JP3420380B2 - Sliding surface structure and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding surface structure, and more particularly to a sliding surface structure composed of an aggregate of metal crystals and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, for example, in a gear device, the meshing surface of the gear is roughened by machining or the like, and the meshing surface is solid lubricant such as molybdenum disulfide or graphite, or semi-solid lubrication such as grease. It is known to retain the agent.

However, the conventional meshing surface is simple from a microscopic point of view and has a low ability to retain a solid lubricant or the like, resulting in poor seizure resistance under high load conditions.

Therefore, the present applicant has previously developed, for example, a sliding surface structure formed on the meshing surface of a gear having a large number of pyramidal metal crystals on the sliding surface (for example,
(See Japanese Patent Laid-Open No. 6-174089).

According to this structure, the adjacent pyramidal metal crystals are in a state of being bitten into each other, so that the sliding surface is formed with a large number of fine ridges and between these ridges. Since it has an intricate appearance consisting of a large number of minute valleys and a large number of minute ridges due to the mutual erosion of the ridges, the retention of the sliding surface structure on the solid lubricant, etc. is improved. . This improves the seizure resistance of the sliding surface structure.

[0006]

However, various studies have been made on the sliding surface structure in order to cope with a more severe sliding environment such as sudden and excessive load fluctuation in the gear. It has been found that it is necessary to further improve the holding property of the sliding surface component with respect to the solid lubricant and the like.

An object of the present invention is to provide the above-mentioned sliding surface structure and the manufacturing method thereof, which can satisfy the above-mentioned demands.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to a sliding surface structure constituted by an aggregate of metal crystals, wherein the area ratio A of the pyramidal metal crystals on the sliding surface is 40% ≦ A ≦ 100%.
Further, at least a part of the pyramidal metal crystals is a deformed pyramidal metal crystal having at least one notched recess at at least one ridge portion, and the deformed pyramidal metal crystal on the sliding surface. Pseudo area ratio B of 20
% ≦ B ≦ 100%.

The present invention divides the electroplating process into a plurality of steps in manufacturing the sliding surface structure composed of the aggregate of metal crystals by the electroplating process using the pulse current method. An energization stopping step is interposed between the previous step and the current step, and the time T required for the energization stopping step is T.
₂ and the minimum current maintaining time T ₁ in the previous process, T
The relationship of ₂ ≧ 100T ₁ is established, and the relationship of CD ₂ ≧ 1.2CD ₁ is established between the average cathode current density CD ₂ in the present process and the average cathode current density CD ₁ in the previous process. And

[0010]

When the area ratio A of the pyramidal metal crystals is set as described above, the two adjacent pyramidal metal crystals are in a state of being bite into each other, and therefore the sliding surface has many fine peaks. , A complex lubricant consisting of a large number of minute valleys formed between the peaks and a large number of minute valleys caused by the mutual biting of the peaks, so that a solid lubricant and semi-solid lubrication Exhibits good retention of the agent. Moreover, since the pseudo-area ratio B of the irregularly shaped pyramidal metal crystals is set as described above, the notched recesses of those metal crystals exert an anchoring effect on the solid lubricant or the like, whereby the holding property is improved. Doubled.

In such a sliding surface structure, even if it is placed in a harsh sliding environment, the above retaining property of the sliding surface structure is maintained at a high level under lubrication, while on the other hand, under unlubricated condition. Then, the sliding load is dispersed by a large number of fine pyramidal metal crystals. As a result, the sliding surface structure exhibits excellent seizure resistance under lubrication and non-lubrication.

The area ratio A of the pyramidal metal crystal is A <4.
0% is not desirable because the sliding surface tends to be simplified.
If the pseudo area ratio B of the irregularly shaped pyramidal metal crystal is B <20%, the anchor effect cannot be expected.

According to the above-mentioned manufacturing method, the above sliding surface structure can be easily mass-produced. However, T ₂
When <100T ₁ or CD ₂ <1.2CD ₁ , the pseudo-area ratio B of the irregular-shaped pyramidal metal crystal is B <20%.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a gear device 1 shown in FIG. 1, two gears 2 ₁ and 2 ₂ meshing with each other are made of steel, and a meshing surface 3 of at least one gear 2 ₁ is electroplated to form a layered sliding surface. The structure 4 is formed.

