JPS6118908A - Positioning device - Google Patents

Abstract

PURPOSE:To obtain the inexpensive, reliable positioning device of simple constitution by driving detectors which control the range of rotation of a cam cylinder in interlocking relation with a moving body by a detector driving means which operates associatively with the cam cylinder. CONSTITUTION:A rack gear 27 as the detector driving means is driven reciprocally in association with the rotation of the cam cylinder 7 in interlocking relation with the moving body which moves axially. A cam 27c which has right and left cam surfaces 27a and 27b are formed on the outside surface of the rack gear 27, and the detectors 21 and 22, such as microswitches, which control the rotation range of the cam cylinder 7 are driven by the cam surfaces 27a and 27b. When the detector 21 or 22 changes in state, the circuit connected to input terminals 12a and 12b of a driving motor 12 which drives the cam cylinder 7 enters an open state, thereby stopping driving the motor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a positioning device, and more particularly to a positioning device for an object that rotates forward and reverse.

[Prior Art] For example, in a zoom lens or the like, the lens barrel is rotated forward or backward to reduce or enlarge an image.

The structure of a conventional zoom lens mechanism is shown in FIGS. 1 to 5.

In the figure, the reference numeral 1 indicates a fixed lens on the front side, and the reference numeral 2 indicates a movable lens on the rear side. Although not shown, each lens is composed of a plurality of lenses.

The fixed lens l is fixed to a fixed lens barrel 4, and the movable lens 2 is fixed to a movable lens barrel 3.

A roller 5 is rotatably imaged on the movable lens barrel 3 via a screw 6, and this roller 5 is inserted into a curved cam hole 8 formed in the fixed lens barrel 4 as shown in FIG. It is fitted in a slidable manner, and is also fitted in a cam hole 9 formed linearly in a straight-moving cam cylinder 7 that is slidably fitted on the outside of the fixed lens barrel 4 .

Further, a gear portion 7a is formed at the end of the cam cylinder 7.

In addition, a stopper IO is fixed to the fixed lens barrel 4,
This stopper lO is IK-fitted to the 1n drive gear 1 in an elongated hole 11 formed along the circumferential direction of the cam cylinder 7, and can be moved freely within the corner l^ where the elongated hole 11 is formed. Can be moved.

When the cam cylinder 7 is rotated in the direction of the arrow A in FIG. 2 under the configuration described in -1- below, the roller 5, which is IK-aligned with the cam holes 8 and 9, is guided by these forces 1 and the holes. Then, the movable lens barrel 3 is moved in the direction of arrow B, that is, in the optical axis direction.

As a result, the distance between the fixed 1/lens 1 and the movable lens 2 changes, and the magnification of the lens as a whole changes.

Incidentally, the relationship between the cam holes 8, 9 and the elongated hole 11 is schematically shown in FIG.

As is clear from FIG. 3, when the cam cylinder 7 continues to rotate, the stopper 10 hits one end of the elongated hole 11, and is no longer able to rotate.

At this time, the roller 5 guided by the cam holes 8 and 9 does not reach both ends of these cam holes 8 and 9.

This structure is adopted because the spatial distance between the fixed and movable lenses 1.2 determines the performance of the lens, force 1, hole 8,
9 and the roller 5, the cam cylinder 7
This is to prevent excessive external force from being applied to the guide roller 5 and deteriorating the performance of the lens even if the guide roller 5 rotates more than necessary.

- The movement of the movable lens 2 is determined by the shape of the curved cam hole 8 formed in the fixed chain portion 4.

For example, when only two types of 1/lens magnification are required, the cam hole 8 can be composed of three straight sections, straight grooves 8a, 8c, and an oblique groove 8b, as shown in FIG. , since the straight grooves 8a and 8c are each in a plane perpendicular to the optical axis, where in the straight grooves 8a and 8c is the roller 5 placed?
The lens spacing remains constant even when the lens is closed.

