JP6797482B2 - Manufacturing method of engine valve device, valve guide cylinder and valve guide cylinder - Google Patents

Description

The present invention relates to an engine valve device, and more particularly to a method of manufacturing an engine valve device, a valve guide cylinder, and a valve guide cylinder capable of suppressing sticking of a valve shaft in a valve guide cylinder.

Conventionally, there are the following valve devices for engines (see Patent Document 1).
An intake port, a poppet valve that opens and closes the valve opening of this intake port, a valve guide cylinder that guides the reciprocating movement of this poppet valve, a guide insertion hole into which this valve guide cylinder is inserted, and a port and a guide insertion hole. An engine valve device with a cylinder head.

This type of valve device has the advantage that the reciprocating movement of the poppet valve can be smoothly guided by the valve guide cylinder.

In this valve device, the inner circumference of the valve guide cylinder is provided with a sliding guide surface that guides the valve shaft of the poppet valve and a large tip diameter surface that has a larger inner diameter than the sliding guide surface, and has a large tip diameter surface. A tip gap opened toward the port is formed between the valve shaft and the valve shaft.

Jikkai Sho 59-28610 (see Fig. 2)

<< Problem >> The valve shaft may stick inside the valve guide cylinder.
In Patent Document 1, if the fuel is carbonized in the gap at the tip portion, the carbide may get caught between the valve shaft and the sliding guide surface, and the valve shaft may stick in the valve guide cylinder.

An object of the present invention is to provide an engine valve device, a valve guide cylinder, and a method for manufacturing a valve guide cylinder capable of suppressing sticking of a valve shaft in a valve guide cylinder.

(Matters specifying the invention of the invention according to claim 1)
As illustrated in FIG. 1 , reciprocation between at least one port (1) of intake and exhaust, a poppet valve (2) that opens and closes the valve port (1a) of this port (1), and the poppet valve (2). A valve guide cylinder (3) for guiding the movement, a guide insertion hole (4) into which the valve guide cylinder (3) is inserted, and a cylinder head (5) having a port (1) and a guide insertion hole (4). In the valve device of the engine provided, the following was done.

As illustrated in FIG. 1 , the inner circumference of the valve guide cylinder (3) includes a sliding guide surface (3a) that guides the valve shaft (2a) of the poppet valve (2) and the sliding guide surface (3a). It has a large diameter surface (3b) with a larger inner diameter than
The large diameter surface (3b) is between the large diameter surface (6a) of the tip portion provided in the tip portion (6) of the valve guide cylinder (3) on the port (1) side and the valve guide cylinder (3). A large surface (7a) having an intermediate diameter provided in the portion (7) is provided.
The sliding guide surface (3a) is formed from the tip-oriented guide surface (6b) provided between the tip diameter large surface (6a) and the intermediate diameter large surface (7a) and the intermediate portion diameter large surface (7a). Also has a base end side guide surface (8a) provided on the base end (8) side.

A gap (6c) in the tip portion opened toward the port (1) is formed between the large diameter surface (6a) of the tip portion and the valve shaft (2a), and the large diameter surface (7a) of the intermediate portion and the valve shaft (2a) are formed. An inner gap (7b) in the middle portion is formed between the two), and the inner gap (6c) in the tip portion and the inner gap (7b) in the middle portion have a tip-side annular ridge (6d) having a tip-side guide surface (6b) on the inner circumference. ) .
The exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) exposed in the port (1) when the poppet valve (2) is fully opened has a single diameter .
The gap (7b) in the intermediate portion is single, and the exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) is the tip portion (2ba) on the valve head (2c) side and the opposite end thereof. Of the base end portion (2bb) on the side, the base end portion (2bb) side is provided with the base end side exposed valve shaft end portion (2e), and the gap (7b) in the intermediate portion is the tip end portion of the valve guide cylinder (3). A gap end edge (7ba) on the tip end side on the (6) side is provided, and the exposed valve shaft end portion (2e) on the base end side exceeds the gap edge (7ba) on the tip end side when the poppet valve (2) is fully closed. The total length of the inner gap (7b) in the middle portion in the axial length is the inner gap of the tip (7b) with the direction along the axial length direction of the valve shaft (2a) as the axial length direction. An engine valve device characterized in that it is formed longer than the total length in the axial length direction of 6c).

