JP2024073241A - Recess processing device, recess processing method, and bearing outer ring manufacturing method - Google Patents

Abstract

[Problem] To provide a flank machining device, flank machining method, and bearing outer ring manufacturing method that can reduce machining time and stably form a flank with simple modification of an existing grinding device. [Solution] A flank machining device that machines a flank having a curvature different from the curvature of the outer diameter surface on a part of a workpiece having a cylindrical outer diameter surface. The device is equipped with a processing tool that grinds or cuts the outer diameter surface of the workpiece, and a chuck mechanism that chucks the workpiece in a state where the axis of the workpiece is eccentric in the direction in which the processing tool approaches or moves away from the spindle. The workpiece is rotated eccentrically with respect to the spindle rotation center, and the processing tool that rotates around the rotation axis makes it possible to cut a fixed amount from the eccentric apex, which is the processing tool contact point. [Selected drawing] Figure 5

Description

The present invention relates to a recess processing device, a recess processing method, and a bearing outer ring manufacturing method.

When grinding the outer peripheral surface of a workpiece whose cross section perpendicular to the rotation axis is non-circular, conventionally, an NC machine tool is used to perform creep feed grinding while controlling the relative positions of the workpiece and the grinding wheel in accordance with the rotation phase of the workpiece spindle (Patent Document 1).

Creep feed grinding is a type of grinding process in which, instead of moving the table at a very slow speed, the workpiece is machined in one pass by applying a cutting depth tens to hundreds of times that of normal grinding.

In a bearing device that supports the shaft of an automobile transmission in a housing via a rolling bearing, the outer race of the rolling bearing is clearance-fitted into the housing to facilitate assembly into the housing. For this reason, the outer race can creep due to unbalanced loads on the shaft when under load or at high speeds.

The mechanism of creep is known to be that a traveling wave is generated on the surface of the raceway, which moves the raceway itself. In other words, when the rolling element load acts on the raceway surface of the raceway, the surface of the raceway protrudes and undulates directly below it. When the bearing rotates, the rolling elements also revolve, so the undulations on the surface become traveling waves. The traveling wave generated on the surface of the raceway behaves like a peristaltic motion in the circumferential and radial directions throughout the load zone of the rolling bearing. The traveling wave attempts to move the mating member in the opposite direction to the revolution direction of the rolling elements, but is pushed back by the resistance of the mating member (shaft or housing), resulting in creep in which the raceway rotates in the revolution direction of the rolling elements, i.e., in the same direction as the bearing rotation.

Therefore, in the past, there have been designs that suppress creep by forming a relief surface on part of the outer circumferential surface of the raceway (Patent Document 2 and Patent Document 3). In other words, by forming such a relief surface, a radial gap can be left between the raceway and the mating member in the load range when the maximum radial load within the range of radial loads that can be applied to the rolling bearing is applied.

In this case, the clearance surface is made to be a substantially arcuate surface, the radius of curvature of which is set to be greater than the radius of curvature of the outer peripheral surface (mating surface) of the raceway, and the center line (center of curvature) of the arcuate surface is set to be shifted in one radial direction from the center line of the mating surface.

Patent No. 5425570 JP 2020-45987 A JP 2020-165498 A

When attempting to form the flanks described in Patent Document 2 and Patent Document 3 on a part of the outer diameter surface, which is a cylindrical surface, by creep feed grinding as described in Patent Document 1, it is necessary to adjust the timing of the rotation of the spindle and the rotation of the grinding wheel, which is not an easy adjustment to make. In addition, since the load is large (high) during machining, when forming the flanks on a workpiece with a perfect circle shape, if the workpiece is thin, there is a risk of the roundness deteriorating during machining. For this reason, it is difficult to form the flanks by creep feed grinding as described in Patent Document 1. In addition, while it is possible to machine a perfect circle shape with general collet chuck and shoe centerless machining methods, it is difficult to form an arc portion (flank) with a different curvature on a part of the outer circumference of a perfect circle shape.

In view of the above problems, the present invention provides a flank machining device, a flank machining method, and a manufacturing method for bearing outer rings that can shorten the machining time and can stably form flanks by simply modifying existing grinding equipment.

The flank machining device of the present invention is a flank machining device which machines a flank having a curvature different from the curvature of the outer diameter surface on a part of the outer diameter surface of a workpiece having a cylindrical outer diameter surface, and includes a machining tool which grinds or cuts the outer diameter surface of the workpiece, a chuck mechanism which chucks the workpiece axis in an eccentric state in the direction of approaching or moving away from the machining tool and the spindle, and a machining tool which rotates around the rotation axis by rotating the workpiece eccentrically about the center of rotation of the spindle, allowing a constant amount of cutting from the machining tool contact point, which is the eccentric apex.

