A double claw compressor for fuel cells

Abstract

The application discloses a double-claw claw compressor for fuel cells, which is composed of a first rotor (1), a second rotor (2), a cylinder (3), a rear end cover (4), an exhaust port adjusting valve (5) and a front end cover (6). The first rotor (1) and the second rotor (2) have the same end face profile line, and the profile line of the two rotors is composed of 14 curves, the curves are smoothly connected and can be correctly engaged. The rear end cover (4) is provided with an exhaust port (401) and an adjusting valve hole (402), the size of the exhaust port (401) is adjusted by the sliding of the exhaust port adjusting valve (5) in the adjusting valve hole (402), so that the exhaust pressure is changed. The rotors of the double-claw claw compressor have good self-engagement, the rotors are convenient to process and manufacture, and the variable pressure ratio of the exhaust port expands the working condition application range of the claw compressor.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of compressor engineering, and particularly relates to a double-claw claw compressor for fuel cells. BACKGROUND

[0002] The claw compressor is compact in structure, dry and oil-free, and is often used as an air compressor and a hydrogen circulation pump in a fuel cell system, and is a key technology of the fuel cell system. As a positive displacement fluid machine, the claw compressor completes the processes of air suction, compression and exhaust through the periodic change of the volume of the working chamber formed by a pair of mutually meshing claw rotors, a rotor, a cylinder and an end cover under the driving of a synchronous gear.

[0003] The two mutually meshing claw rotors directly determine the working performance of the claw compressor. Patent CN106948863B proposes a full-smooth asymmetric double-claw rotor, which realizes full-smoothness of the claw rotor, reduces the clearance volume, and improves the mechanical properties of the claw tip. Patent CN114776588A discloses an eccentric circular arc claw compressor, which adopts an eccentric circular arc-cycloid-circular arc profile composition method to eliminate the sharp points of the rotor and optimize the working process of the compressor. The above claw compressors and double-claw rotors have the following problems: ① The two double-claw rotors have different profile compositions and are not self-conjugate, increasing the machining difficulty of the rotors; ② The exhaust ports of the claw compressors are fixedly opened and cannot change the exhaust pressure, and changes in working conditions will cause over-compression or under-compression. SUMMARY

[0004] To solve the above problems, the present application proposes a double-claw claw compressor for fuel cells, which has the following advantages: ① The two double-claw rotors have the same end face profile and are self-meshing, reducing the machining difficulty of the rotors; ② The profiles of the two rotors are composed of 14 curves, and each curve is smoothly connected, improving the mechanical properties of the rotor; ③ The size of the exhaust port is adjusted by the sliding of the exhaust port adjusting valve in the adjusting valve hole, thereby changing the exhaust pressure; and ④ The elliptical arc is used at the claw tip of the double-claw rotor, which not only improves the mechanical properties of the rotor, but also forms a leakage channel at the end of the mixing process, allowing the high-pressure gas in the clearance to leak into the constant-volume delivery chamber, thereby reducing the pressure in the clearance. The proposed double-claw claw compressor is of great significance in reducing the machining cost of the claw rotor, widening the working condition adaptation range of the claw compressor and reducing the power consumption of the compressor.

[0005] The technical scheme adopted by the present application to solve its technical problems is as follows:

[0006] A double-claw claw compressor for fuel cells, comprising a first rotor, a second rotor, a cylinder, a rear end cover, an exhaust port adjusting valve and a front end cover.

[0007] The end face profile of the first rotor is composed of 14 curves, and in the counterclockwise direction, they are in turn: the envelope line AB of the first elliptic arc, the first elliptic arc BC, the first claw top circular arc CD, the first eccentric involute DE, the first pitch circular arc EF, the envelope line FG of the first eccentric involute, the first claw bottom circular arc GH, the envelope line HI of the second elliptic arc, the second elliptic arc IJ, the second claw top circular arc JK, the second eccentric involute KL, the second pitch circular arc LM, the envelope line MN of the second eccentric involute, and the second claw bottom circular arc NA.

