JP3291154B2 - Method of forming inner peripheral surface of cylindrical portion and inner plating engine cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an inner peripheral surface of a cylindrical portion of a work having a cylindrical portion, the inner peripheral surface of the cylindrical portion being plated by plating. The present invention relates to an internal plating engine cylinder in which a plating film is formed on the inner peripheral surface of a cylinder by this method.

[0002]

2. Description of the Related Art Conventionally, as a method of forming an inner peripheral surface of a cylindrical portion of a work having a cylindrical portion, an inner diameter of the cylindrical portion is formed substantially uniformly in an axial direction, and the inner peripheral surface is formed on the inner peripheral surface. After applying a plating process to form a plating film with a substantially uniform thickness,
By finishing the surface of the plating film, the inner diameter of the cylindrical portion is uniformly finished in the axial direction. As a specific example, in the case of an engine cylinder block, the inner diameter of the cylinder is processed substantially uniformly in the axial direction, and after plating the inner peripheral surface of the cylinder with nickel or the like, the inner peripheral surface of the cylinder is processed. Honing is performed so that the inner diameter of the cylinder is made uniform in the axial direction to secure a piston sliding surface.

Incidentally, such plating methods include:
A stationary bath plating technique in which a cylinder block is immersed in a bath containing a processing solution, and an electrode is positioned in the cylinder, and a voltage is applied between the cylinder and the electrode to perform plating. While applying the plating liquid while supplying the processing liquid into the cylinder and flowing the processing liquid in the cylinder while the cylinder opening is closed, plating is performed by applying a voltage between the cylinder and the electrode. A so-called high-speed plating technique is known.

[0004]

By the way, on the inner peripheral surface of the cylinder formed as described above, the plating film is simply formed to have a substantially uniform thickness from the crankcase side of the cylinder to the combustion chamber side. Therefore, there is still room for improvement in properly maintaining the operating state of the engine.

[0005] In other words, the wear characteristics of the inner peripheral surface of the cylinder are such that the wear on the side where the thermal load is large, that is, on the side near the cylinder head is severe, so that the deterioration of the cylinder in the combustion chamber side as compared to the crankcase side is larger. It is easier to progress.

Further, the plating material is, for example, nickel,
When the cylinder base material is an aluminum alloy, the coefficient of linear expansion of the cylinder base material is larger than that of the plated layer, and therefore thermal stress acts to expand the plated layer outward during operation of the engine. On the other hand, when the plated material has a larger linear expansion coefficient than the cylinder base material, conversely, thermal stress acts to compress the plated layer from outside during operation of the engine. That is, in each case, driving,
The thermal cycle is intermittently effected by repeated heat cycles due to the stoppage, which may cause cracks on the plating surface and cause the plating layer to peel off due to long-term operation of the engine. It is likely to occur on the head side.

Further, during operation of the engine, the inner diameter of the inner circumference of the cylinder increases toward the cylinder head due to thermal distortion.
For this reason, if the cylinder inner diameter is made constant in the axial direction, the inner diameter on the cylinder head side increases during operation of the engine. In particular, since the blow-through is large, if the tension of the piston ring is set in accordance with the thermal expansion of the cylinder head, the tension on the crankcase side further increases in the axial direction of the cylinder during operation. There is also a problem that abrasion of the tire increases.

Therefore, in order to maintain an appropriate operating state of the engine for a longer period of time, the inner peripheral surface of the cylinder is formed in consideration of such wear characteristics of the inner peripheral surface of the cylinder.
Accordingly, it is necessary to improve durability of the inner peripheral surface of the cylinder by coping with uneven plating wear or thermal stress as described above.

The present invention solves the above-mentioned technical problem, and forms a plating film having a thickness suitable for a work while securing the inner diameter of the cylindrical portion uniformly in the axial direction. An object of the present invention is to provide a method for forming an inner peripheral surface of an optimal cylindrical portion, and to provide a high quality inner plating engine cylinder by applying the method to the formation of an inner peripheral surface of an engine cylinder.

[0010]

According to a first aspect of the present invention, there is provided a method for forming an inner peripheral surface of a cylindrical portion, wherein the inner diameter of the cylindrical portion of a work having the cylindrical portion is changed from one side in the axial direction of the cylindrical portion to the other side. The electrode is inserted into the cylindrical portion, and a voltage is applied between the electrode and the workpiece in a state where the space between the inner peripheral surface of the cylindrical portion and the electrode is filled with the processing liquid. After the plating process is performed on the inner peripheral surface of the cylindrical portion, the finishing process is performed so that the surface of the plating film formed on the inner peripheral surface of the cylindrical portion is substantially parallel to the central axis of the cylindrical portion. It is like that.

According to a second aspect of the present invention, in the method of forming the inner peripheral surface of the first aspect, the distance between the inner peripheral surface and the electrode increases as the inner diameter of the cylindrical portion increases. Is reduced so that the plating treatment is performed.

According to a third aspect of the present invention, in the method of forming an inner peripheral surface of a cylindrical portion according to the first or second aspect, the work is placed on a work supporting portion. A path for flowing the processing liquid inside the cylindrical portion is formed by projecting an electrode also serving as a flow path component member protruding from the support portion into the cylindrical portion of the work, and in this state, the path is formed in the path. The plating liquid is supplied to the inner peripheral surface of the cylindrical portion by supplying a processing liquid.

According to a fourth aspect of the present invention, there is provided a method for forming an inner peripheral surface of a cylindrical portion according to any one of the first to third aspects. A method of forming an inner circumferential surface of a cylinder of a cylinder block of an engine, wherein the inner diameter of the cylinder is formed so as to expand from the crankcase side of the cylinder toward the combustion chamber, and the plating process is performed. It was made.

