JP2011106347A - Ball plunger pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce contact surface pressure and friction on a contact portion between a ball and a cam face part. <P>SOLUTION: A vertical cross-section of abutting surfaces 5a, 5b of a cam face member 5 has two curves. Cross-sectional curves of the abutting surfaces 5a, 5b are two arcs with a radius R larger than the radius r of a ball 10. The curvature of these curves is larger than the curvature of a spherical surface of the ball 10. Since a recess of the cam face member 5 is configured with the two abutting surfaces 5a, 5b with a curvature larger than that of the spherical surface of the ball 10, the ball 10, freely moving in a cylinder 9 corresponding to the rotational movement of a rotor 4, comes in contact (abuts) with the abutting surfaces 5a, 5b of the cam face member 5 at two points B1, B2. This reduces contact surface pressure on each contact point in the abutting surfaces 5a, 5b of the cam face member 5 and friction between the abutting surfaces 5a, 5b of the cam face member 5 and the ball 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a radial rotary (rotary) pump, and more particularly to a ball plunger pump that is suitable for low-viscosity liquids such as gasoline and uses a plurality of balls as pistons.

  2. Description of the Related Art As a fuel pump (hydraulic pump) for automobiles, a ball plunger pump that is excellent in durability and can realize power saving and has a simple structure is known (for example, see Patent Document 1).

  In a ball plunger pump, a plurality of cylinders that are substantially radially drilled are provided in a rotor, and a ball is placed in each cylinder so that the cylinder can move and rotate in the axial direction of the cylinder. Has been inserted. In order to restrict the outward movement of the ball in the cylinder axis direction, a ring-shaped cam face member is provided on the outer periphery of the rotor.

  The ball plunger pump disclosed in Patent Literature 1 improves the pump efficiency by reducing the wear of the ball and cylinder part by improving the contact state between the ball of the ball plunger pump and the cam face member.

JP-A-2-161175

  However, in the ball plunger pump disclosed in Patent Document 1, since the contact portion between the ball and the cam face portion is a one-point contact, there is a problem that the contact surface pressure increases and the friction increases. is there.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a ball plunger pump capable of reducing contact surface pressure and friction at a contact portion between a ball and a cam face portion.

  In order to solve the above problems, a ball plunger pump (1) of the present invention rotates around a valve shaft (2) having a suction port (11a) and a discharge port (12a) and the valve shaft (2). A rotor (4), a plurality of cylinders (9) drilled substantially radially in the rotor (4), and a cylinder (9) in each cylinder (9) of the plurality of cylinders (9); A plurality of balls (10) inserted so as to be able to move and rotate in the cylinder axis direction, and a ring shape that is positioned on the outer periphery of the plurality of balls (10) and restricts the movement of the plurality of balls (10) A ball plunger pump (1) having a cam face member (5), the ball revolving motion of which is regulated by the cam face member (5) with respect to the axis of the valve shaft (2). 5) The cross section (5a, 5b) perpendicular to the axial direction of the valve shaft (2) at the portion in contact with the plurality of balls (10) has two curves (5a) having a larger curvature than the spherical surface of the ball (10). 5b).

  According to the ball plunger pump of the present invention, the contact surface of the cam face member with the ball is composed of two curves having a curvature larger than the spherical surface of the ball. The contact surface of the face member comes into contact (contact) at two points. Thereby, the contact surface pressure of the contact surface of the cam face member with respect to each contact can be reduced, and the friction between the contact surface of the cam face member and the ball can be reduced. Therefore, friction loss can be reduced, and wear of the contact surfaces of the ball and the cam face member can be reduced.

  In the ball plunger pump of the present invention, the curve (5a, 5b) may be an arc having a radius (R) larger than the radius (r) of the ball (10). With such a configuration, for example, a mold for creating a contact surface of the cam face member can be easily prepared.

  In the ball plunger pump of the present invention, the ratio (R / r) of the radius (R) of the arc (5a, 5b) to the radius (r) of the ball (10) may be 1.04 to 1.12. In this way, by setting the ratio of the radii within a predetermined range, the contact surface of the cam face member and the ball can be reliably brought into contact with each other at two points.

  A predetermined clearance (α) is provided between a portion of the cam face member (5) where the two portions (5a, 5b) contacting the plurality of balls (10) are joined and the ball (10). That's fine. Thereby, the ball and the contact portion of the cam face member can be brought into contact with each other more reliably at two points.

  The reference numerals in the parentheses described above exemplify corresponding constituent elements in the embodiments described later for reference. Reference numerals such as the radii of the respective parts described in parentheses above exemplify the corresponding radii and the like in the embodiments described later for reference.

