JP2006300273A - Hypocycloid reduction gear with built-in motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hypocycloid reduction gear with a built-in motor enabling the stabilization of the support of an output shaft and a reduction in the size of a system to which the reduction gear is applied. <P>SOLUTION: Ball bearings 13 and 14 are installed on opposed wall parts to a case member 10 (first and second cases 11, 12), and the output shaft 15 is installed across the opposed wall parts of the case member 10 and supported by the bearings 13 and 14. The output shaft 15 is formed hollow, and a female screw part 15d is formed in the inner peripheral surface of the output shaft, and a translation screw 30 is inserted into the output shaft 15 (insertion hole 15c) so as to be threaded with the female screw part 15d. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a motor-equipped hypocycloid speed reducer in which an electric motor and a speed reduction mechanism are integrated on the same axis.

  Conventionally, there have been various types of configurations in which a reduction mechanism is attached to an electric motor for the purpose of obtaining a high torque at a low speed. In many of these cases, the assembly of the speed reduction mechanism and the assembly of the electric motor are separately manufactured, and are then assembled together by being connected together. There is a hypocycloid mechanism as one of the reduction mechanisms, and a reduction gear using this hypocycloid mechanism has been proposed (see Patent Document 1).

In this hypocycloid reduction mechanism, first, a rotor of an electric motor (electric drive unit) is rotatably provided on the outer periphery of the output shaft, and a stator is disposed on the outer periphery of the rotor. The rotor rotates an eccentric shaft portion (eccentric body) offset with respect to the rotation axis of the rotor, and a planetary gear (planetary external gear) provided via the eccentric shaft portion and a bearing is fixed to the case. Revolves along the ring gear (fixed sun internal gear). At the same time, since the revolving planetary gear rotates by meshing with the ring gear, the rotation of the planetary gear is transmitted to the output shaft via the output panel, so that a deceleration output can be obtained from the output shaft.
JP 2000-120810 A

  By the way, in a speed reducer using such a hypocycloid speed reduction mechanism, the planetary gear is decentered and rotated. Therefore, a meshing failure that causes abnormal noise is likely to occur in the speed reduction mechanism, and the meshing is severe. There is a need. Therefore, it is required to stably support the output shaft that is drivingly connected to the planetary gear and to reduce the deflection of the output shaft.

  In addition, when the speed reducer is used in a system that converts the rotational motion of the output shaft into a reciprocating linear motion using a screw action, the system will be enlarged unless the speed reducer and the system are suitably connected. . Therefore, it is required that the reduction gear and the system are suitably connected.

  An object of the present invention is to provide a hypocycloid reducer with a built-in motor that can stabilize the support of the output shaft and contribute to downsizing of the applied system.

  According to the first aspect of the present invention, a case member, a motor unit that is disposed in the case member and rotationally drives the rotor, and cannot move on the same axis as the central axis of the rotor in the case member. A hypocycloidal speed reduction comprising: a ring gear provided; and a planetary gear that is arranged eccentrically with respect to the central axis inside the ring gear, revolves based on rotation of the rotor, and rotates by meshing with the ring gear. A mechanism and an output shaft that is supported by the case member so as to be rotatable coaxially with the central axis, rotates with the rotation of the planetary gear by connection with the planetary gear, and drives a load by the rotation; A hypocycloid speed reducer with a built-in motor, wherein bearing members are provided on opposing wall portions of the case member, and the output shaft is connected to the casing by each bearing member. The output shaft is hollow and formed with a female screw portion on its inner peripheral surface, and a linear screw is screwed with the female screw portion to support the inner wall of the output shaft. The gist of this is that it is inserted and configured.

  The gist of the invention according to claim 2 is that, in the hypocycloid speed reducer with built-in motor according to claim 1, the female screw portion is provided in a part of the axial direction of the output shaft.

