JP3786085B2 - Sliding mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sliding mechanism, and more particularly to a sliding mechanism that includes a shoe and a washer that are in sliding contact with each other and is suitable for use in, for example, a hydraulic transmission.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a sliding mechanism for a hydraulic transmission, a first washer that has one end surface as a sliding contact surface and the other end surface supported by a support member, and a sliding contact surface of the washer at one end in an axial direction. A thing provided with the shoe which formed the sliding contact surface is known (for example, patent documents 1).
[Patent Document 1]
Japanese Patent Laid-Open No. 9-14125.
[0003]
[Problems to be solved by the invention]
By the way, in the conventional sliding mechanism described above, the outer peripheral edge of the first sliding contact surface of the shoe is chamfered. With such a configuration, the first sliding contact surface of the shoe is intended to smoothly contact the sliding contact surface of the washer.
However, the conventional shoe is manufactured by using high-strength brass as a material and cutting the material. For this reason, the conventional shoe has a drawback of high manufacturing cost.
In addition, as described above, since the first sliding contact surface of the conventional shoe is a flat surface, it is difficult for the lubricating oil to be drawn between the first sliding contact surface of the shoe and the sliding contact surface of the washer. There were drawbacks. As described above, when the pulling property of the lubricating oil is poor, the wear of the shoe and the washer progresses quickly, and thus the conventional sliding mechanism has a drawback that the life is short.
[0004]
[Means for Solving the Problems]
In view of the circumstances described above, the present invention provides a washer in which one end surface is a sliding contact surface and the other end surface is supported by a support member, and a first slide that is in sliding contact with the sliding contact surface of the washer at one end in the axial direction. In a sliding mechanism comprising a shoe with a contact surface,
The shoe is manufactured by forging using an iron-based material, a circular recess is formed in the center of the first sliding contact surface of the shoe, and a central region of the first sliding contact surface is formed on the outer side. It bulges in the axial direction from the region, the bulge amount is set to 0.5 μm or more and 30 μm or less, and a chamfered portion is formed at an outer position adjacent to the outer peripheral edge of the first sliding contact surface. The chamfered portion is formed so as to form an angle of 10 degrees to 15 degrees with respect to a virtual plane orthogonal to the axial center of the shoe, and the radial dimension of the chamfered portion is 0.4 to 0.7 mm. And the axial dimension of the chamfered portion is set to 50 μm, the first sliding contact surface and the outer peripheral surface of the shoe are connected via the chamfered portion, and the first sliding contact is set. The boundary between the outer peripheral edge of the surface and the chamfered portion is formed in a circular arc cross section, and the circular shape The corner part which becomes the boundary between the outer peripheral edge of the part and the end part on the center side of the first sliding contact surface is chamfered in a cross-sectional arc shape, and further, the washer is manufactured using a copper-based material, When the slidable contact surface of the washer and the first slidable contact surface of the shoe are in slidable contact, a cross section is formed by both the slidable contact surfaces inside and outside the bulged central region of the first slidable contact surface. A minute annular space portion having a wedge shape is formed.
According to such a configuration, the lubricating oil is easily drawn into the sliding contact portion between the first sliding contact surface and the sliding contact surface of the washer through the minute annular space . That is, the pulling property of the lubricating oil between the first slidable contact surface of the shoe and the slidable contact surface of the washer is improved as compared with the conventional case. Therefore, it is possible to provide a sliding mechanism having a longer life compared to the conventional one.
In addition, since an iron-based material having a low unit price is used as the shoe material, a shoe with a low manufacturing cost can be provided. In addition, since the shoe is manufactured by forging, the material yield is good, and the processing time of the shoe can be shortened as compared with the conventional cutting.
Furthermore, since the washer is made of a copper-based material, it is difficult for seizure to occur when the first sliding contact surface of the shoe and the sliding contact surface of the washer slide. Therefore, a sliding mechanism with good seizure resistance and a long life can be provided.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the illustrated embodiment. FIG. 1 shows a main part of a hydraulic mission using the sliding mechanism 1 of the present embodiment.
