JP2505984Y2 - Swash plate type variable displacement piston machine - Google Patents

Description

[Detailed Description of the Invention] [Industrial application] The present invention relates to a swash plate type variable displacement piston machine in which the tilt angle of the swash plate is changed by an operation piston to change the reciprocating sliding amount of the piston. .

[Conventional technology]

Conventionally, a typical structure of this type of swash plate type variable displacement piston machine is to construct a pump body 3 as a machine body by closing one end opening of a body member 1 with a lid member 2 as shown in FIG. A cylinder block 5 which is rotated by a drive shaft 4 is rotatably accommodated in the pump body 3, and is slidably contacted with the cylinder block 5 and attached to a lid member 2 on a sliding contact surface of a valve plate 6. Intake port 8 communicating with the intake passage 7
And a discharge port 10 communicating with the discharge flow passage 9 are opened, and pistons are provided in a plurality of piston holes 5A penetrating the cylinder block 5.
A swash plate in which 11 is inserted and tiltably supported in the pump body 3
To the sliding plate 13 having 12
14 is provided in abutment to bias the swash plate 12 in the direction of increasing the tilt angle by the force of the spring 15 and resist the force of the spring 15 by the action force based on the pressure of the liquid introduced into the action chamber 16 formed at the back. The operation piston 17 is provided so as to abut the swash plate 12 so as to press the swash plate 12 in the direction of decreasing the tilt angle so as to be movable into the pump body 3, and the tilt angle of the swash plate 12 is maximized by the force of the spring 15. When the cylinder block 5 is rotated in the fourth illustrated state, each piston 11 causes a swash plate.
The maximum amount of discharge is obtained by sucking the liquid from the suction port 8 and discharging the liquid to the discharge port 10 by reciprocating in the axial direction with the maximum amount of reciprocating sliding along 12 to obtain the maximum discharge amount. When the tilt angle of the swash plate 12 is reduced by moving to, the reciprocating sliding amount of the piston 11 is changed so that the discharge amount to the discharge port 10 is decreased.

[Problems to be solved by the invention]

However, the swash plate 12 is hardened at the contact portion with the operation piston 17 so as to improve the wear resistance of the contact portion with the operation piston 17, and the swash plate 12 is distorted due to this quenching and the swash plate 12 is deformed. The sliding plate 13 provided in 12 and the shoe 14 provided at the tip of the piston 11 cause a trouble in the contact state, and good reciprocal sliding of the piston 11 cannot be obtained.
Before the quenching, the swash plate 12 that has been worked must be reworked so as to correct the distortion caused by the quenching, and there is a problem that the working becomes troublesome.

The present invention solves such a problem, and provides a swash plate type variable displacement piston machine in which the swash plate can be easily processed and a good reciprocal sliding of the piston can be obtained.

[Means for solving problems]

Therefore, according to the present invention, a cylinder block in which a plurality of piston holes are formed in the axial direction is rotatably accommodated in the machine body, and is inserted into each piston hole of the cylinder block to reciprocally slide in the axial direction. A swash plate is movably provided, and the tip of each piston protruding from the cylinder block is brought into contact with the piston to change the reciprocating sliding amount of the piston so that the swash plate can be tilted into the machine body. The operating piston is pushed to the swash plate so as to press the swash plate in the tilt angle decreasing direction by the action force based on the pressure of the liquid introduced into the working chamber formed in the back part against the spring force biasing in the tilt angle increasing direction. The swash plate is provided so as to be movable in the axial direction of the cylinder block inside the machine body by abutting it.The swash plate forms a cylindrical recess at the point of contact with the operating piston, and a hard spherical member is driven into the recess to fit into it. Fixed on the inner surface of the recess Is formed to be slightly smaller than the diameter of the spherical member, the radius of the spherical member is set to be smaller than the depth from the opening of the recess to the bottom surface, and the spherical member fixed to the swash plate is provided in contact with the operation piston. Become.

