JPH03258656A - Rolling stock four wheel truck - Google Patents

Abstract

PURPOSE:To improve the self-steering performance at the time of curve turning by making the elastic force acting on the relative yawing displacement between a front wheel set and a truck frame smaller than that of the rear wheel set, and providing a damping force working element acting on the relative yawing speed between the front wheel set and the truck frame. CONSTITUTION:In a rolling stock four wheel truck in which a front wheel set 2 and a rear wheel set 3 are rotatably supported by a truck frame 1 through respective shaft boxes, the longitudinal shaft box supporting rigidity 6 of the front wheel set 2 is set smaller than the longitudinal shaft boxy supporting rigidity 7 of the rear wheel to the advancing direction. Namely, the elastic force acting on the relative yawing displacement between the front wheel set 2 and the truck frame 1 is made smaller than that of the rear wheel set 3. A damping force working element 8 acting on the relative yawing speed between the front wheel set 2 and the truck frame 1 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a bogie that is a running device for a railway vehicle. The functions required of a bogie include vehicle support, drive,
One of the three is guidance, and one of them is the invention of a trolley that dramatically improves the performance of the guidance function. In other words, it is a bogie that achieves both self-steering performance when turning around curves and high-speed running stability. The bogie according to the present invention can dramatically improve the self-steering performance of the wheel set in the radial direction of the curve when turning a curve while maintaining the stability of meandering behavior at high speeds.

(Prior Art) In conventional two-axle bogies for railway vehicles, the left and right wheels are rigidly connected, and a wheel axle is used in which the left and right wheels rotate at the same speed. It has become. That is, the axle box support rigidity, the damping force acting element, the link mechanism that connects the wheel axles, the link mechanism that connects the bogie frame and the wheel axle, etc. are symmetrical in the front and rear.

(Problems to be Solved by the Invention) This conventional type of bogie has the following drawbacks regarding the guiding function of the bogie. That is, the self-steering performance when turning a curve is not sufficient, and if the radius of the curve is small, the wheel axle cannot be sufficiently steered, causing a large lateral pressure. Furthermore, flange contact is less likely to occur, causing flange wear and noise. On the other hand, if an attempt is made to improve the self-steering performance when turning around a curve, the critical speed at which snaking behavior, which is a type of self-excited vibration, occurs will decrease, resulting in a decrease in stability at high speeds.

The object of the present invention is to solve the above-mentioned drawbacks and to dramatically improve the self-steering function when turning curves while maintaining the meandering stability at high speeds that is sufficient for practical use.

First, we will explain how conventional bogies perform self-steering when turning around curves, how snaking behavior occurs, and how it is conventionally prevented. Then, it will be explained that the conventional method for preventing snake movement reduces self-steering performance when turning around a curve.

(Self-steering function of conventional bogie) The left and right wheels are rigidly connected, and the contact surfaces of the wheels with the rails, that is, the wheel treads, are sloped. Therefore, when the wheel set turns along a curve, the wheel set is displaced to the outside of the curve, and even though the rotational speeds of the left and right wheels are the same, the turning radius of the wheel becomes larger for the wheel on the outer track, and the wheel can roll without slipping.

This is the principle behind the wheel set's self-steering function. Furthermore, this function also produces a restoring action to return the motion of the wheel set to its original motion when disturbances such as track irregularities occur even when traveling in a straight line.

However, such a self-steering function and restoring function of the wheel axle heavy body may cause snaking behavior, making the movement of the bogie unstable. Therefore, the bogie frame and wheel axle are connected by an axle box support rigidity that elastically restrains relative yawing motion.

(Snaking behavior generation mechanism) The forces acting on the wheel set from the rail that cause snaking behavior are a lateral creep force determined by the yaw angle with respect to the wheel's traveling direction, and a vertical creep force that depends on the slip between the wheel and the rail in the traveling direction. . The former is a force that is generated in the left and right directions when the wheel set yaws or steers. The latter is a force in the opposite direction of travel between the left and right wheels that is generated when the wheel axle is displaced in the left-right direction because the rotational speeds of the left and right wheels are equal, causing slippage due to the difference in the rotation radius of the left and right wheels. The force creates a moment that causes the wheelset to yaw.

