Ball launcher and rotor

Abstract

The object of the present invention is to provide a technology that can suppress wear of the balls by the rotors in a ball launching device that launches balls using the rotational force of multiple rotors. [Solution] In the ball launching device, at least one of the multiple rotors has a rotor body supported by the main body of the ball launching device via a rotating shaft member, and an outer peripheral member attached to the rotor body so as to cover the outer peripheral surface of the rotor body and formed of an elastic material. In at least one rotor, the outer peripheral member is attached to the rotor body such that the outer peripheral portion of the outer peripheral member that covers the outer peripheral surface of the rotor body is displaceable relative to the outer peripheral surface of the rotor body.

Description

Technical Field

[0001] The present invention relates to a ball launching device.

Background Art

[0002] Conventionally, a ball launching device that sandwiches a ball by a plurality of rotors and launches the ball by the rotational force of the plurality of rotors is known (see, for example, Patent Documents 1 to 3). Here, Patent Document 1 discloses a pitching machine in which three pitching rotors are arranged in a Y shape. In the pitching machine disclosed in Patent Document 1, in the central lower rotor located below the three rotors, the rotor shaft is attached to the rotor support structure via a cushion device. The cushion device is configured to be vertically movable with respect to the rotor support structure.

[0003] Also conventionally, a configuration in which the outer peripheral surface of a rotor in a ball launching device is covered with an elastic body is known (see, for example, Patent Document 4). Here, Patent Document 4 discloses a rotor in which the outer peripheral surface of a metal wheel is covered with urethane rubber. In the rotor disclosed in Patent Document 4, the urethane rubber ring is configured to be separable from the metal wheel. And the urethane rubber ring is pressed by a ring-shaped urethane rubber retainer in a state of being attached to the metal wheel.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

[0005] In a ball launcher that uses the rotational force of multiple rotors to launch a ball, the ball is fed between multiple rotors that are rotating at high speed. The ball, trapped between the rotors, is then launched from between them at a speed corresponding to the rotational speed of the rotors. At this time, until the speed at which the ball moves between the rotors reaches a speed corresponding to the rotational speed of the rotors, the rotors slip on the surface of the ball. This can cause the surface of the ball to rub against the rotors, potentially leading to wear and tear on the ball.

[0006] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a technology that can suppress wear of the balls by the rotors in a ball launching device that launches balls by the rotational force of multiple rotors. [Means for solving the problem]

[0007] A ball launching device according to a first aspect of the present invention is a ball launching device that sandwiches a ball between a plurality of rotors and launches the ball by the rotational force of the plurality of rotors, wherein at least one of the plurality of rotors has a rotor body supported by the body of the ball launching device via a rotating shaft member, and an outer peripheral member attached to the rotor body so as to cover the outer peripheral surface of the rotor body and formed of an elastic material, wherein in the at least one rotor, the outer peripheral member of the rotor body The outer peripheral member is attached to the rotor body such that the outer peripheral portion, which covers the circumferential surface, is displaceable relative to the outer peripheral surface of the rotor body.

[0008] In the ball launching device according to the first aspect of the present invention, each of the multiple rotors is supported by the main body of the ball launching device via a rotating shaft member. A ball is then sandwiched between the multiple rotors, which rotate at high speed around the axis of rotation of the rotating shaft member, and the ball is launched by the rotational force of the multiple rotors.

[0009] Furthermore, at least one of the multiple rotors has a rotor body and an outer peripheral member. The rotor body is supported by the body of the ball launcher via a rotating shaft member. The outer peripheral member is made of an elastic material. The outer peripheral member is attached to the rotor body so as to cover the outer peripheral surface of the rotor body. Therefore, in at least one rotor, the outer peripheral surface of the outer peripheral portion of the outer peripheral member that covers the outer peripheral surface of the rotor body comes into contact with the ball. In other words, friction occurs between the outer peripheral surface of the outer peripheral portion of the outer peripheral member and the ball.

[0010] Here, the outer peripheral member is formed of an elastic material. The outer peripheral member is attached to the rotor body, but the outer circumference of the outer peripheral member is displaceable relative to the outer surface of the rotor body. Therefore, when the rotor is rotating at high speed, if a ball comes into contact with the outer surface of the outer peripheral member and friction occurs between them, the outer circumference of the outer peripheral member will temporarily displace relative to the outer surface of the rotor body in the opposite direction to the rotor's rotation. When the outer circumference of the outer peripheral member displaces relative to the outer surface of the rotor body in the opposite direction to the rotor's rotation while in contact with the ball, friction on the surface of the ball by the outer peripheral member becomes less likely.

[0011] Furthermore, even if the outer circumference of the outer peripheral member is displaced relative to the outer circumference of the rotor body, the rotational force of the rotor increases the ball's speed while the displaced outer circumference of the outer peripheral member and the ball remain in contact. Subsequently, the ball is launched from the ball launcher at a speed corresponding to the rotor's rotational speed. Also, when the ball is launched from the ball launcher, the ball separates from the outer circumference of the outer peripheral member in at least one rotor, and the displacement of the outer circumference of the outer peripheral member relative to the outer circumference of the rotor body is eliminated.

[0012] As described above, according to the ball launching device of the first aspect of the present invention, in at least one rotor, friction of the ball's surface by the rotor or the outer peripheral member of the rotor, which occurs when the ball is caught between multiple rotors rotating at high speed, can be suppressed. Therefore, wear of the ball by the rotor can be suppressed.

[0013] In a ball launching device according to a first aspect of the present invention, when a ball is caught between the rotating plurality of rotors in at least one rotor, the outer circumference of the outer peripheral member may be displaced in the opposite direction to the rotation direction of the at least one rotor relative to the outer peripheral surface of the rotor body, so that a part of the outer circumference is separated from the outer peripheral surface of the rotor body. This allows the outer circumference of the outer peripheral member to be displaced more significantly relative to the outer peripheral surface of the rotor body when friction occurs between the ball caught between the plurality of rotors and the outer circumference of the outer peripheral member. Therefore, friction on the surface of the ball by the outer peripheral member can be further suppressed.

