JP2001342970A - Valve tightening structure of piston type high-pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve tightening structure of a piston type high-pressure pump capable of stably maintaining the tightened state of a high-pressure part even when a single cylinder pump vibrates by preventing a ring 35 uniformly assuring a high-pressure oil tightness from loosening by the tightening of a reed valve 8 in the circumferential direction. SOLUTION: To provide a ring-looseness preventing mechanism 36 increasing a frictional resistance installed between a ring 35 as a tightening member allowing the tightening operation of the reed valve 8 in the circumferential direction and a bracket 32, the ring 35 threadable into a pump housing 31 is provided so that the read valve 8 can be pressed against the pump housing 31 through a piston barrel 33, and the ring-looseness preventing mechanism 36 capable of preventing the ring 35 from loosening is installed between the ring 35 and the bracket 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve fastening structure for a piston-type high-pressure pump, and more particularly to a piston-type high-pressure piston with improved fastening structure of a pressure-feeding valve in a gasoline or other low-viscosity fuel pump or other fluid pump. The present invention relates to a valve fastening structure for a pump.

[0002]

2. Description of the Related Art A conventional valve fastening structure of a piston type high pressure pump is disclosed in, for example, Japanese Patent Application Laid-Open No. H11-210598.
The high-pressure fuel supply pump according to No. 1 will be outlined based on FIG. FIG. 6 is a longitudinal sectional view of the high-pressure fuel supply pump 1. The high-pressure fuel supply pump 1 includes a casing 2, a bracket 3, a tappet 4, a driving cam 5, a first plate 6, and a second plate 6. Plate 7, reed valve 8,
Piston sleeve 9, piston 10, bellows sleeve 11, bellows 12, and cylindrical fastening member 13
And

The casing 2 has a fuel inlet 14 and a fuel outlet 15 formed therein, and communicates with a suction valve 16 and a discharge valve 17 formed in the reed valve 8, respectively. The casing 2 includes a first plate 6, a reed valve 8 and a second plate 7, a piston sleeve 9 and a piston 10, and a bellows sleeve 1 in a cylindrical accommodation portion 2 </ b> A.
1 and the fastening member 13 are accommodated.

The bracket 3 is attached to the casing 2 by tightening bolts 18 uniformly arranged in the circumferential direction, and the tappet 4
Is held so that it can appear.

[0005] The tappet 4 has a tappet roller 19 and is, for example, a drive cam 5 driven to rotate by an engine.
The piston 10 reciprocates in the piston sleeve 9 in the vertical direction in FIG. A tappet spring 20 seated on the bellows sleeve 11 urges the tappet 4 downward in the figure.

A first plate 6 and a second plate 7
The reed valve 8 is tightened and fixed by a tightening action of the tightening member 13 via the piston sleeve 9 and the bellows sleeve 11 therebetween. The piston sleeve 9 accommodates the piston 10 in a reciprocating manner in the fuel pressure chamber 21 and urges the piston 10 downward in the figure by a piston spring 22.

The bellows sleeve 11 is located between the piston sleeve 9 and the tightening member 13. The bellows 12 accommodates fuel leaked from between the piston sleeve 9 and the piston 10 therein, and allows the fuel to flow back to a low pressure side from a required leak passage (not shown).

[0008] The cylindrical fastening member 13 is
By screwing this at the outermost peripheral portion of the cylindrical housing portion 2A of the casing 2 upward in the drawing, through the bellows sleeve 11 and the piston sleeve 9 (the fixing portion 9A of the piston sleeve 9). First
The reed valve 8 is tightened with a predetermined tightening force between the plate 6 and the second plate 7 to improve the high-pressure oil tightness of the reed valve 8 and prevent leakage of high-pressure fuel from this portion. Since the tightening member 13 is cylindrical, the tightening force is made uniform in the circumferential direction of the piston sleeve 9 and the surface pressure, deformation or fretting of the fastening portion (the fixing portion 9A of the piston sleeve 9) is made uniform. Can be. Further, a circumferential slit 9C is formed in the piston sleeve 9 on the outer peripheral side of the base end of the cylinder portion 9B (between the fixed portion 9A and the cylinder portion 9B). It is possible to prevent deformation of the cylinder portion 9B due to such axial force.

