JP3096539B2 - Piston type fluid pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston type fluid pump mounted on a vehicle such as an automobile and driven by an engine or the like to function as a vacuum pump.

[0002]

2. Description of the Related Art As this type of piston type fluid pump,
There is a piston type double-acting vacuum pump used for a brake booster of a diesel engine (for example, Japanese Utility Model Laid-Open No. 4-1).
No. 34678). This vacuum pump has a pump upper chamber and a pump lower chamber formed above and below a working piston, and a seal member fitted in an annular groove provided on the outer periphery of the piston serves as a sliding portion between the piston and the cylinder. Function. Then, a roller provided at the lower end of the piston rod is driven by a cam linked to the vehicle engine, and the piston moves up and down. This vertical movement acts as a negative pressure source for sucking air from the brake booster.

Further, lubricating oil pumped from a hydraulic pump of an engine is supplied to a bearing opening at a lower end of a bearing for vertically moving the piston rod, and the piston rod and the bearing are moved by a negative pressure in a lower chamber of the pump. Is sucked into the lower pump chamber through an oil passage provided between the piston rod and the oil seal (seal ring), and diffuses into the lower pump chamber. The lubricating oil supplied to the bearing opening lubricates between the piston rod and the bearing and between the piston rod and the seal ring in this way, and is finally sucked and diffused into the lower chamber of the pump to form a mist. Lubricating the sliding part between the piston and the cylinder.

[0004]

In the above prior art,
When the lubricating oil discharged from the oil nozzle of the oil supply means is supplied to the bearing opening, the lubricating oil has been supplied to one side of the outer periphery of the piston rod in one direction. This is because the oil supply means is offset from the extension of the axis of the piston rod. Therefore, the supply of lubricating oil to the outer peripheral portion of the piston rod on the side opposite to the side where the oil supply means is located is reduced, and the outer peripheral portion on the opposite side becomes poorly lubricated. There is a problem that the pump performance deteriorates due to wear of the parts. Then, an object of the present invention is to provide a piston type fluid pump which can solve such a problem.

[0005]

In order to achieve the above object, a piston type fluid pump according to the present invention comprises a piston rod.
And a piston fixed to the piston rod, and the piston
A bearing part that slidably supports a ton rod and a bearing part
A bearing opening located on the opposite side to the piston
The provided by a pump negative pressure supplied lubricating oil to the bearing opening from the oil supply means (29) (24)
Piston to lubricate and sucked into the bearing (11) sliding portion
In Bas accumulation pump, in that a oil groove (40) in the inner peripheral portion of the outer peripheral portion or the bearing (11) of the opposite side to the side where the oil supply means (29) is in the piston rod (10) Features.

In the above structure, the oil groove
Instead of (40), the piston rod (10) may be provided with an oil passage (40A) for transmitting lubricating oil to the bearing opening (24a) opposite to the side where the oil supply means (29) is located.

Further, as described above, the oil groove (40) or
Instead of providing the oil passages (40A) individually , an oil groove (40) is formed in the outer peripheral portion of the piston rod (10) or the inner peripheral portion of the bearing (11) on the side opposite to the side where the oil supply means (29) is located. The piston rod (10) may be provided with an oil passage (40A) for transmitting lubricating oil to the bearing opening (24a) opposite to the side where the oil supply means (29) is provided.

[0008]

In the prior art, the supply of lubricating oil was insufficient. In the sliding portion of the bearing (11) opposite to the side where the oil supply means (29) exists, a large amount of mist-like oil was formed by the oil groove (40). Is sucked and the poor lubrication is eliminated. In addition, o
An oil passage (40A) is provided instead of the oil groove (40).
However, the amount of lubricating oil guided to the opposite bearing opening by the oil passage (40A) increases, and poor lubrication of the sliding portion of the opposite bearing (11) is eliminated. In addition,
If the oil groove (40) and the oil passage (40A) are used together
By each of the above-mentioned operations, poor lubrication is further eliminated.

[0009]

1 and 2, a vacuum pump 1 has a lower casing 2 and an upper casing 3 and is fixed to a cylinder head cover 4 of an engine at a lower portion of the lower casing 2. As shown in FIG. 5
Is a cylinder fixed to the lower casing 2, 6 is a piston that moves up and down in the cylinder 5, and has an annular groove 7 on the outer periphery thereof.
Is fitted with an O-ring 8 and a Teflon piston ring 9. Reference numeral 10 denotes a piston rod, which is vertically slidably supported by a bearing 11 provided on the lower casing 2,
Its upper end is fixed to the center of the piston 6.

