JPS6240147Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a vane pump equipped with a pressure reducing valve that can reduce noise.

Instead of forming the back pressure grooves on the rotor contacting surfaces of the pressure plate and side plate of conventional vane pumps into annular grooves, vane back pressure grooves are formed independently in the suction section and the discharge section, respectively, so that the adjacent back pressure grooves are formed in the suction section and the discharge section. When attempting to reduce the phenomenon in which the vane tip impacts the inner surface of the cam ring and generates noise by connecting the pressure grooves with a small groove, such a configuration reduces the vane back pressure that has been reduced in the suction section. However, if the cross-sectional area of the small groove is not determined with sufficient accuracy, the vane will move away from the suction section back pressure groove due to the pressure difference between the suction section vane back pressure groove and the discharge section vane back pressure groove. A sudden pressure change occurs in the vane back pressure acting on the lower end of the vane in the back pressure groove of the discharge section or in the process of transitioning from the back pressure groove of the discharge section to the back pressure groove of the suction section.
The tip of the vane may strike the inner surface of the cam ring, producing noise and causing wear on both the vane and cam ring contact surfaces.

This invention was made in order to eliminate the drawbacks of the prior art described above, and in the pressure plate and side plate of the vane pump, or the rotor contacting surface of the side plate or a corresponding portion thereof, the suction section is placed at the lower end of the vane groove of the suction section and the discharge section. A vane back pressure groove and a discharge section vane back pressure groove are independently bored, and the discharge section vane back pressure groove is communicated with the discharge port through a substantially unrestricted passage, and the pressure oil of the discharge port is A portion of the pressure is reduced by an attached pressure reducing valve and introduced into the suction section vane back pressure groove through another passage substantially without restriction, and all adjacent back pressure grooves are connected at the rotor contact surface. These back pressure grooves are connected to each other by small grooves with the minimum microchannel cross-sectional area necessary to create a gradient pressure distribution, and the vane back pressure grooves in each section of suction and discharge are By making these independent and guiding the discharge pressure from the discharge ports, the pressure oil can be replenished from the discharge ports for the vane lift in the suction section and for the pressure oil leaking from the vane back pressure groove in the section through the vane sliding gap, etc. The pressure is directly applied to the vane back pressure groove through the pressure reducing valve, and the oil leakage from the independent back pressure groove is sufficiently compensated for by the inflow of pressure oil due to the lift down of the vane, so that the pressure exceeds the discharge pressure. The vane is brought into contact with the cam ring securely in each section from no-load to high-pressure by increasing the back pressure of the vane. This makes it possible to create a gradient in the change in vane back pressure between the suction and discharge sections, thereby reducing noise generation in the high-pressure vane pump and effectively preventing wear on the inner surface of the cam ring and the tip of the vane.

If we explain the embodiment of this invention with reference to the drawings,
In FIGS. 1 and 2, a rotor 2 fixedly fixed and rotating together is arranged in a casing 38 in which a body 30 and a cover 31 are connected with a tightening bolt 34, and a plurality of radial vane grooves 19 bored in the outer periphery of the rotor 2 are arranged. The vane 3 is slidably inserted into the body 3 of the rotor.
A pressure plate 20 is disposed on the 0 side in contact with the rotor, and a cover sliding surface 18 is disposed on the cover 31 side of the rotor 2 in contact with the rotor. The outlet 32 communicates with the suction port 4, and the discharge port 5 communicates with the discharge port 33 that discharges hydraulic oil to the outside. A suction section vane back pressure groove 6 and a discharge section vane back pressure groove 7 are independently bored at the lower end of the vane groove of the section to form a seal section between each back pressure groove, and the discharge section vane back pressure groove is a passage. 11 communicates with the discharge port 5, and the suction section vane back pressure groove communicates with a large diameter chamber 35 of the pressure reducing valve 9, which will be described later, with a passage 12, and both adjacent vane back pressure grooves communicate with the small groove 10. Each is connected. The pressure reducing valve 9 is the cover 3
1, the piston 40 consists of a large diameter part 41 and a small diameter part 42, the former having a large diameter part chamber 35.
The latter is inserted into a small diameter chamber 36, which is communicated with the atmosphere through a drain passage 16, and an oil chamber 37 is formed between the two chambers.
3 is connected to the discharge port 5. Note that if the cross-sectional area of the small groove 10 is too small, a pressure drop will occur in the seal section, and if it is too large, a pressure oil flow will occur and the vane back pressure in the discharge section will be lower than the discharge pressure. It is necessary to make the passage cross-sectional area as small as possible to compensate for oil leakage in the seal section and create a gradient pressure distribution between the back pressure grooves of the rotor contact surface.

