JPS63227952A - Solenoid-operated fuel injection valve casting and its manufacture - Google Patents

Abstract

PURPOSE:To easily manufacture a valve casing, by concurrently providing a valve guide surface and a fuel flow path groove in the internal peripheral surface of a fit mounting part, in case of the valve casing which has the fit mounting part slidably mounting a valve unit to be fitted and a valve seat part receiving said valve unit. CONSTITUTION:A valve casing 9 is mounted to the bottom center of a yoke 3 which internally mounts an electromagnetic coil, and the valve casing 9 has an opening part 10 introducing one part of a rod 6 associated with a plunger 5 and ensuring a flow path around the rod 6, fit mounting part 11 forming a diameter smaller than that of said opening part 10 slidably mounting a ball 7 to be fitted, valve seat part 12 of tapered shape successively provided in the bottom end of said fit mounting part 11 and a nozzle mounting hole 13 mounting an injection nozzle 14. The ball fit mounting part 11 forms in its internal peripheral surface a valve guide surface 11a forming almost the same diameter to the ball 7 coming into contact with the peripheral surface of the ball and a fuel flow path groove 11b constituted forming one part of said guide surface 11a to be recessed in the outside direction and concurrently provided in the peripheral direction with the guide surface 11a.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electromagnetic fuel injection valve used to supply fuel to an internal combustion engine, and more particularly to a valve casing of a fuel injection valve and a method for manufacturing the same. It is.

[Conventional technology]

Generally, electromagnetic fuel injection valves that supply fuel to internal combustion engines are disclosed in, for example, Japanese Unexamined Patent Application Publication No. 58-13135 and Japanese Utility Model Application No. 59-56.
As disclosed in Publication No. 371, etc., a valve casing (valve guide) having a nozzle and a valve seat is attached to one end of the fuel injection valve main body, and a ball-shaped, needle-shaped, etc. valve body is installed inside this valve casing. It is fitted. Then, the valve element is electromagnetically attracted through the plunger by energization of the electromagnetic coil, thereby performing a valve opening operation, and in this way, fuel injection is performed. This type of valve casing is usually designed so that the inner circumferential surface of the valve casing functions as a guide when the valve element slides. The diameter of the part of the rod (needle) to be supported is approximately the same as that of the rod (the largest diameter part of the rod), and the valve body or part of the rod is in contact with the inner periphery of the valve casing (including a state of near contact). The casing allows for smooth sliding guidance.

By the way, when the valve body or part of the rod is made to have approximately the same diameter as the inner diameter of the valve casing, the inner circumference of the valve casing and the outer circumferential surface of the valve body or rod come into contact with each other. Since it is not possible to secure a fuel flow path in the N state, conventionally the outer circumferential surface of the valve body or lot is partially cut out by grinding and polishing, and in this way, the outer circumference of the valve body, etc. A flow path space was secured between the surface and the inner peripheral surface of the valve casing.

[Problem that the invention seeks to solve]

As mentioned above, conventional fuel injection valves secure a fuel flow path space by providing a cutout surface in a part of the valve body or rod on the side that is slidably guided by the valve casing. , n'5Z requires relatively expensive grinding, etc., and even when providing a notch surface on the valve body, the inner diameter of the remaining portion of the valve casing is Since it is necessary to secure a certain amount of surface with approximately the same diameter as the valve body, there are restrictions on securing the flow path area.In order to secure a sufficient flow path area, the diameter of the valve body and lot must be If the inner diameter of the valve casing and other dimensions were not increased, the entire device would become larger. Also,
Regarding valve casings, conventionally, the internal space in which the valve body is fitted, the valve seat part, etc. are formed by electric discharge machining, etc., and then the valve seat part, etc. is polished. When the series of machining operations are combined with the aforementioned grinding operations for the valve body, etc., there are many overall operation steps, and it has been desired to improve these problems from the viewpoint of manufacturing costs.

The present invention has been made in view of the above points, and an object thereof is to sufficiently secure the valve guide surface and flow path space between the inner circumferential surface of this type of valve casing and the outer circumferential surface of the valve body. It is an object of the present invention to provide a valve casing for a fuel injection valve and a method for manufacturing the same, which can achieve a significant reduction in manufacturing cost by streamlining the manufacturing process of the valve casing while ensuring the same.

