JP2003155973A - Hydraulic pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic pump which efficiently performs a shoe holding function by one member only. SOLUTION: This hydraulic pump includes a case, a shaft, many cylinder members, a piston member, a swash plate member, a shoe, and the cylinder members having a bottom face positioned in the direction of opening part of a channel, respectively. A barrel-shaped part protruding from the bottom face of the cylinder member, a step part formed in a waist part of the shoe, and an elastic shoe holder having one side part inserted into the step part of the shoe and coming into contact with the barrel-shaped part are provided. The elastic shoe holder includes a circular central hole, a spherical face part having the center around the circular central hole, and many plates extended from the spherical face part, and comes into contact with the barrel-shaped part which is inserted into the step part of the shoe through the circular central hole and in which one side part of the elastic shoe holder corresponds to the spherical face part.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hydraulic pump,
More particularly, it relates to a hydraulic pump capable of performing the function of holding a shoe with only one member in a suitable manner.

[0002]

2. Description of the Related Art Generally, a hydraulic pump is used for high-pressure pumping and includes a swash plate member having an inclined surface and a piston member having a shoe. In such a structure, the swash plate member (wobb) member is necessary to properly guide the high pressure pumping action of the entire piston device.
The shoe-holding mechanism is used for this purpose because it must make firm contact with the inclined surface of the le plate member.

FIG. 4 is a sectional view of a hydraulic pump having a wobble plate. This hydraulic pump includes a plurality of fluid passages 52, 54 and a case 58 having a cylindrical groove 56 having a shaft bearing hole 57, and is inserted into the shaft bearing hole 57 of the groove 56 so that the shaft 50 can rotate. It Many cylinder members 6
0 has cylinder holes 62, and the case 5
It is arranged in the groove 56 of 8 and can be rotated by receiving the rotational force of the shaft 50. Furthermore, each of the cylinder members 60
Is the cylinder hole 62 and the fluid passages 52, 54.
It has a passage hole 76 for allowing a fluid to pass therethrough. The piston member 64 is disposed in each of the cylinder members 60 and reciprocates in the cylinder hole 62. The swash plate member 68 is coupled to the case 58 to cover the opening of the groove 56. The swash plate member 68 has a protruding portion 65 forming an inclined surface 66 inclined at a predetermined angle.

The piston member 64 reciprocates in the cylinder hole 62, and moves along the inclined surface 66 of the swash plate member 68 with the rotation of the cylinder member 60, and the piston 70 via the connecting member 74. A shoe 72 connected to the. The connecting member 74 is formed of a ball joint, and the shoe 7
2 is allowed to move freely along the inclined surface of the swash plate member 68.

The shoe holder 78 is arranged around the shoe 72 so that the shoe 72 is in close contact with the swash plate member 68. The pair of collars 80 are positioned within the cylinder member 60 at a constant distance, and the elastic member 82 is elastically supported between the pair of collars 80. The barrel member 86 is inserted between the shaft 50 and the shoe holder 78 so as to support the shoe holder 78 with respect to the shoe 72. The pin member 84 is located between the barrel member 86 and the adjacent collar 80.

In the above hydraulic pump, when an elastic force is applied from the elastic member 82, the pin member 84 causes the swash plate member 68 to move.
The elastic force is transmitted to the barrel member 86 so as to press the shoe holder 78 against the inclined surface 66.

As a result, the shoe 72 of the piston member 64 comes into close contact with the inclined surface 66 of the swash plate member 68 and moves along the inclined surface 66 as the cylinder member 60 rotates. At this time, the piston 70 of the piston member 64 reciprocates in the cylinder hole 62 of the cylinder member 60. In this operation, when the shoe 72 of the piston member 64 moves downward along the inclined surface 66, the fluid flows into the cylinder hole 62 through the fluid inflow passage 52 and the passage hole 76. On the other hand, when the shoe 72 moves upward along the inclined surface 66, the cylinder hole 62
The fluid that has flowed in is discharged through the fluid discharge passage 54 via the passage hole 76. With such a method, a desired hydraulic pressure can be obtained in the hydraulic pump.

