JP2005201220A - Liquid-pressure rotating machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid pressure rotating machinery capable of being obtained for excellent resistance to seizing at a contact part of a cylinder inlet with a piston rod member of a piston, enabling the miniaturization and the high-speed rotation. <P>SOLUTION: Liquid pressure rotating machinery is provided with a casing 1, a rotary shaft 2 rotatably supported with the casing 1, a cylinder block 5 synchronously rotating to the rotary shaft 2, and a plurality of pistons 7 slidably inserted in respective cylinders 6 of the cylinder block 5. The piston rod member 7b of the pistons 7 is integrally formed with a cylinder inside surface contact part 7c, which is located at a deeper side from the cylinder block 5 than this piston rod part 7b and contacts the inside surface of the cylinder 6. Piston rings 8, 9 are provided near the cylinder inside surface contact part 7c, and a copper alloy material part 12 is provided at an inlet 6a of the cylinders 6, on which the piston rod part 7b of the piston 7 slides. The other piston rod member 7b is made of ferrous material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hydraulic rotating machine that is provided in a construction machine or the like and forms an oblique axis type axial pump motor.

  As this type of prior art, there is one disclosed in Patent Document 1, for example. This prior art includes a casing, a rotating shaft that is rotatably supported by the casing, a cylinder block that rotates in synchronization with the rotating shaft, and a plurality of pistons that are slidably inserted into the cylinders of the cylinder block. It has. These pistons are integrally formed with a piston rod portion formed in a tapered shape and a cylinder inner surface contact portion that is located on the inner side of the cylinder block with respect to the piston rod portion and contacts the cylinder inner surface. Further, a piston ring is provided in the vicinity of the above-described cylinder inner surface contact portion.

Therefore, in order to suppress wear with the piston ring, consideration is given to increasing the surface hardness of the cylinder sliding surface, which is a portion where the piston ring of the cylinder contacts. That is, each of the cylinder block and the piston is formed of an iron-based material, and surface treatment for ensuring strength is performed on the cylinder sliding surface and the piston surface.
Japanese Patent Publication No.59-5794

  Nowadays, there is a demand for a hydraulic rotating machine that is smaller and capable of high-speed rotation. In the above-described prior art, when trying to achieve higher speed rotation, the contact portion between the cylinder inlet and the piston rod portion of the piston has a smaller piston diameter than the cylinder diameter, and has a high surface. Since the piston slides with pressure, the situation is very severe in terms of seizure resistance. That is, in the prior art, when trying to perform higher speed rotation, both the cylinder and the piston are made of the same type of iron-based material, so there is a concern that seizure resistance may deteriorate, and as a hydraulic rotating machine, It is difficult to ensure reliability.

  The present invention has been made from the above-described state of the art, and its purpose is to ensure excellent seizure resistance at the contact portion between the inlet portion of the cylinder and the piston rod portion of the piston, and to achieve downsizing and high-speed rotation. The object is to provide a hydraulic rotating machine that can be realized.

  In order to achieve the above object, the present invention provides a casing, a rotating shaft that is rotatably supported by the casing, a cylinder block that rotates synchronously with the rotating shaft, and is slidable within each cylinder of the cylinder block. The piston rod portions of these pistons and the cylinder inner surface contact portion that is located on the back side of the cylinder block and contacts the inner surface of the cylinder are integrated with each other. In the hydraulic rotating machine having a piston ring in the vicinity of the cylinder inner surface contact portion, an inlet portion of the cylinder in which the piston rod portion of the piston is in sliding contact, and the piston in sliding contact with the inlet portion One of the bar portions is provided with a copper alloy material portion, and the other is formed of an iron-based material.

  The present invention configured as described above includes a copper alloy material portion on one of the inlet portion of the cylinder and the piston rod portion of the piston, and the other is made of an iron-based material. That is, the contact portion between the cylinder inlet and the piston rod portion is set to a combination of different metals. Thereby, it is possible to ensure excellent seizure resistance at the above-described contact portion when the piston slides, and to realize downsizing and high-speed rotation.

