JPH0331655Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is used in the technical field of automobile brake systems, and in particular, it has an assist pressure chamber adjacent to the master cylinder to shorten the push rod that is transmitted to the master cylinder. Relating to type of equipment.

(Prior Art) A brake device for an automobile is provided with a main cylinder adjacent to a master cylinder, the interior of which is an assist pressure chamber. this is,
A push rod for pushing the piston of the master cylinder extends through the assist pressure chamber. When you step on the brake pedal, this push rod changes its angle slightly, causing it to twist. To reduce this twisting, the main cylinder is made longer, and as a result, this part protrudes from the engine compartment, making it difficult to drive. There was a problem that the use of room space was hindered. However, until now, there has been no idea to deal with this problem. Another conventional example is a brake device disclosed in Japanese Patent Application Laid-Open No. 16128/1983, which detects the impact force at the time of a collision and applies sudden braking using electromagnetic force. It's not a solution to the problem.

(Purpose of the invention) In this invention, there is provided a brake device in which the axial length of the main cylinder is shortened in which the assist pressure chamber is formed adjacent to the master cylinder,
The purpose is to shorten the length of the protrusion from the engine room of the automobile, and to make effective use of space, especially in the driver's cab.

(Structure of the invention) The means in this invention connects a master cylinder having a braking hydraulic pressure chamber and a push rod that transmits the depression force from the brake pedal, and connects the push rod to an assist pressure chamber formed adjacent to the master cylinder. A concave curved surface is formed on the inner wall of the main cylinder on the side where the push rod is inserted, and a convex curved surface is formed on the side of the support member facing this, in which the support member is fitted and forms the assist pressure chamber. A brake device for an automobile includes a sealing member provided between the convex curved surface and the concave curved surface.

The effect of this invention is that by connecting the push rod to the master cylinder through the assist pressure chamber, not only can the axial length of the main cylinder that forms the assist pressure chamber in the brake device be shortened, but also Regardless of the angular displacement of the push rod, the support member follows it and the operation is smooth.

(Example) An example of this invention will be described in detail below with reference to the drawings. In the drawings, F is the front and R is the back.

The main parts of this embodiment include a brake pedal 1, a master cylinder 2 that generates braking hydraulic pressure when the brake pedal is depressed, and a master cylinder 2 that is connected to the brake pedal 1 and directly applies the brake pedal depression force to the master cylinder 2. A push rod 3 transmitting pressure to the next piston 2c, an assist pressure chamber 4a provided in a main cylinder 4 formed adjacent to the rear part of the master cylinder 2, and the push rod 3.
The main cylinder 4 has an inner wall on the side of the push rod insertion hole 4b into which the push rod 3 is inserted is formed into a concave curved surface 4c, and the support member 5 is disposed in the assist pressure chamber 4a. A convex curved surface 5a corresponding to the concave curved surface 4c is formed on the rear end surface, and a seal member 5b is formed on the convex curved surface 5a.
is provided so that the support member 5 follows the angular displacement of the push rod 3, and the pressure in the assist pressure chamber 4a is also maintained.

The details of each part will be explained below. The base end of the brake pedal 1 is pivotally supported on the vehicle body by a shaft 1b. On the other hand, a rear primary piston 2c is loosely fitted inside the cylinder body 2a of the master cylinder, and a secondary piston 2d is loosely fitted in the front part, thereby dividing a first oil chamber 2e and a second oil chamber 2f. Return springs 2g and 2h are installed between the primary piston 2c and the secondary piston 2d, and between the secondary piston 2d and the inner front end of the cylinder body 2a, respectively. and primary piston 2c
The rear end of the cylinder body 2a is positioned by coming into contact with a ring 2i fitted to the inner surface of the cylinder body 2a. 1 more
A seal 2j is attached to the outer periphery of both the secondary piston 2c and the secondary piston 2d to prevent oil leakage from the inner periphery of the cylinder body 2a. A reserve tank 6 is provided above the master cylinder 2, and communicates with the first oil chamber 2e through a relief port 6a and with the second oil chamber 2f through a relief port 6b. Further, a hydraulic passage 7a is provided in the lower part of the first oil chamber 2e, and the front wheel brake device 7 is provided with a hydraulic passage 7a.
The lower part of the second oil chamber 2f is connected to the hydraulic passage 8a.
is provided and communicated with the rear wheel brake device 8.

Further, the rear end of the primary piston 2c is provided with a recess 2k for contacting the arcuate portion 3a at the front end of the push rod 3. The arc at the bottom of the recess 2k is the arc portion 3
The radius is made larger than that of the arc a, so that the bottom of the recess 2k and the tip of the arc portion 3a are always in contact with each other even when the push rod 3 is angularly displaced.

