Rotary apparatus

Abstract

To provide a rotary apparatus which can avoid interference in an axial direction.SOLUTION: A rotary apparatus 1 comprises: a first rotor 53 having a first flange 56; a second rotor 52 having a second flange 57; a third rotor 49; a first component 54 which rotatably supports the first rotor 53 to the second rotor 52 in a radial direction; and a second component 13 which rotatably supports the second rotor 52 to the third rotor 49 in the radial direction. In the axial direction, the first flange 56 and the second flange 57 are located between the first component 54 and the second component 13, and there is a ring 17 which slidably contacts the first flange 56 and the second flange 57 in the axial direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a rotating device.

Background Art

[0002] Patent Document 1 discloses a geared motor having a motor and a speed reducer arranged axially.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When parts of a motor or a speed reducer are arranged axially, it is desirable to avoid interference between the parts.

[0005] Therefore, one of the problems of the present invention is to provide a rotating device capable of avoiding axial interference.

Means for Solving the Problems

[0006] A rotating device according to an aspect of the present invention includes a first rotating body having a first flange, a second rotating body having a second flange, a third rotating body, a first component that rotatably supports the first rotating body with respect to the second rotating body in the radial direction, and a second component that rotatably supports the second rotating body with respect to the third rotating body in the radial direction. Axially, the first flange and the second flange are between the first component and the second component, and there is a ring that slidably contacts the first flange and the second flange.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing the structure of the rotating device 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1. FIG. 2 is a cross-section along a virtual plane including the rotation axis x. This rotating device 1 is a rotating device having a motor and a speed reducer for reducing the rotation of the motor, and is incorporated in, for example, an electric assist bicycle. The rotating device 1 includes a housing 2. The housing 2 generally has, for example, an overall substantially cylindrical shape. The housing 2 is fixed to, for example, the frame of a bicycle. Note that the bicycle includes all types of bicycles such as road bicycles, cross bicycles, mountain bicycles, and city bicycles.

[0009] A crankshaft 3 is rotatably supported in the housing 2 around the rotation axis x. In this example, the rotation axis x coincides with the central axis of the housing 2. The crankshaft 3 has one end 3a on one side S1 in the direction along the rotation axis x (hereinafter referred to as the "rotation axis direction"), and the other end 3b on the other side S2 opposite to the one side S1. Both the one end 3a and the other end 3b project from the housing 2 in the rotation axis direction. Crank arms (not shown) extending in a direction orthogonal to the rotation axis x are respectively attached to the one end 3a and the other end 3b. A pedal (not shown) is attached to the tip of the crank arm. A chain ring (not shown) is further attached to the crank arm attached to the one end 3a.

[0010] The housing 2 has a housing (hereinafter referred to as the "motor housing") 20 that houses the motor 4, a housing (hereinafter referred to as the "gear housing") 21 that houses the speed reducer 5, and a cover (hereinafter referred to as the "gear cover") 22. The motor housing 20, the gear housing 21, and the gear cover 22 are coupled to each other by fastening components 23 such as bolts extending in the rotational axis direction. An annular member (hereinafter referred to as a "gasket") 24 seals between the motor housing 20 and the gear housing 21. An annular member (hereinafter referred to as a "gasket") 25 seals between the gear housing 21 and the gear cover 22. The housing 2 is formed of, for example, a metal material or a resin material. From the viewpoint of thermal conductivity, it is preferable that the motor housing 20 and the gear housing 21 are formed of a metal material. The gaskets 24 and 25 are formed of a metal material or a resin material having elasticity or resilience.

