JP2615879B2 - Scroll compressor and method for machining spiral part of movable scroll - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a scroll compressor and a method of machining a spiral portion of a movable scroll thereof.

[Prior Art] In order to avoid an increase in the diameter of the scroll type compressor as a whole, the end portion of a spiral part erected on the disk-shaped base end wall of the scroll is designed not to protrude from the peripheral circle of the base end wall. The end portion of the spiral portion extending from the intersection of the outer wall surface of the spiral portion and the peripheral circle to the terminal side has a thinner wall than other portions. The cutting of the groove between the wall surfaces of the spiral part is performed by precision cutting the side end face of the rough groove previously formed by casting with an end mill,
When the end mill comes near the end of the spiral, the thin wall escapes outward. Therefore, after cutting, the thin wall portion that has escaped outwards backs inward, and this inner wall surface enters inside the involute curve that is the original inner wall surface curve. Such intrusion of the inner wall surface causes repeated collision interference with the other scroll, and damage to the thin wall portion is induced.

A scroll-type compression group which has attempted to solve such a problem is disclosed in Japanese Utility Model Laid-Open No. 59-142482. In this compressor, a concave portion is provided on the outer wall surface of the spiral portion of the other scroll that interferes with the terminal end of the spiral portion, and the interference of collision with the terminal end of the spiral portion is avoided by the presence of the concave portion. .

[Problem to be Solved by the Invention] However, the inner wall surface of the spiral portion provided with the concave portion is necessary for forming a closed space having a relatively high compression ratio, and the concave portion is provided in this wall portion to reduce the wall thickness. The configuration leads to a decrease in pressure resistance performance, and becomes a hindrance factor in obtaining a high compression ratio.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a scroll type compressor which can avoid breakage of a terminal end without causing a decrease in wall thickness of a portion which is essentially important for obtaining a high compression ratio.

It is another object of the present invention to provide a method of processing a spiral part which can process a spiral part of a movable scroll used in a scroll compressor into an appropriate shape.

[Means for Solving the Problems] For this purpose, in the first invention, the intersection between the start and end portions of the spiral portion erected on the disk-shaped base end wall of the orbiting scroll and the peripheral circle of the base end wall. The cutting path along the inner wall surface extending over the inner wall surface is a scroll curve, the cutting path along the inner wall surface on the terminal side from the intersection is an involute curve (E), and the inner wall surface on the terminal side than the intersection (P ₁ ). The cutting path (L ₂ ) along the curve is a curve gradually deviating outward from the extension line (e) of the involute curve (E) toward the terminal end, and the outer wall surface of the terminal end is formed around the base end. Placed on the circle (C ₁ ), and set the base circle of the involute curve (E) to (C
o), the radius of the base circle (Co) is (ro), the tangent to the base circle (Co) and passing through the intersection (P ₁ ) is (l), and the extension angle at the tangent (l) is (Θo), the extension angle at a tangent (l ₁ ) tangent to the base circle (Co) and passing through an arbitrary point on the cutting path (L ₂ ) is (θo + Δθ), and the tangent (l ₁ )
Where, assuming that the length of the lead line from the intersection with the inner wall surface (3'b) of the spiral part to the contact point of the base circle is (r ₁ ), r ₁ (θo + Δθ) = ro · θo + k · Δθ where k is a constant The curve of the cutting path (L ₂ ) was set so that the above equation was satisfied.

Further, in the second invention, when machining the spiral portion of the movable scroll in the scroll compressor of the first invention, the inner wall surface of the spiral portion extends along the involute curve (E) from the starting end to the peripheral end. Cutting with a rotary cutting body,
Next, the inner wall surface of the terminal portion is the involute curve (E).
The inner wall surface of the terminal portion is cut by a rotary cutting body along the cutting path (L ₂ ) in a state where the inner wall surface is restored from the extension line (e) of FIG. To be restored to the direction that matches or approaches.