[Means for solving problems]

In order to achieve the above object, the present invention constitutes a valve casing of this type as follows as a first invention.

That is, in an electromagnetic fuel injection valve which constitutes a part of the electromagnetic fuel injection valve and has a fitting part into which a valve element is slidably fitted, and a valve seat part which receives the valve element, the above-mentioned The inner circumferential surface of the fitting part is provided with a valve guide surface having the same diameter as the valve body and for slidingly guiding the valve body, and a part of the valve guide surface being recessed so that the valve body can be guided by the valve guide surface. A fuel flow groove that secures a fuel flow space between the outer peripheral surface of the body and the fuel flow groove is installed in parallel.
Constitutes the valve casing.

Moreover, as a second invention, the following method of manufacturing a valve casing is provided.

That is, first, a hole to be machined for hobbing is formed on the inner periphery of a cylindrical body that is a material for the valve casing, the inner diameter of which is smaller than the diameter of this cylindrical body. By applying hobbing pressure to one end of the hole to be machined through the opening at one end of the cylindrical body, a valve body having approximately the same diameter as the valve body of the electromagnetic fuel injection valve is formed in the hole to be machined. A valve guide surface for fitting and slidingly guiding the valve, a concave fuel flow groove arranged circumferentially in parallel with the valve guide surface, and a valve seat portion for receiving the valve body are hobbed. mold at the same time.

[Effect]

According to the present invention having such a configuration, in the first invention, on the valve body fitting part side of the valve casing side,
Since a concave fuel flow groove is arranged in parallel with the valve guide surface of approximately the same diameter as the valve body, a space for the fuel flow is secured between the fuel flow groove on the valve casing side and the outer peripheral surface of the valve body. can do.

In the case of the present invention, sufficient fuel flow space can be secured between the valve body and the inner peripheral surface of the valve casing by simply setting the degree of recess of the fuel flow groove. ,
In addition, since the area of the flow path groove depends on the depth of the groove, a sufficient valve guide surface can be secured without sacrificing the area. Further, according to the present invention, since the fuel flow groove is provided on the valve casing side, there is no need to perform grinding on the valve body side to provide a cutout surface for securing the flow path as in the conventional case. Furthermore, when the valve guide surface and the fuel flow groove are arranged side by side on the valve casing side, the valve guide surface and the fuel flow groove can be formed by simply applying processing means such as plastic deformation to a part of the inner circumference of the valve casing. It becomes possible to mold the material into a mold.

That is, as in the valve casing manufacturing method in the second invention, processing pressure is simply applied by a hob of a predetermined shape to the hole to be machined inside the cylindrical body through the opening at one end of the cylindrical body that is the material of the valve casing. A valve guide surface as in the first invention described above.

The fuel flow channel groove and the valve seat portion can be plastic-processed simultaneously in one process.

According to this manufacturing method, there is no need to form a notch for a flow path on the valve body side or to form a valve body fitting part and a valve seat part in separate operations on the valve casing side as in the past.
The number of work processes in manufacturing valve casings has been significantly reduced and streamlined.

Moreover, since the valve casing is hobbed, it can be mass-produced without variations in accuracy, improving accuracy.

can be achieved.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 to 7.

FIG. 1 is a longitudinal cross-sectional view of the electromagnetic fuel injection valve in this embodiment. In the figure, 1 is the main body of the fuel injection valve, 2 is the electromagnetic coil, and
4 is the core that constitutes the magnetic circuit of the electromagnetic coil 2 together with the yoke 3; 5 is the yoke 3;
A rod 6 is provided integrally with the plunger 5, and a ball (valve body) 7 is attached to the lowermost end of the rod 6. Plunger 5
constitutes a magnetic circuit together with the yoke 3 and the core 4, and when the electromagnetic coil 2 is energized, the plunger 5 is attracted and moved against the spring 8 with a predetermined stroke, and this attraction moves the rod 6.
Then, the ball 7 is pulled up, and the ball 7 separates from the valve seat portion 12, which will be described later, to open the valve. At this time, fuel is injected through the nozzle 12.

9 is a valve casing that is attached to the center of the lower end of the yoke 3 and constitutes a part of the injection valve body 1;
has a rectangular cylindrical shape, and has an opening 10 in which a part of the rod 6 is introduced to secure a flow path around the rod 6.
and from the opening 10.

