JPH084668A - Scroll type fluid machine - Google Patents

Abstract

PURPOSE:To eliminate the noise due to the contact of scroll bodies by operating a scroll type fluid machine in such a way that at the time of steady operation it can be driven while avoiding liquid compression or the like and also while maintaining a prescribed gap between the respective scroll bodies. CONSTITUTION:The eccentric shaft part 41 of a crankshaft 4 is fitted to the end part of the crankshaft 4, and an eccentric cam 6 is arranged so as to be fitted to a bearing sleeve 33 that has been formed on the back surface of a movable scroll 3. The eccentric cam 6 is eccentrically turned in accordance with the rotating drive of the crankshaft 4 while being oscillated around the eccentric shaft part 41 in the direction the gap between the scroll bodies 21 and 31 is changed. The eccentric cam 6 is projectedly provided with a limit pin 7 for regulating this oscillation, and also the crankshaft 4 is provided with an engaging groove 8 to be fitted to the limit pin 7. During the rotation of the eccentric cam 6, the limit pin 7 is brought into contact with the groove wall of the engaging groove 8, and the gap between the respective scroll bodies 21 and 31 is kept in a prescribed minimum clearance. The engaging groove 8 is provided with an escaping space in which when the internal pressure of the scroll chamber 5 is increased, the eccentric cam 6 can be moved in the direction the gap between the respective scroll bodies 21 and 31 is widened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to clearance control of scrolls of scrolls in a scroll type fluid machine.

[0002]

2. Description of the Related Art Conventionally, a fixed scroll and a movable scroll are provided, the movable scroll is interlocked with a drive shaft via an eccentric cam, the movable scroll is revolved with respect to the fixed scroll, and the eccentric cam swings. A scroll-type fluid machine in which the problem that the spiral chamber formed by the scrolls of each scroll is abnormally high in pressure due to liquid compression or the like can be avoided by controlling the clearance between the scrolls by motion is disclosed in Japanese Patent Publication No.
It is known as described in Japanese Patent No. 3192.

In this scroll type fluid machine, as shown in FIG. 8, the center O ₁ on the rear side of the end plate A1 of the movable scroll A is set.
On the end of the crankshaft B having the same axis O as the center of the fixed scroll, an eccentricity eccentrically to the axis O of the crankshaft B is provided at the end of the crankshaft B while having the shaft A2 protruding from the shaft. A shaft portion B1 is provided, and a first eccentric hole C1 for fitting the shaft portion A2 between the crankshaft B and the movable scroll A.
And an eccentric cam C having a second eccentric hole C2 into which the eccentric shaft portion B1 is fitted.

Further, a limit pin B2 concentric with the axis O of the crank shaft B is provided at the end of the crank shaft B, and an engaging hole C3 for receiving the limit pin B2 is formed in the eccentric cam C. Then, by fitting the limit pin B2 into the engagement hole C3 with a predetermined gap, the escape swing amount at the time of abnormal high pressure in which the eccentric cam C swings around the eccentric shaft portion B1 is regulated. I am trying to do it.

Further, as shown in FIG. 9, the eccentric shaft portion B1 has a straight line connecting the center O ₂ and the center O ₁ of the shaft portion A2 acted in the spiral chamber formed by the scroll body of each scroll. Predetermined angle θ with respect to the vector of the resultant force F of the radial force F ₂ due to the fluid pressure and the load F ₁ perpendicular to it
In addition, it is provided so as to be located on the rear side in the rotation direction x of the movable scroll A with respect to the vector direction of the resultant force F.

Therefore, the eccentric cam C into which the eccentric shaft portion B1 is fitted is interlocked by the rotational drive of the crankshaft B, and the shaft portion A2 fitted into the eccentric cam C is eccentrically rotated. The orbiting movement of the movable scroll A is carried out. At this time, the shaft portion A2 and the eccentric shaft portion B1 are rotatably fitted in the first and second eccentric holes C1 and C2 of the eccentric cam C, respectively. And that the resultant force F acts, and the vector direction of the load F ₁ is located on the rear side in the rotation direction of the movable scroll A with respect to the extension line of the straight line O ₁ -O _2. Therefore, the resultant force F causes the eccentric cam C to rotate the center O ₁ of the shaft portion A2 around the center O ₂ of the eccentric shaft portion B1, and thus the center O of the crank shaft B and the shaft portion A2. The distance to the center O ₁ increases It is.

