JP2518895Y2 - Vacuum booster - Google Patents

Description

[Detailed description of the device]

[0001]

The present invention relates to a vacuum booster,
More specifically, the present invention relates to a vacuum booster with improved responsiveness and return during operation.

[0002]

2. Description of the Related Art A conventional vacuum booster is generally provided at the tip of an operating rod that works in conjunction with a brake pedal, and has a valve plunger slidably fitted in a piston-side member and an annular seat. And a valve member that can come into contact with the rear end of the valve plunger and the annular seat. The valve member first sits on the annular seat as the operating rod is displaced and connects the pressure chambers before and after the piston. After the passage is blocked, the valve mechanism is separated from the rear end of the valve plunger to allow the atmosphere to flow into the pressure chamber on the rear side of the piston. Then, by displacing the operating rod via the brake pedal, the valve mechanism is actuated to generate a differential pressure between the pressure chambers before and after the piston, and the piston is moved by this differential pressure and attached to this piston. Braking an automobile by generating operating pressure on the driven rod on the brake side.

[0003]

However, in the valve mechanism in the conventional vacuum booster, the guide portion of the valve plunger is provided in the passage through which the atmosphere enters and exits when the valve is switched, for example, in the valve body accommodating the valve plunger. Had to be provided as a radial hole on the rear side of the valve or as an axial groove on the inner surface of the valve body around the guide portion. Therefore, conventionally, there has been a problem that the air inflow passage is insufficient and the response time during operation and the return time during piston return are adversely affected.

The present invention has been made to solve the above problems, and an object thereof is to provide a vacuum booster capable of shortening the response time and the return time during operation.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a valve plunger which is provided at the tip of an operating rod which is interlocked with a brake pedal, and is slidably fitted on the piston side, and a rear end of the valve plunger. A valve member that normally abuts, the valve member blocking the passage connecting the pressure chambers in front of and behind the piston with the displacement of the valve plunger, and then separating from the rear end of the valve plunger. A valve mechanism that allows the atmosphere to flow into the pressure chamber through a passage that communicates with the pressure chamber on the rear side of the piston, and the pressure applied to the piston is controlled by the valve mechanism to attach the brake side to the piston side. A vacuum booster for generating an operating pressure on a driven rod, characterized in that a hole for expanding a flow passage of the atmosphere is provided in a part of the valve plunger. It is obtained by achieving the above objects by.

[0006]

According to the present invention, when the brake pedal is operated, the valve member is first displaced so as to be in close contact with the valve plunger to shut off the passage connecting between the pressure chambers in front of and behind the piston. When atmospheric air is introduced into the valve member away from the member, the atmospheric air can flow into the pressure chamber on the rear side of the piston through the passage and the hole of the valve plunger to operate the piston.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 1 is a view showing a tandem type vacuum booster which is an embodiment of the vacuum booster of the present invention.
A front power piston 4 and a rear power piston 5 are arranged in series in a closed shell 3 constituted by a rear shell 2 and a rear shell 2. The inside of the closed shell 3 is divided by a center plate 6 into a front chamber on the front power piston 4 side and a rear chamber on the rear power piston 5 side, and the front chamber is a front diaphragm attached to the back surface of the front power piston 4. 7, pressure chambers A and B
The rear chamber is partitioned into pressure chambers C and D by a rear diaphragm 8 attached to the rear surface of the rear power piston 5.

Reference numeral 9 denotes a valve body arranged in the axial core portion of the hermetic shell 3, and a cylindrical portion 9A containing a valve mechanism 10 described later and a cylindrical portion 9A integrally expanded in diameter and connected. And a large-diameter center body portion 9B that supports the power pistons 4, 5 and the center plate 6 and the like, and is formed concentrically inside the center body portion 9B via an annular groove 9C. It has a tubular hub portion 9D. The front power piston 4 and the front diaphragm 7 each have an inner peripheral portion having a flange portion 9E at the front end of the center body portion 9B and a center body portion 9B.
The rear power piston 5 is sandwiched by an annular member 11 attached to the rear diaphragm 8, and the rear power piston 5 has a stepped portion of the reduced diameter portion 9F near the rear end of the center body portion 9B together with the rear diaphragm 8 and the reduced diameter portion 9F. It is sandwiched by the annular member 12 attached to the. Further, the inner peripheral portion of the center plate 6 is slidable in the axial direction in the center body portion 9B via the seal member 13.

Further, the tubular hub portion 9D has a spherical tip portion 1 at the tip of the operating rod 14 which is interlocked with a brake pedal (not shown).
A valve plunger 15 crimped to 4A is slidably fitted therein, while a driven rod 17 is connected to a front end of the hub portion 9D via a reaction disc 16. Therefore, when the vacuum booster operates, the brake reaction force is transmitted to the brake pedal via the driven rod 17, the reaction disc 16, the valve plunger 15 and the operating rod 14. Reference numeral 18 denotes a key inserted through a radial key groove 9G formed in the vicinity of the front end of the tubular portion 9A of the valve body 9, and prevents the valve plunger 15 from coming off. Further, 19 is the inner surface of the front shell 1 and the driven rod 17
It is a return spring that is elastically mounted between the retainers 20 that are fitted to the rear end of the rear power piston, and constantly urges the front power piston 4 and the rear power piston 5 toward the inoperative position side in the figure.

