CN115284785A - Tread optimization design method for tramcar wheel - Google Patents

Abstract

The invention provides an optimization design method for the wheel tread of a tram, which can effectively solve the problem of poor adaptability of the original wheel tread of the export tram to match various rail profiles. The profile of the optimized wheel tread rim basically coincides with the original wheel tread, which increases the equivalent taper of the wheel tread and improves the passing ability of the small radius curve of the wheel tread. Optimized from 1 arc and 2 straight lines to 7 arcs and 2 straight lines; the rim width of the optimized wheel tread is 20.8mm, the thickness of the rim is 19.3mm, and the radius of the arc at the throat position of the rim is increased. The bottom height increases the wheel-rail contact area and improves the contact stress at the throat of the wheel flange; the outer end of the wheel tread increases the height in a straight line to avoid too small equivalent taper when it is matched with different rails, and optimizes the wheel tread for different The adaptability of the rail.

Description

A tread optimization design method for tram wheels

technical field

The invention belongs to the technical field of bogies for railway urban rail transit vehicles, and in particular relates to a tread optimization design method for tram wheels.

Background technique

The urban rail transit vehicle railway is road traffic, and its operating speed is relatively low, about 60km/h; the minimum curve radius to pass is relatively small, about 25m. Therefore, the wheel-rail contact relationship of the vehicle, especially the equivalent taper of the wheel tread, has a great influence on the dynamic performance of the vehicle: when the equivalent taper of the wheel tread is too small, the risk of derailment is likely to occur when the vehicle passes a small-radius curve. When the effect cone is too large, the vehicle is prone to instability and poses a threat to driving safety, and also affects the ride comfort of passengers.

The profile stability of the rail and the tread has a great relationship with the distribution of the wheel-rail contact points: when the wheel-rail contact points are concentrated on the rail, the stress distribution is concentrated, which is likely to cause severe local wear, which may cause multiple point contact, conformal contact, etc.

The distribution position of the wheel-rail contact point is closely related to the shape of the wheel tread and the shape of the rail.

At present, the wheel treads used by trams are CB10-type treads (referred to as original wheel treads), and the original wheel treads need to match the four rail profiles of U50, 41GPU, 35GP, and 41GP13 in different sections. The root of the rim of the original wheel tread has a large gradient and the nominal rolling circle of the wheel tread has a too small gradient. When the original tread matches the four rail profiles, there is no wheel-rail contact at the root of the wheel flange. When the wheel moves laterally relative to the rail, the equivalent taper changes from a small value to a large value. At this time, the wheel-rail lateral force also changes to larger value.

When the original wheel tread is matched with four kinds of rails, the slope of the root of the wheel rim is too large and the slope of the outer end of the wheel tread is too small. If the equivalent taper is too small by about 0.025, the risk of derailment is likely to occur when the vehicle passes through a small radius curve; there is no wheel-rail contact relationship at the root of the rim, and when the wheel moves laterally relative to the rail, the equivalent taper changes from a small value to a large value. At this time, the wheel-rail lateral force also changes to a larger value. Therefore, the matching CB10 original wheel tread of the tram has poor adaptability to the four rail profiles.

Therefore, designing a wheel tread shape suitable for different rail profiles has become a valuable key technology for CB10 trams.

Contents of the invention

The object of the present invention is to provide a tramway wheel tread optimization design method, through which treads suitable for four rail profiles of U50, 41GPU, 35GP and 41GP13 can be obtained.