[0008] The end face profile of the second rotor is the same as that of the first rotor (1), and in the counterclockwise direction, they are in turn: the envelope line ab of the third elliptic arc, the third elliptic arc bc, the third claw top circular arc cd, the third eccentric involute de, the third pitch circular arc ef, the envelope line fg of the third eccentric involute, the third claw bottom circular arc gh, the envelope line hi of the fourth elliptic arc, the fourth elliptic arc ij, the fourth claw top circular arc jk, the fourth eccentric involute kl, the fourth pitch circular arc lm, the envelope line mn of the fourth eccentric involute, and the fourth claw bottom circular arc na.

[0009] The rear end cover is provided with an exhaust port and an adjusting valve hole, the profile curve of the exhaust port is composed of four curves, and in the counterclockwise direction, they are in turn: the envelope line OP of the elliptic arc, the first straight line PQ, the second straight line QR, and the third straight line RO; the exhaust port penetrates through both sides of the rear end cover, and the adjusting valve hole is located on one side of the rear end cover; the width b and the height d of the exhaust port adjusting valve are equal to the width b1 and the height d1 of the adjusting valve hole, b=b1 and d=d1; the length h of the exhaust port adjusting valve and the relationship between the minimum length h1 and the maximum length h2 of the adjusting valve hole are: h1<h<h2.

[0010] The exhaust port adjusting valve is installed in the adjusting valve hole and can slide in the adjusting valve hole, so as to change the area of the exhaust port and further change the starting time of exhaust.

[0011] In the working process of the claw compressor, the profile lines of the first rotor and the second rotor can realize correct engagement, and the engagement relationship is that the envelope line AB of the first elliptic arc, the first elliptic arc BC, the first claw top circular arc CD, the first eccentric involute DE, the first pitch circular arc EF, the envelope line FG of the first eccentric involute, the first claw bottom circular arc GH, the envelope line HI of the second elliptic arc, the second elliptic arc IJ, the second claw top circular arc JK, the second eccentric involute KL, the second pitch circular arc LM, the envelope line MN of the second eccentric involute, and the second claw bottom circular arc NA of the first rotor are respectively engaged with the fourth elliptic arc ij, the envelope line hi of the fourth elliptic arc, the third claw bottom circular arc gh, the envelope line fg of the third eccentric involute, the third pitch circular arc ef, the third eccentric involute de, the third claw top circular arc cd, the third elliptic arc bc, the envelope line ab of the third elliptic arc, the fourth claw bottom circular arc na, the envelope line mn of the fourth eccentric involute, the fourth pitch circular arc lm, the fourth eccentric involute kl, and the fourth claw top circular arc jk of the second rotor (2).

[0012] The claw compressor for fuel cell, with the rotation center O1 of the first rotor as the origin to establish the coordinate system O1xy, the profile line equation of the first rotor is as follows:

[0013] 1) The envelope line AB of the first elliptic arc has the equation as follows:

[0014] In the formula, M AB is the first rotation matrix, is the envelope line of the initial elliptic arc, and is as follows:

[0015]

[0016]

[0017] In the formula, is the first envelope condition, and is as follows:

[0018]

[0019] 2) The equation of the first elliptic arc BC is as follows:

[0020] In the formula, M BC is the second rotation matrix, is the initial elliptic arc, and is as follows:

[0021]

[0022]

[0023] 3) The equation of the first claw top circular arc CD is as follows:

[0024] 4) The equation of the first eccentric involute DE is:

[0025] wherein: the base circle radius R of the involute b , the offset distance h of the involute, the rotation angle γ of the involute around the center O of the base circle b and the relationship between the radius R1 of the claw top circle, the radius R2 of the pitch circle, the central angle θ of the involute CD is:

[0026]

[0027] 5) The equation of the first pitch circle arc EF is:

[0028] 6) The equation of the envelope FG of the first eccentric involute is:

[0029]

[0030] wherein: is the second envelope condition formula, as follows:

[0031]

[0032] 7) The equation of the first claw bottom circle arc GH is:

[0033] 8) The equation of the envelope HI of the second elliptical arc is: HI (t) = M0·r AB (t)

[0034] 9) The equation of the second elliptical arc IJ is: IJ (t) = M0·r BC (t)

[0035] 10) The equation of the second claw top circle arc JK is: JK (t) = M0·r CD (t)

[0036] 11) The equation of the second eccentric involute KL is: KL (t) = M0·r DE (t)

[0037] 12) The equation of the second pitch circle arc LM is: LM (t) = M0·r EF (t)

[0038] 13) The equation of the envelope MN of the second eccentric involute is: MN (t) = M0·r FG (t)

