JP2002364636A - Thrust bearing structure and thrust plate manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust bearing structure capable of preventing the generation of partial abrasion and noise by preventing the assembling of a thrust plate in the condition that the thrust plate is inclined. SOLUTION: A ball 16 is arranged between a bottom part 22 of a housing 12 and a rotary shaft 14 supported by the housing 12. A first thrust plate 17 for abutting on the ball 16 is fitted in a first thrust plate housing recessed part 24 provided in the bottom part 22. A level difference part 33 is annular formed in the peripheral edge of a first surface 31 of the nearly disk-like first thrust plate 17, and a part surrounded by the level difference part 33 is formed into a central flat surface part 31a. A surface 34 positioned in the level difference part 33 and directed in the nearly same direction with the central flat surface part 31a is recessed to a second surface 32 side opposite to the first surface 31 by the height H of the level difference part 33. The level difference part 33 is formed with the hinge H larger than a projection quantity of a burr 37 generated outside in the radial direction of the surface 34 when blanking the first thrust plate 17 from a plate raw material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thrust bearing structure and a method for manufacturing a thrust plate.

[0002]

2. Description of the Related Art Motors, for example DC with worm reducer
There is a structure using a steel ball to receive a load applied in the thrust direction of the armature when the motor operates.

For example, in a thrust bearing structure disclosed in Japanese Patent Application Laid-Open No. Hei 3-181610, as shown in FIG.
Is provided with a concave portion 82 at the end face thereof, and a steel ball 83 is provided therein.
Is inserted. In order to prevent abrasion due to the contact with the steel ball 83, a steel plate 85 and a steel plate 85 are provided between the bottom of the recess 82 and the steel ball 83 and between the steel ball 83 and the bottom of the housing 84, respectively.
The thrust load is received with the intervening member 86. The steel plates 85 and 86 are formed by stamping a steel plate into a predetermined shape.

[0004]

However, when a steel plate is punched, the steel plates 85 and 86 have
Burrs occur on the periphery of one surface. When the steel plates 85 and 86 are arranged such that the burrs face the bottom of the recess 82 and the bottom of the housing 84, the steel plates 85 and 86 are often inclined. Due to the inclination of the steel plates 85 and 86, the steel balls 83
When a thrust load is applied at the contact point of, a component force is generated in the other direction from the thrust direction,
There is a possibility that uneven wear may be caused, which may cause abnormal noise.

In order to avoid the above problem, there is a method of disposing the steel plates 85 and 86 such that the surface on which the burrs are formed faces the steel ball 83.
However, it is necessary to distinguish between the burrs formed on the steel plates 85 and 86 and the surface on the opposite side when assembling, and the identification is extremely difficult and complicated. or,
Since the steel plates 85 and 86 are small parts, there is a problem that deburring is difficult and the cost increases.

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent the thrust plate from being assembled in an inclined state, thereby preventing uneven wear and generation of abnormal noise. An object of the present invention is to provide a thrust bearing structure and a method of manufacturing a thrust plate suitable for the thrust bearing structure.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a radial load held by a housing is supported by a radial bearing, and the radial load of the rotary shaft is supported. A thrust bearing structure for a rotating shaft in which a ball is interposed between an end surface and a thrust plate held by the housing to support a thrust load on the rotating shaft, wherein the ball is a protruding end of the rotating shaft. The thrust plate has a step portion such that a plane portion at the center of the thrust plate protrudes from a surface of a peripheral portion thereof.

According to the present invention, even when burrs are formed on the peripheral edge portion when forming the thrust plate, the burrs may protrude outside the central flat portion in the thickness direction of the thrust plate. It is prevented by this step. Therefore, it is possible to prevent the thrust plate from being inclined and assembled with respect to the plane where the thrust plate is disposed on the housing, thereby preventing uneven wear and noise. or,
In assembling the thrust plate, it is possible to assemble without considering the direction of the front and back.

According to a second aspect of the present invention, the radial load of the rotary shaft is supported by the radial bearing held by the housing, and a ball and a thrust plate are provided between the end surface of the rotary shaft and the housing. A thrust bearing structure for a rotating shaft in which the thrust load of the rotating shaft is interposed, wherein the thrust plate is held at a protruding end of the rotating shaft, and the thrust plate is provided at a center of the thrust plate. The gist of the present invention is to have a step so that the flat portion protrudes from the surface of the peripheral portion.

