Motor device

Abstract

The present invention provides a technology capable of miniaturizing the axial size of a brake. The motor device of the present invention comprises: a motor; a brake for braking the rotation of a motor shaft (14); and a brake housing (34) for accommodating the brake, wherein the brake comprises: a brake shoe (58); and a pushing mechanism (60) for pushing the brake shoe (58) toward the outer periphery of the motor shaft (14). When the pushing mechanism (60) pushes the brake shoe (58) toward the outer periphery of the motor shaft (14), the brake shoe (58) moves in the rotation direction of the motor shaft as the motor shaft (14) rotates, and the brake shoe (58) is sandwiched between the motor shaft (14) and the brake housing (34), thereby braking the rotation of the motor shaft (14).

Description

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2020-169887, filed on October 7, 2020. The entire contents of this Japanese application are incorporated herein by reference. Technical Field

[0002] The present invention relates to a motor device. Background Art

[0003] Patent Document 1 discloses a motor device incorporating a disc brake as a brake. A disc brake generally includes a brake rotor that rotates together with a motor shaft and a brake shoe that is pressed against the brake rotor to brake the motor shaft.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 10-225064

[0005] When a disc brake is used as a brake, the brake rotor must be positioned axially relative to the brake shoe to brake the rotation of the motor shaft. Consequently, the overall axial dimension of the brake tends to increase. The inventors, with the goal of miniaturizing the axial dimension of the brake, have discovered that conventional technology offers room for improvement. Summary of the Invention

[0006] One of the objects of the present invention is to provide a technique capable of reducing the axial dimension of a brake.

[0007] The motor device of the present invention comprises: a motor, which rotates a motor shaft; a brake, which brakes the rotation of the motor shaft; and a brake housing, which accommodates the brake, wherein the brake comprises: a brake shoe; and a pushing mechanism, which pushes the brake shoe toward the outer periphery of the motor shaft. When the pushing mechanism pushes the brake shoe toward the outer periphery of the motor shaft, the brake shoe moves in the rotation direction of the motor shaft as the motor shaft rotates, and the brake shoe is clamped between the motor shaft and the brake housing, thereby braking the rotation of the motor shaft.

[0008] According to the present invention, the axial dimension of the brake can be reduced in size. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a side sectional view of the motor device according to the first embodiment.

[0010] Figure 2 Yes Figure 1 Figure 2 is a diagram of a portion of the AA section.

[0011] Figure 3 yes Figure 2 Magnified image of .

[0012] Figure 4 It is a perspective view of the brake shoe according to the first embodiment.

[0013] Figure 5 This is an enlarged view showing a state in which the brake shoe in the motor device according to the first embodiment is in the process of moving from the brake release position to the brake position.

[0014] Figure 6 This is an enlarged view showing a state in which the brake shoe is located at the braking position in the motor device according to the first embodiment.

[0015] Figure 7 This is an enlarged view showing a state in which the brake shoe in the motor device according to the first embodiment is about to move from the braking position to the brake release position.

[0016] Figure 8 This is a schematic diagram showing a state in which the brake shoe is located at the brake release position in the motor device according to the second embodiment.

[0017] Figure 9 This is a schematic diagram showing a state in which the brake shoe is located at the braking position in the motor device according to the second embodiment.

[0018] Figure 10 yes Figure 9 An enlarged view of range A.

[0019] Figure 11 It is from Figure 3 This is a schematic diagram of the motor device according to the third embodiment when viewed from the same viewing angle.

[0020] Figure 12 This is a schematic diagram showing a state in which braking by the brake shoe is released in the motor device according to the fourth embodiment.

[0021] Figure 13 This is a schematic diagram showing a state where braking is performed by brake shoes in the motor device according to the fourth embodiment.

[0022] In the figure: 10-motor device, 12-industrial robot, 12a-joint part, 14-motor shaft, 16-motor, 18-brake, 20-housing, 22-reduction gear, 34-brake housing, 56A, 56B-wedge-shaped space, 58-brake shoe, 60-pushing mechanism, 68A, 68B-clamped part, 70A-first braking abutting surface, 70B-second braking abutting surface, 72A-abutted surface, 74-non-braking abutting surface, 76-pushing component, 100A, 100B-force-applying components, 130A, 130B-rollers. DETAILED DESCRIPTION

[0023] The following describes the embodiment. Identical components are denoted by the same reference numerals, and duplicate descriptions are omitted. In the accompanying drawings, components are omitted, enlarged, or reduced as appropriate for ease of description. The drawings are viewed according to the direction of the reference numerals.

[0024] (First embodiment)

[0025] refer to Figure 1 The motor device 10 of this embodiment is assembled to the joint portion 12a of the industrial robot 12. The industrial robot 12 of this embodiment is a collaborative robot that works in cooperation with a human.

[0026] The motor device 10 of the present embodiment mainly includes a motor shaft 14 , a motor 16 , a brake 18 , a housing 20 , and a reduction gear 22 .

[0027] The motor shaft 14 is used to transmit the rotational power generated by the motor 16 to the driven component (not shown). The driven component of this embodiment is the second arm of the industrial robot 12 connected to the first arm via the joint portion 12a. Hereinafter, the direction along the rotation center line CL of the motor shaft 14 will be referred to as the axial direction X, and the circumferential direction and radial direction of the circle centered on the rotation center line CL will be referred to as the "circumferential direction" and the "radial direction", respectively. In addition, one side on the axial direction X ( Figure 1 The left side of the axis is called the output side, and the other side on the axis X ( Figure 1 The right side of the output is called the opposite output side.

[0028] The motor 16 can rotate the motor shaft 14. The motor 16 includes a stator 24 fixed to a motor housing 32 (described later) and a rotor 26 that rotates integrally with the motor shaft 14. The motor 16 in this embodiment is a servo motor and includes a motor control unit 28 (e.g., a motor actuator) that controls the rotation of the motor 16 and a phase detection unit 30 (e.g., an encoder) that detects the rotational phase of the motor shaft 14.

[0029] The brake 18 can brake the rotation of the motor shaft 14. The brake 18 is arranged on the output side of the motor 16. The brake 18 is arranged between the motor 16 and the reduction gear 22. The specific structure of the brake 18 will be described later.

