JPH1137335A - Flow control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an offset load of a spring load acting on a valve shaft. SOLUTION: A cap 47 is mounted on a washer 46 for fixing an upper edge of a valve shaft 36 to a diaphragm 43, and a lower edge part of a spring 49 stored in a negative pressure actuator 40 is received by a spring load receiving member 50. A spherical recessed part 51 formed on a central part of the spring load receiving member 50 is engaged with a spherical projecting part 48 formed on a central part of the cap 47, to support the spring load receiving member 50 in such manner that it is balanced on the spherical projecting part 48. When the eccentricity and inclination of the spring 49 exist, the spring load receiving member 50 is inclined on the spherical projecting part 48 as fulcrum corresponding to the eccentricity and inclination, to correct the eccentricity and inclination of the spring 49. Whereby the offset load can be prevented from acted on an upper edge part of the valve shaft 36 from the spring load receiving member 50, and the deterioration of the slidability of the valve shaft 36, the uneven abrasion of a bearing 35, a valve element 37 or the like, caused by the offset load, can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve having improved slidability of a valve shaft.

[0002]

2. Description of the Related Art Conventionally, for example, in an exhaust gas recirculation control valve (EGR valve), as shown in Japanese Utility Model Laid-Open Publication No. 4-79952 (see FIG. 5), a valve shaft 12 provided with a valve body 11 has been disclosed. The distal end is fixed to the center of the diaphragm 14 of the negative pressure actuator 13, and the diaphragm 14 is displaced by negative pressure supplied into the negative pressure actuator 13 so that the valve body 11 comes into contact with / separates from the valve seat 15. There is something like that. In this device, a spring 16 for pressing and biasing the diaphragm 14 is housed in a negative pressure actuator 13, and when the valve is closed, the resilient force of the spring 16 causes the valve shaft 12 to slide in the valve closing direction. ing.

In this configuration, if the spring 16 in the negative pressure actuator 13 is eccentric or inclined, an eccentric load is applied from the spring 16 to the diaphragm 14 and the valve shaft 12, and the eccentric load causes the valve shaft 12 to incline. There are drawbacks in that the slidability of the valve shaft 12 with respect to the bearing 17 is impaired, and that the bearing 17, the valve shaft 12, the valve body 11, and the valve seat 15 are partially worn and the sealing performance when the valve is closed is reduced.

[0004] As a countermeasure against this, in the above publication, the upper end of the spring 16 is received by a receiving plate 18,
A ball 20 is interposed between the ball 8 and the case 19 of the negative pressure actuator 13, and the receiving plate 18 is received and supported so as to maintain an equilibrium state with the ball 20 as a fulcrum. The receiving plate 18 is a ball 20
It can be freely tilted with the fulcrum as a fulcrum.

[0005]

However, in the above configuration, since the lower end of the spring 16 is in contact with the pressing plate 21 of the diaphragm 14, the contact position of the spring 16 with respect to this pressing plate 21 is eccentric. However, even if the receiving plate 18 is tilted with the ball 20 as a fulcrum, the offset load cannot be sufficiently corrected. Accordingly, the effect of correcting the unbalanced load is small, and the effect of preventing the slidability of the valve shaft 12 due to the unbalanced load and the uneven wear of the bearing 17, the valve body 11, and the like is insufficient. In addition, when assembling, the ball 20 can be lightly impacted.
Are easily detached from the spherical concave portion 18a of the receiving plate 18, which is troublesome to assemble, and the ball 20 on the back side of the receiving plate 18
Cannot be confirmed visually or the like, so that the spherical concave portion 18a
There is a possibility that the ball 20 that has come off may be assembled in a state of being sandwiched between the receiving plate 18 and the case 19, thereby increasing the unbalanced load.

Further, E flowing through the inside of the valve housing 22
Particulate matter such as soot contained in GR gas (PM: Partic
ulate may enter the inner peripheral side of the bearing 17 and accumulate, or deposits accumulated on the outer peripheral surface of the valve shaft 12 may enter the inner peripheral side of the bearing 17 due to sliding of the valve shaft 12. As a result, deposits accumulate on the inner peripheral surface of the bearing 17 and the sliding clearance on the inner periphery of the bearing 17 is reduced or clogged, which causes poor sliding of the valve shaft 12.

