JPH0295968A - Pressure doubling device - Google Patents

Abstract

PURPOSE:To minimize noise generation from a working fluid by fitting a valve body with a block having a straight shunt line on No.2 passage formed with its circumferential length greater than axial length. CONSTITUTION:When stamping a brake pedal applies a forward propelling force to a rod 10, a plunger 9 moves ahead in a power piston unit 2 at a standstill, and when the atmosphere is introduced into a rear chamber 4 through No.2 passage 14, the stream of the atmosphere is diverged by a plurality of vents 30a in a block 30 to accomplish drop of its flow speed and baffling of the stream. When the brake pedal is returned, the stream of the atmosphere flowing out to the front chamber 3 from the rear 4 via No.1 passage is also diverged by the vents 30a to get drop in the flow speed and baffling of the stream. This reduces the sounding energy due to atmosphere to suppress the noise generated.

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. A first passage is defined in the power piston unit into two chambers, and has one end opening into the front chamber and the other end opening inside the power piston unit, and a first passage opening into the rear chamber and the other end opening into the power piston unit. A second passage opening into the power piston unit is provided, and a valve mechanism is provided inside the power piston unit to control opening and closing of the first passage and the second passage in conjunction with the input shaft, There is one in which 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.

(Problem to be solved by the invention) By the way, 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 then switched to open the first passage and close the second passage, the atmospheric air in the rear chamber will flow out due to the engine's intake pipe negative pressure, and these In each case, the operating noise is generated by the working fluid flowing inside the booster. In particular, 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 easily deformed by heat or atmospheric flow. The problem arises that the resistance becomes too large and 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 includes a second passage provided in a valve body constituting a power piston unit over a length along the axial direction of the valve body. The second passage is formed so that its length along the circumferential direction is larger than that of the second passage, 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) Embodiments of the present invention will be described below based on the drawings.

In FIGS. 1 and 2, l is the main body of the air pressure booster, and the main body 1 consists of a front shell IA and a rear shell IB.

The power piston unit 2 is divided into two units, a front chamber 3 and a rear chamber 4. In addition.

An engine intake pipe 25 opens into the front chamber 3. This power piston unit 2 is roughly composed of a valve body 5, a tire flamm 6, a piston plate 7, and a disc holder 8. The valve body 5 passes through the rear shell IB and extends outside the main body 1, and is held in an airtight manner so as to be slidable in the left-right direction (hereinafter referred to as the front-rear direction) with respect to the rear shell IB. ing. 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 IO is fitted into the recess 9a of the plunger 9, and the other end of the rod 10 is fitted into the recess 9a. , and is connected to a brake pedal (not shown), and the plunger 9 and rod 1O constitute an input shaft. The plunger 9 and the cylinder portion 5a of the valve body 5 have valve seats 9b and 5 at their respective rear ends.
b is formed, and a poppet valve 11 is provided in the valve body 5 behind the valve seats 9b and 5b,
This poppet valve 11 is connected to valve seats 9b and 5 by springs 12.
b so as to be able to come into contact with and separate from it. 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 is shown with one end opening into the front chamber 3 and the other end opening into the valve body 5 behind the valve seat 5b and in front of the attachment part of the poppet valve 11 to the pulp body 5. A first passage (not shown) and a second passage 14 which opens into the rear chamber 4 at one end and into the part body 5 in front of the valve seat 5b at the other end 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 a large length along the circumferential direction, the valve body 5 can be expanded without being stretched in the axial direction.

Therefore, when the poppet valve 11 is in contact with the valve seats 9b and 5b, the front chamber 3
and the rear chamber 4, both chambers 3 and 4, and the atmosphere as a working fluid source (
The rear part of the poppet valve 11 in the valve body 5 communicates with the atmosphere), and the poppet valve 1
1 and the valve seat 9b are separated, only the rear chamber 4 and the atmosphere are communicated with each other.

A block 30 having a branch channel formed of a plurality of linear ventilation holes 30a as shown in FIG. 2 is attached to the second passage 14. This block 30 is prevented from being removed by the head of a bolt 32 that connects the valve body 5 and disc 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, and the through hole 15 has a large diameter portion 15a and a large diameter portion 1.
It consists of a small diameter part 15b which is smaller in diameter than 5a. The tip of the plunger 9 faces the small diameter portion 15b,
The large diameter base end portion of the output shaft 17 is engaged with the large diameter portion 15a via the reaction disk 16, and the input shaft and output shaft 1
7 and is arranged on the same axis.

