JP2010096263A - Scissor gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scissor gear for improving the freedom of the spring strength of a spring member and also improving the lubricating performance of the spring member by adopting structure using the spring member arranged outside for giving a main gear and a sub gear energizing force required to clamp the other gear. <P>SOLUTION: The scissor gear includes the spring member 25 arranged at a side of the sub gear 20 at the opposite side to the main gear 10 for outputting an energizing force to clamp the other gear 6. Thus, the scissor gear increases the freedom of the size of the spring member and the freedom of the spring strength of the spring member. Furthermore, lubricating oil is easily supplied from the outside therein to improve the lubricating performance of the spring member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a scissor gear that meshes with a mating gear while eliminating backlash.

In transmission systems that transmit rotational torque by meshing gears, such as automobile engines and transmissions, a scissor gear is used on one side of the gear to transmit rotational torque while eliminating backlash between gear teeth. It is being carried out.
A scissor gear used in such a transmission system has a main gear having a tooth portion on the outer peripheral portion and a boss portion on an axial center portion, and is inserted (coaxially) in parallel to the side portion of the main gear by being inserted into the outer peripheral surface of the boss portion Sub-gear (having the same number of teeth as the main gear) and a spring member that sandwiches the main gear and the sub-gear against the mating gear. The teeth of the mating gear are used as the teeth of the main gear. And the tooth portion of the sub gear so that the meshing with the mating gear is performed without backlash.

The scissor gear generally uses a structure in which a spring member is accommodated between the main gear and the sub gear. In many cases, as disclosed in Patent Document 1, an annular spring chamber is formed on the side of the main gear following the boss portion, and a spring member, for example, a U-shaped spring member is accommodated in the spring chamber. Engage one end of the spring member with the side of the sub gear, engage the other end with the side of the main gear, and apply a biasing force to sandwich the teeth of the mating gear between the main gear and the sub gear. The structure given is used.
JP 2006-77826 A

However, in the structure in which the spring member is provided between the main gear and the sub gear, the size of the spring member is considerably limited because of the convenience of accommodating the spring member inside the teeth of the main gear and the sub gear. For this reason, it is difficult to enlarge the spring member, and it is difficult to secure a spring strength suitable for the counterpart gear.
Explaining this point, the degree of freedom of the spring strength of the spring member is required to secure a spring constant suitable for the mating gear. The spring strength can be easily set by increasing the outer shape of the spring member. However, since the spring member is accommodated between the main gear and the sub gear, the degree of freedom is low because of the size restriction. For this reason, it is difficult to secure an effective scissor gear at an application location where a large torque fluctuation is likely to occur, such as an engine or a transmission.

In addition, the spring member of the scissor gear is easily worn to apply the urging force to the main gear and sub gear, and lubrication with lubricating oil is required to prevent this. Lubrication is difficult to expect, and there are also difficulties in terms of lubricity.
Accordingly, an object of the present invention is to adopt a structure in which the urging force necessary for pinching the mating gear is applied to the main gear and the sub gear by a spring member arranged on the outside, and the degree of freedom of the spring strength of the spring member is improved. An object of the present invention is to provide a scissor gear having improved lubricity of members.

In order to achieve the above object, the invention according to claim 1 outputs a biasing force for pinching the mating gear to the side portion of the sub gear and the main gear arranged in parallel to the side of the sub gear opposite to the main gear. A scissor gear with components is used.
The structure that gives the urging force necessary to pinch the mating gear from the spring member arranged outside the sub gear has significantly fewer obstacles that limit the size of the spring member than the structure that houses the spring member between the main gear and the sub gear. The degree of freedom of the size of the spring member is increased. For this reason, the freedom degree of the spring strength of a spring member is raised. In addition, since the spring member is on the outside, the supply of lubricating oil is easily received from the outside, the friction due to contact is reduced, and a stable urging force can be obtained.
The invention according to claim 2 is an engagement portion in which one end portion of the pair of end portions of the spring member is engaged with the sub gear and the other end portion is engaged with the main gear. The power is transmitted to the main gear and the sub gear, and a fixing portion is provided that restricts the sub gear and the main gear from separating in the gear axis direction.