[0014] In the ball launching device according to the first aspect of the present invention, in at least one rotor, a portion of the outer peripheral member other than the outer peripheral portion, or a portion of the outer peripheral portion of the outer peripheral member other than the contact portion where the outer peripheral surface contacts the ball, may be fixed to the rotor body. In this way, in at least one rotor, by fixing a predetermined portion of the outer peripheral member to the rotor body, the rotational force of the rotor body is transmitted via the outer peripheral member. This allows for efficient power transfer to the ball. On the other hand, if the fixing position of the outer peripheral member to the rotor body is a part other than the outer peripheral portion, the outer peripheral portion can be displaced relative to the outer peripheral surface of the rotor body. Also, if the fixing position of the outer peripheral member to the rotor body is a part other than the contact portion of the outer peripheral portion of the outer peripheral member, the contact portion of the outer peripheral portion of the outer peripheral member can be displaced relative to the outer peripheral surface of the rotor body.

[0015] Here, if the outer peripheral member extends to the vicinity of the outer circumference of both sides of the rotor body, the portion of the outer peripheral member other than the outer circumference may be a portion that covers the vicinity of the outer circumference of both sides of the rotor body. Also, if the central portion of the outer peripheral member in the direction of the rotation axis of at least one rotor is the contact portion, the portion of the outer peripheral member other than the contact portion may be a lateral portion of the outer peripheral member located on both sides of the contact portion in the direction of the rotation axis of at least one rotor.

[0016] In the ball launching device according to the first aspect of the present invention, a lubricant may be sandwiched between the outer surface of the rotor body and the inner surface of the outer portion of the outer peripheral member in at least one rotor. This makes it easier for the outer peripheral member to displace relative to the rotor body in at least one rotor when friction occurs between the ball sandwiched between multiple rotors and the outer peripheral member. Therefore, friction on the surface of the ball by the outer peripheral member can be further suppressed.

[0017] In the ball launching device according to the first aspect of the present invention, in at least one rotor, the cross-sectional shape of the outer surface of the rotor body and the outer circumference of the outer peripheral member in the direction of the rotation axis of the at least one rotor may be V-shaped or concave. According to this, in at least one rotor, the diameter of the central portion of the outer peripheral member in the direction of the rotation axis of the rotor is smaller than the diameter of the lateral portion in the direction of the rotation axis of the rotor. As a result, the tension of the central portion of the outer peripheral member is weaker compared to the case where the diameter of the central portion of the outer peripheral member in the direction of the rotation axis of the rotor is equal to the diameter of the lateral portion in the direction of the rotation axis of the rotor. This makes it easier for the outer peripheral member to displace relative to the outer surface of the rotor body in at least one rotor when friction occurs between the ball sandwiched between multiple rotors and the outer peripheral member. Therefore, friction on the surface of the ball by the outer peripheral member can be further suppressed.

[0018] Further, the rotor according to the second aspect of the present invention is a rotor of a ball launcher that sandwiches a ball by a plurality of rotors and launches the ball by the rotational force of the plurality of rotors, and includes a rotor body supported by a main body of the ball launcher via a rotary shaft member, and an outer peripheral member formed of an elastic body and attached to the rotor body so as to cover an outer peripheral surface of the rotor body. The outer peripheral member is attached to the rotor body such that an outer peripheral portion, which is a portion of the outer peripheral member covering the outer peripheral surface of the rotor body, is displaceable with respect to the outer peripheral surface of the rotor body.

Advantages of the Invention

[0019] According to the present invention, in a ball launcher that launches a ball by the rotational force of a plurality of rotors, wear of the ball by the rotor can be suppressed.

Brief Description of the Drawings

[0020] [Figure 1] FIG. 1 is a front view of the ball launcher. [Figure 2] FIG. 2 is a side view of the ball launcher. [Figure 3] FIG. 3 is a side view of the rotor support portion. [Figure 4] FIG. 4 is a diagram for explaining the configuration of the attachment portion of the rotor in the rotor support portion. [Figure 5] FIG. 5 is a diagram for explaining the configuration of the rotor. FIG. 5(a) is a side view of the rotor when viewed from the right side. FIG. 5(b) is a cross-sectional view of the rotor in the rotational axis direction. [Figure 6] FIG. 6 is a diagram for explaining the configuration of the attachment portion of the outer peripheral member to the rotor body. [Figure 7] FIG. 7 is a diagram showing the state of the rotor and the ball when the ball is launched by the ball launcher. [Figure 8] FIG. 8 is a diagram for explaining the configuration of the rotor according to the first modification. [Figure 9] Figure 9 is a diagram illustrating the configuration of the rotor according to the second modified example. [Figure 10] Figure 10 shows an example of scratches on the surface of a ball caused by friction from the rotor. [Modes for carrying out the invention]

[0021] The following describes specific embodiments of the present invention with reference to the drawings. Unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments are not intended to limit the technical scope of the present invention to those specific components.

[0022] <Embodiment> [Overall structure] The schematic configuration of the ball launcher according to this embodiment will be described based on Figures 1 and 2. Figures 1 and 2 are diagrams showing an example of the schematic configuration of the ball launcher according to this embodiment. Figure 1 is a front view of the ball launcher 1. In Figure 1, the direction perpendicular to the vertical direction is the left-right direction. In the following description, the left side of Figure 1 will be referred to as the left direction, and the right side of Figure 1 will be referred to as the right direction. Figure 2 is a side view of the ball launcher 1 when viewed from the right side. In the following description, the left side of Figure 2 will be referred to as the front, and the right side of Figure 2 will be referred to as the rear. Also, in Figures 1 and 2, circle V represents the ball that will be launched by the ball launcher 1.

[0023] The ball launcher 1 comprises a main body 2 and two rotors 3. Each rotor 3 has a substantially cylindrical shape with its rotation axis as its central axis. The two rotors 3 are mounted on the main body 2 such that their rotation axes (central axes) are substantially parallel to each other. The two rotors 3 are also arranged vertically with a predetermined distance between their outer surfaces. In the ball launcher 1, the ball V to be launched is fed from the rear between the two rapidly rotating rotors 3. The ball V is then sandwiched between the two rotors 3, and the rotational force of the two rotors 3 launches the ball V forward.

[0024] Here, as shown in Figures 1 and 2, the distance between the outer surfaces of the two rotors 3 of the ball launcher 1 is smaller than the outer diameter of the ball V. Therefore, the ball V is compressed and sandwiched between the two rotors 3. For example, the distance T between the outer surfaces of the two rotors 3 (the distance between the narrowest part between the outer surfaces of the two rotors 3) may be set according to the following formula. T = K × D1 D1: Outer diameter of ball V K: Coefficient (0.5~0.99)

[0025] The main body 2 of the ball launcher 1 comprises a stand 21, a rotor support section 22, and a rotor cover 23. The upper end of the stand 21 is provided with a mounting section 211 for attaching the rotor support section 22. The rotor support section 22 comprises a support shaft 221, a support plate 222, It also has a support frame 223. A rotor cover 23 is provided for each of the two rotors 3.

