JPH08105387A - Air compressor device - Google Patents

Abstract

PURPOSE: To reduce the noise based on the gear contact of a gear device by providing an air passage to communicate the inside of a cylinder with the atmosphere, opening an air compressor device interposed in the middle thereof at the beginning of the suction stroke, and flowing out the residual compressed air in the cylinder into the atmosphere. CONSTITUTION: In an air compressor where a piston 24 is reciprocated by a crank shaft 16 rotated by a driving source through a driving gear 22, etc., a solenoid 56 of a valve device 50 is energized based on the signal of a crank angle sensor 62 when the piston 24 reaches the top dead center of the compression. An armature 54 is pulled upward from the position of rest against a valve spring 58 to open an air passage 48 by a valve member 52. The residual compressed air in the clearance space of a cylinder 14 flows out from the air passage 48 into the atmosphere through a suction passage 42 to reduce the counter torque applied to a driving gear 22 and mitigate the impulsive abutting between the gear faces of the driving gear 22 and a crank gear 66.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air compressor device, and more particularly to a vehicular air compressor device suitable as a source of compressed air widely used as a working medium for a brake booster for vehicles such as trucks. Is.

[0002]

2. Description of the Related Art Compressed air is widely used as a working medium for boosters for brakes and the like in conventional, relatively large trucks, and is usually linked to the crankshaft of an engine as a source of compressed air. A reciprocating air compressor device driven by the motor is used. The air compressor device includes a compressor crankshaft having a compressor drive gear that meshes with a crank gear fixed to a crankshaft of an engine via one or more intermediate gears or idler gears, and a crankshaft of the compressor. A piston that is reciprocally driven via a connecting rod,
It is composed of a cylinder slidably accommodating the piston and a cylinder head mounted on one open end of the cylinder. The cylinder head has a suction passage having one end communicating with the atmosphere and the other end communicating with the cylinder through a suction valve or a suction valve, and one end communicating with an air tank or a compressed air reservoir and the other end discharging. A discharge passage communicating with the cylinder via a valve or a delivery valve is provided.

As is well known in the art, in the air compressor device, during the lowering stroke of the piston, that is, the suction stroke, the suction valve opens to take in outside air from the suction passage into the cylinder, and then the piston rises. In the stroke, that is, the compression stroke, the air in the cylinder is pressurized, the discharge valve is automatically opened by the pressure of the compressed air, and the compressed air is pumped from the discharge passage to the air tank or the compressed air reservoir. .

During operation of the reciprocating air compressor device, when the piston ends the compression stroke and shifts to the intake stroke, the compressed air remaining in the clearance volume of the cylinder is set at a set pressure with which the compressed air reservoir is filled. Since the air is a high-pressure air that is substantially equal to the compressed air, the piston is pressed downward by the remaining compressed air from the moment the piston moves beyond the compression top dead center to the intake stroke. Therefore, the compressor drive gear fixed to the crankshaft of the compressor has a torque in the opposite direction to the drive torque in the compression stroke (hereinafter, referred to as opposite torque).
Is caused, and a tooth surface collision due to backlash occurs, that is, tooth flapping occurs between the meshing teeth of an idler gear that meshes with the compressor drive gear or a crank gear that is fixed to the crank shaft of the engine. Noise is generated. As an example, the noise due to the gear rattling has a stroke volume of 320 cc, a compression ratio of 15, and a rated rotation speed of 500 rpm.
In the case of the heavy-duty truck air compressor, the level is as high as 90 decibels, and it has been a problem to reduce the noise level.

[0005]

SUMMARY OF THE INVENTION The present invention effectively eliminates the noise generated due to the above gear rattling in a reciprocating air compressor device driven by a drive source such as a vehicle engine through a gear device. It is an object of the present invention to provide an air compressor device of this kind that has a structure that can be reduced, has a simple and reliable operation, and is excellent in durability.

