JPH09152016A - Jg for inphase setting for scissors gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a jig which can reduce the number of assembly processes by eliminating the need for high-accuracy machining. SOLUTION: In a scissors gear 4, in which a subsidiary gear 3 made to overlap with a main gear 2 secured to a rotating shaft 1 is energized in a predetermined direction of rotation, this jig 8 is used for setting the gears into phase by making the toothed surfaces 2b, 3b of the gears 2, 3 coincide with each other. The rotating shaft 1 includes a screw means 9 engaged therewith in such a way as to freely move in the radial direction of the shaft 1 and an inclined member 10 provided at the screw means 9 to press the subsidiary gear 3 in the opposite direction to energization by means of the movement of the means 9 to rotate the gear 3 as required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scissors gear for removing backlash between gears, and relates to a jig used for phase matching of a main gear and a sub gear of the scissors gear.

[0002]

2. Description of the Related Art In a gear transmission mechanism, a scissors gear is generally used for reducing backlash generated between gears and reducing tooth rattle noise or rattle noise to reduce noise. In particular, this scissors gear is often adopted as one gear of the gear transmission mechanism that connects the cam shafts of the DOHC engine, which effectively reduces noise generated from the engine.

As shown in FIG. 6, the scissors gear is composed of two gears, a main gear b fixed to the camshaft a for mainly transmitting power, and a sub gear c superposed on the main gear b so as to be relatively rotatable. Composed. An urging means by a C-shaped spring d is provided between the main gear b and the sub gear c, whereby the gears b and c are combined in a repulsive direction in a repulsive direction, and the sub gear c has a predetermined size with respect to the main gear b. Is urged in the direction of rotation. More specifically, the spring d, at its both ends, presses the pins e and f driven into the main gear b and the sub gear c, respectively, in a compressed state to give a repulsive force between the gears b and c. g, h
Is a wave washer and a snap ring that regulate the axial position of the sub gear c.

When the scissors gear i is meshed with the other power transmission gear j, the teeth of the main gear b and the sub gear c press the mating teeth in the separating direction between the teeth of the other gear j. , Backlash, that is, the gap is removed.

By the way, when this scissor gear is applied to one camshaft of a DOHC engine, when the both camshafts are assembled to the engine, the main gear and the sub gear of the scissor gear are preliminarily phase-aligned with each other, that is, the tooth surfaces of these gears are in contact with each other. The scissors gear cannot be meshed with the power transmission gear of the other party unless the work of matching is done. In other words, in the scissor gear alone, the teeth of the main gear and the sub gear are out of phase due to the biasing force, so it is necessary to add a forcing force against the biasing force to perform phase matching. If this is not done, abnormal noise may occur due to damage to the tooth surface during assembly. Similarly, at the time of disassembly, the need for such phase matching arises.

Therefore, a proposal for performing this easily and in a short time has already been proposed in JP-A-1-164863 and JP-A-5-2126.
81 publication. In particular, all of these proposals use a dedicated jig to perform phase matching.

[0007]

By the way, in each of these conventional proposals, there is a process of temporarily fixing the main gear and the sub gear with bolts after performing the phase matching by the jig. That is, after the phase adjustment, the main gear and the sub gear are temporarily fixed before the jig is removed so that the main gear and the sub gear do not cause tooth shift due to the biasing force or the repulsive force.

However, in this case, the main gear and the sub gear are penetrated from the lateral direction or the axial direction or formed into a skewered shape and are joined by bolts, so that the bolt holes are formed at the positions where the phases of the gears or the tooth surfaces are aligned. Must be provided accurately, and there is a problem that the cost becomes high due to the demand for processing accuracy. In addition, it is necessary to attach and detach the temporary fixing bolts, which causes an increase in the assembly process.

[0009]

The present invention relates to a scissors gear in which a sub gear superposed on a main gear fixed to a rotary shaft is biased in a predetermined rotation direction,
A jig used when matching the tooth surfaces of the gears with each other, and a screw means that is screwed onto the rotating shaft so as to be movable in the radial direction thereof, and the screw means is provided.
By the movement, the sub gear is pressed in a direction opposite to the urging direction, and an inclined member for appropriately rotating the sub gear is provided.

In this structure, the inclined member moves in the radial direction of the rotary shaft in accordance with the movement of the screw means such as the bolt. Then, at this time, the inclined member presses the sub gear in the direction orthogonal to the moving direction and rotates it in the direction opposite to the urging direction until the tooth surfaces are aligned with each other. Although the phase matching is completed in this way, since the state at the end particularly corresponds to the temporarily fixed state of the sub gear, it can be meshed with the mating gear as it is, and the work can be greatly simplified. Further, since the rotational phase of the sub gear can be freely determined by adjusting the movement amount of the inclined member, any highly accurate machining is unnecessary.

