JP2006077786A - Scissors gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scissors gear, improving assembling efficiency and decreasing the number of parts. <P>SOLUTION: This scissors gear includes: a main gear having a predetermined number of teeth; a sub-gear having the same tooth form and number of teeth as the main gear and adjacent to the main gear in the axial direction to mesh with a counter gear together with the main gear; and a spring provided between the main gear and the sub-gear to energize the sub-gear to the main gear in the rotating direction. The main gear has a plurality of first engagement projections separated from each other at equal spaces on the side thereof in the circumferential direction and respectively provided with an internal groove. The sub-gear is composed of an annular outer peripheral part having a plurality of teeth on the outer periphery and an annular inner peripheral part offset at a predetermined distance in the axial direction from the annular outer peripheral part. The sub-gear has a plurality of axial positioning parts having a second engagement projection and a plurality of radial/rotating positioning parts having a third engagement projection and a stopper. When the sub-gear is assembled to the main gear, the axial positioning is achieved by the axial positioning parts, and the radial and rotating direction positioning is achieved by the radial/rotating direction positioning parts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a scissor gear that eliminates backlash with a counterpart gear.

  Conventionally, in a manual transmission for an automobile, for example, a back gear with a first speed drive gear and a second speed drive gear, which are counterpart gears, is provided by attaching a sub gear to a first speed driven gear and a second speed driven gear rotatably mounted on a counter shaft. A scissor gear that eliminates the problem is used.

  Such scissor gears are also used as driving or non-driving gears for devices that produce torque fluctuations such as fuel injection pumps or camshafts of automobile engines.

  Specifically, the scissor gear has a main gear having a predetermined number of teeth, a sub-gear that has the same tooth shape and the same number of teeth as the main gear, is disposed adjacent to the main gear, and meshes with the mating gear together with the main gear, and the sub-gear as the main gear. And a spring biased in the rotational direction.

  And, by holding the grip in the rotational direction by the spring force of the spring and meshing with the mating gear, the teeth of the mating gear are sandwiched between the teeth of the main gear and the sub gear, so that the backlash with the mating gear is eliminated. It has become.

  FIG. 1 is an exploded perspective view of a conventional scissor gear. The main gear 2 has a boss 4 and a plurality of holes 5 for fastening rivets. The sub-gear 6 has a plurality of holes 7 for fastening rivets. A spring 8 is sandwiched between the main gear 2 and the sub-gear 6, and the sub-gear 6 is fastened to the main gear 2 with the rivet 10. I was assembling.

In this scissor gear, the radial direction is positioned by fitting the sub gear 6 to the boss 4 of the main gear 2, and the axial direction and the rotational direction are positioned by the rivet 10.
Japanese Utility Model Publication No. 5-57499 Japanese Utility Model Publication No. 6-20947 Japanese Patent Laid-Open No. 7-19319 JP-A-11-303974 JP 2000-257698 A JP 2001-12581 A JP 2001-12582 A

  In the conventional scissor gear as shown in FIG. 1, the rivet 10 must be caulked while receiving the reaction force of the spring 8, and there is a problem that it is difficult to assemble the scissor gear. Further, it is necessary to use caulking rivets, and there is a problem that the number of parts is large.

  The present invention has been made in view of these points, and an object of the present invention is to provide a scissor gear with improved assemblability and reduced number of parts.

  According to the first aspect of the present invention, a main gear having a predetermined number of teeth, a sub-gear having the same tooth shape and the same number of teeth as the main gear, and adjacent to the main gear in the axial direction and meshing with the mating gear together with the main gear, and the main gear There is provided a scissor gear which is provided between the sub-gear and a spring which urges the sub-gear in the rotational direction with respect to the main gear.

  The main gear has a plurality of first engaging protrusions that are spaced apart at equal intervals in the circumferential direction on one side surface and have inner grooves that protrude in the radial direction, and the sub gear has an annular shape having a plurality of teeth on the outer periphery. An outer peripheral portion and an annular inner peripheral portion offset from the annular outer peripheral portion by a first predetermined distance in the first axial direction.

