The present invention addresses the problem of standardizing a front shell of a booster shell of a negative pressure-type booster device by modifying the shape of a reinforcement rib provided to the front shell so as to satisfy the demand for varying the installation pitch and installation angle of tie-rod holes with one and the same front shell. A front shell configuring a booster shell of a negative pressure-type booster device in combination with a rear shell includes a reinforcement rib formed by bending the shells, wherein the reinforcement rib is formed along a virtual ellipse of which the center is located at the center of the front shell, with the major axes of the ellipse disposed on a line connecting the centers of two tie-rod holes provided in the front shell.

A bracket provided on an engine body to support an intake pipe includes: a mounting part mounted on the engine body; and leg parts protruding from the mounting part to be fastened to the intake pipe, and the leg parts include brittle parts that are broken when a load is input from a brake member to the intake pipe. Accordingly, when the engine body is moved back and the intake pipe is brought into contact with the brake member due to a front-side collision of a vehicle and the intake pipe is pushed forward by a reaction load from the brake member, the leg parts are broken at the brittle parts and the intake pipe is thus separated from the mounting part of the bracket.

In order to minimize spreading, without additional parts, of connecting bolts of a pneumatic brake booster in a manner which is brought about by the deformation of a bearing surface on a booster housing before and during its assembly on a provided vehicle body part, it is proposed that the bearing surface is assigned a planar surface section in an immediately adjacent manner which is configured so as to be plane-parallel with respect to the bearing surface and so as to be axially inwardly recessed on the booster housing with a circumferential step.

In order to minimize spreading, without additional parts, of connecting bolts of a pneumatic brake booster in a manner which is brought about by the deformation of a bearing surface on a booster housing before and during its assembly on a provided vehicle body part, it is proposed that the bearing surface is assigned a planar surface section in an immediately adjacent manner which is configured so as to be plane-parallel with respect to the bearing surface and so as to be axially inwardly recessed on the booster housing with a circumferential step.

In order to realize shortened response and release times in a pneumatic brake booster for a hydraulic motor vehicle brake system, having an operating chamber which is delimited between an operating wall and a rear wall of the booster housing, the rear wall of the booster housing has at least one formation for reducing the minimum volume of the operating chamber.

A device for varying a pedal resistance of a hydraulic brake system includes at least one electroactive polymer actuator. The device further includes a reaction disc. The reaction disc has at least two polymer actuators. The at least two polymer actuators are independently controllable. Additionally, the at least two polymer actuators are arranged coaxially relative to one another.

A negative-pressure-type booster includes: a booster shell attached to a support member of a vehicle; a front shell and a rear shell which constitute the booster shell; and, at the four corners of a flat part of the rear shell, linking bolts having affixed thereto protruding parts that each protrude rearward from the flat part, the protruding parts being passed through continuous connecting holes in the support member, the negative-pressure-type booster characterized in that the linking bolts are composed of upper linking bolts arranged to the upper side of the center axis of the booster shell and lower linking bolts arranged to the lower side of the center axis of the booster shell, the protruding part of either of the upper linking bolts extending farther rearward than the protruding part of the other upper linking bolt and the respective protruding parts of the lower linking bolts.

A negative-pressure-type booster includes: a booster shell attached to a support member of a vehicle; a front shell and a rear shell which constitute the booster shell; and, at the four corners of a flat part of the rear shell, linking bolts having affixed thereto protruding parts that each protrude rearward from the flat part, the protruding parts being passed through continuous connecting holes in the support member, the negative-pressure-type booster characterized in that the linking bolts are composed of upper linking bolts arranged to the upper side of the center axis of the booster shell and lower linking bolts arranged to the lower side of the center axis of the booster shell, the protruding part of either of the upper linking bolts extending farther rearward than the protruding part of the other upper linking bolt and the respective protruding parts of the lower linking bolts.

A check valve of this negative pressure-type booster device is provided with: a cylindrical section that is integrally formed with a shell disposed on one side, communicates with a connection pipe, and is formed in a cylindrical shape protruding toward the inside of a housing; and a valve body section that is disposed inside the cylindrical section, and is axially fitted, within the cylindrical section, to the cylindrical section such that air is permitted to flow from a negative pressure chamber to the connection pipe while the air is prohibited from flowing from the connection pipe to the negative pressure chamber.

A vacuum brake booster for a motor vehicle brake system, comprising a housing having axially opposing end wall regions which are connected together via a peripheral region, wherein the end wall regions each comprise at least one receiving opening for receiving components introducing braking force or releasing braking force, wherein at least one reinforcing rib is formed in at least one end wall region. According to the invention, the reinforcing rib extends outside of an inner circle arranged concentric to the receiving opening and spans an inner circle segment which encloses an angle of at least approximately 60 and at most approximately 180.