JP2007239919A - Sealing type rolling bearing and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive product which secures a smoothness of a sliding surface with which a seal lip comes into slide contact by easy means and has high sealability. <P>SOLUTION: In a manufacturing method of a sealing type rolling bearing which is equipped with an inner ring 10 containing a raceway surface on the outer periphery, an outer ring containing a raceway surface on the inner periphery, a plurality of balls freely rollably interposed between the raceway surfaces on the outer periphery and inner periphery and a sealing device 60 having a seal lip 63 made of an elastic member, a sliding scheduled surface 13 of the inner ring with which the seal lip of the sealing device comes into slide contact is subjected to heat treatment after turning work, thereafter executing superfinishing or grinding and superfinishing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is incorporated in, for example, an electromagnetic clutch device or a pulley device, and is used in an environment where a large amount of foreign matter such as water or muddy water is present, and sealing that requires high sealing performance between the inside and outside of the bearing is required. The present invention relates to a type rolling bearing and a manufacturing method thereof.

  For example, rolling bearings built into electromagnetic clutch devices and various pulley devices prevent foreign matters such as water and dust from entering the bearings or leakage of lubricants such as grease from the bearings. Therefore, a sealed type rolling bearing having a strong sealing property is employed.

  Generally, a rolling bearing is composed of an inner ring having a raceway surface on the outer periphery, an outer ring having a raceway surface on the inner periphery, and a plurality of balls interposed between the raceway surface of the inner ring and the raceway surface of the outer ring. And a cage that is disposed between the inner ring and the outer ring and supports the ball.

  Among these general rolling bearings, a sealed rolling bearing that requires high sealing performance includes a seal device disposed in an annular space formed between an inner ring and an outer ring. When the rolling bearing is rotating on the inner ring, the sealing device includes a cored bar attached to the inner diameter end of the outer ring on the fixed side, and a seal member integrally vulcanized and bonded to the cored bar. The seal member is made of an elastic member such as rubber, and has a seal lip that contacts the outer diameter end of the inner ring at the tip.

In this type of sealed rolling bearing, during operation, the inner ring rotates while maintaining the state in which the seal lip at the tip of the seal member is in sliding contact with the sliding surface which is the outer diameter end of the inner ring. This prevents foreign matters such as water and dust from entering the inside of the bearing or leakage of lubricant such as grease from the inside of the bearing to the outside (for example, see Patent Document 1). FIG. 4 and FIG. 5).
Japanese Patent Laying-Open No. 2005-155882 (FIGS. 4 and 5)

  By the way, in the above-mentioned sealed rolling bearing, the sealing performance mainly affects the seal design itself composed of the structure and material of the seal member and the surface of the sliding surface on which the seal lip of the seal member is in sliding contact. It is a sliding surface design consisting of properties.

  In the above-mentioned sealed rolling bearing disclosed in Patent Document 1, it is desirable that the surface roughness of the sliding surface with which the seal lip is slidably contacted is Rmax 1.2 μm or less in order to improve the sealing performance. Has been.

  On the other hand, in the manufacture of this rolling bearing, it is common to heat-treat in order to ensure the hardness of the sliding surface after the sliding surface of the inner ring that is in sliding contact with the seal lip is turned. When heat treatment is performed after the turning finish of the sliding surface in this way, the scale generated by the heat treatment adheres to the sliding surface.

  The scale by this heat treatment is a strong oxide film (black rust) generated on the sliding surface, which deteriorates the surface roughness of the sliding surface. It becomes very difficult to make the surface roughness Rmax 1.2 μm or less.

  Moreover, in order to remove the scale that deteriorates the surface roughness of the sliding surface, a scale removal process such as barrel polishing is required after the heat treatment. This scale removal processing such as barrel polishing is an off-line operation, which causes an increase in product cost.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to ensure smoothness of the sliding surface with which the seal lip is slidably contacted by a simple means and to have high sealing performance. To provide a sealed type rolling bearing capable of providing an inexpensive product and a method for manufacturing the same.

  As technical means for achieving the above object, the present invention provides an inner member having a raceway surface on the outer periphery, an outer member having a raceway surface on the inner periphery, and a raceway surface and an outer member of the inner member. A plurality of rolling elements interposed between the raceway surface and a raceway surface, and a sealing device disposed in an annular space formed between the inner member and the outer member and having a seal lip made of an elastic member. Further, the sliding surface of the rotating side member that is in sliding contact with the sealing lip of the sealing device is formed by superfinishing after grinding or grinding and superfinishing.

