TW202300793A - Angular contact ball bearing - Google Patents

Abstract

Provided is an angular contact ball bearing (11) including: an inner ring (12), an outer ring (13), a plurality of balls (14) interposed between the inner ring (12) and the outer ring (13), and a retainer (15) having a cylindrical shape and including pockets (Pt) configured to hold the balls (14) at plurality of positions in a circumferential direction of the retainer. The retainer (15) is guided by the outer ring (13). An inner diameter (Hd) of the retainer (15) has relation to a pitch circle diameter (P.C.D.) of the balls (14) and a ball diameter (Da) : P.C.D.－0.35Da≦Hd≦P.C.D.－0.25Da, and a radial thickness (T) of the retainer (15) has relation to the ball diameter (Da) : 0.40Da≦T≦0.45Da.

Description

Angled ball bearings

This application claims priority based on Japanese Patent Application No. 2021-075067 filed on April 27, 2021, and its entire content is cited as a part of this application.

The present invention relates to angular ball bearings such as those used in machine tool spindles and other equipment.

Bevel ball bearings are widely used in bearings that support high-speed rotating bodies such as the main shaft of machine tools. The retainer of this kind of bevel ball bearing mostly uses the outer ring to guide the retainer or the rolling body to guide the retainer. As for the aforementioned holders, in order to reduce the influence caused by centrifugal force, lightweight resin holders are often used. This kind of holder is aliphatic polyamide resin (nylon), aromatic polyamide resin, polyetheretherketone resin (abbreviated: PEEK material), phenolic resin and other resins reinforced by glass fiber and carbon fiber. The material is formed into a cylindrical shape (for example, Patent Documents 1 to 3).

In order to achieve high efficiency and space saving of machine tools, it is necessary to improve the high-speed rotation and load resistance performance of the angular ball bearing supporting the machine tool spindle. When the bearing rotates at a high speed or under a high load condition, the retainer must have sufficient strength because the retainer receives centrifugal force from the balls and an excessive load following the delay of the balls. [Prior Art Literature] [Patent Document]

Patent Document 1: Japanese Patent Laid-Open No. 2011-117542 Patent Document 2: Japanese Patent Laid-Open No. 2014-95469 Patent Document 3: Japanese Patent Laid-Open No. 2016-145644

(Problem to be solved by the invention)

The basic performance of bevel ball bearings is affected by the ball diameter and the number of balls. If the diameter of the ball is increased or the number of balls is increased, the space that can form the holder becomes smaller, and the holder may not have sufficient strength. In order for the holder to have sufficient strength, it is necessary to increase the wall thickness (radial thickness), axial width, and spacing between cavities of the holder. However, because the basic performance of general bearings is affected by the ball diameter and the number of balls, we propose a retainer shape that ensures the basic performance of the bearing and improves the strength of the retainer in the limited space in the bearing.

The object of the present invention is to provide a bevel ball bearing, which can improve the strength of the retainer while maintaining the size and basic performance of the bevel ball bearing using the outer ring guide retainer. [Technical means to solve the problem]

The oblique ball bearing of the present invention has: an inner ring; an outer ring; a plurality of balls inserted between the inner ring and the outer ring; The cavity at the place; and the above-mentioned retainer is a retainer guide form guided by an outer ring, wherein the outer diameter of the aforementioned retainer is determined as HD, the inner diameter of the aforementioned retainer is determined as Hd, and the diameter of the distance circle between the aforementioned balls is determined as When P.C.D. satisfies the relationship of HD-P.C.D.>P.C.D.-Hd, the inner diameter Hd of the aforementioned holder is determined as the value obtained by subtracting 0.25~0.35 times the diameter Da of the aforementioned balls from the diameter P.C.D between the aforementioned balls. The wall thickness T of the aforementioned retainer is set to be 0.40-0.45 times the diameter Da of the aforementioned ball.