[Operation] When the end mill is moved using the involute curve as a cutting path, the end portion escapes outward at an end portion that is thinner than other portions, and the cutback moves inward after cutting along the involute curve. , Go inside the involute curve. Therefore, by moving the end mill along the cutting path that gradually shifts outward from the involute curve at the end, this deviation absorbs more than the escape of the thin wall, and the inner wall after the back of the thin wall is involuted It is avoided to go inward from the curve.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

1 is a fixed scroll, an outer wall surface 3a of the spiral portion 3 erected on the disk-shaped base end wall 2 intersects the circumference C ₁ of radius R of the base end wall 2 at the terminal end , the circumference C ₁ and the end portion 3 of the spiral portion 3 from the intersection P ₁ over the starting end of the outer wall surface 3a 'is formed so as to gradually become thinner than the other portions. Outer wall
Wall shape over the intersection P ₁ from the starting end surface of 3a is formed in an involute curve based upon the circle C _0, the intersection P ₁
Wall shape of the inner wall 3b reaching the beginning from the intersection P ₂ of a tangent l and the inner wall surface 3b of the base circle C ₀ through is formed in an involute curve E based upon the circle C _0. Terminal end 3 from the intersection P ₁ over end 'outer wall surface 3'a of coincides with the circumference C _1, the end portion 3' inner walls of than extension e of the involute curve E which forms the inner wall surface 3b The curve L is slightly shifted outward.

The inner wall surface 3'b consisting of the curve L is formed as follows.

The end mill 4 and out walls 3a, those of the groove width and the same diameter between 3b is used, the outer wall surface 3a extending from the starting end to the intersection P ₁
Cutting path is set to an involute curve, the outer wall surface 3a is formed on the involute curve to the intersection P ₁ by moving along an end mill 4 to the cutting path. In this cutting process, as shown in FIG. 2, when the end mill 4 reaches the terminal end 3 ', the terminal end 3' escapes outward,
Outer wall surface 3'a of the end portion 3 'protrudes from the circumference C ₁ indicated by a chain line outward. When the end mill 4 passes through the end portion 3 ', the end portion 3' which has escaped to the position indicated by the solid line in Fig. 2 moves back inward, so that the inner wall surface 3'b of the end portion 3 'becomes smaller than the involute curve E. entering the position indicated by the curve L ₁ of the inner two-dot chain line.

After cutting the outer wall surface 3a, the inner wall surface 3'b of the terminal end 3 'is cut by the end mill 4 as shown in FIGS. Cutting path L ₂ of the end mill 4 for cutting the inner wall surface 3'b is an inner wall surface 3'b indicated by the solid line in FIG. 3, the cutting path
L ₂ is set to the outside than the involute curve E. By the end mill 4 is moved along the cutting path L _2, flank outer wall surface 3'a of the end portion 3 'is to the position shown in solid lines in the third and fourth diagram, cutting the lines of the inner wall surface in this state Will be

Cutting path L ₂ is set as follows. Lead line r from the base circle C ₀ the length of (the tangent of the base circle C ₀₎ r (theta)
(Θ is the extension angle) is expressed by the following equation (1).

r (θ) = r ₀ θ (1) where r ₀ is the radius of the base circle C ₀ . Assuming that the extension angle θ at the tangent l is θ, the length r of the leader line on the tangent l
(Θ ₀ ) is represented by the following equation (2).

_{r (θ 0) = r 0} θ 0 ...... (2) and, the base circle C ₀ in the tangent line l ₁ of the base circle C ₀ and the tangent line l ₁
Distance from the contact point to the intersection of the tangent l ₁ and the cutting path L ₂ r ₁
(Θ ₀ + Δθ) is set as expressed by the following equation (3).

r ₁ (θ ₀ + Δθ) = r (θ ₀ ) + k · Δθ = r ₀ θ ₀ + k · Δθ (3) where Δθ is the difference between the expansion angle of the tangent l _{1 and} the expansion angle of the tangent l. , K are constants, and the extension line e of the involute curve E
Slightly larger than the clearance amount of the outer wall surface 3'a from the circumference C ₁ shown in chain line at the position of distance involute angle between the cutting path _{L 2 (θ 0 + Δθ)} δ (θ 0 + Δθ) and The value of the constant k is set as described above. Equation (3) is cutting path L ₂ is set so as to be separated into gradually outwardly from the extension line e with increasing involute angle, which is the wall thickness of the end portion 3 'is involute angle This takes into account the fact that the clearance amount δ of the terminal end portion 3 ′ during the cutting process increases as the distance increases and decreases.

'Outer wall surface 3' of thus set cutting path L ₂ termination section 3 after the cutting by moving the end mill 4 along the
a is returned to the position of the circumference C ₀ as shown in FIG. 5, the inner wall surface 3'b returns extended line e of involute curve E indicated by the one-dot chain line to a position outward. Therefore, in the sliding contact between the fixed scroll 1 and the movable scroll, the terminal end 3 'does not collide with the spiral part of the movable scroll, and the terminal end 3' is reliably prevented from being damaged. In addition, there is no particular problem in obtaining a high compression ratio even if the degree of sealing of the sealed space formed by the end portion 3 'and the spiral portion on the movable scroll side is not perfect. clearance between is allowed to some extent, the present invention has been set the cutting path L ₂ of the end portion 3 'by focusing on this point as described above.

