JPS61171959A - Back lashless scissors gear - Google Patents

Abstract

PURPOSE:To enable incorporation of gears with a normal tool by using a standardized temporary clamping bolt and storing energy and releasing a scissors spring by changing relative angle position of a main gear and a sub gear. CONSTITUTION:A scissors spring 16 is disposed almost coaxially between a main gear 12 and sub gear 14 to constitute a scissors gear with a circlip type spring having a first and a second end portions. The first end portion is engaged with the main gear 12 and the second end portion is engaged with the sub gear 14. A screw hole 40 is provided on the main gear 12 or the sub gear 14, and a temporary clamping bolt 42 is made to screw in the second or the first end portion. And a means 34 engaging with a tip of the temporary clamping bolt and displacing the second or the first end portion in the circumferential direction is provided on the scissors spring 16. By this constitution, gears can be incorporated only with a normal tool.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is aimed at suppressing gear rattling or noise by eliminating backlash (back pain) of a pair of transmission gears that engage with each other. This invention relates to backlash-less scissor gears used in Such a scissor gear can be used, for example, as a transmission gear for a valve train of an automobile engine, but the present invention is not limited to such an application.

[Conventional technology and problems]

In order to prevent noise in transmission gear devices, it is well known to use scissor gears to eliminate backlash (for example, Utility Model Publication No. 48-2947, Utility Model Publication No. 48-34438).
No., Utility Model No. 55-158349, Utility Model No. 56-160
Publication No. 351). The backlash-less scissor gear consists of a main gear that meshes with an opposing gear and primarily contributes to power transmission, a sub-gear that also meshes with the opposing gear and has the same gear profile as the main gear, and a scissor spring. The main gear and the sub gear are spring-biased in the direction of relative rotation, and the teeth of the opposing gear are sandwiched between the teeth of the main gear and the teeth of the sub gear, thereby eliminating backlash in the gear train.

In order to assemble a scissor gear to an opposing gear when assembling or repairing a transmission gear device, rotational torque is applied to the main gear and sub gear in advance to cause them to rotate relative to each other, thereby accumulating energy in the scissor spring and maintaining this relative rotation state. After the main and sub gears are brought into engagement with the opposing gear while maintaining the torque, the torque must be released to allow the spring force to develop.

Therefore, the assembly process requires a step of relatively rotating the main gear and the sub gear against the spring force, and a step of maintaining this relative rotation state.

In order to implement these steps, various efforts have been made in the past. For example, Japanese Patent Application No. 59-092976, filed on May 1, 1980, proposes a system in which the main and sub gears are rotated relative to each other using a special tool.

This method has the following drawbacks. First, it requires special tools. This means that when scissor gears are used in automobile engines, special tools must be distributed to all the car repair shops and repair shops. This results in an increase in vehicle prices and repair costs. Second, in order to use this special tool, it is necessary to use a jig to fix the rotating shaft (for example, a camshaft) on which the scissor gear is attached, which requires additional space and reduces work efficiency.

[Purpose of the invention]

An object of the present invention is to provide a scissor gear that can be assembled in a simple manner using only standardized standard tools and materials without using special tools.

[Summary of Means for Solving the Problems] In the scissor gear of the present invention, the scissor spring is composed of a circlip type spring, and this spring has a first end that is locked to the main gear and is locked to the sub gear. and a second end.

This spring is arranged substantially coaxially between the main gear and the sub gear. The main or sub gear is provided with a through threaded hole at a position axially aligned with the second end or the first end of the spring in the free state, into which a standard bolt is screwed. It is now possible to enter. This bolt is used as a temporary tightening bolt. The second or first end of the spring is provided with means, for example of a pattern.

Because of this configuration, when a temporary tightening bolt is screwed into the tapped hole, the tip of the bolt engages with the pattern and displaces the spring end in the circumferential direction, causing the main gear and sub gear to move relative to each other. The spring is charged at the same time as it rotates.

If the scissor gear is assembled to the opposing gear in this state and the temporary tightening bolt is removed, the teeth of the opposing gear will be sandwiched between the teeth of the main gear and the sub gear due to the return force of the spring, eliminating backlash.

In the scissor gear of the present invention, the main gear and sub gear can be rotated relative to each other and the spring can be accumulated or released simply by tightening or loosening the temporary tightening bolts. Since it can be operated using only standard tools such as a spanner, no special tools are required when assembling the scissor gear.

〔Example〕

Next, the present invention will be explained in detail with reference to the accompanying drawings.

As shown in FIG. 1, the scissor gear 10 of the present invention is composed of a main gear 12, a sub gear 14, and a scissor spring 16. As is well known, the gears 12 and 14 have the same gear profile and have teeth 18, 20 formed at a predetermined pitch on their respective outer peripheries. The gears 12 and 14 are attached to the driving or driven rotating shaft 22 during use, the main gear 12 is fixed to the rotating shaft 22 by a key or other means, and the sub gear 14 is connected to the main gear 12 and the rotating shaft 22.
It is attached to the rotating shaft 22 so as to be rotatable relative to the rotary shaft 22, and is regulated in the axial direction by a circlip or the like. A spring chamber 24 is formed between the gears 12 and 14 using a recessed portion of the main gear 12, and a scissor spring 16 is housed in the spring chamber 24.

