JP3012232U - Booster for vehicle power brake unit - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a booster for a vehicle power brake unit that can provide various boost ratios. The booster has a shell 10A in which a power piston insert 40 is installed, and the piston insert is formed with an axial bore 401 penetrating therethrough. A push rod 52, one end of which is connected to an air valve 55, is removably inserted from one end of the axial bore of the power piston insert from the rear portion of the shell. Master cylinder piston with rubber seal pad 63 and master cylinder push rod 62 connected thereto
Is inserted from the front chamber of the shell into the other end of the axial bore so that it is elastically pressed by the air valve. The power piston has a recess 65 with a bottom surface for receiving the rubber seal pad therein, and the air valve cap is sleeve-shaped around the air valve and is in contact with the rubber seal pad.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle power brake unit booster, and more particularly, to a vehicle power brake unit booster that can provide various boost ratios.

[0002]

[Prior art]

 FIG. 1 shows a power brake unit 20 installed in an automobile, in which a conventional booster is provided. As shown in FIG. 2, the conventional booster has a shell 10 in which a partition plate 11 that divides a front chamber 101 and a rear chamber 102 is provided inside. A rubber diaphragm 8 covers the partition plate 11 and is connected to the partition plate 11 so that the front chamber 101 and the rear chamber 102 also serve as gas chambers. A power piston insert 4 is installed in the shell 10 and penetrates the partition plate 11. The power piston insert 4 has an inner wall which defines an axial bore 4B which extends through the insert. A pedal-operated push rod 7 having an air valve 7A connected to one end is removably inserted from the rear chamber 102 of the shell 10 into one end of the axial bore 4B of the power piston insert 4. The master piston 5A provided with a rubber seal pad 5B and the master cylinder push rod 5 connected to this piston push the rod 5 axially 4B of the power piston insert 4 so that it is elastically pushed by the air valve 7A. Is slidably inserted into the other end of the front chamber 101, and the master cylinder pushing rod 5 projects outward from the front chamber 101. When the pedal-operated push rod 7 is pushed, the air valve 7A first comes into contact with the rubber seal pad 5B of the master cylinder piston 5A, and correspondingly pushes the master cylinder push rod 5, which causes the braking action. I do.

It should be noted that the boost ratio required for an individual power brake unit of a vehicle is different than the boost ratio required for another power brake unit of another vehicle. The boost ratio is defined as the ratio between the abutment surface area of the master piston 5A and the abutment surface 7B of the air valve 7A. When the cross-sectional area of the rubber seal pad 5B is constant, increasing the contact surface area of the contact surface 7B of the air valve 7A reduces the boost ratio, and the contact surface 7B of the air valve 7A has a smaller contact ratio. The smaller the contact surface area, the larger the boost ratio.

Therefore, the contact surface area of the rubber seal pad 5B of the master piston 5A and the contact surface 7B of the air valve 7A changes according to the needs of the individual power brake unit of the automobile. When the contact surface area of the master piston 5A is changed, the axial bore 4B formed through the power piston insert 4 is changed accordingly to compensate for the change in the contact surface area of the master piston 5A. There must be. Creating a new power piston insert is relatively expensive. Therefore, it is desirable to obtain various boost ratios to suit the needs of individual vehicle brake units without having to replace the shell's power piston insert.

[0005]

[Problems to be solved by the device]

 It is an object of the present invention to provide a booster for a vehicle power brake unit, the boost ratio of which can be varied to supplement the individual needs of the vehicle power brake unit.

[0006]

[Means for Solving the Problems]

 Therefore, the booster for a vehicle power brake unit of the present invention has a shell in which a partition plate that divides into a front chamber and a rear chamber is provided. A power piston insert is installed in the shell, which insert penetrates the bulkhead plate. The power piston insert has an inner wall that defines an axial bore through the insert. A pedal actuated push rod, one end of which is connected to an air valve, is retractably inserted from the rear chamber of the shell into one end of the axial bore of the power piston insert. A master cylinder piston with a rubber sealing pad is inserted from the front chamber into the other end of the axial bore of the power piston insert so that it is elastically pressed by the air valve. A master cylinder push rod connected to the master piston projects outward from the front chamber of the shell. The power piston has a recess with a bottom surface that receives a rubber seal pad therein. An air valve cap forms a sleeve around the air valve and abuts the rubber seal pad.

