JPH0533119A - Method and device for nitriding vane for rotary fluid compressor - Google Patents

Abstract

PURPOSE:To form a coating film over the whole surface of a vane without upsetting the vane by inserting a recessed part formed on the end of the vane into a supporting member fixed to a base to implant the vane and forming an ionically nitrided coating film. CONSTITUTION:The recessed part 20 of a vane 2 is inserted into on a pin 34 fixed to the plate 31 of a nitriding device to implant the vane 2. The tapered side 35 of the pin 34 is engaged with the recessed part 20, and the vane 2 is semifixed to the pin 34. Accordingly, if the adjacent vanes 2 are arranged in parallel, the vanes 2 are not collided with each other nor upset. Surface treatment is carried out in these conditions, hence an ionically nitrided film is formed over the whole surface of the vane 2, the throughput is increased, and workability is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitriding method for surface-treating vanes used in a rotary fluid compressor and a nitriding apparatus for nitriding by this method.

[0002]

2. Description of the Related Art Generally, as a rotary fluid compressor having a vane, for example, an oscillating rotor compressor is known.

A vane is movably inserted in a vane groove formed in a rotor housing of a rotary fluid compressor of this type, and the vane advances and retracts from the rotor housing according to eccentric rotation of the rotor. It is like this. At that time, since the vane slides in the vane groove, the vane and the vane groove, the vane side surface and the side plate,
Also, the rotor and the tip of the vane contact each other and wear. Therefore, in the vane of the rotary fluid compressor,
It is necessary to use a material having excellent wear resistance. In such a rotary fluid compressor, in order to form a vane having wear resistance, a nitride layer is formed on the surface of a steel material having a vane shape by an ion nitriding method.

FIG. 1 is a diagram showing a conventional method and apparatus for ion nitriding a vane for a rotary fluid compressor, and FIG. 2 is a diagram showing the shape of the vane. As shown in the figure, a material having conductivity (for example, rolled steel for general structure (SS4
1): Vane 2 as an article to be processed is arranged on a circular or rectangular plate material 1 formed by JIS symbol), and this is set in a processing furnace to perform an ion nitriding process.

[0005]

However, in the conventional processing method as described above, since the vanes 2 are arranged upright on the upper surface of the plate material 1 and are not fixed to the plate material 1, the nitriding treatment is performed. When the plate material 1 with the vane 2 placed therein is set in the processing furnace, the vane 2 easily falls. Especially when the interval between the vanes 2 is narrow, when one vane 2 falls down, the other vanes 2 also fall down one after another like dominoes. Also, vane 2
The work of arranging the coins on the plate material 1 is also complicated, and this is the same as when the coins are arranged when the dominoes are defeated.

In order to prevent such an inconvenience, as shown in FIG. 3, it is possible to perform ion nitriding treatment on the net cage 4 side by side so that the side surface portion 3 of the vane 2 faces downward. (See JP-A-60-230589). However, in this case, the side surface portion 3 of the vane, which comes into contact with the mesh basket 4, is not ion-nitrided, so that the vane 2 itself becomes incomplete in function.

Further, when the vanes 2 are arranged as shown in FIG. 3, the number of vanes 2 that can be placed on the net cage 4 is reduced, and the ion nitriding ability is lowered, resulting in a manufacturing cost. Get higher

Further, Japanese Patent Laid-Open No. 3-115558 discloses a method for surface treatment of vanes, but this method has a problem that the entire surface of the vane cannot be nitrided.

The present invention has been made to solve the above problems, and a method for nitriding a vane for a rotary fluid compressor which can form an ion nitriding film on the entire surface of the vane and has a large processing capacity and good workability. The purpose is to obtain the device.

[0010]

According to the method for nitriding a vane for a rotary fluid compressor according to the present invention, a recess formed in an end portion of a vane used in the rotary fluid compressor is formed in a support member attached to a base. To insert the vane, and then form an ion nitride film on the surface of the vane.

The nitriding device for a vane for a rotary fluid compressor according to the present invention comprises a base arranged in a gas atmosphere containing nitrogen and hydrogen, and a plurality of supporting members attached to the base. And a recess formed at the end of a vane used in a rotary fluid compressor is fitted into this support member so that the vane is erected and an ion nitride film is formed on the surface of the vane. .