[0030] The housing 20 is supported by a support member (not shown) disposed outside the motor device 10. The support member is, for example, the first arm of the industrial robot 12. The housing 20 includes a motor housing 32 that houses the motor 16 and a brake housing 34 that houses the brake 18. In this embodiment, the brake housing 34 is configured as part of the same component as the motor housing 32. Alternatively, the brake housing 34 may be configured as a separate member from the motor housing 32. The brake housing 34 rotatably supports the motor shaft 14 via a first bearing 36.

[0031] The reduction gear 22 reduces the speed of the motor shaft 14 and outputs the reduced speed to the driven components. The reduction gear 22 includes a reduction mechanism 38 that reduces the speed of the motor shaft 14; a housing 40 that houses the reduction mechanism 38; and an output member 42 that outputs the reduced speed of the rotational power from the reduction mechanism 38 to the driven components.

[0032] The speed reduction mechanism 38 of this embodiment is a flexural meshing speed reduction mechanism that flexes and deforms the external gear 46 meshing with the internal gear member 44, thereby rotating the external gear 46 and transmitting the rotational component to the output member 42. This speed reduction mechanism 38 itself is well known and will not be described in detail here.

[0033] The housing 40 is fixed to the brake housing 34 by bolts or the like, thereby becoming integral with the brake housing 34. The output member 42 of this embodiment is a carrier 48 disposed on the output side relative to the reduction mechanism 38. The reduction gear 22 further includes a second bearing 50 disposed between the carrier 48 and the motor shaft 14.

[0034] Next, the features related to the brake 18 will be described. Figures 2 to 4 In the following, for the sake of convenience, hatching of the brake housing 34 and the brake shoe 58 is omitted.

[0035] The brake housing 34 includes a shoe accommodating portion 52 for accommodating a brake shoe 58 (described later). The shoe accommodating portion 52 is arranged radially outward relative to the motor shaft 14. The shoe accommodating portion 52 includes an accommodating recess 54 that is recessed radially outward on the inner circumferential surface of the shoe accommodating portion 52.

[0036] In the shoe accommodating portion 52, wedge-shaped spaces 56A and 56B are formed between the brake housing 34 and the motor shaft 14. The spacing between the wedge-shaped spaces 56A and 56B is configured to narrow as it approaches one side in the circumferential direction. The "spacing of the wedge-shaped spaces" in this specification refers to the radial spacing between the brake housing 34 and the motor shaft 14. The wedge-shaped spaces 56A and 56B include: a first wedge-shaped space 56A, which is provided on one side in the circumferential direction relative to the accommodating recess 54 (the counterclockwise side in the figure); and a second wedge-shaped space 56B, which is provided on the other side in the circumferential direction relative to the accommodating recess 54 (the clockwise side in the figure).

[0037] The brake 18 includes a brake shoe 58 and a pressing mechanism 60 that presses the brake shoe 58 toward the outer periphery of the motor shaft 14 .

[0038] The brake shoe 58 of this embodiment includes a main body 62 that is pressed against the outer periphery of the motor shaft 14 and a protrusion 64 that protrudes radially outward from the main body 62. The protrusion 64 of the brake shoe 58 includes a pair of protrusions 64 that protrude from axially opposite edges of the outer periphery of the main body 62.

[0039] The main body 62 includes a braking surface 66 that is pressed against the outer circumference of the motor shaft 14 to brake the motor shaft 14. The braking surface 66 radially opposes the outer circumference of the motor shaft 14. In this embodiment, the braking surface 66 has an arc shape that matches the circular shape of the outer circumference of the motor shaft 14. Alternatively, the braking surface 66 is shaped to enable surface contact with the outer circumference of the motor shaft 14.

[0040] The main body 62 includes clamped portions 68A and 68B disposed in the wedge-shaped spaces 56A and 56B. The clamped portions 68A and 68B of this embodiment include a first clamped portion 68A disposed in the first wedge-shaped space 56A and a second clamped portion 68B disposed in the second wedge-shaped space 56B. The clamped portions 68A and 68B of this embodiment have a wedge-like shape, with their radial dimensions becoming thinner as they narrow toward the end of the wedge-shaped spaces 56A and 56B.

[0041] The clamped portions 68A and 68B include brake abutment surfaces 70A and 70B that abut the brake housing 34 during braking. The brake abutment surfaces 70A and 70B are radially opposed to the shoe accommodating portion 52 of the brake housing 34. The brake abutment surfaces 70A and 70B are respectively provided on a pair of clamped portions 68A and 68B. The brake abutment surfaces 70A and 70B are convexly curved. The brake abutment surfaces 70A and 70B include a first brake abutment surface 70A, provided on the side of the wedge-shaped spaces 56A and 56B where the gap is narrowed; and a second brake abutment surface 70B, provided on the side of the wedge-shaped spaces 56A and 56B where the gap is widened.

[0042] The shoe accommodating portion 52 of the brake housing 34 includes abutted surfaces 72A and 72B that abut the brake abutting surfaces 70A and 70B of the brake shoe 58. The abutted surfaces 72A and 72B include: a first abutted surface 72A, located on the narrowed side of the wedge-shaped spaces 56A and 56B; and a second abutted surface 72B, located on the widened side of the wedge-shaped spaces 56A and 56B. The abutted surfaces 72A and 72B have a radius of curvature greater than the radius of curvature of the curved surface of the brake abutting surfaces 70A and 70B. To meet this condition, the abutted surfaces 72A and 72B of this embodiment are planar with an infinite radius of curvature. Alternatively, to meet this condition, the abutted surfaces 72A and 72B may be concavely curved.

[0043] The brake shoe 58 has a non-braking abutment surface 74 that abuts the brake housing 34 when not in braking operation. "Non-braking operation" here refers to when the brake shoe 58 is released from braking the motor shaft 14. To meet this condition, the brake shoe 58 only needs to abut the brake housing 34 when the brake shoe 58 is at least moved in the retraction direction Db2 (described later) of the pressing member 76. The non-braking abutment surfaces 74 are provided on the pair of clamped portions 68A and 68B. They are located between the first braking abutment surface 70A and the second braking abutment surface 70B.