[0011] The motor housing 20 has a cylindrical outer portion (hereinafter referred to as the "outer peripheral portion") 20a centered on the rotational axis x, a cylindrical inner portion (hereinafter referred to as the "inner peripheral portion") 20b centered on the rotational axis x, and a wall 20c connecting the outer peripheral portion 20a and the inner peripheral portion 20b. In this example, the wall 20c connects the ends of the outer peripheral portion 20a and the inner peripheral portion 20b on the other side S2. The outer peripheral portion 20a surrounds the motor 4 from the outer peripheral side in the radial direction orthogonal to the rotational axis x. The inner peripheral portion 20b is disposed inside the motor 4. The inner peripheral surface of the inner peripheral portion 20b faces the outer peripheral surface of the crankshaft 3. In this example, the wall 20c extends along a virtual plane orthogonal to the rotational axis x. That is, the wall 20c faces the motor 4 in the rotational axis direction and forms a bottom.

[0012] A bearing 10 is disposed between the inner peripheral end of the wall 20c and the outer peripheral surface of the crankshaft 3. The bearing 10 is a bearing having rolling elements, for example, a ball bearing. In this way, the motor housing 20 supports the crankshaft 3 so as to be relatively rotatable via the bearing 10 at the inner peripheral end of the wall 20c. The housing 2 further has an annular end cover 26. The end cover 26 covers the other side S2 of the bearing 10 along the rotational axis direction. The end cover 26 is fixed to the wall 20c by fastening components 27 such as screws, for example. The other end 3b of the crankshaft 3 projects from the housing 2 to the other side S2 through a hole (through hole) of the end cover 26 formed along the rotation axis x.

[0013] FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2. Referring to FIGS. 2 and 3 together, the motor 4 has a stator 40 and a rotor 41 that is relatively rotatable with respect to the stator 40. The stator 40 has a magnetic body (hereinafter referred to as a "yoke"), that is, a stator core 42, a coil 43, and an insulator 44. The stator core 42 is formed from a laminate in which a plurality of annular silicon steel sheets or electromagnetic steel sheets are laminated in the rotational axis direction. The stator core 42 is fixed to the inner peripheral surface of the outer peripheral portion 20a of the motor housing 20. The stator core 42 has a plurality of teeth 42a arranged in the circumferential direction around the rotation axis x. The coil 43 is wound around each tooth 42a. The insulator 44 insulates the stator core 42 and the coil 43.

[0014] The stator 40 is covered with a predetermined member 45 (see Fig. 2). The predetermined member 45 is formed of, for example, a resin material having thermal conductivity. A substrate (hereinafter referred to as "printed circuit board") 46 is fixed to the other side S2 of the predetermined member 45. The printed circuit board 46 is provided with a plurality of electronic components such as wiring for electrically connecting a coil, a temperature sensor for detecting temperature, and a magnetic sensor. The printed circuit board 46 is electrically connected to, for example, the outer peripheral surface of the rotating device 1 or another substrate provided outside. Alternatively, the printed circuit board 46 may be composed of a printed circuit board and a plurality of bus bars, and the printed circuit board and the plurality of bus bars may be electrically connected. A sensor (not shown) for detecting the torque acting on the crankshaft 3 is incorporated in the rotating device 1. A control circuit capable of determining the current value of the current supplied to the coil 43 based on the detected value of the torque from this sensor is mounted on the printed circuit board 46. Current is supplied to the coil 43 from, for example, a battery (not shown) mounted on a bicycle. In this way, the control circuit can control the rotational speed of the motor 4 according to the value of the torque of the crankshaft 3.

[0015] The rotor 41 has a magnet 47 and a magnetic body (hereinafter referred to as "yoke") 48. The yoke 48 is formed of, for example, a magnetic material. A plurality of magnets 47 arranged in the circumferential direction are supported by the yoke 48. The magnet 47 faces the outer peripheral surface of the pole portion (hereinafter referred to as "tooth") 42a of the stator core 42 with a predetermined magnetic gap. When current is supplied to the coil 43, the rotor 41 can rotate relative to the stator 40 about the rotation axis x due to the magnetic interaction between the coil 43 and the magnet 47. Note that the yoke 48 may be, for example, a cylindrical member centered on the rotation axis x. Also, the magnet 47 may be a single cylindrical permanent magnet, or a plurality of permanent magnets may be connected to each other in the circumferential direction to form a cylindrical shape.

