JP2005036883A - Double poppet type valve device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double poppet type valve device capable of improving efficiency of manufacture by assembling it easily and improving its precision as a completed product. <P>SOLUTION: When a valve shaft 22 is inserted for assembling into a valve body 14 in which valve seats 36a, 36b are formed, diameter of a valve 34a on an upper side of two valves is set to be smaller than diameter of a valve 34b on a lower side. Consequently, the valve shaft and two valves can be integrally manufactured and the valve seats can be integrally manufactured so that the valve shaft can be inserted into the valve seat using a valve side having small diameter as a tip to facilitate assembly and improve efficiency of manufacture. Since the number of parts is two, precision as the completed product can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a double poppet valve device.

The double poppet type valve is configured such that two valves are attached to the upper and lower sides of a valve shaft and are respectively seated on two corresponding valve seats formed on the valve body. Since this type of valve has two valves on the top and bottom, the force balances even if differential pressure acts on the front and back of the valve, so the valve will not open even if the valve diameter is increased to ensure the flow rate. Can be. Therefore, it is often used for EGR valves. Examples thereof include the techniques described in Patent Documents 1 and 2.
JP-A-11-182355 International Publication No. W099 / 61775

  By the way, in the double poppet type EGR valve described above, when the upper and lower valve diameters are made the same, the valve shaft and the upper and lower valves (umbrellas) are manufactured integrally, and the valve seat on the valve body side is also manufactured integrally. Can't assemble.

  Therefore, conventionally, for example, the lower half of the valve shaft and the lower valve are manufactured separately, the lower valve seat is manufactured separately from the valve body, and the upper half of the valve shaft and the upper valve are further manufactured. Was produced as one. Then, the integrated valve shaft upper half and upper valve are inserted into the valve body without the lower valve seat, then the lower valve seat is welded to the valve body, and the valve shaft lower half and lower valve are And were integrated by welding.

  Therefore, when the valve shaft is completed by welding the upper half and the lower half, or when the lower half of the valve shaft and the lower valve are welded, the shaft may be bent or the valve may be inclined. It was difficult to manufacture with high accuracy. Furthermore, since the number of parts is large, the dimensional variation of each part is accumulated, which makes it difficult to obtain the desired accuracy.

  Accordingly, an object of the present invention is to provide a double poppet type valve device that solves the above-mentioned problems and can be easily assembled to improve manufacturing efficiency and also improve accuracy as a finished product. It is in.

  In order to solve the above-mentioned object, according to claim 1, two valves are attached in the axial direction of the valve shaft and are respectively seated on two corresponding valve seats formed in the valve body. In the double poppet type valve device, the diameters of the two valves are made different.

  In the double poppet type valve device according to claim 2, the diameter of the valve located on the front end side in the insertion direction is made smaller than that located on the rear end side among the two valves. .

  In the double poppet type valve device according to claim 1, since the two valves have different diameters, the valve shaft and the two (upper and lower) valves are manufactured integrally, and the corresponding upper and lower The valve seat can be integrally manufactured, and the valve shaft can be inserted into the valve seat with the small-diameter valve side as a tip. This eliminates the need for a welding (or caulking) process, so that it can be easily assembled and manufacturing efficiency can be improved.

  In addition, since the number of parts is also two points, the valve (and the valve shaft integrated with it) and the valve seat, the accumulation of dimensional variation of each part also decreases, so the accuracy as a finished product can be improved. it can. Furthermore, as a result, the leak amount as a double poppet type valve can be reduced and the sealing performance can be improved.

  In the double poppet type valve device according to claim 2, the diameter of the valve located on the front end side in the insertion direction is made smaller than that located on the rear end side among the two valves. Therefore, the operation when inserting and assembling the valve shaft into the valve body on which the valve seat is formed is facilitated, and the above-described effects can be further improved.

  The best mode for carrying out a double poppet valve device according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is an explanatory sectional view generally showing a double poppet type valve device according to a first embodiment of the present invention, and FIG. 2 is an explanatory view schematically showing it.

  In FIG. 1, reference numeral 10 denotes a double poppet type valve device. An example of the valve device is an EGR valve device. A double poppet type valve device (hereinafter referred to as “EGR valve device”) 10 is inserted in an EGR passage (shown by an imaginary line 12) for returning exhaust gas of an internal combustion engine (not shown) to an intake system (not shown). A valve body 14 and an actuator unit 20 connected to the valve body 14 by bolts 16 are also included.

