JP2020076340A - pump - Google Patents

Abstract

To provide a pump capable of reducing noise due to pulse.SOLUTION: A pump comprises: a pump unit 4 that transfers a fluid; a first silencing chamber provided on the downstream side of the pump unit 4; a first passage that is provided on the downstream side of the pump unit 4 and guides the fluid to the first silencing chamber; and a second passage that is arranged in parallel to a first passage on the downstream side of the pump unit 4 and guides the fluid to the first silencing chamber. At least one of a passage length and a passage diameter is different between the first passage and the second passage.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to pumps.

  Patent Document 1 discloses an electric vacuum pump for making a negative pressure in a negative pressure chamber of a brake booster in a vehicle such as an automobile. The pump described in Patent Document 1 includes a muffling chamber (silencer section) for reducing exhaust noise that accompanies the operation of the pump section for transferring a fluid. This muffler chamber functions as an expansion muffler and reduces exhaust noise by compressing or expanding the fluid between the discharge port of the pump section and the discharge port for discharging the discharge fluid to the outside. To do.

JP, 2005-81585, A

  By the way, the noise of the pump tends to increase at a specific frequency due to pulsation. In particular, as the size of the pump increases and the volume of the pump increases, noise of a specific frequency due to pulsation tends to stand out.

  In this respect, the expansion silencer as described in Patent Document 1 can gradually reduce the sound pressure level in a wide frequency range, but the effect of reducing the sound pressure level at a specific frequency due to pulsation is limited. Target. Further, the frequency due to pulsation is a relatively low frequency, and the method using a sound absorbing material has a limited effect of attenuating noise.

  At least one embodiment of the present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a pump capable of reducing noise due to pulsation.

(1) A pump according to at least one embodiment of the present invention is
A pump unit for transferring a fluid,
A first silencing chamber provided on the downstream side of the pump section,
A first passage that is provided on the downstream side of the pump portion and guides the fluid to the first silencing chamber;
A second passage that is arranged in parallel to the first passage on the downstream side of the pump portion and guides the fluid to the first silencing chamber;
Equipped with
At least one of the passage length and the passage diameter is different between the first passage and the second passage.

  In the above configuration (1), the first silencing chamber may be, for example, the silencing chamber 12 described later, the upstream silencing chamber 18 described later, or the downstream silencing chamber 20 described later. It may be. When the first silencing chamber is the silencing chamber 12, the first passage may be, for example, one of the passage 14 and the passage 16 described later, and the second passage may be, for example, the other of the passage 14 and the passage 16. May be. When the first silencing chamber is the upstream silencing chamber 18, the first passage may be, for example, one of the passage 28 and the passage 30 described later, and the second passage may be the other of the passage 28 and the passage 30. May be When the first silencing chamber is the downstream silencing chamber 20, the first passage may be, for example, one of the passage 24 and the passage 26 described later, and the second passage may be the other of the passage 24 and the passage 26, for example. May be

(2) In some embodiments, in the pump described in (1) above,
Further comprising a second silencing chamber provided on the downstream side of the pump section,
Each of the first passage and the second passage may connect the first silencing chamber and the second silencing chamber.

  In the configuration of (2) above, the second silencing chamber may be, for example, one of an upstream silencing chamber 18 and a downstream silencing chamber 20 described below, and the first silencing chamber may be, for example, the upstream silencing chamber. The other of the silencing chamber 18 and the downstream silencing chamber 20 may be provided. Further, the first passage may be, for example, one of the passage 24 and the passage 26 described below, and the second passage may be, for example, the other of the passage 24 and the passage 26.

(3) In some embodiments, in the pump described in (2) above,
The second silencing chamber is provided above the first silencing chamber,
A first cylindrical portion protruding downward is provided on the ceiling wall of the first silencing chamber,
The first passage may connect the first silencing chamber and the second silencing chamber via the internal space of the first tubular portion.

  In the above configuration (3), the first silencing chamber may be, for example, the upstream silencing chamber 18 described later, and the second silencing chamber may be, for example, the downstream silencing chamber 20 described later. Further, the first tubular portion may be, for example, the tubular portion 60 described later or the tubular portion 62.

(4) In some embodiments, in the pump described in (3) above,
A second tubular portion is formed on the ceiling wall portion so as to project downward,
The second passage connects the first silencing chamber and the second silencing chamber through the internal space of the second tubular portion,
The protrusion amount of the first tubular portion and the protrusion amount of the second tubular portion may be different.

  In the configuration of (4) above, the first tubular portion may be, for example, one of a tubular portion 60 and a tubular portion 62 described later, and the second tubular portion may be, for example, the tubular portion 60 and the tubular portion. It may be the other of the shaped portions 62.

(5) In some embodiments, in the pump described in (4) above,
The ceiling wall portion, the first tubular portion, and the second tubular portion may be integrally formed of the same material.