Accordingly, a first object of the present invention is to effectively prevent the slidability of a valve shaft from deteriorating due to an unbalanced load and uneven wear of a bearing, a valve body and the like, and to improve assemblability. Further, a second object of the present invention is to prevent the sliding property of the valve shaft from being deteriorated due to the entry of the deposit into the inner peripheral side of the bearing.

[0008]

According to a first aspect of the present invention, there is provided a flow control valve according to the first aspect of the present invention, wherein a spring load for receiving a diaphragm-side end of a spring member in a negative pressure actuator. The receiving member is accommodated, and the spring load receiving member is received and supported by a supporting portion provided at the distal end of the valve shaft so as to maintain an equilibrium state with the center portion as a fulcrum. In this configuration, the spring load is intensively applied to the support portion via the spring load receiving member, and is applied to the valve shaft from the support portion. At this time, if there is any eccentricity or inclination of the spring member, the spring load receiving member tilts with the support portion as a fulcrum according to the eccentricity or inclination, and corrects the eccentricity or inclination of the spring member. As a result, it is possible to prevent the bias load from acting on the supporting portion from the spring load receiving member, and to effectively prevent the slidability of the valve shaft due to the bias load and the uneven wear of the bearing, the valve body and the like. be able to. In addition, since the supporting portion can be fixedly provided at the tip of the valve shaft, unlike a conventional ball, the supporting portion does not easily come off from the tip of the valve shaft at the time of assembly. It is easy to attach and can prevent poor assembly.

In this case, as in claim 2, a cap having a spherical projection is used as the support, and this cap is arranged at the tip of the valve shaft and formed at the center of the spring load receiving member. By fitting a spherical concave portion into the spherical protrusion, the spring load receiving member may be received and supported so as to maintain an equilibrium state with the spherical protrusion as a fulcrum. By doing so, the support portion (cap having a spherical protrusion) can be separated from the valve shaft and processed with a material that is easy to process with high accuracy, and the concentric accuracy between the cap and the valve shaft and the processing accuracy of the spherical protrusion can be improved. Can be improved.

[0010] Alternatively, as in claim 3, the support portion is formed by processing a tip portion of the valve shaft into a spherical shape, and the spherical concave portion formed at the center of the spring load receiving member is formed. A configuration may be adopted in which the spring load receiving member is received and supported so as to be kept in an equilibrium state by using the support portion as a fulcrum by being fitted into the support portion. In this way, by integrating the valve shaft and the support portion, the number of parts can be reduced, and the assemblability can be further improved.

Further, a deposit reservoir may be formed inside the intermediate portion of the bearing for slidably supporting the valve shaft. In this way, even if the deposit invades the inner peripheral side of the bearing, the invading deposit can be accumulated in the deposit pool inside the intermediate portion of the bearing, and the sliding clearance on the inner peripheral surface of the bearing can be secured. As a result, it is possible to prevent the slidability of the valve shaft from being lowered due to the entry of the deposit into the inner peripheral side of the bearing.

When an oil seal member for sealing a gap between the end face of the bearing and the valve shaft is disposed on the inner end face of the bearing, a deposit is captured by the oil seal member and a deposit is formed between the oil seal member and the valve shaft. And the sliding resistance of the valve shaft may increase.

As a countermeasure, an oil seal member may be arranged on the outer end face of the bearing. In this way, the deposit that has entered the inner peripheral side of the bearing is accumulated in the deposit pool inside the intermediate portion of the bearing, and the sliding clearance on the inner peripheral surface of the bearing can be secured, and the sliding clearance is transmitted along the sliding clearance. The oil that is about to leak to the outside can be captured by the oil seal member on the outer end surface of the bearing, so that the oil can be prevented from leaking.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