Note that the bottom surface of the recess 2k and the end surface of the arcuate portion 3a may each be a spherical surface, an arcuate surface, or other curved surface.

A seal member 5c is provided between the support member 5 and the push rod 3 to prevent leakage between the two. Furthermore, a seal member 5 is provided between the convex curved surface 5a of the support member 5 and the inner concave curved surface 4c of the main cylinder 4.
b and a ball bearing 5d are interposed to guide the tilting movement of the support member 5 accompanying the angular displacement of the push rod 3. Support member 5 and cylinder body 2a
A spring 5e is interposed between the support member 5 and the support member 5 to urge the support member 5 rearward. Further, the concave curved surface 4c and the convex curved surface 5a may also be spherical or other curved surfaces.

The rear end of the main cylinder 4 is fixed to the front surface of the towboy 9, and the master cylinder 2 and the main cylinder 4 are arranged in the engine room. Also, push rod 3 and main cylinder 4 in the driver's cab.
A boot 10 made of an elastic material is provided between the rear end and the rear end.

A passage 4 opened on the side of the assist pressure chamber 4a
A pressure generating means 11 such as electromagnetic means is connected to d. Furthermore, a controller 12 is provided which detects the operation of the brake pedal 1 and outputs an electric signal.The output signal of this controller 12 causes the pressure generating means 11 to operate, thereby increasing the pressure of the hydraulic oil in the assist pressure chamber 4a. An electromagnetic servo brake system is configured to control this. In this embodiment, the controlled pressure in the assist pressure chamber 4a is set to a high pressure higher than atmospheric pressure, but it may also be set to a pressure lower than atmospheric pressure. Furthermore, this invention is not limited to the electromagnetic servo brake system described above, but can be applied to other brake systems having a brake pedal 1, a master cylinder 2, a push rod 3, a main cylinder 4, etc.

The operation of the above embodiment will be described below.

When the brake pedal 1 is depressed from the illustrated state in which the brake pedal 1 is not depressed, the pressure generating means 11 is activated by an output signal from the controller 12, and the pressure of the hydraulic oil in the assist pressure chamber 4a increases. The primary piston 2c is pushed forward by the advancement of the push rod 3 due to the depression of the brake pedal 1 and the increase in the hydraulic pressure in the assist pressure chamber 4a, and the accompanying
The secondary piston 2d is also pushed forward by the pressure increase in the oil chamber 2e, and as a result, the hydraulic oil in the first oil chamber 2e acts on the front wheel brake device 7, and the hydraulic oil in the second oil chamber 2f acts on the rear wheel brake device 8. Each operates. At this time, when the brake pedal 1 is depressed, the shaft 1a moves on an arcuate trajectory centered on the shaft 1b, so the push rod 3 swings up and down by a small angle around the tip of the arcuate portion 3a. However, the support member 5 that supports the push rod 3 is displaced along the concave curved surface 4c due to the rolling of the ball bearing 5d, and the seal member 5b also slides along the concave curved surface 4c, so the push rod 3 operates without prying. Not only this, but also the hydraulic oil at the rear end of the assist pressure chamber 4a is completely sealed.

(Effect of the invention) As described above, in the brake device of this invention, the push rod passes through the support member in the assist pressure chamber to reach the master cylinder, and the inner wall of the main cylinder that forms the support member and the assist pressure chamber. are a convex curved surface and a concave curved surface that correspond to each other, and a sealing member was provided between the two, so
Regardless of the change in angle of the push rod caused by depression of the brake pedal, the support member follows the change, and the sealing of the working fluid can be completely eliminated.
As a result, the length of the main cylinder and push rod adjacent to the master cylinder can be reduced, which in turn reduces the length of the device that protrudes from the engine room into the operator's cabin, allowing effective use of space in the operator's cabin. This has an excellent effect.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view showing an embodiment of this invention. 1... Brake pedal, 2... Master cylinder, 2a... Cylinder body, 2b... Braking hydraulic chamber, 3... Push rod, 4... Main cylinder, 4a... Assist pressure chamber, 4b... Push rod insertion hole, 4c... Concave curved surface, 5... Supporting member, 5a... Convex curved surface, 5b... Seal member.

Claims (1)

[Scope of utility model registration request] A master cylinder having a braking hydraulic pressure chamber, a push rod connected to a brake pedal and transmitting the depression force of the brake pedal to the master cylinder, and an assist pressure chamber formed adjacent to the master cylinder, The chamber is formed with a concave curved surface on the inner wall on the side into which the push rod is inserted, and a support member that is loosely fitted into the assist pressure chamber and supports the push rod is formed with a convex curve corresponding to the concave curve of the inner wall, A brake device for an automobile, characterized in that a sealing member is provided on the concave curved surface and the convex curved surface around the push rod insertion hole of the assist pressure chamber, so that the support member can follow the angular displacement of the push rod.