Bearing unit and motor with speed reducer

Abstract

The bearing unit (10) has: a thrust damper (20) capable of expanding and contracting in the axial direction of a shaft (2A) disposed in a gear case (4) and limited in movement to one side in the axial direction; a bearing receiving member (30) held to the thrust damper (20) from the other side in the axial direction of the thrust damper (20); a bearing bush retaining frame (50) holding the bearing receiving member (30) in a manner separable in the axial direction; and an oil-impregnated bearing bush (40) held to the bearing bush retaining frame (50) and disposed on the other side of the bearing receiving member (30). The thrust damper (20), the bearing receiving member (30), the bearing bush retaining frame (50), and the oil-impregnated bearing bush (40) are integrated before assembly to the gear case (4).

Description

Technical Field

[0001] This disclosure relates to a rotatable bearing unit that is mounted on a shaft within a gearbox, and a motor with a speed reducer that uses the bearing unit. Background Technology

[0002] Previously, motors with speed reducers were known for use in office equipment, vehicle electrical equipment, etc. In addition, it is known that in motors with speed reducers, multiple components such as bearings that support the shaft to rotate freely and dampers that limit the axial displacement of the shaft are used near the end of the shaft, which is disposed in a gearbox that houses the speed reduction mechanism (for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Publication No. 2000-510560 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the aforementioned motors with reducers, where multiple components such as bearings and dampers need to be handled separately, these components must be assembled sequentially within the gearbox. Therefore, issues arise that require confirmation of procedures or that the work becomes complex.

[0008] This application is made in view of the following problem, one of its objectives being to simplify the assembly steps of multiple components attached to a shaft disposed within a gearbox, making the assembly of these components easier. It should be noted that, not limited to this objective, another objective of this application is to achieve the effects derived from the structures shown in the detailed embodiments described below, and effects that cannot be obtained through existing technology.

[0009] Solution for solving the problem

[0010] (1) The bearing unit disclosed herein comprises: a thrust damper that is axially telescopic along a shaft disposed within a gearbox and is restricted to movement in one direction of the axial direction; a bearing coupling that is held to the thrust damper from the other side of the axial direction; a bearing retainer that holds the bearing coupling in a manner that allows it to be separated from the bearing coupling in the axial direction; and an oil-impregnated bearing that is held to the bearing retainer and disposed on the other side of the bearing coupling, wherein the thrust damper, the bearing coupling, the bearing retainer, and the oil-impregnated bearing are integrated before assembly into the gearbox.

[0011] (2) Preferably, the bearing retainer has a press-in end that is press-fitted into the receiving portion of the gearbox. In this case, it is preferable that the bearing assembly is lightly pressed into the bearing retainer before being assembled into the gearbox, and after being assembled into the gearbox, it is pressed against the axial side to release the lightly pressed-in state from the bearing retainer, and is held to slide freely relative to the bearing retainer in the axial direction.

[0012] (3) Preferably, the bearing assembly has: a damper-side press-in portion that presses into the inner bore of the cylindrical thrust damper; a flange portion that abuts against the other end face of the thrust damper; and a cage-side press-in portion that extends from the flange portion toward the other side and has a cylindrical surface. In this case, preferably, the bearing cage has: a press-in end that presses into and is fixed to a receiving portion of the gearbox; a protruding piece that extends from the press-in end toward one side and is lightly pressed in by the cylindrical surface of the cage-side press-in portion; and a retaining piece that extends from the press-in end toward one side and retains the oil-impregnated bearing, the oil-impregnated bearing being disposed on one side of the press-in end of the bearing cage.

[0013] (4) In the case of (3) above, it is preferable that the bearing assembly has a guide portion that extends from the cage-side press-in portion to the other side and has a cylindrical surface with a diameter smaller than that of the cage-side press-in portion. After the bearing assembly is assembled into the gearbox, the bearing assembly is pressed against the axial side to release the light press-in state with respect to the bearing cage and is held so that the guide portion can slide freely in the axial direction relative to the protrusion of the bearing cage.

[0014] (5) Preferably, the axial length of the retaining piece of the bearing retainer is shorter than the protruding piece of the bearing retainer, and the radial thickness is smaller than the protruding piece of the bearing retainer.

[0015] (6) In the case of (5) above, it is preferable that the press-in end of the bearing retainer has a positioning surface formed as a plane on a portion of its outer circumferential surface. In this case, it is preferable that the bearing retainer is configured such that, when pressed in and fixed in a state that matches the positioning surface with a predetermined position of the receiving portion, the protruding piece is positioned to bear the radial load acting on the shaft.

[0016] (7) Preferably, the bearing retainer has a plurality of the protruding tabs and a plurality of the retaining tabs. In this case, it is preferred that the protruding tabs and the retaining tabs are arranged alternately in the circumferential direction to form an inner circumferential surface surrounding the oil-impregnated bearing.

[0017] (8) Preferably, the press-in end of the bearing retainer is annular and has a shaft guide surface whose inner diameter gradually decreases from the end face on the other side toward the one side.

[0018] (9) Preferably, in a cross section in which the bearing retainer is cut along the axial direction, the portion of the protruding piece on the inner surface of the oil-impregnated bearing facing the press-in end side is curved along the outer peripheral surface of the oil-impregnated bearing, and the portion of the retaining piece on the inner surface of the oil-impregnated bearing facing the press-in end side extends along the axial direction without following the outer peripheral surface of the oil-impregnated bearing.

[0019] (10) Preferably, a shaft abutment portion abutting the shaft is formed on the end face of the other side of the bearing connector, the shaft abutment portion having a shape capable of accumulating grease.

[0020] In addition, the motor with a speed reducer disclosed herein includes: a motor part having a shaft; a speed reduction mechanism having a worm that rotates integrally with the shaft of the motor part and a worm wheel that meshes with the worm; and a gearbox that mounts the motor part and houses the speed reduction mechanism, wherein a bearing unit as described in any one of (1) to (10) above is applied to the end of the shaft disposed in the gearbox.

