JP2006275230A - Brake lining and disc brake for railroad vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce local contact bearing pressure, by securing the contact area between a brake lining and a brake disc in braking. <P>SOLUTION: This brake lining 1 is pressed from both sides to both side surfaces of a railroad vehicle wheel or a sliding surface of the brake disc installed on a axle, and is composed of a frictional member 2 for contacting with the brake disc 15 and a back board 3 for installing this frictional member 2. The frictional member 2 is divided into a plurality, and the divided respective frictional members 2 can rotate in the substantially radial direction of at least the brake disc 15 to the back board 3, and a position for applying pressing force to the respective frictional members 2 exists in an area of an inscribed circle having a diameter of 0.27 to 0.67 of a diameter of a concentric circle with a circle inscribed in the respective frictional members 2. The contact area between the brake lining and the brake disc in braking can be sufficiently secured, and an increase in the local contact bearing pressure can be reduced, and an excessive temperature rise can be restrained, and abrasion resistance can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention mainly secures a contact area between a sliding surface of a brake disk and a friction member of a brake lining even in a state where the brake disk is deformed by a braking load, mainly for a disk brake for a railway vehicle. Thus, the present invention relates to a brake lining and a disc brake that can suppress an increase in temperature during a braking load of the brake disc and the brake lining and can improve the wear resistance of the brake disc and the brake lining.

  Block brakes, drum brakes, disk brakes, and the like are used as braking devices for land transportation machines such as railway vehicles, automobiles, and motorcycles. In recent years, disk brakes have been frequently used with the increase in speed and size of vehicles.

  A disc brake is a device that obtains a braking force by friction between a brake disc and a brake lining. Usually, a brake caliper presses the brake lining against the sliding surface of a brake disc attached to an axle or a wheel with bolts. A braking force is obtained and the speed of the vehicle is controlled by braking the rotation of the axle or wheels.

  4A and 4B show the shape of a conventional brake lining for a railway vehicle. FIG. 4A is a radial-circumferential plan view of the brake lining, and FIG. 4B is a radial-axial cross-sectional view showing a cross section. As shown in FIGS. 1A and 1B, a conventional brake lining 11 is configured by attaching a friction member 12 that contacts a brake disc to a back plate 13. For attachment, a rivet 14 or the like is applied, and the friction member 12 and the back plate 13 are fixed relatively firmly.

  FIG. 5 is a radial-axial sectional view schematically showing the contact state between the brake disc 15 and the brake lining 11 during braking in a conventional railway vehicle disc brake. As shown in the figure, when braking is applied from a high speed state to the brake disk 15, the temperature in the vicinity of the sliding surface 15a rises and deforms into a convex shape.

  When the brake disc is deformed in this way, the brake lining and the brake disc come into contact only in the vicinity of the apex of the convex portion, the contact area decreases, and the contact surface pressure increases locally.

  When the contact area decreases and the contact surface pressure locally increases, braking energy is input to a small area, resulting in an excessive temperature rise of the brake lining and brake disc during braking. Further, since the wear of the brake lining and the brake disc occurs in the contact area between them, the reduction of the contact area may shorten the life due to wear.

  Therefore, especially in high-speed vehicles such as the Shinkansen, a sufficient contact area during braking of the brake lining and the brake disc is secured to reduce local contact surface pressure from the viewpoint of suppressing temperature rise and improving wear resistance. This is very important.

Patent Document 1 discloses a brake lining for a partial lining-disc brake provided with a large number of friction members as a technique for uniformly bringing a brake lining and a brake disk into contact with each other.
Japanese National Patent Publication No. 10-507250

  The brake lining disclosed in Patent Document 1 has features such that a large number of friction members are provided on the brake lining, and that each friction member can be turned by a spherical seat. Moreover, it has a structure in which the pressing load from the brake caliper is equally applied to each friction member.

  With these features, in the disc brake having the brake lining disclosed in Patent Document 1, it is possible to make the brake lining and the brake disc contact evenly as compared with the disc brake having the conventional brake lining. Yes.

  Further, in the brake lining disclosed in Patent Document 1, when attention is paid to the contact surface pressure of one friction member, even if a circumferential tangential force generated by rotation of the brake disk acts due to the effect of the spherical seat, the brake lining is applied. Since the resultant force of the caliper pressing force and tangential force always acts on the center of each friction member, the contact surface pressure received from the brake disk acts uniformly on the surface of each friction member, and the contact surface pressure locally increases. It can be suppressed.