[0008]

However, the shoe-holding mechanism has the collar member 80 and the elastic member 8.
2, pin member 84, barrel member 86, shoe holder 7
The number of shoeholding elements, including eight, complicates the structure, lengthens the manufacturing time, increases the manufacturing cost,
Production efficiency deteriorates. It is understood that some of the shoe-holding elements are not necessarily required for such a shoe-holding mechanism.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic pump capable of efficiently performing the shoe-holding function with only one member. Such an object can be achieved by a hydraulic pump having an elastic shoe holder. The hydraulic pump has a number of fluid passages,
And a cylindrical groove having a shaft bearing hole. The shaft may be inserted into the shaft bearing hole of the groove to rotate. The plurality of cylinder members, each having a cylinder hole, are arranged in the groove of the case and can be rotated by receiving the rotational force of the shaft. The piston member is located in each cylinder member and reciprocates inside the cylinder hole as the cylinder member rotates. A swash plate member having an inclined surface is coupled to the case to cover the opening of the groove. Each cylinder member has a bottom surface toward the opening of the groove. The shoe having a waist is fixed to the piston member through the connecting member and contacts the inclined surface of the swash plate member.

On the bottom surface of the cylinder member is a barrel (ba
rrel) shaped portion is provided, and a step portion is provided at the waist of the shoe. The elastic shoe holder is inserted into the step portion of the shoe. The elastic shoe holder has a round center hole, and a plurality of elastic bodies are integrally connected to each other and bent inward around the center hole. Insertion of the elastic shoe holder can be realized through a round center hole. When the elastic shoe holder is inserted into the step portion of the shoe, the elastic body contacts the barrel-shaped portion. The bent portions of the elastic body are formed in a bent shape so as to exert a good elastic effect.

[0011]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a sectional view showing a hydraulic pump having an elastic shoe holder according to a first embodiment of the present invention, and FIGS. 2A to 2C are drawings showing the elastic shoe holder.

As shown in FIG. 1, the hydraulic pump has a large number of fluid passages 8 and 10 and a shaft bearing hole 4.
A case 12 having a cylindrical groove 6 having a groove, and a shaft 12 inserted into the shaft bearing hole 4 of the groove 6 and rotatable. Many cylinder members 14
Each has a cylinder hole 16 and the groove 6 of the case 2
The shaft 2 is arranged at a position where the shaft 2 can be rotated by receiving the rotational force of the shaft 2. Further, each cylinder member 14 has a passage hole 18 for allowing fluid to pass between the cylinder hole 16 and the respective fluid passages 8, 10. The barrel-shaped portion projects from the bottom surface of the cylinder member 14 of the main body. Said barrel-shaped part has a rounded surface, which is referred to below simply as barrel 20 and which faces shoe 24. The barrel 20 performs the same function as the barrel member used in the conventional hydraulic pump. The piston member 32 is located in each cylinder member 14 and reciprocates inside the cylinder hole 16 of the cylinder member 14.

The swash plate member 26 is connected to the case 12 to cover the opening of the groove 6. The swash plate member 26 has an inclined surface 28.
Has an upper portion that forms The piston member 32 is a piston 22 that reciprocates in the cylinder hole 16.
And a shoe 24 fixed to the piston 22 via a connecting member 30, and can move along the inclined surface 28 of the swash plate member 26 as the cylinder member 14 rotates. The connecting member 30 is formed of a ball joint that allows the shoe 24 to move smoothly along the inclined surface 28.

The shoe 24 has a step portion on the waist, which will be simply referred to as a stopper 34 in the following. The elastic shoe holder 36 having a certain elasticity is inserted and fixed in the stopper 34 of the shoe 24. 2A to 2C
As shown in FIG. 3, the elastic shoe holder 36 has a round center hole 38 and is connected to each other to form the center hole 38.
And a plurality of elastic bodies 40 that are bent inwardly around. That is, each elastic body 40 is a parallel double surface extending from the bent portion 44 toward the central hole 38. Further, each elastic body 40 has a hole 42 in the double-faced portion. The free end forming portion side of the elastic body 40 adjacent to the hole 42 is in contact with and fixed to the barrel 20, while the opposite side of the elastic body 40 is fixed to the stopper 34 of the shoe 24.

The elastic force of the elastic shoe holder 36 acting between the shoe 24 and the barrel 20 causes the shoe 24 to firmly contact the inclined surface 28 of the swash plate member 26 and stabilize as the cylinder member 14 rotates. Then slope 28
Move along. The bent portion 44 of the elastic body 40 is formed in a bent shape so as to generate an effective elastic force.

