JP2007014065A - Bearing oil scattering preventive structure and vibrating motor equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep bearing oil in a bearing sliding part always stably by damming the movement of the bearing oil of a bearing sliding part even if a vibrating motor rotates thereby preventing the bearing oil from scattering to its outside. <P>SOLUTION: In the thrust sliding part of a vibrator which includes a bearing part that is positioned at one end on the output shaft side of the housing case body of the vibrating motor where an eccentric weight is attached to its rotating shaft and a thrust washer that is arranged, being passed onto the rotating shaft between the above bearing part and the above eccentric weight, a spacer cap roughly pan-shaped in cross section is interposed separately on the rotating shaft between the above eccentric weight and the above thrust washer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cylindrical vibration motor in which an eccentric weight is attached to a rotating shaft, and more particularly to a bearing oil splash prevention structure for a bearing sliding portion that supports the rotating shaft.

  2. Description of the Related Art Conventionally, a vibration generator as a silent call function mounted on a mobile phone or the like has mainly employed a small vibration motor in which an eccentric weight is attached to a rotation shaft of an output shaft. Due to its special usage, such a small vibration motor has an electrical effect on the rectifying mechanism due to the sliding and lubrication of the bearing that supports and supports the eccentric weight that swings around at the position of eccentric gravity. This is one of the major factors that determine the life of the drive motor body.

  In particular, the coreless motor with an internal structure that combines a resin-integrated bearing with the motor housing case is compared with a bearing structure that uses a general oil-impregnated metal sintered bearing (hereinafter referred to as an oil-impregnated bearing). And the drop in durability is remarkable. Normally, bearings are individually provided at both end portions of a cylindrical motor housing, and a rotary shaft with an eccentric weight is supported by two bearing portions, and the sliding friction with the rotary shaft on the sliding surface is supported. Reduced.

At the same time, the oil in the oil-impregnated bearing is held by arranging a slip buffer member called a thrust washer between the motor housing case and the eccentric weight against the force acting in the thrust direction of the rotating shaft during the rotating operation. A structure has already been proposed. (For example, Patent Document 1 and Patent Document 2)
JP 2001-314059 A JP 2005-20959 A

  However, in the contents described in the above-mentioned patent document, it is difficult and sufficient to prevent the bearing oil from scattering even if a thrust washer is actually arranged and the thrust washer is restricted from rotating. The problem was not solved.

  An example of a structure using only a conventional thrust washer is shown in FIGS. Each symbol in the figure indicates an eccentric weight 3, a thrust washer 4e, a rotating shaft 6 and a bearing 7. FIGS. 9 (a) and 10 (c) show the flow of bearing oil after the motor rotation is stopped. b) and FIG. 10 (d) are enlarged reference views of the thrust sliding portion in the vicinity of the bearing 7 schematically illustrating the flow of the bearing oil during the motor rotating operation.

  In the vibration motor shown in FIGS. 9 and 10, the mounting position of the eccentric weight 3 is close to the bearing 7 and the thrust washer 4e itself is attached to both the side surface of the eccentric weight 3 and the bearing 7 as compared with the patent document. Since it is almost in contact, there is no distance from the eccentric weight 3, and as a result, it is not a measure for preventing scattering, and a gap effective for preventing rotation cannot be obtained.

  As shown in FIG. 11, in the case of the vibration motor 1 with the eccentric weight 3 attached to the tip of the rotating shaft, when the eccentric weight 3 having a high specific gravity is rotated and vibrated, the vibration motor 1 as a whole is caused by the centrifugal force having the eccentric gravity center. Generates a swinging force around the center of gravity G. Along with this, centrifugal force and thrust force (arrow V) are applied, and as shown in FIG. 10 (d), the bearing oil (F1) held in the sliding portion of the bearing 7 is changed to the bold arrow shown in the figure. As shown in the flow, the phenomenon is that the thrust washer 4e side surface (F2) outer periphery (F3) is transmitted to the eccentric weight 3 side end surface (F4) and scattered to the outer circumferential direction (F5) of the eccentric weight 3. As a result, there has been a problem of a reduction in motor life due to the bearing 7 running out of bearing oil.

