JPS6354141B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic brake-equipped power unit suitable for use in assembly robots and the like.

[Prior Art] In general, it is desired that a driving device mounted on an arm joint or the like of an industrial robot be small and lightweight, and capable of exerting high output torque.

Therefore, in recent years, as this type of driving device, a support member is attached to one end surface of a ring-shaped circular spline, and an open end is placed in contact with the support member, and the drive unit is disposed inside the circular spline. A harmonic reducer has a motor housing chamber formed using a thin cup-shaped flex spline that is biased by a wave generator and meshes with the circular spline, and a support shaft is fixed to the support member of the reducer. A liquid motor has been proposed that includes a liquid motor in which a casing that rotates around a support shaft is disposed within the motor housing chamber, and the wave generator is provided in the casing.

[Problems to be Solved by the Invention] However, since this device can output the power of the hydraulic motor via the harmonic reduction gear, it can generate high output torque. Moreover, since the hydraulic motor is housed within the harmonic reducer and the wave generator is integrally provided in its casing, it is possible to achieve a reduction in size and weight by effectively utilizing space and reducing the number of parts. However, if this is all there is to it, it is difficult to use it as an articulating drive source for a robot.

In other words, the driving device used in robots, etc. has a braking function to quickly and accurately stop the robot arm, etc. at a desired position against the inertial force, and to prevent the arm, etc. from running out of control during a power outage. It is desirable to have the following. However, as a measure to satisfy such a demand, for example, an armature holding a brake shoe is actuated by a spring force and an electromagnetic force to apply a brake to the casing rotating with respect to the support member, or, It is conceivable to provide an electromagnetic brake configured to be able to release the brake within the motor housing chamber. However, since a strong magnetic field is formed around the excitation coil of the electromagnetic brake,
When such an electromagnetic brake is disposed in an annular space surrounding the spindle in the motor housing chamber, the spindle of the hydraulic motor is magnetized each time the excitation coil is energized. When the spindle becomes magnetized, iron powder, etc. contained in the hydraulic fluid used to drive the hydraulic motor is attracted to the surface of the spindle and gets caught in the sliding parts, causing a seizing accident. Easy to cause inconvenience. Furthermore, there is a risk that the magnetization may extend to the harmonic reducer provided in connection with the casing of the hydraulic motor, causing a similar seizure accident to the sliding portion of the reducer.

On the other hand, harmonic gearboxes usually require lubricating oil, which leads to a corresponding reduction in the coefficient of friction (μ) of the contact surfaces of the brake shoes. Brake torque (T) is given by the pressing force (F), T=
Since it is expressed as μ・F, when μ becomes smaller, F
needs to be made larger. However, when F is increased, it becomes necessary to generate a large magnetic field when the brake is released, resulting in an increase in the size of the brake.

Therefore, it is desired to generate this magnetic field efficiently.

The present invention has been made in view of these circumstances, and an object of the present invention is to provide a prime mover with a brake that can effectively eliminate the above-mentioned disadvantages.

[Means for Solving the Problems] In order to achieve the above objects, the present invention employs the following configuration.

That is, the prime mover with a brake according to the present invention includes a support member that supports a ring-shaped circular spline, and an open end of the support member that is disposed inside the circular spline and attached to the wave generator. A harmonic reducer in which a motor housing chamber is formed using a flex spline which is biased and meshes with the circular spline, and a casing which has a support shaft fixed to a support member of the reducer and rotates around this support shaft are described above. A hydraulic motor disposed in a motor housing chamber, the casing of which is provided with the wave generator, and a casing of the hydraulic motor disposed in the motor housing chamber that is braked so as to stop relative to the support member. A prime mover comprising an electromagnetic brake for the purpose of the present invention, characterized in that a non-magnetic material for magnetic shielding is disposed between an excitation coil of the electromagnetic brake and a support shaft of the hydraulic motor. .

[Operation] With such a configuration, when the casing of the hydraulic motor rotates, the rotational power is outputted via the harmonic reduction gear.

When the electromagnetic brake is activated, the casing is braked so as to stop against the support member that supports the support shaft of the hydraulic motor.

A magnetic field is formed around the excitation coil of this electromagnetic brake when it is energized, but a non-magnetic material for magnetic shielding is provided between this excitation coil and the support shaft. It is possible to prevent the shaft from becoming magnetized. Therefore, there is no phenomenon in which iron powder or the like contained in the working fluid is attracted to the surface of the spindle or the magnetization of the spindle affects the harmonic reduction gear portion.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4.

The power of the hydraulic motor 1 is outputted via a harmonic reduction gear 2.

