JPH036535Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention and Field of Application] The present invention relates to an automobile vacuum booster used as a brake booster or clutch booster of an automobile.

[Prior art]

Vacuum boosters for automobiles are manufactured by, for example, JP-A-Sho.
As described in Japanese Patent No. 55-148642, generally, a housing formed by connecting a front shell and a rear shell is fixed to a dash panel of an automobile by bolts fixed to the rear shell.
The inside of this housing is divided into a front chamber and a rear chamber by a power piston and a diaphragm, and the front chamber is connected to the engine's intake manifold, which is the source of vacuum, through a port provided in the front shell, and is always a vacuum source. . The Hower piston is provided with a hollow shaft that passes through the rear shell in an airtight and slidable manner and projects into the passenger compartment from an opening in the dash panel. A control valve mechanism is provided for controlling, by means of a pedal, the flow of vacuum into the rear chamber and the entry of the vacuum in the front chamber into the rear end. This control valve mechanism includes a valve plunger connected to the front end of a push rod connected to a pedal at the rear end, an annular rear end of the valve plunger, and an annular shaft provided in a hollow shaft portion located on the outer circumferential side of the annular rear end. A poppet valve facing the valve seat, and a first valve that urges the poppet valve forward.
When the pedal is released, the annular rear end of the valve plunger is brought into contact with the poppet valve to close the air introduction path from the rear end opening of the hollow shaft portion to the rear chamber, and the poppet valve is removed from the annular valve seat via the valve plunger. The second spring biases the push rod backward to open the vacuum introduction path from the front chamber to the rear chamber, and the amount of lift from the annular valve seat of the poppet valve when the pedal is released is equal to the amount of lift from the annular valve seat of the poppet valve when the pedal is released. The size is set so that the air inside the chamber can quickly flow out into the front chamber after the operation, that is, the vacuum in the front chamber can be quickly introduced into the rear chamber.

[Problems with conventional technology and their technical analysis]

In the conventional technology as described above, when the pedal is depressed, the air inside the vehicle interior flows into the housing, so the control valve mechanism opens the air introduction path; The sound generated by the sudden flow of air and the sound generated by the air flowing through the air introduction path propagate into the vehicle interior, causing discomfort to the occupants. In addition, due to the large stroke required for the control valve mechanism to close the vacuum inlet passage, the pressure on the pedal to open the air inlet passage is too strong, causing the air inlet passage to open too much. Repeating the opening and closing of the introduction passage and the vacuum introduction passage at high cycles aggravates the generation of the above-mentioned noise, and furthermore, there is a problem that the invalid stroke of the pedal is large.

[Technical issues]

Therefore, the present invention has been developed to prevent the sound generated by atmospheric air flowing in from the rear end opening of the hollow shaft of the power piston from propagating into the passenger compartment, and to reduce the amount of lift of the poppet valve from the annular valve seat. It is large when the pedal is released, but small when the power piston is fully retracted.

[Technical means]

The interior of the housing, which is formed by joining a front shell and a rear shell and is fixed to a dash panel of an automobile by bolts fixed to the rear shell, is divided into a front chamber and a rear chamber by a diaphragm and a power piston. The front chamber is in constant communication with a vacuum source, and the power piston is provided with a hollow shaft portion that slidably passes through the opening of the rear shell in an airtight manner and projects into the vehicle interior through the opening of the dash panel. A valve plunger connected to the front end of a push rod whose rear end is connected to the pedal, an annular rear end of the valve plunger, and an annular valve seat provided in the hollow shaft portion so as to be located on the outer peripheral side of the annular rear end. an opposing poppet valve; a first spring that biases the poppet valve forward; and when the pedal is released, the annular rear end of the valve plunger is brought into contact with the poppet valve, and the valve plunger is inserted into the rear chamber from the rear end opening of the hollow shaft portion. At the same time, the poppet valve is separated from the annular valve seat through the valve plunger to shut off the vacuum introduction path leading from the front chamber to the rear chamber, and the poppet valve is opened through the valve plunger. A control valve mechanism is provided that includes a second spring that urges the push rod rearward so as to separate from the annular valve seat and open a vacuum introduction path from the front chamber to the rear chamber. In a vacuum booster for an automobile, a boot is provided between an opening and a rear end opening of the hollow shaft so as to cover the outer peripheral surface of the hollow shaft,
A spacer is interposed between the rear shell and the dash panel, and a flange portion interposed between the spacer and the dash panel and a bottomed cylindrical portion that protrudes into the vehicle interior through the opening of the dash panel and surrounds the boot. A cover is provided, the inner space of this cover is communicated with the engine room of the automobile through an opening provided in the spacer, so that the atmosphere in the engine room flows in from the rear end opening of the hollow shaft part, A bushing is provided on the top to stop the rear end of the second spring from retreating by coming into contact with the cover when the power piston is retreating, and after this bushing comes into contact with the cover, the power piston is further retreated. That's what I did.