According to the flank machining device of the present invention, the workpiece is rotated eccentrically about the center of rotation of the spindle, and a tool rotating about the rotation axis can cut a certain amount from the tool contact point, which is the eccentric apex, so that a flank having a curvature different from the curvature of the outer diameter surface can be machined on a part of the outer diameter surface of the workpiece. In this case, the flank is made to have a substantially arcuate shape, and the radius of curvature is set to be larger than the radius of curvature of the outer diameter surface of the workpiece, and the center line (center of curvature) of the arcuate shape can be set to be shifted in one radial direction from the center line of the outer diameter surface of the workpiece.

In addition, there is no need to adjust the timing of the spindle rotation and the tool rotation, which shortens the overall processing time and does not place a large load on the workpiece during processing. Also, the chuck mechanism only needs to be able to chuck the workpiece axis eccentrically in the direction in which the tool approaches or moves away from the spindle rotation center, so it only requires modification to the spindle side of the workpiece side of a conventional, general, existing grinding device.

The chuck mechanism may be a mechanism for gripping the inner diameter surface of the workpiece, a mechanism for clamping both axial end faces of the workpiece, or a mechanism for gripping the inner diameter surface of the workpiece and clamping both axial end faces of the workpiece. These mechanisms do not interfere with the chuck mechanism machining (grinding) the flank when forming the flank on the outer diameter surface of the workpiece, and can stably rotate the workpiece eccentrically.

The workpiece is preferably the outer race of a rolling bearing. That is, with this relief surface machining device, it is possible to machine a relief surface having a curvature different from that of the outer diameter surface on a part of the outer diameter surface of the race, which is the workpiece. In this case, the relief surface is made to be a substantially arcuate surface, and the radius of curvature is set to be larger than the radius of curvature of the outer peripheral surface (mating surface) of the race, and the center line (center of curvature) of the arcuate surface can be set to be shifted in one radial direction from the center line of the mating surface. As a result, in a bearing device in which an automobile transmission shaft is supported in a housing via a rolling bearing having a race (outer race) with a relief surface machined by this relief surface machining device, creep of the outer race can be stably suppressed.

The flank machining method of the present invention is a method for machining a flank having a curvature different from the curvature of a cylindrical outer diameter surface of a part of the outer diameter surface of a workpiece, in which the workpiece is chucked with the workpiece axis eccentric in the direction of approach/removal between a tool that grinds or cuts the outer diameter surface of the workpiece and a spindle, and the workpiece is rotated eccentrically about the spindle rotation center, and a fixed amount is cut in from the tool contact point, which is the eccentric apex, with the tool that rotates around the rotation axis.

According to the flank machining method of the present invention, the workpiece is rotated eccentrically around the center of rotation of the spindle, and a tool that rotates around the rotation axis can cut a certain amount from the tool contact point, which is the eccentric apex, so that a flank having a curvature different from the curvature of the outer diameter surface can be machined on part of the outer diameter surface of the workpiece.

A contact detection means may be used to detect contact between the tool and the workpiece, and the cutting depth of the grinding wheel may be controlled based on the detection data. By controlling the cutting depth of the tool in this manner, a flank surface with a desired curvature can be formed, and the circumferential length of this flank surface can also be set as desired.

An AE sensor can be used for the contact detection means. AE (acoustic emission) is defined as the phenomenon in which, when a solid body deforms or breaks, the energy stored up until that point is released, and part of it is emitted as elastic waves (AE waves). Therefore, when the grinding wheel comes into contact with the workpiece, AE waves are generated, and these AE waves (elastic waves) can be detected by the AE sensor, making it possible to detect the contact state between the tool and the workpiece. This makes it possible to control the amount of cutting of the grinding wheel into the workpiece.

The manufacturing method of the bearing outer ring of the present invention is a manufacturing method of a bearing outer ring in which a flank surface having a curvature different from the curvature of the outer diameter surface is formed on a part of the outer diameter surface of the cylindrical surface, and the flank surface is formed by chucking the bearing outer ring in a state in which the outer ring axis is eccentric in the direction of approach/removal between the spindle and a processing tool that grinds or cuts the outer diameter surface of the bearing outer ring, rotating the bearing outer ring eccentrically about the spindle rotation center, and cutting a fixed amount from the processing tool contact point, which is the eccentric apex, with a processing tool that rotates around the rotation axis.