This hydraulic transmission is integrated with a rotating shaft 6 that is rotatably supported by a bearing (not shown), an annular swash plate 5 that passes through the rotating shaft 6, and a tip (left end portion) of the rotating shaft 6. And a cylindrical cylinder block 7 connected to each other. The cylinder block 7 is formed with a plurality of cylinders 7A each having a bottomed hole at equally spaced positions in the circumferential direction, and a round bar-like piston 4 is slidably fitted to each cylinder 7A.
The sliding mechanism 1 is interposed between the spherical portion 4 </ b> A of each piston 4 and the swash plate 5, and this sliding mechanism 1 has an annular shape slidably superposed on the surface of the swash plate 5. The washer 3 is composed of a plurality of shoes 2 that engage with the spherical portion 4A of each piston 4 and are in sliding contact with the washer 3.
As shown in FIG. 3, the surface of the washer 3 is a sliding contact surface 3 </ b> A that is in sliding contact with the first sliding contact surface 2 </ b> A of the shoe 2, and the back surface 3 </ b> B of the washer 3 is polymerized on the surface of the swash plate 5. ing. As described above, since the back surface of the washer 3 is merely superposed on the end surface of the swash plate 5, the washer 3 and the swash plate 5 can slide in the circumferential direction or the radial direction.
The swash plate 5 and the washer 3 supported by the swash plate 5 are held in a state of surrounding the rotating shaft 6 and inclined by a predetermined angle with respect to the axis of the rotating shaft 6. When necessary, the swash plate 5 and the washer 3 supported by the swash plate 5 have a holding position at a position perpendicular to the rotation shaft 6 from the inclined position shown in FIG. Can be switched.
[0006]
The shoe 2 is formed in a substantially columnar shape, and the outer peripheral portion on the washer 3 side is a large diameter portion 2C. The end surface of the large diameter portion 2C facing the washer 3 is the first sliding contact surface 2A. In addition, a circular concave portion 2D having a shallow bottom is formed on the center side of the end surface facing the washer 3. The central portion of the recess 2D and the central portion of the second sliding contact surface 2B are communicated by a stepped through hole 2E. With such a configuration, the first sliding contact surface 2A having an annular shape is formed on the outer side of the recess 2D, and the first sliding contact surface 2A is brought into contact with the sliding contact surface 3A (front surface) of the washer 3. I am letting.
Further, a hemispherical recess is formed on the end surface opposite to the first sliding contact surface 2A, and this is used as the second sliding contact surface 2B. The spherical portion 4A of the piston 4 is slidably engaged with the second sliding contact surface 2B.
[0007]
Since the hydraulic pressure is acting in each cylinder 7A of the cylinder block 7, each shoe 2 engaged with each piston 4 and its spherical portion 4A is urged toward the washer 3. Accordingly, the first sliding contact surface 2A of each shoe 2 is lightly pressed against the sliding contact surface 3A of the washer 3, and the first sliding contact surface 2A and the sliding contact surface 3A of the washer 3 slide in this state. It has become. The back surface of the washer 3 is also lightly pressed against the surface of the swash plate 5.
When the rotary shaft 6 and the cylinder block 7 are rotated by a driving source (not shown), the pistons 4 and the shoes 2 are rotated about the axis of the rotary shaft 6 as a rotation center. Then, the first sliding contact surface 2A of each shoe 2 comes into sliding contact with the sliding contact surface 3A of the washer 3 held in the inclined state shown in FIG. It has come to be.
The above configuration is not different from the conventionally known sliding mechanism 1 of a hydraulic mission.
[0008]
Thus, in this embodiment, the sliding mechanism 1 is improved as follows, thereby reducing the manufacturing cost of the sliding mechanism 1 and extending its life.
That is, in this embodiment, the shoe 2 is manufactured by forging using an iron-based material (SUJ2) as a material.
