JPH03334A - Laminated leaf spring - Google Patents

Abstract

PURPOSE:To obtain a rigid laminated leaf spring with soft driving comfortableness and high stability by eliminating a relative slide between the contacted points of a top plate with an adjacent under plate under load and setting the displacement caused by elastic deformation of the contacted part of the top plate within a specified range in equivalent displacement converted to the vertical displacement of the pivot at the center of the top plate. CONSTITUTION:This laminated leaf spring is composed of tapered leaf springs in which a top plate 1 and under plates 3 are tapered, and a contact point A of the top plate 1 with the under plate 3 of second leaf is positioned under the spring eye of the top plate 1. Also, the top plate 1, constituting the laminated leaf spring, is so constructed that is rigidity and the diameter of the spring eye meets a specified formula. Namely, the laminated leaf spring is composed of the top plate 1 with the spring eyes on both ends and the under plates, the contact points between the top plate and the under plate adjacent to the top plate are not slid relatively even when a load is applied, and the displacement caused by elastic deformation of the contacted part of the top plate is set within 0.010m to 0.015m in equivalent displacement converted to the vertical dispalcement of the pivot at the center of the top plate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stacked leaf spring constructed by stacking a parent plate and one or more daughter plates.

[Conventional technology]

In general, for stacked leaf springs, as shown in Figure 1,
A Taber leaf spring is known which is constructed by stacking a main plate 1 having a Berlin-shaped eye, that is, a Berlin-shaped eye 2, and a plurality of daughter plates 3.

Further, as a truck suspension, a stacked leaf spring in which a main plate 8 has an amplifier turn door eye 9, as shown in FIG. 2, is well known. The spring constant, which is the load-deflection characteristic of this upturned eye-shaped stacked leaf spring, is the 10th
It has the characteristics shown in the figure. That is, FIG. 10 shows a characteristic diagram of hysteresis that occurs in the friction between the plates of the stacked leaf spring when the stacked leaf spring is bent up and down. In this characteristic diagram, when the deflection X increases from point a in the standard load state, the load W increases. In addition, if the deflection
-h (-h Draw another characteristic diagram with d.Furthermore, if the deflection X is reduced to point e and then increased again, 6-e f-
Draw a characteristic diagram of Ill) and form a loop. In this loop, b-40Se→f is generally referred to as a transition portion. The slope of this transition section has a different amplitude or deflection
Even when calculated in terms of values, the shapes are almost the same, and as shown in FIG. 10, for example, b+ -C1% el-fl and bt-*C.

, C2-f2.

Also, for example, in Japanese Utility Model Application Publication No. 55-127141,
A stacked leaf spring is disclosed in which a steel roll is provided between each spring plate in the stacked leaf spring. Or, JP-A-56-1
Japanese Patent No. 41433 discloses a stacked leaf spring device in which the spring constant changes discontinuously at a predetermined load value.

[Problem to be solved by the invention]

By the way, in a stacked leaf spring that draws a characteristic diagram as described above, the performance of the stacked leaf spring is usually b-6, b, -h.
6. , b, -xe, (diagonal spring constants tK, tK1, tKt (represents a value almost close to the dynamic spring constant) obtained from the rotation and deflection of the load from the base point a % d
This is determined approximately by the width of the friction, that is, the characteristics determined by each amplitude.

Therefore, based on the load-deflection characteristics of an amplifier turned eye type stacked leaf spring as shown in Fig. 10, the diagonal spring constant, so-called dynamic spring constant, and the amplitude dependence of friction are determined as shown in Fig. 11. and as shown by the solid line in FIG. That is, it can be seen that in the range of small amplitude, the diagonal spring constant increases, and as the amplitude increases, the diagonal spring constant decreases and approaches the static spring constant.

However, for vehicle suspensions, it is desirable to have a spring with a small amplitude and a low spring constant, which provides a soft ride, and a spring with a large amplitude and a high spring constant, which provides a sense of rigidity with poor stability. Therefore, conventional laminated leaf springs have characteristics that are completely opposite to ideal characteristics, and can be said to be disadvantageous in terms of performance.

