JPH08151975A - Axial piston pump motor - Google Patents

Abstract

PURPOSE: To prevent generating lateral force in a direction different from a sliding direction between a piston and a cylinder block. CONSTITUTION: A device comprises a plurality of pistons 16 mounted to be received reciprocatably on a concentrical circle of a rotary axis of a cylinder block 14, ring member 19 tilted to a rotary axial center of the cylinder block 14 also come into contact with a point end of the piston 16, rotary shaft member 12 rotated synchronously with the cylinder block 14 and a shoe 23 brought into spherical surface contact with the ring member 19. Further a rotation transmitting mechanism, synchronously rotating a contact surface 16a orthogonal to an axial center provided in a point end of the piston 16, flat surface 23b provided in the shoe 23 brought into surface contact with this contact surface 16a, cylinder block 14 and the ring member 19, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an axial piston pump / motor such as a swash plate type or an oblique axis type, and more specifically, an acting force in a direction different from the reciprocating direction is generated between a cylinder block and a piston. I did not try to do it.

[0002]

2. Description of the Related Art As a conventional swash plate type axial piston pump, which is disclosed in, for example, Japanese Patent Laid-Open No. 6-129344, it is constructed as shown in FIGS.

In FIG. 31, a cylinder block 2 that rotates integrally with a drive shaft 1 is formed with a plurality of cylinders 2a at equal intervals on the same circumference centered on the drive shaft 1. A piston 4 that reciprocates in the direction is accommodated. A piston ball portion 4a is integrally formed at the tip of the piston 4, and the piston ball portion 4a is the shoe 5 of the swash plate 6.
It is rotatably fitted in a spherical hole 5a provided in the. The rear surface of the shoe 5 rotates in the same manner as the cylinder block 2 while slidingly contacting the surface of the swash plate 6 via the pad 5b. The swash plate 6 is fixed to a housing (not shown) in a state of being inclined at a predetermined angle with respect to the drive shaft 1, or in a variable type, the swash plate angle is configured to change via an actuator. The rear surface of the cylinder block 2 is in sliding contact with the valve plate 7 having a pair of ports 7a.

When the cylinder block 2 rotates integrally with the drive shaft 1, each piston 4 contacting the swash plate 6 via the shoe 5 reciprocates in the cylinder 2a with one rotation of the cylinder block 2 as one cycle. . In the stroke in which the piston 4 extends, the fluid is sucked into the cylinder 2a via one port 7a in the valve plate 7, and in the stroke in which it is pushed in, the other port 7 is opened.
The fluid in the cylinder 2a is discharged via a.

In this way, as the axial piston pump, the fluid is sucked and discharged as the cylinder block 2 rotates, and when the high pressure fluid is supplied to the cylinder 2a as the motor in the extension stroke of the piston 4, the fluid is accompanied. As a result, the cylinder block 2 rotates and the drive shaft 1 rotates.

[0006]

By the way, such a swash plate type (or swash shaft type) axial piston pump
In the motor, as shown in FIG. 32, between the piston 4 and the cylinder 2a, as the piston 4 reciprocates,
In addition to the acting force in the reciprocating direction, the acting force in a direction different from this acts.

Now, when the piston 4 begins to move in the compression direction from the most extended state and discharges the fluid, a high fluid pressure is generated in the cylinder 2a according to the load on the discharge passage side. When the force in the axial direction of the piston due to this fluid pressure is F1, the piston 4 is strongly pressed against the swash plate 6 by this F1. Then, the swash plate 6 opposes F1 with a reaction force F2 in the direction perpendicular to the sliding surface. As a result, a force different from the reciprocating (axial) direction is applied to the piston 4, and a force component (lateral force) perpendicular to the sliding surface is applied to both ends of the fitting between the piston 4 and the inner peripheral surface of the cylinder 2a that slides the piston 4. Power) F
3, F4 is generated.

These lateral forces F3 and F4 correspond to F1 acting in the axial direction of the piston 4, the fitting length of the piston 4, the inclination angle of the swash plate 6, and the like. The outer peripheral surface of the piston 4 and the cylinder 2a. Since a large sliding surface pressure is generated between the inner surface of the pump and the pump. Depending on the operating conditions of the motor, it may cause seizure between the piston 4 and the cylinder block 2.

Generally, the scale of the seizure durability of the sliding portion is expressed as the product of the sliding surface pressure and the sliding speed. Therefore, in order to suppress the seizure between the piston 4 and the cylinder block 2, It is necessary to reduce the pump discharge pressure and to suppress the reciprocating speed of the piston 4, that is, the pump discharge amount, which all lead to deterioration in pump performance. Further, the axial length of the piston 4 also requires a certain length of fitting with the cylinder 2a, which hinders size reduction.

Further, as a reaction force of the lateral forces F3 and F4 generated on the side surface of the piston 4, F is applied to the cylinder block 2.
5 and F6 are generated, these F5 and F6 generate a rotation moment M1 in the cylinder block 2, and at the same time, F
F5 and F6 generate frictional forces F7 and F8 with the piston 4. The moment M1 and the frictional forces F7 and F8 press the cylinder block 2 against the valve plate 7 as a force F9 based on the fluid pressure. However, the behavior of the cylinder block 2 becomes complicated, and the cylinder block 2 and the valve plate 7 are complicated. It may worsen the lubrication condition of the sliding surface between and.

The sliding surface pressure between the cylinder block 2 and the valve plate 7 is adjusted by adjusting the sliding area by providing the groove 7b on the valve plate 7.
Produces a hydrostatic bearing-like function to achieve proper surface pressure, but M
1, F7 and F8 make the design shape of the groove 7b extremely complicated, and may cause seizure of the sliding surface or occurrence of excessive leakage, especially when a low-viscosity fluid with low lubricity is used. There is.

By the way, according to German Patent No. 5295589 and German Patent No. 579476, there is an axial piston pump in which the spherical end portion of the piston is not integrally formed but the spherical end portion is divided. Also, a similar structure is described in US Pat.
It is also described in No. 2.

However, in all of these, the piston tip end, which comes into contact with the divided sphere, is constrained to the swash plate so as not to be displaced relative to the rotation direction of the swash plate, and the piston housed in the cylinder block is the same as above. The swash plate is rotatably driven via this. Therefore, even if the spherical portion at the tip of the piston is divided perpendicularly to the piston axis, the torque for driving the swash plate acts as the lateral force of the piston, resulting in a large surface pressure on the sliding surface between the piston and cylinder. This is no different.

The present invention solves such a problem by
Provided is an axial piston pump / motor in which a lateral force different from the sliding direction is not generated between a piston and a cylinder block.

Further, the present invention provides an axial piston pump / motor capable of limiting the force generated in the cylinder block to only the axial component.

[0016]

A first invention is a cylinder block rotatably supported around an axis, and a plurality of pistons reciprocally accommodated on a concentric circle of a rotation axis of the cylinder block. An axial piston pump / motor comprising: a ring member that is inclined relative to a rotation axis of the cylinder block, and a tip end of the piston contacts; and a rotation shaft member that rotates in synchronization with the cylinder block. A shoe that makes spherical contact with the member, a contact surface that is provided at the tip of the piston and that is orthogonal to the axial center, a smooth surface that is provided on the shoe that makes surface contact with the contact surface, the cylinder block, and the ring member. And a rotation transmission mechanism for synchronously rotating.

A second invention is a cylinder block rotatably supported about an axis, and a plurality of pistons reciprocally accommodated on a concentric circle of a rotation axis of the cylinder block,
An axial provided with a ring member that is relatively inclined with respect to the rotation axis of the cylinder block and is in contact with the tip of the piston, and a rotation shaft member that is coaxially connected to the cylinder block and that rotates integrally. In the piston pump / motor, a shoe that makes spherical contact with the ring member, an abutment surface that is provided at the tip of the piston and that is orthogonal to the axial center, and a smooth surface that is provided in the shoe that makes surface contact with the abutment surface. A rotation transmission mechanism that synchronously rotates the cylinder block and the ring member is provided.