To achieve the above object, the present invention adopts the following technical solutions:

A tread optimization design method for a tramway wheel, comprising the steps of:

(1) Select the U50 steel rail and the original tread, and use the reverse optimization design method of the wheel tread to obtain the reverse design optimized tread profile of the original tread according to the initial contact point of the wheel and rail, the wheel diameter difference and the shape of the rail surface, wherein the original tread It is CB10 type tread;

(2) Match the reverse design optimized tread profiles with 41GPU rails, 35GP rails, and 41GP13 rails, and verify the optimization results according to the equivalent taper and wheel-rail contact relationship. , contact spot size, and contact stress distribution parameters do not meet the optimization target requirements, then return to step (1) to readjust the initial contact point of the rail, wheel diameter difference and other parameters for reverse design optimization; if the matching results meet the optimization target requirements, then obtain the optimized tread profile;

(3) process the optimized tread profile partition that step (2) obtains, divide the vehicle profile into a straight line segment and a curved segment area, and the total number of control segments is less than 10;

(4) Fit the discrete points of each segmented tread profile interval, and calculate the standard deviation σ of the discrete points before and after fitting, and ensure that σ<0.1; if the condition is not met, readjust step (3) Partition in , fit the discrete points in the subsection interval again, and calculate the standard deviation until σ satisfies the condition;

(5) Smoothly connect and fit all straight line segments and curve segment areas that meet the conditions to obtain the final optimized fitting design tread;

The thickness of the final optimized fitting design tread is 19.3mm, and the equivalent taper is 0.15; it includes sequentially connected wheel rim, throat root area, work area, low cone area and chamfer area, and the width of the wheel rim is 20.8mm, from the throat area to the low cone area, including the first circular arc, the second circular arc, the third circular arc, the fourth circular arc, the fifth circular arc, the sixth circular arc, the first straight line, the Seven arcs and the second straight line, the radius of the first arc is 12mm, the radius of the second arc is 26mm, the radius of the third arc is 60mm, the radius of the fourth arc is 300mm, the radius of the fifth arc is is 200mm, the radius of the sixth arc is 30mm, the slope of the first line is 1:40 and its horizontal projection length is 15mm, the radius of the seventh arc is 50mm, and the slope of the second line is 1:20 And its horizontal projection length is 42mm.

Advantage and positive effect of the present invention compared with prior art are as follows:

(1) The shape of the common working area (-6mm ~ 6mm) of the optimized wheel tread basically coincides with the original tread to ensure that the optimized wheel tread does not affect the normal operation performance of the tram.

(2) Optimize the wheel tread, increase the equivalent taper to 0.15, and change the profile from the original wheel tread flange throat area to the outer end of the tread from 1 arc and 2 straight lines to 7 arcs and 2 straight lines, Improve the ability of the wheel tread to pass through small curves.

(3) The rim thickness of the optimized wheel tread is increased by 0.06mm compared with the rim width of the original wheel tread, the slope at the root of the rim is reduced, and the radius of the arc and the height of the bottom are increased, thereby increasing the wheel-rail contact area and improving The adaptability of the wheel tread to the rail, and at the same time, alleviate the excessive force of the wheel-rail contact.

(4) Optimize the design of the transition area of the tread: increase the height of the straight line DC and CB at the outer end of the wheel tread, and shorten the length of the slope of the straight line DC at the outer end to 1:40. The slope of the straight line CB is 1:20 to avoid It produces an equivalent taper that is too small when the area matches the rail.

Description of drawings

Fig. 1 is a schematic diagram of the design method for optimizing the tread of a wheel according to the present invention.

Fig. 2 is a schematic diagram showing the comparison between the optimized wheel tread of the present invention and the original tread.

Figure 3 is a comparative schematic diagram of four kinds of rails.

Fig. 4 Schematic diagram of the wheel-rail contact relationship when the original wheel tread is matched with the U50 rail.

Figure 5 is a schematic diagram of the wheel-rail contact relationship when the wheel tread is matched with the U50 rail.

Figure 6. Schematic diagram of the wheel-rail contact relationship when the original wheel tread is matched with the 41GPU rail.

Figure 7 is a schematic diagram of the wheel-rail contact relationship when the wheel tread is matched with the 41GPU rail.

Figure 8 is a schematic diagram of the wheel-rail contact relationship when the original wheel tread is matched with the 35GP rail.

Figure 9 is a schematic diagram of the wheel-rail contact relationship when the wheel tread is matched with the 35GP rail.

