JPH0932874A - Waved spring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waved spring device which allows the use in a close contact and secures sufficient strength by forming projections and recessions on a circular base with a specified pitch in a circumferential direction, and satisfying a specified formula regarding the minimum radius of curvature of each of the projections and recessions. SOLUTION: A waved spring device has a circular base 5 on which a plurality of projections and recessions 6 are formed with a specified pitch. The projections and recessions 6 are prepared by continuously and alternate forming circular arcs, that is, projections 6a and recessions 6b each having the same radius of curvature. A minimum radius of curvature R1 of the projections and recessions 6 satisfies a formula 1. With such structure, the device can be arranged in a small space since the projections 6a and recessions 6b, being compressed to be flat, are not broken, allowing high load application. In the case that a strip-like material is bent to form the device, an abutting surface of the waved spring device can be arranged parallely to an object to be abutted. Surface abutting is allowed, so that increase of the pressure generated between both is suppressed, while both the device and the object are prevented from breaking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wave spring device used in, for example, an automatic transmission device of an automobile.

[0002]

2. Description of the Related Art For example, some transmissions and clutch mechanisms of automobiles incorporate a wave spring device as a spring for urging a clutch plate or the like. This corrugated spring device is, for example, as shown in FIG. 10, and has a ring-shaped metal spring base 1 provided with a plurality of peaks and valleys 2 at predetermined intervals along the circumferential direction.

As a method of manufacturing this wave spring, conventionally, the ring-shaped base is directly punched out from a metal plate material. However, since the yield of the material is very poor with such a method, recently, as shown in FIG.
A strip-shaped metal plate material 3 as shown in (a) is used, and this is bent into a C-ring shape as shown in (b) of the figure or a coil shape (multilayer) as shown in (c) of the figure. By doing so, a method of forming a wave spring device is generally performed.

Further improvements have been made on such a wave spring device.
Japanese Patent Publication No. 3 discloses a coil-shaped wave spring device in which the peaks and valleys are trapezoidal to prevent the peaks and valleys of the upper and lower layers from being displaced. In addition, JP-A-6-28
Japanese Patent No. 0912 discloses that the peaks and valleys have a clothoid curve shape to obtain linear load / deflection characteristics.

Further, Japanese Utility Model Laid-Open No. 60-3327 discloses that the radius of curvature on the inner peripheral side of the peaks and valleys is made larger than the radius of curvature on the outer peripheral side in order to make the stress on the inner and outer peripheral sides uniform. Has been done.

[0006]

By the way, each of the above-mentioned various wave spring devices is supposed to be used only in a completely linear characteristic state. That is, in general, the analysis of the characteristics of the wave spring device is performed by approximating a straight beam continuum in which the tops of the peaks 2 are point-supported.
No consideration is given to the state in which the ridges and valleys 2 are completely crushed into a flat plate shape and come into close contact with an object (close contact state).

For example, the corrugated spring device employing the clothoid curve (Japanese Patent Laid-Open No. 6-280912) focuses on maintaining the linearity of the load characteristics, and does not mention the contact state at all. . In addition, an application regarding the radius of curvature of the inner and outer peripheral portions of the spring (Actually published Japanese Utility Model Sho 60-332
In 7) as well, the optimum shape has not been clarified since there is no consideration for the time of contact.

Further, in the device having the trapezoidal ridges and valleys (Japanese Utility Model Laid-Open No. 60-3327), only a coiled wave spring device is assumed, and the ridges and valleys of each other are prevented in order to prevent the upper and lower layers from being displaced. The above is a close contact from the beginning, and does not assume a close contact state due to deformation during use.

On the other hand, in recent automobile automatic transmission devices and the like, the wave spring device is used after being compressed from the linear characteristic state to the close contact state (near the plate thickness) in order to save space and reduce weight. There is a circumstance that a corrugated spring device having an optimum shape is needed under such conditions.