A third invention is a cylinder block rotatably supported about an axis, and a plurality of pistons reciprocally accommodated on a concentric circle of a rotation axis of the cylinder block,
A ring member, which is inclined relative to the rotation axis of the cylinder block and is in contact with the tip of the piston, and a rotation shaft member which is coaxially connected to the ring member and rotates in synchronization with the cylinder block. In an axial piston pump / motor, a shoe that makes spherical contact with the ring member, an abutment surface that is provided at the tip of the piston and that is orthogonal to the axial center, and a smooth surface that is in surface contact with the abutment surface and that is provided on the shoe. , A rotation transmission mechanism for synchronously rotating the cylinder block and the ring member.

In a fourth aspect of the invention, in the first to third aspects of the invention, a spring is provided to urge the piston in the extending direction so as to constantly contact the shoe.

In a fifth aspect based on the second aspect, one surface of the ring member is in slidable contact with an inclined surface of a support provided on the housing and is constrained in the radial direction.

In a sixth aspect based on the fifth aspect, the bearing ring mounted on the support is slidably fitted on the outer periphery of the ring member.

In a seventh aspect based on the third aspect, the ring member is in sliding contact with a support portion provided in the housing, and a bearing ring attached to the support portion is slidably fitted on the outer periphery of the ring member. .

In an eighth aspect based on the sixth or seventh aspect, a hydrostatic bearing is formed on the fitting surface between the bearing ring and the ring member.

In a ninth aspect based on the sixth or seventh aspect, a dynamic pressure bearing or a roller bearing is formed on the fitting surface between the bearing ring and the ring member.

In a tenth aspect based on the first to fourth aspects, an outer peripheral surface of the ring member is supported by an inner peripheral surface of a part of the housing, and a static pressure bearing is formed on the supporting surface. The hydraulic oil is introduced into the pressure bearing via a passage formed in the cross section of the housing.

In an eleventh aspect based on the fifth aspect, a part of the ring member is rotatably supported on the inner peripheral surface of the support base via a bearing.

In a twelfth aspect based on the first to fourth aspects, a part of the ring member is rotatably supported by a part of the inner peripheral surface of the housing via a bearing.

A thirteenth aspect of the present invention is the universal joint according to any one of the first to twelfth aspects, wherein the rotation center of the cylinder block and the center of rotation of the ring member are connected by two axes that are orthogonal to each other as the rotation transmission mechanism. Equipped with.

In a fourteenth aspect based on the first through twelfth aspects, the rotation transmission mechanism includes a universal joint that connects the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member with two axes that are orthogonal to each other. .

In a fifteenth aspect based on the first to twelfth aspects, as the rotation transmission mechanism, there are helical teeth meshing with each other at the abutting ends of the rotation center of the cylinder block and the rotation center of the ring member. Form.

In a sixteenth aspect based on the first through twelfth aspects, as the rotation transmission mechanism, spiral teeth that mesh with each other are formed at the abutting ends of the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member.

In a seventeenth aspect based on the first to twelfth aspects, the rotation transmission mechanism includes a spline hole formed in a rotation center portion of a cylinder block and a spline hole formed in a rotation center portion of a ring member. And a toothed shaft that meshes with each other.

In an eighteenth aspect based on the fourteenth or sixteenth aspect, the rotary shaft member penetrates the central portion of the ring member in a non-interfering state, and both ends of the rotary shaft member are rotatably supported by the housing. There is.

In a nineteenth aspect based on the first through twelfth aspects, the rotation transmission mechanism includes a high-rigidity spring connecting the rotation center of the cylinder block and the rotation center of the ring member.

In a twentieth aspect based on the first to twelfth aspects, the rotation transmission mechanism includes a high-rigidity bellows that connects the rotation center of the cylinder block and the rotation center of the ring member.

In a twenty-first aspect based on the first to twelfth aspects, the rotation transmission mechanism includes a twisted flexible shaft connecting the rotation center of the cylinder block and the rotation center of the ring member.

In a twenty-second aspect of the present invention, in the first to twelfth aspects of the present invention, the rotation transmission mechanism includes a cylindrical flexible shaft connecting the rotation center of the cylinder block and the rotation center of the ring member.

In a twenty-third aspect of the invention, according to the fifth or sixth aspect of the invention, the support base is supported by the housing via a support shaft such that an inclined surface with which the ring member is in sliding contact is tiltable.

In a twenty-fourth aspect according to the fifth or sixth aspect, the back surface of the support table is in contact with the housing as a cylindrical surface or a spherical surface so that the inclined surface of the support table on which the ring member slides can be tilted. .

In a twenty-fifth aspect of the invention, according to the third or seventh aspect, the cylinder block is supported by the housing via a support shaft so as to be tiltable with respect to the ring member.

In a twenty-sixth aspect of the present invention, in the third or the seventh aspect of the invention, the rear surface of the cylinder block support member contacts the housing with a cylindrical surface or a spherical surface so that the cylinder block can be tilted with respect to the ring member.

In a twenty-seventh aspect of the present invention according to any one of the first to twenty-sixth aspects, the shoe is formed into a substantially hemispherical sphere, and its spherical surface is in spherical contact with a hemispherical recess formed in the ring member, and its smooth surface is It is in surface contact with the contact surface of the piston.

The twenty-eighth invention is the twenty-seventh invention, wherein
A lubricating fluid is introduced into the contact surface between the shoe and the piston through a through passage formed in the piston.

A twenty-ninth aspect of the invention is the twenty-eighth aspect of the invention.
The lubricating fluid introduced into the contact surface between the shoe and the piston is introduced into the spherical contact surface between the shoe and the ring member via the through passage formed in the shoe.

The 30th invention is the 29th invention, wherein
The lubricating fluid introduced into the spherical contact surface between the shoe and the ring member is introduced into the sliding contact surface with the bearing ring member through the through passage formed in the ring member.

[0046]

According to the first aspect of the invention, the reaction force in the direction perpendicular to the inclined surface of the ring member is transmitted to the piston through the shoe with respect to the axial pushing force generated as the piston expands and contracts. However, the piston and the shoe are separated on the surface orthogonal to the sliding axis of the piston, and the component force in the direction orthogonal to the piston axis of the reaction force from the ring member is applied to the piston due to the existence of the separation surface. Is hardly transmitted.

On the other hand, the cylinder block accommodating the piston and the ring member with which the piston contacts through the shoe are connected via a rotation transmission mechanism, and the difference in rotational torque between the cylinder block and the ring member is the rotation transmission mechanism. Received by.

As a result, a component force orthogonal to the piston reciprocating direction is not generated between the piston and the cylinder block. Therefore, the sliding surface pressure of the piston is reduced,
It is possible to avoid seizure or shorten the axial direction of the piston. Further, by making the acting force of the cylinder block only the axial component, the surface pressure of the sliding surface between the cylinder block and the valve plate is optimized, and seizure and fluid leakage are prevented.

In the second aspect of the invention, the cylinder block is directly connected to the rotary shaft member, and the ring member is rotated via the rotation transmission mechanism to operate as a swash plate type axial piston pump / motor.

In the third aspect of the invention, the ring member is directly connected to the rotary shaft member, the cylinder block rotates synchronously with the ring member via the rotary shaft mechanism, and operates as a diagonal shaft type axial piston pump / motor. .

According to the fourth aspect of the present invention, the spring for urging the piston in the extending direction allows the piston and the shoe to be kept in contact with each other even when the fluid pressure acting on the piston is small, so that the piston can be reliably operated. .

In the fifth aspect of the invention, the ring member does not move in the radial direction but rotates while slidingly contacting the inclined surface of the support base provided in the housing, and operates with a flow rate characteristic according to the angle of the inclined surface.

