JPH0219595Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a thrust load receiving device for a diagonal shaft piston pump and motor, and more specifically, in a diagonal shaft piston pump and motor having two ports, the pressure increase in one port is When it is hot, this pressure is guided to the end face of the cylinder casing on the other side,
The present invention relates to a thrust load receiving device capable of receiving a thrust load on a cylinder casing.

In general, a diagonal shaft type piston pump has a cylinder casing disposed within a housing via a bearing, and the cylinder casing is swung around the bearing as a central axis to select the discharge amount of the pump.

For example, as a conventional piston pump and motor of this kind, one disclosed in Japanese Utility Model Application Publication No. 1983-55603 is known. As shown in Fig. 3, this piston pump and motor includes a cylinder casing C that is swingably disposed inside a casing A via a bearing B, and has a suction port D and a discharge port E inside the cylinder casing C. The suction port D and the discharge port E are connected to the suction port G and the discharge port H provided on the valve plate F, respectively, and as the main shaft I rotates, the cylinder block J is rotated, and suction is taken from the suction port D. The liquid is pressurized and discharged to the discharge port E.

Moreover, in such piston pumps and motors, when the pressure at the discharge port E increases, a downward pressing load is generated on the outer end surface of the cylinder casing C due to this pressure, and the cylinder casing C is pressed below the casing A. This causes a rocking failure of the cylinder casing C.

For this reason, in order to avoid this rocking defect, conventionally,
For example, a bearing formed by a tapered roller may be inserted at the opposite position facing the discharge port E to receive and balance the above-mentioned pressing load, or the pressure of the discharge port E may be transferred from the discharge port E to the cylinder casing C via a branch circuit. The load on the discharge port side is balanced by the surface pressure on the opposite side.

However, this method of guiding hydraulic pressure to the other end of the cylinder casing using a branch circuit and receiving a load from the surface pressure to cancel out the reaction force due to the discharge pressure at the discharge port is limited to having one discharge port and discharging only from one side of the cylinder casing. It can be used with certain pumps and motors, but when there are two discharge ports, such as vehicle pumps, and they are selectively used for suction and discharge during forward and reverse rotation, it is necessary to balance them hydraulically. It is something that cannot be taken.

Therefore, the purpose of this invention is to create a diagonal piston pump with two discharge ports that can be used selectively for suction and discharge, and even with a motor, it can be balanced by hydraulic pressure and the cylinder casing can swing smoothly. An object of the present invention is to provide a thrust load receiving device for a pump or motor.

In order to achieve this objective, the present invention includes a cylinder casing disposed in a housing so as to be swingable via a bearing, two passages vertically opposed to each other being bored in the cylinder casing, and two passages arranged vertically opposite each other. is selectively used for suction and discharge, and furthermore, a cover arranged around the outer periphery of the cylinder casing is provided with two vertically opposing ports, and each port is communicated with one of the two passages. In the motor, a high-pressure seal is interposed between each port and the mouth end of each passage, and the high-pressure seal is formed with a through hole that communicates the port with the passage, and the discharge pressure from the passage is applied to the outer end surface of the high-pressure seal. In addition, an auxiliary seal is installed around the high pressure seal,
It is characterized in that the discharge pressure of one port is guided to the end face of the auxiliary seal on the other port side through branch passages.

According to the above configuration, when one port becomes high pressure, this high pressure acts on one end face of the cylinder casing and pushes down the cylinder casing, but this high pressure is applied to the cylinder through one branch passage and one auxiliary seal. It also acts on the other end of the casing, and similarly when the other port becomes high pressure and pushes up the cylinder casing, the high pressure of this port acts on one end of the cylinder casing via the other branch passage and the other auxiliary seal. Then, the reaction force due to the discharge pressure of each port is canceled out.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A cylinder casing 4 is swingably disposed within a housing 1 of a pump or motor via bearings 2 and 3 to select, for example, the discharge amount of the pump.

A cylinder block and a swash plate 9 are rotatably disposed inside the cylinder casing 4, and an input shaft 10 is connected to this cylinder block.
It is rotatably inserted into the housing 1 via.

A cover 15 communicates with the housing 1 via a pin 31, and the input shaft 10 is supported by a bearing 13 and a seal 14 inside the cover 15.
An auxiliary pump 16 is disposed between the cover 15 and the cover 15.

Discharge passages 17 and 18 are formed in opposite directions within the cylinder casing 4, and these passages 17,
18 is open on both upper and lower end surfaces of the cylinder casing 4. Each of the discharge passages 17 and 18 is selectively used as a suction passage and a discharge passage during normal rotation and reverse rotation, respectively.

A cover 19 is disposed around the outer periphery of the housing 1 and the cylinder casing 4, and the inner end surface of the cover 19 is brought into close contact with both upper and lower end surfaces of the housing 1 and the cylinder casing 4.

The cover 19 has two independent e.g. discharge ports 20 and 21 facing the mouth ends of the passages 17 and 18.
and connect these ports 20, 21 to passages 17,
18 respectively.

A high-pressure seal 22 is interposed between the mouth end of the port 20 and the mouth end of the passage 17, and a through hole a is formed in the center of the high-pressure seal 22 to communicate the port 20 and the passage 17. An auxiliary seal 23 is provided on the outer periphery of the high pressure seal 22. These seals 22, 23
The end face is in close contact with the upper end face of the cylinder casing 4 to prevent leakage from the port 20, passage 17, and branch passage 27.