[0016] The rotor 41 is attached to a motor shaft (third rotating body) 49. For example, the rotor 41 is fixed to the outer peripheral surface of the motor shaft 49, for example, by press-fitting. The motor shaft 49 is formed, for example, in a cylindrical shape centered on the rotation axis x. The motor shaft 49 extends from inside the motor housing 20 to inside the gear housing 21. The motor shaft 49 is supported so as to be relatively rotatable via a bearing 11 on the outer peripheral surface of the inner peripheral portion 20b of the motor housing 20 adjacent to the end on the other side S2. The bearing 11 is a bearing having rolling elements, for example, a ball bearing. In the rotation axis direction, the inner peripheral surface of the motor shaft 49 faces the outer peripheral surface of the crankshaft 3 on one side S1 from the inner peripheral portion 20b. In the gear housing 21, a speed reducer 5 described later is connected to the end on one side S1 of the motor shaft 49.

[0017] The gear housing 21 has a cylindrical outer portion (hereinafter referred to as the "outer peripheral portion") 21a centered on the rotation axis x and a wall 21b extending inward from the outer peripheral portion 21a toward the rotation axis x. In this example, the wall 21b extends inward from the end on the other side S2 of the outer peripheral portion 21a. The gear cover 22 has a cylindrical outer portion (hereinafter referred to as the "outer peripheral portion") 22a centered on the rotation axis x and a cylindrical inner portion (hereinafter referred to as the "inner peripheral portion") 22b having a smaller diameter and located inside the outer peripheral portion 22a and centered on the rotation axis x. The speed reducer 5 is housed in the gear housing 21 and the gear cover 22. The speed reducer 5 is arranged side by side with the motor 4 in the rotation axis direction. The wall 21b is formed in an annular shape extending across between the motor 4 and the speed reducer 5. That is, the speed reducer 5 is arranged on the opposite side of the motor 4 with the wall 21b interposed therebetween in the rotation axis direction.

[0018] The speed reducer 5 is configured as a cycloid speed reducer as an example. The speed reducer 5 has a first gear 50 supported on the outer peripheral surface of the motor shaft 49 via a bearing 12, and a second gear 51 disposed on the outer peripheral side of the first gear 50. The bearing 12 is a bearing having rolling elements, for example, a ball bearing. The second gear 51 is fixed to the inner peripheral surface of the outer peripheral portion 21a. A plurality of teeth (not shown) are formed in the circumferential direction on the outer peripheral surface of the first gear 50. On the other hand, a plurality of teeth (not shown) are formed in the circumferential direction on the inner peripheral surface of the second gear 51. The teeth of the first gear 50 and the teeth of the second gear 51 mesh with each other. Thus, the first gear 50 and the second gear 51 fit into each other in the radial direction. In this example, the central axis of the cylindrical surface forming the outer peripheral surface of the motor shaft 49 is defined to be eccentric from the rotation axis x in the region supporting the first gear 50. As a result, the rotational speed of the motor shaft 49 is reduced by a predetermined reduction ratio by the first gear 50 and the second gear 51.

[0019] The speed reducer 5 has a carrier (second rotating body) 52 disposed on one side S1 in the rotational axis direction of the first gear 50 and the second gear 51. The carrier 52 is formed, for example, in a cylindrical shape around the rotation axis x. The carrier 52 is connected to the first gear 50 in the rotational axis direction. The carrier 52 is configured to decelerate the rotational force of the motor shaft 49 by a predetermined reduction ratio via the first gear 50 and the second gear 51 and transmit it to an output shaft described later. The carrier 52 is supported on the outer peripheral surface of the motor shaft 49 via a bearing (second component) 13 on its inner peripheral surface, while being supported on the inner peripheral surface of the outer peripheral portion 21a of the gear housing 21 via a bearing 14 on its outer peripheral surface. The bearing 13 is a bearing having rolling elements, for example, a ball bearing. The bearing 14 is a bearing having rolling elements, for example, a needle bearing. Note that at least a part of the region including the meshing region of the teeth of the first gear 50 and the second gear 51 is covered with a fluid, that is, a lubricant W1. The lubricant W1 contains additives such as a filler for improving slipperiness, for example.