[0044] The non-braking abutment surface 74 is shaped so as to be in surface contact with the brake housing 34 when the brake is not in use. To satisfy this condition, the non-braking abutment surface 74 is planar and has the same planar shape as the abutted surface 72B of the brake housing 34. Furthermore, to satisfy this condition, when the abutted surface 72B is concavely curved, the non-braking abutment surface 74 may be convexly curved with the same curvature as the abutted surface 72B.

[0045] The pressing mechanism 60 includes a pressing member 76 capable of advancing and retracting relative to the motor shaft 14; a non-electrically driven portion 78 that drives the pressing member 76 in a first driving direction Da1 without using electricity; and an electrically driven portion 80 that drives the pressing member 76 in a second driving direction Da2 using electricity. At least a portion of the pressing mechanism 60 is disposed within the accommodating recess 54 of the brake housing 34. In this embodiment, the pressing member 76, the electrically driven portion 80, and the non-electrically driven portion 78 are all accommodated within the accommodating recess 54.

[0046] The pushing member 76 of this embodiment is a rod 84 of the electric drive unit 80 (described later). The pushing member 76 is arranged radially outward relative to the motor shaft 14. The brake shoe 58 is connected to the pushing member 76 via a positioning pin 82 so that it can move forward and backward along the forward and backward direction Db together with the pushing member 76. The positioning pin 82 is inserted into the pin hole 64a formed in the protrusion 64 of the brake shoe 58. The pin hole 64a is a long hole extending in the circumferential direction, which allows the brake shoe 58 to move relative to the positioning pin 82 in the circumferential direction. As a result, the brake shoe 58 is connected to the pushing member 76 via the positioning pin 82 in a manner that allows it to move circumferentially relative to the pushing member 76.

[0047] The advancing and retreating direction Db of the pressing member 76 is radial. Specifically, the advancing direction Db1 of the pressing member 76 is radially inward, and the retreating direction Db2 of the pressing member 76 is radially outward. When the pressing member 76 moves in the advancing direction Db1 relative to the motor shaft 14, it presses the brake shoe 58 toward the outer circumference of the motor shaft 14.

[0048] The first driving direction Da1 of the non-electrically driven unit 78 and the second driving direction Da2 of the electrically driven unit 80 are opposite to each other in the forward and backward direction Db. In this embodiment, the first driving direction Da1 is the forward direction Db1, and the second driving direction Da2 is the backward direction Db2.

[0049] The non-electrically driven unit 78 of this embodiment is an elastic member that drives the pressing member 76 based on the restoring force of elastic deformation. A specific example of the non-electrically driven unit 78 formed of this elastic member is a compression spring. The non-electrically driven unit 78 is disposed within an actuator housing 90 (described later) and between the actuator housing 90 and the rod 84.

[0050] The electric drive unit 80 of this embodiment is a solenoid actuator (linear actuator). It includes a rod 84 that can move forward and backward; a coil 86 that generates a magnetic force to move the rod 84; and an actuator housing 88 that supports the rod 84 and the coil 86. The actuator housing 88 includes an actuator case 90 that houses the rod 84; and a frame 92 that is disposed outside the actuator case 90 and supports the actuator case 90.

[0051] The electric drive unit 80 switches between energizing its own coil 86 under the control of a brake control unit (not shown). The brake control unit is a computer composed of a combination of hardware such as a CPU, ROM, and RAM, and software.

[0052] The non-motorized drive unit 78 applies a first driving force Fa in the forward direction Db1 (first driving direction Da1) to the pushing member 76, regardless of whether the electric drive unit 80 is energized. The electric drive unit 80 applies a second driving force Fb in the retracting direction Db2 (second driving direction Da2) to the pushing member 76 when the coil 86 of the electric drive unit 80 is energized. The first driving force Fa acts as a force to push the pushing member 76 in the forward direction Db1, while the second driving force Fb acts as a force to return the pushing member 76 in the retracting direction Db2. The second driving force Fb of the electric drive unit 80 is set to be greater than the first driving force Fa of the non-motorized drive unit 78. As a result, when the electric drive unit 80 is energized, the second driving force Fb counteracts the first driving force Fa and drives the pushing member 76 in the retracting direction Db2 (second driving direction Da2). On the other hand, when the electric drive unit 80 is in the de-energized state, the second drive force Fb is released, and the first drive force Fa drives the pressing member 76 in the forward direction Db1 (first drive direction Da1).

[0053] Next, the operation of the motor device 10 related to the brake 18 will be described.

[0054] refer to Figure 3 and Figure 6 .exist Figure 3 and Figure 6 The pushing mechanism 60 can make the brake shoe 58 in the braking position Pa (reference Figure 6 ) and brake release position Pb (reference Figure 3 ). When the brake shoe 58 is in the braking position Pa, the rotation of the motor shaft 14 is braked. When it is in the brake release position Pb, the brake on the motor shaft 14 is released. When the brake shoe 58 is in the brake release position Pb, a very small gap 96 is formed between the brake shoe 58 and the motor shaft 14. This gap 96 is, for example, 0.3 mm or less.

[0055] First, the operation when the rotation of the motor shaft 14 is braked by the brake 18 will be described. Figure 3 When braking the rotation of the motor shaft 14, the pressing mechanism 60 drives the brake shoe 58, located at the brake release position Pb, toward the forward direction Db1. To meet this condition, the pressing mechanism 60 of this embodiment de-energizes the electric drive unit 80 under the control of the brake control unit 94, thereby moving the pressing member 76 toward the forward direction Db1. This causes the brake shoe 58 and the pressing member 76 to move together in the forward direction Db1, with the pressing member 76 pressing the brake shoe 58 toward the outer circumference of the motor shaft 14.

[0056] refer to Figure 5When the brake shoe 58 is pressed against the outer circumference of the motor shaft 14, the friction between the brake shoe 58 and the motor shaft 14 causes the brake shoe 58 to move in the rotational direction Dc of the motor shaft 14 to be braked (hereinafter referred to as the braking rotational direction Dc) as the motor shaft 14 rotates. As a result, the clamped portion 68A of the brake shoe 58 on the braking rotational direction Dc side moves toward the narrowing side (counterclockwise in the figure) within the wedge-shaped space 56A where the clamped portion 68A is located.