[Embodiment (1)] An embodiment (1) in which the present invention is applied to an exhaust gas recirculation control valve (EGR valve) will be described below with reference to FIG. The valve housing 31 is formed in a cylindrical shape by, for example, aluminum die-casting, and is connected in the middle of an intake pipe (not shown) of a diesel engine to form a part of an intake passage. The lower part of the valve housing 31 has E
EGR pipe connecting part 32 for connecting GR pipe (not shown)
Is formed, and an annular valve seat 33 is provided in the EGR pipe connection portion 32. A bearing housing portion 34 is formed on the upper portion of the valve housing 31 so as to be located directly above the valve seat 33, and a bearing 35 is press-fitted and fixed in the bearing housing portion 34. The bearing 35 is formed of a sliding bearing metal material such as a copper-based sintered metal, and a deposit pool 39 is formed inside an intermediate portion of the bearing 35. The method of forming the deposit pool 39 is as follows.
By forming a thin portion 35a by recessing the intermediate outer peripheral portion of the bearing 35, and compressing and deforming the bearing 35 in the axial direction,
The thin portion 35a of the bearing 35 is deformed so as to be curved toward the outer periphery.

A stainless steel valve shaft 36 is slidably inserted in the bearing 35 in the vertical direction, and a stainless steel valve body 37 is fixed to the lower end of the valve shaft 36 by caulking. The valve body 37 comes into contact with / separates from the valve seat 33 as the valve shaft 36 descends / rises, and the EGR gas inflow port 33a on the inner periphery of the valve body 37 is opened and closed. An oil seal member 38 that seals a gap between a lower end surface of the bearing 35 and the valve shaft 36 is fitted to a lower end portion in the bearing housing portion 34.

On the other hand, a mounting seat 41 for mounting the negative pressure actuator 40 is integrally formed on the upper portion of the valve housing 31, and a case 42 of the negative pressure actuator 40 is fixed by caulking all around the mounting seat 41. This case 42
An outer peripheral portion of a rubber diaphragm 43 is sandwiched and fixed between the mounting diaphragm 41 and the mounting seat 41. This diaphragm 43
Is sandwiched between an upper plate 44 and a lower plate 45, penetrates the upper end of the valve shaft 36 through the center of the three members, and places a washer 46 on the upper end of the valve shaft 36 from above.
The upper end of the valve shaft 36 is fixed to the center of the diaphragm 43 by caulking the upper end of the valve shaft 36 in a state in which is inserted.

A metal cap 47 (support portion) made of SPCC or the like is disposed on a washer 46 at the upper end of the valve shaft 36.
Are formed. A spring 4 for urging the valve shaft 36 in the valve closing direction is provided inside the negative pressure actuator 40.
9 (spring member) and a metal spring load receiving member 50 such as SPCC for receiving the lower end of the spring 49 are accommodated. The spherical concave portion 51 formed at the center of the spring load receiving member 50 is The spring load receiving member 50 is received and supported so as to maintain an equilibrium state with the spherical protrusion 48 as a fulcrum. The upper end of the spring 49 is fitted into a circular convex portion 42a formed downward at the center of the case 42, and the lower end of the spring 49 is formed in the spring load receiving member 50 concentrically with the spherical protrusion 48. It is fitted to the protrusion 50a.

The operation of the EGR valve configured as described above will be described. The negative pressure in the negative pressure actuator 40 is controlled by a vacuum pump (not shown), and when the suction force of the diaphragm 43 caused by the negative pressure becomes larger than the elastic force of the spring 49, the diaphragm 43 is displaced upward.
As a result, the valve shaft 36 is pulled up and the valve body 37
Is separated upward from the valve seat 33, and the EGR gas inflow port 3
3a is opened. Thereafter, when the negative pressure in the negative pressure actuator 40 is released, the diaphragm 43 is pushed down together with the valve shaft 36 by the elastic force of the spring 49,
The valve body 37 contacts the valve seat 33, and the EGR gas inflow port 33a is closed.

In this way, when the valve shaft 36 moves up and down, the resilient force of the spring 49 is intensively applied to the spherical projection 48 of the cap 47 via the spring load receiving member 50, and Acting on the upper end of the valve shaft 36. At this time, if there is any eccentricity or inclination of the spring 49, the spring load receiving member 50 is accordingly moved to the spherical projection 48.
To correct the eccentricity and inclination of the spring 49. Thus, it is possible to prevent the bias load from acting on the spherical protrusion 48 from the spring load receiving member 50, and to transmit the spring load uniformly to the entire circumference of the upper end of the valve shaft 36 via the cap 47. As a result, the concentric accuracy between the spring load and the valve shaft 36 can be increased, the sliding hysteresis of the valve shaft 36 due to the unbalanced load and the flow rate hysteresis can be reduced, and the bearing 35, the valve body 37 and the valve seat 3 can be reduced.
Third, uneven wear such as 3 can be prevented, rattling of the valve shaft 36 and valve leakage due to uneven wear can be prevented, and durability can be improved.