  According to a third aspect of the present invention, in the hypocycloid speed reducer with a built-in motor according to the second aspect, the female screw portion is set on the opposite side in the axial direction from the connecting portion of the output shaft to the speed reduction mechanism. This is the gist.

  According to a fourth aspect of the present invention, in the hypocycloid speed reducer with a built-in motor according to the second or third aspect, the female thread portion is provided on an inner peripheral surface of a portion supported by the bearing member of the output shaft. This is the gist.

(Function)
According to the first aspect of the present invention, the bearing members are respectively provided on the opposing wall portions of the case member of the speed reducer, and the output shaft is bridged and supported between the opposing wall portions of the case member by each bearing member. . Therefore, since the output shaft is supported by the two bearing members separated as much as possible in the case member, the output shaft is stably supported, and the deflection of the output shaft is small. Therefore, since the influence on the speed reduction mechanism due to the swing of the output shaft is suppressed, a hypocycloid speed reduction mechanism that needs to be severely meshed with the speed reduction mechanism is used. It is possible to suppress the occurrence of abnormal noise. Further, the output shaft is hollow, a female screw portion is formed on the inner peripheral surface thereof, and the linear motion screw is inserted into the output shaft so as to be screwed with the female screw portion. In other words, since the output shaft is supported between the opposing wall portions of the case member in order to stabilize the output shaft, the output shaft is configured to be long, and thereby a space for inserting the linear motion screw. Can be secured in the output shaft. Therefore, the amount of protrusion of the linear motion screw in the axial direction can be suppressed, and it is possible to contribute to the downsizing of the system operated using the linear motion screw.

  According to the invention described in claim 2, the female screw portion is provided in a part of the output shaft in the axial direction. In other words, since the output shaft is configured to be long so as to be bridged between the opposing wall portions of the case member, by providing the female screw portion in part rather than in the entire axial direction of the output shaft, The sliding resistance at the time of driving transmission to the direct acting screw can be reduced. Thereby, the drive loss between a female screw part and a direct-acting screw can be made as small as possible.

  According to the third aspect of the present invention, the female thread portion is set on the opposite side in the axial direction from the connecting portion of the output shaft with the speed reduction mechanism. That is, since a load acts on the female screw portion, the portion near the female screw portion is likely to be bent. Therefore, by separating the female screw part from the connecting part with the speed reduction mechanism as an opposite side in the axial direction, the influence of the bending on the speed reduction mechanism can be suppressed, and the speed reduction mechanism can be engaged. It can be maintained well.

  According to the fourth aspect of the present invention, the female screw portion is provided on the inner peripheral surface of the portion supported by the bearing member of the output shaft. As described above, since a load acts on the female screw part, the vicinity of the female screw part is likely to be bent. Therefore, by providing such a female screw portion on the inner peripheral surface of the portion supported by the bearing member, the occurrence of the bending can be suppressed as much as possible. Also by this, the meshing of the speed reduction mechanism can be maintained well.

  According to the present invention, it is possible to provide a hypocycloid reducer with a built-in motor that can stabilize the support of the output shaft and contribute to downsizing of the applied system.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 shows a hypocycloid reducer with a built-in motor in the present embodiment. In FIG. 1, a case member 10 is composed of a first case 11 and a second case 12, both of which are substantially bowl-shaped, and forms a space for housing a component therein. A ball bearing 13 is provided in the central portion of the first case 11, and a ball bearing 14 is provided in the central portion of the second case 12, and both end portions of the output shaft 15 of the speed reducer are formed by both bearings 13, 14. Is rotatably supported. That is, the output shaft 15 is supported by being spanned between the opposing wall portions of the cases 11 and 12.

  In the first case 11, a motor unit M including a permanent magnet 16 that forms a stator, a rotor core 17 and a winding 18 that form a rotor, and a rectifying mechanism 19 that includes a brush and a commutator is formed. ing. A plurality of permanent magnets 16 are fixed to the inner peripheral surface of the first case 11. An annular rotor core 17 around which a winding 18 is wound is rotatably supported on the output shaft 15 via a ball bearing 20 inside the permanent magnet 16. A rectifying mechanism 19 is disposed in a space provided on one side in the axial direction of the rotor core 17 (on the ball bearing 13 side), and the rectifying mechanism 19 supplies an external power to the winding 18.