[Action]

In such a configuration, the swash plate pivotally supported in the machine body by freely changing the reciprocating sliding amount of the piston is
A hard spherical member is inserted into the contact point with the operating piston, and this spherical member is in contact with the operating piston.Therefore, quenching is performed at the contact point of the swash plate with the operating piston to improve wear resistance. Since it is possible to eliminate the need for re-working, it is possible to eliminate the need for reworking to correct the distortion that occurs in the swash plate due to this quenching, and it is possible to simplify the working and obtain good reciprocal sliding of the piston.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a case where it is applied to a swash plate type variable displacement piston pump, and 18 is a pump main body as a machine main body, in which a lid member 20 is fixed to a hollow main body member 19 having one end opened so as to close the opening. I am configuring. Reference numeral 21 denotes a drive shaft, which is rotatably supported by the pump body 18 and has one end protruding from the pump body 18. Reference numeral 22 is a cylinder block, which is integrally connected to the drive shaft 21 via a spline portion 23 and rotatably accommodated in the pump body 18. 24 is a plurality of piston holes formed in the cylinder block 22,
22 Along the same circumference around the axis, they are provided at equal intervals in the circumferential direction in the axis direction. A valve plate 25 is attached to the lid member 20 so as to be slidably contactable with one end surface of the cylinder block 22 where the piston hole 24 is opened. Reference numeral 26 is a liquid suction port, and 27 is a liquid discharge port. Each of the piston holes is formed by axially penetrating the valve plate 25 and opening at a sliding contact surface with which the cylinder block 22 slidably contacts. The piston holes 24 are arranged to face each other on the circumference having the same diameter as the circumference through which the piston holes 24 are provided so as to communicate alternately. 28 is a suction flow path, and 29 is a discharge flow path, which are provided on the lid member 20 and communicate with the suction port 26 and the discharge port 27, respectively. Reference numeral 30 denotes a piston, which is fitted and inserted into each piston hole 24 from the other end surface opposite to the one end surface which is in sliding contact with the valve plate 25 of the cylinder block 22, and is reciprocally slidable in the axial direction. Reference numeral 31 denotes a shoe, which is pivotably supported at the tip of each piston 30 protruding from the other end surface of the cylinder block 22 so as to be swingable. Reference numeral 32 denotes a swash plate, which is pivotally supported in the pump body 18 so as to freely change the reciprocating sliding amount of the piston 31, and the sliding plate 33 with which the shoe 31 at the tip of the piston 30 abuts has a disc shape. The main body 32A is attached to a recessed fitting hole 34, and protrudes from both ends of the main body 32A in the first vertical direction in the figure to form projecting portions 35A and 35B. 36A, 36B
Is a recess formed by denting one end surface of the swash plate 32 of the swash plate 32 into a cylindrical shape, and 37A is a steel ball for ball bearings (corresponding to JIS B 1501) as a hard spherical member. (Corresponding to JIS G 4805), the inner diameter of which is slightly smaller than the diameter of its own, and it is inserted into the recess 36A and fixed to the swash plate 32. It is provided so as to be in contact with the swash plate 32 so as to improve wear resistance without quenching the contact portion of the swash plate 32 with the operation piston 38. As shown in detail in FIGS. 2 and 3, the ball bearing steel ball 37A is provided with a radius R smaller than the depth H from the opening of the recess 36A to the bottom surface, and is driven into the recess 36A for fitting. After that, they are caulked at four points A, B, C and D. 37B is a ball-bearing steel ball similar to the ball-bearing steel ball 37A, and is provided by being driven into a recess 36B having the same shape as the recess 36A and then being caulked. Reference numeral 39 denotes a pressing piston, which is movably fitted in a guide member 40 projecting from the lid member 20 into the pump main body 18 in the axial direction of the cylinder block, and is attached to a ball bearing steel ball 37B having a swash plate 32 at its tip. It is provided in abutment.