  Further, the present invention is the above invention, wherein the copper alloy material portion is provided in the inlet portion of the cylinder, and the copper alloy material portion is a copper alloy material containing Cu-Sn as a main component or Cu-Zn as a main component. It is characterized by casting a copper alloy material.

  According to the present invention, in the above invention, the cylinder block is made of an iron-based material, and the cylinder block is subjected to nitriding after casting of the copper alloy material forming the copper alloy material portion. Yes.

  Further, the present invention is the above invention, wherein the copper alloy material portion is provided in the inlet portion of the cylinder, and the copper alloy material portion is made of a copper alloy material bushing mainly composed of Cu-Sn, or Cu-Zn. It is characterized by comprising a bush of a copper alloy material as a main component.

  According to the present invention, in the above invention, the cylinder block is made of an iron-based material that is subjected to nitriding treatment.

  Further, the present invention is the above invention, wherein the copper alloy material portion is provided in the piston rod portion of the piston, and the copper alloy material portion is mainly composed of a copper alloy material mainly composed of Cu-Sn or Cu-Zn. It is characterized by casting a copper alloy material as a component.

  According to the present invention, in the above invention, the piston is made of an iron-based material, and the piston is subjected to nitriding after casting of the copper alloy material forming the copper alloy material portion.

  Further, the present invention is characterized in that in the above invention, the cylinder inner surface contact portion is provided with another copper alloy material portion.

  Further, the present invention is characterized in that, in the above invention, the piston is subjected to nitriding after casting of a copper alloy material forming the another copper alloy material portion.

  In the present invention, the contact portion between the cylinder inlet portion and the piston rod portion of the piston can be made of a combination of different metals, thereby ensuring excellent seizure resistance at the contact portion, which has been conventionally desired. Therefore, a highly reliable hydraulic rotating machine can be obtained.

  The best mode for carrying out a hydraulic rotating machine according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a first embodiment of a hydraulic rotating machine according to the present invention, and FIG. 2 is a cross-sectional view showing a cylinder block constituting a main part of the first embodiment shown in FIG.

  The first embodiment is provided in a construction machine such as a hydraulic excavator. The basic configuration thereof is as shown in FIG. 1, and a casing 1 that forms an outer shell, and a rotating shaft that is rotatably supported by the casing 1. 2 are provided. A drive disk 4 having a plurality of concave spherical surfaces 3 formed on the outer peripheral portion of the end surface and a cylinder block that rotates synchronously with the rotary shaft 2 at the tip of the rotary shaft 2, that is, the right portion of the rotary shaft 2 shown in FIG. And 5. A plurality of cylinders 6 are formed in the cylinder block 5 along the circumferential direction, and pistons 7 are slidably inserted into these cylinders 6. The above-described cylinder block 5 rotates with the center shaft 10 connected to the drive disk 4 as the rotation axis. The center shaft 10 is pressed against the drive disk 4 by a spring 11.

  The piston 7 described above has a spherical portion 7a that is slidably coupled to the concave spherical surface 3 of the drive disk 4 at its end. Also, a piston rod portion 7b formed in a tapered shape and a cylinder inner surface contact portion 7c that is located on the inner side of the cylinder block 5 and contacts the inner surface of the cylinder 6 from the piston rod portion 7b are integrally formed. Yes. For example, two piston rings 8 and 9 are fitted in the vicinity of the cylinder inner surface contact portion 7c.

  In the present invention having such a basic configuration, in particular, either one of the inlet portion 6a of the cylinder 6 in which the piston rod portion 7b of the piston 7 is in sliding contact and the piston rod portion 7b in sliding contact with the inlet portion 6a is provided with a copper alloy material. And the other is made of an iron-based material.

