JP2000018151A - Axial plunger type hydraulic equipment - Google Patents

Abstract

(57) Abstract: A plunger (31) is inserted into a cylinder bore (30) formed in a cylinder block (3) in a casing (1), and a valve plate (5) is interposed between the cylinder block (3) and an end piece (12) of the casing (1). In an axial plunger type hydraulic device in which oil flows between oil passages 120 and 121 formed in the end piece 12 and the cylinder bore 30 through ports 50 and 51 formed in the valve plate 5, the end piece 12 has a hydraulic resistance. Even if deformed by force, the sealing property between the valve plate 5 and the cylinder block 3 is ensured. A portion of a surface (5b) of a valve plate (5) on the side of an end piece (12) outside the outer diameter of a port land (5b-1) is formed in a groove (5b-4). When the end piece 12 is deformed, the valve plate 5 is deformed so as to follow the end piece 12 with the outer peripheral edge of the port land portion 5b-1 as a starting point. Since the outer diameter of the valve plate 5 is smaller than that of the valve plate 5, the amount of deformation of the valve plate 5 is reduced, the gap between the valve plate 5 and the cylinder block 3 is reduced, and oil leakage is effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial plunger type hydraulic device used as a hydraulic pump or a hydraulic motor.

[0002]

2. Description of the Related Art Conventionally, an axial plunger type hydraulic device includes a cylinder block connected to a rotating shaft supported in a casing, and a plunger reciprocally fitted into a plurality of cylinder bores formed in the cylinder block. ,
A swash plate that regulates the reciprocation of the plunger, which is disposed at one end in the axial direction within the casing, and an annular valve plate that comes into sliding contact with the end face of the cylinder block and is attached to the end piece at the other end in the axial direction of the casing. The hydraulic fluid is configured to flow through an arc-shaped port formed in a valve plate between an oil passage formed in an end piece and a cylinder bore (JP-B-51-14282, JP-B-51-14282). Kosho 51
-14283).

Conventionally, a port land for opening the port and a groove outside the outer diameter of the port land are formed on a surface of the valve plate facing the cylinder block and a surface of the valve plate facing the end piece, respectively. And an outer peripheral land portion outside the outer diameter of the groove portion.

[0004]

When the hydraulic pressure in the cylinder bore becomes high, the end piece is deformed so as to protrude outward in the axial direction due to the hydraulic reaction force, and the valve plate follows the axial direction. It deforms outwardly, creating a gap between the port land and the cylinder block on the surface facing the cylinder block of the valve plate, and high-pressure oil leaks from this gap,
The efficiency drops significantly.

In this case, it is conceivable to increase the rigidity of the end piece to prevent its deformation. However, in this case, the end piece becomes heavy, which causes a problem that the weight of the hydraulic equipment increases.

SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide an axial plunger type hydraulic device capable of preventing high pressure oil leakage without increasing rigidity of an end piece.

[0007]

Means for Solving the Problems In order to solve the above problems,
According to the present invention, a cylinder block connected to a rotating shaft pivotally supported in a casing, a plunger inserted in a plurality of cylinder bores formed in the cylinder block so as to be reciprocally movable, and disposed on one axial end side in the casing. A swash plate that regulates the reciprocation of the plunger, and an annular valve plate that slides on the end face of the cylinder block and is attached to the end piece at the other end in the axial direction of the casing. In the hydraulic fluid flowing through an arc-shaped port formed in the valve plate between the passage and the cylinder bore, formed on the surface of the valve plate facing the end piece,
The portion of the facing surface outside the outer diameter of the port land portion for opening the port is formed in a groove portion lower than the port land portion over the entire area.