The present invention is of course not limited to the above embodiments,
For example, the equation (3) is set so that the inner wall surface 3'b of the end portion 3 'coincides with the extension line e of the involute curve E after cutting.
It is also possible to appropriately change and set the rate of increase in the amount of separation from the extension of the involute curve E with the increase in the opening angle as the cutting path along the terminal end 3 ′.

 The present invention is also applicable to the movable scroll side.

[Effects of the Invention] As described above in detail, the present invention relates to an inner part extending from the start end of the spiral part erected on the disk-shaped base end wall of the scroll to the intersection of the end part and the peripheral circle of the base end. Since the cutting path along the wall surface is a scroll curve, and the cutting path along the inner wall surface on the terminal side from the intersection is a curve that gradually shifts outward from an extension of the involute curve as it goes toward the terminal side, Relief of the end portion at the time of machining the inner wall surface of the end portion is absorbed by cutting along the cutting path, thereby restricting the return position of the inner wall surface of the end portion after cutting to outside of the extension of the involute curve. Therefore, there is an excellent effect that breakage of the terminal portion can be surely avoided without lowering the pressure resistance of the spiral portion other than the terminal portion.

Further, according to the present invention, an appropriate inner wall surface can be formed even if the wall thickness of the terminal portion becomes smaller as the extension angle increases and the amount of clearance of the terminal portion during cutting increases.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, FIG. 1 is a front sectional view of a fixed scroll, FIG.
FIG. 3 is an enlarged front sectional view of a main part showing a cutting state of a terminal end, FIG. 4 is a cross sectional view taken along line AA of FIG. 3, and FIG. . Fixed scroll ... 1, base end wall ... 2, spiral part ... 3,
Outer wall surface ...... 3a, the inner wall surface ...... 3b, termination ...... 3 ', outer wall surface ...... 3'a, the inner wall surface ...... 3'b, intersection ...... P ₁ as intersection, involute angle ...... θo, involute curve ... E,
The extension ...... e, cutting path ...... L _2.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuaki Hoshino 2-1-1 Toyota-cho, Kariya-shi, Aichi Inside Toyota Industries Corporation (56) References JP-A-61-265376 (JP, A)

Claims (2)

(57) [Claims] An enclosed space whose volume decreases between a fixed scroll housed in a housing and a movable scroll which is housed and supported so as to be non-rotatable and revolvable opposite to the fixed scroll based on the revolution of the movable scroll. In the scroll type compressor, the intersection (P ₁ ) of the spiral from the start to the end of the spiral part erected on the disk-shaped base end wall of the orbiting scroll and the circumference (C ₁ ) of the base end wall is formed. ) Is defined as an involute curve (E), and a cutting path (L ₂ ) along the inner wall surface on the end side from the intersection (P ₁ ).
Is gradually deviated outward from the extension line (e) of the involute curve (E) toward the terminal side, and the outer wall surface of the terminal part is disposed on the peripheral circle (C ₁ ) of the base part. , The base circle of the involute curve (E)
o), the radius of the base circle (Co) is (ro), the tangent to the base circle (Co) and passing through the intersection (P ₁ ) is (l), and the extension angle at the tangent (l) is (Θo), the extension angle at a tangent (l ₁ ) tangent to the base circle (Co) and passing through an arbitrary point on the cutting path (L ₂ ) is (θo + Δθ), and the tangent (l ₁ )
Where, assuming that the length of the lead line from the intersection with the inner wall surface (3'b) of the spiral part to the contact point of the base circle is (r ₁ ), r ₁ (θo + Δθ) = ro · θo + k · Δθ where k is a constant A scroll compressor with a curved cutting path (L ₂ ) set so that the above equation holds. 2. A rotary cutting body according to claim 1, wherein the spiral wall of the movable scroll is machined along an involute curve (E) from an initial end to a peripheral end of the spiral wall of the movable scroll. Then, in a state where the inner wall surface of the terminal portion is restored inward from the extension line (e) of the involute curve (E), the inner wall surface of the terminal portion is connected to the cutting path (L ₂ ). A method of machining a spiral portion of a movable scroll of a scroll compressor, wherein the spiral wall is cut along a rotary cutting body, and the inner wall surface is restored in a direction corresponding to or approaching the extension line (e).