In the sixth aspect of the invention, the load in the radial direction applied to the ring member is supported by the bearing ring, and the sliding contact rotation is performed without deviating from the support base.

According to the seventh aspect of the invention, the load in the radial direction applied to the ring member is supported by the bearing ring provided in the supporting portion, and the sliding contact rotation is performed without deviating from the supporting portion.

In the eighth aspect of the invention, the hydrostatic bearing formed on the fitting surface of the bearing ring and the ring member supports the radial load of the ring member and allows the ring member to rotate smoothly.

In the ninth aspect of the invention, the radial load of the ring member is supported by the dynamic pressure bearing or the roller bearing formed on the fitting surface between the bearing ring and the ring member, and the ring member is rotated smoothly.

In the tenth aspect of the invention, the radial load applied to the ring member is supported by the static pressure bearing on the inner peripheral surface of the housing, and the ring member can be smoothly rotated.

In the eleventh aspect of the invention, the radial load of the ring member is supported by the bearing on the inner peripheral surface of the support base, and the ring member can be smoothly rotated. Further, the ring member can be easily attached to the support base.

In the twelfth aspect of the invention, the radial load applied to the ring member is directly supported by the housing via the bearing, so that the ring member can be smoothly rotated.

In the thirteenth invention, as the rotation transmission mechanism,
Since the universal joint that connects the rotation center of the cylinder block and the rotation center of the ring member is provided, it can be compactly stored in a small space.

In the fourteenth invention, as the rotation transmission mechanism,
Since the universal joint that connects the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member is provided, a large torque can be transmitted, and it can be applied to a large capacity.

In the fifteenth invention, as the rotation transmitting mechanism,
Since the spiral teeth that mesh with each other are formed at the rotation center of the cylinder block and the rotation center of the ring member, there is no deviation in the rotation phase between the cylinder block and the ring member due to the rotation angle, and the operating characteristics with less rotation pulsation are obtained.

In the sixteenth invention, as the rotation transmission mechanism,
Since the helical teeth that mesh with each other are formed on the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member, the rotational phase of the cylinder block and the ring member does not deviate due to the rotation angle, and operating characteristics with less rotational pulsation can be achieved. On the other hand, a large torque can be transmitted, and it can be applied to a large capacity.

In the seventeenth invention, as the rotation transmission mechanism,
Since the cylinder block and the spline hole formed in each rotation center of the ring member are connected by both toothed shafts, there is no deviation due to the rotation angle in the rotation phase between the cylinder block and the ring member, and there is little operating pulsation. On the other hand, it can be compactly arranged in a small space.

In the eighteenth aspect of the invention, the rotary shaft member penetrates the center of the ring member and is rotatably supported by the housing at both ends. To be

In the nineteenth aspect of the invention, since the cylinder block and the ring member are connected by the highly rigid spring as the rotation transmitting mechanism, the intersecting shafts are suppressed while suppressing the rotational phase of the cylinder block and the ring member to the minimum. A rotary motion can be transmitted smoothly about the mind.

In the twentieth aspect of the invention, since the cylinder block and the ring member are connected by the bellows of high rigidity as the rotation transmitting mechanism, the intersecting shafts are suppressed while suppressing the rotational phase of the cylinder block and the ring member to the minimum. A rotary motion can be transmitted smoothly about the mind.

In the twenty-first aspect of the invention, since the cylinder block and the ring member are connected by the twisted flexure shaft as the rotation transmission mechanism, the intersecting shafts are suppressed while suppressing the rotational phase of the cylinder block and the ring member to the minimum. A rotary motion can be transmitted smoothly about the mind.

In the twenty-second invention, since the cylinder block and the ring member are connected by the smooth type flexible shaft as the rotation transmission mechanism, the intersecting shafts are suppressed while suppressing the rotational phase of the cylinder block and the ring member to the minimum. A rotary motion can be transmitted smoothly about the mind.

In the twenty-third invention, the support base is tiltable,
By adjusting the effective stroke of the piston abutting on the ring member according to the inclination angle of the support base, it is possible to obtain a variable capacity type characteristic.

In the twenty-fourth aspect of the invention, since the back surface of the supporting base is in contact with the housing in the cylindrical surface or the spherical surface, the reaction force received by the supporting base through the ring member can be supported by the housing, and the durability strength is enhanced.

In the twenty-fifth aspect of the invention, since the cylinder block is tiltably supported, the variable stroke characteristic can be obtained by adjusting the effective stroke of the piston according to the tilt angle of the cylinder block.

In the twenty-sixth aspect of the present invention, the rear surface of the cylinder block support member comes into contact with the housing in the form of a cylindrical surface or a spherical surface, so that the reaction force received by the cylinder block can be supported by the housing, and the durability strength can be enhanced.

In the twenty-seventh aspect of the invention, the shoe interposed between the ring member and the piston has a substantially half-sphere shape, and the structure is simple and the productivity is good.

In the twenty-eighth aspect of the invention, the lubricating fluid is introduced into the contact surface between the shoe and the piston, and a good lubricating function can always be maintained.

In the twenty-ninth aspect of the invention, the lubricating fluid introduced into the contact surface between the shoe and the piston is introduced into the spherical contact surface between the shoe and the ring member, so that good lubricity is obtained even between the shoe and the ring member. Is maintained.

In the thirtieth aspect, the lubricating fluid introduced into the spherical contact surface between the shoe and the ring member is further introduced into the sliding contact surface between the ring member and the bearing ring member, so that there is also a space between them. Good lubricity is maintained.

[0078]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in FIGS. 1 to 3 are embodiments in which the present invention is applied as a swash plate type axial piston pump, in which 11 is a pump housing which penetrates the center of the housing 11. The rotating shaft 12 is rotatably supported by a bearing 13 in a cantilever manner.

The rotary shaft 12 penetrates through the center of the cylinder block 14 and is integrally coupled via the spline portion 18 for the same rotation. The cylinder block 14 is formed with a plurality of cylinders 15 at equal intervals on the same circumference centered on the rotary shaft 12 and whose axes are parallel to the rotary shaft 12, and pistons 16 slide on the cylinders 15, respectively. Freely housed. The bottom surface of the cylinder block 14 is
It contacts the valve plate 17 fixed to the side wall 11a of the housing 11.

A ring plate 19 is provided facing the cylinder block 14 in a state of being inclined with respect to the axis of the cylinder block 14, and the ring plate 19 is provided on the inclined surface 20a of the support base 20 provided on the side wall 11b of the housing 11. Movement in the radial direction is regulated by a cylindrical bearing ring 22 that is in contact with the back surface and is arranged around the back surface. As shown in FIG. 3, a plurality of shoes 23 corresponding to the piston 16 are held on the surface of the ring plate 19 by spherical contact, and the piston 1 is held through these shoes 23.
Contact 6

The shoe 23 has a shape obtained by dividing a sphere into halves, and the spherical surface portion 23a is housed in a hemispherical recess 19a formed in the ring plate 19, and the smooth surface 23b is formed in the piston 16.
It comes into surface contact with the contact surface 16a formed in the above. The contact surface 16a of the piston 16 is a plane formed at the tip of the piston 16 perpendicularly to its axis, and the pressing force of the piston 16 is applied to the shoe 23.
To the ring plate 19 via.

The diameter of the shoe 23 is slightly larger than the diameter of the piston 16, and when the piston 16 is displaced relative to the shoe 23 in the radial direction with the rotation of the cylinder block 14, the piston 16 moves to the ring plate 19.
It does not come into contact with the concave portion 19a.

The center of the ring plate 19 and the tip of the rotary shaft 12 are connected by a universal joint 25, and the rotary shaft 1
The rotation of 2 causes the ring plate 19 to rotate synchronously in the same direction. The universal joint 25 includes a U-shaped connecting tube 25a connected to the rotary shaft 12 by a pin 26a and a ring plate 19
The central cylindrical portion 19c of the U is connected to a U-shaped connecting cylinder 25b by a pin 26b so as to be rotatable by a connecting shaft 25e having mutually orthogonal shaft portions 25c and 25d. The rotation is smoothly transmitted to the ring plate 19 present.

