JP2835503B2 - Gear set - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a four-cycle engine.
From the crank gear on the crankshaft.
The present invention relates to a gear set for transmitting power to a cam gear on a gear shaft .

[0002]

2. Description of the Related Art When a gear is attached to the outside of a shaft, a retaining ring (snap ring or circlip) is provided at a position adjacent to the fitting surface of the two in the axial direction in order to prevent the gear from slipping off. It is common. A nut may be used instead of a retaining ring, or a shoulder (thick part) may be formed on the shaft. However, the position where these are provided is next to the mating surface, that is, at a point off the mating surface. There is no difference. This point is not limited to the case where the shaft and the gear are fitted together, but is also common when a collar or a cam is attached on the shaft, or when a gear or the like is attached outside the bearing.

However, in reality, there are not a few cases where there is no space for providing a retaining ring, a nut, or the like at a position outside the fitting surface. For example, in a device such as a motorcycle engine, which is also required to be compact while being a multi-functional body with a large number of parts, the purpose is only to prevent the gear etc. to be fitted out from falling out. It is very disadvantageous to use such components. The gear has already become thin due to the arrangement of parts and the like, and the space on the shaft for attaching the gear is also limited, and there are cases where a retaining ring or the like cannot be attached to any outside.

In such a case, conventionally, both parts are fitted by press-fitting (ie, interference fit) or "caulking", or an adhesive is used on a fitting surface of both parts. FIG. 4 shows an outer ring 1 of a bearing (deep groove ball bearing) 10 ′.
1 'on the gear 2 by press-fitting without using a retaining ring, etc.
It is sectional drawing which shows the example which fitted 0 '. In addition, JP-A-3-70870 discloses an example in which a bearing and a housing (casing) are fitted by caulking. According to such a means, there is no need to provide a retaining ring or the like at a position outside the fitting surface for retaining, which is advantageous in terms of space.

[0005]

In order to prevent the gear 20 'from slipping off (or to prevent the gear 20' from slipping in the rotating direction) by press-fitting as shown in FIG. May occur. Since the frictional force between the surfaces based on the pressure input (contact pressure) between the gear 20 ′ and the bearing 10 ′ prevents the gear 20 ′ from coming off, a press fit (tightening) is required between the two. A considerable press-in force must be applied, which deforms the gear 20 'so that it can be pushed out from the inside of the hole (ie the mating surface 20a'). When the gear 20 'is deformed in this manner, the backlash increases because the size of the tooth groove increases, but when the degree increases, the meshing with the counterpart gear (not shown) becomes less smooth. Further, since the same pressure input (the direction is reverse to the above) acts on the bearing 10 ′ as the inner member, the outer ring 11 ′ is deformed, the radial clearance becomes small, and the rotation may not be smooth. is there.
In addition, when the width B and the diameter D of the fitting surfaces 10a 'and 20a' are small, it is necessary to apply a large press force per unit area of each surface, so that the above tendency becomes remarkable.

[0006] Even in the case of using caulking as in the example of the above-mentioned publication, it is necessary to increase the caulking force in order to obtain a sufficient retaining effect, and it is possible to deform or damage a part to be fitted. is there. In addition, it is difficult to effectively apply the adhesive between the mating surfaces using the adhesive on the mating surfaces (they are scraped off during the mating process).
Therefore, it is difficult to expect strong power for retaining.

An object of the present invention is to provide an engine having a thin structure.
In the bearing and gear width direction (shaft length)
Direction) Axial length direction between the two while keeping dimensions to the minimum necessary
To prevent misalignment and press-fit together
To avoid inconvenience on stress or strain like
It is to provide a gear set having features .

[0008]

According to the present invention, there is provided a gear set for transmitting power from a crankshaft to a camshaft, wherein the gear set is disposed in a four-stroke engine. A gear is arranged via a bearing, and the outer ring of the bearing and the boss of the gear have the same width and a circlip is fitted between fitting surfaces to be fitted. Is
A groove is formed on the outer peripheral surface of the bearing outer ring so that the entire circlip that has been elastically deformed can be immersed. Once formed on the peripheral surface, it is elastically deformed until it is completely immersed in the former groove, and the above-mentioned fitting is enabled.After the fitting is completed, it is restored to a natural state and partially immersed in the latter groove. to remain in position across each mating surface of the Te, to the arrangement of the circlip, and, two of the holder pre
Press and hold the collar (tube) on the
Attach the gear through the bearing described above, and
Mounting a washer between the holder plate and
It is characterized by the following.

In this gear set of the first aspect,
When the circlip is mounted in the width direction of the bearing or gear (shaft
The length of the shaft between the two while keeping the dimensions to the minimum necessary
To prevent displacement in the direction, and to connect the two by press-fitting.
Avoid stress or strain inconveniences such as Ma
Also, by doing this, the gear set can be made thin.
And place them properly in the engine, resulting in
The engine can be made compact.