According to the present invention, the thrust plate includes:
Similarly to the thrust plate according to the first aspect of the present invention, even if burrs are formed on the peripheral edge when forming the thrust plate, the burrs protrude outward from the central flat portion in the thickness direction of the thrust plate. Is prevented by this step. Therefore, the thrust plate is prevented from being assembled with an inclination with respect to the plane of the thrust plate arrangement portion of the rotating shaft, and uneven wear and abnormal noise are prevented from occurring. Further, in assembling the thrust plate, the assembling can be performed without being conscious of the front and back directions.

According to a third aspect of the present invention, in the first or second aspect of the invention, the thrust plate is provided between the ball and the housing and between the protruding end of the rotating shaft and the ball. It is the gist that it is arranged in both in between. According to the present invention, since the wear of the portions in contact with the balls on both the rotating shaft side and the housing side is prevented by the thrust plate, it is possible to contribute to prolonging the life of the rotating shaft and the housing.

According to a fourth aspect of the present invention, in the second or third aspect, the thrust plate is fixedly arranged in a recess formed in an end face of the rotary shaft. And According to the present invention, it is possible to make the protruding end portion of the rotating shaft substantially the same as the state where the protruding end portion of the rotating shaft is hardened by performing the quenching process without increasing the axial length of the rotating shaft.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the step portion is formed by groove processing. According to the present invention, the step portion can be easily formed by groove processing, and the thickness of the thrust plate can be formed to be less than or equal to the thickness of the plate material.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the step portion has a concave portion formed on a surface opposite to the central flat portion. ,
The gist is that the projection having the central flat portion is formed by a projection forming process in which the projection is formed by plastic flow. According to the present invention, the hardness of the thrust plate can be improved by work hardening because the material of the plate material is plastically flowed.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a thrust plate, wherein a thrust load of a rotating shaft is interposed when the thrust load is supported by a ball. Forming a central plane portion with the portion to be formed as a central plane portion, and after the central plane portion forming step, pressing the annular groove portion including the central plane portion of the plate material to form the annular groove portion A cutting step of forming the thrust plate by cutting the entire plate material at the cutting step.In the cutting step, the annular groove portion including the central flat portion of the plate material is formed over the entire plate material. On the other hand, the gist of the present invention is to press the plate material in a direction in which the plate material is relatively moved toward the opposite side of the groove forming surface.

According to the present invention, the portion in which the groove is formed becomes the step, and the thrust plate according to the fifth aspect is manufactured. Also, during pressing in the cutting step, burrs may be formed on the peripheral portion in a protruding manner. However, due to the presence of the stepped portion, the burr is prevented from protruding outward in the thickness direction of the thrust plate from the central flat portion.

An eighth aspect of the present invention is a method for manufacturing a thrust plate which is interposed when a thrust load of a rotating shaft is supported by a ball, wherein a recess is formed in a plate material and the recess is formed by plastic flow. On the opposite side, a flat projection forming step of forming a flat projection, and after the flat projection forming step, including the projection of the plate material by pressing around the circumference of the projection. And a cutting step of cutting off a portion from the entire plate material. In the cutting step, a portion including the protrusion of the plate material is moved relative to the entire plate material toward the recess. The point is to press in the direction.

According to the present invention, the projection is formed by plastic flow by forming the recess in the step of forming the flat projection. Next, in the cutting step, the portion including the protrusion is cut from the entire plate material, and the portion around the protrusion becomes a step, and the thrust plate according to claim 6 is manufactured. During the press in the cutting step, burrs may be formed on the peripheral portion in a protruding manner. However, due to the presence of the step,
This burr is prevented from protruding outward from the plane of the projection in the thickness direction of the thrust plate.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a first embodiment in which the present invention is embodied in a thrust bearing structure for a rotating shaft of a motor will be described.
Will be described with reference to FIGS.

FIG. 1A is a schematic cross-sectional view of a motor bearing structure, and FIG. 1B is a schematic enlarged view of a main part.
(C) is a schematic enlarged view of the step portion. FIG. 3 is a schematic cross-sectional view of a main part in a state where the thrust plate is mounted on the rotating shaft with the direction of the thrust plate reversed.

As shown in FIG. 1A, the motor 11 is provided with a housing 12, an armature 13, a rotating shaft 14, a radial bearing 15, a ball 16, and first and second thrust plates 17, 18. .

The housing 12 is formed in a substantially cylindrical shape with a bottom, and a magnet 21 is attached to an inner peripheral surface thereof. A radial bearing holding portion 23 is formed on the bottom portion 22 of the housing 12, and a first thrust plate housing concave portion 24 is formed further on the center side than the radial bearing holding portion 23.