Note that 17 indicates a drain passage communicating with the suction port 4, and 8 indicates the bottom volume of the vane groove 19.

Therefore, the hydraulic oil sucked in from the suction port 32 flows through the suction port 4 provided in the pressure plate 20 and the cover 31, and then flows into the discharge port 5.
It is supplied to the hydraulic equipment from the discharge port 33 through the
The pressure oil is introduced into the pressure reducing valve 9 through the passage 13 and is reduced in pressure. The reduced pressure is determined by the cross-sectional area ratio of the piston large diameter section 41 and small diameter section 42, and this reduced secondary pressure is introduced into the suction section vane back pressure groove 6 through the passage 12 and pushes up the vane 3. , Pressure oil discharged from the discharge section vane back pressure groove 7 by the discharge action of the lower part of the vane 3 is introduced into the discharge port 5 via the passage 11, and the small groove 10 between the adjacent back pressure grooves.
Therefore, due to the pressure difference between the primary pressure of the discharge section vane back pressure groove 7 and the secondary pressure of the suction section vane back pressure groove 6, a small flow rate flows from the small groove to the secondary pressure side. Between the back pressure grooves, there is a small diameter section A and a large diameter section B of the cam ring, as shown in curve a in Fig. 4.
Since a pressure distribution with a continuous pressure gradient is obtained in As a result, the vane 3 moves between the vane grooves 19, so that the tip of the vane 3 does not impact the inner surface of the cam ring 1.

In addition, in FIG. 4, curve C is the pressure distribution when there is no small groove, and even if both back pressure grooves are connected with a V notch 14 as shown in FIG. 3 instead of the small groove 10, the As shown by curve b in FIG. 4, the pressure distribution is almost the same as that of the small groove described above, and the effect is the same.

Further, although the pressure reducing valve 9 is shown as a constant ratio pressure reducing valve in the illustrated example, it may be of a fixed pressure reducing type or a constant difference type.

As mentioned above, according to this invention, it is possible to reduce the noise generated by high-pressure vane pumps and to significantly prevent wear on the inner surface of the cam ring and the tips of the vanes. It is possible to construct the vane pump from a material with good workability even if it is not made from a hard material, and on the other hand, if it is constructed from a similar wear-resistant material, it is possible to obtain a vane pump for higher pressure.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional side view showing an embodiment of this invention, Fig. 2 is an explanatory cross-sectional view taken along line A-A in the previous figure, and Fig.
The figure is an enlarged partial plan view showing another example of connecting back pressure grooves, and FIG. 4 is a curve diagram showing the pressure distribution between the back pressure grooves. 1...Cam ring, 2...Rotor, 3...Vane, 4...Suction port, 5...Discharge port, 6...
...Suction section vane back pressure groove, 7...Discharge section vane back pressure groove, 9...Pressure reducing valve, 10...Small groove, 14...
V notch, 19... vane groove, 20... pressure plate, 31... cover, 32... suction port,
33...Discharge port.

Claims (1)

[Scope of utility model registration request] In the rotor contacting surface of the pressure plate and the side plate, suction section vane back pressure grooves and discharge section vane back pressure grooves are independently bored at the lower ends of the vane grooves of the suction section and the discharge section, respectively, to reduce the vane back pressure of the discharge section. The groove is communicated with a discharge port through a substantially unrestricted passage, and a portion of the pressure oil in the discharge port is reduced in pressure with an attached pressure reducing valve, and then the pressure oil is communicated with the discharge port through another passage without restriction. The minimum fine flow path required to be introduced into the back pressure groove of the suction section vane and to create a pressure distribution with a gradient between all adjacent back pressure grooves at the rotor contact surface. A vane pump characterized in that small grooves having a cross-sectional area communicate with each other.