In the embodiment, the sliding surface structure 4 is composed of an aggregate of metal crystals having a body-centered cubic structure (bcc structure) as shown in FIG. As shown in FIG. 3, the aggregate has a large number of columnar crystals 5 grown from the meshing surface 3, and these columnar crystals 5 have Miller index (hhh) planes and sliding surfaces 4a.
Oriented (hhh) oriented metal crystal, or (2hhh) plane with a Miller index oriented toward the sliding surface 4a side (2hhh)
h) At least one of oriented metal crystals.

As described above, the columnar crystal 5 having the bcc structure has a (hhh) surface oriented toward the sliding surface 4a side with a Miller index (hh).
hh) In the case of an oriented metal crystal, its tip is
As shown in, the hexagonal pyramidal metal crystal (pyramidal metal crystal) 6 can be formed on the sliding surface 4a. The hexagonal pyramidal metal crystal 6 has a smaller average particle diameter than the triangular pyramidal metal crystal (pyramidal metal crystal) which is also a (hhh) oriented metal crystal, and the particle diameter is substantially uniform. In the hexagonal pyramidal metal crystal 6 and the like, there is a correlation between the grain size and the height, and therefore the grain size being substantially uniform means that the heights are also substantially equal.

As shown in FIGS. 3 and 5 (a), at least a part of the hexagonal pyramidal metal crystals 6 is an irregular hexagonal pyramidal metal crystal (an irregular pyramidal metal crystal) 6 ₁ . The odd-shaped hexagonal pyramidal metal crystal 6 ₁ is provided with at least one, at least one in the six ridge line portions 7 in the illustrated example, and one notch-shaped recess 8 in the illustrated example.

The hexagonal pyramidal metal crystal 6 has a structure shown in FIGS.
As also clearly shown, a normal hexagonal pyramidal metal crystal 6 ₂ having no notch-shaped recess 8 in the ridge 7 is also included.

The area ratio A of the hexagonal pyramidal metal crystals 6 such as the normal and irregular hexagonal pyramidal metal crystals 6 ₂ and 6 _{1 on} the sliding surface 4a is set to 40% ≦ A ≦ 100%. This area ratio A is A = (c / b) × 100 (%), where b is the area of the sliding surface 4a and c is the area occupied by all the hexagonal pyramidal metal crystals 6 on the sliding surface 4a. Was asked for.

Further, the pseudo area ratio B of the deformed hexagonal pyramidal metal crystal 6 _{1 on} the sliding surface 4a is set to 20% ≦ B ≦ 100%. The pseudo area ratio B was obtained by the following method. That is, as shown in FIG. 3, in the vertical cross section of the sliding surface structure 4, the growth direction of the columnar crystal 5 is set so as to pass through the bottom of the normal or irregularly shaped hexagonal pyramidal metal crystal 6 ₂ , 6 ₁ or its vicinity. A reference line segment d having a predetermined length L ₁ is defined in the orthogonal direction. Further, in the same direction as the length direction of the reference line segment d, the length at or near the bottom of the deformed hexagonal pyramidal metal crystal 6 ₁ is L _2, and all the deformed hexagonal pyramids included in the reference line segment d The sum of the lengths L ₂ of the metal crystals 6 ₁ is nL ₂ (n
Is the number of odd-shaped hexagonal pyramidal metal crystals 6 ₁ , n = 4 in the illustrated example)
Was calculated as B = (nL ₂ / L ₁ ) × 100 (%). A micrograph is used for this calculation. The reason why such a method is adopted is that even if the sliding surface 4a is observed with a microscope from above, the irregular hexagonal pyramidal metal crystal 6 ₁ cannot be discriminated.

