JPH07298654A - Driver - Google Patents

Abstract

PURPOSE:To replace an electromechanical conversion element, a driving member and a slider, etc., without disassembling the entire part and moreover easily replace, clean or repair members to be driven by separately constituting members to be driven and slider and then coupling these elements at the position assuing easier removing operations. CONSTITUTION:An optical apparatus, which is used for executing various kinds of inspections while a lens is being moved, is provided with a lens unit 12 as the member to be driven at the fitting portion of a slider 4. For the fitting, a screw 13 is used and this screw 13 is threaded through a threaded hole 4c to the fitting part projected in the shape of alphabet T. Therefore, this screw can be removed from the upper direction. Accordingly, the slider 4 can be removed easily for repair, cleaning, adjustment and other purposes. In addition, a stationary member 1 forms an aperture at the heading portion of a stand 11 of the optical apparatus. Thereby, the fixing allowance 1a of the stationary member 1 can be enaged with this aperature and the set screw can be tightened or losened from the upper direction for removing the driver itself.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for driving a driven member using an electromechanical conversion element. For example, in addition to driving a lens in an optical device such as a photographing lens of a camera, a projection lens of an overhead projector, a lens of binoculars, a lens of a copying machine, a plotter or an X
The present invention relates to a drive device generally used in a device having a drive unit such as a Y drive table.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field,
There is one disclosed in Japanese Patent Laid-Open No. 4-69070. The contents will be described with reference to the schematic diagram of FIG. Figure 4 (a)
Is a lens driving device, 101 is a lens barrel that holds the lens, and 103 is a guide bar that supports the lens barrel and guides it in the optical axis direction. The guide bar 103 is the lens barrel 101.
101 formed on a support portion 101e extending from the fork 101
The lens barrel 101 is supported and guided by penetrating f.

Reference numeral 117 denotes a lens barrel supporting member and driving rod, which cooperates with the supporting portion 101e to support the lens barrel 101 and drive the lens barrel 101 in the axial direction.
The drive rod 117 has holes 113 formed in rising portions 113a and 113c provided on the drive rod support member 113.
It is inserted in b and 113d and is movable in the axial direction. The drive rod 117 has a U-shaped portion 10 extending from the lens barrel 101 in the direction opposite to the pointing portion 101e.
Holes 101 formed in both ends 101a and 101c of 1k
It penetrates b and 101d. Further, the rear end of the drive rod 117 is fixed to the front end of the piezoelectric element 112. The rear end of the piezoelectric element 112 is fixed to another rising portion 113e of the drive rod support member 113. Further, the leaf spring 114 is attached to the both ends 101a and 101c of the lens barrel 101 from the lower side in the drawing by screws 115 and 116. The leaf spring 114 is arranged to be parallel to the drive rod 117. Further, a friction portion 114c protruding upward in the drawing is formed at a substantially center of the leaf spring 114, and when the friction portion 114c contacts the driving rod 117, friction is generated between the lens barrel 101 and the driving rod 117. The lens barrel 101 can be driven. The friction is generated by the spring pressure of the leaf spring 114.

FIG. 4B shows a voltage waveform applied to the piezoelectric element 112. And FIG. 4 (b)
FIG. 1A shows a voltage waveform applied to the piezoelectric element 112 when the lens barrel 101 is moved to the right in FIG.
4B and 4B show voltage waveforms applied to the piezoelectric element 112 when the lens barrel 101 is moved leftward in FIG. 4A. When a voltage waveform as shown in FIGS. 4B and 4A is applied to the piezoelectric element 112, the piezoelectric element 112 abruptly expands at the abrupt rising portion where the voltage A changes to the voltage C. At this time, the drive rod 117 also moves to the left in FIG. 4A by the same amount as the extension amount of the piezoelectric element 112. However, in this case, the lens barrel 101 hardly moves due to inertia. Conversely, when the voltage C slowly changes to the voltage A, the piezoelectric element 112 contracts slowly, and the lens barrel 101 and the drive rod 1
The lens barrel 101 moves to the right in FIG. 4A due to the frictional force between the lens spring 17 and the frictional force between the leaf spring 114 and the drive rod 117. When the lens barrel 101 is moved leftward in FIG. 4A, a voltage as shown in FIGS. 14B and 14B is applied to the piezoelectric element 1.
12, the movement at that time is just left-right opposite to the case of driving in the right direction.