(Matters specifying the invention of the invention according to claim 3 )
The valve guide cylinder used in the valve device of the engine according to claim 1 , as follows.

As illustrated in FIG. 1 , the inner circumference of the valve guide cylinder (3) includes a sliding guide surface (3a) that guides the valve shaft (2a) of the poppet valve (2) and the sliding guide surface (3a). It has a large diameter surface (3b) with a larger inner diameter than
The large-diameter surface (3b) is a large-diameter surface (6a) provided in the tip (6) of the valve guide cylinder (3) facing the port (1) side, and the valve guide cylinder (3). It is provided with a large diameter surface (7a) of the intermediate portion provided in the intermediate portion (7).
The sliding guide surface (3a) is formed from the tip-oriented guide surface (6b) provided between the tip diameter large surface (6a) and the intermediate diameter large surface (7a) and the intermediate portion diameter large surface (7a). Also has a base end side guide surface (8a) provided on the base end (8) side.

Tip large diameter surface (6a) and valve shaft (2a) tip the gap which is open toward the port (1) during the (6c) is configured to so that is formed, the intermediate portion a large diameter surface (7a) and it is configured so that the intermediate portion in the gap (7b) is formed between the valve shaft (2a), the distal end portion in the gap and (6c) an intermediate portion in the gap (7b) is the inner circumference near the tip end guide surface (6b) It is configured to be partitioned by a ring-shaped ridge (6d) near the tip .
The gap (7b) in the middle portion is single, and the gap (7b) in the middle portion is provided with the gap end edge (7ba) on the tip end side (6) side of the valve guide cylinder (3), and the poppet valve (2). Of the fully open exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) exposed in the port (1) when fully opened, the end side opposite to the tip portion (2ba) on the valve head (2c) side. The base end side exposed valve shaft end (2e) on the base end (2bb) side of the poppet valve (2) exceeds the tip side gap end edge (7ba) when the poppet valve (2) is fully closed, and the intermediate gap (7b) ) Is configured, and the direction along the axial length direction of the valve shaft (2a) is the axial length direction, and the total length of the intermediate portion inner gap (7b) in the axial length direction is the inner tip gap. (6c) A valve guide cylinder used in an engine valve device, which is configured to be formed longer than the total length in the axial length direction.

(Matters specifying the invention of the invention according to claim 4 )
The method for manufacturing a valve guide cylinder used in the valve device of an engine according to claim 3 .
As illustrated in FIG. 3 or 4, in manufacturing the valve guide cylinder (3) by sintering the metal powder (9).
A resin core (10) forming the inner circumference of the valve guide cylinder (3) is used during molding of the metal powder (9), and the heat generated during sintering of the metal powder (9) is used to generate the resin core (10). A method for manufacturing a valve guide cylinder, which comprises melting or thermally decomposing the resin core (10) from the sintered product of the valve guide cylinder (3).

(Invention according to claim 1 or claim 3 )
The invention according to claim 1 or claim 3 has the following effects.
<< Effect 1 >> It is possible to suppress the sticking of the valve shaft in the valve guide cylinder.
As illustrated in FIG. 1 or 2, in the present invention, even if the components of the unburned fuel in the exhaust and the EGR gas in the intake are carbonized in the gap (6c) in the tip and the guide surface (6b) near the tip. , The carbide is discharged and accumulated in the gap (7b) in the intermediate portion, and the problem that the carbide gets caught between the valve shaft (2a) and the sliding guide surface (3a) is suppressed, and the carbide is suppressed in the valve guide cylinder (3). It is possible to suppress the sticking of the valve shaft (2a).

