JP2010261374A - Vacuum pump - Google Patents

Abstract

An object of the present invention is to reduce operating noise in a vacuum pump.
The vacuum pump is provided in relation to a discharge port 24 opened on the outer side of the rotor on the downstream side in the rotation direction of the vane, and an opening of the discharge port 24, and the pressure of the compressed air discharged is increased or decreased. And a reed valve 30 for opening and closing the discharge port 24 according to the above. The reed valve 30 is a butterfly type, and includes a thin plate-like valve body 32 that covers the discharge port 24 and a stopper 34 that restricts the opening range of the valve body 32, and the base end of the stopper 34 is the valve body 32. It is fixed to the housing surface 36 in a state where it is overlaid on the base end. The stopper 34 is made of a bimetal configured to shift the resonance frequency to the high frequency side.
[Selection] Figure 3

Description

  The present invention relates to a vacuum pump mounted on a vehicle, and more particularly, to a vane type vacuum pump.

  For example, Patent Document 1 proposes a vacuum pump that enables a smooth start.

  The vacuum pump described in Patent Document 1 is provided with a check valve for preventing oil inflow from the outside in the discharge passage of the pump chamber. The check valve has a valve body arranged in the discharge passage, and when the pressure higher than the predetermined pressure is applied from the pump chamber side, the valve body moves and opens, and when the temperature becomes low below the predetermined temperature. In addition, the valve body is deformed and opens.

  Patent Document 2 proposes a vacuum pump that prevents the exhaust valve from sticking at a low temperature.

  In the vacuum pump described in Patent Document 2, an exhaust hole for discharging the exhaust from the pump chamber is formed in the housing. The thin plate-like exhaust valve contacts the seating surface around the exhaust hole and closes the exhaust hole. One end of the exhaust valve is fixed to the seat surface, and the other end is configured to be opened by being pushed up by the pressure of the exhaust discharged from the exhaust hole. A bottomed hole is provided in the contact surface between the exhaust valve and the seat surface, and a rod body having a smaller linear expansion coefficient than the housing protrudes from the bottom of the bottomed hole. The length of the rod body is set so that the tip of the rod body protrudes from the seat surface at a low temperature, and the whole rod body is accommodated in the bottomed hole by the expansion of the bottomed hole at a high temperature.

JP 2005-16353 A JP 2005-226536 A

  By the way, in order to reduce the operating noise of the vane type vacuum pump, it is necessary to lower the pump internal pressure peak at the time of discharge. As one of the methods, it has been confirmed that a leak groove is provided in the discharge port. However, as a contradiction, there are an increase in the driving torque of the vacuum pump (deterioration of fuel consumption) and an increase in consumption of lubricating oil. The mechanism will be described below.

  Regarding the operating noise, the pump internal pressure increases due to the compression of the air and the pump, and the discharge noise of the compressed air and the lubricating oil increases accordingly.

  Regarding the driving torque, the differential pressure across the vane increases due to the suction of air from the leak groove, and the driving torque increases accordingly.

  Concerning the consumption of the lubricating oil, oil mist is generated in the pump due to atmospheric suction from the leak groove, and the consumption of the lubricating oil increases accordingly.

  The present invention has been made in view of such a background, and an object thereof is to provide a vacuum pump capable of reducing operating noise.

  In order to achieve the above object, a vacuum pump according to the present invention includes a discharge port that is opened downstream of the rotor in the rotational direction of the vane, and a compression that is provided in association with the opening of the discharge port and discharged. A vacuum pump comprising a reed valve that opens and closes a discharge port according to an increase or decrease in air pressure, wherein the reed valve is of a butterfly type, and a thin plate-like valve body that covers the discharge port; Including a stopper that regulates the opening range of the valve body, and is fixed to the housing surface with the base end of the stopper overlaid on the base end of the valve body, so that the stopper shifts the resonance frequency to the high frequency side. It consists of a constructed bimetal.

  In a vacuum pump, if the pump internal pressure increases due to oil compression during discharge, the stopper of the reed valve resonates during oil discharge, increasing the operating noise.

  On the other hand, in the above configuration, since the bimetal configured to shift the resonance frequency to the high frequency side is used as a reed valve stopper, the resonance frequency of the stopper with respect to the peak frequency of the generated operating noise. Can be shifted to the high frequency side. Therefore, resonance of the stopper is prevented. As a result, the operating noise is reduced.

  By the way, when the oil temperature is low, it is preferable that the height from the housing surface to the free end of the stopper is large from the viewpoint of oil drainage. If this height is small, the internal pressure of the pump becomes large and the pump itself may be damaged. Further, when the oil temperature is high, if the above height is large, there is a concern that the fatigue strength of the reed valve is deteriorated.

  Therefore, in the vacuum pump, the height dimension from the housing surface to the free end of the stopper is larger when the oil temperature is lower than when the oil temperature is higher due to temperature-sensitive deformation due to the temperature of the bimetal. It is trying to become.

  According to the present invention, it is possible to provide a vacuum pump that can reduce operating noise.

It is a figure which shows the mechanical structure of the vacuum pump of the vehicle concerning embodiment of this invention. FIG. 2 is an enlarged view of the U portion of FIG. It is sectional drawing which follows the XX line of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a mechanical configuration of a vacuum pump 10 for a vehicle according to an embodiment of the present invention, FIG. 2 is an enlarged view showing a U portion of FIG. 1, and FIG. 3 is an XX line in FIG. It is sectional drawing which follows.