In the high-pressure fuel supply pump 1 having such a configuration, the tappet 4 reciprocates the piston 10 in the piston sleeve 9 via the tappet roller 19 by the rotational drive of the drive cam 5, and the tappet 4 from the suction valve 16 of the reed valve 8. And discharge from the discharge valve 17.

In assembling the high-pressure fuel supply pump 1, the first plate 6, the reed valve 8 and the second plate 7 are accommodated in the cylindrical accommodation portion 2A of the casing 2, and the piston 10 and the piston spring 22 are accommodated. The piston sleeve 9 (fixed portion 9B) in a state of being pressed is applied to the second plate 7, and the bellows sleeve 11
Is screwed in, and tightened in the direction of the casing 2. Next, the tappet spring 20, the tappet 4 and the bracket 3 are assembled and fixed with the fastening bolts 18.

However, even if the piston sleeve 9 and the bellows sleeve 11 are tightened by the tightening member 13, the high-pressure fuel supply pump 1
It is difficult to completely suppress the generation of pulsation, and there is a possibility that the tightening member 13 may be loosened due to the vibration accompanying the operation, and the tightening structure of the reed valve 8 lacks stability and reliability. .

Further, although a slit 9C is formed to prevent deformation of the cylinder portion 9B of the piston sleeve 9, it is undeniable that the mechanical strength of the cylinder portion 9B is reduced by the formation of the slit 9C. There's a problem.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a structure in which a high axial oil-tightness is obtained by tightening a reed valve around a circumferential direction to maintain a constant axial force balance. It is an object of the present invention to provide a valve fastening structure for a piston-type high-pressure pump capable of ensuring uniform pressure.

Further, the present invention prevents the ring which can be tightened around the circumferential direction of the reed valve from being loosened, and stably tightens the high-pressure portion even if there is vibration in a single cylinder pump or the like. An object of the present invention is to provide a valve fastening structure for a piston-type high-pressure pump that can be maintained.

Another object of the present invention is to provide a valve fastening structure for a piston-type high-pressure pump capable of maintaining a tightened state of a ring as a tightening member with a simple configuration.

The present invention also provides a piston-type high-pressure pump which can avoid deformation of a piston barrel in which a piston reciprocates within a tightening structure by a ring and which does not reduce mechanical strength of the piston barrel. An object of the present invention is to provide a valve fastening structure.

[0017]

That is, the present invention is to stabilize a mounting state between a ring and a bracket as a tightening member capable of performing a circumferential tightening operation of a reed valve. It focuses on providing a ring loosening prevention mechanism for increasing the frictional resistance between the pump housing, a piston barrel attached to the pump housing, and a fluid suction device provided between the piston barrel and the pump housing. A reed valve formed with a valve and a discharge valve, a piston for sucking and discharging fluid from the suction valve and the discharge valve by reciprocating in the piston barrel, and a tappet for driving the piston. A holding bracket, and a valve fastening structure for a piston type high pressure pump having A ring that can be screwed into the pump housing so as to press the reed valve against the pump housing via the piston barrel, and that the ring can be prevented from loosening between the ring and the bracket. A valve fastening structure for a piston-type high-pressure pump, comprising a ring locking mechanism.

The ring loosening prevention mechanism can be constituted by pressing a press contact portion formed at a lower portion of the ring into a press contact portion formed at an inner peripheral portion of the bracket.

The ring loosening prevention mechanism is arranged such that, in the diametrical direction of the ring, the press-contact protruding portion formed on the inner peripheral portion of the bracket is located on the inner peripheral side of the press-contact protruding portion formed below the ring. Can be

The ring has a leak space provided between the inner wall surface of the cylindrical housing portion of the pump housing and the reed valve via the piston barrel on the inner peripheral side of the leak space. It can be tightenable.

The ring may be made of steel, and the bracket may be made of aluminum.