The cylinder 15 is provided with a spring 28 for urging the bottomed cylindrical piston 16 in the extending direction so that the piston 16 is constantly brought into contact with the ring plate 19 via the shoe 23. The cylinder 15 selectively communicates with a suction passage and a discharge passage (not shown) via a pair of ports 17a provided on the valve plate 17 in accordance with the rotational position of the cylinder block 14.

Further, the through passage 16 formed in the piston 16
b through the smooth surface 23b of the shoe 23 and the contact surface 16a.
A part of the fluid in the cylinder 15 is guided to the static pressure bearing surface 29a formed on the contact surface between the contact surface and the contact surface, and the contact friction is reduced.
Further, due to the through passage 23c formed in the shoe 23, the spherical surface 23a of the shoe 23 and the recess 19a of the ring plate 19 are formed.
A part of the fluid is guided for lubrication to the hydrostatic bearing surface 29b formed on the contact surface with the outer peripheral surface of the ring plate 19 and the bearing through branching through passages 19d and 19e formed on the ring plate 19. The hydrostatic bearing surface 29c formed between the ring 22 and the hydrostatic bearing surface 2 formed between the back surface of the ring plate 19 and the inclined surface 20a of the support base 20.
The lubricating fluid is also introduced into 9d.

With the above construction, the operation will be described below. When the rotating shaft 12 is rotated by a motor (not shown), the cylinder block 14 is integrally rotated, and at the same time, the ring plate 19 is synchronously rotated via the universal joint 25.

In the process in which the cylinder block 14 and the shoe 23 are separated from each other due to this rotation, the piston 16 is pushed out by the spring 28 and extends, and the fluid is sucked into the cylinder 15 through one port 17a. To be done.
Next, in the process of approaching the cylinder block 14 and the shoe 23, the piston 16 is compressed and the cylinder 15
The fluid inside is discharged from the other port 17a.

In this way, as the cylinder block 14 rotates, each piston 16 expands and contracts while coming into contact with the ring plate 19 via the shoe 23, repeating suction and discharge of fluid to the cylinder 15 and functioning as an axial piston pump. To do.

At this time, as shown in FIG. 4, the fluid pressure corresponding to the load connected to the discharge passage is generated in the cylinder 15 as the fluid is discharged from the cylinder 15. The pressing force F10 that accompanies this fluid pressure acts on the piston 16, and this extends to the smooth surface 23b of the shoe 23 as F14. F14 applied to the shoe 23 is supported by the ring plate 19 as a force F11 in the rotation axis direction and a force F12 in the direction perpendicular thereto. The shoe 23 and the piston 16 have a smooth surface 2 perpendicular to the axis of the piston 16.
Since it is divided into 3b and the contact surface 16a and is in surface contact, no reaction force is exerted on the piston 16 from the shoe 23 in the direction perpendicular to the axial center of the shoe (when the frictional force on the contact surface is ignored). ), The surface pressure of the sliding surface of the piston 16 with respect to the cylinder 15 becomes extremely low. When the piston 16 is not divided by a plane perpendicular to the axial center of the piston 16, a lateral force is generated in the piston 16 due to a reaction force corresponding to the inclination angle of the ring plate 19,
Although the sliding friction between the cylinder 15 and the cylinder 15 is large, the force in the direction perpendicular to the axis is divided by the surface perpendicular to the axis as described above, and thus the force in the direction perpendicular to the axis is the contact surface between the smooth surface 23b and the contact surface 16a. It only acts as a frictional force.

By the way, as also shown in FIG. 3, the force F16 acting on the ring plate 19 by the reaction of the force F12 in the direction perpendicular to the rotation axis of the ring plate 19 is generated in all the cylinders 15 in the discharge stroke, As a result of these, F1
Yields 7. This F17 can be decomposed into a radial force F18 and a circumferential force F19, and a rotational torque is generated in the ring plate 19 by this F19. Therefore, in order to perform the pumping action, it is necessary to rotate the ring plate 19 in synchronization with the cylinder block 14 against this rotational torque.

In this case, since the piston 16 is divided from the shoe 23 in a plane perpendicular to its axis, the rotational torque of the cylinder block 14 cannot be transmitted to the ring plate 19 via the piston 16. However, the cylinder block 14 and the ring plate 19 are connected by the universal joint 25 as a rotational torque transmission mechanism, and the ring plate 19 can be synchronously rotated. Conversely speaking, since torque is transmitted by the universal joint 25, it is possible to prevent lateral force in the rotational tangential direction from acting on the piston 16.

As a result, the lateral force acting on the piston 16 is greatly reduced, and the sliding surface pressure on the piston 16 and the cylinder 15 is significantly reduced. Therefore, the problem of seizure due to the sliding of the piston 16 and the cylinder 15 is solved, and it becomes possible to increase the pressure and speed of the pump. Also,
As the amount of heat generated by sliding friction decreases, the sliding gap between the piston 16 and the cylinder 15 can be reduced, the amount of fluid leakage can be reduced, and the pump volume efficiency can be improved. Since the lateral force applied to the piston 16 is significantly reduced, the required fitting length of the piston 16 with the cylinder 15 can be shortened. Therefore, downsizing by shortening the axial direction of the piston 16 is also possible.

On the other hand, since the lateral force of the piston 16 is not generated in the cylinder block 14, only the acting force F13 for pressing the valve plate 17 in the rotational axis direction is generated by the fluid pressure in the cylinder 15. Therefore, the cylinder block 1
4 is simplified, the cylinder block 14 and the valve plate 17
Since the fluid film on the sliding surface of and has a hydrostatic bearing effect, it is easy to secure an appropriate sliding surface pressure, keep the sliding surface in a good lubricating state, and prevent seizure or excessive leakage. Can be avoided.

The static pressure bearing surface 29c between the ring plate 19 and the bearing ring 22 and the ring plate 1
A part of the fluid is guided from the inside of the cylinder 15 to the hydrostatic bearing surface 29d between the support 9 and the support table 20 for lubrication, so that the ring plate 19 can be smoothly rotated. Further, by introducing the working fluid to the static pressure bearing surface 29a formed between the piston 16 and the shoe 23 and the static pressure bearing surface 29b between the shoe 23 and the ring plate 19, smooth contact between the sliding contact surfaces can be achieved. Guarantees sliding and effectively prevents seizure and uneven wear.

However, a hydrostatic bearing 29c for supporting the radial load between the ring plate 19 and the bearing ring 22.
Has a strict requirement for machining accuracy in the radial direction, so it can be used as a dynamic pressure bearing. In this case, fluid leakage loss is small and machining is easy. Of course, these hydrostatic bearings,
Instead of the dynamic pressure bearing, it can be supported by a roller bearing.

Further, since the shoe 23 is formed in a hemispherical shape, the shoe 23 can be easily manufactured, and the piston 16 that comes into contact with the shoe 23 does not have the conventional spherical portion at the tip, so that the structure is simple and the productivity is also high. improves.

Since the universal joint 25 for transmitting the rotation from the rotary shaft 12 to the ring plate 19 is connected to the rotary shaft 12 at the center of the ring plate 19, the space for arranging the universal joint 25 is small and it is compact. be able to.

Another embodiment will be described below with reference to FIG.
In the embodiment shown in FIG. 6, the cylinder block 14 and the ring plate 19 are connected to each other by a universal joint 30 so as to rotate them in synchronism with each other.

The universal joint 30 as a rotation transmission mechanism has a connecting ring 30a arranged outside the ring plate 19,
With respect to the connecting ring 30a, a pair of shafts 30b extending diametrically from the ring plate 19 and a pair of shafts 30c extending diametrically from the outer circumference of the cylinder block 14.
And are connected so as to be orthogonal to each other on the same circumference.

