JP2007285126A - Negative pressure supply device for brake booster - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative pressure supply device for a brake booster capable of supplying negative pressure constantly in an intake pipe sufficient to operate the brake booster so that an air ejector is operated only when negative pressure in the intake pipe becomes low and simplifying its structure. <P>SOLUTION: The negative pressure supply device 10 for a brake booster comprises a negative pressure supply section 41 which communicates with a bypass passage 20 for bypassing a part of suction air flowing through the intake pipe 14 and directly supplies the negative pressure in the suction pipe to the brake booster 12, and an air ejector section 40 which is arranged in the bypass passage 20 and supplies the negative pressure to the brake booster 12 by boosting the nagative pressure in the intake pipe. An inlet (communication passage 17a) of the bypass passage 20 is arranged at a position downstream than an idling position of a throttle valve 16 arranged on the intake pipe 14, and upperstream than a first idling angle position. The communication with the bypass passage 20 in the negative pressure supply section 41 is performed through the air ejector section 40. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a negative pressure supply device for a brake booster that supplies an intake pipe negative pressure of an engine intake system to a brake booster installed in a vehicle. More specifically, the present invention relates to a brake booster negative pressure supply device capable of obtaining a sufficient intake pipe negative pressure with a simple configuration.

In general, a brake booster, which is a booster, is attached to a brake master cylinder constituting a brake system of a vehicle. This brake booster is operated by the intake pipe negative pressure of the engine intake system.
Here, the intake pipe negative pressure changes according to the operating state of the engine, and an intake pipe negative pressure sufficient to operate the brake booster during idling or steady operation can be obtained. When the opening of the throttle valve is the first idle opening, such as during operation of the shoner, sufficient intake pipe negative pressure may not be obtained. For this reason, the intake pipe negative pressure is increased by the air ejector and supplied to the brake booster so that a sufficient intake pipe negative pressure is always obtained.

  However, when the air ejector is always operable, air is constantly flowing from the air ejector air inlet to the intake pipe downstream of the throttle valve through the air outlet during engine operation (particularly during idling operation). End up. As a result, the accuracy of the air flow rate has been reduced during the air flow rate control in the air-fuel ratio control of the engine.

  For this reason, the air ejector is operated only in a situation where the intake pipe negative pressure becomes small, and a sufficient negative pressure is always supplied to operate the brake booster. A negative pressure supply device has been proposed in which the accuracy of the flow rate is not lowered (Patent Document 1). In this negative pressure supply device, a negative pressure responsive valve is provided in the air inflow passage of the air ejector, and when the intake pipe negative pressure is smaller than a predetermined value, the negative pressure responsive valve is opened to activate the air ejector to reduce the intake pipe negative pressure. When the intake pipe negative pressure is larger than a predetermined value, the negative pressure responsive valve is closed to stop the operation of the air ejector and the intake pipe negative pressure can be supplied to the brake booster as it is. .

Japanese Patent Application Laid-Open No. 2004-243837

However, in the above-described negative pressure supply device for a brake booster, the first passage for supplying the intake pipe negative pressure as it is to the brake booster and the air ejector are actuated to increase the intake pipe negative pressure and supply it to the brake booster. There is a second passage for the purpose. That is, there are two systems of negative pressure supply passages (exhaust passages for the brake booster) to the brake booster. For this reason, when the air ejector is activated to increase the intake pipe negative pressure to supply the brake booster, a check valve is provided in each passage so that the exhaust from the brake booster does not flow backward from the first passage to the second passage. There was a need.
Thus, the above-described negative pressure supply device for a brake booster has a problem that the structure is complicated because there are two systems of negative pressure supply (exhaust) passages and check valves are provided in each of them.

  Therefore, the present invention has been made to solve the above-described problems, and always supplies sufficient negative pressure to operate the air booster and operate the brake booster only when the intake pipe negative pressure becomes small. It is another object of the present invention to provide a negative pressure supply device for a brake booster that can be simplified and can be simplified in structure.

  A negative pressure supply device for a brake booster according to the present invention made to solve the above problem is a negative pressure supply device for supplying an intake pipe negative pressure of an engine intake system to a brake booster mounted on a vehicle. A negative pressure supply unit that communicates with a bypass passage that bypasses a part of the air flowing in the pipe and supplies the intake pipe negative pressure to the brake booster as it is, and is disposed in the bypass passage to increase the intake pipe negative pressure. An air ejector section that supplies the brake booster, and an inlet of the bypass passage is downstream of an idling position of a throttle valve disposed in the intake pipe and upstream of a first idle opening position. It is arrange | positioned and the communication to the said bypass channel in the said negative pressure supply part is performed in the said air ejector part, It is characterized by the above-mentioned.