[0057] When the brake shoe 58 moves along with the motor shaft 14, the first braking abutting surface 70A of the brake shoe 58 first abuts the brake housing 34. At this time, the first braking abutting surface 70A abuts the first abutted surface 72A of the brake housing 34. Meanwhile, the second braking abutting surface 70B of the brake shoe 58 does not abut the brake housing 34 at this time.

[0058] refer to Figure 6 Afterwards, the brake shoe 58 moves further in the braking rotation direction Dc along with the motor shaft 14. As a result, the second braking abutment surface 70B abuts the brake housing 34 after the brake housing 34 abuts the first braking abutment surface 70A. At this point, the second braking abutment surface 70B abuts the second abutted surface 72B of the brake housing 34. At this point, the first braking abutment surface 70A remains in abutment with the brake housing 34.

[0059] As a result, the brake shoe 58 is positioned at the braking position Pa, sandwiched between the motor shaft 14 and the brake housing 34. At this point, the clamped portion 68A of the brake shoe 58, located on the braking rotational direction Dc side, is sandwiched between the motor shaft 14 and the brake housing 34 within the wedge-shaped space 56A where the clamped portion 68A is located. Thus, the rotation of the motor shaft 14 can be braked by the brake shoe 58. Alternatively, during braking, the brake shoe 58 is sandwiched between the motor shaft 14 and the brake housing 34 within the wedge-shaped spaces 56A and 56B.

[0060] The pushing force applied by the pushing mechanism 60 to the brake shoe 58 is set to a magnitude that can maintain the state of pushing the brake shoe 58 toward the outer periphery of the motor shaft 14 even when the motor shaft 14 rotates at the expected maximum speed. Figure 2 ) is set to meet this condition.

[0061] Next, the operation when the brake 18 applied to the motor shaft 14 is released will be described.

[0062] When the brake on the motor shaft 14 is released, the pressing mechanism 60 drives the brake shoe 58, which is located at the braking position Pa, in the retreat direction Db2. To meet this condition, the pressing mechanism 60 of this embodiment energizes the electric drive unit 80 under the control of the brake control unit 94, thereby driving the pressing member 76 in the retreat direction Db2. The brake shoe 58 of this embodiment is connected to the pressing member 76, so it can move in the retreat direction Db2 together with the pressing member 76.

[0063] refer to Figure 7 . If the brake shoe 58 wants to move in the retreat direction Db2, the non-braking abutting surface 74 of the brake shoe 58 abuts against the abutted surfaces 72A and 72B of the brake housing 34, thereby guiding the brake shoe 58 in the opposite direction Dd of the braking rotation direction Dc (hereinafter referred to as the reverse direction Dd). The "reverse direction Dd" is the side where the interval of the wedge-shaped space 56A on the braking rotation direction Dc side in the circumferential direction becomes wider (clockwise in the figure). As a result, the brake shoe 58 moves radially outward (the retreat direction Db2) as it moves in the reverse direction Dd, thereby moving from the braking position Pa to the brake release position Pb (reference Figure 3 ).

[0064] The brake shoe 58 is held in the brake release position Pb with the second driving force Fb applied by the pressing mechanism 60. At this time, the non-braking contact surfaces 74 provided on the pair of clamped portions 68A, 68B of the brake shoe 58 are in surface contact with the contacted surfaces 72A, 72B of the brake housing 34.

[0065] Thus far, the braking-related operation of the motor shaft 14 has been described when the braking rotation direction Da of the motor shaft 14 is on one side of the circumferential direction (counterclockwise in the figure). In this case, as described above, the brake shoe 58 moves along with the motor shaft 14 toward one side of the circumferential direction. At this time, the first clamped portion 68A of the brake shoe 58 is sandwiched between the motor shaft 14 and the brake housing 34 within the first wedge-shaped space 56A, thereby braking the motor shaft 14. Alternatively, a case can be considered where the braking rotation direction Db of the motor shaft 14 is on the other side of the circumferential direction (clockwise in the figure). In this case, the brake shoe 58 moves along with the motor shaft 14 toward the other side of the circumferential direction. At this time, the second clamped portion 68B of the brake shoe 58 is sandwiched between the motor shaft 14 and the brake housing 34 within the second wedge-shaped space 56B, thereby braking the motor shaft 14. In this case, the only difference from the case where the braking rotation direction Da of the motor shaft 14 is on one side in the circumferential direction is that the movement directions of the brake shoes 58 when braking the motor shaft 14 are opposite to each other in the circumferential direction.

[0066] When the brake on the motor shaft 14 is released, the brake shoe 58 may sometimes forcefully bite into the wedge-shaped spaces 56A and 56B between the brake housing 34 and the motor shaft 14. In this case, the motor control unit 28 can be used to rotate the motor shaft 14 in the direction Dd (reverse direction Dd) opposite to the braking rotation direction Dc. This releases the bite of the brake shoe 58, making it easier for the electric drive unit 80 to move the brake shoe 58 in the retreat direction Db2.

[0067] As described above, the pressing mechanism 60 moves the brake shoe 58 together with the pressing member 76 in the forward direction Db1, thereby moving the brake shoe 58 from the brake release position Pb to the brake position Pa. On the other hand, the pressing mechanism 60 moves the pressing member 76 in the retreat direction Db2, thereby moving the brake shoe 58 from the brake position Pa to the brake release position Pb.

[0068] refer to Figure 2 . The pushing mechanism 60 of the present embodiment brakes the motor shaft 14 using the first driving force Fa based on the non-electric driving part 78 and the brake shoe 58 when the electric driving part 80 does not apply the second driving force Fb. On the other hand, the pushing mechanism 60 releases the braking of the motor shaft 14 by the brake shoe 58 when the electric driving part 80 applies the second driving force Fb. In other words, the pushing mechanism 60 can switch whether the brake shoe 58 brakes the motor shaft 14 only when power is supplied to the electric driving part 80. On the other hand, the pushing mechanism 60 cannot switch the braking of the motor shaft 14 by the brake shoe 58 when power is not supplied to the electric driving part 80, and the motor shaft 14 can be continuously braked by the brake shoe 58.

