JPH04119363U - radial piston pump - Google Patents

Abstract

(57) [Summary] [Purpose] By reducing the force generated at the contact area between the cylinder hole 22 and the piston 24 due to the moment generated in the piston 24, wear is suppressed as much as possible, and the lubrication performance and cooling of sliding parts are improved. To provide a radial piston pump that has improved performance and can prevent the accumulation of deteriorating substances in fuel. [Structure] Lubrication grooves 24, 31, and 41 are formed in the upper and lower parts of the pistons 23, 30, and 40, respectively. The existing fuel can improve the lubricity, and the moment can be received in parts other than the lubrication grooves 24, 31, 41, so that the sliding of the piston where the lubrication grooves 24, 31, 41 are not formed can be improved. The moving parts make it possible to maintain oil tightness.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention applies to radial piston pumps, and is especially designed to handle low viscosity fuel. The present invention relates to a radial piston pump suitable for pressure feeding.

0002

[Conventional technology]

Traditionally, radial piston pumps rely on the rotation of an eccentric cam on the pump shaft. Fuel is sucked in and discharged by making the piston move up and down, etc. be. This radial piston pump 1 will be explained below based on FIGS. 5 to 7. do. FIG. 5 is a sectional view of the main parts of the radial piston pump 1, and shows the radial piston pump 1. The pump 1 includes a fixed cylinder 2, an eccentric cam 4 provided on a pump shaft 3, and a fixed cylinder. The cylinder 2 has a piston 6 that reciprocates in cylinder holes 5 formed at equal angular intervals. do. Note that the length of the sliding support portion 5A of the cylinder hole 5 that slidingly supports the piston 6 is L. shall be.

0003 The fixed cylinder 2 has a suction port 7 and a discharge port that communicate with the cylinder hole 5. form 8. The piston 6 slides into contact with the eccentric cam 4, and its reciprocating movement causes these Fuel is taken in and discharged from the suction port 7 and the discharge port 8. In addition, the intake valve and a discharge valve (both not shown). Also, piston 6 A pressurizing chamber 9 is formed in. In other words, while the eccentric cam 4 makes one rotation of 360 degrees, the top dead end of the piston 6 The 180 degrees from the point to the bottom dead center is the suction process, and the remaining 180 degrees is the pumping process. It is.

0004 In this configuration, especially as shown in FIG. 6, the eccentric cam 4 and the piston 6 The contact point draws a circle with a diameter H between the top dead center and bottom dead center of the piston 6. Furthermore, in the first half of 90 degrees during the pumping process due to the rise of the piston 6, the contact point P is Since the piston 6 moves to the left from its center line, the piston 6 has a During 4, a moment acts to tilt it clockwise. Therefore, the piston Wear occurs between the cylinder hole 6 and the cylinder hole 5, particularly at the A portion and the B portion.

[0005] Also, in the latter half of 90 degrees, the contact point P shifts to the right from the center line of the piston 6. Since the piston 6 moves in the opposite direction, a moment acts on the piston 6 to tilt it counterclockwise. . Therefore, between the piston 6 and the cylinder hole 5, there are particularly C portion and D portion. wear occurs.

[0006] In other words, the moment acting on the piston 6 when the contact point P swings from side to side Due to this, the inner wall of the cylinder hole 5 and the piston 6 are There is a problem that metal contact occurs at the upper and lower parts, and wear occurs at this contact area. Ru. Moreover, if impurities such as fuel deterioration products accumulate on the contact area, the piston will There is a problem in that the operation of the ton 6 is hindered.

[0007] As shown in FIG. 7, in the conventional radial piston pump 1, the piston 6 There is one in which a plurality of mutually independent circumferential grooves 10 are formed in the upper and lower parts of the cylinder. The fuel accumulated in the circumferential groove 10 is intended to perform a lubrication function. This also applies to the rotary cylinder type plunger pump according to Utility Model Application No. 1-103777. Such a configuration is disclosed.