[Action of technical means and effect of invention]

As a result, the above-mentioned configuration prevents foreign matter mixed in the atmosphere in the engine room from entering the sliding part of the hollow shaft and causing problems such as accelerating wear of the hollow shaft. It is possible to prevent atmospheric inflow noise generated within the hollow shaft portion and coming out from the rear end opening of the hollow shaft portion from being guided into the engine room and propagated to the passenger compartment.

In addition, the configuration described above makes effective use of the configuration described above to ensure a large amount of lift of the poppet valve when the pedal is released, while also ensuring a large lift of the poppet valve when the power piston is completely retracted. The amount of lift can be made as small as possible, and the simple structure prevents the air introduction path from opening too much when the pedal is depressed, thereby reducing the need to open and close the air introduction path and the vacuum introduction path at high cycles. Atmospheric inflow noise can be reduced, as well as ineffective strokes.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

The housing 11 of the vacuum booster 10 is formed by combining a front shell 11a and a rear shell 11b, and is fixed to a darts panel 40 that separates the engine room and the passenger compartment of the automobile by a large number of bolts 39 fixed to the rear shell 11b. .

A spacer 41 is interposed between the rear shell 11b and the dash panel 40, and a flange 42a is interposed between the spacer 41 and the dash panel 40.
A cover 42 is provided, which includes a bottomed cylindrical portion 42b that protrudes into the vehicle interior from an opening 40a of the dash panel. This cover 42 is preferably formed of a known damping steel plate.

The inside of the housing 11 is divided into a front chamber 14 and a rear chamber 15 by a power piston 12 and a diaphragm 13.
It is divided into. The power piston 12 is formed by integrally joining together a hub 12a made of resin and a pressure plate 12b made of a steel plate. The outer peripheral edge 13a of the diaphragm 13 is connected to the housing 11.
The front shell 11a and the rear shell 11b are airtightly fixed, and the diaphragm 13
The inner peripheral edge 13b of the pressure plate 12b extends from the rear side to the front side of the inner peripheral edge of the pressure plate 12b, and is tightly fixed between the inner peripheral edge of the pressure plate 12b and the hub 12a.

The front chamber 14 communicates with the intake manifold of the engine, which is a vacuum source, through a port 17 provided in the front shell 11a, and is always in vacuum.