  According to the present invention, the contact between the ball of the ball plunger pump and the cam face member is a two-point contact, so that the contact surface pressure of the contact surface of the cam face member with respect to each contact is reduced and the cam face member Friction between the contact surface and the ball can be reduced. Further, since the contact surface pressure can be reduced, the wear of the contact portion of the contact surface of the ball and the cam face member can be reduced, thereby improving the durability of the components of the ball plunger pump. Can do.

It is sectional drawing from two directions of the ball plunger pump of this invention. It is a figure which shows the contact state of the ball | bowl with respect to a cam face member and a cylinder. FIG. 3 is an enlarged view of a region X portion in FIG.

  Hereinafter, preferred embodiments of a ball plunger pump of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows a cross-sectional view of a ball plunger pump 1 according to the present invention, and FIG. 1 (a) is a cross-sectional view taken on a horizontal surface in the axial direction of the valve shaft 2 (that is, an arrow in FIG. 1 (b)). 1A-1A partial cross-sectional view), and FIG. 1B is a partial cross-sectional view taken along the line 1B-1B in FIG. The ball plunger pump 1 is driven from the outside by a motor or the like (not shown), and supplies low-viscosity fuel (fluid) such as gasoline or light oil to a combustion chamber (piston) of an engine (not shown).

  As shown in FIGS. 1A and 1B, in the ball plunger pump 1, a ring-shaped cam face member (also referred to as a stator ring) 5 is fixedly provided on the inner surface of the housing 3. . The cam face member 5 is provided eccentrically with respect to the axis of the valve shaft (also called pintle) 2. The valve shaft 2 is provided integrally with the housing 3.

  Inside the cam face member 5, a rotor 4 having a plurality of cylinders 9 with a plurality of balls (eight in this example) drilled radially in the periphery thereof rotates relative to the cam face member 5. It is provided as possible. As shown in FIG. 1 (b), the cam face member 5 has a recess (restraint) for restricting (guiding) the movement of the ball 10 in the outer circumferential direction of the rotor 4 (revolution movement of the ball) on its inner circumferential surface. Contact surfaces 5a, 5b) are provided. Details of the recess will be described later.

  The rotor 4 is pivotally supported on the housing 3 via a plurality of bearings 8 and is rotationally driven by a drive shaft 7. The drive shaft 7 is connected to a motor or the like (not shown). A suction passage 11 and a discharge passage 12 that are in communication with the outside are provided in the valve shaft 2. Each of the passages 11 and 12 is opened on the cylindrical surface of the valve shaft 2 through the suction port 11a and the discharge port 12a. The valve shaft 2 is in a fixed state despite the rotor 4 being rotated. Therefore, the suction port 11a and the discharge port 12a in the valve shaft 2 are repeatedly communicated / blocked with any of the plurality of cylinders 9 according to the rotation of the rotor 4.

  The ball 10 is provided in each cylinder 9, and is inserted so that the cylinder 9 can move and rotate in the cylinder axial direction (radial direction from the center of the rotor 4). A pump chamber defined by the cylinder 9 and the ball 10 communicates with the suction port 11a to suck in the fuel, and the ball 10 moves into the cylinder 9 as the rotor 4 rotates to compress the fuel. The compressed fuel is discharged in communication with the discharge port 12a.

  The valve shaft 2 and the rotor 4 are fitted to each other so that the rotor 4 is relatively rotatable with respect to the fixed valve shaft 2, but the leakage of fuel (fluid) can be suppressed to a minimum. It has become. An oil seal 6 is provided near the opening for the drive shaft 7 of the housing 3 so that fuel does not leak from the rotor 4.

  As shown in FIG. 1B, variable adjustment screws 13 are provided on the left and right side surfaces of the cam face member 5. In this ball plunger pump 1, the position of the cam face member 5 can be adjusted relative to the position of the rotor 4 by the variable adjustment screw 13.

  Next, the contact state between the cam face member 5 and the ball 10 will be described. FIG. 2 is a view showing a contact state of the ball 10 with the cam face member 5 and the cylinder 9. FIG. 2A shows the rotor 4 (the cylinder 9 and the ball 10 in the rotor 4 are also shown in FIG. 2 (b) is a partial sectional view taken along the line 2B-2B in FIG. 2 (a), and the left side in FIG. 2 (a) is shown in FIG. 2 (b). ). FIG. 3 is an enlarged view of a region X in FIG.