[0039] 14) The equation of the second claw bottom arc NA is: r NA (t) = M0 r GH (t)

[0040] In the formula, M0 is a third rotation matrix, as follows:

[0041]

[0042] The above: t is an angle parameter, rad; R1 is a claw top arc radius; R2 is a pitch circle arc radius; R3 is a claw bottom arc radius; R b is a base circle radius of the involute; the following relationships are satisfied: 2R2 = R1 + R3; θ is a central angle of the involute CD, rad; h is a distance between a base circle center of the involute CD and a pitch circle arc center; γ is a rotation angle of the involute; α is a rotation angle of the first rotation matrix, rad; β is a rotation angle of the second rotation matrix, rad; m is a major axis length of the initial elliptical arc; and n is a minor axis length of the initial elliptical arc.

[0043] The double-claw claw compressor for the fuel cell uses a rotation center O2 of the second rotor as an origin to establish a coordinate system O2xy, and the profile curve equation of the exhaust port is as follows:

[0044] 1) The envelope OP of the elliptical arc has the following equation: r OP (t) = M2 r AB (t)

[0045] In the formula, M2 is a fourth rotation matrix, as follows:

[0046]

[0047] 2) The equation of the first straight line PQ is as follows:

[0048] 3) The equation of the second straight line QR is as follows:

[0049] 4) The equation of the third straight line RO is as follows:

[0050] The above: C is a distance of the second straight line from the center O2; R4 is a distance of the first straight line from the center O2; the size of R4 is between the pitch circle arc radius R2 and the claw bottom arc radius R3, R3 < R4 < R2; and the size of C is determined by the intersection point of the rotor profile line of the second rotor at the end of the constant volume process and the first straight line.

[0051] A claw vacuum pump uses the first rotor, the second rotor, the rear end cover, and the exhaust port adjusting valve.

[0052] The present application has the following advantages:

[0053] ①The double-claw claw compressor for fuel cell is characterized in that the smooth connection between the curves of each section of the end surface profile eliminates the wear at the sharp points and reduces the stress concentration in the working process; at the same time, the meshing types between the rotors are all changed into line and line meshing, reducing the leakage generated between the rotors in the working process.

[0054] ②The double-claw claw compressor for fuel cell is characterized in that the mixing process is simple, the segmentation and combination of multiple working chambers are reduced, and the power consumption in the working process is reduced.

[0055] ③The double-claw claw compressor for fuel cell is characterized in that a leakage passage is formed at the beginning of the mixing process, the high pressure generated by over-compression in the clearance is reduced, and the power consumption is reduced; at the same time, the leaked gas has a pressurizing effect on the gas in the constant-volume delivery chamber.

[0056] ④The double-claw claw compressor for fuel cell is characterized in that the two rotor profiles are completely the same, have self-meshing property, are convenient for rotor machining, and reduce the machining cost.

[0057] ⑤The double-claw claw compressor for fuel cell is characterized in that the combination of the exhaust port, the adjusting valve hole and the exhaust port adjusting valve realizes the change of the size of the exhaust port, so that the exhaust pressure can be changed, and the working condition application range of the claw compressor is expanded. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 It is a structure schematic diagram of a double-claw claw compressor for fuel cell.

[0059] Figure 2 It is a profile diagram of a first rotor (1) of a double-claw claw compressor for fuel cell.

[0060] Figure 3 It is a meshing schematic diagram of a first rotor (1) and a second rotor (2) of a double-claw claw compressor for fuel cell.

[0061] Figure 4 It is a contour curve diagram of an exhaust port 402 of a double-claw claw compressor for fuel cell.

[0062] Figure 5 It is a structure schematic diagram of a cylinder (3).

[0063] Figure 6 It is a structure schematic diagram of a front end cover (6).

[0064] Figure 7 It is a structure schematic diagram of a rear end cover (4).

[0065] Figure 8 It is a structure schematic diagram of an exhaust port adjusting valve (5).

[0066] Figure 9 is the working schematic diagram of the exhaust start time when the exhaust port 401 is fully open.

[0067] Figure 10 is the working schematic diagram of the exhaust start time when the exhaust port 401 is half open.

[0068] Figure 11 is the working schematic diagram of the exhaust start time when the exhaust port 401 is minimum.