[0069] Next, the effects of the above-described motor device 10 will be described.

[0070] (A) According to the motor device of this embodiment, the pressing mechanism 60 presses the brake shoe 58 toward the outer periphery of the motor shaft 14, thereby braking the rotation of the motor shaft 14. Therefore, when braking the rotation of the motor shaft 14, a disc rotor, such as a disc brake, is not required, and the axial dimension of the brake 18 can be reduced accordingly.

[0071] In addition, since a disc rotor is not required, the cost and weight of the brake 18 can be reduced accordingly, and the inertia of the motor shaft 14 can also be reduced.

[0072] Furthermore, even when the motor shaft 14 is still rotating while being braked by the brake shoe 58, the braking force or reaction force acting on the brake shoe 58 and the like can be absorbed by elastic deformation of the brake housing 34, the motor shaft 14, the brake shoe 58, etc. Thus, localized large loads are less likely to be applied to the brake shoe 58 or its surrounding structures, resulting in excellent durability.

[0073] Furthermore, by moving the pressing member 76 forward and backward in the radial direction, the rotation of the motor shaft 14 can be braked. This eliminates the need for securing space for moving the pressing member 76 forward and backward in the axial direction X, as is required with a disc brake, and thus allows the axial dimension of the brake 18 to be reduced accordingly.

[0074] (B) During braking, the brake shoe 58 is sandwiched between the motor shaft 14 and the brake case 34 in the wedge-shaped spaces 56A and 56B. This allows a strong braking force to be applied to the motor shaft 14 as described below.

[0075] refer to Figure 6 The friction force acting on the brake shoe 58 between the brake shoe 58 and the motor shaft 14 is set to Fr [N], the pushing force applied to the brake shoe 58 by the pushing mechanism 60 (hereinafter referred to as the main pushing force) is set to Fn [N], and the dynamic friction coefficient is set to μ [-]. The relationship between them is established by the following formula (1).

[0076] Fr=μ×Fn (1)

[0077] The clamped portion 68A of the brake shoe 58 is clamped within the wedge-shaped space 56A located on the braking rotation direction Dc side. Consequently, a portion of the friction force Fr acting on the brake shoe 58 is converted into an auxiliary pressing force Fm, which pushes the brake shoe 58 toward the outer periphery of the motor shaft 14, via the shoe accommodating portion 52 (the contacted surfaces 72A and 72B) of the brake housing 34. As a result, the auxiliary pressing force Fm is present in addition to the main pressing force Fn, thereby increasing the braking force exerted by the brake shoe 58. Consequently, the brake shoe 58 can impart a strong braking force to the motor shaft 14.

[0078] The auxiliary thrust force Fm has a magnitude that is positively correlated with the friction force Fr. Similarly, as shown in formula (1), the friction force Fr also has a magnitude that is positively correlated with the main thrust force Fn. Therefore, if the main thrust force Fn is increased, the auxiliary thrust force Fm can also be effectively increased accordingly. Based on this relationship, a very strong braking force can be applied to the motor shaft 14 by the brake shoe 58. Since a strong braking force can be ensured by utilizing this auxiliary thrust force Fm, it is possible to achieve low power consumption of the electric drive unit 80 while ensuring the braking force.

[0079] In addition, the brake shoe 58 is preferably arranged vertically upward with respect to the motor shaft 14. This can increase the dynamic friction force Fr of the formula (1) corresponding to the deadweight of the brake shoe 58.

[0080] The brake shoe 58's braking abutment surfaces 70A, 70B are convexly curved, while the abutted surfaces 72A, 72B of the brake housing 34 have a larger radius of curvature than the braking abutment surfaces 70A, 70B. This reduces the contact area between the abutted surfaces 72A, 72B of the brake housing 34 and the brake abutment surfaces 70A, 70B of the brake shoe 58, compared to a situation where the curvature radii of the braking abutment surfaces 70A, 70B and the abutted surfaces 72A, 72B are the same. The smaller this contact area, the less frictional resistance applied by the brake housing 34 in the reverse direction Dd when the brake shoe 58 moves in the braking rotational direction Dc with the motor shaft 14. This makes it easier for the brake shoe 58 to firmly engage in the braking rotational direction Dc, making it easier for the brake shoe 58 to brake the motor shaft 14.

[0081] The brake shoe 58 includes a first braking contact surface 70A that first contacts the brake housing 34 and a second braking contact surface 70B that subsequently contacts the brake housing 34. Advantages thereof will now be described.

[0082] Here, consider the first braking stage (refer to Figure 5 In this case, the contact area between the brake housing 34 and the brake shoe 58 can be reduced compared to a case where the second braking contact surface 70B also contacts the brake housing 34. Therefore, during the first braking phase, the frictional resistance applied by the brake housing 34 in the reverse rotation direction Dd can be reduced. Furthermore, it is easier for the brake shoe 58 to firmly engage between the brake housing 34 and the motor shaft 14 in the braking rotation direction Dc.

[0083] Furthermore, consider the second braking stage (refer to FIG. 1 ) in which both the first braking contact surface 70A and the second braking contact surface 70B contact the brake housing 34. Figure 6 At this time, the contact area with the brake housing 34 can be increased compared to the first braking stage. This can suppress the shaking of the brake shoe 58, so that the motor shaft 14 can be braked stably by the brake shoe 58.

[0084] The non-braking abutment surface 74 is shaped so as to be in surface contact with the brake housing 34 when not in use. Thus, compared to a situation where the convexly curved braking abutment surface 70A abuts the planar abutted surface 72B of the brake housing 34, the brake shoe 58 is less likely to tilt about an imaginary line parallel to the axial direction when not in use. "Non-braking" here refers to when the pressing mechanism 60 is moving the brake shoe 58 in the retreat direction Db2 or when the pressing mechanism 60 is maintaining the brake shoe 58 in the brake release position Pb. This prevents the brake shoe 58 from contacting the motor shaft 14 due to tilting when not in use.

