JPH11140687A - Method of plating cylindrical member for eddy current type decelerating device, and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of plating a cylindrical member of a rotor to be mounted on an eddy current type decelerating device where the inner quality of the surface film is excellent and the plating is thick, and its device. SOLUTION: In this method, the plating is achieved while rotating a cylindrical member and a friction roller using a plating device where an anode electrode 15 is provided at a center part of a cylindrical member 1 and a friction roller 16 in contact with an inner surface of the cylindrical member is provided. In the plating device, a stay 19 to support the cylindrical anode electrode 15 is provided at the center part of a plating tank 22, the friction roller 16 supported by a support arm 25 extending from the stay and a bearing 26 fixed to a plating tank is provided, and a rotary shaft 20 to support a rotary arm 18 of a holder 17 to hold the cylindrical member 1 of a plated rotor is provided in the stay.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for plating an inner surface of a cylindrical member of a rotor of an eddy current type reduction gear installed in an automobile.

[0002]

2. Description of the Related Art In addition to a foot brake serving as a main brake and an exhaust brake serving as an auxiliary brake, a braking device for a vehicle performs stable deceleration on a downhill on a long slope and prevents burnout of the foot brake. For this purpose, an eddy current type reduction gear (hereinafter referred to as "retarder") is used. This retarder includes one using an electromagnet as a magnet and one using a permanent magnet. Some examples of the structure of a retarder using a permanent magnet have already been proposed by the present applicant (for example, Japanese Patent Application Laid-Open Nos. 1-234043, 1-234045, 1-298948). Reference).

FIG. 2 is a longitudinal sectional view showing an example of a retarder using a permanent magnet.

[0004] The retarder includes a rotor R attached to a rotating shaft 6 of a transmission and the like, and a stator S attached to a transmission case and the like.

The rotor R includes a cylindrical member 1 made of a ferromagnetic material,
It is composed of spokes 2, discs 3 and fins 4, and is attached to one end of the rotating shaft 6 via a bracket 5 with bolts. The cylindrical member 1 has its end joined to the tip of the spoke 2 inserted into the disk 3 by welding in a cantilever manner.

[0006] The stator S has a support ring 8 around which a plurality of permanent magnets 7 are provided with the polarity of the outer peripheral surface adjacent thereto being reversed.
Pole piece 9, casing 10, guide rod 11, drive unit 1
2, and a piston rod, and is provided inside the cylindrical member 1 of the rotor R. The support ring 8 with the permanent magnet 7 is a casing 1 formed in the shape of a hollow ring.
0, it is supported and incorporated by a guide rod 11 (see the lower half of the figure), and is incorporated by a piston rod 13 of a driving device 12 so as to be able to reciprocate in the axial direction of the rotation axis along the guide rod. ing.

The state where the permanent magnet 7 is inserted to the position of the pole piece 9 by this reciprocating movement, that is, the position where the permanent magnet 7 is magnetically opposed to the cylindrical member 1 (the state shown in the upper half of FIG. 2) is brake-on. On the other hand, a state in which the permanent magnet 7 is located at a position away from the pole piece 9 (a state shown in the lower half of FIG. 2) is braking off. The pole piece 9 is made of a soft ferromagnetic material, and is provided between the permanent magnet 7 and the cylindrical member 1 as shown in FIG. 2, and serves as a magnetic field path to the cylindrical member.

In the brake-on state, the cylindrical member 1 rotates across the magnetic flux emitted from the permanent magnet 7, so that an eddy current flows near the inner wall surface of the cylindrical member. The interaction between the eddy current and the magnetic flux generates a braking torque in the rotor.
The temperature of this cylindrical member is increased by Joule heat due to the eddy current, and is cooled and cooled by the fins 4 in a brake-off state.

In a permanent magnet type retarder or an electromagnet type retarder as well, as a measure for improving the generation of braking torque, a metal layer made of a material having a small electric resistance is plated on a surface of the rotor cylindrical member or the disk facing the magnet. It has been proposed. For these metal layers, copper or a copper alloy is used, and one composed of a single metal layer and one composed of a multilayer film such as nickel-copper-nickel have been proposed. See JP-A-63-274359, JP-A-64-30450, and JP-A-1-288636.

Conventionally, a copper sulfate plating bath for electroforming has been used for plating the inner surface of the cylindrical member of the retarder. The plating step is performed in the following steps (A) to (G).