In the valve fastening structure of the piston type high pressure pump according to the present invention, a ring loosening prevention mechanism is interposed between the bracket and the ring which can be screwed into the pump housing so as to press the reed valve against the pump housing via the piston barrel. As a result, the ring can be prevented from coming off in the axial direction even if there is vibration due to the driving of the high-pressure pump, and a stable fastening structure can be achieved. Furthermore, if a reed valve can be tightened on the inner peripheral side of the leak space with a leak space provided between the inner wall surface of the cylindrical housing of the pump housing and the piston barrel, the piston barrel reciprocates the piston. The deformation of the cylinder part can be reduced as much as possible, and the mechanical strength can be prevented from lowering.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a valve fastening structure of a piston type high pressure pump according to a first embodiment of the present invention will be described with reference to FIGS. However, the same parts as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a longitudinal sectional view of a piston type high pressure pump 30 employing a valve fastening structure.
Pump housing 31, bracket 32, tappet 4, drive cam 5, first plate 6 and second plate 7, reed valve 8, piston barrel 33
A piston 10, a bellows sleeve 34, a bellows 12, a cylindrical ring 35, a ring locking mechanism 36, a low pressure damper 37, a high pressure damper 38,
A valve fastening structure 39.

The pump housing 31 has a fuel inlet 14 and a fuel outlet 15 formed therein, and communicates with the suction valve 16 and the discharge valve 17 of the reed valve 8, respectively. Further, the cylindrical housing portion 31A is provided in the pump housing 31.
An annular leak space 40 and a housing leak passage 41 communicating with the housing are formed.

The bracket 32 is made of an aluminum material, is attached to the pump housing 31 by a fastening bolt 18, and holds the tappet 4 at its lower end so as to be able to protrude and retract.

The tappet 4 has a tappet roller 19 and reciprocates the piston 10 in the piston barrel 33 by receiving a driving force from a driving cam 5 rotated and driven by an engine.

The piston barrel 33 is provided in the fuel pressure chamber 21
The piston 10 is reciprocally accommodated therein, and the piston 10 is urged downward by a piston spring 22 in the figure.

The bellows sleeve 34 is located between the piston barrel 33 and the cylindrical ring 35. The bellows 12 accommodates therein fuel leaked from between the piston barrel 33 and the piston 10, and has a first axial leak passage 42 between the piston barrel 33 and the bellows sleeve 34, and a diameter of the bellows sleeve 34. Directional leak passage 43, furthermore, piston barrel 33 and ring 3
5, the annular leak space 40 and the housing leak passage 4
From 1 this can be returned to the low pressure side.

FIG. 2 is an enlarged longitudinal sectional view of a main part of the ring loosening prevention mechanism 36 (portion II in FIG. 1). The ring 35 is made of carbon steel or other steel material. Male screw part 3 which engages with part 31B
5A, a screw structure is formed between the pump housing 31 and the pump housing 31, and a step 35B for tightening on the inner peripheral side and a press contact part 35C having at least a part of the outer peripheral side having a slightly larger diameter are provided. The upper surface of the tightening step 35B is in contact with the lower surface of the tightening step 34A of the bellows sleeve 34 via the copper gasket 45, and the tightening step 34 is formed.
The upper surface of A further contacts the lower surface of the tightening step 33A of the piston barrel 33, and the second plate 7, the reed valve 8 and the first plate 6 are pumped by screwing the ring 35 in the axial direction. A predetermined pressure is applied to the innermost inner wall surface of the cylindrical housing portion 31A of the housing 31 to enable the reed valve 8 to be tightened, thereby ensuring high-pressure oil tightness in this portion.

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2. The ring loosening prevention mechanism 36 is provided between the above-described ring 35 and the bracket 32. As shown in FIG. 2 and FIG.
5C is in pressure contact with the axially inner peripheral wall surface 32B (pressure contact portion) of the pressure contact step portion 32A of the bracket 32 at a predetermined pressure. The press-contact portion 35C of the ring 35 made of a steel material presses or bites into the axial inner peripheral wall surface 32B of the bracket 32 made of a softer aluminum material, thereby preventing the ring 35 from being loosened in the circumferential direction, and thus the shaft 35 The directional clamping force can be maintained at a predetermined level.