<< Effect 2 >> The valve shaft has a high anti-sticking function in the valve guide cylinder.
As illustrated in FIG. 1 or 2, in the present invention, since the gap (6c) in the tip portion is opened toward the port (1), relatively high temperature exhaust and intake air in the gap (6c) in the tip portion are provided. Is replaced by the relatively low temperature exhaust and intake air passing through the port (1) by convection, and the heat accumulated in the tip (6) of the valve guide cylinder (3) is dissipated to the replaced exhaust and intake air, and the valve guide Overheating of the tip portion (6) of the cylinder (3) is suppressed. As a result, the formation of carbides in the gap (6c) in the tip portion and the guide surface (6b) near the tip portion is suppressed, and the function of suppressing the sticking of the poppet valve (2) in the valve guide cylinder (3) is high.

<< Effect 3 >> Uneven wear of the valve guide cylinder and valve shaft is suppressed.
As illustrated in FIG. 1 or 2, in the present invention, the valve shaft (2a) is supported by a relatively long support span extending the tip-side guide surface (6b) and the proximal end-side guide surface (8a), and is tilted. Since it is difficult, uneven wear of the valve guide cylinder (3) and the valve shaft (2a) is suppressed.
<< Effect 4 >> Damage to the poppet valve is suppressed.
The exposed valve shaft portion (2b) of the poppet valve (2), which receives a collision of exhaust gas and intake air passing through the port (1) at high speed when the poppet valve (2) is fully opened, has a single diameter. A corner portion that causes stress concentration and heat points is not formed in the portion (2b), and damage to the poppet valve (2) is suppressed.

(Invention according to claim 4 )
The invention according to claim 4 has the following effects.
<< Effect >> Manufacture of valve guide cylinders becomes easy.
Due to the heat generated when the metal powder (9) is sintered, the resin core (10) is melted and removed from the sintered product of the valve guide cylinder (3), or is burnt and removed by thermal decomposition. Therefore, the resin core (10) having an uneven outer circumference is easily removed from the sintered product of the valve shaft guide cylinder (3), and the valve guide cylinder (3) can be easily manufactured.

It is a vertical sectional view of the valve device of the engine which concerns on embodiment of this invention. Is. It is a vertical sectional view of the valve device of the engine which concerns on the reference embodiment of this invention. It is explanatory drawing of the manufacturing method of the valve guide cylinder used in the valve device of FIG. It is explanatory drawing of the manufacturing method of the valve guide cylinder used in the valve device of FIG.

1 is an engine valve device according to an embodiment of the present invention, FIG. 2 is an engine valve device according to a reference embodiment , FIG. 3 is a method for manufacturing a valve guide cylinder used in the valve device of FIG. 1, and FIG. 4 is FIG. In the figure explaining the manufacturing method of the valve guide cylinder used in the valve device, the exhaust valve device of a vertical diesel engine will be described in this embodiment and the reference embodiment .

First, an embodiment will be described.
As shown in FIG. 1, the exhaust valve device of this vertical diesel engine includes an exhaust port (1), a poppet valve (2) that opens and closes a valve port (1a) of the port (1), and the poppet valve. A cylinder having a valve guide cylinder (3) for guiding the reciprocating movement of (2), a guide insertion hole (4) into which the valve guide cylinder (3) is inserted, a port (1), and a guide insertion hole (4). It has a head (5).
This type of valve device has an advantage that the reciprocating movement of the poppet valve (2) can be smoothly guided by the valve guide cylinder (3).

The poppet valve (2) includes a valve shaft (2a) and a valve head (2c).
A ring-shaped valve seat (1b) is internally fitted at the opening end of the port (1), and a valve port (1a) is opened in the valve seat (1b).
This exhaust valve device includes a spring retainer (11) attached to the valve shaft (2a) of the poppet valve (2), and a valve spring (12) arranged between the spring retainer (11) and the cylinder head (5). A rocker arm (13) that is in contact with the valve shaft (2a) and a valve shaft seal (14) that is externally fitted to the base end of the valve guide cylinder (3) are provided, and the urging force of the valve spring (12). Then, the valve surface (2) of the valve head (2c) is seated on the valve seat (1b), and the pressing force of the rocker arm (13) resists the urging force of the valve spring (12), and the poppet valve (2) Lowers and the poppet valve (2) opens.