(Method for preventing snake motion in conventional bogies) In order to prevent snake motion in conventional bogies, in order to balance these creep forces, the elastic force from the axle box support rigidity acting on the axle box and the damping force acting element are applied to the axle box. Apply damping force. However, among the longitudinal creep force and the lateral creep force, the force that depends on the lateral speed and yawing speed of the wheel set is almost inversely proportional to the traveling speed, so as the speed increases, the effect of damping the speed-dependent meandering motion of the wheel set is reduced. It becomes smaller. The decrease in damping force causes automatic vibration, which causes a snake motion that makes the movement of the truck unstable. The critical speed at which this meandering behavior occurs and the motion of the wheel set becomes unstable is called the critical speed, and in practice, this critical speed must be greater than the operating speed. A method conventionally used for this purpose is to increase the longitudinal axle box support rigidity that restrains the yawing movement of the wheelset.

(Reason why the conventional bogie snaking prevention method reduces the self-steering function) When the longitudinal axle box support rigidity increases, the self-steering performance on curves decreases as explained below (see Figure 4 (b)) .

(a) First, let's consider a situation where the front and rear wheelsets are completely steered in the radial direction of the concave line.

(17) Since a relative yawing displacement occurs between the front wheel axle and the bogie frame, a moment is generated at the front wheel axle in a direction that hinders steering due to the longitudinal axle box support rigidity.

Similarly, a moment in the opposite direction acts on the rear wheel axle.

Since these are internal forces through the bogie frame, they must be in opposite directions and equal in magnitude.

(c) To balance these moments, a longitudinal creep force must act on both wheel axles.

For this purpose, the front wheel axle is displaced outward and the rear wheel axle is displaced inward. Therefore, the front and rear wheel axles undergo relative left-right displacement.

(d) On the other hand, as shown in (I7), the yawing moment due to the axle box support rigidity due to yawing must be equal between the front and rear axles, so the bogie frame does not yaw.

(e) Therefore, from (c) and (d), a relative left-right displacement occurs between the wheel axle and the bogie frame, and due to the support rigidity of the axle box in the left-right direction, the front wheel axle will move inward in the curve, and the rear wheel axle will move outward in the left-right direction. Receive power.

(f) This lateral force must be balanced with the lateral force between the wheels and the rail. This force is a lateral creep force, and does not occur unless there is a yawing displacement of the wheel axle in the opposite direction to the steering from the steering state of the wheel axle in the curve radial direction.

(g) In other words, due to the existence of longitudinal axle box support rigidity,
It is not possible to completely steer the wheelset. In Figure 4(b),
This figure shows the displacement of the wheels and truck frame when a conventional truck is turning around a curve.

If the curve radius is small and the longitudinal axle box support rigidity is large,
The yaw moment acting on the wheel set increases. Therefore,
The outward displacement of the front wheel axle becomes even larger, and if the flange clearance is narrow, the flange will come into contact with the outer raceway.

Flange contact not only leads to wear of flanges and rails, but also causes noise.

(Means for Solving the Problems) The present invention solves the above drawbacks. In conventional bogies, one of the causes of deterioration in the method of preventing snaking behavior and the self-steering function when turning around curves is the longitudinal symmetry of the bogie configuration. Therefore, the basic solution of the present invention is to make the structure of the truck asymmetrical in the front and rear.

In the present invention, the problem is solved by the two means of claims (1) and (3). That is, in claim (1),
As shown in FIG. 1, this is a bogie in which the front axle has a front-rear axle box support rigidity smaller than that of the rear axle, and is further equipped with a damping force effecting element that generates a resistance force against the fast yawing motion of the front axle. Claim (2) is a method for specifically realizing a trolley that satisfies claim (1) when the traveling direction changes back and forth, and includes a damping force applying element that can switch the damping force as shown in FIG. This is a bogie that is installed longitudinally between the bogie frame and axle box. Claim (3), as shown in FIG. 3, uses wheels that allow the left and right wheels to rotate together only on the rear axle, and further includes a component that exerts restraint on the relative lateral displacement and speed of the front and rear axles on the front and rear axles. It is an asymmetrical cart that is shifted back and forth from the center point.

(Function) Hereinafter, it will be explained that the problems of conventional trolleys can be solved by the method according to the present invention.