On the other hand, as another problem, there is a problem that the cross-sectional shape of the corrugated spring device is deformed. That is, when the base material 1 of the corrugated spring device is formed by bending the band-shaped material 3 (FIG. 11A) as described above, the bending is performed as shown in FIG.
The one having a rectangular cross section as shown in Fig. 2 (a) has a compressive stress on the inner peripheral side during bending and a tensile stress on the outer peripheral side. As shown in b), the thickness of the inner peripheral side becomes larger than the thickness of the outer peripheral side, and the surfaces 1a and 1b of the base body 1 that come into contact with the target object.
May become an inclined surface.

It is generally known that the maximum stress in a cross section occurs at a position farthest from the neutral axis (indicated by T in the figure) of the cross section. Therefore, the internal stress generated in the corrugated spring device becomes uneven in the cross section, and the maximum internal stress occurs in the thickest part of the plate, that is, the inner peripheral side. Therefore, the wave spring device may be damaged from this portion.

Further, with such a shape, since the peaks and valleys 2 of the above-mentioned wave spring device cannot be brought into close contact with the object over the entire width in the width direction, not only the height dimension increases but also the contact portion ( Pressure (shown as A in the figure) rises abnormally,
Not only this wave spring device but also the object may be reached.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a corrugated spring device which is sufficiently assumed to be used in a close contact state and has sufficient strength. .

[0014]

A first means of the present invention is a corrugated spring device having a ring-shaped base and peaks and valleys provided at a predetermined pitch in the circumferential direction along the base. The wave spring device is characterized in that the minimum radius of curvature R1 of the mountain valley portion satisfies the following expression.

[0015]

(Equation 3)

A second means is the wave spring device according to the first means, wherein the annular base body is formed by bending a band-shaped material around an axis parallel to the plate thickness direction of the material. This strip-shaped material is a wave spring device characterized in that the plate thickness of the portion on the inner peripheral side of the base body and the plate thickness of the portion on the outer peripheral side thereof satisfy the following equation.

[0017]

(Equation 4)

According to the first means, the corrugated spring device can be compressed to a substantially plate thickness so that the peaks and valleys can be brought into close contact with the object in a substantially flat shape. Since it can be kept low, it is possible to effectively prevent the wave spring device from being damaged.

According to the second means, when the corrugated spring device is formed by bending a band-shaped material, the cross-sectional shape can be kept substantially rectangular even after the bending. Therefore, when compressed, it can come into close contact with the object in a planar manner, so that the pressure per unit area applied to the corrugated spring device and the object can be suppressed low.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a perspective view showing the wave spring device of the present invention. This corrugated spring device has a ring-shaped (annular) base 5, and a plurality of peaks and valleys 6 ... Are formed on the base 5 at a predetermined pitch P. The peaks and valleys 6 are two arcs (peaks 6a) having the same radius of curvature.
And the valleys 6b) are connected to each other with the convex directions reversed.

FIG. 1 (b) is a side view showing a state in which this wave spring device is provided in an automatic transmission device of a passenger car. In the figure, reference numerals 7 and 8 represent one and the other pressing bodies provided in the automatic transmission device. In the automatic transmission device, the pair of pressing bodies 7 and 8 are pressed in a direction in which they are close to each other (a direction indicated by a white arrow in the figure) to compress the wave spring device (mountain valley portion 6). .

2 (a) to 2 (c) are side views showing the top of the valley portion 6b of the wave spring device in an enlarged manner. In addition,
The crests 6a have the same shape as the troughs 6b, and the description thereof will be omitted.

FIG. 5A shows a non-compressed state, in which the radius of curvature of the valley portion 6b is R1. The other pressing body is shown at 8 in the same figure. Further, FIG. 7B is an enlarged view showing a state where the waveform spring device is sandwiched by the one and the other pressing bodies 7 and 8 and the compression is started. At this time, an external force indicated by an arrow (a) in the figure is input to the valley portion 6b, and the other pressing body 8 is
The highest stress is generated at the top of the valley 6b in contact with.