The first thrust plate receiving recess 24 has a first
The thrust plate 17 is fitted. Further, the radial bearing 15 is held in the radial bearing holding portion 23 by a bearing holding member such as a lock washer WA.
The radial bearing 15 has a ball receiving recess 25 and a rotating shaft through-hole 26 formed therein. The ball accommodating recess 25 communicates with the rotating shaft through hole 26, and the ball accommodating recess 25 is formed to have a larger diameter than the rotating shaft through hole 26. The ball 16 is housed in the ball housing recess 25. The ball 16 is a metal ball, and in this embodiment, is a steel ball. The ball 16 is in contact with the first thrust plate 17.

The rotary shaft 14 is inserted through the rotary shaft through hole 26. The rotating shaft 14 can come into contact with the radial bearing 15 around the rotating shaft through hole 26. The radial load of the rotating shaft 14 is applied to the housing 12 via the radial bearing 15.
It is configured to be received by. The rotation shaft 14
Is rotated integrally with the armature 13.

A second thrust plate housing recess 28 is formed on the end surface of the rotating shaft 14. The second thrust plate 18 is press-fitted into the second thrust plate accommodating concave portion 28, and the protruding end portion 14a near the end surface of the rotating shaft 14 (FIG.
(See (b)) holds the second thrust plate 18. The first and second thrust plates 17, 18 are metal thrust plates, and in this embodiment, are steel plates. The second thrust plate 18 is in contact with the ball 16. In this embodiment, the thrust bearing structure is configured such that the thrust load of the rotating shaft 14 is received by the housing 12 via the second thrust plate 18, the ball 16, and the first thrust plate 17.

As shown in FIG. 1B, the first thrust plate 17 is formed in a substantially disc shape, and has one surface (first surface).
31 and a surface (second surface) 32 opposite to the first surface 31. A step portion 33 is formed in an annular shape at a peripheral portion of the first surface 31. The first surface 31 has a portion surrounded by the step portion 33, the central flat portion 3 serving as a central flat portion.
1a. The central plane portion 31a and the second surface 32 are each formed in a plane, and are formed substantially parallel to each other. The peripheral surface 34 located at the step portion 33 and facing in the same direction as the central flat portion 31 a has a height H of the step portion 33.
Only (see FIG. 1 (c)), it is retracted from the central plane portion 31a to the second surface 32 side.

In the state shown in FIG. 1, the second surface 32 is in contact with the bottom surface 36 of the first thrust plate housing recess 24. The central flat portion 31a is in contact with the ball 16 at the center.

As shown in FIGS. 1B and 1C, the surface 34
In some cases, a burr 37 may be formed on a radially outer portion of the first thrust plate 17. The burrs 37 are generated when the first thrust plate 17 is formed by punching out a plate material. The burr 37 is used for the first thrust plate 17.
Project in the thickness direction. The step portion 33 has the height H,
The projection is formed so as to be larger than the assumed projection amount of the burr 37. Therefore, even if the burr 37 occurs, the burr 37 is retracted from the central plane portion 31a toward the second surface 32 (does not protrude from the central plane portion 31a).

As shown in FIG. 1B, the second thrust plate 18 is formed in a shape having a step like the first thrust plate 17, and has a smaller diameter than the first thrust plate 17. I have. Specifically, the second thrust plate 18 includes one surface (first surface) 41 and a surface (second surface) 42 opposite to the first surface 41, and is provided on a peripheral portion of the first surface 41. Has a step portion 43 formed in an annular shape.
On the first surface 41, a portion surrounded by the step portion 43 is a central flat portion 41a as a central flat portion.
The peripheral surface 44 located at the step portion 43 and facing in the same direction as the central flat portion 41 a is recessed from the central flat portion 41 a toward the second surface 42 by the height of the step portion 43.

In the state shown in FIG. 1, the second surface 42 is in contact with the bottom surface 46 of the second thrust plate housing recess 28, and the central flat portion 41a is in contact with the ball 16 at the center. In this embodiment, the bottom surface 46 corresponds to the end surface of the rotating shaft 14.

A burr 47 may be formed on the surface 44 at a radially outer portion of the second thrust plate 18. The step portion 43 is formed so that the height is larger than the expected protrusion amount of the burr 47, so that even if the burr 47 occurs, the step portion 43 is retracted toward the second surface 42 from the central flat portion 41a. (They do not protrude from the central flat portion 41a).

Next, a method of manufacturing the above thrust plate will be described. FIG. 2 shows a method for manufacturing a thrust plate, and FIG. 2A shows a schematic cross-sectional view of a plate material. FIG. 2B is a schematic plan view showing a state in which an annular groove is formed, and FIG. 2C is a schematic sectional view of the same.
(D) shows a schematic sectional view of the punching step.