In the disclosed embodiment, the first surface of the rubber sealing pad is formed integrally with and surrounds the peripheral portion abutting the bottom surface of the recess of the master piston. , An inner portion spaced from the bottom surface of the recess. Thus, a gap is formed between the bottom surface of the recess and the inner portion of the rubber seal pad. Preferably, the valve cap is a tubular member having an annular contact surface formed at one end. The annular contact surface presses the second surface of the rubber seal pad. The air valve cap may have a circular contact surface formed at one end thereof and a receiving recess formed at the other end thereof. The air valve attached to one end of the pedal actuated push rod is formed as a cylindrical member with an annular projecting portion formed in the circumferential direction provided on the upper side adjacent to one end thereof. Thus, when the tubular air valve cap is sleeved around the cylindrical air valve, the annular protruding portion of the air valve presses around the other end of the tubular air valve cap.

In order to obtain the desired boost ratio, the abutment surface of the air valve cap can be easily changed at a relatively low cost. This does not require replacement of the power piston insert to supplement the altered air valve cap. Thus, the booster made in accordance with the present invention can be used with any individual power brake unit of a vehicle.

Other features and advantages of the present invention will become more apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 3, 4 and 5, there is shown a booster for a vehicle power brake unit according to the present invention, which includes a shell 10A, a power piston insert. 40, a partition wall 37, a pair of holding plates 41, 42, a pair of rubber diaphragms 44, 45, a push rod assembly 50, and a master cylinder.

The power piston insert 40 is installed in the shell 10 A, and is fixedly held by the partition plate 37 with the piston insert 40 penetrating the partition plate 37. Thus, the shell 10A is divided into the front half 30 and the rear half 35. The inner wall of the power piston insert 40 defines an axial bore 401 that extends through the insert. A pair of retaining plates 41, 42 are fixedly and spaced about the power piston insert 40 on opposite sides of the partition plate 37. The rubber diaphragms 44, 45 divide the holding plates 41, 42 so that the front half 30 is divided into two sealing chambers 1A, 2A and the rear half 35 is also divided into two sealing chambers 3A, 4A. It covers airtightly. A through hole "P" is formed through the inner wall of the piston insert 40, which allows the third sealed chamber 3A to be connected to the axial bore 401 of the piston insert 40 as shown in FIG. Please note that they are in communication.

The push rod assembly 50 has a push rod 52 having an air valve 55 connected to one end thereof, the air valve being located at one end of the axial bore 401 of the power piston insert 40 at the rear half of the shell 10A. It is inserted from the portion 35 so as to be retractable.

The master cylinder has a rubber seal pad 63 inserted from the front half 30 to the other end of the axial bore 401 of the power piston insert 40 so as to be elastically pressed by the air valve 55. It includes a power piston 61 provided and a master cylinder pushing rod 62 which is formed integrally with the power piston 61 and projects outward from the front half portion 30 of the shell 10A. The power piston holding spring 64 presses the piston holding member 69. The piston holding member is operatively attached to the power piston insert 40 so as to hold the power piston 61 in the axial bore 401 of the power piston insert 40.

Referring to FIG. 7, the power piston 61 used in the preferred embodiment has a recess 65 with a bottom surface 66 which receives a rubber seal pad 63 therein. The rubber seal pad 63 is integrally formed with the peripheral portion 63A that abuts the bottom surface 66 of the recess 65 and the peripheral portion 63A, is surrounded by the peripheral portion 63A, and is spaced from the bottom surface 66 of the recess 65. Accordingly, it has a first surface constituted by an inner portion 63B forming a gap between the concave portion 65 and the bottom surface 66. The tubular valve cap 56 is sleeve-shaped around the air valve 55, and one end of this cap is formed with an annular contact surface 56A for pressing the second surface of the rubber seal 63. Has been done.

The air valve 55 used in the preferred embodiment is a cylindrical member with an annular protruding portion 55A formed around the member adjacent one end of the member. When the air valve cap 56 is in the form of a sleeve around the air valve 55, the annular protruding portion 55A presses the circumference of the other end of the tubular valve cap 56 opposite to the annular contact surface 56A. To do. Since changing the area of the abutment surface of the valve cap 56 changes the boost ratio, the area of the abutment surface of the valve cap 56 is relatively inexpensive, without the need to replace the piston insert 40 of the shell 10A. It can be changed easily.

The valve cap 70 shown in FIG. 8 is relatively inexpensive to manufacture and has a circular abutment surface 71 at one end 72 and a receiving recess 73 at the other end. The surface area of the circular abutment surface 71 of the valve cap 70 is different than the valve cap shown in FIG. 7, thus changing the boost ratio when used with the booster of the present invention.

