JP2022052709A - Slide bearing device for water pump - Google Patents

Abstract

To provide a slide bearing device for a water pump which imparts a high dynamic pressure effect to a lubrication groove formed at the slide bearing or an end face of a thrust receiver, and is reduced in a friction coefficient between the slide bearing and the thrust receiver.SOLUTION: A slide bearing device is composed of a slide bearing 8 and a thrust receiver, and the slide bearing 8 comprises a land part 13 being a slide face, and a lubrication groove 14 for discharging lubrication water to an outside diameter side from an inside diameter side at a bearing end face. The lubrication groove 14 has an inclination face which is inclined to the land part 13, and in a projection figure when viewing the end face having the lubrication groove 14 from a front side, the lubrication groove 14 is formed of a region which is surrounded by a line component A and a line component B which are connected to the outside diameter side from the inside diameter side of the end face, a circular arc C progressing along an inside diameter face, and a circular arc D progressing along an outside diameter face. A length of the circular arc C is equal to or longer than a length of the circular arc D.SELECTED DRAWING: Figure 2

Description

The present invention relates to a slide bearing device for a water pump used for circulation of cooling water such as an automobile engine, an inverter, a battery, or a fuel cell, and circulation of hot water such as a water heater and a floor heating device.

Water pumps are used to circulate cooling water for automobile engines, inverters, batteries, or fuel cells, and to circulate hot water for water heaters and floor heating equipment. Conventionally, as a typical example of a water pump used for such an application, a magnet pump as described in Patent Document 1 or a DC brushless pump as described in Patent Document 2 is known. A conventional water pump will be described with reference to FIG. FIG. 12 is a cross-sectional view of the DC brushless pump. In the pump 21, the motor 32 has a winding 22 in which a coil is arranged to generate a magnetic field, and the control unit controls the generation of the magnetic field. In order to follow the generated magnetic field, the impeller 24 to which the permanent magnet 23 is fixed is rotatably supported by the shaft 25. Circulating water is absorbed and drained by the impeller 24 rotating following the rotating magnetic field. The shaft 25 is fixed to the casing 26 and is supported by the shaft support 27a of the cover 27. The impeller 24 is rotatably supported with respect to the shaft 25 via the slide bearing 28, and the shaft 25 and the slide bearing 28 rotate and slide. Further, both end faces of the slide bearing 28 are rotationally slid in the thrust direction with the thrust plates 29 and 30 provided between the shaft support 27a of the cover 27 and the casing 26, respectively. A slight gap is provided between both end faces of the slide bearing 28 and the thrust plates 29 and 30, respectively.

Along with the rotating magnetic field generated from the winding 22, the impeller 24 rotates following the attraction and repulsion of the fixed permanent magnet 23. As a result, a pumping action is generated, the circulating water is sucked in from the direction of arrow X, and the circulating water is discharged in the direction of arrow Y. The impeller 24 is pressed against the cover 27 by the differential pressure at this time, and the end face of the slide bearing 28 and the thrust plate 29 rotate and slide. There is almost no sliding between the slide bearing 28 and the thrust plate 30 on the casing 26 side, and it is limited to a moment when starting and stopping, or during abnormal operation such as idle operation in which the pump is operated without circulating water. Therefore, the thrust plate 30 may not be used on the casing 26 side, and the casing 26 may be directly slid with the slide bearing 28.

In a water pump as described above, the coefficient of friction can be reduced by providing a lubrication groove in either the slide bearing or the thrust receiver. Here, Patent Document 3 has a sliding surface orthogonal to the rotating shaft, and has a collar fixed to the rotating shaft and a thrust bearing fixed to the fixing member and relatively rotating along the sliding surface. The thrust support device provided is disclosed. This thrust bearing has a land portion parallel to the sliding surface of the collar, a tapered portion that inclines with respect to the sliding surface and generates dynamic pressure in the lubricating liquid between the collar and the collar due to relative rotation, and a groove. It is provided. The coefficient of friction is reduced by generating dynamic pressure with the tapered portion.

Further, the present inventor selects from a suction means for sucking circulating water from one end surface side of the slide bearing to the bearing inner diameter surface side and a discharge means for discharging the circulating water from the bearing inner diameter surface side of the slide bearing to the other end surface side. A water pump having at least one bearing has been proposed (Patent Document 4). In this water pump, friction is reduced by improving the supply (discharge capacity) of circulating water to the sliding surface.

Japanese Patent No. 3099434 Japanese Unexamined Patent Publication No. 2006-200427 Japanese Patent No. 5761560 Japanese Unexamined Patent Publication No. 2015-183650

In recent years, water pumps are required to reduce the coefficient of friction for energy saving and the vibration reduction for improving quietness. The thrust bearing of Patent Document 3 is provided with a tapered portion that generates a dynamic pressure in the lubricating liquid between the collar and the collar due to relative rotation, but the angle and length of the tapered portion have not been studied. Further, in the thrust bearing exemplified in Patent Document 3, the boundary between the tapered portion and the land portion is formed along the radial direction of the thrust bearing, and it is considered that there is room for further improvement in the dynamic pressure effect. ..

The present invention has been made to deal with such a problem, and is a waterer which imparts a high dynamic pressure effect to a lubrication groove provided on an end face of a slide bearing or a thrust receiver and reduces a friction coefficient between the two. It is an object of the present invention to provide a slide bearing device for a pump.

