DE102021118865A1 - MOTOR DEVICE - Google Patents

Abstract

A technique capable of reducing an axial dimension of a brake (18) is to be provided. A motor device (10) is provided which includes a motor (16), a brake (18) which brakes rotation of a motor shaft (14) and a brake housing (34) which houses the brake (18). The brake (18) includes a brake shoe (58) and a pressing mechanism (60) for pressing the brake shoe (58) toward an outer periphery of the motor shaft (14). When the brake shoe (58) is pressed toward the outer periphery of the motor shaft (14) by the pressing mechanism (60), the brake shoe (58) moves together with the motor shaft (14) in a direction of rotation of the motor shaft (14), and the brake shoe (58) is clamped between the motor shaft (14) and the brake housing (34) so that the rotation of the motor shaft (14) is braked.

Description

BACKGROUND OF THE INVENTION

field of invention

The present disclosure relates to a motor device.

Description of the prior art

Japanese Unexamined Patent Publication No. H10-225064 discloses a motor device incorporating a disk brake as a brake. In general, the disc brake includes a brake rotor that rotates with a motor shaft and a brake shoe for braking the motor shaft by pressing it against the brake rotor.

SUMMARY OF THE INVENTION

When a disk brake is used as a brake, a brake rotor must be arranged in an axial direction with respect to a brake shoe to brake rotation of a motor shaft. Therefore, an axial dimension of the brake as a whole tends to increase. The inventor of the present application has recognized that there is room for improvement in the prior art from a viewpoint of reducing the axial dimension of the brake.

An object of the present disclosure is to provide a technique capable of reducing an axial dimension of a brake.

According to an aspect of the present disclosure, there is provided a motor device that includes a motor that rotates a motor shaft, a brake that brakes rotation of the motor shaft, and a brake case that houses the brake. The brake includes a brake shoe and a pressing mechanism for pressing the brake shoe toward an outer periphery of the motor shaft. When the brake shoe is pressed toward the outer periphery of the motor shaft by the pressing mechanism, the brake shoe moves together with the motor shaft in a direction of rotation of the motor shaft, and the brake shoe is clamped between the motor shaft and the brake housing, so that the rotation of the motor shaft is braked.

According to the aspect of the present disclosure, an axial dimension of the brake can be reduced.

character list

• 1 12 is a side sectional view of a motor device according to a first embodiment.
• 2 13 is a view showing a portion of a cross section taken along line AA in FIG 1 represents.
• 3 is an enlarged view of 2 .
• 4 14 is a perspective view of a brake shoe according to the first embodiment.
• 5 12 is an enlarged view showing an intermediate state in which the brake shoe moves from a brake release position to a brake position in the power device according to the first embodiment.
• 6 14 is an enlarged view showing a state where the brake shoe is at the braking position in the power device according to the first embodiment.
• 7 14 is an enlarged view showing an intermediate state in which the brake shoe moves from the braking position to the brake releasing position in the power device according to the first embodiment.
• 8th 12 is a schematic view showing a state where the brake shoe is at the brake release position in a power device according to a second embodiment.
• 9 12 is a schematic view showing a state where the brake shoe is at the braking position in the power device according to the second embodiment.
• 10 Fig. 14 is an enlarged view from an area A in 9 .
• 11 12 is a schematic view when a motor device according to a third embodiment is viewed from the same angle as in FIG 3 is looked at.
• 12 12 is a schematic view showing a state in which braking performed by the brake shoe is released in a power device according to a fourth embodiment.
• 13 12 is a schematic view showing a state in which braking performed by the brake shoe is performed in the power device according to the fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments are described below. The same reference numerals are assigned to the same components, and repeated description is omitted. In each drawing, components are appropriately omitted, enlarged, or reduced for convenience of description. The drawings are to be viewed in accordance with a direction of the reference numerals.

(First embodiment)

With reference to 1 a first embodiment will be described. A motor device 10 according to the present embodiment is installed in a wrist portion 12a of an industrial robot 12 . The industrial robot 12 according to the present embodiment is a cooperative robot that performs work in cooperation with a person.

The motor device 10 according to the present embodiment mainly includes a motor shaft 14, a motor 16, a brake 18, a housing 20 and a speed reducer 22.

Motor shaft 14 is used to transmit rotary power generated by motor 16 to a driven member (not shown). The driven member according to the present embodiment is a second arm connected to a first arm of the industrial robot 12 via the wrist portion 12a. Hereinafter, a direction extending along a rotation centerline CL of the motor shaft 14 is referred to as an axial direction X, and a circumferential direction and a radial direction of a circle formed around the rotation centerline CL are referred to as a "circumferential direction" and a "radial direction," respectively " designated. In addition, a side in the axial direction X (left side in 1 ) is referred to as an output side, and the other side in the axial direction X (right side in 1 ) is referred to as an opposite output side.

The motor 16 can rotate the motor shaft 14 . The motor 16 includes a stator 24 fixed to a motor case 32 (described later), and a rotor 26 rotated integrally with the motor shaft 14. As shown in FIG. The motor 16 according to the present embodiment is a servomotor and includes a motor control unit 28 such as a motor driver for controlling rotation of the motor 16, and a phase detector 30 such as an encoder for detecting a rotational phase of the motor shaft 14.

The brake 18 can brake the rotation of the motor shaft 14 . The brake 18 is arranged on the output side with respect to the motor 16 . The brake 18 is positioned between the motor 16 and the speed reducer 22 . Details of the brake 18 will be described later.

The housing 20 is supported by a support member (not shown) arranged outside of the engine device 10 . The support member is, for example, the first arm of the industrial robot 12. The housing 20 includes a motor housing 32 accommodating the motor 16 and a brake housing 34 accommodating the brake 18. The brake case 34 according to the present embodiment is configured to include some of the same elements as those of the motor case 32 . Alternatively, the brake housing 34 can be separate from the motor housing 32 . The brake case 34 supports the motor shaft 14 to be rotatable via the first bearing 36 .

