JPS6075780A - Capacity controller for variable capacity pump - Google Patents

Abstract

PURPOSE:To certainly prevent the seizure of an operating rod, etc. by forming a small communication hole by which fluid control pressure is not influenced, onto a piston for controlling pump capacity and lubricating a slidable part by the fluid which leaks from said opening. CONSTITUTION:A capacity controller 1 in a rotary-vane type variable capacity pump 2 is constituted of a cylinder 13 installed onto a pump housing 3 by bolts 12, capacity control piston 14 inserted in slidable ways into a cylinder opening 13a, and an operating rod 15 connected to the piston. The pressure chamber 17 in the cylinder 13 is connected to a fluid control pressure supplying source through a passage 19, and a drain chamber 18 communicates to a drain passage 20. An exceedingly small communication hole 14a by which the fluid control pressure in the pressure chamber 17 is not influenced is formed onto the piston 14, and some amount of fluid is allowed to flow into the chamber 18 from the chamber 17 and lubricates the part between the operating rod 15 and the housing opening 3a.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a capacity control device for a variable displacement pump such as a rotary vane pump or a swash plate pump. A vane pump is normally constructed as shown in Fig.
The pump capacity is changed by rotating and displacing the pump around the pivot pin b21. obtain. 7, when the displacement control device is engaged with the cam ring b and slidably inserted into the hole d of the pump housing C to rotationally displace the cam ring a via the hole d and the operating rod e. fl between? I
There is a risk that the rod e may seize and stick in the hole d due to insufficient sliding. At this time, the cam ring displacement may not accurately correspond to the fluid control pressure in the chamber, but the displacement control may become imprecise.

In order to solve this problem, as shown in Fig. 2, the diameter of the hole d is made larger than the diameter of the operating rod e in order to make sliding contact between the hole d and the actuating rod e, which causes the above-mentioned sticking. One idea is to create a play between the two. However, in this case, the hole d cannot guide the rod e and the υ rod e collapses due to the above play. As a result, the υ piston f also collapses. ,
The seal i is lifted locally as shown in Figure 3.
to make the piston f stick. Therefore, even with this measure, the problem cannot be expected to be solved.

OBJECTS OF THE INVENTION The present invention maintains the relationship between the operating rod and the hole in the pump housing through which it is inserted as shown in Figure 1, but configures a capacity control device to automatically lubricate the sliding contact between the two. The purpose of this study is to solve the above-mentioned problems.

Structure of the Invention For this purpose, the capacity control device of the present invention provides a small communication hole in the piston that does not affect the fluid control pressure described in 111, and uses the fluid leaking from the communication hole to cause the actuating rod and the It is characterized in that it is configured to lubricate the gap between it and the hole through which it is slidably inserted.

Example Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 4 shows a low-revene type variable appearance bong 2 equipped with a capacity control device 1 having an exemplary configuration according to the invention.

First, the pump 2 will be explained. The pump 2 is constructed by housing the following various elements in a pump housing 8. 4 is an annular cam ring as a capacity changing element;
It is pivoted to allow rotational displacement in the directions of arrows α and β. A rotor 6 is disposed within the cam ring 4, and the pump 1 drive shaft 7 is drivingly connected to the non-circular center hole of the rotor 6, so that the rotor 6 can be rotated in the direction of the arrow γ. In addition, ξ with respect to the center C11ri of the cam ring 4 and the center C2 of the rotor 6
only eccentric.

A number of vanes 8 (nine in the illustrated example) are inserted into the rotor 6 so as to be movable in the radial direction of the rotor 6, and a pump chamber 9 is defined between the vanes. Inner ring-shaped grooves 6a are formed on both side surfaces of the rotor 6, and vane rings 10 are fitted into these grooves, so that each vane 8 is inscribed in the cam ring 4.

An arm 4a1 is provided protrudingly on the outer peripheral part of the cam ring 4 that is farthest from the pivot pin 5, and a tuft spring 11 is applied to the arm 4a1.
The cam ring 4 is elastically supported at the illustrated rotation limit position where the eccentricity ξ is maximum.

Next, the capacity control device 1 will be explained. This generally consists of a cylinder 18 attached to the pump housing 3 with a hole 12, a volume control piston 14 slidably fitted into the cylinder hole 18a, and an actuating rod 15 connected to this piston. Configure. Plug the opening of cylinder hole 1 s a
A pressure chamber 17 is set between the piston 14 and the piston 14, and a drain chamber 18 is set on the opposite side of the piston 14 at 11+11. Fluid control pressure is supplied to the pressure chamber 17 through a passage 19, and a seal is provided on the outer periphery of the piston 14 which communicates with the drain passage 20 by slidingly contacting the circumferential surface of the cylinder hole 18a to seal between the two. The piston 14 is further formed with an extremely small communication hole 14a that does not affect the fluid control 1'lE in the chamber 17.
Allow some fluid to leak from the chamber 18 into the chamber 18.

