JP3315664B2 - Swash plate pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a swash plate type pump. More specifically, by providing a plurality of pistons parallel to the drive shaft around the drive shaft and supporting the piston by a swash plate surface inclined with respect to a surface perpendicular to the drive shaft, the rotation of the drive shaft is reduced. In addition, the present invention relates to a swash plate pump in which each piston reciprocates to repeat suction and discharge at a predetermined angular position.

[0002]

2. Description of the Related Art A conventional swash plate type axial piston pump (hereinafter simply referred to as a swash plate pump) has a drive shaft (rotation) as disclosed in Japanese Patent Application Laid-Open No. Hei 5-340346. Rolling bearings such as roller bearings and needle bearings are often used as bearings for rotatably supporting a shaft. However, a rolling bearing is also used because it is generally more expensive than a sliding bearing, and vibration and noise are large (see JP-A-2-161176 and JP-A-9-209918). However, since the sliding bearing has a large contact area with the drive shaft, it is necessary to constantly supply lubricating oil, and there is also a concern that frictional resistance increases due to oil film destruction.

[0003] Such a problem can be solved by reducing the contact pressure between the inner peripheral surface of the bearing and the outer peripheral surface of the drive shaft. On the other hand, in the swash plate pump, the piston receives a reaction force from the swash plate with the rotation of the drive shaft, and this reaction force is applied to the central portion of the drive shaft. Due to such properties,
As the load applied to the bearing increases, the supported portion of the drive shaft slightly tilts, which causes the contact pressure between the bearing and the drive shaft to locally increase.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and reduces the contact pressure between the bearing and the drive shaft. Even when the supported portion of the drive shaft is inclined, the contact pressure is locally reduced. It is an object of the present invention to provide a swash plate type pump capable of preventing an increase.

[0005]

SUMMARY OF THE INVENTION A swash plate pump according to the present invention comprises a housing, a drive shaft rotatably supported on the housing via a sliding bearing, a rotary shaft that rotates with the drive shaft, and rotates around the drive shaft. A plurality of pistons disposed, and a piston fixed to the drive shaft and supporting the pistons
And a swash plate having a down support surface, the inner peripheral surface of the sliding bearing, intersection angle formed drive shaft and the said piston support surface is first filler opening which opens on a side is obtuse is formed A second oil supply port is formed on the inner peripheral surface of the slide bearing, and the first oil supply port is configured to be supplied with oil at a pressure higher than the pressure around the slide bearing. A communicating lubricating oil passage is formed through the slide bearing, and the drive shaft comes into contact with the side surface of the slide bearing to drive.
A locking part is provided to support the axial force of the shaft on the side of the sliding bearing
Radially on the surface of the locking portion on the slide bearing side.
The formed oil groove is formed .

With this configuration, the pressure of the high-pressure oil is applied to the supported portion of the drive shaft in the bearing in a direction opposite to the direction in which the reaction force is applied. Therefore, the contact pressure between the supported portion of the drive shaft and the bearing can be reduced. In addition, this high-pressure oil also exerts a lubricating function. Further, the lubricating oil inside the pump housing can be suitably used for lubricating the bearing. Furthermore, lubricating oil is applied to the bearing by the oil groove.
It can be circulated efficiently, and the locking part and the bearing
During the lubrication.

The first oil supply port is communicated with the discharge portion of the swash plate type pump so that the oil discharged by the swash plate pump is supplied to the first oil supply port, thereby providing a special oil supply means. The high pressure oil can be supplied to the bearing without using the mechanism in the pump .

[0008]

[0009]

[0010]

[0011]

Another swash plate type pump according to the present invention is provided with a housing, a drive shaft rotatably supported on the housing via a slide bearing, and disposed around the drive shaft so as to rotate with the drive shaft. A plurality of pistons, and a swash plate having a piston support surface inclined with respect to the drive shaft and supporting the piston are provided, and a through-hole for driving shaft insertion is formed in the housing, and the through-hole is formed in the through-hole. A flexible support cylinder is closely fitted, the slide bearing is fitted inside the support cylinder, and the portion of the through hole closer to the inside of the housing is enlarged so that a gap is formed between the support cylinder and the outer peripheral surface of the support cylinder. In addition, the outer peripheral surface of the sliding bearing near the outside of the housing is reduced in diameter so that a gap is formed between the outer peripheral surface and the inner peripheral surface of the support cylinder.

Therefore, even if the supported portion of the drive shaft is inclined, the slide bearing is bent by bending the support cylinder in accordance with the inclination of the drive shaft, so that a local contact force is generated between the bearing and the drive shaft. Is prevented.