(6) In some embodiments, in the pump according to any one of (2) to (5) above,
A third passage connecting the pump portion and the second silencing chamber, and a fourth passage arranged in parallel with the third passage and connecting the pump portion and the second silencing chamber. Prepare,
At least one of the passage length and the passage diameter may be different between the third passage and the fourth passage.

  In the configuration of (6) above, the third passage may be, for example, one of the passage 28 and the passage 30 described below, and the fourth passage may be, for example, the other of the passage 28 and the passage 30.

(7) In some embodiments, in the pump described in (1) above,
Each of the first passage and the second passage may connect the pump unit and the first silencing chamber.

  In the above configuration (7), the first silencing chamber may be, for example, the silencing chamber 12 described later or the upstream silencing chamber 18 described later. When the first silencing chamber is the silencing chamber 12, the first passage may be, for example, one of the passage 14 and the passage 16 described below, and the second passage may be, for example, the other of the passage 14 and the passage 16. It may be. When the first silencing chamber is the upstream silencing chamber 18, the first passage may be, for example, one of the passage 28 and the passage 30 described later, or the second passage may be, for example, the passage 28 and the passage 30. It may be the other.

(8) In some embodiments, in the pump according to (7) above,
The first silencing chamber is provided below the pump section,
A first cylindrical portion that protrudes downward is formed on the ceiling wall of the first silencing chamber,
The first passage may connect the pump portion and the first silencing chamber via the internal space of the first tubular portion.

  In the above configuration (8), the first silencing chamber may be, for example, the upstream silencing chamber 18 described later. The first passage may be one of the passage 28 and the passage 30 described later, for example. When the first passage is the passage 28, the first tubular portion may be, for example, the tubular portion 54 described later. When the first passage is the passage 30, the first tubular portion may be, for example, a tubular portion 56 described later.

(9) In some embodiments, in the pump described in (8) above,
A second tubular portion is formed on the ceiling wall portion so as to project downward,
The second passage connects the pump portion and the first silencing chamber through the internal space of the second tubular portion,
The protrusion amount of the first tubular portion and the protrusion amount of the second tubular portion may be different.

  In the above configuration (9), the first passage may be, for example, one of the passage 28 and the passage 30 described later, and the second passage may be, for example, the other of the passage 28 and the passage 30. When the second passage is the passage 28, the second tubular portion may be, for example, a tubular portion 54 described below, and when the second passage is the passage 30, the second tubular portion may be, for example, It may be a cylindrical portion 56 described later.

(10) In some embodiments, in the pump described in (9) above,
The ceiling wall portion, the first tubular portion, and the second tubular portion may be integrally formed of the same material.

(11) A pump according to at least one embodiment of the present invention is
A pump unit for transferring a fluid,
A first silencing chamber provided on the downstream side of the pump section,
A passage that is provided on the downstream side of the pump section and that guides fluid to the first silencing chamber;
Equipped with
The passage is
A first passage portion,
A second passage portion that branches from the first position of the first passage portion and joins at a second position downstream of the first position in the first passage portion;
Including,
At least one of the following condition (a) and condition (b) is satisfied.
(A) The length of the first passage portion from the first position to the second position is different from the length of the second passage portion.
(B) The passage diameter of the portion from the first position to the second position in the first passage portion is different from the passage diameter of the second passage portion.

  In the above configuration (11), the first silencing chamber may be, for example, the silencing chamber 12 described later. The passage may be, for example, the passage 33 described below. The first passage portion may be, for example, a first passage portion 34 described later. The second passage portion may be, for example, the second passage portion 35 described later.

  According to at least one embodiment of the present invention, a pump capable of reducing pulsation noise is provided.

It is a schematic diagram which shows the schematic structure of the pump 2 which concerns on one Embodiment. It is a schematic diagram which shows the schematic structure of the pump 2 which concerns on one Embodiment. It is a schematic diagram which shows the schematic structure of the pump 2 which concerns on one Embodiment. It is a schematic diagram which shows the schematic structure of the pump 2 which concerns on one Embodiment. It is a schematic exploded perspective view showing pump 2 concerning one embodiment. FIG. 6 is a partially cutaway sectional view of the pump 2 shown in FIG. 5. FIG. 6 is a partially cutaway sectional view of the pump 2 shown in FIG. 5, showing a sectional view different from that in FIG. 6. 8 is a graph showing the relationship between pump noise frequency and sound pressure level when the passage length and passage diameter of the passage 24 and passage 26 in the pump 2 shown in FIGS. 5 to 7 are changed. FIG. 9 is a diagram showing a pump operating time until reaching a predetermined vacuum degree and a sound pressure level (overall value) of pump noise in the three cases described with reference to FIG. 8.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples. Absent.
For example, the expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" are strict. In addition to representing such an arrangement, it also represents a state in which the components are relatively displaced by a tolerance or an angle or a distance at which the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous" that indicate that they are in the same state are not limited to a state in which they are exactly equal to each other. It also represents the existing state.
For example, the representation of a shape such as a quadrangle or a cylinder does not only represent a shape such as a quadrangle or a cylinder in a geometrically strict sense, but also an uneven portion or a chamfer within a range in which the same effect can be obtained. The shape including parts and the like is also shown.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.

