Anti-backlash structure for scissors gear

Abstract

An anti-backlash structure for a scissors gear is provided including a scissors gear and a cam gear which are coaxially connected to rotate relative to each other, an end piece which has one side which is press-fitted into a cam shaft so that the end piece rotates together with the cam shaft, the other side which is in surface-to-surface contact with the scissors gear, and a circumferential surface with which the cam gear is press-fitted; a bolt which is coupled to an inner diameter portion of the scissors gear, penetrates the end piece, and is inserted into the cam shaft; and a scissors spring which has one side coupled to the end piece, and the other side coupled to the bolt. When the end piece rotates, the scissors spring rotates the scissors gear relative to the cam gear through the bolt and allows the scissors gear to come into close contact with the cam gear.

Claims

1. An anti-backlash structure for a scissors gear, the anti-backlash structure comprising: a scissors gear and a cam gear which are coaxially connected to rotate relative to each other; an end piece which has one side which is press-fitted into a cam shaft so that the end piece rotates together with the cam shaft, the other side which is in surface-to-surface contact with the scissors gear, and a circumferential surface with which the cam gear is press-fitted; a bolt which is coupled to an inner diameter portion of the scissors gear, penetrates the end piece, and is inserted into the cam shaft; and a scissors spring which has one side coupled to the end piece, and the other side coupled to the bolt, wherein when the end piece rotates, the scissors spring rotates the scissors gear relative to the cam gear through the bolt and allows the scissors gear to come into close contact with the cam gear; wherein the bolt further includes a bolt cap which is press-fitted with an inner diameter portion of the scissors gear, and a rod portion which is coupled to the bolt cap.

2. The anti-backlash structure of claim 1, wherein the end piece further includes a press-fit groove which is formed in a circumferential surface of the end piece so that the cam gear is in contact with the scissors gear and press-fitted with the end piece.

3. The anti-backlash structure of claim 1 wherein an internal thread and an external thread are formed on an outer diameter portion of the rod portion and an inner diameter portion of the bolt cap, respectively.

4. The anti-backlash structure of claim 1, wherein an inner diameter of the end piece is greater than an outer diameter of the bolt, such that the bolt rotates inside the end piece.

5. The anti-backlash structure of claim 1, wherein the end piece further includes an insertion groove which is formed at a lateral side of the scissors spring so as to accommodate the scissors spring.

6. The anti-backlash structure of claim 5, wherein the scissors spring further includes a straight portion which is inserted into the insertion groove such that the scissors spring and the end piece are coupled to each other.

7. The anti-backlash structure of claim 1, wherein the scissors spring further includes a through portion through which the bolt vertically penetrates such that the scissors spring and the bolt are coupled to each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an exploded perspective view of an anti-backlash structure for a scissors gear according to an embodiment of the present disclosure.

(2) FIG. 2 is a cross-sectional view of the anti-backlash structure for the scissors gear according to an embodiment of the present disclosure.

(3) FIG. 3 is a perspective view of the anti-backlash structure for the scissors gear according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(4) Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure is not restricted or limited by exemplary embodiments. Like reference numerals indicated in the respective drawings refer to members which perform substantially the same functions.

(5) An object and an effect of the present disclosure may be naturally understood or may become clearer from the following description, and the object and the effect of the present disclosure are not restricted only by the following description. In addition, in the description of the present disclosure, the specific descriptions of publicly known technologies related with the present disclosure will be omitted when it is determined that the specific descriptions may unnecessarily obscure the subject matter of the present disclosure.

(6) FIG. 1 is an exploded perspective view of an anti-backlash structure for a scissors gear 400 according to the present disclosure.

(7) Referring to FIG. 1, the anti-backlash structure for the scissors gear 400 according to the present disclosure may include a cam shaft 100, a scissors gear 400, a cam gear 300, an end piece 200, a bolt 500, and a scissors spring 600.

(8) The cam shaft 100 is rotatably provided to transmit power. The scissors gear 400 and the cam gear 300 may be coaxially connected to the cam shaft 100 and formed such that one surface of the scissors gear 400 and one surface of the cam gear 300 are to be in contact with each other.

(9) FIG. 2 is a cross-sectional view of the anti-backlash structure for the scissors gear 400 according to the present disclosure.

(10) Referring to FIG. 2, one side of the end piece 200 may be press-fitted into the cam shaft 100 such that the end piece 200 rotates together with the cam shaft 100, and the other side of the end piece 200 may be in surface-to-surface contact with the scissors gear 400.

(11) The cam gear 300 may be press-fitted with a circumferential surface of the end piece 200, such that the end piece 200, which is rotated along with the rotation of the cam shaft 100, rotates the cam gear 300.