  A valve shaft 22 is accommodated inside the valve body 14 and the actuator portion 20 so as to penetrate them. The distal end side (upper side in the drawing) of the valve shaft 22 is fixed to the member 24 having a substantially H shape in cross section in the actuator portion 20 with a slight gap 24a and screwed (not shown). An electromagnetic solenoid (actuator) 26 is disposed in the vicinity of the member 24. The electromagnetic solenoid 26 includes a coil 26a and a magnetic body 26b disposed around the coil 26a.

  The electromagnetic solenoid 26 is connected to a power source (not shown) and is excited when energized to drive (pull) the member 24 (and the valve shaft 22 screwed to the member 24) in the axial direction, more specifically, downward in FIG. . A return spring (compression spring) 30 is mounted in the gap formed in the lower part of the member 24, and the member 24 (and the valve shaft 22 screwed to the member 24) is opposed to the axial direction, more specifically, FIG. Is biased upward. Reference numeral 32 denotes a bearing portion, and 32a denotes a sealing material.

  Two valves 34 a and 34 b are attached to the valve shaft 22 on the upper side close to the electromagnetic solenoid (actuator) 26 and on the lower side separated from the upper side. On the other hand, the valve body 14 is formed with two valve seats 36a and 36b corresponding to the valves 34a and 34b. Seating surfaces 34a1 and 34b1 are formed on the two valves 34a and 34b (shown well in FIG. 2).

  When the valve shaft 22 is driven in the axial direction (downward in the figure) by the excitation of the electromagnetic solenoid 26, the two valves 34a and 34b are both opened away from the valve seats 36a and 36b. As a result, as shown by the arrows in FIG. 1, the exhaust gas (EGR gas) that flows in flows out through the two valves 34a and 34b. When the electromagnetic solenoid 26 is demagnetized, the valve shaft 22 is driven in the opposite direction by the urging force of the return spring 30, and the two valves 34 a and 34 b are both seated on the valve seats 36 a and 36 b and pass through the EGR passage 12. Close.

  The EGR valve 10 is thus composed of a double poppet type valve, and is inserted into the EGR passage 12 for recirculating the exhaust gas of the internal combustion engine to the intake system and is connected to an electromagnetic solenoid (actuator) 26, and the electromagnetic solenoid of the valve shaft 22 Two valves 34a and 34b are attached to the upper side close to 26 and the lower side spaced apart from the upper side, and are seated on the corresponding two valve seats 36a and 36b formed in the valve body 14 to close the EGR passage 12 respectively. Configured as follows.

  The valve shaft 22 and the valves 34a and 34b are manufactured integrally from a stainless material. The valve seats 36a and 36b are also made of a stainless material, and are manufactured separately from the valve body 14 and fitted into the valve body 14 by an appropriate method.

  Here, the two valves 34a and 34b are configured to have different diameters. More specifically, as shown in FIG. 3, when assembling the valve body 14 in which the valve seats 36a and 36b are formed by inserting the valve shaft 22 through the opening 14a, the tip of the two valves is inserted in the insertion direction. The valve located on the side, that is, the diameter of the upper valve 34a is configured to be smaller than that located on the rear end side, that is, the diameter of the lower valve 34b (shown by a broken line in FIG. 2). ).

  As described above, in the double poppet type valve, when the upper and lower valve diameters are the same, the valve shaft 22 and the upper and lower valves 34a and 34b are manufactured integrally, and the valve body 14 side is also provided. If the valve seats 36a and 36b are also manufactured integrally, they cannot be assembled.

  Therefore, in the prior art, for example, the lower half of the valve shaft 22 and the lower valve 34b are manufactured separately, the lower valve seat 36b is manufactured separately from the valve body 14, and the valve shaft 22 is further manufactured. The upper half and the upper valve 34a are integrally manufactured. Then, the upper half of the integrated valve shaft and the upper valve 34a are inserted into the valve body 14 without the lower valve seat 36b, and then the lower valve seat 34b is welded to the valve body 14 and the lower half of the valve shaft. The part and the lower valve 34b are assembled by welding or the like.

  Therefore, when the valve shaft 22 is completed by joining the upper half and the lower half by welding or when the lower half of the valve shaft and the lower valve are welded, the shaft 22 is bent or the valve 34 is inclined. Inconveniences such as this occurred, and it was difficult to manufacture with high accuracy. Furthermore, since the number of parts is large, the dimensional variation of each part is accumulated, which makes it difficult to obtain the desired accuracy.

