JP2005209438A - Pressure switch and operation point adjusting method of the pressure switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure switch not generating chattering even when used for a low pressure detection, excellent in an oil-resistant property, having good durability against temperature change, with a contact part never to be put in oil, not requiring large electric capacity, capable of adjusting an operation point (operation pressure) constant. <P>SOLUTION: The pressure switch comprises a conductive joint part 4; an insulating connector part 6 jointed to the joint part 4; a fixed terminal 12 arranged at the connector part 6; a diaphragm 10 made of metal arranged in the joint part 4 operating in compliance with pressure; and a conductive movable member 16 with one end side connected to the fixed terminal 12, arranged at an upper part of the diaphragm 10. The diaphragm 10 made of metal is arranged so as to contact the other end side of the movable member 16 when the pressure added thereon exceeds a prescribed pressure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pressure switch suitable for detecting, for example, the hydraulic pressure of an automatic transmission of an automobile.

  Conventionally, for example, in an automobile, a pressure switch for detecting a lubricating oil pressure is provided in order to detect whether or not the lubricating oil pressure is appropriate or to detect an operating state of the engine. A pressure switch is also used to detect engine intake pressure, exhaust pressure, crank chamber pressure, various actuator operating pressures, and the like.

  These pressure switches have, for example, the structure schematically shown in FIG.

  That is, the conventional pressure switch 70 includes a joint portion 62 made of a conductive material having a fixing portion 61 screwed to a vehicle device 60 such as a transmission, and the upper portion of the joint portion 62 by caulking. And an insulative connector portion 63 fixed in 62.

  A diaphragm 64 is interposed between the joint portion 62 and the connector portion 63, and a movable contact 65 is attached to a substantially central portion of the diaphragm 64.

  Further, a metal member 67 is disposed inside the connector portion 63, and a coil spring 66 is interposed between the metal member 67 and the movable contact 65 on the diaphragm 64 in a compressed state. As a result, the diaphragm 64 and the movable contact 65 are biased downward.

  Accordingly, when the hydraulic pressure in the vehicle device 60 such as a transmission to which the pressure switch 70 is attached by the fixed portion 61 is low, that is, when the pressure in the pressure chamber 69 is low, the diaphragm 64 is urged by the urging force of the compression coil spring 66. The movable contact 65 is lowered, and the fixed contact 68 and the movable contact 65 are connected.

  Therefore, in this state, a conductive path from the metal member 67 to the coil spring 66, the movable contact 65, the fixed contact 68, and the joint portion 62 is formed, and the pressure switch 70 is turned on. .

  On the other hand, as the hydraulic pressure in the pressure chamber 69 increases from this state, the diaphragm 64 is pressed upward against the coil spring 66 and moves upward, and the gap between the movable contact 65 and the fixed contact 68 is increased. The pressure switch 70 is turned off by being separated.

  Note that the space immediately below the diaphragm 64 and the pressure chamber 69 below the space 64 communicate with each other through a passage (not shown) so that the movement of the diaphragm 64 is not hindered.

  When the fixed contact 68 and the movable contact 65 are in contact with each other, a conductive path from the metal member 67 to the coil spring 66, the movable contact 65, the fixed contact 68, and the joint portion 62 is formed. The device 60 is body-grounded.

  By the way, in such a conventional pressure switch 70, a rubber diaphragm is usually employed as the diaphragm 64 that fluctuates due to the pressure fluid. A coil spring 66 is interposed in a compressed state between the metal member 67 and the movable contact 65 on the diaphragm 64.

  However, when such a rubber diaphragm 64 is used for a pressure switch for detecting a low pressure or a low pressure, the rubber diaphragm 64 has almost no differential. That is, the diaphragm 64 may be displaced by a slight pressure pulsation, chattering may occur, and the pressure switch may be frequently turned on and off, so that accurate pressure switch operation may not be guaranteed. It was.

  Further, in the conventional pressure switch 70, for example, when used as a pressure switch for detecting the lubricating oil pressure, the rubber diaphragm 64 is disposed in the oil in the pressure chamber 69, that is, the rubber switch. Since the diaphragm 64 is in contact with the oil, the rubber may deteriorate depending on the type of oil or due to the temperature change of the oil, and the function as a pressure switch may be hindered.

  Furthermore, in the conventional pressure switch 70, since the contact part comprised from the movable contact 65 and the fixed contact 68 is arrange | positioned in the state which contacted the oil in the pressure chamber 69, a big electrical capacity is required for conduction | electrical_connection, There was a problem that it could not be handled as a weak use.

  Further, since the conventional pressure switch 70 is not provided with any means for adjusting the operating point (operating pressure), the operating point (operating pressure) is not stable if the operating characteristics of the manufactured diaphragm 64 vary. There was a problem.

  In view of such a current situation, the present invention has no chattering even when used for low-pressure detection, and has excellent oil resistance, durability against temperature changes, and contact parts in oil. A pressure switch that is not disposed and does not require a large electric capacity and that can adjust the operating point (operating pressure) to a constant value when a different diaphragm is used, and an operating point adjusting method for the pressure switch The purpose is to provide.