Since the manufacturing method of the first thrust plate 17 and the second thrust plate 18 is the same, only the method of manufacturing the second thrust plate 18 will be described here.

First, as shown in FIG. 2A, a flat plate material 51 is prepared. And plate material 5
The first surface 52 (upper surface in FIG. 2A) of FIG.
An annular groove 53 is formed as shown in FIGS.
The groove 53 has an inner diameter substantially equal to the diameter of the central flat portion 41 a and a depth substantially equal to the height of the step portion 43.
Due to the formation of the groove 53, a portion of the first surface 52 surrounded by the groove 53 becomes a circular central flat portion 41a.

Next, the plate material 5 is placed on the first die 54.
The plate material 51 is placed so that the first surface 52 of the first plate 52 and the second surface 55 on the opposite side are in contact with each other. On the end face of the first punch 56, a concave portion 57 that fits with the central flat portion 41a is formed, and the plate material 51 is aligned with a predetermined position so that the concave portion 57 and the central flat portion 41a face each other. The first
On the die 54. Next, as shown in FIG. 2D, the first punch 56 is moved from the first surface 52 side, which is the surface on which the groove 53 of the plate material 51 is formed, to the second surface 55 side, and Punch 51. Plate material 51
The first punch 56 punches out a portion inside the outer peripheral portion of the groove 53. The punched portion becomes the second thrust plate 18, and the portion where the groove 53 is located becomes the step portion 43. The bottom surface 58 of the groove 53 becomes the surface 44.

When punched by the first punch 56, a burr 47 may be formed on the surface 44 at a radially outer portion. The burr 47 is dragged by a portion outside the punched portion of the plate material 51 or a wall surface of the punch receiving hole 54a of the first die 54, so that the burr 47 is moved in a direction opposite to the direction in which the first punch 56 moves ( It is formed so as to protrude from the second surface 42 side toward the central plane portion 41a).
However, since the groove 53 is formed in advance with a depth larger than the expected amount of projection of the burr 47, the burr 47 is formed in a state of being retracted from the central flat surface portion 41a to the second surface 42 side.

As described above, the step of forming the groove 53;
The second thrust plate 18 is formed from the plate material 51 by the punching process. Similarly to the second thrust plate 18, the first thrust plate 17 is also formed by a groove forming step and a punching step.

Next, the operation of the bearing structure configured as described above will be described. In the case shown in FIG. 1, since the second thrust plate 18 is press-fitted into the second thrust plate housing recess 28 in a state where the second surface 42 and the bottom surface 46 are in contact with each other, the second thrust plate 18 does not tilt with respect to the bottom surface 46. The second
The thrust plate 18 includes the ball 16 and the central flat portion 41.
Since the contact is made at the center of “a”, the step portion 43 and the burr 47 do not relate to the contact between the central flat portion 41 a and the ball 16.

Further, as shown in FIG. 3, the second thrust plate 18 may be attached to the rotating shaft 14 in a direction opposite to the case shown in FIG. In this case, the second thrust plate 18 is pressed into the second thrust plate housing concave portion 28 in a state where the central flat surface portion 41a and the bottom surface 46 are in contact with each other, and is in contact with the ball 16 at the center of the second surface 42.

The burr 47 is located on the central plane portion 4 with respect to the surface 42.
Since the central flat portion 41a is formed on the surface 44 lower than the surface 44 of the step portion 43 by the height of the step portion 43 than the surface 44 of the step portion 43, the central flat portion 41a is formed. It is retracted from the flat part 41a to the second surface 42 side. For this reason, the second thrust plate 18 does not contact the burr 47 with the bottom surface 46, and
1a is pressed into the second thrust plate housing recess 28 in a stable state by contacting the bottom surface 46. Therefore, the second thrust plate 18 is not affected by the burr 47,
Is prevented from being assembled in an inclined state with respect to.

As described above, the second thrust plate 18
Which of the central plane portion 41a and the second surface 42
6 and the second thrust plate receiving recess 28
Even if it is press-fitted, it can be prevented from being assembled in an inclined state. Further, like the second thrust plate 18, the first thrust plate 17 may be fitted into the first thrust plate housing recess 24 in any direction, but whichever of the central plane portion 31a and the second surface 32 is provided. Even if it is fitted into the first thrust plate housing recess 24 in a state in which it comes into contact with the bottom surface 36, it is prevented from being assembled in an inclined state.