[0005]

In the conventional structure as shown in FIG. 4, since the drive rod 117 is directly fitted to the lens barrel 101, the members cannot be replaced unless the whole is disassembled. In particular, when an electromechanical conversion element such as a piezoelectric element is used for driving, it is driven by high-speed reciprocating motion, so damage to the electromechanical conversion element, driving member, slider, etc. used due to impact, adhesive fixing Failures such as peeling off of parts are large compared to other drive devices.
However, conventionally, such a case could not be easily dealt with. It is an object of the present invention to solve such problems and to obtain a configuration that allows easy replacement and repair of parts when a drive side malfunctions.

[0006] Further, when it is desired to repair or clean the members on the driven side (the lens barrel / lens in the above example), the entire assembly must be disassembled. It is an object of the present invention to solve such a problem and to obtain a configuration in which parts can be easily replaced and repaired in the event of a failure on the driven side.

Further, in the conventional structure shown in FIG. 4, the drive device itself cannot be removed without disassembling it. Therefore, it is not possible to perform an operation test on the drive unit itself, and it is necessary to take steps such as inspecting after assembling, and disassembling and adjusting again if there is a defect. Therefore, the completion of the product increases the number of steps, which in turn leads to an increase in cost. It is an object of the present invention to solve such a problem and to obtain a structure capable of performing an operation inspection without repeating assembly and disassembly.

Further, in the conventional structure as shown in FIG. 4, it is necessary to design and manufacture as a drive device dedicated to a specific device, resulting in poor mass productivity and increased cost. An object of the present invention is to solve such problems and to obtain a configuration that is highly versatile and can be used in any device.

[0009]

In order to achieve the above object, in the present invention, a stationary member and an electromechanical conversion element having one end fixed in the expansion and contraction direction to the stationary member,
A drive member coupled to the other end of the electromechanical conversion element in the expansion / contraction direction and supported so as to be movable in the expansion / contraction direction of the electromechanical conversion element, and frictionally engaged with the drive member, A slider supported so as to be movable in an expansion / contraction direction, a frictional force adding member that generates a frictional force between the driving member and the slider, and the electromechanical conversion element so that the electromechanical conversion element expands and contracts at different speeds. An electric circuit for charging / discharging an electric current, and a driving device comprising a driven member fixed to the slider, wherein the driven member and the slider are separately configured,
The feature of this is that it is connected at a position where it can be removed and operated.

[0010]

As a result, by removing the coupling between the driven member and the slider, the electromechanical conversion element, the driving member, the slider, etc. can be replaced without disassembling the whole, and the driven member can also be easily replaced or cleaned. Can be repaired. Further, the driving device can be manufactured as a single unit and incorporated into various devices to be used as the driving device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a focusing lens driving device of an assembled optical device will be described below with reference to the drawings. FIG. 1 shows a state in which a unit of a drive device adopting the present invention is disassembled (before assembly). In FIG. 1, 1 is a stationary member. The stationary member 1 is formed in a substantially columnar shape as a whole, and has a first hole 1b and a second hole 1c penetrating in the diametrical direction (vertical direction in the drawing). A bearing hole 1d is formed in the wall portion between the holes 1b and 1c. Further, a bearing hole 1e is provided coaxially with the hole 1d at the end face of the cylinder which constitutes the wall surface of the hole 1c. Further, one end of the stationary member 1 including the end face opposite to the end face functions as a fixing margin 1a for fixing the device when it is attached to a device or the like.

The piezoelectric element 2 is installed in the hole 1b.
The piezoelectric element 2 is fixed to the portion of the wall surface of the hole 1b opposite to the wall portion where the bearing hole 1d is formed, that is, the portion on the fixing margin side by adhesion. The piezoelectric element 2 expands and contracts in the longitudinal direction of the stationary member 1 when a voltage is applied via the lead wires 2a and 2b.

Reference numeral 4 denotes a slider, which is arranged in the hole 1c and is movable in the axial direction of the cylinder by using the longitudinal wall surface forming the hole 1c as a rotation stop and guide.
The slider 4 has a U-shaped portion extending upward from the main body in the figure, and a pair of through holes 4a extending in the longitudinal direction of the stationary member 1 are formed in the U-shaped portion. A groove 4b having a semicircular cross section is formed on the upper surface of the main body portion so as to connect the through holes 4a, 4a. Further, a mounting portion extends below the body portion so as to form a T shape with the body. The mounting portion is formed with a screw receiving hole 4c for connecting a driven member.