  As a measure for preventing the bearing oil scattering, for example, the thrust washer material is changed to a porous resin material impregnated with the bearing oil to improve the oil retention of the bearing oil, or to change the viscosity of the bearing oil. It is conceivable to prevent scattering. However, if a special resin material is used, the material cost is high, and even if the viscosity of the bearing oil is adjusted, it may be difficult to prevent the scattering depending on the use conditions and temperature.

  In other words, with just a flat thrust washer 4e, the bearing oil leaking from the sliding portion of the bearing 7 is transmitted along the surface of the thrust washer 4e itself, and from the side end face of the eccentric weight 3 due to vibration and the centrifugal force of the swing. It will flow out. As a result, apart from the bearing oil (F6, F7) that returns to the sliding portion of the original bearing 7 even if rotation stops, the bearing oil is not limited to bearing oil (for example, F4, as shown in FIG. 10 (c)). , F5) is a problem of improvement item.

  In order to solve the above-mentioned problems, the present invention prevents the movement of the bearing oil in the bearing sliding portion up to the thrust washer even if the vibration motor is rotated, and the bearing oil is further scattered outside. An object of the present invention is to provide a structure for preventing and always stably retaining bearing oil in a bearing sliding portion. It is another object of the present invention to provide a simple structure of a thrust sliding portion that does not cost much without making a major design change on the motor body side.

In order to solve the above-mentioned problem, in the invention according to claim 1,
A bearing portion located at one end of the output shaft side of the housing case body of the vibration motor having an eccentric weight attached to the rotation shaft;
A thrust washer that is inserted through a rotating shaft between the bearing portion and the eccentric weight;
In the thrust sliding part of the vibration generator comprising:
On the rotating shaft between the eccentric weight and the thrust washer, a dish-shaped spacer cap having a substantially concave cross section is separately inserted and arranged.

In the invention according to claim 2, in the vibration motor according to claim 1,
The spacer cap has a substantially concave dish shape with an eccentric weight side serving as a bottom,
The dish-shaped receiving surface side has a circular depression containing a thrust washer in the thickness direction,
And a circle-shaped deep groove portion is formed on the bottom side in the outer peripheral direction of the dish-shaped receiving surface,
Furthermore, between the circumferential portion of the thrust washer and the inner circumferential surface of the spacer cap,
An annular void region following the deep groove portion has an internal shape provided on the entire circumference.

In the invention according to claim 3, in the vibration motor according to claim 2,
The spacer cap is formed by resin molding.

According to a fourth aspect of the present invention, in the vibration motor according to the third aspect, the spacer cap is formed of a resin molding material having low wettability with the bearing oil as compared with the thrust washer.

According to invention of Claim 1 or Claim 2,
It is possible to reliably prevent the bearing oil from flowing out and splashing from the bearing sliding portion that occurs during the rotation operation of the vibration motor, and to stably hold the bearing oil on the bearing sliding portion at all times. Stabilization of rotation and longer life are possible.

  In other words, with only a flat thrust washer, the bearing oil leaking from the bearing sliding part is transmitted through the surface of the thrust washer itself by surface tension, and then flows out in contact with the side end face of the eccentric weight that abuts. However, by disposing the spacer cap of the shape and material, bearing oil accumulates in the gap provided between the thrust washer and the spacer cap and is dammed up. Also, when the accumulated bearing oil stops rotating, it returns to the bearing sliding portion, and the smooth circulation and fluid volume of the bearing oil can always be kept almost constant, which can solve the problem of bearing oil shortage due to scattering. .

  In addition, it is possible to provide a simple anti-scattering structure that does not require manufacturing costs by combining with the current components without making a major design change of the vibration motor itself.

  Similarly, according to the invention described in claim 3 or claim 4, by forming the spacer cap by resin molding, it is possible to easily form a small component of a material that is inexpensive and excellent in wear resistance, like the thrust washer. The scattering prevention structure which can be manufactured and does not require manufacturing cost can be provided. Furthermore, using the difference in material wettability between the spacer cap and the thrust washer, the bearing oil is retained on the surface of the thrust washer, and the spacer cap prevents splashing. It becomes possible to make it easy to return to the part side.

  The best mode of the vibration motor of the present invention will be described below with reference to the drawings.

