JPS6321839B2 - - 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, a large amount of heat is generated due to the rotating and sliding movement of the vanes of vane pumps and motors, including vacuum pumps.Especially when these vane pumps and motors are mounted on automobiles, engine oil is often used as the lubricant for 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 extending from center O to R1.
The rotor 2, which is eccentrically supported in the housing 1, has an outer diameter R2, and is at a position parallel to an imaginary plane formed in the radial direction of the rotor 2 and in the direction of the rotational axis of the rotor 2, by an offset amount eo. A groove 2a is cut around this position, and a vane 3 that enables sliding movement in the same radial direction as the imaginary plane is inserted into the groove 2a. The shape of is located at point k in the plane shown in Figure 1.
It forms an arc with radius r centered at .

The displacement chambers 4, 4 formed by the cam surface 1a, the rotor 2, and the vanes 3 repeatedly expand or compress as the rotor 2 rotates, and as a result, a pump action or a motor action is performed. It is configured to do this.

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 chamber 4 located on the lower side of FIG. 1 undergoes an expansion stroke and sucks in air from a suction hole (not shown), and conversely, the displacement chamber 4 located on the upper side of FIG. 1 absorbs the sucked air. Discharge to a discharge hole not shown,
In the pumping action, the tip 3 in the vane
a and the cam surface 1a, or between the vane 3 and the groove 2.
For sliding movement between a and a, engine oil is jetted in a mist form from a jet hole (not shown) to lubricate the mist, and the lubricating oil that has been lubricated is cooled in a cooling circuit for the engine oil. Ru.

In the above-mentioned action, the rotational sliding between the tip 3a 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 of the vane 3 (direction of arrow 5) is normally about 4 to 8 mm, and the centrifugal force of the vane 3 rotating at a high speed of several thousand revolutions is applied to the cam surface 1a. Due to the pressing, the curvature of the tip 3a is as close to the cam surface 1 as possible.
The heat generation in the chip 3a can be reduced by approaching the curvature of the tip 3a and making effective use of the entire width t of the vane 3, bringing it into contact with the cam surface 1a, and lowering the surface pressure on the contact surface. It will be made smaller.

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

For this reason, the tip 3a is attached to the cam surface 1a.
When the shape is designed with the largest possible radius of curvature r in a range 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 r will be discussed below.

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

Here, the rotation angle α of the rotor 2 at which the vane 3 is most inclined with respect to the normal to the cam surface 1a will be considered.

FIG. 5 shows the rotation angle α of the rotor 2 in FIG.
This is an enlarged view of the vicinity of the vane 3 on the upper side of FIG. 1 when the vane 3 is at an arbitrary rotation angle.

In Fig. 5, or: center of rotation of rotor 2, point k: center of radius of curvature of tip 3a in vane 3, k to a: auxiliary line provided parallel to vane groove 2a, o to k: direction of cam surface 1a line (i.e. point o is the center of curvature of the cam surface 1a), d: reference line parallel to the vane grooves 2a and k to a and indicating the rotation angle α of the rotor 2 passing through the rotation center or of the rotor 2, E : Eccentricity of the rotor 2 with respect to the center o of the cam surface 1a, B: Distance between the reference line d and the auxiliary lines a to k.

Auxiliary lines a to k from point o on the eccentric direction reference line 2b
And if we drop a perpendicular line on the reference line d and let the dropped points be points b and c, then o~c=E×sinα (A1), and o~b=(o~c)−B (A2) Therefore, , (A1) and (A2), ob~b=(E×sinα)−B (A3).

Also, let the length of o to k be A, and regarding the inclination angle θ of the vane 3 with respect to the normal line o to k of the cam surface 1a, sinθ=(o to b)/A (A4), and the formula (A4) is written as (A4). Substituting the formula A3), we get sinθ= (1/A) ((E×sinα)-B)) (A5).

The result of equation (A5) is shown graphically in Figure 6. Note that A, B, and E in the above formula (A5) are constant values determined by design.

