JPS6085270A - Vacuum pump - Google Patents

Abstract

PURPOSE:To relax the impact of a rocker arm when it collides against a rod part, by resiliently cushioning a sleeve, slidably built in the rod part, to be adapted to a swivelling end part of the rocker arm. CONSTITUTION:A sleeve 23 is slidably fitted in an axial direction to the bottom end side of a rod part 22. A compression spring 24 of small contour is interposed between an outward facing flange part 23a of said sleeve 23 and an outward facing flange part 22b provided in the rod part 22. Then the sleeve 23 is received to be supported to a fork part 31 in a rocker arm 30, urging the rocker arm always in a counter clockwise direction. In this way, impact of the fork part 31 in the rocker arm 30 against the rod part 22 can be relaxed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vacuum pump that is installed in a vehicle such as an automobile and is driven by an engine or the like to apply negative pressure to various negative pressure actuators.

(Prior art) As one type of this type of vacuum pump, an operating piston provided inside the housing body is assembled so as to be able to reciprocate in the axial direction. A negative pressure chamber is formed on one side of the screw part of the pump, and the rod part of the actuating piston is engaged with the swinging end of the rocker arm that swings by rotation of the pump drive shaft, and the actuating piston is The rocker arm 1 is compressed by a compression spring interposed in the housing main body.
1 to the side opposite to the negative pressure chamber against a pushing force of 1, and reciprocating the actuating piston in the axial direction by the rocking action of the rocker arm to generate negative pressure in the negative pressure chamber. There is something configured like this.

Therefore, this type of vacuum pump reduces the biasing force of the compression spring against the working piston by utilizing the fact that the suction force against the working piston increases in accordance with the increase in negative pressure generated in the negative pressure chamber. When the negative pressure exceeds the specified pressure, the operating screw is activated! - The rod part has the function of gradually separating from the swinging end of the rocker arm to reduce its reciprocating stroke, thereby producing the following effects.

(1> Engine power loss when driving the vacuum pump can be reduced.

(2) It is possible to improve durability such as abrasion resistance by reducing the force applied to each component when the vacuum pump is driven, and it is also possible to reduce the size and thickness by reducing stress. It is possible to reduce the weight and cost of the bomb.

(3) If the vacuum pump is a piston-type vacuum pump, the wear of sliding parts such as the cylinder part and piston hand is suppressed1 to improve its durability, and if it is a diaphragm-type vacuum comb bomb, the diaphragm Diafurano reduces the tensile stress and compressive stress that occur in
The durability of the product can be improved.

By the way, in this type of vacuo pump, the rocker arm always swings even in state B where the 0918 part of the operating piston and the swinging end of the IJ rack arm are separated, so the swinging end of the rocker arm There is a problem of repeated collisions with a part of the rod portion of the working piston. i;(l Lee-C, mitigation of impact force at the time of collision is required.

(Purpose of the Invention) The present invention has been made to meet this need, and its main purpose is to provide a vacuum pump of this type with the following: The objective is to reduce the impact force without impairing the above-mentioned advantages (1) to (3).

(Structure of the Invention) In order to achieve the above object, the present invention provides a vacuum pump of this type, in which a sleeve that can come into contact with the swinging end of the l'' lug arm is placed in the rod portion of the working piston in the axial direction. A second compression spring is interposed between the sleeve and the rod portion of the actuating piston to bias the sleeve toward the side opposite to the negative pressure chamber, and the sleeve is attached to the rocker arm so that it can be slid a certain amount. Its structural feature lies in the fact that it elastically abuts against the swinging end of the shaft.

(Operations and Effects of the Invention) As a result, in the present invention, when the negative pressure in the negative pressure chamber increases beyond a predetermined level, the rod portion of the actuating piston is cut into the sleeve and moves in the axial direction to move the actuating piston. Move it to the negative pressure chamber side. During this time, the sleeve is always in contact with the swinging end of the rocker arm due to the second compression spring interposed between the rod part and the sleeve, and the swinging movement of the rocker arm causes the sleeve to move in the axial direction integrally with the swinging end. When sliding toward the negative pressure chamber side, the second compression spring is bent and mixed while sliding. For this reason, the impact force of the sleeve on the J section and the impact force of the swinging end of the rocker arm on the loft section are alleviated.

