JP2002291201A - Slide contact structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce electric resistance in mutual connection without increasing the mechanical friction in mechanical sliding between members such as a blush and a slip ring of an electric motor. SOLUTION: A slide contact surface a4 at the end surface of a cylindrical sintered body a3 as a slide contact A slidably contacts the slide contact receiving surface b3 of a copper disc b2 rotating relatively. On the outer jacket a1 of the sintered body a3, the density of conductive member is higher than that of a core a2. In the core a2 of the sintered body a3, the density of a solid lubricant is higher than that of the outer jacket a1. Because the current between the slide contact surface a4 and the slide contact receiving surface b3 concentrates on the outer jacket a1, mutual electric resistance is reduced. The decrease of the friction factor by a solid lubricat is not lost at a core portion a2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention typically relates to a mechanical inter-sliding function between two members that move relative to each other, as seen in the example of a brush and a slip ring in an electric motor. Contact structure for simultaneously ensuring both of the functional interconnect functions, and in particular, the quality of the electrical interconnect function of both functions of such a sliding contact structure. The present invention relates to an improvement in gradually decreasing electric resistance at a dominant sliding contact surface.

[0002]

2. Description of the Related Art Conventional structures of this type include copper and copper.
Metal particles such as nickel alloy (Cu-Ni), tin (Sn) and titanium (Ti) are mixed with a conductive agent composition, boron nitride (BN), graphite, tungsten disulfide (W
S ₂ ), a columnar sliding contact body formed of a sintered body in which the composition of a solid lubricant containing material particles such as mica (Si, Al, K) is uniformly distributed throughout, for example, It is frequently used as a sliding contact member for a brush of an electric motor, and a sliding contact surface is formed on one end surface of such a columnar sintered body, and for this sliding contact surface, for example, A conductive sliding contact member such as a copper ring which is frequently used for a slip ring of an electric motor or a metal flat plate which is frequently used as a sliding contact member of other industrial machines is slidably slidable relative to each other. A sliding contact structure configured as described above is known.

[0003]

However, in such a conventional sliding contact structure, the contact resistance that governs the electrical interconnection function, that is, the electrical resistance at the sliding contact surface is: It is extremely high compared to the contact resistance between metals, for example, 8.5 mm under the adoption of a sliding contact member made of copper.
Usually, for example, a value of about 18 mΩ is exhibited with respect to a circular sliding contact surface of φ. On the sliding contact surface formed on the sintered body as a sliding contact body of this kind of sliding contact structure, the composition of the conductive agent and the composition of the solid lubricant are in the form of particles or particles of the order of 100 microns. Exposed in the form of a uniform distribution of lumps, thereby providing an electrical interconnection function in the form of a diminution of electrical resistance at the sliding contact surface caused by particles or particulate lumps of conductive agent. The enhancement is achieved at the expense of an enhanced mechanical inter-sliding contact function in the form of a gradual decrease in the coefficient of friction at the sliding contact surface, which is provided by particles or a particulate mass of solid lubricant. Thus, there is a harmonization of the demands of the trade-offs of diminishing electrical resistance and diminishing friction coefficient. Therefore, it can be said that there is an inherent tendency to exhibit a high resistance relative to the electrical resistance at the sliding contact surface between the metals.

