JPH0979042A - Screw type supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce starting torque by a compact and simple structure in which a bypass and internal compression between intake/delivery ports can be opened and further a bypass pressure and internal compression opening pressure can be also adjusted with no pipe required. SOLUTION: A screw type supercharger is actuated by connecting an electromagnetic clutch 10 to be constituted by compressing air sucked from an intake port in a compression chamber 4 in an axial direction by a pair of screw type female/male rotors 2, 3 meshed with each other and supplying compressed air to an engine from a delivery port 9. Here in this constitution, a bypass passage 6, receiving a bypass valve 5 connecting a side of the intake port 8 and a side of the delivery port 9 when the supercharger is inoperative, is juxtaposed with the compression chamber 4, also it is made to communicate with the bypass passage 6 associated with opening of the bypass bypass valve 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention operates by connecting an electromagnetic clutch to compress air sucked from an intake port by a pair of screw type male and female rotors meshing with each other to supply compressed air to an engine from a discharge port. And a screw type supercharger that obtains high output.

[0002]

2. Description of the Related Art Conventionally, various types of screw type superchargers installed in an intake system of an internal combustion engine have been used. Usually, a screw type supercharger is composed of a male rotor and a female rotor each having a plurality of spiral teeth that mesh with each other on a pair of parallel rotor shafts rotating in opposite directions to form a compression portion. The air supplied from one side in the axial direction is compressed by the compression section and discharged from the other side in the axial direction to be used for high-power combustion of the internal combustion engine. Such a conventional screw type supercharger is rotationally driven by the driving force transmitted from the crankshaft via the V-belt, but usually an electromagnetic clutch is incorporated in order to reduce mechanical loss. Intermittently,
It is computer-controlled by analyzing the throttle opening, engine speed, intake air amount, etc. In order to install and use such a supercharger in the intake system of an engine of an internal combustion engine, generally, as shown in FIG. 3, an air cleaner (A / C),
Air flow meter (A / F), supercharging pressure control valve, supercharger (S /
C) is arranged, and as described above, the air compressed and pressurized in the supercharger is supplied into the engine (ENG) manifold at a predetermined air fuel efficiency together with the fuel injected near the throttle valve. In such a supercharger, in order to deactivate the supercharger, the electromagnetic clutch is turned off, and at the same time, the bypass valve B / V is opened in the supercharging path that does not require pressurization, and air is supplied from the bypass circuit. are doing. Further, even when the boost pressure to the engine exceeds a predetermined pressure, the bypass valve B / V is opened to release the preload.

However, even if the pressure difference between the front and rear of the supercharger is eliminated in such a bypass circuit to release the preload, a male member having a plurality of spiral teeth meshing with each other to form a compression portion. In the compression part of the screw type supercharger composed of a rotor and a female rotor,
Due to the residual pressure due to internal compression, if an electromagnetic clutch is connected to operate the supercharger for restarting the operation, the supercharger must be operated against the internal compression. Needed a starting torque that would be. Therefore, a large capacity electromagnetic clutch must be installed, which is uneconomical. Therefore, in order to eliminate the residual pressure due to the internal compression when the electromagnetic clutch is connected, the one described in Japanese Patent Laid-Open No. 63-21379 shown in FIG. 4 has been proposed. In this conventional example, a pair of screw rotors 22 arranged in parallel in a casing 21 and meshing with each other.
In the screw type vacuum pump using
Of the screw type rotor 22 in a closed state before penetrating the wall portion of the discharge port 29 and opening to the discharge port 29, and a relief hole 27 that communicates with the discharge port, and a valve body 25B that can be closed in the relief hole 27. When the pressure in the tooth space is weaker than this force, the valve body 25B is biased toward the rotor chamber 24 by a force of an appropriate magnitude, and the valve body 25B closes the escape hole 27.
In the opposite case, pressure means such as a coil spring 30 for opening the escape hole 27 is provided. As a result, the power value from the start of the pump to the point of use can be kept low, and the capacity of the motor or the like that drives the pump can be reduced.

