JPS6252156B2 - - 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, the cam surface 1a cut into the housing 1 has a circular shape with a radius R ₁ from the center O, and the rotor 2 eccentrically supported in the housing 1 from the center O has an outer diameter R ₂ . A groove 2a is cut at a position parallel to an imaginary plane formed in the radial direction of the rotor 2 and in the rotational axis direction of the rotor 2, with the groove 2a as the center, and the offset amount eo is , if the groove width in the rotational direction of groove 2a is to, then R ₁
−R ₂ +(to/2), and a vane 3 is inserted into the groove 2a to enable sliding movement in the same radial direction as the virtual surface, and the tip in the vane 3 is inserted into the groove 2a. The shape of 3a is an arc of radius r centered on point k in the plane shown in FIG.

The displacement chambers 4, 4 are each formed by the cam surface 1a, the rotor 2, and the vane 2, and the displacement chambers 4, 4 repeatedly expand or compress as the rotor 2 rotates. As a result, it is configured to perform a pump action or a motor action.

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 provide lubrication, 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.

In order for the vane 3 to slide in contact with the cam surface 1a by effectively utilizing the full width in the rotational direction as described above, the vane 3 must be in the most inclined state with respect to the normal to the cam surface 1a, and At each position in the most upright position, the end of the tip 3a in the rotational direction must form an arc that smoothly contacts the cam surface 1a.

Here, the rotation angle α of the rotor 2 at which the vane 3 is tilted at both extremes as described above 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-b: auxiliary line provided parallel to vane groove 2a, o-k: direction of cam surface 1a line (i.e. point o is the center of curvature of the cam surface 1a), d: a reference line that is parallel to the vane grooves 2a and k to b and indicates the rotation angle α of the rotor 2 and passes through the rotation center or of the rotor 2, E : the amount of eccentricity of the rotor 2 with respect to the center o of the cam surface 1a, B: the distance between the reference line d and the auxiliary lines b to k, and the relationship B>E.

Pass through point o on the eccentric direction reference line 2b and drop a perpendicular line onto the auxiliary lines b to k and reference line d, and let the dropped points be points b and c, then o to c=E×sinα ( A1) and o~b=B-(o~c) (A2) Therefore, from equations (A1) and (A2), o~b=B-(E×sinα) (A3).

Also, let the length of o to k be A, and the inclination angle θ of the vane 3 with respect to the normal line o to k of the cam surface 1a has the relationship sinθ=(o to b)/A (A4), and (A4 ) By substituting the equation (A3) into the equation, sinθ=(1/A) {B−(E×sinα)} (A5).

The result of equation (A5) is shown graphically in Figure 6.

As is clear from FIG. 6, during one rotation of the rotor 2 in FIG. 1 or FIG. 6, that is, when 0<α<360 degrees, the minimum and maximum values of sin θ are α=90 degrees and α= It is maximum at the 270 degree rotation position.

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) , which means that θ<90 degrees (A7), and this means that 0
<θ<90 degrees, as θ increases, sinθ
Since there is a relationship in which the
This means that under the conditions of equation (A7), θ becomes the minimum when sin θ becomes the minimum, and θ becomes the maximum when the sin θ becomes the maximum.

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

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 relative to the normal line ok to the cam surface 1a occurs at α=270 degrees.

FIG. 2 is an enlarged view of the state in which the groove 2a is vertical and located on the side closer to the center O, as described above, and shows the inside of the groove 2a of the vane 3. A case is shown in which the inclination is in the direction of enlarging the displacement chamber 4 on the left side.

On the other hand, in this vane pump/motor, depending on the operation of the pump action or the motor action, the slope of the vane 3 with respect to the groove 2a may be in the opposite direction to that shown in Fig. 2; In this case, the radius r of the chip 3a is increased relative to the inclination shown in FIG. 1, so the operation is easy.

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, although the term "short sliding surface" will be used below, the term "short sliding surface 2c" means that the vane 3 is in the groove 2.
As is clear from the structure of FIG. 1, the length guided in the groove a is short on the 2c side of the groove 2a and long on the 2d side, so the short side is called a "short sliding surface". ", and the long side 2d is named "long sliding surface".