The hydraulic motor 1 has a support shaft 3 having an eccentric portion 3a.
and a casing 4 that is rotatable around the axis ₀₁ of the support shaft 3. The casing 4 consists of a cup-shaped main body part 4a that surrounds the eccentric part 3a of the support shaft 3, and a lid part 4b that closes the opening of the main body part 4a, and one end of the support shaft 3 is It penetrates the lid part 4 and protrudes outside the casing 4. Further, an odd number of flat portions 4c are formed on the inner periphery of the casing 4 at equiangular intervals in the circumferential direction. Then, pistons 5 are disposed inside the casing 4 at positions corresponding to the respective plane parts 4c, and the tip surfaces of these pistons 5 are supported by hydrostatic bearings 6. It is attached to the corresponding plane portion 4c via. In the hydrostatic bearing 6, the tip end surface of the piston 5 is formed into a planar shape so as to be in close contact with the flat portion 4c, and a pressure pocket 7 is formed in the tip end surface, and fluid pressure is introduced into the pressure pocket 7. It was designed to do so. Further, a cylinder block 8 is rotatably fitted to the eccentric portion 3a of the support shaft 3, and the cylinder block 8 increases the volume on the base end surface side of each piston 5 as the casing 4 rotates. It forms a space 9 that increases and decreases. More specifically, a plurality of cylinders 11 are formed radially in the cylinder block 8 at equiangular intervals in the circumferential direction. Each of the pistons 5 is attached to each of these cylinders 11...
. . . are slidably fitted together, and the base end surface of each piston 5 .
The space 9 is formed by the inner surface of the space 9. A pin 12 is projected from the end surface of the cylinder block 8, and the tip of the pin 12 is loosely fitted into a hole 13 provided in the casing 4. Therefore, the cylinder block 8 is prevented from rotating beyond a certain rotation angle with respect to the casing 4.
That is, this cylinder block 8 is adapted to rotate following the casing 4. Moreover, the axis 0 ₁ of the support shaft 3 is inside the casing 4.
divided into a first region A and a second region B, with a virtual dividing line P passing through the axis ₀₂ of the eccentric part 3a as a border,
The space 9 passing through the first region A is communicated with the first fluid flow path 14, and the space 9 passing through the second region B is connected to the second fluid flow path 15. It communicates. First fluid flow path 1
4 is for communicating the pressure pocket 16 on the first region A side provided on the outer circumferential surface of the eccentric portion 3a to a first inlet/outlet (not shown) provided at the tip of the support shaft 3; It is formed within the support shaft 3. Further, the second fluid flow path 15 is connected to the eccentric portion 3a.
Pressure pocket 1 on the second area B side provided on the outer peripheral surface of
7 to a second inlet/outlet (not shown) provided at the tip of the support shaft 3.
formed within. Furthermore, a pressure introduction path 18 is provided at the axial center of each piston 5 for introducing the fluid pressure in the corresponding space 9 into the pressure pocket 7 of the corresponding hydrostatic bearing 6.

On the other hand, the harmonic reducer 2 includes a ring-shaped circular spline 22 having inward teeth 21 on the inner periphery, and this circular spline 22.
A thin cup-shaped flexspline 24, which is disposed on the inner side of the flex spline 24 so that the axes coincide with each other, and has outward teeth 28 having the same pitch as the inward teeth 21 and a slightly smaller number on the outer periphery of the opening end. The open end of this flexspline 24 is elastically deformed into an elliptical cross-sectional shape to cause the outward teeth 23 to mesh with the internal teeth 21 at the long axis portion thereof, and to adjust the meshing positions a and b. It is equipped with a wave generator 25 that is successively moved in the circumferential direction. The circular spline 22 is a ring-shaped rigid body,
It is supported by a disk-shaped support member 26. Also,
The flexspline 24 is a cup-shaped member made of a material with good elastic deformation, and its open end is brought into contact with the inner surface of the support member 26. A storage chamber 30 is formed. In addition, an output shaft 3 is provided at the center of the bottom wall of this flexspline 24.
The proximal end of 1 is fixed. Further, the wave generator 25 has an elliptical cam 32 rotatable around the axis of the flex spline 24 fitted around the circumference of the flex spline 24 via a flexible ball bearing 33. The outer ring 33a of 33 can be elastically deformed together with the flex spline 24.

Then, the support shaft 3 of the hydraulic motor 1 is
The casing 4 of the motor 1 is fixed to the axial center of the support member 26 of the motor 1.
4, and the wave generator 25 is integrally provided in the casing 4. That is, the elliptical cam 32 is integrally formed on the outer periphery of the lid portion 4b of the casing 4.