(12) The end piece 200 may further include a press-fit groove 210 which is formed in the circumferential surface of the end piece 200 so as to have a width equal to a width of the cam gear 300 such that the cam gear 300 is in contact with the scissors gear 400 and press-fitted with the end piece 200.

(13) A press-fit protrusion 215 formed at a rear side of the press-fit groove 210 may prevent the cam gear 300 from being withdrawn when the end piece 200 and the scissors gear 400 are rotated.

(14) The bolt 500 may be coupled to an inner diameter portion of the scissors gear 400, penetrate the end piece 200, and be inserted into the cam shaft 100.

(15) The bolt 500 may further include a bolt cap 510 which is press-fitted into the inner diameter portion of the scissors gear 400, and a rod portion 520 which is coupled to the bolt cap 510, such that the bolt 500 is coupled to the scissors gear 400.

(16) An internal thread or an external thread is formed on an outer diameter portion of the rod portion 520, and a screw thread, which corresponds to the internal thread or the external thread, is formed on an inner diameter portion of the bolt cap 510, such that the rod portion 520 and the bolt 500 may be coupled to each other.

(17) One side of the scissors spring 600 is coupled to the end piece 200, and the other side of the scissors spring 600 is coupled to the bolt 500, thereby allowing the scissors gear 400 to rotate relative to the cam gear 300 through the bolt 500, when the end piece 200 is rotated, and allowing the scissors gear 400 to come into close contact with the cam gear 300.

(18) The end piece 200 has an insertion groove 230 formed at a lateral side of the scissors spring 600 so as to accommodate the scissors spring 600, and the scissors spring 600 has a straight portion 610 which is inserted into the insertion groove 230 such that the scissors spring 600 and the end piece 200 are coupled to each other. As a result, the end piece 200 and the scissors spring 600 may be coupled to each other.

(19) The scissors spring 600 has a through portion through which the bolt 500 vertically penetrates, such that the scissors spring 600 and the bolt 500 are coupled to each other. As a result, the scissors spring 600 may be coupled to the bolt 500.

(20) A mechanism of the anti-backlash structure for the scissors gear 400 will be described in detail with reference to FIG. 3.

(21) FIG. 3 is a perspective view of the anti-backlash structure for the scissors gear 400 according to the present disclosure.

(22) Referring to FIG. 3, the end piece 200 press-fitted into the cam shaft 100 is rotated along with the rotation of the cam shaft 100.

(23) The cam gear 300 inserted into the press-fit groove 210 is also rotated as the end piece 200 is rotated, and the scissors spring 600 coupled to the end piece 200 receives rotational force of the end piece 200.

(24) In this case, the bolt 500 connected to one end of the scissors spring 600 is rotated by elastic force of the scissors spring 600, and the scissors gear 400 having the inner diameter portion coupled to the bolt 500 is rotated relative to the cam gear 300.

(25) An inner diameter of the end piece 200 is greater than an outer diameter of the bolt 500, such that the bolt 500 may rotate inside the end piece 200 in a direction opposite to a direction in which the end piece 200 rotates.

(26) The elastic force of the scissors spring 600 rotates the bolt 500 and simultaneously pulls the scissors gear 400 coupled to the bolt 500 toward the cam gear 300, such that the scissors gear 400 and the cam gear 300 may come into close contact with each other.

(27) The elastic force of the scissors spring 600 may have an effect of damping an axial load of the cam shaft 100.

(28) According to the anti-backlash structure for the scissors gear 400 of the present disclosure, the scissors gear 400 and the cam gear 300 are in surface-to-surface contact with each other by the press-fit groove 210 and the press-fit protrusion 215 formed in/on the end piece 200. The scissors gear 400 is pulled toward the cam gear 300 by the elastic force of the scissors spring 600 such that the contact between the scissors gear 400 and the cam gear 300 is securely maintained, and as a result, it is possible to obtain stable dynamic characteristics and reduce rattling noise.

(29) The bolt 500, which rotates separately from the end piece 200, may be inserted into the cam shaft 100 to prevent the withdrawal of the scissors gear 400 and the cam gear 300. The bolt 500 may serve to transmit the elastic force of the scissors spring 600 to the scissors gear 400. As a result, it is possible to integrate a cup spring in the related art for preventing the withdrawal of the scissors gear 400 and the cam gear 300, a snap ring for fixing the scissors gear 400 and the cam gear 300, and a scissors spring in the related art for rotating the scissors gear 400 and a cam gear into the scissors spring 600.

(30) While a number of exemplary aspects have been discussed above, those of skill in the art will recognize that still further modifications, permutations, additions and sub-combinations thereof of the disclosed features are still possible. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.