JPH0353141B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pressure booster used in a brake device or the like.

(Prior art) Generally, a pressure booster uses the engine's intake pipe negative pressure to double the brake pedal depression force and transmit it to the master cylinder. The power piston unit is divided into two chambers;
a first passage having one end opening into the front chamber and the other end opening into the inside of the power piston unit; and a second passage having one end opening into the rear chamber and the other end opening into the inside of the power piston unit; The inside of the power piston unit is provided with a valve mechanism that controls the opening and closing of the first passage and the second passage in conjunction with the input shaft, so that the inside of the power piston unit is communicated with the atmosphere. Such a pressure booster operates the input shaft to switch the valve mechanism, creates a pressure difference between the front chamber and the rear chamber by switching the valve mechanism, and increases the power due to the pressure difference. The thrust force acting on the piston unit is transmitted to the output shaft.

(Problems to be Solved by the Invention) In this type of conventional booster, when the valve mechanism closes the first passage and opens the second passage, atmospheric air flows into the rear chamber. Therefore, if the valve mechanism is subsequently switched to open the first passage and close the second passage, the atmosphere in the rear chamber will flow out due to the engine's intake pipe negative pressure. In each case, the operating noise is generated by the working fluid flowing inside the booster. Particularly, in a one-box type vehicle in which the entire booster is installed in the driver's cab, the operating noise of the working fluid flowing inside the booster is extremely loud, and there is a strong desire to reduce the operating noise.

Therefore, it is possible to reduce the operating noise by installing sponges in each passage, but sponges have poor durability and are susceptible to deformation due to heat or atmospheric flow, and they also have resistance to atmospheric flow. becomes too large, which causes a problem in that it affects the operating speed of the power piston unit.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems, and the second passage is provided in the valve body constituting the power piston unit with a length longer than the length along the axial direction of the valve body. The second passage is formed so that its length along the circumferential direction is large, and a block having a linear branch passage is attached to the second passage.

(Function) According to this configuration, when the brake pedal is depressed and released, the flow velocity of the working fluid flowing through the second passage is reduced by passing through the branch passage of the block, and the flow is rectified. Therefore, the operating noise in the pressure booster using the working fluid is reduced.

(Example) Examples of the present invention will be described below based on the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a main body of the air pressure booster. The main body 1 consists of a front shell 1A and a rear shell 1B. The inside of the main body 1 is connected to a front chamber 3 and a rear chamber by a power piston unit 2. It is divided into two rooms, room 4 and room 4. Note that an engine intake pipe 25 opens into the front chamber 3. This power piston unit 2 is generally composed of a valve body 5, a diaphragm 6, a piston plate 7, and a disk holder 8. The valve body 5 passes through the rear shell 1B and extends outside the main body 1, and is airtightly inserted into the rear shell 1.
It is held slidably in the left-right direction (hereinafter, this direction is referred to as the front-back direction) in the figure with respect to B. A plunger 9 is fitted into the cylinder portion 5a of the valve body 5, a spherical end which is one end of the rod 10 is fitted into the recess 9a of the plunger 9, and the other end of the rod 10 is fitted with a recess 9a. It is connected to a brake pedal (not shown), and the plunger 9 and rod 10 constitute an input shaft. Valve seats 9b, 5b are formed at the rear end portions of the plunger 9 and the cylinder portion 5a of the valve body 5, respectively, and a poppet valve 11 is provided inside the valve body 5 behind the valve seats 9b, 5b. The poppet valve 11 is urged by a spring 12 so as to be able to come into contact with and separate from the valve seats 9b and 5b.
In addition, when the poppet valve 11 is not in operation, as shown in FIG. 1, the poppet valve 11 is in contact with the valve seats 9b and 5b. This valve body 5 has a hole (not shown) which has one end opening into the front chamber 3 and the other end opening into the valve body 5 rearward of the valve seat 5b and forward of the attachment part of the poppet valve 11 to the valve body 5. One passage and a second passage 14 whose one end opens into the rear chamber 4 and whose other end opens into the valve body 5 forward of the valve seat 5b are formed. The length of the second passage 14 along the circumferential direction is set to be larger than the length along the axial direction of the valve body 5. By setting the length along the circumferential direction to be large, the valve body 5 can be expanded without being extended in the axial direction.