Further, an electromagnetic brake 52 is provided in the motor housing chamber 30 for applying braking so that the casing 4 of the hydraulic motor 1 stops relative to the support member 26. The electromagnetic brake 52 includes a brake shoe 3 fixed to the end surface of the casing 4.
3, an armature 35 made of a magnetic material held non-rotatably and movably in the axial direction by the support member 26 via a plurality of guide pins 34, and the brake shoe 33 of this armature 35. a lining 36 attached to a surface facing the casing 4; and a plurality of braking devices for applying braking to the casing 4 by pressing the lining 36 against the brake shoe 33 by urging the armature 35 in the direction of the casing 4. The armature 35 is supported by the spring 37 and the support member 26.
The armature 3 is placed on the back side of the armature 3 when energized.
5 in a direction away from the armature 4 against the biasing force of the spring 37, thereby separating the lining 35 from the brake shoe 33. be. A non-magnetic material is disposed around the excitation coil 38 to strengthen the magnetic flux to the armature 35. Specifically, a ring 39 made of stainless steel, which is a non-magnetic material, is interposed between the support member 26 made of a magnetic material such as iron and the circular spline 22,
When the excitation coil 38 is energized, the coil 3
8 is configured so that the magnetic flux generated around the support member 26 does not go around to the circular spline 22 side.

Further, the excitation coil 38 of the electromagnetic brake 52
A non-magnetic material for magnetic shielding is disposed between the hydraulic motor 1 and the support shaft 3 of the hydraulic motor 1. Specifically, a bush 41 made of stainless steel, which is a non-magnetic material, is fixed to the center of the support member 26, and the support shaft 3 is fitted into the shaft hole 41a of the bush 41 and fixed with a key 42. ing.

Note that 43 is a magnetic rotation detector, and this detector 43 is used to detect the rotational position and rotational speed of the casing 4 with respect to the support shaft 3.

Next, the operation of this prime mover will be explained. First, when a high-pressure fluid is supplied into the spaces 9, 9 existing in the first area A through, for example, the first fluid distribution system path 14, the hydrostatic pressure bearings 6, 6 existing in the first area A are high. Fluid pressures are introduced, and these fluid pressures cause forces Fa and Fb to act on the casing 4 of the hydraulic motor 1 through the axis ₀₂ of the eccentric portion 3a and perpendicular to the plane portion 4c of the casing 4. become. Therefore, the resultant force of these forces Fa and Fb
The line of action of Fab passes through the axis 0 ₂ and is deviated by a certain distance l from the axis 0 ₁ of the support shaft 3, which is the center of rotation of the casing 4 (see FIG. 4). As a result, a moment of Fab×l acts on the casing 4, thereby causing the casing 4 to rotate in the direction of arrow X. in this case,
The volumes of the spaces 9, 9 existing in the first region A gradually increase as the casing 4 rotates, and the volumes of the spaces 9, 9 existing in the second region B gradually decrease. The fluid that has completed its work flows sequentially into the spaces 9, 9 passing through the first region A through the first fluid distribution system path 14, and then flows into the second fluid from the spaces 9, 9 passing through the second region B. It is sequentially discharged to the outside through the circulation path 15. In this way, when the casing 4 of the hydraulic motor 1 rotates, for example, in the direction of the arrow X, the wave generator 2
The oval cam 32 of No. 5 similarly rotates in the direction of the arrow X,
The meshing positions a and b between the outward teeth 23 of the flex spline 24 and the inward teeth 21 of the circular spline 22 move in the direction of the arrow X. Then, each time the elliptical cam 32 rotates once, the flexspline 24 rotates in the direction of arrow Y by the difference in the number of teeth between the inward teeth 21 and the outward teeth 23, and this rotation is the output. It is taken out of the housing 28 via the shaft 31. With such a device, a desired rotational force can be applied to the output shaft 31 by controlling the direction and flow rate of the pressure fluid supplied to the first and second fluid circulation paths 14 and 15. It can be taken out from.

In the above, the excitation coil 38 of the electromagnetic brake 52 is energized to attract the armature 35 toward the coil 38 and the lining 36 to the brake shoe 33.
In this case, when the coil 38 is turned off from this state, the armature 35 is moved away from the casing 4 by the force of the spring 37.
The lining 35 is moved to the side, and the lining 35 is pressed against the brake shoe 33, thereby applying braking to the casing 4. In this way, the electromagnetic brake 52 can be switched to a braking state or a non-braking state by disconnecting the current to the excitation coil 38. However, in this device, the excitation coil 38 and Since a bush 41 made of a non-magnetic material for magnetic shielding is disposed between the support shaft 3 of the hydraulic motor 1, even when the excitation coil 38 is energized, the support shaft 3 is never magnetized. Therefore, iron powder, etc. contained in the hydraulic fluid for driving the front air hydraulic motor 1 may be adsorbed onto the surface of the spindle 3 and get caught in the sliding parts, causing a seizing accident. The same problem of seizure as described above does not occur even in the sliding parts of the harmonic reducer 2 provided in relation to the casing 4 of the motor 1.