[0026] The support shaft 221 of the rotor support section 22 is attached to the mounting section 211 of the frame 21. The support shaft 221 is attached to the mounting section 211 with the left side portion of the support shaft 221, which extends in the left-right direction, inserted through it. In the rotor support section 22, the right end of the support shaft 221 is connected to the left side surface of the support plate 222, and the right side surface of the support plate 222 is connected to the support frame 223.

[0027] The support frame 223 of the rotor support section 22 is a frame assembled in a roughly rectangular shape with the vertical direction as its longitudinal direction. Rotors 3 are attached to the upper and lower ends of the support frame 223, respectively. The two rotors 3 are located on the right side of the support frame 223. Two motors 4 for rotating each rotor 3 are attached to the left side of the support frame 223. In the following description, when distinguishing between the two rotors 3, the rotor 3 attached to the upper end of the support frame 223 will be referred to as the first rotor 3a, and the rotor 3 attached to the lower end of the support frame 223 will be referred to as the second rotor 3b.

[0028] A rotor cover 23 is attached to the support frame 223 to cover each rotor 3. A rotor cover 23 is provided at the upper end of the support frame 223 to cover the portion of the first rotor 3a excluding the lower portion. A rotor cover 23 is provided at the lower end of the support frame 223 to cover the portion of the second rotor 3b excluding the upper portion.

[0029] In the ball launching device 1, the rotational speed of each rotor 3 can be adjusted by controlling the output of each motor 4 with a control device (not shown). By adjusting the rotational speed of each rotor 3, the launching speed of the ball V and the rotational state of the ball V can be changed. The rotational speeds of the two rotors 3 may also be controlled independently.

[0030] Furthermore, the ball launcher 1 may be provided with a ball guide frame for feeding the ball V between the two rotors 3. Also, the rotor support section 22 may be mounted to the base 21 in a way that allows for variable height and angle adjustments. By changing the height and angle of the rotor support section 22, the height of the launch position and the launch angle of the ball V can be changed.

[0031] Furthermore, the ball launcher 1 may also be configured to include three or more rotors. In this case, the three or more rotors are arranged at a predetermined distance from each other, and the ball V is sandwiched between the three or more rotors.

[0032] The ball launching device 1 can be used, for example, as a pitching machine for baseball, a ball-dispensing machine for tennis, a serving machine for volleyball, or a soccer machine. The shape of the ball launched by the ball launching device 1 is not limited to a spherical shape with a circular cross-section, like ball V. For example, a ball with an elliptical cross-section may also be used as the target of launching.

[0033] [Configuration of the rotor support section] Next, the more detailed configuration of the rotor support section 22 will be described based on Figures 3 and 4. Figure 3 is a side view of the rotor support section 22 when viewed from the right side. Figure 4 is a diagram illustrating the configuration of the mounting portion of the rotor 3 in the rotor support section 22. In Figure 4, the mounting portion of the rotor 3 in the rotor support section 22 is shown. The area near the attachment point is shown in Figure 3 as a cross-sectional view of the cross section indicated by AA. Note that in Figures 3 and 4, the rotor cover 23 is removed for convenience. Also in Figures 3 and 4, circle V represents the ball to be launched by the ball launcher 1.

[0034] A motor 4 is attached to the upper and lower ends of the support frame 223 from the left side. A rotor mounting portion 225 is provided at the upper and lower ends of the support frame 223, opposite the motor 4. A rotor 3 is attached to each rotor mounting portion 225. The rotor 3 is attached to the rotor mounting portion 225 via a rotating shaft member 33. One end 331 of the rotating shaft member 33 is connected to the rotor body 31 of the rotor 3. The rotor 3 rotates around the central axis of the rotating shaft member 33 as its axis of rotation. The detailed configuration of the rotor 3 will be described later.

[0035] The other end 332 of the rotating shaft member 33 of the rotor 3 is connected to the drive shaft 41 of the motor 4, which is located opposite, via a coupling portion 42. This allows the driving force of the motor 4 to be transmitted from the drive shaft 41 to the rotating shaft member 33 via the coupling portion 42. Furthermore, the rotating shaft member 33 is rotatably supported on the rotor mounting portion 225 via a bearing portion 226. Thus, the rotor body 31 of the rotor 3 is rotatably supported on the rotor support portion 22 via the rotating shaft member 33.

[0036] [Rotor configuration] Next, the more detailed configuration of the rotor 3 will be described based on Figures 5 and 6. Figure 5 is a diagram illustrating the configuration of the rotor 3. Figure 5(a) is a side view of the rotor 3 as seen from the right side. Figure 5(b) is a cross-sectional view of the rotor 3 in the direction of the rotation axis. Figure 5(b) is a cross-sectional view of the cross section indicated by BB in Figure 5(a). Figure 6 is a diagram illustrating the configuration of the attachment portion of the outer peripheral member 32 to the rotor body 31 in the rotor 3. In Figure 6, the attachment portion of the outer peripheral member 32 to the rotor body 31 in the rotor 3 is shown as a cross-sectional view in the direction of the rotation axis.

[0037] The rotor 3 comprises a rotor body 31 and an outer peripheral member 32. The rotor body 31 is a substantially cylindrical member. The rotor body 31 may be made of a metal such as aluminum or iron. Alternatively, the rotor body 31 may be made of resin to reduce weight. The outer peripheral member 32 is a member that covers the outer peripheral surface 31A of the rotor body 31. The outer peripheral member 32 is cylindrical and made of an elastic material.

[0038] The outer periphery member 32 may be made of rubber such as natural rubber, nitrile rubber, urethane rubber, silicone rubber, fluororubber, isoprene rubber, styrene rubber, or butadiene rubber. Furthermore, if the outer periphery member 32 is made of cylindrical rubber, its thickness may be 0.5 to 3.0 mm. More preferably, the thickness of the cylindrical rubber may be 1.0 to 2.0 mm. Also, if the outer periphery member 32 is made of cylindrical natural rubber, the durometer hardness (Type A) of the natural rubber may be 10 to 50. More preferably, the durometer hardness (Type A) of the natural rubber may be 20 to 40. The outer periphery member 32 may also be configured such that multiple holes are formed in at least a portion of the cylindrical wall surface. Furthermore, the outer periphery member 32 may be configured such that the cylindrical wall surface is formed in a mesh pattern. When the cylindrical wall surface of the outer periphery member 32 is formed in a mesh pattern, a material other than rubber may be used, and the outer periphery member 32 may be structurally elastic.

