JPS62271981A - vane pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a vane pump, and more particularly, to a power steering vane pump for reducing the steering force of the power steering of an automobile.

(Prior Art) As a conventional vane pump, one shown in FIG. 5 is known. Reference numeral 1 denotes a cam ring housed in a housing 2, and the cam ring 1 has a cam surface 3 consisting of a large circular portion 3a and a small circular portion 3b. A rotor 5 to which vanes 4 are removably attached is housed in the cam ring 1, and a pair of discharge chambers 6.
7 is defined. The volumes of the pair of discharge chambers 6.7 are equal because the radii of the large circular portion 3a and the small circular portion 3b are constant.

Further, both ends of the cam ring 1 in the axial direction are closed by a front plate (not shown) and a rear plate 8, respectively. An introduction channel (not shown) for guiding hydraulic oil is formed in the housing 2, and this introduction channel is connected to a carrier cover 8.
are formed continuously. The introduction passage 9 formed in the rear cover 8 is formed substantially perpendicular to the axis of the rotor 5, and branches into two parts in the middle to introduce hydraulic oil into each of the discharge chambers 6.7. In the discharge chamber 6.7, when the rotor 5 is rotated in the direction of arrow (A), hydraulic oil is sequentially introduced into the discharge chamber 7 from the introduction channel 9 by the pump action of the suction chamber 10.11 defined by the vane 4. A forward suction port 12 for sucking air into the discharge chamber 6 in the opposite direction and a reverse suction port 13 for sucking air into the discharge chamber 6 in the opposite direction are open.

In this vane pump, a suction stroke and a discharge stroke are performed in one rotation of the rotor 5. That is, in the pair of discharge chambers 6.7, hydraulic oil is sucked in from the forward suction port 12 and the reverse suction port 13 by the pumping action of the suction chamber 10.11 defined by the vane 4, and the hydraulic oil is sucked into the respective discharge ports (Fig. (not shown).

(Problems to be solved by the invention) However, with such a vane pump,
The hydraulic oil sucked by the pump action of the suction chamber 10 in the discharge chamber 7 on the forward suction port side is sucked in the forward direction into the discharge chamber 7 from the introduction flow path 9 through the forward suction port 12. Due to the inertia of the hydraulic fluid, there is little flow resistance and the fluid is sucked in smoothly. On the other hand, the discharge chamber 6 on the reverse suction port side
The hydraulic oil sucked by the pumping action of the suction chamber 11 in is sucked in the reverse direction from the introduction flow path 9 through the reverse direction suction port 13 into the discharge chamber 6, so the flow path resistance is large.
It is not inhaled smoothly. Therefore, the amount of hydraulic oil sucked into the discharge chamber 6 on the reverse side of the suction port is smaller than the amount of hydraulic oil sucked into the discharge chamber 7 on the forward side of the suction port. For this reason, the rotor 5 is rotated at a high speed of 7,500 r, p, m or more (8,000 to 9.00 or, p, m).

), the suction chamber 1 in the reverse direction suction port side discharge chamber 6
Cavitation occurred in 1. That is, air bubbles are generated in the hydraulic oil in the suction chamber 11, and when the air bubbles disappear, vibrations and noise are generated in the vane pump, and the vanes 4, the inner peripheral wall of the cam surface 3, the outer peripheral wall of the rotor 5, etc. are eroded. There was a problem that

(Means for Solving the Problems) Therefore, in order to solve these problems, the present invention has been developed to provide a cam ring having a cam surface consisting of a large circular part and a small circular part, and a rotor housed in this cam ring. a pair of discharge chambers defined between the cam ring and the rotor; and an introduction flow path that is arranged approximately perpendicular to the axial direction of the rotor and branches into two from the middle to introduce working fluid into each of the discharge chambers. , a forward suction port in which the working fluid is sucked forward into one discharge chamber through the introduction channel as the rotor rotates, and a reverse suction port in which the working fluid is sucked in the reverse direction into the other discharge chamber through the introduction channel. In the vane pump, the length obtained by subtracting the forward suction port side radius of the small circular portion from the forward suction port side radius of the large circular portion is smaller than the reverse suction port side radius of the large circular portion. The length of the circular portion is larger than the radius of the circular portion on the inlet side in the opposite direction.