The manufacturing method of the outer ring for a bearing of the present invention makes it possible to form an outer ring (outer ring for a bearing) that has a relief surface on part of the outer peripheral surface (outer diameter surface). This makes it possible to stably manufacture bearings (rolling bearings) that can suppress creep of the raceway ring (outer ring).

The present invention is expected to reduce processing time, and can stably form flanks with simple modifications to existing grinding equipment.

FIG. 2 is a perspective view showing a flank machining device according to the present invention, illustrating a main part of the device using a grindstone as a machining tool. FIG. 2 is a front view of a main part of a flank machining device according to the present invention, the device using a grindstone as a machining tool. FIG. 2 is a side view of a main part of a flank machining device according to the present invention, the device using a grindstone as a machining tool. FIG. 1 is a simplified diagram showing the relationship between a workpiece and a grindstone which is a processing tool. FIG. 2 is a simplified configuration diagram of a control unit. FIG. 2 is a front view of a main part of the flank machining device according to the present invention, in which a cutting tool is used as a machining tool. FIG. 13 is a front view of a main part of the flank machining device according to the present invention, in which another cutting tool is used as the machining tool. 1 is a front view of a bearing device using a rolling bearing having an outer raceway on which a flank has been formed using the flank processing device according to the present invention. 10 is a cross-sectional view taken along line XX in FIG. 9. FIG. 10 is an enlarged front view of an outer raceway of the bearing device shown in FIG. 9 . FIG. 12 is a cross-sectional view of the outer race shown in FIG. 11 .

The following describes an embodiment of the present invention with reference to Figures 1 to 12. Figure 9 shows a bearing device using a rolling bearing with an outer raceway whose flank has been formed using the flank machining device of the present invention. This bearing device comprises a shaft 1, a housing 2 surrounding the shaft 1, and a rolling bearing 3 interposed between the shaft 1 and the housing 2. In the following, in an ideal state in which the design rotation centerline of the rolling bearing 3 and the rotation centerline of the shaft 1 coincide, the direction along the center of rotation is referred to as the "axial direction". Also, the direction along the circumference that goes around the rotation centerline is referred to as the "circumferential direction". Also, the direction perpendicular to the rotation centerline is referred to as the "radial direction".

The shaft 1 rotates relative to the housing 2. The shaft 1 is, for example, a transmission shaft provided in an automobile transmission. The shaft 1 has a mating surface 1a extending in the circumferential direction. This mating surface 1a is formed as a cylindrical surface concentric with the rotation center line of the shaft 1. The housing 2 is stationary with respect to the shaft 1 and supports a rolling bearing 3 in the radial direction. The housing 2 is, for example, a partition wall formed as a part of a transmission case of an automobile.

The housing 2 has a mating surface 2a that extends in the circumferential direction. This mating surface 2a is formed as a cylindrical surface that surrounds the mating surface 1a of the shaft 1 from the outside. The center line of the mating surface 2a is set concentrically with the center of rotation of the shaft 1.

The rolling bearing 3 rotatably supports the shaft 1 relative to the housing 2, and bears the radial load acting between the shaft 1 and the housing 2. This bearing device is designed to have a radial load in one direction. When this bearing device is in operation, a radial load is applied to the rolling bearing 3 between the mating surface 1a of the shaft 1 and the mating surface 2a of the housing 2.

The rolling bearing 3 comprises an inner raceway 4 attached to the shaft 1, an outer raceway 5 attached to the housing 2, a number of rolling elements 6 interposed between the raceways 4, 5, and a cage 7 that maintains the circumferential spacing between the rolling elements 6. A deep groove ball bearing is exemplified as the rolling bearing 3.

The inner raceway 4 is an annular bearing component having a raceway surface 4a extending in the circumferential direction on the outer periphery and a mating surface 4b extending in the circumferential direction on the inner periphery. The raceway surface 4a is capable of contacting the rolling elements 6 over the entire circumference with a contact angle of 0°. The mating surface 4b is formed as a cylindrical surface concentric with the mating surface 1a of the shaft 1. The width (axial length) of the mating surface 4b is constant over the entire circumference.

The fit between the mating surface 4b of the inner raceway 4 and the mating surface 1a of the shaft 1 is set to an interference fit with a tightening margin. The inner raceway 4 is fixed by this interference fit so that it rotates integrally with the shaft 1.

The outer raceway 5 is an annular bearing component that has a raceway surface 5a that extends in the circumferential direction on the inner circumference side and a mating surface 5b that extends in the circumferential direction on the outer circumference side. The raceway surface 5a is capable of contacting the rolling elements 6 over the entire circumference with a contact angle of 0°.

