JPH053638U - Oil-impregnated bearing - Google Patents

Abstract

(57) [Abstract] [Purpose] In an oil-impregnated bearing for a rotating shaft subjected to an unbalanced load, a non-porous portion arranged on a bearing surface that is unevenly contacted can be easily positioned. [Structure] The load acting direction of the rotary shaft is calculated from the design condition of the drive or transmission means for applying an unbalanced load to the rotary shaft, and the bearing surface of the oil-impregnated bearing facing the calculated load acting direction of the rotary shaft is non-porous. Position and position the parts. For example,
When the oil-impregnated bearing supports the rotating shaft that receives an eccentric load from the worm reducer, the worm gear tooth normal pressure α
From the n, the lead angle λ ₀ , and the friction coefficient μg between the worm gear and the worm wheel, the offset load acting direction θ of the rotary shaft is calculated by the following formula. θ = tan ^-1 [(cosαn sinλ ₀ + μg cosλ ₀ ) / sinαn
]

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention relates to an oil-impregnated bearing (OILES metal) having a non-porous portion, In small motors for automobiles where oil is difficult, especially the contact position between the rotating shaft and the bearing It is suitable for use in motors where the device is biased in a specific direction. This makes it easy to set the position of the non-porous portion arranged at a fixed contact position.

[0002]

[Prior art]

  Conventionally, small motors for automobiles such as wiper motors have a worm gear on the motor output shaft. The ears are integrally formed or connected to each other and mesh with the worm wheel to transmit the rotational force. , The load direction of the motor output shaft or worm gear shaft is specified as a unit. Is used in a state in which the contact position between these shafts and bearings is biased in a specific direction. It When a high output is required in such a motor, the bearing load becomes high. Therefore, a ball bearing having a high bearing load is generally used.

[0003]   However, ball bearings have problems in terms of cost, noise, etc. It is unavoidable that we often use sliding bearings made up of oil-impregnated bearings, but they rotate unevenly. The contact surface against which the shaft is pressed is significantly worn, has a short life, and has a problem in terms of durability. .

[0004]   As a measure against the above wear, wrap a segment-shaped bearing member with high porosity By arranging bearing members with low porosity in this way, wear is reduced and life is reduced. Has been proposed (see Japanese Examined Patent Publication No. 35-13253). However, The proposed bearing has a complicated shape, is costly, and is not practical. Have.

[0005]   As a solution to the above-mentioned conventional drawbacks, the present applicant has previously filed Japanese Patent Application No. 2-173. No. 816 oil-impregnated bearing in which a non-porous portion is arranged on a specific sliding contact surface with uneven contact with the shaft I am proposing With oil-impregnated bearings equipped with this non-porous part, when the shaft is rotating, In the area where the non-porous portion is arranged, the lubricating oil is hermetically held between the shaft and the bearing, and the high pressure is maintained. Bearing, it can withstand high bearing loads, thus reducing wear and providing good lubrication. Has the advantage that

[0006]

[Problems to be solved by the device]

  Although the oil-impregnated bearing provided with the non-porous portion according to the applicant's application has the above advantages, When arranging the porous part on the rotating shaft and mounting the bearing, In practice, it is difficult to position the touching part so that it touches the porous part. Is the subject.   That is, since the shaft is rotating, the contact point between the bearing and the rotating shaft is not constant, It is difficult to determine the non-porous arrangement position from the contact.

[0007]   The present invention has been made in view of the above problems, and the installation position of the non-porous portion is extremely Therefore, it is not necessary to accurately determine the position where an eccentric load is applied during use. The purpose is to arrange a porous portion to improve the above-mentioned lubrication performance and the like.

[0008]   That is, the present invention relates to an oil-impregnated bearing that supports a rotating shaft that receives an unbalanced load. Calculate the load direction of the rotating shaft from the design conditions of the drive or transmission means that apply an unbalanced load to the Then, the non-porous portion is formed on the bearing surface of the oil-impregnated bearing facing the determined load direction of the rotating shaft. The invention provides an oil-impregnated bearing characterized by locating and arranging.

[0009]   That is, the action direction of the unbalanced load on the rotating shaft is determined by the usage conditions such as the rotating speed of the rotating shaft and the load condition. Rotation without being affected by conditions and bearing conditions such as bearing installation position Design rules for transmission means or drive means that rotate integrally with the shaft and apply an unbalanced load to the rotating shaft It is calculated from the rated conditions that consist of cases. Further, preferably, a lubricating strip I'm trying to add more cases.