FIG. 1 is a schematic diagram showing a schematic configuration of a pump 2 according to an embodiment.
As shown in FIG. 1, the pump 2 includes a pump unit 4 for transferring gas, an intake passage 6 for guiding the gas to the pump unit 4, and an exhaust passage 8 for guiding the gas from the pump unit 4 to the outside. The pump unit 4 includes a motor 10 that applies a driving force for sucking and discharging gas.

  The exhaust flow path 8 includes a muffling chamber 12 provided on the downstream side of the pump unit 4, and a passage 14 and a passage 16 that connect the pump unit 4 and the muffling chamber 12, respectively. Each of the passages 14 and 16 has a circular passage cross-sectional shape. The passage 14 is provided on the downstream side of the pump unit 4, and guides the gas discharged from the pump unit 4 to the muffling chamber 12. The passage 16 is arranged in parallel to the passage 14 on the downstream side of the pump unit 4, and guides the gas discharged from the pump unit 4 to the muffling chamber 12. The gas that has passed through the muffling chamber 12 is discharged to the outside of the pump 2 through the exhaust port 9 that is open to the atmosphere.

  At least one of the passage length and the passage diameter is different between the passage 14 and the passage 16. In the illustrated exemplary embodiment, each of the passages 14 and 16 does not have a branch portion, the passage length of the passage 14 is different from the passage length of the passage 16, and the passage diameter of the passage 14 is equal to that of the passage 16. It is different from the passage diameter. In another embodiment, the passage 14 and the passage 16 may be different from each other only in the passage length or the passage diameter or only in the passage diameter.

  Generally, in sound propagation in a passage such as a pipe, the longer the passage length, the lower the sound frequency, and the larger the passage diameter, the lower the sound frequency. Further, compared with the case where two sounds having the same frequency are superposed with the same phase, the sound pressure level can be reduced due to the phase shift when the two sounds having different frequencies are superposed. ..

  Therefore, at least one of the passage lengths and the passage diameters of the two passages 14 and 16 arranged in parallel so as to guide the gas to the muffling chamber 12 is made different so that they are propagated to the muffling chamber 12 through the passage 14. The frequency of the exhaust noise of the pump unit 4 and the frequency of the exhaust noise of the pump unit 4 propagated to the muffling chamber 12 via the passage 16 can be made different. As a result, the pulsating sound of the pump unit 4 is effectively reduced by utilizing the interference of the exhaust noise in the muffling chamber 12 where the exhaust gas guided through the passage 14 and the exhaust gas guided through the passage 16 join together. can do. Further, in general, the silencing effect is improved by enlarging the silencing chamber. However, in the pump 2, the pulsating sound of the pump portion 4 can be effectively reduced without enlarging the silencing chamber, so that the silencing chamber 12 is prevented from being enlarged. can do.

  Next, modified examples of the pump 2 will be described with reference to FIGS. In some of the embodiments shown in FIGS. 2 to 4, the configuration of the exhaust passage 8 is different from that of the pump 2 shown in FIG. 1, and the configurations other than the exhaust passage 8 are the same. .. Below, the components other than the exhaust flow channel 8 are denoted by the same reference numerals and the description thereof is omitted, and the configuration of the exhaust flow channel 8 will be described.

  In the form shown in FIG. 2, the exhaust flow path 8 includes an upstream silencing chamber 18 and a downstream silencing chamber 20 that are respectively provided on the downstream side of the pump unit 4. The downstream silencing chamber 20 is provided downstream of the upstream silencing chamber 18. Further, the exhaust flow path 8 includes a passage 22, a passage 24, and a passage 26, which are provided on the downstream side of the pump unit 4, respectively. Each of the passage 22, the passage 24, and the passage 26 has a circular passage sectional shape. The passage 22 connects the pump unit 4 and the upstream silencing chamber 18, and is configured to guide the gas discharged from the pump unit 4 to the upstream silencing chamber 18. The passage 24 connects the upstream silencing chamber 18 and the downstream silencing chamber 20, and is configured to guide the gas that has passed through the upstream silencing chamber 18 to the downstream silencing chamber 20. The passage 26 is arranged in parallel to the passage 24 so as to connect the upstream silencing chamber 18 and the downstream silencing chamber 20 to guide the gas passing through the upstream silencing chamber 18 to the downstream silencing chamber 20. It is configured. The gas that has passed through the downstream silencing chamber 20 is discharged to the outside of the pump 2 through the exhaust port 9 that is open to the atmosphere.