In this type of laminated leaf spring, in order to obtain a soft ride, in order to keep the diagonal spring constant low at small amplitudes, the number of springs constituting the laminated leaf spring may be reduced.
Alternatively, friction has also been reduced by inserting a low-friction material with a low coefficient of friction into the end of the plate, but if a stacked plate spring is configured in this way, the result will be as shown by the dotted lines in Figs. 11 and 12. Become. That is, the friction at large amplitudes is reduced and the diagonal spring constant is reduced, resulting in a suspension that lacks a sense of rigidity and has poor stability.

In addition, since this method only reduces the friction between the plates of the stacked leaf spring, the diagonal spring constant of the minimum amplitude (i.e., the spring constant that is approximately equal to the slope of the transition part at the minimum amplitude) is also sufficiently reduced. The problem is that it cannot be done.

The purpose of this invention is to solve the above problems,
A stacked leaf spring consisting of a main plate with an eye and one or more child plates is formed to have ideal spring characteristics, and the contact point between the main plate and the child plate, that is, the contact area. By configuring the structure so that the amount of displacement in the deformation limit range of elastic deformation of the spring plate from the elastic deformation of the parent plate and child plate until the first sliding starts is within a predetermined range, the small amplitude of the stacked leaf spring can be reduced. The diagonal spring constant and friction are suppressed to ensure a soft ride, while the diagonal spring constant and friction at large amplitudes are kept as large as before to provide a stable and rigid feel. To provide leaf springs.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention consists of a parent plate and a daughter plate that have eyelets at both ends, and the contact point between the parent plate and the daughter plate adjacent to the parent plate can be moved under a load without causing relative slippage. A structure in which the amount of displacement in which the contact portion of the parent plate is elastically deformed is converted into the amount of vertical displacement of the fulcrum of the central portion of the parent plate, and the converted displacement amount is within the range of 0.010 m - 0,015 m. The present invention relates to a stacked leaf spring having the following features.

Further, in this stacked leaf spring, the conversion f of the parent plate is
2. The overlapping spring according to claim 1, wherein the amount of il corresponds to the following formula.

However, P: Contact force between the main plate and child plate when applying design building Y$ and weight W to the entire spring plate, μ: Coefficient of friction between the spring plates, L: Between the U bolt of the main plate and the contact point The distance between the TAU bolt tightening is the distance between the main plate and the child plate at the part, R: the radius of the outer diameter of the center plate of the main plate, R゛: between the center of the plate thickness of the main plate and the contact point distance, KW; rigidity of the main plate (T/θ (where θ is the rotation angle of the eye when torque T is applied to the eye of the main plate)].

[Effect]

The stacked leaf spring according to the present invention is constructed as described above and operates as follows. That is, this stacked leaf spring is
Consisting of a parent plate and a child plate having eyes at both ends, the contact point between the parent plate and the child plate adjacent to the parent plate does not relatively slip under load, and the contact portion of the a plate elastically deforms. The amount of deformation is converted into the amount of vertical displacement of the fulcrum of the central portion of the parent plate, and the converted amount of displacement is 0.010 m = 0.015
Since it has a structure that is set so that it exists within the range of In addition, the diagonal spring constant and friction at large amplitudes with large span changes can be configured to be large enough to obtain characteristics that are dominated by normal plate-to-plate sliding friction, as in the past. can.

〔Example〕

Hereinafter, one embodiment of a stacked leaf spring according to the present invention will be described with reference to the drawings.

FIG. 1 shows a stacked leaf spring as an embodiment of the present invention. This stacked leaf spring consists of a main plate 1, which is the leafiest part, with Berlin-shaped eyeballs 2 on both ends, and a plurality of leaf springs (2 in the figure).
(2) daughter plates 3 are stacked over the entire length of the plates and fixed to each other by a center port 4 at the center of the plates. Further, the stacked leaf spring itself is fixed to the axle of the vehicle by a pair of U-bolts 10 arranged at a predetermined position, that is, at a position that serves as a fulcrum supporting the load of the central portion. This stacked leaf spring is composed of a tapered leaf spring in which a parent plate 1 and a daughter plate 3 are formed into a tapered shape. In addition, in the figure, 5 indicates a clip.