As shown in FIGS. 2 and 3, the unevenness of the press-contact portion 35C of the ring 35 and the press-contact step portion 32A of the bracket 32 or the axially inner peripheral wall surface 32B is opposite to the illustrated example. There may be. That is, the press contact portion 35C can be a concave portion or a flat portion, and the axial inner peripheral wall surface 32B can be a convex portion or a flat portion.

The low pressure damper 37 equalizes the pressure pulsation on the suction side based on the reciprocating motion of the piston 10. The high-pressure damper 38 equalizes the pressure pulsation on the discharge side based on the reciprocation of the piston 10.

The valve fastening structure 39 includes a pump housing 31, a bracket 32, a first plate 6 and a second plate 7, and a reed valve 8 in addition to the cylindrical ring 35 and the ring locking mechanism 39 as described above. , A piston barrel 33, and a bellows sleeve 34.

The piston type high pressure pump 30 having such a configuration is
When the piston type high-pressure pump 30 is assembled in the valve fastening structure 39, the first plate 6,
The ring 3 containing the reed valve 8 and the second plate 7, the piston barrel 33 containing the piston 10 and the piston spring 22 is applied to the second plate 7, and the ring 3
5 is tightened in the direction of the pump housing 31. Next, the tappet spring 20, the tappet 4, and the bracket 32 are assembled and fixed with the fastening bolts 18.

By screwing the ring 35 into the pump housing 31, the bellows sleeve 34, the piston barrel 33, the second plate 7, the reed valve 8, and the first plate 6 are tightened. As shown, the press contact portion 35C presses against the press contact step portion 32A of the bracket 32, and the ring loosening prevention mechanism 36
Is configured. Therefore, even when the piston-type high-pressure pump 30 operates, the engagement between the ring 35 and the pump housing 31 is not loosened, and the reliability can be ensured.

Further, the ring 35 is provided with an annular leak space 40 between itself and the inner wall surface of the cylindrical housing portion 31A of the pump housing 31, and a bellows barrel is provided on the inner peripheral side of the leak space 40. 34 tightening step 3
4A, tightening step 33A of piston barrel 33, second
Since the reed valve 8 is tightened via the plate 7 and the first plate 6, the deformation of the piston barrel 33 can be minimized as well as the conventional high-pressure fuel supply pump 1 (FIG. 6). There is no need to form the slit 9C, and the mechanical strength is not reduced. Therefore, reciprocation of the piston 33 in the piston barrel 33 can be guaranteed.

FIG. 4 is an enlarged longitudinal sectional view of a main part of a ring fastening structure 50 according to a second embodiment of the present invention, and FIG.
FIG. 4 is a sectional view taken along line IV-IV of FIG.
In the zero ring loosening prevention mechanism 51, the ring 35
A protrusion 35D (pressing portion) is formed in the lower end of the hook in the shape of a hook, and a pressing protrusion 32C (pressing portion) is formed on the bracket 32 on the inner peripheral side of the protrusion 35D. The pressing projection 35D can be pressed against the pressing projection 32C from the outer peripheral side. In other words, in the press contact groove 32D formed on the inner peripheral side of the bracket 32, the press contact protruding portion 35D of the ring 35 presses and engages the press contact protruding portion 32C from the outer peripheral side to the inner peripheral direction.

In the ring fastening structure 50 or the ring loosening prevention mechanism 51 having such a configuration, the linear expansion coefficient of the aluminum material as the material of the bracket 32 is larger than the linear expansion coefficient of the steel material as the material of the ring 35.
In particular, when the temperature of the ring locking mechanism 51 increases, the rate at which the press-contact protrusion 32C expands to the outer peripheral side from the press-contact protrusion 35D increases. As a result, the function of the ring fastening structure 50 to prevent the ring 35 from loosening. It can be more reliable.