[0010]

The washer to be mounted as described above is
In addition to the role of stopping the bearing from shifting in the axial direction on the collar, it also serves as a spacer for securing a clearance between the bearing and the gear and the holder plate. Therefore, in this gear set, the position of the gear does not shift in the axial direction on the outer periphery of the collar, and there is no disadvantage that the side surface of the gear contacts the holder plate.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 relate to the present invention .
Here is a reference embodiment . 1 (a) is fitted integrally
An example in which the bearing 10 and the gear 20 are mounted on the shaft 1 is shown. FIG. 2B shows a circlip (retaining ring) 30 mounted between the bearing 10 and the gear 20. FIG.
(a)-(c) is explanatory drawing which shows the procedure at the time of fitting the bearing 10 and the gear 20 with sectional drawing. These are
For ease of understanding, the example of FIG.
This is shown below.

In this embodiment, as shown in FIG. 1A, a gear 20 is mounted on a shaft 1 via a bearing 10 so as to be rotatable. With respect to the mounting of the gear 20 in this manner, there are the following conditions in design. That is, the dimensions and types of the gear 20 and the bearing 10 are
It is set in consideration of the relationship between strength and durability in consideration of the load acting on zero, the rotational speed, and the like, and restrictions on the space allowed near the gear 20, and the width of the outer ring 11 of the bearing 10 and the gear 20. The width (of the boss) matches as shown. It is necessary to fit the gear 20 so as not to come off the outer ring 11. However, it is impossible to provide a retaining means so as to protrude from the gear 20 in the thickness direction. Taking such a space is not recognized in terms of bearing life. However, the shaft 1 is long, and a portion near the outer peripheral surface including the front and rear of the inner ring 12 of the bearing 10 has a spatial margin (that is, no other interference is near).

Under the above conditions, in this embodiment, the bearing 10 and the gear 20 are mounted on the shaft 1 as follows.

First, the fitting of the bearing 10 to the shaft 1 employs a clearance fit including a gap of several hundred percent and is formed on the shaft 1 as shown in FIG. The position is determined by a shoulder 2 and a circlip (retaining ring) 4 mounted on the shaft 1. The shoulder 2 is formed by thickening a portion of the shaft 1 adjacent to the location where the bearing 10 is provided, and the circlip 4 is formed with a groove 3 in a portion adjacent to the bearing 10 on the side opposite to the shoulder 2 and having a high height. Approximately half of the size (radial dimension) is submerged. As described above, since there is room in space only around the shaft 1, the retaining means can be provided outside the bearing 10 as described above. The used circlip 4 is a known part which is commercially available and has a rectangular cross section that is long in the radial direction as shown in the figure, and the groove 3 has a depth in which a part of the circlip 4 is submerged. It has a rectangular cross section. That is, groove 3
Is relatively deep and has a 90 ° square corner, so that it is easy to concentrate stress in the vicinity of the shape.
Since no force is applied to the tip of the shaft 1 provided with the groove 20 by the gear 20 or other objects, no stress-related problem occurs with respect to the groove 3. Here, the fitting of the shaft 1 and the bearing 10 is described first, but as a general procedure for actually assembling, the bearing 10 and the gear 20 are first fitted, and the integral It is fitted on the shaft 1 later.

Second, the fitting of the gear 20 to the bearing 10 is an interference fit (press-fit) having an interference of several hundredths of a millimeter, but ensures that the gear 20 will not slip off in the axial direction. For this reason, the circlip 30 is mounted between the respective fitting surfaces 10a and 20a. Circlip 30
Fig. 1 (b) is a diagram in which a wire made of spring steel having a circular cross section as shown in Fig. 1 (b) is wound into a C shape in a round shape, and as shown in Fig. 1 (a), each of the fitting surfaces 10a and 20a , The gear 20 is prevented from moving on the bearing 10 in the axial direction. That is, the outer peripheral surface of the outer race 11 of the bearing 10 (that is, the engaging surface 10a) and the inner peripheral surface of the gear 20 (the inner peripheral surface ( That is, the grooves 13 and the grooves 21 are respectively formed on the fitting surfaces 20a), and the circlip 30 is disposed between the grooves 13 and 21 such that the center of the wire crosses the fitting surfaces 10a and 20a. Has been placed. Even if the bearing 10 and the gear 20 are slid between the fitting surfaces 10a and 20a and relatively move in the axial direction, the movement is prevented by the shear strength of the circlip 30. Since the circlip 30 does not protrude out of the bearing 10 and the gear 20 at all,
The above-described space constraint will be cleared in the most preferable manner.

