JPS63156865U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a vertical side view showing an embodiment of the present invention;
2 and 3 are enlarged views of the parts shown by arrows in FIG. 1, and FIG. 4 is an enlarged sectional view showing another embodiment of the present invention, and corresponds to FIG. 2. A ₁ , A ₂ ...first and second front chambers, B ₁ , B ₂
...First and second rear chambers, Bo...Vacuum booster, _S1 , _S2 ...Front, rear space, V...Switching valve, 1...Shell body, 7...Partition member, ₈₁ , 8 ₂
...Front and rear pistons, 10...Cylinder body, 22 ₁ ...
...Front bearing tube, 24 ₁ ...Bearing member, 24b...
Projection portion, 27 ₁ , 27 ₂ ... Removal prevention stepped portion, 28 ...
...Seal groove, 30...Seal member, 30a...Inner circumference lip.

Claims (1)

[Scope of utility model registration request] The shell includes a partition member that partitions the interior of the shell into a front space and a rear space, a front piston that divides the front space into a first front chamber and a first rear chamber, and a front piston that divides the rear space into a second front space. A cylindrical body housing a switching valve is provided in a rear piston that is partitioned into a front chamber and a second rear chamber by penetrating the partition member, the first and second front chambers are connected to a negative pressure source, and the switching valve is connected to a negative pressure source. The valve has a function of switching the first and second rear chambers to a communication side with the first and second front chambers or a communication side with the atmosphere, and is provided on the partition member so as to surround the cylindrical body. An annular bearing member that is inserted from one end of the front bearing cylinder and slidably supports the cylinder, and an annular seal member that brings the lip into close contact with the outer peripheral surface of the cylinder. In the tandem vacuum booster, a protrusion protruding from the front bearing cylinder and surrounding the cylinder body is provided at the front end of the bearing member in the insertion direction, and a retaining ring attached to the outer peripheral surface of the protrusion; At least a portion of the front bearing cylinder is clamped by a retaining step formed on the bearing member so as to face the retaining ring, and the sealing member is provided in the bearing member with an opening on its inner circumferential surface. A tandem type vacuum booster characterized by forming a seal groove for attaching.