JP2005155610A - Negative pressure supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative pressure supply device for supplying negative pressure to an air-pressure servo unit for an automobile brake with a higher degree of vacuum while reducing the load of a vacuum pump. <P>SOLUTION: A coil 8 of a vacuum pump unit 2 is energized and excited to give reciprocation to a piston on which a magnet 10 is mounted in a cylinder 5 whereby an outlet passage 31 of a diffuser 27 of an ejector 25 is vacuumed up to supply discharge air to the inlet of a nozzle 26. Thus, a high speed jet flow occurs in a throat portion 28 of the nozzle 26 to generate negative pressure in a suction port 29 of the ejector 25 with a higher degree of vacuum than the vacuum negative pressure in the vacuum pump unit 2 and supply the negative pressure from a negative pressure supply port 32. The ejector 25 supplies the negative pressure with a higher degree of vacuum while reducing the load of the vacuum pump unit 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a negative pressure supply device for supplying negative pressure to a pneumatic booster or the like of an automobile braking device.

  In general, a braking device for an automobile is provided with a pneumatic booster to increase the braking force. This atmospheric pressure booster uses the intake negative pressure of the engine as a negative pressure source, introduces the intake negative pressure into the constant pressure chamber (negative pressure chamber), and supplies it to the power piston by the differential pressure from the atmospheric pressure. Thrust is generated to assist the operating force of the braking device.

In recent years, in automobile engines, pumping loss has been reduced due to demands for low fuel consumption. For this reason, intake pipe negative pressure tends to decrease, and there is a shortage of negative pressure supplied to the pneumatic booster. It has become a problem.
On the other hand, as shown in Patent Document 1, for example, by using an electric rotary vacuum pump as a negative pressure source of the pneumatic booster, the pneumatic booster is used regardless of the operating state of the engine. It is possible to supply a sufficient negative pressure.
JP 2002-195178 A

  However, the vacuum pump described in the above publication has the following problems. Although the vane pump is used as the vacuum pump, the vane pump has a complicated structure, a high manufacturing cost, and is difficult to reduce in size. Although it is conceivable to use a reciprocating piston type vacuum pump with a simple structure, the reciprocating piston type vacuum pump has a high degree of vacuum required for a pneumatic booster because atmospheric pressure acts as the back pressure of the piston. If it is going to obtain, load fluctuation will become large and smooth operation will become difficult.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a negative pressure supply device that can supply a high vacuum with a simple structure.

In order to solve the above-described problem, a negative pressure supply device according to the invention of claim 1 includes an ejector in which a diffuser is disposed on the downstream side of a nozzle and a suction port is opened therebetween, and the diffuser A suction port of a vacuum pump is connected to the outlet of the vacuum pump, and negative pressure is supplied from the suction port of the ejector.
A negative pressure supply device according to a second aspect of the present invention is the structure of the first aspect, wherein the suction port and the suction port of the vacuum pump are each connected to a negative pressure supply port via a check valve, and the suction port Of the suction ports, the negative pressure having a higher degree of vacuum is supplied from the negative pressure supply port.
A negative pressure supply device according to a third aspect of the invention is characterized in that, in the configuration of the first or second aspect, the vacuum pump is a reciprocating pump having a piston driven by a linear actuator.
According to a fourth aspect of the present invention, there is provided the negative pressure supply means according to any one of the first to third aspects, wherein the discharge side of the vacuum pump is connected to an engine intake pipe.
According to a fifth aspect of the present invention, in the negative pressure supply device according to any one of the first to third aspects, the suction port of the second ejector is connected to the discharge side of the vacuum pump, and the inlet of the second ejector and The outlet is connected to an engine intake pipe, and negative pressure is generated at the suction port of the second ejector by engine intake negative pressure.
According to a sixth aspect of the present invention, there is provided the negative pressure supply device according to the fifth aspect, wherein a first check valve is provided between the discharge side of the vacuum pump and the suction port of the second ejector, and the vacuum pump Of the suction port of the second ejector or the negative pressure of the engine intake pipe is supplied to the discharge side of the vacuum pump. It is characterized by supplying.
According to a seventh aspect of the present invention, there is provided the negative pressure supply device according to any one of the fourth to sixth aspects, further comprising a third check valve that opens the discharge side of the vacuum pump to the atmosphere. The negative pressure supply device according to any one of claims 4 to 6.