[0039]

As described above, according to the present invention, the ring loosening prevention mechanism is formed between the bracket and the ring for tightening the reed valve. It can be kept high.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a piston type high pressure pump 30 employing a valve fastening structure 39 according to a first embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view (part II in FIG. 1) of a main part of the ring loosening prevention mechanism 36;

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is an enlarged longitudinal sectional view of a main part of a ring fastening structure 50 according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line IV-IV of FIG. 4;

FIG. 6 is a longitudinal sectional view of a conventional high-pressure fuel supply pump 1.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 High-pressure fuel supply pump (FIG. 6) 2 Casing 2A Column-shaped accommodation part of casing 2 3 Bracket 4 Tappet 5 Drive cam 6 First plate 7 Second plate 8 Reed valve 9 Piston sleeve 9A Fixed part of piston sleeve 9 9B Cylinder part of piston sleeve 9 9C Circumferential slit of piston sleeve 9 10 Piston 11 Bellows sleeve 12 Bellows 13 Cylindrical fastening member 14 Suction port 15 Discharge port 16 Suction valve formed on reed valve 8 17 Formed on reed valve 8 Discharge valve 18 Tightening bolt 19 Tappet roller 20 Tappet spring 21 Fuel pressure chamber 22 Piston spring 30 Piston type high pressure pump (FIG. 1) 31 Pump housing 31A Cylindrical accommodation part of pump housing 31 31B Pump housing Female thread portion of jing 31 32 Bracket 32A Pressing step (pressing portion, FIG. 2) of bracket 32 32B Inner wall surface in the axial direction (pressing portion) of pressing step 32A of bracket 32 32C Projection portion for pressing of bracket 32 (Pressing portion, FIG. 4) 32D Groove portion for pressing of bracket 32 (FIG. 4) 33 Piston barrel 33A Tightening step of piston barrel 33 34 Bellows sleeve 34A Tightening step of bellows sleeve 34 35 Cylindrical ring 35A Ring 35 35B Step 35 for tightening the ring 35 35C Pressing portion of the ring 35 (FIG. 2) 35D Projection for pressing the ring 35 (pressing portion, FIG. 4) 36 Ring loosening prevention mechanism of the valve fastening structure 39 37 Low pressure damper 38 High pressure damper 39 Valve fastening structure of piston type high pressure pump 30 (first embodiment) 1, 2, 3) 40 Annular leak space 41 in cylindrical housing 31 </ b> A of pump housing 31 Housing leak passage 42 First axial leak between piston barrel 33 and bellows sleeve 34 Passage 43 Radial leak passage of bellows sleeve 34 44 Second axial leak passage between piston barrel 33 and ring 35 45 Copper gasket 50 Ring fastening structure of piston type high pressure pump 30 (second embodiment, FIG. 4, FIG. 5) 51 Ring loosening prevention mechanism of the ring fastening structure 50

Claims (5)

[Claims] 1. A pump housing, a piston barrel mounted on the pump housing, a reed valve provided between the piston barrel and the pump housing and forming a fluid suction valve and a discharge valve, and the inside of the piston barrel. Valve fastening of a piston-type high-pressure pump having a piston that reciprocates to suck and discharge fluid from the suction valve and the discharge valve, respectively, and a bracket that holds a tappet for driving the piston A ring capable of being screwed into the pump housing so as to press the reed valve against the pump housing via the piston barrel, and preventing the ring from being loosened between the ring and the bracket. Possible ring locking mechanism A valve fastening structure for a piston-type high-pressure pump. 2. The ring loosening prevention mechanism according to claim 1, wherein a pressure contact portion formed at a lower portion of the ring is pressed into a pressure contact portion formed at an inner peripheral portion of the bracket. A valve fastening structure for the piston-type high-pressure pump described in the above. 3. The ring loosening prevention mechanism according to claim 1, wherein the pressing projection formed on an inner peripheral portion of the bracket is located on an inner peripheral side of a pressing projection formed on a lower portion of the ring in a diameter direction of the ring. 2. The valve fastening structure for a piston type high pressure pump according to claim 1, wherein the valve is fastened. 4. The ring has a leak space between the inner wall surface of the cylindrical housing of the pump housing and a space between the ring and the reed via the piston barrel on the inner peripheral side of the leak space. The valve fastening structure for a piston type high pressure pump according to claim 1, wherein the valve can be tightened. 5. The valve fastening structure for a piston-type high-pressure pump according to claim 1, wherein the ring is formed of a steel material, and the bracket is formed of an aluminum material.