  On the other side in the axial direction of the rotor core 17 (the side opposite to the rectifying mechanism 19), an eccentric portion 17a that is recessed in the axial direction is provided on the inner side of the portion around which the winding 18 is wound. The eccentric portion 17a has an eccentric axis L2 that is eccentric with respect to the central axis L1 of the output shaft 15 as its central axis. A ball bearing 21 is fitted into the eccentric portion 17a, and the planetary gear 25 is rotatably supported by the ball bearing 21. That is, the planetary gear 25 is arranged eccentrically with respect to the output shaft 15 by the eccentric portion 17a.

  The planetary gear 25 is provided with a mounting portion 25c that protrudes in a cylindrical shape from the center to one axial direction. The mounting portion 25c is fitted inside the ball bearing 21 and allows the output shaft 15 to pass therethrough. The planetary gear 25 includes a first gear portion (external gear) 25a and a second gear portion (external gear) 25b having a smaller diameter than the first gear portion 25a on the other side in the axial direction. These first and second gear portions 25a and 25b are provided on a coaxial line and coincide with the eccentric axis L2.

  The first gear portion 25 a is meshed with a ring gear (internal gear) 26 that is fixed to the inner peripheral surface of the second case 12. The ring gear 26 is provided such that its center axis coincides with the center axis L 1 of the output shaft 15. The ring gear 26 has a larger diameter than the first gear portion 25a (in this case, the radius of the ring gear 26 is a value obtained by adding the eccentric distance of the gear portion 25a to the radius of the first gear portion 25a).

  The second gear portion 25 b is meshed with a ring gear portion (internal gear) 15 b of an output board 15 a provided on the output shaft 15. The ring gear portion 15 b is provided so that its center axis coincides with the center axis L 1 of the output shaft 15. The ring gear portion 15b has a larger diameter than the second gear portion 25b (in this case, the radius of the ring gear portion 15b is a value obtained by adding the eccentric distance of the gear portion 25b to the radius of the second gear portion 25b). . In addition to the ring gear portion 15b, the planetary gear 25 and the ring gear 26 constitute a hypocycloid reduction mechanism G.

  The output shaft 15 is set to a length between the outsides of the bearings 13 and 14 that support both ends, and is set to a length that does not protrude outward from the bearings 13 and 14. On the other side of the output shaft 15 in the axial direction, the output board 15a is provided. The output shaft 15 is formed in a hollow shape, and has an insertion hole 15c for inserting the linear motion screw 30 therein. On the inner peripheral surface of the insertion hole 15c, a female screw portion 15d that is screwed with the linear motion screw 30 is formed. The female screw portion 15d is formed in a predetermined range X on one side in the axial direction, that is, on the opposite side in the axial direction from the output board 15a and supported by the ball bearing 13. The linear motion screw 30 is inserted into the insertion hole 15 c and the female screw portion 15 d is screwed with the linear motion screw 30.

  In the above configuration, when the motor unit M is energized, a current corresponding to the rotational position flows through the winding 18 via the rectifying mechanism 19, the rotor core 17 is magnetized, and the permanent magnet 16 is attracted or repelled. In response, the rotor core 17 (rotor) rotates about the output shaft 15.