(Function) When the rotor is rotated, the hydraulic oil sucked by the pump action of the suction chamber in the discharge chamber on the forward suction side is sucked forward from the introduction flow path into the discharge chamber through the forward suction port. Therefore, due to the force of inertia of the hydraulic fluid, there is little resistance in the flow path and the fluid is sucked in smoothly. Since the gas is sucked into the discharge chamber in the opposite direction through the directional suction port, the flow path resistance is large and the suction is not smooth. However, in the present invention, the amount of hydraulic oil sucked by the pumping action of the suction chamber in the discharge chamber on the reverse suction side is different from the amount of hydraulic oil sucked in by the pumping action of the suction chamber in the discharge chamber on the forward suction side. Since the cam ring is formed so that the amount of suction is less than It can be prevented.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. Figures 1 to 4 show a first vane pump according to the present invention.
It is a figure showing an example.

In FIG. 1, a housing 21 houses a cam ring 22, and the housing 21 rotatably supports a drive shaft 24 having a pulley 23 attached to one end thereof via a bearing 25. A rotor 26 is rotatably housed in the cam ring 22, and both ends of the cam ring 22 are connected to a front plate 27 and a rear plate 28.
is closed by. The cam ring 22 and the front plate 27 are housed within the housing 21, but the rear plate 28 seals the housing 21 from the outside as a rear cover. The rotor 26 is spline-fitted to the other end of the drive shaft 24. An introduction channel 29 for introducing hydraulic oil is formed in the upper part of the housing 21,
The introduction passage 29 communicates with an introduction passage 29 formed in a rear plate 28 that seals the housing 21. As shown in FIG. 2, the introduction channel 29 is formed from the upper part thereof downward and substantially perpendicular to the axial direction of the rotor 26, and branches into two parts in the middle. It is open on the side. On the other hand, the cam ring 22 has a large circular portion 31 and a small circular portion 32 as shown in FIG.
A cam surface 33 is formed, and a vane 34 is attached to the rotor 26 so as to be freely retractable. A pair of discharge chambers 36 and 37 are defined between the large circular portion 31 and the rotor 26, and when the rotor 26 rotates in the direction of arrow (B), the hydraulic oil flows forward from one side 29a of the introduction channel 29. Inflow discharge chamber 37
A forward suction port 38 is opened in the inlet, a reverse suction port 39 is opened in the discharge chamber 36 which flows in the reverse direction from the other side 29b of the introduction flow path 29, and a discharge Each outlet (not shown) is open. A large circular portion 31 defining a discharge chamber 36 into which a reverse suction port 39 opens.
The inner circumferential wall of is a discharge chamber 37 in which the forward direction side suction port 38 opens.
The rotor 26 is formed slightly closer to the outer circumferential wall surface of the rotor 26 than the inner circumferential wall of the large circular portion 31 defining the rotor 26 . That is, the cam ring 22 is formed so that the radius R on the forward suction port side of the large circular portion 31 and the radius R2 on the reverse suction port side are shorter than the radius R on the forward suction port side. Therefore, the volume of the discharge chamber 36 to which the reverse direction side inlet 39 opens is smaller than the volume of the discharge chamber 37 to which the forward direction side inlet 38 opens. As a result, the suction chamber 4 defined by the vane 34 in the discharge chamber 36
The amount of hydraulic oil sucked into the discharge chamber 37 is smaller than the amount of hydraulic oil sucked into the suction chamber 41 defined by the vane 34 in the discharge chamber 37 .

On the other hand, the radius of the small circular portion 32 remains constant.

Therefore, the length obtained by subtracting the forward suction port side radius of the small circular portion 32 from the forward suction port side radius R+ of the large circular portion 31 is the length obtained by subtracting the forward suction port side radius of the small circular portion 32 from the reverse suction side radius R2 of the small circular portion. It is larger than the length minus the radius on the intake port side.

Next, the effect will be explained.

The rotational driving force of the engine rotates the rotor 26 via the boot IJ-23 and the drive shaft 24.

When the rotor 26 rotates in the direction of arrow (B) in FIG.
9 into the discharge chamber 37,36.