[0020] The speed reducer 5 has a cylindrical output shaft 53 around the rotation axis x. The output shaft 53 is arranged side by side with the motor shaft 49 in the rotation axis direction. The output shaft 53 is supported on the inner peripheral surface of the inner peripheral portion 22b of the gear cover 22 via the bearing 15 at its outer peripheral surface (first side surface) 53a, while being supported on the outer peripheral surface of the crankshaft 3 via the bearing 16 at its inner peripheral surface 53b. The inner peripheral surface (second side surface) 52a of the carrier 52 facing each other and the outer peripheral surface 53a of the output shaft 53 are connected via a one-way clutch (first component) 54. Similarly, the inner peripheral surface 53b of the output shaft 53 facing each other and the outer peripheral surface of the crankshaft 3 are connected via a one-way clutch 55. Note that at least a part of the one-way clutches 54 and 55 is covered with a fluid, i.e., a lubricant W2. This lubricant W2 is a lubricant different from the lubricant W1 covering the first gear 50 and the second gear 51. For example, the lubricant W2 does not contain additives such as fillers for improving the aforementioned slip.

[0021] The one-way clutches 54 and 55 are configured to transmit the rotational force of the carrier 52 to the output shaft 53 in one direction around the rotation axis x (i.e., rotate the carrier 52 and the output shaft 53 in the same direction), while allowing relative rotation between the carrier 52 and the output shaft 53 in the other direction around the rotation axis x. The end of the other side S2 of the output shaft 53 faces the motor shaft 49, while the end of the one side S1 of the output shaft 53 is arranged outside the gear cover 22. The end of the one side S1 of the output shaft 53 is connected to a chain ring fixed to the crank arm on the one side S1. Thus, the rotational force generated by the motor 4 is decelerated by the speed reducer 5 at a predetermined reduction ratio and transmitted from the output shaft 53 to the chain ring.

[0022] FIG. 4 is an enlarged cross-sectional view showing a part of the cross-sectional view of FIG. 2. Referring to FIGS. 2 and 4 together, a first flange 56 is formed on the outer peripheral surface 53a of the output shaft 53 adjacent to the end portion on the other side S2 of the output shaft 53. The first flange 56 is formed in an annular shape around the rotation axis x. The first flange 56 is disposed between the one-way clutch 54 and the bearing 13. The first flange 56 projects from the outer peripheral surface 53a of the output shaft 53 toward the inner peripheral surface 52a of the carrier 52 facing the outer peripheral surface 53a. A predetermined gap is formed between the end portion on the outer peripheral side of the first flange 56 and the inner peripheral surface 52a of the carrier 52. That is, the end portion on the outer peripheral side of the first flange 56 is separated from the inner peripheral surface 52a in the radial direction and is in a non-contact state. The one-way clutch 54 is surrounded by the inner peripheral surface 52a, the outer peripheral surface 53a, and the first flange 56.

[0023] On the other hand, in a region at least partially facing the outer peripheral surface 53a of the output shaft 53, a second flange 57 is formed on the inner peripheral surface 52a of the carrier 52 on the other side S2 of the first flange 56. The second flange 57 is formed in an annular shape around the rotation axis x. The second flange 57 is disposed between the bearing 13 and the one-way clutch 54. The second flange 57 projects from the inner peripheral surface 52a of the carrier 52 toward the outer peripheral surface 53a of the output shaft 53. A predetermined gap is formed between the end portion on the inner peripheral side of the second flange 57 and the outer peripheral surface 53a of the output shaft 53. That is, the end portion on the inner peripheral side of the second flange 57 is separated from the outer peripheral surface 53a and is in a non-contact state. In the rotational axis direction, the surface on one side S1 of the second flange 57 faces the surface on the other side S2 of the first flange 56 via the ring 17. Note that in the rotational axis direction, the surface on one side S1 of the second flange 57 may be configured to face the surface on the other side S2 of the first flange 56 without the ring 17.