  In the first embodiment shown in FIGS. 1 and 2, for example, as shown in FIG. 2, the cylinder block 5 is formed of an iron-based material, and the inlet portion 6 a of the cylinder 6 included in the cylinder block 5 is a copper alloy material portion 12. It is formed by. The copper alloy material portion 12 is formed by casting, for example, a copper alloy material mainly containing Cu-Sn or a copper alloy material mainly containing Cu-Zn.

  Further, the cylinder block 5 is subjected to nitriding treatment after the above-described copper alloy material forming the copper alloy material portion 12 is cast as described above. The piston 7 described above is made of an iron-based material and is subjected to nitriding treatment. That is, unlike the inlet portion 6a of the cylinder 6, the piston rod portion 7b is made of an iron-based material.

  1st Embodiment comprised in this way is equipped with the copper alloy material part 12 in the inlet part 6a of the cylinder 6 of the cylinder block 5, and the piston rod part 7b of the piston 7 consists of ferrous materials. That is, the contact portion between the inlet portion 6a of the cylinder 6 and the piston rod portion 7b is set to a combination of different metals. Thereby, when the piston 7 slides at high speed, excellent seizure resistance at the contact portion between the inlet portion 6a and the piston rod portion 7b can be ensured, and downsizing and high speed rotation can be realized. Therefore, a highly reliable hydraulic rotating machine can be obtained.

  FIG. 3 is a cross-sectional view showing a cylinder block constituting the main part of the second embodiment of the present invention. In the second embodiment, a copper alloy material portion is provided in the inlet portion 6a of the cylinder 6 of the cylinder block 5, and the copper alloy material portion is, for example, a copper alloy material bush 13 mainly composed of Cu-Sn, or The bush 13 is made of a copper alloy material mainly composed of Cu—Zn. The bush 13 is fitted to the inlet portion 6a of the cylinder 6 by press fitting or shrink fitting. Other configurations are the same as those of the first embodiment described above.

  Also in the second embodiment configured as described above, the contact portion between the inlet portion 6a of the cylinder 6 and the piston rod portion 7b is set to a combination of dissimilar metals, so that the same effect as the first embodiment described above is obtained. Is obtained.

  FIG. 4 is a cross-sectional view showing a piston constituting the main part of the third embodiment of the present invention. In the third embodiment, the piston 7 is made of an iron-based material, and a copper alloy material portion 14 is formed on the piston rod portion 7b of the piston 7. The copper alloy material portion 14 is made of, for example, Cu-Sn. It is formed by casting a copper alloy material containing a main component or a copper alloy material containing Cu-Zn as a main component. The piston 7 is subjected to nitriding after the casting of the copper alloy material forming the copper alloy material portion 14.

  The cylinder block 5 is made of an iron-based material and is subjected to nitriding treatment. Accordingly, unlike the piston rod portion 7b of the piston 7, the inlet portion 6a of the cylinder 6 is also made of an iron-based material. Other configurations are the same as those of the first embodiment described above.

  3rd Embodiment comprised in this way is provided with the copper alloy material part 14 in the piston rod part 7b of the piston 6, and the inlet part 6a of the cylinder 6 of the cylinder block 5 consists of ferrous materials. That is, in the third embodiment, as in the first embodiment, the contact portion between the inlet 6a of the cylinder 6 and the piston rod portion 7b is set to a combination of dissimilar metals. The same effect as the form can be obtained.

  FIG. 5 is a cross-sectional view showing a piston constituting the main part of the fourth embodiment of the present invention. In the fourth embodiment, another copper alloy material portion 15 is also formed in the cylinder inner surface contact portion 7 c of the piston 7. The other copper alloy material portion 15 is also made of, for example, a copper alloy material mainly containing Cu-Sn or a copper alloy material mainly containing Cu-Zn.

  Another copper alloy material portion 15 is cast and formed in the piston 7 made of an iron-based material together with the copper alloy material portion 14 formed in the piston rod portion 7b. The piston 7 is subjected to nitriding after the casting of the copper alloy material portion 14 and another copper alloy material portion 15. Other configurations are the same as those of the third embodiment described above.

