JP2858650B2 - Small motor device for rotary drive mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor device in a rotary drive mechanism, and more particularly, to an improvement in a small motor device applied to focusing in a lens zoom mechanism of a normal video camera or a digital video still camera. It is related to.

[0002]

2. Description of the Related Art Generally, in a video camera, a lens zoom mechanism for variably adjusting a lens magnification is driven by a small-sized motor capable of rotating forward and backward when taking an image. More specifically, the output of the rotor shaft extended through the one end flange portion after holding the small motor incorporated in the outer case against the outer surface of the one end side flange portion of the board bracket. The distal-end-side lead screw is pivotally supported on the inner surface of the other-end-side flange portion, and the rotor shaft is resiliently pressed by the elastic force of a pressing spring piece disposed on the base end side of the rotor shaft in the outer case. The actuator is pressurized in a thrust direction (axial direction), and further, for example, an operating piece that is prevented from rotating by a guide rod or the like is screwed into the lead screw, and the operating piece is connected to a lens zoom mechanism, and the compact By selectively rotating the lead screw in either the forward or reverse direction with the driving of the motor, the operation piece is advanced or retracted, and the zoom operation of the lens zoom mechanism is performed. Than is allowed.

[0003] In this type of video camera, in many cases, the peripheral audio is recorded simultaneously with the imaging of the scene while performing the zoom operation of the lens zoom mechanism by driving a small motor. Therefore, it is necessary to avoid various noises inevitably generated by driving the small motor as much as possible, and on the other hand, to further reduce the size of the entire apparatus and simplify the manufacturing process. There is also a demand for an increase in motor torque itself in accordance with the ease of assembling work.

[0004]

However, in the case of the conventional small-sized motor device having the above-mentioned structure, the rotation of the rotor with respect to the stator iron core is reduced in order to reduce the precision accompanying the miniaturization of the entire device. Is not always good, and since the bearing end plate is caulked and fixed to the open end face of the outer case incorporating the stator iron core and the rotor, the core deflection accompanying the caulking, that is, It is easy to be eccentric because the shaft support form on the shaft core collapses, and this eccentric shaft support causes a so-called wobbling phenomenon, as a result, not only generates rotational noise at the time of rotational driving, but also the motor torque is not constant, At the same time, there is an inconvenience that an unbalanced load applied to the bearing portion causes a backlash of the pivot and causes a frictional noise and a vibration noise.

[0005] Further, the mounting mode of the presser spring piece for pressing the rotor shaft of the small motor in the thrust direction (axial direction) is such that the presser spring piece is pressed into the outer case by light press-fitting into the outer case with a required fitting dimension. Due to the structure that only suppresses the floating property and backlash of the spring piece, the vibration between the outer case and the presser spring piece is caused mainly by the rotational vibration of the lead screw accompanying the driving of the small motor. Noise such as noise and fricative noise may be generated. In other words, with respect to the variation in the inner diameter of the outer case, if the size of the holding spring piece itself is about the plate thickness, the amount of the variation cannot always be effectively absorbed and noise will be generated. Since unnecessary stress is applied to the entire presser spring piece, the spring shape also changes, which may cause a change in spring pressure and, consequently, a change in motor torque.

Further, there is a disadvantage that the steps of manufacturing and assembling are complicated in response to the miniaturization of the apparatus configuration, and the work is not always easy.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem.
Incorporating resin-integral molding into the structure of the small motor itself, making the rotor pivotal support for the stator iron core accurate on a common shaft core for both, effectively eliminating the cause of noise generation, and An object of the present invention is to provide a small-sized motor device in a rotary drive mechanism which is simple in structure and is easy to manufacture and assemble so as to always obtain smooth rotation and constant output torque.