[0024] In the direction of the rotation axis, a ring 17 is disposed between the first flange 56 and the second flange 57. The ring 17 is formed so as to extend annularly around the rotation axis x. The ring 17 is formed, for example, from a washer made of a resin material or a metal material. The ring 17 is sandwiched between the first flange 56 and the second flange 57. In this example, the inner peripheral side end portion of the ring 17 is fitted into the outer peripheral surface 53a of the output shaft 53. However, the ring 17 can be slidably contacted with both the first flange 56 and the second flange 57 during relative rotation between the carrier 52 and the output shaft 53. That is, the first flange 56 and the second flange 57 can rotate relative to each other via the ring 17.

[0025] The static friction coefficient or the dynamic friction coefficient between the first flange 56 and the ring 17 may be smaller than the static friction coefficient or the dynamic friction coefficient between the first flange 56 and the second flange 57. Also, the static friction coefficient or the dynamic friction coefficient between the second flange 57 and the ring 17 may be smaller than the static friction coefficient or the dynamic friction coefficient between the first flange 56 and the second flange 57. Further, a fluid, i.e., a lubricant, may be interposed between the first flange 56 and the ring 17 or between the second flange 57 and the ring 17. Also, when the first flange 56 and the second flange 57 face each other without the ring 17 therebetween, a fluid, i.e., a lubricant, may be interposed between the first flange 56 and the second flange 57. Note that, in the direction of the rotation axis, the first flange 56 and the second flange 57 may have a greater rigidity with respect to the ring 17 to such an extent that the first flange 56 is received by the ring 17 and the second flange 57. In the direction of the rotation axis, the ring 17 may have a greater rigidity with respect to the first flange 56 and the second flange 57 to such an extent that the first flange 56 is received by the ring 17 and the second flange 57.

[0026] An example of the usage mode of the rotary device 1 as described above will be explained. When a user of a bicycle equipped with the rotary device 1 pedals to rotate the crank arm, the crankshaft 3 rotates around the rotation axis x. In this example, when viewed from one side S1, the crankshaft 3 rotates clockwise. When the torque sensor detects an increase in the torque acting on the crankshaft 3 that is equal to or greater than a predetermined threshold value, the control circuit of the printed circuit board 46, which is electrically connected from an external power source via another substrate, supplies current to the coil 43 of the motor 4. Due to the magnetic interaction between the coil 43 and the magnet 47, the rotor 41 rotates relative to the stator 40 around the rotation axis x. The rotational force generated by this rotation is transmitted from the motor shaft 49 to the speed reducer 5. The rotor 41 and the motor shaft 49 rotate counterclockwise when viewed from one side S1.

[0027] In the speed reducer 5, the rotational force is transmitted from the carrier 52 to the output shaft 53 while reducing the rotational speed by the engagement of the first gear 50 and the second gear 51. Note that due to the function of the speed reducer 5, the rotation direction of the motor shaft 49 is opposite to the rotation direction of the output shaft 53. That is, when viewed from one side S1, the output shaft 53 rotates clockwise. The rotational force with the reduced rotational speed is transmitted from the output shaft 53 to the chain ring and the crankshaft 3. As a result, the rotational force of the motor 4 assists the rotation of the crank arm of the bicycle while increasing its torque. In this way, the user of the bicycle can easily pedal even in a situation where the torque is large by the rotational force of the motor 4.

[0028] In such a rotating device 1, a ring 17 is disposed between a first flange 56 of an output shaft 53 and a second flange 57 of a carrier 52 that face each other in the axial direction of the rotating shaft. For example, when the bicycle falls over or when the output shaft 53 tries to move in the axial direction of the rotating shaft, the first flange 56 is received by the ring 17 and the second flange 57. Accordingly, interference in the axial direction of the rotating shaft between the output shaft 53 and the motor shaft 49 can be avoided. Further, the one-way clutch 54 is surrounded by the first flange 56, an outer peripheral surface 53a of the output shaft 53, and an inner peripheral surface 52a of the carrier 52. As a result, leakage of the lubricant W2 that covers at least a part of the one-way clutch 54 can be avoided. That is, mixing of the lubricant W1 that covers at least part of the first gear 50 and the second gear 51 and the lubricant W2 that covers at least part of the one-way clutch 54 can be avoided.