[0004]

However, in the case of providing the conventional bypass circuit as shown in FIG. 3 of the former, the piping of the bypass pipe is complicated, and a space therefor is required. Further, in the latter case shown in FIG. 4, the pressure at which internal compression is released is set to a predetermined value by the coil spring 30, and the device is incorporated in the supercharging passage of the internal combustion engine as shown in FIG. Still to use in Figure 3
The bypass circuit as described in Section 1 above was required, the piping of the bypass pipe was complicated, and a space for it was also required.

Therefore, the present invention solves various problems in the conventional screw type supercharger, and enables bypass between the intake port and the discharge port and opening of internal compression without requiring piping. In addition, the economical screw type supercharger in which the starting torque is reduced by a compact and simple structure capable of adjusting the bypass pressure and the internal compression opening pressure is also provided.

[0006]

Therefore, according to the present invention, a pair of screw type male and female rotors, which are operated by the connection of an electromagnetic clutch to engage air sucked from an intake port, are compressed in an axial compression chamber. In the screw type supercharger that supplies compressed air from the discharge port to the engine,
A bypass passage accommodating a bypass valve that communicates the suction port side and the discharge port side when the supercharger is not operating is provided side by side with the compression chamber, and is linked to the opening of the bypass valve and the compression chamber. The bypass passage is configured to communicate with each other, and this is a means for solving the problem. In the present invention, an internal compression release passage for communicating the compression chamber and the bypass passage is formed near the valve seat of the bypass valve portion of the bypass valve,
The bypass valve is integrally formed with an internal compression release valve portion that opens and closes the internal compression release passage, which is a means for solving the problem.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of a screw type supercharger of the present invention, FIG. 1 is an overall view of a partial cross section of the screw type supercharger, and FIG. 2 is an enlarged view of a main part of a bypass valve. FIG. 8 is a diagram illustrating an operating state. As shown in FIG.
The screw type supercharger according to the present invention is operated by the connection of the electromagnetic clutch 10 to mesh the air sucked from the suction port 8 with each other.
(The male rotor 3 is arranged in parallel with the back side of the drawing)
With this configuration, the compressed air is compressed in the axial compression chamber 4 and the compressed air is supplied from the discharge port 9 to the engine of the internal combustion engine. In the present invention, the bypass valve 5 that connects the suction port side 8 and the discharge port side 9 when the supercharger is not operating
The bypass passage 6 accommodating the above is arranged side by side in parallel with the compression chamber 4, and the compression chamber 4 and the bypass passage 6 are communicated with each other in association with the opening of the bypass valve 5. As a specific configuration, an internal compression opening passage 7 for connecting the compression chamber 4 and the bypass passage 6 (the discharge side bypass passage 6B) in the casing 1 of the supercharger is provided in the bypass valve portion of the bypass valve 5. 5A valve seat 14
The bypass valve 5 is integrally formed with an internal compression opening valve portion 5B that opens and closes the internal compression opening passage 7, and the bypass valve 5 is connected to the discharge side bypass passage 6B. There is a valve rod 15 that extends through the suction side bypass passage 6A that extends toward the suction side with the valve seat 14 as a boundary and extends to the outside of the casing 1. The valve rod 15 is reciprocally moved in the axial direction by an actuator 13. To be done. The actuator 13 adjusts the stroke of the valve rod 15 and opens the bypass valve 5 by computer control (not shown) when supercharging is not required, when the engine is overboosted, or when the supercharging pressure is too high. It is to move in the valve direction.