  In this negative pressure supply device for a brake booster, when the throttle valve is at the idling opening position, the intake pipe negative pressure acts on both the inlet and outlet of the bypass passage. As a result, the air ejector portion is deactivated, and the intake pipe negative pressure is supplied as it is to the brake booster by the negative pressure supply portion. At this time, the brake booster is exhausted through the air ejector section. When the throttle valve is at the idling opening position, intake pipe negative pressure sufficient to operate the brake booster is obtained.

  On the other hand, when the throttle valve is at the first idle opening position, a sufficient intake pipe negative pressure may not be obtained. However, in this brake booster negative pressure supply device, when the throttle valve is at the first idle opening position, the inlet of the bypass passage is opened to the atmosphere, while the intake pipe negative pressure acts on the outlet of the bypass passage. For this reason, air flows into the air ejector portion, the air ejector portion is activated, and the intake pipe negative pressure increased by the air ejector portion is supplied to the brake booster.

  As described above, the air ejector is operated only when the intake pipe negative pressure is small (when the throttle valve is at the first idle opening position) even if the air ejector is connected to the bypass passage in the negative pressure supply unit. Therefore, it is possible to always supply a negative pressure sufficient to operate the brake booster. Then, by communicating with the bypass passage in the negative pressure supply section by the air ejector section, the negative pressure supply path to the brake booster (exhaust passage of the brake booster) is made common and becomes one system. For this reason, when there are two systems of negative pressure supply passages (the passage of the air ejector portion and the passage of the negative pressure supply portion) as in the prior art, the exhaust of the brake booster generated when the air ejector portion is operating No back flow occurs. Accordingly, there is no need to provide a check valve in the negative pressure supply passage. This reduces the negative pressure supply passage to the brake booster and eliminates the need for a check valve, so that a very simple device configuration can be achieved.

  That is, according to the negative pressure supply device for a brake booster of the present invention, it is possible to always supply a negative pressure sufficient to operate the brake booster by operating the air ejector only in a situation where the negative pressure of the intake pipe becomes small. At the same time, the structure can be simplified. Further, since the air ejector operates only in a situation where the intake pipe negative pressure becomes small, it is possible to prevent the accuracy of the air flow rate from being lowered during the air flow rate control in the air-fuel ratio control of the engine.

  Another embodiment of a negative pressure supply device for a brake booster according to the present invention made to solve the above problems is a negative pressure supply device that supplies an intake pipe negative pressure of an engine intake system to a brake booster mounted on a vehicle. A negative pressure supply unit that communicates with a bypass passage that bypasses a part of the air flowing in the intake pipe and supplies the intake pipe negative pressure to the brake booster as it is, and is disposed in the bypass passage, An air ejector portion that is supplied to the brake booster after being increased; and an opening / closing means that is disposed upstream of the air ejector portion of the bypass passage and opens and closes the bypass passage, and the bypass in the negative pressure supply portion The communication with the passage is performed in the air ejector section.

  In this brake booster negative pressure supply device, when the bypass passage is closed by the opening / closing means, air does not flow into the air ejector portion, so that the air ejector portion is deactivated. At this time, intake pipe negative pressure acts in the bypass passage. For this reason, exhaust from the brake booster is performed via the air ejector section, and the intake pipe negative pressure at that time is supplied to the brake booster as it is by the negative pressure supply section.

  On the other hand, when the bypass passage is opened by the opening / closing means, air flows into the air ejector portion, and the air ejector portion is activated. For this reason, the air ejector portion is activated, and the intake pipe negative pressure increased by the air ejector portion is supplied to the brake booster.

  In this way, by communicating with the bypass passage in the negative pressure supply section by the air ejector section, the negative pressure supply path to the brake booster (exhaust passage of the brake booster) is shared and becomes one system. Therefore, when there are two systems of negative pressure supply passages as in the prior art (the negative pressure supply passage of the air ejector portion and the negative pressure supply passage of the negative pressure supply portion), it occurs when the air ejector portion is operating. There is no exhaust backflow from the brake booster. Accordingly, there is no need to provide a check valve in the negative pressure supply passage. This reduces the negative pressure supply passage to the brake booster and eliminates the need for a check valve, so that a very simple device configuration can be achieved.