Reference numeral 3 is a drive shaft, which is provided with the bearing hole 1e from the outside.
It is inserted through the through hole 4a, the groove 4b, the through hole 4a, and the bearing hole 1d, and one end thereof is fixed to the piezoelectric element 2 by adhesion. In this state, the other end of the drive shaft is slightly projected from the bearing hole 1e. And both bearing holes 1d, 1e
The piezoelectric element 6 can move in the expansion / contraction direction while being instructed by. 7 is a leaf spring, and by a screw 9,
It is attached to the stationary member 1 so as to hold down the drive shaft 3 slightly protruding from the bearing hole 1e. As a result, the drive shaft 3 is pressed against the piezoelectric element 2 with a certain force. The pressing force can be adjusted by tightening or tightening the screw 9.

Reference numeral 5 is a friction member, and a groove 5a having a semicircular cross section is formed on the lower surface, and the drive shaft 3 is sandwiched from above toward the groove 4b. Further, a leaf spring 6 is provided above it to press the friction member 5 and the drive shaft 3 from above. The leaf spring 6 is attached to the tip of the U-shaped portion of the slider 4 with a screw 8. As a result, the drive shaft 3
A proper pressing force is generated via the friction member 5. The pressing force can be adjusted by adjusting the tightening of the screw 8. The state assembled in this way is shown in FIG. 2, and in this state it is an independent unit.

Next, FIG. 3 shows a state in which a driven member is attached to the drive unit, and the drive unit is attached to the optical device.
Will be described with reference to. This optical device is for performing various inspections and the like while moving the lens, but the details of the optical device itself are omitted and only the parts necessary for explaining the present invention are described.

In FIG. 3, a lens unit 12 is attached to the attachment portion of the slider 4 as a driven member. A screw 13 is used for mounting, and the screw 13 is screwed into a mounting portion projecting in a T shape through a screw receiving hole 4c, so that it can be removed from above. Therefore, it can be easily removed for repair, cleaning, adjustment, etc.

Further, the stationary member 1 is attached to the head of the stand 11 of the optical device. At the time of this attachment, an opening is formed in the head of the stand 11, and the stationary member 1 is formed in this opening.
The fixing allowance 1a is inserted and the set screw 10 is tightened from above. Thus, the drive device itself can be easily removed from the optical device by loosening the set screw 10, and when the piezoelectric element 2 or the slider 4 included in the drive device is damaged or peeled off and needs to be repaired, When it is necessary to inspect the drive unit alone, the drive unit can be easily removed from the optical device. Also, therefore,
Even at the time of initial assembly, the drive unit can be inspected as a single unit as shown in FIG. 2 and can be assembled after it is found to be normal. For example, when the lens unit 12 is connected only to the driving device, the driving device and the lens unit can be removed together by loosening the set screw 10, and the lens unit 12 is another member of the optical device. If it is connected to and cannot be removed, set screw 10 and screw 13
If the drive is removed, only the drive device can be removed, and the drive device can be removed as needed.

Furthermore, since this driving device is an independent unit that is not related to the structure or size of the optical device, it has a structure in which the fixing margin 1a can be fitted and fixed, and a structure that can be attached to the slider 4. It can be used in any device if Therefore, it is even possible to use the same drive device, for example, for a taking lens of a camera, binoculars, a projection lens of an overhead projector, and other optical devices. Further, the present invention is not limited to an optical device and can be used for various purposes such as an XY table, a plotter, and other various devices having a driving part, and is highly practical. In particular, since it is possible to drive straight ahead without using a motion converting device such as a gear train, it is possible to greatly simplify the configuration of the entire device by using it instead of the conventional motor.
If manufactured and sold as a single drive unit, it can be used for various purposes.

Further, when assembling the product, the electromechanical conversion element (piezoelectric element) and the driving member and the electromechanical conversion element (piezoelectric element) and the stationary member can be bonded only by the driving device alone. Curing conditions such as time curing and high temperature treatment can be used, and a device having high strength can be obtained. Further, batch processing of only the drive unit can be performed, and a large amount of bonding can be performed at one time.