  At least one of the passage length and the passage diameter is different between the passage 24 and the passage 26. In the illustrated exemplary embodiment, each of the passages 24 and 26 has no branch portion, the passage length of the passage 24 is different from the passage length of the passage 26, and the passage diameter of the passage 24 is equal to that of the passage 26. It is the same as the passage diameter. In another embodiment, the passage 24 and the passage 26 may be different from each other only in the passage length and the passage diameter, or in both the passage length and the passage diameter.

  In such a configuration, the two passages 24, 26 arranged in parallel so as to guide the gas to the downstream silencing chamber 20 are made different in at least one of the passage length and the passage diameter, so that the downstream side via the passage 24. The frequency of the exhaust noise of the pump unit 4 propagated to the muffling chamber 20 and the frequency of the exhaust noise of the pump unit 4 propagated to the downstream muffler chamber 20 via the passage 26 can be made different. As a result, the pulsating sound of the pump unit 4 is effectively reduced by the interference of the exhaust noise in the downstream silencing chamber 20 where the exhaust guided through the passage 24 and the exhaust guided through the passage 26 join together. be able to.

  In the form shown in FIG. 3, the exhaust flow path 8 includes an upstream silencing chamber 18 and a downstream silencing chamber 20 that are respectively provided on the downstream side of the pump unit 4. The downstream silencing chamber 20 is provided downstream of the upstream silencing chamber 18. In addition, the exhaust flow path 8 includes a passage 28, a passage 30, a passage 24, and a passage 26 that are respectively provided on the downstream side of the pump unit 4. Each of the passage 28, the passage 30, the passage 24, and the passage 26 has a circular passage sectional shape. The passage 28 connects the pump unit 4 and the upstream silencing chamber 18, and is configured to guide the gas discharged from the pump unit 4 to the upstream silencing chamber 18. The passage 30 is arranged in parallel with the passage 28 so as to connect the pump unit 4 and the upstream silencing chamber 18, and is configured to guide the gas discharged from the pump unit 4 to the upstream silencing chamber 18. There is. The configurations of the passage 24, the passage 26, and the exhaust port 9 are the same as those in the configuration shown in FIG.

  At least one of the passage length and the passage diameter is different between the passage 28 and the passage 30. In the illustrated exemplary embodiment, each of the passage 28 and the passage 30 does not have a branch portion, the passage length of the passage 28 is different from the passage length of the passage 30, and the passage diameter of the passage 28 is different from that of the passage 30. It is the same as the passage diameter. In another embodiment, the passage 28 and the passage 30 may be different from each other only in the passage length and the passage diameter, or in both the passage length and the passage diameter.

  In such a configuration, the two passages 28 and 30 arranged in parallel so as to guide the gas to the upstream silencing chamber 18 are made different in at least one of the passage length and the passage diameter, so that the upstream side is provided via the passage 28. It is possible to make the frequency of the exhaust noise of the pump unit 4 propagated to the muffling chamber 18 different from the frequency of the exhaust noise of the pump unit 4 propagated to the upstream muffler chamber 18 via the passage 30. As a result, the pulsating sound of the pump portion 4 is effectively reduced by the interference of the exhaust noise in the upstream silencing chamber 18 where the exhaust guided through the passage 28 and the exhaust guided through the passage 30 join together. be able to.

  Further, similarly to the embodiment shown in FIG. 2, the pump part 4 is caused by the interference of the exhaust noise in the downstream silencing chamber 20 where the exhaust guided through the passage 24 and the exhaust guided through the passage 26 join together. It is possible to effectively reduce the pulsating sound.

  In the form shown in FIG. 4, the exhaust flow path 8 includes a muffling chamber 12 provided on the downstream side of the pump unit 4, and a passage 33 connecting the pump unit 4 and the muffling chamber 12. The passage 33 is provided on the downstream side of the pump unit 4, and guides the gas discharged from the pump unit 4 to the muffling chamber 12.

  The passage 33 is a second passage portion that branches from the first passage portion 34 at a first position P1 of the first passage portion 34 and joins at a second position P2 of the first passage portion 34 downstream of the first position P1. 35 and.

Here, the first passage portion 34 and the second passage portion 35 are configured to satisfy at least one of the following condition (a) and condition (b).
(A) The passage length from the first position P1 to the second position P2 in the first passage portion 34 is different from the passage length of the second passage portion 35.
(B) The passage diameter of the portion of the first passage portion 34 from the first position P1 to the second position P2 is different from the passage diameter of the second passage portion 35.

  In the illustrated exemplary embodiment, the first passage portion 34 and the second passage portion 35 are configured to satisfy only the condition (a) of the conditions (a) and (b). In another embodiment, the first passage portion 34 and the second passage portion 35 may be configured to satisfy only the condition (b) of the condition (a) and the condition (b), or the condition (a ) And the condition (b) may be satisfied.

