JP2006090489A - Deep groove ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deep groove ball bearing capable of reducing friction among a rolling element, a cage and an outer ring, and further reducing heat generation. <P>SOLUTION: The cage 4 is composed of two sheets of annular bodies 6, 6 formed by molding a resin. Two sheets of annular bodies 6, 6 have the shape formed by alternately arranging arc-shaped pocket wall parts 7 having semispherical pocket faces 7a, and connection plate parts 8 extended in the circumferential direction from end parts of the pocket wall parts 7, in the circumferential direction. Two sheets of annular bodies 6, 6 are combined by connecting the connection plate parts 8 with each other in a state of forming pockets 9 for holding balls 3 respectively between the pocket faces 7a. An inner ring 2 is constituted to be rotated. This deep groove ball bearing is constituted to guide the cage 4 by bringing external diameter-side parts of the pocket faces 7a of the cage 4 into contact with the balls 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a deep groove ball bearing, and more specifically, when used as a bearing for supporting a rotor of a motor, it is possible to further increase the speed and extend the service life by suppressing the temperature rise of the bearing portion, and to consume the motor. The present invention relates to a deep groove ball bearing for a motor capable of reducing power loss.

A deep groove ball bearing is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-343567. The deep groove ball bearing disclosed in this publication is a rolling element guide system in which a cage is guided by rolling elements (balls). However, it is a method of guiding the cage by bringing the inner diameter side portion of the cage pocket surface into contact with the rolling element (inner diameter constraint method), or holding the outer diameter side portion of the pocket surface of the cage in contact with the rolling element. There is no clear description in this gazette as to whether it is a system for guiding the vessel (outer diameter restraint system).
JP 2003-343567 A

  Generally, a motor (rotor support) bearing is used for inner ring rotation. The cage used for the motor (rotor support) bearing is a rolling element guide type cage, and the cage is guided by bringing the inner diameter side portion of the pocket surface of the cage into contact with the rolling element (inner diameter). The restraint method is common.

  However, the combination of the inner ring rotation and the inner diameter restraint system has a problem that the friction between the rolling elements, the cage and the outer ring increases, and the amount of heat generation increases. Hereinafter, a mechanism for increasing the heat generation amount will be described.

  In general, a cage is a portion of the pocket surface that is in the bearing load zone and precedes the rotational direction and is in sliding contact with the rolling element to rotate by obtaining a driving force from the rolling element.

  As shown in FIG. 11, if the cage 4 is an inner diameter restraint system, the force F1a acting on the cage 4 from the rolling element 3a in the driving unit A1 of the cage 4 is the rolling element 3b having no cage driving force. It is pressed against the outer ring 1 that is stationary through the cage 4. At this time, since the restraint part B1 of the cage 4 acts as a brake against the rotation of the rolling element 3b, the rolling element 3b pressed against the outer ring 1 acts as a brake (F1b) against the rotation of the cage 4. As a result, forward and reverse forces F1a and F1b act on the retainer 4, and the force acting on the drive part A1 overcomes the braking force on the restraint part B1, so that the drive force on the drive part A1 further increases. In this way, the frictional force at the drive part A1 and the restraint part B1 increases, so the amount of heat generation increases.

  Further, since the rolling element 3 b is pressed against the stationary outer ring 1, the rolling element 3 b is not in contact with the inner ring 2, which is a rotating wheel, and cannot receive a moment for rotating the rolling element from the inner ring 2. Therefore, there is a concern about heat generation due to the frictional force between the outer ring 1 and the restraining portion B1 and the rolling elements 3b braked for rotation and revolution.

  Since grease-filled types are usually used for motor bearings, if the amount of heat generated increases, the grease deteriorates and the bearing life (motor life) is shortened. Further, the higher the rotational speed, the greater the amount of heat generated, so the above problem becomes significant.

  Furthermore, bearing heat generation can be considered as heat generation due to friction inside the bearing, and when the amount of heat generation is large, the friction force inside the bearing is also large. A large frictional force is equivalent to a large bearing rotational torque, and there is a problem that the power consumption loss of the motor becomes large.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a deep groove ball bearing that can reduce the friction of the rolling elements, the cage and the outer ring, and can also reduce the heat generation amount.