[0008]

According to a first aspect of the present invention, there is provided a small-sized motor device for a rotary drive mechanism according to the present invention, wherein a cylindrical stator iron core is inserted in an axial direction. In this state, a bobbin portion is disposed around the stator iron core with a resin material, and the non-output side end face is closed by a bearing end plate portion forming a first bearing portion on the shaft core line, and the output side is closed. A stator molded body integrally molded with resin so that the end face is opened is provided, and a stator assembly in which an exciting winding is wound on a bobbin portion, and an output side end face combined with the stator assembly is provided. Closed, and in the closed state, the first
A bearing end plate having a second bearing portion concentric with the bearing portion of the above, and a rotor having an outer diameter slightly smaller than the inner diameter of the stator core and magnetized in a required form, and A rotor assembly in which a lead screw is extended to an output side of a rotor shaft for fixing a rotor on a shaft center line, and a shaft pressing means provided with a pressing spring piece for pressing the rotor shaft to the output side, An output side is opened to form a bottomed cylindrical shape, and the shaft pressing means and the stator assembly are sequentially mounted from the opening side, and the rotor assembly is fitted inside a stator iron core. After being inserted, the output side end is closed by the bearing end plate,
An outer case for supporting a rotor shaft at both ends of the rotor on the first and second bearing portions and pressing a non-output side end portion of the rotor shaft by the pressing spring piece to house the rotor shaft; And a rotary drive mechanism for pivotally supporting the tip of the output lead screw of the rotor shaft.

According to the first aspect of the present invention, as the stator assembly, a stator end plate portion for closing the bobbin portion and the non-output side end portion is arranged and integrated with the stator iron core outsert. Since the resin is molded, the configuration of the stator assembly is simplified, and when the output side end is closed by the bearing end plate, the first and second bearings for the stator core are common. Positioned with high precision on the same axis. Further, after the shaft pressing means and the stator assembly are sequentially mounted in the outer case and the rotor assembly is inserted, the rotor shaft is first and second ends of the rotor at both ends of the rotor. The shaft support of the rotor shaft with respect to the stator core is accurately regulated, and the non-output side end of the rotor shaft is held down by the shaft pressing means. The entire device can be easily assembled by being pressed to the output side by the spring piece. In this manner, in the embodiment in which the entire apparatus is assembled, the rotor assembly can be effectively supported on the stator assembly on the same axis without causing runout, and rotated by the pressing spring piece. The child assembly can be pressed in the thrust direction with a constant elastic force. As a result, the cause of noise generation can be eliminated as expected, and smooth rotation and constant output torque can always be obtained.

According to a second aspect of the present invention, there is provided a small-sized motor device in the rotary drive mechanism according to the first aspect, wherein the shaft pressing means includes an insert base plate, and the insert base plate. A pressing spring member including a pressing spring piece cut and raised to the pressing surface side including the center portion of the pressing spring member, and the insert base plate portion is inserted into a vibration-absorbing resin body member to be integrated therewith. It is characterized by being resin molded.

According to the second aspect of the present invention, the insert base plate portion of the presser spring member is inserted into a resin body member having a vibration absorbing property and is integrally molded with the resin, and the presser spring piece is inserted from the insert base plate portion. Since the portion is protruded, the vibration applied to the pressing spring piece is effectively absorbed by the resin body member.

According to a third aspect of the present invention, there is provided a small-sized motor device in the rotary drive mechanism according to the second aspect, wherein the resin main body member of the shaft pressing means is provided on the non-pressing surface side with the outside. It is characterized in that it has a spacer portion for appropriately separating from the inner end surface of the case.

According to the third aspect of the present invention, the area of contact of the resin main body member with the inner end surface of the outer case is reduced by the spacer portion, and transmission of rotational vibration to the outer case is effectively suppressed.

According to a fourth aspect of the present invention, there is provided the small-sized motor device in the rotary drive mechanism according to the first aspect, wherein at least one of the first and second bearing portions has a bearing inner surface. And a lubricating means such as an oil groove capable of holding lubricating oil.