Further, by opening the bypass passage by the opening / closing means in a situation where the intake pipe negative pressure is reduced, the negative pressure sufficient to operate the air booster and operate the brake booster only in the situation where the intake pipe negative pressure is reduced. Pressure can always be supplied.
Therefore, the negative pressure supply device for a brake booster according to another embodiment of the present invention always supplies sufficient negative pressure to operate the brake booster by operating the air ejector only in a situation where the negative pressure of the intake pipe becomes small. In addition, the structure can be simplified. Further, since the air ejector operates only in a situation where the intake pipe negative pressure becomes small, the accuracy of the air flow rate does not deteriorate during the air flow rate control in the air-fuel ratio control of the engine.

Here, in the above-described negative pressure supply device for a brake booster, a device that opens and closes with a temperature-sensitive medium may be used as the opening and closing means. Specifically, the temperature-sensitive medium may be operated by heat transfer using the engine as a heat source.
As a result, the bypass passage can be opened and closed by the opening / closing means when the engine is cold and when the engine is warm, and the air ejector portion can be brought into an operating state or an inoperative state. By opening the bypass passage with the opening / closing means when the engine is cold when the intake pipe negative pressure is low, the air ejector is operated only when the intake pipe negative pressure is low and the brake booster is operated. Sufficient negative pressure can always be supplied.
In addition, by using an opening / closing means that opens and closes with a temperature-sensitive medium, the structure of the opening / closing means can be simplified, and the opening / closing means can be made small and light.

  Thus, by using an opening / closing means that opens and closes with a temperature-sensitive medium, a negative pressure sufficient to operate the air booster and operate the brake booster only when the engine is cold when the intake pipe negative pressure is low. Can be always supplied, and the structure can be simplified. Further, since the air ejector operates only in a situation where the intake pipe negative pressure becomes small, the accuracy of the air flow rate does not deteriorate during the air flow rate control in the air-fuel ratio control of the engine.

  In the above-described negative pressure supply device for a brake booster, it is preferable that the negative pressure supply unit, the air ejector unit, and the opening / closing means are integrated with a throttle body including the throttle valve.

  Thereby, since it is not necessary to install the negative pressure supply device as a single unit, a fixing tool that has been conventionally required is not required, and piping to the negative pressure supply device is also unnecessary. This eliminates the need for a pipe mounting portion and a vehicle fixing portion in the negative pressure supply device, and it can be said that the configuration of the negative pressure supply device is also simplified in this respect.

  In addition, since a fixture is unnecessary and piping to a negative pressure supply apparatus is also unnecessary, the total weight reduction and cost reduction of a negative pressure supply apparatus are achieved. In addition, since the piping to the negative pressure supply device is not required, the length of the bypass passage is shortened, so that the pressure loss in the piping is reduced, so that the performance of the negative pressure supply device is improved.

  According to the negative pressure supply device for a brake booster according to the present invention, as described above, a negative pressure sufficient to operate the brake booster by operating the air ejector only when the intake pipe negative pressure becomes small is always supplied. In addition, the structure can be simplified.

(First embodiment)
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a most preferred embodiment embodying a negative pressure supply device for a brake booster according to the present invention will be described in detail based on the drawings. Therefore, a negative pressure supply device for a brake booster according to an embodiment will be described with reference to FIGS. FIG. 1 is a diagram schematically showing the structure of a negative pressure supply device for a brake booster according to a first embodiment, and shows a state where a throttle valve is at an idling opening position. FIG. 2 is a diagram schematically showing the structure of the negative pressure supply device for brake booster according to the first embodiment, and shows a state in which the throttle valve is at the first idle opening position. FIG. 3 is a partial cross-sectional view of a throttle valve control device in which a negative pressure supply device for a brake booster is integrated.

  As shown in FIGS. 1 and 2, the brake booster negative pressure supply device 10 comprises an intake system of an engine 13 in a brake booster 12 attached to a brake master cylinder 11 mounted on a vehicle, and an air cleaner 15 at the tip. Is a device for supplying negative pressure (intake pipe negative pressure) in the intake pipe 14 to which is attached. In this negative pressure supply device 10 for a brake booster, a bypass passage 20 for bypassing a part of the air flowing in the intake pipe 14, an air suction passage 22 communicated with the brake booster 12 via an air suction pipe 21, A communication path 23 that connects the bypass path 20 and the air suction path 22 is formed in the housing 25.

