GB2114708A - Diaphragm piston for vacuum booster - Google Patents

Diaphragm piston for vacuum booster Download PDF

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Publication number
GB2114708A
GB2114708A GB08236122A GB8236122A GB2114708A GB 2114708 A GB2114708 A GB 2114708A GB 08236122 A GB08236122 A GB 08236122A GB 8236122 A GB8236122 A GB 8236122A GB 2114708 A GB2114708 A GB 2114708A
Authority
GB
United Kingdom
Prior art keywords
piston
plate
piston plate
diaphragm
power piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08236122A
Other versions
GB2114708B (en
Inventor
Akito Tsurusaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Publication of GB2114708A publication Critical patent/GB2114708A/en
Application granted granted Critical
Publication of GB2114708B publication Critical patent/GB2114708B/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16JPISTONS; CYLINDERS; SEALINGS
    • F16J3/00Diaphragms; Bellows; Bellows pistons
    • F16J3/02Diaphragms
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60TVEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/24Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being gaseous
    • B60T13/46Vacuum systems
    • B60T13/52Vacuum systems indirect, i.e. vacuum booster units
    • B60T13/569Vacuum systems indirect, i.e. vacuum booster units characterised by piston details, e.g. construction, mounting of diaphragm

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Braking Systems And Boosters (AREA)
  • Diaphragms And Bellows (AREA)

Abstract

A diaphragm piston 11 for a vacuum booster is improved to distribute evenly the stress on the surface of the piston plate 12, by the piston plate having an arcuate cross- section with a uniform curvature or a curvature gradually increasing radially toward the centre of the plate. <IMAGE>