  The sub gear has a first slit formed in the annular outer peripheral portion in order to avoid interference with the first engagement protrusion of the main gear, and is integrated with the outer periphery of the annular inner peripheral portion facing the first slit. A plurality of axial positioning portions each including a second engaging protrusion formed by offsetting a second predetermined distance larger than the first predetermined distance in the first axial direction from the annular outer peripheral portion.

  The sub gear further includes a second slit formed in the annular outer peripheral portion in order to avoid interference with the first engagement protrusion of the main gear, and integrally with the outer side of the annular inner peripheral portion facing the second slit. A plurality of radial direction and rotational direction positioning portions including third formed protrusions and stoppers are formed.

  When the sub-gear is attached to the main gear, the second engagement protrusion is fitted into the inner groove of the main gear, thereby achieving axial positioning, and the outer periphery of the third engagement protrusion is in contact with the inner periphery of the first engagement protrusion. Positioning in the radial direction is achieved by contact, and positioning in the rotational direction is achieved by the stopper coming into contact with the first engagement protrusion by the biasing force of the spring.

  According to the invention described in claim 2, in the invention described in claim 1, the main gear has a relief portion deeper than the depth of the inner groove between the first engagement protrusions.

  According to the invention described in claim 3, in the invention described in claim 1 or 2, the first slit and the second slit have the same shape.

  According to the first aspect of the present invention, there is provided a scissor gear capable of reducing the number of parts, realizing a light weight, a compact size and a low cost, and further improving the assemblability.

  According to the second aspect of the present invention, since the main gear has the relief portion deeper than the depth of the inner groove between the first engagement protrusions, the axial positioning portion and the radial / rotational direction positioning portion of the sub gear are connected to the main gear. The scissors gear can be easily assembled by attaching the sub gear to the main gear in accordance with the escape portion and rotating the sub gear in a predetermined direction.

  According to the invention described in claim 3, since the first and second slits have the same shape, the productivity of the sub gear is improved.

  Referring to FIG. 2, there is shown a longitudinal sectional view of the periphery of the first gear train and the second gear train of a manual transmission suitable for application of the scissors gear of the present invention. The main shaft 12 and the counter shaft 14 are rotatably attached to a transmission case (not shown).

  The main shaft 12 is selectively connected to an engine crankshaft via a clutch (not shown), and is rotated by the driving force of the engine when the clutch is engaged.

  Between the input shaft 12 and the counter shaft 14, for example, a plurality of transmission gear trains that define each of the first to fifth gears are provided. In FIG. Only the gear train 18 is shown.

  The first-speed gear train 16 includes a drive gear 20 fixedly attached to the input shaft 12 and a driven gear 22 rotatably attached to the counter shaft 14. The drive gear 20 and the driven gear 22 mesh with each other. Yes.

  The second gear train 18 includes a drive gear 24 that is fixedly attached to the input shaft 12 and a driven gear 26 that is rotatably attached to the counter shaft 14. The drive gear 24 and the driven gear 26 mesh with each other. .

  A sub gear 28 is attached to the driven gear 22 of the first gear train 16, and a sub gear 30 is attached to the driven gear 26 of the second gear train 18.

  Switching between the first-speed gear train 16 and the second-speed gear train 18 is achieved by a synchronization mechanism 32 provided on the counter shaft 14 between the first-speed driven gear 22 and the second-speed driven gear 26.

  The synchro mechanism 32 includes a synchro hub 34 that is spline-fitted to the countershaft 14, a synchro sleeve 36 that is spline-fitted on the outer periphery of the synchro hub 34 and has a driven gear 37 for retraction, and two baux rings 38 and 40. .

  Since the sub gears 28 and 30 are respectively attached to the side surfaces of the first speed driven gear 22 and the second speed driven gear 26, backlash with the first speed drive gear 20 and the second speed drive gear 24 that are always meshed can be suppressed. Gear rattling noise caused by engine rotational angular velocity fluctuations can be suppressed.

  Referring to FIG. 3, an exploded perspective view of the scissors gear 42 according to the embodiment of the present invention is shown. FIG. 4 is a perspective view of the scissors gear 42 in the assembled state.

  The scissors gear 42 according to the present embodiment is composed of a main gear 44 and a sub gear 46 attached to the main gear 44 with a spring 48 interposed therebetween, and fastening of rivets or the like conventionally required for attaching the sub gear 46 to the main gear 44 is performed. It is characterized by not using means.