(Operation of the bogie according to claim (1)) Fig. 4(a) shows the displacement of the wheel set and the bogie frame when the bogie according to claim (1) is turning around a curve. As shown in the above (Reason why the method for preventing snake motion of conventional bogies reduces the self-steering function), in conventional bogies, the presence of longitudinal axle box support rigidity hinders the self-steering function of the wheelset. ) is the existence of a lateral force acting on the axle box. Therefore, the truck structure may be such that no lateral force is applied due to the rigidity of the axle box support in the lateral direction. To do this, the bogie frame should be yawed so that the axle box left-right direction force (e) is not applied as much as possible. That is, in order to attach the support rigidity of the axle box in the left-right direction to the bogie frame, the bogie frame may yaw so that the left-right displacement at the position is approximately equal to the left-right displacement of the axle mentioned above. The front axis is on the outside of the curve,
Since the rear axle is displaced to the inside of the curve, the bogie frame will yaw to the right if it is turning left. Therefore, the relative yawing displacement between the front axle and the bogie frame is larger than the relative yawing displacement between the rear axle and the bogie frame. As shown in (d), the yawing moment caused by the longitudinal axle box support rigidity caused by these relative yawing displacements must be equal. For this purpose, this condition is met if the front and rear axle box support rigidities in the longitudinal direction are different in magnitude between the front and rear wheel axles. That is, it is sufficient that the axle box support rigidity in the longitudinal direction between the front axle and the bogie frame is smaller than the axle box support rigidity in the longitudinal direction between the rear axle and the bogie frame. The above is the explanation of the effect according to condition (a) of claim (1). By appropriately making the longitudinal axle box support rigidity of the front wheel axle smaller than that of the rear axle, ideally the front and rear wheel axles can be completely self-steering in the radial direction of the curve.

However, if only this condition is met, the axle box support rigidity of the front axle in the longitudinal direction becomes small, and the stability against the snaking motion of the front axle decreases. A means for preventing this is the condition ([+) of claim (1). As explained above (mechanism for generating snaking behavior), snaking occurs when the creep force determined by the yawing speed of the wheel set decreases as the speed increases. Therefore, a damping force acting element that acts between the wheel set and the bogie frame is provided to compensate for this damping force, thereby preventing snaking. Note that in conventional bogies, damping force acting elements are used as lateral movement dampers and yaw dampers between the bogie frame and the vehicle body, but no damping force acting elements are used at this position.

This damping force effecting element generates a larger resistance force as the speed increases, so high frequency vibrations such as snake action,
In other words, a large force acts on a movement with a high yawing speed and is effective, but yawing due to steering during curved turns is a slow movement.
It doesn't provide much resistance. Since no resistance is generated when the yawing speed is zero, self-steering performance is not affected at all when the vehicle is constantly turning around a curve. Therefore, it is possible to perform almost perfect self-steering when turning a curve, which has been impossible with conventional bogies, and to ensure sufficient stability in meandering behavior.

(Operation of the truck according to claim (2)) Since the truck satisfying claim (1) is asymmetrical in the front and rear,
When traveling in both directions, it is necessary to switch the front-rear axle box support rigidity depending on the direction of travel, and to change the attachment of the damping force acting element that acts in the front-rear direction. Claim (2) is a cart that allows this operation to be performed easily. That is, this can be achieved by simply attaching a damping force effecting element whose damping force can be switched as shown in FIG. The damping force of the damping force acting element on the side that becomes the rear shaft with respect to the traveling direction is switched so that it becomes extremely large. When the damping force is very large, the relative displacement between the wheel set and the bogie frame is restrained, and both move like rigid bodies. In other words, the axle box support rigidity of the rear axle in the longitudinal direction is equivalently increased.

The front axle has a damping effect and has a smaller value than the front-rear axle box support rigidity of the rear axle, which is claimed in claim (1).
The trolley satisfies the following conditions.

(Function of the bogie according to claim (3)) The present invention is a second means for solving the problem that the conventional method for preventing the snake motion of a bogie impedes the self-steering function of the wheelset.

That is, in addition to making the support structure of the wheel axle inside the bogie asymmetrical, in order to further stabilize the meandering motion, a front-rear asymmetry is introduced using wheels that allow left and right wheels to rotate together only on the rear axle.