For this reason, the swash plate 32 does not need to be hardened at the contact portion with the operation piston 38 as well as the contact portion with the pressing piston 39. 41 is a spring, which is a pressing piston 39 and a guide member.
It is provided so as to be sandwiched between 40 and to bias the swash plate 32 in the tilt angle increasing direction via the pressing piston 39. 42 is a pressing piston
39 In the working chamber formed on the back, discharge channel 29 via channel 43
The operation force based on the pressure of the liquid introduced from the discharge flow path 29 is applied to the pressing piston 39 to urge the swash plate 32 in the tilt angle increasing direction. The operation piston 38 that is in contact with the ball-bearing steel ball 37A of the swash plate 32 is
A guide member 44 protruding from the inside of the pump main body 18 is provided so as to be movable in the axial direction of the cylinder block.
Reference numeral 45 denotes a working chamber formed at the back of the operating piston 38, in which the working cross-sectional area for the working piston 38 is set larger than the working cross-sectional area for the pressing piston 39 in the working chamber 42, and the working force based on the pressure of the introduced liquid is the working piston. 38 is given to 38 springs to swash plate 41
The force is applied in the direction of decreasing the tilt angle against the force and the action force based on the pressure of the liquid introduced into the action chamber 42. 46 is a primary side flow path branched from the discharge flow path 29 and opened to the outer surface of the lid member 20, and 47 is a secondary side flow path that is connected to a working chamber 45 formed at the back of the operation piston 38 and opened to the outer surface of the lid member 20. A flow passage, 48 is a discharge flow passage that is connected to the low pressure side via the inside of the pump body 18 and opens to the outer surface of the lid member 20, 49 is a pressure control valve, and the respective flow passages 46, 4
7 and 48 are attached to the outer surface of the lid member 20 having an opening, and have
A flow path 50 connected to the primary side flow path 46, a flow path 51 connected to the secondary side flow path 47, and a flow path 52 connected to the discharge flow path 48 are provided with an opening in the valve hole 53. There is. Reference numeral 54 denotes a valve body of the pressure control valve 49, which is slidably fitted in the valve hole 53. Then, the valve body 54 is a discharge flow path 29 acting on one end through the flow path 50.
When the pressure is less than or equal to the set pressure based on the force of the spring 55 acting on the other end, the flow passage 51 is located in the first illustrated state, communicates with the flow passage 52 to block the flow passage 50, and the discharge flow passage 29 Pressure is spring
When the set pressure based on the force 55 is exceeded, it slides to the left in the first figure to switch the flow path 51 to the flow path 50 so as to communicate with the flow path 52 and to cut off from the flow path 52. Therefore, the operating piston 38 is
Is less than the set pressure, the tilt angle of the swash plate 32 is maximum at the retracted position in the first illustrated state, and the liquid introduced into the working chamber 45 when the pressure in the discharge flow path 29 exceeds the set pressure. The swash plate 32 moves to the left in the first figure by the action force based on the pressure of
Decrease the tilt angle of. Reference numeral 56 denotes an adjusting bolt for adjusting the maximum tilt angle of the swash plate 32, which is provided so as to come into contact with the back portion of the operating piston 38 and to move back and forth in the axial direction of the cylinder block. Reference numeral 57 denotes a control valve, which is a flow path 58 that connects the primary side flow path 46 and the pump main body 18 to each other.
Is arranged in order to introduce a part of the liquid discharged into the discharge passage 29 into the pump main body 18 at the initial stage of pump operation due to the rotation of the cylinder block 22.

