JPH0814161A - Wave cam type compressor - Google Patents

Abstract

PURPOSE:To improve machining precision by facilitating machining of a cam surface on a wave cam and reducing change of machining resistance of the cam surface. CONSTITUTION:A wave cam 20 is installed on a drive shaft 3 supported on cylinder blocks 1, 2. Cam surfaces 20A, 20B of the wave cam 20 are constituted of cylindrical surfaces consisting of only protruded curved surfaces. Fitting spherical surfaces 23a, 24a to fit with a duplex head piston 6 and shoes 23, 24 having sliding flat surfaces 23b, 24b are interposed between the duplex head piston 6 stored in cylinder bores 1a, 2a and the cam surfaces 20A, 20B of the wave cam 20. The wave 20 is rotated symmetrically with rotation of the drive shaft 3, and a rotational motion is converted to a reciprocal motion of the duplex head piston 6 through the shoes 23, 24. The cam surfaces 20A, 20B are formed in the protruded curved surfaces along their overall ranges and they make linear contact with sliding flat surfaces of the shoes 23, 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wave cam type compressor in which a piston is reciprocated by the rotation of a wave cam fixed on a drive shaft.

[0002]

2. Description of the Related Art A wave cam compressor in which a piston is reciprocated by the rotation of a wave cam fixed on a drive shaft is disclosed in Japanese Patent Laid-Open No. 57-10783. In this type of compressor, rollers are interposed between the front and rear surfaces of the wave cam and the double-headed piston, and the roller is rotatably and non-separably fitted and supported by the double-headed piston. The roller rolls relative to the wave cam, and the displacement of the wave cam surface due to the rotation of the wave cam is transmitted to the double-headed piston via the roller. Due to this displacement transmission, the double-headed piston reciprocates according to the displacement curve of the wave cam surface.

The cycle displacement curve of the swash plate in the swash plate compressor is a sine wave displacement curve and a one cycle displacement curve. Therefore, the double-headed piston in the swash plate compressor only compresses once per drive shaft rotation in one head. On the other hand, the displacement curve of the cam surface of the above-described wave cam is a two-cycle displacement curve, and the double-headed piston compresses twice for one rotation of the drive shaft in one head.

As shown in FIG. 15, this wave cam 5
When the x-coordinate, the y-coordinate, and the z-coordinate are set to 0, the cam surfaces 50A and 50B of the wave cam 50 are formed by a solid curved surface represented by the following equation (1). z = f (x, y) (1) According to the equation (1), the cam surface 50A of the wave cam 50,
It means that the displacement in the drive axis direction at 50B varies not only with the x coordinate but also with the y coordinate. Here, z is the central axis of the drive shaft, x is an axis orthogonal to the drive shaft, and passes through each top dead center corresponding portion position on the cam surface where the piston is located at the top dead center position, and y is the drive shaft. And an axis that passes through each bottom dead center corresponding portion position on the cam surface on which the piston is arranged at the bottom dead center position.

[0005]

Generally, in a wave cam constituted by a three-dimensional curved surface such as the above-mentioned wave cam type compressor, its surface must be formed into a wave shape along the circumferential direction, which is complicated. You will be forced to die cast. Further, in the grinding step, since the complicated wave cam is formed, it is necessary to use a plurality of end mills having different shapes, which causes a problem of increasing the grinding time. In addition, the cam surface of the wave cam must be ground with high precision using a grindstone or the like because it is necessary to smoothly convert the reciprocating motion of the wave cam to the piston. However, since the wavy cam surface has a three-dimensional curved surface that is positively and negatively reversed with respect to the top and the valley, the circumferential length of the cam surface is set to increase as it goes outward. For this reason, the cam surface cannot be polished with a certain accuracy over the radial direction and becomes uneven. Further, such polishing has a problem that it leads to uneven wear of the grindstone, which eventually leads to deterioration of the surface roughness and shape accuracy of the cam surface.

As a means for solving this problem, Japanese Patent Laid-Open Publication No.
Japanese Patent Laid-Open No. 2-121875 discloses a technical idea of precisely finishing a wave cam with a grindstone having the same shape as that of a roller. This grindstone has a conical shape and is formed so that the relative contact speed at each point in the circumferential direction of the wave cam is constant. As a result, uneven wear of the grindstone is prevented, and in turn, precision finishing of the wave cam can be easily performed. However, since the grindstone disclosed in the above publication has a special shape called a conical shape, unlike the existing grindstone, it causes a new problem that the molding has to use unnecessary cost. . Further, there is a problem that the usable wave cam is limited by the inclination angle of the cone. Further, because of the special shape, the shape inspection of the grindstone after the dressing process also requires a considerable accuracy, which is troublesome.