The present invention has been invented in order to achieve the problems and objects in the prior art as described above.
Conductive joints,
An insulating connector part joined to the joint part;
A fixed terminal disposed in the connector portion;
A metal diaphragm disposed in the joint and operating in response to pressure;
A conductive movable member disposed above the metal diaphragm and having one end connected to a fixed terminal;
When the pressure applied to the metal diaphragm is equal to or higher than a predetermined pressure, the metal diaphragm comes into contact with the other end of the movable member to reach the movable member, the metal diaphragm, and the joint portion from the fixed terminal. The present invention is characterized in that a conductive path is formed.

  Since the metal diaphragm is used in this way, the metal diaphragm has a differential, so that the diaphragm does not displace due to a slight pressure change, that is, a slight pressure pulsation, and chattering occurs. In addition, since the pressure switch is not frequently turned on and off, accurate pressure switch operation is guaranteed.

  Therefore, even when applied to a pressure switch for detecting a low pressure or a low pressure, an accurate pressure switch operation can be obtained.

  In addition, the metal diaphragm has excellent oil resistance, durability against temperature changes, and a pressure switch with excellent versatility can be obtained.

  In addition, a contact portion is formed between the metal diaphragm and the conductive movable member disposed above the metal diaphragm, and this contact portion does not contact the pressure load side, that is, oil. Since the contact portion is not disposed in the oil, a large electric capacity is not necessary for conduction, and it is possible to prevent poor contact and facilitate electrical conduction. It can also be used for weak use.

The pressure switch of the present invention is
The movable member is
An elastic arm having one end fixed to the fixed terminal;
An operating shaft is provided that is fixed to the elastic arm and is in contact with the metal diaphragm when a pressure applied to the metal diaphragm becomes equal to or higher than a predetermined pressure.

  With this configuration, when the pressure applied to the metal diaphragm exceeds a predetermined pressure, the metal diaphragm moves upward against the urging force of the elastic arm downward. The operating shaft is pressed upward by coming into contact with the shaft, but the operating shaft is pressed downward by the metal diaphragm by the restoring force due to the downward biasing force of the elastic arm. In addition, in this state, the contact pressure increases because the operating shaft and the metal diaphragm are close to point contact.

  Therefore, a conductive path is formed from the fixed terminal to the movable member, the operating shaft of the movable member, the metal diaphragm, and the joint portion, and it is possible to ensure electrical conductivity and stabilize the contact pressure for body grounding.

Further, the pressure switch of the present invention includes a position adjusting means for adjusting a distance between a tip of the operating shaft and a substantially central portion of the metal diaphragm,
The position adjusting means includes an adjusting pin that is movably mounted in the joint portion from the connector portion.

  By adopting such a configuration, when the pressure applied to the metal diaphragm reaches a predetermined pressure, the pushing length of the adjustment pin is adjusted so that the tip of the operating shaft comes into contact with the metal diaphragm. By adjusting the distance between the tip of the operating shaft and the metal diaphragm so that the tip of the operating shaft and the metal diaphragm come into contact with each other when the pressure applied to the metal diaphragm reaches a predetermined pressure. Therefore, it is possible to always operate at the same predetermined pressure, and to adjust the variation of the operating point (operating pressure).

  Moreover, when the pressure applied to the metal diaphragm becomes equal to or higher than a predetermined pressure, the pressure switch is always turned on at the upper limit position. In this state, the force by which the operating shaft is pressed downward by the metal diaphragm is maintained at a predetermined pressure by the force pressing the operating shaft of the metal diaphragm upward and the restoring force by the downward biasing force of the elastic arm. As a result, a stable contact pressure can be obtained.

The pressure switch according to the present invention is characterized in that an adjustment pin guide member for fixing the adjustment pin is formed at one end of the fixed terminal on the joint part side.

  By comprising in this way, the connector part which consists of resin, such as PPS, and a metal adjustment pin by thermal expansion and contraction by the change of use temperature, for example, a temperature change of -40 degreeC-+150 degreeC, for example Even if there is a gap between them, so-called rattling occurs, the adjustment pin is fixed by the adjustment pin guide member, for example, by press-fitting. Since the position does not shift, the operating point (operating pressure) is not shifted.

  In addition, since the adjustment pin guide member is made of metal, the adjustment pin and the adjustment pin guide member are fitted with each other, so that the thermal expansion and contraction rate are almost the same even if the temperature changes. So, between the adjustment pin and the adjustment pin guide member. Since there is no gap and so-called rattling does not occur, the holding load of the adjustment pin does not decrease and the position of the operating shaft does not slip, so that the operating point (operating pressure) may shift. Absent.

  Also, if the adjustment pin and the adjustment pin guide member are metal-to-metal fittings, even if there is a change in temperature, the holding force will return to the same holding force when it returns to room temperature, so the holding load on the adjustment pin will decrease. Since the position of the operating shaft is not shifted, the operating point (operating pressure) is not shifted.