  At this time, the planetary gear 25 supported by the eccentric portion 17a via the ball bearing 21 revolves around the center axis L1 of the output shaft 15. Further, since the first gear portion 25a of the planetary gear 25 meshes with the ring gear 26, the planetary gear 25 rotates while revolving, and the trajectory of the planetary gear 25 becomes a hypocycloid. Similarly, the second gear portion 25b of the planetary gear 25 draws a hypocycloid locus. Since the second gear portion 25b meshes with the ring gear portion 15b of the output shaft 15 (output board 15a), the output shaft 15 rotates as the second gear portion 25b rotates. The rotation of the output shaft 15 at this time is a rotation decelerated with respect to the rotation of the rotor core 17 (rotor) because the diameter of the second gear portion 25b is smaller than the diameter of the first gear portion 25a. . The rotation of the output shaft 15 is transmitted from the female screw portion 15d to the linear motion screw 30.

  Incidentally, the direct acting screw 30 is non-rotatably attached to a system (not shown) operated by the speed reducer. When the output shaft 15 rotates as described above, the linear motion screw 30 screwed by the female screw portion 15d is converted into a reciprocating linear motion by the screw action, and the system performs a predetermined operation by this reciprocating linear motion. It has become.

Next, effects obtained in the present embodiment will be described below.
(1) Ball bearings 13 and 14 are provided on opposing wall portions of the case member 10 (first and second cases 11 and 12), and the output shaft 15 is the opposing wall of the case member 10 at each bearing 13 and 14. It is supported across the clubs. Therefore, since the output shaft 15 is supported by the two bearings 13 and 14 separated as much as possible in the case member 10, the output shaft 15 can be stably supported and the deflection of the output shaft 15 is reduced. be able to. Therefore, since the influence on the speed reduction mechanism G due to the swing of the output shaft 15 can be suppressed, a hypocycloid speed reduction mechanism that needs to be engaged with the speed reduction mechanism G as in the present embodiment is used. The meshing of the speed reduction mechanism G can be maintained satisfactorily, and the occurrence of abnormal noise can be suppressed. Further, the output shaft 15 is hollow, and an internal thread portion 15d is formed on the inner peripheral surface thereof. The linear motion screw 30 is inserted into the output shaft 15 (insertion hole 15c) so as to be screwed with the internal thread portion 15d. Is done. That is, since the output shaft 15 is bridged and supported between the opposing wall portions of the case member 10 in order to stabilize the output shaft 15, the output shaft 15 is configured to be long, and thereby the linear motion screw. A sufficient space for inserting 30 can be secured in the output shaft 15. Therefore, the amount of protrusion of the linear motion screw 30 in the axial direction can be suppressed, and it is possible to contribute to the downsizing of the system operated using the linear motion screw 30.

  (2) The female screw portion 15d is provided in a part of the output shaft 15 in the axial direction (predetermined range X). That is, since the output shaft 15 is configured to be long so as to be bridged between the opposing wall portions of the case member 10, the female screw portion 15 d is not provided in the entire axial direction of the output shaft 15 but partly. By providing, the sliding contact resistance at the time of drive transmission to the linear motion screw 30 can be reduced. Thereby, the drive loss between the internal thread part 15d and the direct-acting screw 30 can be minimized.

  (3) The female screw portion 15d is set on the opposite side in the axial direction from the connecting portion (the output panel 15a) of the output shaft 15 with the speed reduction mechanism G. That is, since a load acts on the female screw portion 15d, the portion near the female screw portion 15d is likely to be bent. Therefore, by separating the female screw portion 15d from the connecting portion with the speed reduction mechanism G so as to be opposite to each other in the axial direction, the influence on the speed reduction mechanism G due to the bending can be suppressed to be small. Good meshing of G can be maintained.

  (4) The female screw portion 15 d is provided on the inner peripheral surface of the portion of the output shaft 15 that is supported by the ball bearing 13. As described above, since a load acts on the female screw portion 15d, the vicinity of the female screw portion 15d is likely to be bent. Therefore, by providing such a female screw portion 15d on the inner peripheral surface of the portion supported by the bearing 13, the occurrence of the bending can be suppressed as much as possible. Also by this, the meshing of the speed reduction mechanism G can be maintained satisfactorily.