In mounting the circlip 30 between the bearing 10 and the gear 20 as described above, specifically, the following means is employed. That is, as shown in FIG. 2A, as shown in FIG. 2A, a groove 13 is formed in a fitting surface 10a (that is, an outer peripheral surface) on the outer ring 11 of the bearing 10, and the fitting is performed in a natural state here. A circlip 30 of a size that exposes a face is fitted onto the mating surface 10a. The groove 13 is formed at a portion near one of the end faces, avoiding a central portion of the outer ring 11 where the load condition is strictest. When the elastic ring is deformed, the entire circlip 30 is formed therein. It can be submerged. The bottom of the groove 13 has a semicircular cross-section so that it does not have an extra depth along the outer shape of the circlip 30 and easily disperses stress.

As shown in FIG. 2B, the fitting surface 20 a of the gear 20 is put on the fitting surface 10 a of the bearing 10, and the two are fitted by moving the gear 20 in the direction of the arrow shown in the figure. Since the bearing 10 and the gear 20 are interference-fitted, the temperature of the gear 20 is raised during this operation. When the end of the gear 20 comes to the position of the circlip 30, the circlip 30 is elastically deformed with a tool or the like in a direction to reduce the diameter so as to be hidden inside the groove 13, and while the gear is being deformed in such a manner. Move 20 onto circlip 30. A tapered surface 20b continuous with the fitting surface 20a is formed at the end of the gear 20 so that the end of the gear 20 can get over the circlip 30 smoothly. While the gear 20 moves in the illustrated state and the fitting surfaces 10a and 20a slide, the circlip 30 in the groove 13 is pressed against the fitting surface 20a of the gear 20, so that the groove 1
It is kept submerged in 3. A groove 21 is formed on the mating surface 20a of the gear 20 so that when the bearing 10 and the gear 20 are fitted in a predetermined positional relationship, the groove 13 on the bearing 10 coincides with the groove 13 on the bearing 10 in the axial direction and the inside and outside. Has formed. The groove 21 has a semicircular cross section, and its depth is half the diameter of the strand of the circlip 30.

As the fitting operation proceeds as described above, the gear 20 eventually reaches a predetermined position on the bearing 10 and the gear 20
The groove 21 formed on the bearing 10 continues just outside the groove 13 on the bearing 10. The circlip 30 which has been immersed in the groove 13 due to elastic deformation spreads at this point until it hits the bottom of the groove 21, and as shown in FIG. And the fitting is completed.

In the state shown in FIG. 2C, the bearing 10 and the gear 2 can be mounted without damaging the circlip 30 and the like.
Although the circlip 30 cannot be separated again, the circlip 30 cannot be detached or the gear 20 can be accidentally removed from the bearing 10 without your knowledge. Bearing 1
Since the 0 and the gear 20 are small and are not particularly expensive, if any of them needs to be replaced, they may be replaced as a unit.

Next, FIG. 3 shows a specific embodiment in which the present invention is applied to an actual machine. FIG. 3 is a sectional view showing a drive mechanism of the intake / exhaust cam shaft 42 in the four-cycle engine 40.

In this embodiment, a gear set 50 in which three gears 57, 58, and 59 are integrated into one unit is arranged so that power is transmitted from the crank gear 41a on the crank shaft 41 to the cam gear 42a on the cam shaft 42. I have. The gear set 50 press-fits and holds three collars (cylinders) 51, 52, 53 in two holder plates 50a, and puts the gears 57, 58, 53 on the respective collars via bearings 54, 55, 56.
59 are attached, and they are meshed in series. In an embodiment, such a gear set 50
The gear 57 meshes with the crank gear 41a, the gear 59 meshes with the cam gear 42a, and the collars 51, 52, 53 are connected to the cylinder 44 or the cylinder head 4 by bolts 50b, 50c or stepped pins 50d.
3 so that it is arranged in the engine 40. Thus, the rotational force of the crankshaft 41 can be transmitted to the camshaft 42 via the three gears 57, 58, 59 in the gear set 50.

Each of the gears 57 and 58 of the gear set 50
It is necessary to prevent 59 from moving in the axial direction between the two plates 50a. Each color 51.5
When the position is shifted in the axial direction on the outer circumference of the gear 2 ・ 53, the gear 5
This is because power transmission becomes inefficient, for example, the side surfaces of the plates 7, 58, 59 contact the plate 50a. Therefore, an appropriate means for preventing the shift in the direction is necessary, but there is no room in the engine 40 as a space for accommodating the gear set 50, and it is also inconvenient to enlarge the external dimensions of the engine 40.