Reference numeral 12 denotes a Teflon seal ring provided in the lower casing 2 so as to be fitted to the rod 10, and an oil passage 12a is formed in several places on the inner periphery thereof. 1
Reference numeral 3 denotes an O-ring provided around the seal ring 12, which presses the seal ring 12 against the outer periphery of the piston rod 10 by its elasticity, and also seals the seal ring 1 by a temperature change.
Absorb the dimensional change of 2. 14 and 15 are upper and lower pump chambers formed above and below the piston 6, respectively.
Is a pipe fixed to the lower casing 2 and is connected to a brake booster (not shown). Reference numerals 17 and 18 denote suction valves disposed between the pipe 16 and the upper pump chamber 14 and between the pipe 16 and the lower pump chamber 15, respectively. The pump upper chamber 14 and the pump lower chamber 15 are respectively provided with discharge valves 19, 20.
Through the space in the head cover 4.

Reference numeral 21 denotes a pin fixed to the lower end of the piston rod 10, reference numeral 22 denotes a small-diameter roller rotatably fitted to the pin 21, and reference numeral 23 denotes a large-diameter roller fitted to the outer periphery of the small-diameter roller 22. The roller 23 is in contact with a cam 25 formed on a camshaft of the engine. 26 is a flange formed near the lower end of the piston rod 10, 27 is a compression spring disposed between the flange 26 and the lower casing 2, and urges the piston rod 10 downward to cam the large diameter roller 23. 25.

Reference numeral 24 denotes a bearing opening located below the bearing 11, and reference numeral 28 denotes a communication hole provided in the flange 26. Numeral 29 denotes oil supply means, which has oil supply nozzles 29a and 29b for supplying lubricating oil to the outer peripheral surface of the large-diameter roller 23, which is a bearing opening 24 and a pump drive unit. Oil supply means 29
Is disposed to be deviated rightward in the figure from a line extending downward from the axis of the piston rod 10. That is, it is on the right side of the axis of the piston rod 10. A vertically long oil groove 40 is provided on the outer peripheral portion of the piston rod opposite to the right side where the oil supply means 29 is located.

When the cam 25 rotates in conjunction with the engine, the cam 25 drives the large-diameter roller 23 to move the pump rod 10 and the piston 6 up and down. When the piston 6 rises, the air in the upper pump chamber 14 is discharged to the space in the head cover 4 through the discharge valve 19, and the air in the lower pump chamber 15 from the brake booster (not shown) through the pipe 16 and the suction valve 18. Is inhaled. Oil nozzle 2 at the same time
The lubricating oil supplied directly to the bearing opening 24 from the nozzle 9a through the communication hole 28 causes the negative pressure in the pump lower chamber 15 to
The oil is sucked into the lower pump chamber 15 through the gap between the bearing 11 and the piston rod 10 and the oil passage 12a, and diffuses into the lower pump chamber 15. In addition, the presence of the groove 40 increases the suction amount of lubricating oil due to the negative pressure of the pump chamber at the outer peripheral portion on the left side of the piston rod 10 in the drawing, thereby eliminating the lubrication failure on the opposite side.

When the piston 6 is lowered, the pump lower chamber 15
The air inside is discharged into the space inside the head cover 4 via the discharge valve 20, and air is sucked into the upper pump chamber 14 from the brake booster via the pipe 16 and the suction valve 17. or,
The lubricating oil adhering to the vicinity of the cylinder 5 and the piston ring 9 on the lower pump chamber 15 side flows into the upper pump chamber 14 from the lower pump chamber 15 due to the negative pressure of the upper pump chamber 14 and diffuses into the upper pump chamber 14. . The lubricating oil supplied from the oil supply means 29 to the bearing opening 24 is
The oil is sucked into the pump lower chamber 15 via the oil passage 12a of the seal ring 12 through the gap between the cylinder ring 5 and the bearing 11 to lubricate the space between the cylinder 5 and the piston ring 9. at the same time,
Lubricate between the piston rod 10 and the bearing 11 and between the piston rod 10 and the seal ring 12.