According to this structure, the inner diameter Hd of the outer ring guide holder is set as the value obtained by subtracting 0.25~0.35 times the diameter Da of the ball from the distance circle diameter P.C.D. between the balls. Sufficient distance is secured in the radial dimension up to the inner diameter side. Therefore, the contact ellipse generated by the revolution of the holder and the contact between the ball and the holder does not come into contact with the inner diameter side edge of the cavity of the holder. For example, when the inner diameter Hd of the holder is below P.C.D.-Da×0.20, the aforementioned contact ellipse will touch the inner diameter side edge of the cavity. When the inner diameter Hd of the holder is more than P.C.D.-Da×0.40, in relation to the wall thickness of the holder, sometimes the inner diameter side of the holder is in contact with the inner ring guide of the inner ring, so that the outer ring guide cannot be established. , or when the gap between the inner diameter side of the holder and the outer diameter side of the inner ring becomes relatively narrow, considering the wear of the outer diameter part of the holder when using bearings, it may not be guided by the outer ring or similar to this. status.

Furthermore, the wall thickness T of the holder is set to be 0.40~0.45 times the diameter Da of the ball. Thereby, it is possible to have sufficient retainer strength for the centrifugal force generated under high-speed operation and high load conditions or the load caused by hysteresis of the balls. For example, when the wall thickness T of the holder is Da×0.35 or less, the strength and load resistance of the holder may become insufficient. When the wall thickness T of the holder is greater than Da×0.50, the holder cannot be formed. This is because the desired dimensions required for the shoulders of the inner ring and the shoulders of the outer ring limit the radial area of the retainer. Therefore, in the bevel ball bearing to which the outer ring guides the retainer, the strength of the retainer can be improved while maintaining the size and basic performance of the bearing.

It is also possible to set the axial width HB of the aforementioned retainer within a range that does not protrude from the axial ends of the aforementioned inner ring and the aforementioned outer ring of the oblique ball bearing to be 1.6~2.0 of the diameter Da of the aforementioned balls. times. In the outer ring guide holder, there is a limit to enlarging the holder on the inner diameter side in order to improve the strength and load resistance of the holder. Therefore, the retainer is enlarged by maximizing the utilization of the axial area within the range that does not protrude from the axial ends of the inner ring and the outer ring. In addition, the holder is extended in the axial direction, so that the sliding contact portion between the inner peripheral surface of the outer ring and the outer peripheral surface of the holder is widened, which can increase the stability of the bearing when it rotates.

The inner peripheral surface of the aforementioned retainer may also be provided with an inclined portion inclined so as to approach radially outward as it goes axially outward. In this case, the lubricant can easily flow into the bearing space from the outside of the angular ball bearing along the inclined portion, thereby improving the lubricity.

The above-mentioned retainer may also have: a ball retaining extension part protruding from the inner diameter side edge of the retainer in each cavity to the inner side of the cavity. When the shape of the ball-holding protrusion of the holder embraces the ball in this way, the strength in the circumferential direction of the holder can be ensured, and the strength of the holder can be further enhanced.

The aforementioned retainer may also have a protruding portion protruding radially inward. The outer diameter of the small-diameter side of the aforementioned inner ring is set as d1, the outer diameter of the large-diameter side is set as d2, and the inner diameter of the aforementioned protruding portion is When Hd2 is defined, the relationship of d1<Hd2<d2 is satisfied. By setting the aforementioned relationship, it is possible to maximize the strength of the holder cavity while leaving a necessary margin (necessary gap) for assembling the holder.

The oblique ball bearing of any one of the above-mentioned configurations of the present invention is mounted on an electric vertical take-off and landing aircraft, and the electric vertical take-off and landing aircraft has: a plurality of rotary wings; and a plurality of driving parts, including electric motors for rotating the aforementioned rotary wings; The electric vertical take-off and landing aircraft flies by the rotation of the aforementioned rotary wing, and the aforementioned oblique ball bearing supports the rotating shaft in the aforementioned driving part to be rotatable. In this case, the aforementioned effects of the oblique ball bearing of the present invention can be obtained .

Any combination of at least two structures disclosed in the claims and/or specifications and/or drawings is included in the present invention. In particular, any combination of two or more of the claims of the claims is included in the present invention.

(A better form of implementing the invention)

[First Embodiment] A bevel ball bearing according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4 . As shown in FIG. 1 , the bevel ball bearing 11 has: an inner ring 12 ; an outer ring 13 ; a plurality of balls 14 ; and a holder 15 . A plurality of balls 14 are inserted between the raceway surfaces 12 a and 13 a of the inner ring 12 and the outer ring 13 . The balls 14 are made of steel balls or ceramic materials. The holder 15 has a cylindrical shape, and holds many balls 14 in the cavities Pt provided at a plurality of places in the circumferential direction. In this angular ball bearing 11, a general ball diameter and ball number corresponding to main dimensions (inner diameter, outer diameter, and width) are applied.