[0006]

In order to achieve the above object, according to the present invention, a piston for pressurizing and sucking air sucked into a cylinder is rotated by a drive source such as a vehicle engine via a gear device. In an air compressor that is reciprocally driven by being connected to a crankshaft, an air passage capable of communicating the inside of the cylinder with the atmosphere,
A valve device installed in the same air passage to control the communication between the cylinder and the atmosphere, and the piston opens the valve device at the beginning of the intake stroke from the compression top dead center to the bottom dead center, thereby remaining compression in the cylinder. An air compressor device is provided, which is provided with a control device for causing air to flow from the air passage to the atmosphere.

It is preferable that the control device is configured to output a drive signal to the valve device at the beginning of the intake stroke of the piston based on a signal from a sensor that detects the rotation angle of the crankshaft.

An intake passage, one end of which is in communication with the atmosphere and the other end of which is in communication with the cylinder through an intake valve, is connected to one open end of the cylinder, and one end of which is connected to a compressed air reservoir. Further, it is preferable to mount a cylinder head having a discharge passage, the other end of which communicates with the cylinder via a discharge valve, and arrange the air passage in the cylinder head.

Further, one end of the air passage is communicated with the cylinder and the other end is communicated with the suction passage upstream of the suction valve, and the piston is at compression top dead center. It is preferable that the control device is configured to open the valve device immediately after the transition to the intake stroke beyond the above range, preferably within a range of 15 degrees from the top dead center in crank angle.

Further, the valve device has an armature connected to the valve member for opening and closing the air passage or formed integrally with the valve member, and a solenoid for controlling the opening and closing of the valve member via the armature. It is preferably a solenoid valve. Further, the air passage is formed in the cylinder head as an independent passage separate from the suction passage and the discharge passage, and the air passage is formed in a valve chamber formed adjacent to an opening end of the air passage on the cylinder side. The valve member of the valve device can be arranged.

[0011]

According to the present invention, immediately after the piston of the air compressor device exceeds the compression top dead center and shifts to the intake stroke,
Since the valve device is opened by the control device and the residual compressed air in the cylinder is discharged from the air passage to the atmosphere, the compressed air pressure that acts to push down the piston is rapidly reduced, and thus the compressor is operated through the piston. The opposite torque acting on the drive gear fixed to the crankshaft is greatly reduced as compared with the conventional similar device. Due to the large reduction of the counter torque acting on the drive gear, the shocking contact between the tooth surfaces of the same gear and the other gear meshing with the gear and the tooth flaking, that is, ratcheting, is effectively mitigated. .

[0012]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. First, in the first embodiment of the present invention shown in FIGS. 1 to 3, reference numeral 10 generally indicates an air compressor, which is located at an appropriate position of an engine (not shown) such as a truck. The crankcase 12 is equipped with bolts and the like, and the cylinder 14 has a lower end fitted into an upper end opening of the crankcase 12. A crankshaft 16 is housed in the crankcase 12, and both ends of the crankshaft 16 are rotatably supported by the crankcase 12 via bearings 18 and 20. A drive gear 22 is fixed to one end of the crankshaft 16 that projects outside the crankcase.

A piston 24 is slidably fitted in the cylinder 14, and the piston 24 is pivotally attached to a small end portion of a connecting rod 28 via a piston pin 26. Also, the large end of the connecting rod 28 is
It is pivotally attached to the crank pin portion 30 of the crank shaft 16. The cylinder head 32 is provided at the upper opening end of the cylinder 14.
Is mounted and fixed together with the cylinder 14 to the crankcase 12 by head bolts (not shown).

A discharge passage 36 is provided in the cylinder head 32, one end of which communicates with an air tank or compressed air reservoir 34 of the vehicle and the other end of which communicates with the cylinder 14, and the discharge passage 36 is adjacent to the cylinder 14. A plate-shaped discharge valve 40, which is normally biased in the closing direction by a valve spring 38, is interposed in the portion. A suction passage 42, one end of which communicates with the atmosphere and the other end of which communicates with the cylinder 14, is provided in the cylinder head 32.
The valve spring 4 is provided in a portion adjacent to the second cylinder 14.
4 is a plate-shaped intake valve that is normally biased in the closing direction by
6 is interposed.