  Referring to FIG. 5, a front view of the main gear 44 of the embodiment of the present invention is shown. 6 is a cross-sectional view taken along line AA of FIG. 5, and FIG. 7 is a rear view of FIG. The main gear 44 has a plurality of teeth 50 on its outer periphery and a plurality of dog teeth 51 for meshing with the sleeve 36 of the synchro mechanism 32 on the back side.

  5 and 6, the main gear 44 has a plurality of first engaging protrusions 52 that are spaced apart at equal intervals in the circumferential direction on the one side surface and have inner grooves 54 that protrude in the radial direction. Have. In the present embodiment, the first engaging protrusions 52 are formed 60 degrees apart in the circumferential direction. Between the adjacent first engaging protrusions 52, a relief portion 56 deeper than the depth of the inner groove 54 is formed.

  Referring to FIG. 8, a front view of the sub gear 46 according to the embodiment of the present invention is shown. 9 is a cross-sectional view taken along line AA in FIG. 8, and FIG. 10 is a cross-sectional view taken along line BB in FIG.

  The sub gear 46 includes an annular outer peripheral portion 46a having a plurality of teeth 60 on the outer periphery, and an annular inner peripheral portion 46b offset from the annular outer peripheral portion 46a by a first predetermined distance, for example, 3.0 mm, in the first axial direction. Composed.

  As shown in FIG. 8, the sub-gear 46 has three axial positioning portions 62 that are 120 degrees apart from each other in the circumferential direction, and 120 in the circumferential direction so as to be disposed between the axial positioning portions 62. Three radial and rotational positioning portions 64 that are spaced apart from each other are provided.

  The axial positioning portion 62 includes a first slit 66 formed in the annular outer peripheral portion 46 a in order to avoid interference with the first engagement protrusion 52 of the main gear 44, and an annular inner peripheral portion facing the first slit 66. From the second engaging protrusion 68 formed integrally with the outer periphery of 46b and offset from the annular outer peripheral portion 46a in the first axial direction by a second predetermined distance larger than the first predetermined distance, for example, 4.6 mm. Composed.

  The radial direction and rotational direction positioning portion 64 faces the second slit 70 formed in the annular outer peripheral portion 46 a in order to avoid interference with the first engagement protrusion 52 of the main gear 44, and the second slit 70. It is comprised from the 3rd engaging protrusion 72 and the stopper 74 which were integrally formed in the outer periphery of the cyclic | annular inner peripheral part 46b.

  As apparent from FIG. 9, the third engagement protrusion 72 and the stopper 74 are formed on the same plane as the annular inner peripheral portion 46 b of the sub gear 46, but the second engagement protrusion of the axial positioning portion 62. 68 is offset in the direction away from the annular outer peripheral portion 46a.

  11A is a plan view of the coil spring 48 in a set state, and FIG. 11B is a front view thereof. The state set here refers to the state of the coil spring that is assembled to the scissors gear 42 as shown in FIG.

  The coil spring 48 has an end portion 48 a that fits into the hole 58 of the main gear 44 and an end portion 48 b that fits into the hole 76 of the sub gear 46. A free state of the coil spring 48 is shown by a two-dot chain line in FIG.

  Next, the procedure for assembling the scissors gear 42 of this embodiment will be described. First, with the coil spring 48 free, its end 48 a is fitted into the hole 58 of the main gear 44, and the end 48 b is fitted into the hole 76 of the sub gear 46.

  From this state, the coil spring 48 is rotated in the extending direction, for example, counterclockwise in FIG. 11A, and the phases of the main gear 44 and the sub gear 46 are matched. That is, the sub gear 46 is rotated against the urging force of the coil spring 48, and the sub 46 is moved until the axial positioning portion 62 and the radial / rotational direction positioning portion 64 of the sub gear 46 exactly coincide with the escape portion 56 of the main gear 44. Rotate.

  From this state, when the sub gear 46 is rotated clockwise while pressing the sub gear 46 against the main gear 44, the second engaging protrusion 68 of the sub gear 46 is formed in the inner groove formed below the first engaging protrusion 52 as shown in FIG. 54. Thereby, positioning of the scissors gear 42 in the axial direction is achieved.