Here, the bypass passage 20 is connected to communication passages 17 a and 17 b formed in the throttle body 17 and communicating with the intake pipe 14. That is, the passage constituted by the bypass passage 20 and the communication passages 17a and 17b corresponds to the “bypass passage” of the present invention.
The inlet of the bypass passage 20 (the communication passage 17a) is downstream of the idling opening position (see FIG. 1) of the throttle valve 16 and upstream of the first idle opening position (see FIG. 2). Is arranged. On the other hand, the outlet of the bypass passage 20 (communication passage 17 b) is disposed between the throttle valve 16 and the engine 13.

In the middle of the bypass passage 20, a throttle portion 26 whose passage cross-sectional area gradually decreases is formed by a tapered inner wall surface, and the communication passage 23 communicates where the cross-sectional area of the throttle portion 26 is minimized. .
As a result, as shown in FIG. 2, when the throttle valve 16 is in the first idle opening position, air flows into the bypass passage 20, so that negative pressure is generated by the air flow passing through the throttle portion 26, and the throttle valve 16. The intake pipe negative pressure increased more than the intake pipe negative pressure in the intake pipe 14 on the further downstream side is supplied to the brake booster 12 through the communication passage 23, the air suction passage 22 and the air suction pipe 21. Yes. That is, when the throttle valve 16 is at the first idle opening position, the air ejector section 40 is configured by the bypass passage 20, the throttle portion 26, and the communication passage 23.

  As shown in FIG. 1, when the throttle valve 16 is at the idling opening position, the intake pipe negative pressure in the intake pipe 14 on the downstream side of the throttle valve 16 acts on the entire bypass passage 20. The intake pipe negative pressure is supplied as it is to the brake booster 12 through the bypass passage 20, the communication passage 23, the air suction passage 22, and the air suction pipe 21. That is, when the throttle valve 16 is at the idling opening position, the bypass passage 20 and the communication passage 23 constitute the negative pressure supply unit 41.

  As described above, in the negative pressure supply device 10 for the brake booster, the air ejector portion 40 and the negative pressure supply portion 41 share the communication passage 23, and the negative pressure supply portion 41 communicates with the bypass passage 20 through the air ejector portion 40. As a result, the negative pressure supply passage (exhaust passage of the brake booster) to the brake booster 12 is made into one system. For this reason, when there are two systems of negative pressure supply passages as in a conventional brake booster negative pressure supply device having an air ejector portion and a negative pressure supply portion, negative pressure is supplied when the air ejector portion is operating. Since no reverse flow of the exhaust gas from the negative pressure supply passage of the air outlet to the negative pressure supply passage of the air ejector portion occurs, there is no need to provide a check valve in the negative pressure supply passage. That is, according to the negative pressure supply device 10 for the brake booster, the negative pressure supply passage to the brake booster 12 is reduced to one system and a check valve is not required, so that a very simple device configuration can be achieved. .

  As shown in FIG. 3, the brake booster negative pressure supply device 10 is supported by a throttle body 17 in which a part of the intake pipe 14 of the engine 13 is formed, and is rotatably supported in the throttle body 17. The throttle valve 16 is assembled and integrated with a known throttle valve control device 18 that includes a throttle valve 16 and a drive mechanism (such as a motor and a gear) for driving (opening and closing) the throttle valve 16. Specifically, the housing 25 is attached to the throttle body 17 via a seal member so that the bypass passage 20 formed in the housing 25 is connected to the communication passages 17a and 17b formed in the throttle body 17. .

  Thus, since the brake booster negative pressure supply device 10 is integrated with the throttle body 17, it is not necessary to install the brake booster negative pressure supply device 10 alone as in the prior art. The fixing tool is no longer necessary, and piping for connecting the brake booster negative pressure supply device and the intake pipe is also unnecessary. For this reason, the total weight reduction and cost reduction of the negative pressure supply apparatus 10 for brake boosters can be aimed at. Further, since the piping to the brake booster negative pressure supply device 10 becomes unnecessary, the pressure loss is reduced by the length of the bypass passage 20, so that the performance of the brake booster negative pressure supply device 10 is improved. Can be planned.

Next, the operation of the brake booster negative pressure supply apparatus 10 having the above-described configuration will be described. First, when the engine 13 is idling, that is, when the throttle valve 16 is at the idling opening position shown in FIG. 1, a negative pressure sufficient to operate the brake booster 12 is generated in the intake pipe 14. At this time, the intake pipe negative pressure generated in the intake pipe 14 acts on both the inlet / outlet (communication paths 17a and 17b) of the bypass passage 20. Then, since air does not flow into the bypass passage 20, air does not pass through the throttle portion 26. For this reason, the ejector part 40 will be in an operation stop state. As a result, the intake pipe negative pressure in the intake pipe 14 acts on the entire bypass passage 20, so that the negative pressure supply unit 41 keeps the intake pipe negative pressure in the intake pipe 14 as it is, the bypass passage 20, the communication passage 23, the air The brake booster 12 is supplied through the suction passage 22 and the air suction pipe 21.
Even during steady operation of the engine 13, the negative pressure supply unit 41 supplies the intake pipe negative pressure in the intake pipe 14 to the brake booster 12 as it is, as described above.