Therefore, when the poppet valve 11 is not in operation, that is, when the valve seats 9b and 5b are in contact with each other, the front chamber 3, the rear chamber 4, both chambers 3 and 4, and the atmosphere as a source of working fluid (the poppet valve in the valve body 5) The area behind 11 is in communication with the atmosphere)
When the poppet valve 11 and the valve seat 9b are separated from each other while the poppet valve 11 is in contact with the valve seat 5b, only the rear chamber 4 is communicated with the atmosphere.

The second passage 14 is equipped with a block 30 having a branch path made up of a plurality of linear ventilation holes 30a as shown in FIG. This block 30 is prevented from coming off by the head of a bolt 32 that connects the valve body 5 and disk holder 8.

A disk holder 8 is fixed to the front surface of the valve body 5 via a diaphragm 6 and a piston plate 7. A through hole 15 is formed in the disk holder 8.
5 consists of a large diameter portion 15a and a small diameter portion 15b that is smaller in diameter than the large diameter portion 15a. The tip of the plunger 9 faces the small diameter portion 15b, and the large diameter base end of the output shaft 17 is engaged with the large diameter portion 15a via the reaction disk 16. placed on the same axis.

A support plate 20 is installed on the inner wall of the rear shell 1B.
is provided, and a rod 31 held between the support plate 20 and the rear shell 1B passes through the power piston unit 2 and the front shell 1A, and its tip extends outward from the main body 1.
A nut is screwed into a threaded portion formed at the tip of the rod 31. This rod 31 is surrounded within the front chamber 3 by a bellows 23, the front end of which is fixed to the inner wall of the front shell 1A, and the rear end thereof is fixed to the power piston unit 2. Further, a return spring 24 is provided between the front shell 1A and the power piston unit 2 in the front chamber 3 for urging the power piston unit 2 rearward.

Note that 26 is a porous member having a function of dividing the air, and the porous member 26 also reduces the operational sound energy of the air flowing inside the porous member 26.

Next, the operation related to the above configuration will be explained.

Rod 1 by depressing the brake pedal.
When forward thrust is applied to the piston 0, the plunger 9 moves forward inside the stationary power piston unit 2, and the valve seat 9b of the plunger 9 separates from the surface of the poppet valve 11, and at the same time, the atmosphere fills the gap and the valve. It enters the rear chamber 4 through the second passage 14. At this time, the poppet valve 11 is in contact with the valve seat 5b of the valve body 5 even before the brake pedal is depressed. Due to the introduction of this atmospheric pressure, the diaphragm 6
A differential pressure is generated on both sides of the piston, a forward thrust is generated in the power piston unit 2, and a boosting operation is started. The thrust of the power piston unit 2 is transmitted to the output shaft 17, and the output shaft 17 is pushed forward. At this time, the reaction force from the output shaft 17 in the rear direction is applied to the power piston unit 2.
At the same time, the reaction disk 16 is elastically deformed and comes into contact with the plunger 9, and as a result, the force is transmitted to the brake pedal via the plunger 9 and the rod 10. Due to the forward movement of the power piston unit 2 in conjunction with the forward movement of the diaphragm 6, the valve seat 9b of the plunger 9 seats on the poppet valve 11 and becomes stationary, but if the brake pedal is further depressed, the same operation occurs. It will be done.

When the brake pedal is released, a rearward reaction force from the output shaft 17 is transmitted from the plunger 9 to the poppet valve 11, and the poppet valve 11 is separated from the valve seat 5b of the valve body 5, and the atmosphere in the rear chamber 4 is It flows out into the front chamber 3 through the first passage. Therefore, as the pressure in the rear chamber 4 decreases, the differential pressure between the front chamber 3 and the rear chamber 4 decreases, and the return spring 24 causes the power piston unit 2 to return to the original position shown in FIG.