When the area ratio A of the hexagonal pyramidal metal crystal 6 on the sliding surface 4a is set as described above, adjacent ones of the hexagonal pyramidal metal crystal 6 bite into each other as shown in FIG. It becomes a state. As a result, the sliding surface 4a has a large number of extremely fine ridges 9, a large number of extremely fine valleys 10 formed between the ridges 9, and a large number of poles due to the mutual biting of the ridges 9. Since it has a very intricate appearance composed of the fine sloping portions 11, it exhibits a good holding property for the solid lubricant and the semi-solid lubricant. Moreover, since the pseudo-area ratio B of the deformed hexagonal pyramidal metal crystal 6 ₁ is set as described above, the notched recesses 8 of the metal crystal 6 ₁ exert the anchor effect on the solid or semi-solid lubricant. However, this doubles the retention.

In such a sliding surface structure 4, even if it is placed in a harsh sliding environment, the above retaining property of the sliding surface structure 4 is maintained at a high level under lubrication. Under lubrication, a large number of fine hexagonal pyramidal metal crystals 6 can disperse the sliding load. As a result, the sliding surface structure 4 exhibits excellent seizure resistance under lubrication and non-lubrication.

Further, along with the uniform miniaturization of the hexagonal pyramidal metal crystal 6, it is possible to avoid locally increasing the surface pressure and to achieve fine differentiation of the sliding load, whereby the sliding surface structure 4 is formed. Excellent wear resistance is exhibited not only under lubrication but also under non-lubrication.

When the columnar crystals having the bcc structure are oriented metal crystals (2hhh) whose Miller index is (2hhh) faced to the sliding surface 4a side, the tips thereof are small pyramidal metal crystals (pyramidal metal). Crystal).

Even when the hexagonal pyramidal metal crystal and the small pyramidal metal crystal are mixed on the sliding surface, the area ratio A of the pyramidal metal crystal is 40% ≦ A ≦ 100 as described above.
Set to%. Further, even when irregularly shaped hexagonal, trigonal, and small pyramidal metal crystals are mixed on the sliding surface, the pseudo area ratio B of the irregularly shaped pyramidal metal crystals is 20% ≦ B ≦ 100 similarly to the above.
Set to%.

As shown in FIG. 6, the inclination of the (hhh) plane with respect to the virtual surface 12 along the sliding surface 4a appears as the inclination of the hexagonal pyramidal metal crystal 6, so that the sliding surface constituting body 4 is held as described above. And wear resistance. Therefore, (hh
h) The inclination angle θ formed by the surface with respect to the virtual surface 12 is 0 ° ≦ θ ≦
It is set at 15 °. In this case, the inclination direction of the (hhh) plane is not limited. When the inclination angle θ becomes θ> 15 °, the holding property and wear resistance of the sliding surface structure 4 deteriorate. This inclination angle θ is the same for the (2hhh) plane.

As a metal crystal having a bcc structure, F is
Examples thereof include crystals of e, Cr, Mo, W, Ta, Zr, Nb, V, etc., or alloys thereof.

In the electroplating process for forming the sliding surface structure 4, the plating bath conditions in the case of performing the electric Fe plating process are as shown in Table 1.

[0029]

[Table 1]

The pH of the plating bath is adjusted with aqueous ammonia.

The electric Fe plating process is divided into two or more steps in the embodiment, and the pulse current method is applied as the energizing method in the first and second steps. In the pulse current method, as shown in FIG. 7, the current I of the plating power source is
The current I rises from the minimum current Imin (including Imin = 0) to reach the maximum current Imax, and then the minimum current Imin.
It is controlled so as to draw a pulse waveform as the time T elapses as it goes down.

First step (previous step) and second step (current step)
And an energization stopping step for making the energization current zero, there is a relationship of T ₂ ≧ 100T ₁ between the time T ₂ required for the energization stopping step and the minimum current maintaining time T ₁ in the first step. Is established. In this case, the minimum current maintaining time T ₁ in the first step is set to T ₁ ≧ 2.2 msec.

The average cathode current density C in the second step
The relationship of CD ₂ ≧ 1.2 CD ₁ is established between D ₂ and the average cathode current density CD ₁ in the first step. In this case, the average cathode current density CD ₁ in the first step is CD ₁
≧ 2.2 A / dm ^2, and the maximum cathode current density CDmax in the first and second steps is CDmax ≧ 2.6.
Set to A / dm ² .