  On the other hand, when the engine 13 is warming up, that is, when the throttle valve 16 is in the first idle opening position shown in FIG. 2, there is not enough negative pressure in the intake pipe 14 to operate the brake booster 12. There is a case. At this time, the inlet of the bypass passage 20 (communication passage 17a) is opened to the atmosphere, and the intake pipe negative pressure in the intake pipe 14 acts on the outlet of the bypass passage (communication passage 17b). Then, a part of the air flowing in the intake pipe 14 from the air cleaner 15 toward the throttle valve 16 flows through the bypass passage 20. Thereby, since air passes through the throttle part 26, the ejector part 40 is in an operating state. As a result, negative pressure is generated by the air flow passing through the throttle portion 26, and the intake pipe negative pressure that is higher than the intake pipe negative pressure in the intake pipe 14 on the downstream side of the throttle valve 16 becomes the communication passage 23, the air The brake booster 12 is supplied through the suction passage 22 and the air suction pipe 21. At this time, the backflow of exhaust from the brake booster 12 does not occur.

  As described above, according to the brake booster negative pressure supply device 10 according to the first embodiment, there is a possibility that the intake pipe negative pressure sufficient to operate the brake booster 12 may not be obtained. Is at the first idle opening position, the air ejector section 40 increases the intake pipe negative pressure in the intake pipe 14 and supplies it to the brake booster 12. On the other hand, when the opening of the throttle valve 16 at which the intake pipe negative pressure sufficient to operate the brake booster 12 is at the idle opening position, the negative pressure supply unit 41 causes the intake pipe negative pressure in the intake pipe 14 to be reduced. Is supplied to the brake booster 12 as it is. Therefore, the negative pressure sufficient to operate the brake booster 12 by operating the air ejector section 40 can be always supplied only in a situation where the negative pressure of the intake pipe in the intake pipe 14 becomes small. In addition, during the idling operation of the engine 13, it is possible to prevent the inflow of excess air into the engine 13 and eliminate the deterioration in accuracy of the air flow rate control in the air-fuel ratio control of the engine 13.

  In the negative pressure supply device 10 for the brake booster, the air ejector portion 40 and the negative pressure supply portion 41 share the communication passage 23, and the negative pressure supply portion 41 communicates with the bypass passage 20 via the air ejector portion 40. Is going. As a result, the negative pressure supply passage (exhaust passage of the brake booster) to the brake booster 12 can be reduced to one system, and a check valve is not required, so that a very simple device configuration can be achieved.

  Here, the brake booster negative pressure supply device 10 according to the first embodiment can be modified like the brake booster negative pressure supply device 10a shown in FIG. FIG. 4 is a view showing a modification of the negative pressure supply device for brake booster according to the first embodiment. In this negative pressure supply device 10a for brake booster, the air ejector portion 40a is configured as follows.

In other words, a cylindrical nozzle 42 having an outer peripheral tip formed in a tapered shape is interposed in the throttle portion 26. The outer periphery of the nozzle 42 communicates with the bypass passage 20 and the inner periphery of the nozzle 42 communicates with the communication passage 23. Accordingly, in the middle of the bypass passage 20, negative pressure is generated by the air flow passing through the venturi between the outer periphery of the tip end of the nozzle 42 and the throttle portion 26, thereby causing the inside of the intake pipe 14 on the downstream side of the throttle valve 16. An air ejector portion 40a for increasing the intake pipe negative pressure is configured.
Also, the brake booster negative pressure supply device 10a including the air ejector portion 40a configured as described above can obtain the same effects as those of the first embodiment.

(Second Embodiment)
Next, a second embodiment will be described. The basic configuration of the second embodiment is the same as that of the first embodiment, but is different in that it has a throttle valve arrangement position and an opening / closing valve that opens and closes a bypass passage. For this reason, in the following, the same components as those in the first embodiment are denoted by the same reference numerals, the description thereof will be omitted as appropriate, and differences will be mainly described.