The speed reducer 22 slows the rotation of the motor shaft 14 and then outputs the slowed rotation to a driven element. The speed reducer 22 includes a reduction mechanism 38 that slows the rotation of the motor shaft 14, a housing 40 that houses the reduction mechanism 38, and a driven member 42 that outputs the rotational power slowed by the reduction mechanism 38 to the driven member.

The reduction mechanism 38 according to the present embodiment is a bending engagement type reduction mechanism that rotates an external gear 46 meshing with an inner member 44 by bending and deforming and moving the external gear 46 so that an axial rotational component is transmitted to the output member 42 . This type of reduction mechanism 38 itself is known, and thus description thereof will be briefly described here.

The housing 40 is fixed to the brake housing 34 using a screw that is integrated into the brake housing 34 . The driven member 42 according to the present embodiment is a carrier 48 disposed on the output side with respect to the reduction mechanism 38 . The speed reducer 22 includes a second bearing 50 disposed between the carrier 48 and the motor shaft 14 .

Features related to the brake 18 are described below. Regarding 2 until 4 the features are described. Hereinafter, hatching of the brake housing 34 and a brake shoe 58 is omitted for the sake of convenience of description.

The brake housing 34 includes a shoe housing assembly 52 for receiving the brake shoe 58 (described later). The shoe housing unit 52 is provided outside of the motor shaft 14 in the radial direction. The shoe housing unit 52 includes a housing recess portion 54 provided so as to be recessed on an inner peripheral surface of the shoe housing unit 52 outward in the radial direction.

Wedge-shaped spaces 56A and 56B are formed in shoe housing assembly 52 between brake housing 34 and motor shaft 14 . A gap between the wedge-shaped spaces 56A and 56B is provided so as to narrow toward one side in the circumferential direction. The "gap between wedge-shaped spaces" described in the present specification refers to a gap in the radial direction between the brake housing 34 and the motor shaft 14. The wedge-shaped spaces 56A and 56B include the first wedge-shaped space 56A, which is on one side in the circumferential direction in with respect to the housing recessed portion 54 (counterclockwise in the drawing) and the second wedge-shaped space 56B provided on the other side in the circumferential direction with respect to the housing recessed portion 54 (clockwise in the drawing).

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

The brake shoe 58 according to the present embodiment includes a main body portion 62 that is pressed toward the outer periphery of the motor shaft 14 and a protrusion portion 64 that protrudes outward from the main body portion 62 in the radial direction. The brake shoe 58 includes, as the protrusion portion 64, a pair of protrusion portions 64 protruding from edge portions on both sides in the axial direction on an outer peripheral surface of the main body portion 62. As shown in FIG.

The main body portion 62 includes a braking surface 66 that brakes the motor shaft 14 by being pressed against the outer periphery of the motor shaft 14 . The braking surface 66 faces the outer periphery of the motor shaft 14 in the radial direction. The braking surface 66 according to the present embodiment has an arc shape along a circular shape formed by the outer peripheral surface of the motor shaft 14 . The braking surface 66 has a shape that can come into surface contact with the outer peripheral surface of the motor shaft 14 .

The main body portion 62 includes pinched portions 68A and 68B which are located in the wedge-shaped spaces 56A and 56B described above. The pinched portions 68A and 68B according to the present embodiment include the first pinched portion 68A located in the first wedge-shaped space 56A and the second pinched portion 68B located in the second wedge-shaped space 56B. The pinched portions 68A and 68B according to the present embodiment have a wedge shape whose radial dimension becomes thin toward a side where the gap in the wedge-shaped spaces 56A and 56B is narrow.

The pinched portions 68A and 68B include brake contact surfaces 70A and 70B that contact the brake housing 34 during braking. The brake contact surfaces 70A and 70B face the shoe housing unit 52 of the brake housing 34 in the radial direction. The braking contact surfaces 70A and 70B are individually provided on each of the pair of nipped portions 68A and 68B. The brake contact surfaces 70A and 70B have a convex curved surface shape. The braking contact surfaces 70A and 70B include the first braking contact surface 70A provided on the side where the gap in the wedge-shaped spaces 56A and 56B is narrow and the second braking contact surface 70B provided on a side where the gap in of the wedge-shaped spaces 56A and 56B.

The shoe housing assembly 52 of the brake housing 34 includes contact target surfaces 72A and 72B that come into contact with the brake contact surfaces 70A and 70B of the brake shoe 58 . The contact target areas 72A and 72B include the first contact target area 72A provided on the side where the gap in the wedge-shaped spaces 56A and 56B is narrow and the second contact target area 72B provided on the side where the gap in of the wedge-shaped spaces 56A and 56B. The contact target surfaces 72A and 72B have a shape with a larger radius of curvature than a curved surface formed by the braking contact surfaces 70A and 70B. In order to satisfy this condition, according to the present embodiment, the contact target surfaces 72A and 72B have a planar shape with an infinite radius of curvature. Alternatively, to meet this condition, the contact target surfaces 72A and 72B may have a concave curved surface shape.

The brake shoe 58 includes a non-braking contact surface 74 that contacts the brake housing 34 during non-braking. Here, the “non-braking” refers to a time when the motor shaft 14 is braked by the brake jaw 58 is released. In order to satisfy this condition, the brake shoe 58 can be in contact with the brake housing 34 at least when the brake shoe 58 is moved in a backward direction Db2 (described later) of a pressing member 76 . The non-braking contact surface 74 is provided on each of the pair of pinched portions 68A and 68B. The non-braking contact surface 74 is provided between the first brake contact surface 70A and the second brake contact surface 70B.

The non-braking contact surface 74 has a shape that can make surface contact with the brake housing 34 during non-braking. In order to satisfy this condition, the non-braking contact surface 74 has a planar shape like the contact target surface 72B of the brake case 34 . Alternatively, to meet this condition, when the contact target surface 72B has a concave curved surface shape, the non-braking contact surface 74 may have a convex curved surface shape having the same curvature as the curved surface formed by the contact target surface 72B.

The printing mechanism 60 includes the printing member 76, which can reciprocate with respect to the motor shaft 14, a non-electric drive unit 78, which drives the printing member 76 in a first driving direction Da1 without using electrical energy, and an electric drive unit 80, which Pressure element 76 drives in a second drive direction Da2 with electrical energy. At least a portion of the pressure mechanism 60 is disposed within the housing recessed portion 54 of the brake housing 34 . In the present embodiment, the entirety of the pressing member 76, the electric drive unit 80 and the non-electric drive unit 78 are housed in the housing recess portion 54. As shown in FIG.