When the end piece is deformed so as to protrude outward in the axial direction, and the valve plate is deformed following the deformation, the amount of deformation of each portion of the valve plate outward in the axial direction is determined by the amount of deformation of the valve plate relative to the end piece. The larger the distance from the outer peripheral edge of the contact surface as a starting point to the radially inward thereof, the larger the contact surface becomes. Here, according to the present invention, the outer peripheral edge of the contact surface with the end piece is the outer peripheral edge of the port land portion having a diameter obtained by adding a predetermined seal width to the outer diameter of the port. Then, even if the end piece is deformed, the portion near the outer periphery of the port land portion surely comes into pressure contact with the end piece,
Even if the seal width is small, the sealing property against high-pressure oil can be ensured, so that the outer diameter of the port land can be considerably smaller than the outer diameter of the valve plate. Thus, the radial distance between the contact starting position of the valve plate with respect to the end piece and the inner peripheral edge of the port land becomes shorter, and the axial deformation of the valve plate at this inner peripheral edge also becomes smaller. As a result, generation of a gap due to deformation of the valve plate between the port land and the cylinder block on the surface facing the cylinder block of the valve plate is suppressed, and leakage of high-pressure oil is effectively prevented.

If the valve plate is made of a material having a Young's modulus smaller than that of the cylinder block and the end piece, the port lands on each surface of the valve plate are compressed so as to follow the cylinder block and the end piece. The gap between the land for use, the cylinder block, and the end plate is further narrowed, and leakage of high-pressure oil is more effectively prevented.

Incidentally, a tilting moment acts on the cylinder block due to the component force of the reaction force from the swash plate acting on the plunger. A groove is formed outside the outer diameter of the port opening on the surface of the valve plate facing the cylinder block, and an outer circumferential land portion is formed outside the outer diameter of the groove to suppress the inclination of the cylinder block with respect to the valve plate. When formed, the end piece is deformed so as to be convex outward in the axial direction, and the valve plate is deformed in the axial direction following this,
When the pressing force on the cylinder block side in the radially outer portion of the valve plate increases, the pressing force concentrates on the outer peripheral land on the surface of the valve plate facing the cylinder block. Metal contact with the metal, which may lead to friction and seizure.
In this case, if the outer diameter of the port land portion on the surface opposing the end piece of the valve plate is equal to or less than the inner diameter of the outer peripheral land portion on the surface opposing the cylinder block of the valve plate, the valve plate that follows the deformation of the end piece is formed. The pressing force applied to the outer peripheral land portion due to the deformation can be reduced, and the metal contact between the valve plate and the cylinder block in the outer peripheral land can be prevented, so that the durability can be improved, which is advantageous.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes a casing comprising a cylindrical main body 10 and end pieces 11, 12 bolted to one end and the other end in the axial direction of the cylindrical main body 10, respectively. In the casing 1, there are end pieces 11, 12
The rotating shaft 2 is supported by bearings 13 and 14 mounted on the cylinder block 3 by spline coupling with the rotating shaft 2.
Are linked.

The cylinder block 3 has a plurality of cylinder bores 30 that are open at one end in the axial direction at intervals in the circumferential direction.
Are formed, and each cylinder bore 30 has a plunger 3
1 is reciprocally fitted so that the oil chamber 32 in the cylinder bore 30 defined by the plunger 31 is expanded and contracted by the reciprocating movement of the plunger 31. Plunger 3
1 is connected to one end of the shoe 31 via a spherical joint 31a.
b is connected, and a swash plate 4 for bringing the shoe 31b into contact with one end of the casing 1 in the axial direction is arranged so that the tilt angle with respect to the rotating shaft 2 can be changed by a tilt mechanism (not shown). On the right side of FIG. 1, the plunger 31 is moved back to the other end in the axial direction to contract the oil chamber 32, and on the left side in FIG.
2 is expanded.

An annular valve plate 5 slidably in contact with the end surface of the other end in the axial direction of the cylinder block 3 is provided on the other end side in the axial direction of the casing 1 with respect to the end piece 12 at the other end in the axial direction of the casing 1. It is arranged in a stopped state. The oil chamber 3 of the cylinder bore 30 existing on the right side of FIG.
2 and 3 through a communication hole 33 formed in the end face of the cylinder block 3.
0 and the oil chamber 32 of the cylinder bore 30 on the left side of FIG.
Similarly, an arcuate low-pressure port 51 communicating with the high-pressure port 50 is formed in the end piece 12, and a low-pressure port 51 is formed in the end piece 12. And a low-pressure oil passage 121 communicating with the low-pressure oil passage 121. In the figure, reference numeral 52 denotes a knock hole for preventing the valve plate 5 from rotating around the end piece 12.