(A) Cleaning → (B) Masking by electrodeposition coating →
(C) Polishing of the surface to be plated → (D) Cleaning → (E) Underground strike treatment with copper cyanide plating bath → (F) Thick plating treatment with copper sulfate plating bath → (G) Polishing of plating surface It is a figure which shows the cylindrical member of a retarder, (a) is a longitudinal cross-sectional view, (b) is a top view. The cylindrical member 1 of the retarder to be plated is in a state in which no spokes are welded, but a fin 4 is attached to the outer peripheral surface. Therefore, except for the inner surface (plated surface 14) of the cylindrical member, the masking (step B) is performed on the side surfaces and the fins. The underlayer strike process in (Step E) and the thick plating process in (Step F)
A copper electrode is installed at the center of the axis of the cylindrical member, and the plating is performed while stirring the plating bath using the cylindrical member as a negative electrode.

The thickness of each plating is 1-2 μm in the underlayer strike treatment in (Step E) and 100-200 μm in the thick plating treatment in (Step F). The undercoat treatment is performed in the copper cyanide plating bath because the copper sulfate plating bath corrodes the steel and cannot directly plate the steel. Copper cyanide plating baths are not suitable for thick plating, but are used as groundwork because they do not corrode steel.

[0013]

The cylindrical member plated by the above method was assembled in a retarder, and after a braking test was conducted, the cylindrical member was examined to find out the following.

(1) Usually, a brightener containing sulfur is added to a copper sulfate plating bath in order to smooth a plated surface. Since this sulfur is eutectoid in the plating layer, when the cylindrical member is incorporated in the retarder and exposed to a high temperature, the sulfur is diffused and concentrated at the interface, and the plating layer is separated.

(2) Since the tensile elongation of the plating layer plated in the plating bath to which the brightener is added is reduced to about 1/3 as compared with that of the plating layer without the addition of the brightening agent, the braking on or off is switched. Cracks occur due to expansion and contraction.

(3) Since the copper plating layer is soft and easily damaged, a protective film such as a nickel-phosphorus alloy is coated on this layer. However, when the mechanical polishing of the plated surface is performed as shown in (G) of the above process, abrasive grains may remain on the plated surface, and when these abrasive grains cover the protective film, they become pit defects.

As shown in FIG. 2, as the inner peripheral portion of the cylindrical member of the rotor of the retarder rotates closer to the pole piece, the braking torque is increased by the presence of the copper plating layer (100 to 500 μm). Is more likely to occur. In addition, as described above, since the temperature of the cylindrical member is raised to about 600 ° C. and the cooling is repeated by switching the braking on or off, the plating layer has no defects, and a flexible and dense structure is required. .

For this reason, for example, in order to increase the thickness of the copper layer by using a copper sulfate plating bath, the plating thickness is set to be greater than the required thickness, and then the required thickness is finished by mechanical polishing or the like. . In addition, in order to obtain a flexible and dense structure with no defects in the plating layer, it is necessary to adjust the current density and the arrangement of the electrodes in addition to stirring the plating bath, adding brighteners and surfactants. there were. In addition, the conventional method has the following disadvantages.

The copper sulfate plating bath corrodes steel,
It is necessary to cover the non-plated surface with a corrosion-resistant paint, etc.
In addition to prolonging the plating process time, it requires a mechanical polishing process, all of which lead to cost increases.To make the surface properties of the plating surface more uniform, more precise control is required. Stirring, adjustment of current density and arrangement of electrodes are required, and equipment remodeling is required.Brightener is added to the plating solution to make the plating layer dense and smooth. In many cases, these decomposed impurities deposit on the plating layer and deteriorate the physical properties of the plating layer.

It is an object of the present invention to provide a method and an apparatus for performing thick plating with good quality of a plating film even when plating is performed without requiring uniform finishing by mechanical polishing or the like.

[0021]

Means for Solving the Problems The present inventors investigated a plating layer which was thickly plated using a copper sulfate plating bath, and found that a plating method using a copper cyanide plating bath conventionally used for an underlying strike. We studied whether or not it could be applied. As a result, it was confirmed that a good-quality thick plating layer could be obtained by polishing the plating surface, and the present invention was completed. The gist of the present invention resides in a plating method for a retarder cylindrical member described below and a plating apparatus shown in FIG.