The magnitude of this stress is generally analyzed as follows. That is, the wave spring device is approximated to a continuous body of straight beams in which this portion is point-supported, and the maximum stress of this portion is expressed by the following equation (1) from the material mechanics formula.

[0025]

(Equation 5)

Here, E is the Young's modulus, t is the material plate thickness, n is the number of peaks per turn, D is the diameter of the spring, and δ is the displacement. The above formula (1) is a formula that holds only when the wave spring device is point-supported at the apex of the valley portion 6b (ridge portion 6a), but the wave spring device is further increased by a large compression force. When compressed, as shown in FIG. 2C, the radius of curvature of the valley portion 6b becomes infinite as the compressive force increases.

Here, the infinite radius of curvature means that the valley portion 6b becomes a flat plate shape as shown in the same figure and comes into close contact with the other pressing body 8, and the radius of curvature does not change any more. Say. At this time, the stress σ generated inside the valley portion 6b (close contact portion) is expressed by the following equation (2) from the change amount of the radius of curvature (R1 → infinity) up to that point. The stress σ at this time becomes a substantial maximum stress value generated in the wave spring device. Therefore, assuming that the allowable stress of the material is σ B, the minimum value of the radius of curvature that can be taken is given by the following expression (3).

[0028]

(Equation 6)

On the other hand, the shape (radius of curvature) of the wave spring device is also limited by space conditions and load characteristics. First, the spring diameter (D), the number of peaks (n), etc. are determined from the load characteristics. In addition, the effective mountain height (free height) (h) from the space between the two pressing bodies 7 and 8 (see FIG. 1B).
3 is drawn, the maximum radius of curvature R that can be taken by the valley portion 6b (peak portion 6a) can be geometrically determined. That is, under the above conditions, if the curvature of the peaks 6a and the valleys 6b is made larger than shown in the figure, the connecting portion between the peaks 6a and the valleys 6b is displaced, and the radius of curvature of this portion is expressed by the above formula (3). This is because it may be smaller than the value. From this figure, the following conditional expression (4) can be derived.

[0030]

(Equation 7) From this equation (4) and the above equation (3), the radius of curvature R1 of the valley portion 6b (peak portion 6a) of the wave spring device is
It suffices if it is within the range shown by the following equation (5).

[0031]

(Equation 8)

In a general (conventional) corrugated spring device, the peaks of the peaks and valleys need to be in point contact with the pressing body at all times even in a deformed state. Therefore, as shown in FIGS. , Radius of curvature at the top of the mountain valley (Ra, Rb in the figure
(Shown by) is set to a fairly small value. On the other hand, in the wave spring device of the present invention, as described above, it is assumed that the peaks and valleys 6 are flat and come into close contact with the pressing bodies 7 and 8. Therefore, the minimum radius of curvature that can be taken is Et. This is / 2σB or more, which is considerably larger than the minimum radius of curvature of the conventional wave spring device as will be described later.

Further, in the wave spring device of the present invention, the shape of the connecting portion between the peak portion 6a and the valley portion 6b (the shape of the portion indicated by B in FIG. 3) must also be not less than the radius of curvature Et / 2σB. If this condition is satisfied, the shape of this connecting portion is not particularly limited, and may be a linear shape.

The dimensions of the preferred embodiment of the invention are shown in the table of FIG. In addition, the same design conditions (spring diameter, plate width,
Conventional product 1 and conventional product 2 designed with the number of peaks and free height
Shows the facts of. Conventional product 1 has a radius of curvature (minimum) at the top so that the amount of bending (thickness: 2.15 mm) is equal under the same load (340 kgf) as the product of the present invention under the formula (1) (conventional design ideal formula). The radius of curvature) and the plate thickness are determined, and in the conventional product 2, the radius of curvature at the apex is determined so that almost all dimensions including the plate thickness are equal to those of the product of the present invention. The curved shape of the peaks and valleys 6 of the product of the present invention is a shape in which arcs having the same radius of curvature are connected by a straight line portion. In both the conventional products 1 and 2, the curved shape of the peaks and valleys is a sine curve (see FIG. The shape is similar to that shown in.