The spring 16 has a circlip shape as shown in FIG. 2, and includes a partially annular body portion 26, a first end portion 28, and a second end portion 30. First end 28 is bent at right angles to the plane of body portion 26 . The second end 30 is bent in the opposite direction from the first end 28 through the slope 32 . A surface 34 of the inclined portion 32 constitutes a pattern, and this covered surface 34 is inclined in the circumferential direction of the main body portion 26 at a predetermined angle θ with respect to the spring axis.

As shown in FIG. 1, the main gear 12 and the sub gear 14
There is a through hole or notch 36, 3B for hanging the spring.
are provided, respectively, and the first and second ends 2B, 30 of the spring 16 are fitted and latched within the through holes 36, 3B, respectively. In FIG. 1, the end portions 28, 3
0 is engaged in the through holes 36 and 3B, and the gears 12 and 14 are rotated relative to each other so that the spring 16 is in a freely relaxed state.

The main gear 12 is provided with a screw hole 40 at a position opposite to the pattern 34 when the spring 16 is in the freely relaxed state. This screw hole has an arbitrary normalization gFLf, knee; .

There is.

Next, to explain how to assemble this scissor gear, as shown in FIG.
The main gear 12 and the sub gear 14 are mounted on the rotating shaft 22 with the gears 0 engaged with the locking holes 36 and 38, and the main gear 12 is fixed with a key.

The sub-gear 14 uses a circlip to prevent axial movement. Next, when the temporarily tightening bolt 42 is screwed into the screw hole 40 using an arbitrary tool such as a spanner or a wrench, the bolt moves forward in the direction of arrow F in FIG. 3, and its tip abuts against the pattern 34. Since the cover surface 34 is inclined at an angle θ with respect to the axis of the bolt 42, when the bolt 42 is further screwed in, the second part of the spring 16 is
@ portion 30 is displaced in the circumferential direction indicated by arrow E in FIG. Gear 12, 14
If an alignment mark is provided on the outer circumferential surface of the holder, the relative angular position of the holder can be visually checked, and the angular position can be brought to the desired angular position. In this state, as shown in FIG.
When the teeth of the opposing gear 44 are engaged with the teeth of the main gear 12 and the sub gear 14 and the temporary tightening bolt 42 is removed, the spring 16 is contracted, so the teeth of the opposing gear 44 are engaged with the teeth of the main gear 12.
8 and the teeth 20 of the sub gear 14, and the backlash B is eliminated.

In the above embodiment, the main gear 12 is provided with a threaded hole for the temporary tightening bolt, but it goes without saying that the sub-gear 14 may be provided with a threaded hole and the first end portion 28 of the spring may be provided with a covered surface. stomach. Further, as a modification, instead of the planar covering surface 34, the end of the spring may be rounded or curved.

[Effects of the Invention] As described above, the scissor gear of the present invention uses a standardized temporary tightening bolt to change the relative angular position between the main gear and the sub-gear, so that the scissor spring can be loaded or released. Gears can be assembled reliably and easily using only standard tools without the need for special tools.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the scissor gear of the present invention, with the rotation axis indicated by a chain line, and Fig. 2 is a perspective view of the scissor spring.
FIG. 3 shows a part of the temporary tightening bolt and scissor spring as seen in the direction of arrow m in FIG. 2, and FIG. 4 is a partial view showing the engaged state of the scissor gear and the opposing gear. 10... Scissor gear, 12... Main gear, 14
...Sub gear, 16...Scissor spring, 22
...Rotating shaft, 28...Spring first end, 30.
...Spring second end, 32...Spring inclined portion, 34...Covered surface, 40...
...Main gear screw hole, 42...temporary tightening bolt. Figure 1 Figure 2

Claims (1)

[Claims] 1. A main gear fixed to a rotating shaft, and a main gear having the same gear profile as the main gear and mounted on the rotating shaft coaxially and adjacent to the main gear so as to be rotatable relative to the rotating shaft and the main gear. A backlash-less scissor gear comprising: a sub-gear; and a scissor spring that elastically biases the main gear and the sub-gear in opposing rotational directions, wherein the scissor spring is substantially coaxially disposed between the main gear and the sub-gear. a circlip-shaped spring disposed and having first and second ends, the first end of the spring engages the main gear, the second end engages the sub-gear, and the spring engages the main gear or the sub-gear; A screw hole passing through in the axial direction is provided at a position aligned in the axial direction with the second end or the first end of the spring in a free state, and a temporary tightening bolt is inserted into the screw hole at the second end or the first end. The second end or the first end of the spring is configured such that when the temporary tightening bolt is screwed into the screw hole, the second end engages with the tip of the temporary tightening bolt. 1. A backlash-less scissor gear, characterized in that it is provided with means for displacing the first end or the first end in the circumferential direction. 2. The means comprises a wedge surface inclined in the circumferential direction of the spring with respect to the axis of the temporary tightening bolt.
Scissor gear described in section. 3. The scissor gear according to claim 1, wherein alignment marks are provided on the outer circumferential surfaces of the main gear and the sub gear to display a desired relative rotation angle between the main gear and the sub gear.