JPH02252978A - Axial piston motor - Google Patents

Abstract

PURPOSE:To reduce the power loss by forming a hole part for discharging the low pressure fluid outside a case, onto a sliding surface between a cylinder block and the case and introducing the high pressure liquid which leaks between the cylinder block and the case into the hole part. CONSTITUTION:When high pressure oil is sent into a high pressure side port 30 of an axial piston motor 10 on the upstream side from a reservoir tank 55 by an oil pump 1, a plunger 13 is pushed towards a swash plate 14 by the oil pressure, and a shoe 50 tends to move along the tilt of the swash plate 14. Therefore, a revolution torque is generated on a cylinder block 12, which performs revolution movement. At this time, a relatively large quantity of pressurized liquid leaks from the part between a plunger port 12b and a communication hole 30a between the cylinder block 12 and a valve plate 11, and in this case, the leak liquid flows out to a low pressure side port 31 from a communication hole 31a through the large and small ring-shaped balance grooves 12a having different diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an axial piston motor.

[Conventional technology]

Conventionally, as a hydraulic motor for high pressure, an axial piston motor as described in Hydraulic Equipment Design published by Kindai Kogaku Shuppan (edited by Takeo Tanaka), page 132, or as shown in FIG. 6, is known. In this conventional axial piston motor, the pressure fluid leaking from between the cylinder block 200 and the valve plate 202 is removed from the cylinder block 200.
Since the balance groove 204 provided in a ring shape on the end face of 00 communicates with the case chamber 206, the water flows out into the case chamber 206. This leaked pressure liquid was returned from the drain boat 208 to the reservoir tank 210 in order to maintain the case chamber 206 at drain pressure.

Note that 212 is a high-pressure side boat, and 214 is a low-pressure side boat.

[Problem to be solved by the invention]

However, since the pressure fluid that flows out is at high pressure, power loss occurs.Especially in a system where multiple axial piston motors are connected in series, each high pressure side port of the upstream axial piston motor is There was a problem in that the sum of the operating differential pressures of the axial piston motors was added, and the leakage of pressure fluid also increased.

The present invention has been made in view of the above-mentioned problems, and when back pressure acts on the low-pressure side boat of the upstream motor, such as when at least two axial piston motors are connected in series, the outflow of pressurized fluid. The object of the present invention is to provide an axial piston motor that can reduce power loss due to

[Means to solve the problem]

In order to achieve the above object, in the invention according to claim 1, in an axial piston motor that rotates a shaft by driving a cylinder block by the pressure of a liquid, a case that pivotally supports the shaft and surrounds the cylinder block is provided. a first hole provided in the case for supplying high-pressure liquid to the cylinder block from the outside of the case; and a first hole provided in the case for discharging low-pressure liquid from the cylinder block to the outside of the case. , a second hole provided in the case; and a second hole provided on a sliding surface between the cylinder block and the case that is in contact with the first and second holes, and communicating only with the second hole. The structure includes a ring-shaped groove portion.

Further, in the invention according to claim 2, in the axial piston motor that drives a cylinder block using liquid pressure to rotate a shaft, the axial piston motor includes: a case that pivotally supports the shaft and surrounds the cylinder block; and an exterior of the case. a first hole provided in the case for supplying high-pressure liquid from the cylinder block to the outside of the case; and a first hole provided in the case for discharging low-pressure liquid from the cylinder block to the outside of the case. a ring-shaped groove provided on a sliding surface of the cylinder block and the case in contact with the first and second holes and communicating only with the second hole; , a predetermined space provided between the shaft and the cylinder block, and a communication hole that communicates the space with the first or second hole.

[Operation] When high-pressure liquid is supplied from the outside of the axial piston motor configured as above to the cylinder block through the first hole provided in the case, the cylinder block rotates due to the liquid pressure. Initially, the shaft rotates together with the cylinder block.

Thereafter, the high-pressure liquid becomes a low-pressure liquid, passes through a second hole provided in the case, is discharged to the outside of the axial piston motor, and is discharged to the outside of the axial piston motor connected downstream in series. It is sent out to hole 1. The liquid leaking from the sliding surface between the cylinder block and the case is discharged to the outside of the axial piston motor through the ring-shaped groove and the second hole, and is then discharged to the outside of the axial piston motor connected downstream in series. is delivered to the first hole.