  In such a configuration, at the second position P2 where the first passage portion 34 and the second passage portion 35 merge, the frequency of the exhaust noise of the pump portion 4 propagated through the first passage portion 34 and the second passage. The frequency of the exhaust noise of the pump unit 4 propagated via the unit 35 can be made different. As a result, the pulsation noise of the pump unit 4 is effectively reduced by the interference of the exhaust noise accompanying the confluence of the exhaust gas guided through the first passage unit 34 and the exhaust gas guided through the second passage unit 35. can do.

Next, a specific configuration example of the pump 2 shown in FIG. 3 will be described with reference to FIGS.
FIG. 5 is a schematic exploded perspective view showing the pump 2 according to the embodiment. FIG. 6 is a partially cutaway sectional view of the pump 2 shown in FIG. FIG. 7 is a partially cutaway cross-sectional view of the pump 2 shown in FIG. 5, showing a cross section different from that in FIG. The illustrated exemplary pump 2 is a vane type electric vacuum pump for making a negative pressure in a negative pressure chamber of a brake booster (master back) in a vehicle such as an automobile. Below, "upper" and "lower" mean "upper" and "lower" when the pump 2 is installed in the vehicle.

  As shown in FIGS. 5 and 6, the pump 2 includes a movable portion 7 for transferring gas and a pump casing 3 that houses the movable portion 7. The pump casing 3 includes a pump chamber 5 in which the movable portion 7 is arranged, an intake passage 6 for introducing gas into the pump chamber 5, and an exhaust passage 8 for introducing gas from the pump chamber 5 to the outside. Including. The movable part 7 is configured to be driven by a motor 10 as a drive device to suck gas into the pump chamber 5 and discharge gas from the pump chamber 5. The movable part 7 and the pump chamber 5 constitute the above-mentioned pump part 4.

  As shown in FIG. 5, the movable portion 7 includes a rotor 38 having a plurality of slits 36 formed on the outer peripheral surface 37 thereof, and a plurality of vanes 40 arranged at the plurality of slits 36. A later-described pump casing body 44 of the pump casing 3 includes a cam surface 42 that faces the outer peripheral surface 37 of the rotor 38.

  In the vane-type pump 2, the rotor 38 connected to the shaft (not shown) of the motor 10 is rotated by the motor 10, so that the vanes 40 are moved radially outward of the rotor 38 by the centrifugal force along the slits 36 of the rotor 38. The vane 40 slides on the cam surface 42 as the tip portion 13 of the vane 40 moves. As a result, the gas between the adjacent vanes 40 is transferred along with the movement of the vanes 40, and the gas is sucked into the pump chamber 5 and discharged from the pump chamber 5.

  As shown in FIGS. 5 and 6, the pump casing 3 includes a pump casing main body 44 that accommodates the movable portion 7, and a pump cover 46 that covers one side of the movable portion 7 (the upper side of the rotor 38 in the illustrated embodiment). A top cover 48 that covers the upper side of the pump cover 46 and a bottom cover 50 that is provided between the pump casing body 44 and the motor 10 and that covers the lower side of the pump casing body 44 are included. The pump cover 46 has an intake port (not shown) for allowing gas to flow from the intake flow path 6 into the pump chamber 5. 5 and 6, the top cover 48 side is the upper side and the motor 10 side is the lower side in the axial direction of the rotor 38. In the illustrated exemplary vacuum pump 2, the motor 10, the bottom cover 50, the pump casing body 44, the rotor 38, the pump cover 46, and the top cover 48 are arranged in this order from the lower side in the axial direction.

  As shown in FIG. 6, the exhaust flow path 8 includes an upstream silencing chamber 18 as an expansion chamber and a downstream silencing chamber 20 as an expansion chamber that are respectively provided on the downstream side of the pump unit 4. The upstream silencing chamber 18 is located below the pump unit 4, is formed between the pump casing main body 44 and the bottom cover 50, and functions as an extended sound absorber. The downstream silencing chamber 20 is located above the pump section 4 and the upstream silencing chamber 18, is formed between the pump cover 46 and the top cover 48 on the downstream side of the upstream silencing chamber 18, and is an expansion type sound absorber. Function as.

  Further, as shown in FIG. 6 or 7, the exhaust flow passage 8 includes a passage 24, a passage 26, a passage 28, and a passage 30, which are provided on the downstream side of the pump unit 4, respectively. The flow passage cross section of each of the passages 24, 26, 28, 30 is formed in a circular shape.

  As shown in FIG. 6, each of the passage 28 and the passage 30 is configured to connect the pump portion 4 and the upstream silencing chamber 18 and guide the gas discharged from the pump chamber 5 to the upstream silencing chamber 18. ing. The passage 28 and the passage 30 are arranged in parallel at different positions in the circumferential direction of the rotor 38.