  However, in reality, the friction member is a deformed body, so that a minute deformation occurs on the contact surface with the brake disk. Due to such deformation, when the resultant force of the pressing force and the tangential force acts on the center of the friction member as in the brake lining disclosed in Patent Document 1, as shown in FIG. The contact surface pressure does not act uniformly on the surface of the friction member, and the contact surface pressure locally increases at a specific portion. Further, the same tendency occurs when the load position on the friction member is too close to the center.

  In addition, the brake lining as described above has a more complicated structure than the conventional brake lining, and therefore the number of parts increases. As a result, weight and cost increase.

  The problem to be solved by the present invention is that conventional brake linings and brake discs for railway vehicles have a simple configuration, and ensure a sufficient contact area between the brake lining and the brake discs during braking and provide local contact. The surface pressure cannot be reduced.

  An object of the present invention is to reduce the contact area between the brake lining and the brake disc during braking in order to suppress an excessive temperature rise of the brake lining and the brake disc or to improve wear resistance in the disc brake for a railway vehicle. It is in the point which increases and suppresses that a contact surface pressure increases locally.

In response to the above problems, the present inventors have studied the structure of a disc brake by finite element analysis, and have established the present invention as follows.
That is, the brake lining of the railway vehicle disc brake of the present invention is:
To ensure the contact area between the brake lining and brake disc during braking,
In the brake lining that is attached to the brake caliper and pressed from both sides to the both sides of the railway wheel or the sliding surface of the brake disc attached to the axle,
A friction member in contact with the brake disc;
It consists of a back plate for attaching this friction member,
The friction member is divided into a plurality of parts, and each of the divided friction members is rotatable at least in a substantially radial direction of the brake disc with respect to the back plate.

In addition, the brake lining of the railway vehicle disc brake of the present invention is:
In order to prevent the load from concentrating on a specific part and locally increasing the contact pressure even if a tangential force due to the rotation of the brake disc acts,
The position where the pressing force is applied to each friction member is concentric with the circle inscribed in each friction member, and the diameter is in the region of 0.27 to 0.67 times the diameter of the inscribed circle. Yes.

Moreover, in the brake lining of the railway vehicle disc brake of the present invention,
If a member having a spring mechanism is inserted between each of the plurality of divided friction members and the back plate, each friction member rotates not only in the radial direction with respect to the back plate but also in other directions. In addition, displacement in the plate thickness direction is also possible, and the contact area between the brake lining and the brake disc during braking can be further increased. In this case, it is desirable to use a relatively space-saving disc spring as the member having the spring mechanism.

Moreover, in the brake lining of the railway vehicle disc brake of the present invention,
Load member with said spring mechanism - the slope of the displacement relationship, that is, the spring constant, the average value _{k mean,} when the number of friction members is n, such as _{n · k mean} is 40~180kN / mm If the value is set, even if the brake disk is deformed, the pressing force from the brake caliper is applied to each friction member as evenly as possible.

Further, in a high-speed vehicle such as the Shinkansen, the value of n · k _mean (40 to 180 kN / mm) is at least within a range from room temperature to 400 ° C. because the temperature becomes relatively high due to friction during braking. It is desirable.

  In general, the lower limit value is set so that the yield stress of the spring member material inserted between each friction member and the back plate can always function as a spring (can be elastically deformed) during use (this can be elastically deformed). When the yield stress depends on the shape and number of springs). However, since the high-speed vehicle is in a high-temperature environment as described above, the yield stress of the material used should be at least 0.9 times the yield stress at room temperature in the range of room temperature to 400 ° C. Is desirable.

Moreover, the disc brake for railway vehicles of the present invention comprises:
The main feature is to have the brake lining according to any one of the above-described present invention.

  In the present invention, a sufficient contact area between the brake lining and the brake disk during braking can be secured, and an increase in local contact surface pressure can be reduced, so that an excessive temperature rise can be suppressed and wear resistance can be improved. Is possible.

The best mode for carrying out the present invention will be described below with reference to FIG.
1A and 1B show an embodiment of the present invention, in which FIG. 1A is a radial-circumferential plan view of a brake lining for a railway vehicle, FIG. 1B is a cross-sectional view taken along line AA in FIG. BB sectional drawing of (a), (d) shows the positional relationship of a spring member about one friction member.

