JPH08184742A - Feed screw mechanism - Google Patents

Abstract

PURPOSE: To reduce time number of parts by guiding a part to be guided which is provided in a nut part by means of a guide shaft by which a moving member is guided. CONSTITUTION: By slidably inserting the guide shaft 23 through a guide hole 19a formed on the moving member 16 and a guide hole 28a formed in the nut part 25, the moving member 16 and the nut part 25 are slidably supported on the guide shaft 23. When a driving motor is driven, a feed screw 26 is rotated and the nut part 25 where the tooth of a tooth part 32 is engaged in the guide hole 28a is guided and moved by means of the guide shaft 23. Furthermore, the contact surface 22 of an engaging hole 21 formed on the moving member 16 is pressed by the contact part 36 of an engaging projection 35 protrusively provided at the upper edge of the nut part 25 with the movement of the nut part 25, the guide hole 19a of the moving member 16 is guided by the guide shaft 23, and the guide groove of a guide arm is guided by the guide shaft, so that a movable lens holder is moved in an optical axis direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel feed screw mechanism. Specifically, a new feed screw mechanism that prevents the vibration of the feed screw and the vibration of the nut portion due to the misalignment between the feed screw and the nut portion from being transmitted to the moving member without increasing the number of parts or complicating the mechanism. Is to provide.

[0002]

2. Description of the Related Art Below, different conventional feed screw mechanisms are shown in FIGS.

FIG. 8 shows a conventional feed screw mechanism a having a nut portion b and a feed screw c.

The main portion d of the nut portion b has a plate-like shape, and a retaining claw e is vertically provided on the main portion d, and an engaging projection f is provided so as to project upward. Is provided with a guide hole g,
Teeth h, h, ... Are protrudingly provided on the surface of the main portion d facing the holding claw e side.

Reference numeral i denotes a frame formed by bending a plate-like member into a U-shape, which is fixed to a camera lens barrel (not shown), a motor j is supported by the frame i, and a feed screw c is interposed through a bearing. Supported by a motor j
Is connected to the rotating shaft of.

A guide shaft k for guiding the nut portion b is fixed in parallel to the feed screw c at the upper corner of the frame i, and the guide shaft k slides in a guide hole g of the nut portion b. It is freely inserted.

Reference numeral 1 denotes a moving member formed in a cylindrical shape,
A guide hole m is provided so as to extend in the axial direction, and a guide shaft n fixed to a camera lens barrel (not shown) is provided in the guide hole m.
Is slidably inserted.

An engaging hole o opened on the lower surface of the moving member l is formed, and an engaging projection f projecting from the main portion d of the nut portion b is engaged with the engaging hole o. By
The nut part b and the moving member 1 are connected.

Reference numeral p is a movable lens holder, and q is a guide arm projecting above the movable lens holder p.

A guide groove r is formed at the tip of the guide arm q, and is slidably engaged with a guide shaft s fixed to a camera lens barrel (not shown).

Reference numeral t denotes a holding arm projecting from below the movable lens holder p, and the moving member 1 is connected to the tip of the holding arm.

Xx is the optical axis of the lens u held by the movable lens holder p.

The holding claw e of the nut portion b and the main portion d are positioned so as to sandwich the feed screw c, so that the teeth h of the main portion d are engaged with the feed screw c. Then, by rotating the feed screw c, the guide hole g of the nut portion b
Is guided by the guide shaft k, the nut portion b is moved in the axial direction of the feed screw c, and the engagement protrusion f of the nut portion b is moved.
When the movable member 1 is pressed through the guide hole m, the guide hole m is guided by the guide shaft n and moved.

Then, the movable lens holder p fixed to the moving member 1 via the holding arm t is moved with the guide groove r of the guide arm q guided by the guide shaft s.

FIG. 9 shows another example a2 of the conventional feed screw mechanism. It should be noted that the feed screw mechanism a2 of FIG. 9 is different from the feed screw mechanism a of FIG. 8 only in the shapes of the feed screw mechanism and the moving member.
Since it is the same as that of the feed screw mechanism a, the same parts as those of the feed screw mechanism a of FIG. To do. The method of attaching such reference numerals is the same for the feed screw mechanism a3 shown in FIG.

The feed screw mechanism a2 has a nut portion b2 and a feed screw c2.