The front side end surface 13c of the outer ring 13 is connected to the raceway surface 13a via the front side inner peripheral surface 13b. The front-side inner peripheral surface 13b is a push-out surface inclined radially inward from the front-side end surface 13c as it goes toward the raceway surface 13a, and is a counterbore. Between the raceway surface 13a and the end surface 13d on the back side of the outer ring 13, a back side inner peripheral surface 13e for guiding the holder 15 is formed. The back side inner peripheral surface 13e is located radially inward of the front side inner peripheral surface 13b. The front side end surface 12c of the inner ring 12 is connected to the raceway surface 12a via the front side outer peripheral surface 12b. Between the raceway surface 12a and the end surface 12d on the back side of the inner ring 12, a back side outer peripheral surface 12e is formed. The back side outer peripheral surface 12e is located radially outward from the front side outer peripheral surface 12b. The end surfaces 12c and 13c on the front side of the inner ring 12 and the outer ring 13 indicate the end surfaces on the side not supporting the axial load, and the end surfaces 12d and 13d on the back side of the inner ring 12 and the outer ring 13 indicate the end surfaces on the side supporting the axial load. . The back side outer peripheral surface 12e of the inner ring 12, that is, the peripheral surface facing the front side inner peripheral surface 13b of the outer ring 13 in the radial direction, is formed to be radially outer than the front side outer peripheral surface 12b of the inner ring 12. Large established size. Also, in this embodiment, the front side inner peripheral surface 13b of the outer ring 13 is defined as a push-out surface, but the front side outer peripheral surface 12b of the inner ring 12 may also be configured as a push-out surface, or both may be formed as a push-out surface. Push and pull the surface to form.

(About Holder 15) The holder 15 is a holder guide type in which the outer ring is guided by the inner peripheral surface 13e on the back side of the outer ring 13, and is formed in a cylindrical shape. The outer peripheral surface of the cylindrical holder 15 serves as an outer ring guide surface, which can improve the stability of the bearing when it rotates. Each cavity Pt of the holder 15 is formed in a circular hole shape along the circumferential direction. The holder 15 is made of resin materials such as aliphatic polyamide resin (nylon), aromatic polyamide resin, polyetheretherketone resin (abbreviated: PEEK material), phenolic resin, etc. reinforced by glass fiber and carbon fiber. constituted.

This holder 15 has the following configurations 1, 2, 3 and 4.

(Composition 1: (HD-P.C.D.) > (P.C.D.-Hd)) As shown in Figure 1, the following relationship is satisfied: the value obtained by subtracting the diameter P.C.D. value.

(Composition 2: HD=D1－Sr and P.C.D.－0.35Da≦Hd≦P.C.D.－0.25Da) The outer diameter HD of the holder 15 is the diameter of the outer peripheral surface of the cylindrical shape, and is a value obtained by subtracting the radial gap Sr of the holder from the inner diameter D1 of the outer ring. The outer ring inner diameter D1 is the inner diameter of the back side inner peripheral surface 13 e of the outer ring 13 . The retainer radial clearance Sr is appropriately determined in consideration of, for example, dimensional tolerances and radial clearances of the respective bearing components.

The inner diameter Hd of the holder 15 is the diameter of the inner peripheral surface of the cylinder, which is determined as the value obtained by subtracting 0.25 to 0.35 times the diameter Da of the balls 14 from the distance circle diameter P.C.D. between the balls 14. Therefore, the contact ellipse Ce ( FIG. 3 ) generated by the revolution of the holder 15 and the contact between the ball 14 and the holder 15 does not come into contact with the inner diameter side edge 15 a of the pocket Pt of the holder 15 . Table 1 shows the application of 13/32 inch (10.31875mm) beads in the beveled ball bearing of the appellation number 7014 (inner diameter 70mm x outer diameter 110mm, width 20mm), and changing the inner diameter Hd of the holder and the wall of the holder An example of a thick T.

