JP2005240843A - Scissors gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make backlash reduction performance of the scissors gear demonstrated at maximum by suppressing inclination of a sub gear under a meshing and rotating condition of the scissors gear and a mating gear. <P>SOLUTION: In the scissors gear provided with: the main gear 20, the sub gear 22 having same tooth shape and tooth number as the main gear and provided adjacently and coaxially with the main gear in such a manner that the sub gear can relatively rotate; and a elastic member 24 energizing the sub gear in a circumference direction in relation to the main gear, an abutment part 36 for slidably abutting to the sub gear and the elastic member mutually is provided, while the abutment part 36 is constituted of an inclined surface 32 or curved surface. When the elastic member is deformed, the sub gear is energized also in an axial direction toward the main gear side, inclination torque acting on the sub gear is canceled by the axial direction force f2 to suppress inclination of the sub gear. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a scissor gear, and more particularly to a scissor gear configured to elastically pinch a mating gear tooth between a main gear tooth and a sub gear tooth to eliminate backlash with the mating gear.

  For example, in an engine or transmission of an automobile, a gear rattling sound (rattle sound) based on the rotational fluctuation is generated in a gear mechanism portion where the rotational fluctuation occurs. In order to suppress gear noise based on the rattling noise, scissor gears that eliminate backlash with the counterpart gear are suitably used (see, for example, Patent Documents 1 and 2). In a gear transmission device connected to a fuel injection pump or a camshaft or the like in the field of an automobile engine, a torque fluctuation or a rotation fluctuation caused by pumping or intake / exhaust of the pump occurs, so a scissor gear is used as a driving or driven gear. There are many cases.

  An example of the scissor gear according to the conventional example is shown in FIGS. The scissor gear has a main gear 2 that has a predetermined number of teeth and is fixed to the rotary shaft 1, has the same tooth shape and the same number of teeth as the main gear 2, and is adjacent to the main gear 2 on the same axis so as to be rotatable relative to the main gear 2. 2 and the sub gear 3 meshing with the counterpart gear 8, and one spring 7 for biasing the main gear 2 and the sub gear 3 in the circumferential direction. The spring 7 is typically a C-shaped torsion spring as shown in the figure, and is installed in a groove 6 recessed in the main gear 2. The main gear 2 is provided with a first pin 5 for locking one end of the spring 7, and the sub gear 3 is provided with a second pin 4 for locking the other end of the spring 7. Then, the main gear 2 and the sub-gear 3 are engaged with the counterpart gear 8 as shown in FIG. 24 in a state where the spring 7 is twisted in the circumferential direction, and the teeth of the counterpart gear 8 are engaged with the main gear 2 and the sub-gear. The backlash with the counterpart gear 8 is eliminated by elastically pinching with the third tooth.

  The sub gear 3 is rotatably supported on the outer periphery of the cylindrical bearing portion 2a of the main gear 2. Recessed seats 9 and 10 for receiving and engaging the first and second pins 5 and 4 are formed at both ends of the spring 7. The scissor gear is assembled by using a disc spring 11 and a snap ring 12. That is, after the spring 7 is accommodated in the groove 6, the sub gear 3 is slidably fitted on the outer periphery of the bearing portion 2 a while engaging the concave seats 9, 10 at both ends with the first and second pins 5, 4. Further, a disc spring 11 is fitted on the outer periphery of the bearing portion 2a, and the snap ring 12 is fitted into the ring groove 13 of the bearing portion 2a while the sub-gear 3 is lightly pressed against the main gear 2 by the disc spring 11. This completes the assembly of the scissor gear as a unit.