According to a fifth aspect of the present invention, there is provided a method of forming an inner peripheral surface of a cylindrical portion according to any one of the first to third aspects. The method is a method of forming an inner circumferential surface of a cylinder of a cylinder block of an engine, wherein the inner diameter of the cylinder is formed so as to expand from the combustion chamber side of the cylinder toward the crankcase side, and the plating process is performed. It was made.

According to a sixth aspect of the present invention, there is provided a method for forming an inner peripheral surface of a cylindrical portion according to any one of the first to third aspects. The method is a method of forming an inner peripheral surface of a cylinder of a cylinder block of an engine, wherein the inner diameter of the cylinder is formed so as to expand from a substantially central portion in the axial direction of the cylinder toward a combustion chamber and a crankcase. The above plating process is performed.

According to a seventh aspect of the present invention, there is provided an engine cylinder having an inner peripheral surface formed by the method for forming an inner peripheral surface of a cylindrical portion according to the fourth aspect, wherein a plating film on the inner peripheral surface of the cylinder is provided. Is formed so that the thickness gradually increases from the crankcase side of the cylinder toward the combustion chamber, and the surface of the plating film is parallel to the central axis of the cylinder.

According to an eighth aspect of the present invention, there is provided an engine cylinder having an inner peripheral surface formed by the method for forming an inner peripheral surface of a cylindrical portion according to the fifth aspect, wherein a plating film on the inner peripheral surface of the cylinder is provided. Is formed so that the thickness gradually increases from the combustion chamber side of the cylinder toward the crankcase side, and the surface of the plating film is parallel to the central axis of the cylinder.

According to a ninth aspect of the present invention, there is provided an engine cylinder having an inner peripheral surface formed by the method for forming an inner peripheral surface of a cylindrical portion according to the sixth aspect, wherein a plating film on the inner peripheral surface of the cylinder is formed. Is formed so that the thickness gradually increases from the substantially central portion in the axial direction of the cylinder toward the combustion chamber and the crankcase, and the surface of the plating film is parallel to the central axis of the cylinder.

[0019]

According to the method for forming the inner peripheral surface of the cylindrical portion according to the first aspect, a plating film is formed on the inner peripheral surface of the cylindrical portion whose inner diameter changes in the axial direction. Since it is processed so as to be substantially parallel to the central axis of the cylindrical part,
While the diameter of the inner peripheral surface of the plating film is formed uniformly in the axial direction, the thickness of the plating film is increased at the portion where the inner diameter of the cylindrical portion is large, and conversely, at the portion where the inner diameter of the cylindrical portion is small. The thickness can be reduced.

According to the method for forming the inner peripheral surface of the cylindrical portion according to the second aspect, the deposition of the plating substance is effectively promoted at a portion having a large inner diameter on the inner peripheral surface of the cylindrical portion, and the inner diameter is reduced. The thickness of the plating film at a large portion can be effectively increased.

According to the method for forming the inner peripheral surface of the cylindrical portion according to the third aspect of the present invention, the plating liquid in the processing liquid between the electrode and the inner peripheral surface of the cylindrical portion is caused by flowing the processing liquid. Since the concentration is maintained at a high concentration, the deposition of the plating substance is effectively promoted, and the inner peripheral surface of the cylindrical portion as described above is efficiently formed.

According to the method for forming the inner peripheral surface of the cylindrical portion according to the fourth aspect, in the cylinder of the engine, the thickness of the plating film on the combustion chamber side where the abrasion or the peeling of the plating film is likely to occur is increased. However, it is possible to secure the piston sliding surface by making the inner diameter of the cylinder on which the plating film is formed uniform in the axial direction.

According to the method for forming the inner peripheral surface of the cylindrical portion according to the fifth aspect, the plating film on the crankcase side where the plating film is liable to wear due to the tension of the piston ring in the engine cylinder. While the thickness is increased, the inner diameter of the cylinder on which the plating film is formed is made uniform in the axial direction, so that the piston sliding surface can be secured.

According to the method for forming the inner peripheral surface of the cylindrical portion according to the sixth aspect of the present invention, the inner circumferential surface of the engine is caused by the abrasion in the cylinder of the engine or the tension of the piston ring where the plating film is apt to peel off. While increasing the thickness of the plating film on the crankcase side where wear tends to occur, it is possible to secure the piston sliding surface by making the inner diameter of the cylinder on which the plating film is formed uniform in the axial direction.

According to the internal plating engine cylinder of the present invention, since the thickness of the plating film on the combustion chamber side is large, a decrease in the durability of the plating film due to wear on the combustion chamber side is suppressed. You.

According to the internal plating engine cylinder of the present invention, since the thickness of the plating film on the crankcase side is increased, the durability due to the wear of the plating film on the crankcase side caused by the tension force of the piston ring. Is suppressed.

According to the internal plating engine cylinder of the ninth aspect, a decrease in durability due to abrasion of the plating film on the crankcase side due to the tension of the piston ring is suppressed, and wear on the combustion chamber side is suppressed. This suppresses a decrease in durability of the plating film due to the above.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the inner peripheral surface forming method of the present invention will be described with reference to the drawings.

In this embodiment, a piston sliding surface is formed by applying plating to the inner peripheral surface of the cylinder of the cylinder block of the engine and then performing honing to the inner peripheral surface of the cylinder.

As an apparatus for plating the inner peripheral surface of the cylinder, for example, a plating apparatus as shown in FIG. 1 is applied. This plating apparatus is an apparatus for performing so-called high-speed plating, and has a configuration described below.

That is, the plating apparatus 10 shown in FIG.
A is provided with a support block 11 as a work support portion, and a cylinder block 1 as a work is supported on the support block 11 to support a lower opening of the cylinder 1a (that is, an opening on the combustion chamber side). Block 11 blocks it.