The slide bearing device for a water pump of the present invention has a cylindrical shape fixed to an impeller, a shaft for supporting the impeller, and the impeller for rotatably supporting the impeller with respect to the shaft. A sliding bearing, a thrust receiver that slides on each end surface of the sliding bearing, and a casing and a cover that accommodate the impeller and form a pump chamber are provided, and the impeller rotates through the pump chamber. A water pump sliding bearing device used for a water pump that sucks and discharges circulating water, wherein the water pump sliding bearing device comprises the sliding bearing and the thrust receiver, and has at least one end surface of the sliding bearing or the above. A land portion serving as a sliding surface and a lubricating groove for discharging the circulating water from the inner diameter side to the outer diameter side are provided on the end surface of at least one member of the thrust receiver, and the lubrication groove is the land portion. In the projection view when the end surface having the inclined surface inclined with respect to the above and the end surface provided with the lubrication groove is viewed from the front (axial direction), the lubrication groove is connected from the inner diameter side to the outer diameter side of the end surface. It consists of a region surrounded by the line A and the line B, the arc C along the inner diameter surface, and the arc D along the outer diameter surface, and is the length of the arc C equal to the length of the arc D? , Or long.

In the present invention, the "thrust receiver" includes not only a dedicated thrust plate provided for receiving the thrust load of the slide bearing but also the other member when the thrust load is received by another member such as a casing. The dedicated thrust plate may be, for example, an annular shape. Further, "circulating water" includes not only water but also antifreeze solution, chemical solution and the like.

The angle formed by the line segment A and the line segment B is 0 ° to 15 °.

The line segment A is located on the upstream side in the relative rotation direction with respect to the line segment B, and in the lubricating groove, the cross-sectional shape of any cut surface orthogonal to the line segment A is the inclined surface. It is a substantially right-angled triangle having an oblique side, and is characterized in that the angle of the internal angle with the intersection of the line segment A and the cut surface as the apex is 3 ° to 30 °. Here, the "relative rotation direction" refers to the rotation direction of itself when one of the members of the slide bearing and the thrust receiver rotates, and when it rotates, and when the mating material rotates, it means the rotation direction of itself. The direction opposite to the rotation direction of the mating material.

The maximum depth of the lubricating groove is 0.1 mm to 1.0 mm.

A plurality of the lubricating grooves are arranged on the end face at intervals in the circumferential direction.

The member in which the lubrication groove is formed has an axial center on an extension line of the line segment A, and the plurality of lubrication grooves are downstream of the center line passing through the line segment A of the member in the relative rotation direction. It is characterized in that it is provided at a position offset to the side.

The slide bearing is an injection-molded body of a resin composition, has the lubrication groove on at least one end surface thereof, and has a gate mark formed on the outer diameter surface of the slide bearing. It is characterized in that a weld portion is formed in the lubrication groove and the weld portion is not formed in the land portion.

The thrust receiver is characterized in that the directions of the streaks formed by machining the surface sliding with the slide bearing are not concentric circles.

It is characterized in that the direction of the streaks is random.

In the slide bearing device of the present invention, a land portion serving as a sliding surface and a lubricating groove for discharging circulating water are provided on the end surface of at least one member of the sliding bearing or the thrust receiver, and the lubricating groove is a land. Since the lubrication groove has a predetermined structure and has an inclined surface inclined with respect to the portion, excellent low friction characteristics can be realized. Excellent low friction characteristics are obtained because the lubrication groove provided on the end face of the slide bearing or thrust receiver can exert an excellent dynamic pressure effect due to the groove shape, and the lubrication groove is formed from the inner diameter side to the outer diameter side. This is because the circulating water is easily supplied to the sliding surface between the slide bearing and the thrust receiver by the communication, and the lubrication state is improved. That is, the lubricating groove alone has both a dynamic pressure effect and an effect of improving the supply of circulating water to the sliding surface. Therefore, compared to the conventional configuration in which a tapered portion for generating dynamic pressure and a lubricating groove are provided as in the case of a thrust bearing, the configuration can be simplified and the cost can be reduced.

In particular, in the present invention, the length of the arc C along the inner diameter surface in the lubrication groove is equal to or longer than the length of the arc D along the outer diameter surface, and the outlet is the inlet in the flow direction of the circulating water. Since it is the same as or narrower than the inlet, it is easier to generate dynamic pressure as compared with a configuration in which the outlet is wider than the inlet as in a conventional thrust bearing.

Further, the slide bearing is an injection molded body of a resin composition and has a lubrication groove on at least one end surface thereof. In the slide bearing, a weld line is formed in the lubrication groove and a weld line is formed in the land portion. Since it is not, the flatness of the land part can be improved. By improving the flatness, the vibration generated during sliding can be reduced, and excellent quietness can be realized.

It is sectional drawing of the water pump using the slide bearing apparatus of this invention. It is a projection drawing which looked at the end face of the slide bearing in this invention from the front. It is sectional drawing which shows the cross-sectional shape of a lubrication groove. It is sectional drawing which shows the other example of the slide bearing in this invention. It is a figure for showing the change by the wear of a sliding surface. It is a projection drawing which looked at the end face of the test piece of Examples 1 to 4 from the front. It is a projection drawing which looked at the end face of the test piece of Examples 5-11 from the front. It is a projection drawing which looked at the end face of the test piece of the comparative example 1 from the front. It is a projection drawing which looked at the end face of the test piece of the comparative example 2 from the front. It is a time-dependent change of the dynamic friction coefficient of Example 12. It is a time-dependent change of the dynamic friction coefficient of Example 13. It is a cross-sectional view of a conventional water pump.

An example of a water pump using the slide bearing device of the present invention will be described with reference to FIG. As shown in FIG. 1, in the water pump 1, the casing 6 and the cover 7 are fixed to form a pump chamber for accommodating the impeller 4. The casing 6 and the cover 7 are sealed via the packing 11 to prevent the circulating water in the pump chamber from leaking. The motor 12 generates a magnetic field by having the winding 2 in which the coil is arranged, and the control unit controls the generation of the magnetic field. In order to follow the generated magnetic field, the impeller 4 to which the permanent magnet 3 is fixed is rotatably supported by the shaft 5 in the pump chamber. Circulating water is absorbed and drained by the impeller 4 rotating in the pump chamber following the rotating magnetic field. Specifically, with the rotating magnetic field generated from the winding 2, the impeller 4 rotates following the attraction repulsion of the fixed permanent magnet 3, which causes a pumping action to generate circulating water from the direction of arrow X. And spit out circulating water in the direction of the arrow Y.