The present invention has been made to solve the above problems, and its purpose is to facilitate the machining of the cam surface of the wave cam and to reduce the variation of the machining resistance of the cam surface. An object is to provide a wave cam type compressor capable of improving accuracy.

[0008]

In order to solve the above-mentioned problems, the invention as claimed in claim 1 makes the cam surface of the wave cam rotate by the rotation of the wave cam having front and rear cam surfaces fixed to the drive shaft. The gist of the wave cam type compressor that reciprocates the moored piston is that the cam surface of the wave cam is formed by a columnar surface that is formed by only a convex curved surface.

According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, a sliding surface having a spherical surface between the piston and the cam surface and slidingly contacting the cam surface is provided. The point is that a shoe having a face is interposed. According to a third aspect of the present invention, in addition to the structure of the second aspect, the cam surface of the wave cam is formed by an envelope surface of a group of spheres having a parabolic cylindrical surface as a center locus, The gist is that the distance between the spherical center of the shoe and the sliding surface and the radius of the sphere are set to be substantially equal.

According to a fourth aspect of the present invention, in addition to the configuration of the second aspect of the present invention, the cam surface of the wave cam is formed of a parabolic column surface, which is substantially on the sliding surface of the shoe. The gist is that the spherical center of the shoe is set at.

[0011]

By adopting the above construction, in the invention according to claim 1, since the front and rear cam surfaces of the wave cam are constituted by the columnar surfaces consisting of only convex curved surfaces, complicated grinding and special shape The cam surface can be processed without using a grindstone. Further, as described above, since each cam surface is formed by a convex curved surface in one direction, the grindstone can carry out surface polishing of the cam surface while suppressing the change in processing resistance to a minimum, and it is highly accurate with no deviation. Surface processing can be performed.

According to the second aspect of the present invention, in addition to the action of the first aspect of the invention, the action of the shoe interposed between the piston and the cam surface causes the rotary motion of the wave cam to reciprocate the piston. Smoothly converted to. In the inventions described in claims 3 and 4, since the cam surface of the wave cam is formed based on the columnar surface having the parabola as the conductor, in addition to the action of the invention described in claim 2, the shoe is attached. The displacement speed and acceleration in the reciprocating motion of the piston through the conversion are converted into continuous and smooth ones.

[0013]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. As shown in Figure 1,
A drive shaft 3 is rotatably supported by radial bearings 4 and 5 on the pair of clamped cylinder blocks 1 and 2. The cylinder blocks 1 and 2 have a plurality of cylinder bores 1a and 2a which are paired in the front and rear (in this embodiment, 5).
Pairs) are arrayed and formed at equal angular positions about the drive shaft 3. A double-headed piston 6 is reciprocally fitted in the cylinder bores 1a, 2a.

On the outer end surfaces of both cylinder blocks 1 and 2,
A front housing 9 and a rear housing 10 are arranged so as to close the cylinder blocks 1 and 2 via valve plates 7 and 8, and both the housings 9 and 10 and the cylinder blocks 1 and 2 are tightened and fixed by bolts 11. There is. In both housings 9 and 10, suction chambers 12 and 13 communicating with the cylinder bores 1a and 2a through suction ports 7a and 8a formed in the valve plates 7 and 8, and valves similar to the suction ports 7a and 8a. Discharge chambers 14 and 1 communicating with the cylinder bores 1a and 2a through discharge ports 7b and 8b formed in the plates 7 and 8, respectively.
And 5 are sectioned. The suction ports 7a and 8a are provided with a flap operation to the cylinder bores 1a and 2a and the suction chamber 1.
Suction valves 16 and 17 for communicating with Nos. 2 and 13 are provided, and discharge valves 18 and 19 for communicating with the cylinder bores 1a and 2a and the discharge chambers 14 and 15 by flap operation are also provided to the discharge ports 7b and 8b. Is provided.