The above-described through hole of the housing may be a hole directly penetrating the housing wall or an inner diameter side of the bush after a bush or the like is interposed in this hole.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a swash plate type pump according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of a swash plate type pump according to the present invention.

The swash plate type pump 1 is a hydraulic pump,
A swash plate 3 is fixed in a housing 2, and a drive shaft 4 is provided so as to penetrate the housing 2 and the swash plate 3. The swash plate 3 is inclined from a plane orthogonal to the drive shaft 4. The intersection angle between the swash plate 3 and the drive shaft 4 is maximum below the figure. A cylinder block 5 is mounted around the drive shaft 4, and a plurality of cylinders 6 are formed on the cylinder block 5 on a circumference surrounding the drive shaft in parallel with the drive shaft. A piston 7 of the same length penetrates each cylinder 6. A thrust plate 8 is attached to the swash plate 3, and a piston shoe 10 accommodating the spherical top 9 of each piston 7 is in sliding contact with the thrust plate 8 by being held by a shoe retainer 10a. Reference numeral 11 denotes a discharge chamber (hereinafter, also referred to as a discharge unit) of the swash plate pump. Reference numeral 12 denotes a swash plate support for supporting the swash plate 3 by the spherical seat 12a, and reference numeral 13 denotes an angle adjusting mechanism for adjusting the inclination angle of the swash plate 3.

When the drive shaft 4 is rotationally driven, the cylinder block 5 also rotates integrally, and all the pistons 7 rotate integrally while being held by the piston shoe 10 and the shoe retainer 10a. Since the top portion 9 of the piston 7 is in sliding contact with the thrust plate 8 of the inclined swash plate 3 via the shoe retainer 10a, the piston 7 reciprocates in the cylinder 6 with rotation. That is, when the drive shaft 4 rotates counterclockwise as viewed from the right to the left in FIG. 1, when the piston 7 passes through the front side of the drawing, the piston 7 moves in a direction to come out of the cylinder 6, so that a suction process is performed. When passing through the side, it moves in the direction in which it is inserted into the cylinder 6, so that a discharge step is performed. A suction chamber (not shown) is formed on the front side of the drawing, and a discharge chamber (discharge unit) is formed on the other side.
11 are formed.

A drive shaft 4 is provided at each end of the housing 2.
Are rotatably supported. Both 14 and 15 are plain bearings, and the housing 2
Of the drive shaft. Lubricating oil is injected into the inside of the swash plate type pump 1 to lubricate each part in a wet state.

The left end side of the drive shaft 4 in the figure is connected to a drive unit (not shown) such as a motor. A lubricating oil passage 17 and a high-pressure oil passage 18 are bored in the bearing 14 on the driving side (left side in the figure). The lubricating oil passage 17 penetrates vertically and horizontally through the bearing 14 so that the lubricating oil in the housing 2 reaches the sliding contact surface between the bearing 14 and the drive shaft 4, and a second oil supply port opened on the inner peripheral surface of the bearing 14. It communicates with the lubricating oil opening 17a.

The high-pressure oil passage 18 is formed on the inner peripheral surface of the bearing 14 at a lower portion in the drawing (in the direction of 6 o'clock in the clock, the direction in which the crossing angle between the swash plate 3 and the drive shaft 4 is maximized). As shown in FIG. 2 and FIG. 3, the high pressure oil opening 18a serving as the first oil supply port communicates with the discharge portion 11 of the pump 1. Therefore, the high-pressure oil from the discharge unit 11 is jetted into the bearing 14 so as to push the drive shaft 4 upward through the high-pressure oil passage 18. On the other hand, in a swash plate pump, the piston receives a reaction force from the swash plate with the rotation of the drive shaft. The drive shaft receives the component of the downward component of the reaction force applied to the central portion, and the bearing supports the lower component. However, since the high-pressure oil that pushes the drive shaft 4 upward shares the support of the lower component of the bearing 14, damage to the bearing is prevented. This is because the high-pressure oil is supplied at a much higher pressure than the lubricating oil in the housing circulating through the lubricating oil passage 17. Of course, this high-pressure oil also contributes to lubrication of the bearing 14.

The high-pressure oil passage 18 is open at only one position in the 6 o'clock direction on the inner peripheral surface of the bearing 14, but is not limited thereto. It may be opened at a location. In short, it may be formed at any position where an upward force by the high-pressure oil is applied to the drive shaft 4.