A positive electrode 15 is provided at the center of the shaft of the cylindrical member 1, and a friction roller 16 which contacts the inner surface of the cylindrical member.
A plating method for a cylindrical member for an eddy current type reduction gear, wherein the plating is performed while the inner surface of the cylindrical member is being polished while rotating the cylindrical member and the friction roller by using a plating apparatus provided with. It is desirable to use a copper cyanide solution for the plating bath.

An apparatus for plating an inner surface of a cylindrical member of a rotor mounted on an eddy current type reduction gear, wherein a plating tank 22
A support 19 for suspending a cylindrical positive electrode 15 disposed in a cylindrical shape is provided at the center of the support arm, and a support arm extending from the support is provided.
A friction roller 16 supported by a bearing 25 fixed to the plating tank 22 in a water-sealing manner is provided, and a support 17 for holding a cylindrical member 1 of a rotor to be plated is provided inside a column 19. A plating apparatus for a cylindrical member for an eddy current type reduction gear provided with a rotating shaft 20 that supports a rotating arm 18.

The plating thickness targeted by the present invention is 100 to 5
00 μm.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION When a braking test is performed on a cylindrical member of a retarder plated using a copper sulfate plating bath, a plating layer may peel off, crack, or generate pit defects. The inventors investigated these and found the following.

Stripping of plating layer: A brightener containing sulfur is added to the copper sulfate plating bath in order to smooth the surface of the plating layer. Since this sulfur is eutectoid in the plating layer, when the cylindrical member is exposed to a high temperature, it diffuses and concentrates on the interface, and the plating layer peels off.

Cracking of plating layer: A plating layer plated in a plating bath to which a brightening agent has been added has a tensile elongation reduced to about 1/3 as compared with a plating layer to which no plating agent has been added. Cracks occur due to expansion and contraction due to switching.

Pit defects: Since the copper plating layer is soft and easily damaged, a protective film such as a nickel-phosphorus alloy is coated on this layer. However, when the mechanical polishing of the plated surface is performed as shown in (G) of the above process, abrasive grains may remain on the plated surface, and when these abrasive grains cover the protective film, they become pit defects.

Based on these findings, considering the use of a copper cyanide plating bath which has been used in the underground strike treatment, a study was conducted on the copper cyanide plating bath, and the advantages and disadvantages as described below were obtained. I have found that there is. As a result, if the disadvantage of (6) is solved, it is thought that it can be applied to thick plating by extending the processing time, and the research on the method was conducted.

Advantages: (1) Variations in plating thickness due to fluctuations in current density are small, (2) Steel material is not corroded due to the alkaline bath, (3) The size of precipitated crystal grains is fine, (4) It can be plated directly on steel and has good adhesion.

Disadvantages: (5) The plating rate is as low as 10 μm / hour, (6) When thick plating is performed, copper deposits on the plating surface in the form of bumps, and (7) The current is alternated with (+) and (−). Therefore, time loss is large.

In order to prevent the formation of bumps, a brightener may be added. However, the brightener may have the above-described defects (peeling of the plating layer, decrease in tensile elongation), A method of mechanical removal was considered.

JIS SCM415 alloy steel (0.1% C-0.5% Mo-0.05%
V) was prepared, and plating was performed while polishing with a nylon brush in the following plating bath and plating conditions.

Plating bath Cuprous cyanide: 80 g / liter, sodium cyanide: 100 g / liter, sodium carbonate: 30 g / liter, sodium hydroxide: necessary amount for adjusting basicity, analytical composition copper: 50 g / l, same as above. Free cyanide: 10 g / l, plating conditions pH: 12, bath temperature: 50 ° C, current density: 3 A / dm ² , treatment time: 8 hours.

As a result of examining the obtained plating layers, (1) the plating surface is smooth and some of them have a mirror surface.

(2) A dense structure without internal defects.

(3) The performances of the above (1) and (2) can be obtained without alternating the current.

(4) The current density is increased from 1 A / dm ² to 4 A / dm ²
Can be increased up to ² .

From these results, a plating method using a rotary friction method was developed as a method for plating the inner surface of the cylindrical member of the retarder with a copper cyanide bath.

FIG. 1 is a view showing an example of the plating apparatus of the present invention, wherein (a) is a plan view and (b) is a sectional view taken along the line AA of (a).