The second thrust plate 18 may be press-fitted into the second thrust plate housing recess 28 in any direction. However, when the burr 47 is press-fitted in a direction facing the bottom surface 46 (see FIG. 3). In this case, the burr 47 may be caught on the peripheral edge of the second thrust plate housing recess 28. For this reason, when the second surface 42 and the bottom surface 46 are pressed into the second thrust plate housing recess 28 in a direction facing each other (the case shown in FIG. 1), the assembling property is improved. Similarly, the first thrust plate 17 is also provided with the first thrust plate 17 in either direction.
Although it may be fitted in the thrust plate housing recess 24,
When the second surface 32 and the bottom surface 36 face each other and are fitted into the first thrust plate housing recess 24 (as shown in FIG. 1), the assembling property is improved.

According to this embodiment, the following effects are obtained. (1) The second thrust plate 18 is provided with a plate material 5 on the periphery of the central flat portion 41a of the second thrust plate 18.
A step portion 43 having a predetermined height larger than the projection amount of the burr 47 generated when punching and forming from step 1 is formed.
Therefore, the surface 44 of the step portion 43 is lower than the surface 42 by the height of the step portion 43 than the central flat portion 41a. Therefore, the burrs 47 formed on the surface 44 are located in the central plane portion 41 a in the thickness direction of the second thrust plate 18.
It does not protrude outward. For this reason, the second thrust plate 18 is arranged such that the burr 47 and the bottom surface 46 face each other.
Is pressed into the second thrust plate housing recess 28 of the rotating shaft 14, the burr 47 does not contact the bottom surface 46. Therefore, the second thrust plate 18 can be press-fitted into the second thrust plate housing recess 28 so as not to be inclined, and uneven wear and generation of abnormal noise can be prevented.
Similarly, since the first thrust plate 17 also has the stepped portion 33, even when the burr 37 occurs, it can be fitted into the first thrust plate housing recess 24 so as not to be inclined.

(2) The second thrust plate 18 does not not only tilt when the second surface 42 opposite to the burr 47 faces the bottom surface 46, but also when the central flat portion 41a faces the bottom surface 46, A burr 47 is formed on the bottom surface 46 by the step 43.
Because it does not come into contact with the second thrust plate receiving recess 28 without being inclined. Therefore, the second thrust plate 18 can be press-fitted into the second thrust plate housing recess 28 of the rotating shaft 14 in any direction without considering the direction of the central flat portion 41a and the second surface 42. Similarly, the first thrust plate 17 also has a central flat portion 31a.
The first thrust plate housing recess 24 of the housing 12 can be fitted in either direction without considering the directions of the first and second surfaces 32.

(3) A first thrust plate 17 is disposed between the housing 12 and the ball 16,
A second thrust plate 18 is arranged between the protruding end portion 14a of the first and second balls 16 and the ball 16. Therefore, the burrs 37, 47
Of the housing 1 by the ball 16
Uneven wear of the shaft 2 and the rotating shaft 14 can be prevented, and the life of both the housing 12 and the rotating shaft 14 can be extended.

(4) The second thrust plate 18 is fixedly disposed in a second thrust plate housing recess 28 formed on the end face of the rotating shaft 14. Therefore, even if the material of the rotating shaft 14 is relatively soft, the portion in contact with the ball 16 on the rotating shaft 14 is substantially hardened by the second thrust plate 18 without increasing the axial length of the rotating shaft 14. Can be done.

(5) The step 43 can be easily formed by forming the groove 53 in the plate material 51. Also, the thickness of the thrust plate is
It can be formed as thin as the same thickness or less. Similarly,
The first thrust plate 17 can also easily form the step portion 33 by forming a groove in the plate material, and can be formed to be thinner than the thickness of the plate material.

(Second Embodiment) Next, a second embodiment will be described with reference to FIGS. In this embodiment,
The main difference from the above-described embodiment is that a concave portion is formed on the side opposite to the central plane portion of the thrust plate. The same parts as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. In the following, only the second thrust plate will be described, but the same applies to the first thrust plate.

FIG. 5 is a schematic cross-sectional view of a main part in a state where the second thrust plate of this embodiment is mounted on a rotating shaft.
As shown in FIG. 5, the second thrust plate 61 is formed with a flat cylindrical projection 63 protruding from the second surface 62 side toward the central plane portion 41a with the central plane portion 41a as an end face. . The periphery of the projection 63 is a step 43, and a burr 47 may be formed on the surface 44 of the step 43. The second thrust plate 61 has a second thrust plate.
A concave portion 64 is formed in the surface 62. The concave portion 64 is formed at a position corresponding to the central plane portion 41a, the bottom surface 65 of the concave portion 64 is formed in a circular shape having a diameter substantially equal to the diameter of the central planar portion 41a, and the depth of the concave portion 64 is The depth of the protrusion 63 is deeper than the protrusion amount of the protrusion 63. Second
The surface 62 has an annular flat portion 62 whose portion surrounding the recess 64 is annular.
a. No burr is formed on the annular flat portion 62a.