In the pressure switch of the present invention, the adjustment pin guide member is
An adjustment pin guide member body bent into a substantially L shape from one end of the fixed terminal on the joint part side;
The adjustment pin guide member main body is formed of an adjustment pin guide hole for fixing the adjustment pin.

  With this configuration, the adjustment pin and the adjustment pin guide hole are arranged coaxially, the adjustment pin is fitted into the adjustment pin guide hole, and the adjustment pin is fixed by, for example, press-fitting. The structure is simple and the assembly work is facilitated.

  The pressure switch according to the present invention is characterized in that the pressure in the joint portion is maintained at substantially the same pressure as the outward pressure by forming the adjustment pin in a hollow shape. To do.

  With this configuration, the pressure in the joint portion where the movable member is arranged can always be maintained at the same pressure as the external pressure via the hollow communication portion of the adjustment pin. It is possible to prevent the internal pressure from increasing.

  Therefore, the internal pressure in the joint due to the temperature rise does not act on the back side of the metal diaphragm, i.e., a large downward pressure that prevents the deformation of the metal diaphragm. There is no end.

  The pressure switch according to the present invention is characterized in that the elastic arm is formed in a substantially J-shaped cross section.

  By comprising in this way, an elastic force can be easily provided to an elastic arm, and the contact pressure between an operating shaft and a metal diaphragm can be stabilized.

Further, the operating point adjustment method in the pressure switch of the present invention is an adjustment method of the operating point in the pressure switch,
While applying a predetermined pressure to the metal diaphragm and moving the adjustment pin of the position adjusting means downward,
Move the operating shaft downward, the operating shaft abuts the metal diaphragm, and the position of the operating shaft at the time when conduction from the fixed terminal to the movable member, the metal diaphragm, and the joint is secured is activated. It is characterized by adjusting so that it may become the position of the front-end | tip part of an axis | shaft.

  In this way, when the pressure applied to the metal diaphragm reaches a predetermined pressure, the pushing length of the adjustment pin is adjusted so that the tip of the operating shaft comes into contact with the metal diaphragm. Can easily adjust the distance between the tip of the operating shaft and the metal diaphragm, so that even when using a metal diaphragm with different operating characteristics, it can always operate at the same predetermined pressure. The variation of the operating point (operating pressure) can be adjusted.

  According to the present invention, since the metal diaphragm is used, the diaphragm does not displace with respect to slight pressure change, that is, slight pressure pulsation, chattering does not occur, and the pressure switch Since ON / OFF does not occur frequently, accurate pressure switch operation is guaranteed even when applied to a pressure switch for detecting a low pressure or a low pressure.

  Moreover, the metal diaphragm is excellent in oil resistance, has excellent durability against temperature changes, and can provide a pressure switch excellent in versatility.

  Furthermore, a contact portion is formed between the metal diaphragm and the conductive movable member disposed on the upper portion of the metal diaphragm, and this contact portion does not contact the pressure load side, that is, oil. Since the contact portion is not disposed in the oil, a large electric capacity is not required for conduction, and it can be used for weak use.

  Hereinafter, embodiments (examples) of the present invention will be described in more detail with reference to the drawings.

  FIG. 1 is a schematic longitudinal sectional view showing an embodiment of the pressure switch of the present invention, FIG. 2 is a partially enlarged sectional view showing a positional relationship of operating points (operating pressures) of the pressure switch of FIG. 1, and FIG. FIG. 4 is a partial enlarged cross-sectional view showing the positional relationship of the ON state of the switch of the pressure switch of FIG. 1, and FIG.

  As shown in FIG. 1, in the pressure switch 2 of the present invention, a casing is constituted by a conductive joint portion 4 and an insulating connector portion 6, and a pressure chamber 8 is defined in the casing. A non-inverted type metal diaphragm 10 having characteristics as shown by a solid line in FIG. 4 is disposed between the joint portion 4 and the connector portion 6.

  In addition, a flat fixed terminal 12 having a substantially L-shaped cross section is inserted into the connection-side recess 6 a of the connector portion 6, and its tip end portion 12 a has a contact operation chamber defined in the connector portion 6. 14.

  A conductive movable member 16 is disposed above the metal diaphragm 10. That is, the conductive movable member 16 faces the metal diaphragm 10 above the metal diaphragm 10 and the elastic arm 18 having a substantially J-shaped cross section whose one end is fixed to the distal end portion 12 a of the fixed terminal 12. And an operating shaft 20 fixed to a substantially central portion of the elastic arm 18.

  The movable member 16 composed of the elastic arm 18 and the operating shaft 20 is made of, for example, stainless steel. Moreover, the front-end | tip part 12a of the fixed terminal 12 and the elastic arm 18 are connected by the crimping process 15, for example in this Example. However, the connection between the distal end portion 12a of the fixed terminal 12 and the elastic arm 18 can employ known fixing means such as welding and brazing, and is not particularly limited.