This hydraulic fluid is discharged from the respective discharge ports by the pump action of the suction chambers 41, 40, and is sent to an actuator (not shown). At this time, the hydraulic oil sucked by the pumping action of the suction chamber 41 flows through one side 29 of the introduction channel 29.
Since the hydraulic oil is sucked in the forward direction from a to the discharge chamber 37 through the forward suction port 38, it is sucked in smoothly by the inertial force of the hydraulic oil, but the operation sucked by the pumping action of the suction chamber 40 is Oil is sucked into the discharge chamber 36 in the opposite direction from the other side 29b of the introduction flow path 29 through the reverse suction port 39, so that the oil is not sucked smoothly. That is, the amount of hydraulic oil sucked into the suction chamber 40 is smaller than the amount of hydraulic oil sucked into the suction chamber 41. Therefore, in the first embodiment, the cam ring 22 is formed so that the radius R on the forward suction port side and the radius R2 on the reverse suction port side of the large circular portion 31 are made shorter, so that the volume of the discharge chamber 36 is reduced. 3
It is smaller than the volume of 7. For this reason, the suction chamber 4
The amount of hydraulic oil sucked in by the pump action of the suction chamber 41 is smaller than the amount of hydraulic oil sucked by the pump action of the suction chamber 41. Therefore, the rotor 26 is rotated at a high speed of 7,500 r, p, m or more (8,0
00~9.00Or, p, m, ), the suction chamber 4
0 pump action is not strained, and cavitation does not occur in this suction chamber 40. Therefore, generation of vibration and noise due to cavitation is prevented, and the base 73
4. The inner circumferential wall of the large circular portion 31 and the outer circumferential wall of the rotor 26 are not eroded.

FIG. 4 shows a second embodiment of the vane pump according to the present invention.

First, the configuration will be explained, and the same components as those in the first embodiment will be given the same reference numerals and the explanation will be omitted. In Figure 4,
When the rotor 26 rotates in the direction of arrow (B), the discharge chamber 37 into which hydraulic oil flows in the forward direction from one side 29a of the introduction channel 29 formed by branching into two, has a forward inlet port 38 and a discharge port. 51 is open, and the other 29b of the introduction channel 29
A reverse suction port 39 is provided in the discharge chamber 36 that flows in the opposite direction from the
and discharge port 52 are open. The inner circumferential wall of the small circular portion 32 on the reverse suction port 39 side is the same as the small circular portion 32 on the forward suction port 38 side.
There is a slight gap (1
) are formed apart from each other. That is, the small circular portion 32
The cam ring 53 is formed so that the forward direction suction port side radius r and the reverse direction suction port side radius r2 are longer.

On the other hand, the radius of the large circular portion 31 remains constant.

Therefore, the length obtained by subtracting the forward suction port side radius (rl) of the small circular portion 32 from the forward suction port side radius of the large circular portion 31 is
The length obtained by subtracting the radius (r2) of the small circular portion on the reverse suction port side from the radius of the large circular portion on the suction port side in the reverse direction is also larger.

Next, the effect will be explained.

The hydraulic oil sucked by the pumping action of the suction chamber 41 in the forward suction side discharge chamber 37 is sucked forward into the discharge chamber 37 from one side 29a of the introduction flow path 29 through the forward suction port 38. Therefore, the inertial force of the hydraulic fluid allows it to be sucked in smoothly. On the other hand, the discharge chamber 3 on the reverse suction port side
The hydraulic oil sucked by the pumping action of the suction chamber 40 at step 6 is sucked in the opposite direction from the other side 29b of the introduction channel 29 through the reverse suction port 39 into the discharge chamber 36, so that it is not sucked smoothly. That is, the amount of hydraulic fluid sucked into the discharge chamber 36 by the suction chamber 40 defined by the vane 34 is smaller than the amount of hydraulic fluid sucked into the discharge chamber 37 by the suction chamber 41 defined by the vane 34 . Therefore, the cam ring 53 has a radius r on the forward inlet side of the small circular portion 32 and a radius r2 on the inlet side in the reverse direction.
Since the pump action of the suction chamber 41 causes the hydraulic oil to be sucked in from the forward suction port 38 and discharged from the discharge port 51, the hydraulic oil is drawn into the small circular portion 32 on the reverse suction port 39 side. The liquid is also fed into the discharge chamber 36 on the suction port side in the opposite direction through the gap C1> between the inner circumferential wall of the rotor 26 and the outer circumferential wall surface of the rotor 26. Therefore, depending on the pumping action of the suction chamber 40, only a small amount of hydraulic oil can be sucked from the reverse suction port 39.