When these independently rotating wheels are used, the left and right wheels can rotate at the same speed, which greatly reduces slippage between the wheels and the rails. Therefore, the longitudinal creep force that acts between the wheels and the rails, which causes snaking motion, becomes extremely small, the critical speed increases, and the running stability improves. However, at the same time, the self-steering function of the wheelset is also lost.

3 4 Therefore, claim (3) uses independent rotating wheels only on the rear axle in the direction of travel, and uses independent rotating wheels on the front axle in order to take advantage of the improved running stability of independently rotating wheels and maintain the self-steering function of the bogie. The idea is to use an ordinary wheel set that has a self-steering function.

(Asymmetric wheel axle support mechanism according to claim (3)) In order to improve the self-steering function of the front axle, the support mechanism for the front axle and the support mechanism for the rear axle are different from each other as in claim (1). do. Here, as shown in Fig. 5, the mechanism for restraining the longitudinal and lateral movement of the wheel axle is not only the longitudinal axle box support rigidity that acts between the bogie frame and the axle box, but also the mechanism that acts between the wheel axle and the bogie frame. Also consider link mechanisms that directly connect the front and rear wheel axles, and consider equivalent support rigidity.

For various bogie structures such as those shown in Fig. 5, if we focus only on the displacement of the rear shaft with respect to the traveling direction, we can replace the equivalent bending stiffness kb and the equivalent shear stiffness kse with the equivalent curve as shown in Fig. 6. I can think about it. The longitudinal asymmetry when considered in terms of this equivalent support stiffness, which restrains the motion of a general wheel set, is
It can be expressed as the deviation of the point of action of equivalent shear stiffness from the center point of the longitudinal axis.

This is called an anteroposterior asymmetry index and is expressed as as. This value assumes a positive value when moving forward in the direction of travel.

In the case of each bogie shown in FIG. 5, the front-rear asymmetry index, equivalent bending stiffness, and equivalent shear stiffness are expressed by the following equations.

(b) Bogie shown in Figure 5(a): It has the same configuration as the conventional bogie, but 1) It is a bogie where the axle box support rigidity in the rear direction is yt in the front and rear directions, and the axle box support rigidity in the front and rear direction of the front axle is is kxl, the front-rear axle box support rigidity of the rear axle is bx2, and the left-right axle box support rigidity of the front-rear axle is ky.

as = −a(kxl −bx2)/(kxl +
bx2) kb = 2 kxl bx2 bx2/
(kxl + bx2) kse = ky (kxl
+ bx2) bx2/(2a2ky + (kxl
+ bx2) bx2) (b) Bogie shown in Figure 5(b): This is a bogie in which the wheel axle and the bogie frame are connected by a link, and the distance between the center of yawing rotation of the wheel axle and the wheel axle by the link is different for the front and rear axles. This distance for the front axle is 81, this distance for the rear axle is a2 (if the center of rotation is on the rear side, the sign is negative), the rigidity of the link is kO1, and the longitudinal axle box support rigidity of the front and rear axle is kx. do.

as=(al+a2)/2 kb=kxbxλ kse=kOkx bx2/[(a +
(al −a2)/2) kO+ kx bx
``l (C) Bogie in Figure 5 (C): This is a bogie in which the front and rear wheel axles are connected by links, and the intersection of the links is offset from the center.This forward shift is calculated by aSC ((& (the deviation is negative), the rigidity of the link is ks, and the axle box support rigidity in the longitudinal direction of the longitudinal axis is kx.

as=asc kb=kx bx''kse=ks Note that the axle box support rigidity and link rigidity are each the rigidity per one wheel axle.The same is true for the damping force acting element.

(Example) Figure 7.8 shows the results of calculating the critical speed for snaking behavior and self-steering performance during curved turns for the bogie of the present invention. FIG. 7 shows the performance of the cart according to claims (1) and (2), and FIG. 8 shows the performance of the cart according to claim (3).

FIG. 7(a) is a comparison of the self-steering performance of the carts according to claims (1) and (2) and a conventional cart. 84 from straight section
The radius of curvature is 400m and the amount of cant is 210m after passing through a transition curve of m.
A curve section with a steady curvature of mm at a speed of 100 km/
This shows the left and right displacement and yawing displacement of the wheel axle when traveling at h. The lateral displacement is defined as the inward displacement from the center of the track, and the yawing displacement is the yawing displacement from the state where the wheel set is completely steered and the wheel set is steered in the radial direction of the curve.In other words, it is expressed as the attack angle. It was assumed to be a positive displacement.