The shaft 5 is fixed to substantially the center of the casing 6 and is supported by the shaft support 7a of the cover 7. The impeller 4 is rotatably supported with respect to the shaft 5 via a cylindrical slide bearing 8 fixed to the center thereof. The shaft 5 is a fixed shaft (does not rotate), and the outer diameter surface of the shaft 5 and the inner diameter surface of the slide bearing 8 rotate and slide. Both end faces of the slide bearing 8 are rotationally slid in the thrust direction with the thrust plates 9 and 10, which are thrust receivers provided between the shaft support 7a of the cover 7 and the casing 6, respectively. A "sliding bearing" is a component that slides under a load on the inner diameter and the end face, and is not necessarily limited to one component, but may be divided into two or more components, and even if the materials are different. good.

In the present invention, in this water pump, circulating water is discharged from the inner diameter side to the outer diameter side of the slide bearing 8 by the relative rotation between the thrust receiver (thrust plates 9 and 10) and the slide bearing 8 when the impeller 4 is rotating. A lubrication groove is provided. This lubrication groove is formed on an end surface of the slide bearing 8 on the circulating water discharge side and at least one thrust sliding surface selected from the thrust receivers (thrust plates 9, 10) that slide on the end surface.

In the form of FIG. 1, the impeller 4 is pressed against the cover 7 side by the differential pressure during rotation, and one end surface of the slide bearing 8 rotates and slides with the thrust plate 9. There is almost no sliding between the other end surface of the slide bearing 8 and the thrust plate 10 on the casing 6 side. The flow direction of water due to the differential pressure is from the thrust plate 10 side to the thrust plate 9 side. In FIG. 1, a lubrication groove is formed on an end surface of the slide bearing 8 that slides on the thrust plate 9, and FIG. 2 shows a projection drawing of the end surface when viewed from the front.

As shown in the projection drawing (plan view) of FIG. 2, the slide bearing 8 has a lubrication groove that communicates a land portion 13 serving as a sliding surface with an inner diameter surface 8a and an outer diameter surface 8b on an annular bearing end surface. 14 and. In the slide bearing 8, the portion other than the lubrication groove 14 is only the land portion 13, and no other groove or recess is formed on the end surface of the bearing. Further, the arrow Z in FIG. 2 indicates the rotation direction of the slide bearing 8.

As shown in FIG. 2, the lubrication groove 14 is a groove having a groove bottom surface 14a (see FIG. 3) inclined with respect to the land portion 13 and generating dynamic pressure by relative rotation between the slide bearing 8 and the thrust receiver. be. Three lubrication grooves 14 are provided on the end face of the bearing at intervals in the circumferential direction. The plurality of lubrication grooves 14 are preferably provided at equal intervals in the circumferential direction, and in FIG. 2, the angular interval between the adjacent grooves is 120 °. This interval is the interval of the angle formed by the line segments A of each lubrication groove 14. The number of lubrication grooves 14 is not particularly limited. The larger the number of lubrication grooves 14, the greater the dynamic pressure effect, but the surface pressure of the sliding surface between the slide bearing 8 and the thrust receiver increases, so this is set in consideration of usage conditions and the like.

Further, the line segment A of the lubrication groove 14 has an extension line passing through the shaft center O of the slide bearing 8. In this case, the plurality of lubrication grooves 14 are provided at positions offset to the downstream side in the rotational direction from the center line OA passing through the line segment A of the slide bearing 8.

As shown in FIG. 2, each lubrication groove 14 is located on the line segment A connecting from the inner diameter side to the outer diameter side of the bearing end face and on the downstream side in the rotational direction of the sliding bearing 8 from the line segment A, and is located on the bearing end face. It is composed of a region surrounded by a line segment B connecting from the inner diameter side to the outer diameter side, an arc C along the inner diameter surface 8a, and an arc D along the outer diameter surface 8b. The slide bearing 8 of FIG. 2 is characterized in that the length of the arc C is longer than the length of the arc D. When the slide bearing 8 is rotating, the circulating water is discharged from the inner diameter side to the outer diameter side, and the shape of the lubrication groove 14 is narrowed in this flow direction, so that the dynamic pressure effect can be enhanced. Further, the ratio of the length of the arc C to the length of the arc D is preferably 1/3 <(the length of the arc D) / (the length of the arc C) <1. The length of the arc C may be equal to the length of the arc D.

Further, in the lubrication groove 14, it is preferable that the area of the opening on the inner diameter side is equal to or larger than the area of the opening on the outer diameter side. The "area of the opening on the inner diameter side" can be calculated from the arrow view when the inner diameter side is viewed from the center line OA of the slide bearing along the line segment A. Further, the "area of the opening on the outer diameter side" can be calculated from the arrow view when the center line OA is viewed along the line segment A from the outer diameter side.

In FIG. 2, the angle θ1 indicates the angle formed by the line segment A and the line segment B of the lubrication groove 14. More specifically, it refers to an acute angle (0 ° or more and 90 ° or less) among the angles formed by the extension line of the line segment A and the extension line of the line segment B. The larger the angle θ1, the better the dynamic pressure effect, but the higher the surface pressure. Therefore, the angle θ1 is preferably 0 ° to 15 °. In FIG. 2, the line segment A and the line segment B are not parallel, and the angle θ1 is larger than 0 °. In this embodiment, the angle θ1 is preferably 1 ° to 15 °, more preferably 5 ° to 15 °, and even more preferably 10 ° to 15 °.