JP-A-9-170648 JP 2001-12581 A JP 2001-12582 A Japanese Utility Model Publication No. 53-30080 Japanese Utility Model Publication No. 63-180766 Japanese Utility Model Publication No. 62-54367

  By the way, when the scissor gear and the counterpart gear are rotating in mesh with each other, a tilting torque T2 for tilting the sub gear with respect to the axial direction is generated (see FIG. 22). As described in Patent Document 2, paragraphs 0037 to 0045, the axial position of the spring force by the spring acting on the sub gear, the reaction force received by the sub gear from the counterpart gear, and the reaction force received by the sub gear from the bearing portion. It is thought that each is different.

  Due to this tilting torque T2, the sub gear tilts with respect to the axial direction. As a result, the friction between the main gear and the sub gear increases more than necessary, the friction between the sub gear and its bearing also increases, and the spring force by the spring is increased by the sub gear. Therefore, there is a problem that the followability of the sub gear with respect to the main gear is deteriorated, the backlash reduction effect by the sub gear is reduced, and further, a wear phenomenon such as fretting occurs.

  In particular, in a gear transmission in which torque fluctuation / rotation fluctuation appears, it is effective to increase the spring force of the spring as the torque fluctuation increases in order to suppress gear noise due to backlash as much as possible. However, as the spring force is increased, the tilting torque T2 is also increased, and the above problem becomes remarkable. The present invention has been devised to solve such problems inherent in scissor gear application.

  An object of the present invention is to prevent the inclination of the sub gear in the scissor gear.

  Another object of the present invention is to suppress friction caused by the inclination of the sub gear, to maximize the backlash reduction performance inherent to the scissor gear, and to suppress wear based on the friction.

  A further object of the present invention is to provide a scissor gear capable of applying a force toward the main gear to the sub gear according to the magnitude of the force when a force is applied to the sub gear from the counterpart gear.

  According to the present invention, the main gear has the same tooth shape and the same number of teeth as the main gear, and is adjacent to the main gear so as to be rotatable relative to the main gear, and the main gear to urge the sub gear in the circumferential direction relative to the main gear. Provided with a fixed elastic member, each provided with a contact portion for slidably contacting the sub-gear and the elastic member, wherein at least one of the contact portions is formed of an inclined surface or a curved surface Thus, a scissor gear is provided in which the sub gear is simultaneously urged in the circumferential direction and the axial direction toward the main gear when the elastic member is deformed.

  Preferably, the elastic member is a leaf spring. In this case, preferably, an opening is provided through the side surface of the sub gear, the leaf spring is positioned in the opening and fixed to the main gear, and one end edge of the opening is on the sub gear side. An inclined surface forming an abutting portion is formed, and a tip portion of the leaf spring is curved so as to follow the inclined surface to form an abutting portion of the elastic member.

  Preferably, a convex portion that forms a contact portion on the sub gear side is provided on a side surface portion of the sub gear, and an opening portion is provided in proximity to the convex portion and penetrating the side surface of the sub gear. A support member for fixing the leaf spring away from the main gear is provided therein, and a distal end portion of the leaf spring is curved so as to be slidable with respect to the convex portion, so that the elastic member contacts Part. More preferably, the contact portion of the convex portion with the leaf spring is an inclined surface that follows the curvature of the leaf spring.

  According to the present invention, when the sub gear is rotated relative to the main gear, the elastic member is deformed and the sub gear is biased in the axial direction toward the main gear simultaneously with the circumferential direction. This axial force cancels the tilting torque and suppresses the tilt of the sub gear. Therefore, the friction caused by this inclination is suppressed, the backlash reduction performance inherent to the scissor gear can be maximized, and wear due to the friction can also be suppressed.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>
A scissor gear according to a first embodiment of the present invention is shown in FIGS. 1 shows the scissor gear after assembly, and FIG. 2 shows a part of the details. 3 to 5 are component diagrams of a sub-gear, a main gear, and a leaf spring as an elastic member, respectively.

