JPS62125118A - Ram for diesel pile hammer - Google Patents

Abstract

PURPOSE:To alleviate the stress of the curved surface secrion of a neck section by forming specific two radii of curvature to a continuous shape. CONSTITUTION:A horizontal plane section 21 to which a hook for starting is latched and a perpendicular section 23 as the outer surface of a minimum diameter section are formed continuously through a curved surface section 22. The curved surface section 33 is formed to a double curvature shape that a small curvature-raisddsection 22a and a large curvature-radius 22 continue successively. The opposite angle of the small curvature-radius section 22a takes 35 deg. or 80 deg.. Accordingly, the stress of the curved surface section 22 of a neck ection 2 is dispesed into two curvature-radius sections 22a, 22b, and the maximum stress value of the curved surface section 22 is reduced, thus lightening the fatidue of the neck section, 2 then lenghtening the lifetime of a ram.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a ram for a diesel pile hammer having an improved neck shape.

(Prior Art) FIG. 5 shows the general shape of the ram of a diesel pile hammer. To the ram, the neck 1 is placed on the upper side, and after the ram 8 is lifted to a predetermined height by the hook [3 (shown in Fig. 2)] which is attached to the neck 1 when the hammer is started, Free fall. Conventionally, as shown in FIG. 4, the neck 1 for this ram has two parts: a horizontal surface part 11 where the hook B is held, and a vertical surface part 1 which is the outer surface of the smallest diameter part of the neck part.
3 are continuously formed through the curved surface portion 12.

Incidentally, impact stress is generated throughout Ram 8 due to the impact of pile 4, and particularly high stress acts on section 11.

In this case, in the conventional neck portion 1 of the ram, the curved surface portion 12 is formed into a single curvature shape with a single radius of curvature no, so stress concentration occurs on this curved surface portion 12 as shown in FIG. This caused severe fatigue in the neck 1.
There is a problem that 1 tends to occur occasionally (the life of the entire ram becomes low).

Note that as a measure to alleviate stress, it is possible to increase the radius of curvature Ro of the curved surface portion 12, but other methods (horizontal surface portion 1
1 and the minimum diameter of the blind portion), it is difficult to obtain sufficient effects. In addition, as shown in Japanese Utility Model Publication No. 54-4242, there is a known means for forming a plurality of uneven surfaces on the upper end surface of the ram and reducing the impact stress by the diffuse reflection reduction Q effect of the four west surfaces. It has become. However, according to this, machining of the convex surface for opening the L gate is troublesome, and there is a risk that the convex portion R1 of the concave and convex surface may be chipped.

(Objective of the Invention) Therefore, the present invention provides a ram for a diesel pile hammer that is easy to process and is capable of effectively reducing the stress on the curved neck portion.

(Structure of the Invention) The feature of the present invention is that an activation hook is provided at the top of the I
I) A neck portion is provided, and this neck portion is formed by continuously forming a horizontal surface portion on which the rough hook 1F is placed and an Iπ face portion, which is the outer surface of the small diameter portion of the neck flu, through a curved surface portion. The curved surface part is formed into a double curvature shape in which two types of large and small curvature radius parts are continuous with the small curvature radius part on the upper side, and the diagonal of the small curvature radius part is set in the range of 350 to 800. There is a ram, which is a diesel pile hammer, which has been made. Next, I will explain this.

FIGS. 1 and 2 show an enlarged view of a part of the neck 2 of the ram J3 of the present invention. 21 is a water W surface portion where the hook B is held (II); 23 is a small surface portion which is the outer surface of the minimum diameter portion of the i portion; the horizontal surface portion 21 and the vertical surface portion 23 are continuously formed via the curved surface portion 22 There is. This curved surface portion 22 has an upper portion 22a continuous to the horizontal surface portion 21 having a small radius of curvature 1 te, and a lower portion 22a continuous to the center of gravity surface ~S23.
2b is formed into a double curvature shape with a large radius of curvature R2. Hereinafter, the upper part 22a will be referred to as a small radius of curvature part.
The lower portion 22b is referred to as a large radius of curvature portion. in this way,
By making the curved surface portion 22 have a double curvature shape, the basic effect is that the stress acting on the curved surface portion 22 is dispersed into two curvature radius portions as shown in FIG. 1, and the maximum stress of the curved surface portion 22 is The value can be lowered.