Figure 10 is a schematic diagram of the wheel-rail contact relationship when the original wheel tread matches the 41GP13 rail.

Figure 11 is a schematic diagram of the wheel-rail contact relationship when the optimized wheel tread matches the 41GP13 rail.

Figure 12 Schematic diagram of the equivalent taper when the original wheel tread matches the four rail profiles.

Fig. 13 Schematic diagram of the equivalent taper when the optimized wheel tread matches the four rail profiles.

Fig. 14 Schematic diagram of the contact stress when the original wheel tread matches the four rail profiles.

Fig. 15 is a schematic diagram of the contact stress when the optimized wheel tread matches the four rail profiles.

Detailed ways

A kind of tramway wheel tread optimization design method that the present embodiment provides, comprises the following steps:

(1) Select the U50 steel rail and the original tread, and use the reverse optimization design method of the wheel tread to obtain the reverse design optimized tread profile of the original tread according to the initial contact point of the wheel and rail, the wheel diameter difference and the shape of the rail surface, wherein the original tread It is CB10 type tread;

(2) Match the reverse design optimized tread profiles with 41GPU rails, 35GP rails, and 41GP13 rails, and verify the optimization results according to the equivalent taper and wheel-rail contact relationship. , contact spot size, and contact stress distribution parameters do not meet the optimization target requirements, then return to step (1) to readjust the initial contact point of the rail, wheel diameter difference and other parameters for reverse design optimization; if the matching results meet the optimization target requirements, then obtain the optimized Tread profile; the optimization target requirement means that the equivalent taper is 0.15, and the wheel-rail contact relationship, contact spot size, and contact stress are all better than the original tread surface. The contact stress is more uniform;

(3) process the optimized tread profile partition that step (2) obtains, divide the vehicle profile into a straight line segment and a curved segment area, and the total number of control segments is less than 10;

(4) Fit the discrete points of each segmented tread profile interval, and calculate the standard deviation σ of the discrete points before and after fitting, and ensure that σ<0.1; if the condition is not met, readjust step (3) Partition in , fit the discrete points in the subsection interval again, and calculate the standard deviation until σ satisfies the condition;

(5) Smoothly connect and fit all straight line segments and curve segment areas that meet the conditions to obtain the final optimized fitting design tread;

As shown in FIG. 1 , the thickness of the final optimized fitting design tread is 19.3 mm, and the equivalent taper is 0.15. It includes sequentially connected rim, throat area, working area, low cone area and chamfering area, the width d9 of the rim is 20.8mm, and it includes sequentially connected arc QP with radius R10 and straight line segment PM , the arc ML with a radius of R9, the straight line segment LK, the arc KJ and the straight line segment JI with a radius of R8, the rim of the present embodiment and the rim of the original tread, only the rim width d9 of the optimized wheel tread is 20.8mm , the thickness of the rim is determined to be 19.3mm, R8=R9=4mm, R10=10mm, α=70°, β=75°. Throat area to low cone area includes the first circular arc IH with radius R7, the second circular arc HG with radius R6, the third circular arc GF with radius R5, and the fourth circular arc FE with radius R4 connected in sequence , the fifth arc EO whose radius is R3, the sixth arc OD whose radius is R2, the first straight line DC, the seventh arc and the second straight line CB whose radius is R1, R1=50mm, R2=30mm, R3 =300mm, R4=200mm, R5=60mm, R6=26mm, R7=12mm, the slope of the first straight line DC is 1:40 and the length of its horizontal projection d4 is 15mm, the radius of the seventh arc is 50mm, the first The slope of the two straight lines CB is 1:20 and the length of its horizontal projection d3 is 42mm, and the horizontal projection length d5 of the arc DE is 21mm. The chamfering area includes a straight line BA, and the lengths d1 and d2 of the horizontal projection and the vertical projection of the straight line BA are both 3mm.