  As shown in FIG. 1, the scissor gear includes a main gear 20 having a predetermined number of teeth on the outer periphery, a sub gear 22 having the same shape and number of teeth as the main gear 20 on the outer periphery, and adjacent to the main gear 20 in the axial direction. A leaf spring 24 that urges the sub gear 22 in the circumferential direction with respect to the main gear 20 is provided. In FIG. 1A, the sub gear 22 is on the front side in the thickness direction of the drawing, and the main gear 20 is on the far side. Therefore, hereinafter, the front side in the axial direction of the paper surface in the thickness direction is referred to as “anti-main gear side”, and the back side in the paper surface thickness direction is referred to as “main gear side”. The rotation direction of the main gear 2 in use is clockwise as indicated by an arrow. Hereinafter, this rotation direction is simply referred to as “rotation direction”, and the opposite rotation direction is referred to as “counter rotation direction”.

  In this embodiment, the main gear 20 is rotatably attached to the outer periphery of the rotating shaft, and has a metal bearing portion 26 on the inner periphery thereof. The sub gear 22 is rotatably supported on the outer periphery of the cylindrical bearing portion 28 of the main gear 20. As a result, the main gear 20 and the sub gear 22 can rotate relative to each other, but the sub gear 22 may be attached to the outer periphery of the rotating shaft so as to be directly rotatable. The sub gear 22 is mainly used for the purpose of preventing backlash and is not actively used for transmission of driving force, so that the tooth thickness thereof is made thinner than that of the main gear 20. As the main gear 20 and the sub gear 22, for example, a helical gear or a spur gear is used.

  A plurality of leaf springs 24 are preferably provided in the circumferential direction. In the present embodiment, four leaf springs 24 are provided at equal intervals in the circumferential direction. Its shape is rectangular. It is preferable that the elastic member has a length equal to or less than a length at which the circumference is divided into a plurality at a radial position where the elastic member is attached. The base end of the leaf spring 24 is fixed to the main gear 20 by a fastening member such as a bolt 30. The tip of the leaf spring 24 is slidably contacted with an inclined surface 32 provided on the sub gear 22. A plurality of these abutting portions 36 are preferably provided in the circumferential direction as in the number of the leaf springs 24, and in this embodiment, provided at four locations at intervals of 90 ° in the circumferential direction. The width direction of the contact portion 36 (that is, the width direction of the leaf spring 24 and the inclined surface 32) is matched with the radial direction, and the longitudinal direction perpendicular to the width direction is matched with the tangential direction.

  As shown in FIG. 3, the sub-gear 22 is provided with an opening 34 having a size that is slightly larger than the leaf spring 24 so as to accommodate the leaf spring 24 so as to penetrate the side surface of the sub-gear 22. The shape of the opening 34 is rectangular according to the shape of the leaf spring 24. One end edge in the counter-rotating direction of the opening 34 is cut obliquely in an edge shape over the entire width, and the inclined surface 32 is formed. The inclined surface 32 formed in this way faces the non-main gear side and is not visible from the main gear side. The area of the opening 34 is smaller on the main gear side than on the non-main gear side.

  As shown in FIG. 1A, in a state where the leaf spring 24 is fixed in the opening portion 34, the contact portion 36 is positioned on the side opposite to the rotation direction with respect to the fixing portion by the bolt 30.

  As shown in FIG. 5, the leaf spring 24 has a bolt insertion hole 38 for inserting the bolt 30 at the base end portion, and further has a claw portion 40 bent at the end edge on the main gear side. Corresponding to these, the main gear 20 is also provided with a screw hole 42 and an engaging groove 44 (see FIG. 4). The distal end portion of the leaf spring 24 is curved to the side opposite to the main gear so as to follow the inclined surface 32 (curved portion 46).

  Regarding the assembly of the scissor gear, the sub gear 22 is fitted to the bearing portion 28 of the main gear 20 and overlapped with the main gear, and the phase of the sub gear 22 is adjusted so that the relative positions of the opening 34 and the screw hole 42 and the engaging groove 44 are matched. Then, the leaf spring 24 is inserted into the opening 34 from the side opposite to the main gear, the claw portion 40 of the leaf spring 24 is positioned in the engagement groove 44, and the bolt 30 is tightened in the screw hole 42. If this is performed on the four leaf springs 24, the assembly is completed and the state shown in FIG. 1 is obtained.