Therefore, in the discharge chamber 36 on the reverse suction side, a small amount of hydraulic fluid is sucked in from the reverse suction port 39 and a large amount is discharged from the discharge port 52, whereas in the discharge chamber 37 on the forward suction side, The relationship is such that a large amount of hydraulic oil is sucked in from the forward suction port 38 and a small amount is discharged from the discharge port 51. Therefore, the rotor 26 is 7.50 Or, p.

High speed rotation at m1 or more (8,000~9.0OOr, p,
m, ), the pumping action of the suction chamber 40 in the discharge chamber 36 where the opposite direction side port 39 opens is not strained,
Cavitation does not occur in this suction chamber 40.

It should be noted that one revolution of the rotor 26 causes a discharge from the discharge port 52! Ij
Since a large amount of oil is discharged and at the same time a small amount is discharged from the discharge port 51, there is an imbalance, but since these hydraulic fluids are immediately merged after coming out from the discharge ports 51 and 52,
There is no problem.

On the other hand, in the first embodiment, the cam ring is formed so that the reverse suction side radius R2 is shorter than the forward suction side radius R2 in the large circular part, and in the second example, the forward suction side radius R2 in the small circular part is formed. The cam ring is formed so that the reverse suction side radius r7 is longer than the mouth side radius r+, but in total, the reverse suction side radii R and L are longer than the forward suction side radius Rt in the large circular part. The cam ring may be shortened, and the cam ring may be formed so that the radius r2 on the reverse suction port side is longer than the radius r1 on the forward suction port side in the small circular portion.

Even in this case, as in the above embodiment, the pumping action of the suction chamber in the discharge chamber where the reverse suction port opens is not strained, and cavitation does not occur in this suction chamber.

(Effects of the Invention) As explained above, in this invention, the length obtained by subtracting the radius of the forward suction port of the small circular portion from the radius of the forward suction port of the large circular portion is the radius of the forward suction port of the large circular portion. Since the length is larger than the side radius minus the radius of the small circle on the reverse suction side, the rotor can be rotated at high speeds (8,000 ~
9,0OOr, p, m, ), the pumping action of the suction chamber in the discharge chamber where the reverse suction port opens is not strained, and cavitation does not occur in this suction chamber. Therefore, generation of vibration and noise in this vane pump due to cavitation is prevented, and the vanes, the inner circumferential wall of the large circular portion, and the outer circumferential wall of the rotor are not eroded.

[Brief explanation of the drawing]

1 to 3 are diagrams showing a first embodiment of the vane pump according to the present invention, and FIG. 1 is an overall sectional view of the vane pump, and FIG.
The figure is a cross-sectional view taken along the line ■--■ in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line III--III in FIG. FIG. 4 shows a second embodiment of the vane pump according to the present invention, and is a sectional view showing the main part in which the rotor is housed in the cam ring. FIG. 5 is a sectional view showing the main parts of a conventional vane pump. 22...Cam ring, 26...Rotor, 29...Introduction channel, 31...Large circular portion, 32...Small circular portion , 33... Cam surface, 36... Discharge chamber, 37... Discharge chamber, 38... Forward direction suction port, 39...... Reverse intake. Figure 1 22, sword A1 Luk. 26: Rotor 29 humiliation flow 78 Figure 4 Figure 5

Claims (3)

[Claims] (1) A cam ring having a cam surface consisting of a large circular part and a small circular part, a rotor housed in this cam ring, a pair of discharge chambers defined between the cam ring and the rotor, and an axial direction of the rotor. An introduction channel is arranged approximately perpendicular to the main body, and branches into two parts in the middle to introduce working fluid into each of the discharge chambers.The rotation of the rotor causes the working fluid to be sucked in the forward direction into one of the discharge chambers through the introduction channel. In a vane pump comprising a forward suction port and a reverse suction port through which working fluid is sucked in the opposite direction into the other discharge chamber through an introduction flow path, a small circle is formed from a radius on the forward suction port side of the large circular portion. A vane pump characterized in that the length obtained by subtracting the forward suction port side radius of the large circular portion is greater than the length obtained by subtracting the reverse suction port side radius of the small circular portion from the reverse suction port radius of the large circular portion. . (2) The radius of the small circular portion is constant, and the radius of the large circular portion on the reverse suction port side is shorter than the radius of the large circular portion on the forward suction port side. vane pump. (3) The vane pump according to claim 1, characterized in that the radius of the large circular portion is constant, and the radius of the small circular portion on the reverse suction side is longer than the radius on the forward suction side of the small circular portion. .