In addition, the electric resistance at the sliding contact surface is further dependent on the interdependent action of the current flowing intensively on the particles or granular lumps of the conductive agent composition uniformly distributed on the sliding contact surface. The mechanism of the resulting mutual resistance is described in Greenwood's theory (Source: JA Greenwood, “Constric”
Tension resistance and ther
eal area of contact ", Brit.
J. Appl. Phys. , Vol. 17, pp. 16
21-1632, 1966), the inventor of the present application has enthusiastically continued empirical research on the application of this theory to the mechanism of generation of electrical resistance at the sliding contact surface of a sintered body. As a result, the conductive agent particles or granular mass uniformly distributed in the central region on the sliding contact surface,
The overall interaction from the current concentrated point-wise on the conductive agent particles, etc. across the sliding contact surface creates a relatively large mutual resistance, which creates a large electrical resistance on the sliding contact surface. While the resistance is substantially dominant, the conductive agent particles uniformly distributed in the peripheral region on the sliding contact surface are exclusively concentrated in the peripheral region in the peripheral region. Since the interaction from the current generated only generates a relatively small mutual resistance, it is demonstrated that the current on the sliding contact surface concentrates on the conductive agent particles and the like in these peripheral areas. (Source: Y. Watanabe, Ana)
lysis of Contact Resistan
ce in Composite Materials
forSliding Contacts, IEIC
E Trans, Electron. Japan vo
l. E83-C No. 9. pp. 1409-1413
September 2000). According to the empirical elucidation of the present inventor, the mutual resistance of the green wood generated on the sliding contact surface of the sintered body is caused by the mixture of the particles of the solid lubricant or the lump on the particles for decreasing the friction coefficient there. Momentum, since it is the resistance of the excess element exceeding the resistance of the compensation
Even if the coefficient of friction gradually decreases, the electrical resistance generated on the entire sliding contact surface becomes large, and from that surface, there is a problem that the range of use of the conventional sliding contact structure is restricted. Was.

[0005] Therefore, by suppressing the electric resistance due to the mutual resistance of the excess elements to a minimum, without sacrificing the effect of decreasing the friction coefficient due to the mixture of the particles or granular lumps of the solid lubricant. SUMMARY OF THE INVENTION It is an object of the present invention to provide a sliding contact structure in which the overall electric resistance on the sliding contact surface of a sintered body is greatly reduced.

[0006]

In view of the problem that the range of application is limited by a large electric resistance on the sliding contact surface of the conventional structure, the inventions according to claims 1 to 3 have the following problems.
In the peripheral area on the sliding contact surface where the occurrence of mutual resistance is small, the composition of the conductive agent is distributed at a high density, and from the opposite viewpoint,
The above problem is solved by distributing the composition of the solid lubricant at a high density in the central region on the sliding contact surface where the occurrence of mutual resistance is remarkable. It is an object of the present invention to provide an excellent sliding contact structure in which the overall electric resistance is greatly reduced without sacrificing the effect of decreasing the coefficient of friction.

[0007]

According to the first aspect of the present invention, the sliding contact body is formed of a sintered body having a composition of a conductive agent and a composition of a solid lubricant, and a sliding contact surface is formed on one surface of the cube. A sliding contact receiving surface, wherein the conductive sliding contact receiving member has a sliding contact receiving surface which is slidably slidably contacted with a sliding contact surface of the sliding contact member. The density of the composition of the conductive agent in the peripheral region on the dynamic contact surface is distributed so as to be relatively higher than the density of the conductive agent in the central region on the sliding contact surface, whereby: The current concentrates on the particles or granular lumps having a relatively high density of the conductive agent composition in the peripheral region, so that the current passes on the sliding contact surface against the relatively reduced mutual resistance. However, the particles or granules of the relatively high density solid lubricant composition in the central region exclusively reduce the coefficient of friction on the sliding contact surface. It acts to.

