JPS6252155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vane pump motor used as a vacuum pump mounted on an automobile.

In general, it is always desirable to reduce power loss in machines that require power, but this is especially important for mechanical devices such as vacuum pumps installed in automobiles from the standpoint of reducing fuel consumption and weight. It has become a serious problem.

Conventionally, the heat generated by the rotating and sliding movement of the vanes of vane pumps and motors, including vacuum pumps, has been large.Especially when these vane pumps and motors are mounted on automobiles, engine oil is commonly used as the lubricating oil that lubricates the rotating and sliding movement. If the heat generated by the sliding is too large, it becomes necessary to replace the engine oil cooler with the one normally used and install a cooler with a larger cooling capacity.

However, this is due to manufacturing costs, space usage,
This is undesirable from the standpoint of weight reduction and fuel consumption reduction.

An object of the present invention is to provide a vane pump motor in which the amount of heat generated in the vane as described above is reduced.

To explain the present invention based on an embodiment, FIG. 1 shows a side sectional view of a vane pump motor as an embodiment of the present invention, and FIGS. vane 3
FIG.

In FIG. 1, a cam surface 1a cut into a housing 1 has a circular shape with a radius R from the center O, and a radius r from the center _O1 which is eccentric by an eccentric amount D from the center O.
Grooves 2a are cut in the rotor in the radial direction, and a vane 3 is inserted into each groove 2a to enable sliding movement in the radial direction, and the eccentricity D is R-r
There is a relationship between the tip 3b of the vane 3 and the cam surface 1.
Each sliding surface, such as the rotational sliding movement between
The rotor 2 is driven in the direction of an arrow 5 by an engine of an automobile (not shown).

To explain the operation in the above configuration, when the rotor 2 is driven by the engine in the direction of the arrow 5, each vane 3 is moved by the cam surface 1a due to centrifugal force.
While applying a pressing force to the cam surface 1a by rotation in the direction of the arrow 5, the groove 2a repeatedly slides in the radial direction within the groove 2a.
The displacement chambers 4, 4 located on the lower side of FIG. 1 undergo an expansion stroke and suck air from the suction hole 4b, and conversely, the displacement chambers 4, 4 located on the upper side of FIG. is discharged into the discharge hole 4a, and in this pumping action, the tip 3b in the vane and the cam surface 1
a, or between the vane 3 and the groove 2a, engine oil is jetted out in the form of a mist from a jet hole (not shown) to lubricate the mist, and the lubricating oil after lubrication is is cooled in a cooling circuit in engine oil.

In the above-mentioned operation, the rotational sliding movement between the tip 3b of the vane 3 and the cam surface 1a will now be considered.

The thickness t of the vane 3 in the direction of rotation (direction of arrow 5) is normally about 4 to 8 millimeters, and this is pressed against the cam surface 1a with centrifugal force as it rotates at a high speed of several thousand revolutions. Therefore, the curvature of the tip 3b should be as close as possible to the curvature of the cam surface 1a, and the entire width t of the vane 3 can be effectively used to bring it into contact with the cam surface 1a, thereby reducing the surface pressure on the contact surface. It can be used by lowering the
This reduces heat generation in the chip 3b.

However, as is clear from the illustration in FIG. 1, the vane 3 has a different inclination angle with respect to the tangent to the cam surface 1a as its rotation angle changes. It cannot be made the same as the curvature.

For this reason, the tip 3b is attached to the cam surface 1a.
When the shape is designed with a maximum possible radius of curvature α that is smaller than the radius of curvature of
This means that the surface pressure can be minimized.

The maximum possible value of the radius of curvature α will be discussed below.

As mentioned above, in order for the vane 3 to slide in contact with the cam surface 1a by effectively utilizing the entire width t, the tip must be placed in the state where the vane 3 is most inclined with respect to the tangent to the cam surface 1a. The end of 3b is the cam surface 1
It must be in the shape of an arc that smoothly touches a.

As shown in FIG. 1, the state where the vane 3 is most inclined with respect to the tangent to the cam surface 1a is from the position where the vane 3 is most extended from the groove 2a.
This occurs at a position rotated by 90 degrees, and this also means that even if the vane 3 is tilted within the groove 2a, taking into account the gap between the vane 3 and the groove 2a, the rotation of the 90 degrees within the error range It can be seen that in the rotated position, the vane 3 is most inclined with respect to the tangent to the cam surface 1a.

FIG. 2 is an enlarged view of the position where the vane 3 is rotated by 90 degrees, as described above.
The inclination in the groove 2a of the left displacement chamber 4
The figure shows a case in which the curve is tilted in the direction of decreasing .

On the other hand, during operation of this vane pump motor, the slope of the vane 3 with respect to the groove 2a may be opposite to that shown in FIG. 2, and this is shown in FIG.

Figure 3 shows that when compared with the case in Figure 2,
It is clearly seen that the inclination with respect to the tangent to the cam surface 1a is steeper than in the case of FIG. 2.
Therefore, the arcuate shape 3c of the tip 3b can be determined by considering the state in which it contacts the cam surface 1a and the end b of the vane effectively and smoothly contacts the cam surface 1a in the state shown in FIG. .