Specifically, when the oil-impregnated bearing supports a shaft that rotates integrally with a worm gear that meshes with a worm wheel, the tooth orthogonal pressure αn of the worm gear, the lead angle λ ₀ , and the friction coefficient between the worm gear and the worm wheel. The load direction θ of the worm shaft is calculated from μg by the following formula. θ = tan ^-1 [(cosαn sinλ ₀ + μg cosλ ₀ ) / sinαn]

[0011]

[Action]

  According to the present invention, as described above, the transmission means or the driving means for imparting an eccentric load to the rotating shaft is used. Since the action direction of the eccentric load is calculated from the stage design conditions, the non-porous part can be accurately It can be positioned on the bearing surface that receives the load. Therefore, install a non-porous part It is possible to surely improve the lubrication performance due to

[0012]

【Example】

  Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.   FIG. 1 shows an oil-impregnated bearing 1 according to the present invention as a motor output shaft of a wiper motor 2 of an automobile. 3 shows an embodiment installed to support the No. 3 bearing.   The motor output shaft 3 is formed integrally with the shaft of the worm gear 4, and Since the home gear 4 meshes with the worm wheel 5, the worm wheel 5 The load is pressed in the direction of arrow Z, so that the oil-impregnated bearing 1 slides in the lower part of the figure. Unbalanced load is applied to the contact surface.

[0013]   As shown in FIG. 2, the oil-impregnated bearing 1 is an inner diameter aligned type, and is in sliding contact with an unbalanced load. Except for the surface, the porous portion 6 is made of a sintered material such as Cu-based material. Lubricating oil is permeated and retained in the hole 6 to form an oil-impregnated bearing.   A non-porous portion 7 is provided on the sliding contact surface. This non-porous portion 7 is usually The porous material is crushed using a pressing tool when sizing one of the bearing processing steps. In this way, the porous material is molded to a required thickness from the surface. The above non-porous portion 7 is a white metal or the like as disclosed in the above-mentioned prior application of the applicant. And then place this non-porous part in the molding die when manufacturing the bearing Alternatively, a powder of a sintered material for use may be poured and molded.

[0014]   The feature of the present invention resides in that the arrangement position of the non-porous portion 7 is specified. Positioning of the porous portion 6 will be described with reference to FIG. 3 which is a schematic view of FIG.   In FIG. 3, 1A and 1B are motor output shafts integrated with the worm gear shaft, that is, rotations. It is a bearing that supports both sides of the rolling shaft 3 (only the axis is shown). The maca 10 is fixed. As described above, the worm gear is attached to the tip of the rotary shaft 3. 4 is fixed, and the worm gear 4 is meshed with the worm wheel 5.

[0015]   When the rotary shaft 3 rotates to the right as shown by the arrow X in the figure, the worm wheel The worm gear 4 receives the reaction force of Pt and Pg by the roll 5. At this time, bearing 1A Receives the force of Ft and Fg from the above Pt and Pg, and as a result, the total force becomes Fx. Yo Therefore, as shown in FIG. 4, the acting direction of the load that the bearing A1 receives from the rotating shaft 3 is Fg. From the angle θ to the right.

[0016]   The angle θ can be calculated by the following equations that give each dimension.   That is, the distance between the bearings 1A and 1B ... Lo,         Distance between bearing 1B and worm gear 4 ... L₁         Rotational force of rotating shaft 3 ... T         Worm gear 4 pitch radius ・ ・ ・ r         Orthogonal pressure of worm gear 4 ・ ・ ・ αn         Lead angle of worm gear 4 ... λ₀         Friction coefficient between worm gear 4 and worm wheel 5 μg         Reaction force in the normal direction applied in the direction perpendicular to the teeth of the worm gear 4 ... Pn Then,   Ft = Pt × L₀/ L₁= T / r × L₀/ L₁                        (1 set   Fg = Pg × L₀/ L₁                                         Equation (2)   Pg = Pn sin αn Equation (3)   Pn = Pt / (cosαn sinλ₀＋ μg cos λ₀) Equation (4)   Substituting equation (4) into equation (3) above,   Pg = Pt sinαn / (cosαn sinλ₀＋ μg cos λ₀) Equation (5) Is obtained. Substituting equation (5) into equation (2),   Fg = Pt sin α × (L₀/ L₁) / (Cosαn sinλ₀＋ μg cos λ₀) Equation (6) Is obtained.   Furthermore, the angle θ of the load acting direction is   tan θ = Ft / Fg Equation (7) Because   θ = tan^-1(Fr / Fg) Equation (8) Can be calculated by Substituting equations (1) and (6) into equation (8) above and rearranging,   θ = tan^-1((Cos α n sin λ₀＋ μg cos λ₀/ Sinαn)] Equation (9) Is obtained.

[0017]   As described above, the tooth orthogonal pressure αn, the lead angle λo, and the lead angle λo, which are the design conditions of the worm gear 4, are set. And the friction coefficient μg between the worm gear 4 and the worm wheel 5 is given, The heavy action direction θ can be calculated. That is, worm gear 4 and worm wheel It can be uniquely obtained by calculating it from the design condition with the rule 5. In other words, times Without being affected by the usage conditions of the rolling shaft 3, for example, the rotation speed and the magnitude of the load, In addition, the bearing position such as the distance between the bearings 1A and 1B and the distance between the bearings and the worm gear. It is not affected by the location.