Further, as shown in an enlarged cross-sectional view in FIG. 2, the first sliding contact surface 2 </ b> A of the shoe 2 is not a completely flat surface orthogonal to the axis C of the shoe 2, and the center side (axis The region 2a on the center C side) bulges out from the region 2b on the outer side, whereby the cross section of the first sliding contact surface 2A has a smooth arc shape.
In FIG. 2, only the cross section above the axis C of the first sliding contact surface 2A is shown, and the sectional shape of the first sliding contact surface 2A below the axis C is as follows. Since it appears symmetrically with the upper side, the display is omitted in FIG.
In the present embodiment, the outer diameter D of the large-diameter portion 2C in the shoe 2 is 16 mm, and the central region 2a of the first sliding contact surface 2A is the outer peripheral edge 2b ′ of the outer region 2b (that is, the first The bulging amount L that bulges in the axial direction from the outer peripheral edge 2d of the sliding surface 2A is set to 0.5 μm to 30 μm, more preferably 1 μm to 15 μm.
[0009]
Further, a portion on the outer side adjacent to the outer peripheral edge 2d of the first sliding contact surface 2A is a chamfered portion 2e, and the chamfered portion 2e is 15 with respect to a virtual plane orthogonal to the axis C. It is chamfered to make an inclination of less than 1 degree. The boundary between the chamfered portion 2e and the outer peripheral surface of the large-diameter portion 2C is chamfered in a circular arc shape, and the boundary portion between the chamfered portion 2e and the outer peripheral edge 2d of the first sliding contact surface 2A is a cross-section. Are connected by a smooth arc 11. The radial dimension for providing the chamfered portion 2e is 0.4 mm to 0.7 mm, and the axial dimension for providing the chamfered portion 2e is 50 μm. The angle between the chamfered portion 2e and a virtual flat surface orthogonal to the axis C may be 10 degrees to 14 degrees.
Moreover, the corner | angular part 8 used as the boundary of the recessed part 2D provided in the center of 2 A of 1st sliding surfaces and the 1st sliding contact surface 2A is chamfering in cross-sectional arc shape.
In the shoe 2 of this embodiment having such a configuration, after the material is formed by forging, gas soft nitriding treatment is finally applied to the entire area of the first sliding contact surface 2A and the chamfered portion 2e.
[0010]
On the other hand, the washer 3 of this embodiment is manufactured using a copper-based material in connection with manufacturing the shoe 2 using an iron-based material.
That is, the washer 3 of the present embodiment is made of high-strength brass (for example, FABM or FAB manufactured by Mitsui Mining & Smelting Co., Ltd.) and is formed in a ring shape as a whole. Thus, the washer 3 of the present embodiment is made of high-strength brass and is configured to be combined with the shoe 2 made of the iron-based material. Therefore, when the first slidable contact surface 2A of the shoe 2 made of iron-based material and the slidable contact surface 3A of the washer 3 made of copper-based material are in slidable contact, seizure hardly occurs in these slidable contact portions. Yes.
[0011]
As described above, in the sliding mechanism 1 of the present embodiment, the shoe 2 is manufactured by forging using an iron-based material. Therefore, the processing time when manufacturing the shoe 2 can be significantly shortened compared with the case of the conventional cutting process. Further, since the shoe 2 is manufactured by forging as compared with the cutting process, the yield of the material is extremely good. Furthermore, since the shoe 2 of the present embodiment uses an iron-based material (SUJ2), the manufacturing cost can be reduced as compared with the conventional case in which high-strength brass is used.
Moreover, the shoe 2 of the present embodiment bulges the central region 2a of the first sliding contact surface 2A by 0.5 μm or more and 30 μm or less, more preferably 1 μm or more and 15 μm or less than the outer peripheral edge 2d.