As a result, the scroll of the movable scroll A comes into contact with the scroll of the fixed scroll, and the sealing force between the scrolls is obtained.

When the inside of the spiral chamber is in an abnormally high pressure state, the radial force F ₂ hardly changes, but the load F ₁ increases, so that the angle θ decreases and the center O− force to increase the distance between O _1, that is, Ftanshita becomes smaller with the increase in the load F _1, the distance between the center O-O ₁ is to be reduced. Therefore, at an abnormally high pressure, the respective spiral bodies act in the direction of separating from each other, the sealing force becomes zero or negative, and the high-pressure fluid escapes from the gap between the spiral bodies, resulting in the abnormal high pressure in the spiral chamber. Can be avoided.

[0009]

However, in the conventional scroll type fluid machine, an eccentric cam C is interposed between the crank shaft B and the movable scroll A, and the eccentric shaft portion B is provided.
By arranging 1 and the shaft portion A2 of the movable scroll A as described above, it is possible to avoid an abnormally high pressure in the spiral chamber, but the limit pin B2 that regulates the swing of the eccentric cam C is As shown by the dotted line in FIG. 9, the engaging hole C3 is positioned so as to be in a non-contact state so as to regulate the escape rocking amount at an abnormally high pressure,
At the time of steady operation, since the respective spiral bodies are brought into contact with each other by the action of the resultant force F, at the time of the steady operation, strong contact between the spiral bodies occurs, and the spiral bodies slide while contacting each other. Therefore, there is a problem that the driving noise becomes loud.

The present invention has been made in view of the above problems. An object of the present invention is to avoid abnormal high pressure in the scroll chamber of each scroll while eliminating contact between the spiral bodies during steady operation, and to eliminate operating noise. It is to provide a scroll type fluid machine capable of reducing the above.

[0011]

To achieve the above object, the invention according to claim 1 comprises a fixed scroll 2 having scrolls 21 and 31, and a movable scroll 3, and a crank is provided on the back surface of the movable scroll 3. In a scroll type fluid machine in which a bearing cylinder 33 that receives the eccentric shaft portion 41 of the shaft 4 is provided, and the eccentric shaft portion 41 is rotatably fitted in the bearing cylinder 33, the bearing cylinder is provided at the end of the crankshaft 4. 33
An eccentric cam 6 to be fitted to the scroll body 3 of the movable scroll 3 between the eccentric cam 6 and the crankshaft 4 as the crankshaft 4 is driven to rotate.
1 and the eccentric shaft portion 41 that eccentrically rotates while swinging in a direction in which the gap between the spirals of the fixed scroll 2 and the scroll body 21 of the fixed scroll 2 is changed, while one of the crankshaft 4 and the eccentric cam 6 is A limit pin 7 for restricting the swing of the eccentric cam 6 is provided in a protruding manner, and an engaging groove 8 into which the limit pin 7 is fitted is formed on the other side, and the eccentric cam 6 rotates in the engaging groove 8. The groove wall 81 for maintaining the gap between the spiral body 21 of the fixed scroll 2 and the spiral body 31 of the movable scroll 3 at a minimum predetermined gap due to the contact of the limit pin 7, and the spiral bodies 21, Since the eccentric cam 6 provides the escape space 83 for moving the spiral body 31 of the movable scroll 3 in the direction away from the spiral body 21 of the fixed scroll 2 when the internal pressure of the spiral chamber 5 formed between 31 increases. is there.

According to a second aspect of the present invention, the limit pin 7 is projectingly provided on the eccentric cam 6 and the engaging groove 8 is formed on the crankshaft 4.

According to a third aspect of the present invention, the limit pin 7 is provided on the crankshaft 4 and the engaging groove 8 is formed in the eccentric cam 6.

[0014]

According to the first aspect of the present invention, the limit pin 7 is brought into contact with the groove wall 81 of the engaging groove 8 during steady operation,
Due to this contact, the movable scroll 3 can be revolved with respect to the fixed scroll 2 while maintaining the gap between the spiral bodies 21 and 31 at the minimum gap. Therefore, the eccentric cam 6 is moved to the eccentric shaft of the crankshaft 4. It is possible to operate in a state of being directly connected to the portion 41, and therefore, similar to the type in which the eccentric cam 6 is not used, the movable scroll 3 can be revolved and driven in a stable state, and the sliding resistance is reduced to operate. In addition to performing efficient compression, the contact between the spiral bodies 21 and 31 does not occur, so that it is possible to reduce the operating noise caused by a strong hit, rubbing due to the contact, or the like.

