JPH0755526A - Piston moving type fluid device - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost of a piston moving type fluid device by forming pistons and yokes which couple the pistons with each other in simple shapes. CONSTITUTION:In a fluid device which converts the reciprocating motions of orthogonally arranged two pairs of pistons 8A and 8B and 8C and 8D into the rotating motion of a rotating shaft 16 through a cam roller 33 and eccentric cam 19 and makes a fluid sucked from an inlet to flow out from an outlet by switching a change-over valve which integrally rotates with the shaft 16, each pair of pistons 8A and 8B and 8C and 8D and their coupling yokes 3OA and 30B are formed in platy shapes and slits 31 for passing the shaft 16 are formed in the yokes 30a and 30B. In addition, cam rollers 33 are fitted to the upper or lower surfaces of the yokes 30A and 30B.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston reciprocating fluid device used as a flow meter or a pump.

[0002]

2. Description of the Related Art As a fluid device of this type, there is, for example, a four-piston type flow meter provided with two pairs of pistons which are interlocked in pairs. It comprises a body 2 provided with four cylinders 1A, 1B, 1C, 1D arranged on two axes which are orthogonal to each other, as shown in FIGS. 4 and 5. The main body 2 forms the four cylinders and has a communication chamber 3 that communicates with each other.
And an upper lid 5 and a lower lid 6 that cover the upper and lower openings of the casing 4 that communicate with the communication chamber 3, and side lids 7, 7 ... That cover the outer openings of the cylinders.

Pistons 8A, 8B, 8C, and 8D are slidably fitted in the cylinders 1A, 1B, 1C, and 1D, and these pistons are arranged to face each other on the same axis. The pair of pistons 8A and 8B and 8C and 8D are connected by yokes 9A and 9B. Each of the yokes 9A and 9B is composed of a pair of curved left and right arm portions 10 and a connecting portion 11 that connects the pair of arm portions 10, and both ends of the pair of arm portions 10 are provided with corresponding pistons 8A and 8A.
Under the state of being brought into contact with the back surface of B or 8C, 8D, it is fixed to the piston by a bolt 12 inserted from the outer surface side of each piston. Each piston is composed of a piston body 13, a seal member 14 and a retainer 15 arranged on the outer surface side of the piston body 13, and
The bolt 15 is integrated with the piston body 13 by the bolt 12.

A rotary shaft 16 having a communication chamber 3 extending in the vertical direction is rotatably supported on the main body 2 via bearings 17 and 18. An eccentric cam 19 is fixed to the rotary shaft 16 in the communication chamber 3, and each piston 8 is attached to the outer periphery of the eccentric cam 19.
A cam roller 22 rotatably attached using a bolt 21 is in contact with a boss portion 20 projecting from the back surface of A, 8B, 8C, 8D. The yokes 9A and 9B are provided with the eccentric cam 19
The upper and lower positions are extended, and a central portion thereof is curved upward or downward to avoid interference with the eccentric cam 19. Further, the pair of arm members 10 of each yoke 9A, 9B are set such that the center portion thereof is set to a minimum interval allowing insertion of the rotary shaft 16, while both end portions thereof avoid interference with the cam roller 22. Is set wide.

Further, each piston 8A, 8B, 8C, 8D
And the side lid 7 are partitioned as measuring chambers 23A, 23B, 23C and 23D, and the respective measuring chambers 23A and 23B are connected to flow paths 24A and 24B formed at the bottom of the casing 4 (cylinder 1C. 1D side is omitted). The tip of each of the flow paths 24A and 24B is provided on the lower surface of the casing 4 with an inflow port 25 of the cup-shaped lower lid 6.
And the inside of the cup of the lower lid 6 and the outlet 26 of the upper lid 5 through the communication chamber 3. A liquid feeding means (not shown) such as a pump is connected to the inflow port 25 of the lower lid 6, and a liquid supply means (not shown) such as an oil supply nozzle is connected to the outflow port 26 of the upper lid 5.

On the other hand, a cup-shaped switching valve 27 is attached to the lower end of the rotary shaft 16 which extends through the lower wall of the casing 4 and extends into the lower lid 6. On the bottom side of the switching valve 27, an annular spring bearing that is not rotated with respect to the switching valve 27 is provided.
28 is arranged, and a spring (compression spring) 29 for elastically urging the switching valve 27 against the casing 4 is interposed between the spring receiver 27 and the inner bottom surface of the lower lid 6. It is equipped. The switching valve 27 has a hollow portion 27a in which the flow passages 24A and 24B are provided.
By selectively facing one of the measuring chambers, one of the measuring chambers 9B communicates with the inflow port 25 and the other measuring chamber 9A communicates with the outflow port 26.