[0069] Figure 12 is the working schematic diagram of the exhaust end time of a double-claw claw compressor for fuel cell.

[0070] Figure 13 is the working schematic diagram of the mixing process start time of a double-claw claw compressor for fuel cell.

[0071] In the figure: 1 - the first rotor (1); 2 - the second rotor (2); 3 - the cylinder (3); 4 - the rear end cover (4); 5 - the exhaust port adjusting valve (5); 6 - the front end cover (6); 101 - the first rotor shaft hole (101); 201 - the second rotor shaft hole (201); 301 - the air inlet (301); 302 - the cylinder inner wall (302); 303 - the cylinder connecting hole (303); 401 - the exhaust port (401); 402 - the adjusting valve hole (402); 403 - the rear end cover bearing hole (403); 404 - the rear end cover connecting hole (404); 601 - the front end cover connecting hole (601); 602 - the front end cover bearing hole (602); R1 - the claw top circular arc radius; R2 - the pitch circular arc radius; R3 - the claw bottom circular arc radius; θ - the central angle of the claw top circular arc; b - the exhaust port adjusting valve width; d - the exhaust port adjusting valve height; h - the exhaust port adjusting valve length; b1 - the adjusting valve hole width; d1 - the adjusting valve hole height; h1 - the minimum length of the adjusting valve hole; h2 - the maximum length of the adjusting valve hole. DETAILED DESCRIPTION

[0072] The present application will be further described below in conjunction with the accompanying drawings.

[0073] As Figure 1The diagram shows a schematic of a dual-claw compressor for fuel cells, including: a first rotor 1, a second rotor 2, a cylinder 3, a rear end cover 4, an exhaust port regulating valve 5, and a front end cover 6; the cylinder 3 has an intake port 301, and the rear end cover 4 has an axial exhaust port 401 and a regulating valve hole 402; during the operation of the claw compressor, the first rotor 1 and the second rotor 2 perform synchronous and opposite-direction double-rotation motion in the cylinder 3, and the two rotors and the cylinder 3 form a periodically changing working chamber, and the working chamber is periodically connected to the intake port 301 and the exhaust port 401, thereby completing the intake, isochoric delivery, compression, and exhaust processes of the claw compressor.

[0074] like Figure 2 The diagram shows the end face profile of the first rotor 1. The end face profile consists of 14 curves, arranged counter-clockwise as follows: AB (envelope of the first elliptical arc), BC (first elliptical arc), CD (first claw tip arc), DE (first eccentric involute), EF (first segment arc), FG (envelope of the first eccentric involute), GH (first claw bottom arc), HI (envelope of the second elliptical arc), IJ (second elliptical arc), JK (second claw tip arc), KL (second eccentric involute), LM (second segment arc), MN (envelope of the second eccentric involute), and NA (second claw bottom arc). The end face profile of the second rotor 2 is the same as that of the first rotor 1, and in counterclockwise order are: the envelope of the third elliptical arc ab, the third elliptical arc bc, the third claw top arc cd, the third eccentric involute de, the third section arc ef, the envelope of the third eccentric involute fg, the third claw bottom arc gh, the envelope of the fourth elliptical arc hi, the fourth elliptical arc ij, the fourth claw top arc jk, the fourth eccentric involute kl, the fourth section arc lm, the envelope of the fourth eccentric involute mn, and the fourth claw bottom arc na.

[0075] A coordinate system O1xy is established with the rotation center O1 of the first rotor 1 as the origin. The compositional profile equations of the first rotor 1 are as follows:

[0076] 1) The equation of the envelope AB of the first elliptical arc is:

[0077] Where: M AB Let be the first rotation matrix. Let the envelope of the initial elliptical arc be as follows:

[0078]

[0079]

[0080] In the formula: The first envelope condition is as follows:

[0081]

[0082] 2) The equation of the first elliptical arc BC is:

[0083] wherein: M BC is the second rotation matrix, is the initial elliptical arc, as follows:

[0084]

[0085]

[0086] 3) The equation of the first claw top circular arc CD is:

[0087] 4) The equation of the first eccentric involute DE is:

[0088] wherein: the base circle radius R of the involute b , the offset distance h of the involute, the rotation angle γ of the involute around the base circle center O b , the relationship of the claw top circular arc radius R1, the pitch circle arc radius R2, and the central angle θ of the involute CD is:

[0089]

