JPS61152971A - Radial plunger pump - Google Patents

Abstract

PURPOSE:To reduce rotational loss torque with rotation of a rotor, by making a plunger tip end contact with an inner ring of a guide ring via a spherical rolling element and also making this inner ring contact with an outer ring via a first rolling element. CONSTITUTION:A steel ball 12 or a spherical rolling element is rotatably connected to a tip end of a plunger so as to slide together with radial movements of the plunger 11 without dropping. A guide ring 13 is constituted of an outward outer ring 13a and an inward inner ring 13b, a first rolling element being free of rotation and interposing between these inner and outer rings, namely a steel ball 13c.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a radial plunger pump,
For example, it is effective when used as a pump for supplying hydraulic pressure to a hydraulic device such as a power steering system.

[Conventional technology]

A conventional radial plunger pump has a cylinder that is radially bored in a rotatable rotor, a plurality of plungers installed in this cylinder, and a cylinder that is eccentric to the center of the rotation axis of the rotor and that slides with the tip of the plunger. A variety of plunger shapes have been devised to ensure smooth sliding surfaces between the plunger and the cam ring. For example, a slipper is attached to the tip of the plunger, and the hydraulic pressure inside the cylinder is guided to the sliding surface of the slipper to form a hydrostatic bearing to maintain hydraulic equilibrium.
Some plungers have a roller attached to the tip of the plunger via a shaft to facilitate smooth contact with the cam.

However, the above-mentioned pump equipped with a slipper requires machining to guide the hydraulic pressure, and the efficiency of the pump decreases because it guides the hydraulic pressure inside the cylinder. In addition, with rollers, the plunger receives lateral force (rotational force), so
There is a problem in that separate processing is required to prevent excessive force from acting on the plunger.

[Problem that the invention seeks to solve]

The present invention is unique, and unlike the above pumps, the pump efficiency is high.
The purpose was to obtain a pump that is compact and capable of smooth high-speed operation.

On the other hand, the applicant of this application has a prior art (Japanese Patent Application No. 74411/1983) to achieve the same purpose as above.
Basic principles and examples are disclosed. The present invention is based on the technology of the above-mentioned prior application, and provides a pump with further technical improvements.

In the technology of the prior application, the conventional cam ring is changed to a guide ring consisting of an inner ring, an outer ring, and a rolling element that rotates smoothly between the two, and the tip of the plunger is brought into contact with the inner ring by a spring. did. However, according to the inventor's experimental results, although smooth rotation is obtained at low discharge pressures, a new problem has arisen in that at high discharge pressures, abnormal wear occurs at the contact portion between the plunger tip and the inner ring. This is due to the fact that since the rotor and guide ring are eccentric, some slippage occurs at the abutting portion between the plunger tip and the inner ring.

Therefore, in view of the above points, the present invention aims to provide a pump that is capable of smooth high-speed operation and has excellent durability.

[Means for solving problems]

As a means for solving the above problems, a conventional cam ring is constructed of an inner ring, an outer ring, and a rotatable first rolling element interposed between the two, and the cam ring is rotatably connected to the tip of the plunger. The present invention is characterized in that a spherical rolling element is provided so that the tip of the plunger and the inner ring smoothly come into contact with each other.

[Effect]

According to the above means, the tip of the plunger smoothly contacts the inner ring via the spherical rolling elements, and the inner ring smoothly contacts the outer ring via the first rolling elements, so that the plunger can move smoothly. Become.

〔Example〕

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

As shown in FIGS. 5 and 6, the radial plunger pump includes housings 1a, 1b, and 1c that are fixed together, and the housing 1c has an inlet 2 and an outlet 3 in the center. .

Inside the housings la, lb, and lc, there is a rotor 7 rotatably provided around a bottle 6 having a suction groove 4 and a discharge groove 5. The rotor 7 is rotatably supported by a shaft 8 rotatably supported by the housing 1a. Rotationally driven coaxially and integrally. A bushing 9, which is a sliding member, is fixed to the inner circumferential portion of the rotorf, and rotates smoothly with respect to the bottle 6. The rotor 7 has a plurality of cylinders extending radially from the center, and a radially movable and oil-tight plunger 11 is disposed in each cylinder. A steel ball 12, which is a spherical rolling element, is connected to the tip of the plunger 11 so as to be rotatable and to move without falling off as the plunger 11 moves in the radial direction.