The cylindrical member 1 of the rotor has its outer peripheral portion supported by three holders 17 and is held so as to be rotatable by a rotating shaft 20 and a large gear 21 penetrating through a rotating arm 18 and a support column 19. . Then, in order to use the cylindrical member as a negative electrode during plating, one end of the rotating shaft is electrically connected (not shown).

The column 19 is a cylinder and is fixed to the plating tank 22. A rotating shaft 20 supported by a bearing 23 penetrates through the inside of the support column, and an arm 24 for suspending the positive electrode 15 and a support arm 25 for supporting the friction roller 16 are attached to the outer periphery thereof. It is desirable that the column be made of an electrically insulating material such as Teflon (trade name) in order to insulate the supporting member between the positive electrode and the cylindrical member.

The friction roller 16 is a roller having nylon (trade name) fiber implanted on its surface. The friction roller 16 is water-sealed by a support arm 25 attached to a column and a bearing 26 attached to a plating tank 22. It rotates in the direction opposite to the cylindrical member 1. The large gear 21 is rotated by a driving device (not shown).

The positive electrode 15 is a cylinder made of copper, suspended on an arm 24, and electrically connected.

Next, a method for plating the inner surface of the cylindrical member of the retarder rotor using the apparatus shown in FIG. 1 will be described.

As shown in FIG. 1, the cylindrical member 1 is attached to three holders 17, and the center of the rotating arm 18 is attached to a rotating shaft 20 provided in a plating tank 22. Plating tank
On 22, a positive electrode 15 and a friction roller 16 are arranged,
The cylindrical member 1 and the positive electrode 15 are electrically connected via a plating bath. Large gear 21 provided at the bottom of plating tank 22
By rotating the cylindrical member 1 and the friction roller 16
And rotate in the opposite direction.

Since the positive electrode copper is deposited on the inner surface while rotating the cylindrical member, even if there is eccentricity,
It can be plated with a uniform thickness. Further, since the friction roller 16 is rotated while being in contact with the inner surface of the cylindrical member 1, the copper deposited in the form of a knob is polished and removed, so that the plated surface can be smoothed.

By rotating the cylindrical member and plating the inner surface of the cylindrical member with a friction roller, a plated layer having a uniform thickness and a fine structure can be obtained. Need not be mechanically polished.

[0049]

EXAMPLE A cylindrical member having an inner diameter of 400 mm, a width of 70 mm, and a diameter of an outer peripheral portion of a fin of 450 mm was prepared, and a rotary plating apparatus of the present invention (one cylindrical member in FIG. The plating was carried out using a device capable of charging the same.
Further, for comparison, an experiment was conducted under the same plating conditions by plating only the plating bath and by swinging the cylindrical member up and down.

Plating bath Cuprous cyanide: 80 g / liter, sodium cyanide: 100 g / liter, sodium carbonate: 30 g / liter, sodium hydroxide: necessary amount for basicity adjustment Analytical composition Copper: 50 g / l, same as above. Free cyanide: 10 g / l, plating conditions pH: 12, bath temperature: 50 ° C, current density: 3 A / dm ² , treatment time: 8 hours.

The plating thickness was measured after plating, and a nickel layer having a thickness of 15 μm was further electroplated as a protective film on the plating layer using a Watt bath (bath temperature 50 ° C., current density 5 A / dm. After forming according to ² ), a heat cycle test was performed. The results are shown in Table 1.

[0052]

[Table 1]

The plating thickness was measured with an electromagnetic film thickness meter. As shown in FIG. 3, the measurement position is such that the inner peripheral portion of the cylindrical member is divided into eight equal parts, a position 10 mm (X) in the axial direction from the end face, 35 m
There are a total of 24 locations: the m position (Y) and the 60 mm position (Z). Table 1
In the above, the variation in the plating thickness "circumferential direction" means the maximum plating thickness and the minimum plating thickness at the positions of (X), (Y) and (Z) divided into eight equal parts. "Axial direction" means the difference (8 points) between the maximum thickness and the minimum thickness of (X), (Y) and (Z) at each of the eight equally divided positions. Indicates the maximum value.