According to the negative pressure supply device of the first aspect of the present invention, air flows from the nozzle of the ejector to the diffuser by suction of the vacuum pump, thereby generating a high-speed jet at the throat portion of the nozzle, and a vacuum at the suction port. A negative pressure with a vacuum level higher than the suction negative pressure of the pump is generated, and this high vacuum level negative pressure can be supplied.
According to the negative pressure supply device of the second aspect of the invention, the negative pressure of the higher vacuum degree of the suction port of the ejector or the suction port of the vacuum pump can be supplied by the check valve. Negative pressure can be supplied.
According to the negative pressure supply device of the third aspect of the invention, the structure of the vacuum pump can be simplified, and downsizing and manufacturing cost can be reduced.
According to the negative pressure supply device of the fourth aspect of the invention, the engine intake negative pressure can be supplied to the discharge side of the vacuum pump, and the burden on the vacuum pump can be reduced.
According to the negative pressure supply device of the fifth aspect of the invention, the second ejector can supply a negative pressure having a higher degree of vacuum than the engine intake negative pressure to the discharge side of the vacuum pump.
According to the negative pressure supply device of the sixth aspect of the present invention, the first and second check valves supply the negative pressure of the suction port of the second ejector or the negative pressure of the engine intake pipe that can be supplied. Therefore, the negative pressure can be efficiently supplied to the discharge side of the vacuum pump.
According to the negative pressure supply device of the seventh aspect of the invention, when the discharge side of the vacuum pump becomes positive pressure, the third check valve opens and the pressure is released to the atmosphere. It is possible to prevent the discharge side of the vacuum pump from becoming a positive pressure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. As shown in FIGS. 1 to 3, the negative pressure supply device 1 according to this embodiment has a configuration in which a vacuum pump unit 2 (vacuum pump) and an ejector unit 3 are coupled via a manifold unit 4. .

  The vacuum pump unit 2 is a reciprocating pump having a piston driven by a movable magnet type linear motor, and a piston 6 also serving as a mover is slidably fitted in a cylinder 5 also serving as a stator. . The piston 6 is guided by a rod 7 fixed along the center of the cylinder 5. A plurality of coils 8 are attached to the outer peripheral portion of the cylinder 5, and a plurality of magnets 10 are attached to the outer peripheral portion of the piston 6 together with a magnetic path member 9. By sequentially exciting, the piston 6 can be reciprocated in the cylinder 5. An annular seal 6 </ b> A made of a synthetic resin having good slidability that defines the inside of the cylinder 5 is provided at the center of the magnet 10.

  The inside of the cylinder 5 is defined by the piston 6 into two chambers 5A and 5B. One chamber 5A is communicated with the first suction port 12 (suction port) by the passage 11, and is One discharge port 14 is in communication. The passage 11 is provided with a check valve 15 that allows only air to flow from the first suction port 12 side to the chamber 5A side, and the passage 13 has a passage from the chamber 5A side to the first discharge port 14 side. A check valve 16 that allows only air flow is provided. The other chamber 5 </ b> B communicates with the second suction port 18 (suction port) through the passage 17 and communicates with the second discharge port 20 through the passage 19. The passage 17 is provided with a check valve 22 that allows only air flow from the second suction port 18 side to the chamber 5B side, and the passage 19 has a passage from the chamber 5B side to the second discharge port 20 side. A check valve 21 that allows only air flow is provided. The first and second suction ports 12 and 18 and the first and second discharge ports 14 and 20 are disposed to face the manifold unit 4.