〔Example〕

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

FIG. 1 is a diagram showing a first embodiment of the present invention, in which an oil pump 1 sucks oil from a reservoir tank 55 through a suction pipe 51, and pumps high-pressure oil through a pipe line 52 to an axial pump on the upstream side. It is force-fed to the high-pressure side port 30 of the piston motor 10. The low-pressure port 31 of the upstream axial piston motor 10 is communicated with a high-pressure port (not shown) of the downstream axial piston motor 20 via a conduit 53.

A low-pressure port (not shown) of the downstream axial piston motor 20 is communicated with a reservoir tank 55 via a conduit 54 . Although there is only one reservoir tank 55, a plurality of reservoir tanks 55 are shown for convenience in the drawings. The upstream axial piston motor 10 has a drain port 32.
is provided and communicates with the reservoir tank 55. Similarly, for the downstream axial piston motor 20,
A drain port 20a (not shown) is provided.

Next, the detailed structure of the upstream axial piston motor 10 will be explained. In FIG. 1, the shaft 15 is rotatably fitted into a bearing 47 and a bearing 40 provided on a cover 56, and a C-shaped circlip 48 prevents the bearing 47 and the shaft 15 from separating from the housing 57. It is elastically crimped to the housing 57 as shown in FIG. The circlip 49 is elastically crimped onto the shaft 15 in order to fix the bearing 47 to the shaft 15. The shaft 15 is provided with a gear-shaped spline portion 15b in order to transmit the rotational force of the cylinder block 12 to the shaft 15, and is fitted with the spline portion of the cylinder block 12 and the spline portion of the stopper 45. . A keyway 15a is provided at the tip of the shaft. shaft 15
, cylinder block 12, and stopper 45 coaxially rotate integrally. The ring-shaped oil seal 16 is pressed into the recess of the housing 57 to grip the shaft 15 and keep the case chamber 17 partitioned by the housing 57 and the cover 56 liquid-tight. The cover 56 is provided with a high pressure side port 3o for introducing high pressure oil and a low pressure side port 31 for discharging low pressure oil. The convex portion 56a on the surface of the cover 56 facing the housing 57 is located on the valve plate 11 (the fourth
(The details are shown in the figure) is fitted into the center hole 11a of the
They are integrally assembled using positioning pins (not shown) to prevent them from sliding, rotating, or shifting relative to each other. FIG. 4 is a diagram showing the sliding surface of the valve plate 11, and shows the high pressure side port 30 and the low pressure side port 31 provided on the cover 56.
This high pressure side port 30 has the same shape (arc shape) as
, communication holes 30a and 31 that communicate with the low pressure side port 31, respectively.
A is provided. Here, the groove width H of the communication hole 30a communicating with the high-pressure side port 30 is narrower than the groove width l of the communication hole 31a communicating with the low-pressure side port 31, and the communication hole 31a is connected to the cylinder block 12 which will be described later. The communication hole 30a communicates with the balance groove 12a provided in the groove width H.
Since it is narrow, it does not communicate with the balance groove 12a. Valve plate 1
The direction of rotation of the cylinder block 12 with respect to the notch 90 is clockwise in FIG. .91 is provided.

A balance groove 11b is provided on the surface of the valve plate 11 facing the cover 56.