Regarding the stacked leaf spring according to the present invention, for example, as shown in FIGS. It is located in Further, the main plate 1 constituting this stacked leaf spring has a structure in which its rigidity Kw and eye diameter R satisfy the following formula.

That is, this stacked leaf spring consists of a parent plate and a daughter plate that have eyes at both ends, and the contact point between the parent plate and the daughter plate adjacent to the parent plate causes relative slippage under load. The amount of deformation at which the contact portion of the parent plate is elastically deformed without
The structure is such that the amount of vertical displacement of the fulcrum of the central portion of the parent plate is within the range of 0.010 m to 0.015 m. Specifically, the converted displacement amount satisfies the following formula.

Kw　　　　　　　　T However, all units are based on the Sl unit system.

P is the contact force between the main plate 1 and the daughter plate 3 when the design standard load W is applied to the entire spring plate, and as shown in Figure 1, in the case of a stacked leaf spring consisting of three spring plates. Generally, P=W/6.

μ: Coefficient of friction between steel materials, that is, between spring plates, L: Distance between the contact point A with the daughter plate 3 on the main plate 1 and the U port 10, which is the fulcrum of the central part, T, of the U bolt 10 Tightening is determined by the distance between the main plate 1 and the child plate 3 (see Fig. 4), R: the radius of the outer diameter of the eyeball 2 (see Fig. 3), R': the main plate 1
The distance between the thickness center of the board and the contact point A (if the main board I is the Berlin-shaped eye 2, R = R', and if the main board 8 is the up-turn eye 9, R >R'=O), Kw; If the rotation angle of the eyeball 2 when a torque T is applied to the eyeball portion due to the rigidity of the main plate 1 is θ, then the value is expressed as Kw=T/θ.

Here, to explain the rigidity Kw of the main board 1, in the above embodiment, the main board 1 and the child board 3 were constructed of taber leaves, but if the main board was constructed with the same thickness over the entire length, the rigidity Kw Kw is expressed by the following formula. This will be explained with reference to FIG.

In the following equation, the moment of inertia of area acting on the main plate 1 is I, the elastic modulus is E, and the radius of curvature of the curved connection part 7 between the eye 2 of the main plate 1 and the flat spring plate part 6 is r.

First, the main board 1 from the contact point A between the main board 1 and the daughter board 3 to the point C at the straight end of the main board 1 is made of a rigid body, and the end of the spring plate 6 of the main board 1 is made of a rigid body. If the main plate l from point C to the point where Upol) 10 is located is made of an elastic body, the angle change at point C will be μPRL/2E[, and the center point of the main plate 1 will be μPRL/ 2E (rotate.

In addition, from the contact point A to the boundary point B between the centerpiece 2 of the main plate l and the curved connection part 7, and from the point C to the dot, are made of rigid bodies,
Also, if the area from point B to point C is made of an elastic body,
The angle change at point B with respect to point C is as follows.

Furthermore, if the area from point B to point C is made up of a rigid body, and the area from point A to point B is made up of an elastic body, the angle change at point A with respect to point B is as follows.

Here, since the shape of the spring plate in a general stacked leaf spring is L > R > r, the angle change of the center part of the main plate l is dominated by rigidity from point C to the point Since the stiffness from A to point B and the stiffness from point B to point C can be ignored, it becomes μPRL/2EI.

Therefore, μPRL/2EI L The spring constant of the main plate 1 is KI = 6EI/L, so Kw
= KI L' / 3 L = becomes L Mushroom / 3, which is proportional to the windup stiffness of the parent Fit.

Therefore, in the following description, for convenience, Kw will be referred to as the wind-up rigidity of the main plate 1, that is, the rigidity of the main plate 1.