Further, the energization time from the start of the rise of the current I to the start of the fall is T _3, and the cycle time from the start of the previous rise to the start of the next rise is set as T ₄ . At this time, the ratio between the energization time T ₃ and the cycle time T ₄ , that is, the time ratio T ₃ / T ₄ is
In the process, T ₃ / T ₄ ≦ 0.45 is set. T ₃
If / T ₄ > 0.45, depending on other conditions, pyramidal F
The area ratio A of the e crystal on the sliding surface may be A <40%.

By applying such an electric Fe plating treatment, the sliding surface structure 4 having the above structure can be easily mass-produced.

A specific example will be described below. EXAMPLE 1 Chromium molybdenum steel assumes gear 2 ₁ (JIS SCM420, carburized material) on one side peripheral portion of the disk made of the first and second steps or electrical Fe plating process consisting of only the first step, By applying F
A sliding surface structure 4 having a thickness of 15 μm and composed of an aggregate of e crystals was formed.

Table 2 shows the plating bath conditions of Examples 1 to 15 of the sliding surface structure, and Tables 3 and 4 show the energization conditions of Examples 1 to 15, respectively.

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

Table 5 shows the abundance S of each oriented Fe crystal in Examples 1 to 15.

[0042]

[Table 5]

The abundance S is the X-ray diffraction pattern (X
The line irradiation direction was calculated from the following formula based on the direction perpendicular to the sliding surface). FIG. 8 shows the example 1, FIG. 9 shows the example 11, and FIG.
0 is the X-ray diffraction pattern of Example 15. Note that, for example, {11
The 0} oriented Fe crystal means an oriented Fe crystal in which the {110} plane faces the sliding surface side. {110} oriented Fe crystal: S ₁₁₀ = {(I ₁₁₀ / IA ₁₁₀ ) / T} × 100, {200} oriented Fe crystal: S ₂₀₀ = {(I ₂₀₀ / IA ₂₀₀ ) / T} × 100, {211} oriented Fe crystal: S ₂₁₁ = {(I ₂₁₁ / IA ₂₁₁ ) / T} × 100, {310} oriented Fe crystal: S ₃₁₀ = {(I ₃₁₀ / IA ₃₁₀ ) / T} × 100, {222} oriented Fe crystal: S ₂₂₂ = {(I ₂₂₂ / IA ₂₂₂ ) / T} × 100 where I ₁₁₀ , I ₂₀₀ , I ₂₁₁ , I ₃₁₀ , and I ₂₂₂ are X-ray reflection intensities of the respective crystal planes. IA ₁₁₀ , IA ₂₀₀ , IA ₂₁₁ , IA ₃₁₀ , IA ₂₂₂ is the X-ray reflection intensity ratio of each crystal plane in the ASTM card,
IA ₁₁₀ = 100, IA ₂₀₀ = 20, IA ₂₁₁ = 30,
IA ₃₁₀ = 12 and IA ₂₂₂ = 6. Furthermore, T is T
= (I ₁₁₀ / IA ₁₁₀ ) + (I ₂₀₀ / IA ₂₀₀ ) + (I
₂₁₁ / IA ₂₁₁ ) + (I ₃₁₀ / IA ₃₁₀ ) + (I ₂₂₂ /
IA ₂₂₂ ).

Table 6 shows the crystal morphology of the sliding surface, the area ratio A and the grain size of the hexagonal pyramidal Fe crystal on the sliding surface, the pseudo area ratio B of the deformed hexagonal pyramidal Fe crystal and the sliding surface for Examples 1 to 15. The hardness in the longitudinal section of the structure is shown respectively.