The pressing member 76 according to the present embodiment is a rod 84 (described later) of the electric drive unit 80. The pressing member 76 is arranged outside the motor shaft 14 in the radial direction. The brake shoe 58 is connected to the pressing member 76 via a positioning pin 82 so as to be able to advance and retreat together with the pressing member 76 in a fore and aft direction Db. The positioning pin 82 is inserted into a pin hole 64a formed in the boss portion 64 of the brake shoe 58. As shown in FIG. The pin hole 64a is an elongated hole that extends in the circumferential direction and allows the brake shoe 58 to move in the circumferential direction with respect to the positioning pin 82 . In this way, the brake shoe 58 is connected to the pressing member 76 via the positioning pin 82 to be movable in the circumferential direction.

The back and forth direction Db of the pressing member 76 is the radial direction. Specifically, a forward direction Db1 of the pressing member 76 is directed inward in the radial direction, and a backward direction Db2 of the pressing member 76 is directed outward in the radial direction. When moving in the forward direction Db1 with respect to the motor shaft 14 , the pressing member 76 can press the brake shoe 58 toward the outer periphery of the motor shaft 14 .

The first driving direction Da1 of the non-electric driving unit 78 and the second driving direction Da2 of the electric driving unit 80 are opposite to each other in the front and rear direction Db. In the present embodiment, the first driving direction Da1 is the forward direction Db1, and the second driving direction Da2 is the reverse direction Db2.

The non-electric driving unit 78 according to the present embodiment is an elastic member that drives the pressing member 76 using restoring force caused by elastic deformation. A specific example of the non-electric drive unit 78 configured to include the elastic member is a compression spring. The non-electric drive unit 78 is disposed between an actuator housing 90 and the rod 84 within the actuator housing 90 (described later).

The electric drive unit 80 according to the present embodiment is a solenoid actuator (linear actuator). The electric drive unit 80 includes the rod 84 that can advance and retract, 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 the actuator housing 90 that houses the rod 84 and a frame 92 that supports the actuator housing 90 while being positioned outside of the actuator housing 90 .

The electric drive unit 80 is controlled by a brake control unit (not shown) so that the energization of its own coil 86 is turned on or off. The brake control unit is a computer in which hardware such as a CPU, ROM, and RAM is combined with software.

The non-electric driving unit 78 applies a first driving force Fa in the forward direction Db1 (first driving direction Da1) to the pressing member 76, regardless of whether the electric Drive unit 80 is energized or not. When the coil 86 of the electric driving unit 80 is in an energized state, the electric driving unit 80 applies a second driving force Fb in the reverse direction Db2 (second driving direction Da2) to the pressing member 76 . The first driving force Fa functions as a force for pushing the pressing member 76 in the forward direction Db1, and the second driving force Fb functions as a force for returning the pressing member 76 in the backward direction Db2. The second driving force Fb of the electric driving unit 80 is set to be stronger than the first driving force Fa of the non-electric driving unit 78. As a result, when the electric driving unit 80 is in the energized state, the pressing member 76 is pushed in the reverse direction Db2 ( second driving direction Da2) driven by the second driving force Fb against the first driving force Fa. On the other hand, when the electric drive unit 80 is not in the energized state, the second drive force Fb is canceled, and the pressing member 76 is driven in the forward direction Db1 (first drive direction Da1) by the first drive force Fa.

An operation of the motor device 10 described above in relation to the brake 18 described above will be described.

Regarding 3 until 6 the operation is described. 3 and 6 12 represent a partially enlarged view of each drawing. The pressure mechanism 60 can move the brake shoe 58 between a braking position Pa (see FIG 6 ) and a brake release position Pb (see 3 ) move. The brake shoe 58 brakes the rotation of the motor shaft 14 when the brake shoe 58 is in the braking position Pa and releases the braking of the motor shaft 14 when the brake shoe 58 is in the brake release position Pb. When the brake shoe 58 is located at the brake releasing position Pb, an extremely small clearance 96 is formed between the brake shoe 58 and the motor shaft 14 . For example, the gap 96 has a size of 0.3 mm or less.

First, an operation in which the rotation of the motor shaft 14 is braked by the brake 18 will be described. Regarding 3 the operation is described. When the rotation of the motor shaft 14 is braked, the pressing mechanism 60 drives the brake shoe 58 located at the brake release position Pb in the forward direction Db1. In order to satisfy this condition, the printing mechanism 60 according to the present embodiment drives the printing member 76 in the forward direction Db<b>1 by de-energizing the electric drive unit 80 by a brake control unit 94 . In this way, the brake shoe 58 is moved in the forward direction Db<b>1 together with the pressing member 76 , and the pressing member 76 presses the brake shoe 58 toward the outer periphery of the motor shaft 14 .

With reference to 5 description continues. When the brake shoe 58 is pushed toward the outer periphery of the motor shaft 14, the brake shoe 58 moves due to friction between the brake shoe 58 and the motor shaft 14 along with the rotation of the motor shaft 14 in a rotating direction Dc (hereinafter referred to as a braking rotating direction Dc) of the braking motor shaft 14. In this way, the clamped portion 68A of the brake shoe 58 located in the braking rotation direction Dc moves in a direction toward a side where the gap in the wedge-shaped space 56A in which the clamped portion 68A is located is narrow (counterclockwise in the drawing).

The first brake contact surface 70A of the brake shoe 58 first contacts the brake housing 34 as the brake shoe 58 moves with the motor shaft 14 . In this case, the first brake contact surface 70A comes into contact with the first contact target surface 72A of the brake case 34. On the other hand, in this case, the second brake contact surface 70B of the brake shoe 58 does not come into contact with the brake case 34.