A fitting part 11 having a small diameter and slidably fitting the ball 7, a valve seat part 12 tapered from the lower end of the fitting part 11 to receive the ball 7, and a valve seat part 12 provided downstream from the valve seat part 12. The nozzle mounting hole 1 has a nozzle mounting hole 13.
A fuel injection nozzle 14 is attached to 3.

Figure 2 is a cross-sectional view taken along line A-A in Figure 1, and Figure 3 is B in Figure 1.
4 shows a sectional view taken along the line CC in FIG. 3, and the internal structure of the valve casing 9 will be described in detail based on these drawings.

The inner peripheral surface of the ball fitting part 11 of the valve casing 9 has
A valve guide surface 11a has approximately the same diameter as the ball 7 and is in contact with the outer circumferential surface of the ball 7, and a portion of the valve guide surface 11a is recessed outwardly so that the valve guide surface 11a is arranged in parallel with the valve guide surface 11a in the circumferential direction. A fuel flow groove 11b is arranged. The valve guide surface 11a is in contact with a part of the outer peripheral surface of the ball 7 and guides the sliding movement of the ball 7 during the pongee valve operation.
Further, the flow path groove 11b secures a space S (shown in FIG. 2) in which the fuel flows between the flow path groove 11b and the outer circumferential surface of the ball 7.

The fuel flow groove 11b in this example includes four flow grooves 11b.
are arranged at equal intervals in the circumferential direction, and each channel groove 11b
The shape of the outermost diameter portion of the groove 11b is curved to facilitate plastic working of the groove 11b, that is, to make the plastic flow smooth.

The valve seat portion 12 is connected to the ball fitting portion 11 as described above.
Although the seat portion 12 is tapered and narrow, the seat portion 12 is formed into a straight line or a convex curved shape as shown in FIG. 4 to ensure smooth fuel flow when the valve is opened and to prevent contact with the outer peripheral surface of the ball 7. This is to ensure a sufficient amount to ensure good sheeting properties. Further, a fuel hole 15 is formed at the lower side of the seat portion 12.

Therefore, in the valve casing having such an internal structure, when the electromagnetic coil 2 is energized, the rod 6 and the ball 7 are attracted through the plunger 5 within the regulated range of the stopper 16, and the ball 7 is attracted to the valve guide surface 11a. The valve is slidably guided by the ball 7 to open the valve, and at this time, fuel flows toward the nozzle 14 through the space S formed by the outer circumferential surface of the ball 7 and the flow path groove 11b, and fuel injection is performed.

Next, a method for manufacturing the above-mentioned valve casing will be explained based on FIGS. 5 to 7. FIG. 5 is a cutaway perspective view showing an intermediate process (before hobbing) of the valve casing 9. In this state, the ball fitting part (valve guide surface 11a , the flow path groove 11b) 11, the seat portion 12, and the portion other than the fuel hole 15 are finished into the final shape, and a hole to be machined with a diameter smaller than the diameter (inner diameter) of the opening 10 of the cylindrical body 9' is formed on the inner periphery. 11'
is formed. The cylindrical body 9' is made of, for example, a stainless steel material that has excellent corrosion resistance against gasoline fuel and has metallic plasticity. Therefore, the hole 1 to be machined in the cylindrical body 9'
1' is processed by a hobbing processing device as shown in FIG. That is, 2o in FIG. 7 is a carbide layer punch, and the punch 20 has the valve guide surface 11a described above,
A hob having concavities and convexities opposite to the channel groove 11b, the seat portion 12, and the fuel hole 15 is formed, and the punch 20 is inserted into the cylindrical body 9.
' through the opening 10 of the to-be-processed hole 11' to one end of the to-be-processed hole 11', and on the other hand, a female piece 21 that receives hobbing pressure is set at the other end of the to-be-processed hole 11', and the female die 22 is used to insert the cylindrical body 9'
If the outer periphery of the valve guide surface 11a, the flow path groove 11b, the seat part 12 and the fuel hole 15 are pressed by pressing the processed hole 11' of the cylindrical body 9' using a press machine such as hydraulic pressure in this state, are simultaneously hobbed in one process. FIG. 5 shows the valve casing 9 after hobbing.

