JP5415234B2 - Control valve for variable displacement compressor - Google Patents

Description

  The present invention relates to a control valve for a variable displacement compressor used in a car air conditioner and the like, and in particular, a minute foreign matter (during machining and assembly) accumulated in a sliding surface gap formed between a valve rod and a guide hole. The present invention relates to a control valve that is less likely to cause a malfunction of a valve stem due to cutting abrasive scraps, abrasives, wear due to sliding friction, dust from the outside, and the like.

  In general, a control valve for a variable displacement compressor used in a car air conditioner or the like introduces a refrigerant having a discharge pressure Pd from the compressor and adjusts the discharge pressure Pd to adjust the pressure Pc in the crank chamber of the compressor. The refrigerant is squeezed out and led out to the crank chamber, and the derivation amount (throttle amount) to the crank chamber is controlled in accordance with the suction pressure Ps of the compressor. 2 and the like, a valve stem, a guide hole into which the valve stem is slidably inserted, a discharge pressure port (Pd hole) for introducing discharge pressure from the compressor, A valve body provided with a control pressure port (Pc hole) communicating with the crank chamber, a suction pressure port into which the suction pressure of the compressor is introduced, and an electromagnetic actuator for driving the valve stem in the valve opening / closing direction And responding to the suction pressure of the compressor And a sensitive 圧応 rotary members of the bellows or the like for driving the valve rod in the valve-closing direction Te.

  As such a control valve for a variable capacity compressor, the inventors of the present application have previously proposed a control valve as shown in FIG. Hereinafter, the illustrated control valve 5 will be briefly described (see also Patent Document 3 below). The illustrated control valve 5 includes a valve rod 15 integrally connected to the operation rod 14. The valve stem 15 includes an upper shaft portion 15c slidably inserted in an upper guide hole 19A provided in the valve body 20, a small diameter shaft portion 15b having a smaller diameter than the upper shaft portion 15c, and a larger diameter than the upper shaft portion 15c. The same diameter as the upper shaft portion 15c slidably inserted into the valve body portion 15a having a diameter and the cylindrical body 52 (lower guide hole 19B) inserted and fixed to the lower end portion of the valve body 20. It has a lower shaft portion 15e. A lower end portion (concave hole portion) 14b of the operating rod 14 is connected and fixed to the upper portion (convex portion) of the valve rod 15 by press fitting or the like, and an annular groove portion (small diameter portion) 15d is provided below the connection fixing portion. At the same time, a locking portion 38 provided at the bottom of the plunger 37 is fitted into the annular groove 15d so that the valve stem 15 and the plunger 37 can be moved up and down integrally.

  On the other hand, the valve main body 20 has a valve chamber 21 provided with a valve port (valve seat portion) 22 with which the valve body portion 15a is brought into contact with and separated from the valve body portion 15a, and an upper shaft portion of the valve rod 15 above the valve port 22. An upper guide hole 19A into which 15c is slidably inserted is provided, and a lower shaft portion 15e of the valve rod 15 is defined below the valve port 22 so as to define a lower surface of the valve chamber 21. A cylindrical body 52 having a lower guide hole 19B into which is slidably fitted is press-fitted and fixed.

  A discharge pressure port (Pd hole) 25 having a circular cross section for introducing the discharge pressure Pd from the compressor is provided in the lower valve chamber 21 across the valve port 22 in the valve body 20. Two Pd holes 25 are arranged opposite to each other with an interval of 180 degrees.

  Further, on the upper side across the valve port 22 in the valve body 20, a control pressure port (Pc hole) 26 for controlling Pc communicates with the crank chamber (pressure Pc) of the compressor. Two are arranged opposite to each other with an interval (provided so as to cross through the valve body 20). The Pc holes 26 are circular in cross section, and their inner ends are opened to the lower part (Pc chamber 26S) of the upper guide hole 19A.

