JP2008066182A - Pressure switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure switch capable of improving mounting workability of a prevention cover, of improving versatility to a connector to be connected thereto, and of reducing the number of components. <P>SOLUTION: This pressure switch 10 is provided with a diaphragm 44 mounted in a pressure chamber 28 together with a moving contact 45, and is structured to make the moving contact 45 contact and separate to/from fixed contacts 30 and 31 with pressure provided to the pressure chamber 28. The pressure switch 10 is provided with: a first body 11 in which one side of the pressure chamber 28 is formed, and which has an atmosphere introduction hole 19 having one end communicating with the pressure chamber 28 and the other end opened to the atmosphere in a side part thereof, and is provided with the fixed contacts 30 and 31; and a second body 12 in which the other side of the pressure chamber 28 is formed, and which is fixed to the first body 11. The pressure switch is equipped with a waterproof cover 13 formed into a U-shaped form, and attached to the first body 11 by surrounding the other end of the atmosphere introduction hole 19. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pressure switch that generates an electric signal by detecting a pressure difference of a fluid in, for example, an internal combustion engine of an automobile.

  As an example of the pressure switch, as shown in FIG. 4, a pressure switch 50 in which an annular waterproof cover 53 is attached to the fixed contact side body 52 of the movable contact side body 51 and the fixed contact side body 52 is known. (For example, refer to Patent Document 1).

  In such a pressure switch 50, a diaphragm 55 is assembled in a pressure chamber 54 between the movable contact side body 51 and the fixed contact side body 52, and the movable contact 56 is fixed to the diaphragm 55. The waterproof cover 53 covers the air introduction hole 57 that communicates from the pressure chamber 54 to the side portion of the fixed contact side body 52 by covering the outer peripheral portion of the fixed contact side body 52. When the negative pressure of the fluid introduced from the movable contact side body 51 exceeds a predetermined value, the diaphragm 55 is displaced against the return spring 58 in the pressure chamber 54, and accordingly, the fixed contact side body When the movable contact 56 connected to the ground is separated from the normally closed fixed contact 59 accommodated in 52, the circuit connected to the fixed contact 59 is interrupted.

JP-A-9-259721 (FIG. 1)

  However, in the pressure switch 50 disclosed in Patent Document 1, since the waterproof cover 53 has an annular shape, the attachment of the waterproof cover 53 causes the connector portion 60 included in the fixed contact side body 52 to be inserted. However, workability is not good.

  Further, since the waterproof cover 53 has an annular shape, the connector portion 60 of the fixed contact side body 52 has to be an upper insertion type from above in the figure, so that the degree of freedom in the insertion direction of the connector portion 60 is small. Therefore, it cannot be said that it is rich in versatility with other circuits.

  In addition, since the opening on the pressure chamber 54 side of the air introduction hole 57 is disposed above the movable contact 56, if a foreign object enters through the air introduction hole 57 by any chance, the foreign object is moved to the movable contact 56. Since it may fall directly onto 56, a foreign matter cover 61 for receiving foreign matter is provided on this movable contact 56. For this reason, there is a possibility that the internal components are the one in which the foreign matter cover 61 is added to the movable contact 56 and the fixed contact 59 and the number of parts is increased.

  In addition, if the atmosphere introduction hole 57 is offset and provided to the outside with respect to the internal contact by the engaging portion for assembling and fixing the annular waterproof cover from above the pressure switch, the pressure switch becomes large. .

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to improve the workability of assembling the prevention cover and improve versatility with a connected connector. An object of the present invention is to provide a pressure switch that can reduce the number of parts.

  1) A pressure switch according to the present invention is a pressure switch that includes a diaphragm assembled in a pressure chamber together with a movable contact, and causes the movable contact to contact and separate from a fixed contact in accordance with pressure applied to the pressure chamber. And a first body having the fixed contact, wherein one side of the pressure chamber is formed, one end of the pressure chamber is communicated with the pressure chamber, and the other end is open to the atmosphere at the side. And a second body formed on the other side of the pressure chamber and fixed to the first body. The pressure switch is formed in a U shape and surrounds the other end of the atmosphere introduction hole. A waterproof cover to be assembled to the first body is provided.

  According to the invention described in 1) above, the waterproof cover is U-shaped and is assembled to the first body so as to surround the other end of the air introduction hole. Assembly is possible without regard to the position of Thereby, workability can be improved and versatility with other circuits can be improved.