  Since the tip of the leaf spring 24 is caught by the inclined surface 32, the sub gear 22 does not come out of the main gear 20. Therefore, the disc spring and the snap ring as in the conventional example are unnecessary.

  When assembling the scissor gear to the other gear (not shown), the sub-gear 22 is twisted relative to the main gear 20 while elastically deforming the leaf spring 24, and the gears of the two gears are aligned with each other. Engage with the mating gear. Thereafter, when the sub gear 22 is released, the sub gear rotates slightly in the counter-rotating direction by the restoring force of the leaf spring 24, and the teeth of the counterpart gear 8 are elastically pinched together with the teeth of the main gear 2. Thereby, the state of zero backlash is realized.

  Next, the operation of the first embodiment will be described with reference to FIG. In FIG. 6, θ is an angle of the inclined surface 32 with respect to a plane perpendicular to the axial direction.

  When the scissor gear is used, the curved surface at the curved distal end portion of the leaf spring 24 and the inclined surface 32 of the sub gear 22 are slidably contacted at the contact portion 36, and the edge-shaped edge including the inclined surface 32 of the sub gear 22 is formed. The blade spring 24 is inserted under the tip of the leaf spring 24. At this time, the elastic force of the leaf spring 24 generates a force F that pushes the inclined surface 32 in the vertical direction. This force F can be broken down into a force f1 in the counter-rotating direction and a force f2 on the main gear side. It should be noted that a force f2 for pushing the sub gear 22 toward the main gear is generated in addition to the force f1 for pushing the sub gear 22 in the counter-rotating direction (force for eliminating backlash). The tilt torque acting on the sub gear 22 can be canceled by the force f2. In addition, the sub gear 22 can be pressed against the main gear 20 by this force f2, and the main gear 20 can be used as a reaction force receiver to prevent the sub gear 22 from tilting.

  When a force is applied to the sub gear 22 from the counterpart gear, the pressing force against the inclined surface 32 of the leaf spring 24 changes according to the magnitude of the force, and the magnitude of the force f2 also changes. Therefore, the magnitude of the force applied to the sub gear 22 toward the main gear can be changed according to the magnitude of the force applied to the sub gear 22, and the optimum force according to the use state can be given to the sub gear. it can.

  In addition, since a plurality of contact portions 36 between the leaf springs 24 and the sub gear 22 are provided in the circumferential direction, preferably at equal intervals, the sub gear 22 can be pressed uniformly in the circumferential direction, and the inclination of the sub gear 22 can be further prevented. .

  As a result of preventing the inclination of the sub gear 22 as described above, the spring force by the leaf spring 24 can be efficiently transmitted in the circumferential direction, a desired backlash reduction effect can be obtained with a relatively small spring force, and the spring can be downsized. become. Since the spring force can be reduced, the meshing sound by the scissor gear at the time of meshing can also be reduced. Furthermore, friction caused by the inclination of the sub gear can be suppressed, and deterioration of backlash reduction performance and wear caused by friction can be suppressed.

  The leaf spring 24 and the inclined surface 32 are preferably designed so as to cancel the torsional torque generated by the force f1 between the meshing gears.

  Since the inclined surface 32 is formed in the opening 34 of the sub-gear 22 and the force by the leaf spring 24 is applied thereto, the force f1 is applied to the sub-gear substantially at the axial position at the center of the tooth width, and the sub-gear is applied. This is advantageous in preventing the inclination of the sub gear based on the difference in the axial position of the force to be applied.

