JP2005302629A - Mechanism for attenuating oil pressure pulsation of oil pressure switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism for attenuating oil pressure pulsation of an oil pressure switch for the purpose of preventing chattering occurring at a point of contact of the oil pressure switch by means of pressure pulsation of an engine lubricating oil. <P>SOLUTION: The mechanism for attenuating oil pressure pulsation of an oil pressure switch has an adaptor (3) for connecting an engine to the oil pressure switch (20). A channel (2f) for transmitting the engine oil pressure within the engine to the oil pressure switch (20) is formed inside the adaptor (3). A pulsation attenuation member (10) is housed in the channel (2f), and is closely fitted to the channel (2f). Moreover, a spirally shaped groove (12) is formed on the outer periphery surface (10s) of the pulsation attenuation member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydraulic pulsation damping mechanism of an oil pressure switch in which a switch is operated at a predetermined hydraulic pressure by detecting the hydraulic pressure of engine lubricating oil that fluctuates with pulsation.

  FIG. 11 shows the mounting position of a conventional oil pressure switch 20 for detecting the oil pressure of the lubricating oil of the engine. In this example, the screw hole of the boss part leading to the oil passage formed on the side surface of the cylinder block Be is the oil pressure. The switch 20 is configured to be screwed into the taper screw 22.

  FIG. 12 shows an oil pressure switch 20, which has a diaphragm 23 biased by a spring at a diameter-enlarged portion of a chamber 24 that leads to a passage provided in a taper screw 22 that is screwed into the cylinder block Be. An ON-OFF type contact 24 is provided.

  The oil pressure switch 20 is configured such that the contact 24 opens as the engine oil pressure increases and closes when the oil pressure decreases, and is provided for the purpose of avoiding the lubricating oil pressure exceeding a predetermined oil pressure. It has been.

  As described above, the diaphragm 23 directly receives the engine hydraulic pressure, and thus has an advantage of good responsiveness. On the other hand, since the precise hydraulic fluctuation is faithfully picked up as it is, the switch is turned on or off even if it is harmless to the engine. For example, it is frequently repeated due to pressure pulsation generated by the oil pump or pressure pulsation due to fluctuations in the rotational speed of the engine.

  If there is a hydraulic pulsation in the vicinity of a predetermined engine oil pressure that is unavoidable as a hydraulic system, contact 24 is frequently contacted and separated, and an arc is generated between the contacts by so-called chattering to oxidize the contacts. There is a concern that an object will be generated, and as a result, it will develop into poor contact conduction.

  As means for avoiding pressure pulsation of engine hydraulic pressure, for example, an elastic tube that absorbs pressure pulsation by expanding the diameter or a tube that absorbs pressure pulsation by passage resistance, etc. are conceivable, but it is practical to apply to a limited engine room space Not established.

There are various conventional techniques for avoiding malfunction of the oil pressure switch (see, for example, Patent Document 1). However, all of them are techniques for improving the malfunction of the diaphragm, for example, and are not techniques for suppressing chattering at the contacts.
Sho 63-20039

  The present invention has been proposed in view of the above-described problems of the prior art, and provides a hydraulic pulsation damping mechanism for an oil pressure switch for preventing chattering on the contact of the oil pressure switch due to pressure pulsation of engine lubricating oil. It is an object.

As a result of various studies, the inventor has been able to obtain a technique that does not cause a layout problem by attaching an adapter provided with a hydraulic passage for reducing hydraulic pulsation between the oil pressure switch and the engine.
The present invention has been created based on such knowledge.

  That is, according to the hydraulic pulsation damping mechanism of the oil pressure switch of the present invention, the adapter (3) for connecting the engine and the oil pressure switch (20) is provided, and the engine oil pressure in the engine is controlled by the oil pressure switch (20). A flow path (2f) for transmission to the adapter (3) is formed inside the adapter (3), a pulsation damping member (10) is accommodated in the flow path (2f), and the pulsation damping member (10) Is tightly fitted in the flow path (2f), and a spiral groove (12) is formed on the outer peripheral surface (10s) (claim 1).

The spiral groove (12) has a function of attenuating pulsation, and there is no risk of blockage due to the entry of foreign matter, so that the engine oil pressure inside the engine can be transmitted to such an extent that the oil pressure switch (20) operates reliably. (Cross sectional area and sectional shape) are preferably set (claim 2).
In implementation, the spiral grooves may be 1 mm wide and 1 mm deep, for example, with an appropriate pitch.

It is preferable that a plurality of the spiral grooves (12) are formed (Claim 3).
In the implementation, about 2 is preferable.

Further, it is preferable that the spiral groove (C1) constituting the right spiral and the spiral groove (C2) constituting the left spiral are formed. .
In implementation, the pitch of the spiral groove of the right spiral and the pitch of the spiral groove of the left spiral may be different, and the shape of the groove may be different.