  More specifically, as shown in schematic enlarged views (exaggerated dimensions and shapes) in FIGS. 5 and 6, between the upper shaft portion 15 c and the small diameter shaft portion 15 b in the valve stem 15, In order to reduce these steps, an inverted truncated cone-shaped step reducing portion 15v and a flat surface portion 15u are provided. The diameter of the lower surface of the step reducing portion 15v is the same as that of the small-diameter shaft portion 15b, the diameter of the upper surface is slightly smaller than the upper shaft portion 15c, and the upper surface of the step reducing portion 15v and the outer peripheral surface of the upper shaft portion 15c. The space is a flat surface portion 15u. Further, an annular sliding surface gap γ [passage cross-sectional area (horizontal cross-sectional area) Sr] is formed between the upper guide hole 19A and the upper shaft portion 15c, and the upper guide hole 19A (the inner peripheral surface thereof). And a small diameter shaft portion 15b, a step reducing portion 15v, and a flat surface portion 15u, a Pc chamber 26S is formed. The center line Oc of the Pc hole 26 is located near the lower surface of the step reducing portion 15v, and the diameter of the Pc hole 26 extends from the center of the small diameter shaft portion 15b to the center of the step reducing portion 15v.

  On the other hand, a suction pressure introduction chamber 72 (same diameter as the lower guide hole 19B) into which the suction pressure Ps is introduced is provided at the lower end portion of the lower guide hole 19B in the cylindrical body 52, and the valve body 20 is provided with the same. In order to guide the suction pressure Ps to the pressure sensitive chamber 45 (the bellows body 40), a suction pressure passage 70 including linear through holes (small diameter hole 70a and large diameter hole 70b) is provided. One end (upper end) of the suction pressure passage 70 communicates with the pressure sensing chamber 45 via the plunger chamber 24, and the other end is opened at the lower end portion of the valve body 20.

  The control valve 5 having such a configuration is assembled into a valve mounting hole (stepped hole) 80 formed in the vicinity of the swash plate chamber in the body housing 100 of the variable capacity compressor. A snap ring (C-shaped ring) 81 for preventing removal is attached to the upper part of the valve mounting hole 80, and this snap ring 81 is brought into contact with the upper end portion (caulking portion) 62 of the housing 60. The airframe housing 100 has a Pd hole 25, a Pc hole 26, and a Ps passage 92, a Pc passage 93, and a Ps passage 91 communicating with a Ps introduction chamber 88, a suction pressure port 72, and a suction pressure passage 70, which will be described later. Is provided. In addition, O-rings 82, 83, and 84 are arranged at important points between the outer peripheral surface of the control valve 5 and the inner peripheral surface of the valve mounting hole 80 so that Pd, Pc, and Ps do not leak. .

  A Ps introduction chamber 88 is provided between the bottom (lower part) of the valve mounting hole 80 and the lower end of the valve body 20, and the suction pressure Ps introduced into the Ps introduction chamber 88 via the Ps passage 91 is the suction pressure. The pressure port 72 is a force that pushes up the valve rod 15 in the valve closing direction, and a force that is guided to the plunger chamber 24 through the suction pressure passage 70 and pushes down the valve rod 15 in the valve closing direction.

In the control valve 5 having such a configuration, the following forces are respectively applied in the valve opening direction (downward) and the valve closing direction (upward) by the pressure of the refrigerant acting on the valve rod 15. That is, the cross-sectional area of the upper shaft portion 15c of the valve stem 15 (the portion sliding on the upper guide hole 19A) is Sa, the effective opening area of the valve port 22 is Sb, and the lower shaft portion 15e of the valve stem 15 (lower guide) If the cross-sectional area of the portion sliding the hole 19B) is Sc, the discharge pressure is Pd, the suction pressure is Ps, and the crank chamber pressure is Pc,
Force applied in the valve opening direction = Pd x Sc + Pc x Sb + Ps x Sa
Force applied in valve closing direction = Pd x Sb + Pc x Sa + Ps x Sc
It becomes.