  Further, the present invention is an inner member having a raceway surface on the outer periphery, an outer member having a raceway surface on the inner periphery, and freely rollable between the raceway surface of the inner member and the raceway surface of the outer member. A manufacturing method of a sealed type rolling bearing comprising a plurality of interposed rolling elements and a sealing device having a sealing lip made of an elastic member and arranged in an annular space formed between an inner member and an outer member. The scheduled sliding surface of the rotating side member with which the seal lip of the sealing device is in sliding contact is heat-treated after the turning finishing process, and after that heat treatment, the super-finishing process or the grinding process is performed and then the super-finishing process is performed.

  In this rolling bearing, when the outer member is the fixed side, the inner member is the “rotation side member”, and conversely, when the inner member is the fixed side, the outer member is the “rotation side member”. Become.

  “Super-finishing” is a kind of polishing using a grindstone. For example, a vibration having a frequency of several Hz to several tens of Hz is applied to the grindstone to form a finished surface having a highly accurate surface roughness in a short time. It is a processing method that can. As the grindstone, for example, metal bond superabrasive grains (CBN) are used. In this super-finishing process, by applying vibration to the grindstone, a force from each direction is applied to each abrasive grain, making it easy to crush and drop off the abrasive grains. By processing with, there is little heat generation, and it has the characteristics that processing deterioration is extremely small compared to grinding.

  “Grinding” is a processing method in which the planned sliding surface of the rotating side member is cut by a constant-size cut with a grindstone attached to a grinding machine. The grindstone is a disc in which abrasive grains having a particle size of 1 mm or less with high hardness are hardened with a binder, and this is rotated and brought into contact with the planned sliding surface of the rotating member. The peripheral speed of the grindstone is very high compared to the relative speed of the rotating side member to be processed, and the cutting allowance is as small as several microns, so that it is possible to perform precision processing with a surface roughness of submicron or less. When the rotation side member is an inner member, the planned sliding surface is an outer diameter surface, so cylindrical grinding is performed. When the rotation side member is an outer member, the planned sliding surface is an inner diameter surface. Therefore, it becomes internal grinding.

  In the present invention, the sliding surface of the rotating side member with which the seal lip of the sealing device is slidably contacted is heat-treated after the turning finishing process, and after the heat treatment, the super-finishing process or the grinding process is followed by the super-finishing process. Form. By removing the scale adhering to the planned sliding surface after the heat treatment by super finishing or grinding and super finishing, a smooth sliding surface that is not affected by the scale can be formed.

  In addition, the superfinishing process does not need to be an off-line work like a conventional scale removal process such as barrel polishing, and a series of processes including turning, heat treatment and superfinishing can be performed continuously. Improvements in facilities that affect product costs can be achieved.

  In particular, deformation due to heat treatment can be removed by grinding, and surface roughness can be reduced to Rmax 1.2 μm or less by superfinishing.

  According to the present invention, the sliding surface of the rotating side member with which the seal lip of the sealing device is in sliding contact is heat-treated after turning, and then subjected to super-finishing or grinding and then super-finishing after the heat treatment. Therefore, a smooth sliding surface that is not affected by the scale caused by the heat treatment can be obtained. That is, it is possible to ensure smoothness having a surface roughness equivalent to that of a sliding surface subjected to a conventional scale removal process, and to prevent a reduction in sealing performance.

  In addition, a series of processing consisting of turning, heat treatment, super-finishing or grinding and super-finishing is used because it employs super-finishing that does not require off-line work such as conventional scale removal processing such as barrel polishing. Can be carried out continuously, and the equipment can be improved, which affects the product cost.

  From the above, by adding superfinishing processing or grinding processing and superfinishing processing after heat treatment, the smoothness of the sliding surface with which the seal lip slides can be ensured and a product having high sealing performance can be provided. At the same time, it is possible to provide an inexpensive product by improving the equipment.

  Fig. 1 is a sealed type rolling assembly that is installed in an electromagnetic clutch device, pulley device, etc., and is used in an environment where a large amount of foreign matter such as water and muddy water is present, and that requires high sealing performance between the inside and outside of the bearing. The structure of a bearing is illustrated. FIG. 2 is an enlarged view of a main part of the rolling bearing of FIG.

  As shown in FIG. 1, this sealed rolling bearing is a deep groove ball bearing, and an inner ring 10 as an inner member having a raceway surface 11 on the outer periphery and an outer ring 20 as an outer member having a raceway surface 21 on the inner periphery. And a plurality of balls 30 as rolling elements that are arranged to freely roll between the raceway surface 11 of the inner ring 10 and the raceway surface 21 of the outer ring 20, and a ball disposed between the inner ring 10 and the outer ring 20. Main components are a cage 40 that holds 30 at a predetermined interval in the circumferential direction, and a seal device 60 that is disposed in an annular space 50 formed between the inner ring 10 and the outer ring 20 and has a seal lip made of an elastic member. Yes.