More specifically, a cylinder block 1 of a four-cycle engine in which a cylinder component having a cylinder 1a and a skirt-shaped crankcase portion are integrally formed.
Is supported by the support block 11 in a state where the cylinder 1a is turned upside down as compared with a state when the cylinder 1a is mounted on a vehicle.
The opening on the side of the combustion chamber is closed by the support block 11.

As shown in FIG. 2, the cylinder block 1 used in this embodiment has a tapered inner peripheral surface of the cylinder 1a. That is, cylinder 1
a has a predetermined angle (inclination angle α) with respect to the vertical axis.
1), whereby the cylinder 1a is formed to have a truncated cone shape that expands from the crankcase side to the combustion chamber side (from above to below in FIG. 2).

The inclination angle α1 is determined by the cylinder 1a
It is set so that a desired thickness change can be given to the plating film formed on the substrate. That is,
When the change in the thickness of the plating film is increased, the inclination is increased.

As shown in FIG. 1, a processing liquid lead-out passage 12 is formed in the support block 11 at a position below a cylinder component of the cylinder block 1.
On the upper surface of the support block 11, the processing liquid outlet passage 12 is provided at a position corresponding to the cylinder 1a of the cylinder block 1.
There is provided an opening 11a that communicates with the opening. When the cylinder block 1 is supported on the support block 11 as described above, the cylinder 1
The opening 11a is aligned with the opening 11a. When the cylinder block 1 is supported on the support block 11, the cylinder block 1 is electrically insulated from each other and is sealed so that the processing liquid does not leak outside.

Further, the plating apparatus 10A is provided with electrodes 13 which also serve as flow path components at positions corresponding to the cylinders 1a of the cylinder block 1. Electrode 1
3 is formed in a cylindrical shape whose diameter is uniform in the axial direction,
The processing liquid outlet passage 12 is attached to the support block 11 via a holder 14 attached to the bottom of the processing liquid outlet passage 12, and penetrates through the processing liquid outlet passage 12 to form the opening 11a.
Projecting upwards.

When the cylinder block 1 is supported on the support block 11, the electrode 13 protrudes into the cylinder 1a of the cylinder block 1 and its upper end reaches near the upper end of the cylinder 1a. A predetermined gap is maintained between the surface and the inner peripheral surface of the cylinder. Thereby, inside and outside of the electrode 13 in the cylinder 1a of the cylinder block 1, channels 15 and 16 communicating with each other in the upper portion are formed, and the outside channel 16 communicates with the processing liquid outlet passage 12. It has become.

A through-hole is formed in the holder 14, and the through-hole and the through-hole formed in the support block 11 allow the processing liquid introduction passage 17 communicating with the flow path 15 inside the electrode 13. Are formed.

On the other hand, as described above, the plating apparatus 10A
In the upper part of the cylinder block 1 supported by the upper part, an upper opening which is an opening of the cylinder 1a on the side opposite to the support block 11 side (that is, an opening on the crankcase side).
The seal jig 18 for closing the space is mounted.

The sealing jig 18 includes a plate member 19 pressed against the upper portion of the cylinder block 1, a columnar member 20 protruding below the plate member 19, and a lower end of the columnar member 20 provided with an elastic material such as rubber. The plate member 19 is pressed against the upper part of the cylinder block 1 so that the columnar member 20 is connected to the cylinder 1a as shown in FIG.
To the plate member 19 in this state.
Is expanded, the outer peripheral portion of the plate member 19 is pressed against the inner peripheral surface of the cylinder 1a, and the opening of the cylinder 1a on the crankcase side is sealed.

As shown in FIG. 1, the processing liquid supply / discharge system for the plating apparatus 10 is such that a processing liquid is supplied from a processing liquid storage tank 22 to a pump 23 and valves 24 and 2.
The processing liquid is fed into the processing liquid introduction passage 17 through a processing liquid supply pipe 26 provided with the processing liquid 5, passes through the flow paths 15, 16, and then flows from the processing liquid discharge passage 12 through a processing liquid recovery pipe 27 to a processing liquid storage tank. 22.

The electrical system for the plating apparatus 10A is such that the seal jig 18 and the support block 11 are each connected to a current regulator 28, and the current regulator 28 is connected to an AC power supply 30 via an AC / DC converter 29. To the electrode 13 via the support block 11.
It is configured such that a voltage is applied between the motor and the cylinder block 1.

In the plating apparatus 10A, in the state shown in FIG. 1 in which the cylinder block 1 is supported by the support block 11, the processing liquid is supplied and circulated by the supply / discharge system while the cylinder block 1 is supplied to the electrode 13. The energization is performed, whereby plating is applied to the inner peripheral surface of the cylinder 1a of the cylinder block 1.

Specifically, the processing liquid supplied to the processing liquid introduction passage 17 passes through the flow path 15 inside the electrode 13 as shown by the arrow in FIG. Channel 16 between the outer surface of electrode 13 and the inner peripheral surface of cylinder 1a
Flows to Further, after flowing into the processing liquid outlet passage 12 through the opening 11a, the liquid is returned to the processing liquid storage tank 22. Then, the processing liquid is circulated in this manner, and while the processing liquid is caused to flow along the inner peripheral surface of the cylinder 1a of the cylinder block 1, a current is applied between the electrode 13 and the cylinder 1a, thereby causing the cylinder 1a to flow. 2, a plating film P having a substantially uniform thickness in the axial direction of the cylinder 1a is formed as shown in FIG.
In this case, since the plating process is performed in a state where the inclination angle α1 is small and the distance between the electrode and the inner peripheral surface of the cylinder is large, the inner peripheral surface of the cylinder and the electrode are connected as in the fourth to sixth embodiments described later. Does not change significantly, and therefore the plating deposition rate is substantially uniform.