[Table 1] T Da×0.35 Da×0.40 Da×0.45 Da×0.50 HD PCD-Da×0.20 x x x x PCD-Da×0.25 x ○ ○ x PCD-Da×0.30 x ○ ○ x PCD-Da×0.35 x ○ ○ x PCD-Da×0.40 x x ○ x

In Table 1, the strength and load resistance of the holder are sufficient for the ring compression load described later, and the holder is established as an outer ring guide holder is indicated by "○", and the others are indicated by "×". . For example, when the inner diameter Hd of the holder is P.C.D.-Da×0.20 or less, as shown in FIG. 3 , the contact ellipse Ce contacts the inner diameter side edge 15a of the cavity Pt of the holder 15 . When the inner diameter Hd of the holder is more than P.C.D.-Da×0.40, in relation to the wall thickness of the holder, sometimes the inner diameter side of the holder contacts the inner ring guide of the inner ring, and the outer ring guide is not established, or the holding When the gap between the inner diameter side of the holder and the outer diameter side of the inner ring becomes relatively narrow, the outer ring may not be guided or be close to it in consideration of the wear of the outer diameter part of the holder when the bearing is used.

(Composition 3: 0.40Da≦T≦0.45Da) As shown in FIG. 2 , the wall thickness T of the holder 15 is set to be 0.40~0.45 times the diameter Da of the ball 14 . For example, when the wall thickness T of the holder is Da×0.35 or less, the strength and load resistance of the holder may not be sufficient. When the wall thickness T of the holder is above Da×0.50, it is impossible to form a holder. This is because the desired dimensions required for the shoulders of the inner ring and the shoulders of the outer ring limit the radial area of the retainer. Therefore, in Table 1, the case of Da×0.35 and the case of Da×0.5 are “×” for the wall thickness T of the holder.

(Composition 4: 1.6Da≦HB≦2.0Da) The axial width HB of the retainer 15 (the axial direction is common to the bevel ball bearing 11, the inner ring 12, the outer ring 13 and the retainer 15) is not extended from both ends of the bevel ball bearing 11 in the axial direction. The out range is set as 1.6~2.0 times of the diameter Da of the ball 14. In the outer ring guide holder, there is a limit to enlarging the holder on the inner diameter side in order to improve the strength and load resistance of the holder. Therefore, the retainer 15 is enlarged by maximizing the use of the axial area within the range that does not protrude from both axial ends of the inner ring 12 and the outer ring 13 . Further, extending the holder 15 in the axial direction widens the sliding contact portion between the rear inner peripheral surface 13e of the outer ring 13 and the outer peripheral surface of the holder, thereby increasing the stability of the bearing during rotation.

The retainer 15 of the bevel ball bearing 11 of the present embodiment shown in FIG. 4 is compared with the retainer 51 ( FIG. 11 ) of a conventional bevel ball bearing 50 with the same bearing size. The diameter and number of balls used in the bevel ball bearings 11, 50 of Fig. 4 and Fig. 11 are determined in response to the main dimensions of the bearings 11, 50, and are the same in the two bearings 11, 50. Also, the conventional bevel ball bearing 50 shown in FIG. 11 is an outer ring guide holder, but the wall thickness of the holder is less than 0.40 times the diameter Da of the ball 52 . Furthermore, although the axial width HBa of the conventional retainer 51 is within the range that does not protrude from both axial ends of the beveled ball bearing 50, it is less than 1.6 times the diameter Da of the ball 52.

In this case, under the same load condition, in the conventional holder 50 (FIG. 11), the contact ellipse between the ball 52 and the holder 51 touches the inner diameter side edge of the cavity Pt. In the holder 15, the contact ellipse does not come into contact with the inner diameter side edge portion 15a of the cavity Pt. In addition, compared to the conventional holder 51 ( FIG. 11 ), the holder 15 of FIG. 4 increases the cross-sectional area of the thinnest part of the holder 15, and it can be confirmed that the force of the ball 14 pushing the holder 15 is divided by The resulting value of this area adds a corresponding component to the compression stiffness of the ring, and to the fatigue limit load of the holder 15 . Therefore, it can be confirmed that the holder 15 of FIG. 4 has sufficient strength compared to the conventional holder 51 ( FIG. 11 ). The compression rigidity of the aforementioned ring refers to the axial compressive stress of the cylinder (the yield strength of the cylinder).