The bushing rod 15 is loosely fitted into the closed end of the cylinder hole 13a with a slight gap 22, and is slidably inserted into the hole 3a provided in the pump housing 3 to penetrate into the pump housing 3. The bushing rod 15 is guided through the hole 3a so as not to move in the radial direction, and the tip of the bushing rod 15 is brought into contact with 1111 of the arm 4a far from the spring 1 and engaged with the stone.

The operation of the above embodiment will be explained next.

When the rotor 6 is rotated in the direction of the arrow γ by the drive shaft 7 of the pump, each pump chamber 9 sucks fluid from this boat while increasing its volume passing through the suction boat 23, and sucking fluid from this boat while decreasing its volume passing through the discharge boat 24. The suction fluid is discharged to perform a predetermined pump action.During this action, the volume change N of the pump chamber 9 is determined by the eccentricity ξ, and the cam ring is at the rotation limit position shown in the figure, where the eccentricity ξ is maximum. Pump capacity is maximum.

If this pump capacity is excessive, fluid control pressure commensurate with the excess will not be supplied from the passage 19 to the pressure chamber 17.
pushes the piston 14 down from the position shown. As a result, the cam ring 4 is rotationally displaced around the pin 5 in the direction of the arrow .beta. against the spring 11 via the dash rod 15 and the arm 4a. This displacement stops when the spring force of the spring 11 balances the fluid control pressure in the chamber 17. According to this displacement, the eccentricity A-ξ decreases. Therefore, the pump capacity becomes smaller to compensate for the excess. If the pump capacity is insufficient in this state, the fluid control pressure in the chamber 17 will decrease to compensate for the shortage, and the cam ring 4 will be moved by the spring force of the spring 11 accordingly. Return V in the direction of arrow α. At this time, the eccentricity increases by ξ, and the pump capacity compensates for the shortage.1. The rice will grow to a suitable value.

The capacity control device 1 can maintain the capacity of the pump 2 at an appropriate value at all times through the above-described effects.

While the capacity control device 1 is in operation, the fluid in the tube 17 drips into the drain chamber 18 from the piston communication hole 14a in small increments that do not affect the control pressure. This fluid is in chamber 1
8 through the gap 22 gold to the sliding part between the hole 3a and the bushing rod 15. The remaining fluid is removed from the chamber 18 through the drain passage 20. Thus, the above-mentioned IYi'l bushing rod 15 slides smoothly within the hole 3a, accurately transmits the movement of the piston 14 to the cam ring Φ, and accurately performs the above-mentioned displacement control.

Effects of the Invention Thus, the displacement control device for the variable displacement pump of the present invention has a configuration in which the displacement control piston 14 is provided with the small communication hole 14a, for example as described above, so that the fluid leaking from the communication hole 14a is : The space between the υ operating rod 15 and the hole 3a of the bong housing 3 into which the rod slidably penetrates can be constantly lubricated, and the operating rod 15 can be prevented from seizing and sticking.

Therefore, the actuating rod 15 always strokes smoothly and the capacity ii! I control can be performed accurately.

In addition, since the actuating rod 15 is slidably inserted into the hole 3a without play, the actuating rod 15 is reliably guided by the hole 8a and does not tilt, and the seal 21 is not locally lifted and the piston There is no need to stick 14.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal sectional sides of a rotor single vane type variable capacity bong equipped with a capacity control device that suffers from the problems to be solved by the present invention. FIG. 4 is a partial cross-sectional view for explaining the occurrence of a malfunction in the device. 1... Capacity control device of the present invention 2... Rotary vane type variable capacity bomb 3... Bump housing 3a... Operating rod inserter L4...
・Cam ring (capacity changing element) 5... Pivot pin 6... Rotor 7... Pump drive shaft 8... Vane 9... Pore 7
Chamber 10... Vane ring 11... Put it back 13
... Cylinder 14 ... Piston 1Φa ... Communication hole 15 ... Bush rod (operating rod) 17 ... Pressure chamber 18 ... Drain chamber 19 ... Fluid control pressure supply passage 2 (] ... Drain Passage 21...Piston seal 22
... Gap 23 ... Suction month Eid 24 ... Discharge boat.

Claims (1)

[Claims] 1. An actuating rod that engages with the capacity changing element of the variable displacement I4 pump is slidably inserted into the bong housing.
In a displacement control device for a variable displacement pump, in which the pump displacement can be controlled by displacing the element through the actuation rod by a piston responsive to fluid control pressure, a small communication hole that does not affect the fluid control pressure is provided. Front N [provided on 2 pistons. A displacement control device for a variable displacement pump, characterized in that the fluid leaking from the communication hole is configured to cause a sliding portion between the operating rod and the pump nozzle to deteriorate.