Further, an L-shaped air passage 48, one end of which communicates with the cylinder 14 and the other end of which communicates with the suction passage 42 upstream of the suction valve 46, is provided in the cylinder head 32. A rod-shaped valve member 52 of the valve device, generally indicated at 50, in the bent portion of the passage 48.
Has been inserted. The valve device 50 may be integrally formed with the rod-shaped valve member 52 or may be separately formed from the rod-shaped valve member 52.
2, an armature 54 connected to the armature 54, a solenoid 56 surrounding the armature 54, and the armature 5 described above.
4 is a solenoid valve including a valve spring 58 that constantly urges the valve member 52 to the closed position shown in FIG. The solenoid valve 50 is controlled to be opened and closed by a controller or a control device 60, and a signal from a crank angle sensor 62 for detecting a rotation angle of the crankshaft 16, that is, a crank angle θ _c is input to the control device 60.

In the illustrated embodiment, the drive gear 22 meshes with a crank gear 66 which is fixed to the crankshaft 64 of the engine (only the centerline is shown). When the distance between the open center lines of the crankshaft 64 of the engine and the crankshaft 16 of the air compressor is large, both gears 2
It goes without saying that one or more appropriate number of idler gears are interposed between 2 and 66.

Above the suction valve 46, there is a general reference numeral 6
An unloader device shown by 8 is provided, and the unloader device 68 includes a hydraulic cylinder 70 formed in the cylinder head 32, a piston 72 fitted in the hydraulic cylinder 70, and the piston 72. A return spring 74 that always biases towards the rest position shown in FIG.
It consists of and. The hydraulic cylinder 70 is connected to a suitable hydraulic pressure source 78 via a hydraulic pressure control valve 76, and the hydraulic pressure control valve 76 outputs an output signal P _a of a pressure sensor 80 for detecting the compressed air pressure in the compressed air reservoir 34. Is controlled by the controller 60 which receives

In the above structure, when the vehicle engine as the drive source is operating, the rotation of the crankshaft 64 is transmitted to the crankshaft 16 of the air compressor 10 via the crank gear 66 and the drive gear 22. The rotation of the crankshaft 16 causes the piston 24 to reciprocally slide in the cylinder 14 via the connecting rod 28. In the descending stroke of the piston 24, that is, in the intake stroke, the intake valve 46 is opened due to the pressure difference between the atmospheric pressure and the negative pressure generated in the cylinder 14, and the outside air is introduced from the intake passage 42 into the cylinder 14.
Inhaled into. Subsequently, when the piston 24 rises and enters the compression stroke, the air in the cylinder 14 is compressed, and when the air pressure reaches the set pressure, the discharge valve 40 is opened and the compressed air that has been pressurized is discharged from the discharge passage 36. It is fed under pressure to an air tank or compressed air reservoir 34. In the compressed air storage source 34,
When compressed air of a predetermined pressure is filled, the controller 60 that received signals P _a of the pressure sensor 80 opens the hydraulic pressure control valve 76, the hydraulic cylinder of the unloader 68 to hydraulic oil from the hydraulic source 78 Supply to 70. The piston 72 compresses the return spring 74 by hydraulic pressure and descends, and the piston rod forcibly opens the intake valve 46. In this state, since the inside of the cylinder 14 is always in communication with the atmospheric pressure, the intake air is not compressed even when the piston 24 slides back and forth, and the air compressor 10 performs substantially no load operation.