  The deep groove ball bearing of the present invention includes an inner ring, an outer ring disposed on the outer peripheral side of the inner ring, a plurality of balls disposed between the inner ring and the outer ring, and a cage that holds each of the plurality of balls. In a deep groove ball bearing having a sealing plate disposed at both ends of an annular space formed between the inner circumference of the outer ring and the outer circumference of the inner ring, the cage is composed of two resin-molded annular bodies. Each of the annular members has a shape in which arc-shaped pocket wall portions having hemispherical pocket surfaces and coupling plate portions extending in the circumferential direction from the end portions of the pocket wall portions are alternately provided in the circumferential direction. The two annular bodies are combined by combining the coupling plate portions with each other so as to form a pocket for holding the ball between the pocket surfaces, the inner ring is configured to rotate, and the cage Guide the cage by bringing the outer diameter side of the pocket surface into contact with the ball That has been made is characterized in.

  According to the deep groove ball bearing of the present invention, by adopting an outer diameter restraining system in which the outer diameter side portion of the pocket surface of the cage is brought into contact with the rolling element to guide the cage, the cage, the rolling element, and the rolling element Sliding between each part with the starting wheel can be reduced, and the frictional heat can be reduced. As a result, it is possible to reduce an increase in the temperature of the bearing portion during rotation, further increase the speed and life, and reduce power consumption loss.

  In the deep groove ball bearing described above, the inner ring is preferably configured to rotate together with the rotor of the motor.

  As a result, it is possible to obtain a motor that can increase the rotational speed and extend the life, and can reduce power consumption loss.

  As described above, according to the deep groove ball bearing of the present invention, the friction of the rolling elements, the cage and the outer ring can be reduced, the heat generation amount can be reduced, the rotational speed can be increased and the life can be extended, and the power consumption can be increased. Loss can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing a configuration of a deep groove ball bearing according to an embodiment of the present invention. FIG. 2 is a schematic perspective view showing the configuration of the cage of the deep groove ball bearing of FIG. 3 is a cross-sectional plan view showing a part of the cage shown in FIG. 1, and FIG. 4 is a longitudinal front view of FIG.

  Referring to FIG. 1, the deep groove ball bearing has an outer ring 1, an inner ring 2, a plurality of balls 3, a cage 4, and a sealing plate 5. The outer ring 1 is disposed on the outer peripheral side of the inner ring 2. A plurality of balls 3 are arranged between the outer ring 1 and the inner ring 2. Each of the plurality of balls 3 is held by a cage 4. Openings at both axial ends of the annular space formed between the inner periphery of the outer ring 1 and the outer periphery of the inner ring 2 are closed by sealing plates 5 such as shield plates attached to both ends of the inner periphery of the outer ring 1. A lubricating grease is sealed between the sealing plates 5. The inner ring 1 is configured to rotate together with the rotor of the motor, and is fitted on a shaft 50 connected to the rotor.

  2 to 4, the cage 4 includes two annular bodies 6 and 6. Each of the two annular bodies 6, 6 has an undulating shape in which arc-shaped pocket wall portions 7 and coupling plate portions 8 extending in the circumferential direction from the end portions of the pocket wall portions 7 are alternately formed in the circumferential direction. And made of a synthetic resin molded product.

  As a synthetic resin material, a polyamide resin such as PA66 or PA46 or a synthetic resin having good slipperiness such as polyphenyl sulfide resin is adopted, and fiber reinforcing material such as glass fiber is mixed as necessary.

  A hemispherical pocket surface 7a along the outer periphery of the ball 3 is formed on the inner periphery of the pocket wall portion 7, and arcuate surfaces 7b are provided at both ends of the pocket surface 7a.

  The two annular bodies 6, 6 are combined so that the pocket surfaces 7a face each other, and are connected and integrated by connecting the connecting plate portions 8 that abut each other. By connecting the annular bodies 6 and 6, a pocket 9 is formed between the opposed pocket surfaces 7a, and a groove-like grease reservoir 10 extending in the cage radial direction is formed between the opposed arc surfaces 7b.

  When connecting the two annular bodies 6, 6, a pin hole 11 is formed in the coupling plate portion 8 that abuts each other, and the tip of the rivet 12 inserted into the pin hole 11 is crimped. Yes.

  Of particular note in the present embodiment, the deep groove ball bearing described above is of the outer diameter restraining system, and the outer diameter side portion of the pocket surface 7a of the cage 4 is brought into contact with the ball 3 to guide the cage 4. It is configured as follows.

  According to the present embodiment, since the outer diameter restraining method is adopted, the friction between the rolling elements, the cage and the outer ring is reduced, and the heat generation amount can be reduced. Hereinafter, a mechanism for reducing the heat generation amount will be described.