[0021] Invention Effects

[0022] According to the disclosed bearing unit and motor with reducer, the assembly steps of multiple components attached to the shaft can be simplified, and the assembly operation of these multiple components can be made easier. Attached Figure Description

[0023] Figure 1 This is a top view of the motor with a speed reducer according to the embodiment, showing the main parts in cross section.

[0024] Figure 2 yes Figure 1 An enlarged view of the X section (bearing unit).

[0025] Figure 3 It is shown Figure 2 A three-dimensional view of the bearing unit before it is assembled into the gearbox.

[0026] Figure 4 yes Figure 3 An exploded perspective view of the bearing unit.

[0027] Figure 5 It is from one side of the axial direction ( Figure 4 (Observe the direction of arrow B in the image) Figure 2 A diagram of the bearing cage of the bearing unit.

[0028] Figure 6 yes Figure 5 A three-dimensional view of the bearing cage.

[0029] Figure 7 It is used for explanation Figure 2 A diagram illustrating the function of the bearing unit.

[0030] Figure 8 It is used for explanation Figure 2 A diagram illustrating the function of the bearing unit. Detailed Implementation

[0031] Referring to the accompanying drawings, the bearing unit and the motor with a speed reducer, as embodiments, will be described. The embodiments shown below are merely illustrative and are not intended to exclude various modifications or technical applications not explicitly shown in these embodiments. The structures of this embodiment can be implemented through various modifications without departing from its main idea. Furthermore, selections and appropriate combinations can be made as needed.

[0032] [1. Structure]

[0033] Figure 1 This is a top view of the motor 1 (hereinafter referred to as "motor 1") with a speed reducer according to this embodiment, showing the main parts in cross-section. Figure 1 In this context, motor 1 is in a stationary state. Motor 1 is used, for example, in a vehicle's power window system. Figure 1 As shown, the motor 1 includes a motor unit 2 as a drive source, a speed reduction mechanism 3 that reduces the speed of the motor unit 2 and outputs the speed, and a gearbox 4 that houses the speed reduction mechanism 3.

[0034] The motor unit 2 has a shaft 2A extending toward the housing 2D and disposed within the gearbox 4. Hereinafter, the axial direction of the shaft 2A in the state where the motor unit 2 and gearbox 4 are engaged will be referred to as the "axial direction," and the direction in which the shaft 2A extends from the housing 2D (in...) will be referred to as the "axial direction." Figure 1 The direction to the left (center) is called "one side," and its opposite direction (in) is called "the other side." Figure 1 The direction to the right (in the middle) is referred to as the "other side". In this embodiment, the bearing unit 10 is applied to one end 2a of the shaft 2A. The bearing unit 10 supports the shaft 2A so that it can rotate freely and restricts the displacement of the shaft 2A.

[0035] Motor 2 is, for example, a brushed DC motor, having a rotor 2B and a stator 2C built into a housing 2D. The housing 2D is a bottomed cylindrical shape, and a flange 2E, provided around an opening (not shown), is connected to the gearbox 4 from the other side via a fastening member. Shaft 2A is the output shaft of motor 2, rotating integrally with the rotor 2B. The other end of shaft 2A is supported by the housing 2D.

[0036] The reduction mechanism 3 includes a worm 3A fixed to and rotating integrally with shaft 2A, and a worm wheel 3B having teeth that mesh with the worm 3A. The worm 3A is, for example, a threaded gear, and the worm wheel 3B is a helical gear that meshes with the worm 3A. An output gear 3C is connected to the worm wheel 3B, which drives the driven component by meshing with a gear disposed on the driven component.

[0037] The gearbox 4 is a housing that houses the shaft 2A, the worm 3A, and the worm wheel 3B. Inside the gearbox 4, a worm housing space S1 is formed to house the shaft 2A and the worm 3A, and a worm wheel housing space S2 is formed to house the worm wheel 3B. A portion that connects to the motor unit 2 is provided on the other side of the portion forming the worm housing space S1. Additionally, a connector 5 capable of supplying power to the motor unit 2 from the outside may be fitted into the portion forming the worm housing space S1. The worm housing space S1 and the worm wheel housing space S2 are interconnected at the meshing portion of the worm 3A and the worm wheel 3B.

[0038] Will Figure 1 Enlarged illustration of the X part at Figure 2 .like Figure 2 As shown, the gearbox 4 includes a receiving portion 4A that forms a bearing receiving space S3 that bulges out toward one side of the worm gear receiving space S1. The bearing unit 10 of this embodiment is received in this bearing receiving space S3. The receiving portion 4A has an end wall 4a (inner wall) that extends perpendicularly to the axial direction on one side, a generally cylindrical inner peripheral wall 4b that extends from the end wall 4a to the other side and is connected to the worm gear receiving space S1 side, and a press-in wall 4c located on the other side of the inner peripheral wall 4b.

[0039] The bearing retainer 50 of the bearing unit 10, described later, is pressed into and fixed to the press-in wall 4c. In this embodiment, the press-in wall 4c, except for a portion, is formed as a cylindrical surface with an inner diameter slightly larger than the inner diameter of the inner peripheral wall 4b, and a portion (specifically, a portion of the press-in wall 4c on the worm gear 3B side) is formed as a planar shape parallel to the axial direction. That is, when viewed from the axial direction, the press-in wall 4c has a shape in which a portion of a circle is cut off by a line segment. This planar portion (hereinafter referred to as the "planar portion") is at a predetermined position that matches the positioning surface 51f, described later.

[0040] Figure 3 This is a perspective view of the bearing unit 10 before it is assembled into the gearbox 4. Figure 4 This is an exploded perspective view of the bearing unit 10 (showing its state before assembly). Figures 2-4 As shown, the bearing unit 10 has multiple components 20, 30, 40, and 50, which are integrated into one unit before being assembled into the gearbox 4. Figure 3The state shown is that of a bearing assembly, in which it is assembled into the gearbox 4. That is, the assembly operation into the gearbox 4 can be performed in one step. It should be noted that the term "integration" here means that, at least during the assembly of the bearing unit 10 into the gearbox 4, the multiple components 20, 30, 40, and 50 will not detach from other components 20, 30, 40, and 50, and the relative positions of the multiple components 20, 30, 40, and 50 are fixed.