Further, in the conventional device shown in FIG. 4, the portion where the piezoelectric element 112 is fixed to the drive rod supporting member 113 is cantilevered (the end of the drive rod 117 opposite to the piezoelectric element 112 is free). It is easy to vibrate because it is on the edge),
The expansion and contraction displacement of the piezoelectric element 112 could not be properly transmitted to the drive rod 117. On the other hand, in the structure of the above-described embodiment, one side of the piezoelectric element 2 is bonded to the wall portion forming the wall surface of the hole 1b, and the other side is pressed by the biasing force of the leaf spring 7 via the drive shaft 3. It is supported. By thus supporting the piezoelectric element from both sides, the portion where the piezoelectric element 2 is fixed to the stationary member 1 is less likely to vibrate, and the expansion and contraction of the piezoelectric element 2 can be properly transmitted to the drive shaft 3. Became. Moreover, since the both surfaces in the lateral direction of the stationary member 1 are supported on the surface to which the piezoelectric element 2 is adhered, vibration is further reduced and stable motion transmission is possible.

In addition, the stationary member may also play a role of protecting the piezoelectric element 2, protecting the slider, guiding the drive shaft 3, preventing rotation of the slider 4 and the lens unit 12, and fixing the drive device itself. did it. This allows
The number of parts was reduced and the device was downsized. The rotation stop between the slider 4 and the lens unit 12 can be achieved also by making the drive shaft a square shaft. Further, by applying a constant pressing force to the piezoelectric element 2 by the biasing force of the leaf spring 7, it is possible to increase the amount of expansion and contraction and the generated force of the piezoelectric element 2. In addition, the piezoelectric element 2, the stationary member 1, the piezoelectric element 2
It is possible to reduce the possibility that the adhesive bond between the drive shaft 3 and the drive shaft 3 will be peeled off, and even if the adhesive peels off, the expansion and contraction of the piezoelectric element 2 can be transmitted to the drive shaft 3 by the biasing force of the leaf spring 7. The performance of can be maintained to some extent.

If the slider 4 and the friction member 5 are magnets, the leaf spring 6 can be eliminated, and the number of parts and the size can be further reduced.

On the other hand, in the conventional device shown in FIG. 4, the contact between the drive shaft and the slider is a point contact, so that the stability and the durability of the contact portion are lacking. On the other hand, in the above-mentioned embodiment, the friction member and the slider are formed with a groove having a shape that conforms to the outer surface shape of the drive shaft, and the drive shaft 3 is sandwiched between these grooves so as to make surface contact. As a result, the stability of the frictional force and the durability of the friction surface can be increased, and the performance and reliability of the drive device can be improved. Further, the grooves may be formed in V-shape so that the drive shaft is in line contact with four lines, and the performance and reliability of the drive device can be improved much more than in the conventional case. Of course, one may be a circular groove and the other may be V-shaped.

Further, as shown in FIG. 6, the fixing margin 1a is not limited to a simple cylinder, but can be variously modified. For example, by providing a male screw or a female screw conforming to the standard at the tip of the fixing margin 1a, it becomes possible to use it in various devices and increase the mounting strength. Also, by providing a chamfer, rotation can be prevented and accurate mounting can be performed.
Further, by providing a through hole in the diameter direction and fixing with a screw or the like through the through hole, the mounting strength can be increased.

FIG. 7 is a partially modified example, and for comparison reference, the same configuration as that shown in FIGS. 1 to 3 is also shown in the upper part of the figure. In this modification, the stationary member 1
The wall surface on which the bearing hole 1e is formed is formed separately from the stationary member itself, and is fixed to the stationary member 1 with a screw. With such a configuration, only the slider 4 can be removed while the stationary member 1 is fixed, and the cost of replacing the parts of the drive device can be further reduced. Also, the degree of freedom in assembling can be further increased.

The driving device in the above embodiments is driven by the same method as the conventional one. That is, the voltage shown in FIG. 5 is applied to the piezoelectric element 12, and the voltage is gently applied to rapidly release the application, or conversely, the voltage is rapidly applied to gently release the application. Repeat the operation. As a result, the lens unit moves together with the drive shaft when the piezoelectric element expands and contracts gently, and stops when the piezoelectric element expands and contracts rapidly.