In the small motor device according to the fourth aspect, the rotor assembly can be smoothly rotated by lubricating means such as an oil groove provided in each of the first and second bearing portions.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a small motor device in a rotary drive mechanism according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is a longitudinal sectional view showing a schematic configuration of an entire small motor device to which an embodiment of the present invention is applied.
2 (a) and 2 (b) are a vertical sectional view and an end view showing a stator assembly of the small motor taken out. Further, FIG. 3 is a front view showing the shaft pressurizing mechanism taken out, FIG. 4 is a vertical sectional view taken along line AA of FIG. 3, and FIG.
FIG. 3 is a front view showing a pressing spring member inserted into the shaft pressing mechanism.

In the embodiment shown in each of these figures,
The small motor device has a forward / reverse rotatable small motor 10 serving as a driving source.
The stator assembly 11, the bearing end plate 21 combined with the stator assembly 11, the rotor assembly 31, and the stator assembly 11 and the bearing end are provided via a shaft pressing mechanism 40. An outer case 61 that accommodates the plate 21 and houses the rotor assembly 31. Here, the outer case 6 is separately provided.
1 is fixedly held, and a substrate bracket (corresponding to the rotation drive mechanism side) 71 that supports the rotor assembly 31 that is pressed in the thrust direction (axial direction) by the shaft pressing mechanism 40 is provided.

The stator assembly 11 is shown in FIG.
As shown in (b), two stator iron cores 12a and 12b which are cylindrically arranged in the axial direction and are arranged side by side in such a manner that the magnetic pole parts are shifted from each other are provided, and each of the stator iron cores 12a and 12b is provided. Core 12
With the a and 12b outsert, the output side end faces (corresponding to the right end side in FIG. 2A) of the stator cores 12a and 12b are kept open, and the bobbin portions 13a around the outer periphery are opened.
13b and the respective terminal extraction portions 14a and 14b on the peripheral flanges of the bobbin portions 13a and 13b, and the non-output side end faces of the stator cores 12a and 12b (corresponding to the left end side in FIG. 2A). And a bearing end plate portion 15 that forms a pivot shaft hole (corresponding to a first bearing portion) 16 on the axis of the shaft is integrally formed by resin molding. Here, for the pivot shaft hole 16, a plurality of oil grooves (not particularly shown) or the like capable of holding the lubricating oil are formed on the inner surface of the bearing in order to smoothly rotate. preferable.

A bearing end plate 21 which is combined with the stator assembly 11 and closes the output side end face includes a bearing member 22 having a pivot shaft hole (corresponding to a second bearing portion) 23 on the axis of the shaft. Holding member 2 for fitting and holding the bearing member 22
4 is substantially combined with the holding member 24.
Thereby, the output side end face of the stator assembly 11 is closed. Also in this case, for the pivot shaft hole 23, a plurality of oil grooves (not particularly shown) or the like capable of holding the lubricating oil are formed on the inner surface of the bearing in order to perform smooth rotation. preferable.

Accordingly, each stator core 12a,
Each of the bobbin portions 13a and 13b including the outer end surface 12b and the bearing end plate portion 15 for closing the non-output side end surface are integrally resin-molded to form the stator assembly 11, and the output side end portion is connected to the bearing end plate 21. Are closed by the holding members 24 of the respective pivot shaft holes 1 with respect to the stator cores 12a and 12b.
6 and 23 are accurately positioned on the same common shaft core, so that the shaft pivoting of the rotor assembly 31 described below can be satisfactorily and effectively performed, and the stator iron cores 12a, 1
The gap between the rotor 2b and the rotor of the rotor assembly 31, that is, the so-called air gap, can be assembled to a minimum, and together with the pivotal support of the lead screw in the board bracket 71 described later, the expected smoothness can be obtained. The rotation drive and the increase of the motor torque can be easily achieved.

Exciting windings 17a, 17b are wound around the bobbin portions 13a, 13b integrally formed with the stator iron cores 12a, 12b, respectively. Each terminal 18a having the winding start end and the winding end end implanted in the terminal extraction portions 14a, 14b,
18b.