  (5) Since the output shaft 15 is supported across the opposing wall portions of the case member 10, the rotor core 17 (rotor) is provided so that the output shaft 15 penetrates. The rotor core 17 is rotatably supported with respect to the output shaft 15 via a ball bearing 20. Therefore, it is not necessary to specially configure a means for rotatably supporting the rotor core 17, and it is possible to obtain an effect that, for example, it can contribute to space saving of the reduction gear.

  (6) The two bearings 13 and 14 that support the output shaft 15 and the bearing 20 that supports the rotor core 17 are constituted by ball bearings. That is, since these ball bearings 13, 14, and 20 can not only support in the radial direction but also regulate the movement in the axial direction, a means for regulating the movement of the output shaft 15 and the rotor core 17 in the axial direction is specially configured. There is no need, and for example, the effect of reducing the number of parts can be obtained.

  (7) The rotor core 17 is provided with an eccentric portion 17a eccentric to the central axis L1, and a planetary gear 25 is attached to the eccentric portion 17a via a ball bearing 21. That is, the planetary gear 25 can be easily arranged eccentrically only by attaching the planetary gear 25 to the eccentric portion 17a. Moreover, since the eccentric part 17a is provided integrally with the rotor core 17, the number of parts does not increase. Further, since the eccentric portion 17a is a concave portion that can accommodate a part of the bearing 21 and the planetary gear 25, the axial size can be reduced.

  (8) Since the bearing 21 for supporting the planetary gear 25 is constituted by a ball bearing capable of restricting movement in the axial direction in addition to supporting in the radial direction, a means for restricting movement of the planetary gear 25 in the axial direction is specially provided. There is no need to configure, and for example, an effect that the number of parts can be reduced can be obtained.

The embodiment of the present invention may be modified as follows.
In the above embodiment, the axial length of the output shaft 15 is set to the length between the outsides of the bearings 13 and 14, but it may be set longer than this. That is, the output shaft 15 may protrude from the bearings 13 and 14. Further, although the female screw portion 15d inside the output shaft 15 is provided on the opposite side of the output plate 15a of the output shaft 15 in the axial direction, the female screw portion 15d may be provided on the output plate 15a side. Further, the female screw portion 15 d may be provided at a position shifted from the ball bearing 13 of the output shaft 15. In this case, the female screw portion 15d may be provided in the other bearings 14, 20, and 21 and may be provided in portions other than the bearings 14, 20, and 21. Further, the female screw portion 15 d may be provided in the entire axial direction of the output shaft 15.

In the above embodiment, the bearings 13, 14, 20, and 21 are all ball bearings. However, the bearings are not limited to ball bearings, and for example, sliding bearings may be used.
In the above embodiment, the rotor core 17 is supported by the bearing 20 with respect to the output shaft 15. However, for example, a support portion that supports the rotor core 17 is provided on the case member 10, and the rotor core 17 is supported by the support portion. It may be.

  In the above embodiment, the rotor core 17 is provided with the concave eccentric portion 17a and the planetary gear 25 is assembled. However, the eccentric portion may be convex. Alternatively, the eccentric portion may be configured by a separate member and assembled to the rotor core 17.

  In the above embodiment, the motor unit M having the configuration using the rectifying mechanism 19 that mechanically rectifies with a brush and a commutator is incorporated, but a so-called brushless motor that electrically performs the rectifying mechanism 19 may be incorporated.

Next, technical ideas that can be grasped from the above-described embodiment and other examples will be described below.
(A) In the motor built-in hypocycloid reducer according to any one of claims 1 to 4,
The rotor is provided so that the output shaft passes therethrough, and is supported so as to be rotatable with respect to the output shaft via a bearing member.

  In this way, since the output shaft is supported across the opposing wall portions of the case member, the rotor is provided so that the output shaft penetrates. The rotor is supported rotatably with respect to the output shaft via a bearing member. Therefore, there is no need to specially configure a means for rotatably supporting the rotor, and for example, an effect that it can contribute to space saving of the reduction gear is obtained.