  In this case, the elastic arm 18 is urged upward by the elastic force so as to bend toward the adjustment pin 24 in the state of FIG. That is, when the adjustment pin 24 is separated (removed) from the state of FIG. 1, the elastic arm 18 is disposed in a state where the end of the separated elastic arm 18 on the straight side is curved upward. ing.

  Further, in this embodiment, when the metal diaphragm 10 comes into contact with the operating shaft 20 fixed to the substantially central portion of the elastic arm 18, the elastic arm 18 of the movable member 16, from the fixed terminal 12, Since a conductive path extending to the operating shaft 20, the metal diaphragm 10, and the joint portion 4 is formed and electrical conductivity is ensured, it has a function as a body ground.

  Further, in this pressure switch 2, the contact pressure is stabilized by the reaction force from the elastic arm 18 generated when the metal diaphragm 10 abuts against the operating shaft 20.

  That is, when the metal diaphragm 10 is pressed upward from the position of the solid line in FIG. 1 by the pressure in the pressure chamber 8 and comes into contact with the tip of the operating shaft 20 as indicated by the broken line, the elastic arm 18 is With the tip of the adjustment pin 24 as a fulcrum, a force in the direction away from the metal diaphragm 10 (upward) is received against the downward biasing force of the elastic arm 18.

  At this time, in the elastic arm 18 itself, a restoring force (downward restoring force) is generated to return to the original position on the metal diaphragm 10 side while being supported by the tip of the adjustment pin 24. As a result, the contact pressure between the metal diaphragm 10 and the operating shaft 20 is increased. Moreover, in this state, the contact pressure increases because the operating shaft 20 and the metal diaphragm 10 are in a state close to point contact.

  Accordingly, a conductive path is formed from the fixed terminal 12 to the movable member 16 (the elastic arm 18 and the operating shaft 20), the metal diaphragm 10, and the joint portion 4, and it is possible to ensure electrical continuity and contact pressure for grounding the body. Can be stabilized.

  Moreover, as shown in FIG. 2, the opening 22a is formed in the center part of the stopper member 22, and the peripheral part of the opening 22a is formed in the taper shape. As a result, a tapered guide slope 26 whose thickness decreases toward the opening 22a is formed.

  1 and 2, when the metal diaphragm 10 is deformed upward, as shown in FIG. 3, the metal diaphragm 10 is deformed along the guide slope 26, and the lower end of the opening 22a of the stopper member 22 is deformed. The position U is used as the final end of the moving range, and is deformed to this position.

  A pin insertion hole 6b is formed in the connection-side recess 6a of the connector portion 6, and an adjustment pin 24 is inserted into the pin insertion hole 6b so that the position can be adjusted. As will be described later, the adjustment pin 24 is pushed against the urging force to be lifted above the elastic arm 18, so that the adjustment pin 24 and the elastic arm 18 are always in contact with each other.

Further, the adjustment pin 24 is formed in a hollow shape, and the hollow hole 24a communicates with the contact operation chamber 14 in the connector portion 6, so that the pressure in the contact operation chamber 14 is increased due to a temperature increase or the like. Also, the atmospheric pressure is maintained through the hollow hole 24a. Therefore, a large downward pressure that prevents the deformation of the metal diaphragm 10 does not act on the back side of the metal diaphragm 10, that is, on the upper surface of the metal diaphragm 10.

  In this case, although not shown, the tip of the adjustment pin 24 is not shown at the tip of the adjustment pin 24 so that the communication by the hollow hole 24a is ensured even when the tip of the adjustment pin 24 is in contact with the elastic arm 18 of the movable member 16. A corrugated split pin-shaped slit is formed, and communication is ensured through this slit.

  Such a pressure switch 2 is attached to a vehicle device 60 such as a transmission, for example, so that a low pressure is detected, for example.

  Further, in the pressure switch 2 of the present invention, the adjusting pin 24 constitutes a position adjusting means for adjusting the position t of the operating shaft 20 at the operating point (operating pressure) P1. If the length of the adjustment pin 24 to be pushed in is adjusted by the position adjusting means, as will be described later, as shown in FIG. 2, the position t of the end of the operating shaft 20, that is, a metal made at a predetermined operating pressure P1 is used. The position of the operating shaft 20 at the operating point (operating pressure) P1 at which the diaphragm 10 contacts the operating shaft 20 can be determined. That is, the position t of the operating shaft 20 at the operating point (operating pressure) P1 can be adjusted.

  2 and 3, when the metal diaphragm 10 is deformed upward, the metal diaphragm 10 is deformed along the guide slope 26, and the position U of the lower end of the opening 22a of the stopper member 22 is set. As the final end of the moving area, the moving area is defined by the stopper member 22 so as to be deformed to this position. When the position U becomes equal to or higher than a predetermined operating pressure, the pressure switch 2 is turned on, and this position is defined by the stopper member 22.

  As shown in FIG. 2, when the tip of the operating shaft 20 is set at the operating point position t at the operating point (operating pressure) P1 by a method described later, as shown in FIG. Is filled with an adhesive 27, and the adjustment pin 24 is fixed to be immovable. Thereby, the position of the operating shaft 20 is fixed. In FIG. 1, reference numerals 28 and 29 denote O-rings.