Similar effects can be obtained by providing a longitudinally long oil groove in the left inner peripheral portion of the bearing 11 in place of the oil groove 40 in the first embodiment shown in FIGS. Can be

The second embodiment shown in FIGS.
Instead, an oil passage 40A penetrating the piston rod 10 in the left-right direction in the figure is provided, the right end of which is opened toward the right side where the oil supply means 29 is located, and the left end is opened toward the opposite bearing opening 24a. I let it. By doing so, the lubricating oil is guided to the left bearing opening 24a, and poor lubrication of the left bearing sliding portion is eliminated.

FIG. 5 shows a third embodiment in which both the oil groove 40 of the first embodiment and the oil passage 40A passing through the piston rod 10 of the second embodiment are provided. An oil passage 40A communicates with the opening.

In these embodiments, the engine cam 2
Since the rotation direction of 5 is counterclockwise, the maximum bearing load is applied to the bearing sliding portion on the left outer peripheral portion of the piston rod 10 in the drawing. In the present embodiment, the supply of the lubricating oil to the bearing sliding portion that receives the maximum bearing load is increased, so that in this respect too, poor lubrication is eliminated and the pump life is extended.

The piston rod 10 is moved up and down by being driven by the engine cam 25 as described above, but a flange 26 integral with the piston rod 10 is provided with a locking pin (not shown) fixed to the lower casing 2. It is guided so that it does not rotate. This anti-rotation structure is well known.

[0020]

Since the piston type fluid pump of the present invention is constructed as described above, poor lubrication of the bearing sliding portion on the side opposite to the side where the oil supply means (29) is present is eliminated, and the portion thereof is eliminated. Wear can be reduced. Therefore, stable pump performance can be maintained over a long period of time.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1;

FIG. 3 is a longitudinal sectional view of a second embodiment of the present invention.

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is an enlarged view of a main part of a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Piston rod, 11 ... Bearing, 24, 24a ... Bearing opening part, 29 ... Oil supply means, 40 ... Oil groove, 4
0A: Oil passage

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Okano 1-1-1, Kyowacho, Obu City, Aichi Prefecture Inside Aisan Industry Co., Ltd. (72) Inventor Kazuya Ando 1-1-1, Kyowacho, Obu City, Aichi Prefecture No. 1 Aisan Industry Co., Ltd. (72) Inventor Hideo Nagayama 1-1, Kyowa-cho, Obu City, Aichi Prefecture Examiner, Aisan Industry Co., Ltd. Kazuhiro Ozaki (58) Fields surveyed (Int. Cl. ⁷ , (DB name) F04B 37/14 F04B 39/02

Claims (3)

(57) [Claims] A piston rod and a piston rod fixed to said piston rod.
Slidable piston and piston rod
A bearing portion for bearing and the piston with respect to the bearing portion;
And a bearing opening located opposite to lubricate and sucked into the bearing sliding portion lubricating oil supplied to the bearing opening from the oil supply means by a pump vacuum piston
In Shikiba accumulation pump, the outer peripheral portion or the bearing of the piston rod opposite to the side on which the oil supply means is present
A piston type fluid pump characterized in that an oil groove is provided in an inner peripheral portion of the piston type fluid pump. 2. A piston rod and a piston rod.
Slidable piston and piston rod
A bearing portion for bearing and the piston with respect to the bearing portion;
And a bearing opening located opposite to lubricate and sucked into the bearing sliding portion lubricating oil supplied to the bearing opening from the oil supply means by a pump vacuum piston
In Shikiba accumulation pumps, piston-type fluid pump, characterized by comprising an oil passage for communicating said lubricating oil to the bearing opening of the opposite side of the piston rod to the side where the oil supply means is present. 3. A piston rod and a piston rod.
Slidable piston and piston rod
A bearing portion for bearing and the piston with respect to the bearing portion;
And a bearing opening located on the opposite side, the piston vacuum pump to lubricate by suction to the bearing sliding portion lubricating oil supplied to the bearing opening from the oil supply means by the pump vacuum, the oil supply the lubricating oil in the piston oil groove provided on the inner peripheral portion of the outer peripheral portion or the bearing of the rod and the bearing opening on the side opposite to the side where there is an oil supply means opposite to the side where means there piston fluid pump, characterized in that provided on the piston rod an oil passage for transmitting.