As shown in Examples described later, the line segment A and the line segment B may be parallel to each other (angle θ1 = 0 °). Also in that case, the length of the arc C is longer than the length of the arc D.

Subsequently, FIG. 3 shows a cross-sectional view taken along the line aa of FIG. FIG. 3 is a cross-sectional view of the lubricating groove cut along a plane orthogonal to the line segment A. As shown in FIG. 3, the cross-sectional shape of the lubrication groove 14 is a right triangle. This right _triangle has vertices at the intersection v1 between the line segment _A and the cut surface, the intersection v2 between the line segment B and the cut surface, and the intersection v3 of the groove _bottom surface 14a and the groove side surface 14b, respectively. Further, the hypotenuse of the right triangle corresponds to the groove bottom surface 14a of the lubrication groove 14. The groove bottom surface 14a is an inclined surface inclined with respect to the land portion 13, and the groove depth becomes shallow toward the upstream side in the rotation direction Z. When the slide bearing 8 rotates, the circulating water supplied into the lubrication groove 14 acts to be pushed toward the intersection _v1 . Therefore, by providing such a lubrication groove 14, dynamic pressure due to circulating water is generated.

The inclination angle θ2 (which is also an internal angle with the intersection _v1 as the apex) with respect to the land portion 13 of the groove bottom surface 14a is preferably 3 ° to 30 °. If the angle θ2 is less than 3 °, the flow rate of the circulating water passing through the lubricating groove may decrease, and the supply of the circulating water to the sliding surface between the slide bearing and the thrust receiver may be insufficient. If the angle θ2 exceeds 30 °, the dynamic pressure effect may be insufficient. Further, the angle θ2 is more preferably 5 ° to 20 °. The angle θ2 may be constant from the inner diameter side to the outer diameter side, or may change continuously. When the angle θ2 changes, each angle θ2 in an arbitrary cross section is preferably in the range of 3 ° to 30 °, and more preferably in the range of 5 ° to 20 °.

In the lubrication groove 14, the maximum depth H of the slide bearing 8 in the axial direction is preferably 0.1 to 1.0 mm. The maximum depth H is the depth from the land portion 13 to the deepest portion of the lubrication groove 14. If the maximum depth H is less than 0.1 mm, the flow rate of circulating water passing through the lubricating groove 14 decreases, and the supply of circulating water to the sliding surface between the land portion 13 of the end face and the thrust receiver is insufficient. There is a risk of becoming. Further, if the maximum depth H exceeds 1.0 mm, the dynamic pressure effect due to the circulating water being pushed toward the intersection _v1 may be insufficient. In FIG. 3, the deepest portion of the lubrication groove 14 is formed linearly from the inner diameter side to the outer diameter side. The groove depth of the lubrication groove 14 may change from the inner diameter side to the outer diameter side, and in that case, the maximum depth H is preferably in the range of 0.1 to 1.0 mm.

For example, if the maximum depth H of the lubrication groove 14 is constant from the inner diameter side to the outer diameter side, the cross-sectional shape of the lubrication groove 14 is a right triangle, and the angle θ1 (see FIG. 2) is not 0 °, the angle θ2 Increases continuously from the inner diameter side to the outer diameter side.

Although FIG. 3 shows a case where the cross-sectional shape of the lubrication groove 14 is a right triangle, it may be a substantially right triangle. For example, the hypotenuse constituting the groove bottom surface 14a and the side constituting the groove side surface 14b may be slightly curved as long as the effect of the present invention is not impaired. Further, the internal angle at the intersection _v2 between the line segment B and the cut surface may be set to an angle of 70 ° to 90 ° (preferably 80 ° to 90 °). It is preferable that the groove side surface 14b is close to a right angle to the land portion 13. Further, a chamfer or R may be provided at the intersection _{v2 ,} and a corner R may be provided at the intersection v3. The chamfer of the intersection v2 and the size of R are not limited, but in the case of chamfering, it may be, for example, about _C0.1 to 0.2, and in the case of R, it may be, for example, about R0.1 to 0.2. The size of the corner R of the intersection v3 is not limited, but may be, for example, about _R0.1 to 0.2.

Another example of the slide bearing in the present invention is shown in FIG. FIG. 4 is a cross-sectional view of the lubrication groove cut along a plane orthogonal to the line segment A, as in FIG. As shown in FIG. 4, an inclined surface 16c having a steeper slope than the groove bottom surface 16a is provided at the boundary between the end portion on the upstream side of the groove bottom surface 16a in the rotation direction Z and the land portion 15. In this case, the locus of the upstream end of the inclined surface 16c in the rotation direction Z becomes the line segment A. In this example, the inclination angle θ3 of the inclined surface 16c with respect to the land portion 15 may be an angle larger than the angle θ2, for example, 20 ° to 90 °, preferably 40 ° to 60 °. If the angle θ3 has a gentler gradient than 20 degrees, when the land portion 15 is worn, the area change of the land portion 15 becomes large, and there is a possibility that the desired effect cannot be obtained. Further, R may be provided at the intersection v _1'of the inclined surface 16c and the line segment A. A chamfer or R may be provided at the intersection v _2'of the line segment B and the cut surface, and the intersection v _3'of the groove bottom surface 16a and the groove side surface 16b, and the intersection v _4'of the groove bottom surface 16a and the inclined surface 16c may be provided. A corner R may be provided. The size of R at the intersection v _1'is not limited, but may be, for example, about R0.1 to 0.2. The chamfer of the intersection v _2'and the size of R are not limited, but in the case of chamfering, it may be, for example, about C0.1 to 0.2, and in the case of R, it may be, for example, about R0.1 to 0.2. The size of the corner R of the intersection v _3'and v _4'is not limited, but may be, for example, about R0.1 to 0.2.

