JPH0658244A - Fluid pressure pump - Google Patents

Abstract

PURPOSE:To miniaturize the motion conversion part of reciprocation of a piston so as to miniaturize the pump. CONSTITUTION:This fluid pressure pump is provided with cylinders 2 radially projecting on the outer circumference of a body 1, and a center chamber 3 communicating to the cylinders within the body 1. An eccentric cam 6 and a polygonal cam ring 8 journaled rotatably and slidably on the eccentric cam 6 through a bearing 7 are provided in the center chamber 3, and suction valves 13 and discharge valves are alternately opened and closed by sliding motion of the pistons 10 in the respective cylinders 2 in elastical contact with the respective cam faces of the polygonal cam ring 8 through presser springs.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fluid pressure pump for supplying fluid to various hydraulic systems.

[0002]

2. Description of the Related Art An example of a conventional fluid pressure pump is shown in FIGS. The reciprocating pump shown in this figure is applied particularly when the fluid is a low-viscosity liquid such as water. The crankcase 01, the crankshaft 02, the connecting rod 03, the plunger 04, and the plunger seal. 08
, Body 07, suction valve section 010, and discharge valve section 011
And a spring 014 and main members such as a cap 015. Generally, a connecting rod 03 and a plunger 0 are provided.
As shown in FIG. 6, four sets of the suction valve unit 010 and the discharge valve unit 011 constitute a triple plunger pump in which three sets are arranged in the crankshaft direction. This type of pump is configured such that the crankshaft 02 is rotated by an external drive source (electric motor, engine, etc.) to connect the connecting rod 03 and the plunger 04.
Of the suction valve 010
Fluid is sucked from the discharge valve unit 011 and discharged from the suction valve unit 010 when the plunger 04 moves rightward on the paper surface, and discharged when the plunger 04 moves leftward on the paper surface. It has a function of discharging the fluid from the valve portion 011.

Further, as described above, this type of pump usually has three
Since it has two plungers, each plunger is 120 ° while the crankshaft 02 makes one rotation (360 °).
Since the suction and the discharge are repeated at the pitch, the discharge pulsation of the number of plungers 3 × 2 occurs during one rotation of the crankshaft 02. The plunger seal 08 prevents fluid from leaking to the crankcase 01 side from the gap between the body 07 and the plunger 04, and a rubber U packing or the like is used.

[0004]

In the pump having such a structure, since the crank mechanism for converting the rotational movement of the crankshaft 02 into the reciprocating movement of the plunger 04 is provided in the crankcase 01, the entire pump is At present, the size of the crankcase portion in the size is large and the size is large. Also, connecting rod 0
3. Since the plungers 04 are laterally arranged in the crankshaft direction, as shown in FIG. 6, 1 × w as a pump appearance is large.

Therefore, in order to increase the pump discharge amount, it is necessary to increase the plunger area, the plunger stroke, and the number of plungers. There is a problem that the outer dimension l × w becomes large. The present invention was developed in order to address such a problem, and an object of the present invention is to reduce the size of the motion conversion portion for reciprocating piston movement and to reduce the size of the pump.

[0006]

The structure of the present invention for achieving the above object will be described with reference to FIGS. 1 to 4 corresponding to the embodiments. The present invention is a cylinder 2 that radially projects to the outer periphery of a body 1. And a central chamber 3 inside the body 1 connected to the base of the cylinder 2, an eccentric cam 6 rotatably supported in the central chamber 3, and a rotatably slidable bearing on the eccentric cam 6 via a bearing 7. A polygonal cam ring 8 supported, a piston 10 in each of the cylinders 2 elastically contacting each cam surface 8a of the polygonal cam ring 8 via a pressing spring 9, and the piston 10
It is characterized by comprising an intake valve 13 and a discharge valve 15 which are alternately opened and closed by sliding.

[0007]

According to the present invention, the piston is formed by the above-mentioned means.
Since the polygon cam ring supported by the eccentric cam via bearings reciprocates by rotating and sliding, the motion conversion mechanism that converts to reciprocating motion of the piston can be made smaller, and the pump can be downsized. Since the arrangement of is also a radial arrangement that is perpendicular to the outer plane of the polygonal cam ring, the number of pistons can be arranged more than in the conventional three-piece system, so the discharge pulsation during one rotation can be reduced, and A stable pressure can be supplied to the system.

Furthermore, since parts such as pistons and piston packings that need to be repaired or replaced are also arranged in a radial arrangement, maintainability such as easy disassembly and installation from the outer peripheral surface of the pump body is not impaired.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. Reference numeral 1 denotes a pump body, and cylinders 2 are provided on the outer periphery of the body 1 so as to radially project at equal intervals. A center chamber 3 connected to the bases of the cylinders 2 is provided inside the eccentric cam 6, which is eccentrically mounted on a rotating shaft 4 supported in the center of the chamber and a bearing for the eccentric cam 6. A polygonal cam ring 8 which is rotatably and slidably supported via a piston 7, and a cam surface 8a of the polygonal cam ring 8 is a piston slidably inserted into the cylinder 2 via a pressing spring 9. The pistons 10 are provided in the same number as the pistons 10 so as to make elastic contact.

The cylinder 2 facing the upper end of the piston 10
The piston chamber 11 of is divided into left and right, one of which is communicated with an intake port 14 which opens to the side of the body 1 through an intake valve plate 13 which is always closed by a presser spring 12, and the other of which is Similarly, a discharge valve plate 15 that is always closed by a presser spring 12 communicates with a discharge port 16 that opens to the side of the body 1, and the suction port 14 communicates with the central chamber 3 through a communication passage 17. .