A stacked leaf spring according to an embodiment of the present invention has the above-mentioned configuration and operates as follows. The action of this stacked leaf spring will be explained with reference to FIGS. 1, 3, and 7. When the load that is applied when the vehicle is used in a constant load condition, that is, the design standard load W, is applied to the stacked leaf spring, two points are applied to the center point of the main plate L, that is, the contact point A between the main plate 1 and the child plate 3. A force P is applied from the child plates 3 after the number. Due to the frictional force μP generated by this force P, the torque μP−
R' is applied to the main plate 1, that is, a wind-up torque is applied to the main plate 1, and the main plate 1 winds up. That is, when the stacked leaf spring is under load, the contact area A between the parent plates vi and l and the daughter plate 3 does not relatively slip, and the parent plate 1
Rotation occurs within a deformation range in which the contact area A with the child plate 3 is elastically deformed. At this time, if the windup rigidity + stiffness of the main plate 1 is Kw, the rotation angle of the eye portion of the main plate 1, that is, the contact area A with the daughter plate 3 is μP-R/Kw.

In this state, the design standard load W is increased by ΔW, and the spring displacement (corresponding to the amount of vertical displacement), that is, the deflection X, is increased by 15 mm (0,0
15m) increase.

In this case, since W > ΔW, the change in P is considered to be small. At this time, the relationship between the design standard load W and the spring displacement X is as shown in Fig. 7, from point E to point F (E-F).
Until.

Next, the load Wt is reduced. In this case, in conventional stacked leaf springs, the displacement of the spring immediately causes slippage between the spring plates and frictional force acts, so the transition parts b-*c and e-=f are shown in Fig. 10. However, if a stacked leaf spring is configured as in the embodiment of the present invention, the wind-up of the main plate 1, which is the leafiest part, will prevent the center plate from slipping between the spring plates. Only when the part rotates and the torque stored by this rotation becomes greater than the frictional force does it begin to slip. Therefore, as shown in Figure 7, from point F to point G (FG) changes gradually, and begins to slide from point G and reaches point H, so as shown in the figure, a smooth hysteresis curve is drawn. It becomes like this.

The rotation angle (μP - R'/KW) of the eyepiece part of the main plate 1 caused by the wind-up of the main plate 1 is the displacement amount of the arc of the contact area A of the main plate 1 with the daughter plate 3 corresponding to the rotation angle. , that is,
When converted into the amount of displacement caused by elastic deformation of the parent plate l, it is as follows. In this case, if you take into account the reverse windup that occurs on the main board 1 and double it, you get (hereinafter referred to as this page margin) W.

Furthermore, with reference to FIG.
The converted amount of displacement converted into the amount of vertical displacement in the area corresponding to Porto 10 is as follows.

Kw　　　　　　　　　　　T becomes.

Specifically, as shown in FIG. 6, the displacement amount of the eyepiece part of the main plate I, that is, the contact area A of the main plate 1 with the daughter plate 3 is X, and the spring plate is bent in accordance with the displacement amount X. Each angle, that is, the angle formed by the contact area A between the main plate 1 and the child plate 3 when the main plate 1 and the child plate 3 are under no load is ψ, and the angle formed by the contact area A between the main plate 1 and the child plate 3 is the parent plate when the parent plate 1 and the child plate 3 are under a load. 1
The angle formed by the contact area A between the child plate 3 and the child plate 3 is ψ2, and the parent plate 1
Corresponds to the displacement position X of the arc of the contact area A of the main plate 1 with the child plate 3 (the amount of displacement due to elastic deformation of the main plate 1), which corresponds to the rotation angle of the eyepiece part of the main plate 1 caused by the wind door 7b. angle,
In other words, when the main plate 1 and the child plate 3 exceed the range of elastic deformation and slippage occurs between the main plate 1 and the child device 3 for the first time,
The angle corresponding to the displacement X between the main plate l and the child plate 3 is ψ,
Then, ψ1″=-ψ2′9 ψ3, and since ψ1 # ψ2# ψ, #T/L, the arc displacement IiX of the contact area A of the main plate 1 with the daughter plate 3 can be expressed as The converted displacement amount converted into a displacement amount is;