Further, in the engaging groove 8, the escape space 8
3 is provided, the limit pin 7 can be moved to the escape space 83 of the engagement groove 8 when the internal pressure of the spiral chamber 5 rises abnormally, and as a result, the eccentric cam 6 is The spiral bodies 21 and 31 are moved in the directions in which they separate from each other. Therefore, when an abnormally high pressure occurs, the gap between the spiral bodies 21 and 31 can be widened to allow the high pressure fluid to escape from this gap, and the abnormally high pressure due to liquid compression or the like can be effectively avoided.

According to the second aspect of the present invention, since the limit pin 7 is provided on the eccentric cam 6 and the engaging groove 8 is formed on the crankshaft 4, the scroll type fluid machine is particularly vertical type. When used, a sufficient amount of oil can be stored in the engagement groove 8. Therefore, when the limit pin 7 comes into contact with the engagement groove 8, the resistance of the oil causes the oil to act as a cushioning material for the shock absorber. And the limit pin 7
The impact of can be reduced.

According to the third aspect of the invention, the limit pin 7 is provided on the crankshaft 4 and the engaging groove 8 is formed on the eccentric cam 6, so that the eccentric shaft portion 41 and the eccentric shaft portion 41 are formed on the same plane. The limit pin 7 can be provided, and therefore, the load due to the fluid pressure can be received on the same plane, and as a result, the moment can be reduced and the durability can be improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings. The first embodiment shown in FIG. 1 is applied to a compressor as a scroll type fluid machine, in which a compression element CF is provided in an upper inner part of a hermetic casing 1, and a motor M is provided in a lower inner part.
And the compression element CF is attached to the housing 11
The casing 1 is supported via the.

The compression element CF is interposed between the fixed scroll 2 fixed to the upper part of the housing 11 and the fixed scroll 2 and the housing 11,
And a movable scroll 3 connected to the crank shaft 4 of the motor M.
Are composed of end plates 22 and 32 and scrolls 21 and 31 fixed to one outer surface of the end plates 22 and 32, respectively. The scrolls 2 and 3 are vertically moved so that the scrolls 21 and 31 mesh with each other. From the suction pipe 12 which is installed oppositely, the orbital drive of the movable scroll 3 with respect to the fixed scroll 2 changes the volume of the spiral chamber 5 formed between the spiral bodies 21 and 31, and opens the casing 1. The sucked gas fluid is sucked into the swirl chamber 5 and is compressed, for example.

The end plate 22 of the fixed scroll 2
A discharge port 23 is opened in the center of the discharge port 23, and an external discharge pipe 13 is connected to the discharge port 23, so that the movable scroll 3 revolves around the fixed scroll 2 and is introduced from the suction pipe 12 into the casing 1. The generated gas fluid is sucked into the spiral chamber 5 and compressed, and is discharged from the discharge port 23 of the fixed scroll 2 to the outside of the casing through the external discharge pipe 13.

Therefore, in the embodiment shown in FIGS. 1 to 3, an eccentric shaft portion 41, which is eccentric with respect to the axis of the crank shaft 4, is provided at the end of the crank shaft 4, and the shaft of the crank shaft 4 is provided. An eccentric cam 6 which is fitted to the eccentric shaft portion 41 so as to be swingable, and which is eccentrically rotated by the rotational drive of the crankshaft 4 at its end.
On the other hand, the eccentric shaft portion 41 is provided at the center of the lower surface of the end plate 32 of the movable scroll 3 via the eccentric cam 6.
The bearing tube 33 for receiving the
An eccentric cam mechanism in which the eccentric cam 6 in which the eccentric shaft portion 41 is fitted is fitted in the bearing 3 to support the bearing cylinder 33 as a bearing is used.

