JPH03533Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a piston-type vacuum pump that is installed in vehicles such as automobiles and is driven by an engine or the like to apply negative pressure to various negative pressure actuators.

[Prior art]

Generally, in this type of piston type vacuum pump, the piston part of the operating piston is slidably inserted in the axial direction into a cylinder part provided inside the housing body, and a suction check valve is installed on one side of the piston part. A negative pressure chamber equipped with a discharge check valve is formed, and the rod part of the operating piston is engaged with a rocker arm that swings due to rotation of the pump drive shaft, and the suction check valve is provided in the housing body. A suction port of a suction chamber that communicates with the negative pressure chamber through a valve is connected to a negative pressure actuator through a third check valve, and the actuating piston is slid by the swinging action of the rocker arm, and the suction port is connected to the negative pressure actuator through a third check valve. The negative pressure generated in the pressure chamber is applied to the negative pressure actuator through the suction chamber.

In the conventional piston type vacuum pump of this type, however, the sliding part between the inner circumference of the cylinder part 1a of the housing body 1 and the outer circumference of the piston part 2a of the working piston 2 shown in FIG. 5 is lubricated. In order to prevent wear, burnout, etc. of the sliding parts, engine oil or the like supplied by an oil pump or the like driven by the engine is jetted into the housing body 1. The ejected engine oil or the like is sucked into the cylinder portion 1a by the suction effect when the operating piston 2 slides, and adheres to the sliding portion, thereby lubricating the sliding portion.

[Problem that the invention attempts to solve]

By the way, in such a piston type vacuum pump, normally the suction check valve 3a and the discharge check valve 3b open and close alternately, but when the vacuum pump is driven at high speed, the valve bodies of both check valves 3a and 3b open and close. Due to the inertia force of ) may enter the third check valve V through the negative pressure chamber R1 and the suction chamber R2 and deteriorate the valve performance of the third check valve V.

In order to cope with this problem, the present applicants have filed a piston-type vacuum pump in Japanese Patent Application No. 1982-192904, in which a gas-liquid separation means with air permeability is provided in the suction chamber. The present invention aims to solve the above problems more effectively than the vacuum pump.

[Means for solving problems]

In order to deal with this, the present invention provides the piston-type vacuum pump described above, in which one or more shielding plates are disposed in the suction chamber facing the suction port, and a stagnation part is provided in the suction chamber. Its structural feature lies in the formation of a communicating bent passage.

[Functions and effects of the idea]

As a result, in the present invention, the lubricating oil that attempts to enter the third check valve from the negative pressure chamber through the suction check valve and the suction chamber is blocked by the shielding plate and collected in the retention portion, and the third check valve It is possible to prevent lubricating oil from entering the valve side. Furthermore, the lubricating oil accumulated in the suction chamber is recirculated into the negative pressure chamber by air flowing into the negative pressure chamber from the negative pressure actuator side, and is discharged to the outside of the negative pressure chamber through the discharge check valve. Therefore, it is possible to prevent deterioration of the valve performance of the third check valve due to lubricating oil, and
Thereby, the function of the negative pressure actuator can be maintained in a stable state for a long period of time. Further, since the shielding plate is simply provided within the housing body, piping does not become complicated when the vacuum pump is mounted on a vehicle.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a piston type vacuum pump according to the present invention. In this vacuum pump, a housing body 10 is attached to a cylinder head and a head cover (not shown) at one side of the upper part of an engine in a vehicle, and an operating piston 20 is disposed within the housing body 10. A rocker arm 30 is disposed in a space formed by the lower housing 11 constituting the housing body 10, the cylinder head, and the head cover, and one end 31 of this rocker arm 30 is attached to an overhead camshaft 41 of the engine. It is in contact with the eccentric cam 42.

The operating piston 20 has a disk-shaped piston portion 21
The piston part 21 is hermetically and slidably fitted into the cylinder part 11a of the lower housing 11, and the lower end of the rod part 22 is inserted into the cylinder part 11a of the lower housing 11.
It is assembled to the lower housing 11 by being slidably supported in the axial direction at the bottom of the housing. Further, the actuating piston 20 is located at the stepped portion 11b of the lower housing 11.
The fork portion 32, which is the swinging end of the rocker arm 30, is supported by the seat portion 22a provided on the rod portion 22, and one end of the rocker arm 30 is urged upward by a compression spring 12 whose lower end is locked. 31 is brought into elastic contact with the outer periphery of the eccentric cam 42, and a negative pressure chamber R1 is formed on the upper surface side of the piston portion 21. As shown in FIG. 3, this negative pressure chamber R1 communicates intermittently with a suction chamber R2 formed by an upper housing 13 and a cover 14 fixed to its upper surface via a suction check valve 15. It communicates intermittently with a discharge chamber R3 provided in the discharge chamber R3 via a discharge check valve 16. Further, the suction chamber R2 is connected to the negative pressure actuator A via a third check valve V.