Table 1 Comparison of key parameters between the optimized wheel tread and the original wheel tread

wheel tread Rim width d9 Height of outer end of tread OB Rim root radius R5\R6\R7 Tread profile R3/R4/L1 original tread 20.74 2.79 13 1:40 Optimized tread 20.8 2.54 60\26\12 200/300/1:40

The tread surface optimized in this embodiment and the original tread surface are analyzed respectively with U50 rail, 41GPU rail, 35GP rail, and 41GP13 rail contact relationship, as shown in Figures 4 to 11, as can be seen from the figure, the optimized tread surface of this embodiment can not only adapt to It is equipped with U50 rail, 41GPU rail, 35GP rail, 41GP13 rail, and its contact relationship is far better than the original tread.

Then measure and map the equivalent taper and contact stress respectively, and the results are shown in Fig. 12-15. In this embodiment, the wheel tread is optimized, the equivalent taper is increased to 0.15, and the profile from the original wheel tread rim throat area to the outer end of the tread is changed from 1 arc and 2 straight lines to 7 arcs and 2 straight lines. Improve the ability of the wheel tread to pass through small curves.

The thickness of the rim of the optimized wheel tread in this embodiment is 0.06mm larger than the width of the rim of the original wheel tread, the slope at the root of the rim is reduced, the radius of the arc and the height of the bottom are increased, thereby increasing the wheel-rail contact area, Improve the adaptability of the wheel tread to the rail, and at the same time alleviate the excessive force of the wheel-rail contact.

The optimized design of the tread transition area in this embodiment: the height of the straight line DC and CB at the outer end of the wheel tread is increased, the slope of the straight line segment DC at the outer end is 1:40, and its length is shortened, and the slope of the straight line segment CB is 1:20, Avoid that it produces too little equivalent taper when the area matches the rail.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, and any transformation and replacement based on the technical solutions and inventive concepts provided by the present invention should be covered by the scope of protection of the present invention Inside.

Claims (1)

1. a tread optimization design method of tramcar wheel, it is characterized in that comprising the steps: (1) Select the U50 steel rail and the original tread, and use the reverse optimization design method of the wheel tread to obtain the reverse design optimized tread profile of the original tread according to the initial contact point of the wheel and rail, the wheel diameter difference and the shape of the rail surface, wherein the original tread It is CB10 type tread; (2) Match the reverse design optimized tread profiles with 41GPU rails, 35GP rails, and 41GP13 rails, and verify the optimization results according to the equivalent taper and wheel-rail contact relationship. , contact spot size, and contact stress distribution parameters do not meet the optimization target requirements, then return to step (1) to readjust the initial contact point of the rail, wheel diameter difference and other parameters for reverse design optimization; if the matching results meet the optimization target requirements, then obtain the optimized tread profile; (3) process the optimized tread profile partition that step (2) obtains, divide the vehicle profile into a straight line segment and a curved segment area, and the total number of control segments is less than 10; (4) Fit the discrete points of each segmented tread profile interval, and calculate the standard deviation σ of the discrete points before and after fitting, and ensure that σ<0.1; if the condition is not met, readjust step (3) Partition in , fit the discrete points in the subsection interval again, and calculate the standard deviation until σ satisfies the condition; (5) Smoothly connect and fit all straight line segments and curve segment areas that meet the conditions to obtain the final optimized fitting design tread; The thickness of the final optimized fitting design tread is 19.3mm, and the equivalent taper is 0.15; it includes sequentially connected wheel rim, throat root area, work area, low cone area and chamfer area, and the width of the wheel rim is 20.8mm, from the throat area to the low cone area, including the first circular arc, the second circular arc, the third circular arc, the fourth circular arc, the fifth circular arc, the sixth circular arc, the first straight line, the Seven arcs and the second straight line, the radius of the first arc is 12mm, the radius of the second arc is 26mm, the radius of the third arc is 60mm, the radius of the fourth arc is 300mm, the radius of the fifth arc is is 200mm, the radius of the sixth arc is 30mm, the slope of the first line is 1:40 and its horizontal projection length is 15mm, the radius of the seventh arc is 50mm, and the slope of the second line is 1:20 And its horizontal projection length is 42mm.

Images