(Effect) According to the angled ball bearing 11 described above, in the outer ring guide holder whose outer diameter HD of the holder 15 is set as the difference between the inner diameter D1 of the outer ring and the radial clearance Sr of the holder, the inner diameter of the holder 15 is Hd is defined as the value obtained by subtracting 0.25 to 0.35 times the diameter Da of the balls 14 from the distance circle diameter P.C.D. between the balls 14, so that the radial dimension from P.C.D. out a sufficient distance. Therefore, the contact ellipse generated by the revolution of the holder 15 and the contact between the ball 14 and the holder 15 does not come into contact with the inner diameter side edge portion 15 a of the cavity of the holder 15 .

In addition, the wall thickness T of the holder 15 is set to be 0.40 to 0.45 times the diameter Da of the ball 14 . Thereby, it is possible to have sufficient retainer strength against the centrifugal force generated under high-load conditions during high-speed operation or the load caused by the hysteresis of the balls 14 . Therefore, in the angular ball bearing 11 to which the outer ring guides the holder, the strength of the holder 15 can be improved while maintaining the size and basic performance of the bearing.

[About other embodiments] In the following description, parts corresponding to matters previously described in each embodiment are denoted by the same reference numerals, and repeated descriptions are omitted. When only a part of the configuration is described, the other parts of the configuration are assumed to be the same as those previously described unless otherwise specified. The same composition exerts the same function and effect. Not only the combination of the parts specifically described in each embodiment, but also the partial combination of the embodiments can be used as long as there is no obstacle in combination.

[the second embodiment: Fig. 5 ~ Fig. 6] Alternatively, as shown in FIG. 5 , inclined portions 16 are respectively provided on both axial sides of the cavity Pt in the inner peripheral surface of the holder 15A. On the inner peripheral surface of the holder 15A, each inclined portion 16 is inclined from the axial middle portion of the portion on one axial side toward the radially outer side and extends linearly in the longitudinal section of FIG. 5 to the holder end surface.

In the longitudinal section shown in FIG. 6, the inclination angle α of the inclined portion 16 relative to the axial direction and the radial position P1 of the holder end surface in the inclined portion 16 are corresponding to the nozzle 18 of the aforementioned lubricating mechanism 17. The radial position and the inclination angle β of the nozzle 18 relative to the axial direction are determined so that the air oil flows smoothly from the lubricating mechanism 17 for air oil lubrication into the bearing space. By setting the inclination angles α and β to be in the relationship of (α-5°)<β<(α+5°), it is possible to prevent the aforementioned inclined portion 16 from being an obstacle to the flow of air and oil into the bearing space, so that the air Oil flows smoothly into the bearing space. Other configurations 1, 2, 3 and 4 are the same as those of the first embodiment.

According to this configuration, the air oil can easily flow into the bearing space from the outside of the angled ball bearing 11 along the inclined portion 16 through the nozzle 18 of the lubricating mechanism 17 , thereby improving the lubricity. Since the inclined portion 16 is an uncomplicated shape formed by a predetermined inclination angle α, it can be easily formed by a mold. In addition, the molded article molded by the mold can be easily taken out from the mold. In addition, the inclined portion 16 is not limited to the aforementioned linear shape, and may also be a curved shape or a shape in which a straight line and a curved line are smoothly linked.

[the third embodiment: Fig. 7] As shown in FIG. 7 , the retainer 15B may also have: a ball retaining extension 19 , and the inner diameter side edge of the retainer in each cavity Pt protrudes toward the inner side of the cavity. The ball retaining extension 19 has: an inclined surface 19a, which inclines greatly toward the inner side of the cavity as it goes radially inward from the vicinity of the pitch circle diameter P.C.D. between the retainers 15B. Other configurations 1, 2, 3 and 4 are the same as those of the first embodiment. When the shape of the ball holding extension 19 of the holder 15B embraces the ball 14, the strength in the circumferential direction of the holder 15B can be ensured, and the strength of the entire holder can be further improved. The ball holding extension 19 can also be easily formed by a mold like the aforementioned inclined portion 16 ( FIG. 5 ). In addition, the molded article molded by the mold can be easily taken out from the mold.