In Fig. 2, 11'11 water 11 length of surface part 21, 1
1 is necessary to form the curved surface portion 22 <'K (curved surface portion 2
2) Horizontal quality, Do is the maximum diameter of the ram, D is i''
The minimum diameter of part i is shown. Behind this, horizontal surface part quality H
' is set within a certain range of 31 as a dimension that can be reliably hooked with the hook B/). Generally speaking, It' = 0.01 to 0. ID.

is set to

In addition, the minimum diameter of the neck [] is set within a certain range of dimensions for strength reasons. Accordingly, the horizontal length 11 dimension of the curved surface portion 220 is determined (given) by these dimensions. V3. Inside the body, l''-0,01''・0.1 D.

The size range is set to .

Then, the small curvature half 1\R1, the large lll bi;゛・4 radius R2, the diagonal of the small curvature radius portion 22a (the square turtle occupying the curved surface portion rest) 01, and the ten curved surface portions Relational expression of g1%
Formula %) ...Formula (1) Shout. In addition, in FIG. 2, 02 is the large radius of curvature portion 22b.
There is a diagonal of
Once these two are determined, the other 10 (as it is determined from the above equation (1)), fix the curved surface length 11 to a dimension that is naturally determined in practice, and freely combine any two variables V. , stress concentration coefficient αR1 of both radius portions 22a and 22b
, αR2 of 1.11 and comparing them, it is possible to determine a preferable double curvature shape of the curved surface portion 22.

(Example) Curved surface part ■; Small radius of curvature R1 at H = 20 M
In the case of 5 types of 5M, 7M, 8M, 101M112mm, stress concentration coefficient αR1゜α17 by i1 finite element method
2 analysis was conducted. The results of this analysis are shown in Figure 3. 1
As can be seen from Figure 11, when θ1=600, α171
R2 becomes approximately the same value, and it is clear that at this 01 angle, the stress is doubled equally on both curvature parts 22a and 22b (,1). Therefore, this 01-
By determining the dimension values of [+ and R2 with 600 as the optimum condition for the double curvature shape, the maximum stress value of the curved surface portion 22 can be suppressed to the minimum. Note that the small radius of curvature R1
t, the shape of the curved tip of the hook B, etc. are taken into consideration in determining the value.

Also, the large curvature half 1\R2 is calculated from the above formula (1), R2=
(II-R+ sin θ1) / (1-sin θ1)
is given by

Based on the optimal double curvature shape obtained in this manner, we determined the range in which the stress reduction effect can be effectively utilized in terms of the life of the ram, and experimentally found that the numerical range of θ1 = 350 to 800 is an appropriate range. Recognized as II. For example, H=
20M, R1=5m, θ1-(33042', R2
= 150s+, the stress concentration rate of the curved surface portion 22 is 1
．． 506, and the conventional single radius of curvature Ro = 20s
Stress concentration rate 2 in case of curved surface part 1 with (l-1 = 20 mm>
．． 463, a stress reduction rate of 61.1% was obtained.

(Effects of the Invention) According to the present invention, the stress of the curved surface in the neck can be dispersed into two radii of curvature, and the maximum stress value of the curved surface can be reduced. Portrait;
1) It can reduce fatigue and improve the life of a ram. 4) It has a hit configuration of shim and double curvature shape, and is easy to process.

[Brief explanation of drawings]

Figure 1 is an enlarged front view of a part of the neck that connects JH to the clear ram with a wooden block, Figure 2 is a diagram to explain the 1-way relationship of each part of the neck, and Figure 3 is a small curvature half-section. The angle θ1 occupied by the 1 yen portion
FIG. 4 is a diagram corresponding to FIG. 1 showing the neck shape of a conventional ram, and FIG. 5 is a front view showing the general shape of the ram. 2... Neck part, 21... Horizontal surface part, 22... Curved surface part, 22a... Small radius of curvature part, θ1... Diagonal of the same part, 22b... Large radius of curvature part, 23... ...irI facing part.

Claims (1)

[Claims] 1. A neck section is provided at the top where a starting hook can be hung,
This neck part is formed by continuously forming a horizontal part on which the hook is hung and a vertical part which is the outer surface of the smallest diameter part of the neck part through a curved part, and this curved part has two types of curvature radius parts, large and small. is formed into a continuous double curvature shape with the small radius of curvature part on the upper side, and the diagonal of the small radius of curvature part is 3.
A ram of a diesel pile hammer characterized by being set in a range of 5° to 80°.