  At least one of the passage length and the passage diameter is different between the passage 28 and the passage 30. In the illustrated exemplary embodiment, the passage length A1 of the passage 28 is different from the passage length B1 of the passage 30, and the passage diameter C1 of the passage 28 is the same as the passage diameter D1 of the passage 30.

  The upper surface of the ceiling wall portion 52 of the upstream silencing chamber 18 forms the bottom surface of the pump chamber 5, and the lower surface of the ceiling wall portion 52 is provided with a tubular portion 54 protruding downward. The passage 28 is formed as a through hole that vertically penetrates the ceiling wall portion 52, and connects the pump chamber 5 and the upstream silencing chamber 18 via the internal space of the tubular portion 54.

  Further, a cylindrical portion 56 protruding downward is provided on the lower surface of the ceiling wall portion 52 of the upstream silencing chamber 18. The passage 30 is formed as a through hole that vertically penetrates the ceiling wall portion 52, and connects the pump chamber 5 and the upstream silencing chamber 18 via the internal space of the tubular portion 56. The downward projection amount E1 of the tubular portion 54 and the downward projection amount F1 of the tubular portion 56 are different. The ceiling wall portion 52, the tubular portion 54, and the tubular portion 56 are integrally formed of the same material, and in the illustrated form, the pump casing body 44, the tubular portion 54, and the tubular portion 54 that configure the ceiling wall portion 52 The part 56 and the part 56 are made of the same material as an inseparable part.

  As shown in FIG. 7, each of the passages 24 and 26 connects the upstream silencing chamber 18 and the downstream silencing chamber 20 so that the gas passing through the upstream silencing chamber 18 is guided to the downstream silencing chamber 20. Is configured. The passage 24 and the passage 26 are arranged in parallel at different positions in the circumferential direction of the rotor 38.

  At least one of the passage length and the passage diameter is different between the passage 24 and the passage 26. In the illustrated exemplary embodiment, the passage length A2 of the passage 24 is different from the passage length B2 of the passage 26, and the passage diameter C2 of the passage 24 is the same as the passage diameter D2 of the passage 26.

  The ceiling wall portion 58 is provided with a tubular portion 60 that projects downward, and the passage 24 connects the upstream silencing chamber 18 and the downstream silencing chamber 20 via the internal space of the tubular portion 60. Communicate.

  Further, the ceiling wall portion 58 is provided with a tubular portion 62 projecting downward, and the passage 26 connects the upstream silencing chamber 18 and the downstream silencing chamber 20 to the inner space of the tubular portion 62. Communicate with each other. The downward projection amount E2 of the tubular portion 60 and the downward projection amount F2 of the tubular portion 62 are different. The ceiling wall portion 58, the tubular portion 60, and the tubular portion 62 are integrally formed of the same material, and in the illustrated embodiment, the pump casing body 44, the tubular portion 60, and the tubular portion that configure the ceiling wall portion 58. The shape portion 62 is made of the same material as one component that cannot be separated.

  In the configuration described above, as shown in FIG. 6, the gas discharged from the pump chamber 5 flows into the upstream silencing chamber 18 through the passage 28 and the passage 30. As shown in FIG. 7, the gas that has flowed into the upstream silencing chamber 18 flows into the downstream silencing chamber 20 through the passages 24 and 26, passes through the downstream silencing chamber 20 and the exhaust port 9 (see FIG. 5). ) Is discharged to the outside of the pump 2.

  In the above configuration, the passage amount of the passage 28 is made different by changing the protrusion amount E1 of the tubular portion 54 (the length of the tubular portion 54) and the protrusion amount F1 of the tubular portion 56 (the length of the tubular portion 56). The length A1 is different from the passage length B1 of the passage 30. Thus, with a simple configuration, the interference of the exhaust noise in the upstream silencing chamber 18 where the exhaust gas guided through the passage 28 and the exhaust gas guided through the passage 30 join together is utilized. The pulsating sound can be effectively reduced. That is, it is possible to effectively suppress the pulsating sound of the pump unit 4 while suppressing an increase in size of the upstream silencing chamber 18 and the downstream silencing chamber 20. Further, it can be suitably used in terms of quietness for an electric vehicle without engine noise.

  Further, since the ceiling wall portion 52, the tubular portion 54, and the tubular portion 56 of the upstream silencing chamber 18 are integrally formed of the same material, the pulsating sound of the pump portion 4 is suppressed while suppressing an increase in the number of parts. Can be effectively reduced, and the cost of the pump 2 can be reduced.