As shown in FIG. 2, the high-pressure seal 22 consists of a washer a, a high-pressure resin seal b, and a metal seal c stacked one on top of the other, and pressed against the cylinder casing 4 by the force of a wave spring d. Similarly, the auxiliary seal 23 is composed of a washer e, a resin seal, a metal seal g, and a wave spring h that presses these down.
In the high pressure seal 22, the metal seal c and the cover 1
The resin seal b seals the gap between the discharge port 20 and the discharge port 20, thereby preventing oil from the discharge port 20 from leaking to the outside. In the auxiliary seal 23, the metal seal g
The gap between the cover 19 and the cover 19 is sealed with a resin seal f to prevent oil flowing from the branch passage 27 from flowing outside.

Similarly, a high-pressure seal 24 is interposed between the mouth end of the other port 21 and the mouth end of the passage 18, and a through hole is formed in the center of the high-pressure seal 24 to communicate the port 21 and the passage 18. Pressure is applied to its outer end surface, and an auxiliary seal 23 is further provided on the outer periphery of the high pressure seal 24. The port 21, whose end surface is in close contact with the lower end surface of the cylinder casing 4,
Oil leakage from the passage 18 and branch passage 26 is prevented.

On the other hand, the upper port 20 and the lower auxiliary seal 25
A branch passage 26 is provided between the lower port 21 and the upper auxiliary seal 23 to communicate with each other, and a branch passage 27 is interposed between the lower port 21 and the upper auxiliary seal 23 to communicate with each other. The lower end surface of the cylinder casing 4 is received via the seal 25, and similarly, the high pressure of the lower port 21 is received by the upper end surface of the cylinder casing 4 via the upper auxiliary seal 23.

Note that 28, 29, and 30 are passages.

Next, let's talk about thrust force.

It is assumed that oil is sucked in from the discharge port 21, pressurized inside the pump body, and then high-pressure oil is discharged from the discharge port 20, and the diameters of the ports 20 and 21 are d,
The diameter of the lower high pressure seal 24 is d ₁ , the diameter of the upper high pressure oil 22 is d ₂ , and the diameter of the lower auxiliary seal 25 is
When D ₁ and the diameter of the upper auxiliary seal 23 are D ₂ ,
When oil is discharged from the discharge port 20, the cylinder casing 4 is pushed downward by a thrust force of F=π(d ₂ ² −d ² )/4×pressure (where F is the pressing load).

On the other hand, the lower end surface of the pressed cylinder casing 4 supports the thrust force with an area of A=π(D ₁ ² −d ₁ ² )/4 (where A is the cross-sectional area of the auxiliary seal that supports the pressing load). Therefore, if it is designed so that π(d ₂ ² −d ² )/4=π(D ₁ ² −d ₁ ² )/4, the pushing down force and pushing up force cancel each other out.

In the above pumps and motors, passages 17 and 18 are bored in vertically opposing positions in the cylinder casing 4, and ports 20 and 21, high pressure seals 22 and 24, and auxiliary seals 23 and 25 are provided opposite these passages 17 and 18. Because one port is connected to the auxiliary seal end face on the other port side via a branch passage, when the upper port 20 becomes high pressure, this high pressure pushes the cylinder casing 4 downward, but this high pressure is branch passage 26, auxiliary seal 2
Similarly, when the lower port 21 becomes high pressure and pushes the cylinder casing 4 upward, the high pressure of the port 21 is applied to the branch passage 27 and the auxiliary seal 23.
acts on the upper end surface of the cylinder casing 4 via the radiator 4, thereby canceling out the reaction forces caused by the discharge pressures of the ports 20 and 21, respectively.

According to the present invention, even when there are two discharge ports, the cylinder casing can swing smoothly, and the thrust receiving means such as a bearing is simple and does not require special processing or strength.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway longitudinal sectional front view of a diagonal shaft type piston pump according to an embodiment of the present invention, Fig. 2 is an enlarged sectional view of the upper seal portion, and Fig. 3 is a longitudinal sectional view of a conventional pump and motor. It is a front view. 1... Housing, 2, 3... Bearing, 4
... Cylinder casing, 17, 18 ... Passage,
19...Cover, 20, 21...Port, 22,
24... High pressure seal, 23, 25... Auxiliary seal, 26, 29... Branch passage.

Claims (1)

[Claims for Utility Model Registration] (1) A cylinder casing is disposed in a housing so as to be able to swing freely via a bearing, and two passages are bored in the cylinder casing vertically facing each other. is selectively used for suction and discharge, and furthermore, a cover arranged around the outer periphery of the cylinder casing is provided with two vertically opposing ports, and each port is communicated with one of the two passages. In the motor, a high-pressure seal is interposed between each port and the mouth end of each passage, and the high-pressure seal is formed with a through hole that communicates the port with the passage, and the discharge pressure from the passage is applied to the outer end surface of the high-pressure seal. A thrust load receiving device for a pump or a motor, in which an auxiliary seal is provided on the outer periphery of the high-pressure seal, and the discharge pressure of one port is guided to the end face of the auxiliary seal on the other port side via branch passages. (2) A thrust load receiving device for a pump or motor according to claim 1, wherein the port and the seal are provided on the side of the cover that is in close contact with the cylinder casing.