In the axial plunger type hydraulic device configured as described above, when the rotary shaft 2 is driven to rotate, oil is sucked into the oil chamber 32 of the cylinder bore 30 from the low pressure oil passage 121 through the low pressure port 51 on the left side in FIG. 1, high-pressure oil is discharged from the oil chamber 32 to the high-pressure oil passage 120 via the high-pressure port 50 to function as a hydraulic pump, and supplies high-pressure oil to the high-pressure oil passage 120 from another hydraulic pump. Then
1, the plunger 31 is pushed in the forward movement direction, and the rotary shaft 2 is rotationally driven via the cylinder block 3 by the reaction force from the swash plate 4, and functions as a hydraulic motor.

The cylinder block 3 is pressed to the other end in the axial direction by a spring 34 and the oil pressure in the oil chamber 32. With this pressing force, the sealing property between the cylinder block 3 and the valve plate 5 is improved. The sealing property between the valve plate 5 and the end piece 12 is ensured.

As shown in FIG. 2, an annular port land 5a for opening the high-pressure port 50 and the low-pressure port 51 is formed on the surface 5a of the valve plate 5 facing the cylinder block 3.
1, an annular groove portion 5a-2 outside the outer diameter of the port land portion 5a-1, and an annular outer peripheral land portion 5a-3 outside the outer diameter of the groove portion 5a-2. The inner side of the inner diameter of the land 5a-1 is a groove 5a-4 reaching the inner peripheral edge of the valve plate 5. Also, as shown in FIG. 3, on the surface 5b of the valve plate 5 facing the end piece 12,
An annular port land 5b-1 for opening the high-pressure port 50 and the low-pressure port 51, and a port land 5b-
1 and an annular groove 5b-2 inside the inner diameter of
An inner circumferential land portion 5b-3 inside the inner diameter of No. 2 is formed. The outer diameter of the port land portion 5b-1 has a dimension obtained by adding a predetermined seal width to the outer diameter of the high-pressure port 50 and the low-pressure port 51, and the port land portion 5b-1.
The portion outside the outer diameter of the port land portion 5 covers the entire area.
It is formed in a groove 5b-4 lower than b-1. The outer diameter of the port land portion 5a-1 on the surface 5a of the valve plate 5 is
b is larger than the outer diameter of the port land portion 5b-1.
The outer diameter of b-1 is smaller than the inner diameter of the outer peripheral land portion 5a-3 of the surface 5a. The outer peripheral land portion 5a-3 of the surface 5a of the valve plate 5 is circumferentially divided by a radial groove portion 5a-5 extending radially outward from the groove portion 5a-2.
The port land 5b-1 and the inner peripheral land 5b-3 of the surface 5b are also circumferentially divided by radial grooves 5b-5 and 5b-6 extending radially outward and inward from the groove 5b-2. Have been. Further, the valve plate 5 has inner grooves 5a-4 and 5b-2 on both surfaces 5a and 5b and outer grooves 5a-5b.
A lubricating hole 53 that communicates with the 2,5b-4 is also formed.