  As shown in FIG. 1, in the brake lining 1 of the present invention, for example, the friction member 2 is divided into twelve pieces, and the inner diameter is 20 mm and the outer diameter is between these friction members 2 and the back plate 3. The same disc spring 4 having 40 mm and a spring constant of 6 kN / mm is inserted so that the inner diameter side is in contact with the friction member 2.

  By adopting such a configuration, even if the brake disc is deformed during braking, the disc spring 4 is elastically deformed, and each friction member 2 rotates relative to the back plate 3 and rotates. Since displacement in the direction is possible, a sufficient contact area between the brake lining 1 and the brake disc can be secured.

  In the example of FIG. 1, the friction member 2 and the disc spring 4 are in contact with each other on a circle having a diameter of 20 mm (on the inner diameter of the disc spring 4), and the pressing force from the brake caliper is applied to this portion. This is a concentric circle having a diameter of 0.4 times with respect to a circle having a diameter of 50 mm inscribed in the friction member 2, so that even if a tangential force due to the rotation of the brake disk is applied, the contact surface pressure is locally increased. Can be prevented from becoming high.

  Thus, in order to suppress local increase in contact surface pressure during braking, the pressing force is applied to the friction member 2 according to the finite element analysis of the inventors. A region indicated by hatching in d) is a concentric circle having a diameter not less than 0.27 times and not more than 0.67 times the inscribed circle of the friction member 2 (circle having a diameter of 50 mm in the example of FIG. 1). It is necessary to be within. More preferably, the diameter is within a range of 0.33 times or more and 0.58 times or less of a concentric circle.

  In such a range, the force received by the friction member 2 is not too close to the center or the end, so as shown in FIG. It is possible to suppress local contact with some parts. As a result, it is possible to suppress a local increase in contact surface pressure.

  If the load on each friction member 2 is on a concentric circle having a diameter smaller than 0.27 times the circle inscribed in the friction member 2, the load is too concentrated at the center of the friction member 2. The surface is deformed, and the surface pressure locally increases near the center of the friction member 2. On the other hand, when the load on each friction member 2 is on a concentric circle having a diameter larger than 0.67 times the circle inscribed in the friction member 2, the load is on the outer peripheral side of the friction member 2 as shown in FIG. This is because the contact surface of the friction member 2 is tilted by the tangential force because it gathers at the end, and the surface pressure locally increases on the side that contacts the brake disk 15 first.

In the example of FIG. 1, since the spring constant of the disc spring 4 is 6 kN / mm, the average spring constant k _mean of these disc springs 4 and the multiplier n · k _mean of the number n of the friction members 2 are 72 kN / mm. Therefore, even if the brake disc is deformed, the pressing force from the brake caliper is applied to each friction member 2 relatively evenly, and it is possible to suppress a decrease in contact area and an increase in contact surface pressure.

The n · k _mean is preferably 40 kN / mm or more and 180 kN / mm or less, more preferably 60 kN / mm or more and 120 kN / mm or less, according to the inventors' finite element analysis. When n · k _mean is less than 40 kN / mm, the disc spring 4 is crushed when the pressing force is applied, the load on a specific friction member 2 increases, and the pressing force is evenly applied. May not be possible. On the other hand, if n · k _mean is larger than 180 kN / mm, the disc spring 4 cannot be sufficiently deformed, and the pressing force is not equally applied to the friction members 2.

In order to give a more uniform pressing force to each friction member 2, the force received by each friction member by adjusting the spring constant of each disc spring within an n · k _mean range of 40 to 180 kN / mm. Is preferably constant.

  The member having the spring mechanism used in the present invention is not limited to the disc spring 4 as shown in FIG. 1, but may be a square spring, bamboo shoot spring, coil spring, or the like. However, the disc spring has an advantage that a large load can be borne in a small space compared to a square spring or the like.

By the way, when the brake lining 1 having the configuration shown in FIG. 1 is applied to a high-speed vehicle such as a Shinkansen, it is preferable that the characteristics of the spring member to be used do not change even at a certain high temperature because the environment becomes high temperature during braking. Therefore, the spring constant is preferably in the range of at least normal temperature to 400 ° C. and n · k _mean of 40 to 180 kN / mm, more preferably 500 ° C. is satisfied.