With reference to 6 description continues. Thereafter, the brake shoe 58 moves further with the motor shaft 14 in the braking rotation direction Dc. As a result, the second brake contact surface 70B comes into contact with the brake case 34 after the brake case 34 and the first brake contact surface 70A come into contact with each other. In this case, the second brake contact surface 70B comes into contact with the second contact target surface 72B of the brake case 34. The first brake contact surface 70A maintains a state of contact with the brake case 34.

As a result, the brake shoe 58 is located at the braking position Pa sandwiched between the motor shaft 14 and the brake case 34 . In this case, the pinched portion 68A of the brake shoe 58 located in the brake rotating direction Dc is pinched between the motor shaft 14 and the brake case 34 in the wedge-shaped space 56A in which the pinched portion 68A is located. In this way, the brake shoe 58 can brake the rotation of the motor shaft 14 . The brake shoe 58 is pinched between the motor shaft 14 and the brake housing 34 in the wedge-shaped spaces 56A and 56B during braking.

Even when the motor shaft 14 rotates at a maximum speed assumed in advance, a pressing force applied to the brake shoe 58 by the pressing mechanism 60 is adjusted to a magnitude that can maintain a state in which the brake shoe 58 is toward the outer periphery the motor shaft 14 is pushed out. In the present embodiment, the magnitude of the first driving force Fa (see 2 ) of the non-electric drive unit 78 is set to meet this condition.

Next, an operation in which the braking of the motor shaft 14 by the brake 18 is released will be described.

When the braking of the motor shaft 14 is released, the pressing mechanism 60 drives the brake shoe 58 located at the braking position Pa in the reverse direction Db2. In order to satisfy this condition, the pressing mechanism 60 according to the present embodiment drives the pressing member 76 in the backward direction Db2 so that the electric drive unit 80 is excited by the brake control unit 94 . The brake shoe 58 according to the present embodiment is connected to the pressing member 76 . Accordingly, the brake shoe 58 is moved in the backward direction Db2 together with the pressing member 76 .

With reference to 7 description continues. When the brake shoe 58 moves in the rearward direction Db2, the non-braking contact surface 74 of the brake shoe 58 comes into contact with the contact target surfaces 72A and 72B of the brake housing 34. Accordingly, the brake shoe 58 is guided in a direction Dd opposite to the braking rotating direction Dc (hereinafter referred to as a reverse rotating direction Dd). The “counter-rotational direction Dd” is directed to a side where the gap of the wedge-shaped space 56A located in the braking rotational direction Dc is wide in the circumferential direction (clockwise in the drawing). As a result, the brake shoe 58 moves outward in the radial direction (backward direction Db2) along with the movement in the counter-rotational direction Dd. In this way, the brake shoe 58 is moved from the braking position Pa to the brake releasing position Pb (see Fig 3 ).

The brake shoe 58 is held at the brake release position Pb in a state where the second driving force Fb is applied by the pressing mechanism 60 . In this case, the non-braking contact surface 74 provided in each of the pair of clamped portions 68A and 68B of the brake shoe 58 is in a state of being in surface contact with the contact target surfaces 72A and 72B of the brake housing 34.

Up to now, operational contents regarding braking of the motor shaft 14 when the braking rotating direction Da of the motor shaft 14 is directed to one side in the circumferential direction (counterclockwise in the drawing) have been described. In this case, as described above, the brake shoe 58 moves in the circumferential direction together with the motor shaft 14 to one side . In this case, the first pinched portion 68A of the brake shoe 58 is pinched between the motor shaft 14 and the brake housing 34 in the first wedge-shaped space 56A. In this way, the motor shaft 14 is braked. On the other hand, a case where the braking rotating direction Db of the motor shaft 14 is directed to the other side in the circumferential direction (clockwise in the drawing) can be considered. In this case, the brake shoe 58 moves to the other side in the circumferential direction together with the motor shaft 14 . In this case, the second pinched portion 68B of the brake shoe 58 is pinched between the motor shaft 14 and the brake housing 34 in the second wedge-shaped space 56B. In this way, the motor shaft 14 is braked. This case differs from a case where the braking rotating direction Da of the motor shaft 14 is directed to one side in the circumferential direction in that the movement of the brake shoe 58 with respect to braking the motor shaft 14 in the circumferential direction is reversed.

In some cases, when braking of the motor shaft 14 is released, the brake shoe 58 may become firmly locked to 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 rotate the motor shaft 14 in the direction Dd opposite to the braking rotating direction Dc (counter-rotating direction Dd). In this way, the locked brake shoe 58 is released, and the brake shoe 58 is slightly moved in the reverse direction Db2 by the electric drive unit 80 .

As described above, the pressing mechanism 60 can move the brake shoe 58 from the brake release position Pb to the braking position Pa by moving the brake shoe 58 together with the pressing member 76 in the forward direction Db1. On the other hand, the pressing mechanism 60 can move the brake shoe 58 from the braking position Pa to the brake releasing position Pb by moving the pressing member 76 in the retracting direction Db2.

With reference to 2 description continues. In the printing mechanism 60 according to the present embodiment, the brake shoe 58 brakes the motor shaft 14 using tion of the first driving force Fa of the non-electric driving unit 78 when the second driving force Fb is not applied by the electric driving unit 80. On the other hand, when the second driving force Fb is applied by the electric driving unit 80, the pressure mechanism 60 releases the braking of the motor shaft 14, which is being braked by the brake shoe 58. In other words, the pressure mechanism 60 can switch on or off the braking of the motor shaft 14 braked by the brake shoe 58 only when the electric power is supplied to the electric drive unit 80 . On the other hand, when the electric power is not supplied to the electric drive unit 80, the pressure mechanism 60 cannot turn on or off the braking of the motor shaft 14 braked by the brake shoe 58, and the brake shoe 58 can brake the motor shaft 14 continuously.

Advantageous effects of the engine device 10 described above will be described.

(A) According to the motor device in the present embodiment, the rotation of the motor shaft 14 can be braked by causing the pressing mechanism 60 to press the brake shoe 58 toward the outer periphery of the motor shaft 14 . Therefore, when the rotation of the motor shaft 14 is braked, a disk rotor such as a disk brake is not required, and accordingly an axial dimension of the brake 18 can be reduced.

Furthermore, since the disk rotor is not required, it is possible to achieve low cost and weight reduction of the brake 18, and further low inertia of the motor shaft 14 can be realized.