It is preferable that the pulsation damping member (10) is constituted by a stud bolt (10C).
The stud bolt in the above refers to a bolt having no head and having a screw formed over its entire length.

  Since an adapter that is fitted with a pulsation damping member provided with a spiral groove between the engine and the oil pressure switch is interposed, and a spiral groove is provided on the outer periphery of the adapter (Claim 1), The pressure pulsation of the engine hydraulic pressure is attenuated by a groove serving as a flow path and reaches the oil pressure switch, and there is no contact failure due to chattering.

  Since the spiral groove has an effect of damping the pulsation of pressure entering the oil pressure switch, there is no risk of foreign matter intrusion, and the oil pressure switch can be operated reliably (Claim 2). In addition, there is no contact failure due to hydraulic pulsation to the oil pressure switch and no hydraulic transmission failure caused by blockage of the flow path by foreign matter.

  Further, since the spiral groove is formed with a plurality of strips (Claim 3), even if one groove is closed for some reason, pressure transmission and pulsation attenuation are guaranteed by the other groove.

  Further, since the spiral groove is composed of a right-hand spiral and a left-hand spiral (Claim 4), pulsation interferes at the intersection and further pulsation attenuation is performed.

  Since the pulsation damping member is formed of a stud bolt (Claim 5), it is possible to reduce the cost with a general-purpose product without setting a dedicated part.

  Since the adapter is formed so as to be attachable to a conventional oil pressure switch, the screw hole machining of the cylinder block is not changed, and there is no additional work on the oil pressure switch, so that the cost is low and the attachment is easy.

  Hereinafter, an embodiment of a hydraulic pulsation damping mechanism of an oil pressure switch of the present invention will be described with reference to the drawings.

FIG. 1 shows an overall side cross section of the hydraulic pulsation damping mechanism, and FIG. 2 shows a front view thereof.
In FIG. 1, the hydraulic pulsation damping mechanism includes a rod-shaped adapter 3 with a head and a pulsation damping member 10 arranged inside the adapter 3.

  1 and FIG. 3 showing a single unit, the adapter 3 includes a hexagonal bolt head 7, a round bar-shaped bar 3 a, and a small-diameter screw provided at the end of the bar 3 a via a shoulder 3 b. The outer structure is integrally formed with the portion 4. The total length is 50-60 mm which is practically acceptable.

  The screwed portion 4 is provided with a 1 / 8-28 threaded taper screw portion 4a that is compatible with a screwed portion of a conventionally used oil pressure switch.

  An inner taper screw 8 that is screwed into the screwed portion 22 of the oil pressure switch 20 is formed inside the adapter 3 in the vicinity of the bolt head 7, and an inner hole that is connected to the inner taper screw 8 in the vicinity of the rod-shaped portion 3a. In this example of a small diameter, an oil passage 5 of φ = 1.5 mm is connected to the inner hole 6 in the vicinity of the screw-in portion 4.

The inner hole 6 and the oil passage 5 are connected by a tapered portion 6a, and are formed so as to provide a gap so that the end portion of the pulsation damping member 10 does not block the flow path 2f.
The inner hole 6, the oil passage 5, and the taper screw hole 8 form a hydraulic transmission channel 2f, and a substantial transmission channel is formed by a spiral groove provided in the damping member 10 described below. .

  FIG. 4 shows the damping member 10, and the outer peripheral surface is formed with a size that is fitted into the inner diameter of the inner hole 6 of the adapter 3 by an interference fit, and a spiral groove 12 is formed on the outer diameter over the entire length. ing. Chamfering Cm is formed at both ends of the attenuation member 10.

  FIG. 5 shows the cross-sectional shape of the spiral groove 12 of the damping member 10 perpendicular to the groove, and the grooves 12 are formed at an appropriate pitch p on the outer peripheral surface 11 fitted into the inner hole 6 of the adapter 3. In this example, the groove width b and the groove depth h are each 1 mm. The entire length of the damping member 10 is formed substantially equal to the length of the inner hole 6. The length of the damping member 10 is configured to be as short as possible together with the adapter 3 within a range in which the damping function is performed, so as to avoid interference with other parts in a narrow engine room.

  In FIG. 6, the spiral groove 12 is formed in a thread groove shape, and the V-shaped groove 12 a is formed at an appropriate pitch p <b> 1 on the outer peripheral surface 11 a that fits in the inner hole 6 of the adapter 3. In this example, b1 and groove depth h1 are each 1 mm.

  The groove pitches p and p1 and the groove shape are not limited to the above, and may be arbitrary as long as the cross-sectional area and the cross-sectional shape are appropriate. If the sectional area of the groove is small, the pulsation damping force is large as it is, and the amplitude of the pulsation can be reduced.