  In general, the yield stress of the material used for the spring member is designed so that the spring can be elastically deformed at all times during use. However, when it is in a high temperature environment, the yield stress should be at least in the range from room temperature to 400 ° C. The stress is preferably at least 0.9 times the yield stress at room temperature. More preferably, the yield stress is 0.95 times or more of the yield stress at room temperature in the range from room temperature to 500 ° C.

  In order to prevent the spring characteristics from changing even in such a high temperature environment, for example, when hot working tool steel is used as a material for the spring, the spring constant at 400 ° C. is 0.88 times the normal temperature. The yield stress is 0.95 times, and the effect is sufficiently exhibited.

  By the way, the position 5 for applying the pressing load from the brake caliper to the brake lining passes through the center of gravity 1G of the brake lining 1 as shown in FIG. 1A, and the longitudinal direction of the brake lining 1 (FIG. 1A). On the straight line parallel to the horizontal direction of the paper.

  Thereby, the said pressing load is given to each friction member 2 comparatively equally, and there exists an effect which increases a contact area more.

  In FIG. 1, the friction member 2 is divided into 12 pieces. However, in order to exert the effect, the friction member 2 may be divided into 6 pieces or more. Further, the brake lining 1 is arranged in two rows in the inner and outer peripheral directions perpendicular to the longitudinal direction except for both end portions 1a and 1b in the longitudinal direction.

  Two or more rows of friction members 2 are preferably arranged in the inner and outer circumferential directions as shown in FIG. As described above with reference to FIG. 5, during braking, the brake disc is deformed into a convex shape in the radial direction. This is because the contact area can be further increased. This is because if only one row is arranged, contact is made only at one of the inner peripheral side, the outer peripheral side, and the center of the friction member 2, and the contact area may be reduced.

  In the present invention, the number of friction members 2 attached to the longitudinal ends 1a and 1b of the brake lining 1 is not defined. This is because it is related to the constraints on the shape of the brake caliper when it is mounted, and there are many cases where sufficient space cannot be secured at both ends 1a and 1b in the longitudinal direction. In particular, since it is difficult to dispose two or more rows of friction members 2 in the inner and outer circumferential directions, it is not defined in the present invention. Accordingly, it is needless to say that it is preferable to arrange a sufficient number of friction members 2 at both end portions 1a and 1b if a space can be secured.

The structure shown in FIG. 1 is relatively simple, has a small number of parts, and is advantageous in terms of weight and cost.
The material used for the friction member 2 is preferably a commonly used sintered material or resin material.

  In order to investigate the structure of brake lining and brake caliper that can suppress excessive temperature rise of brake lining and brake disc and improve wear resistance, finite element analysis was conducted for disc brakes for railway vehicles. The results will be described.

  The finite element analysis was performed under conditions corresponding to emergency braking from a traveling speed of 360 km / h. The target disc brake is a Shinkansen disc brake, and the brake lining dimensions including the back plate are 400 mm in length (approximately in the circumferential direction of the brake disc) and 140 mm in width (approximately in the radial direction of the brake disc). . The friction member was divided into 12 pieces.

  The maximum contact area between the brake lining and the brake disc is 130 mm in the radial direction and 80 ° of the brake disc in the circumferential direction. The friction member used was a copper-tin-graphite sintered material that is currently used for Shinkansen brake linings.

  The brake disc is also a forged steel brake disc for the Shinkansen, and is attached to the wheel side surface by bolts.

Table 1 below summarizes the brake linings studied and the disc brakes equipped with this brake lining.
The structure shown in Table 1 shows the structure between the friction member and the back plate in the brake lining, and the structure in which various springs are inserted is evaluated. Further, in the comparative example, as in the conventional case, the friction member and the back plate are firmly connected with rivets.

The explanation about each item of Table 1 is shown below.
The structure represents the type of spring when a spring is inserted, and the coupling method between the friction member and the back plate for the others. The contact area represents a contact area between the friction member and the spring member, that is, a position where a pressing load from the brake caliper is applied, and represents a ratio to a diameter of a circle inscribed in the friction member.

The spring constant is a multiplier of the average spring constant k _mean ²⁰ at normal temperature of the spring member to be inserted and the number n of friction members, and a multiplier of the average spring constant k _mean ⁴⁰⁰ at 400 ° C. and the number n of friction members. Respectively. Although not shown in Table 1, all of the examined spring members have the same spring constant.