[0008] However, the degree of communication between the circumferential groove 10 and the outside of the piston 6 is low. Therefore, it is possible to suppress the wear caused by the tilting of the piston 6 due to the above-mentioned moment. It is difficult to prevent the deterioration from occurring and the accumulation of deterioration products.

[0009]

[Problem that the idea aims to solve] This invention was developed in consideration of the above problems, and it It is possible to reduce the force generated at the contact area between the cylinder hole and the piston due to the moment caused by the This minimizes wear and improves the lubrication and cooling performance of sliding parts. Provides a radial piston pump that can reduce fuel consumption and prevent the accumulation of deteriorating substances in the fuel. The task is to do so.

0010

[Means to solve the problem]

In other words, the present invention provides a fuel intake port, a fuel discharge port, and these ports. A cylinder such as a fixed cylinder having a cylinder hole formed to communicate with the cylinder; A piston is installed in this cylinder hole so that it can reciprocate, and this piston is reciprocated. It has an eccentric cam on the pump shaft, which pumps the fuel by the reciprocating movement of the piston. Radial piston ports that inhale and discharge from the above suction port and discharge port, respectively. a sliding support portion of the cylinder hole that slidingly supports the piston. It is formed long by a length corresponding to the amount of movement from the top dead center to the bottom dead center of the piston, The piston is formed to be longer than the sliding support part, and the piston is made longer than the sliding support part. from the upper and lower ends of the piston to the upper and lower circumferential surfaces of the piston. at least above the piston toward the part where it slides into the inside of the cylinder hole. Lubrication grooves are provided over the above length corresponding to the amount of movement from dead center to bottom dead center. This is a radial piston pump characterized by the following:

[0011]

[Effect]

In the radial piston pump according to the present invention, the upper and lower parts of the piston are Since a lubrication groove is formed in each part, the lubrication groove corresponds to at least the amount of movement of the piston. Good lubricity can be achieved by the fuel existing in the long lubrication groove. In both cases, it is possible to receive moments in areas other than this lubrication groove. , the sliding part of the piston does not form a lubrication groove, making it possible to maintain oil tightness. Wear.

0012

【Example】 Next, a radial piston pump 20 according to an embodiment of the present invention is shown in FIGS. This will be explained based on FIG. However, in the following explanation, the same as Fig. 5 to Fig. 7 will be used. The same reference numerals are given to the parts, and detailed description thereof will be omitted. FIG. 1 is a sectional view of the main parts of the radial piston pump 20, and shows the radial piston pump 20. The pump 20 includes a fixed cylinder 21 and a cylinder hole 22 of the fixed cylinder 21. It has a piston 23 that slides back and forth.

[0013] The length of the sliding support portion 22A of the cylinder hole 22 in the fixed cylinder 21 is , the length of the sliding support portion 5A of the cylinder hole 5 in the conventional radial piston pump 1 It corresponds to the amount of movement of the piston 23 from the top dead center to the bottom dead center than the distance L (Fig. 5). Design it to be longer by length H. Furthermore, the piston 23 is also aligned with the cylinder hole 21 so that the piston 23 is not the same as the conventional piston 6. Form this for longer.

[0014] FIG. 2 is a perspective view of this piston 23, showing the part protruding from the cylinder hole 21. A longitudinal lubrication groove 24 is formed on the circumferential surface symmetrically with respect to the center. As shown in FIG. 1, the length E of this lubrication groove 24 is and from the lower end toward the part where the piston 23 slides inside the cylinder hole 22. , the length must be greater than or equal to the amount of movement H from the top dead center of the piston 23 to the bottom dead center. is desirable.

[0015] Furthermore, the lubrication groove 24 at the upper part of the piston 23 and that at the lower part communicate with each other. shall not be permitted. Therefore, the piston 23 has an upper lubricating portion 23A and a lower lubricating portion 23A. This consists of a lubricating part 23B and an intermediate sliding part 23C between these parts. That will happen.