The ball 12 of the plunger 11 is connected to the housing la and the housing 1.
rolls on the inner surface of the guide ring 13 supported by b.

The guide ring 13 is restricted from moving in the axial direction of the rotor by the housings la and 1b, and is supported so as to be movable in the radial direction of the rotor. Guide ring 1
3 is composed of an outer ring 13a on the outside, an inner ring 13b on the inside, and a first rolling element, that is, a steel ball 13c, which is interposed between the inner ring and the outer ring and is rotatable. The outer ring 13b contacts a pair of control pistons 15 having rollers 14 at their tips, and the eccentricity of the rotor 7 and guide ring 13 is controlled by the control pistons 15.

When the rotor 7 rotates in the clockwise direction in FIG. and is sucked into the pump chamber 16. After that, when the rotor 7 rotates half a rotation, the tip of the plunger 11 is pressed by the guide ring 14 and moves inward of the rotor 7, and the tip of the plunger 11 is moved inward to the rotor 7, and the plunger 11 is moved inward to the hydraulic oil pump chamber 16, the hole in the bushing 9, the discharge groove 5 in the bottle 6, and It is discharged under pressure through the discharge port 3.

As shown in an enlarged view in FIG. 1, the rotor 7 houses a plunger 11 having a ball 12 at its tip. At the outer tip of the plunger 11, there is a substantially annular cap 17 that serves as a mounting member to prevent the ball 2 from falling off, and a steel ball pole 12 and a pawl slide provided in a recess 11' bored at the tip. A moving member 18 is provided.

A cylindrical recess 11' larger than the diameter of the ball 12 is formed at the tip of the plunger 11.

Further, as shown in FIG. 2, the outer circumferential surface of the tip of the plunger 11 has a tapered outer circumferential surface whose outer diameter decreases from the tip toward the rotor 7 in order to fit the camp 17.
a is formed. A substantially cylindrical sliding member 18 having a recess on its upper surface having a spherical surface corresponding to the ball 12 or a spherical surface slightly larger than the ball 12 is housed in the recess 11'.

The sliding member 18 is made of a material having a low coefficient of friction, such as polyimide resin.

Further, the sliding member 18 is accommodated in the recess 11 with a predetermined clearance so as to be able to move slightly along the axial direction of the rotor tough (in the left-right direction in FIG. 1).

As shown in FIGS. 2 and 3, the lower end of the cap 17 is
Since it is removably fitted to the tapered outer peripheral surface 11a of the plunger 11, it has a tapered flange portion L7b in which four slits 17a are formed. The upper part of the cap 17 has an opening 17c with an inner diameter smaller than the diameter of the ball 12.
is formed along the inner periphery of the opening 17c,
A sliding surface 17d corresponding to the ball 12 is formed.

This sliding surface 17d is preferably made of a low friction material.

The ball 12 is attached to the sliding member 1 at the tip of the piston 11.
8 and a cap 17, which are rotatably connected to each other.
The ball 12 is exposed from the opening 17c of the cap 17 to the extent that it contacts the inner surface of the inner ring 13b of the guide ring 13. Further, the clearance between the cap 17 and the inner ring 1''3b is sufficient to prevent the cap 17 from coming into contact with the inner ring 13b.
Along the inner peripheral surface of b, ball 1 corresponds to ball 12.
An R-shaped groove 19 in which the ball 2 rolls is formed.