At the time of assembling, the cap 47 with the spherical projection 48 is attached to the washer 4 at the tip of the valve shaft 36.
6, unlike the conventional ball, the cap 47 does not easily come off the tip of the valve shaft 36 at the time of assembling, so that the assembling property is good and the position of the cap 47 is good. It is possible to prevent assembly failure due to misalignment, and to prevent assembly failure. Moreover, the spherical projection 48
The attached cap 47 can be separated from the valve shaft 36 and processed with a material that is easy to process with high accuracy, and concentric accuracy between the cap 47 and the valve shaft 36 and processing accuracy of the spherical projection 48 can be improved.

Incidentally, particulate matter (PM: Pa) such as soot contained in the EGR gas flowing through the inside of the valve housing 31.
rticulate Matter) invades the inner peripheral side of the bearing 35,
Deposits deposited on the outer peripheral surface of the valve shaft 36 may enter the inner peripheral side of the bearing 35 due to sliding of the valve shaft 36.

As a countermeasure against this deposit, since the deposit reservoir 39 is formed inside the intermediate portion of the bearing 35, even if the deposit enters the inner peripheral side of the bearing 35, the deposited deposit is removed from the inside of the intermediate portion of the bearing 35. It can be stored in the deposit pool 39, and the sliding clearance on the inner periphery of the bearing 35 can be prevented from being reduced or clogged by the deposit. Thereby, the sliding clearance on the inner circumference of the bearing 35 can be ensured, and poor sliding of the valve shaft 36 due to the entry of the deposit into the inner circumference of the bearing 35 can be prevented.

[Embodiment (2)] In the embodiment (1), the supporting portion for receiving and supporting the spring load receiving member 50 is constituted by the cap 47 separate from the valve shaft 36, but is shown in FIG. In the embodiment (2) of the present invention, the valve shaft 36
When the upper end of the valve shaft 36 is caulked and fixed to the center of the diaphragm 43, the upper end of the valve shaft 36 is caulked in a spherical shape, so that a spherical support portion 55 is integrally formed on the upper end of the valve shaft 36. . Then, the spherical concave portion 57 formed at the center portion of the spring load receiving member 56 is fitted into the support portion 55 at the upper end of the valve shaft 36, so that the spring load receiving member 56
Are supported and supported so as to maintain an equilibrium state with the support portion 55 as a fulcrum. The other configuration is the same as that of the embodiment (1).

In this embodiment (1), by integrating the valve shaft 36 and the support portion 55, the number of parts can be reduced, and the assemblability can be further improved. In addition, the same effects as in the first embodiment can be obtained.

[Embodiment (3)] In the embodiment (1), the bearing 35 is formed of a sliding bearing metal material such as a copper-based sintered metal. However, the embodiment (3) of the present invention shown in FIG.
Then, the bearing 58 is formed of carbon graphite, and the bearing 58 is divided into two parts, and a cylindrical member 59 having the same outer diameter as that of the bearing 58 is interposed between the two parts, so that the inner peripheral side of the cylindrical member 59 is formed. A deposit reservoir 60 is formed. Then, the packing 61 and the washer 62 are attached to the peripheral edge of the upper end opening of the bearing housing portion 34, and the packing 61 and the washer 62 are fixed to the upper end of the bearing housing portion 34 by caulking the upper end of the bearing housing portion 34, The bearing 58 is retained. For other configurations,
This is the same as the embodiment (1).

In the present embodiment (3), the same effect as in the above embodiment (1) can be obtained. As the material of the bearing 58, a nonmetallic bearing material other than carbon graphite may be used, and of course, a sliding bearing metal material such as a copper-based sintered metal may be used.

[Embodiment (4)] In the embodiment (3), the oil seal member 38 for sealing the gap between the end face of the bearing 58 and the valve shaft 36 is arranged on the inner bearing end face.
Oil is prevented from leaking immediately before the bearing 58. However, in this configuration, the oil seal member 3
There is a possibility that the deposit may be caught on the inner periphery of 8 and the inner periphery of the oil seal member 38 may be clogged with the deposit, which may cause the slidability of the valve shaft 36 to decrease.