The cylinder block 12 has the same number of plunger chambers 12c as the plunger ports 12b provided in the cylinder block 12 to communicate the high-pressure side port 30 and the low-pressure side port 31 with each plunger chamber 12c. A plunger 13 is slidably housed in each plunger chamber 12c.The sliding surface of the cylinder block 12 with the valve plate 11 has a diameter as shown in FIG. Two ring-shaped balance grooves 12a of different sizes, a plunger port 12b, a pin hole 12d for passing the pin 44, and oil leaking toward the shaft 15 from between the cylinder block 12 and the valve plate 11 of the low-pressure side port 31 are drained into the case chamber. A small hole 12e is provided for returning the plunger boat 1 to the plunger chamber 12C.
2b, when the cylinder block 12 rotates,
It communicates alternately with the communication holes 30a and 31a of the valve plate 11. As can be seen from FIG. 1, the balance groove 12a is provided coaxially on the inside and outside of the plunger boat 12b, and does not communicate with the communication hole 30a of the valve plate 11 described above, but does not communicate with the communication hole 31a. It has a continuous sliding structure. The head 13a of each plunger 13 is spherical as shown in FIG. 1, and a shoe 50 is separately and slidably assembled to each head 13a. The shoe 50 is in sliding contact with the swash plate 14 and slides on the swash plate 14 as the cylinder block 12 rotates. A spring 41 is provided inside the cylinder block 12, and one end of the spring 41 is connected to a plate 42.
, the cylinder block 12 is biased toward the valve plate 11 through a circlip 43, and the other end biases a stopper 45 through a plate 42 and a pin 44. A spherical portion is provided on the outer surface of the stopper 45 and is slidably fitted to the spherical inner surface of the shoe holder 46. The biasing force applied to the stopper 45 is applied to the shoe 50 via the shoe holder 46.
is urged toward the swash plate 14 side. A drain boat 32 is provided in the housing 57 and maintains the case chamber 17 at drain pressure. A ring-shaped seal packing 58 is provided between the cover 56 and the housing 57 to keep the case chamber 17 oil-tight.

Next, regarding the first embodiment of the present invention having the above structure, the first
The operation will be explained using the diagram and FIG. FIG. 2 is a sectional view taken along the line AA in FIG. 1. By oil pump 1,
When high-pressure oil is fed from the reservoir tank 55 to the high-pressure side boat 30 of the axial piston motor 10 on the upstream side, the high-pressure oil passes through the communication hole 30a of the valve plate 11 and the plunger boat 12b and is forced into the plunger chamber 12c. be done.

As a result, the plunger 13 is pushed in the direction of the swash plate 14,
Since the swash plate 14 is inclined as shown in FIG. 2, the shoes 50 tend to move along the inclination of the swash plate 14, and rotational torque is generated in the cylinder block 12, causing it to rotate.

Since the shaft 15 is fitted into the cylinder block 12 through the spline portion 15b, the shaft 15 rotates integrally with the cylinder block 12. For this reason, slippage occurs between the cylinder block 12 and the valve plate 11 and between the swash plate 14 and the shoe 50. Leakage of pressure fluid between the plunger 13 and the cylinder block 12 and between the shoe 50 and the swash plate 14 is relatively small.
The leakage of pressure fluid from the portion between the plunger boat 12b and the communication hole 30a increases. This plunger boat 1
Pressure liquid leaking from the portion between the communication hole 30a and the communication hole 30a flows into the low-pressure side boat 31 from the communication hole 31a via the balance groove 12a.

Next, the effects of the first embodiment described above will be shown in comparison with the effects of the prior art. In the prior art shown in Fig. 6,
Since the balance groove 204 communicates with the case chamber 206, the pressure fluid leaking from between the cylinder block 200 and the valve plate 202 flows into the case chamber 206 and then flows into the case chamber 206.
06 was returned to the reservoir tank 210 from the drain port 208 in order to maintain the drain pressure. However, in a system in which multiple hydraulic motors are connected in series, the sum of the operating differential pressures of each motor is applied to the high-pressure side hoard of the upstream axial piston motor, so leakage of pressure fluid becomes extremely large. Put it away. Now, the operating differential pressure of the upstream axial piston motor is ΔPI, the operating differential pressure of the downstream axial piston motor is ΔP 2 , and the pressure fluid from the high-pressure side boat between the cylinder block and valve plate in the upstream axial piston motor Let Q2 be the leakage amount, and Q3 be the pressure fluid leakage N from other parts (the amount of pressure fluid leakage from the low-pressure side boat, etc. between the shoe and the swash plate, between the plunger and the cylinder block, and between the cylinder block and the valve plate). Conventionally, the power loss due to pressure fluid leak in the upstream axial piston motor is (Qz + Qi ) × (ΔP1 + ΔP2
).

On the other hand, in the first embodiment of the present invention, the amount of pressure fluid leaked from the drain port 32 of the upstream axial piston motor 10 is Q3, and the power loss due to this is Q,
(ΔP, +ΔP2).

On the other hand, the amount of pressure fluid leaking from the portion between the plunger port 12b and the communication hole 30a between the cylinder block 12 and the valve plate 11 and flowing into the low pressure side port 31 from the communication hole 31a via the balance groove 12a is Q. The power loss is Q2×ΔP.