That is, when the angle of attack is zero, complete steering is occurring. In the conventional truck (indicated by the broken line), flange contact occurs even though the steering is not performed sufficiently. On the other hand, in the stand according to the present invention (indicated by a solid line), self-steering is performed in an ideal manner, and flange contact can also be avoided.

FIG. 7(b) is a calculation result of the critical speed at which snaking behavior occurs for the carts according to claims (1) and (2).

The horizontal axis represents the longitudinal axle box support rigidity of the rear axle per one wheel axle, and the vertical axis represents the horizontal axle box support rigidity of the longitudinal axle per one wheel axle, and the contour lines of the critical speed are shown as solid lines. . The broken line indicates the ratio of the front-rear axle box support rigidity of the front-rear axle. In this calculation example, the axle box support rigidity of the rear axle in the longitudinal direction is approximately 106 N/m.
Accordingly, the axle box support rigidity of the front axle in the longitudinal direction is approximately 0.2 to 0.4 times that of the rear axle, and the axle box support rigidity in the left and right direction is increased to 1.
If you select around 06N/m, the speed will be 288km/m.
It can be seen that no snaking behavior occurred up to h, and there is no practical problem in normal railways.

Note that the calculations here were expressed using linear equations of motion, and the constants of the truck were set to commonly used values, and the following values were used.

Wheel axle mass: 1525 kg, wheel axle yawing moment of inertia: 461.3 kgm2, gauge: 1067 m
m, axle box installation distance: bx = 0.82m, half of wheelbase: a = 1.05m, wheel rotation radius: r = 0.43
m, wheel tread slope: λ = 0.1, vertical creep coefficient: to]
, = 5.6-x'lo N, lateral creep coefficient: 2 = 5
．． 0X10”N, bogie frame mass: 3400kg, bogie frame yawing moment of inertia: 2877.8kgm2
, pillow spring lateral stiffness: 6.86X10ゝN/m, lateral damper damping coefficient: 10 Ns/m, yaw damper damping coefficient: 2ylO'Nm50 Regarding Fig. 7(a), furthermore, the per wheel axle of the conventional bogie Axle box support rigidity in longitudinal and lateral directions; kx・107N/m ky=5glo N7m
, for the bogies of claims (1) and (2), the left-right direction axle box support rigidity per one wheel axle: ky5x10ゝN/m, 1
Front axle longitudinal axle box support rigidity per wheel axle: kxl・1
．． 43x106N/m, rigidity of the same rear shaft: kx2=10
7N/m, damping coefficient per wheel axle of damping force acting element = 5
xlO'Ns/m, distance: O, '82m was used for the same installation. Further, in FIG. 7(b), the value of the axle box support rigidity of the front axle in the longitudinal direction is determined by the following formula so that the self-steering performance is calculated to be optimal. This optimum condition does not depend on the radius of curvature of the curve.

as=abλ kx2 / (2a to I^ +kx2
b r) kxl = kx2 (a - as') /
(a + as) FIG. 8 shows the condition that the self-steering angle in the steady state is satisfied by 80% of the perfect steering state when the bogie according to claim (3) turns on a curved trajectory having an arbitrary curvature. , the critical speed of snake movement was determined by changing the equivalent support stiffness. Figure 8(a) shows the case where the rear axle is an independently rotating wheel as in conditions (A) and (D) of claim (3), with the equivalent shear stiffness on the vertical axis and the equivalent bending stiffness on the horizontal axis. The contour lines of the critical velocity are shown as solid lines. The broken line is the value of the anteroposterior asymmetry index as.