[0039] The outer peripheral member 32 is attached to the rotor body 31 so as to cover the outer peripheral surface 31A of the rotor body 31. Therefore, in the ball launching device 1, the outer peripheral surface 32A of the outer peripheral portion 321 of the outer peripheral member 32 comes into contact with the ball V sandwiched between the two rotors 3.

[0040] More specifically, the rotor body 31, as shown in Figure 5(b), has a cylindrical member 311, a first side member 312, and a second side member 313. The cylindrical member 311 is a cylindrical member that forms the outer circumferential surface 31A of the rotor body 31. In other words, the outer circumferential wall surface of the cylindrical member 311 forms the outer circumferential surface 31A of the rotor body 31. The first side member 312 is attached to the right end of the cylindrical member 311, and the second side member 313 is attached to the left end of the cylindrical member 311. The first side member 312 and the second side member 313 are screwed to each end of the cylindrical member 311 by a plurality of screws 314 arranged circumferentially.

[0041] Here, the first side member 312 has a disc shape and is attached to the right end of the cylindrical member 311 so as to cover the entire right-side opening of the cylindrical member 311. In addition, a mounting hole 312A is formed in the center of the first side member 312 for attaching one end of the rotating shaft member 33 of the rotor 3. One end of the rotating shaft member 33 is attached to the mounting hole 312A of the first side member 312 from the left side (i.e., the inside side of the rotor body 31).

[0042] On the other hand, the second side member 313 has a ring shape. Therefore, the second side member 313 is attached to the left end of the cylindrical member 311 so as to cover only the portion near the inner circumferential surface of the cylindrical member 311 at the left opening of the cylindrical member 311. As a result, an opening 31B is formed on the left side of the rotor body 31. Then, as shown in Figure 4, when the rotor 3 is attached to the rotor mounting portion 225 of the rotor support portion 22, the rotor mounting portion 225 protrudes from the opening 31B of the rotor body 31 into the internal space of the rotor 3. Then, within the internal space of the rotor 3, the rotating shaft member 33 is supported by the bearing portion 226.

[0043] Furthermore, in the rotor 3, the width of the outer peripheral member 32 (the width in the rotation axis direction of the rotor 3) is greater than the width of the rotor body 31. Therefore, in the outer peripheral member 32, the ends 322 located on both sides of the outer peripheral portion 321, which covers the outer peripheral surface 31A of the rotor body 31, extend to the vicinity of the outer peripheral on both sides of the rotor body 31. Then, on both sides of the rotor body 31, the ends 322 on both sides of the outer peripheral member 32 are fixed to the rotor body 31 using fixing ring members 34 and 35.

[0044] Here, we will explain in detail how the outer peripheral member 32 is attached to the rotor body 31 in the rotor 3. Figure 6 shows the attachment portion of the outer peripheral member 32 on the right side (first side member 312 side) of the rotor 3.

[0045] In the first side member 312 of the rotor body 31, a stepped portion 3121 is formed around the entire circumference near the outer circumference connected to the cylindrical member 311. The stepped portion 3121 is formed by the portion of the first side member 312 near the outer circumference being recessed inward towards the rotor 3 so as to conform to the inner surface of the cylindrical member 311. Furthermore, as shown in Figure 6, a portion of the wall surface of the stepped portion 3121 is tapered. Hereinafter, the tapered portion of the wall surface of the stepped portion 3121 will be referred to as the tapered portion 3121a. The wall surface of the tapered portion 3121a of the stepped portion 3121 is inclined in a direction such that the diameter of the inner circumference circle formed by the wall surface gradually decreases from the outside to the inside of the rotor 3 (from the right side to the left side in Figure 6).

[0046] A fixing ring member 34 is fitted into the stepped portion 3121 of the first side member 312, sandwiching the right end 322 of the outer peripheral member 32. More specifically, as shown in Figure 6, the outer peripheral surface 341 of the fixing ring member 34 is tapered, and its inclination corresponds to the inclination of the tapered portion 3121a of the stepped portion 3121 of the first side member 312. In other words, the outer peripheral surface 341 of the fixing ring member 34 is such that the outer diameter of the fixing ring member 34 is such that the rotor 3 The outer surface is inclined in a direction that gradually decreases from the outside to the inside (from the right to the left in Figure 6). The right end 322 of the outer peripheral member 32 is sandwiched between the tapered portion 3121a of the stepped portion 3121 of the first side surface member 312 and the outer peripheral surface 341 of the fixing ring member 34, and the fixing ring member 34 is screwed to the first side surface member 312 by screws 36. As shown in Figure 5(a), the fixing ring member 34 is screwed to the first side surface member 312 by multiple screws 36 arranged on the circumference.

[0047] Furthermore, in the second side member 313 of the rotor body 31, similar to the first side member 312, a stepped portion 3131 is formed around the entire circumference of the portion near the outer circumference connected to the cylindrical member 311. The stepped portion 3131 is formed by the portion near the outer circumference of the second side member 313 being recessed inward towards the rotor 3 so as to conform to the inner circumferential surface of the cylindrical member 311. In addition, the stepped portion 3131 of the second side member 313 also has a tapered portion similar to the tapered portion 3121a of the stepped portion 3121 of the first side member 312.

[0048] Furthermore, a fixing ring member 35 is fitted into the stepped portion 3131 of the second side member 313, sandwiching the left end 322 of the outer peripheral member 32. Similar to the fixing ring member 34, the outer peripheral surface of the fixing ring member 35 is tapered, and its inclination corresponds to the inclination of the tapered portion of the stepped portion 3131 of the second side member 313. With the left end 322 of the outer peripheral member 32 sandwiched between the tapered portion of the stepped portion 3131 of the second side member 313 and the outer peripheral surface of the fixing ring member 35, the fixing ring member 35 is screwed to the second side member 313 by screws 37. The fixing ring member 35 is screwed to the second side member 313 by multiple screws 37 arranged on its circumference.