σ _Y ⁴⁰⁰ / σ _Y ²⁰ represents the ratio of the yield stress at 400 ° C. to the normal yield stress of the spring member. The pressing position represents a load position (pressing position) from the brake caliper to the back plate, and is on a straight line that passes through the center of gravity of the brake lining and is substantially parallel to the longitudinal direction of the brake lining.

  Table 2 below shows the ratio between the maximum value and the average value of the contact surface pressure between the brake disk and the brake lining during braking obtained by finite element analysis. That is, it is shown that there is a portion where the contact surface pressure is locally higher as this value is larger, and there is a possibility that the temperature rises during braking and the amount of wear increases. Here, the average value of the contact surface pressure is an ideal contact surface pressure obtained by dividing the pressing load by the total contact area of the friction member.

  As shown in Table 2, compared to conventional comparative examples 1 and 2 in which each friction member cannot move independently, and comparative examples 3 and 4 in which the contact area between the friction member and the spring member is not within an appropriate range. In all of the embodiments of the present invention, the ratio between the maximum value and the average value of the contact surface pressure is small, the local contact surface pressure is reduced, and the excessive temperature rise of the brake disc and the brake lining is suppressed. It can be seen that the wear resistance can be improved.

  The present invention is not limited to the above example, and it goes without saying that the embodiment may be appropriately changed within the scope of the technical idea described in each claim.

  For example, a sintered material other than copper-tin-graphite or a resin material can be used for the friction member. In addition to the forged steel brake disc, the brake disc can be applied to a cast iron brake disc and an aluminum composite brake disc.

  The present invention described above can be applied not only to railway vehicles but also to automobiles, motorcycles and the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the brake lining of this invention which has a spring structure which is one Embodiment of the disc brake for railway vehicles of this invention, (a) is radial direction-circumferential direction top view, (b) is A- of (a). A sectional view, (c) is a sectional view taken along the line BB of (a), and (d) is a diagram showing the positional relationship of the spring member with respect to one friction member. Sectional drawing explaining the case where a load position is appropriate in the brake lining of this invention shown in FIG. Sectional drawing explaining the case where a load position exceeds an appropriate range in the brake lining of this invention shown in FIG. It is a figure which shows the brake lining of the conventional disc brake for rail vehicles, (a) is radial direction-circumferential direction top view, (b) is AA sectional drawing of (a). It is a schematic diagram which shows the contact state of the brake disc and the conventional brake lining during a brake. Sectional drawing explaining the contact part with the brake disc in the brake lining disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brake lining 1a, 1b Both ends of a longitudinal direction 1G Center of gravity 2 Friction member 3 Back plate 4 Disc spring 5 Pressing load application position 15 Brake disc

Claims (7)

In the brake lining that is attached to the brake caliper and pressed from both sides to the both sides of the railway wheel or the sliding surface of the brake disc attached to the axle,
A friction member in contact with the brake disc;
It consists of a back plate for attaching this friction member,
The friction member is divided into a plurality of parts, and each of the divided friction members can rotate at least in a substantially radial direction of the brake disk with respect to the back plate, and a pressing force is applied to each friction member. A brake lining of a disk brake for a railway vehicle, wherein the position is concentric with a circle inscribed in each friction member and a diameter is in a region of 0.27 to 0.67 of a diameter of the inscribed circle.   The brake lining for a disk brake for a railway vehicle according to claim 1, wherein a member having a spring mechanism is inserted between each friction member and the back plate.   The brake lining of a disk brake for a railway vehicle according to claim 2, wherein the member having the spring mechanism is a disc spring. The spring constant of the member having the spring mechanism is
When the average value of _{k mean} the spring constant of the member with all of the spring mechanism to be used, the number of friction members is n, and wherein the _{n · k mean} is a value such that 40~180kN / mm The brake lining of the disk brake for railway vehicles according to claim 2 or 3. The brake lining of a disk brake for a railway vehicle according to claim 4, wherein the value of n · k _mean (40 to 180 kN / mm) is at least a value in a range from room temperature to 400 ° C.   The railway vehicle according to any one of claims 2 to 5, wherein a yield stress of the member having the spring mechanism is 0.9 times or more of a yield stress at room temperature at least in a range from room temperature to 400 ° C. Brake lining for disc brakes. In railway vehicle disc brakes that obtain braking force by pressing the brake lining attached to the brake caliper from both sides to the sliding surface of the brake disc attached to both sides of the wheel or axle,
A disc brake for a railway vehicle, comprising the brake lining according to any one of claims 1 to 6.

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