  FIG. 5 is a diagram for explaining that the amount of heat generation is reduced in the deep groove ball bearing according to the embodiment of the present invention. Referring to FIG. 5, when the outer diameter restraint type rolling element guide retainer 4 is used in the inner ring rotation, the force F2a acting on the retainer 4 from the rolling element 3a in the drive unit A1 has a retainer driving force. The rolling element 3c not to be pressed is pressed against the inner ring 2 which is a rotating wheel through the cage 4. Since the inner ring 2 is rotating, the rolling element 3c positively starts to rotate by being pressed against the inner ring 2.

  In addition, when the rolling element 3 c is pressed against the inner ring 2 by the cage 4 and the rotation of the rolling element 3 c is braked, the rolling element 3 c tries to revolve together with the inner ring 2. As a result, in any case, this frictional force acts in a direction that contributes to the revolution of the cage 4 (F2b). In this case, unlike the inner diameter restraining method described above, only the forward force acts on the cage 4, and the frictional force at the restraining portion B1 and the driving portion A1 is reduced. Accordingly, the amount of heat generated is smaller than that of the inner diameter restraint method.

  As described above, the cage 4 is designed so that the inner diameter surface 41 and the outer diameter surface 42 of the cage 4 do not contact the outer circumferential surface 2a of the inner ring 2 and the inner circumferential surface 1a of the outer ring 1, and the rotation of the cage 4 is rotated. By using the rolling element guide system that guides only by the moving body 3, adopting the outer diameter restraining system, and further rotating the inner ring, the amount of heat generated by the deep groove ball bearing can be reduced.

  Next, the example of the design method for setting it as an outer diameter restraint system is given below.

(Example 1)
Referring to FIG. 6, the pitch circle diameter (PCD) Dr of rolling element 3 and the pitch circle diameter Dp of cage pocket 9 are substantially equal, and both pitch circle diameters are the boundary. By making the thickness A of the outer diameter side retainer 4 larger than the thickness B of the inner diameter side retainer 4 (A> B), the distance between the rolling element 3 and the pocket surface 7a (radial direction). C <D at the outer diameter portion C and the inner diameter portion D. By designing in this way, the bearing can be an outer diameter restraint system.

(Example 2)
Referring to FIG. 7, the pitch circle diameter Dp of the cage pocket 9 is made smaller than the pitch circle diameter Dr of the rolling element 3, and the cage on the outer diameter side with the pitch circle diameter Dr of the rolling element 3 as a boundary. 4 and the wall thickness F of the cage 4 on the inner diameter side are substantially equal to each other, the radial distance between the rolling element 3 and the pocket surface 7a is the same between the outer diameter portion G and the inner diameter portion H. G <H. By designing in this way, the bearing can be an outer diameter restraint system.

  The deep groove ball bearing of the present embodiment also has the following effects.

  Referring to FIGS. 2 and 3, the two synthetic resin annular bodies 6 forming the retainer 4 have a waveform in which arc-shaped pocket wall portions 7 and coupling plate portions 8 are alternately continuous in the circumferential direction. As a result, a strong annular body 6 can be obtained. For this reason, by combining and integrating the two annular bodies 6, the highly rigid cage 4 can be formed, and the cage 4 is not deformed by centrifugal force even if the bearing rotates at a high speed.

  Therefore, when the bearing rotates at high speed, the pocket surface 7a does not come into strong contact with the ball 3, or the cage 4 does not interfere with the sealing plate 5 (FIG. 1), and heat generation due to friction at the contact portion is prevented. The temperature rise of the bearing can be suppressed. Further, the rotational resistance of the bearing does not increase, and the outer ring 1 and the inner ring 2 can be rotated relatively smoothly.

  Further, arc surfaces 7b (FIGS. 3 and 4) are formed at both ends of the pocket surface 7a, and the grease reservoir 10 is formed between the arc surfaces 7b opposed in the axial direction, thereby being enclosed in the grease reservoir 10. The contact portion between the ball 3 and the pocket surface 7a can be well lubricated with the grease.

  Since the circular arc surface 7b forming the grease reservoir 10 is provided at both ends of the pocket surface 7a, the annular body 6 becomes a molded product without an undercut, and the molded annular body 6 can be easily formed from the mold that has been opened. Can be taken out.

  Here, since the pocket surface 7a forming the pocket 9 is formed by molding, the pocket 9 with high dimensional accuracy can be obtained, and the management of the pocket clearance 13 (FIG. 3) between the ball 3 and the pocket 9 is easy. It is.

  Next, another example of the deep groove ball bearing of the present embodiment will be described.

  FIG. 8 is a view corresponding to a cross-sectional plan view showing a part of the cage of FIG. 1 showing the structure of another example of the deep groove ball bearing in one embodiment of the present invention. Referring to FIG. 8, the configuration of this example is illustrated in that the retainer 4 has recesses 14 at both ends of the pocket surface 7a, and the grease reservoir 10 is formed between the recesses 14 facing in the axial direction. 1 to 4 different from the configuration shown in FIG.