  Therefore, a negative pressure supply device for a brake booster according to a second embodiment will be described with reference to FIG. FIG. 5 is a diagram schematically showing the structure of the negative pressure supply device for a brake booster according to the second embodiment. In the brake booster negative pressure supply device 50, an open / close valve 60 is disposed in the bypass passage 20 upstream of the throttle portion 26. The opening / closing valve 60 is a known electromagnetic valve (VSV) and is opened / closed based on a command from an engine controller (ECU) (not shown). In the present embodiment, when the intake pipe negative pressure in the intake pipe 14 becomes a predetermined value (a value at which the brake booster 12 cannot be operated, for example, −35 kPa) or less, the opening / closing valve 60 is opened, and the bypass passage 20 Is opened (the communication passage 17a and the bypass passage 20 communicate with each other).

  The inlet of the bypass passage 20 (communication passage 17a) is disposed between the air cleaner 15 and the throttle valve 16. On the other hand, the outlet of the bypass passage 20 (communication passage 17 b) is disposed between the throttle valve 16 and the engine 13. That is, unlike the first embodiment, the throttle valve 16 is disposed between the inlet and outlet of the bypass passage 20.

  In such a negative pressure supply device 50 for a brake booster, when a negative pressure sufficient to operate the brake booster 12 is generated in the intake pipe 14, the on-off valve 60 is closed. Since air does not flow into the passage 20, the air does not pass through the throttle portion 26. For this reason, the ejector unit 40 is deactivated, and the negative pressure supply unit 41 causes the intake pipe negative pressure in the intake pipe 14 to remain as it is through the bypass passage 20, the communication passage 23, the air suction passage 22, and the air suction pipe 21. , Supplied to the brake booster 12.

  When the intake pipe negative pressure in the intake pipe 14 falls below a value at which the brake booster 12 cannot be operated, the on-off valve 60 is opened. For this reason, a part of the air flowing in the intake pipe 14 from the air cleaner 15 toward the throttle valve 16 flows through the bypass passage 20. Thereby, since air passes through the throttle part 26, the ejector part 40 is in an operating state. As a result, negative pressure is generated by the air flow passing through the throttle portion 26, and the intake pipe negative pressure that is higher than the intake pipe negative pressure in the intake pipe 14 on the downstream side of the throttle valve 16 becomes the communication passage 23, the air The brake booster 12 is supplied through the suction passage 22 and the air suction pipe 21.

  As described above, according to the negative pressure supply device 50 for a brake booster according to the second embodiment, when the intake pipe negative pressure sufficient to operate the brake booster 12 cannot be obtained, the on-off valve 60 Is opened, the intake pipe negative pressure in the intake pipe 14 is increased by the air ejector section 40 and supplied to the brake booster 12. On the other hand, when the intake pipe negative pressure sufficient to operate the brake booster 12 is obtained, the intake valve negative pressure in the intake pipe 14 is maintained as it is by the negative pressure supply unit 41 because the open / close valve 60 is closed. The brake booster 12 is supplied. Therefore, the negative pressure sufficient to operate the brake booster 12 by operating the air ejector section 40 can be always supplied only in a situation where the negative pressure of the intake pipe in the intake pipe 14 becomes small.

  In the brake booster negative pressure supply device 50, the air ejector unit 40 and the negative pressure supply unit 41 share the communication path 23, and the negative pressure supply unit 41 communicates with the bypass path 20 via the air ejector unit 40. Is going. As a result, the negative pressure supply passage (exhaust passage of the brake booster) to the brake booster 12 can be reduced to one system, and a check valve is not required, so that a very simple device configuration can be achieved.

  Here, instead of the opening / closing valve (electromagnetic valve) 60, an opening / closing valve using a temperature sensitive medium may be used. Therefore, an opening / closing valve using bimetal as a temperature sensitive medium and an opening / closing valve using shape memory alloy (SMA) will be described with reference to FIGS. FIG. 6 is a plan view showing the shape of the valve chamber of the open / close valve using bimetal. FIG. 7 is a cross-sectional view showing a schematic configuration of an on-off valve (opened state) using a bimetal when the engine is cold. FIG. 8 is a cross-sectional view showing a schematic configuration of an on-off valve (opened state) using a bimetal when the engine is warm. FIG. 9 is a cross-sectional view showing a schematic configuration of an on-off valve (opened state) using a shape memory alloy when the engine is cold. FIG. 10 is a plan view showing the shape of the valve body shown in FIG. FIG. 11 is a cross-sectional view showing a schematic configuration of an on-off valve (valve closed state) using a shape memory alloy when the engine is warm.