Next, the above operation will be explained. When the rotor 7 rotates, the centrifugal force causes the plunger 11 to move outward toward the guide ring 13. Alternatively, the tip thereof is pressed by the guide ring 13 and moves from the guide ring 13 to the inside of the rotor. At this time, since the plunger 11 and the guide ring are in smooth contact via the ball 12, the ball 12 rolls and becomes smooth. Therefore, the loss torque due to rotation of the rotor is significantly reduced at high discharge pressure, and can be made similar to that at low discharge pressure. In addition, the ball 13c located between the outer ring 13c and the inner ring of the guide ring 13 also rolls as the rotor is rotated, but the rolling speed is reduced by providing the ball 12 at the tip of the plunger 11 according to the technology of the earlier application. The durability of the guide ring 13 is approximately half that of the case where the tip of the plunger 11 is simply in direct contact with the guide ring 13, and the durability of the guide ring 13 is improved.

Further, the plunger 11 attempts to rotate within the R-shaped groove 19 on the inner surface of the guide ring 13, that is, within the same plane, but since the rotor tough has a plurality of radially bored holes and the cylinders have machining errors in the axial direction, they are not exactly the same. Not drilled in plane. Therefore, the tip of the plunger 11 is connected to the radius of the guide ring 13.
It receives unreasonable force from the shaped groove 19. However, the ball 18 provided at the tip of the plunger 11 is housed so as to be able to move slightly within the recess 11' together with the sliding member 18.

Therefore, the ball 18 has an important function of allowing the above-mentioned processing error and preventing the tip of the plunger 11 from receiving excessive force from the guide ring 13.

In the above-described embodiment, the ball 12 is provided by attaching the cap 17 to the tip of the plunger 11. You can also use kudzu. Further, as shown in FIG. 4, by interposing an elastic material 19 between the sliding member 18 and the plunger 11, the ball 12 of the plunger 11 can be connected to the guide ring 1.
It is also possible to adopt a structure that attenuates the force acting on 3 and reduces vibration and noise.

〔Effect of the invention〕

As described above, the tip of the plunger contacts the inner ring of the guide ring via the spherical rolling elements, and the inner ring smoothly contacts the outer ring via the first rolling elements, so abnormal wear does not occur, and It becomes possible to reduce the rotational loss torque that accompanies the rotation of the rotor. Experiments have shown that the loss torque can be significantly reduced especially when the pump discharge pressure is high, and the results show that the loss torque is almost constant regardless of the discharge pressure. Therefore, when used as a pump that discharges fluid such as hydraulic oil at high pressure, there are effects such as improved mechanical efficiency and improved durability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing one embodiment of the present invention, FIG. 2 is an enlarged sectional view of FIG. 1, FIG. 3 is a view taken in the direction of FIG. FIG. 5 is a longitudinal sectional view of the radial plunger pump of the present invention, and FIG. 6 is a sectional view taken along line I-'1 in FIG. 5. l a, l b, l c = housing, 7...
・Rotor. DESCRIPTION OF SYMBOLS 11... Plunger, 11'... Recessed part at the tip of plunger, 12... Steel ball, 13... Guide ring, 13a... Outer ring of guide ring, 13b... Inner ring of guide ring, 13C ...Steel ball of guide ring. 17... Cap, 18... Sliding member, 19...
R-shaped groove of inner ring 13b.

Claims (4)

[Claims] (1) A rotor rotatably supported within a housing,
A plunger is movably housed in a plurality of cylinders radially bored in the rotor, a spherical rolling element is rotatably connected to the tip of the plunger, and an outer ring and an inner ring are supported in the housing. and a first rolling element rotatably interposed between the outer ring and the inner ring, and a guide ring eccentric with respect to the rotor, wherein the spherical rolling element of the plunger is connected to the guide ring. A radial plunger pump, characterized in that it comes into contact with the inner surface of the radial plunger pump. (2) The spherical rolling element is rotatably connected to the tip of the plunger by a mounting member having an opening circle with an inner diameter smaller than the diameter of the rolling element. The radial plunger pump described in item 1. (3) The spherical rolling element is housed in a recess formed at the tip of the plunger together with a sliding member that rotatably supports the spherical rolling element. Radial plunger pump as described in section. (4) The spherical rolling element is in contact with an R-shaped groove formed along the inner surface of the guide ring, and the sliding member is housed in a recess at the tip of the plunger so as to be able to move a small amount. Claim 3 characterized in that
Radial plunger pump as described in section.