According to a second aspect of the present invention, a copper-nickel alloy (Cu-N
i), tin (Sn) and titanium (Ti) particles or granular masses are relatively densely distributed in the peripheral region on the sliding contact surface, where current is concentrated, Boron nitride (BN), graphite, tungsten disulfide (WS ₂ ), mica (S
Particles or particles of (i, Al, K) are relatively densely distributed in the central region on the sliding contact surface, and act to reduce the friction coefficient there. According to a third aspect of the present invention, the sliding contact body is a cylindrical body formed of a sintered body, and one end surface thereof functions as a sliding contact surface.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. As shown in the perspective view of the main part extraction of FIG. 1, the sliding contact structure P is composed of a sliding contact body A and a sliding contact receiver B, and is fixed to the sliding contact body A. An electric current supplied from a connected power supply system (not shown) is fixedly connected to a sliding contact receiver B which is slidably opposed to the electric current via the sliding contact body A. Into the load system (not shown). As clearly shown in the partial cross-sectional perspective view of FIG.
In a hollow portion of a circular tube-like sleeve a1 made of, for example, boron nitride (BN), graphite,
Tungsten disulfide (WS ₂ ), mica (Si, Al,
The mixture a2 of the material particles such as K) is press-fitted to form a core portion, and the sleeve a1 and the mixture a2 of the core portion are subjected to an integral sintering process to form a sintered body. A cylindrical sliding contact body A is formed by the union a3. The sliding contact body A is provided with a sliding contact surface a4 formed in a flat surface at one end of a cylindrical body as the sliding contact body A. On the other hand, a sliding contact receiving member B disposed opposite to the sliding contact member A is driven by a rotation driving mechanism (not shown) connected to the center opening b1, and is a conductive disk that rotates counterclockwise in the drawing, typically. More specifically, the disk b2 is made of a copper (Cu) disk, and a sliding contact surface b3 formed in a plane is provided on the surface of the disk b2. The sliding contact receiving surface b3 is in sliding contact with the sliding contact surface a4 of the sliding contact body A so as to be relatively slidable. Both a mechanical mutual sliding function and an electrical interconnection function between them are simultaneously ensured. Copper (Cu) on the end surface of the cylindrical sleeve a1 is exposed in the peripheral region of the circular cross section as the sliding contact surface a4 of the sliding contact body A, and the core region is provided in the central region of the circular cross section. In the corresponding mixture a2, particles or granular lumps of the order of 100 microns of the solid lubricant composition are mixed in the form of a uniform distribution.

Returning to FIG. 1, the sliding contact body A having such a configuration will be described.
When the sliding contact surface a4 and the sliding contact receiving surface b3 are pressed and slid against the sliding contact receiving surface b3 of the sliding contact receiving member B, current flows between the sliding contact surface a4 and the sliding contact receiving surface b3. Concentrates on the sleeve a1 in the peripheral area on the sliding contact surface a4, passes therethrough with low resistance, and flows into the sliding contact B. In the meantime, tungsten disulfide (WS ₂ ), graphite, and the like rubbed out from particles or granular lumps of the solid lubricant composition contained in the sintered body a3 of the core portion in the central region on the sliding contact surface a4 are opposed to each other. By forming a lubricating film between the sliding contact surface a4 and the sliding contact surface b3 by also transferring to the moving sliding contact surface b3, the effect of gradually reducing the friction coefficient between the two surfaces is ensured.

Similarly, the sliding contact surface a of the sliding contact body A
A sintered body manufactured such that the density of the particles or granular lumps of the conductive agent composition on the surface 4 is higher in the peripheral region of the sliding contact surface a4 than in the central region of the sliding contact surface. FIG. 3 is a partial cross-sectional perspective view showing the universal structure of a3. In FIG. 3, the sintered body c3 extends along the central axis, extends along the outer periphery of the core portion c2, and a core portion c2 exposed as a central region on a sliding contact surface c4 at one end surface,
The outer peripheral portion c1 exposed as a peripheral region on the sliding contact surface c4 is integrally sintered so as to form a columnar body, and the core portion c2 has particles or particles of a solid lubricant composition. The agglomerates are densely distributed relative to that of the conductive agent composition, and particles or granular lumps of the conductive agent composition are densely distributed in the mantle portion c1 relative to that of the solid lubricant composition.

The change in the distribution density of the particles of the conductive agent composition in the buffer region near the boundary between the core portion c2 and the mantle portion c1 is discrete (step) as shown in FIG. ), But may be continuous as shown in the figure. Further, with respect to the composition of the conductive agent in the jacket portion c1, the distribution density of the copper (Cu) particles or granular lumps may be selectively increased, and the selective high-density distribution of such copper (Cu) particles or granular lumps may be obtained. As shown in FIG. 2, instead of the jacket portion c1, copper (C
The structure of the sintered body a3 employing the sleeve a1 made of u) can be grasped. Further, the composition of the outer tubular portion c1 in the sliding contact body A shown in FIG. 3 is not limited to copper (Cu), and is generally not limited to copper-nickel alloy ( A matrix material containing a conductive agent composition such as 90Cu-10Ni), tin (Sn), and titanium (Ti) is also suitably employed.