Next, a method of manufacturing the second thrust plate 61 will be described. FIG. 4 shows a method of manufacturing a thrust plate. FIG. 4A is a schematic cross-sectional view of a plate material, FIG. 4B is a schematic cross-sectional view of a step of forming a concave portion and a projection, and FIG. 4C is a schematic cross-sectional view of a punching step.

First, as shown in FIG. 4A, a flat plate material 71 is prepared. The plate material 71 has a first surface 72 and a second surface 73 that are parallel to each other. The thickness of the plate material 71 is smaller than the plate material 51 by the height of the protrusion 63.

As shown in FIG. 4B, the plate material 7
The first second surface 73 is pressed by the second punch 74, and the first surface 72 is pressed against the second die 75. Second punch 74
A protrusion 76 having the same diameter as the concave portion 64 and the same height as the depth of the concave portion 64 is formed on the end face. In addition, the end face of the second die 75 has the same diameter as the protrusion 63,
A recess 77 having the same depth as the height of the recess 77 is formed. For this reason, the plate material 71 is formed with the concave portion 64 in the second surface 73 by the pressing by the second punch 74 and the second die 75, and the first surface is formed by the plastic flow of the material of the plate material 71. A projection 63 is formed on 72. Due to the work hardening due to the plastic flow, the hardness of the portion of the plate material 71 extending from the concave portion 64 to the protrusion 63 is improved.

Next, the plate material 71 is brought into contact with the first die 54 such that the second surface 73 is brought into contact with the first die 54.
And the predetermined position is adjusted so that the projection 63 and the recess 57 of the first punch 56 face each other. And FIG.
As shown in (c), the first punch 56 is
The plate material 71 is punched by moving the plate material 71 from the side toward the second surface 73 to form the second thrust plate 61. A portion of the portion punched out of the plate material 71 by the first punch 56 around the protrusion 63 becomes the step 43 and the surface 44 is formed. Further, burrs 47 are generated on the radially outer portion of the surface 44.

In the state shown in FIG. 5, the second thrust plate 61 is press-fitted into the second thrust plate housing recess 28 with the annular flat portion 62a in contact with the bottom surface 46. Since no burr is formed on the annular plane portion 62a, the second thrust plate 61 is stably abutted without tilting with respect to the bottom surface 46. The second thrust plate 18 is in contact with the ball 16 at the center of the central flat portion 41a, and the step portion 43 and the burr 47 are not related to the contact between the central flat portion 41a and the ball 16.

A space 66 exists between the bottom surface 46 of the second thrust plate housing recess 28 and the bottom surface 65 of the recess 64. Therefore, when an impact force is applied to the bearing structure due to an external force or the like, the second thrust plate 61 protrudes into the space 66 using its own elasticity and is bent, so that the impact force is reduced.

Since the second thrust plate 61 has the concave portion 64, the first surface 41 and the second surface 62 can be easily distinguished. For this reason, as shown in FIG. 5, it is easy to press-fit the second thrust plate 18 into the second thrust plate housing recess 28 so that the annular flat portion 62a contacts the bottom surface 46.

Even when the second thrust plate 61 is pressed into the second thrust plate housing recess 28 so that the bottom surface 65 of the recess 64 faces the ball 16, the second thrust plate 61 is inclined by the burr 47. Assembly is prevented. However, depending on the relationship between the curvature of the ball 16 and the depth and diameter of the recess 64, the inner peripheral edge of the annular flat portion 62a may come into contact with the ball 16 and increase friction. In that case, the second thrust plate 61 is
4, the first surface 41 and the second surface 62 can be easily distinguished, so that the orientation shown in FIG. 5 can be easily identified, and can be pressed into the second thrust plate housing recess 28 in an appropriate orientation.

According to this embodiment, the following effects are obtained in addition to the effects (1), (3) and (4) of the first embodiment. (6) Since the concave portion 64 is formed in the second thrust plate 61, the first surface 41 and the second surface 62 can be easily identified. Therefore, the direction in which the annular flat portion 62a and the bottom surface 46 are in contact with each other can be easily identified, and the second thrust plate 61 can be pressed into the second thrust plate housing recess 28. Therefore, the second thrust plate 61 is pressed into the second thrust plate housing recess 28 in the opposite direction, thereby preventing the inner peripheral edge of the annular flat portion 62a from contacting the ball 16.