[0085] In particular, the non-braking abutment surfaces 74 are provided on the pair of clamped portions 68A and 68B. This allows the brake shoe 58 to come into surface contact with the brake housing 34 at two locations on either side of the circumference while the pressing mechanism 60 holds the brake shoe 58 in the brake release position Pb. This effectively prevents the brake shoe 58 from tilting.

[0086] The brake shoe 58 is connected to the pressing member 76 so as to be movable in the circumferential direction relative to the pressing member 76. This allows the brake shoe 58 to move in the circumferential direction so as to be sandwiched between the brake housing 34 and the motor shaft 14. Furthermore, a more robust mechanical structure can be achieved compared to a case where the brake shoe 58 is not connected to the pressing member 76.

[0087] (Second embodiment)

[0088] refer to Figure 8 and Figure 9 In the first embodiment, the pressing mechanism 60 has a pressing member 76 connected to the brake shoe 58 to move the brake shoe 58 from the braking position Pa to the brake release position Pb. In contrast, the pressing member 76 of this embodiment is not connected to the brake shoe 58. Furthermore, the pressing mechanism 60 of this embodiment includes biasing members 100A and 100B that bias the brake shoe 58 in the retreat direction Db2 to move the brake shoe 58 from the braking position Pa to the brake release position Pb.

[0089] The force-applying components 100A and 100B of this embodiment are tension springs, and apply force to the brake shoe 58 based on the elastic restoring force of elastic deformation. The tension springs (i.e., the force-applying components 100A and 100B) connect the brake housing 34 and the brake shoe 58. The force-applying components 100A and 100B include: a first force-applying component 100A corresponding to the first wedge-shaped space 56A; and a second force-applying component 100B corresponding to the second wedge-shaped space 56B. The first force-applying component 100A can apply force to the brake shoe 58 toward the side of the retreat direction Db2 where the gap between the first wedge-shaped space 56A is widened (clockwise in the figure). The second force-applying component 100B can apply force to the brake shoe 58 toward the side of the retreat direction Db2 where the gap between the second wedge-shaped space 56B is widened (counterclockwise in the figure).

[0090] Next, the operation of the motor device 10 will be described. Figure 9 The operation of braking the rotation of the motor shaft 14 using the brake 18 is the same as that of the first embodiment. When braking the motor shaft 14, the clamped portion 68A of the brake shoe 58 located on the braking rotation direction Dc side is sandwiched between the brake housing 34 and the motor shaft 14 within the wedge-shaped space 56A in which the clamped portion 68A is located.

[0091] Next, the action when the brake 18 releases the brake on the motor shaft 14 will be described. At this time, as in the first embodiment, the pushing mechanism 60 drives the pushing component 76 of the pushing mechanism 60 in the retreat direction Db2. In this embodiment, since the brake shoe 58 is not connected to the pushing component 76, only the pushing component 76 moves toward the retreat direction Db2, thereby releasing the push of the pushing component 76 on the brake shoe 58. Thus, the brake shoe 58 can be moved in the retreat direction Db2 by the force-applying component 100A corresponding to the wedge-shaped space 56A in which the brake shoe 58 is sandwiched. At this time, the brake shoe 58 can be moved toward the retreat direction Db2 and the side of the wedge-shaped space 56A in which the brake shoe 58 is sandwiched, where the interval is widened ( Figure 9 As a result, the brake shoe 58 can move from the braking position Pa to the brake release position Pb.

[0092] According to the motor device 10 , since the components described in (A) and (B) are included, effects corresponding to the description can also be obtained.

[0093] In addition, since the pressing member 76 is not connected to the brake shoe 58, it is possible to omit components required to connect the pressing member 76 and the brake shoe 58. Furthermore, a wide space can be ensured between the pressing member 76 and the brake shoe 58.

[0094] Here, the urging members 100A and 100B are described as elastic members such as springs. The specific examples of the urging members 100A and 100B are not particularly limited. The urging members 100A and 100B may also be magnets, for example. This assumes that the brake shoe 58 is urged by the magnetic force of the magnets.

[0095] refer to Figure 10 In the first embodiment, an example was described in which the outer circumferential surface of the motor shaft 14 was circular and the braking surface 66 of the brake shoe 58 was arc-shaped. In contrast, in this embodiment, the outer circumferential surface of the motor shaft 14 and the braking surface 66 of the brake shoe 58 are formed with a concave-convex structure 102 that meshes with each other. This concave-convex structure 102 has concave and convex portions arranged alternately in the circumferential direction. As a result, the brake shoe 58 can impart a stronger braking force to the motor shaft 14.

[0096] (Third embodiment)

[0097] refer to Figure 11 . The motor device 10 of the present embodiment is different from that of the first embodiment in that the structure of the pushing mechanism 60 is different. The non-electric drive portion 78 and the electric drive portion 80 of the pushing mechanism 60 of the present embodiment are arranged at different locations. Next, this will be described in detail. The electric drive portion 80 is accommodated in a mechanism accommodating portion 110 provided at a location of the brake housing 34 that is different from the accommodating recess 54. The direction perpendicular to the advance and retreat direction Db and the axial direction X of the pushing component 76 is referred to as the perpendicular direction De. At this time, the electric drive portion 80 is arranged at a position offset from the brake shoe 58 in the perpendicular direction De. The non-electric drive portion 78 is accommodated in the accommodating recess 54 in the same manner as in the first embodiment.

[0098] In the first embodiment, the pressing member 76 is described as the rod 84 of the electric drive unit 80. In this embodiment, the pressing member 76 is the second link member 116 of the link mechanism 112, which is different from the rod 84. This will be described in detail below.

[0099] The rod 84 is connected to the brake shoe 58 via a link mechanism 112. The link mechanism 112 includes a first link member 114 connected to the rod 84 and a second link member 116 connected to the brake shoe 58. One end of the first link member 114 is rotatably fixed to the brake housing 34 via a fixing pin 118. The other end of the first link member 114 is rotatably connected to the rod 84 via a first connecting pin 120. One end of the second link member 116 is rotatably connected to the middle portion of the first link member 114 via a second connecting pin 122. The other end of the second link member 116 is rotatably connected to the brake shoe 58 via a third connecting pin 124.