The high pressure oil passage 18 may use an existing oil passage. For example, as shown in FIG. 2, in the case where a high-pressure lubricating oil passage 18b for supplying high-pressure lubricating oil is formed near the contact portion between the swash plate 3 and the swash plate support 12 from the discharge portion of the pump. The high-pressure oil passage 18 may be formed so as to branch off from the high-pressure lubricating oil passage 18b. FIG.
2A is a partial sectional view taken along the line II-II in FIG. 2B, and FIG. 2B is a diagram schematically showing the high-pressure oil passage 18 and the high-pressure lubricating oil passage 18b.

The above-described lubricating oil passage 17 and high-pressure oil passage 1
8 may be applied to the right bearing 15 in FIG.

As shown in FIG. 1, a ring-shaped locking plate 19 for supporting the axial force of the drive shaft 4 on the bearing 14 is provided at each position on both sides of the drive shaft 4 with the left bearing 14 interposed therebetween. Have been. As shown in FIG. 3, a plurality of oil grooves 20 are formed radially on the surface of the locking plate 19 on the bearing 14 side. As the drive shaft 4 rotates, the lubricating oil escapes to the outside of the bearing 14 through the oil groove 20 due to the centrifugal force, so that the lubricating oil is efficiently circulated. Further, the sliding surface between the locking plate 19 and the bearing 14 can be efficiently lubricated by the lubricating oil passing through the oil groove 20. FIG.
FIG. 3B is an enlarged view of a portion, and FIG.
It is II sectional drawing.

As described above, since the intermediate portion of the drive shaft of the swash plate pump receives a reaction force from the swash plate as it rotates, the drive shaft 4 of FIG. 1 rotates with the intermediate portion slightly bent downward. I do. Therefore, the bearing portion of the drive shaft 4 is slightly inclined downward into the housing. However, it is not inclined when the operation is stopped, and the degree of inclination is extremely small during low rotation. As described above, the degree of inclination changes.

FIGS. 4 to 8 show sliding bearings capable of coping with the change in the inclination of the drive shaft 4.

The bearing 21 shown in FIG. 4 is made of a flexible tubular member, and rotatably supports the drive shaft 4 on the inner diameter side. The bearing 21 is fitted into a through hole 22 for inserting a drive shaft, which penetrates the wall of the housing 2 of the pump. The through-hole 22 has a small-diameter portion 22a from the middle portion where the bearing 21 close to the housing is tightly fitted, and a large-diameter portion 22b near the housing inside B where a gap is formed between the bearing 21 and the outer peripheral surface. It is composed of Therefore, even if the bearing portion (supported portion) of the drive shaft 4 is inclined downward toward the inside of the housing, the portion of the bearing 21 closer to the inside of the housing bends into the large-diameter portion 22b of the through hole 22 and the bearing 21 and the drive A local force is prevented from being applied to the shaft 4. Since the inclination direction of the drive shaft 4 is known, an oblong hole having a long axis in the vertical direction may be formed instead of the large-diameter portion 22b. However, the large-diameter portion 22b which is almost a perfect circle
Forming the drive shaft 4 as in the case of an oblong hole.
It is not necessary to rotate the bearing 21 in the direction in which it is inclined to perform alignment. That is, it is not necessary to adjust the rotation of the bearing in accordance with the direction of inclination of the swash plate 3. In other words, it can be said that the bearing structure is adapted to cope with the precession of the bearing portion of the drive shaft 4. With such a structure, processing becomes easy.

In the present embodiment, the small diameter portion 22a and the large diameter portion 22b of the through hole 22 are separated by a step. However, the through hole 22 may be tapered so that the inside diameter increases gradually from the small diameter portion 22a toward the inside of the housing. .

Although the bearing 21 has flexibility, specifically, a rolled steel material for general structure (for example, JISG)
Commercially available plain bearings having a hardness and strength of about 3101 (SS) also exhibit the required flexibility.

The bearing 23 shown in FIG. 5 rotatably supports the drive shaft 4 on the inner diameter side, and the outer peripheral surface is tightly fitted into the through hole 24 of the housing 2. The inner peripheral surface of the bearing 23 is tapered such that the inner diameter increases gradually from the vicinity of the middle in the axial direction toward the inside B of the housing. Therefore, even if the bearing portion (supported portion) of the drive shaft 4 is inclined downward toward the inside of the housing, it is possible to prevent a local force from being applied to the bearing 23 and the drive shaft 4. Of course, the drive shaft 4 is
However, the bearing 23 can cope with any inclination in any relative direction. Further, in FIG. 5, only the portion from the vicinity of the middle in the axial direction to the inside of the housing is formed in a tapered shape in which the inner diameter increases, but the portion from the outside to the inside of the housing, that is, from the left end of the bearing 23 in the drawing. The whole may be tapered toward the right end.