The rotor assembly 31 has an outer diameter slightly smaller than the cylindrical inner diameter of each of the stator cores 12a, 12b by an amount corresponding to the air gap.
A rotor 32 composed of a magnet having an axial length within an effective range extending therebetween and magnetized in a required form;
2 is constituted by a rotor shaft 33 that penetrates and fixes the shaft 2 on a shaft core line, and a lead screw 34 that serves as an output shaft by extending the output side at the tip end of the rotor shaft 33. Spherical convex surface 3 with concentric non-output end
3a, and the tip end of the lead screw 34 is similarly formed as a concentric spherical concave surface 34a.
Then, the rotor assembly 31 is, as described above,
The rotor 32 is inserted into the stator cores 12a and 12b and assembled, and the rotor shaft 33 is connected to the rotor 32.
The main shaft of the motor is constructed by pivotally supporting the pivot shaft holes 16 and 23 at both ends thereof and pulling out the lead screw 34 to the output side.

In the case of this embodiment, the shaft pressing mechanism 40 includes an insert base plate portion 42 and a center portion of the insert base plate portion 42, as shown in FIGS. A pressing spring member 41 composed of a pressing spring piece portion 46 which is provided with a required elastic force by being cut and raised at a predetermined angle on the pressing surface side, and has a pressing spring member 41. The central portion of the presser spring piece 46 other than the cut-and-raised portion is cut into the cutout 43 over a required range, and at the right place on the plate surface, in this case, both left and right directions parallel to the presser spring piece 46. Projections 44 and holes 45 for insert connection are formed on the edge and the rear surface of the plate surface in the vertical direction, respectively. The presser spring member 41 includes an insert base plate 42 excluding the presser spring piece 46 and the hole 45.
Are inserted into a resin body member 51 having a vibration-absorbing property and molded into a resin, so that the whole of them is integrally formed. Further, the non-pressing surface side of the resin body member 51 (the cut and rise In this case, a spacer portion 52 composed of a hemispherical convex portion is protrudingly provided at an appropriate position on the surface side opposite to the side (in this case, at an equiangular interval). The spacer 52
Alternatively, for example, a ring-shaped rib portion or the like may be protruded.

The outer case 61 has a bottomed cylindrical shape with an open end on the output side, and each terminal take-out portion 14a, 14b of the stator assembly 11 is opened from the open end surface.
A notch 62 for receiving the small motor 10 is cut out to form an outer casing of the small motor 10. That is, with respect to the outer case 61, the shaft pressing mechanism 40 and the stator assembly 11 incorporating the rotor assembly 31 and pivotally supported in this order from the opening end face side toward the inside are sequentially arranged. In this state, the spherical convex surface 33a formed on the non-output side end of the rotor shaft 33 abuts against the pressing spring piece 46 of the pressing spring member 41, so that the rotor shaft 33 is axially mounted. (Thrust direction) While being pressed against the output side with a predetermined resilient force, the lead screw 34 serving as the output shaft is projected to the outside to substantially constitute the small-sized motor 10.

In this case, the substrate bracket 71 as the rotation drive mechanism side is made of a pair of flange portions 72a, 7a facing each other by using, for example, a vibration absorbing plate material such as a vibration damping plate.
2b, a center opening 73a for receiving the lead screw 34 protruding to the outside of the small motor 10 is formed concentrically with respect to the flange portion 72a on one end side, and A center opening 73b for receiving and holding a bearing member 74 with a separately provided bearing recess (corresponding to a bearing on the rotation drive mechanism) 75 is similarly formed on the flange portion 72b. Here, it is desirable that the bearing concave portion 75 retain lubricating oil on the inner surface corresponding to the bearing in order to smoothly rotate. For example, the bearing concave portion 75 is formed in a normal bearing portion form. In some cases, a plurality of oil grooves or the like may be formed on the inner surface of the bearing.

