixed electrode provided at one end of the drive circuit 35, and a switch lever 24 that can swing about the fulcrum 25 with respect to the fixed electrode 27 is provided. The other end of the switch lever 24 is engaged with an annular groove 16 provided at the rear end of the first drive shaft 13. Therefore, the switch lever 24 is swung as the first drive shaft 13 moves back and forth, and the movable electrode 26 at the tip of the switch lever 24 comes into contact with the fixed electrode 27 at an appropriate swiveling position. The other end of the circuit 35 is connected to the switch lever 24 . The fixed electrode 27 and the movable electrode 26 are connected to each other by fitting the mount positioning member 9 into the mount positioning recess 64, regardless of whether or not there is a clutch connection between the engaging claw 17 and the engaging recess 62. (See Figure 5).
On the other hand, the mounting between camera body 1 and interchangeable lens 2 is not completed (see Figures 6 and 7).
In this case, the movable electrode 26 and the fixed electrode 27 are located at separate positions.

Next, to explain the operation, the interchangeable lens 2 is pressed against the camera body 1 in the state shown in FIG. 6 against the pressure of the springs 8 and 15 (see FIG. 7).
When the interchangeable lens 2 is rotated, the interchangeable lens 2 reaches the position of the mount positioning member 9 of the camera body 1.
When the mount positioning recess 64 has come around, the positioning part 10 of the mount positioning member 9 automatically enters the positioning recess 64 due to the pressure of the springs 8 and 15 (see FIG. 8), and the interchangeable lens 2 is It is locked in a predetermined position relative to the camera body 1. At this point, the movable electrode 26 comes into contact with the fixed electrode 27 and enters the switch-on state.

On the other hand, at this point, the engagement pawl 17 of the first drive shaft 13 and the engagement recess 62 of the second drive shaft 60 are not necessarily engaged. FIG. 8 shows such a situation. In this state, the first drive shaft 13 can be retracted to the right in the drawing relative to the mount positioning member 9 against the pressure of the spring 15 while ensuring engagement between the mount positioning member 9 and the mount positioning recess 64.

As will be described later, when the motor 22 starts rotating, the first drive shaft 13 also starts rotating, and the moment the engagement claw 17 and the engagement recess 62 align, the spring 15 automatically engages the engagement recess 62. left in a bad state,
The driving force is transmitted to the interchangeable lens side (state shown in FIG. 5). Of course, the insertion hole 18 and the protruding pin 63
The shafts 13 and 60 also fit together, and the axes of both shafts 13 and 60 coincide.

Now, in FIG. 5, close the switch 36,
When the signal from the ranging circuit 37 is input to the motor drive control circuit, the motor 22 rotates, and the first drive shaft 13 rotates via the intermediate gear train 31 and gears 21 and 19. The rotation of the first drive shaft 13 is transmitted to the second drive shaft 60 via the clutches 17 and 62. Then, the helicoid tube 58 is further rotated through the gears 65 and 66. In response to this rotation, the optical systems 52 and 53 move in the direction of the optical axis 51. After the optical systems 52 and 53 are moved by the front focus and rear focus signals from the distance measurement circuit 37, the motor 22 is stopped by the focus detection of the distance measurement circuit 37, and the optical systems 52, 53 are moved.
53 also stands still and the automatic focusing operation is completed. When removing the interchangeable lens 2, the mount positioning member 9 is moved back by pressing the positioning member release button 7, and at that time, the first inner diameter enlarged step portion 38 of the member 9 is
As a result, the first drive shaft 13 also moves back together, and the clutches 17, 62 are disengaged. Therefore, by rotating the interchangeable lens 2 in the opposite direction, the interchangeable lens 2 can be removed.

In the above embodiment, the mount positioning position of the camera body 1 and the interchangeable lens 2, that is, the mount lock position, the drive member (first drive shaft 13) of the camera body 1, and the driven member (second drive shaft 13) on the interchangeable lens 2 side are explained. An example is shown in which the connection/disconnection position with the shaft 60) is arranged concentrically at the same position. On the other hand, the ninth
In the embodiment shown in FIGS. 1 and 10, the connection/disconnection position between the driving member and the driven member is not located at the same position as the mount lock position, but is provided in the vicinity of the mount lock position.