As is clear from FIG. 6, during one rotation of the rotor 2 in FIG. 1 or FIG. 6, that is, at 0<α<360 degrees, the absolute value of sin θ is α=
It is maximum at rotational positions of 90 degrees and α = 270 degrees.

In this case, considering the maximum value of θ, we get
By design, the position of point b is always located inside the circle 3b, which is the movement locus of point k.

This means that there is a relationship of o~b<o~k or o~b<A, so the relationship of sinθ=(o~b)/A<A/A=1 or sinθ<1 (A6) It is in. This means that θ<90 degrees (A7), and this means that 0
When <θ<90 degrees, as θ increases, sin θ also increases, so conversely, this means that
Under the condition of equation (A7), when sin θ becomes maximum, it means that θ becomes maximum.

This means that 0<α<
At 180 degrees (above the eccentric direction reference line 2b),
At the position of α = 90 degrees where sin θ is maximum, θ is maximum, and at 180 degrees < α < 360 degrees (below the eccentric direction reference line 2b), θ is maximum at α = 270 degrees. It is shown that.

That is, the vane 3 is aligned with the normal ok of the cam surface 1a.
The position where the vane 3 is most inclined to the eccentric direction reference line 2b is the position where the vane 3 is perpendicular to the eccentric direction reference line 2b.

FIG. 2 is an enlarged view of the state in which the vane 3 is in the vertical state and the short sliding surface 2c side of the groove 2a of the rotor is located on the side closer to the center O, as described above. Yes, groove 2a of vane 3
A case is shown in which the inclination in the left side is inclined in a direction to enlarge the displacement chamber 4 on the left side.

On the other hand, depending on the operation of this vane pump motor, the slope of the vane 3 with respect to the groove 2a may be in the opposite direction to that shown in FIG. 2. Tip 3a for tilt
This corresponds to a case where the operation is easy because the direction increases the radius r.

Therefore, the shape of the tip 3a can be determined by determining the radius r for the direction of inclination of the vane 3 in the severe condition shown in FIG.

In addition, the term "short sliding surface 2c" means that the length of the vane 3 guided in the groove 2a is short on the 2c side of the groove 2a and on the 2d side, as is clear from the configuration of FIG. Since it has a long configuration, the short side is named the "short sliding surface", and the long side 2d is named the "long sliding surface".

In the state shown in FIG. 2, the vane 3 is inclined with respect to the normal line o to j to the cam surface 1a, and
The shape of the chip 3a at the corner point j in contact with a is
In order to achieve the above-mentioned ideal, it is necessary to form a circular arc that is in contact with the cam surface 1a, and for this purpose, the center k of the circular arc must lie on the normal lines o to j.

The location of center k will be discussed below.

In FIG. 2, normal lines o to j, eccentric direction reference line 2b, and side extension lines j to f of the vane 3
Focusing on the triangle formed by the triangle jfo, if straight lines h to k passing through the center k and parallel to the eccentric direction reference line 2b are provided in the triangle jfo, the triangle jof and the triangle jkh become similar. Therefore, jk/jo=hk/of (1) where jk=r, jo=R1, hk=t2 and of=x1
Therefore, rearranging equation (1) results in r=R1×t2/x1 (2).

Furthermore, since x1 in equation (2) includes an unknown quantity c3 as is clear from FIG. 1, c3 will be found below.

Triangle abc and triangle cde are similar, and c~
The length b is approximately equal to the difference in length between the groove 2a and the vane 3 in the rotor rotation direction.
It can be regarded as t=c1. Therefore, d1/c1=(to-c1)/c2 or c2=(to-c1)×c1/d1 (3) Also, since triangle abc and triangle egf are similar, d1/c1=(d2+c2)/ c3 Therefore, c3=(d2+c2)×c1/d1 (4), and substituting equation (3) into equation (4), c3=(c1/d1) ² ×(to−c1)+(c1/d1)× d2 (5).

Here, since x1=c3+xo, by substituting equation (5) into this, we obtain x1=(c1/d1) ² ×(to−c1)+((c1/d1)×d2)+xo (6).

When formula (6) is substituted into formula (2) above, since formula (2) includes two unknowns, r and t2, a new relational expression between r and t2 is determined below.