Subsequently, the effect of the configuration of FIG. 4 is shown in FIG. As shown in FIG. 5A, this slide bearing is provided with an inclined surface 16c having a steeper slope than the groove bottom surface 16a at the boundary between the groove bottom surface 16a and the land portion 15 (sliding surface). Compared with the case where the inclined surface is not provided (FIG. 5 (b)), the increase in the surface area of the sliding surface is small and the change in torque is suppressed even when the sliding surface is worn to the same extent.

In the present invention, the material of the slide bearing is not particularly limited, and synthetic resin, carbon material, metal and the like can be used. Among these, it is preferable to use a synthetic resin, and it is more preferable to use a thermoplastic resin from the viewpoint of ease of molding. In particular, the slide bearing is preferably an injection-molded body of a resin composition containing a thermoplastic resin. At the time of injection molding, at least one gate is arranged on the outer diameter surface of the slide bearing, and the molten resin composition flows into the cavity from the gate. When the gate is a multi-point gate, the distance between the gates is preferably equal in the circumferential direction.

Here, the position of the gate will be described with reference to FIG. The slide bearing 8 in FIG. 2 is an injection-molded body that is injection-molded using three gates (three-point gates) indicated by black arrows, and has a gate mark on the outer diameter surface. The distance between the gates is set to 120 ° in the circumferential direction. The position of the gate is not particularly limited, but as shown in FIG. 2, it is preferable that the weld portion W is formed in the lubrication groove 14 and the weld portion W is not formed in the portion (land portion 13) other than the lubrication groove 14. .. Since the weld portion W is formed near the middle of the adjacent gates, in FIG. 2, the positions of the gates are adjusted so that the three weld portions W are formed in the three lubrication grooves 14.

The weld portion is formed in the portion where the molten resin is merged, and the weld portion may be convex as compared with the portion without the weld portion. Therefore, the flatness of the land portion 13 can be reduced by not forming the weld portion on the land portion 13 of the end surface. When the convex portion caused by the weld portion extends over a wide range around the weld portion, it is not essential that the entire convex portion is contained in the lubrication groove. Further, the position of the weld portion can be confirmed by a known method such as microscopic observation. In the slide bearing 8, the position of the gate in the axial direction is not limited, but it is preferably near the center of the axial length of the slide bearing 8.

Further, the flatness of the land portion 13 is preferably 0.08 mm or less, and more preferably 0.05 mm or less. The flatness is based on the definition of JIS B0621-1984. The flatness measuring method may be either a contact type measurement using a dial gauge or the like, or a non-contact type measurement using height information obtained by irradiating a laser beam or the like. By improving the flatness of the flat portion (land portion 13) excluding the lubrication groove 14 on the bearing end surface of the slide bearing 8, it is possible to reduce the vibration generated during sliding.

In the slide bearing in the present invention, it is preferable to form a groove on the radial sliding surface of the inner diameter surface of the slide bearing in addition to the end surface described above. For example, a linear groove or a spiral groove parallel to the axial direction can be formed. Further, it is preferable to make this groove a dynamic pressure groove. By providing the dynamic pressure groove, it is possible to push water into the closed sliding surface and supply a large amount of water, generate a load in the counterload direction, form a water film, and have a low coefficient of friction. In addition, an air-cooling effect can be expected even in an abnormal state of running out of water. In the spiral groove, by making the spiral rotation direction the same as the rotation direction of the shaft, dynamic pressure is likely to be generated. Further, it is preferable that the groove is a combination of a communication groove (a groove communicating from one end face of the bearing to the other end face) and a non-communication groove.

The resin composition when the slide bearing is an injection molded body will be described below. The base resin of the resin composition is preferably a thermoplastic resin. The type of thermoplastic resin is not limited, but engineering plastics or super engineering plastics are preferable from the viewpoint of heat resistance and chemical resistance. Specific examples thereof include polyphenylene sulfide (PPS) resin, polyetheretherketone (PEEK) resin, polyethersulfone resin, polyetherimide resin, polyamide resin, thermoplastic polyimide resin, polyamideimide resin and the like. Among these resins, PPS resin and PEEK resin, which have particularly excellent chemical resistance and low water absorption rate, are preferable. From the economical point of view, PPS resin is particularly preferable. By using a resin composition using a PPS resin as a base resin, an inexpensive slide bearing can be provided.

The PPS resin is a crystalline thermoplastic resin having a polymer structure in which the benzene ring is connected by a sulfur bond at the para position. The PPS resin has a melting point of about 280 ° C. and a glass transition point of 93 ° C., and has extremely high rigidity, excellent heat resistance, dimensional stability, and wear resistance. The PPS resin has types such as crosslinked type, semi-crosslinked type, linear type, and branched type depending on its molecular structure, but in the present invention, it can be used without being limited to these molecular structures and molecular weights.

The PEEK resin is a crystalline thermoplastic resin having a polymer structure in which a benzene ring is connected to a carbonyl group by an ether bond at the para position. PEEK resin has a melting point of about 340 ° C and a glass transition point of 143 ° C. In addition to excellent heat resistance, creep resistance, load resistance, wear resistance, sliding characteristics, fatigue characteristics, etc., PEEK resin has excellent moldability. Has.

In the above resin composition, it is preferable to add a polytetrafluoroethylene (PTFE) resin in order to impart frictional properties in a drained state in which a water film is not formed. Further, in order to impart frictional properties in circulating water, it is preferable to add graphite. Furthermore, graphite also has the effect of improving the dimensional accuracy of the slide bearing during injection molding. By blending graphite, the flatness of the land portion can also be reduced.