(7) Second punch 74 and second die 75
The plate material 71 is pressed by the second surface 73
A concave portion 64 is formed on the first surface 72 by plastic flow. Therefore, due to the work hardening due to this plastic flow, the second thrust plate 6
1 can be improved.

(8) Second thrust plate housing recess 28
Since the space 66 exists between the bottom surface 46 of the recess 64 and the bottom surface 65 of the concave portion 64, when an impact force is applied to the bearing structure by external force or the like, the second thrust plate 61 projects into the space 66 by utilizing its own elasticity. Can be bent. Therefore, the impact force can be reduced.

The embodiments are not limited to the above embodiments, but may be modified as follows, for example. -In 1st Embodiment, you may make the diameter of the center plane part 41a of the 2nd thrust plate 18 small. in this case,
The center plane portion 41a and the second surface 42 can be easily distinguished.
Therefore, the second surface 42 is in the second thrust plate housing recess 2.
The second thrust plate 18 can be assembled to the rotating shaft 14 by selecting only the direction in which the second thrust plate 18 comes into contact with the bottom surface 46. In this case, it is possible to prevent the burr 47 from being caught on the peripheral portion of the second thrust plate housing concave portion 28 at the time of assembling, and to improve the assembling property. Similarly, the first
The diameter of the central flat portion 31a of the thrust plate 17 may be reduced.

In the second embodiment, the diameter of the projection 63 of the second thrust plate 61 may be reduced. In this case, the first surface 41 and the second surface 62 of the second thrust plate 61 can be more easily distinguished.

The center plane portions 31a, 41a and the second surface of the first thrust plate 17, the second thrust plate 18, 61 and the second surface may be hardened by quenching with a laser or the like. In this case, wear can be further suppressed.

The second thrust plate 18 is provided on the rotating shaft 1
4 is not limited to being press-fitted into the second thrust plate housing recess 28, but is caulked by caulking the peripheral edge of the second thrust plate housing recess 28 while being pressed into the second thrust plate housing recess 28, for example. It may be fixed to the rotating shaft 14 by fixing.

Between the housing 12 and the ball 16;
The thrust plate is not limited to being disposed both between the protruding end of the rotating shaft 14 and the ball 16, and the thrust plate may be disposed only in one of the two. For example, the thrust plate may be disposed only between the housing 12 and the ball 16 and the ball 16 may be directly contacted with the end surface (protruding end) of the rotating shaft without forming the second thrust plate housing recess 28. . Further, the tip of the rotating shaft 14 and the ball 1
6 and the thrust plate is placed only between
May contact the housing 12 directly.

The ball 16 is not limited to a steel ball, and may be made of, for example, another metal having hardness equal to or higher than steel, ceramic, or the like. The first and second thrust plates 17, 18 are not limited to steel plates, but may be formed of other metals.

The second thrust plate 61 holds the ball 1
6, the bottom 65 of the recess 64 is pressed into the second thrust plate housing recess 28 so as to face the ball 16 at the center of the bottom 65 due to the relationship of the curvature of the recess 6, the depth of the recess 64, and the size of the diameter. There is a case where the ball 16 does not come into contact with the ball 16 at another portion such as the inner peripheral edge of the annular flat portion 62a merely by contacting the ball 16. In this case, the second thrust plate 61 may be press-fitted into the second thrust plate housing recess 28 without considering the directionality between the central flat portion 41a and the second surface 62.

The ball 16 is not limited to the configuration in which the ball 16 is housed in the ball housing recess 25 formed in the radial bearing 15. For example, as shown in FIG. A configuration in which a ball is accommodated in addition to the two thrust plates may be employed.

The technical ideas that can be grasped from the above embodiments will be additionally described below. (1) In the invention according to any one of claims 1 to 6, the thrust plate is subjected to laser hardening.

(2) In the invention according to claim 4,
The thrust plate is fixed in the recess of the rotating shaft by swaging.

[0071]

As described above in detail, according to the first to sixth aspects of the present invention, the thrust plate is prevented from being assembled in an inclined state, thereby preventing uneven wear and generation of abnormal noise. can do. Further, according to the seventh and eighth aspects of the present invention, it is possible to manufacture a thrust plate that can be prevented from being assembled in a tilted state, thereby preventing uneven wear and generation of abnormal noise.