Since the rocker arm swings around the support shaft in the middle, the swinging end of the rocker arm swings in an arc and axially moves toward the mouth/sword part of the actuating piston. It applies an acting force not only in the direction perpendicular to that direction but also in the orthogonal direction.

However, in the present invention, since the second compression spring is interposed via the sleeve, the second compression spring can be maintained in a stable state even when the rocker arm swings, and the second compression spring The compression spring can always perform its intended buffering function.

(Embodiment) Hereinafter, an embodiment of the present invention will be described based on the drawings. FIG. 1 shows a piston type vacuum pump which is an embodiment of the 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) as two parts in a vehicle.
The operating piston 20 is disposed due to the zero reason. Further, a space formed by the lower housing 11 of the housing body IO and the cylinder head and /\watt bar is provided with a Nihar rocker arm 30, and this rocker arm 30
One end of the cam 42 is in contact with an eccentric cam 42 provided on an A-buffet force shaft 41 of the engine.

The operating piston 20 has a disk-shaped piston part 21 and a rod part 22 as main components, and the lower housing 1
The piston part 21 is airtightly and movably inserted into the cylinder part 12a formed by the cylinder liner 12 press-fitted into the cylinder liner 12, and the lower end of the rod part 22 is attached to the bottom of the lower housing 11 in the axial direction. It is assembled within the lower housing 11 by being slidably supported thereon. The actuating piston 20 is urged downward in the figure by a first compression sublink 17, which will be described later, and its rod portion 22 is supported on a flanged portion 31 that is a swinging end portion of a rocker arm 30.
Further, one end contact portion 32 of the rocker arm lt 30 resiliently contacts the outer periphery of the eccentric cam 42 from the lower portion thereof. As a result, a negative pressure chamber R1 is formed on the negative side of the piston portion 21 of the working piston 20, and this negative pressure chamber R1 is connected to the suction check valve 14 in the suction chamber R2 provided in the upper housing 13.
It communicates intermittently with the atmosphere through the discharge check valve 15 of the piston portion 21.

Therefore, in the actuating piston 20 of this embodiment, the lower end side of the rod portion 22 is formed in the shape of a step 1''1 foot, and the collar 23 is fitted into the small diameter portion 22a so as to be slidable in the axial direction. . This collar 23 is provided with an outward flange portion 2; 3a at its lower end, and this outward flange portion 23a and an outward flange portion 221 provided on the rod portion 22.
A second compression spring 24 with a small diameter is interposed between them. As a result, the collar 23 is received by the fork portion 31 of the rocker arm 30 and abuts against the stepped portion 22c of the rod portion 22,
The second compression spring 24 always urges the rocker arm 30 counterclockwise in the drawing via the collar 23. In addition, the flange portion 22b of the rod portion 22 and the piston portion 21
A cylindrical retainer 2 is inserted between the lower surfaces of the
6 is assembled with a nut 27. The cylindrical portion 26a of the retainer 26 extends downward by a predetermined length, and an outward flange portion 26b is provided at the lower end opening thereof. On the other hand, an inward flange part 12b functioning as a retainer is formed at the lower end of the cylinder liner 12 forming the cylinder part 12a, and the inward flange part 12b and the outward flange part 2Bb of the retainer 26 are opened via the filter 16. A large-diameter first compression sublink 17 is interposed. The first compression spring 17 always pushes the operating piston 2o downward via the retainer 26 to move the stepped portion 22c of the rod portion 22 onto the collar 2.
3, and when the negative pressure in the negative pressure chamber R1 exceeds a predetermined pressure, it is compressed in one direction according to this negative pressure. The filter 1 (+) is made of a porous material such as a wire mesh, and prevents sludge generated in the crankcase and mixed in the lubricating oil from flowing into the cylinder portion 2a.

The vacuum pump configured in this manner is in the state shown in FIG. 1 when not driven, and when the camshaft 41 rotates in the direction of the arrow due to engine drive, the rocker arm 3
0 repeatedly swings vertically about the support shaft 33 due to the action of the eccentric cam 42, and the operating piston 20 moves to the first position.
It is repeatedly slid in the vertical direction by the downward biasing action of the compression spring 17 and the upward pushing action of the rocker arm 3o. During this period, when the working piston 20 moves, the suction check valve 14 closes and the discharge check valve 15 closes.
opens, and the air in the negative pressure chamber R1 is discharged through the discharge check valve 15. In addition, when the operating piston 20 moves downward, negative pressure is generated in the negative pressure chamber R1, and the suction check valve 14 closes at the same time as the discharge check valve 15 closes, creating a negative pressure in the negative pressure chamber R. Pressure is applied to a negative pressure actuator such as a brake booster through the suction chamber R2.