In the four-piston type flow meter constructed as described above, the fluid pressure-fed from the liquid feeding means is as shown in FIG.
In the state shown in Fig. 2, as shown by the solid line arrow, it enters the inside of the lower lid 6 from the inflow port 25, and further passes through the flow path 24B to one measuring chamber.
Enter 23B. At this time, since the other measuring chamber 23A communicates with the outlet 26, the pressure difference causes a pair of pistons 8A,
8B moves integrally to the left in FIG. 5, and the fluid in the measuring chamber 23A has a flow passage 24A and a cavity 27 of the switching valve 27 as indicated by a dotted arrow.
a, through the communication chamber 3 and discharged from the outlet 26 to the outside. The leftward movement of the pistons 8A, 8B, 8C, 8D causes the rotating shaft 16 to rotate 90 degrees via the eccentric cam 19, and at the same time, the switching valve 27 also rotates 90 degrees. Then, the pair of pistons 8C, 8 in the other opposing cylinders 2C, 2D
D moves in one direction, the fluid in the corresponding measuring chamber is supplied and discharged, and the rotating shaft 16 is rotated by 90 degrees.

Then, the flow path 24A is communicated with the inflow port 25, the flow path 24B is communicated with the outflow port 26, and the pair of pistons 8A and 8B are moved rightward in FIG.
While the fluid flows into A, the fluid in the measuring chamber 23B is discharged to the outside. Then, since the stroke of each pair of pistons is constant, the discharge amount of the fluid per one rotation of the rotary shaft 16 is constant, and therefore the flow rate can be measured by measuring the number of rotations. When the rotary shaft 16 is rotationally driven in this fluid device (flow meter), a certain amount of fluid can be pumped up through the inflow port 25, and thus it can function as a pump. A similar piston type flow meter is disclosed in Japanese Utility Model Publication No. 58-7296.

[0009]

However, according to the above-mentioned conventional piston reciprocating fluid device, the yokes 9A and 9B connecting the pair of pistons to each other have the pair of arm portions 10.
Since it has a curved and complicated shape, it has a problem that its manufacturing is troublesome and an increase in manufacturing cost cannot be avoided. Also, each piston 8A, 8
Boss for attaching the cam roller 22 to B, 8C, 8D
Since 20 must be provided, the shape of the piston becomes complicated, and there is a problem that an increase in manufacturing cost cannot be avoided like the yoke.

The present invention has been made in view of the above problems of the prior art, and provides a piston reciprocating fluid device which has a simple shape of a piston and a yoke for connecting the pistons, and which greatly contributes to a reduction in manufacturing cost. The purpose is to do.

[0011]

In order to achieve the above-mentioned object, the present invention provides an eccentric cam in which a piston, which is connected by a yoke and interlocks with each other, is provided in the main body, and each piston is attached to a rotary shaft. The measuring chambers, which are engaged with each other via a cam roller, are connected to the fluid inlet and outlet through a flow passage, and the flow passage is opened by a switching valve that rotates integrally with the rotary shaft. In the piston reciprocating fluid device configured to selectively switch to either the inlet or the outlet, the yoke is formed in a flat plate shape,
The cam roller is rotatably attached to the lower surface or the upper surface of the yoke.

[0012]

In the piston reciprocating fluid device constructed as described above, since the yoke connecting the pistons is formed in a flat plate shape and the cam roller is attached thereto, not only the yoke shape is simplified but also the piston shape is improved. Since the boss portion for mounting the cam roller can be eliminated, the piston shape can be simplified and the manufacture thereof can be facilitated.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 and FIG. 2 show a first embodiment of a piston reciprocating fluid device according to the present invention.
The present embodiment is configured as the four-piston type flow meter, and here, the same parts as those shown in FIGS. 4 and 5 are designated by the same reference numerals and the description thereof will be omitted. And In the first embodiment, each pair of pistons 8
Yokes 30A and 30B for connecting A and 8B and 8C and 8D
Is formed in a flat plate shape, and a slit 31 that allows the rotation shaft 16 to be inserted therein is provided in the center thereof. This york 30
A and 30B are formed by punching a single plate material, and both end portions are slightly wider than the central portion where the slit 31 is provided. Each yoke 30A, 30B
Is a bolt inserted from the outer surface side of each piston under the condition that the upper and lower positions of the eccentric cam 19 are extended and both ends of the eccentric cam 19 are in contact with the back surfaces of the corresponding pistons 8A, 8B or 8C, 8D. It is fixed to the piston by 32.

On the other hand, the cam roller 33 that contacts the eccentric cam 19
Is rotatably attached to both ends of each of the yokes 30A and 30B using bolts 34. More specifically, the cam roller 33 has one yoke 30 that is on the upper side of the eccentric cam 19.
It is attached to the lower surface of A and is attached to the upper surface of the other yoke 30B which is the lower side with respect to the eccentric cam 19.
Therefore, each cam roller 33 is located on the same plane as the eccentric cam 19.

Before assembling the flowmeter, each yoke is
A yoke assembly in which the cam roller 33 is attached to 30A and 30B using bolts 34 is prepared, and the lower yoke assembly is fixed to the corresponding pistons 8C and 8D with bolts 32 to complete the piston assembly. Then, first, the piston assembly is attached to the cylinder 1 of the main body 2 with the side cover 7 opened.
Then, the rotary shaft 16 to which the eccentric cam 19 is attached is inserted from the upper opening 4a of the casing 4 with the upper lid 5 opened, and the slit 31 of the lower yoke 30B is inserted. It is supported by the lower bearing 18. At this time, the two cam rollers 33 of the lower yoke assembly already assembled
To contact the eccentric cam 19.