By arranging the universal joint 30 on the outer side in this way, the torque transmission capacity is increased and the pump output can be increased.

The embodiment of FIG. 7 is a cylinder block 1
4 and the ring plate 19 as a rotation transmission mechanism that rotates the ring plate 19 and the ring plate 19 in synchronization.
The helical teeth 31a and 31b meshing with each other are formed at the center of the ring plate, and the helical teeth 31a and 31b partially mesh with each other in a state where their centers of rotation coincide with each other, and the rotation of the rotary shaft 12 is rotated by the ring plate. Propagate to 19.

The helical teeth 31a, 3 that mesh with each other in this way
When the rotation is transmitted by 1b, the cylinder block 14 and the ring plate 19 rotate exactly the same without causing a phase difference in rotation. Universal joint 25, 30 described above
When the rotation is transmitted by, the average values of the rotation angle and the rotation speed are equal, but since the rotation is transmitted by two orthogonal axes, 1
A deviation occurs in two cycles per rotation. The reciprocating motion of the piston 16 basically changes in a sine wave shape. However, if the rotation fluctuation occurs in the middle in this way, the behavior of the piston 16 becomes complicated, and the high-frequency pulsation is superimposed on the sine wave discharge pulsation characteristic. Further, vibration is generated in the piston 16, the shoe 23, the ring plate 19, etc. due to inertia.

However, in the case where the helical teeth 31a and 31b are connected in this manner, the rotational phase does not occur, and the discharge pulsation and vibration can be suppressed.

The embodiment of FIG. 8 is a cylinder block 1
4 and the outer circumference of the ring plate 19 with helical teeth 32a, 32
b are formed so that they are partially meshed with each other. In this case, since the outer peripheral portions are engaged with each other, a larger rotational torque can be transmitted and a larger capacity of the pump can be accommodated as compared with the embodiment of FIG. Further, the rotary shaft 12 penetrates the center of the ring plate 19 and
Since the bearings 13a and 11b support the rotary shaft 12 in a double-supported state via the bearings 13a and 13b, the support rigidity of the rotary shaft 12 is increased, and the capacity can be increased.

In the embodiment shown in FIG. 9, as a rotation transmission mechanism, spline holes 34a and 34b are formed at the centers of rotation of the cylinder block 14 and the ring plate 19, respectively, and teeth 33a meshing with these spline holes 34a and 34b. , 33b at both ends by the toothed shaft 33,
The cylinder block 14 and the ring plate 19 are synchronously rotated.

In this case, since the cylinder block 14 and the ring plate 19 can be connected to each other at the center of rotation, the structure is compact, and the cylinder block 14 and the ring plate 19 are the same without any phase difference. While being rotated, the moment due to the separation force generated between the oblique teeth due to the rotation transmission as in the embodiment of FIG. 7 or FIG. 8 is not applied to the cylinder block 14, and the cylinder block 14 is rotated. The behavior of can be stabilized.
Further, if each tooth surface of both toothed shafts 33 is formed in an arc shape (barrel shape), even if the angle at which the cylinder block 14 and the ring plate 19 intersect changes, it is possible to follow freely, so it is variable. It can also be applied to displacement pumps.

In the embodiment shown in FIGS. 10 and 11, the inclination of the ring plate 19 is changed to variably control the pump discharge amount. The support base 20 is separated from the housing 11, and the ring plate 19 is moved in the radial direction. The pair of extending trunnion shafts 35a and 35b are tiltably supported with respect to the housing 11.

By changing the inclination angle of the ring plate 19 via the support base 20 in this way, the piston 16 makes a stroke when the rotational axes of the cylinder block 14 and the ring plate 19 are on the same extension. The discharge amount becomes zero and the discharge amount becomes zero, but the stroke amount increases as the inclination angle increases, and the discharge amount increases. A mechanism for tilting and driving the support base 20 is not shown.

As the rotation transmission mechanism for synchronously rotating the cylinder block 14 and the ring plate 19, the universal joint 25 capable of responding to the change of the inclination angle of the ring plate 19 is provided, but the spline holes 34a and 34b and both teeth are provided. It can also be configured with the attached shaft 33.

In the embodiment shown in FIG. 12, the rear surface 20c of the support 20 is formed into a cylindrical shape, and the side wall 11 of the housing 11 is formed.
Similarly, a cylindrical inner peripheral surface 11c is formed on b, and the support base 2
It supports 0 freely and freely. The tilt angle of the support base 20 is controlled by a drive mechanism (not shown).

In this cradle type, the ring plate 1
Since the load received by the support base 20 via 9 is supported by the inner peripheral surface 11c of the housing 11 having a large contact area, the surface pressure is reduced and the durability is enhanced. It should be noted that it is of course possible to use a spherical surface instead of the cylindrical surface.

The above-mentioned embodiments are all for a swash plate type radial piston pump, but the following is an embodiment for a swash-shaft type radial piston pump. The swash plate type and the swash axis type have essentially the same operating characteristics, and the swash axis type is different in that the rotary shaft 12 is inclined with respect to the rotary shaft center of the cylinder block 14.

In the embodiment of FIG. 13, the rotary shaft 12
Penetrates the side wall 11a of the housing 11 and is connected to the center of the ring plate 19 by a spline portion 18a, so that the rotary shaft 12 and the ring plate 19 rotate integrally. On the other hand, the cylinder block 14 has a housing 11
Is rotatably supported by a support shaft 40 protruding from the side wall 11b of the cylinder block, and the center portion of the ring plate 19 on the cylinder block side and the tip portion of the cylinder block 14 on the ring plate side are connected to each other by a universal joint 25. The plate 19 and the cylinder block 14 are designed to rotate synchronously. The tip of the rotary shaft 12 and the center of the cylinder block 14 may be connected by the universal joint 25.

The ring plate 19 is slidably supported by the bearing plate 42 provided on the support portion 41 formed on the side wall 11a and the bearing ring 22 on the outer periphery thereof.

The contact surface between the piston 16 and the shoe 23 is the same as that of each of the above-described embodiments, such that the contact surface of the piston 16 is formed perpendicularly to the axial center of the piston 16.

As described above, also in the oblique shaft type axial piston pump, it is possible to prevent the lateral force from being generated in the piston 16, reduce the sliding surface pressure, and prevent the seizure etc. It is possible to realize high pressure, stabilize the behavior of the cylinder block 14, and reduce the leakage of the working fluid between the valve plate 17.

In the case of this oblique shaft type axial piston pump, the torque required to rotate the cylinder block 14 is smaller than that of the ring plate 19 on which the component of the discharge reaction force in the rotational direction acts. , The transmission torque applied to the universal joint 25 as the rotation transmission mechanism is reduced,
The size and weight of the universal joint 25 can be reduced.

In the embodiment shown in FIG. 14, as a rotation transmission mechanism, spiral teeth 31a and 31 are provided at the abutting ends of the rotary shaft 12 and the center of the cylinder block 14, respectively.
b is provided, and the ring plate 19 and the cylinder block 14 are synchronously rotated by their engagement.

Further, in the embodiment of FIG. 15, the ring plate 19 and the cylinder block 14 are formed with oblique teeth 32a and 32b on their outer peripheral portions, respectively.
Is transmitted to the cylinder block 14.

Further, in the embodiment shown in FIG. 16, the spline hole 34a formed in the center of the ring plate 19 and the spline hole 34b formed in the center of the cylinder block 14 are connected by the shaft 33 with both teeth. The ring plate 19 and the cylinder block 14 are synchronously rotated.

In this way, the rotation of the ring plate 19 and the cylinder block 14 coincides with each other by transmitting the rotation by the helical teeth 31a, 31b or 32a, 32b, or the shaft 33 with both teeth, and pump discharge pulsation and Vibration can be reduced. In addition, if the rotation transmission mechanism is located at the center of rotation, the size and weight can be reduced by reducing the installation space.