The invention described in claim 3 uses a U-shaped spring member arranged around the boss portion for the spring member so that each portion can be a simple structure, and the outer periphery of the boss portion of the main gear as the fixed portion. An annular groove portion that fits a spring portion around the boss portion of the U-shaped spring member formed along the surface was used.
According to a fourth aspect of the present invention, there is provided a notch portion into which the U-shaped spring member can be inserted on the bottom surface of the annular groove portion so that the U-shaped spring member having increased spring strength can be easily assembled to the annular groove portion. It was decided to form.

  According to the first aspect of the present invention, the spring member disposed outside the sub gear provides a biasing force necessary for sandwiching the mating gear. Therefore, the spring member is larger than the structure in which the spring member is accommodated between the main gear and the sub gear. Obstacles that limit the height are greatly reduced, and the degree of freedom in setting the size of the spring member is increased. For this reason, the freedom degree of the spring strength of a spring member can be raised, and the scissors gear with the spring constant suitable for the other party gear can be obtained easily.

In addition, it becomes easier to supply the lubricating oil from the outside, the lubricity of the spring member can be improved, friction due to contact is reduced, and a stable scissor effect is obtained by a stable urging force.
According to the second aspect of the present invention, the sub gear and the main gear are not separated from each other in the gear axial direction, and the meshing tooth width between the scissor gear and the mating gear can be obtained stably, so that gear wear does not occur. Moreover, the effect of the scissor gear can be obtained stably.

  According to the invention of claim 3, the structure of each part of the scissor gear is simplified, and a more simplified scissor gear can be provided. In particular, in the structure in which the U-shaped spring member is fixed by the groove portion of the boss portion, the spring member also serves as a member for pressing the sub gear against the main gear. That is, in the structure in which the spring member is accommodated between the main gear and the sub gear, when the spring member is deformed, the deformation of the spring member itself causes the behavior of separating the sub gear from the main gear. Although it is necessary to provide a spring member, if the U-shaped spring member is fixed to the outside of the sub gear with a groove, the spring member's deformation causes the sub gear to be pressed against the main gear. It becomes. Thereby, the number of parts can be reduced and the scissor gear can be simplified. In addition, since the spring member is on the outside, the spring member can be separately fixed without using any parts, so that the number of parts can be further reduced and the scissor gear can be further simplified.

  According to the fourth aspect of the present invention, when a U-shaped spring member having high spring strength is adopted by setting with the mating gear, the spring member can be easily assembled in the annular groove. .

Hereinafter, the present invention will be described based on an embodiment shown in FIGS.
FIG. 1 shows, for example, the structure around the camshaft end of a reciprocating engine. In FIG. 1, 1 is a cylinder head, 2 is a camshaft that is rotatably disposed above the cylinder head 1, 3 Is a cover provided to cover the upper part of the cylinder head 1.
A scissor gear 5 that is an essential part of the present invention is assembled to the end of the camshaft 2. The scissor gear 5 is engaged with a driven gear 6 that is a counterpart gear, and a shaft output from a crankshaft (not shown) is transmitted to the camshaft 2.

2 and 3 show a cross section of the scissor gear 5 incorporated in the driving force transmission path of the camshaft 5. FIG. 4A shows the appearance of a single piece of the scissor gear 5 together with a detailed view, and FIG. 5 shows an exploded view of the scissor gear 5.
The structure of the scissor gear 5 will be described with reference to FIGS. 2 to 5. In FIG. 2, 10 is a main gear and 20 is a sub gear. As shown in FIG. 5, for example, the main gear 10 has a large number of teeth 12 formed on the outer periphery of a disk-shaped main body 11, and a short cylindrical boss 13 is formed on one axial center of the main body 11. It has a formed structure. The end of the boss 13 protruding from the main body 11 and the end of the camshaft 2 are fastened by a bolt member 16 (FIG. 2). For this fastening, a recess 14 into which the camshaft end is fitted is formed at the end of the boss 12, and a hole 15 through which the bolt member 16 is inserted is formed at the center of the boss 13.