The main portion d2 of the nut portion b2 has a rectangular plate shape, and a screw hole e2 into which a feed screw c2 is screwed is formed in the center, and engaging protrusions f2, f2, ... Is projected.

Reference numeral g2 is a moving member formed in a cylindrical shape, and a guide hole h2 is axially provided therethrough, and a guide shaft n fixed to a camera lens barrel (not shown) slides in the guide hole h2. It is inserted freely.

An elliptic connecting portion i2 is vertically provided at the lower end of the moving member g2, and extends 2 to the side of the connecting portion i2.
Engaging protrusions j2, j2, ...
・ ・ Is projected.

K2, k2 are connecting members made of an elastic material such as rubber, and have engagement holes 12, 12, ...

.. and the movable member g2 are connected to the connecting portion i2 of the nut b2.
, Are engaged with the engaging protrusions j2, j2, ..., Which protrude upward and downward, so that the nut portion b2 causes the connecting member k2 ,. It is connected to the connecting portion i2 via k2.

When the motor (not shown) is rotated, the feed screw c2 connected to the rotary shaft of the motor is rotated, and the nut portion b2 screwed to the feed screw c2 is connected to the feed screw c2. When the moving member g2 is moved in the axial direction and pressed by the connecting members k2, k2, the moving member g2 is moved with its guide hole h2 being guided by the guide shaft n.

The vibration generated by the shaft deviation of the feed screw c2 is prevented from being transmitted to the moving member g2 by being absorbed by the connecting members k2 and k2, so that the movable lens holder p is moved to the nut member b2. And is not affected by the vibration of the feed screw c2.

FIG. 10 shows another example a3 of the conventional feed screw mechanism.
And has a nut portion b3 and a feed screw c3.

The main portion d3 of the nut portion b3 has a cylindrical shape, and a restraining plate e3 and an engaging plate f3 are vertically extended from the main portion d3 in a figure eight shape, and face the restraining plate e3 side of the engaging plate f3. Teeth g3, g3, ... Are projected on the surface.

The feed screw c3 is rotated by being connected to a rotary shaft of a motor (not shown).

Reference numeral h3 is a moving member formed in a cylindrical shape, and a guide hole i3 is axially provided therethrough, and a guide shaft n fixed to a camera lens barrel (not shown) slides in the guide hole i3. It is inserted freely.

On the outer peripheral surface of the moving member h3, nut supporting parts j3, j3 are formed which are provided at appropriate intervals in the axial direction and project in a direction orthogonal to the axial direction. The nut supporting parts j3, j3 are formed. By supporting both ends of the rotating shaft k3 inserted into the main part d3 of the nut part b3, the nut part b3
Is rotatably supported by the moving member h3.

The holding plate e3 of the nut portion b3 and the engaging plate f3 are positioned so as to sandwich the feed screw c3, so that the teeth g3, g3, ... Of the engaging plate f3 are engaged with the feed screw c3. When the feed screw c3 is rotated, the nut portion b3 is moved in the direction indicated by the arrow, so that the moving member h3 is guided and moved by the guide shaft n.

[0030]

However, in the above-mentioned conventional feed screw mechanism a, the nut portion b moves in the axial direction due to the displacement of the feed screw c or the meshing of the feed screw c and the nut portion b. There is a problem that the guide shaft k and the frame i are required in order to prevent blurring when performing, and the number of parts increases.

Further, in another example a2 of the conventional feed screw mechanism, the connecting members k2, k2 made of elastic members are bridged between the nut part b2 and the connecting part i2 of the moving member g2. It is possible to prevent the shake of the nut portion b2 from being transmitted to the moving member g2, but there is a problem that the structure becomes complicated.

Further, in another example a3 of the conventional feed screw mechanism, the movement of the nut portion b3 is indirectly guided by the guide shaft n through the rotation shaft k3, the nut support portion j3 and the like. There is.

Therefore, the nut portion b3 due to the runout of the feed screw c3 or the engagement of the feed screw c3 and the nut portion b3.
Vibration in a direction perpendicular to the axial direction of is easily transmitted to the moving member h3.

When the feed screw mechanism a3 used for moving the optical system, such as the movable lens holder p, vibrates, the center of the movable lens holder p shifts with respect to the optical axis xx. There is a problem that the image shake is caused by tilting.