Description

SPECIFICATION A power piston for a vacuum booster The present invention relates to an improved power piston for a vacuum booster mainly used in brake systems for vehicles.
As shown in Figure 1, the conventional power piston for this purpose has a diaphragm 1 and a piston plate 2 for supporting the diaphragm. The piston plate is conical (as shown in Figure 1) or flat (as in Figure 2). Under a negative pressure, such a piston plate is stressed particularly at its base portion adjacent to the outer periphery of a valve body 3. If the plate 2 is made of a light or thin material in order to make the device lighter in weight, it is possible that the plate will have insufficient strength to support the diaphragm.
To cope with this problem, that is, the concentration of stress at the base portion, two solutions are conceivable. One is to increase the thickness at the base portion of the plate and the other is to decrease the vertical angle of the cone (if the plate is conical). However, these solutions do not meet the requirements in the cost, weight and mounting space.
An object of the present invention is to provide a power piston which permits an even distribution of the stress on the whole pressure-receiving surface of the piston plate.
In accordance with the present invention there is provided a power piston for a vacuum booster, said power piston comprising a diaphragm fixedly mounted on a valve body, and a piston plate for supporting said diaphragm, the piston plate in axial section being arcuate.
In accordance with the present invention, it becomes possible to use a lighter material for the piston plate or make the piston plate thinner. This enables the booster to be made lighter in weight and lessens the manufacturing cost.
Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figures 1 and 2 are partially cutaway front views of two conventional power pistons; Figure 3 is a partial cutaway axial section of a power piston embodying the present invention; and Figure 4 is a similar view of another embodiment.
Referring to Figure 3, a power piston 10 embodying the present invention has a diaphragm 11 fixedly mounted on a valve body 13, and a piston plate 12 for supporting the diaphragm. As seen in Figure 3 the piston plate 12 has an inwardly arcuate cross-section with a substantially uniform curvature.
In the second embodiment of Figure 4, the piston plate is of similar shape, but has a curvature gradually increasing toward its centre.
With a piston plate of such a shape with a smaller vertical angle at the base portion and a larger angle at the peripheral area, the stress decreases at the base portion of the plate and increases at its peripheral area so that the stress will be distributed evenly over the whole surface.
This assures the required strength even if a lightweight material is used for the piston plate or if the plate is made thinner. If a metal is used as the material for the piston plate for a vacuum booster intended for ordinary cars, for example, this will make it possible to decrease the thickness of the piston plate to about 0.8 mm.
The piston plate 12 may be integral with the valve body 13 as in Figure 3, or separate therefrom and mounted in an annular groove 14 in the valve body 13, as in Figure 4.
The piston plate 12 may be provided with a reinforcing rib 1 5 at the pressure-receiving side, as required.
Claims
1. A power piston for a vacuum booster, said power piston comprising a diaphragm fixedly mounted on a valve body, and a piston plate for supporting said diaphragm, the piston plate in axial section being arcuate.
2. A power piston according to Claim 1 wherein the arcuate shape of the piston plate has a uniform curvature.
3. A power piston according to Claim 1 wherein the arcuate shape of the piston plate has a curvature which gradually increases radially inwardly.
4. A power piston according to Claim 1, 2 or 3, wherein said piston plate is integral with said valve body.
5. A power piston according to Claim 1, 2 or 3, wherein said piston plate is separate from and mounted on said valve body.
6. A power piston for a vacuum booster substantially as described with reference to and as illustrated in Figure 3 or 4 of the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A power piston for a vacuum booster The present invention relates to an improved power piston for a vacuum booster mainly used in brake systems for vehicles. As shown in Figure 1, the conventional power piston for this purpose has a diaphragm 1 and a piston plate 2 for supporting the diaphragm. The piston plate is conical (as shown in Figure 1) or flat (as in Figure 2). Under a negative pressure, such a piston plate is stressed particularly at its base portion adjacent to the outer periphery of a valve body 3. If the plate 2 is made of a light or thin material in order to make the device lighter in weight, it is possible that the plate will have insufficient strength to support the diaphragm. To cope with this problem, that is, the concentration of stress at the base portion, two solutions are conceivable. One is to increase the thickness at the base portion of the plate and the other is to decrease the vertical angle of the cone (if the plate is conical). However, these solutions do not meet the requirements in the cost, weight and mounting space. An object of the present invention is to provide a power piston which permits an even distribution of the stress on the whole pressure-receiving surface of the piston plate. In accordance with the present invention there is provided a power piston for a vacuum booster, said power piston comprising a diaphragm fixedly mounted on a valve body, and a piston plate for supporting said diaphragm, the piston plate in axial section being arcuate. In accordance with the present invention, it becomes possible to use a lighter material for the piston plate or make the piston plate thinner. This enables the booster to be made lighter in weight and lessens the manufacturing cost. Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figures 1 and 2 are partially cutaway front views of two conventional power pistons; Figure 3 is a partial cutaway axial section of a power piston embodying the present invention; and Figure 4 is a similar view of another embodiment. Referring to Figure 3, a power piston 10 embodying the present invention has a diaphragm 11 fixedly mounted on a valve body 13, and a piston plate 12 for supporting the diaphragm. As seen in Figure 3 the piston plate 12 has an inwardly arcuate cross-section with a substantially uniform curvature. In the second embodiment of Figure 4, the piston plate is of similar shape, but has a curvature gradually increasing toward its centre. With a piston plate of such a shape with a smaller vertical angle at the base portion and a larger angle at the peripheral area, the stress decreases at the base portion of the plate and increases at its peripheral area so that the stress will be distributed evenly over the whole surface. This assures the required strength even if a lightweight material is used for the piston plate or if the plate is made thinner. If a metal is used as the material for the piston plate for a vacuum booster intended for ordinary cars, for example, this will make it possible to decrease the thickness of the piston plate to about 0.8 mm. The piston plate 12 may be integral with the valve body 13 as in Figure 3, or separate therefrom and mounted in an annular groove 14 in the valve body 13, as in Figure 4. The piston plate 12 may be provided with a reinforcing rib 1 5 at the pressure-receiving side, as required. Claims
1. A power piston for a vacuum booster, said power piston comprising a diaphragm fixedly mounted on a valve body, and a piston plate for supporting said diaphragm, the piston plate in axial section being arcuate.
2. A power piston according to Claim 1 wherein the arcuate shape of the piston plate has a uniform curvature.
3. A power piston according to Claim 1 wherein the arcuate shape of the piston plate has a curvature which gradually increases radially inwardly.
4. A power piston according to Claim 1, 2 or 3, wherein said piston plate is integral with said valve body.
5. A power piston according to Claim 1, 2 or 3, wherein said piston plate is separate from and mounted on said valve body.
6. A power piston for a vacuum booster substantially as described with reference to and as illustrated in Figure 3 or 4 of the accompanying drawings.
GB08236122A 1981-12-29 1982-12-20 Diaphragm piston for vacuum booster Expired GB2114708B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19516681U JPS58100853U (en) 1981-12-29 1981-12-29 Power piston of vacuum booster

Publications (2)

Publication Number Publication Date
GB2114708A true GB2114708A (en) 1983-08-24
GB2114708B GB2114708B (en) 1986-01-08

Family

ID=16336524

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08236122A Expired GB2114708B (en) 1981-12-29 1982-12-20 Diaphragm piston for vacuum booster

Country Status (4)

Country Link
JP (1) JPS58100853U (en)
AU (1) AU555259B2 (en)
DE (1) DE3247243A1 (en)
GB (1) GB2114708B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4344188A1 (en) * 1993-12-23 1995-06-29 Teves Gmbh Alfred Negative pressure brake booster for vehicle
JP5372996B2 (en) * 2011-06-06 2013-12-18 日信工業株式会社 Negative pressure booster for automobile brakes

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3015187A1 (en) * 1980-04-19 1981-10-22 Alfred Teves Gmbh, 6000 Frankfurt BRAKE POWER AMPLIFIER FOR MOTOR VEHICLES
JPS56167547A (en) * 1980-05-26 1981-12-23 Toyota Motor Corp Booster

Also Published As

Publication number Publication date
GB2114708B (en) 1986-01-08
JPS58100853U (en) 1983-07-08
AU9193682A (en) 1983-07-07
AU555259B2 (en) 1986-09-18
DE3247243A1 (en) 1983-07-14

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19961220