[0013]

FIG. 4 shows a perspective view of a sintered body d3 as a conventional sliding contact body A, which contains a conductive agent and solid lubricant particles or a granular mass in a uniform distribution. And a sliding contact surface d4 is provided on one end surface thereof. A sintered body d3 of such a conventional composite material manufactured under the following specifications (CMML-
1) was prepared as a reference sample for evaluating the performance of the sintered body c3 of the example of the present invention. [Shape and dimensions] Diameter: 8.5 mmφ cylindrical body [Composition (Wt%) of entire conductive material of sintered body d3] Copper / nickel alloy (90Cu-10Ni): 80.74
8 Tin (Sn): 7.099 Titanium (Ti): 0.887 [Composition of the entire solid lubricant of sintered body d3 (Wt%)] Boron nitride (BN): 0.229 Graphite: 2.364 2 Tungsten sulfide (WS ₂ ): 7.609 Mica: 1.064

Copper (C) having an appearance similar to that of FIG.
A cylindrical member made of u) having a sliding contact surface on one end surface is also frequently used as the sliding contact member A. Such a conventional sliding contact body A made of a metallic material, which was manufactured under the following specifications (Cu), was used as a reference specimen for evaluating the performance of the sintered body c3 of the embodiment of the present invention. Prepared as. [Shape and dimensions] Diameter: 8.5 mmφ cylindrical body [Whole conductive composition (Wt%)] Copper (Cu): 100 [Whole solid lubricant composition (Wt%)] None

In comparison with the above two reference samples, the sintered body c3 of the sample of the embodiment to be evaluated for performance is:
The following specifications (CMML-1W) were produced. [Shape and dimension] Outer diameter: 8.5 mmφ, sleeve with inner diameter 5.0 mmφ Core part with diameter 5.0 mmφ [Composition of conductive agent of outer part c1 (Wt%)] Copper / nickel alloy (90Cu-10Ni): 78. 66
9 Tin (Sn): 6.916 Titanium (Ti): 0.864 However, the composition of the solid lubricant was not contained. [Composition of lubricant of core portion c2 (Wt%)] Boron nitride (BN): 0.276 Graphite: 2.843 Tungsten disulfide (WS ₂ ): 9.152 Mica: 1.280 No composition is contained.

Here, the sintered body c3 of the sample (CMML-1W) of the embodiment to be evaluated for performance is a reference sample of the above-mentioned composite material in the weight% distribution of the contained composition per unit axial length (unit volume). The identity with the sintered body d3 of (CMML-1) is maintained. Therefore, only the conductive agent composition of the conductive agent composition and the solid lubricant composition that are uniformly distributed in the sintered body d3 of the reference sample (CMML-1) of the composite material is concentrated in the mantle portion c1. Then, it can be said that the structure in which all of the remaining lubricant composition is collected in the core portion c2 is the sintered body c3 of the sample (CMML-1W) of the example.

Returning again to FIG. 1, a reference specimen (CMML) of a composite material is applied to a sliding contact surface b3 on a copper (Cu) disk b2 which is rotationally driven as a sliding contact member B.
-1), the reference specimen (Cu) of the metal material and the specimen (CMML-1W) of the embodiment of the present invention,
The sliding contact surface is used to empirically compare and evaluate the electrical performance of the sample with respect to the reference sample by sliding the sample at a relative rotational speed of 10 RPM (a relative peripheral speed of 0.0105 m / sec) under a pressing force of 00 g. Resistance (electrical resistance) between the sliding contact surface and the sliding contact surface is measured as the total average value for each cumulative number of rotations (up to 500 times) of the disk b2, and the distance between the sliding contact surface and the sliding contact surface is measured. FIG. 5 is an electrical characteristic diagram plotted for each amount of current passing therethrough. Similarly, in order to empirically compare and evaluate the mechanical performance of the specimen with respect to the reference specimen, the sliding contact surface and the sliding contact receiving surface are compared. The friction coefficient between the discs is measured as a total average value for each cumulative number of rotations (up to 500 times) of the disk b2,
FIG. 6 is a mechanical characteristic diagram plotted for each amount of current passing between the sliding contact surface and the sliding contact receiving surface. According to the electrical characteristic diagram of FIG. 5, the sample (CMML-
The contact resistance of 1 W) is 3 in a passing current amount region of 10 A or less.
A reference sample of a composite material (CMML) showing a low value of about 4 mΩ and about 18 mΩ in a passing current amount range of 5 A or less.
Reference sample (Cu) of a metal material which is remarkably lower than that of -1) and exhibits 1-2 mΩ in a passing current amount region of 10 A or less.
Can be said to be roughly comparable to