(B) In the motor-equipped hypocycloid reducer described in (b) above,
A hypocycloid reducer with a built-in motor, wherein at least one of the bearing members that support the output shaft and the bearing member that supports the rotor are configured by ball bearings.

  With this configuration, at least one of the bearing members that support the output shaft and the bearing member that supports the rotor are configured as ball bearings. That is, since the ball bearing can not only support the radial direction but also regulate the movement in the axial direction, there is no need to specially configure means for regulating the movement of the output shaft and the rotor in the axial direction. Can be obtained.

(C) In the hypocycloid reducer with a built-in motor according to any one of claims 1 to 4 and (a) and (b) above,
A hypocycloid reducer with a built-in motor, wherein the rotor is provided with an eccentric portion eccentric to the central axis, and the planetary gear is attached to the eccentric portion via a bearing member.

  In this way, the rotor is provided with an eccentric portion that is eccentric with respect to the central axis, and the planetary gear is attached to the eccentric portion via the bearing member. That is, the planetary gear can be easily arranged eccentrically only by attaching the planetary gear to the eccentric portion. Further, since the eccentric portion is provided integrally with the rotor, the number of parts is not increased. Incidentally, if this eccentric part is a recess capable of accommodating a part of the bearing member or the planetary gear, it is possible to reduce the axial size.

(D) In the motor-equipped hypocycloid reducer described in (c) above,
A hypocycloid speed reducer with a built-in motor, wherein the bearing member for supporting the planetary gear is constituted by a ball bearing.

  In this way, since the bearing member that supports the planetary gear is configured by a ball bearing that can restrict movement in the axial direction in addition to radial support, a special means for restricting the movement of the planetary gear in the axial direction is provided. There is no need to configure the device, and for example, the effect of reducing the number of components can be obtained.

It is sectional drawing which shows the hypocycloid reduction gear of this Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Case member, 13 ... Ball bearing as a bearing member, 14 ... Ball bearing as a bearing member, 15 ... Output shaft, 15a ... Output board equivalent to the connection part of a reduction mechanism, 15 ... Female screw part, 17 ... Rotation Rotor core constituting child, 25 ... planetary gear, 26 ... ring gear, 30 ... linear motion screw, G ... hypocycloid reduction mechanism, M ... motor part, L1 ... central axis.

Claims (4)

A case member;
A motor unit that is disposed in the case member and rotationally drives the rotor;
A ring gear provided coaxially with the central axis of the rotor in the case member so as to be immovable, and arranged eccentrically with respect to the central axis inside the ring gear, and revolved based on the rotation of the rotor. And a hypocycloid reduction mechanism having a planetary gear that rotates by meshing with the ring gear;
An output shaft that is supported by the case member so as to be rotatable coaxially with the central axis, rotates with the rotation of the planetary gear by connection with the planetary gear, and drives a load by the rotation;
A hypocycloid speed reducer with a built-in motor,
A bearing member is provided on each opposing wall portion of the case member, and the output shaft is supported across the opposing wall portions of the case member by each bearing member,
The motor built-in hypo, wherein the output shaft is hollow and has a female screw portion formed on an inner peripheral surface thereof, and a linear motion screw is screwed into the female screw portion and inserted into the output shaft. Cycloid reducer. In the hypocycloid reducer with a built-in motor according to claim 1,
A hypocycloid reducer with a built-in motor, wherein the female thread portion is provided in a part of the output shaft in the axial direction. In the hypocycloid reducer with a built-in motor according to claim 2,
A hypocycloid speed reducer with a built-in motor, wherein the female screw portion is set on the opposite side in the axial direction from the connecting portion of the output shaft to the speed reduction mechanism. In the motor built-in hypocycloid reducer according to claim 2 or 3,
A hypocycloid reducer with a built-in motor, wherein the female thread portion is provided on an inner peripheral surface of a portion of the output shaft supported by the bearing member.

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