  Hereinafter, how to determine the position of the tip of the operating shaft 20 to be the operating point position t at the operating point (operating pressure) P1 will be described.

  First, the O-ring 29 is mounted in the joint portion 4, the metal diaphragm 10 is placed thereon, and the stopper member 22 is placed thereon.

  Then, on the stopper member 22, the fixed terminal 12, the movable member 16 including the elastic arm 18 and the operating shaft 20, and the connector portion 6 to which the O-ring 28 is attached are fitted in advance. In this state, as shown in FIG. 1, the upper end portion 4a of the joint portion 4 is crimped inward to join the joint portion 4 and the connector portion 6 to form a casing.

  As a result, the pressure chamber 8 is hermetically sealed, and as shown in FIG. 4, a predetermined operating pressure P1 is applied to the pressure chamber 8 and this predetermined pressure P1 is applied to the metal diaphragm 10.

In this state, the operating shaft 20 is moved downward by moving (pushing) the adjustment pin 24 downward against the urging force to lift the elastic arm 18 upward. As a result, the tip of the operating shaft 20 abuts on the metal diaphragm 10, and conduction from the fixed terminal 12 to the movable member 16 (elastic arm 18, operating shaft 20), the metal diaphragm 10, and the joint portion 4 is ensured. Further, the position of the tip of the operating shaft 20 at the time point when the conduction is confirmed is set as the position of the operating point position t at the operating point (operating pressure) P1.

  When the tip of the operating shaft 20 is set to the operating point position t at the operating point (operating pressure) P1, as shown in FIG. 1, the adhesive 27 is filled on the head side of the adjusting pin 24 and the adjusting pin 24 is moved. Fix impossible. Thereby, the position of the operating shaft 20 is fixed.

  By adjusting the pushing amount of the adjusting pin 24 in this way and moving the tip of the working shaft 20, the tip of the working shaft 20 is disposed at the working point position t at the working point (working pressure) P1. The desired pressure P1 can be set as the operating pressure.

  As a result, even when the metal diaphragm 10 having different operating characteristics is used, it is possible to always operate at the same predetermined operating pressure P1 only by adjusting the pushing amount of the adjusting pin 24, and the operating point ( The variation of the operating pressure (P1) can be adjusted.

  Below, the effect | action of the pressure switch 2 by which the operating point (operating pressure) was adjusted as mentioned above is demonstrated.

  First, when the hydraulic pressure in the vehicle device 60 to which the pressure switch 2 is attached is equal to or lower than a predetermined pressure, the metal diaphragm 10 maintains the solid line state in FIG. That is, the metal diaphragm 10 is in a non-contact state with the tip of the operating shaft 20.

  When the hydraulic pressure in the vehicle device 60 rises from this state and the hydraulic pressure in the pressure chamber 8 increases, the central portion of the metal diaphragm 10 gradually rises, and as shown in FIGS. It abuts against the operating shaft 20 at the position t (position X). The pressure P1 at this time is the operating point (operating pressure) of the pressure switch.

  At this operating point (operating pressure) P <b> 1, the metal diaphragm 10 is kept lightly pressed against the operating shaft 20 by the hydraulic pressure of the pressure chamber 8. The metal diaphragm 10 is not carelessly deformed when pressure is applied from the pressure chamber 8 side, so that chattering is prevented from occurring in this state.

  Further, when the pressure in the pressure chamber 8 rises above the operating point (operating pressure) P1, the metallic diaphragm 10 further bulges and deforms, and as shown in FIG. 3, the metallic diaphragm 10 is deformed along the guide slope 26. When the deformation of the diaphragm 10 reaches the final region, the position of the central portion of the diaphragm 10 becomes the upper position U. Thereby, the state which the metal diaphragm 10 and the action | operation shaft 20 contact | abutted completely, ie, the state of ON, is maintained.

  By the way, in the state of being turned on in this way, the elastic arm 18 has the tip of the adjustment pin 24 abutted by the upward deformation from the position (position X) of the operating point position t of the metal diaphragm 10. With the contacted portion as a fulcrum, the central side is pressed upward against the downward biasing force of the elastic arm 18.

  As a result, the elastic arm 18 is subjected to a downward restoring force to return to the elastic arm 18 itself, with the portion where the tip of the adjustment pin 24 is in contact as a fulcrum, and the operating shaft 20 is made of metal. The diaphragm 10 is pressed downward.

On the other hand, the pressure in the pressure chamber 8 is always applied to the metal diaphragm 10 from the opposite direction, that is, upward, with respect to the downward restoring force of the elastic arm 18. The operating shaft 20 is pressed upward against the downward urging force.

  Therefore, when the operating shaft 20 and the metal diaphragm 10 are in the ON state, the pressure that antagonizes in the vertical direction acts between the operating shaft 20 and the metal diaphragm 10 in this way. Thereby, the contact pressure between the metal diaphragm 10 and the operating shaft 20 is stronger than the contact pressure at the operating point position t (position X) where the metal diaphragm 10 and the operating shaft 20 are in contact with each other. It has become.