A zoom lens with such a structure is specifically a fourth lens.
It is driven by a drive device equipped with a slip mechanism as shown in FIGS.

The fixed lens barrel 4 side constituting the zoom lens is fixed to a support member 15 as shown in FIG. A bent portion 15a is formed at one end of the support member 15, and a drive motor 12 made of a DC motor or the like is fixed to the bent portion 15a side.

A slip mechanism 14 is provided on the output shaft 13 of this drive motor 12.
are connected.

The slip mechanism 14 is constructed as shown in FIG.

That is, a slip gear indicated by the reference numeral 14a is fitted to a base shaft 14f fixed to the output shaft 13 via a friction flange 14b made of a material whose friction coefficient does not change easily, such as Teflon.

Another friction flange 14c made of the above-mentioned material is in contact with the other side of the slip gear 14a, and a washer 14d is in contact with the outside thereof.

Further, an adjustment ring 14g is screwed onto the tip of the base shaft 14f, and the adjustment ring 14g and the washer 14
A spring 14e is loaded between the terminal and the terminal d.

Therefore, the slip gear 14a is pressed toward the base 14f via the friction flange 14c by the elastic force of the spring 14e, and the slip gear l4. As long as the force applied to output shaft 13. Base axis 14.
Rotates with f. If such a slip mechanism is provided, the cam barrel 7 is rotated via the gear portion 7a of the cam barrel 7 which normally meshes with the slip gear 14a.

However, if the stopper 10 reaches the end of the elongated hole 11 and cannot rotate any further, the slip gear 14a
A load much larger than the elastic force of the spring 14e is applied to the slip gear 14a, and the slip gear 14a slips and does not rotate, so that no power is transmitted.

When using a drive device with such a structure, the drive motor 12 is rotated forward and backward by reversing the polarity of the child terminal 12a and one terminal 12b of the drive motor 12, which is exemplified as a DC motor, and the drive motor 12 is energized. By setting the time to the time required for the stopper 10 to come into contact with one end of the elongated hole 11 plus a predetermined margin time, the operation of the zoom lens is caused to slip at the point where the rim 10 hits one end of the elongated hole. The mechanism 14 operates and slips for the above-mentioned margin time, after which the drive motor 12 stops rotating.

Therefore, due to some trouble, the roller 5 may be removed from the groove 8.
Even if it is in position b, by rotating the drive motor 12 in a predetermined direction, the slip mechanism 14 will function and the zoom lens will always move to one of the magnification positions.

By the way, an inexpensive C motor is used as the drive source for the slip mechanism, and the distance between the lenses of the zoom lens is usually set to +0.
It is extremely difficult to position with high accuracy of 0.3 mm or less.

For example, in the case of a DC motor, the motor rotates approximately 90 degrees or more due to the inertia of the rotor within the motor after the power supply is stopped.

Therefore, it is necessary to position it mechanically, but if the slip mechanism described above is not provided, it will hit the stopper)1
When this occurs, the load applied to the motor becomes infinite, a large current flows, and the motor burns out in a few seconds.

In order to prevent such accidents, the slip mechanism described above is employed.

Even when a slip mechanism is provided, if the torque required to rotate the cam cylinder 7 is, for example, 500gΦC■, the slip mechanism needs to rotate the adjustment ring 14g to adjust the frictional force so that it slips at 800g/C11. .

When set in this manner, the DC motor rotates under a load larger than the torque required to rotate the zoom lens during the above-mentioned margin time, which is extremely inefficient in terms of power supply margin.

In an attempt to eliminate this drawback, it is possible to perform high-precision positioning by using a stepping motor or servo motor instead of a DC motor and decelerating it, but it is extremely expensive and requires a lot of effort to first determine the current position. Initialization is required.

On the other hand, when using a zoom lens that switches the magnification as described above in a facsimile machine, etc., the time for switching the magnification is limited by the communication procedure determined by the protocol, so it is necessary to perform the switching operation within that time limit. must be completed.