  Since the configuration other than this is almost the same as the configuration shown in FIGS. 1 to 4 described above, the same members are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 8, by forming the grease reservoir 10 by forming the recess 14, the grease reservoir 10 having a large volume can be formed, and the contact portion between the ball 3 and the pocket surface 7a can be well lubricated over a long period of time. be able to.

  Hereinafter, the result of the comparative test performed in order to demonstrate the effect of this invention is demonstrated.

  As test bearings, a bearing A of the present invention example and a bearing B of a comparative example were prepared. The bearing A of the present invention is a deep groove ball bearing of an outer diameter restricting method of a reference number 6308 in JIS (Japanese industrial standard), and the bearing B of a comparative example is a deep groove ball of an inner diameter restricting method (conventional type) of a reference number 6308 in JIS. A bearing was used.

  The test conditions were radial load Fr = 50 kgf, axial load Fa = 10 kgf (spring pressure), rotational speed n = 3,000 to 15,000 rpm, rotating wheel as inner ring, and grease (urea system) for lubrication. Using.

The results obtained by this test are shown in FIGS. FIG. 9 shows the result of the bearing A (outer diameter restraint system) of the present invention example, and FIG. 10 shows the result of the bearing B (inner diameter restraint system) of the comparative example. From the results of FIGS. 9 and 10, the temperature rise at the time of temperature stabilization when the shaft rotation speed is 15000 min ⁻¹ was about 33 ° C. in the bearing A (outer diameter restraint system) of the present invention example. The temperature was about 50 ° C. with the bearing B (inner diameter restraint system) of the comparative example. From this, in the bearing A of the present invention example, the temperature rise was about 20 ° C. lower than that of the bearing B of the comparative example, and a low temperature rise effect was recognized.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The deep groove ball bearing of the present invention can be particularly advantageously applied to a rotor support bearing for a motor that requires high speed, long life, and low power consumption loss.

It is a schematic sectional drawing which shows the structure of the deep groove ball bearing in one embodiment of this invention. It is a schematic perspective view which shows the structure of the holder | retainer of the deep groove ball bearing of FIG. It is a cross-sectional top view which shows a part of holder | retainer shown in FIG. It is a vertical front view of FIG. It is a figure for demonstrating that the emitted-heat amount decreases in the deep groove ball bearing in one embodiment of this invention. It is a figure for demonstrating Example 1 of the design method for setting it as an outer diameter restraint system. It is a figure for demonstrating Example 2 of the design method for setting it as an outer diameter restraint system. It is a figure corresponding to the cross-sectional top view which shows a part of cage | basket of FIG. 1 which shows the structure of the other example of the deep groove ball bearing in one embodiment of this invention. It is a figure which shows the test result of the bearing A (outer diameter restraint system) of the example of this invention. It is a figure which shows the test result of the bearing B (inner diameter restraint system) of a comparative example. It is a figure for demonstrating the mechanism in which the emitted-heat amount increases in the combination of inner ring | wheel rotation and an internal diameter restraint system.

Explanation of symbols

  1 outer ring, 1a inner circumferential surface, 2 inner ring, 2a outer circumferential surface, 3, 3a, 3b, 3c ball (rolling element), 4 cage, 5 sealing plate, 6 annular body, 7 pocket wall, 7a pocket surface, 7b Arc surface, 8 coupling plate portion, 9 pocket, 11 pin hole, 12 rivet, 14 recess, 41 inner surface, 42 outer surface, A1 drive unit, B1 restraint portion, C outer diameter portion, D inner diameter portion.

Claims (2)

An inner ring, an outer ring disposed on the outer circumferential side of the inner ring, a plurality of balls disposed between the inner ring and the outer ring, a cage for holding each of the plurality of balls, and an inner circumference of the outer ring In the deep groove ball bearing having a sealing plate disposed at both ends of the annular space formed between the outer ring and the outer periphery of the inner ring,
The cage is composed of two resin-molded annular bodies, and each of the two annular bodies has an arcuate pocket wall portion having a hemispherical pocket surface and a circumferential direction from an end portion of the pocket wall portion. And the two annular bodies are connected to each other so as to form a pocket for holding the ball between the pocket surfaces. Are combined and combined,
The deep groove is configured to rotate the inner ring, and is configured to guide the cage by bringing an outer diameter side portion of the pocket surface of the cage into contact with the ball. Ball bearing.   The deep groove ball bearing according to claim 1, wherein the inner ring is configured to rotate together with a rotor of a motor.

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