Therefore, the amount of displacement within the range of elastic deformation at the contact point A of tentative 1 with the daughter plate 3, in other words, the amount of displacement of the parent plate l where the contact point A of the parent plate l with the daughter plate 3 begins to slide for the first time. If the converted displacement amount of the spring is set to 0.015 m, that is, 15 mm as in the embodiment according to the present invention, first, the load on the spring plate is increased from the design standard load W, and the The fulcrum that receives the load W in the central part (U bolt 1
0)), the vertical displacement amount is 15 mm.
After deflecting by 15m, the above neutral point
When the winding is returned to m, the main plate 1 starts winding up and further reverse winding up. And the spring plate is 15mm
When the spring is returned to this point, the force accumulated by the reverse windup becomes equal to the frictional force μP, and slipping occurs between the spring plates from this point. Therefore, the friction at the neutral point of the spring plate is equal to that of a conventional ° spring. On the other hand, if the deflection of the spring plate is, for example, 10 mm, at the neutral point, the sliding at the contact area A of the main plate 1 with the daughter plate 3 has not yet occurred, so the friction at this time is greater than that of the conventional spring plate. It's small. The diagonal spring constant and the amplitude dependence of friction are determined from the results obtained using the above method, as shown in FIGS. 8 and 9.

That is, for example, due to roll when the vehicle is cornering, or when driving on a rough road, the spring plate may be affected by 15 m.
If an input of m or more occurs, the input will have a diagonal spring constant and friction equivalent to that of a conventional spring plate.

On the other hand, when the vehicle is running on a good road such as a highway, a small input of 15 mm or less lowers the diagonal spring constant and friction, resulting in a softer ride.

Conversely, if the converted displacement amount converted to the vertical displacement amount of the main plate l is K-W T, even if the input force is 15 mm or more to the spring plate, it will become softer than the conventional spring plate, so it will be difficult to corner the vehicle. The unsprung vibration increases due to rolling, rough roads, etc., and performance deteriorates.

For example, in Fig. 13, the displacement-load characteristics in the case of K-W T are shown, but the transition part (2
0mm) becomes longer, and the 2F at ±15mm amplitude decreases (from 2F' to 2F in the figure).If the 2F at 15mm decreases, stability against roll or damping against spring resonance on rough roads decreases. Sexuality worsens.

In addition, if the converted displacement amount of the above spring at the contact point A of the main plate 1 with the daughter plate 3 is 0.010 m, the deflection of the spring plate by adding the design standard load W is 10 mm or more, and the conventional It is equivalent to a spring plate, and becomes softer than a conventional spring plate with an input of 10 mm or less.

In addition, if the converted displacement amount converted to the vertical displacement amount of the main plate 1 is K-W T, even if the input to the spring plate is 10 mm or less, it will have the same hardness as a conventional spring plate, and it will not work on a good road. Favorable riding comfort cannot be ensured.

For example, in Fig. 14, the displacement-load characteristics in the case of K-W T are shown, but the transition part (5
mm) becomes shorter, and the diagonal spring constant does not decrease at small amplitudes of 10 mm or less.

Therefore, the diagonal spring constant of ±5 mm or more is equivalent to the conventional one, and in particular, the range where it is considered desirable to lower it to improve ride comfort, from ±5 mm to ±10 mm.
The spring constant will be the same as before.

The relationship between the above amplitude and 2F is shown in FIG. 15, and the relationship between the above amplitude and the diagonal spring constant is shown in FIG. 16.

In FIG. 15, when the amplitude X is plotted on the horizontal axis and 2F is plotted on the vertical axis, it is preferable that the amplitude X be within the range shown by diagonal lines up to ±15 mm, and that the amplitude X is 115 mm or less.
If the spring is larger than mm, the characteristics of a conventional upturned eye type stacked leaf spring may be sufficient. However, the area where the amplitude X is 115 mm or more is an area that affects roll and unsprung movement on rough roads.