However, in the conventional structure, as mentioned above, it was necessary to consider the margin time, and the switching time became shorter, which meant that the power of the drive source had to be increased.

Further, the slip mechanism described above has the disadvantage that friction flanges L4b and 14c that do not cause fluctuations in the coefficient of friction must be used, and that an expensive material such as Teflon is required, resulting in high costs.

[Objective] The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide an inexpensive and highly reliable positioning device with an extremely simple configuration.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

[First Embodiment 1 FIGS. 6 to 8 illustrate a first embodiment of the present invention, and FIG. 6 shows an electric circuit.

In the following drawings, parts that are the same as or correspond to those in FIGS. 1 to 5 are given the same reference numerals.

In Fig. i6, reference numerals 21 and 22 indicate switch means, for example, microswitches are used.

Further, reference numerals 23 and 24 indicate elements that are conductive only in one direction of polarity, such as diodes.

25a and 25b are input terminals.

Figure 7 explains a specific structure using the electric circuit shown in Figure 6, and the same parts as in Figure 6 are given the same reference numerals.

In FIG. 7, the reference numeral 26 is a motor gear fixed to the output shaft of the drive motor 12, and is a gear portion 7a of the cam cylinder 7.
It meshes with.

Further, a rack gear indicated by the reference numeral 27 moves reciprocally on a guide 28 and meshes with the gear portion 7a.

On the outer surface of the rack gear 27, cam surfaces 27a, 27 are provided on the left and right sides.
A cam 27c having a shape b is provided in a protruding manner.

Moreover, what is indicated by the reference numeral 29 is a frame to which each member is attached.

Incidentally, FIG. 8 shows a schematic diagram illustrating the operation of the cam portion of the zoom lens.

In FIG. 8, for convenience of explanation 1--the centers of the cam hole 9 and the elongated hole 11 of the cam cylinder 7 are shown on the same axis 1-.

It is assumed that the roller 5 and the stopper 10 are on the same axis 1- in the -1 direction, and that when the cam cylinder 7 rotates, the roller 5 and the stopper 10 move in the direction of arrow A.

In FIG. 8, the reference numeral indicates the amount of movement of the roller 5 in the optical axis direction, that is, the amount of movement of the movable lens 2.

Further, -#1122 indicates the rotation angle of the cam cylinder 7, that is, the amount of movement of the roller 5 when the roller 5 is guided by the straight grooves 8a and 8c and the movable lens 2 is not moved.

Further, L2 indicates a rotation angle (amount of movement) during which the guide roller 5 moves in the diagonal groove 8b.

Furthermore, in -(la, -(Is), the roller 5 has a straight groove 8a.

8C indicates the rotation angle of the cam cylinder 7 from -C until the microswitch 21.22 operates, and is 15° - (l G
indicates the force 1 and rotation angle of the cylinder 7 until the collar 10 hits the end of the elongated hole 11.

Next, the operation of this embodiment configured as follows will be explained.

When the drive motor 12 rotates, the motor gear 26° causes the eleven-cylinder gear portion 7a to rotate and the rack gear 27 to move.

As the rack gear 27 moves, the cam cylinders 27a and 27b
turns on and off the left and right microswitches 21 and 22.

Here, the operating points of the microswitches 21 and 22 are shown in FIG. 8, 11:3. - (By positioning the zoom lens in the position indicated by 14, that is, the position where the lens itself does not move, the drive motor 12
At the point where the power is cut off, the motor and other interlocking drive systems operate only due to inertia, and then the stopper IO comes into contact with either end of the elongated hole, and the movement of the zoom lens is stopped. .

On the other hand, the input terminal 12a of the drive motor 12.

12b is connected to the circuit shown in FIG.
A voltage is applied to input terminals 25a and 25b of the circuit shown in the figure from a drive circuit of a device not shown.

If we assume that this voltage changes the magnification of the zoom lens between equal magnification and reduction, for example, equal magnification! , when it is desired to change the TJ, +12V is connected to the terminal 25a and the ground is connected to the terminal 25b, and vice versa when it is desired to switch to reduction.