[0041] Furthermore, after the bearing unit 10 is assembled into the gearbox 4, the integrated state is decoupled by placing the shaft 2A on the gearbox 4, and multiple components 20, 30, 40, and 50 are arranged in predetermined positions. Hereinafter, unless otherwise specified, the description will assume that the bearing unit 10 and shaft 2A are assembled into the gearbox 4 and the motor 1 is stationary.

[0042] The bearing unit 10 includes a thrust damper 20 that abuts against the end wall 4a of the receiving portion 4A, and a bearing coupling 30 held in place of the thrust damper 20 from the other side. Additionally, the bearing unit 10 includes an oil-impregnated bearing shell 40 disposed on the other side of the bearing coupling 30, and a bearing shell retainer 50 that holds the bearing coupling 30 and the oil-impregnated bearing shell 40. These four components 20, 30, 40, and 50 are arranged coaxially side-by-side in the axial direction.

[0043] The thrust damper 20 is a cylindrical component made of a material that can expand and contract along the axial direction (e.g., rubber), with one end face 21 (hereinafter referred to as "one end face 21") abutting against the end wall 4a of the receiving portion 4A. It should be noted that the end wall 4a mentioned here is any component that, when the thrust damper 20 is pressed from the other direction along the axial direction, presses against a portion of the thrust damper 20 (e.g., one end face 21) to restrict the axial movement of the thrust damper 20; therefore, it is not limited to the inner wall of the gearbox 4, but can also be a stop or other part or component. That is, the thrust damper 20 may not necessarily abut against the gearbox 4 itself.

[0044] The thrust damper 20 has an inner hole 20h for pressing the bearing receiving component 30 into the damper-side press-in portion 31, which will be described later. In this embodiment, as... Figure 4 As shown, multiple ribs protruding radially inward are provided on the inner circumferential surface of the thrust damper 20, which forms the inner hole 20h. By providing these ribs, the bearing assembly 30 can be properly pressed into the damper-side pressing portion 31 relative to the thrust damper 20 to a degree that the bearing assembly 30 does not separate from the thrust damper 20 even after the bearing unit 10 is assembled to the gearbox 4. Furthermore, the outer diameter of the thrust damper 20 is set to be smaller than the inner diameter of the inner circumferential wall 4b of the receiving portion 4A. This creates a gap between the thrust damper 20 and the inner circumferential wall 4b of the receiving portion 4A.

[0045] The bearing connector 30 is a component held in the thrust damper 20 from the axial side of the thrust damper 20, and has a bearing surface 30f that abuts against the shaft 2A from one side. The bearing connector 30 serves to transmit the displacement of the shaft 2A in the thrust direction to the thrust damper 20, and also to integrate the bearing unit 10 with the bearing cage 50. The bearing connector 30 has a damper-side press-in portion 31 that presses into the inner hole 20h of the thrust damper 20, a flange portion 32 that abuts against the other end face (hereinafter referred to as "the other end face 22") of the thrust damper 20, and a cage-side press-in portion 33 that extends from the flange portion 32 to the other side. The bearing connector 30 of this embodiment also has a guide portion 34 that extends from the cage-side press-in portion 33 to the other side, forming a stepped shape with four portions of different outer diameters arranged side by side along the axial direction. To suppress damage and dust generation associated with the contact of shaft 2A, the bearing connection component 30 is made of a resin with high strength, rigidity, and wear resistance.

[0046] The damper-side press-in portion 31 is a press-in portion that makes the bearing connector 30 and the thrust damper 20 fit together (integral). The damper-side press-in portion 31 is cylindrical (e.g., cylindrical) with an outer diameter capable of pressing into the inner hole 20h of the thrust damper 20. The axial dimension of the damper-side press-in portion 31 is shorter than the axial dimension of the thrust damper 20, and, as... Figure 2 As shown, the length of the gap is set to form a small gap between the end face of the damper-side press-in portion 31 and the end wall 4a of the receiving portion 4A when the motor 1 is stationary. When the motor 1 is in motion, this gap is set to be smaller than the expected displacement, so that it can fully absorb the load and impact in the thrust direction of the shaft 2A.

[0047] The flange portion 32 is a generally circular plate-shaped portion with a diameter larger than that of the damper-side press-in portion 31, and its surface facing one side abuts against the other end face 22 of the thrust damper 20. The outer diameter of the flange portion 32 is formed to a sufficient size so that the flange portion 32 will not be embedded in the inner hole 20h when the bearing receiving member 30 is pressed in from the other direction of the axial direction by the shaft 2A, and is formed to be smaller than the inner diameter of the receiving portion 4A, for example, equal to the outer diameter of the thrust damper 20. Figure 4 As shown, in this embodiment, the flange portion 32 has a shape in which the outer peripheral portions of two parts offset by 180 degrees are cut off by line segments. For example, in the injection molding of the bearing connector 30, the portion cut off by the line segments can be formed by setting it at the gate position or by cutting it off.

[0048] The cage-side press-in portion 33 is a lightly press-in portion that temporarily brings the bearing assembly 30 and the bearing cage 50 into a fitted (integral) state. The cage-side press-in portion 33 has a cylindrical surface 33f, for example cylindrical, capable of lightly pressing into the protruding piece 52 of the bearing cage 50 (described later). The outer diameter of the cylindrical surface 33f of the cage-side press-in portion 33 is set to be smaller than the outer diameter of the flange portion 32. As described later, the lightly press-in state of the cage-side press-in portion 33 is released during the assembly of the shaft 2A.

[0049] The guide portion 34 is the portion that guides the bearing assembly 30 axially relative to the bearing retainer 50 after the light pressing state between the bearing assembly 30 and the bearing cage 50 is released. The guide portion 34 has a cylindrical surface 34f with a diameter smaller than the cylindrical surface 33f of the cage-side pressing portion 33, for example, it is cylindrical. Even after the light pressing state between the bearing assembly 30 and the bearing cage 50 is released, the bearing assembly 30 will not completely separate from the bearing cage 50 (will not fall off), and will remain coaxial through the guide portion 34.