[0090] 5) The equation of the first pitch circle arc EF is:

[0091] 6) The equation of the envelope FG of the first eccentric involute is:

[0092]

[0093] wherein: is the second envelope condition formula, as follows:

[0094]

[0095] 7) The equation of the first claw bottom circular arc GH is:

[0096] 8) The equation of the envelope HI of the second elliptical arc is: HI (t) = M0·r AB (t)

[0097] 9) The equation of the second elliptical arc IJ is: IJ (t) = M0·r BC (t)

[0098] 10) The equation of the second claw top circular arc JK is: JK (t) = M0·r CD (t)

[0099] 11) The equation of the second eccentric involute KL is: r KL (t) = M0 r DE (t)

[0100] 12) The equation of the second pitch circle arc LM is: r LM (t) = M0 r EF (t)

[0101] 13) The equation of the envelope MN of the second eccentric involute is: r MN (t) = M0 r FG (t)

[0102] 14) The equation of the second claw bottom circle arc NA is: r NA (t) = M0 r GH (t)

[0103] In the formula: M0 is the third rotation matrix, as follows:

[0104]

[0105] The above: t-angle parameter, rad; R1-claw top circle radius; R2-pitch circle radius; R3-claw bottom circle radius; R b -the base circle radius of the involute; satisfy the relationship: 2R2=R1+R3; θ-the central angle of the involute CD, rad; h-the distance between the center of the base circle of the involute CD and the center of the pitch circle arc; γ-the rotation angle of the involute; α-the rotation angle of the first rotation matrix, rad; β-the rotation angle of the second rotation matrix, rad; m-the length of the major axis of the initial elliptical arc; n-the length of the minor axis of the initial elliptical arc.

[0106] As Figure 3As shown in the figure, it is a schematic diagram of the meshing of the first rotor 1 and the second rotor 2. During the operation of the claw compressor, the formed profiles of the first rotor 1 and the second rotor 2 can achieve correct meshing. The meshing relationship is that the envelope line AB of the first elliptical arc, the first elliptical arc BC, the first claw top circular arc CD, the first eccentric involute DE, the first circular arc EF, the envelope line FG of the first eccentric involute, the first claw bottom circular arc GH, the envelope line HI of the second elliptical arc, the second elliptical arc IJ, the second claw top circular arc JK, the second eccentric involute KL, the second circular arc LM, the envelope line MN of the second eccentric involute, and the second claw bottom circular arc NA of the first rotor 1 are respectively meshed with the fourth elliptical arc ij, the envelope line hi of the fourth elliptical arc, the third claw bottom circular arc gh, the envelope line fg of the third eccentric involute, the third circular arc ef, the third eccentric involute de, the third claw top circular arc cd, the third elliptical arc bc, the envelope line ab of the third elliptical arc, the fourth claw bottom circular arc na, the envelope line mn of the fourth eccentric involute, the fourth circular arc lm, the fourth eccentric involute kl, and the fourth claw top circular arc jk of the second rotor (2).

[0107] As Figure 4 shown, it is a contour curve graph of the exhaust port 401. Its contour curve consists of 4 curves, which are, in counterclockwise order: the envelope line OP of the elliptical arc, the first straight line PQ, the second straight line QR, and the third straight line RO; a coordinate system O2xy is established with the rotation center O2 point of the second rotor 2 as the origin. The contour curve equation of the exhaust port 401 is as follows:

[0108] 1) The equation of the envelope line OP of the elliptical arc is: r OP (t) = M2 · r AB (t)

[0109] In the formula: M2 is the fourth rotation matrix, as follows:

[0110]

[0111] 2) The equation of the first straight line PQ is:

[0112] 3) The equation of the second straight line QR is:

[0113] 4) The equation of the third straight line RO is: <000033​​​​Figure 5 As shown in the figure, it is a schematic structural diagram of the cylinder 3. A radial air inlet 301 is opened at the upper end of the cylinder 3. The inner wall 302 of the cylinder consists of two arcs with radii of R1 for the two circles and a center distance of 2R2. A cylinder connection hole 303 is opened on the cylinder 3 for connecting to the rear end cover 4 and the front end cover 6 by means of bolt connection.