As shown in the table, the minimum radius of curvature of the present invention is the smallest value calculated under the above equation (5) and is 1
While it is 74.6 mm, the conventional products 1 and 2 are considerably smaller than these, and are 57.6 mm and 9 respectively.
It is 8.7 mm. Further, the lowermost part of the table shows the maximum value of the internal stress in the valley portion 6 when the same load (340 kgf) is applied.

In the case of the product of the present invention, the above load (340 kg
When f) is added, the thickness is the plate thickness (2.05 mm)
2c, the peaks and valleys 6 are substantially crushed and are in close contact with the pressing body as shown in FIG. On the other hand, the conventional product 1 designed by the conventional method has the same load and the same bending amount as shown in the above table, but the internal stress is 2 more than that of the product of the present invention.
It is 0% bigger.

Further, regarding the conventional product 2 having a plate thickness larger than that of the conventional product 1 and having the same plate thickness dimension as the product of the present invention, when the same load is applied, the internal content is 17% larger than the product of the present invention. There is stress.

That is, when the stress characteristics of the product of the present invention and the conventional product 1 are examined, the results are shown in the graph of FIG.
While the stress characteristic of has linearity up to the limit state,
In the product of the present invention, since the peaks and valleys 6 are crushed into a flat plate shape with a relatively low load, the increase in stress is saturated, and the increase in internal stress is suppressed even when the same load is applied.

With this structure, the effects described below can be obtained. That is, the minimum radius of curvature of the peaks and valleys 6 of the wave spring device is set on the assumption that the peaks and valleys 6 are almost completely crushed and brought into close contact with the pressing bodies 7 and 8. Even when is crushed to near the plate thickness, the internal stress value can be considerably reduced compared to the conventional product.

Therefore, the durability of the corrugated spring device can be improved in the above-mentioned usage state, and the degree of freedom in designing can be increased accordingly. That is, as compared with the conventional wave spring device, the plate thickness can be made thinner and the plate width can be made smaller, so that the space occupied by the wave spring device can be reduced and the weight can be reduced.

As a result, the automatic transmission device for passenger cars, which has recently been required to be compact and space-saving, can be sufficiently dealt with, which can contribute to the achievement of the object such as the miniaturization of the device.

Further, as described above, the waveform spring device of the present invention has a considerably high endurance load. Therefore, a place where a plurality of waveform spring devices are conventionally loaded is replaced with one waveform spring device. It is also possible.

As a result, the number of parts in the product which conventionally uses a plurality of wave spring devices is reduced, and the assembly is facilitated. The wave spring device of the present invention can also be formed by bending a band-shaped material as described in the section of the conventional example. In this case, in the present invention, the cross-sectional shape of the material is shaped so that the plate thickness of the corrugated spring device after bending is substantially constant over the entire width.

That is, as explained in the section of the conventional example,
When the band-shaped material is bent, a compressive stress acts on the inner peripheral side of the material and a tensile stress acts on the outer peripheral side thereof, so that the sectional shape of the wave spring device after molding is distorted as shown in FIG. 12 (b). I will get out.

When the product is used within a range in which the peaks and valleys are not crushed as in the conventional product, the pressure generated between the peaks and valleys and the object with which the peaks and valleys contact is not so large. The cross-sectional shape as shown in FIG. 12 (b) does not have a great influence. However, in the case of the corrugated spring device of the present invention, it is expected that a larger load will be applied as described above. Therefore, in the cross-sectional shape as described above, the unit generated between the peaks and valleys and the pressing body is The pressure per area can be quite high. Therefore, this wave spring device or the pressing body may be damaged.