In Fig. 16, when the horizontal axis is plotted with the amplitude It is better to lower it than the eye-type stacked leaf spring.

However, 2F is the width of recovery when the hysteresis loop of the spring is determined, and is an element that determines the damping performance of the spring unit. If the above-mentioned resurrection convergence 2F is small,
Damping properties deteriorate. It is possible to compensate with a shock absorber, but the damping force of a leaf spring is much greater than the damping force of a shock absorber, and the damping force of the shock absorber alone cannot compensate. Therefore, when used with a large amplitude, it is better to have a larger reanimation width 2F. On the other hand, if the width 2F of the above-mentioned revival is large, the diagonal spring constant will increase. Therefore, when used with a small amplitude, the reanimation width is 2F.
It is better to make it as small as possible.

Further, the diagonal spring constant is a characteristic that affects the vibration performance of the spring, and can be regarded as a dynamic spring constant.

A high diagonal spring constant results in a stiff spring, and a low diagonal spring constant results in a soft spring. In the case of stacked leaf springs, the presence of large friction (equivalent to 2F) increases the diagonal spring constant at small amplitudes, resulting in a stiff and uncomfortable ride. Therefore, in order to lower the diagonal spring constant at small amplitudes, it is necessary to lower 2F at small amplitudes.

From the above, for the stacked leaf spring according to the present invention, the amplitude
In the above, it is preferable that 2F be the same as that of a conventional stacked leaf spring, and in order to improve the ride comfort of the vehicle on good roads and connecting circuits, if the amplitude It is preferable to lower the constant than that of a conventional stacked leaf spring. To illustrate this graphically, the 17th
The result will be as shown in FIG. Here, when the rotation angle of the eyeball portion is converted into the displacement JiX at the contact site between the end plate and the daughter plate in contact with the end plate and the converted displacement amount of the spring is expressed as S, the following equation is obtained.

The value of the converted displacement amount S of the spring, and the vertical axis is the amplitude X of ±15
Plot the value of 2F in mm. That is, the amplitude X is ±1
In order to ensure that the 2F at 5 mm or more is equivalent to that of a conventional stacked leaf spring, the vertical displacement amount S of the spring should be 0.015 m.
Must be less than or equal to

In Fig. 18, the value and amplitude of the converted displacement amount S of the spring are ±
Showing the relationship between the diagonal spring constant at 10 mm, the horizontal axis is the value of the converted spring displacement 1 s, and the vertical axis is the amplitude X of ±10 mm.
Plot the value of the diagonal spring constant at . That is, the amplitude
In order to lower the diagonal spring constant when the distance is ±10 mm or less, the converted displacement amount S of the spring must be 0.010 m or more.

Therefore, the main plate 1 constituting the stacked leaf spring according to the present invention
It is preferable that the structure is such that the converted displacement amount of the spring plate satisfies the following equation.

Kw T In Fig. 17, the value and amplitude of the converted displacement amount S of the spring are ±
The relationship of 2F at 15mm is shown. Horizontal axis Kw
T [Effects of the Invention] The stacked leaf spring according to the present invention is configured as described above, and has the following effects. That is, this stacked leaf spring consists of a parent plate and a daughter plate that have eyes at both ends, and the contact area between the parent plate and the daughter plate adjacent to the parent plate does not relatively slip under load. The amount of displacement in which the contact portion of the plate is elastically deformed is converted into the amount of vertical displacement of the fulcrum of the central portion of the parent plate, and the converted amount of displacement is 0.010 m to 0.01.
Since it has a structure that is set to exist within a range of 5 m, the dynamic spring constant characteristics of the stacked leaf spring can be set to an ideal shape, suppressing the friction of the spring leaf at small amplitudes and providing a soft ride. Thus, it is possible to provide a stacked leaf spring which can obtain a high degree of stability, obtain a sufficient amount of friction with a large amplitude as in the conventional case, and provide a highly stable and rigid feeling.

