JP2527815Y2 - Tapet with polymerized shim - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tappet used for a direct-acting type valve operating mechanism, and more particularly to a tappet provided with a polymerization shim in which at least two upper and lower shims for adjusting a valve clearance are stacked .

[0002]

2. Description of the Related Art FIG. 2 schematically shows a direct-acting type valve operating mechanism frequently used in a DOHC type engine. An engine valve (01) includes a pair of cutters (02) (02) and a spring. Attached to the cylinder head (05) by a retainer (03), a valve spring (04) and the like.

[0003] At the upper portion of the engine valve (01), the upper surface tappet (06) provided in the Tapetsuto body cylindrical which is closed (06a), the lower surface is an engine valve of the upper wall (07) and forming a circular ( the stem end of the 01) in the so that to contact, is fitted from above.

[0004] upper wall (07) upper surface is provided et the annular side wall of the (0
The inner side of 8), a circular recess (09) is formed, the recess (0
9) is fitted with a shim (010) for adjusting the valve clearance.

The engine valve (01) has a cylinder head (0)
5) whole tappet (06) which is guided in the, by the push down al with shims (010 rotating cam is brought into contact with the upper surface of) (011), it is opened and closed.

[0006]

In order to adjust the valve clearance in such a direct acting type valve operating mechanism,
Prepare multiple types of shims (010) with different thicknesses, and select and install the shim (010) with the required thickness according to the interval between each tappet (06) and the rotating cam (011). I am trying to do it.

[0007] In this case, the valve clearance, for example, since it is necessary to adjust the accuracy like 0.02 to 0.05 mm, Contact prepared many kinds of shims that different thickness (010)
I have to work .

That is, the tappet (06) and the rotating cam (011)
Is assumed to be "T" and the unit amount of adjustment of the valve clearance to be "t", the required number "N" of types of shims (010) is as follows . N = T / t + 1

For example, the amount "T" at which the interval changes is 1.6 m.
If the adjustment unit amount “t” is 0.05 mm in the case of m,
The number of types “N” of the thickness of the shim (010) is 33 types. "T" to adjust valve clearance with higher accuracy
Is 0.02 mm, there are 81 types of "N".

[0010] Preparing such a variety of shims (010) makes inventory management complicated, increases dead stock, is uneconomical, and requires an individual tapet (06).
In each case, it is necessary to select a shim (010) having an appropriate thickness from various types according to the distance from the rotating cam (011), which is not preferable in terms of work management .

The present invention overcomes these disadvantages and requires less valve clearance with fewer types of shims.
It is an object of the present invention to provide a tappet that can be adjusted to the accuracy of the tappet.

[0012]

In order to achieve the above object, the tappet of the present invention has a cylindrical shape whose upper surface is closed.
In the recess formed at the upper end of the tappet body,
Shim is overlapped up and down to fit, and the lowest shim
Shall not be able to rotate around the axis with respect to the tappet body.
The next higher shim can rotate around the axis with respect to the lower shim
It is characterized by having.

For this purpose, the lower surface of the lowermost shim is roughened.
Or the lower surface of the bottom shim and the tape
A protrusion is formed on one of the concave surfaces of the
On the other hand, it is necessary to form a concave groove with which the projection can engage.
Not good.

If the thickness of each shim is made different, the
Is even larger.

[0015]

According to the total thickness of at least two shims,
Since the valve clearance can be adjusted, the types of shim thickness can be greatly reduced as compared with the case where the valve clearance is adjusted by a single shim, and the inventory management of the shim is facilitated.

The lowest of the shim is not rotate with respect to the tappet body, and the upper shim against the underside of the shim,
Because it is rotatable, wear of the tappet body is reduced, the tappet body, even if the subject to wear aluminum light alloy or the like <br/>, may be used without inconvenience.

[0017]

1 is a sectional view showing an embodiment of the present invention.
The structure is almost the same as that of the conventional valve train shown in FIG. That is, an engine valve (1), a pair of cotters (2)
(2), spring retainer (3), valve spring
(4) The cylinder head (5) and the upper rotating cam (10)
This is the same as the conventional example of FIG.

The tappet (6) is also similar to the conventional example shown in FIG.
It has a cylindrical tappet body (6a) with a closed upper surface, and a circular recess () is formed inside an annular side wall (8) connected to the upper part of a circular upper wall (7). 9) is formed.

Each of the recesses (9) has a first disc-like shape.
The second shim (11) and the second shim (12) are overlapped and fitted. Hereinafter, the lower first shim (11) is referred to as “lower shim”,
The upper second shim (12) is referred to as the "upper shim."