[0049] As described above, in the rotor 3, both ends 322 of the outer peripheral member 32 are fixed to the rotor body 31. On the other hand, as shown in Figure 5(b), the cross-sectional shape of the outer peripheral surface 31A of the rotor body 31 in the direction of the rotation axis of the rotor 3 is substantially straight. The inner peripheral surface of the outer peripheral portion 321 of the outer peripheral member 32 is in contact with the outer peripheral surface 31A of the rotor body 31. However, the outer peripheral portion 321 of the outer peripheral member 32 is not fixed to the rotor body 31. Therefore, the outer peripheral portion 321 of the outer peripheral member 32 is displaceable relative to the outer peripheral surface 31A of the rotor body 31. In other words, in the ball launching device 1 according to this embodiment, the outer peripheral member 32 is attached to the rotor body 31 in such a way that the outer peripheral portion 321 of the outer peripheral member 32, which is formed of an elastic material, is displaceable relative to the outer peripheral surface 31A of the rotor body 31. Furthermore, the rotor 3 is configured such that the outer peripheral portion 321 of the outer peripheral member 32 can be displaced relative to the outer peripheral surface 31A of the rotor body 31, thereby allowing the outer peripheral portion 321 of the outer peripheral member 32 to move away from the outer peripheral surface 31A of the rotor body 31.

[0050] Furthermore, in the rotor 3, the method of fixing the ends 322 on both sides of the outer peripheral member 32 to the rotor body 31 is not limited to the method using the fixing ring members 34 and 35 as described above. For example, the ends 322 on both sides of the outer peripheral member 32 may be directly screwed to the first side member 312 and the second side member 313 of the rotor body 31, respectively.

[0051] [Effects / Effects] In the ball launching device 1, when the rotors 3 are rotating without a ball V sandwiched between them (i.e., when the ball V is not in contact with the outer surface 32A of the outer peripheral member 32 of the rotor 3), the rotor body 31 and the outer peripheral member 32 rotate together as a single unit. In other words, the outer peripheral portion 321 of the outer peripheral member 32 and the rotor body 31 rotate at the same rotational speed. When a ball V is fed between the two rotors 3 rotating at high speed, the outer surface 32A of the outer peripheral portion 321 of the outer peripheral member 32 of the rotor 3 comes into contact with the ball V. As a result, friction is generated between the outer surface 32A of the outer peripheral portion 321 of the outer peripheral member 32 of the rotor 3 and the ball V.

[0052] Here, the coefficient of friction between the outer surface 32A of the outer peripheral member 32 of the rotor 3 and the ball V is greater than the coefficient of friction between the inner surface of the outer peripheral member 32 and the outer surface 31A of the rotor body 31. Also, as described above, in the rotor 3, the outer peripheral portion 321 of the outer peripheral member 32 is displaceable relative to the outer peripheral surface 31A of the rotor body 31. Therefore, when the rotor 3 is rotating at high speed, if the ball V comes into contact with the outer peripheral surface 32A of the outer peripheral portion 321 of the outer peripheral member 32 and friction occurs between them, the outer peripheral portion 321 of the outer peripheral member 32 is temporarily displaced relative to the outer peripheral surface 31A of the rotor body 31 in the opposite direction to the rotation direction of the rotor 3.

[0053] Figure 7 shows the state of the rotor 3 and ball V when ball V is launched by the ball launcher 1. Figures 7(a) to (c) show the state of rotor 3 (first rotor 3a) and ball V when ball V is trapped between two rotors 3 rotating at high speed. In Figures 7(a) to (c), the arrows indicate the direction of rotation of rotor 3. Also, in Figure 7, time progresses in the order of (a), (b), and (c). Therefore, in Figure 7, as time progresses from (a) to (c), ball V moves from rear to front.

[0054] When a ball V is sandwiched between the two rotors 3, friction occurs between the outer surface 32A of the outer circumference 321 of the outer peripheral member 32 and the ball V, causing the rotational speed of the contact portion of the outer peripheral member 321 with the ball V to decrease. As a result, the outer peripheral member 321 of the outer peripheral member 32 is displaced relative to the outer surface 31A of the rotor body 31 in the opposite direction to the rotational direction of the rotor 3. At this time, the amount of displacement of the outer peripheral member 321 of the outer peripheral member 32 relative to the outer surface 31A of the rotor body 31 becomes larger near the contact portion of the outer peripheral member 321 with the ball V.

[0055] As the displacement of the outer circumference 321 of the outer peripheral member 32 relative to the outer peripheral surface 31A of the rotor body 31 increases, a portion of the outer circumference 321 separates from the outer peripheral surface 31A of the rotor body 31. In Figures 7(a) to (c), the area enclosed by the dashed line shows the portion where the outer circumference 321 of the outer peripheral member 32 separates from the outer peripheral surface 31A of the rotor body 31. As shown in Figures 7(a) to (c), the rear portion of the outer circumference 321 of the outer peripheral member 32 in the direction of rotation of the rotor 3, where it is in contact with the ball V, separates from the outer peripheral surface 31A of the rotor body 31. Also, as shown in Figures 7(a) to (c), when a portion of the outer circumference 321 of the outer peripheral member 32 separates from the outer peripheral surface 31A of the rotor body 31, the separated portion of the outer circumference 321 bulges outward in the radial direction of the rotor 3.

[0056] As described above, when the outer peripheral portion 321 of the outer peripheral member 32 is in contact with the ball V and displaced in the opposite direction to the rotational direction of the rotor 3 relative to the outer peripheral surface 31A of the rotor body 31, the outer peripheral member 32 of the rotor 3 becomes less likely to slip on the surface of the ball V. Therefore, friction of the surface of the ball V by the outer peripheral member 32 of the rotor 3 becomes less likely. As a result, wear of the ball V by the rotor 3 can be suppressed.

[0057] Furthermore, by separating a portion of the outer periphery 321 of the outer peripheral member 32 from the outer peripheral surface 31A of the rotor body 31, the outer peripheral portion 321 of the outer peripheral member 32 can be displaced more significantly relative to the outer peripheral surface 31A of the rotor body 31. Therefore, friction of the ball V surface by the outer peripheral member 32 can be further suppressed.