The bearing 25 shown in FIG. 6 rotatably supports the drive shaft 4 on the inner diameter side, and the outer peripheral side is accommodated in the accommodating portion 26 formed on the housing 2 side with some play. FIG. 6A is a front sectional view of the bearing 25, and FIG. 6B is a sectional view taken along line VI-VI of FIG. 6A. A partially spherical recess 27a is formed at a position corresponding to 6 o'clock on the outer peripheral side of the bearing 25, and a spherical support portion 27 which is received by the recess 27a and supports the bearing 25 is formed on the inner surface of the housing portion 26. Is formed. This spherical support 2
7 may be a ball member separate from the housing portion. In the illustrated reference example, the concave portion 27b for accommodating the spherical support portion 27 is also formed on the accommodating portion 26 side, but it is not particularly necessary to form the concave portion 27b. With such a configuration, the bearing 25 can swing in any direction with the spherical support 27 as a fulcrum within the range restricted by the housing 26. Therefore, since the bearing 25 can adapt to the inclination of the drive shaft 4, the bearing 25 and the drive shaft 4
Is prevented from being subjected to local forces.

The bearing 28 shown in FIG. 7 also rotatably supports the drive shaft 4 on its inner diameter side and is attached to the housing 2 so as to be able to swing. That is, the outer peripheral side is accommodated in the accommodating portion 29 formed on the housing side with some play. FIG. 7A is a front sectional view of the bearing 28, and FIG. 7B is a VII-VI of FIG. 7A.
It is an I line sectional view. A groove 30a is formed at a position corresponding to 6 o'clock on the outer peripheral side of the bearing 28 in a tangential direction of the outer periphery, that is, in a direction perpendicular to the drive shaft 4. On the other hand, the inner surface of the housing 29 is
A rod-shaped support portion 31 for supporting the support member 8 is formed. A groove 30 for accommodating the rod-shaped support portion 31 is provided in the accommodation portion 29.
b is formed. This rod-shaped support part 31 may be a rod member separate from the accommodation part. With this configuration, the bearing 28 can swing in the direction of the drive shaft 4 with the rod-shaped support portion as a fulcrum within the range restricted by the housing portion 29. Therefore, the bearing 28 can adapt to the inclination of the drive shaft 4, so that a local force is prevented from being applied to the bearing 28 and the drive shaft 4.

The bearing 32 shown in FIG. 8 also rotatably supports the drive shaft 4 on the inner diameter side. On the other hand, a flexible cylindrical support member (support cylinder) 34 is fitted in the through hole 33 of the housing 2. The through-hole 33 is provided between the intermediate portion and the support cylinder 3 which is a portion closer to the housing exterior.
4 includes a small-diameter portion 33a in which the cylinder 4 closely fits, and a large-diameter portion 33b which is a portion closer to the inside of the housing where a gap is formed between the outer peripheral surface of the support cylinder 34. Further, the outer peripheral surface of the bearing 32 has a large-diameter portion 35 b closer to the outside of the housing, which is closely fitted to the inner diameter side of the support cylinder 34, and a portion closer to the inside of the housing where a gap is formed between the inner peripheral surface of the support cylinder 34. A small diameter portion 35a is formed.

Therefore, even if the supported portion of the drive shaft 4 is inclined downward toward the inside of the housing, the large-diameter portion 35b on the outer peripheral surface of the bearing 32 pushes the portion of the support cylinder 34 closer to the inside of the housing, thereby increasing the size of the through hole 33. Since the bearing 32 and the drive shaft 4 are bent in the radial portion 33b, a local force is prevented from being applied.

The step 33c between the small-diameter portion 33a and the large-diameter portion 33b in the through hole 33 and the step 35c between the small-diameter portion 35a and the large-diameter portion 35b on the outer peripheral surface of the bearing 32 correspond to the drive shaft shaft. It is not necessary to coincide with the direction, and if it is a little dimension, it may be changed.

The support cylinder 34 has flexibility, and specifically, is a rolled steel material for general structure (for example, JI
A material having hardness and strength on the order of (SS) of SG3101 also exhibits necessary flexibility.

FIG. 9 shows a conventional shaft bearing 36 having a constant inner diameter and a drive shaft 37 having a supported portion tapered. The tapered portion is slightly longer than the width of the bearing 36. With this configuration, the tapered outer surface of the drive shaft 37 follows the inner surface of the bearing 36 even when the supported portion of the drive shaft 4 is inclined downward into the housing.
Is prevented from being subjected to local forces.