In the state shown in FIG. 2, the vane 3 is inclined with respect to the normal O to j to the cam surface 1a, and the cam surface 1
The shape of the chip 3a at the corner point j in contact with a is
In order to achieve the above 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 line Oj.

The location of center k will be discussed below.

In FIG. 2, the normal line O~j, the eccentric direction reference line 2b, and the extension line j~f of the side surface 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=R ₁ , of=x ₁ and hk are approximately the distance t ₂₀ of the perpendicular line drawn from point k to the side of vane 3 Therefore, rearranging equation (1) results in r=R ₁ ×t ₂₀ /x ₁ (2).

Furthermore, as is clear from FIG. 1, x ₁ in equation (2) is the value obtained by subtracting c 3 from the dimension x ₀ given at the time of design, and _{c 3 is} an unknown quantity. Therefore, c ₃ is calculated below.

Triangle abc and triangle cde are similar, and c~
The length b is approximately the difference in length between the groove 2a and the vane 3 in the rotor rotation direction to
It can be regarded as −t=c ₁ . Therefore, d ₁ /c ₁ = (to-c ₁ ) /c ₂ or c ₂ = (to-c ₁ )×c ₁ /d ₁ (3) Also, since triangle abc and triangle egf are similar, d ₁ / c ₁ = (d ₂ + c ₂ ) / c ₃ , so c ₃ = (d ₂ + c ₂ ) × c ₁ / d ₁ (4), and substituting formula (3) into formula (4), c ₃ = (c ₁ / d ₁ ) ² × (to−c ₁ ) + (c ₁ / d ₁ ) × d ₂ (5).

Here, x ₁ = x ₀ − c ₃ , so by substituting equation (5) into this, x ₁ = x ₀ − (c ₁ / d ₁ ) ² × (to−c ₁ ) − (c ₁ / d ₁ ) × d ₂ (6) is obtained.

Substituting equation (6) into equation (2) above, equation (2) contains two unknowns, r and t ₂₀ , so a new relational equation for r and t ₂₀ is found 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.

The groove 2a is perpendicular to the eccentric direction reference line 2b, and the groove 2a is located on the side far from the center O (first
Since the vane 3 is in the most inclined state with respect to the cam surface 1a when the position of the groove 2a on the lower side of the diagram is Not,
The curvature of the contacting portion of the chip 3a must be the radius r as described above. Further, in this case as well, the center k of the radius r exists on the circumferential circle 3b, and the relative position of the point h with respect to the vane 3 must be the same as that in FIG. 2.

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

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, y ₁ /om=t ₃ /km (7) where om=R ₁ and km=r and t ₃ is the distance between nk. Therefore, rearranging equation (7) yields r=R ₁ ×t ₃ /y ₁ (8).

Here, y ₁ = y ₀ − c ₄ (9), and since c ₄ is an unknown quantity, the following unknown quantity c ₄ is found from Figure 3. Since triangle auv and triangle aqs are similar, c ₁ /d ₃ = c ₄ / (d ₃ + d ₄ ) or c ₄ = c ₁ × (d ₃ + d ₄ )/d ₃ (10). Therefore, from equations (9) and (10), we obtain y ₁ =y ₀ −(c ₁ /d ₃ )×(d ₃ +d ₄ ) (11).

Also, a perpendicular line drawn from point k to the side of vane 3
The length of kp can be considered approximately equal to nk, and the distance between pk is the circumferential thickness t of the vane.
Since it is the sum of t ₂₀ and t 20 explained in FIG. 2, t ₃ ≈t+t ₂₀ (12).