  Here, since the cross-sectional area Sa of the upper shaft portion 15c, the effective opening area Sb of the valve port 22, and the cross-sectional area Sc of the lower shaft portion 15e are substantially the same in design, Pd × Sc = Pd × Sb Pc × Sb = Pc × Sa and Ps × Sa = Ps × Sc, and the force applied in the valve opening direction = the force applied in the valve closing direction.

  In this way, the present control valve 5 is provided with the suction pressure port 72 into which the suction pressure Ps is introduced at the lower end portion of the lower guide hole 19B, and the suction pressure Ps acts on the lower end surface of the valve stem 5. In addition, since the valve body 20 is provided with a suction pressure passage 70 for guiding the suction pressure Ps to the pressure sensing chamber 45, the upper shaft portion 15c and the lower shaft portion 15e of the valve stem 15 and the valve port 22 are disconnected. If the areas Sa, Sc, and Sb are the same, the force applied in the valve opening direction and the force applied in the valve closing direction due to the discharge pressure Pd and the crank chamber pressure Pc acting on the valve stem 15 are made the same (offset), and The force applied in the valve opening direction due to the suction pressure Ps acting on the valve stem 15 and the force applied in the valve closing direction are also made the same (cancelled). As a result, the force in the valve opening direction due to the refrigerant pressure applied to the valve stem 15 and the valve closing Because the direction force is the same, it acts on the valve stem 15 It less susceptible to adverse effects on the control by the medium pressure.

JP 2002-303262 A JP 2007-205248 A Japanese Patent Application No. 2009-028080

  In the control valve 5 as described above, when the valve body portion 15a opens the valve port 22, Pd> Ps and Pc> Ps are satisfied, so that the valve chamber 21 is changed to the Pc chamber 26S as shown in FIG. Of the introduced refrigerant, most of the refrigerant facing the Pc hole 26 has a smaller cross-sectional area of passage formed between the upper guide hole 19A and the upper shaft portion 15c than the sliding surface gap γ side. Although flowing to the Pc hole 26 side, as shown in FIG. 6, a part of the refrigerant not facing the Pc hole 26 is formed between the upper shaft portion 15c of the valve stem 15 and the upper guide hole 19A. It will flow into the sliding surface gap γ. At this time, minute foreign matters M (cutting scraps, abrasives, wear due to sliding friction, dust from the outside, etc.) remaining in the refrigerant accumulate in the flat surface portion 15u and the sliding surface gap γ. Even if the sliding surface gap γ is clogged, the sliding resistance of the valve stem 15 increases and the valve stem 15 malfunctions. For example, even if the suction element 34 generates a normal suction force, the valve stem 15 A situation that does not move upward may occur, and in this case, the valve opening is not adjusted appropriately. Actually, the minute foreign matter that causes such a problem cannot be completely removed even if a filter or the like is provided.

  The present invention has been made in view of the above circumstances, and the object of the present invention is that minute foreign matters do not accumulate in the sliding surface gap formed between the valve stem and the guide hole, particularly in the periphery of the Pc hole. Accordingly, it is an object of the present invention to provide a control valve for a variable displacement compressor that can prevent the malfunction of the valve stem caused by minute foreign matters.

In order to achieve the above object, a control valve for a variable displacement compressor according to the present invention basically includes an upper shaft portion, a small diameter shaft portion having a smaller diameter than the upper shaft portion, and the upper shaft portion and the small diameter shaft. A step-reducing portion having a substantially truncated cone shape provided to reduce a step between the valve portion and a valve stem having a valve body portion having a diameter larger than that of the upper shaft portion; An upper guide hole into which the upper shaft portion of the valve rod is slidably inserted is provided above the valve opening, and the discharge pressure of the compressor is provided in the valve chamber. And a valve body having a Pc chamber in which a Pc hole communicating with the crank chamber of the compressor is opened above the valve chamber, and the valve rod is opened and closed. Electromagnetic actuator for driving in the direction, and opening and closing of the valve stem in response to the suction pressure of the compressor And a sensitive圧応dynamic member for driving the direction, the inner diameter of the Pc hole, said set larger than the inner diameter of the upper guide hole, in a cross section perpendicular to the central line Oc of the Pc hole, the valve body portion is the valve When the valve is opened away from the mouth , the intersection Qa between the step reduced portion and the upper shaft portion is located in the Pc hole, and the extension line La and the Pc hole of the outer peripheral slope of the step reduced portion The dimension shape of each part is set so that the intersection point Qb is located outside the inner peripheral surface of the upper guide hole.