  Therefore, the double poppet valve device 10 according to this embodiment is configured such that the diameters of the two valves 34a and 34b are different. Thereby, as described above, the valve shaft 22 and the two (upper and lower) valves 34a and 34b can be manufactured integrally, and the corresponding upper and lower valve seats 36a and 36b can be manufactured integrally. As shown in FIG. 3, the valve shaft 22 can be inserted into the valve seat with the small-diameter valve 34a side as a tip. As a result, a welding (or caulking) process is not required, so that assembly can be easily performed and manufacturing efficiency can be improved. After assembly, the opening 14a formed in the valve body 14 is closed with a lid 14b as shown in FIG.

  In addition, since the number of parts becomes two points of the valves 34a and 34b (and the valve shaft 22 integrated with the valves 34a and 34b) and the integrated valve seats 36a and 36b, the accumulation of dimensional variations of the respective parts also decreases. The accuracy as a finished product can also be improved. Furthermore, as a result, the leak amount as the double poppet type valve device 10 can be reduced and the sealing performance can be improved. This is particularly beneficial when used as an EGR valve device, as in this embodiment.

  Further, at least one of the seating surfaces 34a1 and 34b1 of the two upper and lower valves 34a and 34b and the two valve seats 36a and 36b corresponding thereto, more specifically, the seating surfaces 34a1 and 34b1. The coating material 40 is applied to 34b1 (for convenience of understanding, the coating material 40 is exaggerated in FIG. 1).

  To explain this, as described above, the double poppet valve device 10 balances the force even if differential pressure acts on the front and back of the valve. Although it is possible and beneficial, there is a problem that one of the upper and lower valves 34a and 34b cannot be closed due to variations in processing accuracy. Similar problems may occur when the materials of the valve 34 (and the valve shaft 22) and the valve seat 36 are different and the linear expansion coefficients are different, or when there is a temperature difference between them.

  Therefore, in the EGR valve device according to this embodiment, the coating material 40 is applied to the seating surfaces 34a1 and 34b1 of the two upper and lower valves 34a and 34b. As a result, one of the two upper and lower valves 34a, 34b is seated on the corresponding valve seat due to variations in processing accuracy, a difference in the linear expansion coefficient of the material, or a temperature difference. Even if there is a clearance between the valve and the corresponding valve seat, the upper and lower two valves 34a and 34b move while collapsing the coating material 40 toward the valve seats 36a and 36b. It is possible to seal with the applied coating material 40. Therefore, while having a simple structure, the sealing performance can be improved and the leakage of EGR gas (exhaust gas) can be effectively prevented.

  In terms of this variation in machining accuracy, in the case of a double poppet type valve, as shown in FIG. 2, there are two seat portions 42 at the top and bottom. Such sealing performance must be sacrificed. Therefore, in this embodiment, priority is given to the sealing property of the valve 34a on the upper side, that is, the side close to the electromagnetic solenoid (actuator) 26 that drives the valve, and the lower side, that is, the side away from the electromagnetic solenoid 26. It was decided to perform dimensional control so as to sacrifice that of the valve 34b. Thereby, the heat damage of the electromagnetic solenoid 26 by the leaked EGR gas or the intrusion of the leaked EGR gas into the electromagnetic solenoid 26 can be suppressed. In this case, however, the clearance at the lower valve 34b must be allowed, so that the coating material 40 is applied to the seating surfaces 34a1 and 34b1 of the upper and lower valves 34a and 34b as described above. I did it.

  Furthermore, the coating thickness of the coating material 40 is made different between upper and lower, more specifically, the coating thickness of the coating material 40 on the seating surface 34b1 of the lower valve 34b is made thicker than that of the upper side (34a1). Configured. More precisely, the coating thickness of the coating material 40 on the seating surface 34b1 of the lower valve 34b is set to 30 μm, for example, while that on the upper side (34a1) is set to 10 μm and the lower coating thickness is set to that on the upper side. It was configured to be thicker than that. Thereby, the sealing performance at the lower valve 34b can be further ensured.

  In this case, even if the coating material deteriorates due to heat or the like and melts, at least the upper valve 34a can ensure the desired sealing performance. Intrusion of EGR gas into the gas can be prevented.