  In this complete ON state, a conductive path is formed from the fixed terminal 12 to the movable member 16 (elastic arm 18, operating shaft 20), the metal diaphragm 10, and the joint portion 4. The body is grounded to the vehicle device 60 side through the joint portion 4.

  On the other hand, as shown in FIG. 4, as the pressure in the pressure chamber 8 decreases from the ON state, the central portion of the metal diaphragm 10 is in the ON state as shown in FIG. 3. As shown in FIG. 2, when the pressure drops from the position U to the operating point (operating pressure) P1, the pressure gradually decreases to the position (position X) of the operating point position t.

  In this case, since the downward restoring force that the elastic arm 18 tries to return to the original state is acting on the operating shaft 20, the operating shaft 20 does not move when the metal diaphragm 10 is slightly lowered. Never leave.

  However, as shown in FIG. 4, when the pressure in the pressure chamber 8 further decreases and falls below the operating point (operating pressure) P <b> 1, the central portion of the metal diaphragm 10 is positioned at the operating point position t ( Since the operating shaft 20 does not descend downward when it is lowered from the position X) and exceeds the restoring region of the elastic arm 18, the operating shaft 20 is separated from the metal diaphragm 10 and performs a reliable OFF action. It is like that.

  In the pressure switch 2 of this embodiment, the above operation is repeated as the pressure in the pressure chamber 8 increases or decreases.

  Thus, in the pressure switch 2 according to this embodiment, since a restoring force acts on the elastic arm 18, a relatively large contact pressure is applied between the metal diaphragm 10 and the operating shaft 20. It is possible to prevent poor contact with the diaphragm 10 made of electricity, and electrical conduction is easy.

  Further, in the pressure switch 2 according to this embodiment, since the metal diaphragm 10 has a differential, the metal diaphragm 10 is not displaced by a slight pressure change, that is, a slight pressure pulsation, Since chattering does not occur and the pressure switch 2 does not frequently turn on and off, accurate pressure switch operation is assured.

  Therefore, even when applied to a pressure switch for detecting a low pressure or a low pressure, an accurate pressure switch operation can be obtained.

  Moreover, the metal diaphragm 10 is excellent in oil resistance, has excellent durability against temperature changes, and can provide the pressure switch 2 excellent in versatility.

Further, a contact portion is configured between the metal diaphragm 10 and the conductive movable member 16 (the elastic arm 18 and the operating shaft 20) disposed above the metal diaphragm 10, and this contact portion. Is placed on the pressure load side, that is, the side that does not come into contact with oil, so the contact part is not placed in the oil, no large electric capacity is required for conduction, and poor contact is prevented It is easy to achieve electrical continuity and can be used for weakness.

  In this embodiment, the metal diaphragm 10 employs a metal diaphragm 10 that does not reverse as shown in FIG. 4, but instead, as shown by the dotted line in FIG. An inversion type metal diaphragm can also be employed.

  However, when a metal diaphragm that is inverted is employed, it is difficult to adjust the operating point. That is, FIG. 4 shows the difference in operating characteristics of the pressure switch between when the non-inverted type metal diaphragm 10 is used (solid line) and when the inverted type metal diaphragm is used (dotted line). The horizontal axis indicates pressure, and the vertical axis indicates displacement.

In FIG. 4, the pressure P <b> 1 indicates the operating point (operating pressure), and is the pressure at the operating point position t, that is, the position X.

  In this case, as shown by the solid line in FIG. 4, in the non-inverted type metal diaphragm 10, the displacement increases gradually due to the pressure increase, but reverses as shown by the dotted line in FIG. 4. In the case of a type of metal diaphragm, it increases with a sharp curve.

  Therefore, if the operating point position t, that is, the position X is to be determined at the operating point (operating pressure) P1, it is difficult to adjust the reversing type diaphragm because the amount of displacement is in the middle of abrupt change. . On the other hand, if the metallic diaphragm 10 is of a type that does not invert, the adjustment is easy because it is in the range of gently rising. For these reasons, a metal diaphragm 10 that is inverted may be used, but it is more preferable to use a metal diaphragm 10 that is not inverted.

  FIG. 5 is a schematic longitudinal sectional view showing another embodiment of the pressure switch of the present invention.

  The pressure switch 2 of this embodiment has basically the same configuration as the pressure switch 2 shown in FIG. 1, and the same reference numerals are assigned to the same components.

  In the pressure switch 2 of the embodiment of FIG. 1, the adjustment pin 24 is inserted into the pin insertion hole 6 b in the connection-side recess 6 a of the connector portion 6 and is lowered and adjusted in position in a state close to press-fitting. An adhesive 27 is filled on the head side of the adjustment pin 24 to fix the adjustment pin 24 so as not to move.

  Therefore, in the pressure switch 2 of the embodiment of FIG. 1, there is no gap between the connector portion 6 and the adjustment pin 24, so that the adjustment pin 24 does not have a so-called rattling.