  An ejector 25 is formed in the ejector unit 3. As shown in FIG. 2, the ejector 25 is configured such that a diffuser 27 is disposed on the downstream side of the nozzle 26 to form a Laval nozzle, and a suction port 29 is opened downstream of the throat portion 28 of the nozzle 26. When gas flows from the inlet 30 to the outlet passage 31 (exit) of the diffuser 27, a high-speed jet that reaches the sonic speed is generated in the throat portion 28. By this high-speed jet, the gas in the suction port 29 is sucked, and a negative pressure having a higher degree of vacuum than the negative pressure in the outlet passage 31 of the diffuser 27 can be obtained from the suction port 29. The ejector 25 has a two-dimensional shape in which a concave portion is provided on the joint surface of the ejector unit 3 with the manifold unit 4 to form a flat plate, thereby easily processing the ejector 25 having a complicated shape with high accuracy. It becomes possible to do.

  The ejector unit 3 is provided with a negative pressure supply port 32 for connection to a negative pressure operating device (not shown) such as a pneumatic booster. The negative pressure supply port 32 is non-returned by a passage 33. The valve is connected to the suction port 29 and the outlet passage 31 via valves 34 and 35, respectively. The check valve 34 allows only air flow from the negative pressure supply port 32 side to the suction port 29 side, and the check valve 35 only allows air flow from the negative pressure supply port 32 side to the outlet passage 31 side. Is allowed.

  The manifold unit 4 is provided with a suction passage 36 that communicates the first and second suction ports 12 and 18 of the vacuum pump unit 2 with the outlet passage 31 of the ejector unit 3. In addition, the manifold unit 4 is provided with a discharge passage 37 that allows the first and second discharge ports 14 and 20 of the vacuum pump unit 2 to communicate with the inlet 30 of the ejector unit 3. The discharge passage 37 is opened to the atmosphere via a check valve 38, and the check valve 38 allows only air flow from the discharge passage 37 side to the atmosphere side.

Next, the operation of the present embodiment configured as described above will be described.
When the coil 8 of the vacuum pump unit 2 is excited by energization, the piston 6 in the cylinder 5 reciprocates due to the action of the magnetic field, and the first and second suction ports 12, 18 through the check valves 15, 22. The air is sucked in from the first and second discharge ports 14 and 20 through the check valves 16 and 21. Then, air in the outlet passage 31 of the ejector 25 is sucked through the suction passage 36 of the manifold unit 4, and discharge air is supplied to the inlet 30 of the ejector 25 through the discharge passage 37. At this time, the check valve 38 prevents the discharge passage 37 from becoming a positive pressure.

  As a result, an air flow from the inlet 30 of the nozzle 26 to the outlet passage 31 of the diffuser 27 occurs, and the action of the nozzle 26 and the diffuser 27 forming the Laval nozzle causes a high-speed jet flow reaching the sonic speed to the throat portion 28, and suction. A negative pressure with a degree of vacuum higher than the suction negative pressure of the pump unit 2 is generated at the port 29. This high vacuum negative pressure is supplied from a negative pressure supply port 32 to a negative pressure operating device such as a pneumatic booster via a check valve 34.

  In this way, the negative pressure generated by the vacuum pump unit 2 can be increased by the ejector 25, which is necessary for a negative pressure operating device such as a pneumatic booster while reducing the load on the vacuum pump unit 2. A negative pressure with a high degree of vacuum can be supplied. At this time, a negative pressure of about −500 mmHg can be supplied by generating a negative pressure of about −250 mmHg to −300 mmHg by the vacuum pump unit 2. As a result, since the load on the vacuum pump unit 2 is reduced, the vacuum pump can be reduced in size, and load fluctuations due to suction and discharge are reduced, so that the vacuum pump can be operated smoothly.

  Furthermore, for example, when the negative pressure supply device 1 is used for a pneumatic booster for a brake of an automobile, the negative pressure of the pneumatic booster is extremely reduced due to continuous operation of the brake. The check valve 35 is opened, and the first and second suction ports 12 and 18 of the vacuum pump unit 2 directly suck in the air of the negative pressure supply port 32 to increase the suction flow rate, thereby increasing the air pressure type. The negative pressure of the force device can be quickly recovered.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In the following description, the same reference numerals are assigned to the corresponding parts in the first embodiment, and only different parts will be described in detail.