  First, an open / close valve using bimetal as a temperature sensitive medium will be described. As shown in FIGS. 7 and 8, the opening / closing valve 70 has a plurality of (eight in the present embodiment) convex portions 72a formed on the bottom surface at predetermined intervals as shown in FIG. A dish-shaped bimetal 71 which is a valve body is disposed. 7 and 8 show a cross section taken along line AA shown in FIG. On the downstream side of the valve chamber 72, a valve seat 73 is formed in which the bimetal 71 is in contact with or separated from the communication portion with the bypass passage 20. A spring 74 is disposed on the opposite side of the valve seat 73 across the bimetal 71, and the outer edge of the bimetal 71 is pressed against the convex portion 72 a formed on the bottom surface of the valve chamber 72 at a predetermined interval by the spring 74. Thus, the bimetal 71 is held and fixed in the valve chamber 72.

  As a result, as shown in FIG. 7, when the bimetal 71 is separated from the valve seat 73, the upstream side and the downstream side of the valve chamber 72 communicate with each other through the convex portion 72a. The valve opens. On the other hand, as shown in FIG. 8, when the bimetal 71 comes into contact with the valve seat 73, the upstream side and the downstream side of the valve chamber 72 are blocked by the bimetal 71, so that the open / close valve 70 is closed.

  In the temperature range of the throttle body 17 corresponding to the time when the engine 13 is cold (for example, the water temperature is 40 ° C. or less), the bimetal 71 protrudes upstream from the valve seat 63 as shown in FIG. In the temperature range of the throttle body 17 corresponding to the time when the engine 13 is warm (for example, a water temperature of 40 ° C. or higher), the valve body 73 protrudes downstream (warps) and contacts the valve seat 73 as shown in FIG. It is configured. Thereby, the opening / closing valve 70 opens the bypass passage 20 when the engine 13 is cold, and closes the bypass passage 20 when the engine 13 is warm.

  Next, an open / close valve using a shape memory alloy as a temperature sensitive medium will be described. As shown in FIG. 9, the opening / closing valve 80 includes a first space portion 71 a formed in the throttle body 17 and communicating with the communication passage 17 a, and a second space portion 81 b formed in the housing 25 and communicating with the bypass passage 20. Thus, a valve chamber 81 is formed. A valve body 82 is disposed in the valve chamber 81.

  As shown in FIG. 10, the valve body 82 is formed with a plurality of guide portions 82 c (four in this embodiment) that move along the inner wall surface of the valve chamber 81. By these guide portions 82c, the valve body 82 moves smoothly up and down without tilting. In addition, on the upper and lower sides of the valve body 82, cylindrical convex portions 82a and 82b are formed, respectively. A shape memory alloy 84 is attached to the outer periphery of the convex portion 82a of the valve body 82, and a spring 85 is attached to the outer periphery of the convex portion 82b. Here, the other end portion of the shape memory alloy 84 is attached to the outer periphery of the annular convex portion 17c formed in the communication portion between the communication passage 17a and the first space portion 81a. The other end of the spring 85 is attached to the outer periphery of the valve seat 83. As a result, the valve body 82 is held in the valve chamber 81 by the shape memory alloy 84 and the spring 85.

  As shown in FIG. 9, when the valve body 82 is separated from the valve seat 83, the communication passage 17 a and the bypass passage 20 communicate with each other via the valve chamber 81. Become. On the other hand, as shown in FIG. 11, when the valve body 82 abuts on the valve seat 83, the communication passage 17 a and the bypass passage 20 are blocked by the valve body 82, so that the open / close valve 80 is closed.

  Here, in the temperature region of the throttle body 17 corresponding to the time when the engine 13 is cold (for example, the water temperature is 40 ° C. or less), the shape memory alloy 84 is in a contracted state as shown in FIG. Thus, the valve body 82 is separated from the valve seat 83, and in the temperature range of the throttle body 17 corresponding to the time when the engine 13 is warm (for example, the water temperature is 40 ° C. or higher), the spring 85 is brought into an extended state as shown in FIG. The valve element 82 is configured to abut against the valve seat 83 against the urging force. Thereby, the opening / closing valve 80 opens the bypass passage 20 when the engine 13 is cold, and closes the bypass passage 20 when the engine 13 is warm.