[0011]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

1 and 2 show a jig according to the present invention,
In particular, these show the state before phase matching. The rotary shaft or camshaft 1 shown here is one of the two camshafts of the DOHC engine on the exhaust side,
The remaining intake-side camshaft (not shown) is arranged adjacent to and parallel to the exhaust-side camshaft 1. These camshafts are synchronously rotated via a gear transmission mechanism, and the input is transmitted from the crankshaft to the intake side camshaft via a belt or chain mechanism. Therefore, regarding the relationship between the camshafts, the intake side is the drive side and the exhaust side is the driven side. A cylinder and a piston (not shown) are arranged below these camshafts in the figure.

A scissors gear 4 is provided at one end of the exhaust side camshaft 1, and the scissors gear 4 is mainly composed of a main gear 2 and a sub gear 3 having the same tooth profile. The main gear 2 is completely fixed to the camshaft 1 so as not to be rotatable and axially movable by press fitting or the like. In particular, a pipe portion 5 is formed so as to project on the rear surface of the main gear 2, and the sub gear 3 is attached to the pipe portion 5 and the camshaft 1
It is fitted from the outside in the radial direction so as to be relatively rotatable so as to be sandwiched between the large diameter portion 1a.

However, the relative rotation of the sub gear 3 is
The C-shaped spring 7 housed in the groove 6 of the main gear 2 regulates the pressure to a certain range. This is due to the same structure as described above, that is, in the groove 6, pins (not shown) that are respectively driven into the main gear 2 and the sub gear 3 are also housed. When the pin is separated by the rotation of the sub gear 3 and the spring 7 is compressed, the spring 7 repels the main gear 2 and the sub gear 3 in the reverse rotation direction due to the restoring force, and the sub gear 3 is rotated in a predetermined rotation direction with respect to the main gear 2. Urge to.

On the other hand, the jig 8 for adjusting the phase of the scissors gear 4 has a bolt 9 as a screw means. The bolt 9 is inserted into and supported by a tapered member 10 as an inclined member, and is screwed into a screw hole 11 provided on the outer circumference of the large diameter portion 1 a of the camshaft 1. That is, in the bolt 9, the threaded portion 9a on the lower side or the tip side thereof is screwed into the threaded hole 11 along the radial direction of the camshaft 1, and the shaft portion 9b on the upper side thereof is tapered.
Is rotatably inserted in the insertion hole 12. Insertion hole 12
Has a diameter larger than that of the threaded portion 9a so that the bolt 9 can be inserted and removed. A spring washer 13 and a flat washer 14 are provided between the bolt 9 and the tapered member 10.

The tapered member 10 includes a tapered portion 15 having the insertion hole 12 and the camshaft 1 from the tapered portion 15.
Alternatively, it is integrally configured with the tooth portion 16 extending to the front end side of the engine. The tapered portion 15 is formed in a tapered shape as a whole as shown in FIG. 1, and particularly one side surface thereof forms an inclined surface 17. The inclined surface 17 contacts the pin 18 protruding from the rear side surface of the sub gear 3, and the pin 18 is pressed in the rotational direction by the movement of the tapered member 10, which will be described in detail later. Further, on the rear side surface of the tapered portion 15, when the tapered member 10 is moved, the cam 1 adjacent to the large diameter portion 1a is provided.
A step portion 20 is also formed to prevent interference with 9.

The tooth portion 16 has an extension length that extends above the sub gear 3 and reaches above the main gear 2. The tip portion of the tooth portion 16 has a plurality of teeth 1 projecting downward to mesh with the main gear 2.
0a. Naturally, the tooth 10a has the same tooth shape as the tooth 2a of the main gear 2 (and the tooth 3a of the sub gear 3).

Next, the jig 8 of the present invention having the above construction
The operation will be described.

In the state before the phase alignment shown in FIGS. 1 and 2, the tooth surface 2b of the main gear 2 and the tooth surface 3 of the sub gear 3 are provided.
The position is not coincident with b and the phase is shifted. At this time, the bolt 9 is screwed only up to an appropriate position, and the tapered member 10 has the lower end of the inclined surface 17 of the pin 18
It has stopped in contact with.

When the bolt 9 is tightened from this state, the tapered member 10 moves to the radial center side of the cam shaft 1 and gradually approaches the cam shaft 1.

Then, in accordance with this movement, the inclined surface 17
Slides on the pin 18 and presses the pin 18 in the rotation direction orthogonal to the moving direction of the tapered member 10, and resists the biasing force of the spring 7 to rotate the sub gear 3 in the direction opposite to the biasing direction. . Then, when the tapered member 10 is further moved, as shown in FIGS. 3 and 4, the tooth surfaces 2b and 3b are aligned with each other, and the phase matching is completed.

One particular feature of the jig 8 is that the camshaft 1 can be assembled as it is in the state at the end of this process. That is, in this state, the jig 8 itself is temporarily fixing, and with the jig 8 attached, the camshaft 1 can be placed on the cylinder head and engaged with the gear of the intake side camshaft. it can. In this way, the phase adjustment and the temporary fixing can be performed at the same time and in the same process, whereby the assembly process can be reduced and the work can be made efficient and easy.