The through hole 22 shown in FIG. 4 and the bearing 23 shown in FIG.
In the case where the supported portion of the drive shaft 37 in FIG. 9 is tapered, the shape of the tapered surface in the axial section need not be particularly linear. For example, the shape may be a slightly convex arc.

[0040]

According to the present invention, the contact pressure between the bearing and the drive shaft can be reduced, and the contact pressure can be prevented from being locally increased even when the supported portion of the drive shaft is inclined.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a swash plate type pump according to the present invention.

FIG. 2A is a partial sectional view taken along the line II-II of FIG. 2B, and FIG. 2B is a diagram schematically showing a high-pressure oil passage and a high-pressure lubrication oil passage.

FIG. 3A is an enlarged view of a portion A in FIG. 1, and FIG.
FIG. 3B is a sectional view taken along line III-III of FIG.

FIG. 4 is a sectional view showing a bearing in a reference example of the swash plate pump.

FIG. 5 is a sectional view showing a bearing in another reference example of the swash plate pump.

6 (a) is a front sectional view showing a bearing in still another reference example of the swash plate type pump, and FIG. 6 (b) is a sectional view taken along the line VI-VI of FIG. 6 (a).

7 (a) is a front sectional view showing a bearing in still another reference example of the swash plate pump, and FIG. 7 (b) is a sectional view taken along line VII-VII of FIG. 7 (a).

FIG. 8 is a sectional view showing a bearing in still another embodiment of the swash plate pump of the present invention.

FIG. 9 is a sectional view showing a main part of a drive shaft in still another reference example of the swash plate type pump of the present invention.

Continuing from the front page (72) Inventor Hidekazu Kobayashi 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Akashi Plant (72) Inventor Susumu Hasegawa 234, Matsumoto, Hazeya-cho, Nishi-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Inside the Nishi-Kobe Plant (72) Inventor Yasuo Omi 234, Matsumoto, Hazeya-cho, Nishi-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. (56) References JP-A-8-254185 (JP, A) JP-A-10-122229 (JP, A) JP-A-61-28769 (JP, A) JP-A-5-52180 ( JP, A) JP-A-9-217675 (JP, A) JP-A-3-253775 (JP, A) JP-A-60-46803 (JP, A) JP-A-10-238486 (JP, A) Hei 4-76974 (JP, U) Japanese Utility Model Showa 60-164682 (JP, U) Special Table Hei 4-503236 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 1/00-19/24 F04B 23/00-23/04 F04B 53/00-53/22

Claims (3)

(57) [Claims] 1. A housing, a drive shaft rotatably supported by a slide bearing on the housing, a plurality of pistons rotating with the drive shaft and disposed around the drive shaft, and a drive shaft. And a swash plate having a piston support surface that supports the piston and that is inclined with respect to a side of the inner peripheral surface of the slide bearing, where a crossing angle between the drive shaft and the piston support surface is an obtuse angle. A first refueling port is formed in the sliding bearing, and a second refueling port is formed on the inner peripheral surface of the slide bearing. The first refueling port is configured to be supplied with a pressure higher than a pressure around the sliding bearing. A lubricating oil passage communicating between the second oil supply port and the inside of the housing is formed through the sliding bearing, and abuts the drive shaft on a side surface of the sliding bearing to apply an axial force of the driving shaft to the sliding bearing. There is a locking part to be supported on the side In which, on the sliding bearing side surface of the engaging portion, the swash plate type pump comprising an oil groove formed in the radial direction is formed. 2. The swash plate type pump according to claim 1, wherein the first oil supply port communicates with a discharge portion of the swash plate type pump, and oil discharged by the swash plate pump is supplied to the first oil supply port. Swash plate pump . 3. A housing, a drive shaft rotatably supported on the housing via a slide bearing, a plurality of pistons rotating with the drive shaft and disposed around the drive shaft, and a drive shaft. And a swash plate that supports the piston by a surface that has a piston support surface that supports the piston and that is inclined with respect to the housing. A through-hole for driving shaft insertion is formed in the housing. A flexible support cylinder is tightly fitted in the hole, the slide bearing is fitted in the support cylinder, and a portion of the through-hole closer to the inside of the housing has a gap between the support cylinder and the outer peripheral surface of the support cylinder. A swash plate pump in which the outer peripheral surface of a portion of the slide bearing closer to the outside of the housing is reduced in diameter so that a gap is formed between the outer peripheral surface and the inner peripheral surface of the support cylinder.