JPS6367171B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field One and the other of optical devices that are attached to and detached from each other,
The present invention relates to a driving force transmission device for an optical device with an exchangeable optical system, which includes a driving member and a driven member that connect and disconnect as they are attached and detached.

Conventional technology For example, in a single-lens reflex camera with interchangeable lenses that performs autofocus using TTL distance measurement, the camera body has an autofocus drive unit and its control system, and the interchangeable lens has an autofocus drive unit and its control system. A driven portion is provided, and the driving portion and the driven portion are connected and disconnected as the interchangeable lens is attached to and removed from the camera body. Various such driving force transmission devices are known, but none are yet fully satisfactory. By the way, to give an example, the one disclosed in Japanese Patent Application Laid-Open No. 55-95933 has a driving shaft and a driven shaft that have rotational axes perpendicular to the optical axis arranged in parallel, and the driving force is transmitted between them. Because of this, a large lateral pressure acts on both shafts, resulting in large friction loss, as well as excessive wear and seizure, which is unfavorable in terms of durability, and also causes noise generation. Furthermore, the driving force transmission mechanism is bulky and occupies a large space.

Furthermore, in the device disclosed in Japanese Patent Application Laid-Open No. 55-144214, the driving force is transmitted using a large-diameter ring that rotates around the optical axis. In addition to reducing the responsiveness to reach a stop, it also consumes a large amount of energy and reduces transmission efficiency. Furthermore, it is not suitable for optical systems such as two-component zoom lenses in which the lens retracts to the inside of the mount. In addition, Mikiaki
56-3684, in order to transmit the driving force between the drive shaft and the driven shaft, which are parallel to each other, both axes are arranged parallel to the optical axis, unlike the first conventional example. However, although the problem of lateral pressure in the first conventional example is not related to the mounting direction, the other drawbacks are almost the same.

Purpose of the Invention The present invention eliminates the drawbacks of the above-mentioned conventional examples, and provides a driving force transmission device for optical equipment that occupies a small space, is less prone to unnecessary pressure and wear during connection/disconnection, and has less reduction in transmission efficiency. With the goal.

Features of the Invention The present invention provides an optical instrument with an exchangeable optical system, in which an optical instrument component including a driving member and another optical instrument component including a driven member to be connected to the driving member are attached and detached, The driving part and the driven shaft are arranged so that their rotational axes are on the same axis parallel to the optical axis, and the driving force is transmitted by the mutual meshing engagement of the abutting end surfaces that are butted on the same axis. It's something I wanted to do.

Example To explain the example, this example is an example in which two components of an optical device are detachably coupled and a driving force is transmitted from one of the components to the other. An example in which drive for autofocus is transmitted is shown below. 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. The first drive shaft 13 has a small amount of deflection relative to the inner diameter of the positioning portion 10 (mount positioning member 9). The reason for this is to absorb misalignment of the axis with the second drive shaft 60 on the side of the interchangeable lens 2, which will be described later, due to dimensional errors of parts, adhesion errors between the camera body and the interchangeable lens, etc. In FIG. 1, the tip of the first drive shaft 13 is visible.
An engaging pawl 17 (the reference numeral is omitted in the drawings), which will be described later, is further formed on the distal end 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 rotation axis is completely aligned on the same axis parallel to the optical axis 51, and the motor 22 and motor drive control circuit 3
The circuit switch from the second side is in the on state.

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 tube 58. 55 is an outer recoid tube. The outer recoid tube 55 is fixed to the removable mount 54 (see FIG. 7), and 57 is an aperture ring that is rotatable relative to the removable mount 54. Through the outer recoid tube 55, the inner helicoid tube 58, the inner tube 59, and the linear keys and key grooves (none of which are shown) formed therein, the lens moves straight by receiving the rotational force of the gear 65. Unrolling is performed.

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 on the same axis parallel to the optical axis 51. Further, a protruding pin 63 is formed in the engagement recess 62 so as to coincide with the axis of the second drive shaft 60 . This protruding pin 63 forms a pair with the engagement hole 18 formed in the engagement claw 17 of the first drive shaft 13.