When the oil pressure in the oil chamber 32 of the cylinder bore 30 becomes high, the end piece 12 is deformed so as to protrude outward in the axial direction, and the valve plate 5 is accordingly moved outward in the axial direction. Thus, a gap is formed between the port land portion 5 a-1 on the surface 5 a of the valve plate 5 and the cylinder block 3. Here, since the amount of deformation of the end piece 12 is extremely small compared to the diameter of the valve plate 5, the amount of deformation of each part of the valve plate 5 in the axially outward direction, that is, the amount of clearance between the end plate 12 and the cylinder block 3 is: It can be imitated that it increases in proportion to the radial distance from the outer peripheral edge of the contact surface of the valve plate 5 to the end piece 12. Port land portion 5b-1 on surface 5b of valve plate 5
Is extended over the outer peripheral edge of the valve plate 5, or when the groove and the outer peripheral land outside the port land 5b-1 are formed. The clearance amount δ ′ between the inner peripheral edge of the port land portion 5a-1 on the surface 5a and the cylinder block 3 is represented by D ′, the difference between the outer diameter of the valve plate 5 and the inner diameter of the port land portion 5a-1. Assuming that K is a proportional constant, δ ′ = K · D ′. On the other hand, according to the present embodiment, the end piece 12
The outer peripheral edge of the contact surface of the valve plate 5 with respect to the
Between the outer diameter of the port land 5b-1 and the cylinder block 3 at the inner periphery of the port land 5a-1 on the surface 5a of the valve plate 5 having a diameter obtained by adding a predetermined seal width to the outer diameter of the port block 5b-1. Is the difference between the outer diameter of the port land 5b-1 and the inner diameter of the port land 5a-1, and δ = KD = δ'D / D '. Here, even if the end piece 12 is deformed, the portion near the outer periphery of the port land portion 5b-1 surely comes into pressure contact with the end piece 12, so that even if the seal width is considerably reduced, leakage of high-pressure oil can be prevented. Thus, the port land portion 5b-
1 can be made considerably smaller than the outer diameter of the valve plate 5 to make D less than or equal to 1/2 of D '. Since the amount of oil leak is proportional to the cube of the amount of gap, according to the present embodiment, the amount of leak is increased by extending the port land portion 5b-1 over the outer peripheral edge of the valve plate 5. And the leakage of high-pressure oil is effectively prevented.

In this embodiment, the valve plate 5 is formed of a material having a smaller Young's modulus than the cylinder block 3 and the end piece 12. For example, cylinder block 3
The end piece 12 is formed of an iron-based material, and the valve plate 5 is formed of a copper-based material. According to this, the surface 5b of the valve plate 5
The port land 5b-1 is compressed according to the deformation of the end piece 12, so that the flatness of the surface 5a of the valve plate 5 is easily ensured, and further, the port land 5a- of the surface 5a.
1 is also compressed following the cylinder block 3, and between the valve plate 5 and the cylinder block 3 and between the valve plate 5 and the end piece 1.
2 is further improved. In order to reduce the weight of the end piece 5, the end piece 5 is desirably formed of a material having a smaller Young's modulus than the cylinder block 3.

A tilting moment acts on the cylinder block 3 due to a radial component of the rotating shaft 2 of a reaction force from the swash plate 4 acting on the plunger 31. And the valve plate 5
When the portion of the surface 5b outside the outer diameter of the port land portion 5b-1 is formed in the groove portion 5b-4 as described above, the cylinder block 3 acting on the outer peripheral land portion 5a-3 of the surface 5a of the valve plate 5 Is not present on the surface 5b of the valve plate 5, the valve plate 5 tilts around the outer peripheral edge of the port land 5b-1, and the cylinder lock 3 is easily tilted. However, in the present embodiment, the outer diameter of the port land portion 5a-1 on the surface 5a of the valve plate 5 is changed to the surface 5b of the valve plate 5 as described above.
Because the outer diameter of the port land 5b-1 is larger than that of the port land 5b-1,
The pressure receiving area by the oil film formed by the oil that enters between the contact surfaces with the oil increases. As a result, the pressing force acting on the outer peripheral port portion 5a-3 decreases, and the distribution of the pressing force acting on the surface 5a of the valve plate 5 changes to the port land portion 5b- on the surface 5b of the valve plate 5.
1, the distribution becomes easy to receive the pressing force, and the inclination of the cylinder block 3 is effectively prevented.

Here, the pressing force of the cylinder block 3 against the valve plate 5 when high oil pressure is generated in the oil chamber 32 is represented by F, and the pressure receiving reaction force due to the oil film on the port land portion 5a-1 on the surface 5a of the valve plate 5. As HF, the ratio of HF to F (HF /
When F) is larger than 0.95, the cylinder block 3
Is more likely to leak from the valve plate 5 and the hydraulic pressure leaks easily, and if it is smaller than 0.85, the cylinder block 3 is strongly pressed against the valve plate 5 and the frictional resistance becomes too large. Therefore, it is necessary to design the area of the port land portion 5a-1 so that HF = F × (0.85 to 0.95). The outer peripheral land portion 5a-3 which functions to suppress the inclination of the cylinder block 3 in response to the aforementioned tilting moment is F × (0.0
5 to 0.15). Under such conditions, the pressing force acting on the outer peripheral land portion 5a-3 is reduced as much as possible.
The area of a-1 is set so that HF is closer to F × 0.95, and the pressing force acting on the outer peripheral land portion 5a-3 is closer to F × 0.05. Since the port land 5b-1 on the surface 5b of the valve plate 5 does not rotate relative to the end piece 12, only the hydraulic pressure leakage needs to be considered. Therefore, the pressure receiving by the oil film on the port land 5b-1 is sufficient. The reaction force may be smaller than F × 0.85. Thus, the outer diameter of the port land portion 5b-1 on the surface 5b is made relatively small, and the port land portion 5a-
By making the outer diameter of the cylinder block 3 larger than the outer diameter of the port land portion 5b-1 on the surface 5b, it is possible to effectively prevent the hydraulic block from leaking and increase the frictional resistance while also effectively preventing the cylinder block 3 from tilting.