[0116] As Figure 6 shown in the figure, it is a schematic structural diagram of the front end cover 6. A front end cover bearing hole 602 is opened on the front end cover 6 for installing a bearing; a front end cover connection hole 601 is opened on the front end cover 6 for connecting to the cylinder 3 and the rear end cover 4 by means of bolt connection.

[0117] As Figure 7 shown in the figure, it is a schematic structural diagram of the rear end cover 4. An exhaust port 401 and a regulating valve hole 402 are opened on the rear end cover 4. The exhaust port 401 penetrates both sides of the rear end cover 4, and the regulating valve hole 402 is only located on one side of the rear end cover 4; the width of the regulating valve hole 402 is b1, the height is d1, the minimum length is h1, and the maximum length is h2; a rear end cover bearing hole 403 is opened on the rear end cover 4 for installing a bearing; a rear end cover connection hole 403 is opened on the rear end cover 4 for connecting to the cylinder 3 and the front end cover 6 by means of bolt connection.

[0118] As Figure 8 shown in the figure, it is a schematic structural diagram of the exhaust port regulating valve 5. The width of the exhaust port regulating valve 5 is b, the height is d, and the length is h; the width b and height d of the exhaust port regulating valve 5 are respectively equal to the width b1 and height d1 of the regulating valve hole 402, b = b1, d = d1; the length h of the exhaust port regulating valve 5 and the minimum length h1 and maximum length h2 of the regulating valve hole 402 have the relationship: h1 < h < h2; the exhaust port regulating valve 5 is installed in the regulating valve hole 402 and can slide in the regulating valve hole 402, so as to change the area of the exhaust port 401, and further change the start time of exhaust.

[0119] As Figure 9 shown in the figure, it is a schematic working diagram of the start time of exhaust when the exhaust port 401 is fully open. At this time, the exhaust port regulating valve 5 is located at the minimum length h1 of the regulating valve hole 402, the exhaust port 401 is fully opened, the area of the exhaust port 401 reaches the maximum, and the compression ratio reached by the claw compressor is the minimum value of the adjustable compression ratio; when the exhaust port 401 is at the maximum, it is the moment when the isochoric delivery process of the second rotor 2 just ends. The shaded part formed by the second rotor 2 and the inner wall 302 of the cylinder is the isochoric delivery chamber.

[0120] As Figure 10As shown in the figure, it is the working diagram of the beginning of the exhaust when the exhaust port 401 is half open. At this time, the exhaust port adjusting valve 5 blocks a part of the exhaust port 401. With the sliding of the exhaust port adjusting valve 5 in the adjusting valve hole 402, the area of the exhaust port 401 is changed, so as to achieve the purpose of adjustable pressure ratio.

[0121] As shown in the figure, it is the working diagram of the beginning of the exhaust when the exhaust port 401 is half open. At this time, the exhaust port adjusting valve 5 blocks a part of the exhaust port 401. With the sliding of the exhaust port adjusting valve 5 in the adjusting valve hole 402, the area of the exhaust port 401 is changed, so as to achieve the purpose of adjustable pressure ratio. Figure 11 As shown in the figure, it is the working diagram of the beginning of the exhaust when the exhaust port 401 is half open. At this time, the exhaust port adjusting valve 5 blocks a part of the exhaust port 401. With the sliding of the exhaust port adjusting valve 5 in the adjusting valve hole 402, the area of the exhaust port 401 is changed, so as to achieve the purpose of adjustable pressure ratio.

[0122] Figure 12 As shown in the figure, it is the working diagram of the beginning of the exhaust when the exhaust port 401 is half open. At this time, the exhaust port adjusting valve 5 blocks a part of the exhaust port 401. With the sliding of the exhaust port adjusting valve 5 in the adjusting valve hole 402, the area of the exhaust port 401 is changed, so as to achieve the purpose of adjustable pressure ratio.

[0123] As shown in the figure, it is the working diagram of the beginning of the exhaust when the exhaust port 401 is half open. At this time, the exhaust port adjusting valve 5 blocks a part of the exhaust port 401. With the sliding of the exhaust port adjusting valve 5 in the adjusting valve hole 402, the area of the exhaust port 401 is changed, so as to achieve the purpose of adjustable pressure ratio. Figure 13 As shown in the figure, it is the working diagram of the beginning of the exhaust when the exhaust port 401 is half open. At this time, the exhaust port adjusting valve 5 blocks a part of the exhaust port 401. With the sliding of the exhaust port adjusting valve 5 in the adjusting valve hole 402, the area of the exhaust port 401 is changed, so as to achieve the purpose of adjustable pressure ratio.