  The sub gear 20 is a component that is coaxially arranged in parallel on the side of the main gear 10 as shown in FIGS. 1, 2, and 4 (a). That is, as shown in FIG. 3, the sub-gear 20 has a tooth portion 21 having the same number of teeth as that of the main gear 10 on the outer peripheral portion, and a hole portion 22 that can be inserted into and removed from the shaft center portion. Consists of annular gear parts. The sub gear 20 is arranged in parallel to the side portion of the main body portion 11 of the main gear 10 by inserting the shaft center portion (hole portion 22) into the outer peripheral surface of the boss portion 13 of the main gear 10 so as to be rotatable.

  As shown in FIGS. 1, 2, and 4, a spring member 25 is provided on the outer side which is the side of the sub gear 20 opposite to the main gear 10. The spring member 25 is a component that generates an urging force for pinching the tooth portion of the mating gear, here the tooth portion 6a of the driven gear 6 (the mating gear). For the spring member 25, a spring member having a U-shaped outer shape such as a snap ring, which is assembled around the boss portion 13, is used. The spring member 25 is configured by a member having an arc portion 27 disposed around the boss portion 12 and a pair of end portions 28 extending from both sides of the arc portion 27 to the outer peripheral side of the sub gear 20. A pair of engaging recesses 29 are formed at each end 28 of the spring member 25.

  Each end portion 28 of the spring member 25 is engaged with the main gear 10 and the sub gear 20, respectively. In this engagement structure (corresponding to the engagement portion of the present application), for example, an engagement recess 29 at one end of the spring member 25 is engaged with a pin member 31 a protruding from a predetermined position on the outer side of the sub gear 20. The engaging recess 29 at the other end is penetrated, for example, from a predetermined position on the side of the main gear 10 adjacent to the sub-gear 20 through the movable range regulating through-hole, for example, the through hole 32 formed in the sub-gear 20. Then, a structure for engaging with the protruding pin member 31b is used. Of course, the through portion may be a notched portion instead of the through hole 32. The pin members 31a and 31b are attached to the gears 10 and 20 by press fitting. From this engagement structure, an urging force generated by the spring member 25, that is, an urging force that sandwiches the mating gear is output from each end portion 28 to the main gear 10 and the sub gear 20.

  Further, the through hole 32 is set to a size that allows the end portions 28 to be assembled in a slightly expanded state. With the pre-spring load applied, as shown in FIG. 4B, the main gear 10 and the sub gear 20 are connected to each other. The tooth trace is positioned at a predetermined position. The main gear 10 and the sub gear 20 urged by the spring member 25 sandwich the tooth portion 6a of the driven gear 6 that is the counterpart gear. Specifically, the teeth of the main gear 10 and the teeth of the sub gear 20 are shifted (displaced) in the direction in which the spring member 25 expands, and the spring member 25 is deformed in the direction in which the spring member 25 expands. It is sandwiched between both the 10 tooth portions 12 and the tooth portion 21 of the sub gear 20. Thereby, as shown in FIG. 3, the scissor gear 6 meshes with the driven gear 6 while the backlash is eliminated. The through-hole 32 has a size that allows at least the main gear 10 and the sub gear 20 to be assembled with respect to the mating gear.

  As shown in FIGS. 1, 2, and 4 (a), the spring member 25 that applies the urging force to the main gear 10 and the sub gear 20 is fixed to the main gear 10 so as not to drop off at the fixing portion 35. For example, as shown in FIGS. 5 and 6, the fixing portion 35 has a structure in which an annular groove portion 36 is formed on the outer peripheral surface of the boss portion 13, and is arranged around the boss portion 13 in the groove portion 36. By fitting and engaging the spring portion of the spring member 25, specifically, the inner peripheral portion of the arc portion 27, the spring member 25 is fixed so as not to drop off.