  2) The pressure switch according to the present invention is characterized in that, in the pressure switch according to the above 1), the waterproof cover has locking portions that are locked to the first body on both sides of the side portion. To do.

  According to the invention described in 2) above, the U-shaped waterproof cover is assembled by simply locking the locking portion on the side to the first body. Compared to, the positioning is easy, so that reliable assembly can be easily performed without making a mistake. In addition, since the locking portion is provided on the side portion of the U-shaped waterproof cover, waterproofing can be reliably achieved by the hood portion of the first body, and the locking portion is provided at a position corresponding to the air introduction hole. Since the pressure switch is not provided, the pressure switch can be offset and provided outside the size.

  3) Further, the pressure switch according to the present invention is the pressure switch according to 1) or 2) described above, wherein the waterproof cover has a protruding plate abutting against the first body, and at least a part of the protruding plate. A communication portion is formed.

  According to the invention described in 3) above, even when rainwater or the like has fallen on the pressure switch when the prevention cover is assembled to the first body so as to surround the other end of the atmosphere introduction hole, the prevention cover is protected from the atmosphere. Since the other end portion of the introduction hole is surrounded, rainwater can be prevented from entering the atmosphere introduction hole. If, for example, a large amount of rainwater has entered the rainwater, the rainwater is efficiently discharged to the outside through the communication portion formed on at least a part of the projecting plate that contacts the first body. Since the water is drained, the air introduction hole is not blocked by rainwater.

  4) Moreover, the pressure switch according to the present invention is the pressure switch according to any one of 1) to 3) described above, wherein one end of the air introduction hole is offset with respect to the movement locus of the movable contact. It is arranged.

  According to the invention described in 4) above, one end of the air introduction hole is not arranged in the movement locus of the movable contact. As a result, even if a foreign object has entered through the air introduction hole, the foreign object does not fall directly onto the movable contact. It is possible to reduce the amount and prevent a foreign matter from adhering to the movable contact, and a reliable operation can be performed.

  According to the pressure switch of the present invention, it is possible to solve the problems that workability is not good, poor versatility with other circuits, and causes an increase in the number of parts. As a result, it is possible to improve the versatility of the connector to be connected and to reduce the number of parts.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.

  FIG. 1 is an exploded perspective view illustrating the assembly relationship of components of a pressure switch according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the pressure switch shown in FIG. 1, and FIG. FIG.

  As shown in FIG. 1, a pressure switch 10 according to an embodiment of the present invention includes a first body 11, a second body 12, and a waterproof cover 13.

  The first body 11 is formed of a hard and non-conductive resin as a raw material, and a rectangular unit cap portion 15 is formed on a ring-shaped base 14 so as to protrude from the side of the unit cap portion 15. The connector part 16 is extended to the part.

  In the first body 11, a waterproof cover fixing part 18 is formed on the front end surface 17 of the unit cap part 15, and an air introduction hole 19 is formed in the central part of the waterproof cover fixing part 18. The waterproof cover fixing portion 18 is formed with a hood portion 20 projecting in a bowl shape toward the front and both sides on the side opposite to the base 14, and a pair of engaging portions 21 projecting from both sides. ing.

  The second body 12 is formed in a cylindrical shape using a resin that is the same as the first body 11 and is made of a hard and non-conductive resin. The second body 12 is combined with the base 14 of the first body 11 and then has an annular shape. By being fitted with the member 22, it is assembled integrally with the first body 11.

  The waterproof cover 13 is formed in a U-shape as a whole using a resin that is softer than the first body 11 and the second body 12 and has a little elasticity. The waterproof cover 13 has a pair of side plates 24 protruding from both sides of a curved main body 23, and a locking projection 25 formed at the tip of the side plate 24.

  The waterproof cover 13 has a pair of projecting plates 26 protruding from the inside of the side plate 24 in the main body 23. The waterproof cover 13 may be formed in a C shape instead of the U shape.

  The waterproof cover 13 is attached to the waterproof cover fixing portion 18 by locking the two locking protrusions 25 to the two engaging portions 21 of the waterproof cover fixing portion 18 from the side of the first body 11. Assembled. At this time, when it becomes necessary to remove the waterproof cover 13, for example, the tip of a tool such as a flat-blade screwdriver is hooked on the end of the side plate 24 and protrudes to the side of the waterproof cover fixing portion 18 of the first body 11. It can be easily removed by rotating the formed protrusion 27 as a fulcrum.