[the fourth embodiment: Fig. 8 ] Alternatively, as shown in FIG. 8 , only the place where the holder 15C holds the rolling elements in the axial direction, that is, the place where the axial rolling elements are held, may be thickened. Specifically, the retainer 15C has: a protruding part 20, protruding radially inward at the axial rolling body; inclined parts 21 on both sides of the axial direction, connected with the protruding part 20; and two circles The cylinder portion 22 is connected to each inclined portion 21 and extends to both ends in the axial direction. The inner diameter Hd1 of the aforementioned cylindrical portion 22 is determined as a value obtained by subtracting 0.25 to 0.35 times the diameter Da of the balls from the distance circle diameter P.C.D between the balls 14 .

The inner diameter Hd2 of the protruding portion 20 is set to a value obtained by adding a margin γ required for assembly to the outer diameter d1 of the inner ring 12 on the small diameter side. The aforementioned assembling necessary space γ is the necessary space (necessary clearance) required for assembling the retainer 15C and the ball 14 into the bearing space between the inner ring 12 and the outer ring 13 . The inclined portions 21 , 21 on both axial sides are inclined toward the radially outer side as they go axially outward from the axially both side edges of the protruding portion 20 . The cylindrical portions 22 , 22 extend axially outward from the axially outer edge portions of the inclined portions 21 , 21 . Also, when the outer diameter of the inner ring 12 on the large diameter side is set as d2, the relationship between the inner diameter Hd2 of the protruding portion 20 and the outer diameter d1 of the inner ring 12 on the smaller diameter side can also be set as d1<Hd2<d2 . By setting the aforementioned relationship, it is possible to maximize the strength of the holder cavity while leaving a margin necessary for assembling the holder 15C. Other configurations 1, 2, 3 and 4 are the same as those of the first embodiment. When only the rolling elements in the axial direction of the holder 15C are thickened, the strength in the circumferential direction of the holder 15C can be ensured, and the strength of the entire holder can be further enhanced.

(Application examples for electric vertical take-off and landing aircraft: Figure 9, Figure 10) The angular ball bearing can also be applied to the electric vertical take-off and landing aircraft. In recent years, as a means of mobility to replace cars, flying cars, so-called flying cars, have attracted attention. Flying vehicles are expected to be used in various situations such as intra-regional travel, inter-regional travel, sightseeing, leisure, emergency medical treatment, and disaster relief.

As far as flying vehicles are concerned, vertical take-off and landing aircraft (VTOL; Vertical Take-Off and Landing aircraft) has attracted attention. Since the vertical take-off and landing aircraft can lift vertically, it does not need a runway and is very convenient. In particular, in recent years, electric vertical take-off and landing vehicles (eVTOL) in the form of flying with batteries and electric motors have become the mainstream of development due to social demands for reducing carbon dioxide emissions.

As shown in FIG. 9 , the electric vertical take-off and landing aircraft 1 is a multi-axis aircraft, which has: a body part 2 located in the center of the body; and four drive parts 3 arranged in the front, rear, left, and right sides. The drive unit 3 is a device for generating lift and propulsion of the electric vertical take-off and landing aircraft 1 , and the electric vertical take-off and landing aircraft 1 is driven to fly by the drive unit 3 . In the electric vertical take-off and landing aircraft 1 , as long as there are a plurality of drive units 3 , it is not limited to four.

The main body portion 2 has a living space where occupants (for example, about 1 to 2 people) can board. This living space is equipped with an operating system used to determine the direction and altitude of the flight, as well as instruments that display altitude, speed, and flight position. Four arms 2 a radially extend from the main body 2 , and a drive unit 3 is provided at the tip of each arm 2 a. In FIG. 9 , the arm 2 a is integrally provided with a ring portion covering the rotation periphery of the rotor blade 4 in order to protect the rotor blade 4 . In addition, the lower part of the main body part 2 is provided with an undercarriage 2b for supporting the body during landing.

The driving unit 3 has a rotor blade 4 and a motor 5 for rotating the rotor blade 4 . A pair of rotary blades 4 are provided in the drive unit 3, and a motor 5 is sandwiched between them in the axial direction. Each rotary blade 4 has two blades extending radially outward.