That is, in the small amplitude region of the spring plate, the friction is reduced, and in the large amplitude region where the span change is large, characteristics dominated by normal sliding friction between the plates can be obtained. Therefore,
By applying the laminated leaf spring according to the present invention to a vehicle, it is possible to obtain ride comfort characteristics of the vehicle, especially ideal friction characteristics in a small amplitude region, thereby making it possible to obtain ideal friction characteristics in a small amplitude region. There is no need to control the damping force, and in the large amplitude wi range, it is possible to increase the friction more than before, which can have great effects such as reducing the need for stabilizers when rolling. .

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of a stacked leaf spring with a Berlin-shaped eye, Fig. 2 is an explanatory diagram showing an example of a stacked leaf spring with an amplifier turn door eye, and Fig. 3 is a schematic diagram showing an example of a stacked leaf spring with an amplifier turn door eye. FIG. 4 is an explanatory diagram showing a part of the main plate of the stacked leaf spring according to the present invention, and FIG. 5 is an explanatory diagram showing the operating state of the main plate and daughter plate. FIG. 6 is a diagram illustrating the amount of vertical displacement during wind-up of the main plate of the laminated leaf spring according to the present invention, and FIG. 7 is a diagram showing the load-deflection characteristics of the laminated leaf spring according to the present invention. 8 is a graph showing the relationship between the amplitude of the stacked leaf spring according to the present invention and the diagonal spring constant; FIG. 9 is a graph showing the relationship between the amplitude and friction of the stacked leaf spring according to the present invention; FIG. 10 is a graph showing the load-deflection characteristics of a conventional laminated leaf spring, Fig. 11 is a graph showing the relationship between the amplitude and diagonal spring constant of a conventional laminated spring, and Fig. 12 is a graph showing the amplitude and friction of a conventional laminated leaf spring. Fig. 13 is a graph showing the load-deflection characteristics of the laminated leaf spring according to the present invention, Fig. 14 is a graph showing the load-deflection characteristics of the conventional laminated leaf spring, and Fig. 15 is a graph showing the relationship between amplitude and 2F is an explanatory diagram showing the relationship between the amplitude and the diagonal spring constant. Fig. 17 is an explanatory diagram showing the relationship between the amplitude and the diagonal spring constant.
An explanatory diagram showing the relationship between 2F when the width is 5 mm, and FIG. 18 are explanatory diagrams showing the relationship between the converted spring displacement value and the diagonal spring constant when the amplitude is ±lQmm. 1, 1ll-----One main plate, 2.9--Eyeball, 3--Child plate, 4-----Center bolt, 6
・---1---Flat spring plate part, 7---Curved connection part, 10---U bolt. Idebetsu person Isuri Automobile Co., Ltd. agent Patent attorney O Naka - Family and disciple diagram diagram diagram diagram diagram diagram diagram amplitude - Kifukuichi diagram W$ Akira and 2F's heart α system diagram diagram diagram o , oos 0.0+0 S-ichiwao, oos 0.010 0.015 S□

Claims (1)

[Scope of Claims] (1) Consisting of a parent plate and a child plate having eyes at both ends, the contact portion between the parent plate and the child plate adjacent to the parent plate relatively slips under load. The amount of displacement in which the contact portion of the parent plate is elastically deformed without any movement is converted into the amount of vertical displacement of the fulcrum of the central portion of the parent plate, and the converted displacement amount is 0.010.
A stacked leaf spring having a structure set to exist within a range of m to 0.015 m. (2) The stacked leaf spring according to claim 1, wherein the converted displacement amount of the parent plate corresponds to the following formula. 0.010≦(μP・R'・R)/(Kw)・2・L/
T≦0.015, P: Contact force between the main plate and child plate when the design standard load W is applied to the entire spring plate, μ: Coefficient of friction between the spring plates, L: Contact point with the U bolt on the main plate distance T;U
Distance between the main plate and child plate at the bolt tightening part, R: Radius of the outer diameter of the center plate of the main plate, R': Distance between the center of thickness of the main plate and the contact point, Kw: Main plate Rigidity [T/θ (where θ is the rotation angle of the eye when torque T is applied to the eye of the main board)].