  Further, by making the protrusion amount E2 of the tubular portion 60 (the length of the tubular portion 60) and the protrusion amount F2 of the tubular portion 62 (the length of the tubular portion 62) different, the passage length A2 of the passage 24. And the passage length B2 of the passage 24 is made different. Accordingly, with a simple structure, the interference of the exhaust noise in the downstream silencing chamber 20 where the exhaust gas guided through the passage 24 and the exhaust gas guided through the passage 26 join together is utilized to pump the pump unit 4. The pulsating sound can be effectively reduced. That is, it is possible to effectively suppress the pulsating sound of the pump unit 4 while suppressing an increase in size of the upstream silencing chamber 18 and the downstream silencing chamber 20. Further, it can be suitably used in terms of quietness for an electric vehicle without engine noise.

  Further, since the ceiling wall portion 58, the tubular portion 60, and the tubular portion 62 of the upstream silencing chamber 18 are integrally formed of the same material, the pulsating noise of the pump portion 4 is suppressed while suppressing an increase in the number of parts. Can be effectively reduced, and the cost of the pump 2 can be reduced.

  FIG. 8 is a graph showing the relationship between the frequency of the pump noise and the sound pressure level when the passage length and the passage diameter of the passage 24 and the passage 26 in the pump 2 shown in FIGS. 5 to 7 are changed. In the graph shown in FIG. 8, the solid line indicates that the passage 24 has a large passage diameter, the passage 24 has a long passage length, the passage 26 has a passage diameter equal to the passage 24, and the passage 26 has a passage length of the passage 24. The case where it is equal to the passage length is shown. The alternate long and short dash line shows the case where the passage 24 has a small passage diameter, the passage 24 has a long passage length, the passage 26 has a passage diameter equal to the passage 24, and the passage 26 has a passage length shorter than the passage 24. ing. The broken line shows the case where the passage diameter of the passage 24 is small, the passage length of the passage 24 is long, the passage diameter of the passage 26 is equal to the passage diameter of the passage 24, and the passage length of the passage 26 is equal to the passage length of the passage 24. There is.

  As shown in FIG. 8, when the passage diameters of both the passage 24 and the passage 26 are small and the passage length of the passage 26 is shorter than the passage length of the passage 24 (in the case of the one-dot chain line graph), the passage 24 and the passage 26 are separated from each other. The sound pressure level of the frequency of the pulsating sound of the pump 2 can be effectively reduced as compared with the case where both passage diameters are large and the passage length is long (the case of the solid line graph).

  FIG. 9 is a diagram showing a pump operating time until reaching a predetermined vacuum degree and a sound pressure level (overall value) of pump noise in the three cases described with reference to FIG. Here, the shorter the pump operating time, the faster the exhaust speed.

  9, a white triangle corresponds to the case shown by the solid line in FIG. 8, a black triangle corresponds to the case shown by the alternate long and short dash line in FIG. 8, and a white circle corresponds to the case shown by the broken line in FIG.

  As shown in FIG. 9, when both the passage 24 and the passage 26 have a large passage diameter and a long passage length (white triangles), the passage 24 and the passage 26 both have a small passage diameter and a long passage length. In (white circle), the sound pressure level can be reduced, but the pump operating time becomes longer.

  On the other hand, when both the passages 24 and 26 have a small passage diameter and the passage 26 has a passage length shorter than the passage 24 (black triangle), the passages 24 and 26 have a large passage diameter. The sound pressure level can be effectively reduced as compared with the case where the passage length is long (white triangle), and the pump operating time can be effectively shortened as compared with the case where the above-mentioned white circle is provided. In this way, by making the passage diameter of the passage 24 different from the passage diameter of the passage 26, it is possible to realize the high-performance pump 2 that achieves both exhaust noise with a low sound pressure level and good pump efficiency.

  The present invention is not limited to the above-described embodiment, and includes a modified form of the above-described embodiment and a combination of these forms as appropriate.

  For example, although the vane type vacuum pump has been described as an example of the pump in the above-described embodiment, the pump may be, for example, a piston type pump or a diaphragm type pump. When the pump is a vane type pump, it may be a balanced vane pump or a non-balanced vane pump. Further, the pump is not limited to a vacuum pump, and may be a compressor of an air conditioner or the like, and the fluid transferred by the pump is not limited to gas but may be liquid.

  Further, the shape, length, and number of passages connected to the muffling chamber are not particularly limited, and by adjusting these, it is possible to obtain a muffling effect while suppressing deterioration of exhaust performance.

  Further, the cross-sectional shapes of the inner peripheral surface and the outer peripheral surface of the tubular portions 54, 56, 60, 62 may not be circular. Further, the outer peripheral surfaces of the tubular portions 54, 56, 60, 62 may be connected to the side wall of the upstream silencing chamber 18, as shown in FIG. 7, for example.

  Further, in the embodiment shown in FIG. 6, the projection length E1 of the tubular portion 54 and the projection amount F1 of the tubular portion 56 are made different so that the passage length A1 of the passage 28 and the passage length B1 of the passage 30 are made different. However, one of the protrusion amount E1 and the protrusion amount F1 may be 0. That is, only one of the tubular portion 54 and the tubular portion 56 may be provided on the ceiling wall portion 52.