The outer raceway 5 is clearance-fitted with the housing 2, which is either the shaft 1 or the housing 2, as the mating member.

Figures 11 and 12 show the shape of the outer raceway 5 in its natural state when no load is applied to the outer raceway 5. The mating surface 5b of the outer raceway 5 is formed in an arc shape. The mating surface 5b defines the outer diameter of the outer raceway 5. The diameter of the mating surface 5b corresponds to the diameter of an imaginary circle C that circumscribes the mating surface 5b. The arc shape of the mating surface 5b is set concentrically with the mating surface 4b of the inner raceway 4 shown in Figures 9 and 10. The width (axial length) of the mating surface 5b is constant around the entire circumference.

The diameter of the mating surface 5b of the outer raceway 5 is smaller than the diameter of the mating surface 2a of the housing 2. The mating surface 5b of the outer raceway 5 and the mating surface 2a of the housing 2 are brought into contact with each other by the radial load applied from the shaft 1 to the rolling bearing 3.

Of the outer raceway 5 and the housing 2, only the outer raceway 5 has a clearance surface 5c that divides the mating surface 5b of the raceway 5 over its entire width. The clearance surface 5c extends over the entire width of the mating surface 5b, completely dividing the mating surface 5b in the circumferential direction.

As shown in FIG. 11, the flank 5c has a maximum radial depth δ at the center of the circumferential length of the flank 5c relative to the diameter of the mating surface 5b that it separates, and the radial depth decreases as the flank 5c moves circumferentially farther from the center. The maximum radial depth δ corresponds to the radial distance between the imaginary circle C and the flank 5c.

In the illustrated example, the relief surface 5c is continuous between both circumferential ends e, e of the dividing mating surface 5b so as to form a substantially arcuate surface along the axial direction. The radius of curvature of the substantially arcuate surface is larger than that of the mating surface 5b, and the center line (center of curvature) of the arcuate surface is set at a position shifted in one radial direction from the center line of the mating surface 5b (downward in FIG. 11).

The circumferential length of the relief surface 5c can be determined by the angle α around the rotation centerline of the shaft 1. Here, when the pitch angle between the rolling elements 6 shown in FIG. 9 is θ, the angle α corresponding to the circumferential length of the relief surface 5c shown in FIG. 11 can be set, for example, to 0<α≦2θ. In order to achieve a shape that suppresses deflection and stress of the outer raceway 5 due to radial load, it is preferable to set it to 0.5θ≦α≦θ.

As shown in FIG. 12, when the minimum radial thickness between the raceway surface 5a and the mating surface 5b of the outer raceway ring 5 is the outer raceway thickness H, the maximum radial depth δ of the relief surface 5c shown in FIG. 11 can be set to, for example, 0.005H≦δ≦0.1H. In order to reduce the deflection and stress of the outer raceway ring 5 due to radial load, it is preferable to set the maximum radial depth δ of the relief surface 5c to 0.01H≦δ≦0.05H.

As shown in Figures 9 and 10, the relief surface 5c creates a radial gap g between the outer periphery of the outer race 5 and the mating surface 2a of the housing 2. The radial gap g is formed by the relief surface 5c, which divides the full width of the mating surface 5b that defines the outer diameter of the outer race 5, so it spans the full width of the mating between the outer periphery of the outer race 5 and the inner periphery of the housing 2 (corresponding to the full width of the mating surface 5b), and forms a space that penetrates axially between the outer periphery of the outer race 5 and the mating surface 2a of the housing 2.

The relief surface 5c is formed so as to leave a radial gap g between the outer circumference of the outer race 5 and the mating surface 2a of the housing 2 in the load range when the rolling bearing 3 is subjected to a maximum radial load F. Here, the maximum radial load F is the largest radial load within the range of variation of the radial load applied to the rolling bearing 3 during operation of this bearing device.

The load bearing area of the rolling bearing 3 that receives the radial load extends over approximately half the circumference of the rolling bearing 3. The circumferential center of the load bearing area is located in the position corresponding to the load direction of the radial load (corresponding to the position on the extension of the arrow direction of the radial load F in FIG. 9). The outer raceway 5 receives the radial load on the raceway surface 5a through the rolling elements 6 in the load bearing area, so elastic deformation occurs. At this time, in the load bearing area of the rolling bearing 3, the mating surface 5b and the relief surface 5c of the outer raceway 5 (especially the area directly below the raceway surface 5a) are deformed in a wavy shape. The radial height of the wavy shape is maximum at the circumferential center of the load bearing area, and decreases the further away from the circumferential center.