[0012]

According to the present invention, the spring mounting recess formed on the end face of the vane is diverted, the support member fitted into the recess is attached to the base, and the recess of the vane is fitted into the support member. As a result, a plurality of vanes are arranged on the base. Thereby, many vanes can be easily set on the base. Further, the entire surface of the vane can be surface-treated without being blocked by anything.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 4 and 5 are views showing the structure of the rotary fluid compressor, and as shown in the figure, the rotary fluid compressor 1
A rotor housing 13 is housed in the first case 12, and a vane 2 is inserted into a vane groove 14 formed in the rotor housing 13 so as to be movable back and forth in the radial direction of the case 12. The rotor 16 of the rotary fluid compressor 11 is rotatably fitted to a crank shaft 17 provided in the rotor housing 13. The vane 2 is biased inward in the radial direction by a compression coil spring 18 provided in the vane groove 14, and is moved forward and backward from the rotor housing 13 in accordance with the eccentric rotation of the rotor 16. .

The vane groove 14 and the rotor 16, which are mating members that slide on the vanes 2, are made of cast iron.
The amount of carbide is 0.10 to 6.00% by weight, the graphite shape is any type of A, D, and E of the ASTM standard, the structure of each type has tempered martensite, and the hardness is HRC40-60.

As shown in FIGS. 5 and 6, the vane 2 slides on the vane groove 14 and is parallel to both side surface portions 2a, 2a.
A front end portion 2b formed in contact with the rotor 16 and having a curved surface in cross section, an upper surface 2c and a lower surface 2d, and a rear end portion 2e biased by the compression coil spring 18. Further, one end of the compression coil spring 18 is attached to the coil spring 1 at substantially the center of the rear end 2e.
A bottomed recess 20 for biasingly supporting 8 is formed toward the tip 2b. The recess 20 is a bottomed spring mounting hole having a circular cross section with a diameter of 2 mm and a depth of 5 mm, for example. The so-called rolling piston type vane 2 as shown in FIGS. 4 and 5 is pressed against the rotor 16 by the spring 18 in order to secure the sealing property of the sliding contact portion with the rotor (also referred to as piston or roller) 16. ing.

The vane 2 has a weight percentage of, for example, C:
0.50 to 1.30%, Cr: 11.0 to 20.0%,
And a hardened steel material containing the balance Fe. The reason why C is limited to 0.20 to 1.30% is as follows.
This is because if it is 1.30% or more, the coarse Cr carbide is excessively produced and wear resistance becomes excessive, and if it is 0.50% or less, the Cr carbide is little produced and wear resistance is poor. Also,
The reason why Cr is limited to 11.0 to 20.0% is C
This is because there is a close relationship with the amount, and if the content is 20.0% or more, the formation of Cr carbide becomes excessive and the mating material is significantly worn away. When it is 11.0% or less, Cr carbides are less generated and wear resistance is poor, and corrosion resistance is low.

Further, Mo: 0.10 is further added to the vane 2.
˜1.50% and V: 0.07 to 0.15% or both of them are further improved. That is, although Mo is 0.10 to 1.50%, improvement of the hardenability is realized in this range. V is 0.0
Although it is 7 to 0.15%, effective contribution is made to carbide formation in this range. Further, in the vane 2, more desirably, Si: 1.0% or less, Mn: 1.0% or less, P: 0.06% or less, S: 0.05% or less, Ni:
It shall contain 1.0% or less. If Si exceeds 1.0%, the amount of precipitated carbides decreases and the rolling property also decreases. Ni
It is preferable that the number is large considering only toughness improvement, but it is very expensive.

Then, the vane 2 having such components
The surface of the steel material used as the material is subjected to ion nitriding treatment in order to improve the wear resistance of the vane 2. Here, the nitriding method includes a salt bath nitriding method, a gas nitriding method, an ion nitriding method, etc. Among them, the ion nitriding method can stabilize the quality, and the thickness of the compound layer and the diffusion layer can be easily adjusted. It is a treatment method that has excellent features such as controllability and no pollution problems, and in recent years this treatment method has been widely adopted.
However, this ion nitriding method is somewhat disadvantageous in terms of cost as compared with other processing methods, and therefore it is necessary to efficiently process a large number of vanes per batch. In the ion nitriding method, the furnace wall is used as an anode and the vane 2 is used as a cathode in a gas atmosphere of low pressure H ₂ and N ₂ , and a glow discharge is performed by applying a voltage of 300 to 1200 V.
Is accelerated and collides with the cathode, the vane 2 is heated, and N penetrates to form an ion nitride film on the surface of the vane 2. This ion nitriding treatment is 400 ~
A low temperature treatment of 500 ° C. and a rapid nitriding treatment are possible.