[0029] Note that although the rotating device 1 according to an embodiment of the present invention is incorporated in an electric assist bicycle, the rotating device 1 may be used for other applications such as industrial robots and machine tools instead of the electric assist bicycle. Further, although the speed reducer 5 described above constitutes a cycloid speed reducer as an example, other types of speed reducers such as a harmonic gear speed reducer may be used.

[0030] The embodiments described above are for facilitating understanding of the present invention and are not for limiting and interpreting the present invention. Further, the above-described embodiments do not limit the objects to which the present invention is applied, and the present invention may include any object as its application target. Each component included in the above embodiments, as well as its arrangement, material, conditions, shape, size, etc. are not limited to those illustrated and can be changed as appropriate. For example, the present invention includes differences that occur in implementation such as manufacturing tolerances. Further, components shown in different embodiments can be partially replaced or combined with each other within a range where there is no technical contradiction. Further, each configuration can be selectively combined as appropriate so as to achieve at least part of the above-described problems and effects.

Explanation of Reference Numerals

[0031] 1 Rotating machine, 10 Bearings, 11 Bearings, 12 Bearings, 13 Bearings (Second part), 14 Bearings, 15 Bearings, 16 Bearings, 17 Rings, 2 Housings, 20 Motor housing, 20a Outer part (outer peripheral part), 20b Inner part (inner peripheral part), 20c Wall, 21 Gear housing, 21a Outer part (outer peripheral part), 21b Wall, 22 Gear cover, 22a Outer part (outer peripheral part), 22b Inner part (inner peripheral part), 23 Fastening parts, 24 Annular member (gasket), 25 Annular member (gasket), 26 End cover, 27 Fastening parts, 3 Crankshaft, 3a One end, 3b The other end, 4 Motor, 40 Stator, 41 Rotor, 42 Magnetic body (stator core), 42a Magnetic pole part (teeth), 43 Coil, 44 Insulator, 45 Predetermined member, 46 Substrate (printed circuit board), 47 Magnet, 48 Magnetic body (yoke), 49 Motor shaft (third rotating body), 5 Reducer, 50 First gear, 51 Second gear, 52 Carrier (second rotating body), 52a Inner peripheral surface (second side surface), 53 Output shaft (first rotating body), 53a Outer peripheral surface (first side surface), 53b Inner peripheral surface, 54 One-way clutch (first part, clutch), 55 One-way clutch, 56 First flange, 57 Second flange, S1 One side, S2 The other side,, W1 Fluid (lubricant), W2 Fluid (lubricant), x Axis of rotation

Claims

1. a first rotating body having a first flange; a second rotating body having a second flange; a third rotating body; a first component that rotatably supports the first rotating body with respect to the second rotating body in the radial direction; a second component that rotatably supports the second rotating body with respect to the third rotating body in the radial direction, and in the axial direction, the first flange and the second flange are between the first component and the second component, a rotating device having a ring that slidably contacts the first flange and the second flange in the axial direction.

2. The rotating device according to claim 1, wherein the first flange and the second flange are rotatable relative to each other via the ring.

3. The rotating device according to claim 1 or 2, wherein the fluid inside the first component is different from the fluid inside the second component.

4. The first rotating body includes the first flange and a first side surface facing the first component, the second rotating body includes the second flange and a second side surface facing the first component, and the rotating device according to any one of claims 1 to 3, wherein the first component is surrounded by the first flange, the first side surface, and the second side surface.

5. The rotating device according to any one of claims 1 to 4, wherein the first component is a clutch.

6. The rotating device according to any one of claims 1 to 5, wherein the second component is a bearing.

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