[0050] In this embodiment, a shaft abutment portion 35 is formed on the other end face of the bearing connector 30, abutting against the shaft 2A. The shaft abutment portion 35 has a shape capable of accumulating grease. Here, the shaft abutment portion 35 will be described as a recess 35 partially recessed radially inward on the other end face of the guide portion 34. The aforementioned bearing surface 30f is provided in the recess 35.

[0051] The bearing surface 30f is preferably formed into a flat shape, and the end face of the shaft 2A that abuts against the bearing surface 30f is preferably formed into a spherical shape that protrudes relative to the bearing surface 30f. This reduces the contact area between the shaft 2A and the bearing surface 30f by point contact, thus suppressing wear and dust generation associated with the contact of the shaft 2A. Alternatively, by forming the bearing surface 30f into a spherical shape that protrudes relative to the end face of the shaft 2A, and forming the end face of the shaft 2A that abuts against the bearing surface 30f into a flat shape, the contact between the shaft 2A and the bearing surface 30f can also be made into point contact, thus achieving the same effect.

[0052] It should be noted that in the recess 35 of this embodiment, a groove is provided in a radially outer direction surrounding the receiving surface 30f. This groove functions as a grease reservoir for storing grease to improve lubricity and wear resistance, but it may be omitted. That is, the recess 35 can be a simple channel shape that opens to the other side, as long as it is shaped to store a small amount of grease. In addition, the receiving surface 30f may be concave, for example, in addition to convex or flat shapes.

[0053] The oil-impregnated bearing bush 40 is a ring-shaped general-purpose bearing component having an inner circumferential surface that can slide with the shaft 2A and an outer circumferential surface that is formed in a spherical shape. The oil-impregnated bearing bush 40 is impregnated with lubricating oil and rotates to support the shaft 2A in a central through hole.

[0054] In addition to retaining the oil-impregnated bearing shell 40, the bearing retainer 50 also serves to fix the bearing unit 10 within the receiving portion 4A, and as described above, to integrate the bearing unit 10 with the bearing connector 30, while retaining the bearing connector 30 in a manner that allows for axial separation. The bearing retainer 50 will now be described in detail.

[0055] Figure 5 It is from one side of the axial direction ( Figure 4 (Observe the top view of the bearing cage 50 in the direction of arrow B) Figure 6 It is from one side of the axial direction and the worm gear 3B side ( Figure 5 (See the perspective view of the bearing retainer 50 in the direction of arrow C). The bearing retainer 50 has a press-in end 51 of the press-in wall 4c of the press-in receiving portion 4A, and a protruding piece 52 and a retaining piece 53 extending axially from one end face of the press-in end 51. The bearing retainer 50 is made of resin, for example. This resin may be the same as the resin constituting the bearing connector 30, but since it does not abut against the shaft 2A as the bearing connector 30 does, and therefore requires the flexibility described later, a resin with superior flexibility to some extent is preferred compared to strength, rigidity, and wear resistance.

[0056] The press-in end 51 is the part that functions to fix the bearing unit 10 within the receiving portion 4A, and is annular in shape with a hole 51h on its radially inner side for the shaft 2A to pass through. For example... Figure 2 As shown, the inner circumferential surface 51a of the press-in end 51 forming the hole 51h has a shaft guide surface 51b, the inner diameter of which gradually decreases from one end face to the other. The shaft guide surface 51b is the surface that guides the insertion of the shaft 2A, and can be provided as a whole of the inner circumferential surface 51a, or it can be provided in the opposite part of the inner circumferential surface 51a. The shaft guide surface 51b can be formed by a conical surface, an R-surface, or a surface of other shapes capable of guiding the shaft 2A.

[0057] like Figure 5 As shown, the shape of the press-in end 51 corresponds to the shape of the press-in wall 4c of the receiving portion 4A. In this embodiment, since a flat portion is provided in the press-in wall 4c, the shape of the press-in end 51 is also the same (a shape in which a portion of a circle is cut off by a line segment when viewed from the axial direction). Figure 6As shown, a flat locating surface 51f is provided on the outer peripheral surface 51c that forms the shape of the press-in end 51. When the bearing unit 10 is arranged, this locating surface 51f matches the planar portion of the aforementioned receiving portion 4A. The locating surface 51f can be formed, for example, as a gate location during injection molding of the bearing retainer 50, or it can be formed by cutting it off. In addition, multiple ribs protruding radially outward are provided on the outer peripheral surface 51c in portions other than the locating surface 51f. When the bearing unit 10 is inserted into the receiving portion 4A, these ribs are pressed against the press-in wall 4c, thereby stably pressing and fixing the bearing unit 10 into the receiving portion 4A.

[0058] The protruding piece 52 functions as an integral part of the bearing unit 10 together with the bearing connector 30, while the retaining piece 53 functions as a part that retains the oil-impregnated bearing shell 40. For example... Figure 5 As shown, when viewed axially, both the protruding piece 52 and the retaining piece 53 are arc-shaped, forming an inner circumferential surface surrounding the oil-impregnated bearing shell 40. In this embodiment, a bearing shell retainer 50 with three protruding pieces 52 and three retaining pieces 53 is exemplified. The three protruding pieces 52 and three retaining pieces 53 are alternately arranged circumferentially, separated from each other, surrounding the central hole 51h. The protruding pieces 52 have the same shape but different configurations (phases). The retaining pieces 53 also have the same shape but different configurations (phases). It should be noted that it is preferable that each protruding piece 52 and each retaining piece 53 surrounds the central hole 51h, and adjacent pieces are arranged at equal intervals in the circumferential direction, so that the retaining force of the oil-impregnated bearing shell 40 and the force applied to the shaft 2A are not biased.