Fig. 10 is a longitudinal sectional view of the motor 5 in the drive unit. The rotary blade 4 ( FIG. 9 ) is mounted on one end side (upper side in FIG. 10 ) of the rotating shaft 7 of the motor 5 , and the rotor 5 a of the motor 5 is mounted on the other end side (lower side in FIG. 10 ). The rotor 5a of the motor 5 is disposed facing the stator 5b fixed to the casing 6, and the rotor 5a is an inner rotor type that can rotate relative to the stator 5b and is a direct drive type. Also, as the motor 5, an outer rotor type brushless motor or an inner rotor type brushless motor can be used.

In FIG. 10, the motor 5 is provided with: the housing 6; the rotor 5a; the stator 5b; The casing 6 has an outer cylinder 6a and an inner cylinder 6b, and a flow passage 6c through which the refrigerant flows is provided between the outer cylinder 6a and the inner cylinder 6b. By allowing the refrigerant to flow through this flow path 6c, the temperature of the motor 5 can be prevented from rising excessively.

The angular ball bearing 11 rotatably supports the rotary shaft 7 within the housing 6 . The shape of the outer periphery of the outer ring 13 of the angular ball bearing 11 is the same shape as the fitting portion on the inner periphery of the housing, and is directly fitted to the housing 6 without interposing the bearing housing or the like. In this example, the two angled ball bearings 11 , 11 are arranged in a combination of the inner ring spacer 8 and the outer ring spacer 9 on the back side, and a preload is applied thereto.

(About control system) The main body part 2 is provided with: the control device 31 which controls many motors 5 etc.; and the battery 32 which supplies electric power to each motor 5 and the control device 31. The control device 31 has: an inverter for converting the DC power of the battery 32 into an AC voltage; and a control unit for controlling the output of the inverter by means of PWM control or the like in response to a torque command generated by the operating system. The above-mentioned control part outputs the instruction of changing the rotational speed to the electric motor 5 to adjust the lift from the difference between the current posture and the target posture, so as to change the rotational speed of the electric motor 5 and the rotor 4 ( FIG. 9 ). The rotation speed adjustment of the electric motors 5 is implemented simultaneously for most electric motors 5, and thereby determines the posture of the body.

In FIG. 10, the rotation axis of the motor 5 and the rotation axis of the rotor blade 4 (FIG. 9) are set as the same rotation axis, but it is also possible to connect the rotation shaft of the motor and the rotation axis of the rotor blade through a transmission mechanism. . In this case, the angled ball bearing supporting the rotating shaft in the drive unit may be an angled ball bearing supporting the rotating shaft of the motor, or an angled ball bearing supporting the rotating shaft of the rotor blade.

Angled ball bearings can also be used in frontal combinations. The angular ball bearing can also be applied to purposes other than electric vertical take-off and landing aircraft. The holder of the angular ball bearing can not only be formed by a mold, but also can be produced by machining or a 3D printing machine.

As described above, preferred embodiments have been described with reference to the drawings, but those skilled in the art should be able to easily conceive various changes and modifications within the scope of self-explanation after reading this specification. Therefore, such changes and amendments should be interpreted as within the scope of the present invention determined by the appended claims.

1: Electric vertical take-off and landing aircraft 2: Main body 2a: arm 2b: Landing gear 3: drive unit 4: Rotary wing 5: Motor 5a: rotor 5b: Stator 6: shell 6a: Outer cylinder 6b: inner cylinder 6c: Runner 7: Rotation axis 8: Inner ring spacer 9: Outer ring spacer 11: Angled ball bearing 12: inner ring 12a: Orbital surface 12b: Outer peripheral surface on the front side 12c: end face 12d: end face 12e: Outer peripheral surface on the back side 13: outer ring 13a: Orbital surface 13b: Inner peripheral surface on the front side 13c: end face 13d: end face 13e: Inner peripheral surface on the back side 14: Ball 15,15A,15B,15C: Holder 15a: inner diameter side edge 16: Inclined part 17: Lubrication mechanism 18: Nozzle 19: Ball holding extension 19a: Inclined surface 20: protruding part 21: inclined part 22: Cylindrical part 31: Control device 32: battery 50: Angled ball bearing 51: Holder 52: Ball HB: axial width HBa: axial width HD: outer diameter Hd: inner diameter Hd1: inner diameter Hd2: inner diameter Ce: contact ellipse d1: Outer diameter of small diameter side Da: diameter D1: inner diameter of outer ring Sr: radial clearance T: wall thickness P.C.D.: Pitch circle diameter Pt: Cavity α: tilt angle β: tilt angle γ: Necessary to leave blank