Next, explaining 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 surface, which ensures a loose connection when the interchangeable lens 2 is coupled. . 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. The insertion hole 18 and the protruding pin 63 assist in positioning.

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
It consists of one switch, 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. The distance measuring circuit 37 inputs the focusing information of the object to the motor drive control circuit 32, and the motor drive control circuit 32 thereby controls and drives the motor 22, such as the rotation direction and rotation speed. The rotation of the motor 22 is caused by the intermediate gear train 31.
(see FIG. 2) etc., to the gear 21 provided on the front base plate 5, and further to the first drive shaft 13.
The signal is transmitted to the gear 19 which is fixed to the position. This allows the first
The drive shaft 13 is rotated the required amount. 20 is gear 21
It is fixed to the front base plate 15 by the shaft. 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.
7 and the engagement recess 62 (see FIGS. 8 and 5). On the other hand, in a state where the mounting of the camera body 1 and the interchangeable lens 2 is not completed (see FIGS. 6 and 7), the movable electrode 26 and the fixed electrode 27 are located apart from each other. Note that in the circuit 35, the movable electrode 26
It was the motor drive control circuit 32 that opened and closed the fixed electrode 27, but as shown by the imaginary line, the distance measuring circuit 37 was opened and closed by connecting the fixed electrode 27 to the distance measuring circuit 37. You can do it like this.

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 embodiments described above, for the sake of transmission efficiency, the driving member and the driven member are connected by the engagement between the linear groove 62 and the protrusion 17 on their abutted end faces, and the connection is properly made. Even if the groove 62 and the protrusion 17 are in the crossing direction, they are not actually engaged, and in order to actually make the connection, the driving member The driving of the groove is started to align the direction of the groove and the protrusion.

Effects According to the present invention, in an optical system exchangeable optical device, in which one and the other of optical devices that are attached to and detached from each other are provided with a driving member and a driven member that connect and disconnect as they are attached and detached, the drive shaft and the driven shaft are connected to each other. The end faces of the two are engaged with each other so that their axes are on the same axis parallel to the optical axis. The space required for the driving force transmission mechanism is extremely small. Of course, even if the driving shaft and the driven shaft are arranged parallel to each other, even if they are parallel to the optical axis, there is a particular advantage in terms of space.
In addition, in a device in which a driving shaft and a driven shaft are arranged parallel to each other to transmit driving force, lateral pressure is applied between them, but in the present invention, such lateral pressure does not act, and therefore, the transmission mechanism is based on friction. Failures and reductions in transmission efficiency can be prevented, a driving force transmission device that consumes less energy and has good transmission efficiency can be achieved, and a device that does not generate noise and has favorable durability can be achieved.

[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 longitudinal sectional view showing the interchangeable lens attached to the camera body, and FIGS. 6 to 8 are longitudinal sectional views showing the process of attaching the interchangeable lens. 1... Camera body, 2... Interchangeable lens, 7... Positioning member release button, 9... Mount positioning member, 1
3... First drive shaft, 17... Locking claw, 18... Engagement hole,
32...Motor drive control circuit, 37...Distance measurement circuit,
60...Second drive shaft, 62...Engagement recess, 63...Protrusion pin, 64...Mount positioning recess.

Claims (1)

[Claims] 1. A lens-interchangeable automatic camera body comprising a camera body with a built-in driving device, and a lens barrel that is detachably attached to the camera body and has a built-in driven device. In the focus camera, a rotation transmission shaft on the camera body side connected to the driving device and arranged parallel to the photographing optical axis; and a rotation transmission shaft connected to the driven device and arranged parallel to the photographing optical axis. When the rotation transmission shaft on the lens barrel side and the above lens barrel are attached to the camera body,
A butting end face provided between the two transmission shafts so as to abut on substantially the same axis and engage with each other, and a butting end face provided on the camera body side, when the camera body and lens barrel are in a normal mounting position. , a positioning member that fits into a fitting recess provided on the lens barrel side, and a rotation transmission shaft on the camera body side that connects the positioning member and the rotation transmission shaft of the camera body side according to the movement of the positioning member. 1. A driving force transmission device for an optical instrument, comprising an interlocking member that moves a transmission shaft parallel to a photographing optical axis and connects abutting end surfaces.