As the PTFE resin, any of a molding powder by a suspension polymerization method, a fine powder by an emulsion polymerization method, and a regenerated PTFE may be adopted. In order to stabilize the fluidity of the resin composition, it is preferable to use regenerated PTFE, which is difficult to be fibrous due to shearing during molding and is difficult to increase the melt viscosity. Regenerated PTFE is a heat-treated (heat-history-added) powder, a powder irradiated with γ-rays, electron beams, or the like. For example, a powder obtained by heat-treating molding powder or fine powder, a powder obtained by further irradiating this powder with γ-ray or electron beam, a powder obtained by crushing a molded product of molding powder or fine powder, and then γ-ray or electron beam. There are types such as irradiated powder, molding powder or fine powder irradiated with γ-ray or electron-beam.

As commercially available PTFE resins that can be used in the present invention, Kitamura Co., Ltd .: KTL-610, KTL-450, KTL-350, KTL-8N, KTL-400H, Mitsui Chemours Fluoro Products Co., Ltd .: Teflon (registered trademark) ) 7-J, TLP-10, AGC: Full-on G163, L150J, L169J, L170J, L172J, L173J, Daikin Industries: Polyflon M-15, Lubron L-5, 3M Japan: Dynion TF9205, TF9207 And so on. Further, it may be a PTFE resin modified with a perfluoroalkyl ether group, a fluoralkyl group, or another side chain group having a fluoroalkyl group. Among the above, as the PTFE resin irradiated with γ-rays or electron beams, Kitamura Co., Ltd .: KTL-610, KTL-450, KTL-350, KTL-8N, KTL-8F, AGC Co., Ltd .: Full-on L169J, L170J , L172J, L173J and the like.

As the graphite (graphite), either natural graphite or artificial graphite may be used. The shape of the particles may be scaly or spherical, but the scaly shape is more preferable because it is less likely to fall off during sliding. Examples of natural graphite include ACP manufactured by Nippon Graphite Industry Co., Ltd., and examples of artificial graphite include KS-6, KS-25, and KS-44 manufactured by Imerys GC Japan.

In the above resin composition, it is preferable to add carbon fiber in order to improve the rigidity, wear resistance and dimensional accuracy of the slide bearing. The carbon fiber may be either pitch-based or PAN-based, which is classified from the raw materials. The average fiber diameter of the carbon fibers is 20 μm or less, preferably 5 μm to 15 μm. With thick carbon fiber exceeding the above range, extreme pressure is likely to occur, the effect of improving load bearing capacity is poor, and if the mating material such as the rotating shaft or thrust receiver is stainless steel, the wear damage of the mating material may increase. There is.

The carbon fiber may be either chopped fiber or milled fiber, but milled fiber having a fiber length of less than 1 mm is preferable, and more preferably, the average fiber length is 20 μm to 200 μm. If it is less than 20 μm, it is difficult to obtain sufficient rigidity and reinforcing effect, and the wear resistance may be inferior. If it exceeds 200 μm, extreme pressure is likely to occur, and if the mating material such as the rotating shaft or the thrust receiver is stainless steel, the wear and damage of the mating material may increase. The average fiber diameter can be measured by an electron microscope or an atomic force microscope usually used in this field. Further, the average fiber diameter can be calculated as a number average fiber diameter based on the above measurement.

Commercially available milled fibers that can be used in the present invention include pitch-based carbon fibers manufactured by Kureha Corporation: Kureha M-101S, M-101F, M-201S, and Mitsubishi Chemical Corporation: Dialead K223HM-200 μm, Dialead K223HM. -50 μm, manufactured by Nippon Graphite Fiber Corporation: HC-600-15M, etc. Examples of similar PAN-based carbon fibers include Toho Tenax Co., Ltd .: Vesfite HT M100 160MU, HT M100 40MU, and Toray Industries, Inc .: Trading Card MLD-30, MLD-300 and the like. Examples of the chopped fiber include pitch-based carbon fiber manufactured by Mitsubishi Resin Co., Ltd .: Dialead K223HE, and PAN-based carbon fiber manufactured by Toray Industries, Inc .: Treca T010-003.

A well-known resin additive may be added to the resin composition to the extent that the effect of the present invention is not impaired. Examples of the additive include friction property improving agents such as boron nitride, molybdenum disulfide and tungsten disulfide, and colorants such as carbon powder, iron oxide and titanium oxide.

As for the compounding ratio in the above resin composition, at least the compounding ratio of PTFE resin and / or graphite is 3 to 30% by volume, more preferably 5 to 20% by volume, and carbon fiber is 5 to 30% by volume, more preferably 10 to 20. It is preferable that the volume is% and the balance is the base resin. Further, it is preferable to use PTFE resin and graphite together.

Each material constituting the above resin composition is mixed by a Henschel mixer, a ball mixer, a ribbon blender or the like, if necessary, and then melt-kneaded by a melt extruder such as a twin-screw kneading extruder to pellet for molding. Can be obtained. The additive may be added by using a side feed when melt-kneading with a twin-screw kneading extruder or the like. A slide bearing is molded by injection molding using these molding pellets.

In the slide bearing device of the present invention, the material of the thrust receiver is not particularly limited, but it is preferable to use metal, and it is more preferable to use stainless steel. Further, the surface of the thrust receiver may be coated with a known coating such as a DLC (Diamond-Like-Carbon) coating or a resin coating.

In the thrust receiver, it is preferable that the directions of the streaks formed by machining the surface sliding with the slide bearing are not concentric circles. For that purpose, it is preferable that this surface is formed by a processing method other than turning. When this surface is formed by turning, the lubrication groove of the slide bearing is at right angles to the direction along the streaks (circumferential direction), so that when the slide bearing and the thrust receiver slide, wear debris is generated. It becomes difficult to discharge to the outer diameter side of the slide bearing. As a result, wear debris may be caught in the sliding surface, and the coefficient of friction may fluctuate greatly.