In the embodiment shown in FIGS. 17 and 18, the ring plate 19 is used to variably control the discharge amount of the pump.
The inclination angle of the cylinder block 14 with respect to is changed.

The cylinder block 14 is a housing 11
Is supported by a cylinder block support 50 separated from. That is, the support shaft 50a is integrally formed at the center of the cylinder block support 50 so as to project therein, and supports the cylinder block 14 rotatably there. The cylinder block support 50 is tiltably supported by the housing 11 by a pair of trunnion shafts 50b passing through the center of rotation of the cylinder block 14, and the cylinder block support 50 has a suction port communicating with the port 17a of the valve plate 17 inside. Passage 5
1 and the discharge passage 52 are formed so as to penetrate therethrough and communicate with an external hydraulic passage (not shown).

In this way, by tilting the cylinder block support 50 with the trunnion shaft 50b as a fulcrum, the cylinder block 14 also tilts integrally, and the tilt angle with the ring plate 19 changes. Therefore, the stroke amount of the piston 16 changes, and the pump discharge amount can be variably controlled.

In the embodiment shown in FIGS. 19 and 20, a cylindrical rear surface 50c is formed on the cylinder block support 50, and an inner peripheral surface 11d which is in cylindrical contact with the rear surface 50c is formed on the housing 11. Thus, the load applied to the cylinder block 14 is supported by the inner peripheral surface 11d of the housing 11. It should be noted that the suction passage 51 and the discharge passage 52 have a certain length in the sliding direction of the cylinder block support 50 and are opened on the inner peripheral surface 11d, so that even if the cylinder block support 50 moves, Try to maintain communication at all times.

In this case as well, a variable displacement type pump whose discharge amount changes according to the inclination angle of the cylinder block 14 can be used.

Next, the embodiments shown in FIGS. 21 to 25 show different examples of the rotation transmission mechanism.
First, FIG. 21 shows a pin 26a passing through the center of rotation of the rotary shaft 12.
The one end and the other end are connected to the rotary shaft 12 and the ring plate 19 by a coil spring 55 of high rigidity supported by a pin 26b passing through the center of rotation of the ring plate 19. The spring 55 maintains the synchronous rotation of the cylinder block 14 and the ring plate 19 by setting the torsional rigidity higher than the bending rigidity. By using the high-rigidity spring 55 as described above, the structure is simplified and the production cost is reduced.

The ring plate 19 is replaced by the spring 5
Instead of indirectly connecting the cylinder block 14 to the cylinder block 14 by means of 5, the rotation shaft 12 may be shortened and the ring plate 19 and the cylinder block 14 may be directly connected. Is.

In FIG. 22, the ring plate 19 and the cylinder block 14 are directly or indirectly connected by a metal bellows 56 instead of the spring 55.
The same action and effect as in FIG. 21 are produced.

Further, in FIG. 23, the ring plate 19 and the cylinder block 14 are directly or indirectly connected to each other by the twisted flexible shaft 57. A flexible shaft is formed by combining a number of wire rods and has higher rigidity in the torsional direction than bending rigidity. Also in this case, FIG.
It produces the same action and effect as.

24 and 25 show a cylindrical flexure shaft 58.
Thus, the ring plate 19 and the cylinder block 14 are directly or indirectly connected to each other.

This is one in which slits 58a and 58b are alternately formed in multiple steps from the outer peripheral surface of a cylindrical body so that the bending rigidity is low and a predetermined torsional rigidity is maintained, as in FIG. It produces various actions and effects.

Although each of the above examples is applied to the swash plate type axial piston pump, it goes without saying that the same can be applied to the swash shaft type axial piston pump.

Next, the embodiment shown in FIGS. 26 to 30 will be described.
The structure shown in FIG. 26 basically corresponds to the structure of the swash plate type axial piston pump of FIG. Instead of supporting the bearing ring 22 in the center hole 20c of the support base 20,
The central protruding portion 19h of the ring plate 19 is fitted, and a bearing 20b is interposed on this fitting surface, thereby supporting the radial load applied to the ring plate 19.

A sliding bearing, a rolling bearing or the like is used as the bearing 20b.
When h is fitted in the center hole 20c of the support 20, the ring plate 19 can be easily assembled to the support 20 and the productivity is improved.

27 corresponds to the configuration of the oblique shaft type axial piston pump shown in FIG. 13, and the outer circumference of the projection 19h of the ring plate 19 serves as a bearing 13 for supporting the rotary shaft 12 in the housing 11. The ring plate 1 is rotatably supported by the bearing 20b on the same row.
The load of 9 in the radial direction is supported.

28, the rotary shaft 12 and the ring plate 19 are integrally formed, and the bearing 13 of the rotary shaft 12 simultaneously supports the radial load applied to the ring plate 19. .

Thus, the rotating shaft 12 and the ring plate 1
When 9 is integrally formed of the same member, the number of parts is reduced, and the assembling of these parts is simplified and the productivity is improved.

In FIG. 29, the outer peripheral surface of the ring plate 19 is supported by a hydrostatic bearing 60.
0 indicates the ring plate 1 on the inner peripheral surface 11f of the housing 11.
The outer peripheral surface of 9 is brought into sliding contact, and the hydrostatic bearing 6 faces the sliding surface.
0 pocket 11d is formed, and hydraulic oil is supplied to this pocket 11d via a passage 11e provided in the cross section of the housing 11.

In this case, as shown in FIG. 30, the static pressure pocket 1 is arranged so as to oppose the radial load acting on the ring plate 19 via the piston shoes 23.
The position of 1d is determined, and is preferably formed to face the outer peripheral position of the ring plate 19 facing the piston 16 which is the bottom dead center among the plurality of pistons 16, and the radial direction of the reaction force by each piston 16 It is set to generate a static pressure that opposes the combined force of.

When the hydrostatic bearing 60 is constructed directly on the inner circumference of the housing 11 in this way, the structure including the hydraulic oil supply path is improved as compared with the case where it is provided on the outer circumference of the support base 20. It is simple and the production cost can be reduced.

Although all of the above embodiments show the present invention applied as an axial piston pump, it is obvious that the same can be applied to an axial piston motor.

[0143]

According to the first aspect of the present invention, the cylinder block accommodating the piston and the ring member with which the piston contacts via the shoe are connected via a rotation transmission mechanism,
The rotation torque difference between the cylinder block and the ring member is received by the rotation transmission mechanism, while the piston and the shoe are separated on the plane orthogonal to the sliding axis of the piston, and the piston axis is included in the reaction force from the ring member. Due to the existence of the separation surface, the component force in the direction orthogonal to is almost not transmitted to the piston.As a result, the component force orthogonal to the piston reciprocating direction is not generated between the piston and the cylinder block. The sliding surface pressure is reduced, seizure can be avoided, the pump and motor can be operated at higher speed and pressure, or the piston can be shortened in the axial direction to achieve miniaturization, while the acting force of the cylinder block is in the axial direction. Since only the components are included, the sliding surface pressure between the cylinder block and the valve plate can be easily optimized, and seizure and fluid leakage can be prevented.

According to the second invention, the cylinder block is directly connected to the rotary shaft member, the ring member is rotated via the rotation transmission mechanism, and operates as a swash plate type axial piston pump / motor.

According to the third aspect of the present invention, the ring member is directly connected to the rotary shaft member, and the cylinder block is rotated synchronously with the ring member via the rotation transmission mechanism to operate as an oblique shaft type axial piston pump / motor. To do.

According to the fourth aspect of the present invention, the spring for biasing the piston in the extending direction keeps the piston and the shoe in contact with each other even when the fluid pressure acting on the piston is small, thereby achieving good operability. Can be secured.