  However, due to a change in operating temperature, for example, a temperature change of −40 ° C. to + 150 ° C., due to thermal expansion and contraction, for example, the pin insertion hole 6b of the connector portion 6 made of resin such as PPS and the metal adjustment pin 24 A gap is generated between the two and so-called rattling occurs. For this reason, the pressing load of the adjustment pin 24 is reduced, the position of the operating shaft 20 is shifted, and the operating point (operating pressure) is shifted, which may prevent accurate pressure switch operation. There is.

In addition, the connector portion 6 made of resin may be deteriorated under a high temperature environment, and this also causes a gap between the pin insertion hole 6b of the connector portion 6 and the metal adjustment pin 24. That is, so-called rattling occurs.

  For this reason, in the pressure switch 2 of this embodiment, as shown in FIG. 5, a metal that fixes the adjustment pin 24 to the inside of the joint portion 4 of the fixed terminal 12, that is, to the one end 12 a on the contact operation chamber 14 side. The adjustment pin guide member 30 is formed.

  That is, the adjustment pin guide member 30 is an adjustment pin guide member main body 32 that is bent in a substantially L shape from the one end of the fixed terminal 12 on the joint portion 4 side, that is, the one end 12a on the contact operation chamber 14 side toward the adjustment pin 24. Is provided. An adjustment pin guide hole 34 for fixing the adjustment pin 24 is formed in the adjustment pin guide member main body 32.

  The adjustment pin guide hole 34 and the pin insertion hole 6b in the connection side recess 6a of the connector part 6 are assembled so as to be coaxial. The adjustment pin guide hole 34 may be formed by, for example, burring, and the processing method is not particularly limited.

  The adjustment pin guide member 30 may be bent at a part of the fixed terminal 12, but is made of a metal material different from the fixed terminal 12 and fixed to the one end 12 a of the fixed terminal 12. May be.

  In the pressure switch 2 having such a configuration, the pin insertion hole 6b of the connector portion 6 made of resin such as PPS is caused by thermal expansion or contraction due to a change in operating temperature, for example, a temperature change of −40 ° C. to + 150 ° C. Even if a gap is generated between the metal pin and the metal adjustment pin 24 and a so-called rattling occurs, the adjustment pin guide hole 34 of the adjustment pin guide member 30 for fixing the adjustment pin 24, for example, by press fitting or the like. Since the fixing load of the adjusting pin 24 is not lowered and the position of the operating shaft 20 is not shifted, the operating point (operating pressure) is not shifted. Yes.

  In addition, since the adjustment pin guide member 30 is made of metal, the adjustment pin 24 and the adjustment pin guide member 30 are metal-fitted, so even if there is a temperature change, thermal expansion and contraction are caused. Since the ratio is almost the same, no gap is generated between the adjustment pin 24 and the adjustment pin guide member 30, and so-called rattling does not occur, so that the pressing load of the adjustment pin 24 does not decrease, Since the position of the operating shaft 20 does not shift, the operating point (operating pressure) does not shift.

  Further, when the adjustment pin 24 and the adjustment pin guide member 30 are metal-to-metal fittings, even if there is a change in temperature, if the adjustment pin 24 and the adjustment pin guide member 30 are used within the elasticity of the metal, they return to the same holding force when returning to normal temperature. Therefore, the pressing load of the adjustment pin 24 does not decrease and the position of the operating shaft 20 does not shift, so that the operating point (operating pressure) does not shift.

  Further, if the adjustment pin 24 and the adjustment pin guide hole 34 are arranged coaxially, the adjustment pin 24 is fitted into the adjustment pin guide hole 34, and the adjustment pin 24 is fixed by, for example, press fitting. Good, simple structure and easy assembly work.

In this case, the adjustment pin 24 is not provided with the hollow hole 24a, but a gap is provided between the pin insertion hole 6b of the connector portion 6 and the metal adjustment pin 24, and the gap is provided via this gap. You may comprise so that the pressure in the joint part 4, ie, the contact operation chamber 14, may be maintained substantially the same pressure as an outward pressure. That is, since the adjustment pin 24 is fixed by the adjustment pin guide member 30 and so-called rattling is prevented, a gap is provided between the pin insertion hole 6b of the connector portion 6 and the metal adjustment pin 24. This is because the pressing load of the adjusting pin 24 does not decrease and the position of the operating shaft 20 does not shift, so that the operating point (operating pressure) does not shift.

  Further, a hollow hole 24 a may be provided in the adjustment pin 24, and a gap may be provided between the pin insertion hole 6 b of the connector portion 6 and the metal adjustment pin 24.

  In the above embodiment, the adjustment pin 24 is hollow and the hollow hole 24a is provided so that the pressure outside the contact operation chamber 14 is maintained at substantially the same pressure. However, although not shown, the upper opening of the hollow hole 24a of the adjustment pin 24 and the gap between the pin insertion hole 6b of the connector 6 and the adjustment pin 24 can be sealed with resin.