  The intake pipe negative pressure sufficient to operate the brake booster 12 may not be obtained when the engine 13 is cold. For this reason, by using the on-off valve 70 or on-off valve 80 described above, there is a possibility that the intake pipe negative pressure sufficient to operate the brake booster 12 may not be obtained. The opening / closing valve 80 is opened, and the intake pipe negative pressure in the intake pipe 14 is increased by the air ejector 40 and supplied to the brake booster 12. On the other hand, the open / close valve 70 or the open / close valve 80 is closed when the engine 13 is warm enough to obtain the intake pipe negative pressure sufficient to operate the brake booster 12. The pipe negative pressure is supplied to the brake booster 12 as it is.

Therefore, even when the opening / closing valve 70 or 80 using a temperature sensitive medium is used, the air ejector section 40 is operated to operate the brake booster 12 only in a situation where the intake pipe negative pressure in the intake pipe 14 becomes small. Sufficient negative pressure can always be supplied.
The open / close valve 70 or 80 has a very simple configuration with fewer components than the electromagnetic valve. For this reason, it is smaller and lighter than the on-off valve 60 and can be manufactured at a low cost. As a result, the brake booster negative pressure supply device 50 can be further simplified.

  It should be noted that the above-described embodiment is merely an example and does not limit the present invention in any way, and various improvements and modifications can be made without departing from the scope of the invention.

It is a figure which shows typically the structure of the negative pressure supply apparatus for brake boosters which concerns on 1st Embodiment, and shows the state which has a throttle valve in an idling opening position. It is a figure which shows typically the structure of the negative pressure supply apparatus for brake boosters which concerns on 1st Embodiment, and shows the state which has a throttle valve in the first idle opening position. It is a fragmentary sectional view of the throttle valve control device with which the negative pressure supply device for brake boosters was integrated. It is a figure which shows the modification of the negative pressure supply apparatus for brake boosters which concerns on 1st Embodiment. It is a figure which shows typically the structure of the negative pressure supply apparatus for brake boosters which concerns on 2nd Embodiment. It is a top view which shows the shape of the valve chamber of the on-off valve which uses a bimetal. It is sectional drawing which shows schematic structure of the on-off valve (valve open state) using the bimetal at the time of engine cold. It is sectional drawing which shows schematic structure of the on-off valve (valve open state) using the bimetal at the time of engine warm. It is sectional drawing which shows schematic structure of the on-off valve (valve open state) using the shape memory alloy at the time of engine cold. It is a top view which shows the shape of the valve body shown in FIG. It is sectional drawing which shows schematic structure of the on-off valve (valve closed state) using the shape memory alloy at the time of engine warm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Brake booster negative pressure supply apparatus 11 Brake master cylinder 12 Brake booster 13 Engine 14 Intake pipe 15 Air cleaner 16 Throttle valve 17 Throttle body 17a, 17b Communication path 18 Throttle valve control apparatus 20 Bypass path 21 Air suction piping 22 Intake suction path 23 Communication passage 25 Housing 26 Restriction section 40 Air ejector section 41 Negative pressure supply section

Claims (4)

In the negative pressure supply device that supplies the intake pipe negative pressure of the engine intake system to the brake booster mounted on the vehicle,
A negative pressure supply unit that communicates with a bypass passage that bypasses a part of the air flowing in the intake pipe, and supplies the intake pipe negative pressure to the brake booster as it is;
An air ejector portion that is disposed in the bypass passage and increases the intake pipe negative pressure to be supplied to the brake booster;
An inlet of the bypass passage is disposed downstream of an idling position of a throttle valve disposed in the intake pipe and upstream of a first idle opening position;
The negative pressure supply device for a brake booster, wherein the negative pressure supply unit communicates with the bypass passage through the air ejector unit. In the negative pressure supply device that supplies the intake pipe negative pressure of the engine intake system to the brake booster mounted on the vehicle,
A negative pressure supply unit that communicates with a bypass passage that bypasses a part of the air flowing in the intake pipe, and supplies the intake pipe negative pressure to the brake booster as it is;
An air ejector portion that is disposed in the bypass passage and increases the intake pipe negative pressure to be supplied to the brake booster;
An opening / closing means that is disposed upstream of the air ejector portion of the bypass passage and opens and closes the bypass passage;
The negative pressure supply device for a brake booster, wherein the negative pressure supply unit communicates with the bypass passage through the air ejector unit. In the negative pressure supply device for a brake booster according to claim 2,
The negative pressure supply device for a brake booster, wherein the opening / closing means is opened / closed by a temperature sensitive medium. The negative pressure supply device for a brake booster according to any one of claims 1 to 3,
The negative pressure supply device for a brake booster, wherein the negative pressure supply unit, the air ejector unit, and the opening / closing means are integrated with a throttle body including a throttle valve disposed in the intake pipe.

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