Method of fabricating a reducer, and a robot incorporating such a reducer

Abstract

In order to fabricate an epicycloidal reducer including at least one circular cam (13, 15) whose outer peripheral edge (133, 153) is provided with a first set of teeth (134, 154) suitable for co-operating with a stationary second set of teeth, said cam being pierced by at least a first bore (135, 155) for receiving a drive finger held stationary in a second bore (176) formed in a support (17) secured to an outlet shaft of the reducer, the first bore (135, 155) in the or each cam (13, 15) and the second bore (176) in the support (17) are machined at least in part in a single operation while in alignment (X2) one with the other.

Description

The invention can be better understood and other advantages thereof appear more clearly in the light of the following description of a reducer in accordance with the invention and of its method of fabrication, given purely by way of example and made with reference to the accompanying drawings, in which:

FIG. 1 is an axial section of a reducer in accordance with the invention;

FIG. 2 is a fragmentary axial section of certain component elements of the reducer of FIG. 1 during a step in the fabrication of the reducer;

FIG. 3 is an axial section of a drive finger that can be used as a variant in the reducer of FIGS. 1 and 2; and

FIG. 4 is a theoretical diagrammatic view of a robot in accordance with the invention and incorporating, amongst other things, the reducer of FIGS. 1 and 2.

Claims

1. A method of fabricating an epicycloidal reducer (1) including at least one circular cam (13, 15) having an outer peripheral edge (133, 153) provided with a first set of teeth (134, 154) suitable for co-operating with a stationary second set of teeth (141) in which the number (N2) of teeth is different from the number (N1) of teeth in the first set, said cam being pierced by at least one first bore (135, 155) for receiving a drive finger (16) held stationary in a second bore (176) formed in a support (17) secured to an outlet shaft (12) of said reducer, the method being characterized in that it includes a step consisting in: a) machining (F2) at least partially in a single operation said first and second bores (135, 155; 176) in alignment (X2) with each other.

2. A method according to claim 1, characterized in that it includes steps consisting in: b) pressing said cam (13, 15) against said support (17) prior to step a); andc) subjecting said cam and said support as pressed one against the other in this way to a clamping force (F1) at least during step a).

3. A method according to claim 2, characterized in that during step c) said cam (15) and said support (17) have surfaces (157/177) pressing against each other in the zone in which said bores (135, 155, 176) are machined (F2) and, optionally, two adjacent cams (13, 15) have surfaces (135/156) pressing against each other in said zone.

4. A method according to claim 1, characterized in that during step a), said bores (135, 155, 176) are machined to the same diameter (D).

5. A method according to claim 1, for fabricating a reducer including a plurality of cams (13, 15) each provided with at least one first bore (135, 155), the method being characterized in that during step a), the first bores (135, 155) of all of the cams (13, 15) are machined together with the corresponding second bore (176) of said support (17).

6. An epicycloidal reducer (1) including at least one circular cam (13, 15) having an outer peripheral edge (133, 153) provided with a first set of teeth (134, 154) suitable for co-operating with a stationary second set of teeth (141) in which the number (N2) of teeth is different from the number (N1) of teeth in the first set, said cam being pierced by at least one first bore (135, 155) for receiving a drive finger (16) held stationary in a second bore (176) formed in a support (17) secured to an outlet shaft (12) of said reducer, the reducer being characterized in that said first and second bores (135, 155, 176) are identical in diameter (D).

7. A reducer according to claim 6, characterized in that said finger (16) is stepped and comprises two portions (161, 162) of different diameters (D1, D2), a first portion (161) having a diameter (D1) substantially equal to the diameter (D) of said bores (135, 155, 176) and being received in a bore (176) of said support (17), while a second portion (162) of diameter (D2) smaller than the diameter of the first portion is received in a bore (135, 155) of said or of each cam (13, 15).

8. A reducer according to claim 7, characterized in that it includes at least two cams (13, 15) that are eccentric in opposition about the axis (X1) of the inlet shaft (11) of the reducer, and in that the diameter (D) of said bores (135, 155, 176) is substantially equal to the sum of the diameter (D2) of the second portion (162) of said finger (16) plus twice the eccentricity (e) of said cams.

9. A reducer according to claim 6, characterized in that said or each cam (13, 15) is pierced by a plurality of bores (135, 155) distributed around its axis of rotation (X13, X15) about the inlet shaft (11) of said reducer, in that each bore receives a drive finger (16) held stationary on said support (17), and in that a ring (20) is constrained to rotate with the ends (168) of said fingers (16) that are opposite from said support (17).

10. A reducer according to claim 6, characterized in that said or each drive finger (16) is held stationary on said support (17) by means of a screw (18) extending along the longitudinal axis of said finger and screwed into said support (17) or into a part (12) that is secured to said support.

11. A robot (R) including a moving portion (202) driven by a motor (100) via a reducer, the robot being characterized in that said reducer (1) is according to claim 6.