  In this case, it is desirable to provide a gap between the fixed terminal 12 and the connector portion 6 and maintain the contact operating chamber 14 and the external pressure at substantially the same pressure via this gap.

  The preferred embodiment of the present invention has been described above. However, the present invention is not limited to this. For example, in the above embodiment, the pressure switch is used as a switch for detecting the hydraulic pressure of the transmission of an automobile. However, instead of this, for example, it can also be used to detect whether the lubricating oil pressure is appropriate.

  Further, in the above-described embodiment, it can be preferably used for low pressure, particularly for detection of fine pressure, but can be applied to detection of a relatively large pressure if a metal diaphragm is appropriately selected.

  Furthermore, in the said Example, although the conductive path from the fixed terminal 12 to the movable member 16 (elastic arm 18, operating shaft 20), the metal diaphragm 10, and the joint part 4 was formed, from the fixed terminal 12, It is also possible to form a conductive path outside the pressure switch through another path, such as by providing a takeout terminal or the like through the movable member 16 (elastic arm 18, operating shaft 20) and the metal diaphragm 10. Various modifications can be made without departing from the scope of the present invention.

FIG. 1 is a schematic longitudinal sectional view showing an embodiment of the pressure switch of the present invention. FIG. 2 is a partially enlarged cross-sectional view showing a positional relationship of operating points (operating pressures) of the pressure switch of FIG. 3 is a partial enlarged cross-sectional view showing the positional relationship of the ON state of the switch of the pressure switch of FIG. FIG. 4 is a diagram showing pressure-displacement characteristics of a metal diaphragm. FIG. 5 is a schematic longitudinal sectional view showing another embodiment of the pressure switch of the present invention. FIG. 6 is a schematic longitudinal sectional view of a pressure switch using a conventional rubber diaphragm.

Explanation of symbols

2 Pressure switch 4 Joint portion 6 Connector portion 6a Connection side recess 6b Pin insertion hole 8 Pressure chamber 10 Metal diaphragm 12 Fixed terminal 12a Tip portion 14 Contact operation chamber 15 Caulking 16 Movable member 18 Elastic arm 20 Actuation shaft 22 Stopper member 22a Opening 24 Adjustment pin 24a Hollow hole 26 Guide slope 27 Adhesive 28 O-ring 29 O-ring 30 Adjustment pin guide member 32 Adjustment pin guide member main body 34 Adjustment pin guide hole 60 Vehicle equipment 61 Fixing portion 62 Joint portion 63 Connector portion 64 Diaphragm 65 Movable contact 66 Compression coil spring 67 Metal member 68 Fixed contact 69 Pressure chamber 70 Pressure switch P1 Operating pressure s Gap t Operating point position U Upper position X position

Claims (8)

Conductive joints,
An insulating connector part joined to the joint part;
A fixed terminal disposed in the connector portion;
A metal diaphragm disposed in the joint and operating in response to pressure;
A conductive movable member disposed above the metal diaphragm and having one end connected to a fixed terminal;
When the pressure applied to the metal diaphragm is equal to or higher than a predetermined pressure, the metal diaphragm comes into contact with the other end of the movable member to reach the movable member, the metal diaphragm, and the joint portion from the fixed terminal. A pressure switch, characterized in that a conductive path is formed. The movable member is
An elastic arm having one end fixed to the fixed terminal;
2. The pressure according to claim 1, further comprising: an operating shaft fixed to the elastic arm and abutting the metal diaphragm when a pressure applied to the metal diaphragm becomes equal to or higher than a predetermined pressure. switch. A position adjusting means for adjusting a distance between a tip of the operating shaft and a substantially central portion of the metal diaphragm;
The pressure switch according to claim 2, wherein the position adjusting unit includes an adjustment pin that is movably mounted in the joint portion from the connector portion.   The pressure switch according to claim 3, wherein an adjustment pin guide member for fixing the adjustment pin is formed at one end of the fixed terminal on the joint part side. The adjustment pin guide member is
An adjustment pin guide member body bent into a substantially L shape from one end of the fixed terminal on the joint part side;
The pressure switch according to claim 4, wherein the pressure switch is formed of an adjustment pin guide hole formed in the adjustment pin guide member main body and fixing the adjustment pin.   6. The structure according to claim 3, wherein the adjustment pin is formed in a hollow shape so that the pressure in the joint portion is maintained at substantially the same pressure as the outward pressure. The pressure switch described in.   The pressure switch according to any one of claims 2 to 6, wherein the elastic arm has a substantially J-shaped cross section. A method for adjusting an operating point in a pressure switch according to any one of claims 3 to 7,
While applying a predetermined pressure to the metal diaphragm and moving the adjustment pin of the position adjusting means downward,
Move the operating shaft downward, the operating shaft abuts the metal diaphragm, and the position of the operating shaft at the time when conduction from the fixed terminal to the movable member, the metal diaphragm, and the joint is secured is activated. A method for adjusting an operating point in a pressure switch, wherein the adjustment is performed so that the position of the tip of the shaft is located.

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