<Embodiment 1>
FIG. 1 shows a structural example of a vibration motor according to an embodiment of the present invention. The vibration motor 1 in FIG. 1 has a cylindrical coreless motor structure in which an eccentric weight 3 is attached to the output shaft side of the rotary shaft 6, and as shown in FIG. 12, the outer periphery of the housing case 10 of the motor body. Vibration generation of the type in which the power supply terminal 5 of the terminal block 12 is electrically pressed and joined to the circuit board by the elastic body holder 100 having a substantially square shape attached to the part and fitted into the housing side holding frame of the portable device. Device.

  The vibration motor 1 in FIG. 1 has a resin-integrated bearing 7 that penetrates the inside and outside of the fitting port of the housing case 10, unlike a structure in which a plurality of general sintered metal oil-impregnated bearings are provided at both ends of the motor body case. Yes. The bearing 7 supports the cylindrical magnet 8 on the outer periphery of the integrally formed cylinder on the inner side of the housing case 10, and also supports the rotating shaft 6 on the inner periphery of the cylinder at the same time. An oil tank 7a is arranged in the gap between the bearing 7 and the rotating shaft 6 between the other end side bearing 7 'to hold bearing oil.

  As a measure to prevent bearing oil scattering here, the difference from the conventional structure is that a spacer cap 2 that can contain the thrust washer 4 is newly installed, and between the eccentric weight 3 and the bearing 7, more precisely, the eccentric weight 3 and the thrust washer 4 It is the point which is inserted between.

  FIG. 7 shows an external view (a) of the spacer cap 2 according to the present invention viewed from the axial direction, and an AA cross-sectional view (b) as its cross-sectional shape. As shown in FIG. 7, the spacer cap 2 has a substantially disk-shaped outer shape and a substantially concave dish shape with the eccentric weight side at the bottom, and has a through hole 2 b through which the rotary shaft 6 is inserted at the center. On the side of the dish-shaped receiving surface 2c, as shown in FIG. 8, there is provided a circular recess that encloses the thrust washer 4 in the thickness D direction. Further, a circular deep groove 2d is formed on the bottom side in the outer peripheral direction of the dish-shaped receiving surface 2c. Further, an annular space region E following the deep groove portion 2d is provided on the entire circumference between the circumferential portion of the thrust washer 4 and the inner circumferential surface of the spacer cap 2.

  In the present embodiment, the spacer cap 2 is formed by resin molding using an injection molding technique or the like, and corresponds to mass production including cost. Furthermore, the spacer cap 2 is formed of a resin molding material having low wettability compared to the material of the thrust washer 4.

  2 and 3 are partially enlarged views of the thrust sliding portion of the vibration motor with the spacer cap 2 attached thereto. 2 and 3, a description will be given of a single thrust washer 4. 2 (a) and 3 (c) show the state when the motor rotation operation is stopped, and FIGS. 2 (b) and 3 (d) show the state during the motor rotation operation. It is the schematic which shows a whirling state.

  The reference numerals in the figure indicate the eccentric weight 3, the thrust washer 4, the rotary shaft 6, the bearing 7, and the oil tank 7a, as in FIG. 1, and the thick arrows K1 to K5 in FIG. The flow is shown. In short, FIG. 3 (c) shows the flow of the bearing oil after stopping the motor rotation, and FIG. 3 (d) shows the direction of the bearing oil flow during the motor rotating operation.

  (A) and (b) in FIG. 2 are comparisons between when the motor is rotating and when it is stopped. As shown in FIG. 2 (b), due to the rotating operation W of the eccentric weight 3, the thrust washer 4 and Centrifugal force and thrust force (arrow V) are applied to the spacer cap 2 and brought together toward the eccentric weight side. The flow of the bearing oil at this time is indicated by thick line arrows K1 to K3 in FIG.

  As shown in FIG. 3 (d), when the motor rotates, the bearing oil replenished from the oil tank 7a due to centrifugal force, thrust force, vibration, movement of the sliding portion, etc. It starts in the direction K1, flows along the side of the rotating thrust washer 4, and flows out in the direction of the circumference K2. At this time, there is a space region E between the circumferential part of the thrust washer 4 and the inner circumferential surface of the spacer cap 2, and the bearing oil flows in the K3 direction through this gap, and finally dams with the deep groove 2d of the spacer cap 2. The bearing oil is retained and retained in the spacer cap 2 by being stopped.