[0124] The above describes the specific embodiments of the present application in combination with the drawings, but is not a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications or changes made by those skilled in the art on the basis of the technical solutions of the present application without creative labor are still within the protection scope of the present application.​

Claims

1. A twin-paw claw compressor for a fuel cell, characterized by: The compressor comprises a first rotor (1), a second rotor (2), a cylinder (3), a rear end cover (4), an exhaust port adjusting valve (5) and a front end cover (6). The end surface profile of the first rotor (1) is composed of 14 curves, which are, in sequence in the counterclockwise direction, an envelope line AB of a first elliptic arc, a first elliptic arc BC, a first claw top circular arc CD, a first eccentric involute DE, a first pitch circular arc EF, an envelope line FG of a first eccentric involute, a first claw bottom circular arc GH, an envelope line HI of a second elliptic arc, a second elliptic arc IJ, a second claw top circular arc JK, a second eccentric involute KL, a second pitch circular arc LM, an envelope line MN of a second eccentric involute, a second claw bottom circular arc NA. The end surface profile of the second rotor (2) is the same as that of the first rotor (1), which is, in sequence in the counterclockwise direction, an envelope line ab of a third elliptic arc, a third elliptic arc bc, a third claw top circular arc cd, a third eccentric involute de, a third pitch circular arc ef, an envelope line fg of a third eccentric involute, a third claw bottom circular arc gh, an envelope line hi of a fourth elliptic arc, a fourth elliptic arc ij, a fourth claw top circular arcjk, a fourth eccentric involute kl, a fourth pitch circular arc lm, an envelope line mn of a fourth eccentric involute, a fourth claw bottom circular arc na. The rear end cover (4) is provided with an exhaust port (401) and an adjusting valve hole (402). The profile curve of the exhaust port (401) is composed of four curves, which are, in anticlockwise direction, an envelope curve OP of an elliptic arc, a first straight line PQ, a second straight line QR and a third straight line RO in sequence. The exhaust port (401) penetrates through both sides of the rear end cover (4), and the adjusting valve hole (402) is only located at one side of the rear end cover (4). The width of the exhaust port adjusting valve (5) is equal to the width of the adjusting valve hole (402) b , d , b 1 d , b , b 1 d , d 1 ; the length of the exhaust port adjusting valve (5) is equal to the minimum length of the adjusting valve hole (402) h , h 1 , and the maximum length of the exhaust port adjusting valve (5) is equal to the maximum length of the adjusting valve hole (402) h 2 . h 1 h , h 2 . The exhaust port adjusting valve (5) is installed in the adjusting valve hole (402) and can slide in the adjusting valve hole (402), so as to change the area size of the exhaust port (401) and further change the starting time of exhaust.

2. A double-claw claw compressor for a fuel cell as set forth in claim 1, characterized by: In the working process of the compressor, the profile of the first rotor (1) and the second rotor (2) can realize correct meshing, and the meshing relationship is that the envelope line AB of the first elliptic arc, the first elliptic arc BC, the first claw top circular arc CD, the first eccentric involute DE, the first pitch circular arc EF, the envelope line FG of the first eccentric involute, the first claw bottom circular arc GH, the envelope line HI of the second elliptic arc, the second elliptic arc IJ, the second claw top circular arc JK, the second eccentric involute KL, the second pitch circular arc LM, the envelope line MN of the second eccentric involute, and the second claw bottom circular arc NA of the first rotor (1) are respectively meshed with the fourth elliptic arc ij, the envelope line hi of the fourth elliptic arc, the third claw bottom circular arc gh, the envelope line fg of the third eccentric involute, the third pitch circular arc ef, the third eccentric involute de, the third claw top circular arc cd, the third elliptic arc bc, the envelope line ab of the third elliptic arc, the fourth claw bottom circular arc na, the envelope line mn of the fourth eccentric involute, the fourth pitch circular arc lm, the fourth eccentric involute kl, and the fourth claw top circular arcjk of the second rotor (2).

3. A claw vacuum pump, characterized by: The first rotor (1), the second rotor (2), the rear end cover (4) and the exhaust port adjusting valve (5) of claim 1 are used.

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