The radius of curvature at the tip 3a of the vane is set to a constant value r, and since the tip 3a always slides and rotates in contact with the cam surface 1a, the center of curvature k
will move on a circumferential circle 3b centered on the center o, as shown in FIG.

When the vane 3 is perpendicular to the eccentric direction reference line 2b, and the short sliding surface 2c in the vane groove 2a is located on the far side from the center o (position of the vane 3 on the lower side of FIG. 1) , since the vane 3 is in the other state where it is most inclined with respect to the cam surface 1a, the corner point m of the tip 3a must be in contact with the cam surface 1a at this time, and the curvature of the side of the tip 3a at the contacting portion is as follows. , must be radius r as described above. Moreover, at this time as well, the center k of the radius r exists on the circumferential circle 3b.

FIG. 3 shows an enlarged view of the vane 3 located on the lower side in FIG. 1, and as is clear from FIG. 3, corner point m is also The center k of the radius r is the cam surface 1a
It must be located at the intersection of the normal line mo from the corner point m and the circumferential circle 3b.

Here, n is parallel to the eccentric direction reference line 2b.
When ~k is provided, triangle mso and triangle mnk become similar, as in FIG.

Therefore, y1/om=t3/km (7) where om=R1 and km=r, (7)
Rearranging the equation, it becomes r=R1×t3/y1 (8).

Here, y1=yo−c4 (9), and since c4 is an unknown number, the following unknown number c4 is found from Figure 3. Since triangle auv and triangle aqs are similar, c1/d3=c4/(d3+d4) or c4 = c1×(d3+d4)/d3 (10). Therefore, from equations (9) and (10), we obtain y1=yo−(c1/d3)×(d3+d4) (11).

Also, consider t3 in equation (8).

Since the length of the normal ki extending from the center k to the side surface of the vane 3 is assumed to be t2o as shown in Fig. 2, the length of kp extended from the normal ki to i is t-
Since triangle knp and triangle khi are similar, t2o/t2=(t-t2o)/t3 or t3=(t2/t2o)(t-t2o) (12), and it is clear from Fig. As such, t2≒t2o (13) Therefore, equation (12) can be written as t3≒t−t2o (14).

Therefore, from equations (8) and (14) we get r=R1×(t-t2o)/y1 (15), and from equations (2) and (13) we get r=R1×t2o/x1 (16) Finally, from equations (15) and (16), t2o=x1×t/(x1+y1) (17) and r=R1×t/(x1+y1) (18), and equations (17) and (18) Inside, x1 and y1 are
It can be obtained from equations (6) and (11).

From the above calculation results, the center k of the radius of curvature r at the tip 3a of the vane can be found from equations (17) and (18), and when actually designing the shape of the tip 3a, use equation (18). Using the value of the radius r obtained above, draw an arc centered on the corner point j on the chip 3a, and then draw the arc of the vane 3 on the side of the corner point j using the dimension t2o obtained from equation (17). A parallel line is provided from the side, and the intersection of the parallel line and the arc becomes the center k to be determined.

In the above explanation, for simplicity, equation (12) is approximated as in equation (13), but
Strictly speaking, t2 in equation (12) can also be expressed by t2o. This is because triangle kih and triangle abc are similar in Figure 2, so t2/t2o=√1 ² +1 ² /d1 or t2=t2o×√1 ² +1 ² /d1 (17), and Equation (17) By substituting t3 into equation (12), t3 in this case in equation (12) becomes an exact solution as a function of t2o. Further, the subsequent calculations may be performed in the same manner as the above-mentioned approximate calculation process.

However, just to be sure, I will discuss the error in the above approximate solution.

In other words, if we rearrange equation (17), we get t2=t2o×√(11) ² + 1 (18), and c1/
The average value of d1 is about 0.016.

Therefore, by substituting the practical c1/d1 into equation (18), we get t2=1.00013×t2O, and the above calculation of r and t2o using the above equations (17) and (18) is sufficient. It is.