  On the other hand, because the base end edge portion of the leaf spring 24 is engaged with the main gear 20 due to the engagement between the claw portion 40 and the engagement groove 44, the inconvenience that the leaf spring 24 rotates around the center of the bolt is prevented. The

  In the scissor gear according to the conventional example (FIG. 22), the C-shaped spring 7 biases the sub gear 3 in the circumferential direction, and the disc spring 11 biases the sub gear 3 in the axial direction. On the other hand, in the present embodiment, the sub-gear can be urged in both directions by one leaf spring 24, and the number of parts can be reduced or simplified.

Second Embodiment
A scissor gear according to a second embodiment of the present invention is shown in FIGS. 7 shows the scissor gear after assembly, and FIG. 8 shows a part of the details. 9 to 12 are component diagrams of a leaf spring as a sub gear, a main gear, a support member, and an elastic member, respectively. The second embodiment is substantially the same as the first embodiment, and will be described in detail mainly with respect to different parts. The same or corresponding components will be denoted by the same reference numerals as appropriate.

  As shown in FIG. 8, in the present embodiment, a convex portion 50 is provided as a contact portion on the sub gear side. In addition, an opening 52 similar to the above is provided in the vicinity thereof, and a leaf spring 54 as an elastic member fixed to the main gear 20 side on the opening 52 is slidable on the convex portion 50 at the curved end portion. It comes to contact with.

  As shown in FIG. 12, the leaf spring 54 is the same except that the leaf spring 24 and the claw portion 40 of the first embodiment are not provided. The leaf spring 54 is supported by the support member 56 so as to be separated from the main gear 20. The separation distance is substantially equal to the thickness of the sub gear 22 as shown in FIG. The support member 56 has a main gear side bolt part 60 to be fastened to a screw hole 58 (see FIG. 10) of the main gear 20, a spacer part 62 having a larger diameter than the bolt part 60, and the same diameter as the bolt part 60. And a spring side bolt portion 64 for being inserted into the bolt insertion hole 38 (see FIG. 12) of the leaf spring 54.

  When attaching the leaf spring 54, first, the support member 56 is attached to the main gear 20. At this time, the main gear side bolt portion 60 is fastened to the screw hole 58 of the main gear 20, and the support member 56 is installed in the opening 52. Then, the leaf spring 54 is attached to the support member 56. At this time, the spring side bolt part 64 is inserted into the bolt insertion hole 38 of the leaf spring 54, and the nut 66 is fastened to the spring side bolt part 64. Thus, the base end portion of the leaf spring 54 is supported by the support member 56, and the tip end portion of the leaf spring 54 comes into slidable contact with the convex portion 50 of the sub gear.

  As shown in FIG. 13, in the second embodiment as well, as in the first embodiment, a force F that pushes the convex portion 50 obliquely is generated when the scissor gear is used. The direction of this force F is a direction perpendicular to the curved tangent of the tip of the leaf spring 54. This is because, in the illustrated example, the corner portion of the convex portion 50 that comes into contact with the leaf spring 54 has a square cross section as shown in FIG. Since the oblique force F acts on the sub gear in this manner, the force f1 that pushes the sub gear 22 in the counter-rotating direction and the force f2 that pushes the sub gear 22 against the main gear can be simultaneously applied to the sub gear. Therefore, the inclination of the sub gear 22 can be prevented similarly to the first embodiment, and the same effect as described above can be exhibited.

  More preferably, as shown in FIG. 14B, the corner portion of the convex portion 50 with which the leaf spring 54 abuts is obliquely cut out so as to follow the curvature of the leaf spring 54 and the inclined surface 68. Is done. As a result, the contact portion becomes surface contact, and wear of the convex portion 50 and the leaf spring 54 is suppressed. In this case, since the leaf spring 54 comes closer to the convex portion 50, even if the portion 70 between the convex portion 50 and the opening 52 is reduced or deleted in order to prevent unnecessary interference with the leaf spring 54. Good.

  In this embodiment, the opening 52 may be slightly larger than the spacer 62 or may be oval. However, it is necessary to make the size and shape so as not to prevent the relative movement of the sub gear with respect to the main gear.