 Next, the operation of this configuration will be described.

FIG. 1 shows a state where the pump operation is stopped, and the swash plate 32 is a spring 41.
The force is urged through the pressure piston 39 to maximize the tilt angle, the operating piston 38 is in the retracted position, and the pressure control valve
In 49, the valve body 54 is in the position shown in the figure by the force of the spring 55, and the flow passage 51 is connected to the flow passage 52 to cut off the flow passage 50. Drive shaft
When cylinder block 22 is rotated by 21, each piston
30 is reciprocally operated in the axial direction with the maximum amount of reciprocal sliding along the swash plate 32 having the maximum tilt angle, and the liquid suction passage 28,
The maximum discharge amount is obtained by sucking through the suction port 26 and discharging into the discharge port 27 and the discharge flow path 29. Then, when the pressure of the discharge flow passage 29 exceeds the set pressure of the pressure control valve 49, the valve body 54 slides in the left direction in the drawing to switch the flow passage 51 to the flow passage 50 to communicate with the flow passage 52.
And a part of the liquid in the discharge flow channel 29 flows through the primary flow channel 46, the flow channels 50, 51, and the secondary flow channel 47 and is introduced into the working chamber 45.
The operation piston 38 moves to the left in the drawing by an action force based on the pressure of the liquid introduced into the action chamber 45, and moves the swash plate 32 to the spring 41 force applied through the pressing piston 39 and the liquid introduced into the action chamber 42. Pressing against the action force based on the pressure to reduce the tilt angle, the reciprocating sliding amount of each piston 30 decreases and the discharge flow path
Discharge rate to 29 decreases. Discharge passage due to decrease in discharge amount
When the pressure of 29 falls below the set pressure of the pressure control valve 49, the valve body
The liquid 54 in the working chamber 45 flows out through the secondary-side flow passage 47, the flow passages 51 and 52, and the discharge flow passage 48 and is led out.
Is pushed by the force of the spring 41 and the acting force based on the pressure of the liquid introduced into the working chamber 42 to maximize the tilt angle, the operating piston 38 returns to the state shown in the figure, and the maximum discharge amount is obtained again. In this way, the set pressure of the pressure control valve 49 of the discharge passage 29 is controlled. Then, when the rotation of the cylinder block 22 is stopped, the suction and discharge of the liquid are stopped and the pump operation is stopped.

With such an operation, the swash plate 32 that allows the reciprocating sliding amount of the piston 30 to be freely changed is driven into the ball bearing steel ball 37A by inserting the ball bearing steel ball 37A into the contact position with the operation piston 38, and the ball bearing steel ball 37A is inserted. Since the swash plate 32 is in contact with the operation piston 38, it is not necessary to quench the contact portion of the swash plate 32 with the operation piston 38 to improve wear resistance. Therefore, the distortion caused in the swash plate 32 is corrected by this quenching. Therefore, it is possible to eliminate the need for reworking, simplify the working, and obtain good reciprocal sliding of the piston 30. Further, the diameter of the inner circumference is slightly smaller than the diameter of the ball-bearing steel ball 37A, and the radius R of the ball-bearing steel ball 37A is set to be smaller than the depth H from the opening to the bottom. Since the ball bearing steel ball 37A is inserted into the concave portion 36A of the shape and fixed to the swash plate 32, a screw member is formed to project on the ball bearing steel ball and this screw member is formed on the swash plate. Even if the steel balls for ball bearings are fixed to the swash plate by screwing them into the screw holes, it is possible to eliminate the need for quenching at the contact point of the swash plate with the operating piston. The steel ball 37A for ball bearings can be easily fixed to the swash plate 32 without requiring any fixing means, and the swash plate 32 can be vibrated due to vibrations caused by pump operation.
The steel ball 37A for ball bearings fixed to can be firmly fixed without loosening. Further, the ball bearing steel ball 37A can be used as it is as a general-purpose one, and it is not necessary to manufacture it specially for use in the swash plate type variable displacement piston pump, and it can be manufactured at low cost.

In one embodiment, the ball-bearing steel ball 37A is driven into the recess 36A and fitted into the recess 36A, but the caulking may be omitted. Although the swash plate type variable displacement piston pump is used, it goes without saying that a swash plate type variable displacement piston motor may be used.