7 to 10 are views showing a first embodiment of the present invention. As shown in the drawing, a through-hole 32 for inserting a shaft is provided at a substantially central portion of a disk-shaped plate 31 as a base arranged in a gas atmosphere containing nitrogen and hydrogen.
A fan-shaped gas passage 33 is concentrically formed through the outer periphery of the through hole 32 in order to make the gas distribution in the processing furnace uniform. Further, on the upper surface of the plate 31, pins 34 as a plurality of supporting members are attached upwards at predetermined intervals in a scattered manner over the entire upper surface of the plate. The plate 31 and the pins 34 are formed of an electrically conductive material such as SS41 material, carbon steel steel material for machine structure (S45C: JIS symbol) and the like. 7 and 8, only a part of the whole pin 34 is shown and the other pins are omitted. In the method and apparatus of this embodiment, the pin 3
4, the recess 20 formed at the end (rear end 2e) of the vane 2 used in the rotary fluid compressor 11 is fitted to set the vane 2 to form an ion-nitrided film on the surface of the vane 2. I am trying to do it.

As shown in FIG. 9, the lower portion 34a of the pin 34 is
Is fixed to the plate 31 by being press-fitted or caulked, and the upper part thereof has a tapered surface 35 having a circular cross section which narrows upward. Therefore, if the concave portion 20 of each vane 2 is inserted into the tapered surface 35 of each pin 34 and attached, the vane 2 can be supported without falling. Further, at this time, if the concave portion 20 of the vane 2 is strongly inserted into the pin 34, the concave portion 20 and the tapered surface 35 are engaged with each other, and the vane 2 is in a semi-fixed state with respect to the pin 34 so that the vane 2 does not rotate and is not set. Maintain posture. Therefore, if the adjacent vanes 2 are arranged in parallel, the vanes 2 do not collide with each other. By the way, in the ion nitriding treatment, since the object to be treated is negative and the furnace body is positive to energize, it is necessary to contact the mounting base of the object to be treated with one surface or one point of the object to be treated. Then, since the tapered surface 35 of the pin 34 is in contact with the concave portion 20 of the vane 2 as the object to be processed, the ion nitriding process can be performed. Therefore, in this embodiment, the entire surfaces 2a to 2e of the vane 2 can be subjected to the ion nitriding treatment, and the portions not subjected to the ion nitriding treatment are eliminated.

As shown in FIG. 5, the vane 2 slidably slides in the vane groove 14 in the rotational direction of the rotor 16, but the rotor 16 and the tip portion 2b of the vane 2 contact each other, Further, the inlet portion 14a of the vane groove 14 and the vane 2 are
Of the vane groove 14 and the upper and lower surfaces 2c and 2d of the vane 2 contact each other. In the prior art shown in FIG. 3, a part of the side surface portion 3 (FIG. 3) and in the prior art shown in FIG. 1 and FIG. However, the side surface portion 3 and the like may be worn, but in the present embodiment, the ion nitride film is formed on the entire surface of the vane 2, and the wearability is improved, which eliminates the inconvenience.

The angle and dimensional accuracy of the taper surface 35 must be designed and manufactured in consideration of the hole tolerance of the recess 20 and the depth that does not contact the bottom of the hole, but the taper is 1/15.
In the case of, the taper is only in contact with the bottom of the hole, and the taper is 1/2
In the case of 5, it comes into contact with only the hole diameter of the rear end portion 2e.
The taper at which the bottom of the hole and the diameter of the rear end 2e contact at the same time is 1 /
Twenty. Therefore, the taper of the tapered surface 35 is preferably 1/20, for example.

Further, as shown in FIG. 10, a shaft 36 is attached to the through holes 32 of a plurality of plates 31 to form a multi-stage (usually 3 to 5 stages), which is set in a processing furnace to carry out an ion nitriding treatment. By doing so, a large amount of vanes 2 can be efficiently processed.

In this embodiment, since the vane 2 is nitrided with ionized nitrogen gas, the compound layer thickness and the diffusion layer thickness are controlled by controlling the temperature, time and H ₂ : N ₂ gas ratio. As a result, it is possible to freely control the precipitation, and it is possible to obtain a stable quality vane 2 with a small amount of dimensional change and dimensional variation. The reason why the dimensional change amount and the dimensional variation of the vane 2 which has been subjected to the ion nitriding treatment are small as described above is that the nitride layer is densely formed as compared with other salt bath nitriding treatments and the like.

11 and 12 are views showing a second embodiment of the present invention, in which a pin 37 as a supporting member in this embodiment is used.
Is a cylindrical straight pin that does not have the tapered surface 35 as shown in FIG. 9 and has a uniform cross section. The other structure is the same as that of the first embodiment. In the second embodiment, the inner peripheral surface of the concave portion 20 of the vane 2 and the pin 37 are not in pressure contact with each other, so that each of the planted vanes 2 can freely move around the pin 37 as shown by a chain line 38 in FIG. Rotate. Therefore, in this case, the chain line 38 indicating the rotation range of the vane 2
It is necessary to dispose each pin 37 so that they do not cross each other.