By the way, during this time, the 11 pressure in the negative pressure chamber R1 increases, and the suction force acting on the piston portion 21 of the working piston 20 becomes the first
When the force ↑I of the compression spring 17 is overcome, the first compression spring 17 is compressed upward according to the negative pressure in the negative pressure chamber R1. Therefore, the bottom dead center of the actuating piston 20 moves upward according to the compression amount of the first compression spring 17, that is, the value of the negative pressure in the negative pressure chamber R1, and accordingly and the upper end of the collar 23 are separated.

As a result, when the negative pressure in the negative pressure chamber R1 exceeds a predetermined value,
The force acting on the actuating piston 200 and the rocker arm 30 is reduced. Therefore, wear of each sliding part in the vacuum pump is reduced, and power loss of the engine is reduced.

During this time, in the vacuum pump, the sleeve 23 is in elastic contact with the swinging end 31 of the rocker arm 30 due to the biasing force of the second compression spring 24. Therefore, the sleeve 23 slides in the vertical direction integrally with the swinging end 31 when the rocker arm 30 swings.
- When moving, it slides while bending the compression spring 24.

Therefore, the impact force of the sleeve 23 on the rod portion 22 of the actuating piston 20, that is, the impact force of the swinging end portion 31 of the rocker arm 30 on the mouth portion 22 is alleviated.

In addition, in the vacuum pump, the swinging end 31 of the mouth/lug arm 30 swings in an arc around the support shaft 33, not only in the vertical direction but also in the vertical direction with respect to the rod part 22 of the actuating piston 20. It also applies force in the horizontal direction. However, in this vacuum pump, since the second compression spring 24 is interposed through the sleeve 23, it is difficult to maintain the second compression spring 24 in a stable interposed state even when the rocker arm 30 swings. can. Therefore, the second compression spring 24ζ can exhibit its intended buffering function.

FIG. 2 shows a diaphragm type vacuum pump which is another embodiment of the vacuum pump according to the present invention. Except for this vacuum pump, the operating piston is a diaphragm piston 208, the shape of the housing body 10A due to the adoption of the diaphragm piston 2OA, the location of the discharge check valve 15A, etc. , has substantially the same construction as the vacuum pump of the first embodiment shown in FIG. Therefore, the cuum bomb of the second embodiment has substantially the same effect as the cuum bomb of the first embodiment, except that the durability of the diaphragm 21A constituting the diaphragm piston 2OA is improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a piston-type vacuum 11 pump, which is an embodiment of the vacuum pump according to the present invention, and FIG. 2 is a longitudinal cross-sectional view of a diaphragm-type vacuum pump, which is an embodiment of the vacuum pump. . Description of symbols lO...Housing body, 17...First compression spring, 20.20A...Working piston, 21...Piston part, 21A...Diaphragm, 22φ...Rod part, 23φ... Collar, 24... Second compression spring, 30... Mouth/Nno J arm, R1... Negative pressure chamber. Applicant: Toyota Motor Corporation (and 1 other person) Representative: Patent attorney Teru Hase −

Claims (1)

[Claims] The actuating piston installed inside the housing body is assembled so as to be able to reciprocate in the axial direction, thereby forming a negative pressure chamber on one side of the piston part of the actuating piston, and connecting the rod part of the actuating piston to the pump drive shaft. A compression spring is engaged with the swinging end of the rocker arm that swings due to the rotation of the rocker arm, and the actuating piston is inserted into the housing main body by a compression spring that resists the pushing force of the rocker arm on the side opposite to the negative pressure chamber. In the vacuum pump, the working piston is reciprocated in the axial direction by the swinging action of the rocker arm to generate negative pressure in the negative positive chamber. A sleeve that can come into contact with the swinging end of the rocker arm is glued so that it can slide a predetermined amount in the axial direction.
A second compression spring is interposed between the sleeve and the rod portion of the actuating piston to urge the sleeve toward the side opposite to the negative pressure chamber, so that the sleeve is resiliently pushed against the swinging end of the rocker arm. A vacuum pump characterized by being brought into contact with a target.