On the other hand, the shafts 2A of the male and female screw rotors 2 and (3) each having an appropriate number of spiral rotor teeth are formed.
(3A is not shown) has an input pulley 11 whose left end is rotatably supported by a bearing in a casing for a synchronous gear and which is rotatably driven by a belt or the like that is hung between a crank pulley of an engine (not shown) and Rotation corresponding to the number of teeth of a proper number of spiral male rotor teeth formed on the male and female rotors 3 and 2 that mesh with each other to form the compression portion 6 via the relay shaft 12 (inversely proportional to the number of teeth) The rotation is transmitted to each rotor shaft in a distributed manner. That is, the male and female rotor shafts 2A and 3A are interlocked at a predetermined rotation speed ratio via a synchronous gear. The input pulley 11
The electromagnetic clutch 10 described above is arranged between the relay shaft 12 and the relay shaft 12 connected to the rotor shaft 2A. The electromagnetic clutch 10 is disengaged by analyzing the throttle opening, engine speed, intake air amount, and the like. Computer controlled.

Next, the operation of the present invention will be described with reference to FIGS. 1 and 2. The input pulley 11 is provided by a belt or the like that is wound around a crank pulley of an engine (not shown).
Is rotated, the female rotor shaft 2A is driven at a predetermined number of rotations, and the female synchronous gear 16 fixed to the female rotor shaft 2A is meshed with a male synchronous gear (disposed on the rear side of the drawing). Then, the male rotor 3 is accelerated at a predetermined speed increasing ratio and rotationally driven. Thus, the male and female rotors 3 and 2 which are interlockingly connected at a predetermined rotation speed ratio and mesh with each other to form the compression chamber 4 axially flow down the air flowing into the intake port 8 from the air cleaner (not shown) in the compression chamber 4. The compression / pressurization operation is performed during the operation. Then, it is discharged from the discharge port 9 to the outside of the supercharger and is used for high-power combustion of the internal combustion engine.

At the time of normal supercharging such as acceleration operation, the bypass valve 5 is in the state shown in FIG. 2A, and the intake side bypass passage 6A and the discharge side bypass passage 6B in the bypass passage 6 are provided.
Are blocked by the seating of the bypass valve portion 5A of the bypass valve 5 and the valve seat 14 of the casing 1. At this time, the bypass valve portion 5 in the bypass valve 5
An internal compression release passage 7 for communicating the compression chamber 4 and the discharge side bypass passage 6B near the valve seat 14 of A is closed by an internal compression release valve portion 5B integrally formed with the bypass valve 5. . Therefore, the air from the intake side can be supercharged to the discharge side with a high pressure difference.
Next, when the electromagnetic clutch that does not require supercharging is turned off, when the engine is overboosted, or when the supercharging pressure is abnormally high, the bypass valve rod 15 is used to bypass the actuator 13 by computer control. Valve 5
Moves in the valve opening direction on the left side of the drawing, as shown in FIG. Thereby, depending on the degree of movement stroke of the bypass valve rod 15, a predetermined degree of valve opening between the bypass valve portion 5A of the bypass valve 5 and the valve seat 14 and the internal compression release valve portion 5B of the bypass valve 5 and the internal portion thereof. Compression open passage 7
A predetermined degree of valve opening between and is obtained. FIG. 2C is a table showing the relationship between the operating state of the supercharger and the position of the bypass valve. As a result, the suction side and the discharge side through the bypass passage 6 communicate with each other to release a predetermined bypass pressure, and at the same time, release a predetermined internal compression pressure in the screw rotor. It should be noted that the opening 5C formed in the bypass valve portion 5A allows the quick air between the intake port 8 side and the compression chamber 4 side and the discharge port 9 side when the bypass valve portion 5A and the internal compression release valve portion 5B are opened. It is intended to facilitate the distribution of.