<Third Embodiment>
A scissor gear according to a third embodiment of the present invention is shown in FIGS. FIG. 15 shows the scissor gear after assembly, and FIG. 16 shows a part of the details. 17 to 20 are component diagrams of the sub gear, the main gear, the rubber block as the elastic member, and the mounting plate, respectively. The third embodiment is also substantially the same as the first embodiment, and will be described in detail mainly with respect to different parts. The same or corresponding components will be denoted by the same reference numerals as appropriate.

  As shown in FIGS. 15 and 16, in the present embodiment, an inclined surface 32 as an abutting portion on the sub-gear side and an opening 34 are provided as in the first embodiment. A rubber block 72 as an elastic member fixed to the main gear 20 is slidably brought into contact with the other inclined surface 32 at the inclined surface 74 of the tip corner portion.

  As shown in FIG. 19, in the rubber block 72, the corner portion on the main gear side of the tip portion of the square cross section is cut out in a chamfered shape, thereby forming an inclined surface 74 that follows the inclined surface 32 on the sub gear side. It is formed. The block 72 is supported in the opening 34 by the support member 76. The support member 76 includes a prismatic boss portion 78 provided on the side surface of the main gear 20, and a mounting plate 82 attached to the top surface of the boss portion 78 with a bolt 80. The mounting plate 82 extends in the direction of the sub gear side inclined surface 32. The block 72 is fixed to the side surface of the mounting plate 82 on the main gear side, and is abutted against or fixed to the boss portion 78.

  Reference numeral 84 in FIG. 18 indicates a screw hole to which the bolt 80 is attached, and reference numeral 86 in FIG. 20 indicates a bolt insertion hole through which the bolt 80 is inserted. As shown in the figure, here, the block 72 is fixed to the boss portion 78 via the mounting plate 82 by two bolts, thereby preventing the block from rotating.

  As shown in FIG. 21, also in the third embodiment, a force F that pushes the inclined surface 32 of the sub gear obliquely is generated when the scissor gear is used, as in the previous embodiment. That is, when the sub gear 22 rotates relative to the main gear 20 in the rotation direction, the block 72 is compressed and deformed according to the relative rotation. At this time, the block 72 is supported from the rear by the boss portion 78 as shown in the figure, and is supported from the side opposite to the main gear by the mounting plate 82, so that the block 72 is prevented from escaping and the force from the sub gear is efficiently transmitted. It can be converted into a deformation. As described above, the oblique force F causes the sub gear to simultaneously apply the force f1 that pushes the sub gear 22 in the counter-rotating direction and the force f2 that pushes the sub gear 22 toward the main gear. Therefore, the inclination of the sub gear 22 can be prevented as in the above embodiment, and the same effect as described above can be exhibited.

  In the present embodiment, the opening 34 is slightly larger than the total size of the block 72 and the boss 78. In any embodiment, the opening is preferably as small as possible. This is to ensure sufficient rigidity of the sub gear.

  In addition, this invention is not limited to the said embodiment, Various improvement and deformation | transformation are possible. For example, the size, shape, number, and the like of the elastic member are preferably determined so that the above-described effects can be maximized. For example, it is possible to reduce the number of elastic members (one is also conceivable) or more. In addition, various methods are conceivable. In the case of an elastic member, for example, a leaf spring, it is also possible to provide a plurality of divided pieces 90 by dividing the vicinity of the abutting portion as indicated by phantom lines in FIG.

  An embodiment in which the first to third embodiments are partially combined is also possible. It is also possible to replace the inclined surface with a curved surface or vice versa.