Specific processing methods other than turning include a method of manufacturing a lathe receiver by pressing a metal steel sheet. This press working is particularly preferable because the directions of the streaks are random. Here, the random direction of the streaks means a state in which the streaks are oriented in different directions, not a state in which the streaks are generally aligned in one direction. Further, as another processing method, even if a processing method such as surface polishing processing in which the streaks are unidirectional is used, it is preferable that the wear powder is less likely to be caught in the sliding surface as described above.

In addition, in FIGS. 1 to 5 above, the bearing end surface of the slide bearing is provided with a lubrication groove for discharging liquid and generating dynamic pressure, but instead of or in addition to this configuration, the sliding surface of the thrust receiver is provided. Similar lubrication grooves may be provided. Further, the circulating water in the water pump is not limited to water, but antifreeze solution, chemical solution, or the like can be suitably used.

The cylindrical test pieces (inner diameter 10 mm, outer diameter 17 mm, height 13 mm) used in Examples 1 to 13 and Comparative Examples 1 to 2 are injected using a resin composition using a PPS resin as a base resin. Made by molding. The resin composition contains 5% by volume of PTFE resin, 15% by volume of graphite, and 10% by volume of carbon fiber, and the balance is PPS resin. The details of each material are as follows.
[PPS resin]
Made by Tosoh: B-042
[PTFE resin]
Made by Kitamura: KTL-610 (regenerated PTFE)
〔Carbon fiber〕
Made by Kureha: Kureka M107T (average fiber length 0.4 mm, average fiber diameter 18 μm)
[Graphite]
Made by Imerys GC Japan: KS-25 (artificial graphite, scaly)

FIG. 6 shows a projection drawing of the end faces of the cylindrical test pieces used in Examples 1 to 4 as viewed from the front. In the cylindrical test piece 17 of FIG. 6, the cross-sectional shape of the lubricating groove cut at an arbitrary surface orthogonal to the line segment A is a right triangle, and the maximum depth of the lubricating groove is constant regardless of the radial position. Is. Further, the length of the arc C is longer than the length of the arc D. In Examples 1 to 4, since the angle θ1 is not 0 °, the groove width of the lubricating groove becomes narrower as it approaches the outer diameter side, and the angle θ2 (see FIG. 3) gradually increases from the inner diameter side to the outer diameter side. growing. In Examples 1 to 4, the vertical length L of the line segment A between the inner diameter side end portion of the line segment A and the inner diameter side end portion of the line segment B was fixed to 1.70 mm.

FIG. 7 shows a projection drawing of the end faces of the cylindrical test pieces used in Examples 5 to 13 as viewed from the front. In the cylindrical test piece 18 of FIG. 7, the cross-sectional shape of the lubricating groove cut at an arbitrary surface orthogonal to the line segment A is a right triangle, and the maximum depth of the lubricating groove is constant regardless of the radial position. Is. Further, the length of the arc C is longer than the length of the arc D. In Examples 5 to 13, the line segment A and the line segment B are parallel (angle θ1 = 0 °), and the angle θ2 is constant from the inner diameter side to the outer diameter side. Further, in Examples 5 to 13, the length L was changed.

FIG. 8 shows a projection drawing of the end face of the cylindrical test piece used in Comparative Example 1 as viewed from the front. In the cylindrical test piece 19 of FIG. 8, the cross-sectional shape of the lubricating groove cut at an arbitrary surface orthogonal to the line segment A is a right triangle, and the maximum depth of the lubricating groove is constant regardless of the radial position. Is. Further, the length of the arc C is shorter than the length of the arc D. Therefore, the groove width of the lubricating groove becomes wider as it approaches the outer diameter side, and the angle θ2 gradually becomes smaller.

FIG. 9 shows a projection drawing of the end face of the cylindrical test piece used in Comparative Example 2 as viewed from the front. The cylindrical test piece 20 of FIG. 9 is not provided with a lubrication groove on the end face.

The flatness of the land portion of each of the prepared cylindrical test pieces (according to JIS B0621-1984) was measured with a dial gauge. In addition, the presence or absence of weld in the land portion was observed with an optical microscope.

Using the prepared cylindrical test piece and disk-shaped mating material (SUS304), the coefficient of dynamic friction in the antifreeze liquid (ethylene glycol 50%: water 50%) was measured by a ring-on-disk type tester. In Examples 1 to 11 and Comparative Examples 1 to 2, the test conditions are a speed of 125 m / min, a load of 38 N, and a temperature of 30 ° C., and the disc-shaped mating material has a surface that slides on the cylindrical test piece. The finish was surface polishing. The dimensions and test results of each cylindrical test piece are shown in Tables 1 and 2. The cylindrical test piece shown in Table 1 shows a minimum value and a maximum value because the angle θ2 changes continuously in the radial direction.

As shown in Table 1, Example 1 (θ2 = 10 to 16 °), Example 2 (θ2 = 10 to 23 °), and Example 4 (θ2 = 10 to 43 °) all have an angle of θ2. The minimum value is 10 °, the maximum depth is 0.3 mm, and the setting of the angle θ1 is different. Example 1 (θ1 = 10 °) and Example 2 (θ1 = 15 °) had lower friction than Example 4 (θ1 = 20 °). Further, in Example 3 (θ2 = 16 to 36 °, maximum depth = 0.5 mm), θ2 was larger than that of Examples 1 and 2, and the coefficient of dynamic friction was high. It is considered that this is because the effect of generating dynamic pressure is reduced by increasing θ2. On the other hand, in Comparative Example 1 (θ2 = 7 to 10 °), although θ2 is small, the length of the arc C is shorter than the length of the arc D (C <D), and the groove width expands toward the outer diameter side. The pressure generation effect decreased. As a result, the coefficient of dynamic friction of Comparative Example 1 was higher than that of Examples 1 and 2 and Examples 5 to 11.