More specifically, the axis O of the crankshaft 4 is made to coincide with the center of the fixed scroll 2, while the eccentric cam 6 is swingably fitted to the eccentric shaft portion 41 of the crankshaft 4. Moreover, the bearing cylinder 33 of the movable scroll is fitted to the eccentric cam 6, and the center of the eccentric cam 6 is aligned with the center O ₁ of the movable scroll 3 as shown in FIG. the center O ₁ of the orbiting scroll 3 is eccentric to the center O of the fixed scroll 2, the center O ₁ of the movable scroll 3, as indicated by the two-dot chain line in FIG. 3, around the center O of the fixed scroll 2 By the orbital motion of revolving, the swirl chamber 5 can be compressed.

The eccentric shaft portion 41 projecting from the crankshaft 4 causes the eccentric cam 6 to rotate the spiral body 31 of the movable scroll 3 and the spiral scroll of the fixed scroll 2 as the crankshaft 4 is rotationally driven. It is projected at a position where it can be eccentrically rotated while swinging in a direction in which the gap between the spirals with the body 21 is changed. In FIG. 3, during the steady operation, the eccentric cam 6 is rotated by the centrifugal force about the axis O ₂ of the eccentric shaft portion 41 by the centrifugal force as the crankshaft 4 is rotationally driven.
The eccentric shaft portion 4 so that the eccentric shaft portion 4 swings toward, that is, in the direction opposite to the dotted arrow shown in FIG.
By projecting 1 on the crankshaft 4 and swinging the eccentric cam 6 in a direction in which the center O of the fixed scroll 2 and the center O ₁ of the movable scroll 3 are separated from each other during steady operation, The scroll 31 of the orbiting scroll 3 is made to approach the scroll 21 of the fixed scroll 2 to narrow the gap between the scrolls.

Further, as shown in FIGS. 2 to 3 and 5, a limit pin 7 for restricting the swing of the eccentric cam 6 is projected on the surface of the eccentric cam 6 facing the end surface of the crankshaft 4. On the other hand, as shown in FIGS. 2 to 4, an engaging groove 8 for receiving the limit pin 7 is formed on the end surface of the crankshaft 4.

That is, the limit pin 7 is fixed to the eccentric cam 6 by press fitting or the like, and the engagement groove 8 is formed when the eccentric cam 6 rotates eccentrically as the crankshaft 4 rotates. The eccentric cam 6 further includes the eccentric shaft portion 4
Since it is about to swing in the direction in which the spiral bodies 21 and 31 are brought into contact with each other, the limit pin 7 provided on the eccentric cam 6 has an arc shape along the locus about to move with this swing. It is formed in the groove.

The length of the engaging groove 8 is such that the eccentric cam 6 is rotated by the eccentric cam 6 during the eccentric rotation of the eccentric cam 6.
The spiral body 2 of the fixed scroll 2 when swinging around
1 and the scroll body 31 of the movable scroll 3 at a position where a minimum predetermined gap is maintained, the limit pin 7 comes into contact with the eccentric cam 6 and the swinging movement of the eccentric cam 6 in the rotation direction x is restricted. As described above, the groove wall 81 of the engagement groove 8 on the one end side is set, and when the internal pressure of the spiral chamber 5 formed between the spiral bodies 21 and 31 abnormally rises, the eccentric cam 6 is acted on. load due to internal pressure that overcomes the centrifugal force, the direction of the dotted arrow shown in FIG. 3, i.e., the closer to the center O of the center O ₁ of the orbiting scroll 3 is the fixed scroll 2, a spiral body 31 of the movable scroll 3 The fixed scroll 2
In order to swing a predetermined escape swing amount in a direction away from the spiral body 21, the limit pin 7 secures an escape space 83 capable of moving for a predetermined length, and a groove wall 82 on the other end side is set. To do.

As described above, in the first embodiment, the eccentric cam 6 swings to control the gap between the spiral bodies 21 and 31, and during normal operation, the spiral bodies 21 and 31.
When the internal pressure of the spiral chamber 5 rises abnormally while maintaining the minimum gap between them, the gap between the spiral bodies 21 and 31 is widened to allow the high pressure fluid to escape from this gap.
Liquid compression and the like can be avoided.

That is, during steady operation, while the limit pin 7 is always in contact with the groove wall 81 of the engaging groove 8,
Since the eccentric cam 6 can be eccentrically rotated, the eccentric cam 6
Can be operated in a state where it is directly connected to the eccentric shaft portion 41 of the crankshaft 4. Therefore, as in the case of the type in which the eccentric cam 6 is not used, the movable scroll 3 can be revolved and driven in a stable state. Since the dynamic resistance can be reduced and the compression can be performed with good operation efficiency, and since the spiral bodies 21 and 31 do not come into contact with each other, it is possible to reduce the operation noise caused by a strong hit, rubbing due to the contact, or the like. is there.