[0059] like Figure 2 As shown, the axial length of the protruding piece 52 is longer than that of the retaining piece 53. Therefore, on one side of the front end of the retaining piece 53 and the radially inner side (oil-containing bearing shell 40 side) surrounded by the front end portion of the protruding piece 52, a space is formed that allows the retainer-side press-in portion 33 and the guide portion 34 of the bearing connecting member 30 to be inserted. The front end side (one side) of the inner circumferential surface 52f (the surface facing the radially inner side) of the protruding piece 52 is shaped to form a cylindrical surface 33f that can be lightly pressed into the retainer-side press-in portion 33 of the bearing connecting member 30. In addition, in a cross-section that cuts along the axial direction of the bearing shell retainer 50, the base end side (press-in end 51 side) of the inner circumferential surface 52f of the protruding piece 52 is formed to form a curved surface that bends along the spherical outer circumferential surface of the oil-containing bearing shell 40. As a result, the bearing retainer 50 also makes surface contact with the oil-impregnated bearing 40 at the base end of the inner circumferential surface 52f of the protruding piece 52, thus enabling the oil-impregnated bearing 40 to be held without wobbling.

[0060] Additionally, one of the three protruding pieces 52 is positioned to bear the radial load acting on shaft 2A. The reaction force (radial load) of the gear generated between worm gear 3B and worm 3A originates from... Figure 2 The lower part acts upward on the shaft 2A of this embodiment. Therefore, one of the three protruding pieces 52 is arranged in... Figure 2 On the upper side, in other words, it is positioned 180 degrees phase-off (radially opposite) relative to the positioning surface 51f of the press-in end 51. That is, the bearing retainer 50 is formed such that, when pressed and fixed in a state that aligns the positioning surface 51f with a predetermined position of the receiving portion 4A, the protruding piece 52 is positioned to bear the radial load acting on the shaft 2A. In order to reliably bear this radial load, the protruding piece 52 is preferably formed to be thicker or coarser and more rigid (not easily bent) than the retaining piece 53.

[0061] The radial thickness of the retaining piece 53 is smaller than that of the protruding piece 52, and a claw portion 53a protruding radially inward is provided at its front end. The oil-impregnated bearing 40 held in the bearing retainer 50 is prevented from falling off to one side of the axial direction by the claw portion 53a. The radial thickness of the retaining piece 53 is set to a thickness that generates a bending moment that does not hinder the rotation of the oil-impregnated bearing 40 disposed radially inward. Thus, the retaining piece 53 allows the rotation of the oil-impregnated bearing 40 and retains the oil-impregnated bearing 40. In a cross-section that cuts the bearing retainer 50 axially, the portion of the base end side (press-in end 51 side) of the inner circumferential surface 53f (the surface facing radially inward) of the retaining piece 53 does not extend axially along the spherical outer circumferential surface of the oil-impregnated bearing 40. In other words, the base end portion of the inner circumferential surface 53f of the retaining piece 53 extends axially along the spherical outer circumferential surface of the oil-impregnated bearing 40. Figure 2 It forms a flat shape in the cross-section shown.

[0062] [2. Function]

[0063] Reference Figure 2 , Figure 3 , Figure 7 and Figure 8 The function of the bearing unit 10 described above will be explained. The bearing unit 10 is assembled into the gearbox 4 after integrating components 20, 30, 40, and 50. Then, by inserting and positioning the shaft 2A into the gearbox 4, the bearing unit 10 releases the bearing connector 30 from its state of being lightly pressed into the bearing shell retainer 50, and components 20, 30, 40, and 50 are positioned in their designated locations. Thus, the bearing unit 10 is in a state where it can perform its function.

[0064] The specific steps are explained below. First, before assembling into the gearbox 4, the oil-impregnated bearing shell 40 is inserted into the radially inner side of the protruding piece 52 and the retaining piece 53 of the bearing shell retainer 50, and held so that it can rotate freely relative to the bearing shell retainer 50. Next, the damper-side press-in portion 31 of the bearing connector 30 is pressed into the inner hole 20h of the thrust damper 20. Then, the retainer-side press-in portion 33 of the bearing connector 30 is gently pressed into the protruding piece 52 of the bearing shell retainer 50, which holds the oil-impregnated bearing shell 40. Thus, as... Figure 3 As shown, the components 20, 30, 40, and 50 of the bearing unit 10 are integrated as a single assembled bearing and are assembled into the gearbox 4 in this state. It should be noted that grease is pre-applied to the recess 35 of the bearing receiving component 30 before assembly into the gearbox 4, or grease is applied after assembly.

[0065] Figure 7 This diagram shows the state before the bearing unit 10 is assembled into the gearbox 4 and the shaft 2A is installed.

[0066] The integrated bearing unit 10 is assembled to the gearbox 4 by pressing the press-in end 51 of the bearing retainer 50 into the press-in wall 4c of the gearbox 4. At this time, the press-in end 51 of the bearing retainer 50 is configured such that its positioning surface 51f faces the flat portion of the press-in wall 4c. In other words, the bearing unit 10 is positioned with its positioning surface 51f facing... Figure 7 The lower side of the bearing is inserted into the receiving portion 4A, and the press-in end 51 is pressed into the press-in wall 4c for positioning and configuration. Thus, a protruding piece 52 of the bearing retainer 50 is positioned to bear the radial load acting on the shaft 2A. Figure 7 (The upper side). The interior of the housing 4A is difficult to see from the outside, making it difficult to fix the bearing unit 10 in the proper position. However, due to the presence of the positioning surface 51f, the press-in end 51 can only be pressed into the press-in wall 4c in the proper position. Therefore, press-in fixation is always achieved only in the proper position, which can suppress the occurrence of installation errors, etc.