When as is zero, it is symmetrical, which is indicated by a dashed-dotted line. In this calculation example, it can be seen that the critical velocity is improved by introducing an asymmetry in which aS is approximately 1 to 2 m. Figure 8(b)
is the calculation result when normal wheel axles are used for both the front and rear axles. The calculation conditions in FIG. 8 are the calculation results when the trolley runs alone under conditions where the fishing boat is not equipped with pillow springs, lateral movement dampers, yaw damper devices, etc. that improve the stability of the trolley's snaking motion. Therefore, a becomes symmetrical in FIG. 8(b).
In the conventional truck represented by the dot-dash line where s=0, the critical speed of the snake motion is very low. However, the bogie according to claim (3) has a critical speed for meandering motion, even though the conventional bogies cannot be put to practical use and the self-steering performance during curved turns is exactly the same. It is possible to improve stability and ensure stability without any problems in practical use. Note that FIG. 8(b)
It can be seen that the state where aS is not zero is a truck that satisfies only condition (a) of claim (1), and unless condition (b) is satisfied, stability cannot be ensured in this calculation example. In the truck of claim (3), by using independently rotating wheels only on the rear axle, it is possible to improve the critical speed of the meandering action even without a damping force acting element. In addition, in this calculation, for the sake of simplicity, the mass of the bogie frame is ignored, and the other constants are the same as the conditions in FIG. 7.

(Effects of the Invention) As described above, according to the present invention, it is possible to dramatically improve the self-steering performance during curved turns while maintaining the meandering stability of the bogie sufficiently for practical use. Therefore, since the slip acting between the wheels and the rails can be significantly reduced, wear of the wheel treads and the rails 1 22 can be prevented. At the same time, the creep force acting between the wheels and the rails is also reduced, making it possible to significantly reduce the lateral pressure acting on the rails, which helps prevent track destruction. Furthermore, it becomes easier to avoid flange contact, making it possible to prevent wear of flanges and rails and noise caused by flange contact. In other words, it becomes a practically extremely useful trolley.

[Brief explanation of drawings]

FIG. 1 is a plan view of a truck showing an embodiment of claim (1) of the present invention. FIG. 2 is a side view of an improved part of the truck showing claim (2). FIG. 3 is a plan view of a truck showing claim (3). FIG. 4 shows a comparison between the conventional bogie and the bogies according to claims (1) and (3) of the present invention with respect to the behavior of the wheel set when turning around a curve. FIG. 5 is a plan view of a truck showing an embodiment of claim (3). FIG. 6 is a diagram showing the equivalent shear rigidity and equivalent bending rigidity of the wheel shaft support device in the bogie according to claim (3). FIG. 7 shows calculation results showing the effects of claims (1) and (2). FIG. 8 shows calculation results showing the effect of claim (3). l: Bogie frame, 2: Front wheel axle, 3: Rear wheel axle, 4: Axle box, 5:
Left and right direction axle box support rigidity, 6: Front wheel axle longitudinal direction axle box support rigidity, 7: Rear wheel axle longitudinal direction axle box support rigidity, 8: Damping force acting element, 9: Wheel, 10: Axle spring, 11: Damping force Switchable damping force acting element, 12: Independently rotating wheel, 13: Equivalent shear rigidity, 14: Front-rear axle box support rigidity, 15: Equivalent bending rigidity, 16: Link between wheel axle and bogie frame, 17:
Link between wheelsets

Claims (3)

[Claims] (1) A two-axle bogie that satisfies the following two conditions when running. (a) With respect to the traveling direction, the axle box support rigidity of the front axle in the longitudinal direction is smaller than the longitudinal axle box support rigidity of the rear axle. That is, the elastic force acting on the relative yawing displacement between the front wheel axle and the bogie frame is smaller than that of the rear wheel axle. (b) It has a damping force effecting element that acts on the relative yawing speed between the front wheel axle and the bogie frame. (2) A two-axle bogie that satisfies claim (1) and has a damping force acting element that satisfies the following two conditions attached between the axle box and the bogie frame. (b) Generates a damping force against the relative speed of the axle box and bogie frame in the longitudinal direction. (b) The magnitude of the damping force generated can be switched. (3) A two-axle bogie that satisfies the following three conditions in the running state. (a) With respect to the direction of travel, the left and right wheels of the front axle rotate as one, similar to conventional carts. (b) The left and right wheels of the rear axle rotate independently with respect to the direction of travel. (c) Equivalent shear stiffness and equivalent shear damping elements that act on relative lateral displacement and relative lateral speed of the front and rear wheel axles exist at positions offset from the center of the front and rear wheel axles, and A yawing moment is generated between the front and rear wheel axles depending on the left and right speed.