  At this time, since the spacer cap 2 is formed of a resin molding material having low wettability with the bearing oil compared to the material of the thrust washer 4, the bearing oil is blocked by the spacer cap 2 and is placed on the thrust washer 4 side. After gathering, the flow does not advance further and circulates in the spacer cap 2 to reach an equilibrium state.

  Next, when the rotation of the motor is stopped, as shown in FIG. 3 (c), the bearing oil accumulated in the spacer cap 2 is transmitted to both side surfaces of the thrust washer 4 on the contrary to the K4 on the rotating shaft 6 side. Return to the direction and continue to flow in the K5 direction on the bearing 7 side, and the bearing oil returns to the original oil tank 7a side without scattering.

  As a result, it is possible to reliably prevent the bearing oil from splashing in the sliding portion of the bearing that occurs during the rotational operation of the vibration motor, and to stably hold the bearing oil in the bearing sliding portion. Stabilization of rotation and longer life are possible.

<Embodiment 2>
FIG. 4 shows a structural example of another vibration motor according to the embodiment of the present invention. The vibration motor 1 shown in FIG. 4 has a cylindrical coreless motor structure in which an eccentric weight 3 is attached to the output shaft side of the rotary shaft 6 as in the first embodiment. As shown in FIG. The substantially rectangular elastic body holder 100 attached to the outer periphery of the housing case 10 of the motor body is fitted into the housing-side holding frame assembly of the portable device, and the power supply terminal 5 of the terminal block 12 is electrically connected to the circuit board. This is a type of vibration generator that is press bonded. Note that the characteristics of the bearing structure of the vibration motor 1 are the same as those of the first embodiment, and thus the description thereof is omitted.

  As a measure to prevent bearing oil scattering in the second embodiment, the difference from the conventional structure is that a spacer cap 2 that can contain both thrust washers 4a and 4b is newly installed and is inserted between the eccentric weight 3 and the thrust washer 4a. This is substantially the same as in the first embodiment. The difference in structure between FIG. 1 of the first embodiment and FIG. 4 of the second embodiment is that the number of installed thrust washers 4a and 4b between the eccentric weight 3 disposed on the rotary shaft 6 and the bearing 7 is different. Only the difference.

  5 and 6 are partially enlarged views of the thrust sliding portion of the vibration motor with the spacer cap 2 attached thereto. 5 and 6, the one using two thrust washers 4a and 4b will be described. FIGS. 5 and 6 (a) and 6 (c) both show the state when the rotation of the motor is stopped, and FIGS. 5 (b) and 6 (d) show the state during the rotation of the motor. It is the schematic which shows a whirling state.

  The reference numerals in the figure indicate the eccentric weight 3, thrust washers 4a and 4b, the rotary shaft 6, the bearing 7 and the oil tank 7a, as in FIG. 1, and the thick arrows N1 to N5 in FIG. The oil flow is shown. FIG. 6 (c) shows the flow of bearing oil after the motor rotation is stopped, and FIG. 6 (d) shows the direction of the bearing oil flow during the motor rotation operation.

  FIG. 5 shows a comparison between the rotating operation and the stopping operation of the motor. As shown in FIG. 5B, the thrust washers 4a and 4b and the spacer cap 2 are separated by centrifugal operation by the rotating operation W of the eccentric weight 3. A force and a force in the thrust direction (arrow V) are applied and brought together to the eccentric weight side. The flow of the bearing oil at this time is indicated by thick line arrows N1 to N3 in FIG. 6 (d).

  As shown in FIG. 6 (d), when the motor rotates, the bearing oil replenished from the oil tank 7a due to centrifugal force, thrust force, vibration, movement of the sliding portion, etc. First, it flows in the N1 direction, travels on both side surfaces of the rotating thrust washers 4a, 4b, and flows in the circumferential side N2 direction. At this time, there is a space region E between the spacer cap 2 and the outer periphery of the thrust washer 4 circumference, and the bearing oil flows in the N3 direction through this gap, and finally it is dammed by the deep groove 2d of the spacer cap 2. As a result, the bearing oil is collected and held in the spacer cap 2.