When the piston 24 finishes the compression stroke and shifts from the top dead center to the suction stroke during the load operation of the air compressor 10, the compressed air remaining in the clearance volume of the cylinder 14 pushes down the piston 24, and the connecting rod 28 and An opposite torque acts on the drive gear 22 via the crankshaft 16. Therefore, in the conventional air compressor, the crank gear 6 meshing with the drive gear 22 is
Due to the backlash between the tooth flanks of 6 (or idler gear), the tooth flanks of both gears abut against each other in a shocking manner, and a significant noise is generated due to tooth flapping. FIG. 2 is a pressure-crank angle diagram in which the vertical axis represents the air pressure in the cylinder 14 and the horizontal axis represents the crankshaft θ _c . A solid curve P _{1 in the} figure indicates the in-cylinder pressure of the conventional compressor. When the piston 24 enters the compression stroke, the in-cylinder pressure increases as indicated by the line ab, the discharge valve 40 opens at the point b, and the compression top dead center TD is reached.
Compressed air is pumped to the compressed air storage source 34 up to C (crank angle O). Piston 2 over TDC
4 enters the descending stroke, the in-cylinder pressure decreases along the cd line, and the in-cylinder pressure P _c decreases to a level of the residual pressure slightly higher than the atmospheric pressure as shown by the line d-e. To do. FIG.
FIG. 3 is a torque-crank angle diagram in which the vertical axis represents the load torque T _q of the drive gear 22 and the horizontal axis represents the crank angle θ _c . The solid line T ₁ is the torque of the conventional air compressor as in FIG. Shows changes. As shown by the line a'-b 'in the figure (corresponding to the line a-b in FIG. 2), the positive load torque of the drive gear 22 increases until the point b'where the discharge of compressed air starts. During the discharge of the compressed air, since the compressed air is simply sent out and the pressurization is not performed, the load torque is rapidly reduced to the top dead center TDC. Subsequently, when the piston 24 exceeds the top dead center TDC, a negative torque, that is, an opposite torque, is applied to the drive gear 22 as indicated by the line c'-d 'in the figure due to the expansion of the residual compressed air described above. Since this counter torque is large, a large noise is generated due to the tooth striking.

On the other hand, in the above-described configuration of the present invention, when the piston 24 reaches the compression top dead center TDC, the controller or control device 60 supplies a drive output to the valve device 50 based on the signal of the crank angle sensor 62, The solenoid 56 is energized. The biasing of the solenoit 56 compresses the valve spring 58, pulling the armature 54 upward from the rest position of FIG. 1, and the valve member 52 opens the air passage 48. Therefore, the compressed air remaining in the clearance volume of the cylinder 14 flows out from the air passage 48 to the atmosphere via the suction passage 42, and the in-cylinder pressure P _c is as shown by the dotted line P ₂ in FIG. Rapidly reduce to. Corresponding to this rapid reduction of the cylinder pressure, the counter torque or negative torque acting on the drive gear 22 as shown by the dotted line T ₂ in FIG. The impact contact between the tooth surfaces of the working crank gear 66 (or idler gear) is extremely effectively alleviated, and in the case of an air compressor for a large truck having the same stroke volume, compression ratio and rated speed as above, 2 It was confirmed that a noise reduction effect of 3 to 3 decibels can be obtained.

The valve opening period of the valve device 50 may be open between the compression top dead center TDC and the bottom dead center BTC of the piston 24, in other words, just before the start of the compression stroke. As is clear from the diagrams of FIGS. 2 and 3, the reduction of the in-cylinder pressure depends on the individual air compressor 10
Of the air passage 48, the passage resistance of the air passage 48, the size of the gap volume (that is, the amount of residual compressed air), the compression ratio, and other factors, but the crank angle is generally changed after the compression top dead center TDC. Within 30 degrees, preferably within 15 degrees, it is sufficient, and thereafter only consumes the electric power of the solenoid 56, which adversely affects the durability of the solenoid 56. 2 and 3, the conditions of the in-cylinder pressure and the opposite torque may be examined to determine the effective valve opening period.

Next, FIG. 2 shows a second embodiment of the present invention. In this embodiment, an independent linear air passage 48 separate from the intake passage 42 and the discharge passage 36 is provided in the cylinder head 32, and the air passage 48 is provided in the cylinder 1.
It has a valve chamber 82 whose diameter is expanded to the 4 side.

Similar to the first embodiment, the valve device composed of an electromagnetic valve has a solenoid 56 housed in a valve housing 84.
And the armature 54 driven by the solenoid 56.
And a valve shaft 86 integrally formed with the armature 54 and loosely inserted in the air passage 48, and a disc-shaped member disposed in the lower end of the valve shaft 86 and housed in the valve chamber 82. Valve member 5
2 and a valve spring 58 that elastically biases the valve member 52 toward the illustrated closed position via the armature 54 and the valve shaft 86, and the air passage 48 includes the lower end outer peripheral wall of the valve housing 84. It directly communicates with the atmosphere through a plurality of ventilation holes 88 formed in the.