[0067] After assembling the bearing unit 10 into the gearbox 4, as follows Figure 2 As shown, shaft 2A is inserted into gearbox 4. At this time, shaft 2A is guided into hole 51h by shaft guide surface 51b of bearing retainer 50, passing sequentially through hole 51h of bearing retainer 50 and through hole of oil-impregnated bearing 40, and abutting against bearing contact surface 30f of bearing assembly 30. Then, shaft 2A is pressed into one axial direction, pressing bearing assembly 30. This pushes the retainer-side pressing portion 33 of bearing assembly 30 out of protruding piece 52 of bearing retainer 50, releasing the lightly pressed-in state between the two. That is, simply by assembling motor part 2 on gearbox 4, without any special operation or additional steps, the lightly pressed-in state between bearing assembly 30 and bearing retainer 50 is naturally released.

[0068] Therefore, the bearing housing 30 is axially held to slide freely relative to the bearing retainer 50. Specifically, the guide portion 34 of the bearing housing 30 is held in a core-like shape relative to the protruding piece 52 so that it will not detach from the protruding piece 52 even when the shaft 2A is mounted on the gearbox 4. Thus, the radial positions of the bearing retainer 50 and the bearing housing 30 do not shift, maintaining a coaxial state. Even when the bearing housing 30 is pressed into its structurally maximum extent by the shaft 2A, the guide portion 34 will not detach from the protruding piece 52, maintaining this coaxial state.

[0069] Furthermore, at this time, the thrust damper 20 is pressed into one side by the bearing connector 30. This creates a balance between the force exerted by the bearing connector 30 being pressed into one side by the shaft 2A and the reaction force of the thrust damper 20. It should be noted that when the thrust damper 20 is pressed into one side, it deforms by shrinking axially while expanding radially outward. However, even if the amount of pressure exerted by the bearing connector 30 increases according to the driving state of the motor 1, and the expansion of the thrust damper 20 increases, the deformation of the thrust damper 20 is not hindered by the inner peripheral wall 4b because a gap is formed between the thrust damper 20 and the inner peripheral wall 4b as described above.

[0070] As described above, the bearing unit 10 assembled in the gearbox 4 supports the end 2a of the shaft 2A so that it can rotate freely. In addition, the bearing unit 10 performs the functions of self-aligning and limiting the displacement of the shaft 2A according to the drive of the motor 1.

[0071] Specifically, the bearing unit 10 allows the oil-impregnated bearing 40, which is rotatably held in the bearing cage 50, to tilt at a predetermined angle relative to the axis of the bearing cage 50, thereby achieving automatic self-alignment by utilizing the rotation of the shaft 2A. Additionally, when the motor 1 drives the driven component, the reaction force (radial load) of the gear generated between the worm 3A and the worm wheel 3B sometimes acts on the shaft 2A. In this embodiment, this radial load originates from... Figure 2 The lower side acts towards the upper side. At this time, in the aforementioned bearing unit 10, the protruding piece 52 of the bearing shell retainer 50 is positioned... Figure 2 The upper side is arranged so that the surface bears the radial load, thereby restricting the radial movement of shaft 2A (the tilting of shaft 2A).

[0072] Furthermore, when the motor 1 drives the driven component, the force in the rotational direction of the worm gear 3B is converted into a force in the thrust direction and acts on the shaft 2A. The thrust damper 20 of the bearing unit 10 and the bearing connector 30 restrict the shaft 2A from moving in the thrust direction (axial direction) by the force in this thrust direction.

[0073] Figure 8This diagram illustrates a state where the shaft 2A is displaced axially to one side during the drive of motor 1, and a thrust is applied to press into the bearing assembly 30. (See diagram below.) Figure 8 As shown, when the bearing unit 10 is subjected to the aforementioned thrust, the thrust damper 20 shrinks axially to absorb the thrust, and the maximum amount of displacement in the thrust direction of the shaft 2A is limited by the damper side press-in portion 31 of the bearing connector 30 abutting against the end wall 4a of the receiving portion 4.

[0074] It should be noted that at this time, the guide portion 34 of the bearing housing 30 will not detach from the protruding piece 52 of the bearing shell retainer 50, but will instead remain in the space radially inward of the protruding piece 52. Therefore, the radial positions of the bearing shell retainer 50 and the bearing housing 30 will not shift, maintaining a coaxial state. It should also be noted that the gap between the thrust damper 20 and the inner peripheral wall 4b is set to allow the thrust damper 20 to expand and deform radially outward at this time (without hindering the deformation of the thrust damper 20).

[0075] When the worm gear 3B rotates from Figure 8 When the state is reversed, a thrust is applied to shaft 2A in the opposite axial direction. At this time, the thrust damper 20 is stretched in a manner that balances the restoring force of the thrust damper 20 with the resistance of shaft 2A. Thus, the bearing unit 10 becomes, for example, Figure 2 The thrust damper 20 absorbs the noise (reverse noise) generated when the worm gear 3B reverses.

[0076] [3. Effect]

[0077] (1) In the bearing unit 10 and the motor 1 using the bearing unit 10 described above, before the bearing unit 10 is assembled into the gearbox 4, each component 20, 30, 40, and 50 is integrated as a single bearing assembly. As a result, the multiple components 20, 30, 40, and 50 attached to the end 2a of the shaft 2A can be arranged in appropriate positions together, thus simplifying the assembly process and making the assembly operation easier.

[0078] (2) In the bearing unit 10 described above, during assembly to the gearbox 4, only the press-in end 51 of the bearing shell retainer 50 is pressed into the gearbox 4 for assembly, thus allowing the bearing unit 10 to be easily assembled to the gearbox 4. Furthermore, after assembly to the gearbox 4, the bearing connector 30 is released from its lightly pressed-in state with the bearing shell retainer 50. However, even after release, the guide portion 34 of the bearing connector 30 does not completely separate from the protruding piece 52 of the bearing shell retainer 50, and is held to slide freely axially relative to the protruding piece 52. Therefore, the coaxial state of the bearing connector 30 and the bearing shell retainer 50 can be maintained.

[0079] (3) The axial length of the retaining piece 53 of the bearing retainer 50 is shorter than that of the protruding piece 52, and its radial thickness is smaller than that of the protruding piece 52. Therefore, when the oil-impregnated bearing 40 is engaged, it can be held with appropriate force. Furthermore, by setting the radial thickness of the protruding piece 52 to be greater than the radial thickness of the retaining piece 53, the retainer-side pressing portion 33 can be pressed into the radially inner side of the protruding piece 52, and the guide portion 34 can be held with sufficient strength to slide axially. That is, by making the axial lengths of the protruding piece 52 and the retaining piece 53 different, portions extending in the same direction (one axial direction) can be used for different purposes.