  As shown in FIGS. 2 and 3, the first body 11 has a first body side pressure chamber 29, which is one side of the pressure chamber 28, formed on the end surface on the second body 12 side. Two normally closed fixed contacts 30 and 31 protrude into the side pressure chamber 29. The fixed contacts 30 and 31 are formed at one end portions of the two terminals 32 and 33 accommodated in the first body 12, and the other end portions of the terminals 32 and 33 are disposed in the connector portion 16. .

  Further, the first body 11 has an end portion of a vertical hole which is the other end portion of the air introduction hole 19 opened at the air outlet port 34 at the side of the first body side pressure chamber 29. An end portion of the horizontal hole that is one end portion of 19 is opened in the waterproof cover fixing portion 18 by an air introduction port 35 protruding in a cylindrical shape.

  In the waterproof cover 13, communication portions 36 and 37, which are I-shaped cut surfaces, are formed at an upper end portion and a lower end portion, which are at least a part of each protruding plate 26. The upper communication part 36 forms a gap with the hood part 20, and the lower communication part 37 forms a gap with the base 14.

  The waterproof cover 13 is assembled to the waterproof cover fixing portion 18, whereby the main body 23 is disposed to face the air introduction port 35, and the protruding plate 26 is brought into contact with the end surface 17 of the waterproof cover fixing portion 18. As a result, the air introduction port 35 of the air introduction hole 19 is surrounded by the base 14 at the lower side and the hood part 20 at the upper side, the front surface is the main body 23 of the waterproof cover 13, and both sides are the protruding plates 26 of the waterproof cover 13. By being surrounded by each, the atmospheric air is released so that rainwater does not directly enter the air introduction hole 19.

  The second body 12 has a second body-side pressure chamber 38 that is the other side of the pressure chamber 28 formed on the end surface on the first body 11 side, and is in communication with the second body-side pressure chamber 38. 2 A pressure introduction hole 39 opened at the end of the body 12 is formed. In the pressure introduction hole 39, a return spring 40, a cylindrical member 41, and two hollow nut members 42 and 43 are incorporated.

  A movable contact 45 is assembled to the upper end of the return spring 40 with a diaphragm 44 interposed therebetween. The diaphragm 44 is arranged by dividing the pressure chamber 28 into two parts by sandwiching the outer edge part between the end parts of the first body 11 and the second body 12, and the movable contact 45 is assembled to the inner edge part. ing. The movable contact 45 has two hollow nut members 42 and 43 screwed into predetermined positions of the cylindrical member 41, so that the fixed contacts 30 and 31 are connected via the diaphragm 44 with the elastic repulsion force accumulated in the return spring 40. Each contacted.

  The movable contact 45 comes into contact with the fixed contacts 30 and 31 when the fluid pressure applied to the pressure introduction hole 39 through the hollow nut members 42 and 43 is smaller than the elastic repulsion force accumulated in the return spring 40. Then, the fixed contacts 30 and 31 are made conductive. On the contrary, when the fluid pressure becomes larger than the elastic repulsion force accumulated in the return spring 40, the fixed contacts 30, 31 are blocked by moving away from the fixed contacts 30, 31 against the return spring 40.

  At this time, the moving contact 45 is within a range A shown in FIG. On the other hand, the atmosphere outlet 34 serving as the other end of the atmosphere introduction hole 19 is opened at a position offset from the range A of the movement locus, and thus is not disposed so as to overlap the range A of the movement locus. .

  When detecting a negative pressure, such a pressure switch 10 is fixed to the engine by communicating a pressure introduction hole 39 in an intake passage (not shown) of the engine, and is electrically connected to an engine control circuit. A connector accommodating the terminal is connected to the connector portion 16.

  As the engine is started, negative pressure is generated in the intake passage. Therefore, when the negative pressure generated in the intake flow path is smaller than the elastic repulsion force accumulated in the return spring 40, the movable contact 45 comes into contact with the fixed contacts 30 and 31, respectively. 31 is turned on to bring the engine control circuit to a low level. On the other hand, when the fluid pressure becomes larger than the elastic repulsive force accumulated in the return spring 40, the movable contact 45 moves away from the fixed contacts 30, 31 against the return spring 40, thereby causing the fixed contacts 30, 31. And the engine control circuit is caused to recognize that the negative pressure has increased by setting the engine control circuit to a floating level.