  As shown in FIGS. 4 and 5, in the negative pressure supply device 39 according to the present embodiment, the manifold unit 4 of the first embodiment is omitted, and the vacuum pump unit 2 and the ejector unit 3 are directly coupled. Yes. The first and second suction ports 11 and 18 of the vacuum pump unit 2 are communicated with each other via a passage 40 in the hollow rod 7 and directly communicated with the outlet passage 31 of the ejector unit 3. The first and second discharge ports 14 and 20 are directly opened to the atmosphere, and the inlet 30 of the ejector unit 3 communicates with the first discharge port 14 and is opened to the atmosphere.

  In the vacuum pump unit 2 according to the present embodiment, the piston 6 has a larger diameter and a shorter stroke than the first embodiment, so that only two coils 8 are provided. Further, the check valve 15 and 22 on the suction side and the check valve 16 and 21 on the discharge side are arranged along the diameter direction of the piston 6 by utilizing a space generated by increasing the diameter of the piston 6. Thereby, the components of the check valves 15 and 22 and the check valves 16 and 21 are made common.

With this configuration, as in the first embodiment, the negative pressure generated by the vacuum pump unit 2 can be increased by the ejector 25, and the load on the vacuum pump unit 2 can be reduced while the pressure type is doubled. A negative pressure having a high degree of vacuum required for a negative pressure operating device such as a force device can be supplied. In the present embodiment, atmospheric pressure air is supplied to the inlet 30 of the ejector 25.
Further, compared to the first embodiment, the manifold unit 4 is omitted, the check valves 15, 16, 21, and 22 are shared, and only two coils 8 are used, thereby simplifying the structure. Manufacturing cost can be reduced.

  In the first and second embodiments, a reciprocating piston type pump is used as the vacuum pump. However, other types of pumps such as an axial piston pump, a vane pump, a scroll pump, etc. may be used. Is possible. As a pump drive source, in addition to a movable magnet type linear motor, other types of linear motors such as a linear SRM (switched reluctance motor) that does not require a magnet can be used, and a rotary pump is used. In this case, a rotary motor can be used.

Next, a third embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected and demonstrated with respect to the said 1st Embodiment.
As shown in FIG. 6, in the negative pressure supply device 41 according to the present embodiment, the suction port 29 of the ejector 25 has a negative pressure such as a pneumatic booster via a check valve 34, as in the first embodiment. Connected to the operating device, the outlet passage 31 is connected to the suction port of the vacuum pump unit 2 and connected to the negative pressure operating device via the check valve 35, and the inlet 30 is the discharge port of the vacuum pump unit 2. It is connected to the. The inlet 30 of the ejector 25 and the discharge port of the vacuum pump unit 2 are connected to the engine intake pipe (downstream of the throttle valve).

  The drive circuit 42 that drives the vacuum pump unit 2 is connected to a negative pressure switch 43 that detects a negative pressure of a negative pressure operating device (such as a negative pressure chamber of a pneumatic booster). When the degree of vacuum drops to a predetermined level, the negative pressure switch 43 is turned on and the vacuum pump unit 2 is driven by the drive circuit 42.

Next, the operation of the present embodiment configured as described above will be described.
While the vacuum pump unit 2 is stopped, engine intake negative pressure is directly supplied from the engine intake pipe to the negative pressure operating device via the vacuum pump unit 2, the ejector 25 and the check valves 34 and 35.

  When the vacuum pump unit 2 is operated, an air flow from the inlet 30 to the outlet passage 31 of the ejector 25 is generated due to the differential pressure between the suction port and the discharge port of the vacuum pump unit 2, thereby causing the suction port 29 of the ejector 25 to flow. A negative pressure having a degree of vacuum higher than the suction negative pressure of the vacuum pump unit 2 is generated, and this negative pressure is supplied to the negative pressure operating device via the check valve 34. At this time, since the discharge side of the vacuum pump unit 2 is sucked by the engine intake negative pressure, the degree of vacuum of the negative pressure generated at the suction port 29 of the ejector 25 can be increased and the suction flow rate can be increased. The burden of 2 can be reduced.