When the plating film P is formed on the inner peripheral surface of the cylinder 1a by the plating apparatus 10A in this way, the cylinder block 1 is removed from the plating apparatus 10A and the cylinder 1a is washed with water. , Cylinder 1
A predetermined honing finish is applied to a.

Although not shown in detail, the honing finishing process moves the inside of the cylinder 1a along the central axis of the cylinder 1a while rotating a column-shaped honing head 31 (see FIG. 2) having a constant diameter R. This is done by:

As a result, the plating film P is shaved and finished so that the inner diameter of the cylinder 1a becomes uniform in the axial direction, and the thickness gradually increases from the crankcase side to the combustion chamber side as shown in FIG. And its surface is the cylinder 1a
The inner peripheral surface of the cylinder on which the plating film Pa is formed parallel to the central axis is obtained.

According to the cylinder inner peripheral surface obtained in this manner, as described above, the thickness of the plating film is
Since the heat load gradually increases from the crankcase side to the combustion chamber side, the heat load is large, and therefore the deterioration of the plating film of the cylinder 1a on the combustion chamber side where the wear is severe can be suppressed. In addition, since the surface of the film is parallel to the central axis of the cylinder 1a, the sliding surface of the piston is appropriately secured. Therefore, the durability of the plating film of the cylinder 1a is more improved as compared with a conventional cylinder block in which a plating film having a substantially constant thickness is formed from the crankcase side to the combustion chamber side. This makes it possible to maintain the operating state of the engine properly over a long period of time.

As a second embodiment of such an inner peripheral surface forming method, as shown in FIG. 3, the inner peripheral surface is inclined at a predetermined angle (inclination angle α2) with respect to a vertical axis. It is also effective to use a cylinder block 2 having a cylinder 2a that is formed so as to expand toward the crankcase side from the combustion chamber side.

In this case, as shown in FIG. 3, after a substantially uniform plating film P is formed on the inner peripheral surface of the cylinder 2a, a cylindrical honing head 3 having a constant diameter R is formed.
As a result of the honing finishing performed by the step 1, the inner peripheral surface of the completed cylinder 2a gradually increases in thickness from the combustion chamber side to the crankcase side as shown in FIG. A plating film Pb parallel to the axis can be formed.

According to the plating film Pa, since the thickness gradually increases from the combustion chamber side of the cylinder 2a toward the crankcase side, the deterioration of the plating film of the cylinder 2a on the crankcase side can be effectively suppressed. it can. Therefore, the tension of the piston ring is set in accordance with the thermal expansion of the cylinder head, and even if the tension of the piston ring on the crankcase increases during the operation of the engine, even if the situation arises, The durability of the plating film on the side can be effectively increased.

Further, as a third embodiment of the method of forming the inner peripheral surface, as shown in FIG. 4, the inner peripheral surface of the cylinder extends vertically from the substantially central portion in the axial direction to the crankcase side and the combustion chamber side, respectively. At a predetermined angle (inclination angle α3 toward the combustion chamber side, inclination angle α toward the crankcase side)
4), the cylinder block 3 having the cylinder 3a which is formed so as to extend forward from a substantially central portion in the axial direction toward the combustion chamber and the crankcase.
It is also effective to use as a work.

In this case, as shown in FIG. 4, after a substantially uniform plating film P is formed on the inner peripheral surface of the cylinder 3a, a cylindrical honing head 3 having a constant diameter R is formed.
As a result of the honing finishing performed by the step 1, the thickness of the inner peripheral surface of the completed cylinder 3a gradually increases from the substantially central portion in the axial direction of the cylinder 3a toward the combustion chamber and the crankcase as shown in FIG. In addition, a plating film Pc whose surface is parallel to the central axis of the cylinder 3a can be formed.

According to the plating film Pc, the thickness gradually increases from the axial center portion of the cylinder 3a toward the combustion chamber side and the crankcase side, so that the thickness of the cylinder 3a on both the combustion chamber side and the crankcase side is increased. Deterioration of the plating film can be effectively suppressed. Therefore, the effect of both the plating films Pc and Pb, that is, the thermal load or thermal stress, is large, and therefore, the deterioration of the plating film on the combustion chamber side where wear is severe and the crank caused by the increase in the tension force of the piston ring. Both effects such as suppression of deterioration of the plating film on the case side can be obtained.

Next, fourth to sixth embodiments of the method for forming the inner peripheral surface, which do not constitute the present invention, will be described below.

The inner peripheral surface forming method of the fourth embodiment is a method of forming the inner peripheral surface of the cylinder by plating the inner peripheral surface of the cylinder 1a using the cylinder block 1 as a work. Although it is the same as the first embodiment, it is different from the method of forming the inner peripheral surface of the first embodiment in that honing is not basically performed.

The plating in the inner peripheral surface forming method of the fourth embodiment is performed by a plating apparatus 10B provided with an electrode 33 as shown in FIG. 8 instead of the electrode 13 of the plating apparatus 10A. The configuration of the plating apparatus 10B other than the electrodes is the same as that of the above-described plating apparatus 10A, and will be described using the same reference numerals.

The electrode 33 has a tapered outer peripheral surface. Specifically, as shown in the figure, the outer peripheral surface is inclined at a predetermined angle (inclination angle β1) with respect to the vertical axis, whereby the whole is
A is formed in a truncated cone shape that gradually becomes thicker from the crankcase side to the combustion chamber side.

Here, the inclination angle β1 of the electrode 33 is
The inclination angle α1 of the cylinder 1a in the cylinder block 1 is sufficiently larger than that of the cylinder block 1 so that the flow path 16 formed between the inner peripheral surface of the cylinder 1a and the outer peripheral surface of the electrode 33 is formed from above to below. That is, the cylinder 1a is set so as to gradually narrow from the crankcase side to the combustion chamber side.