[0058] Even if the outer circumference 321 of the outer circumference member 32 is displaced relative to the outer circumference 31A of the rotor body 31 in the opposite direction to the rotation direction of the rotor 3, the forward movement speed of the ball V increases due to the rotational force of the rotor 3. Then, the ball V is launched from the ball launcher 1 at a speed corresponding to the rotation speed of the rotor 3. When the ball V is fired, it separates from the outer circumference 321 of the outer circumference member 32 in the rotor 3, and the displacement of the outer circumference 321 of the outer circumference member 32 with respect to the outer circumference surface 31A of the rotor body 31 is eliminated.

[0059] In the ball launcher 1, it is not necessarily required that both rotors 3 have the above-described configuration. In other words, only one of the first rotor 3a and the second rotor 3b may have the above-described configuration. In this case, the other of the first rotor 3a and the second rotor 3b may have a configuration in which, for example, an outer peripheral member 32 is bonded to the entire outer peripheral surface 31A of the rotor body 31. Even if only one of the first rotor 3a and the second rotor 3b has the above-described configuration, wear of the ball V by the rotor 3 can be suppressed. Furthermore, even if the ball launcher 1 is equipped with three or more rotors 3, the effect of suppressing wear of the ball V by the rotor 3 can be obtained if at least one rotor 3 has the above-described configuration.

[0060] In the rotor 3, a lubricant may be sandwiched between the outer circumferential surface 31A of the rotor body 31 and the inner circumferential surface of the outer circumferential portion 321 of the outer circumferential member 32. Examples of lubricants include lubricating oil, grease, solid lubricant, and powder. Lubricating oil may be, for example, mineral oil, synthetic oil, vegetable oil, or animal oil. Solid lubricants may be, for example, graphite, molybdenum disulfide, or PTFE. When using powder as a lubricant, a powder with particle size and material appropriate to the materials of the rotor body 31 and the outer circumferential member 32 should be selected.

[0061] By inserting a lubricant between the outer circumferential surface 31A of the rotor body 31 and the inner circumferential surface of the outer circumferential portion 321 of the outer circumferential member 32, the outer circumferential portion 321 of the outer circumferential member 32 becomes more easily displaced relative to the outer circumferential surface 31A of the rotor body 31. Therefore, the displacement of the outer circumferential portion 321 of the outer circumferential member 32 relative to the outer circumferential surface 31A of the rotor body 31 that occurs when a ball V is sandwiched between the two rotors 3 can be promoted. Consequently, friction of the surface of the ball V by the outer circumferential member 32 of the rotor 3 can be further suppressed.

[0062] [Example 1] Next, a first modified example of the rotor of the ball launching device according to this embodiment will be described with reference to Figure 8. Figure 8 is a diagram illustrating the configuration of the rotor 3 according to the first modified example. Figure 8 is a part of the cross-sectional view of the rotor 3 in the direction of the rotation axis.

[0063] In this modified rotor 3, the outer circumferential surface 31A of the rotor body 31 is covered by the outer circumferential member 32. The rotor body 31 also has a cylindrical member 311, a first side member 312, and a second side member 313. On both sides of the rotor body 31, the ends 322 on both sides of the outer circumferential member 32 are fixed to the rotor body 31 using fixing ring members 34 and 35. However, in this modified example, the shape of the outer circumferential surface 31A of the rotor body 31 and the outer circumferential portion 321 of the outer circumferential member 32 differs from that of the above-described embodiment.

[0064] In the rotor 3 of this modification, the outer peripheral wall surface of the cylindrical member 311 of the rotor body 31 has a constricted shape in the central part in the direction of the rotation axis of the rotor 3 (left-right direction in Figure 8). As a result, as shown in Figure 8, the cross-sectional shape of the outer peripheral surface 31A of the rotor body 31 in the direction of the rotation axis of the rotor 3 has a V-shape in which the central part is recessed toward the inside of the rotor 3.

[0065] Furthermore, the cross-sectional shape of the outer peripheral portion 321 of the outer peripheral member 32 in the direction of the rotation axis of the rotor 3 also has a V-shape in which the central part is recessed toward the inside of the rotor 3, so as to follow the outer peripheral surface 31A of the rotor body 31. Therefore, in this modified example as well, the inner peripheral surface of the outer peripheral portion 321 of the outer peripheral member 32 is in contact with the outer peripheral surface 31A of the rotor body 31. Here, the outer The inclination angle of the V-shaped portion of the outer circumferential surface 31A and the outer circumferential portion 321 of the outer circumferential member 32 may be, for example, 1° to 5°. The inclination angle of the V-shaped portion of the outer circumferential surface 31A of the rotor body 31 and the outer circumferential portion 321 of the outer circumferential member 32 is not limited to 1° to 5°.

[0066] With this configuration, the cross-sectional shape of the outer surface 32A of the outer peripheral portion 321 of the outer peripheral member 32 that contacts the ball V, in the direction of the rotation axis of the rotor 3, is also V-shaped. As a result, the contact area between the ball V and the outer peripheral surface 32A when the ball V is sandwiched between the two rotors 3 is increased compared to the case where the cross-sectional shape of the outer peripheral surface 32A in the direction of the rotation axis of the rotor 3 is substantially straight. In addition, the diameter of the central portion (hereinafter simply referred to as the central portion) of the outer peripheral portion 321 of the outer peripheral member 32 in the direction of the rotation axis of the rotor 3 becomes smaller than the diameter of the lateral portion (hereinafter simply referred to as the lateral portion) in the direction of the rotation axis of the rotor. As a result, the tension of the central portion of the outer peripheral portion 321 of the outer peripheral member 32 is weaker compared to the case where the diameter of the central portion of the outer peripheral portion 321 of the outer peripheral member 32 is equal to the diameter of the lateral portion, as in the embodiment described above.

[0067] As a result, when friction occurs between the ball V sandwiched between the two rotors 3 and the outer circumference 321 of the outer circumference member 32, the outer circumference 321 of the outer circumference member 32 is more easily displaced relative to the outer circumference surface 31A of the rotor body 31. Therefore, friction on the surface of the ball V by the outer circumference member 32 can be further suppressed.