FIG. 5 shows the booster of the present invention when the power brake unit is in the released position. In this state, the air valve 55 is seated on the floating control valve 59. This floating control valve is pressed by a spring member so that the pressure in the fourth sealed chamber 4A cannot enter the third sealed chamber 3A. Thus, the sealed chambers 1A, 2A, and 3A are at the same pressure and different from the pressure in the fourth sealed chamber 4A. When the push rod 52 is pushed as shown in FIG. 6, the pneumatic valve 55 moves against the bias of the spring 64 associated with the power piston and the floating control valve 59 disengages. External pressure passes through the air filter 53 and enters the first, second and third sealing chambers 1A, 2A, 3A as indicated by the arrows in FIG. Since the present invention is not directly related to the flow of pressure through the sealed chamber, a detailed description thereof will be omitted here.

During the braking action, the gap formed between the bottom surface 66 of the recess 65 of the piston 61 and the inner portion 63B of the rubber seal pad 63 provides a cushioning effect, and correspondingly, the power brake unit Note that it is disabled in the deadlock position.

Having thus described the invention, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope and spirit of the invention. Therefore, the present invention should be limited only as limited by the appended utility model registration claims.

[Brief description of drawings]

FIG. 1 is a schematic view showing a power brake unit equipped with a conventional booster installed in an automobile.

FIG. 2 is an enlarged view of a conventional booster of the power brake unit of FIG.

FIG. 3 is a front view of the booster of the power brake unit according to the present invention as viewed from the front.

4 is a cross-sectional view of the booster of the present invention taken along line IV-IV of FIG.

5 is a cross-sectional view of the booster of the present invention taken along the line VV of FIG. 3, showing the booster when the brake unit is in the released position.

FIG. 6 is a sectional view of the booster of the present invention when the brake unit attached to the booster is in the pushed position.

FIG. 7 is an enlarged partial view of the booster of the present invention showing the connection between the master piston and the air valve inserted into the axial bore of the power piston insert fixed to the booster.

FIG. 8 is a view showing a modified air valve cap used in the booster of the present invention.

[Explanation of symbols]

 1A, 2A, 3A, 4A Sealed chamber 10A Shell 30 Front half 35 Rear half 37 Partition plate 40 Power piston insert 41, 42 Holding plate 44, 45 Rubber diaphragm 50 Push rod assembly 52 Push rod 55 Air valve 55A Annular protruding part 56 Tubular Valve Cap 56A Annular Contact Surface 61 Power Piston 62 Master Cylinder Push Rod 63 Seal Pad 401 Axial Bore 63A Peripheral Part 63B Inner Part 65 Concave 66 Bottom 70 Valve Cap 71 Contact Surface

Claims (6)

[Scope of utility model registration request] 1. A shell having a partition wall plate therein, the shell being divided into a front chamber and a rear chamber by the partition wall plate, the shell being installed in the shell and penetrating the partition wall plate,
A power piston insert having an inner wall defining an axial bore and an air valve connected at one end, and retractably inserted into the end of the axial bore of the power piston insert from the rear chamber of the shell. A pedal actuated push rod, a master cylinder piston with a rubber seal pad and a master cylinder push rod connected thereto, the master cylinder piston being elastically pressed by the air valve. At the other end of the axial bore of the power piston insert from the front chamber, the master cylinder push rod projecting outward from the front chamber of the shell,
In a vehicle power brake unit booster, the power piston has a recess having a bottom surface that receives the rubber seal pad inside, and an air valve cap has a sleeve shape around the air valve. A booster for a vehicle power brake unit, which is in contact with a seal pad. 2. The rubber seal pad is integrally formed with a peripheral portion abutting the bottom surface of the concave portion and the peripheral portion, surrounded by the peripheral portion, and spaced from the bottom surface of the concave portion. The vehicle power brake unit booster according to claim 1, further comprising a first surface that is formed by an inner portion that is separated from the concave portion and forms a gap between the concave portion and the bottom surface. 3. The valve cap is a tubular member having an annular abutment surface formed at one end thereof, the annular abutment surface being on a side opposite to the first surface of the rubber seal. The booster for a vehicle power brake unit according to claim 2, which presses the second surface. 4. The vehicle power brake unit according to claim 2, wherein the air valve cap is a tubular member having a circular contact surface at one end and a receiving recess at the other end. booster. 5. The booster for a vehicle power brake unit according to claim 2, wherein the air valve is a cylindrical member adjacent to one end of the air valve and having an annular protruding portion formed in an upper circumferential direction. 6. The shell further comprises two retaining plates spaced around the power piston insert, each of the plates including each of the front chamber and the rear chamber. The booster for a vehicle power brake unit according to claim 1, wherein the booster is divided into two parts.