[0035]

The lead screw mechanism of the present invention comprises:
In order to solve the above-mentioned problems, the guided portion provided on the nut portion is guided by the guide shaft on which the moving member is guided, and the nut portion and the moving member are moved in a direction orthogonal to the axial direction of the guide shaft. It is connected as much as possible.

[0036]

Therefore, according to the feed screw mechanism of the present invention, it is not necessary to newly provide a guide shaft for guiding the nut portion, so that the number of parts can be reduced and the nut portion moves along the guide shaft. By making it difficult for a force other than the applied force to be transmitted to the moving member, it is possible to make it difficult for the moving member to be affected by deflection of the feed screw, engagement of the feed screw, and the like.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the feed screw mechanism of the present invention will be described below with reference to the illustrated embodiments.

1 to 7 show an embodiment of the feed screw mechanism of the present invention. In this embodiment, the feed screw mechanism of the present invention is applied to the feed screw mechanism in the camera lens barrel 1.

Reference numeral 2 is an outer casing of the camera lens barrel 1.
It is formed by connecting the front half 3 and the rear half 4 in the front-rear direction (the left side in FIG. 1 is the front and the right side is the rear).

5 is the first lens group, 6 is the second lens group, and 7 is
Is a third lens group, and 8 is a fourth lens group.

The four lens groups 5, 6, 7 and 8 are
The optical axes X-X extending in the front-rear direction through the center of the outer casing 2 when viewed from the front-rear direction are arranged in common in the above-described order from the front side.

The first lens group 5 is attached to a mounting hole 9a formed in the front plate 9 of the front half 3 of the outer casing 2, and the third lens group 7 is attached to the front plate 10 of the rear half 4 of the outer casing 2. The first lens group 5 and the third lens group 7 are fixed to the front and substantially the center of the outer casing 2 by being attached to the formed mounting hole 10a.

Reference numeral 11 denotes a movable lens holder for the second lens group 6, which has a cylindrical main portion 12, a plate-like guide arm 13 projecting above the main portion 12, and a downward projecting arm 13. The holding arm 14 is integrally formed, and the second lens group 6 is attached to the mounting hole 12a of the main portion 12.

A guide groove 13a is formed at the tip of a guide arm 13 projecting above the movable lens holder 11, and is moved upward between the front plate 9 of the front half 3 and the front plate 10 of the rear half 4. The guide groove 13a of the guide arm 13 is slidably engaged with the guide shaft 15 spanning the open position.

A cylindrical moving member 16 is integrally formed at the lower end of the holding arm 14 projecting below the movable lens holder 11, and a part of the lower end of the peripheral wall portion 17 of the moving member 16 is formed. By cutting off, the housing opening 18 for housing the nut member described later is opened downward.

The front plate 19 and the rear plate 20 of the moving member 16 have substantially the same shape.
Guide holes 19a and 20a are formed at the center of the engaging member 2 and the engaging hole 2 that is long in the circumferential direction is formed at the upper end of the peripheral wall portion 17 of the moving member 16.
1 is formed, and front and rear surfaces of the inner surface of the engagement hole 21 are contact surfaces 22, 22.

Then, the guide hole 19 of the moving member 16 is provided.
A guide shaft 23 is slidably inserted between a and 20a at a position closer to the lower side between the front plate 9 of the front half 3 and the front plate 10 of the rear half 4.

A feed screw mechanism 24 has a nut portion 25 and a feed screw 26 formed of synthetic resin.

The main portion 27 of the nut portion 25 has a cylindrical shape, and the front plate 28 and the rear face plate 29 of the main portion 27 have substantially the same shape. Guide holes 28a and 29a are formed at the centers of the front and rear double-sided plates 28 and 29.

A part of the lower end of the peripheral wall portion 30 of the main portion 27 of the nut portion 25 is cut off, and a plate-like restraining piece 31 and a tooth portion 32 are vertically provided from the substantially center of the side surface of the peripheral wall portion 30. There is.

A stopper 33 is formed by driving the substantially central portion of the pressing piece 31 in the vertical direction toward the tooth portion 32 side in a V shape when viewed from the front-back direction.