The maximum radial depth δ of the flank 5c shown in FIG. 11 is set to be greater than the maximum radial height of the wavy shape described above in the load zone of the rolling bearing 3 when the maximum radial load F is applied. In addition, the radial depth of the flank 5c gradually decreases from the center of the circumferential length of the flank 5c toward the end e of the mating surface 5b so as not to exceed the reduction in the radial height of the wavy shape according to the circumferential position described above.

Note that the radial gap g in Figure 9 and the maximum radial depth δ in Figure 11 are exaggerated. In the actual wavy deformation of the raceway 5, the relative height of the wavy shape to the mating surface 5b is at most on the order of a few μm.

The outer raceway 5 is supported radially at the contact area between the mating surface 5b, which is located within the load-bearing zone of the rolling bearing 3 shown in FIG. 9, and the mating surface 2a of the housing 2. At this contact area, the slight wavy deformation of the mating surface 5b comes into contact with the mating surface 2a. Even when the maximum radial load F is applied to the rolling bearing 3, the reaction force from the mating surface 2a, which is subject to slight wavy deformation at the aforementioned contact area located within the load-bearing zone, is not strong enough to cause the raceway 5 to creep.

Since the radial gap g shown in Figures 9 and 10 is formed by such a relief surface 5c, even if the outer circumference (fitting surface 5b and relief surface 5c) of the outer raceway 5 is deformed in a wavy shape in the load-bearing area of the rolling bearing 3 when the maximum radial load F is applied, the radial gap g remains, and in the circumferential area where the radial gap g remains, the wavy deformation part of the outer raceway 5 and the fitting surface 2a of the housing 2 cannot come into contact. In other words, during operation of this bearing device, in the circumferential area where the radial gap g remains, the wavy deformation part occurring on the outer circumference of the outer raceway 5 does not come into contact with the fitting surface 2a of the housing 2. Therefore, the wavy deformation occurring on the outer circumference of the outer raceway 5 in the load-bearing area of the rolling bearing 3 does not act as a traveling wave that causes the raceway 5 to creep. Therefore, this bearing device can better suppress creep of the raceway 5 compared to the case where the maximum elastic deformation part (wavy deformation part) of the raceway can come into contact with the groove bottom or groove edge of the creep suppression circumferential groove.

Figures 1 to 3 show a flank machining device according to the present invention. This machining device (e.g., a grinding device) can machine a flank 5c having a curvature different from the curvature of the outer diameter surface Wa of a workpiece W (e.g., the outer raceway of the rolling bearing described above, i.e., the outer ring for the bearing) having a cylindrical outer diameter surface Wa on a portion of the outer diameter surface Wa.

As shown in Figures 1 and 5, the processing device is equipped with a grinding wheel 13 as a processing tool 50 arranged on a rotating shaft 11 with its axis O1 parallel to the spindle 12 (axis O of the grinding device body) of the grinding device body S, and a chuck mechanism 15 that chucks the workpiece axis WO in an eccentric state in the direction of approaching and separating the rotating shaft 11 of the grinding wheel 13 and the center of rotation of the spindle 12. Note that in Figure 1 etc., the processing tool 50 is composed of the grinding wheel 13 and grinds the outer diameter surface Wa of the workpiece W, but in the processing device shown in Figures 7 and 8 described later, the processing tool 50 is composed of a cutting tool 14 and cuts the outer diameter surface Wa of the workpiece W.

The grinding wheel 13 is, for example, a cylindrical body, and is fitted and fixed to the outside of the rotating shaft 11. The grinding wheel 13 is a well-known grinding wheel such as a vitrified grinding wheel, a resinoid grinding wheel, a metal-bonded grinding wheel, or an electroplated grinding wheel, in which general abrasive grains such as fused alumina-based abrasive grains, silicon carbide-based abrasive grains, or ceramic abrasive grains, or superabrasive grains such as CBN abrasive grains or diamond abrasive grains are bonded with an inorganic, organic, or metallic binder. The rotating shaft 11 is driven to rotate by a grinding wheel drive source (drive motor) M1 (see FIG. 6), and the main shaft 12 can be driven to rotate by a main shaft drive source (drive motor) M2 (see FIG. 6). The rotating direction of the rotating shaft 11 and the rotating direction of the main shaft 12 are opposite to each other.