The hub 12a of the power piston 12 passes through the rear shell 11b in an airtight and slidable manner and is attached to the cover 42.
A hollow shaft portion 12c extending within the bottomed cylindrical portion 42b of
A control valve mechanism 18 including a poppet valve 19 and a valve plunger 20 is built into the hollow shaft portion 12c. The poppet valve 19 has its rear end hermetically fixed to the inner wall of the hollow shaft portion 21c by a retainer 21, and its front end faces the annular rear end of the valve plunger 20 and the annular valve seat 12d of the hollow shaft portion 12c. A spring 22 urges the front end of the poppet valve 19 forward. Valve plunger 20
is connected to the front end of the push rod 23. Push rod 23 is connected to a pedal 38 at its rear end. The constricted portion 20a of the valve plunger 20 engages with the forked inner end of a key 24 incorporated in the radial hole 12e of the hub 12a, thereby causing the valve plunger 20 and push rod 23 to retreat relative to the hub 12a. Predetermined position (gap A in the drawing)
and B disappear).
The push rod 23 is connected to the bottomed cylindrical portion 4 of the cover 42.
It penetrates the inner diameter side of the seal member 43 attached to the hollow shaft part 2b in an airtight and slidable manner, and has a land part 23a located in the hollow shaft part 12c. A spring 25, which is stretched between the retainer 21 and the pusher 16 which is slidably installed on the push rod 23 and has its front end abutted against the front surface of the land portion 23a, brings the annular rear end of the valve plunger 20 into contact with the poppet valve 19. It also has the role of separating the poppet valve 19 from the annular valve seat 12d against the differential pressure (differential pressure between vacuum and atmospheric pressure) acting on the valve plunger 20 and the poppet valve 19 under this contact state and against the spring 22.

The state shown in the drawing shows a state in which the pedal 38 is released, and in the drawing, the rear end flange portion 16a of the bush 16 is connected to the cover 4 through the seal member 43.
The spring 25 comes into contact with the bottom of the bottomed cylindrical portion 42b of No. 2, and limits the retracted position of the rear end of the spring 25 with respect to the housing 11. The differential pressure acting on the valve plunger 20 and the poppet valve 19 and the spring 2
The sum of the two forces is greater than the rearward force applied from the pedal return spring 44 to the push rod 23 via the pedal 38, so that the front end of the push rod 23, valve plunger 20, and poppet valve 19 is pressed against the land of the push rod 23. The front surface of the portion 23a is advanced until it comes into contact with the bush 16. On the other hand, the power piston 12 is retracted from the housing 11 by a large number of bumper parts 13c protruding from the rear surface of the inner peripheral edge of the diaphragm 13.
As shown in the drawing, the poppet valve 19 is limited by contacting the inner surface of the rear shell 11b, and in the drawing, the poppet valve 19 is slightly lifted from the annular valve seat 12d. Therefore, in the state of the drawing, the rear chamber 15
is the hole 12f of the hub 12a, the slight gap between the annular valve seat 12d and the poppet valve 19, and the hub 12.
It communicates with the front chamber 14 through the hole 12g of a, and the front chamber 14
Vacuum is also supplied to the rear chamber 15 to eliminate the differential pressure between the two chambers, and the return spring 37 holds the power piston 12 at the position shown in the drawing.

When the pedal 38 is depressed in the state shown in the drawing, the push rod 23 and the valve plunger 2
0 moves forward relative to the power piston 12, and the front end of the poppet valve 19 follows due to the spring 22 and differential pressure. As a result, the poppet valve 19 comes into contact with the annular valve seat 12d, and the supply of vacuum from the front chamber 14 to the rear chamber 15 is stopped. Further, as the push rod 23 and the valve plunger 20 move forward, the annular rear end of the valve plunger 20 separates from the poppet valve 19.
The atmosphere in the engine room is exposed to the opening 4 of the spacer 41.
1a - Inside of bottomed cylindrical part 42b of cover 42 - Filter 29 - Hole 31a of boot 31 - Filter 3
0-Poppet valve 19 and valve plunger 20
It flows into the rear chamber 15 through the gap between the annular rear end and the hole 12f, a pressure difference is generated between the front chamber 14 and the rear chamber 15, and the power piston 12 moves forward. This forward movement of the power piston 12 is transmitted to the piston of the master cylinder (not shown) via the reaction disk 36 made of rubber fitted into the hole 12h of the hub 12a and the output member 33, and the reaction force from the output member 33 is transmitted to the piston of the master cylinder (not shown). is transmitted from the reaction disk 36 to the valve plunger 20.