Note that the microswitches 21 and 22 are connected in a so-called normally closed type, which is in a conductive state when the actuator is not activated.

In this state, when a positive voltage is applied to the input terminal 12a of the motor 12 and a negative voltage is applied to the input terminal 12b, the motor rotates in the direction of arrow E. When a reverse voltage is applied, the motor rotates in the direction of arrow H. The cam cylinders 7 are each indicated by an arrow F.
The rack gear 27 is rotated in the G direction and the J direction, respectively.

Therefore, when it is desired to rotate the cam cylinder 7 in the direction of arrow F, in FIG. 6, input terminal + to the input terminal 25a.

A negative voltage may be applied to 25b.

At this time, as shown in FIG. 8, the microswitch 21 is off and the microswitch 22 is on, and the current is shown in FIG.
Flows in the direction indicated by [.

Furthermore, when a reverse electric current If is applied to 1-, the cam cylinder 7 is rotated in the direction of the arrow ■, the rack gear 27 is advanced in the direction of the arrow J, the microswitch 21 is turned on, the microswitch 22 is turned off, and the current is as shown in FIG. Flows in the sign 1 direction.

By the way, when the state changes to the state shown in FIG. 7 in which the microswitch 21 is turned off, the input terminals 25a and 25b
The voltage applied to motor 1 causes the circuit to be open, and motor 1
2 input terminal 12a.

No voltage is applied to 12b, and the motor 12 is no longer excited.

However, due to the inertia of the motor rotor, etc., the drive system moves in the directions of arrows E, F, and G, and the stopper 10 hits the end of the elongated hole ti and stops in the state shown by l in FIG. The zoom lens is maintained in this state by the load it carries.

After this, when rotating the zoom lens in the opposite direction, a reverse voltage is applied to the input terminals 25a and 25b, current flows in the direction indicated by the arrows in FIG. 6, the drive system is reversed, and the arrows shown in FIG. Rotate in the H, I, and J directions. The subsequent operations are similar to those described above.

By the way, if for some reason the zoom lens remains in the intermediate position, that is, in the state shown by the symbol ■ in FIG. 8, the microswitches 21 and 22 are in the on state as shown in FIG. 12 is in a state where both forward and reverse voltages can be applied.

Therefore, in the present invention, the voltage in the direction in which the lens is desired to be rotated can be applied to the input terminals 25a and 25b without recognizing the state of the lens.
You can operate the zoom lens by applying it to .

Note that when the drive system has completely rotated in the directions of arrows E, F, and G,
When in the concave state shown in the figure, move further to arrow E.

The terminal 25a is rotated in the F and G directions.

Even if a voltage is applied to 25b, the circuit is equivalent to becoming an oven in that direction, the motor 12 does not rotate, and no unnecessary rotational force is applied to the zoom lens.

By the way, the drive system is not limited to gears, but may also use a belt, chain, etc., and the motor is not limited to a DC motor, but a pulse motor or the like may also be used.

[Second Embodiment] In the above-mentioned embodiment, the microswitch 21
．． 22 is configured to be turned on and off using a cam 27c of a rack gear, but as shown in FIG.
．． 22 may be activated.

In this case, if the rotation angle of the zoom lens exceeds 180 degrees, two cam plates may be provided corresponding to the respective microswitches 21 and 22.

Note that in addition to the microswitch, an optical sensor such as a photointerrupter may be used.

Further, the circuit shown in FIG. 6 can be applied not only to a zoom lens but also to any mechanism that performs positioning between two points.

[Third Embodiment] Fig. 1θ and Fig. 11 are for explaining a third embodiment of the present invention, in which the reference numeral 33 in the figures is a motor driver, and output terminals 33c and 33d are input terminals of the motor 12. 12
a, 12b.

Further, the reference numeral 35 indicates a CPU, which is connected to input terminals 33a and 33b of the motor driver 33.