  Here, when the spring member 25 is unfolded, the arc portion 27 is deformed in a direction to be squeezed. Therefore, the swaying deformation that occurs in the arc portion 27 plays a role of pressing the sub gear 20 against the main gear 10. That is, only by fixing the spring member 25, the sub gear 20 is pressed against the main gear 10 by the deformation of the spring member 25 accompanying the generation of the urging force, and the close state of the sub gear 20 and the main gear 10 is maintained. That is, the sub gear 20 is restricted so as not to be separated from the main gear 10. Thus, the behavior of the sub gear 20 separating from the main gear 10 is suppressed.

  Further, as shown in FIGS. 6 and 7, for example, a pair of notches 37 are formed on both sides of the annular bottom surface on the bottom surface of the annular groove portion 36. The notch 37 is cut out by a parallel surface. The space between the notches 37 is formed corresponding to the distance between the ends of the spring member 25 so that the spring member 25 can be easily fitted into the groove 36 from the opening side. In particular, the notch portion 37 is formed at a point that is in phase with the point where the pin members 31 a and 31 b are located, and the spring member 25 is assembled so as not to drop off from the main gear 10. That is, when the spring member 25 is assembled (only the pin member 31a is assembled by press-fitting, and the pin member 31b is still before press-fitting), the spring member 25 is inserted into the groove portion through the notch portion 37 as shown in FIGS. 36, and then the spring member 25 is rotated in the groove 36 so that the engagement recess 29 on one side is engaged with the pin member 31a of the sub gear 20, and the remaining engagement recess 29 is inserted into the through hole of the sub gear 20. After that, the pin member 31b is press-fitted into the sub gear 20 through the engaging recess 29 and the through hole 32, so that the spring member 25 is assembled so as not to drop out of the groove 36 as shown in FIG. Stick (with pre-spring load).

The scissor gear 5 configured as described above is configured such that the tooth portion 12 of the main gear 10 and the tooth portion 21 of the sub gear 20 are driven to the driven gear 6 by the urging force applied from the spring member 25 assembled to the outer side as shown in FIGS. The rotational torque transmitted from the driven gear 20 is transmitted to the camshaft 2 while being sandwiched from both sides of the tooth portion 6a.
The scissor gear 5 provided with the spring member 25 on the outside of the sub-gear 20 has few obstacles that restrict the size of the spring member 25, and the outer shape of the spring member 25 can be enlarged to the vicinity of the tooth portion 6b. Compared to the structure in which the spring member is accommodated between the sub gears, the spring member 25 having a significantly larger outer shape can be employed. Thereby, the freedom degree of the setting of the magnitude | size of the spring member 25 increases, the freedom degree of a spring strength can be raised significantly, and the scissor gear 5 with the spring spring constant suitable for the other party gear can be ensured easily. In particular, when the tooth width of the scissor gear 5 is made larger than that of the mating gear as shown in FIG. 2 and the spring member 25 is disposed at a point retracted from the position where the mating gear meshes, the tooth portion as shown in FIG. The spring member 25 having a large outer shape in which the arc portion 27 is arranged near the tip of 6b can be adopted, and the design flexibility of the scissor gear 25 is further enhanced.

  In addition, when the spring member 25 is provided on the outside, the spring member 25 also serves as a member that presses the sub gear 20 against the main gear 10, so that a separate spring member for pressing the sub gear becomes unnecessary. That is, in the case of a structure in which the spring member is accommodated between the main gear and the sub gear, if the spring member is deformed, the deformation of the spring member itself causes a behavior of separating the sub gear from the main gear. Although it is necessary to provide a spring member, if the U-shaped spring member 25 is fixed outside the sub-gear 20, the resulting deformation of the spring member 25 functions to press the sub-gear 20 against the main gear 10. A member becomes unnecessary. Thereby, the number of parts can be reduced and the scissor gear 5 can be simplified.