In addition, even if the motor shaft 14 is rotated in a state where the rotation of the motor shaft 14 is braked by the brake shoe 58, a braking force or reaction force acting on the brake shoe 58 may be caused by elastic deformation of the brake housing 34, the motor shaft 14 and the Brake shoe 58 are absorbed. Therefore, a large local load is less likely to act on the brake shoe 58 or a peripheral structure, and satisfactory durability can be obtained.

In addition, since the pressing member 76 is moved back and forth in the radial direction, the rotation of the motor shaft 14 can be braked. Therefore, unlike a disc brake, it is not necessary to provide a space to cause the pressing member 76 to be drawn back and forth in the axial direction X, and accordingly the axial dimension of the brake 18 can be reduced.

(B) Brake shoe 58 is pinched between motor shaft 14 and brake housing 34 in wedge-shaped spaces 56A and 56B during braking. Therefore, as will be described later, a strong braking force can be applied to the motor shaft 14.

With reference to 6 description continues. A frictional force acting on the brake shoe 58 with the motor shaft 14 is defined as Fr[N], a pressing force (hereinafter referred to as a main pressing force) exerted on the brake shoe 58 by the pressing mechanism 60 is defined as Fn [N], and a dynamic friction coefficient is defined as µ [-]. A relationship in Equation (1) below is established therebetween. $$\text{Mrs}=\mathrm{\mu }\times \text{Fn}$$

The nipped portion 68A of the brake shoe 58 is nipped in the wedge-shaped space 56A in the braking rotation direction Dc. Therefore, part of the frictional force Fr acting on the brake shoe 58 through the shoe housing unit 52 (contact target surfaces 72A and 72B) of the brake housing 34 is converted into an auxiliary pressing force Fm that presses the brake shoe 58 toward the outer periphery of the motor shaft 14 . As a result, the braking force of the brake shoe 58 can be increased by the amount of the auxiliary pressing force Fm in addition to the main pressing force Fn. In this way, the brake shoe 58 can exert a strong braking force on the motor shaft 14 .

The auxiliary pressing force Fm has a magnitude that has a positive correlation with the frictional force Fr. Similarly, as expressed in Equation (1), the frictional force Fr also has a magnitude that has a positive correlation with the main pressing force Fn. Therefore, when the main pressing force Fn is increased, the auxiliary pressing force Fm can be effectively increased accordingly. In combination with this relationship, the brake shoe 58 can apply an extremely strong braking force to the motor shaft 14 . The strong braking force can be secured using the auxiliary pressing force Fm. Therefore, the braking force can be secured, and it is possible to realize low power consumption of the electric drive unit 80 .

It is preferable that the brake shoe 58 is arranged at an upper side in a vertical direction with respect to the motor shaft 14 . In this way, the sliding friction force Fr in Equation (1) be increased by a dead weight of the brake shoe 58.

The brake contact surfaces 70A and 70B of the brake shoe 58 have a convex curved surface shape, and the contact target surfaces 72A and 72B of the brake case 34 have a shape with a larger radius of curvature than the brake contact surfaces 70A and 70B. Therefore, compared to a case where the brake contact surfaces 70A and 70B and the contact target surfaces 72A and 72B have the same radius of curvature, it is possible to reduce a contact area between the contact target surfaces 72A and 72B of the brake housing 34 and the brake contact surfaces 70A and 70B of the brake shoe 58 reduce. Since the contact area is reduced, a frictional resistance force exerted by the brake case 34 in the reverse rotation direction Dd can be reduced when the brake shoe 58 moves together with the motor shaft 14 in the brake rotation direction Dc. As a result, the brake shoe 58 is likely to be firmly locked in the braking rotating direction Dc, and the brake shoe 58 is likely to brake the motor shaft 14.

The brake shoe 58 includes the first brake contact surface 70A, which first contacts the brake housing 34, and the second brake contact surface 70B, which contacts the brake housing 34 later. This advantage will be described.

Consider a case where there is a first braking stage in which only the first braking contact surface 70A of the brake shoe 58 is in contact with the brake housing 34 (see FIG 5 ). In this case, it is possible to reduce a contact area between the brake housing 34 and the brake shoe 58 compared to a case where the second brake contact surface 70B is also in contact with the brake housing 34 . Therefore, in the first braking stage, it is possible to reduce the frictional resistance force applied from the brake case 34 in the reverse rotation direction Dd. As a result, the brake shoe 58 is likely to be firmly locked between the brake case 34 and the motor shaft 14 in the braking rotating direction Dc.

In addition, consider a case where there is a second braking stage in which the first braking contact surface 70A and the second braking contact surface 70B are in contact with the brake case 34 (see FIG 6 ). In this case, compared to a case of the first braking stage, it is possible to increase the contact area with respect to the brake case 34 . Therefore, the motor shaft 14 can be stably braked by the brake shoe 58 by suppressing the bucking of the brake shoe 58 .

The non-braking contact surface 74 has a shape that can make surface contact with the brake housing 34 during non-braking. Therefore, compared to a case where the brake contact surface 70A with a convex curved surface shape is brought into contact with the contact target surface 72B of the brake housing 34 with a flat shape, it is less likely that the brake shoe 58 during non-braking about an imaginary line parallel to the axial direction is inclined. Here, non-braking means when the pressing mechanism 60 moves the brake shoe 58 in the backward direction Db2 or when the pressing mechanism 60 holds the brake shoe 58 at the brake release position Pb. In this way, it is possible to avoid a situation where the brake shoe 58 hits the motor shaft 14 due to the inclination of the brake shoe 58 during non-braking.

In particular, the non-braking contact surface 74 is provided in each of the pair of pinched portions 68A and 68B. Therefore, when the brake shoe 58 is held at the brake release position Pb by the pressing mechanism 60, the brake shoe 58 can be brought into surface contact with the brake housing 34 at two locations on both sides in the circumferential direction. As a result, the inclination of the brake shoe 58 can be effectively prevented.