A wave cam 20 is fixedly attached to the drive shaft 3. Thrust bearings 21 and 22 are sandwiched between the wave cam 20 and the cylinder blocks 1 and 2,
The thrust load acting on the drive shaft 3 is the thrust bearing 2
It is accepted by way of 1 and 22. Shoes 23 and 24 are interposed between the wave cam 20 and the double-headed piston 6. The surfaces of the shoes 23, 24 are fitted spherical surfaces 23a, 24a that fit into the holding recesses 6a, 6b on the inner end surface of the double-headed piston 6, and the cam surface 20 of the wave cam 20.
A sliding contact plane 23b as a sliding surface that slidably contacts A and 20B,
And the fitting spherical surfaces 23a, 24a.
Radius centers Q ₁ and Q ₂ as the spherical center of the sliding contact plane 23
It is set at the center position on b and 24b. Shoe 2
3 and 24 are fitted spherical surfaces 23 on the inner end surface of the double-headed piston 6.
It is held by fitting a and 24a together, and its movement is restricted.

As shown in FIG. 2, the front and rear cam surfaces 20A and 20B of the wave cam 20 are formed in the respective cylinder bores 1a and 2a.
2 has two cycle displacement curves F ₁ and F ₂ on the circumferential surface C ₀ of the central axis L ₁ of which the displacement is repeated alternately in the axial direction. The radial center of the array circumferential surface C ₀ is the drive axis L of the drive shaft 3.
Matches ₀ . Since the radial centers Q ₁ and Q ₂ of the fitting spherical surfaces 23a and 24a are at the centers on the sliding contact planes 23b and 24b, the radial centers Q ₁ and Q ₂ of the fitting spherical surfaces 23a and 24a are always the cycle displacement curve F ₁ , in sliding contact on the F _2. Therefore,
The reciprocating displacement of the double-headed piston 6 that reciprocates as the wave cam 20 rotates matches the cycle displacement curves F ₁ and F ₂ .

Now, as shown in FIG. 3, in the wave cam 20 of this embodiment, the uppermost 20A ₁₁ on the cam surface 20A on which the double-headed piston 6 is arranged at the top dead center position, or the uppermost 20A ₁₁ on the cam surface 20B. Within the line segment connecting the top 20B ₁₁
A curved surface whose cross-sectional shape (outline) does not change, that is, a columnar surface having the same curved line as a conductor is adopted. Here, the cam surface 2
If the central axis of the drive shaft 3 at 0A is the z-axis and the axis orthogonal to the axis passing through each top dead center corresponding part position on the cam surface 20A where the double-headed piston 6 is located at the top dead center position is the x axis, The surface is represented by the following equation (2).

Z = f (x) (2) As is clear from the equation (2), the factor of the cylindrical surface to be considered for the three-dimensional curved surface of the above equation (1) is reduced, and the manufacturing is performed. It turns out to be easy. As shown in FIG. 4, in the wave cam 20 of the present embodiment, a shape obtained by cutting out a part of a parabolic column surface 25 having a parabola shown in the following formula (3) as a conductor is combined with front and back (front and back) surfaces. It is molded by

Z = −C ₁ · x ² + C ₂ (3) Then, by adopting the curved surface constituted by the parabolic cylinder surface 25 as described above, each lowest 20 of the cam surface 20 A is adopted.
A ₂₂ , each lowest 20B ₂₂ of cam surface 20B, each highest 20A ₁₁ of cam surface 20A, each highest 2 of cam surface 20B
0B ₁₁ is set with an angular interval of 180 °. Also, the top 20A ₁₁ and the bottom 20A of the cam surface 20A
₂₂ and the top 20B ₁₁ and bottom 20B of the cam surface 20B
₂₂ is set with an angular interval of 90 °. Each bottom 20A ₂₂ of one cam surface 20A is back-to-back with each top 20B ₁₁ of the other cam surface 20B.
Each top 20A _{11 of A} is back-to-back with each bottom 20B ₂₂ of the other cam surface 20B. Lowest 20A ₂₂ , 20
B ₂₂ is the position of the bottom dead center corresponding to the bottom dead center position of the double-headed piston 6 on the cylinder bores 1a, 2a side, and the uppermost positions 20A ₁₁ , 20B ₁₁ are the top dead center positions of the double-headed piston 6 on the cylinder bores 1a, 2a side. It becomes the position of the top dead center corresponding to.