Further, as shown in Table 2, in Examples 5 to 11, the line segment A and the line segment B are parallel to each other, and the angle θ2 and the maximum depth are different. Examples 5 to 6 and Examples 8 to 11 in which θ2 is 5 to 30 ° and the maximum depth is 0.1 to 0.6 mm have a dynamic friction coefficient of 0.031 to 0.043 and low friction. Met. On the other hand, the dynamic friction coefficient of Example 7 having a flatness of 0.09 mm was 0.051, which was a slightly higher value. Further, Comparative Example 2 had no lubricating groove on the end face, and the dynamic friction coefficient was 0.066, which was higher than that of any of the Examples. Further, in Example 5 and Examples 8 to 11, there was a lubrication groove near the middle of the adjacent gates, and a weld line was formed in the lubrication groove. On the other hand, in Examples 6 and 7, there was a lubrication groove at a position away from the vicinity of the middle of the adjacent gates, and a weld line was formed in the land portion.

Subsequently, in Examples 12 to 13, fluctuations in the dynamic friction coefficient due to differences in the processing method of the disc-shaped mating material were measured using cylindrical test pieces having the same shape shown in Table 3. In Example 12, the surface of the disc-shaped mating material that slides on the cylindrical test piece was finished by surface polishing. The streaks on the surface after this processing were almost aligned in one direction. In Example 13, the surface of the disc-shaped mating material that slides on the cylindrical test piece is finished by turning. The streaks on the surface after this processing were formed concentrically. The test conditions were the same as in Examples 1 to 11 and Comparative Examples 1 to 2, and the fluctuations in the dynamic friction coefficient for 600 seconds were shown in FIGS. 10 (12) and 11 (13), respectively. ).

Comparing FIGS. 10 and 11, in FIG. 10 (Example 12) in which the disc-shaped mating material is flat-polished, the fluctuation of the dynamic friction coefficient is small, whereas the disc-shaped mating material is turned. In No. 11 (Example 13), an increase in the dynamic friction coefficient due to the biting of wear debris was observed around 160 seconds. In each case, the value of the dynamic friction coefficient was low.

Since the sliding bearing device of the present invention has excellent low friction characteristics and quietness, it circulates cooling water for automobile engines, inverters, batteries, fuel cells, etc., and circulates hot water for water heaters, floor heating equipment, etc. It can be suitably used as a sliding bearing device for a water pump. The slide bearing device of the present invention is not limited to a water pump that circulates water, but is also useful as a pump that transfers and supplies water. Further, the same effect can be expected even if the medium is a pump that circulates and moves and supplies a chemical solution other than water, a solvent, an oil, a liquid such as a beverage, and the like.

1 Water pump 2 Winding 3 Permanent magnet 4 Impeller 5 Shaft 6 Casing 7 Cover 8, 8'Sliding bearing 9 Thrust plate 10 Thrust plate 11 Packing 12 Motor 13 Land part 14 Lubrication groove 15 Land part 16 Lubrication groove 17 Cylindrical test Piece 18 Cylindrical test piece W Weld part

Claims (9)

Each of the impeller, the shaft for supporting the impeller, the cylindrical plain bearing fixed to the impeller for rotatably supporting the impeller with respect to the shaft, and the plain bearing. It is used for a water pump that includes a thrust receiver that slides on the end face, a casing that houses the impeller and forms a pump chamber, and a cover, and that sucks and discharges circulating water through the pump chamber by rotating the impeller. A plain bearing device for water pumps
The slide bearing device for a water pump comprises the slide bearing and the thrust receiver, and has a land portion serving as a sliding surface and an inner diameter on at least one end surface of the slide bearing or at least one member of the thrust receiver. A lubricating groove for discharging the circulating water is provided from the side to the outer diameter side.
The lubrication groove has an inclined surface inclined with respect to the land portion, and has an inclined surface.
In the projection view when the end surface provided with the lubrication groove is viewed from the front, the lubrication groove has a line segment A and a line segment B connecting from the inner diameter side to the outer diameter side of the end face, and an arc along the inner diameter surface. A slide bearing device for a water pump, comprising a region surrounded by C and an arc D along an outer diameter surface, wherein the length of the arc C is equal to or longer than the length of the arc D. The slide bearing device for a water pump according to claim 1, wherein the angle formed by the line segment A and the line segment B is 0 ° to 15 °. The line segment A is located on the upstream side in the relative rotation direction with respect to the line segment B.
In the lubricating groove, the cross-sectional shape of an arbitrary cut surface orthogonal to the line segment A is a substantially right-angled triangle having the inclined surface as a hypotenuse, and the intersection of the line segment A and the cut surface is a vertex. The sliding bearing device for a water pump according to claim 1 or 2, wherein the angle of the internal angle is 3 ° to 30 °. The slide bearing device for a water pump according to any one of claims 1 to 3, wherein the maximum depth of the lubricating groove is 0.1 mm to 1.0 mm. The slide bearing device for a water pump according to any one of claims 1 to 4, wherein a plurality of the lubricating grooves are arranged on the end face at intervals in the circumferential direction. The member on which the lubrication groove is formed has an axial center on an extension line of the line segment A, and the plurality of lubrication grooves are downstream of the center line passing through the line segment A of the member in a relative rotational direction. The slide bearing device for a water pump according to claim 5, wherein the slide bearing device is provided at a position offset to the side. The slide bearing is an injection molded body of a resin composition, and has the lubrication groove on at least one end face thereof.
A claim characterized in that a gate mark is formed on the outer diameter surface of the slide bearing, a weld portion is formed in the lubrication groove in the slide bearing, and the weld portion is not formed in the land portion. The plain bearing device for a water pump according to any one of items 1 to 6. The slide bearing device for a water pump according to any one of claims 1 to 7, wherein in the thrust receiver, the directions of the lines formed by machining the surface sliding with the slide bearing are not concentric circles. The slide bearing device for a water pump according to claim 8, wherein the direction of the streaks is random.

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