  The negative pressure switch 43 monitors the degree of vacuum of the negative pressure operating device. If the degree of vacuum is sufficiently high, the negative pressure switch 43 is turned off, the vacuum pump unit 2 is stopped, and the engine intake negative pressure is negative. Supplied directly to the actuator. When the negative pressure of the negative pressure operating device decreases to a predetermined level, the negative pressure switch 43 is turned on, the vacuum pump unit 2 is operated, and a high negative vacuum pressure is supplied from the suction port 29 of the ejector 25, The vacuum degree of the negative pressure operating device can be quickly recovered.

  In this way, the suction side of the vacuum pump unit 2 is sucked by the engine intake negative pressure, and the operation of the vacuum pump unit 2 is turned on and off as necessary, thereby reducing the power consumption of the vacuum pump unit 2. Thus, a negative pressure with a high degree of vacuum can be supplied, and the vacuum pump unit 2 can be downsized. Even when the vacuum pump unit 2 is broken or the throat portion 28 of the ejector 25 is clogged, the engine intake negative pressure is directly supplied to the negative pressure operating device, so that the operating state of the negative pressure operating device is maintained. be able to.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same part with respect to the said 3rd Embodiment, and only a different part is demonstrated in detail.

  As shown in FIG. 7, in the negative pressure supply device 44 according to the present embodiment, the discharge side of the vacuum pump unit 2 connected to the inlet 30 of the ejector 25 is connected via check valves 45 and 46 and a second ejector 47. Connected to the engine intake pipe 48. Similar to the ejector 25 described above, the second ejector 47 has a structure in which a nozzle and a diffuser are combined. The diffuser inlet 49 is connected to the upstream side of the throttle valve 50 of the engine intake pipe 48, and the diffuser outlet 51 is connected to the second ejector 47. Connected to the downstream side of the throttle valve 50, the suction port 52 between the nozzle and the diffuser is connected to the discharge side of the vacuum pump unit 2 via a check valve 45 (first check valve). The outlet 51 of the second ejector 47 is connected to the discharge side of the vacuum pump unit 2 via a check valve 46 (second check valve). The check valves 45 and 46 allow only the flow from the discharge side of the vacuum pump unit 2 to the suction port 52 side and the outlet 51 (engine intake pipe 48) side of the second ejector 47, respectively.

  With this configuration, an air flow is generated from the inlet 49 to the outlet 51 of the second ejector 47 due to the differential pressure between the upstream side and the downstream side of the throttle valve 50 of the engine intake pipe 48, and thereby the suction port 52. The negative pressure of the vacuum higher than that of the engine intake pipe 48 generated in the above can be supplied to the discharge side of the vacuum pump unit 2, and the vacuum of the negative pressure supplied to the negative pressure operating device can be increased. As a result, the vacuum pump unit 2, the ejector 25, and the second ejector 47 can be reduced in size. When the vacuum degree of the negative pressure operating device is low, such as immediately after starting the vehicle, and the vacuum degree on the discharge side of the vacuum pump unit 2 is lower than the downstream side of the throttle valve 50 of the engine intake pipe 48, the check valve 46 opens, and the negative pressure downstream of the throttle valve 50 is supplied directly to the discharge side of the vacuum pump unit 2.

  In addition, when the vacuum pump unit 2 fails or the throat portion 28 of the ejector 25 is clogged, the ejector 25 does not function, but a vacuum higher than the engine intake negative pressure from the suction port 52 of the second ejector 47. The negative pressure can be supplied to the negative pressure operating device, and the operating state of the negative pressure operating device can be maintained.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same part with respect to the said 4th Embodiment, and only a different part is demonstrated in detail.

  As shown in FIG. 8, the negative pressure supply device 53 according to this embodiment is attached to an engine equipped with a supercharger such as a turbocharger, and is disposed upstream of the throttle valve 50 in the engine intake pipe 48. A supercharger 54 and an intercooler 55 are provided, and a check valve 56 (third check valve) is connected to the discharge side of the vacuum pump unit 2. The check valve 56 is for opening the discharge side of the vacuum pump unit 2 to the atmosphere, and allows only the flow from the discharge side of the vacuum pump unit 2 to the atmosphere side.