The lower surface of the lower shim (11) is formed to be rough, so that a large abrasion resistance is generated between the lower surface of the tappet (6) and the upper wall (7). Top and upper shims (12)
Is formed smoothly so that the upper and lower shims (11) and (12) are relatively slidably rotated on the surfaces where they contact .

[0021] Alternatively, one the protrusion of the lower surface of the lower shim to the top wall of the tappet (6) (7) (11), likewise on the other, to form a groove in which the protrusion is fitted, the lower Sim (11) Tape
It may be fitted to the slot (6) so that it cannot rotate reliably .

As the lower shim (11) and the upper shim (12), a plurality of types having different thicknesses in the axial direction are prepared. However, in one shim, the thickness is changed in accordance with a dimension obtained by dividing a required adjustment range of the valve clearance by a relatively coarse pitch (hereinafter, referred to as a first pitch), and The thickness is changed in accordance with the size obtained by subdividing one pitch by a second pitch corresponding to a desired adjustment unit amount.

The lower group of lower shims having these thicknesses changed
(11) and one of the upper shims (12) according to the distance between the individual tappet (6) and the rotating cam (10), and each one is selected and mounted, so that the thickness is the first. The valve clearance can be adjusted as required by performing a coarse adjustment using a shim that varies with the pitch and a fine adjustment using a shim that varies with the second pitch. In this case, the first pitch is the amount of the range in which the interval between the tappet (6) and the rotating cam (10) changes,
It is desirable that the values be equally divided by integer values.

Hereinafter, specific numerical values will be described.
In this case, the thickness (T ₁ ) of the lower shim (11) is changed at a first pitch, and the thickness (T ₂ ) of the upper shim (12) is changed at a second pitch.

In order to facilitate comparison with the conventional example in which the thickness of the single shim is changed, the tappet (6)
The amount "T" at which the distance between the rotating cam (10) and the rotating cam (10) changes is 1.6 mm,
The case where the adjustment unit amount “t” of the valve clearance is 0.05 mm will be described.

Assuming that the first pitch at which the thickness of the lower shim (11) changes is 0.4 mm obtained by dividing the interval change "T" into four equal parts,
As the lower shim (11) and the upper shim (12), those having the following thicknesses may be prepared.

The thickness (T ₁ ) of the lower shim (11) for coarse adjustment
At a pitch of 0.4 mm, the lower shim (11)
There are the following five types. _{(11 1) T 1 = Ta} (11 2) T 1 = Ta + 0.4mm (11 3) T 1 = Ta + 0.8mm (11 4) T 1 = Ta + 1.2mm (11 5) T 1 = Ta + 1.6mm where , Ta are reference thicknesses of the lower shim (11).

Thickness (T ₂ ) of upper shim (12) for fine adjustment
Is changed at a pitch of 0.05 mm, the upper shim (12)
Are the following eight types. _{(12 1) T 2 = Tb} (12 2) T 2 = Tb + 0.05mm (12 3) T 2 = Tb + 0.1 mm (12 4) T 2 = Tb + 0.15mm (12 5) T 2 = Tb + 0.2 mm (12 ₆ ) T ₂ = Tb + 0.25 mm (12 ₇ ) T ₂ = Tb + 0.3 mm (12 ₈ ) T ₂ = Tb + 0.35 mm where Tb is the reference thickness of the upper shim (12).

By selecting and mounting one of each of the five types of lower shims (11) and eight types of upper shims (12), a tappet ( The valve clearance can be adjusted to a predetermined amount according to the distance between 6) and the rotating cam (10).

When the tappet (6) and the rotary cam (10) are arranged closest to each other, that is, when the amount of change "T" in the distance between the tappet (6) and the rotary cam (10) is 0 mm, the thickness is below the reference thickness (Ta). Side shim (1
By selecting and mounting 1) and the upper shim (12) having the reference thickness (Tb), the valve clearance can be adjusted to a predetermined amount.

Here, when the distance between the tappet (6) and the rotary cam (10) is increased and the amount of change in the distance "T" is increased to 0.85 mm, the lower shim (11) is used as the lower shim (11). ₁ = Ta + 0.8 mm
(11 ₃ ) is selected, and T ₂ = Tb + 0.3 is set as the upper shim (12).
If a (12 ₂ ) of 05 mm is selected and installed, the added value of the increase in thickness of the two shims will be 0.85 mm, which corresponds to the increase of “T”, and the valve clearance will be the same as above. It can be adjusted to quantitative.