  In the fourth embodiment configured as described above, the contact portion between the inlet portion 6a of the cylinder 6 and the piston rod portion 7b is set to a combination of dissimilar metals. Therefore, the same effect as the first embodiment described above is obtained. Is obtained.

  In particular, in the fourth embodiment, another contact portion between the cylinder inner surface contact portion 7c of the piston 7 and the inner surface of the cylinder 6 is also set to a combination of different metals. Excellent seizure resistance can be secured, and a more reliable hydraulic rotating machine can be obtained.

It is sectional drawing which shows 1st Embodiment of the hydraulic rotating machine of this invention. It is sectional drawing which shows the cylinder block which comprises the principal part of 1st Embodiment shown in FIG. It is sectional drawing which shows the cylinder block which comprises the principal part of 2nd Embodiment of this invention. It is sectional drawing which shows the piston which comprises the principal part of 3rd Embodiment of this invention. It is sectional drawing which shows the piston which comprises the principal part of 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 2 Rotating shaft 3 Concave spherical surface 4 Drive disk 5 Cylinder block 6 Cylinder 6a Inlet part 7 Piston 7a Spherical part 7b Piston rod part 7c Cylinder inner surface contact part 8 Piston ring 9 Piston ring 10 Center shaft 11 Spring 12 Copper alloy material part 13 Bush (Copper alloy material part)
14 Copper alloy material part 15 Another copper alloy material part

Claims (9)

A casing, a rotating shaft that is rotatably supported by the casing, a cylinder block that rotates in synchronization with the rotating shaft, and a plurality of pistons that are slidably inserted into the cylinders of the cylinder block;
A piston rod portion of these pistons and a cylinder inner surface contact portion that is located on the inner side of the cylinder block and is in contact with the inner surface of the cylinder from the piston rod portion are integrally formed, and the cylinder inner surface contact portion In a hydraulic rotating machine equipped with a piston ring in the vicinity of
Either one of the inlet part of the cylinder in which the piston rod part of the piston is in sliding contact and the piston rod part in sliding contact with the inlet part is provided with a copper alloy material part, and the other is formed of an iron-based material. Features a hydraulic rotating machine. In the invention of claim 1,
The copper alloy material portion is provided in the inlet portion of the cylinder, and the copper alloy material portion is cast with a copper alloy material mainly containing Cu-Sn or a copper alloy material mainly containing Cu-Zn. A hydraulic rotating machine characterized by comprising: In the invention of claim 2,
The hydraulic rotary machine according to claim 1, wherein the cylinder block is made of an iron-based material, and the cylinder block is subjected to nitriding after casting of the copper alloy material forming the copper alloy material portion. In the invention of claim 1,
The copper alloy material portion is provided in the inlet portion of the cylinder, and the copper alloy material portion is made of a copper alloy material bushing mainly composed of Cu-Sn or a copper alloy material mainly composed of Cu-Zn. A hydraulic rotating machine comprising a bush. In the invention of claim 4,
A hydraulic rotating machine, wherein the cylinder block is made of an iron-based material to be nitrided. In the invention of claim 1,
The copper alloy material portion is provided in the piston rod portion of the piston, and the copper alloy material portion is cast from a copper alloy material mainly composed of Cu-Sn or a copper alloy material mainly composed of Cu-Zn. A hydraulic rotating machine characterized by comprising. In the invention of claim 6,
The hydraulic rotary machine according to claim 1, wherein the piston is made of an iron-based material, and the piston is subjected to nitriding after casting of the copper alloy material forming the copper alloy material portion. In the invention of claim 6 or 7,
A hydraulic rotating machine, wherein the cylinder inner surface contact portion is provided with another copper alloy material portion. In the invention of claim 8,
The hydraulic rotating machine according to claim 1, wherein the piston is subjected to nitriding after casting of a copper alloy material forming the another copper alloy material portion.

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