Further, in the engaging groove 8, the escape space 8
3 is provided, the limit pin 7 can be moved to the escape space 83 of the engagement groove 8 when the internal pressure of the spiral chamber 5 rises abnormally, and as a result, the eccentric cam 6 is The spiral bodies 21 and 31 are moved in the directions in which they separate from each other. Therefore, when an abnormally high pressure occurs, the gap between the spiral bodies 21 and 31 can be widened to allow the high pressure fluid to escape from this gap, and the abnormally high pressure due to liquid compression or the like can be effectively avoided.

Moreover, the engaging groove 8 is formed on the crankshaft 4.
In particular, when the scroll type fluid machine is used in a vertical type, since sufficient oil can be stored in the engagement groove 8, the limit pin 7 causes the groove walls 81 of the engagement groove 8 to be retained. , 82, mainly when the internal pressure of the spiral chamber 5 abnormally rises, the limit pin 7 moves the groove wall 8
In such a case, the oil acts as a buffer material to reduce the impact of the limit pin 7 by the action of the shock absorber.

Next, a second embodiment will be described with reference to FIGS. 6 and 7. The second embodiment has the same basic structure as that of the first embodiment. The difference from the first embodiment is that the limit pin 7 is provided on the crankshaft 4 and the engagement groove 8 is provided on the eccentric cam. 6 is formed.

That is, the limit pin 7 is press-fitted into the crankshaft 4 as shown in FIG. 6 or is formed integrally with the crankshaft 4, and the limit pin 7 is provided on the surface of the eccentric cam 6 facing the crankshaft 4 in the first embodiment. As in the example, the arcuate engagement groove 8 is formed.

Further, in the second embodiment, since the limit pin 7 is provided so as to project on the crankshaft 4, each spiral body 2
In order to regulate the movement of the eccentric cam 6 that tends to swing in the direction in which the contact holes 1 and 31 come into contact with each other, in the second embodiment, the engagement groove of the limit pin 7 in the first embodiment is used. It is the position opposite to the position within 8.

That is, due to the action of the centrifugal force of the eccentric cam 6, the engaging groove 8 tends to move in the rotational direction x with respect to the limit pin 7, so that the engaging groove 8 is rearward in the rotational direction. The eccentric cam 6 that tries to swing the wall surface of the end portion in a direction in which the spiral bodies 21 and 31 are brought into contact with each other.
Of the groove wall 81 for restricting the movement of the spiral body and maintaining the gap between the spiral bodies at a minimum predetermined gap.

As described above, in the second embodiment, since the limit pin 7 is provided on the crankshaft 4 and the engagement groove 8 is provided on the eccentric cam 6, the eccentric shaft portion 4 is formed on the same plane.
1 and the limit pin 7 can be provided,
Can be loaded by fluid pressure in the same plane, resulting in
The moment can be reduced and the durability can be improved.

In each of the above-mentioned embodiments, the engaging groove 8 is formed as an arcuate groove, but the engaging groove 8 is formed by forming a recess having an inner diameter capable of ensuring the escape space 83. You may

In this case, it is not necessary to form the engaging groove 8 corresponding to the locus of the limit pin 7, so that the engaging groove 8 can be easily formed.

[0038]

According to the first aspect of the present invention, during normal operation, the limit pin 7 is brought into contact with the groove wall 81 of the engagement groove 8, and this contact causes the respective spiral bodies 21, 31 to move. Since the movable scroll 3 can be revolved with respect to the fixed scroll 2 while maintaining the minimum clearance, it is possible to operate in a state where the eccentric cam 6 is directly connected to the eccentric shaft portion 41 of the crankshaft 4, Therefore, similar to the type in which the eccentric cam 6 is not used, the movable scroll 3 can be orbitally driven in a stable state, the sliding resistance can be reduced, and the compression can be performed with good operation efficiency.
Since there is no contact between 1 and 31, strong hits,
It is possible to reduce the driving noise caused by rubbing due to contact.