As a countermeasure against this, in the embodiment (4) of the present invention shown in FIG. 4, the oil seal member 38 is arranged on the outer bearing end face, and the oil seal member is not provided on the inner bearing end face. The other configuration is the same as that of the embodiment (3).

In the present embodiment (4), the deposit which has entered the inner peripheral side of the bearing 58 is accumulated in the deposit reservoir 60 inside the intermediate portion of the bearing 58, and the sliding clearance on the inner periphery of the bearing 58 can be secured. At the same time, it is possible to catch the oil that is about to leak out along the sliding clearance by the oil seal member 38 on the outer bearing end face,
Oil leakage can be prevented.

[Other Embodiments] In each of the above embodiments, the valve housing 31 of the EGR valve is connected in the middle of the intake pipe. However, the present invention can be applied to an EGR valve provided in the middle of the EGR pipe. Further, in each of the above embodiments, the structure may be such that no deposit pool is provided inside the intermediate portion of the bearing. Even in this case, the first object described above can be achieved. Alternatively, in each of the above embodiments, a configuration may be adopted in which the spring load receiving member and the support portion (cap) are not provided, and in this case, the above-described second object can be achieved.

In addition, the present invention is not limited to the EGR valve, but is applicable to various flow control valves using a negative pressure actuator as a drive source.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of an EGR valve showing an embodiment (1) of the present invention.

FIG. 2 is a longitudinal sectional front view of an EGR valve showing an embodiment (2) of the present invention.

FIG. 3 is a longitudinal sectional front view of an EGR valve showing an embodiment (3) of the present invention.

FIG. 4 is a longitudinal sectional front view of an EGR valve showing an embodiment (4) of the present invention.

FIG. 5 is a vertical front view of a conventional EGR valve.

[Explanation of symbols]

31 ... valve housing, 33 ... valve seat, 33a ... EGR gas inflow port, 34 ... bearing housing part, 35 ... bearing, 3
Reference numeral 6: valve shaft, 37: valve body, 38: oil seal member, 39: deposit reservoir, 40: negative pressure actuator, 42: case, 43: diaphragm, 44: upper plate, 45: lower plate, 46: washer, 47 …
Cap (support portion), 48: spherical protrusion, 49: spring (spring member), 50: spring load receiving member, 51: spherical concave surface portion, 55: support portion, 56: spring load receiving member, 57
... Spherical concave portion, 58 ... Bearing, 59 ... Cylindrical member, 60 ... Deposit pool, 61 ... Packing, 62 ... Washer.

Claims (5)

[Claims] 1. A flow control valve that opens and closes a valve element by fixing a distal end of a valve shaft supporting a valve element to a diaphragm of a negative pressure actuator, and displacing the diaphragm. A spring member disposed to urge the valve shaft; a spring load receiving member disposed in the negative pressure actuator to receive an end of the spring member on the diaphragm side; and a spring member provided at a distal end of the valve shaft. And a supporting portion for receiving and supporting the spring load receiving member so as to maintain an equilibrium state with a center portion as a fulcrum. 2. The support portion comprises a cap having a spherical projection, the cap being disposed at a tip end of a valve shaft, and a spherical concave portion formed at a center of the spring load receiving member being a spherical projection. 2. The flow control valve according to claim 1, wherein the spring load receiving member is received and supported so as to maintain an equilibrium state with the spherical protrusion as a fulcrum by being fitted in the spring. 3. The support portion is formed by processing a tip portion of the valve shaft into a spherical shape, and a spherical concave portion formed at a center portion of the spring load receiving member is fitted into the support portion. 2. The flow control valve according to claim 1, wherein the spring load receiving member is received and supported so as to maintain an equilibrium state with the support portion as a fulcrum. 4. A flow control valve in which a valve shaft supporting a valve body is slidably disposed via a bearing in a valve housing, wherein a deposit reservoir is formed inside an intermediate portion of the bearing. Flow control valve. 5. The flow control valve according to claim 4, wherein an oil seal member for sealing a gap between an end surface of the bearing and the valve shaft is disposed on an outer end surface of the bearing.