Also, considering the machining accuracy and total assembly error of r and t2O, it is desirable to use the right side of equation (18) on the safe side by multiplying it by a constant C of 1.0 to 0.8.

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)
In the figure, 12 and 22 indicate the experimental values of 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 r in the conventional vane used in FIG. 4 above is 6 mm, and the vane of the present invention is
The radius r is the result of multiplying equation (5) by C=0.8.

Further, 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 description, the vane pump motor according to the present invention has a vane tip 3a.
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. 4 shows the characteristics of the heat generation ratio Q when a conventional vacuum pump and the vane pump motor of the present invention are used as a vacuum pump, and FIG. 5 shows the characteristics of the cam of the vane 3 in FIG. FIG. 6 is an explanatory diagram of the inclination angle of the vane 3 with respect to the surface 1a, and FIG. 6 is a graph showing the relationship between the rotation angle α of the rotor 2 and the inclination angle θ of the vane 3.
The symbols used in the examples are as follows. 1: Housing, 1a: Cam surface, 1b: Reference line, 2: Rotor, 2a: Groove, 2b: Eccentric direction reference line, 2c: Short sliding surface, 2d: Long sliding surface, 3: Vane, 3a: Chip , 3b: circumference, 3c: bottom,
4: Displacement chamber, 5: Arrow, R1: Radius of curvature of cam surface 1a, R2: Outer diameter (radius) of rotor 2, eo:
Offset amount of vane 3, r: radius of curvature of chip 3a, xo: dimension from reference line 1b to long sliding surface 2d, yo: dimension from reference line 1b to short sliding surface 2c, o and k: center, t: Thickness of the vane 3 in the rotational direction 5, to: Thickness of the vane groove 2a in the rotational direction 5, t2o: Length of a perpendicular line drawn from the center k to the side surface of the vane 3, a, b, c, d, e, f, g, h,
i, j, m, n, p, q, s, u and v: points,
d1 and d3: length guided in the groove 2a of the vane 3, d2 and d4: bottom 3 of the vane 3
Length from c to eccentric direction reference line 2b.

Claims (1)

[Claims] 1. A groove cut parallel to a drive shaft direction plane radially from the rotation center of the rotor at a distance of an offset amount eo has a groove that prevents sliding in the radial direction. The shape of the cam surface into which the vane can be inserted and which rotates and slides while being in contact with the tip of the vane is circular with a radius R1, and in the radial direction, the cam surface of the rotor The amount of eccentricity E that is eccentric from the center of R1 in is in the relationship E = R1 - R2, where R2 is the radius of the outer diameter of the rotor in the radial direction. In the above configuration, t: the vane Thickness in the rotational direction, d1: With respect to the eccentric direction reference line of the rotor,
When the groove is vertically located and the short sliding surface of the groove of the rotor is located on the side closer to the circular center of the cam surface, the length of the vane guided by the short sliding surface. , d2: the length from the bottom of the vane to the eccentric reference line when the vane is in the position showing the dimension d1, xo: the vane is in the position showing the dimension d1 where, the length from a reference line (vertical reference line 1b) perpendicular to the eccentric direction reference line and passing through the center of the circular shape to the long sliding surface in the vane groove, d3: the eccentric direction reference When the groove is perpendicular to the line and the short sliding surface is located on the side far from the center of the circular shape, the length that the vane is guided by the short sliding surface, d4: When the vane is in the position showing the dimension d3, the length from the bottom of the vane to the eccentric reference line, yo: When the vane is in the position showing the dimension d3, the length yo: the length from the vertical reference line to the short sliding surface; to: groove width of the vane groove in the rotational direction; c1: to-t; r: the groove convex in the radial direction on the rotational direction surface; Radius of curvature at the tip of the vane, t2o: Length from the side surface of the vane on the long sliding surface side to the center of curvature at r, c: Constant from 0.8 to 1.0, as r=c×R1×t /(x1+y1) t2o=x1×t/(x1+y1) However, x1=(c1/d1) ² (to-c1)+ (c1/d1)d2+xo y1=yo-(c1/d3)(d3+d4) A vane pump motor characterized in that the vane has a tip shape. 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.