Therefore, in the present invention, as shown in FIG. 8 (a), the thickness to of the portion of the strip-shaped material 10 on the outer peripheral side of the base 5 after formation is set to the portion on the inner peripheral side after formation. The thickness is set to be larger than the thickness t i. As a result, a tensile stress is applied to the outer peripheral side and a compressive stress is applied to the inner peripheral side during bending, so that the sectional shape of this wavy spring device becomes rectangular after bending as shown in FIG. 8B. For this purpose, it is sufficient to set the above-mentioned to and ti to the values shown in the following formula (6) from the formula of material mechanics.

[0047]

[Equation 9] Here, Do is the outer diameter of the wave spring device, W is the plate width,
tc is an average plate thickness of the material 10 (designed plate thickness of the base 5).

With such a structure, it is possible to obtain a wave spring device having a rectangular cross section with an average plate thickness tc after molding. Therefore, even when a high pressure is applied, the corrugated spring device and the pressing body 8 (7) can be brought into close contact with each other over the entire width, so that the pressure per unit area generated between them can be reduced. it can. Therefore, it is possible to effectively prevent the wave spring device and the pressing body 8 from being damaged.

The present invention is not limited to the above-described one embodiment, and can be variously modified without changing the gist of the invention. For example, in the above-described one embodiment, the wave spring device is provided in the automatic transmission device of the passenger car, but the invention is not limited to this. It may be provided in another device.

Further, in the above-described one embodiment, the wave spring device has one winding, but the invention is not limited to this. You may make it comprised by multiple winding like the prior art example shown in FIG.11 (c).

Furthermore, the peaks and valleys 6'may have a shape as shown in FIG. In this wave spring device, the mountain portion 6 '
Although a has the same shape as that of the above-described embodiment, the top of the valley portion 6'b is flat unlike the above-described embodiment. Even in such a shape, as long as the minimum radius of curvature of the curved portion satisfies the above expression (5), the same effect as in the above-described embodiment can be obtained.

[0052]

According to the structure described above, the corrugated spring device of the present invention does not break even when the peaks and valleys are completely crushed and compressed into a flat plate state, so that it can be installed in a narrow space. There is an effect that it can be provided and can receive a higher load.

Further, even when the band-shaped material is bent and formed, the contact surface of the corrugated spring device can be made parallel to the object to be contacted and can be surface-contacted. It is possible to suppress an increase in pressure generated between the two and effectively prevent damage to the corrugated spring device and the object.

[Brief description of drawings]

FIG. 1 is a perspective view and a side view showing an embodiment of the present invention.

FIG. 2 is also an enlarged process diagram showing the operation.

FIG. 3 is a schematic diagram showing dimensions as well.

FIG. 4 is a process diagram similarly showing the operation of the conventional wave spring device.

FIG. 5 is a process drawing similarly showing the operation of the conventional wave spring device.

FIG. 6 is a table similarly comparing the performance of the present invention product and the performance of the conventional product.

FIG. 7 is a graph similarly comparing the stress characteristics of the present invention product and the conventional product.

FIG. 8 is a schematic perspective view showing a sectional shape of the same.

FIG. 9 is a side view showing another embodiment.

FIG. 10 is a perspective view showing a conventional example.

FIG. 11 is a perspective view showing a conventional example.

FIG. 12 is a schematic perspective view showing a sectional shape of a conventional example.

[Explanation of symbols]

5 ... Base, 6 ... Mountain valley, 6a ... Mountain, 6b ... Valley, R1
…curvature radius.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Nagaishi 4056 Sakuradai, Nakatsu, Aikawa-cho, Aiko-gun, Kanagawa Japan

Claims (2)

[Claims] 1. A corrugated spring device having an annular base and peaks and valleys circumferentially provided along the base at a predetermined pitch, wherein the minimum radius of curvature R1 of the peaks and valleys satisfies the following equation. A wave spring device characterized by the above. [Equation 1] 2. The corrugated spring device according to claim 1,
The annular base body is formed by bending a band-shaped material around an axis parallel to the plate thickness direction of the material, and the band-shaped material is formed on the inner peripheral side of the base body. A corrugated spring device, characterized in that the plate thickness and the plate thickness on the outer peripheral side satisfy the following equation. [Equation 2]