The brake shoe 58 is movably connected to the pressing member 76 in the circumferential direction. Therefore, in order to clamp the brake shoe 58 between the brake housing 34 and the motor shaft 14, it is possible to allow the brake shoe 58 to move in the circumferential direction. At the same time, compared to a case where the brake shoe 58 is not connected to the pressing member 76, a mechanically robust structure can be realized.

(Second embodiment)

With reference to 8th and 9 a second embodiment will be described. In the pressing mechanism 60 according to the first embodiment, the brake shoe 58 is moved from the braking position Pa to the brake releasing position Pb, and the pressing member 76 is connected to the brake shoe 58 . In contrast, the pressing member 76 is not connected to the brake shoe 58 according to the present embodiment. In addition, the pressing mechanism 60 according to the present embodiment includes biasing members 100A and 100B for biasing the brake shoe 58 in the backward direction Db2 to move the brake shoe 58 from the braking position Pa to the brake-release position Pb.

The biasing members 100A and 100B according to the present embodiment are extension springs and bias the brake shoes 58 using elastic restoring force caused by elastic deformation. The biasing members 100A and 100B, which are the tension springs, connect the brake housing 34 and the brake shoe 58 together. The biasing members 100A and 100B include the first biasing member 100A corresponding to the first wedge-shaped space 56A and the second biasing member 100B corresponding to the second wedge-shaped space 56B. The first biasing member 100A can bias the brake shoe 58 in the rearward direction Db2 and to a side where the gap in the first wedge-shaped space 56A is widened (clockwise in the drawing). The second biasing member 100B can bias the brake shoe 58 in the rearward direction Db2 and to a side where the gap in the second wedge-shaped space 56B is widened (counterclockwise in the drawing).

An operation of the engine device 10 described above will be described. Regarding 9 the operation is described. The operation in which the rotation of the motor shaft 14 is braked by the brake 18 is the same as in the first embodiment. When the motor shaft 14 is braked, the pinched portion 68A of the brake shoe 58 located in the braking rotation direction Dc is pinched between the brake housing 34 and the motor shaft 14 in the wedge-shaped space 56A in which the pinched portion 68A is located.

The operation in which the braking of the motor shaft 14 by the brake 18 is released will be described. In this case, as in the first embodiment, the pressing mechanism 60 drives the pressing member 76 of the pressing mechanism 60 in the reverse direction Db2. In the present embodiment, the brake shoe 58 is not connected to the pressure member 76 . Accordingly, only the pressing member 76 tends to move in the backward direction Db2, and pressing against the brake shoe 58 by the pressing member 76 is released. In this way, the brake shoe 58 is moved in the rearward direction Db2 by the biasing member 100A corresponding to the wedge-shaped space 56A in which the brake shoe 58 is pinched. In this case, the biasing member 100A moves the brake shoe 58 in the rearward direction Db2 and to a side where the gap in the wedge-shaped space 56A in which the brake shoe 58 is clamped is wide (clockwise in Fig 9 ) . As a result, the brake shoe 58 is moved from the braking position Pa to the brake releasing position Pb.

According to the engine device 10 described above, the components described in (A) and (B) above are provided. Accordingly, advantageous effects can be obtained accordingly.

In addition, the pressure element 76 is not connected to the brake shoe 58 . Accordingly, a component required for connecting the pressing member 76 and the brake shoe 58 can be omitted. As a result, a wide space between the pressing member 76 and the brake shoe 58 can be secured.

Here, an elastic member such as a spring has been described as an example of the biasing members 100A and 100B. A specific example of the biasing members 100A and 100B is not particularly limited. The biasing elements 100A and 100B may be magnets, for example. In this configuration, a case where the brake shoe 58 is biased by a magnetic force of the magnet is assumed.

With reference to 10 description continues. In the first embodiment, an example was described in which the outer peripheral surface of the motor shaft 14 has a circular shape and the braking surface 66 of the brake shoe 58 has an arc shape. In contrast, according to the present embodiment, the outer peripheral surface of the motor shaft 14 and the braking surface 66 of the brake shoe 58 have non-uniform structures 102 that engage with one another. The uneven structure 102 is a structure in which a recessed portion and a protruding portion are alternately aligned in the circumferential direction. In this way, the brake shoe 58 can apply a much greater braking force to the motor shaft 14 .

(Third embodiment)

With reference to 11 a third embodiment will be described. The motor device 10 according to the present embodiment differs from that according to the first embodiment with respect to the printing mechanism 60. The non-electric driving unit 78 and the electric driving unit 80 of the printing mechanism 60 according to the present embodiment are arranged at different locations. Details will be described. The electric drive unit 80 is housed in a mechanism housing unit 110 provided at a location other than the housing recess portion 54 of the brake case 34 . A direction perpendicular to the back and forth direction Db and the axial direction X of the pressing member 76 is taken as a perpendicular direction De designated. In this case, the electric drive unit 80 is arranged at a position deviated from the brake shoe 58 in the vertical direction De. The non-electric drive unit 78 is accommodated in the housing recess portion 54 as in the first embodiment.

An example in which the pressing member 76 according to the first embodiment is the rod 84 of the electric drive unit 80 has been described. The pressing member 76 according to the present embodiment is a second link member 116 of a link mechanism 112 different from the rod 84 . Details will be described.

The rod 84 is connected to the brake shoe 58 via the connecting mechanism 112 . The linkage mechanism 112 includes a first link 114 connected to the rod 84 and a second link 116 connected to the brake shoe 58 . An end portion of the first link member 114 is fixed to the brake case 34 so as to be rotatable via a fixing pin 118 . The other end portion of the first link member 114 is connected to the rod 84 so as to be rotatable via a first link pin 120 . An end portion of the second link 116 is connected to an intermediate portion of the first link 114 so as to be rotatable via a second link pin 122 . The other end portion of the second link member 116 is connected to the brake shoe 58 so as to be rotatable via a third link pin 124 .

The second connecting element 116 forms the pressure element 76. A compression spring forming the non-electrical drive unit 78 connects the brake housing 34 and the second connecting element 116 to one another.

