JPS627911A - Relief valve of engine - Google Patents

Abstract

PURPOSE:To stabilize the oil pressure, and make it unnecessary to form a relief opening through machining, by forming a relief oil route which is on the lower course of a valve body, of a slit-shaped groove which extends along the moving direction of the valve body. CONSTITUTION:An oil route which is on the lower coarse of a valve body 20, in a relief valve 19, is formed of a slit-shaped groove 25 which extends along the moving direction 23 of the valve body 20. Then, the moving length L of the valve body 20 is proportional to the opening area S of the groove 25. Accordingly, the oil pressure in a discharge oil route 17 is stabilized, because the higher the pressure in the discharge oil route 17 becomes, the moving length L increases, the opening area S of the groove 25 increases, and consequently, the relief quantity increases. The groove 25 can be formed by casting at the same time as forming a spring chamber 22, that is, a moving route for the valve body 20, because this groove 25 extends along the moving direction 23 of the valve body 20, so it is not necessary that the relief opening is formed by machining, afterwards, and consequently, the relief valve 19 can be manufactured easily.

Description

Detailed Description of the Invention [Industrial Application Field] This invention relates to an oil used to lubricate around drive shafts in an engine such as an engine camshaft and crankshaft, and other sliding parts in an engine. Concerning a relief valve for adjusting hydraulic pressure leading to a pump.

[Prior Art] In order to lubricate the area around the drive shaft and sliding parts inside the engine, an oil pump that utilizes power extracted from the crankshaft is usually used. Incidentally, since such an oil pump extracts its power from the crankshaft of the engine, its rotational speed changes in accordance with changes in the output of the engine, and inevitably the discharge pressure of the oil pump also changes.

However, if the discharge pressure becomes too high, the load on the oil pump, that is, the engine load, becomes excessive, which is not preferable. Therefore, a relief valve for adjusting the oil pressure is installed in the middle of the oil passage leading to the oil pump discharge port, and when the oil discharge pressure exceeds a certain value, the valve automatically opens, allowing some of the oil to escape. The oil that escapes from the guide passage of the relief valve is collected in the oil tank. As an example of this type of relief valve,
The device described in Japanese Patent No. 37809 will be explained with reference to FIGS. 8 and 9.

In these figures, first, oil sucked up from an intake pipe B by an oil pump A is discharged from an oil pump discharge pipe C and sent to various parts within the engine. When the pressure in the passage becomes higher than a certain value by -L, the valve body F of the relief valve E moves downward as shown in the figure, and the relief hole G, which is formed by a single circular hole opening in the side wall of the boss, opens and the oil is released. Let the oil pass through the guide path H and collect it in the oil tank ■.

[Problems to be Solved by the Invention] In the relief valve as described above, the opening area of the relief hole G is not linearly changed with respect to the amount of movement of the valve body F (valve stroke), that is, the change in the opening area of the relief hole G with respect to the amount of movement of the valve body F (valve stroke) is not linear. It is not proportional to the opening degree.

As a result, the oil pressure becomes unstable, that is, the oil pressure adjustment ability becomes insufficient. Furthermore, since the relief hole G is located next to the valve body F, the oil flowing through the relief hole G applies a lateral thrust K to the valve body F, resulting in an inconvenience that the movement of the valve body F is not smooth. Furthermore, in such a relief valve, the relief hole G requires machining, which increases the number of manufacturing steps.

In addition, the spring storage part M on the back passes through the gap on the outer periphery of the valve body F.
Since oil accumulates in the valve body F and prevents movement of the valve body F, it is necessary to provide an adjustment hole P for releasing the oil in the spring support plate N forming the lower end of the spring storage part M, which complicates the structure accordingly.

This invention was made in view of the above points, and its purpose is to provide an engine relief valve that stabilizes oil pressure, eliminates the need for machining of relief holes, and has a simple structure. Our goal is to provide the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a relief oil passage downstream of the valve body with a slit-like groove that is long in the direction of movement of the valve body.

[Operation] According to the present invention, when the discharge pressure of oil discharged from the oil pump exceeds a certain value, the valve body of the relief valve moves and the oil is discharged from the slit-shaped groove. As the valve body moves, the opening area of the relief oil passage becomes larger in proportion to the amount of movement of the valve body, so that the oil pressure in the circuit becomes stable. Further, the groove can be formed by casting together with the movement path of the valve body, and there is no need to provide it later by machining. Furthermore, since the relief oil passage mentioned above also communicates with the back of the valve body, the pressure at the back of the valve body will not be greater than that at the front of the valve body, so a special oil pressure adjustment hole is required at the back of the valve body. Not.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show a first embodiment. In FIG. 1, reference numeral 11 denotes a vertical shaft type engine, and a cover 13 is fixed to the lower part of a cylinder block 12 of the engine. This cover 13 includes a drive gear 14 that is interlocked with a vertically set crankshaft or camshaft (not shown), and a trochoid-type oil pump 15 that is driven by the drive gear 14.
A suction oil passage 16, a discharge oil passage 17, and a relief oil passage 18 are formed inside the cover 13, and a relief valve 19 is provided in the relief oil passage 18.

The relief valve 19 has a valve body 20 made of a ball, and a spring body 21 that controls the opening degree of the valve body 20, and this spring body 21 is housed inside a spring chamber 22.
It is inserted between the pump cover 24 forming one side wall of the oil pump 15 and the valve body 20 .