Further, in the engaging groove 8, the escape space 8
3 is provided, the limit pin 7 can be moved to the escape space 83 of the engagement groove 8 when the internal pressure of the spiral chamber 5 rises abnormally, and as a result, the eccentric cam 6 is The spiral bodies 21 and 31 are moved in the directions in which they separate from each other. Therefore, when an abnormally high pressure occurs, the gap between the spiral bodies 21 and 31 can be widened to allow the high pressure fluid to escape from this gap, and the abnormally high pressure due to liquid compression or the like can be effectively avoided.

According to the second aspect of the present invention, the limit pin 7 is provided on the eccentric cam 6 and the engaging groove 8 is formed on the crankshaft 4. When used in a mold, a sufficient amount of oil can be stored in the engagement groove 8. Therefore, when the limit pin 7 comes into contact with the engagement groove 8, the oil serves as a cushioning material due to the resistance of the oil to cause a shock. The shock of the limit pin 7 can be reduced by acting as an absorber.

According to the third aspect of the invention, the limit pin 7 is provided on the crankshaft 4 and the engaging groove 8 is formed on the eccentric cam 6, so that the eccentric shaft portion 41 and the eccentric shaft portion 41 are formed on the same plane. Since the limit pin 7 can be provided, the load due to the fluid pressure can be received on the same plane, and as a result, the moment can be reduced and the durability can be improved.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a compressor showing a first embodiment of a scroll type fluid machine of the present invention.

FIG. 2 is an enlarged cross-sectional view of the essential parts of the first embodiment.

FIG. 3 is a sectional view taken along line I-I in FIG.

FIG. 4 is a top view showing an end surface of the crankshaft of the first embodiment.

5 is an enlarged sectional view of a main part taken along line II-II in FIG.

FIG. 6 is an enlarged cross-sectional view of a main part showing a second embodiment.

7 is a sectional view taken along line III-III in FIG.

FIG. 8 is an explanatory diagram showing a connected state of a crankshaft and a movable scroll in a conventional scroll type fluid machine.

9 is an operation explanatory view in a state where a crankshaft side is viewed from a line IV-IV in FIG.

[Explanation of symbols]

 2 fixed scroll 21 spiral body 3 movable scroll 31 spiral body 33 bearing tube 4 crankshaft 41 eccentric shaft portion 6 eccentric cam 7 limit pin 8 engaging groove 81 groove wall 83 escape space

Claims (3)

[Claims] 1. A fixed scroll (2) having scrolls (21) (31) and a movable scroll (3), wherein an eccentric shaft portion (41) of a crankshaft (4) is provided on the back surface of the movable scroll (3). ) Is provided, and the eccentric shaft portion (41) is rotatably fitted in the bearing cylinder (33), the scroll type fluid machine comprising: An eccentric cam (6) fitted to the bearing tube (33) is provided, and the eccentric cam (6) is provided between the eccentric cam (6) and the crankshaft (4) as the crankshaft (4) is driven to rotate. The eccentric cam (6) is eccentrically rotated while swinging in a direction in which a gap between the spirals (31) of the movable scroll (3) and the spiral body (21) of the fixed scroll (2) is changed. While the eccentric shaft portion (41) is provided, the crankshaft (4 One of the eccentric cam (6) and the eccentric cam (6) is provided with a limit pin (7) for restricting the swing of the eccentric cam (6), and the other end of the engaging groove (7) is fitted with the limit pin (7). 8) forming the engaging groove (8)
During rotation of the eccentric cam (6), the limit pin (7) comes into contact with the scroll body (21) of the fixed scroll (2) and the scroll body (3) of the movable scroll (3).
Groove wall (81) for maintaining a minimum gap with the 1)
When the internal pressure of the scroll chamber (5) formed between the scrolls (21) and (31) rises, the eccentric cam (6) moves the scroll (31) of the movable scroll (3) to the fixed scroll ( A scroll type fluid machine characterized in that an escape space (83) that moves in a direction away from the spiral body (21) of 2) is provided. 2. A scroll type fluid machine according to claim 1, wherein the limit pin (7) is provided so as to project from the eccentric cam (6), and the engaging groove (8) is formed in the crankshaft (4). 3. A scroll type fluid machine according to claim 1, wherein a limit pin (7) is provided on said crankshaft (4) and an engaging groove (8) is formed on said eccentric cam (6).