Further, the CPU 35 is connected to the microswitches 21 and 22 via signal lines 35a and 35b.

A logic table for the motor driver 33 is shown in Table 1.

Table 1 Specific control operations are shown in FIGS. 11(A) and 11(B).

FIG. 11(A) shows the case where the motor is rotated in the direction of arrow H in FIG.
Input terminal 33a of motor driver 33 for rotation in the direction;
Apply H and L signals to 33b, respectively, and proceed to step S2.
The process is repeated until an L level signal is detected on the signal line 35b.

If an L level signal is detected on the signal line 35b, an L level signal is output to the input terminals 33a and 33b to stop the motor 12 in step S3.

Further, when it is desired to rotate the motor 12 in the direction of arrow E in FIG.
In order to rotate in the direction, an L level signal is applied to the input terminals 33a and 33b, and in step T2, an L level signal is applied to the signal line 35a.
Repeat until level signal is detected. So17, L
If a level signal is detected, a signal of L l/bell is applied to the input terminals 33a and 33b in step T3, and the motor 12 is stopped 1-.

If such a configuration is adopted, 1, micro switch 21
．． The zoom lens can be switched by detecting the on/off state of the zoom lens 22 and controlling the voltage applied to the motor 12.

[Fourth Embodiment] FIG. 12 explains the fourth embodiment of the present invention.
The signals from 5 are connected to Antogame 1 and 34 a, respectively.
34 Input b, take the AND, and select motor driver 33.
Please enter it as follows.

If such a circuit configuration is adopted, micro switch 2
The on/off state of 1.22 is controlled by a separate system from the CPU control, and the state of microswitch 21.22! The motor 12 can be controlled via the motor driver 33 by the bottom, and the zoom lens can be switched.

[Effect] Below 1. As is clear from the description, according to the present invention, there is provided a detector driving means that is coupled to a cam cylinder which rotates forward and backward by receiving a driving force, and a detector driving means that is driven by the detector driving means to control the rotation range of the cam cylinder. Since a structure including two regulating detectors is adopted, a slip mechanism unlike the conventional one is not required, the structure can be simplified, and an inexpensive and highly reliable positioning device can be obtained.

[Brief explanation of drawings]

Figures 1 to 5 explain the conventional structure, where Figure 1 is a vertical side view, Figure 2 is a perspective view, Figure 3 is a schematic exploded view of the main parts, and Figure 4 shows the drive system. FIG. 5 is a longitudinal sectional side view of the slip mechanism, FIGS. 6 to 8 illustrate the first embodiment of the present invention, and FIG. 6 is a block diagram of the control circuit. 7 is a perspective view, FIG. 8 is a developed schematic diagram of the main parts, FIG. 9 is a front view of the main parts explaining the second embodiment of the present invention, FIGS. 10 and 11 (A), (B) describes a third embodiment of the present invention, FIG. 10 is a block diagram of a control circuit, and FIG. 11 (A). (B) is a flow chart diagram, and FIG. 12 is a block diagram of a control circuit explaining a fourth embodiment of the present invention. ■... Fixed lens 2... Moving lens 3...
Movable lens barrel 4...Fixed lens barrel 5...Roller
7...Cam cylinder 8.9...Cam hole lO・
...Stopper 11...Elongated hole 12...Drive motor 13...Output shaft 21.22...Micro switch 23.24...One-way conduction elements 25a, 25b...Input terminal 26...・Motor gear 27...Rack gear 30・
...Cam plate 33...Driver circuit 34a, 3
4b...AND gate 35...CPU Figure 1 C Figure 9 Figure 10 Figure 11 (A) (B) Figure 12

Claims (1)

[Claims] a movable body movable in the axial direction; a cam cylinder rotatably fitted to the movable body, interlocking with the movable body via a cam hole and a roller, and to which rotational force from a drive source is transmitted; A positioning device comprising: a detector driving means that is linked to the rotation of the cam cylinder; and two detectors that are driven by the detector driving means and regulate a rotation range of the cam cylinder.