  Further, since the spring member 25 is on the outside, it is easy to receive the supply of lubricating oil from the outside, the lubricity of the spring member 25 can be improved, and wear of the contact portion can be easily prevented. Further, friction due to contact with the scissors gear 5 and the groove 36 of the main gear 10 is reduced, and a stable scissors effect can be obtained by a stable urging force. In particular, as shown in FIG. 1, the scissors gear 25 is suitable for use in an environment where splashes of lubricating oil fly like the inside of the cover 3.

  If the spring member 25 is fixed by the groove portion 36 formed in the boss portion 13, the spring member 25 can be fixed without using a separate component, and the number of parts of the scissor gear 5 can be further reduced. In particular, when a U-shaped spring member 25 is used and each end portion of the spring member 25 has a pin structure and engages with the main gear 10 and the sub gear 20, the structure of each portion is simplified, and the scissor gear 5 can be further simplified.

In addition, when the notch portion 37 that facilitates insertion of the U-shaped spring member 25 is provided on the bottom surface of the groove portion 36, the spring member 25 having high spring strength (difficult to spread) is adopted by setting with the counterpart gear. Even in this case, the spring member 25 can be easily assembled in the groove portion, and the assemblability of the scissor gear 5 can be secured.
Note that the present invention is not limited to one embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, in one embodiment, the spring member is engaged with the main gear by using a pin member protruding from the main gear. However, if the simplification of the structure is not considered, for example, the engagement member protruding from the outer peripheral surface of the boss portion may be used. A structure may be adopted in which an urging force is applied to the end portion to sandwich the mating gear, or another engagement structure may be used. If the simplification of the structure is not considered, the spring member may be a toggle spring instead of the U-shaped spring member. In one embodiment, the scissor gear of the present invention is applied to a gear part that transmits driving force to the camshaft of a reciprocating engine. However, the present invention is not limited to this, and other parts and gear parts of other power transmission paths are used. You may apply to.

The perspective view which shows the engine part to which the scissor gear which concerns on one Embodiment of this invention was applied. Sectional drawing which follows the AA line in FIG. Sectional drawing which shows the gear meshing in the B section in FIG. (A) is a perspective view which shows the external appearance of scissors gear single item, (b) is sectional drawing which shows the tooth | gear part of the main gear of a scissor gear, and a sub gear. The disassembled perspective view of a scissor gear. The perspective view explaining when incorporating a spring member. Similarly sectional drawing. Sectional drawing when finishing assembling the spring member.

Explanation of symbols

5 Scissor gear 6 Driven gear (opposite gear)
DESCRIPTION OF SYMBOLS 10 Main gear 13 Boss part 20 Sub gear 25 Spring member 28 End part 31a, 31b Pin member (engagement part)
36 Groove (fixed part)
37 Notch

Claims (4)

A main gear having a boss at the shaft center;
A sub-gear having the same number of teeth as the main gear, which is inserted into the outer peripheral portion of the boss portion and arranged in parallel to the side portion of the main gear;
A scissor gear comprising: a spring member that is disposed on a side portion of the sub gear opposite to the main gear and outputs a biasing force for clamping the mating gear from a pair of end portions. One end of the pair of end portions of the spring member is engaged with the sub gear, the other end is engaged with the main gear, and the biasing force of the spring member is applied to the main gear and the sub gear. An engaging part to convey;
The scissor gear according to claim 1, further comprising: a fixing portion that restricts the sub gear and the main gear so as not to be separated in the gear axis direction. The spring member is composed of a U-shaped spring member disposed around the boss portion,
The engaging portion engages one end of the spring member with the sub gear, and engages the other end with a main gear adjacent to the sub gear,
The fixed portion is formed along an outer peripheral surface of a boss portion of the main gear, and is constituted by an annular groove portion into which a spring portion arranged around the boss portion of the U-shaped spring member is fitted. The scissor gear according to claim 2.   4. The scissor gear according to claim 3, wherein the annular groove portion has a notch portion into which a U-shaped spring member can be inserted in an annular bottom surface of the groove portion.

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