Further, according to the mechanical characteristic diagram of FIG. 6, the friction coefficient of the sample (CMML-1W) according to the embodiment of the present invention is about 0.2 to 0.3 in a passing current amount range of 10 A or less. At the same passing current amount range, 1.2 to
The value is much lower than that of the reference sample (Cu) of the metal material showing 1.8, and furthermore, a gradual improvement is observed with respect to the value of the sample of the composite material (CMML-1) in the same passing current amount region. As described above, based on the electrical characteristics shown in FIG. 5 and the mechanical characteristics shown in FIG. 6, the sliding contact structure of the present invention has a function of gradually decreasing the friction coefficient due to the mixture of the solid lubricant particles or the granular mass. It achieves a drastic reduction in the overall electrical resistance on the sliding contact surface of the sintered body without any sacrifice, and enhances the electrical interconnection function on the sliding contact surface and improves the mechanical performance. It has been proved that it meets the demands of the trade-off of enhancing the mutual sliding contact function.

Each of the sintered bodies a3 and c3 of the sliding contact body A exemplified as the above-described embodiment is formed in a cylindrical body, and has a sliding contact surface a having a circular cross section on one end surface.
4 and c4, but the sliding contact surface a
4 and c4 are not limited to those having a circular cross section, because it is sufficient to ensure a mechanical mutual sliding function and an electric interconnection function between the sliding contact receiving surfaces b3 which are in sliding contact with each other. A triangular prism having a triangular shape or a rectangular body having a square cross section can also be appropriately employed, and if it is expanded, a three-dimensional body in the sense of including all of these and having a closed contour in a three-dimensional space is sufficient.

[Brief description of the drawings]

1 to 3 and FIGS. 5 to 6 relate to an embodiment of the present invention. FIG. 4 relates to the prior art.

FIG. 1 is a perspective view extracting and showing a main part of a sliding structure P. FIG.

FIG. 2 is a partial sectional perspective view showing an example of the structure of a sliding contact body A.

FIG. 3 is a partial sectional perspective view showing another example of the structure of the sliding contact body A.

FIG. 4 is a perspective view showing an example of the structure of a conventional sliding contact body A.

FIG. 5 shows sliding contact surfaces a4, c4, d4 and sliding contact receiving surface b3.
FIG. 5 is an electrical characteristic diagram showing an electric resistance between the first embodiment and the second embodiment.

FIG. 6 shows sliding contact surfaces a4, c4, d4 and sliding contact receiving surface b3.
FIG. 5 is a mechanical characteristic diagram showing a coefficient of friction between.

[Explanation of symbols]

 Reference Signs List A sliding contact body B sliding contact receiver P sliding contact structure a1 cylindrical sleeve c1 circular tube-like mantle part a2, c2 mixture (core part) a3, c3, d3 sintered body a4, c4, d4 Sliding contact surface b1 Center opening b2 Conductive disk b3 Sliding contact surface

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[Procedure amendment]