According to the fifth invention, the ring member does not move in the radial direction but rotates while slidingly contacting the inclined surface of the support base provided in the housing, and operates with the flow rate characteristic according to the angle of the inclined surface. To do.

According to the sixth invention, the load in the radial direction applied to the ring member is supported by the bearing ring, and the sliding contact rotation is performed stably without deviating from the support base.

According to the seventh aspect of the invention, the radial load applied to the ring member is supported by the bearing ring provided in the supporting portion, and the sliding contact rotation is performed stably without departing from the supporting portion.

According to the eighth invention, the radial load of the ring member is supported by the hydrostatic bearing formed on the fitting surface of the bearing ring and the ring member, and the ring member can be smoothly rotated.

According to the ninth aspect of the invention, the radial load of the ring member is supported and smoothly rotated by the dynamic pressure bearing or the roller bearing formed on the fitting surface of the bearing ring and the ring member.

According to the tenth aspect of the present invention, the radial load applied to the ring member is supported by the static pressure bearing on the inner peripheral surface of the housing for smooth rotation, while the structure of the static pressure bearing is simplified. Production costs can also be reduced.

According to the eleventh aspect of the invention, the load on the ring member in the radial direction is supported by the bearing on the inner peripheral surface of the support base,
It can be rotated smoothly. Further, the ring member can be easily attached to the support base.

According to the twelfth aspect, the load in the radial direction applied to the ring member is directly supported by the housing via the bearing, so that the ring member can be smoothly rotated.

According to the thirteenth aspect of the invention, since the universal joint for connecting the rotation center of the cylinder block and the rotation center of the ring member is provided as the rotation transmission mechanism, it can be compactly stored in a small space.

According to the fourteenth aspect of the invention, since the universal joint for connecting the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member is provided as the rotation transmitting mechanism, a large torque can be transmitted and a large capacity is achieved. Applicable to

According to the fifteenth aspect of the present invention, the rotation transmission mechanism is formed with the oblique teeth that mesh with each other at the rotation center of the cylinder block and the rotation center of the ring member. There is no deviation due to the rotation angle, and operating characteristics with less rotational pulsation and vibration.

According to the sixteenth aspect of the invention, as the rotation transmitting mechanism, since the spiral teeth meshing with each other are formed on the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member, the rotation angle of the rotation phase between the cylinder block and the ring member is increased. There is no deviation due to
While operating characteristics with less rotation pulsation and vibration can be achieved, large torque can be transmitted, and it can be applied to large capacity.

According to the seventeenth aspect of the invention, as the rotation transmission mechanism, the cylinder block and the spline hole formed at each rotation center of the ring member are connected by both toothed shafts, so that the cylinder block and the ring member rotate. The phase does not deviate due to the rotation angle, and operating characteristics with less rotational pulsation and vibration can be achieved, while it can be compactly arranged in a small space.

According to the eighteenth aspect of the invention, since the rotary shaft member penetrates the center of the ring member and is rotatably supported by the housing at both ends, it is possible to support both ends by
The support strength of the rotary shaft member can be increased.

According to the nineteenth invention, since the cylinder block and the ring member are connected by the highly rigid spring as the rotation transmission mechanism, the cylinder block and the ring member are crossed while suppressing the rotational phase to a minimum. The rotary motion can be smoothly transmitted about the axis of rotation, and the structure is simple, so that the production cost can be reduced.

According to the twentieth aspect, since the cylinder block and the ring member are connected by the bellows having a high rigidity as the rotation transmission mechanism, the rotation phase of the cylinder block and the ring member is suppressed to the minimum and the intersection is achieved. The rotary motion can be smoothly transmitted about the rotating shaft center, the structure can be simplified, and the production cost can be reduced.

According to the twenty-first aspect of the invention, since the cylinder block and the ring member are connected by the twisted flexure shaft serving as the rotation transmission mechanism, the rotation phase of the cylinder block and the ring member is suppressed to the minimum and the intersection is achieved. The rotary motion can be smoothly transmitted about the rotating shaft center, the structure can be simplified, and the production cost can be reduced.

According to the twenty-second aspect, since the cylinder block and the ring member are connected by the smooth type flexible shaft as the rotation transmitting mechanism, the rotation phase of the cylinder block and the ring member is suppressed to the minimum and the intersection is achieved. The rotary motion can be transmitted smoothly about the axis of rotation, and the structure can be simplified and the production cost can be reduced.

According to the twenty-third aspect, the support base is tiltable, and the variable stroke characteristic can be obtained by adjusting the effective stroke of the piston abutting the ring member according to the inclination angle of the support base. .

According to the twenty-fourth aspect, since the rear surface of the supporting table is in contact with the housing in the cylindrical surface or the spherical surface, the reaction force received by the supporting table through the ring member can be supported by the housing, and the durability strength is enhanced. .

According to the twenty-fifth aspect, since the cylinder block is tiltably supported, the variable displacement characteristic can be obtained by adjusting the effective stroke of the piston according to the tilt angle of the cylinder block. .

According to the twenty-sixth aspect, the rear surface of the cylinder block support member comes into contact with the housing in a cylindrical surface or a spherical surface, and the reaction force received by the cylinder block can be supported by the housing, and the durability strength can be enhanced.

According to the twenty-seventh invention, the shape of the shoe interposed between the ring member and the piston is a substantially half-sphere, the structure is simple, and the productivity is good.

According to the twenty-eighth aspect, the lubricating fluid is introduced into the contact surface between the shoe and the piston, and a good lubricating function can always be maintained.

According to the twenty-ninth aspect of the invention, the lubricating fluid introduced into the contact surface between the shoe and the piston is introduced into the spherical contact surface between the shoe and the ring member. Lubricity is maintained.

According to the thirtieth aspect, the lubricating fluid introduced into the spherical contact surface between the shoe and the ring member is further introduced into the sliding contact surface between the ring member and the bearing ring. Also maintains good lubricity.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a transverse sectional view of the same.

FIG. 3 is an explanatory diagram similarly seen from the surface of the ring plate.

FIG. 4 is an explanatory view showing an acting force similarly applied to the piston.

FIG. 5 is a vertical cross-sectional view showing a second embodiment.

FIG. 6 is a cross-sectional view of the same.

FIG. 7 is a vertical cross-sectional view showing a third embodiment.

FIG. 8 is a vertical sectional view showing a fourth embodiment.

FIG. 9 is a vertical sectional view showing a fifth embodiment.

FIG. 10 is a vertical sectional view showing a sixth embodiment.

FIG. 11 is a transverse sectional view of the same.

FIG. 12 is a vertical sectional view showing a seventh embodiment.

FIG. 13 is a vertical sectional view showing an eighth embodiment.

FIG. 14 is a vertical sectional view showing a ninth embodiment.

FIG. 15 is a vertical sectional view showing a tenth embodiment.

FIG. 16 is a vertical sectional view showing an eleventh embodiment.

FIG. 17 is a vertical sectional view showing a twelfth embodiment.

FIG. 18 is a cross-sectional view of the same.

FIG. 19 is a vertical sectional view showing a thirteenth embodiment.

FIG. 20 is a cross-sectional view of the same.

FIG. 21 is a vertical sectional view showing a fourteenth embodiment.

FIG. 22 is a vertical sectional view showing a fifteenth embodiment.

FIG. 23 is a vertical sectional view showing a sixteenth embodiment.

FIG. 24 is a vertical sectional view showing a seventeenth embodiment.

FIG. 25 is a sectional view taken along line AA of the same.

FIG. 26 is a vertical sectional view showing an eighteenth embodiment.

FIG. 27 is a vertical sectional view showing a nineteenth embodiment.

FIG. 28 is a vertical sectional view showing a twentieth embodiment.

FIG. 29 is a vertical sectional view showing a twenty-first embodiment.

FIG. 30 is an explanatory view of the ring plate of the same.

FIG. 31 is a vertical sectional view of a conventional example.