Similar to FIG. 3, FIG. 9 is a view of the interchangeable lens 2 seen from the back side, and 54 is a detachable mount.
Reference numeral 64 denotes a mount positioning recess which is a locked part for attaching the interchangeable lens 2, and the second drive shaft 60 is provided at a position having a slight rotation angle (approximately 30 degrees in this embodiment) with respect to the recess 64. ing. 62 is an engagement recess formed at the tip of the second drive shaft 60. Similar to FIG. 4, FIG. 10 is a simplified diagram showing the transmission gear train inside the interchangeable lens 2. As shown in FIG. 65 is the second
66 is the gear of the drive shaft 60, and the inner helicoid cylinder 58
It is a fixed gear. In the example shown in FIGS. 9 and 10, the second drive shaft 60 is not provided concentrically within the mount positioning recess 64, but in the vicinity thereof, compared to the example shown in FIGS. 1 to 8. The only difference is that it is provided in , and the rest are exactly the same. The position near the mount lock position is the mount lock position (for the interchangeable lens 2, the mount positioning recess 6
4). Therefore, this also includes cases where the drive force connection/disconnection position (in the case of the interchangeable lens 2, the tip of the second drive shaft 60) is located inside or outside of the locked position (the recess 64).
The relationship between the mount lock position and the drive force disconnection position is largely related to the misalignment between the axes of the drive shaft and the driven shaft connected thereto, with regard to drive force transmission. This will be explained with reference to FIG. 11. In FIG. 11, the detachable mount 54 of the interchangeable lens 2 is attached to the camera body 1.
The solid line shows the state where there is no mounting play, and the one-dot chain line and the two-dot chain line show the state where the interchangeable lens 2 is shifted upward by Δθ in the drawing due to the mounting play. It shows a state in which it is shifted downward by Δθ. Reference numeral 60 denotes a second drive shaft provided at position A near the mount positioning recess 64 (a position that is a little further away than in the case of FIG. 9 and has a rotation angle of about 45 degrees with respect to the recess 64). On the other hand, for comparison, an example in which the second drive shaft is provided at a position B far away from the mount positioning recess 64 is shown with reference numeral 70. 54a indicates the outer diameter of the detachable mount on the side of the interchangeable lens 2. Further, 3a indicates the inner diameter of the detachable mount on the body 1 side.

Now, let the mounting play of interchangeable lens 2 be 2・Δθ,
When the interchangeable lens 2 is shifted upward or downward by Δθ from the proper position, the fixing point of the interchangeable lens 2 is the mount positioning recess 6 which is the locked part with respect to the camera body 1.
4, the rotation angle Δθ shifts vertically from the proper position (solid line) about the recess 64. Said code 7
In the case of the comparative second drive shaft indicated by 0, this deviation causes a distance ΔlB deviation in the circumferential direction centering on the optical axis 51. On the other hand, in the case of the second drive shaft 60 provided near the mount positioning recess 64, the deviation around the optical axis 51 due to the same deviation angle Δθ is ΔlA.
That is, the difference between ΔlA and ΔlB is obvious even from the drawing.

In the above embodiment, for the sake of transmission efficiency, the driving member and the driven member are connected by the engagement of the linear groove 62 and the protrusion 17 on their abutting end faces, and this is done properly. Even if the groove 62 and the protrusion 17 are in the intersecting direction, they are not actually engaged. The driving of the driving member is started to align the directions of the groove and the protrusion.

Effect: Since the driving engagement portion of the camera body of the driven member is provided within or near the lock portion for regulating the mount position provided on the camera body, due to play in the mount fitting, the lock portion may be Even if the replacement optical system equipment is decentered with respect to the main body optical device, there will be no or a small amount of positional deviation between the driven connection and the drive connection in the main body optical device, and the drive member and the driven member will be properly connected, and the driven member will be properly connected. There is no reduction in drive efficiency or drive uncertainty.

[Brief explanation of drawings]

FIG. 1 is a front view of a camera body according to an embodiment;
FIG. 2 is a simplified diagram showing the transmission mechanism configured inside the camera body according to the embodiment, FIG. 3 is a back view of the interchangeable lens according to the embodiment, and FIG. 4 is a diagram showing the transmission mechanism configured inside the interchangeable lens. A simplified diagram showing the mechanism; FIG. 5 is a vertical cross-sectional view with an interchangeable lens attached to the camera body; FIGS. 6 to 8 are vertical cross-sectional views showing the process of attaching the interchangeable lens; FIGS. 9 and 10. The figure shows an example in which the driven coupling part of the driven member is provided near the locked part for regulating the mount position, Figure 9 is a back view of the interchangeable lens, and Figure 10 shows the transmission mechanism configured inside the interchangeable lens. The simplified diagram shown in FIG. 11 is a diagram showing a comparison of axial misalignment of the transmission shaft when the driven coupling portion is provided near the locked portion and when it is provided far away from the locked portion. 1... Camera body, 2... Interchangeable lens, 7... Positioning member release button, 9... Mount positioning member, 1
3...first drive shaft, 17...engaging claw, 18...engaging hole,
60...Second drive shaft, 62...Engagement recess, 63...Protrusion pin, 64...Mount positioning recess.

Claims (1)

[Claims] 1. In an autofocus camera consisting of a camera body and a lens barrel that is detachable from the camera body, the camera body includes: a focus detection device; and a focus detection device that operates according to the focus detection state of the focus detection device. a drive shaft connected to and driven by the drive device; a body-side mount portion for mounting the lens barrel on the camera body; and a drive shaft provided on the body-side mount portion to which the lens barrel is mounted. and a body-side position regulating part that determines the mounting position when the camera is mounted, and the lens barrel includes: a photographing lens that adjusts focus by operating in the optical axis direction; A driven device to be actuated; a driven shaft connected to the driven device to actuate it; and a lens-side mount portion provided to face the body-side mount portion when the lens barrel is attached to the camera body. and a lens-side position regulating section provided on the lens-side mount section and cooperating with the body-side position regulating section to determine the mounting position, and the driving shaft and the driven shaft are engaged with each other to thereby engage with each other. The drive shaft side meshing portion is supported with a minute amount of runout, and is installed near the body side position regulating portion. Autofocus camera.