[Effect of device]

As described above, according to the present invention, a cylinder block having a plurality of piston holes formed in the axial direction is rotatably housed in the machine body, and is fitted into each piston hole of the cylinder block to reciprocate in the axial direction. A slidable piston is provided, the tip of each piston protruding from the cylinder block is abutted, and the reciprocating sliding amount of the piston can be changed and freely manipulated to tiltably support the swash plate into the machine body. The operating piston to push the swash plate in the tilt angle decreasing direction by the action force based on the pressure of the liquid introduced into the working chamber formed in the back part against the spring force that biases the swash plate in the tilt angle increasing direction. Is provided so as to be movable in the axial direction of the cylinder block inside the machine body, and the swash plate forms a cylindrical recess at the point of contact with the operation piston.
A hard spherical member is driven into the recess and fixed to the swash plate to form the inner diameter of the recess slightly smaller than the diameter of the spherical member, and the radius of the spherical member from the opening to the bottom of the recess. Since the spherical member fixed to the swash plate is provided in contact with the operation piston, the contact point of the swash plate with the operation piston does not require hardening to improve wear resistance. Therefore, it is possible to eliminate the need for reworking to correct the strain generated in the swash plate by this quenching, simplify the working, and obtain good reciprocal sliding of the piston.

In addition, the diameter of the inner circumference is formed to be slightly smaller than the diameter of the hard spherical member, and the spherical member is driven into a cylindrical concave portion in which the radius of the spherical member is set to a small dimension from the depth from the opening to the bottom surface. Even if the spherical member is fixed to the swash plate by screwing it into the screw hole formed on the swash plate by protrudingly forming the screw member on the spherical member, Although it is possible to prevent the plate from contacting the operation piston with quenching, compared to this, special fixing means such as a screw member is not required and the spherical member can be easily fixed to the swash plate. At the same time, the spherical member fixed to the swash plate can be firmly fixed without loosening due to vibration caused by mechanical operation or the like. Further, since the spherical member can be used as it is, it can be manufactured at low cost because it does not have to be manufactured specially for use in a swash plate type variable displacement piston machine.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a swash plate type variable displacement piston pump as a swash plate type variable displacement piston machine showing an embodiment of the present invention, and FIG. 2 is an enlarged view of a main portion II of FIG. FIG. 3 is a view seen from an arrow III in FIG. 2, and FIG. 4 is a vertical cross-sectional view of a conventional swash plate type variable displacement piston pump. 18 …… Pump body (machine body), 22 …… Cylinder block, 24 …… Piston hole, 30 …… Piston, 32 …… Swash plate,
36A: recess, 37A: steel ball for ball bearing (spherical member) 38:
Operating piston, 41 ... Spring, 45 ... Working chamber.

Claims (1)

(57) [Scope of utility model registration request] 1. A cylinder block in which a plurality of piston holes are formed in the axial direction is rotatably accommodated in a machine body, and is reciprocally slidable in the axial direction by being inserted into each piston hole of the cylinder block. A piston is attached to the cylinder block, abutting on the tip of each piston protruding from the cylinder block, the reciprocating sliding amount of the piston can be changed, and the swash plate is tiltably supported in the machine body. The operating piston is brought into contact with the swash plate so as to press the swash plate in the tilt angle decreasing direction by the action force based on the pressure of the liquid introduced into the working chamber formed in the back part against the spring force biasing in the angle increasing direction. It is installed in the machine body so that it can move in the axial direction of the cylinder block.The swash plate forms a cylindrical recess at the point of contact with the operating piston, and a hard spherical member is driven into the recess and fixed to the swash plate. The inner diameter of the recess is spherical. The diameter of the material is slightly smaller than the diameter of the material, the radius of the spherical member is smaller than the depth from the opening of the recess to the bottom surface, and the spherical member fixed to the swash plate is provided in contact with the operation piston. Plate type variable displacement piston machine.