  As shown in FIG. 1, the vacuum pump 10 of the present embodiment is a single-sheet through-vane vacuum pump, and includes a housing 12, a rotor 14 that rotates eccentrically in the housing 12, and a diameter of the rotor 14. And a vane 16 slidably supported in the direction.

  The main body 18 of the housing 12 has an elliptical bottomed cylindrical shape. In the housing main body 18, a pump chamber 22 on the suction port 20 side and a pump chamber 26 on the discharge port 24 side are partitioned by the inner peripheral surface, the outer peripheral surface of the rotor 14, and the vane 16. The volume of the two pump chambers 22 and 26 is changed when the vane 16 is rotated clockwise as indicated by an arrow R in FIG.

  The discharge port 24 is open to the G point side, which is the downstream side in the rotational direction R of the vane 16 and the point at which the rotor 14 and the housing body 18 are closest to each other outside the rotor 14. As shown in FIG. 2, the discharge port 24 is curved along the outer peripheral edge portion of the rotor 14.

  As shown in FIG. 1, the suction port 20 is provided outside the housing body 18 on the side opposite to the discharge port 24 with the vane 16 interposed therebetween.

  The rotor 14 has a thick bottomed cylindrical shape. A vane groove 28 is formed on the outer peripheral surface of the rotor 14, and the vane 16 is fitted in the vane groove 28 so as to be slidable in the radial direction of the rotor 14.

  The vane 16 is provided in the rotor 14 so that the tip thereof can move along the inner peripheral surfaces of the pump chambers 22 and 26. Specifically, the vane 16 receives a centrifugal force in a direction protruding from the vane groove 28 as the rotor 14 rotates. Thus, the vane 16 enters and exits the vane groove 28 while the outer peripheral edge of the vane 16 and the inner peripheral surfaces of the pump chambers 22 and 26 are in sliding contact. Thus, a gap whose width dimension continuously changes along the circumferential direction is formed between the inner peripheral surfaces of the pump chambers 22 and 26 that are eccentric to each other and the outer peripheral surface of the rotor 14.

  Further, in the present vacuum pump 10, as shown in FIG. 3, a reed valve 30 that is provided in association with the opening of the discharge port 24 and opens and closes the discharge port 24 according to the increase or decrease of the pressure of the compressed air discharged is provided. Is provided.

  The reed valve 30 is of a butterfly type, and includes a valve body 32 made of a thin leaf spring that covers the discharge port 24 and a stopper 34 that restricts the opening range of the valve body 32. The base end of the stopper 34 is screwed to the housing surface 36 so as to overlap the base end of the valve body 32.

  The stopper 34 is made of bimetal. This bimetal is formed by bonding two types of metal plates having different thermal expansion coefficients into a single plate, and is configured to shift the resonance frequency to the high frequency side regardless of the engine oil temperature. In other words, the bimetal thickness is set so that resonance does not occur even when the internal pressure of the vacuum pump 10 increases.

  Further, in the vacuum pump 10, the height from the housing surface 36 to the free end of the stopper 34 is high when the oil temperature is high due to temperature-sensitive deformation (curvature deformation) due to the temperature of the bimetal. The height dimension h2 at a low temperature is larger than the height dimension h1.

  In the vacuum pump 10, when the internal pressure of the vacuum pump 10 increases due to compression of the engine oil at the time of discharge, the stopper 34 of the reed valve 30 resonates during engine oil discharge, and the operating noise increases.

  In contrast, in the present embodiment, the stopper 34 of the reed valve 30 is a bimetal configured to shift the resonance frequency to the high frequency side regardless of the oil temperature (in other words, the internal pressure of the vacuum pump 10 is reduced). Since the thickness is set so that it does not resonate even if it is increased, the bimetal is used, so that the resonance frequency of the stopper 34 can be shifted to the high frequency side with respect to the peak frequency of the generated operating sound. Therefore, resonance of the stopper 34 is prevented. As a result, the operating noise is reduced.

  Further, when the engine oil temperature is low, if the height from the housing surface 36 to the free end of the stopper 34 is small due to its oil discharge property, the internal pressure of the vacuum pump 10 becomes large and the vacuum pump 10 itself is damaged. There is a fear. Conversely, when the oil temperature is high, there is a concern that the fatigue strength of the reed valve 30 may deteriorate if the height is large.

  On the other hand, in the present embodiment, the height dimension from the housing surface 36 to the free end of the stopper 34 is high when the engine oil temperature is high due to the curved deformation due to the temperature of the bimetal constituting the stopper 34. Since the height h2 at the low temperature is larger than the height h1, there is no possibility that the vacuum pump 10 itself is damaged or the fatigue strength of the reed valve 30 is deteriorated. .

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various design changes and modifications can be made within the scope of the appended claims.

10 Vacuum pump 14 Rotor 16 Vane 24 Discharge port 30 Reed valve 32 Valve body 34 Stopper 36 Housing surface

Claims (2)

A discharge port that is opened downstream of the rotor in the rotational direction of the vane and a reed valve that is provided in association with the opening of the discharge port and opens and closes the discharge port according to the increase or decrease of the pressure of the compressed air to be discharged A vacuum pump comprising:
The reed valve is a butterfly type, and includes a thin plate-like valve body that covers the discharge port, and a stopper that regulates the opening range of the valve body, and the base end of the stopper is on the base end of the valve body. It is fixed to the housing surface in a stacked state,
The vacuum pump is characterized in that the stopper is made of a bimetal configured to shift the resonance frequency to the high frequency side. The vacuum pump according to claim 1,
The height dimension from the housing surface to the free end of the stopper is such that the oil temperature is lower than the high temperature due to temperature-sensitive deformation due to the temperature of the bimetal. Features vacuum pump.

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