The scissor gear which concerns on 1st Embodiment of this invention is shown, (a) is a front view, (b) is A-A 'sectional drawing. It is B-B 'sectional drawing of FIG. It is a component figure of the sub gear in 1st Embodiment, (a) is a front view, (b) is C-C 'sectional drawing, (c) is D-D' sectional drawing. It is a component diagram of the main gear in 1st Embodiment, (a) is a front view, (b) is E-E 'sectional drawing, (c) is F-F' sectional drawing. It is a component figure of the leaf | plate spring in 1st Embodiment, (a) is a front view, (b) is a side view. It is a figure for demonstrating the effect | action of 1st Embodiment. The scissor gear which concerns on 2nd Embodiment of this invention is shown, (a) is a front view, (b) is G-G 'sectional drawing. It is H-H 'sectional drawing of FIG. It is a component figure of the sub gear in 2nd Embodiment, (a) is a front view, (b) is J-J 'sectional drawing, (c) is I-I' sectional drawing. It is a component figure of the main gear in 2nd Embodiment, (a) is a front view, (b) is K-K 'sectional drawing. It is component drawing of the support member in 2nd Embodiment. It is a component figure of the leaf | plate spring in 2nd Embodiment, (a) is a front view, (b) is a side view. It is a figure for demonstrating the effect | action of 2nd Embodiment. It is sectional drawing of the convex part vicinity in 2nd Embodiment. The scissor gear which concerns on 3rd Embodiment of this invention is shown, (a) is a front view, (b) is L-L 'sectional drawing. It is M-M 'sectional drawing of FIG. It is a component figure of the sub gear in 3rd Embodiment, (a) is a front view, (b) is O-O 'sectional drawing, (c) is N-N' sectional drawing. It is a component figure of the main gear in 3rd Embodiment, (a) is a front view, (b) is P-P 'sectional drawing. It is a component figure of the rubber block in 3rd Embodiment, (a) is a front view, (b) is Q-Q 'sectional drawing. It is a component figure of the mounting plate in 3rd Embodiment. It is a figure for demonstrating the effect | action of 3rd Embodiment. It is a disassembled perspective view of the scissor gear which concerns on a prior art example. It is sectional drawing which shows the assembly | attachment state of the scissor gear which concerns on a prior art example. It is an enlarged view which shows the meshing part vicinity of a scissor gear.

Explanation of symbols

20 Main gear 22 Sub gear 24 Leaf spring 36 Abutting portion 32 Inclined surface 34, 52 Opening portion 46 Bending portion 50 Protruding portion 56 Support member 68 Inclining surface of convex portion 72 Rubber block 74 Inclining surface of rubber block

Claims (5)

A main gear, a sub-gear having the same tooth shape and the same number of teeth as the main gear, coaxially and relatively rotatable next to the main gear, and an elastic member fixed to the main gear to urge the sub-gear in the circumferential direction relative to the main gear With
A contact portion is provided for slidably contacting the sub gear and the elastic member, and at least one of the contact portions is formed of an inclined surface or a curved surface, thereby deforming the elastic member. A scissor gear characterized in that the sub gear is sometimes biased simultaneously in the circumferential direction and in the axial direction toward the main gear.   The scissor gear according to claim 1, wherein the elastic member is a leaf spring.   An opening is provided through the side surface of the sub-gear, the leaf spring is positioned in the opening and fixed to the main gear, and an inclination that forms a contact portion on the sub-gear side at one end edge of the opening The scissor gear according to claim 2, wherein a surface is formed and a distal end portion of the leaf spring is curved so as to follow the inclined surface to form a contact portion of the elastic member.   A convex portion that forms a contact portion on the sub gear side is provided on the side surface portion of the sub gear, and an opening portion is provided in close proximity to the convex portion and penetrating the side surface of the sub gear. A support member for fixing the leaf spring away from the main gear is provided, and a distal end portion of the leaf spring is bent so as to be slidable with respect to the convex portion to form a contact portion of the elastic member. Item 3. The scissor gear according to item 2. The scissor gear according to claim 4, wherein a contact portion of the convex portion with the leaf spring is an inclined surface that follows the curvature of the leaf spring.

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