By performing plating on the cylinder 1a by the plating apparatus 10B, the thickness of the plating film gradually increases from the crankcase side to the combustion chamber side, as in the first embodiment. A plating film having a surface parallel to the central axis of the cylinder 1a can be formed on the cylinder 1a.

That is, in an apparatus that performs plating by flowing a processing liquid, the closer the distance between the electrode and the processing surface is, the more the plating is performed.
The current density during the treatment is increased, and the deposition of the plating substance is promoted. Also, the higher the flow rate of the processing liquid, the higher the concentration of the plating substance in the processing liquid existing between the electrode and the processing surface, thereby promoting the deposition of the plating substance. Therefore, in the plating apparatus 10B in which the flow path 16 narrows from the crankcase side to the combustion chamber side, the distance between the cylinder 1a and the electrode 33 approaches from the crankcase side to the combustion chamber side, This also increases the flow velocity of the processing liquid flowing through the flow path 16 from the crankcase side to the combustion chamber side,
As described above, the effect of accelerating the deposition of the plating substance is effectively exerted. As a result, the amount of the plating substance deposited on the cylinder 1a increases from the crankcase side to the combustion chamber side, and the thickness of the plating film increases. This gradually increases from the crankcase side of the cylinder 1a toward the combustion chamber.

Accordingly, the cylinder 1a of the cylinder block 1, which is formed in the shape of a truncated cone extending from the crankcase side toward the combustion chamber side, is plated as described above. 1a
The inclination angle α1 of the inner peripheral surface of the cylinder 1a, the inclination angle β1 of the electrode 33, the electrode 33
The thickness of the cylinder 1a gradually increases from the crankcase side to the combustion chamber side, and the surface of the plating film is parallel to the center axis of the cylinder 1a, or It is possible to form a plating film Pa (see FIG. 5) which is in a state close to this. Then, the surface of the plating film is made parallel to the central axis of the cylinder 1a by further performing honing processing as necessary.

Incidentally, the plating apparatus 1 of the fourth embodiment described above.
At 0B, the thickness of the plating film can also be gradually increased from the combustion chamber side to the crankcase side by configuring the electrode 33 as shown in FIG.

The diameter of the electrode 33 is made uniform in the axial direction, or the outer peripheral surface of the electrode 33 is
By tilting at the same angle as the tilt angle α1 of a, the whole is formed in a truncated cone shape that gradually becomes thicker from above to below. In the electrode 33, a large number of communication paths 35 communicating the flow path 15 and the flow path 16 are formed in the circumferential direction and the axial direction of the electrode 33.

With this electrode 33, the flow path 16 does not narrow from the crankcase side of the cylinder 1 a toward the combustion chamber, but the processing liquid flows into the flow path 16 via the upper end portion of the electrode 33. The flow path 16 through the communication path 35
As a result, the flow speed of the processing liquid is increased from the crankcase side toward the combustion chamber side. Therefore, the thickness of the plating film on the inner peripheral surface of the cylinder gradually increases from the crankcase side to the combustion chamber side, whereby the plating film Pa can be obtained.

Next, a fifth embodiment of the inner peripheral surface forming method will be described.

The inner peripheral surface forming method of the fifth embodiment is a method of forming the inner peripheral surface of the cylinder by plating the inner peripheral surface of the cylinder 2a using the cylinder block 2 as a work. The second embodiment is the same as the second embodiment, but differs from the second embodiment in that no honing is performed.

The plating process in the inner peripheral surface forming method of the fifth embodiment is performed by a plating apparatus 10C provided with an electrode 43 as shown in FIG. 10 instead of the electrode 13 of the plating apparatus 10A. In addition, the plating treatment apparatus 10C
Since the configuration other than the above-mentioned electrode is the same as that of the above-mentioned plating apparatus 10A, it will be described using the same reference numerals.

The electrode 43 has a tapered outer peripheral surface. Specifically, as shown in the figure, the outer peripheral surface is inclined at a predetermined angle (inclination angle β2) with respect to the vertical axis, whereby the whole is
A is formed in a truncated cone shape that gradually becomes thicker from the combustion chamber side toward the crankcase side.

Here, the inclination angle β2 of the electrode 43 is
The inclination angle α2 of the cylinder 2a in the cylinder block 2 is larger than the inclination angle α2 of the cylinder 2a. Is set so as to gradually narrow toward the crankcase side.

The plating apparatus 10 in which the flow passage 16 narrows from the combustion chamber side toward the crankcase side as described above.
In C, the distance between the cylinder 2a and the electrode 43 approaches from the combustion chamber side to the crankcase side, and the flow velocity of the processing liquid flowing through the flow path 16 increases from the combustion chamber side to the crankcase side. Therefore, the deposition amount of the plating substance on the cylinder 2a increases from the combustion chamber side toward the crankcase side, and as a result, the thickness of the plating film gradually increases from the combustion chamber side of the cylinder 2a toward the crankcase side. Will be.

Accordingly, by appropriately setting the inclination angle α2 of the inner peripheral surface of the cylinder 2a, the inclination angle β2 of the electrode 43, the amount of electricity to the electricity 43, the plating time, etc., the crankcase can be moved from the combustion chamber side of the cylinder 2a. The plating film Pb whose thickness gradually increases toward the side and the surface of the plating film is parallel to the central axis of the cylinder 2a (see FIG. 6).
Can be formed.

Incidentally, the plating apparatus 1 of the fifth embodiment described above.
At 0C, the thickness of the plating film can also be gradually increased from the combustion chamber side toward the crankcase side by configuring the electrode 43 as shown in FIG.

The diameter of the electrode 43 is made uniform in the axial direction, or the outer peripheral surface of the electrode 43 is
By being inclined at the same angle as the inclination angle α2 of a, the whole is formed in a truncated cone shape that gradually becomes thicker from below to above. In addition to the flow path 15, the electrode 43 is formed with a flow path 45 that bypasses the flow path 16 at a position lower than a portion facing the inner peripheral surface of the cylinder. A large number of communicating passages 46 are formed in the circumferential direction and the axial direction of the electrode 43.