In a preferred aspect, in the cross section, the intersection Qc between the outer peripheral surface of the upper shaft portion and the Pc hole, the refrigerant passing cross-sectional area Ss of the region λ connecting the intersection Qa and the intersection Qb, and the upper guide hole and the It is configured to be larger than the refrigerant passage cross-sectional area Sr formed between the upper shaft portion and the upper shaft portion.

  In a more preferred aspect, a lower guide hole into which a lower shaft portion of the valve rod is slidably fitted is provided below the valve port so that the suction pressure acts on the lower end portion of the valve rod. In addition, a suction pressure passage is provided in the valve body to guide the suction pressure to the pressure sensitive member, and a force in a valve opening direction and a force in a valve closing direction due to the refrigerant pressure applied to the valve rod are Are configured to be the same.

  In the control valve for a variable capacity compressor according to the present invention, the refrigerant facing the Pc hole of the refrigerant introduced into the Pc chamber passes through the upper guide hole and the upper shaft portion. The cross-sectional area flows toward the Pc hole side rather than the sliding surface gap γ side. On the other hand, as shown in FIG. 3, the refrigerant not facing the Pc hole also passes through the intersections Qa, Qb and the region λ connecting the Qc, rather than the cross-sectional area Sr of the sliding surface gap γ. By increasing the cross-sectional area Ss, it becomes easier to flow to the Pc hole side than to the sliding surface gap γ side.

  For this reason, it is possible to prevent the minute foreign matter from accumulating in the sliding surface gap γ formed between the upper shaft portion and the upper guide hole, particularly in the periphery of the Pc hole. As a result, the valve stem caused by the minute foreign matter is prevented. It is difficult to cause malfunction and the like.

BRIEF DESCRIPTION OF THE DRAWINGS One Embodiment of the control valve for variable displacement compressors which concerns on this invention is shown, (A) is a top view, (B) is sectional drawing which follows the YY arrow line of (A). The model enlarged view around Pc hole in FIG. The model enlarged view of Pc hole periphery of the state rotated 90 degree | times with respect to FIG. An example of the conventional control valve for variable capacity compressors is shown, (A) is a top view, (B) is sectional drawing which follows the YY arrow line of (A). The model enlarged view around Pc hole in FIG. FIG. 6 is a schematic enlarged view around a Pc hole in a state rotated 90 degrees with respect to FIG. 5.

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

  1A and 1B show an embodiment of a control valve for a variable displacement compressor according to the present invention, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line YY in FIG. In the variable displacement compressor control valve 1 shown in FIG. 1, the parts corresponding to the parts of the control valve 5 shown in FIG. 4 to FIG. In the following, the differences will be described mainly.

  In the control valve 1 of the illustrated embodiment, an inverted frustoconical step reducing portion 15v is provided between the upper shaft portion 15c and the small diameter shaft portion 15b of the valve stem 15 in order to reduce those steps. The conventional flat control portion 5u does not exist in the conventional control valve 5. In addition to FIG. 1, see FIG. 2 (a schematic enlarged view around the Pc hole 26 in FIG. 1) and FIG. 3 (a schematic enlarged view around the Pc hole 26 in a state rotated 90 degrees with respect to FIG. 2). As can be clearly understood, the diameter of the Pc hole 26 is made larger than that of the conventional example.

  Specifically, when viewed in a cross section (FIG. 3) perpendicular to the center line Oc of the Pc hole, the intersection Qa between the step reduced portion 15v and the upper shaft portion 15c is located in the Pc hole 26, and The dimensional shape of each part is set so that the intersection Qb between the extension line La of the outer surface (slope) of the step reducing portion 15v and the Pc hole 26 is located outside the inner peripheral surface of the upper guide hole 19A.