Therefore, the power loss of the upstream axial piston motor 10 in this embodiment is Q, × (Δp, +ΔP2) + Q
zXΔPt, and compared with the prior art, Q,
An excellent effect is achieved in that the power loss corresponding to ×ΔPt can be reduced.

Furthermore, since the drain flow rate is reduced, the drain boat and drain piping can be downsized.

Next, a second embodiment of the present invention will be described using FIG. 5. Note that the same components as in the first embodiment are given the same reference numerals as in FIG. 1. In this embodiment, the shaft 15
A ring-shaped pressure chamber 101 is provided between the cylinder block 12 and the cylinder block 12 to increase the force pressing the cylinder block 12 against the valve plate 11. The shaft 15 includes a spline portion 15b and fitting portions 15c and 15c having mutually different diameters.
5d, and is fitted to the cylinder block 12 at the spline portion 15b and fitting portions 15c and 15d. O rings 1 are attached to the fitting parts 15c and 15d of the shaft 15.
02.103 is provided to maintain liquid tightness. Fitting parts 15c and 15d of shaft 15 and cylinder block 1
2 forms a pressure chamber 101, and a pressure introduction hole 100 is provided at the end of the shaft to communicate the pressure chamber 101 and the high pressure side boat 30. Therefore, when hydraulic pressure acts on the high-pressure boat 30, the hydraulic pressure also acts on the pressure chamber 101, increasing the force that presses the cylinder block 12 toward the valve plate 11. At this time, since hydraulic pressure acts on the shaft 15 in the left direction in FIG. 5, the thrust load (force in the axial direction) is supported by the tapered roller bearing 104. The bearing 105 at the other end uses a journal bearing to prevent leakage of pressure fluid.

In this embodiment, the pressure chamber 101 and the high-pressure side boat 30 are communicated with each other, but the present invention is not limited to this, and the pressure chamber 101 and the low-pressure side port 31 may be communicated with each other.

Furthermore, in the first and second embodiments described above, the balance groove between the cylinder block and the valve plate, which is the main part of the present invention, was provided on the cylinder block side, but instead it was provided on the valve plate 11 side. Good too.

In addition, although we have shown an example in which another axial piston motor is connected downstream of the upstream axial piston motor,
Examples of devices connected to the downstream side include devices that obtain mechanical energy by using the residual pressure of the liquid discharged from the low-pressure side port of the upstream axial piston motor, such as hydraulic cylinders or devices with a throttle. If so, something else is fine.

Further, the liquid used is not limited to oil, and other liquids such as water may be used.

〔Effect of the invention〕

As explained above, according to the present invention, a ring-shaped groove is provided on the sliding surface of the cylinder block and the case and communicates only with the second hole (low-pressure side). Since the high-pressure liquid leaking from between the casing and the casing is guided to the second hole, it is possible to provide an axial piston motor that can reduce power loss.

In addition, a space is provided between the shaft and the cylinder, and the first
Alternatively, since the cylinder block is communicated with the second hole, the cylinder block does not separate from the case.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, and FIG. 2 is a diagram showing its A.
-A sectional view, Figure 3 is a diagram showing the cylinder block, Figure 4 is a diagram showing the cylinder block.
The figure shows a valve plate, FIG. 5 shows a second embodiment of the present invention, and FIG. 6 shows a conventional axial piston motor. 12... Cylinder block, 12a... Balance groove. 15...Shaft, 30...High pressure side boat, 31.
...Low pressure side port, 56...Cover, 57...Housing.

Claims (2)

[Claims] (1) An axial piston motor that drives a cylinder block using liquid pressure to rotate a shaft, which includes a case that pivotally supports the shaft and surrounds the cylinder block, and a high-pressure liquid that is applied to the cylinder block from the outside of the case. a first hole provided in the case for supplying low-pressure liquid from the cylinder block to the outside of the case; a second hole provided in the case for discharging low-pressure liquid from the cylinder block to the outside of the case; A ring-shaped groove is provided on a sliding surface of the cylinder block and the case that is in contact with the first and second holes, and communicates only with the second hole. Axial piston motor. (2) A claim comprising: a predetermined space provided between the shaft and the cylinder block; and a communication hole that communicates the space with the first or second hole. The axial piston motor according to item 1.