According to this electrode 43, the flow path 16 does not narrow from the combustion chamber side of the cylinder 2 a toward the crankcase side, but the processing liquid in the flow path 16 flows into the flow path 45 via the communication path 46. The flowing speed of the processing liquid flowing through the flow path 16 decreases from the crankcase side to the combustion chamber side. In other words, in other words, the flow speed of the processing liquid is increased from the combustion chamber side toward the crankcase side. For this reason, the thickness of the plating film on the inner peripheral surface of the cylinder gradually increases from the combustion chamber side toward the crankcase side, whereby the plating film Pb can be obtained.

Next, a sixth embodiment of the inner peripheral surface forming method will be described.

The inner peripheral surface forming method of the sixth embodiment is a method of forming the inner peripheral surface of the cylinder by plating the inner peripheral surface of the cylinder 3a using the cylinder block 3 as a work. The third embodiment is the same as the third embodiment, but differs from the third embodiment in that the honing process is not performed.

The plating process in the inner peripheral surface forming method of the sixth embodiment is performed by a plating apparatus 10D provided with an electrode 53 as shown in FIG. 12, instead of the electrode 13 of the plating apparatus 10A. The plating apparatus 10D
Since the configuration other than the above-mentioned electrode is the same as that of the above-mentioned plating apparatus 10A, it will be described using the same reference numerals.

The outer peripheral surface of the electrode 53 is inclined at a predetermined angle (a downward inclination angle β3 and an upward inclination angle β4) with respect to the vertical axis upward and downward from a substantially central portion in the axial direction. Thereby, the whole is formed in a shape that gradually becomes thicker upward and downward from a substantially central portion in the axial direction.

Here, the relationship between the electrode 53 and the cylinder 3a is such that the inclination angle α3 <the inclination angle β3 and the inclination angle α4 <the inclination angle β4, whereby the inner peripheral surface of the cylinder 3a and the outer peripheral surface of the electrode 53 are formed. Channel 16 formed between
Are set so as to gradually narrow downward and upward from the vertical central portion, that is, from the axial central portion of the cylinder 3a toward the combustion chamber and the crankcase.

In the plating apparatus 10D in which the flow passage 16 narrows from the center toward the combustion chamber and the crankcase, the cylinder 3a and the electrode 53 are separated.
From the central portion toward the combustion chamber and the crankcase, respectively, and the flow velocity of the processing liquid flowing through the flow path 16 increases from the central portion toward the combustion chamber and the crankcase. . Therefore, the deposition amount of the plating substance on the cylinder 3a increases from the central portion toward the combustion chamber and the crankcase, respectively, and the thickness of the plating film increases from the central portion of the cylinder 3a toward the combustion chamber and the crankcase. Respectively.

Accordingly, by appropriately setting the inclination angles α3 and α4 of the inner peripheral surface of the cylinder 3a, the inclination angles β3 and β4 of the electrode 53, the amount of power to the electrode 53, the plating time, and the like, the central portion of the cylinder 3a Thus, a plating film Pc (see FIG. 7) can be formed in which the thickness gradually increases toward the combustion chamber side and the crankcase side, and the surface of the plating film is parallel to the central axis of the cylinder 3a.

Incidentally, the plating apparatus 1 of the sixth embodiment described above.
In 0D, the thickness of the plating film can also be gradually increased from the central portion of the cylinder 3a toward the combustion chamber side and the crankcase side by configuring the electrode 53 as shown in FIG.

The diameter of the electrode 53 is made uniform in the axial direction, or the outer peripheral surface is inclined at the same angle as the inclination angles α3 and α4 of the cylinder 3a with respect to the vertical axis, so that the whole electrode is substantially axially substantially inclined. It is formed in a shape that gradually becomes thicker upward and downward from the central portion. The electrode 53 is provided with a flow path 15a that branches off from the flow path 15 and reaches a substantially central portion in the axial direction of the cylinder 3a.
The communication path 57 that connects the flow path 15a and the flow path 16
3 are formed in a large number in the circumferential and axial directions. further,
A flow path 55 is formed in the electrode 53 so as to bypass the flow path 16 at a position lower than a portion facing the inner circumferential surface of the cylinder,
A communication path 56 that communicates the flow path 55 and the flow path 16 has an electrode 5 at a position higher than the axial center of the cylinder 3a.
3 are formed in a large number in the circumferential and axial directions.

According to the electrode 53, the flow path 16 does not narrow from the center of the cylinder 3 a toward the combustion chamber and the crankcase, but the processing liquid in the flow path 16 passes through the communication path 56 through the communication path 56. 55 to flow path 16
The flow speed of the processing liquid flowing through the flow path 15a decreases from the crankcase side toward the center of the cylinder.
The flow rate of the processing liquid flowing through the flow path 16 increases from the central portion of the cylinder 3a toward the combustion chamber due to the flow of the processing liquid supplied through the communication path 57 into the flow path 16. That is, the flow speed of the processing liquid is
The height increases from the central portion of a toward the combustion chamber side and the crankcase side. Therefore, the thickness of the plating film on the inner peripheral surface of the cylinder gradually increases from the central portion of the cylinder 3a toward the combustion chamber side and the crankcase side, whereby the plating film Pc can be obtained.

As described above, by forming the inner peripheral surface of the cylinder by applying the inner peripheral surface forming method described in the first to sixth embodiments, it is possible to form the inner peripheral surface of the cylinder suitable as the piston sliding surface. Among them, according to the inner peripheral surface forming methods of the fourth to sixth embodiments, the plating film can be formed in a state where the central axis of the cylinder and the surface of the plating film are nearly parallel in the plating treatment, so that the honing finish processing is performed. Thus, the direction of the plating film and the central axis of the cylinder can be easily made parallel. If the center axis of the cylinder is parallel to the surface of the plating film in the plating process, the honing finishing process can be omitted.