As a result, in this vacuum pump, when the camshaft 41 rotates in the direction of the arrow due to the drive of the engine, the rocker arm 30 repeatedly swings vertically about the support shaft 33 due to the action of the eccentric cam 42, and the operating piston 20 repeatedly slides in the vertical direction due to the upward biasing action of the compression spring 12 and the downward pushing action of the rocker arm 30. During this period, when the working piston 20 moves upward, the suction check valve 15 closes and the discharge check valve 16 opens, and the air in the negative pressure chamber R1 is discharged through the discharge chamber R3. Further, when the working piston 20 moves downward, negative pressure is generated in the negative pressure chamber R1, the suction check valve 15 opens, and the discharge check valve 16 closes, so that the negative pressure in the negative pressure chamber R1 is transferred to the suction chamber R2 and the suction port 14a. and third check valve V
Negative pressure is applied to actuator A such as a brake booster through. During this time, engine oil supplied by an oil pump (not shown) driven by the engine is ejected from the ejection hole 42a of the eccentric cam 42 to the lower part of the lower housing 11 to lubricate each sliding part.

Therefore, in this embodiment, a shielding plate 51 is provided within the suction chamber R2. This shielding plate 51
is integrally provided with the cover 14, and forms a reservoir 52 at the bottom facing the suction port 14a of the suction chamber R2, and also serves as a suction check valve 1.
5. A bent passage 53 is formed that communicates the retention portion 52 and the suction port 14a.

Therefore, when the vacuum pump is driven at high speed, the mist of lubricating oil that has entered the negative pressure chamber R1 flows into the suction chamber R2.
Even if the lubricating oil attempts to flow out through the third check valve V side, the lubricating oil is adsorbed to the side wall of the bent passage 53 and the surface of the shielding plate 51 and accumulates in the retention portion 52, and does not enter the third check valve V side. Therefore, the third check valve V is free from swelling of the valve body caused by lubricating oil, adhesion and sticking between the valve body and the valve seat, and a decrease in the valve performance of the third check valve V can be prevented. can. In addition, the lubricating oil accumulated in the accumulation part 52 is transferred to the negative pressure actuator A.
When the atmosphere inside is exhausted again due to the operation of
and is discharged to the atmosphere through the discharge chamber R3.

FIG. 4 shows a modification of the above embodiment. In this modification, three shielding plates 51
a, 51b, and 51c are arranged. Of each shielding plate 51a, 51b, 51c, two shielding plates 5
1a and 51c are integrated with the cover 14 and the remaining 1
The two shielding plates 51b are integrally provided in the upper housing 13, and the two retaining parts 52a, 52b are provided integrally with each other.
and a bent passage 53a. Thereby, the same effect as the above embodiment can be achieved.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an example of the vacuum pump according to the present invention, Fig. 2 is a plan view of the vacuum pump, and Fig. 3 is a partial cross section of the vacuum pump in the direction of the arrow in Fig. 2. FIG. 4 is a partial sectional view corresponding to FIG. 3 showing a modification of the vacuum pump, and FIG. 5 is a longitudinal sectional view showing an example of a conventional vacuum pump. Explanation of symbols, 10...Housing body, 11a
...Cylinder part, 14a...Suction port, 15...
...Suction check valve, 16...Discharge check valve, 20...Working piston, 30...Rocker arm, 51, 51a-51c...Shielding plate, 52,5
2a, 52b... Retention part, 53, 53a... Bent passage, R1... Negative pressure chamber, R2... Suction chamber.

Claims (1)

[Scope of utility model registration request] The piston part of the operating piston is slidably inserted in the cylinder part provided inside the housing body in the axial direction to form a negative pressure chamber equipped with a suction check valve and a discharge check valve on one side of the piston part. At the same time, the rod part of the actuating piston is engaged with a rocker arm that swings by rotation of the pump drive shaft, and the suction valve is connected to the negative pressure chamber through the suction check valve provided in the housing body. The suction port of the chamber is connected to a negative pressure actuator through a third check valve, and the swinging action of the rocker arm causes the actuating piston to slide and the negative pressure generated in the negative pressure chamber to pass through the suction chamber. In the piston-type vacuum pump configured to apply negative pressure to the negative pressure actuator, one or more shielding plates are disposed in the suction chamber facing the suction port, and the suction chamber has a stagnation part and communicates therewith. A piston-type vacuum pump characterized by forming a bent passageway.