[0100] The second link member 116 constitutes the pressing member 76 . The compression spring constituting the non-electrically driven portion 78 couples the brake case 34 and the second link member 116 .

[0101] When the coil 86 of the electric drive unit 80 is energized, the second driving force Fb in the retracting direction Db2 is applied to the pressing member 76 via the link mechanism 112. As a result, similar to the first embodiment, in this state, the pressing member 76 moves in the retracting direction Db2 based on the second driving force Fb, resisting the first driving force Fa of the non-electric drive unit 78. Conversely, when the electric drive unit 80 is de-energized, similar to the first embodiment, the first driving force Fa of the non-electric drive unit 78 causes the pressing member 76 to move in the advancing direction b1.

[0102] According to the motor device 10 , since the components described in (A) and (B) are included, effects corresponding to the description can also be obtained.

[0103] In addition, by arranging the electric drive unit 80 at a location different from the accommodating recess 54 , the outer diameter of the entire brake housing 34 can be reduced.

[0104] (Fourth embodiment)

[0105] refer to Figure 12 and Figure 13 The motor device 10 of this embodiment differs from the first embodiment in the structures of the pressing member 76 and the brake shoe 58. The pressing member 76 of this embodiment is provided separately from the rod 84 and is attached to the end of the rod 84 on the side in the forward direction Db1.

[0106] The brake shoe 58 is composed of rollers 130A and 130B. The rollers 130A and 130B (brake shoe 58) include a first roller 130A rotatably disposed in the first wedge-shaped space 56A and a second roller 130B rotatably disposed in the second wedge-shaped space 56B. The rollers 130A and 130B are cylindrical bodies extending in the axial direction X.

[0107] Next, the operation of the motor device 10 will be described. First, the operation when the rotation of the motor shaft 14 is braked by the brake 18 will be described. Figure 13. When braking the rotation of the motor shaft 14, the pushing mechanism 60 moves the pushing member 76 toward the forward direction Db1, thereby pushing the rollers 130A and 130B toward the outer periphery of the motor shaft 14 through the pushing member 76. If the brake shoe 58 is pushed toward the outer periphery of the motor shaft 14, the first roller 130A located on the braking rotation direction Dc side moves toward the braking rotation direction Dc as the motor shaft 14 rotates. At this time, the first roller 130A moves toward the side where the gap narrows (counterclockwise in the figure) in the first wedge-shaped space 56A. The movement of the first roller 130A toward the side where the gap widens in the wedge-shaped space 56A is restricted by the pushing member 76. As a result, the first roller 130A is sandwiched between the motor shaft 14 and the brake housing 34 in the first wedge-shaped space 56A. The rotation of the motor shaft 14 can be braked by the first roller 130A.

[0108] Meanwhile, the second roller 130B located in the reverse rotation direction Dd tends to move toward the braking rotation direction Dc as the motor shaft 14 rotates. At this point, the second roller 130B tends to move toward the wider spacing (counterclockwise in the figure) within the second wedge-shaped space 56B. The movement of the second roller 130B is restricted by the pressing member 76. As a result, the second roller 130B continues to rotate within the second wedge-shaped space 56B without becoming trapped between the motor shaft 14 and the brake housing 34.

[0109] Next, the operation when the brake 18 is released from the motor shaft 14 will be described. Figure 12 . When releasing the brake on the motor shaft 14, the pushing mechanism 60 moves the pushing member 76 toward the retreat direction Db2. As a result, the pushing of the rollers 130A and 130B by the pushing member 76 is released. As a result, the rollers 130A and 130B are allowed to move toward the side where the gap is wider within the wedge-shaped spaces 56A and 56B. Thus, even if the rollers 130A and 130B want to move as the motor shaft 14 rotates, they can move toward the side where the gap is wider within the wedge-shaped spaces 56A and 56B, thereby avoiding the situation where the motor shaft 14 is braked. As a result, the brake on the motor shaft 14 by the rollers 130A and 130B can be released.

[0110] According to the motor device 10 , since the components described in (A) and (B) are included, effects corresponding to the description can also be obtained.

[0111] Next, other modified examples of each component will be described.

[0112] The application of the motor device 10 is not particularly limited. For example, the motor device 10 can be used in an industrial robot 12 as well as an automated transport vehicle such as an AGV. When the motor device 10 is used in an industrial robot 12, it can also be used in other industrial robots 12 besides collaborative robots. Specific examples of driven components to which the rotational power of the motor device 10 is transmitted are not particularly limited.

[0113] The motor device 10 does not necessarily require the reduction gear 22. In other words, the motor shaft 14 may directly transmit the rotational power to the driven member.

[0114] The specific example of the reduction mechanism 38 used in the reduction gear 22 is not particularly limited. In addition to a flexure meshing reduction gear, the reduction gear 38 may also use, for example, an eccentric oscillating reduction gear, a planetary gear mechanism, an orthogonal gear mechanism, a parallel gear mechanism, or the like. When a flexure meshing reduction gear is used, its specific example is not particularly limited. In addition to a cylindrical flexure meshing reduction gear, a cup-shaped or top-hat flexure meshing reduction gear may be used. The output member 42 of the reduction gear 22 may be the housing 40 in addition to the wheel carrier 48.

[0115] The arrangement position of the brake 18 is not particularly limited. For example, the brake 18 may be arranged on the opposite side of the motor 16 from the output side.

[0116] The specific example of the pressing mechanism 60 is not particularly limited. For example, the second driving direction Da2 of the electric drive unit 80 may be the forward direction Db1, and the first driving direction Da1 of the non-electric drive unit 78 may be the retracting direction Db2. In this case, when no power is supplied to the electric drive unit 80, the brake shoe 58 remains in the released state from braking the motor shaft 14.

[0117] The shapes of the brake contact surfaces 70A, 70B of the brake shoe 58 and the shapes of the contacted surfaces 72A, 72B of the brake housing 34 are not particularly limited. For example, the brake contact surfaces 70A, 70B and the contacted surfaces 72A, 72B may be curved surfaces having the same radius of curvature. The brake shoe 58 may also not have the first brake contact surface 70A and the second brake contact surface 70B that contact the brake housing 34 at different times. That is, when the brake shoe 58 moves along the motor shaft 14 toward the braking rotation direction Dc, once the brake contact surfaces 70A, 70B of the brake shoe 58 contact the brake housing 34, there is no need to add additional contact areas.