The configuration of the valve guide cylinder of this exhaust valve device is as follows.
As shown in FIG. 1, the inner circumference of the valve guide cylinder (3) is formed from a sliding guide surface (3a) that guides the valve shaft (2a) of the poppet valve (2) and the sliding guide surface (3a). Also has a large diameter surface (3b) with a large inner diameter.
The large diameter surface (3b) is between the large diameter surface (6a) of the tip portion provided in the tip portion (6) of the valve guide cylinder (3) on the port (1) side and the valve guide cylinder (3). It is provided with a large intermediate diameter surface (7a) provided in the portion (7).
The sliding guide surface (3a) is formed from the tip-oriented guide surface (6b) provided between the tip diameter large surface (6a) and the intermediate diameter large surface (7a) and the intermediate portion diameter large surface (7a). Also has a base end side guide surface (8a) provided on the base end (8) side.

A gap (6c) in the tip portion opened toward the port (1) is formed between the large diameter surface (6a) of the tip portion and the valve shaft (2a), and the large diameter surface (7a) of the intermediate portion and the valve shaft (2a) are formed. An inner gap (7b) in the middle portion is formed between the two), and the inner gap (6c) in the tip portion and the inner gap (7b) in the middle portion have a tip-side annular ridge (6d) having a tip-side guide surface (6b) on the inner circumference. ).

As shown in FIG. 1, the tip end portion (6) of the valve guide cylinder (3) is housed in the guide insertion hole (4), and the inner peripheral surface of the guide insertion hole (4) and the valve guide cylinder (3). A tip outer gap (4a) opened toward the port (1) is formed between the tip (6).

In this embodiment, since the tip outer gap (4a) is opened toward the port (1), exhaust gas and intake air that have become relatively hot in the tip outer gap (4a) are inside the port (1). The heat accumulated in the tip (6) of the valve guide cylinder (3) is dissipated to the replaced exhaust and intake air by convection with the relatively low temperature exhaust and intake air passing through the valve guide cylinder (3). Overheating of part (6) is suppressed. As a result, the formation of carbides in the gap (6c) in the tip portion and the guide surface (6b) near the tip portion is suppressed, and the function of suppressing the sticking of the poppet valve (2) in the valve guide cylinder (3) is high.

As illustrated in FIG. 1 , in this embodiment, the exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) exposed in the port (1) when the poppet valve (2 ) is fully opened. However, it is said to have a single diameter.
In this embodiment, the exposed valve shaft portion (2b) of the poppet valve (2), which receives a collision of exhaust gas or intake air passing through the port (1) at high speed when the poppet valve (2) is fully opened, has a single diameter. Therefore, the exposed valve shaft portion (2b) is not formed with a corner portion that causes stress concentration and heat points, and damage to the poppet valve (2) is suppressed.
The gap (7b) in the middle portion is single, and the exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) is the tip portion (2ba) on the valve head (2c) side and the opposite end thereof. Of the base end portion (2bb) on the side, the base end portion (2bb) side is provided with the base end side exposed valve shaft end portion (2e), and the gap (7b) in the intermediate portion is the tip portion (3) of the valve guide (3). A gap end edge (7ba) on the tip end side on the 6) side is provided, and when the poppet valve (2) is fully closed, the exposed valve shaft end portion (2e) on the base end side exceeds the gap end edge (7ba) on the tip end side. It is configured to reach the recessed portion (7b) in the middle portion, and the total length of the gap (7b) in the intermediate portion in the axial length direction is the gap (6c) in the tip portion, with the direction along the axial length direction of the valve shaft (2a) as the axial length direction. ) Is formed longer than the total length in the axial length direction.
That is, the valve guide cylinder (3) is configured as follows.
The gap (7b) in the middle portion is single, and the gap (7b) in the middle portion is provided with the gap end edge (7ba) on the tip end side (6) side of the valve guide cylinder (3), and the poppet valve (2). Of the fully open exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) exposed in the port (1) when fully opened, the end side opposite to the tip portion (2ba) on the valve head (2c) side. The exposed valve shaft end (2e) on the base end side on the base end (2bb) side of the poppet valve (2) exceeds the gap end edge (7ba) on the tip side when the poppet valve (2) is fully closed, and the gap (7b) in the middle portion is exceeded. ) Is configured, and the direction along the axial length direction of the valve shaft (2a) is the axial length direction, and the total length of the intermediate portion inner gap (7b) in the axial length direction is the inner tip gap. It is configured to be formed longer than the total length in the axial length direction of (6c).