[0045]

[Table 6]

The grain size of the hexagonal pyramidal Fe crystal is the average value of the distances between the two opposite corner portions with the apex interposed, that is, the lengths of the three diagonal lines. Pseudo-area ratio B of irregularly shaped hexagonal pyramid Fe crystal
For the calculation of, a notch is formed in the disc, and then the disc is cooled in liquid nitrogen for 5 minutes or more,
After that, the disc and the sliding surface structure are broken at the notch portion, a microscopic photograph is taken of the longitudinal section of the sliding surface structure, and the pseudo area ratio B is determined by the method described above based on the photograph.

In Example 1, FIG. 11 (a) is a micrograph showing the crystal structure of the sliding surface, and FIG. 11 (b) is a micrograph showing the crystal structure of the longitudinal section, and FIG. 11 (c) is the same figure ( b)
FIG. A large number of hexagonal pyramidal Fe crystals are observed in FIG. In this case, as shown in Table 6,
The area ratio A of the hexagonal pyramidal Fe crystal is A = 100%. This hexagonal pyramidal Fe crystal has a (hhh) plane, and therefore {22
As shown in Table 5 and FIG. 8, the presence rate S of the {222} oriented Fe crystal was S = 96.2. %. In addition, these hexagonal pyramidal Fe crystals have different shapes of hexagonal pyramidal Fe provided with notched recesses, as is apparent from FIGS.
It is a crystal, and its pseudo area ratio B is B as shown in Table 6.
= 100%.

FIG. 12 is a micrograph showing the crystal structure of the sliding surface in Example 11, in which a large number of hexagonal pyramidal Fe crystals are observed. In this case, as shown in Table 6, hexagonal pyramidal Fe
The area ratio A of the crystal is A = 100%. This hexagonal pyramid F
The e crystal is a {222} oriented Fe crystal as described above,
As shown in Table 5 and FIG. 9, the existence rate S is S = 96.
5%. However, these hexagonal pyramidal Fe crystals are normal hexagonal pyramidal Fe crystals, and therefore, irregular hexagonal pyramidal Fe crystals
The pseudo area ratio B of the crystal is B = 0% as shown in Table 6.

FIG. 13 is a micrograph showing the crystal structure of the sliding surface in Example 15, and a large number of granular Fe crystals are observed. In this case, as shown in Table 6, the area ratio A of the hexagonal pyramidal Fe crystal is A = 0%.

Next, using the disks having Examples 1 to 15, a seizure test by a chip-on-disk method was conducted under lubrication to measure the seizure generation load. The results shown in Table 7 were obtained. The test conditions are as follows. Chip material : Chromium molybdenum steel (JIS SCM420, carburized material); Disk peripheral speed : 15 m / sec; Lubrication method: Molybdenum disulfide coating on the surface of example 1 of the disk;
Area of sliding surface of the chip: 1 cm ² ; Load application method for the chip: First, apply a load of 20 N and hold the state for 2 minutes, then increase the load to 20 N and the state with each increase. Hold for 2 minutes.

[0051]

[Table 7]

FIG. 14 shows the relationship between the area ratio A of hexagonal pyramidal Fe crystals and the seizure load. In the figure, points (1) to (1
5) corresponds to Examples 1 to 15, respectively.

In FIG. 14, Examples 1 to 13 and Examples 14 and 1
Comparing with No. 5, the seizure load is significantly higher in the former than in the latter. From this, it is understood that the area ratio A of the hexagonal pyramidal Fe crystal on the sliding surface should be set to A ≧ 40%.

Further, when the area ratio A ≧ 40%, Example 1
7 to Examples 8 to 13, the former has better seizure resistance than the latter. From this, it is understood that the pseudo area ratio B of the irregular-shaped hexagonal pyramid Fe crystal may be set to B ≧ 20%.

Next, the dynamic friction coefficient μ was measured by the tip-on-disk method under lubrication using the disks having Examples 1 to 3 and 11 to 15, and the results shown in Table 8 were obtained. The test conditions are as follows. Chip material: Chromium molybdenum steel (JIS SCM420, carburized material); Disk peripheral speed: 15 m / sec; Lubricant: Room temperature 10W-3
0 (SAE viscosity classification) equivalent lubricating oil; Lubrication amount: 40 ml / mi
n: Area of sliding surface of chip: 1 cm ² ; Method of applying load to chip: First, apply a load of 50 N and hold in that state for 2 minutes, and thereafter increase the load to 50 N and with each increase, Hold in that state, and when the load reaches 250 N, hold in that state for 5 minutes to obtain a coefficient of dynamic friction μ
Is measured.