[0018]   From the design conditions of the worm gear 4 and worm wheel 5 as described above, After determining the application direction θ, the sliding contact surface of the bearing at the position opposite to this acting direction θ The central position of the porous portion 7 is arranged.

[0019]   For example, if we put an example of concrete dimensions in the above equation (9) and calculate, θ = 32 ° is obtained. Was given. Based on this angle, as shown in FIG. 5, since it is clockwise, the above 32 ° The non-porous portion 7 is arranged on the sliding contact surface of the bearing 1A in the required region in the right rotation direction from the vicinity of I put it.

[0020]   The bearing 1 having the above structure was used in the apparatus shown in FIG. 1 and the friction coefficient at this time was measured. The result is shown in Fig. 6, and the friction coefficient is the lowest at 30 ° as shown. It was confirmed that θ calculated by equation (9) can be used as the predicted position. It was

[0021]   As described above, the bearing 1 in which the non-porous portion 7 is arranged on the sliding contact surface in the load acting direction Is used, the operational characteristics disclosed in the above-mentioned prior application can be obtained.   That is, when the rotating shaft 3 is pressed against the non-porous portion 7 by the load and slides, the non-porous portion 7 7, the temperature of the porous portion 6 around the non-porous portion 7 rises. . This heating causes the lubricating oil that has permeated the inside of the porous portion 6 to ooze out and It flows into the sliding contact surface of the quality part 7 by the pump action. Wetting of the surface of this non-porous portion 7 The lubricating oil is retained between the shaft and the rotating shaft 3, becomes high pressure, and bears the bearing load. Now, ideal fluid lubrication can be realized.

[0022]   In the description of FIGS. 3 and 4, when the rotary shaft 3 rotates to the right. However, even when the rotating shaft 3 rotates to the left, It goes without saying that the load acting direction can be obtained from the design conditions of the home wheel. not.   Further, the means for applying the load to the rotating shaft 3 in a biased manner is limited to the worm speed reducer. However, various driving means or transmission means are included. These drive means If the transmission means applies an eccentric load to the rotary shaft, The load acting direction can be obtained from the design conditions of the transmission means, and it corresponds to the obtained load direction. The non-porous portion is arranged on the sliding contact surface of the bearing.

[0023]

[Effect of device]

  As is clear from the above description, in the present invention, the sliding contact in which the rotating shaft is biased in pressure contact In oil-impregnated bearings in which the non-porous portion is arranged on the contact surface, the position of the non-porous portion Device, such as a worm reducer that applies a load to the rotating shaft, Since it is calculated and set only from the measurement conditions, the installation position of the non-porous part can be accurately and accurately set. It can be easily positioned.

[0024]   Further, as described above, the non-porous portion can be accurately arranged at the position where the rotating shaft is in pressure contact. And by arranging the non-porous part, it is possible to improve lubrication performance and durability. It has the advantage that

[Brief description of drawings]

FIG. 1 is a sectional view of a motor with a worm reducer using the bearing of the present invention.

FIG. 2 is an enlarged sectional view of the bearing shown in FIG.

FIG. 3 is a schematic diagram for explaining a calculation method for obtaining an installation position of a non-porous surface according to the present invention.

FIG. 4 is a schematic view showing an action direction of a load acting on the bearing in FIG.

FIG. 5 is an explanatory diagram showing the arrangement position of the non-porous portion calculated in FIG.

FIG. 6 is a diagram showing an experimental result of measuring a wear coefficient of a bearing according to the present invention.

[Explanation of symbols]

1 (1A, 1B) oil-impregnated bearing 3 rotation axes 4 Worm gear 5 warm wheels 6 Porous part 7 Non-porous part

Claims (2)

[Scope of utility model registration request] 1. An oil-impregnated bearing that supports a rotating shaft that receives an unbalanced load, wherein the load acting direction of the rotating shaft is calculated from the design condition of the drive or transmission means that applies the unbalanced load to the rotating shaft, and the obtained rotation is obtained. An oil-impregnated bearing characterized in that the center position of the non-porous portion is positioned and arranged on the bearing surface of the oil-impregnated bearing facing the load acting direction of the shaft. Wherein said oil-impregnated bearing is intended for supporting the shaft of the worm gear, the tooth perpendicular pressure αn of the worm gear, lead angle lambda _0, than the friction coefficient μg of the worm gear and the worm wheel, the polarization of the rotating shaft by the following formula The oil-impregnated bearing according to claim 1, wherein a load acting direction θ is calculated. θ = tan ^-1 [(cosαn sinλ ₀ + μg cosλ ₀ ) / sinαn
]