Here, in the case of this embodiment, as apparent from FIG. 1, first, as described above, the shaft pressing mechanism 40 and the stator After the assembly 11 and the assembly 11 are sequentially assembled and mounted, the rotor assembly 31 is assembled, and the opening side of the outer case 61 is closed with the bearing end plate 21. The mechanism 40 is non-movably fitted to the inner peripheral surface of the outer case 61 via a resin main body member 51 having a vibration absorbing property, and is interposed between the inner peripheral surface of the outer case 61 and the inner end surface of the outer case 61 via respective spacer portions 52. It will be indirectly contacted. In other words, by holding the contact in a smaller area, vibration transmission to the outer case 61 through the contact surface is suppressed as much as possible, and at the same time, the shaft pressing mechanism 40 is stably fixed. In the state where the rotor assembly 31 is pressed to the output side by the pressing spring piece 46 of the shaft pressing mechanism 40, the rotor assembly 31 is accurately positioned on the common shaft center line with respect to the stator assembly 11. A stable and stable motor torque is assured as well as the pressing to the output side by the presser spring piece 46 without causing rotation unevenness due to the pivotal support.

Next, with respect to the board bracket 71, the opening side closed by the bearing end plate 21 of the outer case 61 is appropriately attached and fixed to the flange part 72a at one end from the outside, and the center opening 73a is provided. The tip end of the lead screw 34 protruding inward is pivotally supported via a bearing ball 76 into a bearing recess 75 of a bearing member 74 provided on the other end side flange portion 72b, and thus the entire apparatus is assembled. Can be

That is, the small motor 10
In the state where the entire device including the stator assembly is assembled, the rotor 32 of the rotor assembly 31 extends between the respective stator cores 12a and 12b of the stator assembly 11 so that each of the pivot shaft holes on the same axis is provided. 16 and 23, and the distal ends of the lead screws 34 extended from the rotor shaft 33 are respectively supported by bearing recesses 75 via bearing balls 76 in bearing recesses 75. At the same time, the rotor shaft 33 Of the pressurizing spring member 41 provided on the shaft pressurizing mechanism 40, and the rotor assembly 31 is pressed by the elastic force applied to the pressurizing spring piece 46. In effect, the lead screw 34 can be pressed to the output side.

Therefore, according to the small motor device in the rotary drive mechanism of the present embodiment employing the above configuration, the lead screw 34 as the output shaft is selected in either the forward or reverse direction by the control drive of the small motor 10. The lead screw 34 is driven to rotate, and the screw advance / retreat operation accompanying the rotation of the lead screw 34 is taken out as a motor output. The above assembling work is not necessarily complicated, and can be easily performed in combination with the small number of parts. As a result, the cause of noise generation is effectively eliminated, and the smooth operation is always achieved. Rotation and constant output torque are obtained.

[0031]

As described above in detail with the embodiment, according to the small motor device in the rotary drive mechanism according to the first aspect of the present invention, the shaft pressing means and the stator are provided in the outer case. After the assemblies are sequentially mounted, the rotor assembly is inserted and the rotor shaft is pivotally supported on the first and second bearing portions at both ends of the rotor, and the rotor shaft is internally mounted. Since the lead screw extending from the child shaft can be pivotally supported on the rotation drive mechanism side, the shaft support of the rotor shaft with respect to the stator core is the same with the integral molding of the stator assembly. The shaft can be accurately pivoted on the shaft core, and at the same time, the rotor assembly can be pressed with a constant elastic force in the thrust direction by the pressing spring piece, and as a result, as a whole,
With a small number of parts, the entire small motor device can be assembled very easily without any skill, and the cause of noise generation is eliminated as expected, so that smooth rotation and constant output torque can always be obtained. is there.

Further, in the small-sized motor device of the rotary drive mechanism according to the second and third aspects of the present invention, as the shaft pressing means, the insert base plate portion of the pressing spring member is integrally formed in a resin main body member having a vibration absorbing property. Is formed on the non-pressing surface side of the resin main body member, and a spacer portion is formed on the non-pressing surface side of the resin body member so as to be spaced apart from the inner end surface of the outer case. Vibration can be effectively absorbed, and transmission of rotational vibration to the outer case can be suppressed well.