Next, the piston 8 is placed in the cylinders 1A and 1B.
Inserting A and 8B, and the upper yoke assembly 36
Is inserted from the upper opening 4a of the casing 4 as shown by the chain double-dashed line. At this time, the rotary shaft is inserted into the slit 31 of the yoke 30A.
The yoke assembly 36 is inserted while inserting 16 and the two cam rollers 33 are brought into contact with the eccentric cam 19. Next, the pistons 8A and 8B are fixed to both ends of the yoke 30A using bolts 32, and then the upper lid 5 and the side lid 7 are attached to the casing 4 to complete the flowmeter.

The operation of the flow meter constructed as described above is the same as that of the conventional flow meter (FIGS. 4 and 5), and the reciprocating motion of each pair of pistons 8A and 8B and 8C and 8D accompanying the supply of fluid. Is converted into rotational movement of the rotary shaft 16 via the cam roller 33 and the eccentric cam 19, and the flow rate can be measured from the number of rotations of the rotary shaft 16. Thus, in the first embodiment, each pair of pistons 8A and 8B and 8C and 8D is used.
Since the yokes 30A and 30B that connect the
The yoke shape becomes simple and its manufacture becomes easy. Moreover, since the cam roller 33 is attached to the yoke,
Boss 20 for mounting the cam roller from each piston
(FIGS. 4 and 5) can be eliminated, the shape of the piston can be simplified, and its manufacture can be facilitated, thus reducing the manufacturing cost as a whole.

FIG. 3 shows a second embodiment of the present invention. The feature of the second embodiment is that the rotating shaft 16
Is formed from a lower shaft member 40 and an upper shaft member 41, a stepped portion 43 having a screw 42 is integrally provided on the upper end of the lower shaft member 40, and a cup having a female screw 44 at the lower end of the upper shaft member 41. The lower and upper shaft members 40, 41 with the male screw 42 and the female screw.
The point is that the eccentric cam 19 is supported in the middle stage of the stepped portion 43 of the lower shaft member 40 by being integrated with the lower shaft member 40 by screwing.

In the second embodiment, the lower piston assembly (8C, 8D, 30B, 33) is inserted into the main body 2 with the side cover 7 opened, and then the rotary shaft having the eccentric cam 19 attached thereto. The lower shaft member 40 of 16 is inserted into the main body 2 while inserting the slit 31 of the yoke 30B, and is supported by the bearing 18. Next, the upper yoke assembly 46 is laterally inserted into the cylinder 1A as indicated by the chain double-dashed line, and the two cam rollers 33 of the yoke 30A are brought into contact with the eccentric cam 19. Then, the upper shaft member 41 of the rotary shaft 16 is inserted from the upper opening 4a of the casing 4, and the cup portion 45 is inserted while inserting the slit 31 of the yoke 30A.
The female screw 44 is screwed into the male screw 42 of the stepped portion 43 of the lower shaft member 40 to complete the rotary shaft 16, and the pistons 8A and 8B are fixed to both ends of the yoke 30A with bolts 32. Book second
According to the embodiment, since the upper yoke assembly 46 can be assembled from the lateral direction, the assemblability is further improved.

[0021]

As described above in detail, according to the piston reciprocating fluid device according to the present invention, the yoke connecting the pistons is formed in a flat plate shape, and the cam roller is attached thereto. Therefore, the shapes of the yoke and the piston are simplified, the manufacture thereof is facilitated, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing an embodiment of a piston reciprocating fluid device according to the present invention.

FIG. 2 is a vertical cross-sectional view of the fluid device shown in FIG.

FIG. 3 is a vertical sectional view showing another embodiment of the present invention.

FIG. 4 is a plan sectional view of a conventional piston reciprocating fluid device.

FIG. 5 is a vertical sectional view of a conventional piston reciprocating fluid device.

[Explanation of symbols]

 2 Main body 8A to C Piston 16 Rotating shaft 19 Cam 24A Flow passage 24B Flow passage 25 Inlet 26 Outlet 27 Switching valve 30A Yoke 30B Yoke 31 Slit 33 Cam roller

Claims (1)

[Claims] 1. A piston is provided inside the main body, the pistons being linked with each other and interlocking with each other. The pistons are engaged with eccentric cams mounted on a rotary shaft through cam rollers, and the pistons are respectively provided outside the pistons. The formed measuring chamber is connected to the fluid inlet and the fluid outlet by the flow passage, and the flow passage is selectively switched to either the fluid inlet or the flow outlet by the switching valve that rotates integrally with the rotating shaft. In the piston reciprocating fluid device, the yoke is formed in a flat plate shape, and the cam roller is rotatably attached to a lower surface or an upper surface of the yoke.