Then, when the brake pedal is depressed and the atmosphere is introduced into the rear compartment through the second passage 14, the air flow is caused to flow through the plurality of ventilation holes 3 of the block 30.
The flow is divided by 0a, and the flow velocity is reduced and the flow is rectified. Further, when the brake pedal is released, the flow of air flowing from the rear chamber 4 to the front chamber 3 via the first passage is also prevented by the block 30.
The flow is divided by the plurality of ventilation holes 30a, and the flow velocity is reduced and the flow is rectified.

Therefore, the operating sound energy due to the atmosphere is reduced, and the operating sound is reduced.

Next, another embodiment will be described based on FIGS. 3 and 4.

This embodiment differs from the previous embodiment in the means for preventing the block 30 from falling off, which has a plurality of ventilation holes 30a, by bending the end of the stop key 33 that regulates the position of the plunger 9. 30 as a retaining portion 33a.
In addition, 13 is the first one not shown in the above embodiment.
This passage communicates the inside of the power piston unit 2 with the front chamber 3.

The operation of this embodiment is the same as that of the previous embodiment, so a description thereof will be omitted.

In the above embodiment, a case has been described in which the front chamber 3 and the rear chamber 4 are in a vacuum-atmosphere relationship during boosting operation, but the present invention is not limited to this.
It is also possible to have a relationship such as vacuum-compressed air or atmosphere-compressed air.

(Effects of the Invention) As described above, in the present invention, since the second passage is equipped with a block having a branch passage, the working fluid flowing through the second passage is divided by the branch passage, resulting in a decrease in the flow velocity and a decrease in the flow. Since the flow is rectified and the energy of the operating sound caused by the working fluid is reduced, the operating noise of the working fluid can be minimized.

Since the flow velocity is reduced and the flow is rectified using multiple linear branch channels, it does not deform due to heat or fluid flow, unlike when using a sponge, and it also reduces flow channel resistance. Since the number of pistons is small, the influence on the operating speed of the power piston unit can be reduced.

In addition, since the second passage is formed so that the length along the circumferential direction of the valve body is larger than the length along the axial direction of the valve body, the passage area of the second passage can be maximized as much as possible without increasing the length of the valve body in the axial direction. Can be set widely.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts showing an embodiment of the air pressure booster according to the present invention, FIG. 2 is a partial plan view seen from direction C in FIG. 1, and FIG. A cross-sectional view of the main part of another embodiment of the booster, FIG.
It is a view seen from direction D in the figure. 1...Main body, 2...Power piston unit,
3...Front chamber, 4...Rear chamber, 5...Valve body, 5b...Valve seat, 9...Plunger, 9b
... Valve seat, 10 ... Rod, 11 ... Poppet valve, 13 ... First passage, 14 ... Second passage, 1
7...Output shaft, 30...Block, 30a...Vent hole.

Claims (1)

[Scope of Claims] 1. The inside of the main body is divided into two chambers, a front chamber and a rear chamber, by a power piston unit, and the power piston unit has one end opening into the front chamber and the other end opening inside the power piston unit. A first passageway opening into the rear chamber and a second passageway opening into the rear chamber at one end and opening into the inside of the power piston unit at the other end, the inside of the power piston unit interlocking with the input shaft. a first passage and said second passage;
A valve mechanism for controlling opening and closing of the passage is provided, the inside of the power piston unit is communicated with a working fluid source having a relatively higher pressure than the front chamber, and the input shaft is actuated to switch the valve mechanism to open and close the two chambers. In the air pressure booster, the thrust force acting on the power piston unit is transmitted to the output shaft when a pressure difference is generated between the two, wherein the second passage is connected to the valve body constituting the power piston unit. A pressure booster characterized in that the length of the valve body along the circumferential direction is longer than the length along the axial direction of the valve body, and a block having a linear branch flow path is attached to the second passage. Device.