Therefore, the cam surface 20A and the cam surface 20B
Are combined so that the convex sides come together, and the cam surface 20B
Is arranged with the cam surface 20A rotated by 90 °. Further, the cam surfaces 20A and 20B are formed by using a part of the parabolic cylinder surface 25, so that the surfaces thereof are all formed into convex curved surfaces. In order for the double-headed piston 6 to smoothly reciprocate, the radius center Q of the fitting spherical surfaces 23a, 24a of the shoes 23, 24a
It is necessary that the interval between ₁ and Q ₂ is constant. That is, it is necessary that the interval between the cycle displacement curves F ₁ and F ₂ is constant everywhere when viewed in the drive axis L ₀ direction. For that purpose, the following conditions are required.

The cam surface 20A and the cam surface 20B of the wave cam 20 have the same shape (condition J ₁ ). Furthermore, the cam surfaces 20A, 20 for arranging the double-headed piston 6 at the top dead center position
It is necessary that the position of the top dead center corresponding part on B and the position of the bottom dead center corresponding part on the cam surfaces 20A and 20B on which the double-headed piston 6 is located at the bottom dead center position are symmetrical (condition J ₂ ). As the condition (J ₁ ), as described above, the front and rear cam surfaces 20 are combined by combining a shape in which a part of the parabolic pillar surface 25 is cut into a circle.
This has already been achieved by forming A and 20B.
Further, in order to satisfy the condition (J ₂ ), the cam surface 20A,
20B may be a sine wave curve, and in the case of the present embodiment, when the rotation angle of the wave cam 20 is θ and the stroke amount of the double-headed piston 6 is H, the rotation angle θ and the fitting spherical surface 23a of the shoes 23, 24, The relationship between the radius center Q ₁ Q ₂ of 24a and the displacement z is expressed by the following equation (4).

Since the front and rear cam surfaces 20A and 20B of the wave cam 20 have the same shape, the cam surface 2
Consider only 0A. The rotation angle θ when the double-headed piston 6 is at the top dead center position is 0 °, the z-axis coincides with the drive axis L _0, and the y-axis is the axis 25a of the parabolic column surface 25 forming the cam surface 20A. And the x-axis is parallel to the axis 25a of the parabolic cylinder surface 25 forming the cam surface 20B.

Z (θ) = (H / 2) · cos (2θ) (4) As shown in FIG. 5, when the formula (4) is projected on the xz plane, x of z (θ) is calculated. The coordinates are expressed by the following equation (5). x (θ) = Rbp · sin θ (5) Here, Rbp represents the radius of the array circumferential surface C ₀ . From the expressions (4) and (5), the relational expression between the z coordinate and the x coordinate is represented by the following expression (6).

Z (θ) = (H / 2) · cos (2θ) = (H / 2) · (1-2 · sin ² θ) ∴z (x) = (H / 2) · (1-x ^{2 / Rbp 2) = H /} 2-H · x 2 / (2 · Rbp 2) ··· (6) equation (6) represents a parabola, the following equation and equation (2) from equation (6) (7) is introduced.

C ₁ = H / (2 · Rbp ² ) C ₂ = H / 2 (7) That is, the parabolic column surface 2 whose conductor is a parabola satisfying the expression (7)
By adopting a shape in which a part of 5 is cut out in a circular shape, the double-headed piston 6 can be smoothly reciprocated.

Next, the operation of the wave cam type compressor having the above construction will be described. When the wave cam 20 is rotated along with the rotation of the drive shaft 3, the cam action causes the double-headed piston 6 to move through the shoes 23 and 24 to the cylinder bore 1.
It reciprocates in a and 2a. In the suction stroke in which the double-headed piston 6 retracts from the top dead center position to the bottom dead center position, the refrigerant gas in the suction chambers 12 and 13 pushes the suction valves 16 and 17 away from the suction ports 7a and 8a and the cylinder bores 1a and 2a.
Inhaled into. In the compression stroke in which the double-headed piston 6 moves from the bottom dead center position to the top dead center position, the cylinder bore 1
The refrigerant gas in a and 2a is pressurized to a predetermined pressure, and when reaching the predetermined pressure, it is discharged from the discharge ports 7b and 8b to the discharge chambers 14 and 15 while pushing out the discharge valves 18 and 19.