Next, a reference embodiment of the present invention will be described.
As shown in FIG. 2, in this reference embodiment , the intermediate portion inner gap (7b) is a plurality of divided gaps partitioned by an intermediate portion annular ridge (7d) having an intermediate portion guide surface (7c) on the inner circumference. It is composed of (7e) and (7e), and the plurality of division gaps (7e) and (7e) are arranged side by side in the vertical direction which is the axial length direction of the valve guide cylinder (3).
Other configurations are the same as those of the embodiment shown in FIG.
In FIG. 2, the same elements as those in the embodiment are designated by the same reference numerals as those in FIG.

In this reference embodiment , the carbides that have emerged from the gap inside the tip portion (6c) via the guide surface (6b) near the tip portion sequentially rise to the upper split gaps (7e) and (7e) via the upper intermediate guide surface (7c). However, since the carbides are dispersed and accumulated in the plurality of divided gaps (7e) and (7e) little by little, the load of the carbides accumulated in the intermediate inner gaps (7b) prevents the carbides from floating from the guide surface (6c) near the tip. The heat transfer from the defective part to the base end (8) side of the valve guide cylinder (3) is blocked by the intermediate annular ridge (7d), and the base end portion (8) of the valve guide cylinder (3) is blocked. The temperature rise is suppressed. As a result, thermal damage to the valve shaft seal (11) provided at the base end (8) of the valve guide cylinder (3) is suppressed.

Further, in this reference form , since the intermediate portion inner gap (7b) is divided into a plurality of divided gaps (7e) and (7e) by the intermediate portion annular ridge (7d), it is intermediate from the tip inner portion inner gap (6c). The heat transfer to the base end (8) side of the valve guide cylinder (3) through the internal gap (7b) is blocked by the intermediate annular ridge (7d), and the base end portion of the valve guide cylinder (3). The temperature rise in (8) is suppressed. As a result, thermal damage to the valve shaft seal (11) provided at the base end (8) of the valve guide cylinder (3) is suppressed.

In the above embodiment and the reference embodiment , the exhaust port (1) and the poppet valve (2) used therefor have been described, but in the embodiment and the reference embodiment , the intake port and the poppet valve used therefor have the same structure. ing.

Next, a method of manufacturing the valve guide cylinder used in the embodiment shown in FIG. 1 will be described.
As shown in FIG. 3, in this manufacturing method, when the valve guide cylinder (3) is manufactured by sintering the metal powder (9), the inner circumference of the valve guide cylinder (3) is formed when the metal powder (9) is molded. The resin core (10) to be formed is used.
Next, the resin core (10) is melted or thermally decomposed by the heat generated during the sintering of the metal powder (9), and the resin core (10) is separated from the sintered product of the valve guide cylinder (3). except.

In this embodiment, the heat generated during the sintering of the metal powder (9) causes the resin core (10) to flow out of the sintered product of the valve guide cylinder (3) due to melting, or is removed by thermal decomposition. Since it is burnt out and removed, the resin core (10) having an uneven outer circumference is easily removed from the sintered product of the valve shaft guide cylinder (3), and the valve guide cylinder (3) can be easily manufactured.