Further, when the EGR gas component contains an adhesive substance, it may adhere to the valve seats 36a and 36b and cause sticking of the valve (defective opening), but the coating material 40 has non-adhesiveness. By adopting the material, such inconvenience can be solved to some extent. For example, when molybdenum disulfide (MoS ₂ ) is used as a coating material, the water repellency is high, so that such substances can be prevented from adhering to some extent, and the heat resistance is relatively high. There is an advantage that it is difficult to melt.

  When molybdenum disulfide is used as the coating material, specifically, an appropriate solvent is added to the molybdenum disulfide crystal and applied in a liquid state.

  Molybdenum disulfide is an example, and any material may be used as long as it is excellent in water repellency (or non-adhesiveness) and heat resistance, such as Teflon (registered trademark), fluorine, and graphite. Conceivable.

  Since this embodiment is configured as described above, the valve shaft 22 and the two (upper and lower) valves 34a and 34b can be manufactured integrally, and the corresponding upper and lower valve seats 36a and 36b can be manufactured integrally. The valve shaft 22 can be inserted into the valve seat with the small-diameter valve 34a side as a tip. As a result, a welding (or caulking) process is not required, so that assembly can be easily performed and manufacturing efficiency can be improved.

  In addition, since the number of parts is two points, that is, the valves 34a and 34b (and the valve shaft 22 integrated with the valves 34a and 34b) and the integrated valve seats 36a and 36b, the accumulation of dimensional variations of the respective parts also decreases. The accuracy as a finished product can also be improved. Furthermore, as a result, the leak amount as the double poppet type valve device 10 can be reduced and the sealing performance can be improved. This is particularly beneficial when used as an EGR valve device, as described in this example.

  Furthermore, since the coating material 40 is applied to the seating surfaces 34a1 and 34b1 of the upper and lower two valves 34a and 34b, the sealing performance can be improved and the EGR gas (exhaust gas) can be achieved with a simple structure. ) Leakage can be effectively prevented.

  As described above, in the first embodiment of the present invention, two valves 34a and 34b are attached in the axial direction of the valve shaft 22, and two corresponding valve seats 36a and 36b formed on the valve body 14 are provided. In the double poppet type valve device 10 that is respectively seated on the two, the diameters of the two valves 34a and 34b are made different.

  The two valves 34a. In 34b, the diameter of the valve 34a located on the front end side in the insertion direction is made smaller than that located on the rear end side (diameter of the valve 34b).

  Further, two are inserted in the EGR passage 12 for returning the exhaust gas of the internal combustion engine to the intake system and connected to the actuator (electromagnetic solenoid) 26, and two on the valve shaft 22 on the upper side close to the actuator and on the lower side separated from the actuator. In the double poppet type EGR valve device, the EGR passages are closed by attaching the valves 34a and 34b of the first and second seats to the corresponding two valve seats 36a and 36b formed on the valve body 14, respectively. The coating material 40 is configured to be applied to at least one of the four locations including the upper and lower two valve seating surfaces 34a1 and 34b1 and the corresponding two valve seats 36a and 36b.

  In addition, the coating material 40 was applied at at least two locations on the top and bottom, and the coating thickness was made to be different between the top and bottom.

  In the above-described embodiment, the EGR valve device has been described as an example. However, the present invention is not limited to this, and any valve can be applied as long as it is a double poppet valve device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory cross-sectional view showing an entire EGR valve device as an example of a double poppet valve device according to a first embodiment of the present invention. Similarly, it is explanatory drawing which shows typically the double poppet type valve apparatus which concerns on 1st Example. Similarly, it is explanatory drawing which shows typically the assembly of the double poppet type valve apparatus which concerns on 1st Example.

Explanation of symbols

10 Double poppet type valve device (EGR valve device)
12 EGR passage 14 Valve body 20 Actuator part 22 Valve shaft 26 Electromagnetic solenoid (actuator)
34a, 34b Valve 34a1, 34b1 Seating surface 36a, 36b Valve seat 40 Coating material

Claims (2)

  In a double poppet type valve device in which two valves are attached in the axial direction of the valve shaft and are respectively seated on two corresponding valve seats formed on the valve body, the diameters of the two valves are A double poppet type valve device characterized by being different. The double poppet type valve device according to claim 1, wherein a diameter of a valve located on a front end side in the insertion direction is smaller than that located on a rear end side of the two valves.

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