Such suction, compression, and discharge of the refrigerant gas are performed twice for one rotation of the rotating shaft by the rotation of the wave cam 20 having the two-cycle displacement curves F ₁ , F ₂ . As shown in FIGS. 6 and 7, shoes 23, 2 for converting the rotation of the wave cam 20 into the reciprocating motion of the double-headed piston 6.
4 makes relative rotation with respect to the cam surfaces 20A and 20B so that the sliding contact planes 23b and 24b always come into line contact with the cam surfaces 20A and 20B of the wave cam 20. FIG. 7 is a plan view showing a state in which the wave cam 20 is rotated 90 ° with respect to FIG. At this time, the fitting spherical surface 23 of the shoes 23, 24
Radius centers Q ₁ and Q ₂ of a and 24a slide on the cycle displacement of the cam profile shown in FIG. Cycle displacement curve F _{2 on} the cam surface 20B of the wave cam 20
Is π / 2 (not shown) with respect to the phase of the cycle displacement curve F ₁ shown in FIG. 8 by satisfying the above condition.
Therefore, the cycle displacement curves F ₁ and F _{2 have} a constant interval in the z-axis direction (that is, the drive axis direction) everywhere.

On the other hand, in the case of the conventional wave cam 26 using a three-dimensional curved surface, in the grinding and polishing process, as shown in FIG. 9, the drive shaft of the end mill or the grindstone 27 is cammed because it is necessary to deal with the wavy cam surface. It had to be placed horizontally to the plane. Therefore, a reaction force acting on the drive shaft from the cam surface to the end mill or the grindstone 27 during the grinding and polishing steps acts in the direction perpendicular to the drive shaft. As a result, the drive shaft of the end mill or grindstone 27 is flexibly deformed by the bending moment associated with the reaction force, and the contact between the end mill or grindstone 27 and the cam surface is unstable.

However, as shown in FIG. 10, in the wave cam 20 of the present invention, since the cam surface is formed only by the convex curved surface, the drive shaft of the end mill or the grindstone 28 should be arranged perpendicularly to the cam surface. You can As a result, in the grinding and polishing steps, the reaction force from the cam surface to the end mill or grindstone 28 during the grinding and polishing steps can be applied in the axial direction of the shaft that drives the endmill or grindstone 28. Therefore, the end mill or the drive shaft of the grindstone 28 can easily receive the reaction force and can perform stable surface processing.

As shown in FIG. 11, when the surface roughnesses of the conventional wave cam 26 and the wave cam 20 of the present invention are compared, the front and rear cam surfaces 20A and 20B of the present invention are all convex curved surfaces. It can be confirmed that the processing accuracy of the wave cam 20 is better. As described above in detail, according to the wave cam type compressor of the present embodiment, since the parabolic column surface 25 is adopted, the cam surfaces 20A and 20B are all formed into convex curved surfaces. Therefore, when the surface treatment of the wave cam 20 is performed, it is not necessary for the grindstone 28 to have a special shape, and the cam surfaces 20A and 20B can be polished with a constant shape accuracy. Further, unlike the conventional wave cam 26, since the cam surface is not complicated with the concave and convex curved surface, it is possible to minimize the change in the working resistance.
High-precision surface processing can be easily performed. Further, by smoothing the cam profile, the reciprocating speed 29 and the acceleration 30 of the double-headed piston 6 can be made smooth without discontinuity with respect to the cam displacement, and stable suction and compression,
Discharge can be achieved. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS.

The present embodiment differs from the first embodiment in the shape of the column surface forming the wave cam and the shoe for converting the cycle displacement of the wave cam into the reciprocating motion of the double-headed piston in the cylinder bore. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. In particular, different points will be described. The description of the same operation and effect as the first embodiment will be omitted.

Similarly to the first embodiment, the wave cam 40 in this embodiment also has a line segment connecting the respective top dead center corresponding positions on the cam surfaces 40A and 40B where the double-headed piston 6 is located at the top dead center. A curved surface whose shape (outline) of its cross section does not change, that is, a columnar surface having the same curved line as a conductor is adopted. As shown in FIG. 12, the cam surfaces 40A and 40B are a group of spheres having a radius L with a center at the upper end surface of a parabola 25 having a parabola shown in formula (6) as a conductor It is composed of an envelope surface 41 of 41. The wave cam 40 is formed by combining its envelope surface 42 with front and back (front and back) surfaces. Cam surface 40A and cam surface 4
0B is combined so that the convex side comes together, and the cam surface 4
0B is arranged with the cam surface 40A rotated by 90 °. Since the cam surfaces 40A and 40B are shaped so as to be contracted in the drive axis direction by the distance L with respect to the parabolic pillar surface 25, their surfaces 40A and 40B are all formed into convex curved surfaces as in the first embodiment. The Rukoto. Therefore, also in this embodiment, as in the first embodiment, the condition (J ₁ )
(J ₂ ) holds.