The entire tooth portion 32 is bent in a V shape when viewed from the front-rear direction, so that the distance between the tooth portion 32 and the restraining piece 31 is substantially the same as the diameter of the feed screw 26 or a narrow distance.
Teeth 34 are provided on the inner surface, that is, on the lower side from the center of the surface facing the restraining piece 31.

An engaging projection 35 is provided at a position near the rear end of the upper end of the peripheral wall portion 30 of the main portion 27 of the nut portion 25.
The portion of the engaging projection 35 excluding the base end portion is a contact portion 36 in which the upper end and the left and right side portions of the sphere are removed.

Reference numeral 37 denotes a drive motor, which is fixed to a mounting piece 10b integrally provided on the lower surface of the front portion of the rear half 4 and the feed screw 26 connected to the rotating shaft thereof is connected to the front plate 9 of the front half 3. Mounting piece 1 for the rear half 4 and the bearing 38 fixed to the
It is positioned directly below the guide shaft 23 by being rotatably supported by the bearing 39 fixed to the guide shaft 23.
It is arranged so as to extend in parallel with.

Then, the feed screw 26 is sandwiched between the pressing piece 31 of the nut portion 25 and the tooth portion 32, and the force of holding the feed screw 26 by the holding piece 31 is utilized.
The teeth 34 of the teeth 32 are engaged with the lead screw 26.

Then, the main portion 27 of the nut portion 25 is accommodated in the accommodation opening 18 of the moving member 16, and the nut portion 2
The engaging projection 35 projecting from the upper end of 5 is fitted into the engaging hole 21 formed in the upper end of the moving member 16, and the contact portion 36 of the engaging projection 35 and the contact surfaces 22 and 22 of the engaging hole 21 are fitted. Make point contact.

Then, the guide holes 19a and 20a formed in the moving member 16 and the guide hole 2 formed in the nut portion 25 are formed.
The moving member 16 and the nut portion 25 are attached to the guide shaft 23 by slidably inserting the guide shaft 23 into 8a and 29a.
Supported slidably on.

When the drive motor 37 is driven, the feed screw 26 is rotated, and the nut portion 25 in which the tooth 34 of the tooth portion 32 is engaged with the feed screw 26 has the guide hole 28.
a and 29a are guided and moved by the guide shaft 23.

With the movement of the nut portion 25, the contact portions 36 of the engaging projection 35 provided on the upper end of the nut portion 25 push the contact surfaces 22, 22 of the engaging hole 21 formed in the moving member 16 to move the nut portion 25. The mold lens holder 11 is moved in the optical axis XX direction by guiding the guide holes 19a and 20a of the moving member 16 by the guide shaft 23 and the guide groove 13a of the guide arm 13 by the guide shaft 15. .

When the movable lens holder 11 is moved, the rotation of the feed screw 26 causes a deflection of the rotating shaft and the nut portion 25 and the feed screw 26 are meshed with each other. A slight vibration in the Y direction may occur.

However, the connection between the nut portion 25 and the moving member 16 is due to the contact portion 36 of the engaging projection 35 and the contact surfaces 22, 22 of the engaging hole 21, and the contact portion 36 of the engaging projection 35 is engaged. Since it is supported so as to be movable in the Y direction in the fitting hole 21, the minute vibration generated in the nut portion 25 is not transmitted to the moving member 16.

Therefore, the movable lens holder 11 can transmit only the force of the feed screw 26 in the axial direction without vibrating slightly, so that the second lens group 6 held by the lens holder 11 can be imaged. It can be moved without shaking.

Further, the force in the arrow Z direction shown in FIG. 2 applied to the nut portion 25 by the forward and reverse rotation of the feed screw 26 is that the contact portion 36 of the engaging projection 35 moves in the engaging hole 21 in the circumferential direction. Since the nut portion 25 swings and absorbs the neck, the second lens group 6 held by the lens holder 11 is not affected by the forward and reverse rotations of the feed screw 26.

The stopper 33 of the restraining piece 31 has the nut portion 25.
When the person shakes his / her head, the feed screw 26 moves upward to move the teeth 3
The movement is regulated by abutting on the feed screw 26 so as not to come off from the second tooth 34.