[0032] When the distance change amount "T" is increased to a maximum of 1.6mm as the lower shims _{(11), T 1 = Ta} + 1.6mm
Select of (11 _5), as an upper shim (12), T ₂ = Tb (12
₁ ) can be selected.

By selecting and combining one of the five types of lower shim (11) and eight types of upper shim (12), the interval change amount “T” is 0 mm to 1.6 mm. When changing in the range, the valve clearance is 0.05mm
The unit can be adjusted.

In the case of adjusting with a single shim (010) shown in FIG. 2, it is necessary to prepare 33 kinds of shims whose thicknesses are changed at a pitch of 0.05 mm, but they are superimposed. In the case of FIG. 1 in which the lower shim (11) and the upper shim (12) are adjusted in two places, it is sufficient to prepare 13 types of shims in total, which greatly reduces the number of types of parts. Can be done.

When the valve clearance is more finely adjusted, the rate of reduction in the number of types of parts is further increased. For example, when adjusting the valve clearance at a pitch of 0.02 mm, in order to adjust with a single shim (010), it is necessary to prepare 81 types of shims as described above. As the side shim (11), there are five types with the same thickness changed at the 0.4 mm pitch as described above, and as the upper shim (12), twenty types with the thickness changed at the 0.02 mm pitch, for a total of 25 types You just need to prepare.

In the above embodiment, the thickness of the lower shim (11)
(T ₁ ) is changed at a relatively coarse first pitch, and the upper shim is changed.
Although the thickness (T ₂ ) of (12) is changed at a second pitch obtained by subdividing the first pitch, the upper shim (12) is changed at the first pitch and the lower shim (11) is changed at the first pitch. ) May be changed by the second pitch. However, when adjusting the valve clearance in actual work, usually, a coarse adjustment for selecting a shim that changes at the first pitch is performed first, and then a shim that changes at the second pitch is selected and finely adjusted. Because of the adjustment, the upper shim is easier to replace due to the construction of the tappet (6).
It is practically advantageous to change the thickness (T ₂ ) of (12) at the second pitch.

The lower shim (11) and the upper shim (12), which are vertically overlapped, are not necessarily made of the same material. That is, as the upper shim (12) on which the rotating cam (10) slides, it is necessary to use a hard material such as high-speed steel or tool steel in order to prevent wear, but the lower shim (11) Since less expensive materials may be used, material costs can be reduced.

[0038]

(A) Since the valve clearance can be adjusted by the total thickness of at least two shims, the thickness of the shim can be adjusted as compared with the case where the valve clearance is adjusted by a single shim. Can be greatly reduced. Therefore, the types of shims to be prepared are reduced, and inventory management becomes easy.

(B) Since only a few types of shims are required, dead stock is reduced and the system is economical.

(C) Of the two upper and lower shims, the lower shim that does not contact the rotating cam can be made of an inexpensive material, so that the cost can be reduced.

(D) The configuration of the tappet body and the peripheral members can be implemented without major changes.

[0042] (e) the lower shim is non-rotatable relative to the tappet body, and the upper shim, with respect to the lower shim,
Because it is rotatable, wear of the tappet body is reduced, the tappet body, Ri preferably der when wear easily aluminum light alloy or the like, also local wear of the upper shim
Is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the tappet of the present invention.

FIG. 2 is a cross-sectional view showing a conventional tappet having a single shim.

[Explanation of symbols]

 (1) Engine valve (2) Cotta (3) Spring retainer (4) Valve spring (5) Cylinder head (6) Tappet (6a) Tappet body (7) Upper wall (8) Side wall (9) Recess (10) Rotating cam (11) Lower shim (12) Upper shim

Claims (4)

(57) [Scope of request for utility model registration] 1. A plurality of shims are vertically arranged in a recess formed in an upper end portion of a cylindrical tappet body having a closed upper surface.
The lowermost shim is a tappet
It is impossible to rotate around the axis with respect to the main body, and the upper shim
Is a tappet provided with a polymerized shim, which is rotatable around an axis with respect to a lower shim . (2) The lower surface of the lowermost shim is formed with a rough surface.
A tappet comprising the polymerized shim according to claim 1. 3. The lower surface of the lowermost shim and the lower surface of the tappet body.
A projection is formed on one of the surfaces of the recess, and
And a concave groove with which the projection can engage.
A tappet provided with the polymerization shim according to 1. 4. The method according to claim 1, wherein each shim has a different thickness.
A tappet provided with the polymerization shim according to any one of claims 1 to 3.