Shoes 43 and 44 shown in FIG. 13 are interposed between the wave cam 40 and the double-headed piston 6.
The surfaces of the shoes 43 and 44 are holding recesses 6 for the double-headed piston 6.
Fitting spherical surfaces 43a and 44a fitted to a and 6b, sliding contact planes 43b and 44b as sliding surfaces slidingly contacting the cam surfaces 40A and 40B of the wave cam 40, and the fitting spherical surface 43a,
A diaphragm surface 43 connecting 44a and the sliding contact planes 43b, 44b.
c, 44c, and the slide contact planes 23b, 2
4b and the throttle surfaces 43c and 44c, the sliding portions 43A and 44A
Is configured. The diaphragm surfaces 43c and 44c are the sliding contact plane 4
It is set in a wedge shape with respect to 3b and 44b. Shoe 43,
Radius centers P ₁ and P ₂ as the spherical centers of the fitting spherical surfaces 43a and 44a of 44 are the fitting spherical surfaces 43a and 44a and the sliding portion 43.
The sliding portions 43A, 44 are set at connection positions with the A, 44A, and the radius centers P ₁ , P ₂ are located at a distance L from the cam surfaces 40A, 40B of the wave cam 40.
The thickness (offset) of A is determined.

Then, similarly to the first embodiment described above, the suction, compression, and discharge of the refrigerant gas are carried out by a two-cycle displacement curve G
The rotation of the wave cam 40 having ₁ (not shown) and G ₂ is performed twice for one rotation of the rotation shaft. The shoes 43, 44 that convert the rotation of the wave cam 40 into the reciprocating motion of the double-headed piston 6 have cam surfaces 40A, 40B so that their sliding contact planes 43b, 44b are always in line contact with the cam surfaces 40A, 40B of the wave cam 40. Rotate relative to. At this time, the sliding portion 43A having the throttle surfaces 43c and 44c,
44A produces the action of drawing in the lubricating oil due to its wedge effect. Due to this lubricating oil drawing action, the shoe 4
Sliding surface 43b, 44b of 3, 44 and wave cam 40
An appropriate oil film is formed between the cam surfaces 40A and 40B of the shoes 43 and 44, and the sliding contact planes 43b and 44b of the shoes 43 and 44 are formed.
Friction resistance between the cam surfaces 40A and 40B of the wave cam 40 is minimized.

Thus, in this embodiment, the shoes 43, 4
No. 4 fitting spherical surfaces 43a, 44a and sliding contact planes 43b, 44b
By forming the diaphragm surfaces 43c and 44c between the
Lubricating oil can be easily drawn in, and a smooth reciprocating motion of the double-headed piston 6 that maintains stable suction, compression, and discharge can be achieved. Further, the smooth reciprocating motion of the double-headed piston 6 in the cylinder bores 1a, 2a is as follows.
It is possible to reduce power loss and noise.

The present invention is not limited to the above embodiments, but may be configured as follows, for example, without departing from the spirit of the invention. (1) In the above-described first and second embodiments, the cam surfaces 20A, 20B, 40A, 40 of the wave cams 20, 40 are provided.
B is all a convex curved surface, but the cam surfaces 20A, 20B, 40
The portions where A, 40B and the sliding surfaces of the shoes 23, 24, 43, 44 do not contact each other may have a concave curved surface or a flat surface.

(2) In the first and second embodiments described above, the parabolic columnar surface 25 having a parabolic conductor as the columnar surface is adopted. However, as in the above embodiment, the conductor has a symmetrical shape in the z-axis. Any curve can be used. The point is that it may be a convex curve. (3) In the second embodiment, the shoes 43 and 44 having an offset are adopted, and the sliding portions 43A and 44A are wedge-shaped to introduce the lubricating oil. However, as shown in FIG. It may be wedge-shaped with the curvatures of 43a and 44a.

(4) In the first and second embodiments described above, the sliding contact planes 23b, 24 of the shoes 23, 24, 43, 44 are arranged.
Although b, 43b, and 44b are flat, recesses may be formed in the sliding contact planes 23b, 24b, 43b, and 44b as oil reservoirs.

