JPS6311351Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a variable displacement vane pump, and in particular, the rotor supporting the vane is housed within the inner periphery of a cam ring, and the cam ring is operated by an actuator that operates according to discharge pressure. The present invention relates to a variable displacement vane pump that changes the amount of eccentricity between the inner periphery of the cam ring and the rotor by rotating to vary the discharge amount of the pump.

As a variable displacement vane pump of this type, there is a conventional type disclosed in Japanese Patent Application Laid-Open No. 58-104383, in which the pump discharge pressure acts on an actuator. However, since a vane pump pressurizes and discharges the hydraulic fluid introduced into the pump by the rotation of radially arranged vanes, this discharge pressure includes a pulsating element generated by each discontinuous vane. It will be done. On the other hand, the actuator is also constantly operated to change the amount of rotation of the cam ring in response to variations in the pump discharge pressure due to changes in the rotational speed of the rotor, and the operation of the actuator becomes a kind of pulsating state. Therefore, if the pulsation caused by the vane and the pulsation caused by the actuator interfere with each other, it will be as if an incorrect discharge pressure is acting on the actuator, and accurate control of the discharge amount of the variable displacement vane pump will not be performed. Therefore, conventionally, a frictional resistance is provided between the cam ring and the housing in which the cam ring slides, and this resistance force reduces the influence of the pulsation on the cam ring operation. However, with a device that suppresses malfunction by simply applying frictional resistance to the cam ring, there is a problem that the cam ring does not operate smoothly when a sudden increase in the discharge amount is required. Ta.

Purpose of the invention In view of these conventional problems, the present invention prevents malfunction of the cam ring and reduces the discharge amount by eliminating the pulsation of the pump discharge pressure in the passage that supplies the discharge pressure to the actuator. It is an object of the present invention to provide a variable displacement vane pump that can respond to rapid increases in demand.

Structure of the Invention In order to achieve the above object, the present invention provides a rotor that supports a plurality of vanes in a radial and slidable manner, a rotor that is eccentrically housed within the inner circumference, and a point that is offset from the center of the inner circumference. A cam ring that rotates around , and is biased in the direction of maximum eccentricity by a spring, an actuator that adjusts the rotation of this cam ring in a direction to reduce the amount of eccentricity using pump discharge pressure, and a pump discharge to the actuator. A one-way orifice that acts on the flow from the pump body toward the actuator is provided in the pressure supply passage.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of a variable displacement vane pump 1 of the present invention, and an example will be described in which the pump is used for supplying hydraulic fluid to an automatic transmission. That is, in the variable displacement vane pump 1, a housing part 3 is formed in a casing 2 which houses a torque converter (not shown) as a housing, and a rotor 4 and a rotor 4 eccentrically located on the outer circumference of the rotor 4 are formed in the housing part 3. The cam ring 5 and the like to be arranged are housed therein. Rotor 4
A hollow drive shaft 6 connected to an engine (not shown) is locked in the center of the rotor 4, and the rotor 4 is rotated via this drive shaft 6 as the engine rotates. Further, a plurality of slits 4a are formed radially on the peripheral edge of the rotor 4, and a vane 7 is slidably inserted into each of the slits 4a. The vanes 7 are each urged in the outer radial direction, and their tips are slidably brought into close contact with the inner periphery 5a of the cam ring 5. One end of the cam ring 5 is rotatably attached to the casing 2 via a pin 8, and by rotating the cam ring 5 around the pin 8, the cam ring 5 and the rotor 4 are connected to each other.
The discharge amount is adjusted by changing the amount of eccentricity between the two. Further, an arm portion 9 is provided protruding from the other end of the cam ring 5, and the lower side of the arm portion 9 is urged upward by a compression spring 10, that is, in the maximum eccentric direction of the cam ring 5, and the upper side of the arm portion 9 is biased upwardly by a compression spring 10. An operating rod 21 that is moved up and down by an actuator 20
The eccentricity of the cam ring 5 is determined by the operating rod 21 pressing the arm portion 9 against the biasing force of the compression spring 10. Further, a suction port 12 and a discharge port 11 are formed on the inner circumference of the cam ring 5 to face each other,
As the rotor 4 rotates, the hydraulic fluid introduced into the pump chamber 13 from the suction port 12 is pressurized and supplied from the discharge port 11 to the torque converter and each control valve.
Furthermore, a plurality of grooves 30 are formed on the outer periphery of the suction port 12 of the cam ring 5 to prevent sticking due to twisting of the cam ring. The hydraulic fluid leaked from the cam ring 5 accumulates in the gap 2a between the cam ring 5 and the casing 2, and acts as lubricating oil due to the groove. The hydraulic fluid accumulated in the gap 1a is discharged from a drain hole provided above the housing portion 3 of the casing 2. Incidentally, the discharge pressure discharged from the discharge port 11 is supplied to the actuator 20 via the pressure regulator valve P to operate the actuator 20. That is, the actuator 2
The discharge pressure introduced into the introduction passage 22 is supplied to the cylinder chamber 23 and acts as a force that presses the free piston 24 downward. This free piston 24 is moved downward by the increase in discharge pressure at this time when the rotor rotates faster due to high rotation of the engine, and this movement amount is transmitted through the operating rod 21 to the downward rotation amount of the cam ring 5. The discharge amount of the variable displacement vane pump 1 is controlled to be reduced. Conversely, when the rotor's four rotations slow down, the free piston 24 is moved in a direction (upward) that increases the discharge amount.