An iron-based sintered metal material is used for the metal powder (9).
The metal powder (9) is press-molded by the mold (15). The mold (15) has a die (15c) provided with a cavity (15a) for filling the metal powder (9), a supply port (15b) for supplying the metal powder (9) to the cavity (15a), and a die (15c). It is composed of upper and lower punches (15d) and (15e) that move up and down inside the.
As the resin core (10), a thermoplastic resin such as nylon or a thermosetting resin such as a phenol resin can be used.
When a thermoplastic resin is used for the resin core (10), the resin core (10) is removed from the sintered product of the valve guide cylinder (3) by melting.
When a thermosetting resin is used for the resin core (10), the resin core (10) is removed from the sintered product of the valve guide cylinder (3) by thermal decomposition.
As the resin core (10), one reinforced with fibers such as glass fiber is used.
On the outer circumference of the resin core (10), in order from the tip side, the tip diameter large surface (6a), the tip-side guide surface (6b), the intermediate diameter large surface (7a), and the proximal end side guide surface ( Concavities and convexities for forming 8a) are formed.

FIG. 4 shows a manufacturing method of the valve guide cylinder used in the reference form shown in FIG.
As shown in FIG. 4, this manufacturing method is also the same as the manufacturing method shown in FIG.
In FIG. 4, the same elements as those in FIG. 3 are designated by the same reference numerals as those in FIG.
On the outer circumference of the resin core (10), in order from the tip side, the tip diameter large surface (6a), the tip-side guide surface (6b), the middle diameter large surface (7a), and the intermediate guide surface (7c) ), Concavities and convexities for forming the base end side guide surface (8a) are formed.

(1) ... Port, (1a) ... Valve port, (2) ... Poppet valve, (2a) ... Valve shaft, (2b) ... Exposed valve shaft part when fully open , (2ba) ... Tip part, (2bb) ... Base End, (2e) ... Base end side exposed valve shaft end, (3) ... Valve guide cylinder, (3a) ... Sliding guide surface, (3b) ... Large diameter surface, (4) ... Guide insertion hole, (4a) ... Tip outer gap, (5) ... Cylinder head, (6) ... Tip, (6a) ... Tip diameter large surface, (6b) ... Tip guide surface, (6c) ... Tip inner gap, (6d) ... Circular ridge near the tip, (7) ... Middle part, (7a) ... Middle diameter large surface, (7b) ... Middle part inner gap , (7ba) ... Tip side gap edge, (7d) ... Intermediate annular ridge , (8) ... Base end, (8a) ... Base end side guide surface, (9) ... Metal powder, (10) ... Resin core.

Claims (4)