  At this time, since the spacer cap 2 is formed of a resin molding material having low wettability compared to the material of the thrust washer 4, the bearing oil is dammed by the spacer cap 2 and gathers on the thrust washer 4 side. First, the flow does not advance, and the spacer cap 2 is in an equilibrium state. Also, by using two thrust washers, more bearing oil can be retained than when two thrust washers 4a and 4b are used, and in addition to the spacer cap 2 due to the rotational movement of the eccentric weight 3. It is possible to reduce the adverse effect of the rotating action.

  Next, when the rotation of the motor stops, as shown in FIG. 6 (c), the bearing oil accumulated in the spacer cap 2 is transmitted to both side surfaces of the thrust washers 4a and 4b on the contrary to the above. It returns to the N4 direction, and continues to flow in the N5 direction on the bearing 7 side, and returns to the original oil tank 7a side without scattering.

  As a result, it is possible to reliably prevent the bearing oil from splashing in the sliding portion of the bearing that occurs during the rotational operation of the vibration motor, and to stably hold the bearing oil in the bearing sliding portion. Stabilization of rotation and longer life are possible.

  The structure for preventing the bearing oil from splashing in the thrust sliding portion according to the present invention includes a flat vibration motor having a rotating shaft and a vibration generator with a built-in weight in addition to a cylindrical vibration motor having an eccentric weight attached to the rotating shaft. In addition, it can be applied to the thrust sliding portion, and an effect can be expected to prevent bearing oil scattering of a driving motor in which a gear or the like is arranged at the tip of the output shaft.

It is a whole sectional view showing an example of an embodiment of a vibration motor concerning the present invention. It is a partial expanded sectional view which shows an example of the oil scattering prevention structure of the vibration motor which concerns on this invention. It is a partial expanded sectional view which shows the direction of the flow of the bearing oil by the oil splash prevention structure of the vibration motor which concerns on this invention. It is a whole sectional view showing an example of other embodiments of a vibration motor concerning the present invention. It is a partial expanded sectional view which shows an example of the other oil scattering prevention structure of the vibration motor which concerns on this invention. It is a partial expanded sectional view which shows the direction of the flow of the bearing oil by the other oil scattering prevention structure of the vibration motor which concerns on this invention. The external view of the spacer cap used for the oil splash prevention structure of the vibration motor which concerns on this invention, and AA sectional drawing. Sectional drawing when combining the spacer cap and thrust washer which are used for the oil splash prevention structure of the vibration motor which concerns on this invention. It is a partial expanded sectional view which shows an example of the oil scattering prevention structure of the vibration motor in a prior art. It is a partial expanded sectional view which shows the direction of the flow of the bearing oil by the oil splash prevention structure of the conventional vibration motor. It is the schematic which shows the operation pattern of the vibration motor which attached the eccentric weight to the output rotating shaft. It is an external appearance perspective reference view of the vibration motor used for the embodiment concerning the present invention.

Explanation of symbols

1 Vibration motor
2 Spacer cap
2a Chamfering step
2b Through hole
2c Reception surface
2d deep groove
3 Eccentric weight
4, 4a, 4b, 4e Thrust washer
5 Power supply terminal
6 Rotating axis
7, 7 'bearing
7a Oil tank
8 Magnet
9 coils
10 Housing case
11 Rectification mechanism
12 Terminal block
100 holder

Claims (4)

A bearing portion located at one end of the output shaft side of the housing case body of the vibration motor having an eccentric weight attached to the rotation shaft;
A thrust washer that is inserted through a rotating shaft between the bearing portion and the eccentric weight;
In the thrust sliding part of the vibration generator comprising:
A vibration motor, wherein a spacer cap having a substantially concave dish shape is separately inserted on a rotating shaft between the eccentric weight and the thrust washer. The spacer cap has a substantially concave dish shape with an eccentric weight side serving as a bottom,
The dish-shaped receiving surface side has a circular depression containing a thrust washer in the thickness direction,
And a circle-shaped deep groove portion is formed on the bottom side in the outer peripheral direction of the dish-shaped receiving surface,
Furthermore, between the circumferential portion of the thrust washer and the inner circumferential surface of the spacer cap,
The vibration motor according to claim 1, wherein an annular gap region following the deep groove portion has an internal shape provided on the entire circumference. The vibration motor according to claim 2, wherein the spacer cap is formed by resin molding. The vibration motor according to claim 3, wherein the spacer cap is formed of a resin molding material having low wettability with a bearing oil as compared with a thrust washer.

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