Further, due to the deformation of the valve plate 5 following the deformation of the end piece 12, the pressure receiving reaction force HF at the port land portion 5a-1 decreases, and the outer peripheral land portion 5a-3 is connected to the valve plate 5 side. When the pressing force applied from is concentrated, the outer peripheral land portion 5a
At -3, metal contact between the valve plate 5 and the cylinder block 3 occurs, which may result in abrasion, seizure and the like. However, in the present embodiment, the outer diameter of the port land portion 5b-1 on the surface 5b of the valve plate 5 is set to be equal to or less than the inner diameter of the outer peripheral land portion 5a-3, and the portion of the surface 5b that matches the outer peripheral land portion 5a-3 is formed. Since it is floating from the end piece 12, the pressing force applied to the outer peripheral land portion 5a-3 is reduced, and metal contact between the valve plate 5 and the cylinder block 3 at the outer peripheral land portion 5a-3 is effectively prevented.

[0022]

As is apparent from the above description, according to the present invention, high pressure oil leakage can be effectively prevented by a simple modification of the valve plate without increasing the rigidity of the end piece, and the efficiency can be improved. Good and cheap hydraulic equipment can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an example of a hydraulic device according to the present invention.

FIG. 2 is a side view of the valve plate viewed from the cylinder block side.

FIG. 3 is a side view of the valve plate seen from the end piece side.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Casing 12 End piece 120, 121 Oil passage 2 Rotating shaft 3 Cylinder block 30 Cylinder bore 31 Plunger 4 Swash plate 5 Valve plate 5a Opposed surface of valve plate to cylinder block 5a-1 Port land 5a-2 Groove 5a-3 Outer periphery Land portion 5b Opposing surface of valve plate facing end piece 5b-1 Port land portion 5b-4 Groove portion 50, 51 port

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yasuhiro Morimoto 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3H070 AA01 BB04 CC29 DD09 DD69 DD91 3H084 AA08 AA16 AA45 BB07 CC40

Claims (3)

[Claims] 1. A cylinder block connected to a rotating shaft pivotally supported in a casing, a plunger reciprocally fitted in a plurality of cylinder bores formed in the cylinder block, and one axial end in the casing. A swash plate that regulates the reciprocation of the plunger, and an annular valve plate that is attached to the end piece at the other end in the axial direction of the casing and that slides on the end face of the cylinder block. The hydraulic oil is circulated through an arc-shaped port formed in the valve plate between the valve plate and the outer surface of the port land portion formed on the surface facing the end piece of the valve plate and opening the port. The axial plunger type hydraulic device, wherein the opposed surface portion is formed in a groove portion lower than the port land portion over the entire area. 2. The axial plunger-type hydraulic device according to claim 1, wherein a port land for opening the port is provided on a surface of the valve plate facing the cylinder block, and the port land is outside the outer diameter of the port land. And an outer circumferential land portion outside the outer diameter of the groove portion, wherein the outer diameter of the port land portion on the surface facing the end piece of the valve plate is the outer circumferential land on the surface facing the cylinder block of the valve plate. Axial plunger-type hydraulic equipment, characterized in that the inner diameter is equal to or less than the inner diameter of the part. 3. The axial plunger type hydraulic device according to claim 1, wherein the valve plate is formed of a material having a smaller Young's modulus than the cylinder block and the end piece.