Therefore, in this embodiment, as shown in the partial detailed drawing (drawing portion), a washer 61 is mounted between the inner ring of the bearing 56 and the two plates 50a.
The outer ring of the bearing 56 and the boss portion of the gear 59 have the same width, and the circlip 60 is used between the fitting surfaces of the two, as shown in the embodiment (FIG. 1 and the like) (other bearings). The same was applied between the gears 54 and 55 and the gears 57 and 58). The washer 61 serves to prevent the bearing 56 from shifting in the axial direction on the collar 53, and also serves as a spacer for securing a clearance between the bearing 56 and the gear 59 and the plate 50a. In addition, the circlip 60 mounted as described above prevents the bearing 56 and the gear 59 from shifting in the axial direction between the two while keeping the width (axial direction) dimensions of the bearing 56 and the gear 59 to the minimum necessary. This avoids the disadvantages of stress or strain as in the case of joining at a time.
By doing so, the gear set 50 can be configured to be thin and appropriately arranged in the engine 40, and as a result, the engine 40 can be made compact.
Various benefits were obtained.

Although the reference embodiments and examples of the present invention have been described above, the present invention can be embodied as follows. For example, a) the cross-sectional shape of the retaining ring (circlip etc.) is not necessarily circular. Even if the shape is an ellipse or an oval, the effect of making the groove relatively shallow and avoiding concentration of stress in the vicinity thereof can be expected.

B) When it is necessary to transmit a strong torque between the fitting surfaces, such as when the gear is directly fitted to the shaft, a key (and a key groove) serving as a detent means is provided between the surfaces. It is good to use together.

C) The retaining ring can be mounted not only in the plane perpendicular to the axis as in the above-described embodiments and examples, but also in a plane obliquely intersecting the axis. In this case, the retaining ring can be used not only as a stopper but also as a stopper.

[0028]

The gear set according to the first aspect has the following effects. In other words, 1) The mounted circlip is in the width direction (shaft ) of the bearing or gear.
The length of the shaft between the two while keeping the dimensions to the minimum necessary
To prevent misalignment, and press-fit them
Avoids stress or strain inconveniences as may be the case.

2) It can be configured to be thin and properly arranged in the engine.
As a result, the engine can be made compact.

Further, 3) the position of the gear does not shift in the axial direction on the outer periphery of the collar due to the washer to be mounted, and the inconvenience of the side surface of the gear contacting the holder plate is avoided.

[Brief description of the drawings]

FIG. 1 is a reference embodiment related to the present invention,
FIG. 1A is a cross-sectional view showing an example in which a bearing 10 and a gear 20 fitted together are mounted on the shaft 1, and FIG. 1B is a stop attached between the bearing 10 and the gear 20. FIG. 3 is a perspective view of a wheel 30.

FIGS. 2 (a) to 2 (c) are explanatory views showing a procedure for fitting the bearing 10 and the gear 20 in the example of FIG. 1 (a) in a sectional view.

FIG. 3 is a cross-sectional view showing a drive mechanism of an intake / exhaust camshaft 42 in a four-cycle engine 40 as a specific embodiment using the present invention .

FIG. 4 is a cross-sectional view showing a conventional example in which a gear 20 'is fitted on a bearing 10' only by press-fitting.

[Explanation of symbols]

10.56 Bearing (member having outward fitting surface) 10a fitting surface 13 groove 20.59 Gear (member having inward fitting surface) 20a fitting surface 21 groove 30.60 circlip (retaining ring) ) 50 gear set

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-42718 (JP, A) Japanese Utility Model Showa 58-82517 (JP, U) Japanese Utility Model Showa 54-150994 (JP, U) Japanese Utility Model Showa 51- 46051 (JP, U) Fully open 50-61250 (JP, U) Fully open 55-122556 (JP, U) Fully open 4-111949 (JP, U) Fully open, 5-61457 (JP, U) Hikaru 3-103178 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16B 21/18

Claims (1)

(57) [Claims] 1. A gear set disposed in a four-stroke engine for transmitting power from a crankshaft to a camshaft, wherein a gear is disposed between two holder plates via a bearing, and an outer ring of the bearing is provided. And the boss of the gear shall be the same width, and a circlip shall be fitted between the mating surfaces and fitted. In order to mount the circlip, the entire elastically deformed circlip shall be submerged. A groove with a depth that can be obtained is formed on the outer peripheral surface of the bearing outer ring, and a groove with a depth that allows a part of the circlip to be restored to its natural state to be partially immersed is formed on the inner peripheral surface of the gear. Elastically deformed until the whole is submerged in the groove to enable the above-mentioned fitting, and after the completion of the fitting, restored toward the natural state, partially immersed in the latter groove and at a position crossing each of the above-mentioned mating surfaces Arrange circlips to stay This was location
And press-fit the collar into two holder plates
And mount the gear on the collar via the bearing described above.
Between the inner ring of the bearing and the two holder plates.
A gear set characterized by wearing a sha.