[0039]

As described above in detail, according to the first aspect of the invention, the machining accuracy of the wave cam can be improved by facilitating the machining of the cam surface and reducing the change in the machining resistance of the cam surface. It has an excellent effect that it can be improved. According to the invention of claim 2,
In addition to the effect of the invention described in claim 1, the rotary motion of the wave cam can be smoothly converted into the reciprocating motion of the piston by the action of the shoe interposed between the piston and the cam surface.

Further, according to the invention described in claim 3, in addition to the effect of the invention described in claim 2, the cam surface of the wave cam is formed by the envelope surface of the group of spheres whose center locus is the paraboloidal surface. Since the distance between the center of the spherical surface of the shoe and the sliding surface is the radial length of the sphere, the sliding portion of the shoe can be formed in a wedge shape or the like. As a result, it is possible to easily achieve the drawing of the lubricating oil introduced between the sliding surface of the shoe and the cam surface of the wave cam. Also, by setting all the contact between the sliding surface of the shoe and the cam surface of the wave cam to be line contact, the contact resistance between the sliding surface of the shoe and the cam surface of the wave cam can be made constant throughout. It has an excellent effect that the reciprocating motion of the piston can be made smooth.

According to the invention described in claim 4, in addition to the effect of the invention described in claim 2, since the cam surface of the wave cam is formed by a parabolic column surface having a parabola as a conductor,
A cycle displacement curve with sinusoidal displacement can be adopted. Also, by setting all the contact between the sliding surface of the shoe and the cam surface of the wave cam to be line contact, the contact resistance between the sliding surface of the shoe and the cam surface of the wave cam can be made constant throughout. It has an excellent effect that the reciprocating motion of the piston can be made smooth.

[Brief description of drawings]

FIG. 1 is a sectional view showing an entire compressor of a first embodiment embodying the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a perspective view of a wave cam having a pillar surface.

FIG. 4 is a schematic perspective view showing a parabolic column surface.

FIG. 5 is a schematic diagram showing a cycle displacement curve.

FIG. 6 is an enlarged plan view of a wave cam having a pillar surface.

FIG. 7 is an enlarged plan view of a wave cam having a pillar surface.

FIG. 8 is a cam profile showing a cycle displacement, a velocity distribution, and an acceleration distribution of a wave cam by a column surface.

FIG. 9 is a plan view showing a polished state of a wave cam with a three-dimensional curved surface.

FIG. 10 is a plan view showing a polished state of the wave cam by the pillar surface.

FIG. 11 is a graph showing the surface roughness of a wave cam having a cylindrical surface and a wave cam having a three-dimensional curved surface.

FIG. 12 is a main part plan view showing a wave cam according to a second embodiment.

FIG. 13 is an overall plan view showing a shoe.

FIG. 14 is an overall plan view showing another shoe.

FIG. 15 is a perspective view of a main part showing a conventional wave cam having a three-dimensional curved surface.

[Explanation of symbols]

3 ... Drive shaft, 6 ... Double-headed piston, 20, 40 ... Wave cam, 20A, 20B, 40A, 40B ... Cam surface, 2
3, 24, 43, 44 ... Shoes, 23a, 24a, 43
a, 44a ... Fitting spherical surface, 23b, 24b, 43b, 44
b ... sliding plane, 25 ... parabolic cylinder, 41 ... ball, 42 ... envelope _{surface, Q 1, Q 2, P} 1, P 2 ... center of radius.

Claims (4)

[Claims] 1. A wave cam compressor in which a piston moored to the cam surface of a wave cam reciprocates by rotation of a wave cam having front and rear cam surfaces fixed to a drive shaft, wherein the cam surface of the wave cam is A wave-cam type compressor characterized in that it is composed of a columnar surface consisting of only convex curved surfaces. 2. A shoe having a spherical surface between the piston and the cam surface, and having a sliding surface in sliding contact with the cam surface is interposed.
Wave cam compressor described in. 3. The cam surface of the wave cam is composed of an envelope surface of a group of spheres whose center locus is a parabolic cylinder surface,
The wave cam compressor according to claim 2, wherein the distance between the center of the spherical surface of the shoe and the sliding surface and the radius of the sphere are set to be substantially equal to each other. 4. The cam surface of the wave cam is formed of a parabolic cylinder surface, and a spherical center of the shoe is set on a substantially sliding surface of the shoe. Wavecam compressor described.