When the coil 86 of the electric drive unit 80 is in an excited state, the electric drive unit 80 applies the second driving force Fb in the reverse direction Db2 to the pressing member 76 via the link mechanism 112 . As a result, in this state, as in the first embodiment, the pressing member 76 is driven by the second driving force Fb against the first driving force Fa of the non-electric driving unit 78 in the retracting direction Db2. In contrast, when the electric driving unit 80 is not in the energized state, the pressing member 76 is driven in the forward direction b1 by the first driving force Fa of the non-electric driving unit 78, as in the first embodiment.

According to the engine device 10 described above, the components described in (A) and (B) above are provided. Accordingly, advantageous effects can be obtained accordingly.

In addition, the electric drive unit 80 is arranged at a location other than that of the housing recess portion 54 . In this way, an outer diameter dimension of the entire brake case 34 can be reduced.

(Fourth embodiment)

With reference to 12 and 13 a fourth embodiment will be described. The motor device 10 according to the present embodiment differs from that according to the first embodiment with respect to the pressing member 76 and the brake shoe 58. The pressing member 76 according to the present embodiment is provided separately from the rod 84 and is at an end portion on one side in the Rod 84 forward direction Db1 attached.

Brake shoe 58 is configured to include rollers 130A and 130B. As for the rollers 130A and 130B, the brake shoe 58 includes the first roller 130A rotatably disposed in the first wedge-shaped space 56A and the second roller 130B rotatably disposed in the second wedge-shaped space 56B. The rollers 130A and 130B are circular columnar bodies extending in the X axial direction.

An operation of the engine device 10 described above will be described. First, an operation in which the rotation of the motor shaft 14 is braked by the brake 18 will be described. With reference to 13 description continues. When the rotation of the motor shaft 14 is braked, the pressing mechanism 60 moves the pressing member 76 in the forward direction Db1. In this way, the pressing member 76 presses the rollers 130A and 130B toward the outer periphery of the motor shaft 14. When the brake shoe 58 is pressed toward the outer periphery of the motor shaft 14, the first roller 130A located in the braking rotating direction Dc moves in the braking rotating direction Dc along with the rotation of the motor shaft 14. In this case, the first roller 130A moves toward a side where the gap in the first wedge-shaped space 56A is narrow (counterclockwise in the drawing). The movement of the first roller 130A to the side where the gap in the wedge-shaped space 56A is wide is restricted by the pressure member 76. As a result, the first roller 130A becomes between the motor shaft 14 and the brake case 34 in the first wedge-shaped space 56A. The rotation of the motor shaft 14 can be braked by the first roller 130A.

On the other hand, the second roller 130B, which is in the reverse rotating direction Dd, tends to move in the decelerating rotating direction Dc along with the rotation of the motor shaft 14. In this case, the second roller 130B tends to move toward a side where the gap in the second wedge-shaped space 56B is wide (counterclockwise in the drawing). The movement of the second roller 130B is restricted by the pressure element 76. FIG. As a result, the second roller 130B rotates continuously without being pinched between the motor shaft 14 and the brake housing 34 in the second wedge-shaped space 56B.

Next, an operation in which the braking of the motor shaft 14 by the brake 18 is released will be described. With reference to 12 description continues. When the braking of the motor shaft 14 is released, the pressing mechanism 60 moves the pressing member 76 in the reverse direction Db2. In this way, pressing of the pressing member 76 against the rollers 130A and 130B is released. As a result, the movement of the rollers 130A and 130B toward the side where the gap in the wedge-shaped spaces 56A and 56B is wide is allowed. Therefore, even if the rollers 130A and 130B try to move along with the rotation of the motor shaft 14, the rollers 130A and 130B can deviate to the side where the gap in the wedge-shaped spaces 56A and 56B is wide, and it is possible to avoid a situation in which the rotation of the motor shaft 14 is braked. As a result, the braking of the motor shaft 14 by the rollers 130A and 130B can be released.

According to the engine device 10 described above, the components described in (A) and (B) above are provided. Accordingly, advantageous effects can be obtained accordingly.

Other modification forms of each component will be described.

An applicable form of the engine device 10 is not particularly limited. For example, the motor device 10 may be used not only for the industrial robot 12 but also for an automatic transport vehicle such as an AGV. When the motor device 10 is used for the industrial robot 12, the motor device 10 can be used for the industrial robot 12 other than the cooperative robot. A specific example of the driven element serving as a transmission target of the rotational force of the motor device 10 is not particularly limited.

It is not essential that the engine device 10 includes the speed reducer 22 . The motor shaft 14 can transmit the rotary power directly to the driven element.

A specific example of the reduction mechanism 38 used in the speed reducer 22 is not particularly limited. For example, the reduction mechanism 38 may be an eccentric oscillating type reduction mechanism, a planetary gear mechanism, a vertical shaft gear mechanism, or a parallel shaft gear mechanism, in addition to the flexural engagement type reduction mechanism. In a case of the flexural engagement type reduction mechanism, a specific example thereof is not particularly limited. In addition to a cylindrical type, for example, a pot type or a silk hat type can be used. The output member 42 of the speed reducer 22 may be the housing 40 in addition to the carrier 48 .

A position for arranging the brake 18 is not particularly limited. For example, the brake 18 may be located on the opposite output side with respect to the motor 16 .

A specific example of the printing mechanism 60 is not particularly limited. For example, the second drive direction Da2 of the electric drive unit 80 can be the forward direction Db1 and the first drive direction Da1 of the non-electric drive unit 78 can be the reverse direction Db2. In this case, when electric power is not supplied to the electric drive unit 80, the brake shoe 58 continuously releases the braking of the motor shaft 14.

Shapes of the brake contact surfaces 70A and 70B of the brake shoe 58 and the contact target surfaces 72A and 72B of the brake case 34 are not particularly limited. For example, the braking contact surfaces 70A and 70B and the contact target surfaces 72A and 72B may have curved surface shapes having the same radius of curvature. The brake shoe 58 need not include the first brake contact surface 70A and the second brake contact surface 70B, which have different times for contacting the brake housing 34 . When the brake shoe 58 is moved together with the motor shaft 14 in the braking rotating direction Dc after the brake contact surfaces 70A and 70B of the brake shoe 58 are in contact with the brake case 34 once come, the other contact points do not have to increase.