FIG. 13 shows the pin 3 as a supporting member.
5 and 37 ((A) and (B) in the figure), pins 39, 40 and 41 ((C) to (E) in the figure) having other shapes are shown. 39 to 41 also have a circular cross-sectional shape. The pin 41 is a straight pin having a larger diameter than the pin 37. (A) and (B) in FIG.
14A and 14B are a plan view and an elevation view showing how the pins of FIG. 13 are attached to a plate 42 as a base. In the actual device, the plate 42 (or the plate 3 in FIGS. 7 to 10) is used.
In 1), any one kind of pin among the pins 35, 37, 39, 40 is arranged.

Further, as shown in the right portion of FIG. 14, one pin 37 and two pins 41 arranged in the vicinity of the pin 37 and separated from the center line L by a distance T. , 4
A large number of assembly pins 43 configured by 1 may be arranged on the plate 42. If there is no functional problem even if the one side surface portion 2a of the vane 2 has a non-nitriding portion on both side surface portions 2a, 2a, the assembly pin 43 can be used. The vane 2 planted on the straight pin 37 is pin 3
The pair of pins 41, 41, which rotate freely with respect to 7, but serve as a rotation stop, are provided on the side surface 2 of the one side of the vane 2.
It contacts a and blocks the rotation of the vane 2. Therefore, the same effect as that of the above embodiment is obtained.

As described above, by increasing the contents of C and Cr in the steel material forming the vane 2, the amount of high-hardness Cr carbide precipitated in the steel material increases, and the ions on the surface of the steel material increase. Vane 2 by nitriding treatment
A compound layer (Fe ₄ N) is likely to be formed on the surface of, and the layer thickness is easily controlled, and as a result, the wear resistance of the vane 2 is improved. Further, since the nitriding quality is a nitriding treatment with ionized nitrogen gas regardless of the chemical reaction action, it is necessary to control the compound layer thickness, the diffusion layer thickness, the temperature, the time, and the H ₂ : N ₂ gas ratio. Due to
It is possible to freely control the precipitation and obtain the vane 2 of stable quality with a small amount of dimensional change and dimensional variation.

Furthermore, by specifying the graphite shape and structure of the mating material that slides on the vane 2, the roller 16,
An ideal wear compatibility of the vane groove 14 can be realized.

In the drawings, the same reference numerals indicate the same or corresponding parts.

[0031]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, an ion nitride film can be formed on the entire surface of the vane when the surface treatment of the vane is performed, and the processing ability is large and the workability can be improved. .

[Brief description of drawings]

1 to 3 are views for explaining a conventional technique, and FIG. 1 is a perspective view showing a conventional nitriding device for a vane for a rotary fluid compressor.

FIG. 2 is a perspective view showing an outer shape of a vane which is surface-treated.

FIG. 3 is a perspective view showing another conventional nitriding apparatus.

4 to 14 are views for explaining the present invention.
FIG. 3 is a cross-sectional view of a main part of a rotary fluid compressor having vanes.

5 is an enlarged cross-sectional view around the vane in FIG.

FIG. 6 is a perspective view showing an outer shape of a vane which is surface-treated.

7 to 10 are views showing a first embodiment of the present invention, and FIG. 7 is a perspective view showing a nitriding device of a vane for a rotary fluid compressor.

FIG. 8 is a plan view of FIG.

FIG. 9 is an enlarged cross-sectional view showing a state in which a vane is erected on a pin.

FIG. 10 is a perspective view showing a state in which the plate shown in FIG. 7 is subjected to ion nitriding treatment in a multi-stage form.

FIG. 11 is a view showing a second embodiment of the present invention and is an enlarged sectional view corresponding to FIG. 9.

FIG. 12 is a plan view of FIG. 11.

FIG. 13 is an external view showing pins of various shapes as a supporting member.

FIG. 14 is an explanatory diagram showing a state in which each pin shown in FIG. 13 is attached to a plate.

[Explanation of symbols]

2 ... Vane 2e ... rear end (end) 11 ... Rotary fluid compressor 31, 42 ... Plate (base) 34, 35, 37, 39 to 41 ... Pin (support member) 43 ... Assembly pin (support member) 20 ... Recess

Claims (2)

[Claims] 1. A support member attached to a base is fitted with a recess formed in an end portion of a vane used in a rotary fluid compressor to set up the vane, and then the surface of the vane is ion-nitrided. A method for nitriding a vane for a rotary fluid compressor, which comprises forming a coating film. 2. A base, which is disposed in a gas atmosphere containing nitrogen and hydrogen, and a plurality of support members attached to the base, and which is used for a rotary fluid compressor. A vane nitriding apparatus for a rotary fluid compressor, characterized in that a recess formed at an end of a vane is fitted into the vane so that the vane is set up to form an ion nitriding film on a surface of the vane.