FIG. 32 is an explanatory diagram showing an acting force similarly applied to the piston.

[Explanation of symbols]

 11 Hounsing 12 Rotating Shaft 14 Cylinder Block 15 Cylinder 16 Piston 17 Valve Plate 19 Ring Plate 20 Support Stand 22 Bearing Ring 23 Shoe 25 Universal Joint 29a Hydrostatic Bearing Surface 29b Hydrostatic Bearing Surface 29c Hydrostatic Bearing Surface 29d Hydrostatic Bearing Surface 30 Universal joint 31a, 31b Spiral tooth 32a, 32b Spiral tooth 33 Shaft with both teeth 41 Support part 50 Cylinder block support 55 Spring 56 Bellows 57 Strand flexure shaft 58 Cylindrical flexure shaft 60 Hydrostatic bearing

Claims (30)

[Claims] 1. A cylinder block rotatably supported around an axis, a plurality of pistons reciprocally accommodated on a concentric circle of a rotation axis of the cylinder block, and a rotation axis center of the cylinder block. In an axial piston pump / motor including a ring member that is relatively inclined and with which the tip of the piston abuts, and a rotating shaft member that rotates in synchronization with the cylinder block, a shoe that makes spherical contact with the ring member, and the piston A contact surface provided at the tip of the shaft and orthogonal to the axis, a smooth surface provided on the shoe in surface contact with the contact surface, and a rotation transmission mechanism for synchronously rotating the cylinder block and the ring member. Axial piston pump / motor characterized by 2. A cylinder block rotatably supported about an axis, a plurality of pistons reciprocally accommodated on a concentric circle of a rotation axis of the cylinder block, and a rotation axis center of the cylinder block. In an axial piston pump / motor provided with a ring member that is relatively inclined and with which the tip of the piston abuts, and a rotary shaft member that is coaxially connected to the cylinder block and that rotates integrally, The shoe that makes spherical contact, the contact surface that is orthogonal to the axis provided at the tip of the piston, the smooth surface that is provided on the shoe that makes surface contact with the contact surface, the cylinder block and the ring member are synchronized. An axial piston pump / motor having a rotation transmission mechanism for rotating. 3. A cylinder block rotatably supported about an axis, a plurality of pistons reciprocally accommodated on a concentric circle of a rotation axis of the cylinder block, and a rotation axis center of the cylinder block. An axial piston pump / motor comprising: a ring member that is relatively inclined and is in contact with the tip of the piston; and a rotary shaft member that is coaxially connected to the ring member and that rotates in synchronization with a cylinder block. A shoe that is in spherical contact with, a contact surface that is orthogonal to the axis provided at the tip of the piston, a smooth surface that is provided on the shoe that makes surface contact with the contact surface, the cylinder block and the ring member. An axial piston pump / motor comprising: a rotation transmission mechanism for synchronous rotation. 4. The axial piston pump / motor according to claim 1, further comprising a spring for urging the piston in an extending direction so as to constantly contact the shoe. 5. The axial piston pump / motor according to claim 2, wherein one surface of the ring member is in sliding contact with an inclined surface of a support table provided in the housing and is constrained in a radial direction. 6. The axial piston pump / motor according to claim 5, wherein the bearing ring mounted on the support is slidably fitted on the outer periphery of the ring member. 7. The ring member slidably contacts a support portion provided on the housing, and a bearing ring attached to the support portion is slidably fitted to the outer periphery of the ring member. Axial piston pump motor. 8. The axial piston pump / motor according to claim 6, wherein a static pressure bearing is formed on a fitting surface between the bearing ring and the ring member. 9. The axial piston pump / motor according to claim 6, wherein a dynamic pressure bearing or a roller bearing is formed on a fitting surface between the bearing ring and the ring member. 10. An outer peripheral surface of the ring member is supported by an inner peripheral surface of a part of the housing, and a static pressure bearing is configured on the support surface, and the static pressure bearing is provided with a passage formed in a cross section of the housing. 5. The axial piston pump / motor according to claim 1, wherein the working oil is introduced. 11. The axial piston pump / motor according to claim 5, wherein a part of the ring member is rotatably supported by an inner peripheral surface of the support base via a bearing. 12. The axial piston according to claim 1, wherein a part of the ring member is rotatably supported by a part of an inner peripheral surface of the housing via a bearing. Pumps and motors. 13. The rotation transmission mechanism includes a universal joint that connects the rotation center of the cylinder block and the rotation center of the ring member with two axes that are orthogonal to each other. An axial piston pump / motor according to any one of 1. 14. The rotation transmission mechanism according to claim 1, further comprising a universal joint that connects the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member with two axes orthogonal to each other. The axial piston pump / motor according to any one of the above. 15. The rotation transmitting mechanism is characterized in that a helical tooth is formed at the abutting end of the rotation center of the cylinder block and the rotation center of the ring member so as to mesh with each other. An axial piston pump / motor according to any one of 1. 16. The rotation transmission mechanism according to claim 1, wherein spiral teeth that mesh with each other are formed at the abutting ends of the outer peripheral portion of the cylinder block and the outer peripheral portion of the ring member. The axial piston pump / motor described in one. 17. The rotation transmission mechanism includes a spline hole formed in the center of rotation of the cylinder block, and a toothed shaft that meshes with the spline hole formed in the center of rotation of the ring member. Claim 1 to
The axial piston pump / motor according to any one of items 1 to 12. 18. The rotating shaft member penetrates the center of the ring member in a non-interfering state, and both ends of the rotating shaft member are rotatably supported by the housing.
The axial piston pump / motor according to 4 or 16. 19. The high-rigidity spring that directly or indirectly connects the rotation center of the cylinder block and the rotation center of the ring member as the rotation transmission mechanism. The axial piston pump / motor according to any one of the above. 20. The high-rigidity bellows, which directly or indirectly connects the rotation center of the cylinder block and the rotation center of the ring member, as the rotation transmission mechanism. The axial piston pump / motor according to any one of the above. 21. The stranded wire bending shaft that directly or indirectly connects the rotation center of the cylinder block and the rotation center of the ring member as the rotation transmission mechanism. The axial piston pump / motor according to any one of the above. 22. A cylindrical flexible shaft that directly or indirectly connects the rotation center portion of the cylinder block and the rotation center portion of the ring member as the rotation transmission mechanism. The axial piston pump / motor according to any one of the above. 23. The axial piston pump according to claim 5, wherein the support base is supported by the housing via a support shaft such that an inclined surface with which the ring member is in sliding contact is tiltable. ·motor. 24. The back surface of the supporting table is in contact with the housing as a cylindrical surface or a spherical surface so that the inclined surface of the supporting table with which the ring member slides can be tilted. Axial piston pump / motor. 25. The axial piston pump / motor according to claim 3, wherein the cylinder block is supported by the housing so as to be tiltable with respect to the ring member via a support shaft. 26. The axial according to claim 3, wherein the rear surface of the cylinder block support member is in contact with the housing by a cylindrical surface or a spherical surface so that the cylinder block can be tilted with respect to the ring member. Piston pump / motor. 27. The shoe is formed into a substantially hemispherical sphere, and its spherical surface is in spherical contact with a hemispherical recess formed in a ring member,
The axial piston pump / motor according to any one of claims 1 to 26, characterized in that its smooth surface is in surface contact with the contact surface of the piston. 28. The axial piston pump / motor according to claim 27, wherein a lubricating fluid is introduced into a contact surface between the shoe and the piston through a through passage formed in the piston. 29. The lubricating fluid introduced into the contact surface between the shoe and the piston is introduced into the spherical contact surface between the shoe and the ring member through a through passage formed in the shoe. 28. The axial piston pump motor of 28. 30. The lubricating fluid introduced into the spherical contact surface between the shoe and the ring member is introduced into the sliding contact surface with the bearing ring member via the through passage formed in the ring member. 30. The axial piston pump / motor according to claim 29.