The center body portion 9B is formed in the annular groove 9C between the center body portion 9B and the hub portion 9D.
A passage 21 is formed so as to pass through the side wall in the axial direction, and the pressure chamber A and the inside of the tubular portion 9A communicate with each other through the passage 21. Further, the pressure chamber C and the passage 21 are provided on the side wall of the reduced diameter portion 9F.
A passage 22 that communicates with the pressure chamber C is formed in the radial direction, and the pressure chamber C and the pressure chamber A communicate with each other via these passages 21 and 22. Further, a passage 23 penetrating a side wall of the tubular portion 9A continuously provided at the rear end of the center body portion 9B is formed behind the key groove 9G. The passage 23 forms a tubular shape. The inside of the portion 9A communicates with the pressure chamber D. Further, the passage 21 is provided on the side wall of the center body portion 9B.
A passage 24 located in the circumferential direction 180 ° is formed along the axial direction. By the passage 24, the pressure chamber B and the pressure chamber D
And are in communication.

The valve mechanism 10 built in the cylindrical portion 9A is constituted by the valve plunger 15, the annular seat 9h at the rear end of the hub portion 9D, and the valve member 25.
The operating rod 14 is inserted through the central hole 25A of the valve 5 with a gap. The valve member 25 is constantly urged toward the valve plunger 15 and the annular seat 9h by a spring 26 elastically mounted on the back surface of the valve member 25. On the other hand, the operating rod 14
Is urged by a spring 27 in a direction to move backward with respect to the valve body 9. Also, valve plunger 15
As shown in FIGS. 1 and 2, has a groove portion 15A with which the key 18 is engaged, and a guide portion 15B formed by continuously expanding the diameter behind the groove portion 15A. This guide part 1
A space between the outer peripheral surface on the rear end side from 5B and the inner peripheral surface of the hub portion 9D serves as a communication passage 28 between the passage 21 and the passage 23. Further, a plurality of (six in this embodiment) holes 15C are formed in the guide portion 15B at equal intervals in the radial direction (see FIGS. 3 and 4), and the communication passage 28 and the key groove 9G are formed by these holes 15C. The pressure chambers B and D communicate with each other.

According to the vacuum booster of the present embodiment described above, when the operating rod 14 is moved leftward in FIG. 1 by the brake pedal during its operation, the valve member 25 first causes the annular portion at the rear end of the hub portion 9D. The passage 21 and the communication passage 28 are closed closely to the seat 9h, and then the rear end of the valve plunger 15 is separated from the valve member 25 to open the communication passage 28 to the atmosphere, so that the atmosphere in the communication passage 28 is released. Inflow. The inflowing air passes through the passage 23 and the six holes 15C, and then the pressure chamber D
It flows into the pressure chamber B through the inside and the passage 24, and the brake is operated as in the conventional case.

Therefore, according to the present embodiment, as a flow passage for the atmospheric air flowing from the central hole 25A of the valve member 25 to the pressure chamber D and the like when the vacuum booster is operated, the conventional passage 2 is used.
In addition to 3, the six holes 15C of the guide portion 15B of the valve plunger 15 are added to expand the flow passage leading to the pressure chamber D, so that the inflow velocity of the atmosphere into the pressure chamber D is higher than in the conventional case. It becomes faster and the response time to the brake operation is shortened, and conversely each piston 4, 5 after releasing the brake operation
The return time is shortened.

In this embodiment, only the case where the passage to the pressure chamber D of the atmosphere is the passage 23 provided on the rear end side of the guide portion 15B of the valve plunger 15 has been described, but as shown in FIG. The passage 23 can be applied to a plurality of passages provided around the guide portion 15B.

Further, the guide portion 15 of the valve plunger 15
The shape of the hole provided in B may be an arc-shaped elongated hole 15C shown in FIG.

In summary, in the vacuum booster of the present invention,
The existing passage 23 is used as a passage for circulating the atmosphere to the pressure chamber.
In addition, if a passage for expanding the air flow passage is separately provided in a part of the valve plunger, they are all included in the present invention.

Needless to say, the present invention can be applied to devices other than the tandem type vacuum booster.

[0018]

As described above, according to the vacuum booster of the present invention, since a hole through which the atmosphere is introduced is separately provided in a part of the valve plunger constituting the valve mechanism, the response time during operation is increased. Also, the return time to the non-operation can be shortened.

[Brief description of drawings]

FIG. 1 is a sectional view showing an entire tandem type vacuum booster which is an embodiment of the vacuum booster of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a valve plunger of the tandem type vacuum booster shown in FIG. 1 taken out.

3 is a front view from the left side of the valve plunger shown in FIG.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a view corresponding to FIG. 4, showing another embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 3 showing a valve plunger of still another embodiment of the present invention.

[Explanation of symbols]

 4 Front Piston 5 Rear Piston 10 Valve Mechanism 14 Operating Rod 15 Valve Plunger 15B Guide 15C Hole 17 Driven Rod 25 Valve Member 28 Communication Passage A to D Pressure Chamber

Claims (1)

(57) [Scope of utility model registration request] 1. A valve plunger, which is provided at the tip of an operating rod that interlocks with a brake pedal and is slidably inserted into the piston side, and a valve member that is normally in contact with the rear end of the valve plunger. The valve member interrupts a passage connecting between the pressure chambers in front of and behind the piston as the valve plunger is displaced, and then separates from the rear end of the valve plunger to the atmosphere in the pressure chamber on the rear side of the piston. In a vacuum booster that controls the pressure applied to the piston by the valve mechanism to generate an operating pressure on the brake-side driven rod mounted on the piston side. A vacuum booster characterized in that a hole for expanding the flow path of the atmosphere is provided in a part of the vacuum booster.