JPS6098246A - Prime mover - Google Patents

Abstract

PURPOSE:To steeply reduce the axial size of a whole device by fixing a flexible spline to a housing so as to extract the rotating power from a ring-like circular spline. CONSTITUTION:This prime mover outputs the power for a liquid-operated motor 1 via a harmonic reduction gear 2. The liquid-operated motor 1 has a support shaft 3 with an eccentric section 3a and a casing rotatable around the axis center O1 of this support shaft 3. A ring-like circular spline 22 is rotatably supported on the inner circumference of a cup-like housing, and a wave generator 25 is arranged inside this circular spline. The flexible spline 24 of the harmonic reduction gear 2 is fixed to the housing holding the support shaft of the motor 1 and extracts the rotating power from the circular spline 22.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention provides a hydraulic power drive device that can be suitably used for turning or rotating parts of industrial robots and machine tools that require precise position control. It is related to.

(B) Prior Art Conventionally, as such a driving device 6, there is a system in which a hydraulic motor and a Harmoninck reducer are connected in series, and the arm of the robot can be operated by the power taken out from the output shaft of the Harmoninck reducer. Such a specially constructed morph and speed reducer is bulky, and there are certain limits to making it particularly difficult to shorten the dimension in the axial direction.

Therefore, recently, a system has been considered in which the hydraulic motor a is housed inside a harmonic reduction gear as shown in FIG. That is, the above-mentioned Harmony.

The reduction gear is constructed by disposing a cup-shaped flexspline e that can be flexibly deformed inside the circular spline d installed in the housing C, and deforming the flexspline e with a wave generator f. It is designed to be able to mesh with the circular spline d.

The support shaft g of the hydraulic motor a is fixed to the center of the end wall of the housing C, and the casing h of the motor a, which rotates around the support Mg, is disposed within the flexspline e. The wave generator f is integrally formed with the casing h.

However, in this case, the output shaft i is attached to the end face of the flexspline e which can be flexibly deformed, and the power is extracted from the output shaft i.

It is essential to provide a bearing j for supporting the output shaft i at the end of the housing C. Therefore, the effect of shortening the dimension in the axial direction could not be said to be sufficient.

(c) Purpose The present invention was developed in response to these circumstances.It is possible to significantly shorten the axial dimension, and it can be easily installed in narrow areas such as the arm joint part of the robot. This is to provide a driving device that can.

In order to achieve such an objective, the present invention not only accommodates the casing of the hydraulic motor inside the flex spline of the harmonic reducer, but also incorporates the flex spline of the harmonic reducer into a cup that holds the spindle of the motor. The present invention is characterized in that it is configured such that rotational power can be taken out from a circular spline fixed to a shaped housing and rotatably supported on the inner periphery of the housing.

(E) Example An example of the present invention will be described below with reference to FIGS. 2 to 4.

As shown in FIGS. 2 and 3, the power device according to the present invention outputs the power of a hydraulic motor 1 via a harmonic reduction gear 2. As shown in FIGS.

The hydraulic motor 1 includes a support shaft 3 having an eccentric portion 3a, and a casing 4 capable of rotating around an axis 01 of the support shaft 3. The casing 4 is fixed to the eccentricity of the support shaft 3 @l! 3
a cylindrical main body portion 4a surrounding the main body portion 4a;
and a lid part 4b that closes the opening of the casing 4. One end of the support shaft 3 is fitted through the lid part 4b and projects out of 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 flat portions 4C, and the tip surfaces of the pistons 5 are attached to the corresponding flat portions 4C via hydrostatic bearings 6. ing. The hydrostatic bearing 6 has a distal end surface of the piston 5 formed into a planar shape so as to be in close contact with the flat portion 4C, and a pressure pocket 7 is formed on the distal 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,
This silling block 8 forms a space 9 (11) on the proximal end surface side of each piston 50 whose volume increases and decreases as the casing 4 rotates.
A plurality of cylinders 11 are radially formed in the cylinder block 8 at equal angular intervals in the circumferential direction. and,
Each piston 5 is slidably fitted into each cylinder 11, and the space 9 is formed by the base end surface of each piston 5 and the inner surface of each cylinder 11. Note that a pin 12 is protruded from the end surface of the cylinder block 8, and by letting the tip end surface of the pin 12 play freely in a hole 13 provided in the casing 4, the cylinder block 8 or the casing 4 can be connected. This is done so that it does not rotate more than one foot rotation angle. In other words, the shilling block 8 rotates following the casing 4. Further, the inside of the casing 4 is divided into a first region and a second region B with an imaginary dividing line P passing through the axis 02 of the support shaft 3 as a border, and the first region
The space 9 passing through the area A is connected to the first fluid circulation path 1.
4 and a second fluid circulation path 15, which is a space 9 passing through the second region B. The first fluid circulation path 14 is a first fluid flow path provided on the outer peripheral surface of the eccentric portion 3a.
This is for communicating the pressure hole 1-16 on the area A side with a first inlet/outlet (not shown) provided at the tip of the support shaft 3, and is formed within the support shaft 3. Further, the second fluid circulation path 15 is a second fluid flow path provided on the outer circumferential surface of the eccentric portion.
This is for communicating the pressure pocket 17 on the region B side with a second inlet/outlet (not shown) provided on the tip end surface of the spindle 3, and is formed inside the spindle 3. 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 point 7 in 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 an inwardly directed A thin cup-shaped flexspline 24 having outward facing teeth 23 having the same pitch as the teeth 21 and a slightly smaller number; It is equipped with a wave generator 25 which causes the teeth 23 to mesh with the inward teeth 21 and sequentially moves the meshing positions a and b in the circumferential direction. The circular spline 22 is a ring-shaped rigid body that is held between an output disk 26 and a presser cylinder 27, and is rotatably supported on the inner periphery of a cup-shaped housing 28 via a bearing 29. The flex spline 24 is made of a material with good elastic deformation and has an end 1jJ 24a fixed to the end wall 28a of the housing 28. Further, the wave generator 25 has an elliptical cam 29 rotatable around the axis of the flex spline 24 fitted to the inner periphery of the flex spline 24 via a flexible hall bearing 30.
The outer ring 30a of the ball bearing 30 can be elastically deformed together with the flex spline 24.