[0118] The non-braking abutment surface 74 of the brake shoe 58 does not need to be shaped so as to be in surface contact with the brake housing 34 when not in braking operation. Alternatively, the non-braking abutment surface 74 shaped so as to be in surface contact with the brake housing 34 when not in braking operation may be provided on only one of the clamped portions 68A, 68B. Furthermore, the non-braking abutment surface 74 may be provided on the side of the first braking abutment surface 70A where the gap between the wedge-shaped spaces 56A, 56B is narrower, or on the side of the second braking abutment surface 70B where the gap between the wedge-shaped spaces 56A, 56B is wider.

[0119] The specific mechanism for connecting the brake shoe 58 to the pressing member 76 so as to be movable in the circumferential direction relative to the pressing member 76 is not particularly limited. For example, the brake shoe 58 may be connected to the pressing member 76 so as to be movable relative to the pressing member 76 via a sliding mechanism.

[0120] The above embodiments and variations are merely examples. The technical ideas that abstract these should not be interpreted as being limited to the contents of the embodiments and variations. The contents of the embodiments and variations can undergo various design changes, such as changes, additions, deletions, etc. of constituent elements. In the above embodiments, the contents that can undergo such design changes are emphasized by marking "embodiment". However, design changes are also allowed for contents without such markings. The hatching marked in the cross-section of the accompanying drawings does not limit the material of the objects marked with the hatching.

[0121] Any combination of the above components is also effective. For example, any content of other embodiments may be combined with an embodiment, and any content of an embodiment and other modifications may be combined with a modification.

[0122] Next, a specific example will be described. For example, the braking contact surfaces 70A, 70B and the non-braking contact surface 74 of the brake shoe 58 described in the first embodiment may be applied to the brake shoe 58 described in the second and third embodiments. The concave-convex structure 102 described in the second embodiment may also be applied to the brake shoe 58 described in the first and third embodiments.

Claims

1. A motor device comprising: a motor to rotate a motor shaft; a brake for braking the rotation of the motor shaft; and a brake housing, accommodating the brake, The motor device is characterized in that The brake has: brake shoes; and a pressing mechanism for pressing the brake shoe toward the outer periphery of the motor shaft, When the pushing mechanism pushes the brake shoe toward the outer periphery of the motor shaft, the brake shoe moves in the rotation direction of the motor shaft as the motor shaft rotates, and the brake shoe is clamped between the motor shaft and the brake housing, thereby braking the rotation of the motor shaft. The pressing mechanism includes a pressing member that can move forward and backward relative to the motor shaft. The brake shoe is connected to the pressing member so as to be movable in the circumferential direction relative to the pressing member.

2. The motor device according to claim 1, wherein: A wedge-shaped space is formed between the brake housing and the motor shaft. During braking, the brake shoe is sandwiched between the motor shaft and the brake housing in the wedge-shaped space.

3. The motor device according to claim 1, wherein: The brake shoe has a braking contact surface that contacts the contacted surface of the brake housing during braking. The braking contact surface is a convex curved surface. The abutted surface has a shape having a curvature radius larger than a curvature radius of the curved surface of the braking abutting surface.

4. A motor device comprising: a motor to rotate a motor shaft; a brake for braking the rotation of the motor shaft; and a brake housing, accommodating the brake, The motor device is characterized in that The brake has: brake shoes; and a pressing mechanism for pressing the brake shoe toward the outer periphery of the motor shaft, When the pushing mechanism pushes the brake shoe toward the outer periphery of the motor shaft, the brake shoe moves in the rotation direction of the motor shaft as the motor shaft rotates, and the brake shoe is clamped between the motor shaft and the brake housing, thereby braking the rotation of the motor shaft. The brake shoe has a braking contact surface that contacts the contacted surface of the brake housing during braking. The braking contact surface is a convex curved surface. The abutted surface has a curvature radius greater than the curvature radius of the curved surface of the braking abutting surface. The braking contact surface comprises: a first brake abutting surface that first abuts against the brake housing when the brake shoe moves in the rotation direction of the motor shaft as the motor shaft rotates; and The second brake contact surface comes into contact with the brake case after the first brake contact surface comes into contact with the brake case.

5. The motor device according to claim 3 or 4, characterized in that: The brake shoe has a non-braking contact surface that contacts the brake housing when not braking. The non-braking contact surface is shaped so as to be in contact with the brake housing surface when the brake is not in use.

6. The motor device according to claim 5, characterized in that The brake shoe has: a first clamped portion that is clamped between the motor shaft and the brake housing when the brake shoe moves toward one side in the circumferential direction; and The second clamped portion is clamped between the motor shaft and the brake housing when the brake shoe moves toward the other side in the circumferential direction. The non-braking abutting surfaces are respectively provided on the first clamped portion and the second clamped portion.

7. The motor device according to claim 4, characterized in that The brake shoe has a non-braking contact surface that contacts the brake housing when not braking. The non-braking abutment surface is provided between the first braking abutment surface and the second braking abutment surface, and has a shape capable of making surface contact with the brake housing when the brake is not in operation.

8. The motor device according to claim 4 or 7, characterized in that: The pushing mechanism comprises: a pressing member capable of moving forward and backward relative to the motor shaft and capable of pressing the brake shoe toward the outer periphery of the motor shaft when moving in a forward direction; and A force applying member applies force to the brake shoe in the retreat direction of the pressing member. The pressing member is not connected to the brake shoe.

9. The motor device according to claim 4 or 7, characterized in that: The brake shoe is composed of rollers.

10. The motor device according to any one of claims 1 to 4, characterized in that: A reduction gear is further provided for reducing the speed of the rotation of the motor shaft. The brake is disposed between the motor and the reduction gear.

11. The motor device according to any one of claims 1 to 4, characterized in that: The motor device is assembled in the joint part of the industrial robot.

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