The non-braking contact surface 74 of the brake shoe 58 need not have a shape that can make surface contact with the brake housing 34 during non-braking. Only one of the pair of pinched portions 68A and 68B may be provided with the non-braking contact surface 74 having a shape that can come in surface contact with the brake case 34 during non-braking. The non-braking contact surface 74 may be provided on a side where the gap between the wedge-shaped spaces 56A and 56B narrows with respect to the first braking contact surface 70A, or may be provided on a side where the gap between the wedge-shaped spaces 56A and 56B widens with respect to the second braking contact surface 70B.

Specific means for connecting the brake shoe 58 to the circumferentially movable pressing member 76 is not particularly limited. For example, the brake shoe 58 may be connected to the pressure member 76 so that it is movable via a sliding mechanism.

The embodiments and modification forms described above are only examples. The technical ideas that the embodiments and the modification forms abstract should not be construed as limited to the contents of the embodiments and the modification forms. Many design changes such as changes, additions, and omissions of the components can be made in the contents of the embodiments and the modification forms. In the above-described embodiments, the contents that enable the design changes are emphasized by assigning the notation of "embodiments". However, design changes are allowed even if there is no such designation. A hatched cross section in the drawing does not restrict a material of a hatched object.

Any combination between the components described above is also valid. For example, any described elements in one embodiment may be combined with those of another embodiment, or any described elements in one embodiment and other forms of modification may be combined with another form of modification.

A specific example thereof will be described. For example, each of the braking contact surfaces 70A and 70B and the non-braking contact surface 74 of the brake shoe 58 described in the first embodiment can be applied to the brake shoe 58 described in the second to third embodiments. The uneven structure 102 described in the second embodiment can be applied to the brake shoe 58 described in the first and third embodiments.

Reference List

10

engine device

12

industrial robot

12a

joint section

14

motor shaft

16

engine

18

brake

20

housing

22

speed reducer

34

brake housing

56A, 56B

wedge shaped space

58

brake shoe

60

pressure mechanism

68A, 68B

pinched section

70A

first brake contact surface

70B

second brake contact surface

72A

contact target area

74

non-braking contact surface

76

pressure element

100A, 100B

biasing element

130A, 130B

roller

Claims (12)

A motor device (10) comprising: a motor (16) rotating a motor shaft (14); a brake (18) that brakes rotation of the motor shaft (14); and a brake housing (34) accommodating the brake (18), the brake (18) including a brake shoe (58) and a pressing mechanism (60) for pressing the brake shoe (58) toward an outer periphery of the motor shaft (14), and when the brake shoe (58) is pressed toward the outer periphery of the motor shaft (14) by the pressing mechanism (60), the brake shoe (58) moves together with the motor shaft (14) in a direction of rotation of the motor shaft (14), and the Brake shoe (58) between the motor shaft (14) and the Brake housing (34) is clamped so that the rotation of the motor shaft (14) is braked. Motor device (10) after claim 1 wherein a wedge-shaped space (56A, 56B) is formed between the brake housing (34) and the motor shaft (14), and the brake shoe (58) during braking between the motor shaft (14) and the brake housing (34) in the wedge-shaped space ( 56A, 56B) is pinched. Motor device (10) after claim 1 or 2 wherein the thrust mechanism (60) includes a thrust member (76) that reciprocates with respect to the motor shaft (14), and the brake shoe (58) is movably connected to the thrust member (76) in a circumferential direction. Motor device (10) according to one of Claims 1 until 3 , wherein the brake shoe (58) includes a brake contact surface (70A, 70B) that comes into contact with a contact target surface (72A) of the brake housing (34) during braking, the brake contact surface (70A, 70B) has a convexly curved surface shape, and the contact target surface (72A) has a shape that has a larger radius of curvature than a curved surface formed by the brake contact surface (70A, 70B). Motor device (10) after claim 4 , wherein the brake contact surface (70A, 70B) includes a first brake contact surface (70A) which first contacts the brake housing (34) when the brake shoe (58) rotates together with the motor shaft (14) in the direction of rotation of the motor shaft (14 ) moves, and a second brake contact surface (70B) which comes into contact with the brake housing (34) after the first brake contact surface (70A) and the brake housing (34) come into contact with each other. Motor device (10) after claim 4 or 5 wherein the brake shoe (58) includes a non-braking contact surface (74) that contacts the brake housing (34) during non-braking, and the non-braking contact surface (74) has a shape that is in surface contact with the brake housing (34) during non-braking comes. Motor device (10) after claim 6 wherein the brake shoe (58) includes a first clamped portion (68A) which is clamped between the motor shaft (14) and the brake housing (34) when the brake shoe (58) moves in a circumferential direction to one side, and a second pinched portion (68B) pinched between the motor shaft (14) and the brake housing (34) when the brake shoe (58) moves to the other side in the circumferential direction, and the non-braking contact surface (74) in each of the first pinched portion (68A) and the second pinched portion (68B). Motor device (10) after claim 5 wherein the brake shoe (58) includes a non-braking contact surface (74) that contacts the brake housing (34) during non-braking, and the non-braking contact surface (74) is provided between the first brake contact surface (70A) and the second brake contact surface (70B). and having a shape that comes in face-to-face contact with the brake housing (34) during non-braking. Motor device (10) according to one of Claims 1 , 2 and 4 until 8th , wherein the pressure mechanism (60) includes a pressure element (76) which reciprocates with respect to the motor shaft (14) and pushes the brake shoe (58) towards the outer periphery of the motor shaft (14) when it is in a forward direction, and a biasing member (100A, 100B) biasing the brake shoe (58) in a rearward direction of the pressure member (76), and the pressure member (76) is not connected to the brake shoe (58). Motor device (10) according to one of Claims 1 , 2 and 4 until 8th wherein the brake shoe (58) is configured to include a roller (130A, 130B). Motor device (10) according to one of Claims 1 until 10 , further comprising: a speed reducer (22) that slows rotation of the motor shaft (14), the brake (18) being disposed between the motor (16) and the speed reducer (22). Motor device (10) according to one of Claims 1 until 11 wherein the motor device (10) is built into a joint portion (12a) of an industrial robot (12).

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