The assembly of the pulsation damping member 10 to the adapter 3 returns to FIG. 1, and the pulsation damping member 10 is pushed into the inner hole 6 of the adapter 3 so as to be tightly fitted to constitute a hydraulic pulsation damping mechanism. . Due to the interference fit of the pulsation damping member 10, the pulsation damping member 10 does not move in the inner hole 6 due to engine vibration or vehicle vibration.
Pushing of the pulsation damping member 10 into the inner hole 6 is arranged such that an appropriate gap d is secured between the end of the pulsation damping member 10 and the tapered portion 6a.

FIG. 7 is a perspective view showing a state in which the hydraulic pulsation damping mechanism is attached to the cylinder block Be of the engine.
The threaded portion 4 of the adapter 3 is screwed into the inner taper screw of the cylinder block Be, and the oil pressure switch 20 is screwed into the taper screw hole of the adapter 3 to perform the function of detecting the pressure of engine lubricating oil. Yes.

  FIG. 8 shows another form of the pulsation damping member 10, and spiral grooves are formed in parallel between the first groove C1 and the second groove C2. In this example, the pitches p1 of the first and second grooves C1, C2 are equal to each other, that is, the spiral angles are equal, and the interval between the first and second grooves C1, C2 is p / 2, but the pitches are unequal. Alternatively, the shapes of the grooves C1 and C2 may not be the same.

  FIG. 9 shows still another form of the pulsation damping member 10, wherein the spiral groove is formed by a rightward groove D1 and a leftward groove D2 formed of a right spiral and a left spiral in reverse spirals. And are formed to cross each other. Although the pitches of the right and left grooves D1 and D2 are equal in this example, the pitches of the grooves D1 and D2 do not have to be the same.

  FIG. 10 shows still another form of the pulsation damping member 10, and the stud bolt 10 </ b> C used for a normal implantation bolt is used as it is as a pulsation damping member. A valley portion of the screw S becomes a V groove similar to that shown in FIG.

  Due to the hydraulic pulsation damping mechanism, the hydraulic pulsation in the engine is caused by the oil passage 5 of the adapter 3 and the helical groove 12 of the pulsation damping member 10 so that the amplitude of the pulsation is attenuated and the maximum pressure is lowered, causing no harm. The contact opening and closing of the oil pressure switch 20 at normal pressure is suppressed, and chattering is suppressed.

It should be noted that the illustrated embodiment is merely an example, and is not intended to limit the technical scope of the present invention.
For example, a hydraulic pulsation damping mechanism using the adapter 3 of the present invention can be used for an oil motor or its conduit to protect the contact point of an oil pressure switch, or to prevent a failure caused by a pulse pressure of a Bourdon tube. Applicable.

The sectional side view of the adapter which comprises the hydraulic pulsation damping mechanism of the oil pressure switch of this invention. The A arrow directional view of FIG. FIG. 2 is a side sectional view of the adapter of FIG. It is a side view of the member for pulsation attenuation. The figure which shows the structure of the groove | channel of FIG. The figure which shows another structure of the groove | channel of FIG. FIG. 2 is a perspective view showing a state where the hydraulic pulsation damping mechanism of FIG. 1 is attached to an engine cylinder block. The figure which shows another form of the member for pulsation attenuation | damping. The figure which shows another form of the member for pulsation attenuation | damping. The figure which shows another form of the member for pulsation attenuation | damping. The figure which shows the position of the engine in which an oil pressure switch is attached. The side sectional view of an oil pressure switch.

Explanation of symbols

Be ... cylinder block 2f ... flow path 3 ... adapter 3a ... rod-like part 4 ... screwed-in part 4a ... taper screw part 5 ... oil passage 6 ... inner hole 7. ..Bolt head 8 ... Tapered screw hole 10 ... Pulsation damping member 11, 11a ... Outer peripheral surface 12 ... Groove 20 ... Oil pressure switch

Claims (5)

It has an adapter that connects the engine and the oil pressure switch. A flow path for transmitting engine oil pressure in the engine to the oil pressure switch is formed inside the adapter, and a pulsation damping member is accommodated in the flow path. A hydraulic pulsation damping mechanism for an oil pressure switch, characterized in that the pulsation damping member is tightly fitted in the flow path, and a spiral groove is formed on the outer peripheral surface. The spiral groove has a function of attenuating pulsation and is set so as to transmit the engine oil pressure inside the engine to such an extent that the oil pressure switch can be surely operated without the possibility of blockage due to foreign matter intrusion. The oil pressure switch hydraulic pulsation damping mechanism according to Item 1. The hydraulic pulsation damping mechanism for an oil pressure switch according to any one of claims 1 and 2, wherein a plurality of spiral grooves are formed. The hydraulic pulsation damping mechanism for an oil pressure switch according to claim 3, wherein the spiral groove forming a right spiral and the spiral groove forming a left spiral are formed. The hydraulic pulsation damping mechanism for an oil pressure switch according to any one of claims 1 to 3, wherein the pulsation damping member comprises a stud bolt.

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