As described above, the air inflow noise generated within the hub 12a when air flows into the rear chamber 15 is prevented from propagating to the passenger compartment by the cover 42 and is emitted into the engine room.

When the depressed pedal 38 is released, the force of the springs 25, 44 and the reaction force from the reaction disk 36 cause the valve plunger 20 and push rod 23 to retreat relative to the hub 12a. This retreat of the valve plunger 20 is
The valve plunger 20 contacts the front surface of the key 24 (the gap A disappears), and the rear surface of the key 24 contacts the hole 12e.
This process is continued until it comes into contact with the rear surface of (the gap B disappears). In the state where gaps A and B have disappeared, the annular rear end of the valve plunger 20 contacts the poppet valve 19 and lifts the poppet valve 19 from the annular valve seat 12d until the lift amount is the sum of the lift amount shown in the drawing plus the gaps A and B. be done. Therefore, the atmosphere in the rear chamber 15 is discharged into the front chamber 14 at a large flow rate, that is, the vacuum in the front chamber 14 is quickly supplied to the rear chamber 15, and the differential pressure between the two chambers is quickly reduced, causing the power piston to 12 retreats. When the power piston 12 is almost finished retracting, the rear end of the bush 16 first contacts the cover 42 via the seal member 43, causing the poppet valve 19 to close to the housing 11.
The valve plunger 20 and the push rod 23 stop retreating, and the power piston 12 retreats further, so that the annular valve seat 12d approaches the poppet valve 19, and the gap between them becomes smaller, resulting in the state shown in the drawing.

[Brief explanation of drawings]

The drawing is a sectional view showing an embodiment of the present invention. 11... Housing, 11a... Front shell, 11b... Rear shell, 12... Power piston, 13... Diaphragm, 14... Front chamber, 1
5... Rear chamber, 16... Button, 18... Control valve mechanism, 40... Dash panel, 41... Spacer, 42... Cover.

Claims (1)

[Scope of utility model registration request] The interior of the housing, which is formed by joining a front shell and a rear shell and is fixed to a dash panel of an automobile by bolts fixed to the rear shell, is divided into a front chamber and a rear chamber by a diaphragm and a power piston. The front chamber is in constant communication with a vacuum source, and the power piston is provided with a hollow shaft portion that slidably passes through the opening of the rear shell in an airtight manner and projects into the vehicle interior through the opening of the dash panel. A valve plunger connected to the front end of a push rod whose rear end is connected to the pedal, an annular rear end of the valve plunger, and an annular valve seat provided in the hollow shaft portion so as to be located on the outer peripheral side of the annular rear end. an opposing poppet valve; a first spring that biases the poppet valve forward; and when the pedal is released, the annular rear end of the valve plunger is brought into contact with the poppet valve, and the valve plunger is inserted into the rear chamber from the rear end opening of the hollow shaft portion. At the same time, the poppet valve is separated from the annular valve seat through the valve plunger to shut off the vacuum introduction path leading from the front chamber to the rear chamber, and the poppet valve is opened through the valve plunger. A control valve mechanism is provided that includes a second spring that urges the push rod rearward so as to separate from the annular valve seat and open a vacuum introduction path from the front chamber to the rear chamber. In the vacuum booster for an automobile, a boot is provided between an opening and a rear end opening of the hollow shaft so as to cover an outer circumferential surface of the hollow shaft, and a spacer is provided between the rear shell and the dash panel. and a cover consisting of a flange portion interposed between the spacer and the dash panel, and a bottomed cylindrical portion that protrudes into the vehicle interior through the opening of the dash panel and surrounds the boot, and The internal space is communicated with the engine room of the automobile through an opening provided in the spacer, so that the atmosphere in the engine room flows in from the rear end opening of the hollow shaft part, and when the power piston is retracted, the inner space is communicated with the engine room of the vehicle. A vehicle for use in an automobile, characterized in that a bush is provided which stops the rear end of the second spring from retreating when it comes into contact with the cover, and after the bush comes into contact with the cover, the power piston moves further back. Bakyum Booster.