[0080] (4) By pressing the bearing retainer 50 into place with the positioning surface 51f of the press-in end 51 of the bearing retainer 50 matching the predetermined position (flat portion) of the receiving portion 4A, the protruding piece 52 of the bearing retainer 50 can be positioned to bear the radial load acting on the shaft 2A. That is, the circumferential position of the bearing retainer 50 can be determined by the positioning surface 51f of the bearing retainer 50 in a manner that positions the protruding piece 52 in the desired position. With this positional relationship, the protruding piece 52, which is thicker than the retaining piece 53, can reliably bear the radial load acting on the shaft 2A, and warping of the shaft 2A can be prevented.

[0081] Furthermore, in this embodiment, the flat portion of the press-in wall 4c, which faces the positioning surface 51, is provided on the worm gear 3B side. In the receiving portion 4A, as... Figure 2 As shown, the worm gear 3B side, which is on the other side of the axial direction, is also part of the curved worm gear receiving space S2. Therefore, by using the portion of the worm gear 3B side pressed into the wall 4c as a flat part for positioning, the complexity of the mold for the gearbox 4 can be suppressed.

[0082] (5) The bearing retainer 50 is provided with a plurality of (e.g., three) protruding pieces 52 and a plurality of (e.g., three, preferably the same number as the protruding pieces 52) retaining pieces 53, and the protruding pieces 52 and retaining pieces 53 are alternately arranged circumferentially to form an inner circumferential surface surrounding the oil-impregnated bearing 40. Thus, the protruding pieces 52 and retaining pieces 53 do not become too small, and the oil-impregnated bearing 40 is held in a well-balanced manner. Furthermore, the size of the protruding pieces 52 used to form a lightly pressed-in state (and subsequently a sliding state) is ensured, and the arrangement of the protruding pieces 52 is also well-balanced.

[0083] (6) A shaft guide surface 51b is provided at the press-in end 51 of the bearing retainer 50, so that when the shaft 2A is inserted into the gearbox 4, the shaft 2A can be easily guided to the inner hole 51h of the bearing retainer 50. Therefore, the assembly operation of the shaft 2A can be performed more easily.

[0084] (7) The base portion of the inner peripheral surface 52f of the protruding piece 52 of the bearing retainer 50 is curved along the outer peripheral surface of the oil-impregnated bearing 40, thus the oil-impregnated bearing 40 can also be retained at the base portion of the protruding piece 52. Furthermore, the base portion of the inner peripheral surface 53f of the retaining piece 53 of the bearing retainer 50... Figure 2 The cross-section shown is flat, which allows the retaining piece 53 to be easily flexed. This further enhances the locking effect, enabling the oil-impregnated bearing shell 40 to be held with more appropriate force.

[0085] (8) In addition, a recess 35 is formed on the bearing contact part 30, so that the grease applied to the contact surface 30f can be left inside the recess 35, which can improve the lubrication performance when the shaft 2A rotates.

[0086] [4. Other]

[0087] The structure of the bearing unit 10 and motor 1 described in the above embodiments is an example and is not limited to the above structure. For example, the recess 35 of the bearing receiving part 30 can be omitted. Conversely, the depth of the recess 35 can be increased so that the axial position of the receiving surface 30f is located at the step position of the cage-side pressing part 33 and the guide part 34, and at the position overlapping with the cage-side pressing part 33.

[0088] Alternatively, a structure replacing the guide portion 34 can be provided on the gearbox 4 side. For example, a structure restricting the radial position of the thrust damper 20 and the bearing connector 30 after the bearing unit 10 is assembled into the gearbox 4 can be provided on the inner peripheral wall 4b. Furthermore, a structure restricting the rotation of the bearing connector 30 can be provided in the receiving portion 4A of the gearbox 4. For example, the portion of the outer peripheral surface of the flange portion 32 of the bearing connector 30 that is cut off by a line segment can be used as a positioning surface, and a planar wall surface can be provided on the inner peripheral wall 4b opposite to this portion. By restricting the rotation of the bearing connector 30, noise generated by the rotation of the bearing connector 30 can be suppressed.

[0089] Furthermore, the shapes of the base portions of the inner circumferential surfaces 52f and 53f in the aforementioned protruding piece 52 and retaining piece 53 are examples and are not limited to the shapes described above. For example, the base portion of the inner circumferential surface 53f of the retaining piece 53 may be curved, and the base portion of the inner circumferential surface 52f of the protruding piece 52 may be flat. The axial length and radial thickness of the protruding piece 52 and retaining piece 53 are also not limited to the above-described cases, and their number is not limited to three each. Additionally, the shaft guide surface 51b and positioning surface 51f of the press-in end 51 of the bearing retainer 50 may be omitted.

[0090] The shapes of the inner bore 20h of the thrust damper 20 and the damper-side pressing portion 31 of the bearing connector 30 are not limited to the above-described forms, as long as they can maintain a mutually pressing state. For example, the shapes of the inner bore 20h of the thrust damper 20 and the damper-side pressing portion 31 of the bearing connector 30 can both be elliptical or rounded quadrilateral. Furthermore, the holding of the bearing connector 30 by the thrust damper 20 is not limited to pressing. For example, the bearing connector 30 can also be held in place by the interlocking of the claw portions provided on the thrust damper 20 and the bearing connector 30.

[0091] Similarly, the shape of the front end of the protruding piece 52 of the bearing retainer 50 and the shape of the retainer-side press-in portion 33 of the bearing connector 30 are not limited to the shapes described above, as long as they can maintain a slightly pressed-in state and can be separated. Similarly, the bearing retainer 50's retention of the bearing connector 30 is not limited to a press-in shape, as long as the bearing retainer 50 can retain the bearing connector 30 in a separable manner.