According to this embodiment, structurally, the ball fitting portion 11 of the valve casing 9 has a valve guide surface 11a that has approximately the same diameter as the ball 7 and slides and guides the ball 7.
and the flow passage groove 11b are arranged side by side in the circumferential direction, so there is no need to provide a notch surface by grinding on a valve body such as a ball or the like as in the past to secure a fuel flow passage. Ball 7 can be used in its original shape. Also, ball 7
Since the area of the flow path space S secured between the ball fitting portion 11 and the flow path groove 11 is arbitrarily set depending on the depth of the flow path groove 11b, the flow path groove 11b sacrifices the valve guide surface 11a. It is possible to secure a sufficient fuel flow path without any problems. Therefore, even when applying a fuel injection valve to a large engine, etc., where the amount of fuel injected per unit time is relatively large, it can be accommodated by increasing the depth of the flow groove, making the overall device more compact. can be achieved.

In addition, the valve casing in this embodiment is formed by hobbing so as to form the valve guide surface 11a, the flow path groove 11b, and the seat portion 1 in the valve fitting portion 11 in one process.
2. Since the fuel hole 15 can also be formed at the same time, valve casings can be mass-produced without variations in one-plane accuracy or coaxiality.

Moreover, unlike conventional methods, it is no longer necessary to grind a cutout surface for a flow path on the valve body side or to secure a cylindrical space for fitting a valve body etc. on the valve casing side by electrical discharge machining, etc., making it possible to manufacture the valve casing. It is possible to reduce the number of work processes and achieve significant rationalization. Therefore, manufacturing costs can be significantly reduced.

〔Effect of the invention〕

As described above, according to the present invention, both the valve guide surface and the flow path space between the inner circumferential surface of this type of valve casing and the outer circumferential surface of the valve body can be sufficiently secured, and in addition, the manufacturing process of the valve casing This makes it possible to rationalize the process and, in turn, significantly reduce manufacturing costs. In this embodiment, a ball-shaped valve body is used as an example of a valve body to be fitted into a valve casing, but other valves such as needle-shaped valves may have a similar valve casing structure.

can be realized.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an example of an electromagnetic twist injection valve to which the present invention is applied, FIG. 2 is a sectional view taken along line 11i16-A,
Figure 3 is B-B in Figure 1. Figure 4 is C-C in Figure 3.
A line sectional view, FIGS. 5 and 6 are partially cutaway perspective views showing the manufacturing process of the valve seat 2 in the fuel injection valve, and FIGS.
Figure &: Table 4 is a sectional view showing the state of hobbing of the valve casing. 1... Electromagnetic fuel injection valve, 2... Electromagnetic coil, 6...
・Rad, 7... Valve body (ball), 9... Valve seat tag, 9'... Cylindrical body, 1o... Opening, 11...
・Valve fitting part, 11'... Hole to be machined, lla... Valve seat, llb... Fuel passage groove, 12... Valve seat 2o... Hobbing processing means, S... Flow road space.

Claims (2)

[Claims] 1. The valve constitutes a part of the electromagnetic fuel injection valve and comprises a fitting part into which a valve element is slidably fitted, and a valve seat part which receives the valve element, wherein the fitting part A valve guide surface is formed on the inner circumferential surface of the valve body, and has a valve guide surface that has approximately the same diameter as the valve body and slides the valve body, and a valve guide surface that is formed on the valve guide surface and is connected to the outer circumferential surface of the valve body. A valve casing for an electromagnetic fuel injection valve characterized by having fuel flow grooves arranged in parallel to ensure a flow space for fuel. 2. On the inner circumference of the cylindrical body that is the material of the valve casing,
By forming a hobbing hole with an inner diameter smaller than the diameter of the cylindrical body, and applying hobbing pressure to one end of the hole through an opening at one end of the cylindrical body, the hobbing process is performed. A valve guide surface having approximately the same diameter as the valve body of the electromagnetic fuel injection valve and for slidingly guiding the valve body while fitting the valve body in the hole, and a valve guide surface arranged in parallel with the valve guide surface in the circumferential direction. A method for manufacturing a valve casing for an electromagnetic fuel injection valve, characterized in that a concave fuel flow groove and a valve seat portion for receiving the valve body are simultaneously formed by hobbing.