A support plate 2o is provided on the inner wall of the rear shell 1B, and the rod 31 held between the support plate 2o and the rear shell IB penetrates the power piston unit 2 and the front shell IA, and its tip or main body. It extends outward from the rod 31 and is screwed into a threaded portion formed at the tip of the rod 31 with a nut. This rod 31 is surrounded by a bellows 23 in the front chamber 3, and the front end of the bellows 23 is connected to the front shell IA.
It is fixed to the inner wall, and its rear end is fixed to the power piston unit 2. Further, a return spring 24 is provided between the front shell IA and the power piston unit 2 in the front chamber 3 to bias 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.

When a forward thrust is applied to the rod 10 by depressing the brake pedal, the plunger 9 moves forward inside the stationary power piston unit 2, and is separated from the valve seat 9b of the plunger 9 and the surface of the poppet valve 11. At the same time, the atmosphere passes through the gap and the second passage 14 into the rear chamber 4.
to go into. At this time, the poppet hartz 11 is in contact with the valve seat 5b of the hartz body 5 even before the brake pedal is depressed. By introducing this atmospheric pressure, the diaphragm 6 generates a differential pressure on both sides thereof, and a forward thrust is generated in the power piston unit 2, thereby starting a boosting operation. and,
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 rearward direction is transmitted to the power piston unit 2, while the reaction disk 16 is elastically deformed and comes into contact with the plunger 9, and as a result, the reaction force is transmitted through the plunger 9 and the rod lO. This will be transmitted to the brake pedal. 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 franchisor 9 seats on the poppet hartz 11 and becomes stationary, or if the flake pedal is further depressed, a similar operation is performed. That will happen.

When the brake pedal is released, a reaction force from the output shaft 17 in the rearward direction is transferred from the plunger 9 to the poppet hartz 1.
1, and the poppet valve 11 is connected to the valve body 5.
is separated from the valve seat 5b, and the atmosphere in the rear chamber 4 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 also 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 chamber 4 through the second passage 14, the flow of the atmosphere is divided by the plurality of ventilation holes 30a of the block 30,
Efforts are being made to reduce the flow velocity and to rectify the flow. Also,
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 divided by the plurality of ventilation holes 30a of the block 30, thereby reducing the flow velocity and streamlining the flow. .

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 that a plurality of ventilation holes 30
The block 30 having a block 30 has a different stopping means, and a stop key 33 for regulating the position of the plunger 9 is used.
By bending the end of the block 30, remove the stopper 33a.
That is.

Note that 13 is a first passage not shown in the above embodiment, which connects the inside of the power piston unit 2 and the front chamber 3.
It communicates with

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, the front chamber 3 and the rear chamber 4 are
Have you explained the case where is the vacuum-atmosphere relationship?
The present invention is not limited to this, and for example, the two chambers 3 and 4 may be in a vacuum-compressed air or atmospheric-compressed air relationship.

(Effects of the Invention) As described above, in the present invention, since the second passage is equipped with a block that forms a branch passage, the working fluid flowing through the second passage is divided by the branch passage, resulting in a decrease in flow velocity and a decrease in 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.

In addition, 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 there is also less flow resistance. Therefore, 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 longer than the length along the axial direction of the valve body, the length of the second passage in the axial direction of the valve body is not increased.
The passage area of the second passage can be set as wide as possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing an embodiment of a pressure booster according to the present invention, and FIG. 2 is a partial plan view seen from direction C in FIG. 1. 3 is a sectional view of a main part of another embodiment of the air pressure booster of the present invention, and FIG. 4 is a view seen from direction D in FIG. 3. 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 1
4...Second passage 1.7...Output shaft 30
...Block 30a...Vent hole

Claims (1)

[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 a chamber with one end opening into the front chamber and the other end opening inside the power piston unit. one passage and a second passage whose one end opens into the rear chamber and the other end opens into the inside of the power piston unit, and inside the power piston unit, the first passage and the second passage are opened in conjunction with the input shaft. A valve mechanism for controlling opening and closing of the second 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. In the air pressure booster configured to transmit thrust acting on the power piston unit to an output shaft when a pressure difference is generated between the two chambers, the second passage is connected to a valve constituting the power piston unit. The valve body 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, and the second passage is equipped with a block in which a linear branch flow path is formed. Air pressure booster.