Here, in this embodiment, a one-way orifice 30 is provided in the introduction passage 22 of the actuator 20, which acts on the flow from the pump body 1a toward the actuator 20. That is, the one-way orifice 30 can be brought into close contact with the periphery of the upper step 25a of the large diameter section 25 formed in the introduction passage 22, and a movable plate 31 is provided with a gap between it and the inside of the large diameter section 25. and a spring 32 that urges the movable plate 31 upward, and an orifice 33 is formed in the center of the movable plate 31. Therefore,
When the pump discharge pressure becomes high, the hydraulic fluid discharged from the discharge port 11 flows from the pump body 1a toward the actuator 20, so the movable plate 31 is brought into close contact with the upper step 25a, and the hydraulic fluid flows through the orifice 33. It will only pass through.
On the other hand, when the pump discharge pressure becomes low, the hydraulic fluid flows from the actuator 20 toward the pump body 1a, so the movable plate 31
2, the hydraulic fluid passes through the gap between the orifice 33 and the periphery of the movable plate 31, and the passage area is significantly increased. Therefore, the vane 7 of the vane pump 1
The pulsations caused by this are removed when the hydraulic fluid passes through the orifice 33, thereby preventing the actuator 20 from erroneously operating the cam ring 5. On the other hand, even when the rotational speed of the rotor 4 suddenly decreases, the operation of increasing the discharge amount of the cam ring 5 must be performed quickly. Since the area is increased, the hydraulic fluid flows smoothly from the actuator 20 toward the pump body 1a, and the cam ring 5 can be quickly operated in the direction of increasing the discharge pressure.

By the way, the pulsation removal function of the orifice 33 is achieved by the flow of the working fluid through the orifice 33, but the pump discharge pressure is constantly fluctuated as the engine rotation is slightly changed. Therefore, the pulsation removal function by the orifice 33 is sufficiently performed.

FIG. 2 shows another embodiment, in which the actuator 2
A relief valve 40 is provided in the introduction passage 22 of 0 in parallel with the one-way orifice 30 to allow the flow of working fluid from the pump body 1a toward the actuator 20, and the biasing force of the spring 41 of this relief valve 40 is set to be large. . The variable displacement vane pump 1' of this embodiment is schematically shown.
Components that are the same as those in the previous embodiment are given the same reference numerals and explained.

In this embodiment, when the pump discharge pressure rapidly increases as the engine rotates during sudden acceleration, this discharge pressure does not pass through only the orifice 33 of the one-way orifice 30, but instead passes through the relief valve 40. Since the actuator 20 is operated by opening the pump, it is possible to control the pump discharge amount when the torque suddenly increases. Incidentally, during gentle acceleration, the relief valve 40 is not opened.
The hydraulic fluid moving toward the actuator 20 passes only through the orifice 33 and exhibits the pulsation eliminating function as shown in the embodiment.

Each of the above-mentioned embodiments has been described using a variable displacement vane pump used in an automatic transmission as an example, but the invention is not limited to this, and it can also be applied to a general type vane pump in which the discharge amount is controlled according to four rotations of the rotor. It goes without saying that the present invention can be applied to variable displacement vane pumps.

Effects of the Invention As explained above, in the variable displacement vane pump of the present invention, when pump discharge pressure including pulsations generated by vane rotation is supplied to the actuator, the pulsations are removed by the one-way orifice. Malfunctions caused by the actuator are prevented,
Accurate discharge amount control can be performed. Also,
Since the one-way orifice does not function as an orifice for a flow in the opposite direction, the actuator is operated quickly in the direction of increasing the discharge amount to maintain the required predetermined pump discharge amount even when the rotation of the rotor suddenly decreases. This has the excellent effect of being able to secure it quickly.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a variable displacement vane pump showing one embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of a variable displacement vane pump showing another embodiment of the present invention. 1, 1'...variable displacement vane pump, 1a...
...Pump body, 2...Casing (housing),
4... Rotor, 5... Cam ring, 7... Vane, 11... Discharge port, 12... Suction port,
13... Pump chamber, 20... Actuator, 3
0...One-way orifice.

Claims (1)

[Scope of utility model registration request] A rotor that supports a plurality of vanes in a radial and slidable manner, and this rotor is housed eccentrically within the inner periphery, rotates around a point off the center of the inner periphery, and is attached by a spring in the direction of maximum eccentricity. A cam ring that is energized, an actuator that rotates the cam ring in a direction to reduce eccentricity using pump discharge pressure, and a passage that supplies pump discharge pressure to the actuator from the pump body toward the actuator. A variable displacement vane pump characterized by having a one-way orifice that acts on the flow of water.