  Further, in the embodiment shown in FIG. 7, the projection length E2 of the tubular portion 60 and the projection amount F2 of the tubular portion 62 are made different so that the passage length A2 of the passage 24 and the passage length B2 of the passage 26 are made different. However, one of the protrusion amount E2 and the protrusion amount F2 may be 0. That is, the ceiling wall portion 58 may be provided with only one of the tubular portion 60 and the tubular portion 62.

  Further, the protruding amounts E3 and F3 of the cylindrical portions 66 and 68 protruding upward from the upper surface of the bottom wall portion 64 of the downstream silencing chamber 20 (the upper surface of the ceiling wall portion 58 of the upstream silencing chamber 18) are different from each other. By doing so, the passage length A2 of the passage 24 and the passage length B2 of the passage 26 may be different.

  Further, the muffling chamber 12 described above may be located above the pump chamber 5. In this case, the tubular parts 54 and 56 project upward.

  Further, the upstream silencing chamber 18 may be located above the pump chamber 5, and the downstream silencing chamber 20 may be located below the pump chamber 5 and the upstream silencing chamber 18. In this case, the tubular portions 54, 56, 60, 62 project upward. Further, in this case, the passage lengths may be made different by making the protruding amount of the tubular portion protruding downward from the lower surface of the ceiling wall portion of the downstream silencing chamber 20 different.

2 pump 4 pump part 12 muffling chamber 14, 16, 24, 26, 28, 30, 33 passage 18 upstream muffling chamber 20 downstream muffling chamber 34 first passage part 35 second passage part 52, 58 ceiling wall part 54, 56, 60, 62 Cylindrical part

Claims (11)

A pump unit for transferring a fluid,
A first silencing chamber provided on the downstream side of the pump section,
A first passage that is provided on the downstream side of the pump portion and guides the fluid to the first silencing chamber;
A second passage that is arranged in parallel to the first passage on the downstream side of the pump portion and guides the fluid to the first silencing chamber;
Equipped with
A pump in which at least one of a passage length and a passage diameter is different between the first passage and the second passage. Further comprising a second silencing chamber provided on the downstream side of the pump section,
The pump according to claim 1, wherein each of the first passage and the second passage connects the first silencing chamber and the second silencing chamber. The second silencing chamber is provided above the first silencing chamber,
A first cylindrical portion that protrudes downward is provided on the ceiling wall portion of the first silencing chamber,
The pump according to claim 2, wherein the first passage connects the first silencing chamber and the second silencing chamber through an internal space of the first tubular portion. A second tubular portion that protrudes downward is formed on the ceiling wall portion,
The second passage connects the first silencing chamber and the second silencing chamber via an internal space of the second tubular portion,
The pump according to claim 3, wherein the protrusion amount of the first tubular portion is different from the protrusion amount of the second tubular portion.   The pump according to claim 4, wherein the ceiling wall portion, the first tubular portion, and the second tubular portion are integrally formed of the same material. A third passage connecting the pump portion and the second silencing chamber, and a fourth passage arranged in parallel with the third passage and connecting the pump portion and the second silencing chamber. Prepare,
The pump according to any one of claims 2 to 5, wherein at least one of a passage length and a passage diameter is different between the third passage and the fourth passage.   The pump according to claim 1, wherein each of the first passage and the second passage connects the pump unit and the first silencing chamber. The first silencing chamber is provided below the pump section,
A first cylindrical portion that protrudes downward is formed on the ceiling wall portion of the first silencing chamber,
The pump according to claim 7, wherein the first passage communicates the pump unit with the first silencing chamber via an internal space of the first tubular portion. A second tubular portion that protrudes downward is formed on the ceiling wall portion,
The second passage communicates the pump unit with the first silencing chamber through an internal space of the second tubular portion,
The pump according to claim 8, wherein the protrusion amount of the first tubular portion and the protrusion amount of the second tubular portion are different.   The pump according to claim 9, wherein the ceiling wall portion, the first tubular portion, and the second tubular portion are integrally formed of the same material. A pump unit for transferring a fluid,
A first silencing chamber provided on the downstream side of the pump section,
A passage that is provided on the downstream side of the pump portion and that guides the fluid to the first silencing chamber;
Equipped with
The passage is
A first passage portion,
A second passage portion that branches from a first position of the first passage portion and joins at a second position downstream of the first position in the first passage portion;
Including,
A pump satisfying at least one of the following condition (a) and condition (b).
(A) The length of the first passage portion from the first position to the second position is different from the length of the second passage portion.
(B) The passage diameter of the portion from the first position to the second position in the first passage portion is different from the passage diameter of the second passage portion.

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