As shown in FIG. 4, the chuck mechanism 15 is a mechanism for gripping the inner diameter surface Wb of a cylindrical workpiece W, that is, an inner diameter gripping chuck mechanism. In this case, it includes a base plate 16 and a plurality of claw members 17 (for example, three as shown in the figure) attached to the base plate 16. Each claw member 17 reciprocates in the radial direction by a reciprocating mechanism not shown. That is, each claw member 17 is positioned on the inner diameter side of the inner diameter surface Wb of the workpiece W, and the workpiece W is placed on the claw members 17 in an externally fitted manner. In this state, each claw member 17 is slid radially outward to press each claw member 17 against the inner diameter surface of the workpiece W, thereby chuck- ing the workpiece W.

As shown in FIG. 1, the base plate 16 is attached to a support plate 20 provided on the tip shaft portion (the shaft portion arranged parallel to the rotating shaft 11 on the grinding wheel side in the same horizontal plane) on the tip side of the spindle 12, and is attached to the support plate 20 so that it can slide horizontally (the direction in which the spindle 12 and the rotating shaft 11 approach or move away from each other in a single horizontal plane). In this case, the support plate 20 and the base plate 16 have insertion holes through which the tip shaft portion is inserted, and the support plate 20 rotates together with the spindle 12.

As shown in FIG. 4, the substrate 16 is provided with a number of long holes 21 extending horizontally, and the support plate 20 is provided with screw holes (not shown) that face the long holes 21. Then, bolt members 22 (see FIG. 1) are screwed into the screw holes via the long holes 21. This allows the horizontal position adjustment of the substrate 16 relative to the support plate 20, and the axis of the substrate 16 can be horizontally displaced relative to the axis of the support plate 20, i.e., the axis O of the main shaft 12.

The base plate 16 has a claw member 17 for gripping the workpiece W on its inner diameter surface, and grips the workpiece W with its axis WO aligned with the axis of the base plate 16. This allows the axis of the workpiece W to be offset by a predetermined amount in the horizontal direction with respect to the axis of the spindle 12. A spacer 24 is interposed between the workpiece W and the base plate 16, and a workpiece holder 25 is attached to the tip of the spindle 12. In other words, the workpiece W is clamped between the spacer 24 and the workpiece holder 25. The workpiece holder 25 is fixed to the tip of the tip of the spindle by a bolt member 26 that is screwed into the tip of the tip.

Figure 6 shows the control section of this flank machining device, and in this device, each drive source M1, M2 is controlled by a computer 30. Here, the computer 30 is basically composed of an input means with an input function, an output means with an output function, a storage means with a storage function, a calculation means with a calculation function, and a control means with a control function. The input function is for reading information from the outside into the computer, and the read data and programs are converted into signals in a format suitable for the computer system. The output function is for displaying the calculation results and stored data to the outside. The storage means stores and saves programs, data, processing results, etc. The calculation function processes data by calculating and comparing according to the program's instructions. The control function decodes the program's instructions and issues instructions to each means, and this control function oversees all the means of the computer. The input means include a keyboard, mouse, tablet, microphone, joystick, scanner, capture board, etc. The output means include a monitor, speaker, printer, etc. The storage means include memory, hard disk, CD/CD-R, PD/MO, etc. The calculation means includes a CPU, and the control means includes a CPU and a motherboard.

As shown in FIG. 6, the device is also provided with a contact detection means 31 for detecting contact between the grinding wheel 13 and the workpiece W. An AE sensor can be used as this contact detection means 31. AE (acoustic emission) is defined as the phenomenon in which, when a solid body deforms or breaks, the energy stored up until that point is released, and part of it is emitted as elastic waves (AE waves). Therefore, when the grinding wheel 13 comes into contact with the workpiece W, AE waves are generated, and these AE waves (elastic waves) can be detected by the AE sensor, thereby making it possible to detect the contact state between the grinding wheel and the workpiece. This makes it possible to control the amount of cutting of the grinding wheel 13 into the workpiece W.

For this reason, the device is equipped with a grindstone cutting depth adjustment mechanism 32, as shown in Figure 6. The grindstone cutting depth adjustment mechanism 32 adjusts the position of the grindstone, and can move the table on which the rotating shaft and drive source are placed.

Next, a method for machining a flank on a part of the outer diameter surface of a workpiece using the flank machining device configured as described above will be described. First, the workpiece W is attached to the tip shaft portion 12a of the spindle 12 with the workpiece W offset by a predetermined amount from the rotation center O of the spindle 12.