Furthermore, in the small-sized motor device in the rotary drive mechanism according to the present invention, lubrication of an oil groove or the like capable of retaining lubricating oil on at least one of the inner surfaces of the first and second bearing portions. The provision of the means enables smooth rotation of the rotor assembly.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of an entire small motor device to which an embodiment of the present invention is applied.

FIG. 2 is a longitudinal sectional view (FIG. 2 (a)) and an end view (FIG. 2 (b)) showing the stator assembly of the small motor taken out.

FIG. 3 is a front view showing the shaft pressurizing mechanism.

FIG. 4 is a vertical sectional view taken along the line AA of FIG. 3;

FIG. 5 is a front view showing a pressing spring member inserted into the shaft pressing mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Small motor 11 Stator assembly 12a, 12b Two-piece stator iron core 13a, 13b Bobbin part 14a, 14b Terminal extraction part 15 Bearing end plate part 16 Pivot shaft hole (first bearing part) 17a, 17b Excitation Windings 18a, 18b Terminal 21 Bearing end plate 22 Bearing member 23 Pivot shaft hole (second bearing part) 24 Holding member 31 Rotor assembly 32 Rotor 33 Rotor shaft 33a Base end side spherical shape of rotor shaft Convex surface 34 Lead screw 34a Spherical concave surface on tip end side of lead screw 40 Shaft pressing mechanism 41 Pressing spring member 42 Insert base plate portion 43 Cutout portion 44 Projecting portion 45 Hole 46 Pressing spring piece 51 Resin body member 52 Spacer 61 External Case 62 Notch 71 Board bracket (rotation drive mechanism side) 72a Flange at one end 72b Flange portion 73a one end side of the flange portion of the center opening 73b and the other end side of the flange portion of the center opening 74 bearing member 75 bearing recess 76 bearing balls

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 5/16-5/173 H02K 37/00-37/14 535 H02K 37/24 H02K 7/06

Claims (4)

(57) [Claims] In a state where a cylindrical stator core is outsert in an axial direction, a bobbin portion is disposed around the stator core with a resin material, and a non-output side end surface is aligned with the shaft core line. First
Closed by a bearing end plate part forming a bearing part of
A stator molded body integrally molded with resin so that an output side end face is opened, and a stator assembly in which an exciting winding is wound around a bobbin portion; and an output side combined with the stator assembly. A bearing end plate having an end face closed and having a second bearing part concentric with the first bearing part in the closed state; and an outer diameter slightly smaller than the inner diameter of the stator iron core. A rotor assembly having a rotor that is magnetized on the rotor, and a lead screw extending from the output side of the rotor shaft that fixes the rotor on the axis; and a presser that presses the rotor shaft to the output side. A shaft pressing means provided with a spring piece portion, an output side is opened to form a bottomed cylindrical shape, and the shaft pressing means and a stator assembly are sequentially mounted from the opening side,
And after inserting the rotor assembly inside the stator core, the output side end is closed with the bearing end plate, and the rotor shaft is fixed at both ends of the rotor at the first and second ends of the rotor. An outer case which is pivotally supported by each of the second bearing portions, and which presses the non-output side end of the rotor shaft with the presser spring piece to house the rotor case, and an output lead screw of the rotor shaft. A small motor device in a rotary drive mechanism characterized in that the distal end of the motor can be pivotally supported by the rotary drive mechanism. 2. The pressurizing spring member comprising an insert base plate portion and a presser spring piece portion cut and raised to a pressing surface side including a center portion of the insert base plate portion and projected. 2. The small motor device in a rotary drive mechanism according to claim 1, wherein the insert base plate portion is inserted into a resin body member having a vibration absorbing property and is integrally molded with resin. 3. The apparatus according to claim 2, wherein the resin body member of the shaft pressing means has a spacer portion on a non-pressing surface side for appropriately separating the inner case from the inner end surface of the outer case. Small motor device in rotary drive mechanism. 4. The rotation according to claim 1, wherein at least one of the first and second bearing portions has a lubricating means such as an oil groove capable of retaining lubricating oil on an inner surface of the bearing. Small motor device in drive mechanism.