[0068] Furthermore, the cross-sectional shape of the outer circumferential surface 31A of the rotor body 31 and the outer circumferential portion 321 of the outer circumferential member 32 in the direction of the rotation axis of the rotor 3 is not limited to a V-shape. For example, the cross-sectional shape of the outer circumferential surface 31A of the rotor body 31 and the outer circumferential portion 321 of the outer circumferential member 32 in the direction of the rotation axis of the rotor 3 may have a concave shape in which the central portion is recessed toward the inside of the rotor 3. Even in this case, the diameter of the central portion of the outer circumferential portion 321 of the outer circumferential member 32 will be smaller than the diameter of the lateral portion. As a result, the tension in the central portion of the outer circumferential portion 321 of the outer circumferential member 32 will be weaker compared to the case where the diameter of the central portion of the outer circumferential portion 321 of the outer circumferential member 32 is equal to the diameter of the lateral portion. Therefore, when friction occurs between the ball V sandwiched between the two rotors 3 and the outer circumferential portion 321 of the outer circumferential member 32, the outer circumferential portion 321 of the outer circumferential member 32 will be more easily displaced relative to the outer circumferential surface 31A of the rotor body 31.

[0069] Furthermore, in the ball launcher 1, it is not necessarily required that both rotors 3 have the same configuration. That is, one of the first rotor 3a and the second rotor 3b may adopt the configuration according to the above embodiment, and the other may adopt the configuration according to the first modified example. Similarly, if the ball launcher 1 is equipped with three or more rotors 3, it is not necessary that all three or more rotors 3 have the same configuration.

[0070] [Differentiation 2] Next, a second modified example of the rotor of the ball launching device according to this embodiment will be described with reference to Figure 9. Figure 9 is a diagram illustrating the configuration of the rotor 3 according to the second modified example. Figure 9 shows the outer circumferential surface of the rotor 3. In Figure 9, circle V represents a ball sandwiched between two rotors 3.

[0071] In this modified rotor 3, the outer circumferential surface 31A of the rotor body 31 is covered by the outer circumferential member 32. However, in this modified rotor, the method of attaching the outer circumferential member 32 to the rotor body 31 differs from that of the above-described embodiment.

[0072] In this modified example, the width of the outer peripheral member 32 (the width in the rotation axis direction of the rotor 3) is equal to the width of the rotor body 31. When a ball V is sandwiched between the two rotors 3, the outer peripheral surface 32A of the central part of the outer peripheral portion 321 of the outer peripheral member 32 comes into contact with the ball V. Therefore, in the outer peripheral portion 321 of the outer peripheral member 32, the outer peripheral surface 32A in the central part comes into contact with the ball V. A contact portion 321a is formed. On the other hand, in the outer peripheral portion 321 of the outer peripheral member 32, the outer peripheral surface 32A does not come into contact with the ball V in the lateral portions 321b located on both sides of the contact portion 321a. The width of the area that actually comes into contact with the ball V on the outer peripheral surface 32A of the outer peripheral portion 321 of the outer peripheral member 32 varies depending on the diameter of the ball V and how much the ball V is compressed when sandwiched between the two rotors 3. Therefore, the width of the contact portion 321a in the outer peripheral portion 321 of the outer peripheral member 32 is determined taking these factors into consideration.

[0073] In this modified example, the lateral portion 321b of the outer peripheral portion 321 of the outer peripheral member 32 is screwed to the outer peripheral surface 31A of the rotor body 31 by screws 38. As shown in Figure 9, the lateral portion 321b of the outer peripheral portion 321 of the outer peripheral member 32 is screwed to the outer peripheral surface 31A of the rotor body 31 by a plurality of screws 38 arranged along the outer circumference of the lateral portion 321b. However, the method of fixing the lateral portion 321b of the outer peripheral portion 321 of the outer peripheral member 32 to the outer peripheral surface 31A of the rotor body 31 is not limited to this screwing method. For example, the lateral portion 321b of the outer peripheral portion 321 of the outer peripheral member 32 may be fixed by sandwiching it between a ring-shaped fixing member having approximately the same width as the lateral portion 321b and the outer peripheral surface 31A of the rotor body 31.

[0074] According to this, in the rotor 3, the lateral portions 321b located on both sides of the contact portion 321a on the outer circumference 321 of the outer peripheral member 32 are fixed to the rotor body 31. However, the contact portion 321a of the outer circumference 321 of the outer peripheral member 32 is not fixed to the rotor body 31. Therefore, the contact portion 321a of the outer circumference 321 of the outer peripheral member 32 is displaceable relative to the outer peripheral surface 31A of the rotor body 31.

[0075] When the rotor 3 is rotating at high speed, if a ball V comes into contact with the outer surface 32A of the contact portion 321a on the outer circumference 321 of the outer circumference member 32, friction occurs between the outer surface 32A of the contact portion 321a and the ball V. In this modified configuration, the contact portion 321a of the outer circumference 321 of the outer circumference member 32 is displaced relative to the outer circumference 31A of the rotor body 31 in the opposite direction to the rotation direction of the rotor 3. Furthermore, if the amount of displacement of the contact portion 321a on the outer circumference 321 of the outer circumference member 32 relative to the outer circumference 31A of the rotor body 31 increases, a part of the contact portion 321a separates from the outer circumference 31A of the rotor body 31.

[0076] Therefore, even with the configuration according to this modified example, the outer peripheral member 32 of the rotor 3 is less likely to slip on the surface of the ball V. As a result, friction of the surface of the ball V by the outer peripheral member 32 of the rotor 3 is less likely to occur. Thus, wear of the ball V by the rotor 3 can be suppressed.

[0077] [Test results of the launch test] The following describes the results of launch tests conducted using examples and comparative examples of ball launching devices. In these launch tests, volleyballs were launched using a ball launching device equipped with two rotors. After launch, it was checked whether or not there were scratches on the surface of the ball caused by friction from the rotors.

[0078] 《Configuration of the ball launching device》 Rotor body: Metal rotor Rotor outer diameter: 220mm Rotor width: 160mm Distance between the two rotors (minimum distance between outer surfaces): 155 mm 《Ball used》 Volleyball size 5 (Mikasa Corporation, V300W) Ball diameter: Approximately 210 mm Ball air pressure: 0.031 MPaG

[0079] 《Configuration of the rotor according to the embodiment》 A cylindrical piece of natural rubber, which forms the outer perimeter, was fixed to both sides of the rotor body (metal rotor). For the first rotor, the cross-sectional shape in the direction of the rotor's rotation axis is substantially straight for the outer surface of the rotor body and the outer circumference of the outer peripheral member. For the second rotor, the cross-sectional shape in the direction of the rotor's rotation axis is V-shaped (inclination angle of 2°) for the outer surface of the rotor body and the outer circumference of the outer peripheral member. Dimensions of the cylindrical natural rubber according to Example 1: Thickness 1 mm, inner diameter 140 mm Dimensions of the cylindrical natural rubber in Example 2: Thickness 1 mm, inner diameter 127 mm

[0080] 《Rotor configuration related to comparative example》 A 10mm thick layer of urethane rubber was fixed to the outer surface of the rotor body (metal rotor).