Thus, the supercharging pressure can be surely supplied at the time of normal supercharging which requires a high supercharging pressure, and at the time of turning off the electromagnetic clutch which does not require supercharging, when the engine is excessively boosted or when the supercharging pressure is abnormal. When it is extremely high, the time required for releasing the pressure is adjusted by the opening stroke of the bypass valve 5 provided inside the casing 1 of the screw type supercharger, and the bypass pressure appropriately adjusted is obtained at the same time.
The internal compression release valve portion 5B formed integrally with the bypass valve 5 can surely release the internal compression in the compression chamber 4 of the screw rotor when the bypass valve is opened, so that the internal compression is prevented from remaining. Although the electromagnetic clutch 10 is not activated, the starting torque for reactivating the supercharger is small, and even if the supercharger is frequently interrupted, the response to them is quick. No
The electromagnetic clutch itself can be used with a small capacity, and can be made smaller and lighter. As described above, unlike the conventional one, no piping for a bypass circuit is required, so that a complicated structure and space especially outside the supercharger can be omitted, resulting in a simple structure, which is inexpensive and economical.

Although the embodiments of the present invention have been described above, within the scope of the spirit of the present invention, the material and sectional shape of the male and female screw rotors, the spiral angle of rotor teeth, the material, the sectional shape and number, and the suction port. And the shape of the discharge port, the form of the electromagnetic clutch, the shapes of the bypass passage, the internal compression opening passage and the bypass valve and their positions, the shapes of the bypass valve portion and the internal compression opening valve portion in the bypass valve, and the actuation of the bypass valve. Form of actuator,
It goes without saying that an appropriate method can be adopted as the method of synchronizing the male and female rotors.

[0013]

As described above in detail, according to the present invention, the supercharging pressure can be surely supplied at the time of normal supercharging which requires a high supercharging pressure and the electromagnetic clutch OFF which does not require the supercharging. When the engine is over-boosted or the boost pressure is abnormally high, the time required to release the pressure is adjusted by the opening stroke of the bypass valve inside the casing of the screw type turbocharger. At the same time that the bypass pressure is released, the internal compression release valve portion formed integrally with the bypass valve can reliably release the internal compression in the compression chamber of the screw rotor when the bypass valve is opened. The electromagnetic clutch is no longer activated against the residual internal compression, the starting torque for the next restart of the turbocharger is small, and the turbocharger is frequently interrupted. Also, despite their responses are fast and can those be small space used of the electromagnetic clutch itself, more compact, lighter weight can be achieved. As described above, unlike the conventional one, no piping for a bypass circuit is required, so that a complicated structure and space especially outside the supercharger can be omitted, resulting in a simple structure, which is inexpensive and economical.

[Brief description of drawings]

FIG. 1 shows an embodiment of a screw type supercharger of the present invention and is an overall view of a partial cross section of the screw type supercharger.

FIG. 2 is an enlarged view of a main part of a bypass valve in one embodiment of a screw type supercharger of the present invention, and is a view for explaining an operating state.

FIG. 3 is a diagram showing a bypass circuit of a general supercharger in an internal combustion engine.

FIG. 4 is a view showing a conventional screw type supercharger (vacuum pump).

[Explanation of symbols]

 1 casing 2 screw type rotor (female) 3 screw type rotor (male) 4 compression chamber 5 bypass valve 5A bypass valve section 5B internal compression release valve section 6 bypass passage 7 internal compression release passageway 8 suction port 9 discharge port 10 electromagnetic clutch 11 Pulley 13 Actuator 14 Valve seat

Claims (2)

[Claims] Claim: What is claimed is: 1. A pair of screw type male and female rotors, which are operated by the connection of an electromagnetic clutch to mesh the air sucked from the suction port, are compressed in a compression chamber in the axial direction by a pair of screw type male and female rotors and the compressed air is supplied to the engine from the discharge port. In the screw type supercharger, a bypass passage accommodating a bypass valve that communicates the suction port side and the discharge port side when the supercharger is not operated is provided side by side with the compression chamber, and the bypass valve is opened. A screw type supercharger characterized in that the compression chamber and the bypass passage are communicated with each other. 2. An internal compression opening passage for communicating between the compression chamber and the bypass passage is bored near a valve seat of a bypass valve portion of the bypass valve, and the bypass valve opens and closes the internal compression opening passage. The screw type supercharger according to claim 1, wherein the compression opening valve portion is integrally formed.