[0092] The bearing unit 10 can also be applied to shafts other than shaft 2A housed in the gearbox 4. Furthermore, the structure of the motor 1 with the reducer is not limited to the structure described above. The motor 1 with the reducer can also be applied to systems other than the vehicle's power window system.

[0093] Explanation of reference numerals in the attached figures:

[0094] 1... Motor (motor with reducer);

[0095] 2...Motor section;

[0096] 2A... axis;

[0097] 2a...end;

[0098] 3...reduction mechanism;

[0099] 3A...worm gear;

[0100] 3B...worm gear;

[0101] 4... Gearbox;

[0102] 4A... Containment Department;

[0103] 10...bearing unit;

[0104] 20...thrust damper;

[0105] 20h...inner hole;

[0106] 22...the other end face (the other end face);

[0107] 30...bearing connection parts;

[0108] 31...Damper side press-in section;

[0109] 32...Flange portion;

[0110] 33...Cage side press-in part;

[0111] 33f... cylindrical surface;

[0112] 34...Guiding section;

[0113] 34f... cylindrical surface;

[0114] 35... concave part (shaft contact part);

[0115] 40... Oil-impregnated bearings;

[0116] 50... Bearing cage;

[0117] 51... Press-in end;

[0118] 51a...inner circumferential surface;

[0119] 51b...axis guiding surface;

[0120] 51c...outer peripheral surface;

[0121] 51f... Positioning surface;

[0122] 52...protruding piece;

[0123] 52f...Inner circumferential surface (inner surface facing the oil-bearing bearing side);

[0124] 53...holding tablets;

[0125] 53f...Inner circumferential surface (inner surface facing the oil-bearing bearing side);

[0126] S1... Worm gear housing space;

[0127] S2...worm gear housing space;

[0128] S3... Bearing housing space.

Claims

1. A bearing unit, characterized in that, The bearing unit includes: A thrust damper that is axially extendable and retractable along a shaft disposed within a gearbox, and whose movement toward one side of said axial direction is restricted. A bearing assembly is held in the thrust damper from the opposite side of the axial direction of the thrust damper; A bearing retainer that holds the bearing assembly in a manner that allows it to be axially separable from the bearing assembly; and An oil-impregnated bearing shell, held in the bearing shell cage, and disposed on the other side of the bearing coupling. Prior to assembly into the gearbox, the thrust damper, the bearing assembly, the bearing cage, and the oil-impregnated bearing are integrated into one unit. The bearing cage has a press-in end that is press-fitted into and fixed to the receiving portion of the gearbox. Before being assembled into the gearbox, the bearing assembly is lightly pressed into the bearing retainer. After being assembled into the gearbox, it is pressed against one side of the axial direction to release the lightly pressed-in state from the bearing retainer and is held to slide freely relative to the bearing retainer in the axial direction.

2. The bearing unit according to claim 1, characterized in that, The bearing assembly includes: a damper-side press-in portion that presses into the inner bore of the cylindrical thrust damper; a flange portion that abuts against the other end face of the thrust damper; and a cage-side press-in portion that extends from the flange portion toward the other end and has a cylindrical surface. The bearing retainer has a protruding tab that extends from the press-in end toward one side and is lightly pressed in by the cylindrical surface of the retainer side press-in portion; And a retaining plate, which extends from the press-in end toward one side and retains the oil-impregnated bearing. The oil-impregnated bearing is disposed on one of the press-in ends of the bearing cage.

3. The bearing unit according to claim 2, characterized in that, The bearing assembly has a guide portion that extends from the cage-side press-in portion to the other side and has a cylindrical surface with a diameter smaller than that of the cage-side press-in portion. After being assembled into the gearbox, the bearing assembly is pressed against one side of the axial direction to release it from the lightly pressed-in state with respect to the bearing retainer, and is held so that the guide portion can slide freely in the axial direction relative to the protrusion of the bearing retainer.

4. The bearing unit according to claim 2 or 3, characterized in that, The axial length of the retaining piece of the bearing retainer is shorter than that of the protruding piece of the bearing retainer, and the radial thickness is smaller than that of the protruding piece of the bearing retainer.

5. The bearing unit according to claim 4, characterized in that, The press-in end of the bearing cage has a positioning surface that is planar on a portion of its outer circumferential surface. The bearing retainer is configured such that, when pressed in and fixed in a state that aligns the positioning surface with a predetermined position of the receiving portion, the protruding piece is positioned to bear the radial load acting on the shaft.

6. The bearing unit according to claim 2 or 3, characterized in that, The bearing cage has a plurality of the protruding tabs and a plurality of the retaining tabs. The protruding pieces and the retaining pieces are alternately arranged circumferentially to form the inner circumferential surface surrounding the oil-impregnated bearing.

7. The bearing unit according to claim 1 or 2, characterized in that, The press-in end of the bearing retainer is annular and has a shaft guide surface whose inner diameter gradually decreases from the end face on the other side toward the one side.

8. The bearing unit according to claim 2 or 3, characterized in that, In the cross-section of the bearing cage cut along the axial direction, The portion of the protruding piece on the inner surface facing the oil-impregnated bearing bush, at the pressed-in end, is curved along the outer circumferential surface of the oil-impregnated bearing bush. The portion of the retaining piece on the press-in end side of the inner surface facing the oil-impregnated bearing extends axially instead of along the outer peripheral surface of the oil-impregnated bearing.

9. The bearing unit according to claim 1 or 2, characterized in that, A shaft abutment portion is formed on the end face of the other side of the bearing connector, which abuts against the shaft and has a shape capable of accumulating grease.

10. A motor with a speed reducer, characterized in that, The motor with a speed reducer includes: The motor section includes a shaft; A reduction mechanism comprising a worm gear that rotates integrally with the shaft of the motor unit, and a worm wheel meshing with the worm gear; and A gearbox, which mounts the motor unit and houses the reduction gear mechanism. The shaft disposed within the gearbox is provided with a bearing unit according to any one of claims 1 to 9 at its end.

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