Therefore, from equations (8) and (12), we obtain r=R ₁ × (t+t ₂₀ )/y ₁ (13), and finally from equations (2) and (13), t ₂₀ = x ₁ × t/(y ₁ −x ₁ ) (14) and r=R ₁ ×t/(y ₁ −x ₁ ) (15), and in equations (14) and (15), x ₁ and y ₁ are (6)
It can be obtained from equation (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 (14) and (15), and when actually designing the shape of the tip 3a, use equation (15). Using the value of the radius r found in this way, draw an arc centered around the corner point j on the chip 3a, and then draw the vane 3 on the side of the corner point j with the dimension _t20 found from equation (14). A parallel line is provided from the side surface of , and the intersection of the parallel line and the arc becomes the center k to be found.

Also, considering the machining accuracy and total assembly error of r and _t20 , it is desirable to multiply the right side of equation (15) by a constant C of 1.0 to 0.8 and use it on the safe side.

Figure 4 shows two types of vacuum pumps 11 and 21.
Heat generation ratio of the entire vacuum pump (ratio to maximum heat generation) when conventional vanes are installed on each
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: tip, 3b: circumference, 3c: bottom.
4: Displacement room, 5: Arrow. R ₁ : radius of curvature of cam surface 1a, R ₂ : outer diameter (radius) of rotor 2, eo: offset amount of vane 3, r: radius of curvature of tip 3a, x ₀ : long sliding surface 2d from reference line 1b _y0 : Dimension from reference line 1b to short sliding surface 2c, o and k: Center, t: Thickness of vane 3 in rotational direction 5, to: Thickness of vane groove 2a in rotational direction 5, t ₂₀ : Length of perpendicular line drawn from center k to side of vane 3, a, b, c, d, e, f, g, h,
j, m, n, p, q, s, u and v: points, d ₁ and d ₃ : length guided in the groove 2a of the vane 3, d ₂ and d ₄ : from the bottom 3c of the vane 3 Length to the eccentric direction reference line 2b.

Claims (1)

[Claims] 1. An amount eo offset parallel to a plane in the direction of the drive shaft radially from the rotation center of the rotor.
A groove is cut with a distance of The shape of the cam surface that performs this is a circular shape with a radius R ₁ in the rotating surface, the radius to the radial outer circumference of the rotor is R ₂ , and the radius in the circumferential direction of the rotation in the groove is R 2 The amount eo has a relationship greater than {R ₁ −R ₂ + (to/2)}, where the groove width is to, and in the radial direction, from the center of the R ₁ on the cam surface of the rotor The amount of eccentricity E has the relationship E=R ₁ - R _2. In the above configuration, t: thickness of the vane in the rotational direction, _d1 : relative to the reference line in the eccentric direction of the rotor. When the groove is located vertically and the groove 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 in the groove, d ₂ : When the groove is in a position showing the dimension d ₁ , the length from the bottom of the vane to the eccentric reference line x ₀ : When the groove is in a position showing the dimension d ₁ where, the length between 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, d ₃ : the eccentricity When the groove is located perpendicular to the direction reference line and the groove is located on the side far from the center of the circular shape, the length of the vane guided by the short sliding surface, d ₄ : When the groove is in a position showing the dimension _d3 , the length from the bottom of the vane to the eccentric reference line, _y0 : When the groove is in a position showing the dimension _d3 . where: the length from the vertical reference line to the short sliding surface, c ₁ : to-t, r: radius of curvature at the tip of the vane that is convex in the radial direction in the rotational direction surface, t ₂₀ : Length from the side surface on the long sliding surface side of the vane to the center of curvature of r, c: constant of 0.8 to 1.0, as r=c×R ₁ ×t/(y ₁ −x ₁ ) t ₂₀ = x ₁ × t / (y ₁ − x ₁ ) where x ₁ = x ₀ − (c ₁ / d ₁ ) ² (to − c ₁ ) − {(c ₁ / d ₁ ) × d ₂ } A vane pump motor characterized by having the following relationship: y ₁ = y ₀ −(c ₁ /d ₃ )(d ₃ +d ₄ ). 2. The vane pump motor according to claim 1, wherein the rotor is driven by an automobile engine. 3. The lubricating oil that lubricates the sliding parts of the vanes is
The vane pump motor according to claim 2, wherein the vane pump motor shares lubricating oil that lubricates rotating and sliding parts of the engine.