Next, the operation of the present embodiment configured as described above will be described.
When the engine speed is high, all of the inside of the engine intake pipe 48 on the downstream side of the supercharger 54 (the upstream side and the downstream side of the intercooler 55 and the throttle valve 50) is positive pressure due to the supercharging pressure of the supercharger 54. It may become. In such a case, the positive pressure is prevented from flowing into the discharge side of the vacuum pump unit 2 by the check valves 45 and 46, and the discharge side of the vacuum pump unit 2 is opened to the atmosphere by the check valve 56. Accordingly, it is possible to prevent the degree of vacuum of the negative pressure supplied to the negative pressure operating device from being excessively reduced when the discharge side of the vacuum pump unit 2 becomes atmospheric pressure or higher. Thereby, even in an engine provided with a supercharger, a stable negative pressure can be supplied to the negative pressure operating device.

  In addition, when the negative pressure supply device 41 of the third embodiment is mounted on an engine equipped with a supercharger, the discharge side of the vacuum pump unit 2 is set to the atmosphere as in the case of the fifth embodiment. By providing a check valve that opens, it is possible to prevent the discharge side of the vacuum pump unit 2 from becoming positive pressure due to the effect of supercharging, and it is possible to supply a stable negative pressure to the negative pressure operating device. Become.

It is a longitudinal cross-sectional view of the negative pressure supply apparatus which concerns on 1st Embodiment of this invention. It is a cross-sectional view by the AA line of the apparatus shown in FIG. It is a pneumatic circuit diagram which shows the structure of the apparatus shown in FIG. It is a longitudinal cross-sectional view of the negative pressure supply apparatus which concerns on 2nd Embodiment of this invention. It is a pneumatic circuit diagram which shows the structure of the apparatus shown in FIG. It is a pneumatic circuit figure showing the composition of the negative pressure supply device concerning a 3rd embodiment of the present invention. It is a pneumatic circuit figure showing the composition of the negative pressure supply device concerning a 4th embodiment of the present invention. It is a pneumatic circuit figure showing the composition of the negative pressure supply device concerning a 5th embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Negative pressure supply apparatus, 2 Vacuum pump unit (vacuum pump), 12 1st suction port (suction port), 18 2nd suction port (suction port), 25 Ejector, 26 Nozzle, 27 Diffuser, 29 Suction port, 31 Outlet Passage (exit), 34, 35 Check valve

Claims (7)

A diffuser is arranged on the downstream side of the nozzle, and there is an ejector with a suction port opened between them. A suction port of a vacuum pump is connected to the outlet of the diffuser, and negative pressure is supplied from the suction port of the ejector. A negative pressure supply device characterized by: The suction port and the suction port of the vacuum pump are respectively connected to a negative pressure supply port via a check valve, and the negative pressure of the higher vacuum degree of the suction port and the suction port is connected to the negative pressure supply port. The negative pressure supply device according to claim 1, wherein the negative pressure supply device is supplied from a negative pressure supply device. The negative pressure supply device according to claim 1, wherein the vacuum pump is a reciprocating pump having a piston driven by a linear actuator. 4. The negative pressure supply device according to claim 1, wherein a discharge side of the vacuum pump is connected to an engine intake pipe. The suction port of the second ejector is connected to the discharge side of the vacuum pump, the inlet and outlet of the second ejector are connected to the engine intake pipe, and negative pressure is applied to the suction port of the second ejector by the engine intake negative pressure. The negative pressure supply device according to any one of claims 1 to 3, wherein the negative pressure supply device is generated. A first check valve is provided between the discharge side of the vacuum pump and the suction port of the second ejector, and the discharge side of the vacuum pump is connected to the engine intake pipe via the second check valve. 6. The negative pressure supply device according to claim 5, wherein a negative pressure that can be supplied out of the suction port of the two ejectors or the negative pressure of the engine intake pipe is supplied to the discharge side of the vacuum pump. The negative pressure supply device according to claim 4, further comprising a third check valve that opens the discharge side of the vacuum pump to the atmosphere.

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