  As shown in FIGS. 2B and 3, the ball 10 is restricted from moving in the revolving motion of the rotor 4 by coming into contact with the recess of the cam face member 5. As shown in FIG. 3, the concave portion is composed of two contact surfaces 5a and 5b. In the cross section perpendicular to the axial direction of the valve shaft 2, the contact surfaces 5a and 5b are shown as two curves. In the ball plunger pump 1 of the present embodiment, the curvature of this curve is larger than the curvature of the spherical surface of the ball 10. As described above, since the concave portion of the cam face member 5 is composed of the two contact surfaces 5a and 5b having a larger curvature than the spherical surface of the ball 10, the inside of the cylinder 9 can be freely moved according to the rotational movement of the rotor 4. The moving ball 10 comes into contact (contact) with the contact surfaces 5a and 5b of the cam face member 5 at two points B1 and B2. Thereby, the contact surface pressure with respect to each contact B1 and B2 of the contact surfaces 5a and 5b of the cam face member 5 can be reduced. Further, the friction between the contact surfaces 5a and 5b of the cam face member 5 and the ball 10 can be reduced. Therefore, friction loss can be reduced, and wear of the contact surfaces 5a and 5b of the ball 10 and the cam face member 5 can be reduced, and the components of the ball plunger pump 1 (particularly, the ball 10 and the cam face). The durability of the member 5) can be improved.

  Here, in the ball plunger pump 1 of the present embodiment, the cross sections of the contact surfaces 5 a and 5 b are two arcs having a radius R larger than the radius r of the ball 10. By adopting such a configuration, for example, a mold for creating the contact surfaces 5a and 5b of the cam face member 5 can be easily prepared.

  As shown in FIG. 3, the arc having the radius R has centers A1 and A2, respectively, and the radius R corresponds to the line segment A1-B1 and the line segment A2-B2. These line segments pass through a position D closer to the center of the rotor 4 than the center a of the ball 10 on the center line b of the ball 10 when the ball 10 is in contact with the contact surfaces 5a and 5b. Yes, an angle θ is formed with respect to the upper end of the ball 10, that is, the point where the contact surface 5a and the contact surface 5b are in contact with each other. In this manner, the contact surfaces 5a and 5b are symmetrical with respect to the surface in the vertical direction of FIG. Thus, a large contact surface pressure is not applied to only one of the two contact surfaces 5a and 5b.

  Further, as shown in FIG. 3, a certain clearance α is provided between the ball 10 and the contact portion C of the contact surfaces 5 a and 5 b of the cam face member 5. Thus, by providing the constant clearance α, the ball 10 and the contact surfaces 5a and 5b of the cam face member 5 can be brought into contact with each other more reliably at two points.

  Here, in the ball plunger pump 1 of the present embodiment, the ratio R / r of the radius R of the arc of the contact surfaces 5a, 5b to the radius r of the ball 10 is preferably 1.04 to 1.12. In this way, by setting the radius ratio R / r within a predetermined range, the contact surfaces 5a and 5b of the cam face member 5 and the ball 10 can be reliably brought into contact with each other at two points. In other words, when the radius ratio R / r is smaller than 1.04, particularly when the radius ratio R / r is a value close to 1, the ball 10 has the entire spherical surface of the ball 10 as in the prior art. Therefore, the contact with the contact surfaces 5a and 5b of the cam face member 5 or the contact with the contact surfaces 5a and 5b of the cam face member 5 is increased. End up. On the other hand, when the radius ratio R / r is larger than 1.12, the ball 10 and the contact surfaces 5a and 5b of the cam face member 5 can be reliably brought into contact with each other at two points. As a result, the durability of the ball plunger pump 1 is deteriorated.

  In contrast, by configuring the cam face member 5 as described above, friction loss between the ball 10 and the contact surfaces 5a and 5b can be reduced, and the contact between the ball 10 and the cam face member 5 can be reduced. The wear of the surfaces 5a and 5b can be reduced, and the durability of the components of the ball plunger pump 1 (particularly, the ball 10 and the cam face member 5) can be improved.