[0081] The launch tests were conducted multiple times, varying the rotor's rotation speed (revolutions per minute, peripheral speed). After each launch, the surface of the ball was visually inspected, and any scratches larger than 1 mm were evaluated as damaged. Figure 10 shows an example of scratches on the ball's surface caused by rotor friction.

[0082] Table 1: Test results of Example 1 TIFF0007829642000002.tif36153

[0083] Table 2: Test results for Example 2 TIFF0007829642000003.tif36153

[0084] Table 3: Test results of comparative examples TIFF0007829642000004.tif36153

[0085] As shown in Tables 1 and 2 above, no scratches appeared on the surface of the ball in any of the launches in Examples 1 and 2. On the other hand, as shown in Table 3 above, scratches appeared on the surface of the ball in the comparative example in all launches except No. 5.

[0086] [Evaluation results for natural rubber] The following describes the results of evaluation tests conducted on the natural rubber used as the outer periphery member in Examples 1 and 2 described above. For the evaluation tests, tensile tests were performed on natural rubber test pieces, and the elongation of the test pieces was measured.

[0087] Method of tensile testing A rectangular plate-shaped test specimen measuring 1 mm thick, 60 mm long, and 20 mm wide was used. In the tensile test, the specimen was gripped near both ends (17.5 mm from the ends) using the grips of the testing machine (Autograph, manufactured by Shimadzu Corporation), and the specimen was pulled at a predetermined speed (60 mm / min). The amount of elongation at a distance of 25 mm between the fixed points of the grips was measured. The specimen was secured by wrapping it around a stainless steel rod (6 mm in diameter) and gripping the rod and the specimen together. The tensile test was conducted in an indoor environment at a temperature of 25°C.

[0088] Table 4 below shows the measurement results when tensile tests were conducted with tensile loads of 8N and 12N. Table 4: Tensile test results TIFF0007829642000005.tif22170

[0089] Based on the results of the above firing test, it is considered that if an elastic material with an elongation of 42% at a tensile stress of 0.4 MPa, or an elastic material with an elongation of 88% at a tensile stress of 0.6 MPa, is used as the outer peripheral member of the rotor according to the present invention, wear of the balls due to friction of the rotor can be suppressed.

[0090] Furthermore, the elastic body used as the outer peripheral member of the rotor according to the present invention preferably has an elongation of 16-95% when the tensile stress is 0.4 MPa, or an elongation of 24-143% when the tensile stress is 0.6 MPa in the tensile test described above. In addition, considering that the elastic body used as the outer peripheral member of the rotor will be used repeatedly, it is desirable that the magnitude of plastic strain with respect to tensile stress be as small as possible. For example, it is preferable that the plastic strain of the elastic body after applying a tensile load until the elongation reaches 200% and then removing the tensile load is 3% or less. [Explanation of symbols]

[0091] 1. Ball launcher 2. Main unit 21. Stand 22. Rotor support section 221...Support shaft 222 ··Support plate 223 ··Support frame 3. Rotor 3a ··First rotor 3b · Second rotor 31. Rotor body 31A...Outer surface 32. Peripheral member 32A...Outer surface 321 ··Outer perimeter 322 ··end 33. Rotating shaft member 34, 35... Fixing ring components 4. Motor

Claims

1. A ball launching device that clamps a ball between multiple rotors and launches the ball using the rotational force of the multiple rotors, At least one of the aforementioned plurality of rotors, A rotor body is supported on the main body of the ball launching device via a rotating shaft member, It has an outer peripheral member made of an elastic material that is attached to the rotor body so as to cover the outer peripheral surface of the rotor body, In the above-mentioned at least one rotor, The outer peripheral member is attached to the rotor body such that the outer peripheral portion of the outer peripheral member, which covers the outer peripheral surface of the rotor body, is displaceable relative to the outer peripheral surface of the rotor body. Ball launcher.

2. In the above-mentioned at least one rotor, When the ball is caught between the rotating rotors, the outer circumference of the outer peripheral member is displaced in a direction opposite to the rotation direction of at least one rotor relative to the outer peripheral surface of the rotor body, so that a part of the outer circumference separates from the outer peripheral surface of the rotor body. The ball launching device according to claim 1.

3. In the above-mentioned at least one rotor, The portion of the outer peripheral member other than the outer peripheral portion, or the portion of the outer peripheral portion of the outer peripheral member other than the contact portion where the outer peripheral surface contacts the ball, is fixed to the rotor body. The ball launching device according to claim 1.

4. The outer peripheral member extends to the vicinity of the outer circumference of both sides of the rotor body, The portion of the outer peripheral member other than the outer peripheral portion is the portion that covers the vicinity of the outer peripheral portion of both sides of the rotor body. The ball launching device according to claim 3.

5. In the outer peripheral portion of the outer peripheral member, the central portion in the rotation axis direction of at least one rotor is the contact portion, The portion of the outer peripheral member other than the contact portion is a lateral portion of the outer peripheral member located on both sides of the contact portion in the rotation axis direction of at least one rotor. The ball launching device according to claim 3.

6. In the above-mentioned at least one rotor, A lubricant is sandwiched between the outer circumferential surface of the rotor body and the inner circumferential surface of the outer circumferential portion of the outer circumferential member. The ball launching device according to claim 1.

7. In the above-mentioned at least one rotor, The outer circumferential surface of the rotor body and the outer circumferential portion of the outer circumferential member have a cross-sectional shape in the direction of the rotation axis of at least one rotor, which is V-shaped or concave. The ball launching device according to claim 1.

8. The ball is sandwiched between multiple rotors, and the rotational force of the multiple rotors A rotor for a ball launching device that launches balls, A rotor body is supported on the main body of the ball launching device via a rotating shaft member, It has an outer peripheral member made of an elastic material that is attached to the rotor body so as to cover the outer peripheral surface of the rotor body, The outer peripheral member is attached to the rotor body such that the outer peripheral portion of the outer peripheral member, which covers the outer peripheral surface of the rotor body, is displaceable relative to the outer peripheral surface of the rotor body. rotor.

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