  In the control valve 1 having such a configuration, as shown in FIG. 2, the refrigerant facing the Pc hole 26 out of the refrigerant introduced into the Pc chamber 26S is separated from the upper guide hole 19A and the upper side. The passing cross-sectional area formed between the shaft portion 15c flows toward the Pc hole 26 rather than the sliding surface gap γ. On the other hand, as shown in FIG. 3, the refrigerant not facing the Pc hole 26 also has the intersection points Qa, Qb, and Qc (the upper shaft portion in FIG. Since the passage cross-sectional area Ss by the region λ connecting the outer peripheral surface of 15c and the Pc hole 26 is larger, it flows more easily to the Pc hole 26 side than to the sliding surface gap γ side.

  For this reason, in particular, the fine foreign matter M can be prevented from accumulating in the sliding surface gap γ formed between the upper shaft portion 15c and the upper guide hole 19A in the peripheral portion of the Pc hole 26. It is possible to make it difficult to cause the malfunction of the valve stem 15 to be performed.

DESCRIPTION OF SYMBOLS 1 Control valve 15 for variable capacity type compressors Valve rod 15a Valve body part 15c Upper shaft part 15e Lower shaft part 15v Step reduction part 19A Upper guide hole 19B Lower guide hole 20 Valve body 21 Valve chamber 22 Valve port (valve seat) Part)
25 Pd hole 26 Pc hole 26S Pc chamber 30 Electromagnetic actuator 40 Bellows body

Claims (3)

An upper shaft portion, a small-diameter shaft portion having a smaller diameter than the upper shaft portion, a step-reducing portion exhibiting a substantially truncated cone shape provided to reduce a step between the upper shaft portion and the small-diameter shaft portion, and the upper side A valve stem having a valve body portion having a diameter larger than that of the shaft portion, and a valve chamber provided with a valve port for contacting and separating the valve body portion, and the upper shaft portion of the valve stem slides above the valve port. An upper guide hole that is movably inserted is provided, a Pd hole for introducing the discharge pressure of the compressor is opened in the valve chamber, and communicates with the crank chamber of the compressor above the valve chamber. A valve body provided with a Pc chamber in which a Pc hole is opened, an electromagnetic actuator for driving the valve rod in the valve opening / closing direction, and opening / closing the valve rod in response to suction pressure of the compressor A pressure-sensitive response member that drives in the direction,
The inner diameter of the Pc hole is set to be larger than the inner diameter of the upper guide hole , and when the valve body is in a valve-opened state away from the valve opening in a cross section orthogonal to the center line Oc of the Pc hole, An intersection point Qa between the reduced portion and the upper shaft portion is located in the Pc hole, and an intersection point Qb between the extension line La of the outer peripheral slope of the step reduced portion and the Pc hole is the inner peripheral surface of the upper guide hole. A control valve for a variable displacement compressor, wherein the size and shape of each part is set so as to be located on the outer side. In the cross section, the intersection point Qc between the outer peripheral surface of the upper shaft portion and the Pc hole, the refrigerant passing cross-sectional area Ss of the region λ connecting the intersection point Qa and the intersection point Qb, and the upper guide hole and the upper shaft portion. 2. The control valve for a variable displacement compressor according to claim 1, wherein the control valve is larger than a refrigerant passage sectional area Sr formed between the two.   A lower guide hole into which the lower shaft portion of the valve rod is slidably fitted is provided below the valve port, and the suction pressure acts on the lower end portion of the valve rod, The valve body is provided with a suction pressure passage for guiding the suction pressure to the pressure sensitive member so that the force in the valve opening direction and the force in the valve closing direction are the same due to the refrigerant pressure applied to the valve rod. The variable displacement compressor control valve according to claim 1 or 2, wherein the control valve is configured as follows.

Images