[0016] In such a configuration, the upper lubrication portion 23A and the lower lubrication portion 23B The lubrication groove 24 in the piston 23 and cylinder hole 21 prevents sliding parts such as Enables sufficient lubrication and eliminates the problem of fuel deterioration substances adhering to the sliding parts. No problem occurs. Furthermore, seizure of the sliding portion is less likely to occur.

[0017] Furthermore, the lubrication grooves 24 of the upper lubrication portion 23A and the lower lubrication portion 23B The lubrication groove 24, which is symmetrical and receives the above-mentioned moment from other parts than the fuel Since the piston 23 receives pressure from the piston 23, it is possible to prevent the piston 23 from collapsing. In addition, ensure the same oil tightness as before in the intermediate sliding portion 23C. I can do it.

[0018] In the present invention, the shape and number of the lubrication grooves are arbitrary. For example, FIG. 3 is a perspective view of a piston 30 according to another example. 30, a rectangular lubricating groove 31 that is relatively easy to process is formed on the piston 30. It is formed on the circumferential surface of the upper part and the lower part.

[0019] FIG. 4 is a perspective view showing a piston 40 according to still another example, and shows the outside of the piston 40. A single spiral lubrication groove 41 that can communicate with the upper and lower parts of the piston 40 They are formed on the circumferential surface of each. Since the lubrication groove 41 is a single groove, The effect of discharging degraded products is good.

[0020]

[Effect of the idea]

As described above, according to the present invention, by lengthening the cylinder hole and piston, By forming lubrication grooves on the upper and lower circumferential surfaces of this elongated part, This allows for moment generation while ensuring lubrication performance, cooling performance, and oil tightness. It is possible to suppress the accumulation of deteriorating substances and to generate pump function without causing wear. be able to demonstrate

[0021]

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a radial piston pump 20 according to an embodiment of the present invention.

FIG. 2 is a perspective view of the piston 23 in the same example.

FIG. 3 is a perspective view of a piston 30 according to another example of the same.

FIG. 4 is a perspective view of a piston 40 according to another example of the same.

FIG. 5 is a sectional view of a main part of a conventional radial piston pump 1.

FIG. 6 is a diagram illustrating the locus of a contact point P between the eccentric cam 4 and the piston 6 in the same embodiment.

[Fig. 7] Circumferential groove 1 formed at the end of the piston 6 in the same figure.
0 is an explanatory diagram.

[Explanation of symbols]

1 Radial piston pump 2 Fixed cylinder 3 Pump shaft 4 Eccentric cam 5 Cylinder hole 5A Sliding support portion of cylinder hole 5 6 Piston 7 Suction port 8 Discharge port 9 Pressurizing chamber 10 Circumferential groove 20 Radial piston pump 21 Fixed cylinder 22 Cylinder hole 22A Sliding support portion 23 of cylinder hole 22 Piston 23A Upper lubricating portion 23B of piston 23 Lower lubricating portion 23C of piston 23 Middle sliding portion 24 of piston 23 Lubricating groove 30 Piston 31 Lubricating groove 40 Piston 41 Lubrication groove H Amount of movement of pistons 6 and 23 from top dead center to bottom dead center L Length of sliding support portion 5A of cylinder hole 5 E Length of lubrication groove 24

Claims (1)

[Scope of utility model registration request] Claim 1: A cylinder having a fuel intake port and a fuel discharge port, and a cylinder hole formed to communicate with these ports; a piston disposed in the cylinder hole so as to be reciprocating; a radial piston pump having an eccentric cam of a pump shaft to be moved, and sucking and discharging the fuel from the suction port and the discharge port respectively by reciprocating movement of the piston, the cylinder slidingly supporting the piston; The sliding support portion of the hole is formed to be longer by a length corresponding to the amount of movement from the top dead center to the bottom dead center of the piston, and the piston is formed longer than the sliding support portion, and the upper portion of the piston is formed to be longer than the sliding support portion. and a lower circumferential surface, from the upper and lower ends of the piston toward the portion where the piston slides inside the cylinder hole, at least for the amount of movement from the top dead center to the bottom dead center of the piston. A radial piston pump characterized in that lubrication grooves are formed over corresponding lengths.