[Submission Date] April 18, 2001 (2001.4.1
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art Conventional structures of this type include copper and copper.
The composition of a conductive agent containing metal particles such as nickel alloy (Cu-Ni), tin (Sn), titanium (Ti), boron nitride (BN), graphite, tungsten disulfide (W
S ₂ ), a columnar sliding contact body formed of a sintered body in which the composition of a solid lubricant containing material particles such as mica (Si, Al, K) is uniformly distributed throughout, for example, It is frequently used as a sliding contact member for a brush of an electric motor, and a sliding contact surface is formed on one end surface of such a columnar sintered body, and for this sliding contact surface, for example, A conductive sliding contact member such as a copper ring which is frequently used for a slip ring of an electric motor or a metal flat plate which is frequently used as a sliding contact member of other industrial machines is slidably slidable relative to each other. A sliding contact structure configured as described above is known.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

In addition, the electric resistance at the sliding contact surface is further dependent on the interdependent action of the current flowing intensively on the particles or granular lumps of the conductive agent composition uniformly distributed on the sliding contact surface. The mechanism of the resulting mutual resistance is described in Greenwood's theory (Source: JA Greenwood, “Constric”
Tension resistance and ther
eal area of contact ", Brit.
J. Appl. Phys. , Vol. 17, pp. 16
21-1632, 1966), the inventor of the present application has enthusiastically continued empirical research on the application of this theory to the mechanism of generation of electrical resistance at the sliding contact surface of a sintered body. As a result, the conductive agent particles or granular mass uniformly distributed in the central region on the sliding contact surface,
The overall interaction from the current, which is concentrated point-wise on the conductive agent particles, etc. on the entire sliding contact surface, creates a relatively large mutual resistance, which creates a large electrical resistance on the sliding contact surface. While the resistance is substantially dominant, the conductive agent particles and the like distributed uniformly in the peripheral region on the sliding contact surface are exclusively concentrated at the conductive agent particles and the like in the peripheral region. The interaction from the current that generates only a relatively small mutual resistance, demonstrating that the current on the sliding contact surface concentrates on the conductive agent particles in these peripheral areas (Source: Y. Watanabe, Ana)
lysis of Contact Resistan
ce in Composite Materials
forSliding Contacts, IEIC
E Trans, Electron. Japan vo
l. E83-C No. 9. pp. 1409-1413
September 2000). According to the empirical elucidation of the present inventor, the mutual resistance of the green wood generated on the sliding contact surface of the sintered body is caused by the mixture of the particles of the solid lubricant or the lump on the particles for decreasing the friction coefficient there. Momentum, because it is the electrical resistance of the excess element exceeding the electrical resistance for the price
Even if the coefficient of friction gradually decreases, the electrical resistance generated on the entire sliding contact surface becomes large, and from that surface, there is a problem that the range of use of the conventional sliding contact structure is restricted. Was.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005] Therefore, by suppressing the electric resistance due to the mutual resistance of the excess elements to a minimum, without sacrificing the effect of decreasing the coefficient of friction due to the mixture of particles or granular lumps of the solid lubricant, It is an object of the present invention to provide a sliding contact structure in which the overall electric resistance on the sliding contact surface of the sintered body is reduced greatly.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 125/04 C10M 125/04 169/04 169/04 // C10N 10:02 C10N 10:02 10:08 10:08 10:12 10:12 10:16 10:16 20:00 20:00 Z 30:00 30:00 Z 40:02 40:02

Claims (3)

[Claims] 1. A sliding contact body provided with a sliding contact surface on one surface of a three-dimensional body formed of a sintered body comprising a composition of a conductive agent and a composition of a solid lubricant; A conductive sliding contact receiving surface having a sliding contact receiving surface that is slidably slidably contacted with the dynamic contact surface; and a peripheral area on the sliding contact surface of the sliding contact body. Wherein the density of the composition of the conductive agent is distributed so as to be relatively higher than the density of the conductive agent in the central region on the sliding contact surface. . 2. The composition of the conductive agent of the sliding contact body is copper.
It contains nickel alloy (Cu-Ni), tin (Sn), and titanium (Ti), and the composition of the solid lubricant of the sliding contact body is boron nitride (BN), graphite, tungsten disulfide (WS ₂ ) The sliding contact structure according to claim 1, comprising mica (Si, Al, K). 3. The sliding contact body has a sliding contact surface on one end surface of a cylindrical body formed of the sintered body.
The sliding contact structure as described in the above.