[Brief description of the drawings]

FIG. 1A is a schematic sectional view showing a bearing structure of a motor,
(B) is a schematic enlarged view of a main part, and (c) is a schematic enlarged view of a step portion.

2A and 2B show a method of manufacturing a thrust plate, wherein FIG. 2A is a schematic sectional view showing a plate material, FIG. 2B is a schematic plan view showing a state in which an annular groove is formed, and FIG. (D) is a schematic sectional view showing a punching step.

FIG. 3 is a schematic cross-sectional view of a main part in a state where a thrust plate is assembled in an opposite direction.

FIG. 4 shows a method for manufacturing a thrust plate according to a second embodiment, in which (a) is a schematic cross-sectional view showing a plate material;
(B) is a schematic cross-sectional view showing a step of forming a concave portion and a projection,
(C) is a schematic sectional view showing a punching step.

FIG. 5 is a schematic cross-sectional view of a main part showing a state where the thrust plate is assembled.

FIG. 6 is a sectional view of a bearing structure to which a conventional thrust plate is assembled.

[Explanation of symbols]

12 ... housing, 14 ... rotating shaft, 14a ... protruding end, 1
5 ... radial bearing, 16 ... ball, 17 ... first thrust plate, 18, 61 ... second thrust plate, 28 ...
The second thrust plate housing concave portions as concave portions formed on the end surface of the rotating shaft, 31a, 41a... Central plane portions as central planar portions, 32, 42.
Surface, 33, 43: stepped portion, 44: peripheral surface, 46: bottom surface corresponding to the end surface of the rotating shaft, 51, 71: plate material, 52: first surface as a groove forming surface of the plate material,
53 ... groove, 63 ... projection, 64 ... recess.

Claims (8)

[Claims] 1. A radial bearing held by a housing supports a radial load of a rotating shaft, and a ball is interposed between an end face of the rotating shaft and a thrust plate held by the housing to rotate the rotating shaft. A thrust bearing structure for a rotating shaft in which a thrust load on the shaft is supported, wherein the ball is held at a protruding end of the rotating shaft,
A thrust bearing structure, wherein the thrust plate has a step portion such that a plane portion at the center of the thrust plate protrudes from a surface of a peripheral portion thereof. 2. A radial bearing of a rotary shaft is supported by a radial bearing held by a housing, and a ball and a thrust plate are interposed between an end surface of the rotary shaft and the housing so that the rotary shaft is mounted on the rotary shaft. A thrust bearing structure for a rotating shaft that supports a thrust load, wherein the thrust plate is held at a protruding end of the rotating shaft, and the thrust plate has a flat portion at the center of the thrust plate at a peripheral portion thereof. A thrust bearing structure having a stepped portion so as to protrude from a surface. 3. The thrust plate according to claim 1, wherein the thrust plate is disposed both between the tip of the rotating shaft and the ball and between the ball and the housing. The thrust bearing structure according to the above. 4. The thrust bearing structure according to claim 2, wherein the thrust plate is fixedly arranged in a concave portion formed on an end face of the rotation shaft. 5. The thrust bearing structure according to claim 1, wherein the step is formed by groove processing. 6. The step portion is formed by a projection forming process in which a recess is formed on a surface opposite to the central flat portion, and the projection having the central flat portion is formed by plastic flow. The thrust bearing structure according to any one of claims 1 to 4, wherein: 7. A method of manufacturing a thrust plate interposed when a thrust load of a rotating shaft is supported by a ball, wherein an annular groove is formed in a plate material, and a portion surrounded by the groove is a central plane. Forming a central flat portion, and after the forming the central flat portion, pressing the annular groove portion including the central flat portion of the plate material, and cutting off the entire plate material at the annular groove portion. A cutting step of forming the thrust plate by performing the cutting step. In the cutting step, the annular groove portion including the central flat portion of the plate material is formed with respect to the entire plate material with respect to the entire plate material. A method for manufacturing a thrust plate, wherein the pressing is performed in a direction of relative movement toward a side opposite to a surface on which the groove is formed. 8. A method of manufacturing a thrust plate interposed when a thrust load of a rotating shaft is supported by a ball, wherein a recess is formed in a plate material, and a flat surface is formed on a side opposite to the recess by plastic flow. A flat protrusion forming step of forming a protrusion; and after the flat protrusion forming step, a portion including the protrusion of the plate material is pressed by surrounding the periphery of the protrusion to press the entire plate material. A cutting step of cutting the plate material in the cutting step, wherein the portion including the projection of the plate material is pressed in a direction of relative movement toward the recess side with respect to the entire plate material. Thrust plate manufacturing method.