  At this time, air is introduced into the first body-side pressure chamber 38 from the air introduction hole 19 surrounded by the waterproof cover 13. When rainwater is applied to the pressure switch 10, the rainwater does not directly enter the atmosphere introduction hole 19 because the atmosphere introduction port 35 of the atmosphere introduction hole 19 is surrounded by the waterproof cover 13. If rainwater applied to the pressure switch 10 intrudes into the waterproof cover 13, the air introduction port 35 protrudes in a cylindrical shape and the base 14 side of the communication portions 36 and 37 of the protruding plate 26. By draining rainwater from the communication portion 37, the rainwater does not directly enter the atmosphere introduction hole 19.

  As described above, according to the pressure switch 10, the waterproof cover 13 has a U shape and is assembled to the first body 11 so as to surround the other end of the air introduction hole 19. Assembling can be carried out without regard to the position of the connector portion 16 formed in this. Thereby, workability can be improved and versatility with other circuits can be improved.

  In addition, according to the pressure switch 10, the U-shaped waterproof cover 13 can be assembled simply by locking the locking protrusion 25 on the side to the engaging portion 21 of the first body 11. Compared with the conventional shape having a shape, positioning is easy, so that reliable assembly can be easily performed without causing a mistake.

  Further, since the locking projections 25 are provided on both sides of the U-shaped waterproof cover 13, the hood portion 20 of the first body 11 can surely be waterproofed, and the position corresponding to the air introduction hole 19. Therefore, the air introduction hole 19 can be offset to the outside without increasing the size of the pressure switch 10.

  Further, according to the pressure switch 10, even when rainwater or the like falls on the pressure switch 10 during use, the prevention cover 13 surrounds the other end of the air introduction hole 19 and is assembled to the first body 11. Since 13 surrounds the air inlet 35 at the other end of the air inlet 19, rainwater can be prevented from entering the air inlet 19. In the event that, for example, a large amount of rainwater has entered the rainwater, the rainwater is efficiently drained to the outside through the communicating portion 37 of the protruding plate 26 that contacts the first body 11. In addition, the air introduction hole 19 is not blocked by rainwater.

  Further, according to the pressure switch 10, the atmosphere outlet 34 at one end of the atmosphere introduction hole 19 is not disposed in the movement locus of the movable contact 45. As a result, even if foreign matter has entered through the air introduction hole 19, the foreign matter does not fall directly onto the movable contact 45, so there is no need to provide a foreign matter cover like the conventional one. A reduction in the number of points can be achieved, and a foreign substance can be prevented from adhering to the movable contact 45 and a reliable operation can be performed.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

It is a disassembled perspective view explaining the assembly | attachment relationship of each component of the pressure switch which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view of the pressure switch shown in FIG. FIG. 3 is a horizontal sectional view around a waterproof cover in FIG. 2. It is sectional drawing of the conventional pressure switch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pressure switch 11 1st body 12 2nd body 13 Waterproof cover 19 Atmospheric introduction hole 25 Locking protrusion (locking part)
26 Protruding plate 28 Pressure chamber 30, 31 Fixed contact 36, 37 Communication portion 44 Diaphragm 45 Movable contact

Claims (4)

A pressure switch comprising a diaphragm assembled in a pressure chamber together with a movable contact, wherein the movable contact is brought into and out of contact with a fixed contact in accordance with pressure applied to the pressure chamber,
A first body provided with the fixed contact, wherein one side of the pressure chamber is formed, and has an air introduction hole having one end communicating with the pressure chamber and the other end opened to the atmosphere at the side; ,
A pressure switch having a second body formed on the other side of the pressure chamber and fixed to the first body;
A pressure switch comprising a waterproof cover that is formed in a U-shape and is attached to the first body so as to surround the other end of the air introduction hole.   2. The pressure switch according to claim 1, wherein the waterproof cover has locking portions that are locked to the first body on both sides of the side portion. 3.   3. The pressure switch according to claim 1, wherein the waterproof cover includes a projecting plate that contacts the first body, and a communication portion is formed on at least a part of the projecting plate. 4.   The pressure switch according to any one of claims 1 to 3, wherein one end portion of the air introduction hole is arranged to be offset with respect to a movement locus of the movable contact.

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