[0056]

[Table 8]

FIG. 15 shows the relationship between the area ratio A of hexagonal pyramidal Fe crystals and the dynamic friction coefficient μ. In the figure, points (1) to (3),
(11) to (15) correspond to Examples 1 to 3 and 11 to 15, respectively.

As is apparent from FIG. 15, when the area ratio A of the hexagonal pyramidal Fe crystal on the sliding surface is A ≧ 40%,
The dynamic friction coefficient μ of Examples 1 to 3 in which heteromorphic hexagonal pyramid Fe crystals are present on the sliding surface is substantially equal to or exactly equal to the dynamic friction coefficient μ of Examples 11 to 13 in which it is not present. From this,
It can be seen that the presence of irregularly shaped hexagonal pyramidal Fe crystals on the sliding surface has no effect on the wear resistance of the sliding surface structure. [Example 2] Chrome molybdenum steel (JIS SCM42
0, the gear 2 ₁ of meshing surface 3 made of carburized material), first
Then, by performing the electric Fe plating treatment in the second step, a sliding surface structure 4 having a thickness of 15 μm and formed of an aggregate of Fe crystals was formed.

Table 9 shows the plating bath conditions of Examples 1 to 12 of the sliding surface structure, and Tables 10 and 11 show the energization conditions of Examples 1 to 12, respectively.

[0060]

[Table 9]

[0061]

[Table 10]

[0062]

[Table 11]

Table 12 shows each oriented Fe in Examples 1-12.
The abundance S of crystals is shown. The method of obtaining the existence rate S is the same as that in the first embodiment.

[0064]

[Table 12]

Table 13 shows the crystal morphology of the sliding surface, the area ratio A and the grain size of the hexagonal pyramidal Fe crystal on the sliding surface, the pseudo area ratio B of the irregular hexagonal pyramidal Fe crystal and the sliding surface for Examples 1 to 12. The hardness in the longitudinal section of the structure is shown respectively. The method for determining the area ratio A, the particle size, and the pseudo area ratio B is described in Example 1.
Is the same as.

[0066]

[Table 13]

FIG. 16 shows the relationship between the average cathode current density CD ₂ and the pseudo area ratio B of the irregular hexagonal pyramidal Fe crystal in the second step for each time T ₂ required for the energization stopping step. In the figure, points (1) to (12) correspond to Examples 1 to 12, respectively.

As is apparent from Table 13 and FIG. 16, Example 1
In Nos. 3 and 6, the pseudo area ratio B of the deformed hexagonal pyramidal Fe crystal on the sliding surface is B ≧ 20%. From this, in order to satisfy B ≧ 20%, the relationship of T ₂ ≧ 100T ₁ is established between the time T ₂ required for the energization stopping step and the minimum current maintaining time T ₁ in the first step, and Second
CD ₂ ≧ 1.2 C between the average cathode current density CD ₂ in the step and the average cathode current density CD ₁ in the first step
It can be said that it is necessary to establish the relationship of D ₁ .

The present invention is not limited to gears, but is also applicable to constant velocity joints, upper arms, which are provided with solid or semi-solid lubricants.
It is also applied to lower arms. In this case, the response is improved by friction down.

[0070]

EFFECTS OF THE INVENTION According to the present invention, by having the structure specified as described above, the retention of solid and semi-solid lubricants is good, the load change is rapid and excessive. It is possible to provide a sliding surface structure that exhibits excellent sliding characteristics in a more severe sliding environment such as.

Further, according to the present invention, it is possible to provide a manufacturing method capable of easily mass-producing the sliding surface structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part of a gear device.

FIG. 2: Body-centered cubic structure and its (hhh) plane, (2h
It is a perspective view which shows the hh) surface.

FIG. 3 is an enlarged view of a portion indicated by an arrow 3 in FIG.