  As described above, according to the ball plunger pump 1 of the present invention, the valve shaft 2 having the suction port 11 a and the discharge port 12 a, the rotor 4 rotating around the valve shaft 2, and substantially radial in the rotor 4. A plurality of cylinders 9 pierced in the cylinder 9, a plurality of balls 10 which are inserted in the cylinders 9 of the plurality of cylinders 9 so as to be able to move and rotate in the cylinder axial direction, A ring-shaped cam face member 5 is provided on the outer periphery of the ball 10 to restrict the movement of the plurality of balls 10, and the ball revolving motion with respect to the axis of the valve shaft 2 is regulated by the cam face member 5. In the ball plunger pump 1, the axial direction of the valve shaft 2 of the portions (contact surfaces 5 a, 5 b) that contact the plurality of balls 10 of the cam face member 5. Vertical cross section was constructed to consist of two curves 5a, 5b having a larger curvature than the spherical ball 10. As described above, the contact surfaces 5a and 5b of the cam face member 5 with the ball 10 are composed of the two curves 5a and 5b having a larger curvature than the spherical surface of the ball 10, so that the cam face member 5 freely moves in the cylinder 9. The ball 10 comes into contact (contact) with the contact surfaces 5a and 5b of the cam face member 5 at two points. Thereby, the contact surface pressure of the contact surfaces 5a and 5b of the cam face member 5 with respect to the contacts B1 and B2 is reduced, and the friction between the contact surfaces 5a and 5b of the cam face member 5 and the ball 10 is reduced. Can do. Therefore, friction loss can be reduced, and wear of the contact surfaces 5a and 5b of the ball 10 and the cam face member 5 can be reduced, and the components of the ball plunger pump 1 (particularly, the ball 10 and the cam face). The durability of the member 5) can be improved.

  In the ball plunger pump 1 of the present invention, the curves 5 a and 5 b may be arcs having a radius R larger than the radius r of the ball 10. By adopting such a configuration, for example, a mold for creating the contact surfaces 5a and 5b of the cam face member 5 can be easily prepared.

  In the ball plunger pump 1 of the present invention, the ratio R / r of the radius R of the arc of the contact surfaces 5a, 5b to the radius r of the ball 10 may be 1.04 to 1.12. In this way, by setting the radius ratio R / r within a predetermined range, the contact surfaces 5a and 5b of the cam face member 5 and the ball 10 can be reliably brought into contact with each other at two points. Thus, as described above, friction loss can be reduced and wear of the contact surfaces 5a and 5b of the ball 10 and the cam face member 5 can be reduced. The durability of the ball 10 and the cam face member 5) can be improved.

  In the ball plunger pump 1 of the present invention, a predetermined clearance α is provided between the ball 10 and the portion C where the two contact surfaces 5 a and 5 b that contact the plurality of balls 10 of the cam face member 5 are joined. It only has to be. Thereby, the ball 10 and the contact portions 5a and 5b of the cam face member 5 can be brought into contact with each other more reliably at two points.

  The embodiments of the ball plunger pump of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to these configurations, and is described in the claims, the specification, and the drawings. Various modifications are possible within the scope of the technical idea. In addition, even if it has a shape, structure, or function that is not directly described in the specification and drawings, it is within the scope of the technical idea of the present invention as long as it has the effects and advantages of the present invention. That is, each part which comprises a ball plunger pump can be substituted with the thing of the arbitrary structures which can exhibit the same function. Moreover, arbitrary components may be added.

  In the above-described embodiment, the ball plunger pump 1 has been described by taking an example of a non-equilibrium pump in which the shape of the cam face member 5 is eccentric with respect to the rotor 4. The cam face member is not limited to the ball plunger pump, and can be applied to any shape of the ball plunger pump.

DESCRIPTION OF SYMBOLS 1 Ball plunger pump 2 Valve shaft 3 Housing 4 Rotor 5 Cam face member 5a, 5b Contact surface 9 Cylinder 10 Ball 11 Each passage 11 Suction passage 11a Suction port 12 Discharge passage 12a Discharge port 13 Variable adjustment screw

Claims (4)

A valve shaft having a suction port and a discharge port;
A rotor rotating about the valve shaft;
A plurality of cylinders drilled substantially radially in the rotor;
A plurality of balls inserted in each cylinder of the plurality of cylinders so as to be able to move and rotate in the cylinder axial direction of the cylinders;
A ring-shaped cam face member that is located on the outer periphery of the plurality of balls and regulates the movement of the plurality of balls;
A ball plunger pump in which a ball revolving motion based on the axis of the valve shaft is regulated by the cam face member,
The ball plunger pump according to claim 1, wherein a cross section perpendicular to the axial direction of the valve shaft of a portion of the cam face member that comes into contact with the plurality of balls comprises two curves having a curvature larger than a spherical surface of the ball.   The ball plunger pump according to claim 1, wherein the curved line is an arc having a radius larger than a radius of the ball.   3. The ball plunger pump according to claim 2, wherein a ratio of the radius of the arc to the radius of the ball is 1.04 to 1.12.   The predetermined clearance is provided between the part to which two parts which contact | abut with the said some ball | bowl of the said cam face member are joined, and the said ball | bowl. Ball plunger pump as described.

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