In this state, the spindle 12 and the rotating shaft 11 of the grinding wheel 13 are rotated. In this case, as shown in FIG. 5, when the spindle 12 is rotated in the direction of the arrow A, the rotating shaft 11 is rotated in the direction of the arrow B, which is the opposite direction to the direction of the arrow A. Then, the spindle 12 and the workpiece W are rotated multiple times, and this rotation rotates the workpiece W eccentrically with respect to the rotation center O of the spindle 12, and the grinding wheel 13 rotates around the rotation axis 11, and rotates eccentrically with respect to the rotation center of the spindle 12 while allowing a certain amount of cutting h from the grinding wheel contact point T1, which is the eccentric apex P1, so that an arc-shaped escape surface as shown in FIG. 11 can be formed. That is, the part corresponding to the eccentric apex P1 becomes the deepest part by the first rotation processing, and the shape becomes gradually shallower in the clockwise and counterclockwise directions from this eccentric apex P1. That is, the cutting depth gradually becomes deeper (larger) from the point where the grinding wheel 13 comes into contact with the workpiece W, and reaches its deepest point at the eccentric apex, from which point the cutting depth gradually becomes shallower (smaller) until the grinding wheel 13 separates from the workpiece W. In the second and subsequent rotations, machining is repeated with the same cutting depth and machining allowance, and by rotating multiple times, the flank 5c as shown in FIG. 11 is machined.

In the flank machining device, the contact detection means 31 detects contact between the grinding wheel 13 and the workpiece W, and controls the cutting depth of the grinding wheel based on the detection data, so that a flank 5c with a desired curvature can be formed, and the circumferential length of this flank 5c can also be set as desired.

Since an AE sensor can be used for the contact detection means 31, the contact state between the grinding wheel 13 and the workpiece W can be detected stably and reliably, and the amount of cutting of the grinding wheel 13 into the workpiece W can be controlled with high precision.

In the above embodiment, the chuck mechanism 15 is a mechanism for gripping the inner diameter surface Wa of the workpiece W, so that when forming a relief surface on the outer diameter surface of the workpiece W, the chuck mechanism 15 does not interfere with machining (grinding) the relief surface 5c, and the workpiece W can be eccentrically rotated stably.

The chuck mechanism W can be anything that does not interfere with machining (grinding) the clearance surface 5c, so it can be a mechanism that only clamps both axial end surfaces of the workpiece W with the spacer 24 and the workpiece clamp, or a mechanism that grips the inner diameter surface Wc of the workpiece W.

Therefore, according to this flank machining device, the workpiece W is rotated eccentrically with respect to the center of rotation of the spindle 12, and a certain amount of cutting is possible from the grindstone contact point P1, which is the eccentric apex T1, with the grindstone rotating around the rotation axis 11, so that a flank 5c having a curvature different from the curvature of the outer diameter surface Wa of the workpiece W can be machined on a part of the outer diameter surface Wa of the workpiece W. In other words, there is no need to adjust the timing of the cutting of the rotation of the spindle 12 and the rotation of the grindstone 13, which shortens the overall processing time and does not apply a large load during processing. In addition, the chuck mechanism 15 only needs to chuck the workpiece axis Wo in an eccentric state in the direction of approaching and separating the rotation axis 11 of the grindstone 13 and the center of rotation of the spindle 12, so it is only necessary to modify the spindle side of the workpiece side of a conventional, general existing grinding device.

This is expected to reduce processing time, and the flank can be formed reliably with simple modifications to existing grinding equipment.

In the processing device shown in FIG. 1, the processing tool 50 is composed of a grindstone 13, but as shown in FIG. 7, the processing tool 50 may be composed of a cutting tool 14 to grind the outer diameter surface Wa of the workpiece W.

The one shown in Figure 7 has its rotation axis L1 parallel to the main shaft 12, and its outer diameter surface 14a cuts the outer diameter surface Wa of the workpiece W. The other configuration of the processing device shown in Figure 7 is the same as that of the processing device shown in Figure 1 etc., so the same members are given the same reference numerals as those shown in Figures 1 and 2 and their description will be omitted.

For this reason, even in the processing device shown in FIG. 7, by performing the operation of the processing device shown in FIG. 1 etc., the amount of cut gradually becomes deeper (larger) from the point where the cutting tool 14 comes into contact with the workpiece W, and the deepest point is at the eccentric apex, and from this point the amount of cut gradually becomes shallower (smaller) as the cutting tool 14 moves away from the workpiece W.

This allows a clearance surface 5c having a curvature different from the curvature of the outer diameter surface Wa of the workpiece W, which has a cylindrical outer diameter surface Wa, to be machined on a portion of the outer diameter surface Wa.

The one shown in Figure 8 is arranged so that its rotation axis L2 is perpendicular to the spindle 12, and its end face 14b cuts the outer diameter surface Wa of the workpiece W. Therefore, the chuck mechanism 15 in this case chucks the workpiece with the axis center eccentric in the direction in which the end face 14b of the cutting tool 14 approaches or moves away from the center of rotation of the spindle 12. The other configuration of the processing device shown in Figure 8 is the same as that of the processing device shown in Figure 1, etc., so the same members are given the same reference numerals as those shown in Figures 1 and 2, and their explanations are omitted.