  As shown in FIG. 2, the seal device 60 disposed in the annular space formed between the inner ring 10 and the outer ring 20 has a core mounted on the inner diameter end of the outer ring 20 on the fixed side when the rolling bearing is rotating the inner ring. It consists of a gold 61 and a sealing member 62 integrally vulcanized and bonded to the core bar 61.

  The seal member 62 is made of an elastic member such as rubber, and has a seal lip 63 that contacts the outer diameter end of the inner ring 10 at the tip. The seal lip 63 is composed of a main lip 64 and a sub lip 65 formed by bifurcating.

  The shape of the seal lip 63 is an example, and is not limited to the structure composed of the main lip 64 and the sub lip 65 formed by bifurcating, but may be other shapes.

  On the other hand, a seal groove 12 having a substantially U-shaped cross section is formed at the outer diameter end portion of the inner ring 10 slidably in contact with the seal lip 63, and an inclined slide is formed inside the seal groove 12 (left side in FIG. 2). A surface 13 is provided, and a small-diameter portion 14 as a flange portion of the seal groove 12 is provided on the outer side (right side in FIG. 2).

  In this sealed type rolling bearing, during the operation, the inner ring 10 rotates while maintaining the state in which the seal lip 63 at the tip of the seal member 62 is in sliding contact with the sliding surface 13 at the outer diameter end of the inner ring 10. Specifically, the main lip 64 is in sliding contact with the sliding surface 13 of the seal groove 12, and the sub lip 65 is in sliding contact with the small diameter portion 14 through a slight tightening allowance.

  Since the base portion of the sub lip 65 is formed so as to bend, the waist is weak, and as the main lip 64 is worn, the tightening margin with the small diameter portion 14 is increased following the left side in the figure. Therefore, when the amount of wear of the main lip 64 is small, the rotational torque of the bearing is suppressed, and the tightening margin is increased according to the wear of the main lip 64, so that the sealing performance can be secured.

  Due to the action of the seal lip 63 composed of the main lip 64 and the sub lip 65, it is possible to prevent foreign matters such as water and dust from entering the bearing or lubricant such as grease from the inside of the bearing to the outside. Try to prevent.

  In this embodiment, the case where the outer ring 20 is fixed to a housing (not shown) or the like with the fixed side and the shaft (not shown) is press-fitted into the inner diameter with the inner ring 10 as the rotating side will be described. The present invention is not limited to this, and can also be applied to an outer ring rotating type in which the outer ring 20 is a rotating side and the inner ring 10 is a fixed side. In this case, the seal device 60 is mounted on the outer diameter end of the inner ring 10. Will do.

  By the way, in this sealed type rolling bearing, the sealing performance mainly affects the seal design itself made of the structure and material of the seal member 62 and the inner ring 10 in which the seal lip 63 of the seal member 62 is in sliding contact. The sliding surface design includes the surface properties of the sliding surface 13 and the like.

  In the sealed rolling bearing of this embodiment, the sealing performance is improved by paying attention to the sliding surface design composed of the surface properties of the sliding surface 13 of the inner ring 10. That is, the sliding surface 13 of the inner ring 10 with which the seal lip 63 of the sealing device 60 is in sliding contact is formed by a series of processes including turning, heat treatment, and superfinishing as shown in FIG. The sliding surface 13 can also be formed by a series of processes including turning, heat treatment, grinding, and superfinishing as shown in FIG.

  First, the surface to be slid of the inner ring 10 that is in sliding contact with the seal lip 63 is turned and then heat treated to ensure the hardness of the sliding surface. When heat treatment is performed after the turning finish processing of the planned sliding surface in this way, the scale generated by the heat treatment adheres to the planned sliding surface. The scale by this heat treatment is a strong oxide film (black rust) generated on the planned sliding surface, and deteriorates the surface roughness of the planned sliding surface.

  Therefore, in order to remove the scale that deteriorates the surface roughness of the surface to be slid, superfinishing is performed after superfinishing or grinding after heat treatment.

  Superfinishing is a kind of polishing process using a grindstone, and for example, a vibration having a frequency of several Hz to several tens Hz is applied to the grindstone to form a finished surface having a highly accurate surface roughness in a short time. This is a possible processing method. As the grindstone, for example, metal bond superabrasive grains (CBN) are used.