In the plating process in the inner peripheral surface forming method of each of the above embodiments, a so-called high-speed plating process is performed. In addition, a plating solution is stored between a cylinder and an electrode. The plating treatment may be performed by a static bath plating method for performing the plating.

FIG. 14 shows an example of an apparatus for performing plating on the inner peripheral surface of a cylinder of a cylinder block by such a static bath plating method. The plating apparatus 10E shown in this figure includes a processing tank 62 for storing a processing liquid, and a box-shaped plating jig 63 containing a cylinder block 4 of a 4-cycle engine as a work. The plating process is performed by being immersed.

The cylinder block 4 is placed inside the plating jig 63 with the combustion chamber side facing upward, and a seal jig 67 projecting from the bottom of the plating jig 63 is used for the crankcase of the cylinder 4 a. The opening on the side is sealed. Further, a lid 64 is mounted on the upper part of the plating jig 63 in a state where the lid is sealed with the cylinder block 4, and in this state, an opening 65 formed in the lid 64 is formed on the side of the combustion chamber side of the cylinder 4 a. It is designed to match the opening.

Then, an electrode 66 protrudes through the opening 65 of the lid 64, and the electrode 66 and the processing tank 6
2 is connected to an AC power supply 60 via an AC / DC converter 61.

According to the plating apparatus 10E, the plating jig 63 containing the cylinder block 4 is submerged in the processing solution in the processing tank 62, so that the cylinder block 4 is isolated by the plating jig 63. In the state
The processing liquid is stored in the cylinder 4a of the cylinder block 4 through the opening 65 of the lid 64. Then, in this state, a voltage is applied between the cylinder block 4 and the electrode 66 via the processing tank 62 and the plating jig 63, whereby a plating film is formed on the inner peripheral surface of the cylinder 4a.

Also in the plating apparatus 10E having such a configuration, the shape of the inner peripheral surface of the cylinder of the cylinder block 4 and the shape of the electrodes 66 are formed as in the first to sixth embodiments (in FIG. In addition, an example in which the inner peripheral surface is formed to expand upward is shown), and if necessary, a honing finish process is performed, whereby the plating process by the inner peripheral surface forming method of the present invention can be performed.

The method for forming the inner peripheral surface of the first to third embodiments is a typical embodiment of the present invention, and the specific contents thereof may be appropriately changed without departing from the scope of the present invention. Can be changed. For example, in the first to third embodiments, the plating film P formed on the inner peripheral surface of the cylinder is subjected to honing finishing, but such finishing is performed by chemical treatment other than honing. Finishing by processing may be used. However, regarding the finishing of the cylinder inner peripheral surface of the cylinder block, a large number of fine grooves are formed on the plating film surface by honing finishing, and during operation, lubricating oil accumulates in these fine grooves and the piston slides smoothly. In this respect, it is desirable to perform honing finishing.

Further, the specific configuration of the plating apparatus applied to the inner peripheral surface forming method of the first to third embodiments is not limited to that of the above embodiment, but can be changed as appropriate. For example, although not specifically described, the electrode may be either an insoluble electrode or a soluble electrode, and the flow direction of the processing liquid is opposite to that of each of the above-described embodiments, that is, the flow outside the electrode. The processing liquid may flow from the path to the flow path inside the electrode.

Further, the specific shape of the electrode may be appropriately selected so that the flow rate of the processing solution flowing between the workpiece and the electrode or the current density during the processing forms a desired plating film. Good.

[0096]

As described above, according to the method for forming an inner peripheral surface of the present invention, a plating film is formed on the inner peripheral surface of a cylindrical portion whose inner diameter changes in the axial direction. Is processed so as to be substantially parallel to the central axis of the cylindrical portion, so that the diameter of the inner peripheral surface of the plating film is uniformly formed in the axial direction, while the plating film has a large inner diameter at the cylindrical portion. On the contrary, the thickness of the plating film can be reduced at a portion where the inner diameter of the cylindrical portion is small. Therefore, it is possible to form a plating film suitable for the requirements of the surface to be processed, the shape, and the like, and therefore, it is possible to form a higher-quality plating film corresponding to the workpiece on the cylindrical portion.

In particular, if such a method is applied to the formation of the inner peripheral surface of the cylinder of the cylinder block of the engine, the inner peripheral surface of the cylinder serving as the piston sliding surface can be made more durable. In this case, if the inner diameter of the cylinder is formed so as to expand from the crankcase side of the cylinder toward the combustion chamber, wear or a plating film is likely to occur in the cylinder of the engine on the combustion chamber side. While the thickness of the plating film is increased, the inner diameter of the cylinder on which the plating film is formed can be made uniform in the axial direction to secure the piston sliding surface.

Further, if the inner diameter of the cylinder is formed so as to expand from the combustion chamber side of the cylinder toward the crankcase side, abrasion of the plating film occurs due to the tension of the piston ring in the engine cylinder. While increasing the thickness of the plating film on the crankcase side,
By making the inner diameter of the cylinder on which the plating film is formed uniform in the axial direction, it is possible to secure the piston sliding surface.

Further, if the inner diameter of the cylinder is formed so as to expand toward the combustion chamber side and the crankcase side from the axial center portion of the cylinder, wear or plating film peeling occurs in the engine cylinder. The inner diameter of the cylinder on which the plating film is formed is made uniform in the axial direction, while increasing the thickness of the plating film on the combustion chamber side, which is easy to wear, and on the crankcase side, where wear due to the tension of the piston ring is likely to occur. A piston sliding surface can be secured.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a plating apparatus applied to an inner peripheral surface forming method of the present invention.