Therefore, when the first slidable contact surface 2A of the shoe 2 is slidably contacted with the slidable contact surface 3A of the washer 3, the cross-section is made wedge-shaped by the two members at the radially inner and outer positions of the central region 2a. An annular space is formed. Thereby, the lubricating oil is easily drawn into the sliding contact portions (the first sliding contact surface 2A and the sliding contact surface 3A) of both members through the space portion.
Further, the shoe 2 has a central region 2a that bulges more than the outer region 2b. Therefore, even if the shoe 2 is inclined when it is in sliding contact with the washer 3, the shoe 2 comes into contact with the sliding contact portion of both members. The shoe 2 can slide smoothly with the washer 3.
That is, the sliding mechanism 1 of the present embodiment has a good pulling property of the lubricating oil, and therefore can provide the sliding mechanism 1 having a longer life than the conventional one.
[0012]
In addition, since the washer 3 of this embodiment is made of high-strength brass, the washer 3 is combined with the shoe 2 made of an iron-based material, thereby improving seizure resistance.
Further, since the washer 3 is made of high-strength brass with high strength, the washer 3 can ensure fatigue resistance even under high pressure (maximum 320 kg / cm ² ), and deformation of the sliding contact surface 3A is also possible. Can be prevented.
In the above-described embodiment, the case where the washer 3 and the swash plate 5 are held at predetermined positions and the rotating shaft 6 and the cylinder block 7 are rotated has been described. The present invention can also be applied to a configuration in which the washer 3 is polymerized on the support surface and the shoe 2 is slid on the washer 3 in that state.
In the above embodiment, high-strength brass is used as the material of the washer 3, but aluminum bronze, spring phosphor bronze, or copper sintered bimetal may be used instead.
[0013]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a sliding mechanism that has a longer life than the conventional one.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is an enlarged view exaggerating the main part of FIG.
3 is a front view of the washer 3 shown in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Sliding mechanism 2 ... Shoe 2A ... 1st sliding contact surface 2a ... Center side area | region 2b ... Outer side area | region 3 ... Washer 3A ... Sliding contact surface 5 ... Swash plate (support member)

Claims (3)

A slide provided with a washer having one end surface as a sliding contact surface and the other end surface supported by a support member, and a shoe having a first sliding contact surface in sliding contact with the sliding contact surface of the washer at one end in the axial direction. Dynamic mechanism,
The shoe is manufactured by forging using an iron-based material, a circular recess is formed in the center of the first sliding contact surface of the shoe, and a central region of the first sliding contact surface is formed on the outer side. Bulge in the axial direction from the region, the amount of bulge is set to 0.5 μm or more and 30 μm or less,
A chamfered portion is formed at an outer position adjacent to the outer peripheral edge of the first sliding contact surface, and the chamfered portion forms an angle of 10 degrees to 15 degrees with respect to a virtual plane orthogonal to the shoe axis. The radial dimension of the chamfered portion is set to 0.4 to 0.7 mm, and the axial dimension of the chamfered portion is set to 50 μm. The first slidable contact surface and the outer peripheral surface of the shoe are connected, and the boundary between the outer peripheral edge of the first slidable contact surface and the chamfered portion is formed in a circular arc shape in cross section,
Moreover, the corner | angular part used as the boundary of the outer periphery of the said circular recessed part and the edge part of the center side in the said 1st sliding contact surface is chamfered in cross-sectional arc shape,
Furthermore, the washer is manufactured using a copper-based material,
When the slidable contact surface of the washer and the first slidable contact surface of the shoe are in slidable contact, the two slidable contact surfaces are cross-sectioned inside and outside in the radial direction of the bulged central region of the first slidable contact surface. A sliding mechanism characterized in that a minute annular space having a wedge shape is formed. The sliding mechanism according to claim 1, wherein nitriding treatment is applied to the entire area of the first sliding contact surface. The sliding mechanism according to claim 1 or 2, wherein the washer is made of any one of aluminum bronze, high-strength brass, phosphor bronze for springs, and a copper alloy bimetal material.

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