In the heat cycle test, the test specimen was charged into a heating furnace, and the temperature was raised from 100 ° C. to 600 ° C. in 5 minutes, and the temperature was raised from 600 ° C. to 1 ° C.
A heat cycle was given to cool to 00 ° C. in 10 minutes. Then, it was taken out of the furnace every 1000 cycles, and the occurrence of cracks and peeling on the plated surface was observed. The results are shown in Table 1.

Since the cylindrical members of the test pieces Nos. 1, 2 and 3 of the invention were obtained by using the rotary plating method, the variation in the plating thickness was 5 μm or less in the circumferential direction and 15 μm in the axial direction.
μm or less, which is good. After 5000 thermal cycle tests, neither cracking nor peeling of the plating layer was observed.

On the other hand, since the cylindrical members of the test pieces Nos. 4, 5 and 6 of the comparative examples were obtained by using the oscillating plating method, the variation in the plating thickness was 34 to 197 μm in the circumferential direction.
m, 173 to 258 μm in the axial direction, with large variations. In the thermal cycle test, cracks were observed after 1000 or 2000 times, and peeling was observed after 3000 or 4000 times. Since the cylindrical members of specimens Nos. 7 and 8 were obtained by using the stirring plating method, the plating thickness varied greatly in the circumferential direction from 121 to 226 µm and in the axial direction from 214 to 278 µm. Also, in the heat cycle test, cracks occur 1000 times,
Peeling was observed at 3000 times.

[0057]

The plating method of the present invention, in which the plated surface is polished by a rotating friction roller, enables thick plating using a copper cyanide plating bath and eliminates the need for masking of the non-plated surface. Also, without the need to add brighteners,
It is possible to obtain a uniform, dense, and well-structured plating layer. For this reason, the mechanical polishing conventionally performed becomes unnecessary.

The retarder in which the inner surface of the cylindrical member is plated by using the plating apparatus and the plating method of the present invention can improve the braking performance and prevent the plating layer from being deteriorated (crack or peeling) even by repeated braking. , With excellent durability.

[Brief description of the drawings]

FIG. 1 is a view showing one example of a plating apparatus of the present invention;
(a) is a plan view, and (b) is an AA cross-sectional view of (a).

FIG. 2 is a longitudinal sectional view showing an example of a retarder using a permanent magnet.

3A and 3B are diagrams showing a cylindrical member of the retarder, wherein FIG. 3A is a longitudinal sectional view, and FIG. 3B is a plan view.

[Brief description of reference numerals]

 1. 1. cylindrical member Spokes 3. Disk 4. Fins 5. Bracket 6. Rotation axis 7. 7. permanent magnet Support ring 9. Pole piece 10． Casing 11． Guide rod 12． Drive unit 13. Piston rod 14. Plated surface 15. Positive electrode 16. Friction roller 17． Holder 18. Rotating arm 19. Prop 20. Rotary axis 21. Large gear 22. Plating tank 23. Bearing 24. Arm 25. Support arm 26. Bearing 27. Gear 28. Plating bath Rotor S. Stator X, Y, Z. Plating thickness measurement position

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shoka Ishida 5-1-1109 Shimaya, Konohana-ku, Osaka-shi 1-12-26 Kashiwada Nishi, Higashiosaka-shi Teikoku Aeon Co., Ltd.

Claims (3)

[Claims] 1. A method of plating an inner surface of a cylindrical member of a rotor mounted on an eddy current type speed reducer, wherein a positive electrode is provided at a central portion of a shaft of the cylindrical member, and the inner surface of the cylindrical member is in contact with the positive electrode. Using a device provided with a friction roller that rotates
A plating method for a cylindrical member for an eddy current type reduction gear, wherein a plating surface is polished with a friction roller and plating is performed while rotating the cylindrical member. 2. The method for plating a cylindrical member for an eddy current type reduction gear according to claim 1, wherein a copper cyanide solution is used as a plating bath. 3. An apparatus for plating an inner surface of a cylindrical member of a rotor mounted on an eddy current type reduction gear, wherein a cylindrical positive electrode disposed in a cylindrical shape at a center of a plating tank is suspended. A strut is provided, a friction roller supported by a support arm extending from the strut and a bearing water-sealed to the plating tank is provided, and a cylindrical member of a rotor to be plated is held inside the strut. A plating device for a cylindrical member for an eddy current type reduction gear, comprising: a rotating shaft that supports a rotating arm of a holding tool to be provided.