For this reason, even in the processing device shown in FIG. 8, by performing the operation of the processing device shown in FIG. 1 etc., the amount of cut gradually becomes deeper (larger) from the point where the cutting tool 14 comes into contact with the workpiece W, and the deepest point is at the eccentric apex, and from this point the amount of cut gradually becomes shallower (smaller) as the cutting tool 14 moves away from the workpiece W.

This allows a clearance surface 5c having a curvature different from the curvature of the outer diameter surface Wa of the workpiece W, which has a cylindrical outer diameter surface Wa, to be machined on a portion of the outer diameter surface Wa.

The flank machining method using the flank machining device of the present invention can constitute a manufacturing method for the outer ring for bearings of the present invention. That is, the outer ring for bearings 5 is chucked with the outer ring axis eccentric in the direction of approach/separation between the tool 50 that grinds or cuts the outer diameter surface of the outer ring for bearings 5 and the spindle 12, and the outer ring for bearings 5 is rotated eccentrically with respect to the spindle rotation center O, and the tool 50 that rotates around the rotation axis O1 cuts in a certain amount from the tool contact point T1, which is the eccentric apex P1, to form the flank 5c. This makes it possible to stably manufacture bearings (rolling bearings) that can suppress creep of the raceway ring (outer ring).

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible. For example, in the embodiment, the chuck mechanism 15 is a so-called three-jaw chuck for gripping the inner diameter, but in this case, the number of jaw members 17 can be freely increased. In addition, the chuck mechanism may be a collet chuck for gripping the inner diameter. The workpiece W is not limited to the raceway of a rolling bearing.

5 raceway 5c clearance 11 rotating shaft 12 spindle 13 grindstone 15 chuck mechanism 31 contact detection means O center of rotation (spindle)
O1 Shaft center (rotation axis)
W Workpiece Wa Outer diameter surface Wb Inner diameter surface Wc, Wd End surface Wo Workpiece axis

Claims (9)

A flank machining device for machining a flank having a curvature different from a curvature of a cylindrical outer diameter surface of a part of the outer diameter surface of a workpiece, the flank machining device comprising:
A flank machining device comprising: a machining tool for grinding or cutting the outer diameter surface of the workpiece; a chuck mechanism for chucking the workpiece in an eccentric state in the direction in which the machining tool approaches or moves away from the spindle; and a machining tool that rotates around the rotation axis by rotating the workpiece eccentrically about the spindle rotation center, allowing a constant amount of cutting from the machining tool contact point, which is the eccentric apex. The flank machining device according to claim 1, characterized in that the chuck mechanism is a mechanism for gripping the inner diameter surface of the workpiece. The flank machining device according to claim 1, characterized in that the chuck mechanism is a mechanism that clamps both axial end faces of the workpiece. The flank machining device according to claim 1, characterized in that the chuck mechanism is a mechanism that grips the inner diameter surface of the workpiece and clamps both axial end surfaces of the workpiece. The flank machining device according to any one of claims 1 to 4, characterized in that the workpiece is the outer race of a rolling bearing. 1. A flank machining method for machining a flank having a curvature different from a curvature of a cylindrical outer diameter surface of a workpiece, the method comprising the steps of:
A flank machining method characterized by chucking the workpiece with the workpiece axis eccentric in the direction of approach/separation between a tool that grinds or cuts the outer diameter surface of the workpiece and a spindle, rotating the workpiece eccentrically about the spindle rotation center, and cutting a fixed amount from the tool contact point, which is the eccentric apex, with the tool that rotates around the rotation axis. The flank machining method according to claim 6, characterized in that a contact detection means detects contact between the tool and the workpiece, and the cutting depth of the grinding wheel is controlled based on the detection data. The flank machining method according to claim 7, characterized in that an AE sensor is used as the contact detection means. 1. A method for manufacturing a bearing outer ring having a flank surface, the flank surface having a curvature different from a curvature of the outer diameter surface, the method comprising the steps of:
A method for manufacturing a bearing outer ring, comprising: chucking the outer ring with the outer ring axis eccentric in the direction of approach/separation between a tool that grinds or cuts the outer diameter surface of the outer ring and a spindle; rotating the outer ring eccentrically about the center of rotation of the spindle; and forming the clearance surface by cutting a fixed amount with a tool that rotates around the rotation axis, the tool contact point being the eccentric apex.

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