Next, an embodiment in which the present invention is applied as a driving device for a lens barrel of a camera will be described with reference to FIG. Reference numeral 26 is a piezoelectric element, and the mounting member 23
Are fixed by adhesion. The drive shaft 28 is also fixed to the end surface opposite to the end surface by adhesion. Reference numeral 24 denotes a slider, which is equivalent to that of the first embodiment (note that the slider 24 is substantially the same as the slider 24 in shape, although it is slightly different from the previous embodiment, and therefore detailed description thereof will be omitted. ). And the slider 2
The drive shaft 28 penetrates through the hole and groove formed in 4. Further, a friction member 29 having a groove is attached to the slider 24 so as to sandwich the drive shaft 28, and a leaf spring 30 is attached.
It is fixed with a screw 31 through. The leaf spring 30 has a portion protruding toward the friction member 29.
The frictional force between the friction member, the drive shaft and the slider is generated by this portion. As described above, the mounting member, the piezoelectric element, the drive shaft, the slider, the friction member, and the leaf spring are formed as an independent unit.

Reference numeral 21 denotes a fixed lens barrel, in which the lens 2
2 is installed and moves in the fixed lens barrel 21 in the optical axis direction (vertical direction in the figure). The lens 22 is attached to the slider 24 with the screw 25 as in the first embodiment. On the other hand, the piezoelectric element 26 is attached inside the fixed barrel 21 via the attachment member 23. The attachment member 23 is attached to the fixed barrel 21 with a screw 27.

In this state, by applying a voltage as shown in FIG. 5 to the piezoelectric element 26, the lens 22 can be operated in the optical axis direction. Therefore, it is possible to directly move the focusing lens, the zoom lens, and the like in a straight line.

The same effects as those of the first embodiment can be obtained by inspecting only the drive unit alone before assembling, or removing the drive unit only when repairing a failure. It will be complicated and will not be repeated.

[0032]

As described above, since the driving device of the present invention is unitized and the driven member is detachable, it has high versatility and can be applied to any driving device. can do. Further, since it is unitized, it can be detached independently in the event of a failure, etc., and repair / replacement is easily possible.

[Brief description of drawings]

FIG. 1 is an assembly explanatory diagram of a first embodiment of the present invention.

FIG. 2 is a perspective view of the first embodiment.

FIG. 3 is a perspective view of an optical device that employs the first embodiment.

FIG. 4 is a perspective view of a conventional drive device.

FIG. 5 is an explanatory diagram showing a voltage applied to the electromechanical conversion element in the first embodiment.

FIG. 6 is a perspective view showing a modified example of the first embodiment.

FIG. 7 is a perspective view showing another modification of the first embodiment.

FIG. 8 is an assembly explanatory diagram of a second embodiment of the present invention.

[Explanation of symbols]

 1, 21 Static member 2, 26 Electromechanical conversion element 3, 28 Driving member 4, 24 Slider 5, 6, 29, 30 Friction force applying member 4c, 13 Mounting structure 1a Mounting portion

Claims (10)

[Claims] 1. A stationary member, an electromechanical conversion element having one end fixed in the direction of expansion and contraction to the stationary member, and receiving a voltage applied thereto so as to expand and contract at different speeds during expansion and contraction, A driving member coupled to the other end of the electromechanical conversion element in the expansion / contraction direction and supported so as to be movable in the expansion / contraction direction of the electromechanical conversion element, and frictionally engaged with the drive member, and the expansion / contraction direction of the electromechanical conversion element. A slider that is movably supported and that can be mounted with a driven member; and a frictional force adding member that generates a frictional force between the driving member and the slider, wherein: A drive device having a mounting structure for detachably mounting a driven member, wherein each of the above members is unitized. 2. The drive device according to claim 1, wherein the stationary member has a mounting portion that can be attached to and detached from another device. 3. The drive device according to claim 2, wherein the mounting portion is a screw. 4. The drive device according to claim 2, wherein the mounting portion is a through hole. 5. The drive device according to claim 2, wherein the mounting portion is a mounting margin protruding so as to be inserted into an opening formed in the other device. 6. The drive device according to claim 5, wherein the mounting margin has a detent structure for preventing rotation. 7. The electromechanical conversion element according to claim 1, wherein the other end is pressed and supported toward the one end by being connected to the stationary member via the driving member. Drive. 8. The drive device according to claim 1, wherein a moving guide of the slider is integrally provided on a stationary member. 9. The drive device according to claim 1, wherein a magnet is used as the frictional force applying member. 10. The drive device according to claim 1, wherein a portion of the stationary member that supports one end of the electromechanical conversion element is supported on both sides thereof.