At least one port (1) of exhaust and intake, a poppet valve (2) that opens and closes the valve port (1a) of this port (1), and a valve guide cylinder (2) that guides the reciprocating movement of the poppet valve (2). In an engine valve device provided with 3), a guide insertion hole (4) into which the valve guide cylinder (3) is inserted, and a cylinder head (5) having a port (1) and a guide insertion hole (4). ,
The inner circumference of the valve guide cylinder (3) is a sliding guide surface (3a) that guides the valve shaft (2a) of the poppet valve (2) and a large diameter surface having an inner diameter larger than that of the sliding guide surface (3a). With (3b)
The large diameter surface (3b) is between the large diameter surface (6a) of the tip portion provided in the tip portion (6) of the valve guide cylinder (3) on the port (1) side and the valve guide cylinder (3). A large surface (7a) having an intermediate diameter provided in the portion (7) is provided.
The sliding guide surface (3a) is formed from the tip-oriented guide surface (6b) provided between the tip diameter large surface (6a) and the intermediate diameter large surface (7a) and the intermediate portion diameter large surface (7a). Also provided with a base end side guide surface (8a) provided on the base end (8) side.
A gap (6c) in the tip portion opened toward the port (1) is formed between the large diameter surface (6a) of the tip portion and the valve shaft (2a), and the large diameter surface (7a) of the intermediate portion and the valve shaft (2a) are formed. An inner gap (7b) in the middle portion is formed between the two), and the inner gap (6c) in the tip portion and the inner gap (7b) in the middle portion have a tip-side annular ridge (6d) having a tip-side guide surface (6b) on the inner circumference. ) ,
The exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) exposed in the port (1) when the poppet valve (2) is fully opened has a single diameter .
The gap (7b) in the intermediate portion is single, and the exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) is the tip portion (2ba) on the valve head (2c) side and the opposite end thereof. Of the base end portion (2bb) on the side, the base end portion (2bb) side is provided with the base end side exposed valve shaft end portion (2e), and the gap (7b) in the intermediate portion is the tip end portion of the valve guide cylinder (3). A gap end edge (7ba) on the tip end side on the (6) side is provided, and the exposed valve shaft end portion (2e) on the base end side exceeds the gap edge (7ba) on the tip end side when the poppet valve (2) is fully closed. The total length of the inner gap (7b) in the middle portion in the axial length is the inner gap of the tip (7b) with the direction along the axial length direction of the valve shaft (2a) as the axial length direction. An engine valve device characterized in that it is formed longer than the total length in the axial length direction of 6c). In the valve gear of the engine according to claim 1 .
The tip (6) of the valve guide cylinder (3) is housed in the guide insertion hole (4), and is between the inner peripheral surface of the guide insertion hole (4) and the tip (6) of the valve guide cylinder (3). An engine valve device characterized in that a tip outer gap (4a) is formed in the port (1). A valve guide cylinder used in the valve device of the engine according to claim 1 .
The inner circumference of the valve guide cylinder (3) is a sliding guide surface (3a) that guides the valve shaft (2a) of the poppet valve (2) and a large diameter surface having an inner diameter larger than that of the sliding guide surface (3a). With (3b)
The large-diameter surface (3b) is a large-diameter surface (6a) provided in the tip (6) of the valve guide cylinder (3) facing the port (1) side, and the valve guide cylinder (3). It is provided with a large diameter surface (7a) of the intermediate portion provided in the intermediate portion (7).
The sliding guide surface (3a) is formed from the tip-oriented guide surface (6b) provided between the tip diameter large surface (6a) and the intermediate diameter large surface (7a) and the intermediate portion diameter large surface (7a). Also provided with a base end side guide surface (8a) provided on the base end (8) side.
Tip large diameter surface (6a) and valve shaft (2a) tip the gap which is open toward the port (1) during the (6c) is configured to so that is formed, the intermediate portion a large diameter surface (7a) and it is configured so that the intermediate portion in the gap (7b) is formed between the valve shaft (2a), the distal end portion in the gap and (6c) an intermediate portion in the gap (7b) is the inner circumference near the tip end guide surface (6b) It is configured to be partitioned by a ring-shaped ridge (6d) near the tip .
The gap (7b) in the middle portion is single, and the gap (7b) in the middle portion is provided with the gap end edge (7ba) on the tip end side (6) side of the valve guide cylinder (3), and the poppet valve (2). Of the fully open exposed valve shaft portion (2b) of the valve shaft (2a) of the poppet valve (2) exposed in the port (1) when fully opened, the end side opposite to the tip portion (2ba) on the valve head (2c) side. The base end side exposed valve shaft end (2e) on the base end (2bb) side of the poppet valve (2) exceeds the tip side gap end edge (7ba) when the poppet valve (2) is fully closed, and the intermediate gap (7b) ) Is configured, and the direction along the axial length direction of the valve shaft (2a) is the axial length direction, and the total length of the intermediate portion inner gap (7b) in the axial length direction is the inner tip gap. (6c) A valve guide cylinder used in an engine valve device, which is configured to be formed longer than the total length in the axial length direction. The method for manufacturing a valve guide cylinder used in the valve device of an engine according to claim 3 .
In manufacturing the valve guide cylinder (3) by sintering the metal powder (9),
A resin core (10) forming the inner circumference of the valve guide cylinder (3) is used during molding of the metal powder (9), and the heat generated during sintering of the metal powder (9) is used to generate the resin core (10). A method for manufacturing a valve guide cylinder, which comprises melting or thermally decomposing the resin core (10) from the sintered product of the valve guide cylinder (3).

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