FIG. 4 is a view on arrow 4 of FIG.

FIG. 5A is a perspective view of a deformed hexagonal pyramidal metal crystal;
(B) is a perspective view of a normal hexagonal pyramidal metal crystal.

FIG. 6 is an explanatory diagram showing an inclination of a (hhh) plane in a body-centered cubic structure.

FIG. 7 is an output waveform diagram of an electroplating power supply.

8 is an X-ray diffraction diagram of Example 1. FIG.

9 is an X-ray diffraction pattern of Example 11. FIG.

10 is an X-ray diffraction pattern of Example 15. FIG.

11 (a) is a micrograph showing a crystal structure of a sliding surface, FIG. 11 (b) is a crystal structure of a longitudinal section, and FIG. 11 (c) is an enlarged view of an essential part of FIG. Is.

12 is a micrograph showing a crystal structure of a sliding surface of Example 11. FIG.

FIG. 13 is a micrograph showing a crystal structure of a sliding surface of Example 15.

FIG. 14 is a graph showing the relationship between the area ratio A of hexagonal pyramidal Fe crystals and the seizure load.

FIG. 15: Area ratio A of hexagonal pyramidal Fe crystal and dynamic friction coefficient μ
It is a graph which shows the relationship of.

FIG. 16 is a graph showing the relationship between the average cathode current density CD ₂ and the pseudo area ratio B of irregularly shaped hexagonal pyramidal Fe crystals in the second step.

[Explanation of symbols]

4 Sliding surface structure 4a Sliding surface 6 Hexagonal pyramidal metal crystal (pyramidal metal crystal) 6 ₁ Heteropyramidal pyramidal metal crystal (heteromorphic pyramidal metal crystal) 7 Ridge portion 8 Notched recess

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsumune Tabata 1-4-1 Chuo, Wako-shi, Saitama Inside of Honda R & D Co., Ltd. (56) Reference JP-A-6-313479 (JP, A) JP Japanese Patent Laid-Open No. 6-174089 (JP, A) Japanese Patent Laid-Open No. 6-316785 (JP, A) Japanese Patent Laid-Open No. 5-10334 (JP, A) Japanese Patent Laid-Open No. 2-22491 (JP, A) Japanese Patent Laid-Open No. 7-113195 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C25D 7/00 C25D 5/18 F16C 33/12

Claims (4)

(57) [Claims] 1. A sliding surface structure composed of an aggregate of metal crystals, wherein the area ratio A of the pyramidal metal crystals on the sliding surface is 40% ≦ A ≦ 100%, and the pyramidal metal crystals are Is a deformed pyramidal metal crystal having at least one notch-shaped recess in at least one ridge portion, and the pseudo area ratio B of the deformed pyramidal metal crystal on the sliding surface is 20% ≦. A sliding surface structure characterized in that B ≦ 100%. 2. The metal crystal has a body-centered cubic structure, and the pyramidal metal crystal has a mirror index (hhh) plane oriented toward a sliding surface (hhh) oriented metal crystal, or a mirror index. With the (2hhh) surface facing the sliding surface side (2hhh)
The sliding surface structure according to claim 1, which is at least one of oriented metal crystals. 3. The metal crystal is an Fe crystal, and the pyramidal metal crystal is a hexagonal pyramid-shaped (hhh) oriented Fe crystal with a mirror index of (hhh) plane facing a sliding surface side. The sliding surface structure according to claim 1 or 2. 4. When manufacturing a sliding surface structure composed of an aggregate of metal crystals by electroplating using a pulse current method, the electroplating is divided into a plurality of steps, and a previous step and a current step. An energization stop step is interposed between the step and the step, and T ₂ ≧ 100T ₁ between the time T ₂ required for the energization stop step and the minimum current maintaining time T ₁ in the previous step.
And the average cathode current density CD ₂ in the current process and the average cathode current density CD in the previous process are satisfied.
_A method of manufacturing a sliding surface structure, characterized in that a relationship of CD ₂ ≧ 1.2 CD ₁ is established with respect to ₁ .