In operation, when the shaft 2 transmits a rotational force to the cylinder member 14, the shoe 24 fixed to the piston 22 via the connecting member 30 moves along the inclined surface 28 of the swash plate member 26. Accordingly, the piston 22 reciprocates in the cylinder hole 16 of the rotating cylinder member 14. When the shoe 24 moves downward along the inclined surface 28, the fluid flows into the cylinder hole 16 through the fluid inflow passage 8 and the passage hole 18. On the other hand, when the shoe 24 moves upward along the inclined surface 28, the fluid flowing into the cylinder hole 16 is discharged through the fluid discharge passage 10 via the passage hole 18.

3A through 3C are views showing an elastic shoe holder of a hydraulic pump according to a second embodiment of the present invention. In this embodiment, the entire components of the hydraulic pump other than the elastic shoe holder are the same as those in the first embodiment.

As shown in FIGS. 3A and 3B, the elastic shoe holder 49 has a round center hole 45 and a spherical portion 46 centered around the center hole 45.
And a plurality of plates 48 extending from the spherical portion 46. The spherical portion 46 has a predetermined curvature so as to come into contact with the barrel 20 of the cylinder member 14. With such a structure, the upper and lower diameters of the spherical portion 46 are naturally different, and the desired elasticity can be obtained by the elastic shoe holder 49. As described above, the hydraulic pump of the present invention can perform the function of holding the shoe only by the elastic shoe holder which is a single member, by a proper method. As a result, manufacturing time is shortened, and economical manufacturing cost and high production efficiency can be obtained.

[0019]

The present invention has been described in detail with reference to the above specific embodiments, but for a person having ordinary skill in the art, the book as described in the appended claims. Various changes and substitutions are possible without departing from the technical idea of the invention.

[Brief description of drawings]

FIG. 1 is a sectional view of a hydraulic pump having an elastic shoe holder according to a first embodiment of the present invention.

FIG. 2A is a perspective view of the elastic shoe holder shown in FIG. (B) A front view of the elastic shoe holder shown in FIG. 1. (C) A plan view of the elastic shoe holder shown in FIG. 1.

FIG. 3A is a perspective view of an elastic shoe holder of a hydraulic pump according to a second embodiment of the present invention. 3B is a plan view of the elastic shoe holder shown in FIG. (C) A front view of the elastic shoe holder shown in FIG.

FIG. 4 is a cross-sectional view of a conventional hydraulic pump.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Park John-Keor             Republic of Korea 689-800 Ulsan-City             Ulju-ku Eonyang-Eupbang             Keon-ri 1023-51 Hyundai Apa             No. 105-303 F-term (reference) 3H070 BB04 CC31 CC35 DD13                 3H071 AA01 BB01 CC31 CC34 DD89

Claims (2)

[Claims] 1. A case having a cylindrical groove having a plurality of fluid passages and a shaft bearing hole, a shaft rotatably inserted into the shaft bearing hole of the groove, and a groove of the case having cylinder holes respectively. A plurality of cylinder members arranged to rotate when receiving the rotational force of the shaft, a piston member positioned in each of the cylinder members so as to reciprocate in a cylinder hole of the cylinder member, and the groove. A swash plate member that is coupled to the case so as to cover the opening of the swash plate member, and a shoe that has a waist portion and that is in contact with the swash plate member swash plate member and is fixed to the piston member through a connecting member, In the hydraulic pump, each of the cylinder members has a bottom surface located in the direction of the opening of the groove. An elastic shoe holder having a barrel-shaped portion protruding from a bottom surface of the cylinder member, a step portion formed on a waist portion of the shoe, and one side portion inserted into the step portion of the shoe and contacting the barrel-shaped portion. The elastic shoe holder includes a circular center hole, a spherical portion having a center around the circular center hole, and a plurality of plates extending from the spherical portion, the circular center hole A hydraulic pump in which one side of the elastic shoe holder is inserted into the stepped portion of the shoe through a barrel-shaped portion corresponding to the spherical portion. 2. The hydraulic pump according to claim 1, wherein the spherical portion has a constant curvature, and upper and lower portions have different diameters.