  Further, the grinding process is a machining method in which the planned sliding surface of the inner ring 10 is cut by a fixed-size cut with a grindstone attached to the grinding machine. Superfinishing is a kind of polishing process using a grindstone, and for example, a vibration having a frequency of several Hz to several tens Hz is applied to the grindstone to form a finished surface having a highly accurate surface roughness in a short time. This is a possible processing method. As the grindstone, for example, metal bond superabrasive grains (CBN) are used.

  In this super-finishing process, by applying vibration to the grindstone, a force from each direction is applied to each abrasive grain, making it easy to crush and drop off the abrasive grains. By processing with, there is little heat generation, and it has the characteristics that processing deterioration is extremely small compared to grinding. By superfinishing, the surface roughness can be reduced to Rmax 1.2 μm or less.

  Further, in this grinding process, abrasive grains having a large hardness of 1 mm or less are hardened with a binder, and a disk-shaped grindstone is rotated and brought into contact with a planned sliding surface of the inner ring 10 for grinding. The peripheral speed of the grindstone is much faster than the relative speed of the inner ring 10, and the machining allowance is as small as several microns, so that it is possible to perform precision machining with a surface roughness of submicron or less. By grinding, deformation due to heat treatment can be removed.

  In this manner, the sliding surface 13 is formed by super-finishing the superficially processed or ground surface after the heat treatment on the planned sliding surface heat-treated after the turning finishing process. The scale adhering to the later planned sliding surface can be removed by super finishing or grinding and super finishing to form a smooth sliding surface 13 that is not affected by the scale. That is, it is possible to ensure smoothness having a surface roughness equivalent to that of a sliding surface subjected to a conventional scale removal process, and to prevent a reduction in sealing performance.

  Superfinishing does not need to be off-line work like conventional scale removal processing such as barrel polishing, and a series of processing consisting of turning, heat treatment, superfinishing, or grinding and superfinishing is continuous. Therefore, it is possible to improve the facilities that affect the product cost.

In embodiment of this invention, it is sectional drawing which shows the structural example of a sealing type rolling bearing. It is a principal part enlarged view of FIG. It is a flowchart which shows an example of the process sequence of the sliding surface of an inner ring | wheel by the method of this invention. It is a flowchart which shows the other example of the process sequence of the sliding surface of an inner ring | wheel by the method of this invention.

Explanation of symbols

10 Inner member [Rotating member (inner ring)]
11 Track surface 13 Sliding surface 20 Outer member (outer ring)
21 raceway surface 30 rolling element (ball)
40 Cage 50 Annular space 60 Sealing device 63 Seal lip

Claims (4)

  An inner member having a raceway surface on the outer periphery, an outer member having a raceway surface on the inner periphery, and a plurality of rolling members interposed between the raceway surface of the inner member and the raceway surface of the outer member. In a sealed rolling bearing comprising a rolling element and a sealing device having a sealing lip made of an elastic member and disposed in an annular space formed between the inner member and the outer member, the sealing lip of the sealing device includes A sealed rolling bearing, wherein a sliding surface of a rotating side member in sliding contact is formed by superfinishing after heat treatment.   An inner member having a raceway surface on the outer periphery, an outer member having a raceway surface on the inner periphery, and a plurality of rolling members interposed between the raceway surface of the inner member and the raceway surface of the outer member. In a manufacturing method of a sealed rolling bearing comprising a rolling element and a sealing device having a sealing lip made of an elastic member and disposed in an annular space formed between the inner member and the outer member, A method of manufacturing a sealed rolling bearing, characterized in that a scheduled sliding surface of a rotating side member in sliding contact with a seal lip is heat-treated after turning finishing and superfinished after the heat treatment.   An inner member having a raceway surface on the outer periphery, an outer member having a raceway surface on the inner periphery, and a plurality of rolling members interposed between the raceway surface of the inner member and the raceway surface of the outer member. In a sealed rolling bearing comprising a rolling element and a sealing device having a sealing lip made of an elastic member and disposed in an annular space formed between the inner member and the outer member, the sealing lip of the sealing device includes A sealed rolling bearing, wherein a sliding surface of a rotating side member that is in sliding contact is formed by grinding and superfinishing after heat treatment.   An inner member having a raceway surface on the outer periphery, an outer member having a raceway surface on the inner periphery, and a plurality of rolling members interposed between the raceway surface of the inner member and the raceway surface of the outer member. In a manufacturing method of a sealed rolling bearing comprising a rolling element and a sealing device having a sealing lip made of an elastic member and disposed in an annular space formed between the inner member and the outer member, A method of manufacturing a sealed rolling bearing, characterized in that a scheduled sliding surface of a rotating side member in sliding contact with a seal lip is heat-treated after a turning finish, and then ground after the heat treatment and then superfinished.

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