  When the hand is released in this state or the sub gear 46 is further rotated in the clockwise direction, the stopper 74 of the radial / rotating direction positioning portion 64 is moved to the side surface of the first engaging protrusion 52 of the main gear 44 by the urging force of the coil spring 48. The scissors gear 42 is in a set state.

  In this state, as shown by an arrow 78 in FIG. 14, the urging force of the coil spring 48 acts in a direction in which the stopper 74 is pressed against the side surface of the first engagement protrusion 52. Thereby, positioning of the scissors gear 42 in the rotational direction is achieved.

  In this state, the outer periphery of the third engagement protrusion 72 formed on the sub gear 46 contacts the inner periphery of the first engagement protrusion 52 formed on the main gear 44. Thereby, the scissors gear 42 is positioned in the radial direction.

  In the above-described embodiment, the scissors gear of the present invention is applied to the 1st and 2nd driven gears of the manual transmission. However, the present invention is not limited to this example. The present invention can also be applied as a drive gear or a driven gear of a device that generates torque fluctuations such as an injection pump and a camshaft.

It is a disassembled perspective view of the conventional scissor gear. It is a longitudinal cross-sectional view of the 1st gear train and 2nd gear train part of a manual transmission suitable for the present invention to be applied. It is a disassembled perspective view of the scissors gear of embodiment of this invention. It is a perspective view of the state which assembled the scissor gear of embodiment of this invention. It is a front view of a main gear. It is the sectional view on the AA line of FIG. It is a rear view of a main gear. It is a front view of a sub gear. It is the sectional view on the AA line of FIG. It is the BB sectional drawing of FIG. FIG. 11A is a plan view of the coil spring, and FIG. 11B is a front view of the coil spring. It is a perspective view which shows the 1st engagement protrusion part with an inner groove of a main gear. It is a perspective view which shows an axial direction positioning state. It is a perspective view which shows a radial direction and a rotation direction positioning state.

Explanation of symbols

42 Scissor gear 44 Main gear 46 Sub gear 48 Coil spring 52 First engagement protrusion 54 Inner groove 56 Relief part 46a Annular outer peripheral part 46b Annular inner peripheral part 62 Axial positioning part 64 Radial / rotational direction positioning part 66 First slit 68 Second Engaging protrusion 70 Second slit 72 Third engaging protrusion 74 Stopper

Claims (3)

A main gear having a predetermined number of teeth; a sub-gear having the same tooth shape and number of teeth as the main gear; adjacent to the main gear in the axial direction; and meshing with the mating gear together with the main gear; and provided between the main gear and the sub-gear. In the scissors gear provided with a spring that urges the sub gear in the rotational direction with respect to the main gear,
The main gear has a plurality of first engagement protrusions on one side surface that are spaced apart at equal intervals in the circumferential direction and that have respective inner grooves protruding radially.
The sub gear is composed of an annular outer peripheral portion having a plurality of teeth on the outer periphery, and an annular inner peripheral portion offset from the annular outer peripheral portion by a first predetermined distance in the first axial direction.
The sub gear includes a first slit formed in the annular outer peripheral portion to avoid interference with the first engagement protrusion of the main gear, and an outer periphery of the annular inner peripheral portion facing the first slit. And a plurality of axial positioning portions formed of a second engagement protrusion formed integrally with the annular outer peripheral portion and offset by a second predetermined distance larger than the first predetermined distance in the first axial direction. When,
In order to avoid interference with the first engagement protrusion of the main gear, a second slit formed in the annular outer peripheral portion, and integrally with the outer periphery of the annular inner peripheral portion facing the second slit Having a plurality of radial and rotational positioning portions composed of the formed third engaging protrusions and stoppers;
When the sub gear is attached to the main gear, the second engagement protrusion is fitted into the inner groove, thereby achieving axial positioning, and the outer periphery of the third engagement protrusion is the first engagement protrusion. A scissors gear, wherein radial positioning is achieved by abutting on an inner periphery, and rotational positioning is achieved by abutting the stopper against the first engagement protrusion by the biasing force of the spring.   The scissors gear according to claim 1, wherein the main gear has an escape portion deeper than a depth of the inner groove between the first engagement protrusions.   The scissor gear according to claim 1 or 2, wherein the first slit and the second slit have the same shape.

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