Reference numeral 40 denotes a lens holder of the fourth lens group 8, which comprises a main portion 41 having a cylindrical shape, a holding arm 42 protruding above the main portion 41, and a guide arm 43 protruding downward. The fourth lens group 8 is integrally formed and is attached to the mounting hole 41a of the main portion 41.

A guide groove 43a is formed at the tip of a guide arm 43 projecting downward from the lens holder 40, and is moved downward between the front plate 10 of the rear half 4 and the rear face plate 44 of the rear half 4. The guide shaft 45 spanning the position is slidably engaged with the guide groove 43a of the guide arm 43.

The moving means for moving the movable lens holder 40 of the fourth lens group 8 is the moving means for moving the movable lens holder 11 of the second lens group 16 and the feed screw mechanism 2.
Since it is the same as 4, the lens holder 1 of the second lens group 6
The description will be omitted by giving the same reference numerals to the feed screw mechanism 24 that is the first movable means.

[0068]

As is apparent from the above description, in the feed screw mechanism of the present invention, the moving member is provided with the nut portion moved by the rotation of the feed screw and the guided portion guided by the guide shaft. A guide screw mechanism in which a nut portion is formed separately from a moving member to connect the nut portion and the moving member, and a guided portion provided in the nut portion guides the moving member. And the nut member and the moving member are connected so as to be movable in a direction orthogonal to the axial direction of the guide shaft.

Therefore, according to the feed screw mechanism of the present invention, since it is not necessary to newly provide a guide shaft for guiding the nut portion, the number of parts can be reduced and the nut portion can move along the guide shaft. By making it difficult for a force other than the applied force to be transmitted to the moving member, it is possible to make it difficult for the moving member to be affected by deflection of the feed screw, engagement of the feed screw, and the like.

The specific shapes and structures shown in the above embodiments are merely examples of the implementation of the feed screw mechanism according to the present invention, and the technical scope of the present invention can be achieved by these. Should not be construed as limiting.

[Brief description of drawings]

1 shows an embodiment of the feed screw mechanism of the present invention together with FIGS. 2 to 7, which is a vertical cross-sectional view of the whole.

FIG. 2 is an enlarged front view of a main part.

FIG. 3 is an enlarged exploded perspective view of a main part.

FIG. 4 is an enlarged plan view showing a part of a main part cut away.

FIG. 5 is an enlarged bottom view of the main part.

FIG. 6 is an enlarged side view showing a notched part of a main part.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 shows an example of a conventional feed screw mechanism together with FIGS. 9 and 10, and this figure is a perspective view of a main part.

FIG. 9 is a perspective view of a main part showing another example of a conventional feed screw mechanism.

FIG. 10 is a perspective view of a main part showing still another example of a conventional feed screw mechanism.

[Explanation of symbols]

 1 Lens barrel for camera 11 Movable lens holder 16 Moving member 19a Guide hole (guided part) 20a Guide hole (guided part) 21 Engagement hole 22 Contact surface 23 Guide shaft 24 Feed screw mechanism 25 Nut part 26 Feed screw 28a Guide hole (guided part) 29a Guide hole (guided part) 35 Engagement protrusion 36 Contact part

Claims (6)

[Claims] 1. A nut part and a moving member, wherein a nut part moved by rotation of a feed screw and a guided part guided by a guide shaft are provided in a moving member, and the nut part is formed separately from the moving member. A feed screw mechanism configured to connect with a guide shaft provided on the nut portion and guided by a guide shaft on which the moving member is guided. 2. The feed screw mechanism according to claim 1, wherein the nut portion and the moving member are connected so as to be movable in a direction orthogonal to the axial direction of the guide shaft. 3. A nut and a moving member, one of which is formed with an engaging projection that is projected in a direction orthogonal to the axial direction of the guide shaft, and is inserted into an engaging hole formed in the other. 3. The feed screw mechanism according to claim 2, wherein the feed screw mechanism is connected by. 4. The feed screw mechanism according to claim 3, wherein the contact surface of the engagement hole and the contact portion of the engagement protrusion are in substantially point contact. 5. The feed screw mechanism according to claim 4, wherein the contact surface of the engagement hole is a surface orthogonal to the axial direction of the guide shaft. 6. The claim 1, claim 2, claim 3, claim 4 or claim 5, wherein the feed screw mechanism is a driving means of a movable lens holder of a lens barrel for a camera. The described feed screw mechanism.