Each piston 10 has a spacer 18,
A piston packing composed of packing 19 and auxiliary packing 20 is used for sealing. This piston packing is shown in FIG.
As shown in FIG. 5, the endless ring-shaped packing 19 and the outer peripheral surface are formed into a split type auxiliary packing 20 held by a coil spring 20a, and are formed of a resin material in order to reduce the sliding resistance. In order to easily take it out from the inside of the body 1, the holding spring 9 and the packing holding metal fitting 21 are held together by a plug 22 provided on the outer peripheral surface of the body 1, and the suction valve plate 13 and the discharge valve plate 15 are also held by the body. It is held together with the pressing spring 12 and each valve seat 23 by a plug 24 provided on the outer peripheral surface of the body 1 so as to be easily taken out from the inside of the body 1.

In the embodiment, the case where the number of radial cylinders is 5 is illustrated, but the number of the radial cylinders may be 7 or 9, and the polygonal cam ring 8 has a heptagonal shape or a similar structure. It becomes a hexagon. Further, in the embodiment, the cam chamber 3 formed by the body 1 and the flanges 25 on both end surfaces and the end flange 26 is connected to the suction port 14 by the communication passage 17, and the fluid linked from the piston packing 19 and the auxiliary packing 20 is sucked. The structure for returning to the mouth 14 is adopted. Since the inside of the cam chamber 3 is filled with the working fluid, the bearing of the rotating shaft 4 and the bearing 7 between the eccentric cam 6 and the polygonal cam ring 8 should take into consideration corrosion resistance, wear resistance and low wear force when the working fluid is water. It goes without saying that selected ceramics and engineering plastic materials are selected.

Thus, the axis A of the rotary shaft 4 and the axis B of the eccentric cam 6 are deviated by C, and this eccentric amount C × 2 becomes the reciprocating stroke of the piston 10, and the rotary shaft 4 and the eccentric cam 6 are provided.
The polygonal cam ring 8 slides on the outer peripheral surface of the bearing 7 via the bearing 7 and transmits the reciprocating motion to the piston 10 in accordance with the rotation. The rotation of the eccentric cam 6 and the relative movement of the polygonal cam ring 8 are such that the intake stroke is shown in (a), (b) and (c) of FIG. The polygonal cam ring 8 makes a parallel movement between the top dead center and the bottom dead center, and gives a reciprocating motion to the piston 10. This action is the same for all pistons.
At this time, the piston 10 slides relatively to the left and right in the drawing while being pressed against the flat surface 8a of the polygonal cam ring 8 by the pressing spring 9. Peripheral planes 8a of the polygonal cam ring 8
Since each piston is pressed at right angles to each plane, the polygonal cam ring 8 does not rotate as described above but moves vertically and horizontally.

When the piston 10 in FIG. 3 moves downward in the plane of the drawing, the suction stroke occurs, and the suction valve 13 shown in FIG. 1 pushes back the valve plate pressing spring 12 to suck the fluid from the suction port 14. The discharge stroke is when the piston 10 is pushed upwards, the suction valve plate 13 is closed, and the discharge valve 15 is opened while pressing the valve plate pressing spring 12, and is discharged from the discharge port 16 through the discharge hole discharge communication port. These piston movements and intake valves,
The action of the discharge valve is the same for all five valves.
The five pistons continuously discharge and discharge the fluid through the discharge port 16 while sequentially sucking and discharging the pistons as the eccentric cam 6 rotates. By the way, in the case of five pistons, the eccentric cam 6 discharges at intervals of 72 ° during one rotation (360 °).

[0015]

As described above, in the fluid pressure pump of the present invention, since the rotary motion of the rotary shaft and the eccentric cam is exchanged with the vertical cam motion and the horizontal motion of the polygonal cam ring through the bearings, the conventional pump is used. It is possible to significantly reduce the size compared to a crank mechanism with a large rotary motion → linear motion, and since the pistons are arranged radially in the radial direction centering on the rotation axis, even if the number of pistons is increased, it will be the same as a conventional pump. It does not lead to a significant size increase. The number of pistons is selected to be an odd number such as 5, 7, 9 for the purpose of reducing pulsation, but when the length x of the flat surface portion of the polygonal cam ring, the piston strom (eccentricity) S, and the piston diameter d,
Since x> (S + d), the size of the polygonal cam ring and the number of pistons satisfying this need only be designed, and the pump outer diameter φD and the length 1 are determined from these values.

Further, the pump of the present invention has effects such as easy replacement of the main parts such as piston, packing, presser spring, suction valve and discharge valve.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an explanatory view of the operation of a polygonal cam ring.

FIG. 4 is a perspective view of a piston packing.

FIG. 5 is a cross-sectional view showing a conventional example.

FIG. 6 is a perspective view of FIG.

[Explanation of symbols]

 1 Body 2 Cylinder 3 Center Chamber 6 Eccentric Cam 7 Bearing 8 Polygonal Cam Ring 9 Presser Spring 10 Piston 13 Suction Valve 15 Discharge Valve

Claims (3)

[Claims] 1. A cylinder radially protruding to the outer periphery of a body, a center chamber inside the body connected to the base of the cylinder, an eccentric cam rotatably supported in the center chamber, and a bearing for the eccentric cam. A polygonal cam ring rotatably and slidably supported, a piston in each cylinder elastically contacting each cam surface of the polygonal cam ring via a pressing spring, and an intake that is alternately opened and closed by sliding the piston. A fluid pressure pump comprising a valve and a discharge valve. 2. The fluid according to claim 1, wherein an end wrestling packing made of a resin material and a split type auxiliary packing whose outer peripheral surface is held by a coil spring are provided on the outer circumference of the piston. Pressure pump. 3. The fluid pressure pump according to claim 1, wherein the piston, the suction valve, and the discharge valve are detachably attached via a plug embedded in the outer peripheral surface of the body.