Then, the support shaft 3 of the hydraulic motor 1 is fixed to the axial center of the end wall 28a of the /\Using 28, and the casing 4 of the pump 1 is disposed within the flex-spline 24, and the casing 4 is attached to the casing 4. The wave generator 25
are provided integrally. That is, this casing 4'
The elliptical cam 29 is integrally formed on the outer periphery of the main body portion 4a.

Further, an electromagnetic brake 32 is provided within the flexspline 24 to apply braking so that the casing 4 of the hydraulic motor 1 stops relative to the housing 28. The electromagnetic brake 32 includes a brake shoe 33 fixed to the end surface of the casing 4, and a magnetic armature 35 held rotatably in the housing 28 via a plurality of guide pins 34 so as to be movable in the axial direction. ,
The lining 36 attached to the surface of the armature 35 facing the brake shoe 33 and the lining 36 are pressed against the brake shoe 33 by urging the armature 35 in the direction of the casing 4 . Multiple braking springs 3 that apply braking
7, which is supported by the housing 28 and is disposed on the back side of the armature 35, and when energized, the armature 3
5 in a direction away from the casing 4 against the biasing force of the spring 37 to separate the lining 35 from the brake shoe 33.
It is equipped with the following. Note that 39 is an electromagnetic rotation detector, and this detector 39 detects 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 the first fluid flow path 14, for example, the first area A
High fluid pressure is introduced into the hydrostatic bearing 6.6 located in the hydraulic motor 1, and these fluid pressures cause the hydraulic motor 1 to pass through the axis o2 of the eccentric portion 3a to the casing 4.
Forces Fa and Fb perpendicular to the 41-plane portion 4C act on the 41-plane portion 4C. Therefore, the resultant force Fab of these forces Fa and Fb
The line of action passes through the axis 02 and is deviated by a certain distance #L from the axis 01 of the support shaft 3, which is the rotation center of the casing 4 (see FIG. 4). As a result, a moment lFabIxL acts on the casing 4, thereby causing the casing 4 to rotate in the direction of arrow X. In this case, the space 9.9 existing in the first area A is
As the casing 4 rotates, the volume gradually increases,
Since the volume of the space 9.9 existing in the second region B gradually decreases, the high-pressure fluid passes through the first body wave passage 14 and enters the space 9.9 passing through the first region A. The fluid that has flowed in and completed its work is sequentially discharged from the space 9.9 passing through the second region B to the outside through the second fluid flow path 15. In this way, when the casing 4 of the hydraulic motor l rotates, for example, in the direction of the arrow X, the elliptical cam 29 of the wave generator 30 also rotates in the direction of the arrow , meshing positions a and b of the circular spline 22 with the inward teeth 21
moves in the direction of arrow X. Then, the elliptical cam 2
9 rotates once, the circular spline 22 rotates in the direction of arrow Y by the number difference between the inward teeth 21 and the outward teeth 23, and this rotation is transmitted to the outside of the housing 28 via the output disk 26. taken out. However, if it is like this, fJSl, second fluid flow path 1
By controlling the direction and amount of pressure fluid supplied to 4.15, a desired rotational force can be applied to the rotating disk 26.
It can be taken out from.

It should be noted that the hydraulic motor is not limited to the illustrated embodiment, and may be modified in various ways without departing from the spirit of the present invention. , the following effects can be obtained.

First, the casing of the hydraulic motor is placed inside the flexspline of the harmonic reducer, and the wave gear 2 and rake are integrally formed in the casing of the motor, so the hydraulic motor and harmonic reducer can be separated. It is possible to reduce the number of parts and use space more effectively than in the case of configuring it in the body, and it is possible to meet the demands for miniaturization and lightness and flexibility.

Moreover, since the flexspline is fixed to the housing and the rotational power is extracted from the ring-shaped circular spline rotatably supported on the inner circumference of the housing, the output shaft is attached to the flexspline which can be flexibly deformed. There is no need for a bearing like in the case where the bearing is mounted. Therefore,
Coupled with the fact that the hydraulic motor is disposed within the harmonic reduction gear, the axial dimension of the entire device can be significantly shortened. Therefore, it is possible to provide an excellent driving device that can be easily placed in various narrow areas such as the arm joint of a robot.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a conventional example, FIG. 2 is a sectional view showing an embodiment of the present invention, FIG. 3 is a schematic enlarged sectional view taken along the line ■-m in FIG. The figure is an explanatory diagram of the operation of the same embodiment. l/n hydraulic motor 2...Harmonic reducer 3...Support shaft 4---Casing 22/Circular e-spline 2401 Flex spline 25...Wave generator 28-φ/Housing agent 51゛Physician Akazawa- Hiroshi

Claims (1)

[Claims] A cup-shaped housing, a ring-shaped circular spline rotatably supported on the inner periphery of the housing, and a cup arranged inside the circular spline and engaged with the circular spline by being biased by a wave generator. A harmonic reducer is formed by fixing a shaped flexspline to the housing, and a casing having one end of a spindle fixed to the housing and rotating around the spindle is disposed inside the flexspline, What is claimed is: 1. A power unit comprising a hydraulic motor and a hydraulic motor provided with a wave generator, and configured such that rotational output can be taken out from the circular spline.