FIG. 2 is an explanatory diagram illustrating a method of forming an inner peripheral surface according to a first embodiment.

FIG. 3 is an explanatory diagram illustrating a method of forming an inner peripheral surface according to a second embodiment.

FIG. 4 is an explanatory diagram illustrating a method of forming an inner peripheral surface according to a third embodiment.

FIG. 5 is a sectional view showing an inner circumferential surface of a cylinder obtained by the inner circumferential surface forming method of the first and fourth embodiments.

FIG. 6 is a sectional view showing an inner circumferential surface of a cylinder obtained by the inner circumferential surface forming method of the second and fifth embodiments.

FIG. 7 is a cross-sectional view showing an inner peripheral surface of a cylinder obtained by an inner peripheral surface forming method according to the third and sixth embodiments.

FIG. 8 is an explanatory diagram for explaining an inner peripheral surface forming method according to a fourth embodiment.

FIG. 9 is an explanatory view for explaining another example of the inner peripheral surface forming method of the fourth embodiment.

FIG. 10 is an explanatory diagram for explaining an inner peripheral surface forming method according to a fifth embodiment.

FIG. 11 is an explanatory diagram for explaining another example of the inner peripheral surface forming method of the fifth embodiment.

FIG. 12 is an explanatory diagram for explaining an inner peripheral surface forming method according to a sixth embodiment.

FIG. 13 is an explanatory diagram illustrating another example of the inner peripheral surface forming method of the sixth embodiment.

FIG. 14 is a schematic sectional view showing an apparatus for performing static bath plating.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 1a Cylinder 10A Plating apparatus 11 Support block 11a Opening 12 Processing liquid lead-out path 13 Electrode 14 Holder 15, 16 Flow path 17 Processing liquid introduction path 18 Sealing jig 19 Plate member 20 Columnar member 21 Seal member 31 Honing tool α1 Tilt angle P, Pa Plating film

Continuation of front page (56) References JP-A-8-277491 (JP, A) JP-A-63-20499 (JP, A) JP-B-37-12405 (JP, B1) Patent 157113 (JP, C2) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) C25D 7/04 C25D 5/48 F02F 1/00

Claims (9)

(57) [Claims] An inner diameter of a cylindrical portion of a work having a cylindrical portion is changed from one axial side of the cylindrical portion to the other, and an electrode is inserted into the cylindrical portion. After applying a voltage between the electrode and the workpiece in a state where the inner peripheral surface of the cylindrical portion and the electrode are filled with the processing liquid to perform plating on the inner peripheral surface of the cylindrical portion, the cylindrical portion A method for forming an inner peripheral surface of a cylindrical portion, wherein finishing is performed so that a surface of a plating film formed on an inner peripheral surface of the cylindrical portion is substantially parallel to a central axis of the cylindrical portion. 2. The cylindrical portion according to claim 1, wherein the plating process is performed such that the larger the inside diameter of the cylindrical portion is, the smaller the distance between the inner peripheral surface and the electrode is. Peripheral surface forming method. 3. The processing liquid is placed inside the cylindrical part by placing the work on the work supporting part and projecting an electrode serving also as a flow path constituent member protruding from the work supporting part into the cylindrical part of the work. 3. A tube according to claim 1, wherein a path for flowing the fluid is formed, and in this state, the processing liquid is supplied into the path to perform the plating treatment on the inner peripheral surface of the cylindrical portion. Method for forming the inner peripheral surface of the shaped part. 4. The method of forming an inner peripheral surface of a cylindrical part according to claim 1, wherein the inner peripheral surface of the cylinder is formed from the crankcase side of the cylinder to the combustion chamber side of the cylinder. 3. The method according to claim 1, wherein the plating process is performed by forming the tapered portion toward the front.
3. The method for forming an inner peripheral surface of a cylindrical portion according to any one of the above items 3 . 5. The method for forming an inner peripheral surface of a cylindrical portion according to claim 1, wherein the inner peripheral surface of the cylinder is formed from the combustion chamber side of the cylinder to the crankcase side. 3. The method according to claim 1, wherein the plating process is performed by forming the tapered portion toward the front.
3. The method for forming an inner peripheral surface of a cylindrical portion according to any one of the above items 3 . 6. A method for forming an inner peripheral surface of a cylindrical portion, the method comprising forming an inner peripheral surface of a cylinder of a cylinder block of an engine. The method for forming an inner peripheral surface of a cylindrical portion according to any one of claims 1 to 3 , wherein the plating process is performed by forming the flared portions toward the side and the crankcase side. 7. A engine cylinders formed in the cylinder peripheral surface by the inner circumferential surface forming process of the cylindrical portion of the fourth aspect, the thickness of the plating film in the cylinder peripheral surface from the crankcase side of the cylinder An inner plating engine cylinder characterized by being formed so as to gradually increase toward a combustion chamber side and to have a surface of a plating film parallel to a central axis of the cylinder. 8. An engine cylinder in which an inner peripheral surface of a cylinder is formed by the method for forming an inner peripheral surface of a cylindrical portion according to claim 5, wherein the thickness of the plating film on the inner peripheral surface of the cylinder is from the combustion chamber side of the cylinder. An internal plating engine cylinder characterized by being formed so as to gradually increase toward a crankcase side and to have a surface of a plating film parallel to a central axis of the cylinder. 9. An engine cylinder in which an inner peripheral surface of a cylinder is formed by the method for forming an inner peripheral surface of a cylindrical portion according to claim 6, wherein the thickness of the plating film on the inner peripheral surface of the cylinder is substantially the center of the cylinder in the axial direction. An inner plating engine cylinder characterized in that the inner plating engine cylinder is formed so as to gradually increase from a portion toward a combustion chamber side and a crankcase side, and that a surface of a plating film is parallel to a central axis of the cylinder.