The present invention can be understood more clearly by referring to the description of the following preferred embodiments with reference to the attached drawings. However, the embodiments and drawings are only for illustration and description, and are not intended to determine the scope of the present invention. The scope of the present invention is determined by the appended claims. In the attached drawings, the same reference numerals in most of the drawings represent the same part. Fig. 1 is a longitudinal sectional view of a bevel ball bearing according to a first embodiment of the present invention. Fig. 2 is an enlarged longitudinal sectional view of the bevel ball bearing of Fig. 1 . Fig. 3 is a partially enlarged view of important parts of the retainer of Fig. 1 viewed from the axial direction. FIG. 4 is used to compare the holder of FIG. 1 with a conventional holder. Fig. 5 is a longitudinal sectional view of a second embodiment of an oblique ball bearing of the present invention. Fig. 6 is a longitudinal sectional view of the bearing device equipped with the bevel ball bearing and the lubricating mechanism of Fig. 5 . Fig. 7 is a longitudinal sectional view of a bevel ball bearing according to a third embodiment of the present invention. Fig. 8 is a longitudinal sectional view of a bevel ball bearing according to a fourth embodiment of the present invention. Fig. 9 is a perspective view of an electric vertical take-off and landing aircraft equipped with an oblique ball bearing of the present invention. Fig. 10 is a longitudinal sectional view of a motor including the angular ball bearing of Fig. 8 . Fig. 11 is a longitudinal sectional view of an angular ball bearing provided with a conventional retainer.

11: Angled ball bearing

12: inner ring

12a: Orbital surface

12b: Outer peripheral surface on the front side

12c: end face

12d: end face

12e: Outer peripheral surface on the back side

13: outer ring

13a: Orbital surface

13b: Inner peripheral surface on the front side

13c: end face

13d: end face

13e: Inner peripheral surface on the back side

14: Ball

15: Holder

HD: outer diameter

Hd: inner diameter

Da: diameter

D1: inner diameter of outer ring

Sr: radial clearance

P.C.D.: Pitch circle diameter

Pt: Cavity

Claims (6)

An oblique ball bearing is provided with: an inner ring; an outer ring; a plurality of balls inserted between the inner ring and the outer ring; In the cavities in multiple directions; and the holder is in the form of a holder guide guided by an outer ring, wherein, If the outer diameter of the holder is HD, the inner diameter of the holder is Hd, and the diameter of the distance circle between the balls is P.C.D., the relationship of HD-P.C.D.>P.C.D.-Hd is satisfied, And the inner diameter Hd of the holder is set as the value obtained by subtracting 0.25~0.35 times the diameter Da of the ball from the distance circle diameter P.C.D. between the balls, and the wall thickness T of the holder is set as the diameter of the ball 0.40~0.45 times of Da. Such as the oblique ball bearing of claim 1, wherein, The axial width HB of the holder is set to be 1.6~2.0 times the diameter Da of the ball within the range that does not protrude from the axial ends of the inner ring and the outer ring of the angular ball bearing . As the oblique ball bearing of claim 1 or 2, wherein, The inner peripheral surface of the holder is provided with: an inclined portion, which is inclined so as to be closer to the radial outer side as it goes axially outward. The oblique ball bearing according to any one of claims 1 to 3, wherein, The retainer has: a ball retaining protruding part, and the inner diameter side edge of the retainer in each cavity protrudes toward the inner side of the cavity. Such as the oblique ball bearing of claim 4, wherein, The holder has a protruding part protruding radially inward, the outer diameter of the small diameter side of the inner ring is set as d1, the outer diameter of the large diameter side is set as d2, and the inner diameter of the protruding part is set as When Hd2, the relationship of d1<Hd2<d2 is satisfied. For example, the oblique ball bearing of claims 1 to 5 is mounted on an electric vertical take-off and landing aircraft, and the electric vertical take-off and landing aircraft includes: a plurality of rotors; and a plurality of driving parts, which have electric motors for rotating the rotors; And the electric vertical take-off and landing aircraft flies by the rotation of the rotary wing, and the angular ball bearing supports the rotating shaft in the driving part to be rotatable.

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