Therefore, the center of the arc shape 3c is b of the cam surface 1a.
Since the center exists on the normal line drawn from the point, the center exists at the intersection a of the center line 3a of the vane having the center line and the normal line, and its radius is α
becomes.

Here, the radius α may be determined by drawing as described above, but in order to improve the accuracy of the calculation, a formula for calculating α will be derived next.

In FIG. 3, the inclined center line 3a of the vane 3
The intersection point d between the centerline 2b of the groove 2a and the center line 2b of the groove 2a is the middle of the guiding length h of the vane 3 guided in the groove 2a, so the distance A between d and _o1 is A≒r-(h/ 2) (1), triangle efg and triangle d o ₁ o ₂ are similar shapes, and is approximately the difference between the width of groove 2a and the width of vane 3, that is, the total width of vane 3 with respect to groove 2a. It is equal to the gap s. Therefore, A:B=h:s or B=s×A/h (2).

Therefore, since D=R−r E=B+D or E=(R-r)+B (3) becomes.

Also, triangle abc and triangle a・o・o ₂ are approximately similar, and ≒t/2, so:
=:E or α:t/2=(R-α):E (4).

Therefore, from equations (1), (2), (3) and (4), However, in reality, considering the machining accuracy of the radius α and the machining error of the vane gap s, the right side of equation (5) is
It is desirable to multiply by a constant C between 1.0 and 0.8 and use it on the safe side.

This also means that by making the radius α somewhat smaller, including the processing error mentioned above, the vane 3 is inclined as shown in FIG. In this case, the slight gap between the cam surface 1a and the tip 3b at point b serves as an introduction section for lubricating oil and lubricates the tip 3b well.

FIG. 4 shows two types of vacuum pumps 11 and 21.
Calorific value ratio of the entire vacuum pump when conventional vanes are installed (ratio to maximum calorific value)
12 and 22 indicate the calorific value ratio q when the vane 3 according to the present invention is attached to the vacuum pumps 11 and 21, respectively.

In other words, it is an improvement of 12 compared to 11,
This is an improvement of 22 compared to 21. As a result, from FIG. 4, it can be seen that the vane 3 of the present invention improves the heat generation amount of the entire vacuum pump by about 20% compared to that using the conventional vane.

Note that α in the conventional vane is 6 mm, and the radius α of the vane of the present invention is the result of multiplying equation (5) by c=0.8.

Furthermore, although the above embodiment has been explained by taking a vacuum pump used in an automobile as an example, it will be easily understood that the structure shown in FIG. 1 can be used as it is as a normal pump or motor.

As is clear from the above explanation, the vane pump motor according to the present invention has the vane tip 3b.
By using the entire width t of the vane tip in effective contact with the cam surface 1a, it is possible to significantly reduce the amount of heat generated in the vane tip, thereby increasing the operating efficiency. , it became possible to reduce the power used.

In particular, when the vane pump motor of the present invention is installed in an automobile and conventional engine oil is used for lubrication, the cooler for the engine oil can be used without making it particularly large. This is excellent in terms of room space utilization, as well as in terms of the weight and manufacturing cost of the cooler, and the reduction in weight contributes to reducing the fuel consumption of automobiles.

[Brief explanation of the drawing]

FIG. 1 shows a vane pump motor as an embodiment of the present invention in a side sectional view, and FIGS. 2 and 3 each show an enlarged view of the vicinity of the vane 3 in FIG. 1 in side sectional views. FIG. 4 shows the characteristics of the heat generation ratio q when a conventional vacuum pump and a vane pump/motor according to the present invention are used as a vacuum pump. The symbols used in the examples are as follows. 1: Housing, 1a: Cam surface, 2: Rotor,
2a: Groove, 2b: Center line, 3: Vane, 3a: Center line, 3b: Chip, 3c: Arc shape, 4: Displacement chamber, 5: Arrow, o and o ₁ : Center, a, b,
c, e, f, g and o ₂ : point, d: intersection, R, r
and α: radius, h: guide length, s: total clearance of vane 3 with respect to groove 2a, q: ratio of generated heat, D:
Eccentricity (R-r), T: elapsed time (minutes).

Claims (1)

[Claims] 1. Vanes are inserted into grooves cut in the radial direction of the rotor so as to be able to slide in the radial direction, and the tips of the vanes rotate and slide while being in contact with each other. The shape of the cam surface is circular with a radius R, and the amount of eccentricity D of the rotor eccentric from the center of the R on the cam surface in the radial direction is equal to the outer diameter of the rotor in the radial direction. In the above configuration, where the radius is r, there is a relationship of D=R−r, where t: thickness of the vane in the rotational direction, h: 90° from the rotational position where the vane extends most in the radial direction. The length of the vane guided in the groove at the angle of rotation, s: The value obtained by subtracting t from the width of the groove in the rotation direction (total gap length between the vane and the groove), α: Vane The radius of curvature of the chip is convex in the radial direction in the rotation direction plane and has a center of curvature on the center line of the thickness of the vane, c: a constant of 0.8 to 1.0. A vane pump motor characterized in that the vane has a tip shape having the following relationship. 2. The vane pump motor according to claim 1, wherein the rotor is driven by an automobile engine. 3. The vane pump/motor according to claim 2, wherein the lubricating oil that lubricates the sliding movement of the vane shares the lubricating oil that lubricates the rotating and sliding parts of the engine.