Further, at this time, if the phases are slightly shifted so that the meshing is impossible, the phase matching may be performed again as much as necessary until the meshing becomes possible. As described above, the jig 8 is also characterized in that it can be readjusted in the temporarily fixed state.

As shown in FIG. 5, this meshing is performed by a pair of teeth 2a on which the mark 21 of the main gear 2 is engraved.
During this period, the gear teeth 22a of the gear 22 of the intake camshaft are engaged with the teeth 22a.

Further, the jig 8 has the following features. At the time of assembling the engine, the valve timing will be incorrect unless the phase of the camshaft matches the preset value for the phase of the crankshaft. Therefore, here, when the piston of the predetermined cylinder, that is, the # 1 piston located at the foremost end of the engine is at the top dead center, the meshing is performed so that the marks 21 and 23 are aligned based on the crank angle at this time. It is being appreciated.

Particularly, at this time, the jig 8 is mounted on the opposite side (upper side in the figure) of the cylinder as shown in FIGS. 1 to 4, and the movement of the nearby cylinder head, cam shaft, valve spring, etc. is performed. It stands upright without interfering with valve system parts. That is, when the # 1 piston is at the top dead center, the screw hole 11 of the camshaft 1 is positioned so as to face the opposite side of the cylinder.

Therefore, the camshaft 1 can be assembled with the jig 8 still attached, and the jig 8 can be easily readjusted and removed from above. This also makes the work easier.

Especially in an engine with a small valve holding angle,
Since the diameter of the scissors gear and the like is small and there is almost no extra space due to the need for shortening the overall length and reducing the weight, this configuration is very advantageous.

Note that this may be based on the piston positions of other cylinders, or may be based on the bottom dead center position.

Further, the taper member 10 is used for phase matching.
Since it is performed using the inclined surface 17, the rotational phase can be arbitrarily adjusted by adjusting the amount of movement of the bolt 9 or the tapered member 10 in the radial direction, whereby the angle of the inclined surface 17 and the position of the pin 18 are made accurate. Highly accurate processing is not required, and it is possible to reduce the manufacturing cost.

In addition, since the tooth portion 16 meshes with the main gear 2 at the time of phase matching, it is possible to prevent rattling when the tapered member 10 moves, and improve workability. If the tapered member 10 is stable, the tooth portion 16 may be omitted.

Here, in the tapered member 10, the other inclined surface 24 located on the opposite side of the inclined surface 17 is not used in the above case, but this is used for another scissor gear having a reverse biasing direction. It is designed so that it can be used for a wide range of purposes. Further, the rotation phase amount with respect to the moving stroke of the tapered member 10 can be arbitrarily set by changing the angles of the inclined surfaces 17 and 24.

As described above, the present invention is not limited to the above-described embodiment, and various modifications can be made. Instead of the pin 18, a projection may be integrally formed on the sub gear 3 and pressed.

[0034]

The present invention exhibits the following excellent effects.

(1) Since the phase adjustment is performed by moving the inclined member, highly accurate processing is not required and the manufacturing cost can be reduced.

(2) The phase adjustment and the temporary fixing can be performed at the same time and in the same process, and the work can be made efficient and easy by reducing the assembly process.

(3) The camshaft can be assembled with the jig attached, and the work can be further facilitated.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG. 2 showing a state before phase matching of a jig according to the present invention.

FIG. 2 is a half cross-sectional side view showing a state before phase matching of the jig according to the present invention.

FIG. 3 is a sectional view taken along line BB of FIG. 4 showing a state after phase matching of the jig according to the present invention.

FIG. 4 is a half sectional side view showing a state after phase matching of the jig according to the present invention.

FIG. 5 is a partial front view showing a meshed state of gears of a camshaft.

FIG. 6 is a perspective view showing a general scissor gear.

[Explanation of symbols]

 1 camshaft (rotary shaft) 2 main gear 2b, 3b tooth surface 3 sub gear 4 scissors gear 8 jig 9 bolt (screw means) 10 taper member (inclined member) 11 screw hole

Claims (2)

[Claims] 1. A scissors gear in which a sub gear superposed on a main gear fixed to a rotary shaft is biased in a predetermined rotation direction, and is used for phase matching for aligning tooth surfaces of these gears. A jig, which is a screw means that is screwed onto the rotary shaft so as to be movable in the radial direction thereof, and provided on the screw means, and by the movement thereof, the sub gear is pressed in the direction opposite to the urging direction and appropriately rotated. A jig for phase matching of a scissors gear, comprising an inclined member. 2. The rotating shaft is a camshaft of an engine, the camshaft has a screw hole into which the screw means is screwed, and the screw hole is in a state in which the camshaft is assembled to the engine. The scissors gear phase adjusting jig according to claim 1, wherein the jig for facing the phase of the scissors gear is faced on the opposite side of the cylinder when the piston of the predetermined cylinder is at the top dead center or the bottom dead center.