Further, the relief oil passage downstream of the valve body 20 is connected to the valve body 20.
It is formed with a long slit-shaped groove 25 in the moving direction 23 of 0. As shown in FIG. 2, this groove 25 is provided in the boss portion 27 forming the spring chamber 22, and as shown in FIG. There are two placed around it at equal intervals. Therefore, as shown in FIG.
A direction 2 in which the flow is divided into the hand and perpendicular to the moving direction 23 of the valve body 20
Relief at 8.

The outlet 17a of the discharge oil passage 17 shown in FIG. 1 is led to a lubricated portion of the engine 11 through an outlet passage (not shown) formed inside the wall of the cylinder block 12.

In the above configuration, when the pressure of the oil in the discharge oil passage 17 shown in FIG. 18 is opened to relieve the oil and maintain the oil pressure in the discharge oil passage 17 at a constant value.

At this time, the relief oil passage downstream of the valve body 20 is
Since the slit groove 25 is long in the moving direction 23, as is clear from FIG.
are proportional. Therefore, as the pressure in the discharge oil passage 17 is higher, the amount of movement becomes larger, the opening area of the groove 25 increases, and the relief amount increases, so that the oil pressure in the discharge oil passage 17 is stabilized.

Further, since the groove 25 communicates with the back (upper part) of the valve body 20, when the valve body 20 is opened, the pressure at the front and back of the valve body 20 becomes the same, so the pressure at the back is adjusted. In addition, the groove 25 eliminates the need for an adjustment hole for the valve body 20.
Since the spring chamber 22 can be formed by casting, that is, the movement passage for the valve body 20 can be formed simultaneously with the formation of the movement passage for the valve body 20, and there is no need to provide it later by machining, manufacturing is easy. .

In addition, in this embodiment, the grooves 25 are arranged at equal intervals around the moving direction 23 of the valve body 20, so that the grooves 25 are arranged at equal intervals around the moving direction 23 of the valve body 20. thrusts 30 cancel each other out. Therefore, since no lateral thrust acts on the valve body 20, the valve body 20
movement is smooth.

FIG. 5 shows a second embodiment of the present invention, in which the valve body 20 has a cylindrical shape, and the relief oil passage downstream of the valve body 20 also extends in the moving direction 23 of the valve body 20. It is formed of long slit-shaped grooves 25, and as shown in FIG. 6, two grooves 25 are arranged at equal intervals around the moving direction 23 of the valve body 20. As is clear from FIG. 5, unlike the first embodiment, the oil is relieved in the moving direction 23 in the second embodiment.

Also in the second embodiment, the amount of movement of the valve body 20 and
Since the opening area S of the groove 25 is proportional, the oil pressure in the discharge oil passage 17 is stabilized.

Furthermore, since the groove 25 is formed to widen toward the moving direction 23, even when the amount of movement of the valve body 20 is large, the amount of movement of the valve body 20 and the substantial opening area of the groove 25 are As a result, the stabilization of hydraulic pressure is further promoted. In other words, as shown by the broken line in FIG. 7, if the groove 25A is straight, the area St of the upper end opening of the groove 25A is constant regardless of the amount of movement of the valve body 20. If the groove 25 has a shape that widens toward the end, as in the embodiment shown in FIG. The area S2 is proportional to the amount of movement of the valve body 20. This proportional relationship remains unchanged even when the amount of movement of the valve body 20 increases, so even if the amount of movement of the valve body 20 is large, the actual opening area S2 becomes sufficiently large in proportion to this, so that the oil pressure can be stabilized. will be realized. Of course, even if the groove 25 has a straight shape, if the area Sl of the upper end opening is sufficiently larger than the cross-sectional area S3 of the relief oil passage 18, the shape is substantially the same as a shape that widens at the end, and is included in the present invention. Become.

It goes without saying that in each of the above embodiments, three or more grooves 25 may be provided.

[Effects of the Invention] As described above, according to the present invention, the amount of movement of the valve body is proportional to the opening area of the relief oil passage, so that the oil pressure is stabilized. Further, since an adjustment hole for adjusting the pressure at the back of the valve body is not required, the structure is simplified accordingly.

Furthermore, since the grooves can be formed by casting and there is no need to provide them later by machining, manufacturing is easy.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing the first embodiment of the present invention, and the second
The figure is a plan view showing the same embodiment, FIG. 3 is a sectional view taken along the line m-■ in FIG. 1, FIG. 4 is a sectional view taken along the line IV-IV in FIG. Vertical sectional view showing the second embodiment, No. 6
The figure is a sectional view taken along the line vt-■ in Fig. 5, Fig. 7 is an explanatory diagram showing the operation of the same embodiment, Fig. 8 is a front view showing the conventional example, and Fig. 9 is the IX of Fig. 8. - It is a sectional view along the IX line. 15...Oil pump, 18...Relief oil path, 1
9... Relief valve, 20... Valve body, 23... Movement direction, 25... Groove.

Claims (2)

[Claims] (1) A relief valve for oil pressure adjustment leading to an engine oil pump, characterized in that the relief oil passage downstream of the valve body is formed by a long slit-shaped groove in the direction of movement of the valve body. engine relief valve. (2) The engine relief valve according to claim 1, wherein a plurality of the slit-shaped grooves are arranged at equal intervals around the moving direction of the valve body.