Note that the hydraulic motor is not limited to the illustrated embodiment, and can be modified in various ways without departing from the spirit of the present invention.

Furthermore, the non-magnetic material for magnetic shielding disposed between the excitation coil and the spindle is of course not limited to that of the above embodiment, and may be made of brass or other non-ferrous metal, for example. It may be.

[Effects of the Invention] As explained above, the present invention enables the power of the hydraulic motor to be outputted via the harmonic reduction gear, so it is possible to generate high torque, and moreover, the power of the hydraulic motor can be outputted via the harmonic reduction gear. The hydraulic motor is housed in the motor housing chamber formed inside the machine, and the wave generator is integrated into the casing, making it possible to reduce the size and weight by effectively utilizing space and reducing the number of parts. It is. Furthermore, an electromagnetic brake is disposed within the motor housing chamber, and this brake can apply braking to the casing of the hydraulic motor, so that the robot arm, etc. connected to the output shaft can resist inertial force. It is possible to quickly and accurately stop the arm at a desired position, and to effectively prevent the arm and the like from running out of control during a power outage. Furthermore, since a non-magnetic material for magnetic shielding is provided between the excitation coil of the magnetic brake and the support shaft of the hydraulic motor, the magnetization of the hydraulic motor caused by magnetization of the support shaft or This can effectively prevent seizure accidents in the harmonic reducer section. Further, with such a brake, it is possible to efficiently generate a magnetic field for attracting the armature, so that the brake can be made smaller.

Further, if the hydraulic motor is configured as shown in the illustrated embodiment, it becomes particularly suitable for use in an intelligent robot that performs assembly work or the like. In other words, since the hydraulic motor of the above embodiment does not have a tilting moment acting on the piston, it is possible to maintain high mechanical efficiency even when the inlet and outlet pressures are both high pressures and the difference between them is small, and matching with the servo valve is easy. It is in very good condition. Similarly, since no tilting moment is applied to the piston, an appropriate hydraulic pressure balance is obtained between the eccentric part of the support shaft and the cylinder block for the purpose of sealing, ensuring high volumetric efficiency even at low speeds. Ru. In addition, the main components of this hydraulic motor 1 are arranged almost balanced with respect to the center of rotation, and unlike other types of hydraulic motors, there is no rotation of an eccentric shaft. High speed rotation is also possible. Therefore, the rotation speed can be varied over a wide range. Therefore, when a hydraulic motor with these characteristics is combined with a harmonic reducer that boasts high mechanical efficiency and output torque and has high positioning accuracy against twisting from the load, it is possible to create a compact and In addition to being lightweight, it has high positioning accuracy, can vary the rotational speed over a wide range, and has excellent matching with servo valves, etc.
It is possible to provide a driving device that can exhibit optimal characteristics for use in assembly robots and the like.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention, FIG. 1 is a sectional view, FIG. 2 is a schematic sectional view taken along the - line in FIG. 1, and FIG. 3 is a - in FIG. 1.
The line sectional view and FIG. 4 are action explanatory views. 1... Hydraulic motor, 2... Harmonic reducer, 4... Casing, 22... Circular spline, 24... Flex spline, 25...
Wave generator, 26...Support member, 30
...Motor accommodation chamber, 38...Excitation coil, 41...
…Non-magnetic material (stainless steel bushing),
52...Electromagnetic brake.

Claims (1)

[Claims] 1. A support member that supports a ring-shaped circular spline, and a flex that is disposed inside the circular spline with its open end in contact with the support member and that is biased by a wave generator and meshes with the circular spline. A harmonic reducer in which a motor housing chamber is formed using splines, and a casing having a support shaft fixed to a support member of the reducer and rotating around the support shaft are disposed within the motor housing chamber, and the wave is attached to the casing. A power drive comprising a hydraulic motor provided with a generator, and an electromagnetic brake disposed in the motor housing chamber for applying braking so that the casing of the hydraulic motor stops with respect to the support member. 1. A prime mover with a brake, characterized in that a non-magnetic material for magnetic shielding is disposed between an excitation coil of the electromagnetic brake and a support shaft of the hydraulic motor.