The operation mode of the valve device 50 in this embodiment is substantially the same as that of the first embodiment, and the piston 2
Immediately after 4 exceeds the compression top dead center TDC, the armature 54 is pulled down against the valve spring 58 by energizing the solenoid 56 for an appropriate period, and the valve member 52 is opened as shown by the dotted line in the figure. It When the valve member 52 is opened, the residual compressed air in the cylinder 14 passes through the air passage 48 and is rapidly discharged to the atmosphere from the vent hole 88 of the valve housing 84. Therefore, the teeth of the drive gear 22 and the crank gear 66 (or the idler gear) are toothed. Generation of noise due to hitting is effectively reduced. In addition, in this embodiment, since the air passage 48 is formed linearly, there is an advantage that the processing is easy and the manufacturing cost is low.

In the first and second embodiments described above, the valve device 50 is an electromagnetic valve whose opening / closing timing and opening time are the easiest to control.
A hydraulic responsive valve having an actuator of hydraulic cylinder device similar to that of No. 8 or a valve device having a pneumatic actuator having compressed air as a working medium may be appropriately substituted. Further, in the above embodiment, the air compressor 1
Although the configuration in which the discharge valve 40 and the suction valve 46 of 0 are formed as plate valves is illustrated, the present invention is widely applied to a reciprocating air compressor that uses a reed valve, a mushroom valve or the like as the discharge valve and the suction valve. Can be applied.

[0026]

As described above, in the air compressor device according to the present invention, the piston for pressurizing and sucking the air sucked into the cylinder is rotated by the drive source such as the vehicle engine via the gear device. In an air compressor that is reciprocally driven by being connected to a crankshaft, an air passage capable of communicating the inside of the cylinder with the atmosphere,
A valve device installed in the same air passage to control the communication between the cylinder and the atmosphere, and the piston opens the valve device at the beginning of the intake stroke from the compression top dead center to the bottom dead center, thereby remaining compression in the cylinder. A control device that allows air to flow from the air passage to the atmosphere is provided, and a structure that can effectively reduce noise due to gear ratcheting of the gear device that occurs during operation of the air compressor is simple and simple. There is an advantage that it is possible to provide an air compressor device that operates reliably and has excellent durability.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between in-cylinder pressure and crank angle of the air compressor device shown in FIG. 1 in comparison with a conventional compressor device of the same type.

FIG. 3 is a diagram showing a relationship between a torque acting on a drive gear of the air compressor device shown in FIG. 1 and a crank angle in comparison with a conventional compressor device of the same type.

FIG. 4 is a cross-sectional view of essential parts showing a second embodiment of the present invention.

[Explanation of symbols]

10 ... Air compressor, 12 ... Crank case, 14
... Cylinder, 16 ... Crankshaft, 22 ... Drive gear, 24
... Piston, 32 ... Cylinder head, 34 ... Compressed air reservoir, 36 ... Discharge passage, 40 ... Discharge valve, 42 ... Suction passage, 46 ... Suction valve, 48 ... Air passage, 50 ... Valve device, 6
0 ... Controller (control device), 62 ... Crank angle sensor, 66 ... Crank gear, 68 ... Unloader device.

Claims (7)

[Claims] 1. An air compressor in which a piston for pressurizing and sucking air sucked into a cylinder is reciprocally driven by being connected to a crankshaft rotated by a drive source such as a vehicle engine via a gear device. An air passage capable of communicating the inside of the cylinder with the atmosphere,
A valve device installed in the same air passage to control the communication between the cylinder and the atmosphere, and the piston opens the valve device at the beginning of the intake stroke from the compression top dead center to the bottom dead center, thereby remaining compression in the cylinder. An air compressor device, comprising: a control device that causes air to flow from the air passage to the atmosphere. 2. The control device is configured to output a drive signal to the valve device at the beginning of the intake stroke of the piston based on a signal from a sensor that detects the rotation angle of the crankshaft. The air compressor device according to claim 1. 3. An intake passage, one end of which is in communication with the atmosphere and the other end of which is in communication with the cylinder via an intake valve, and one end of which is in communication with the compressed air storage source, at one open end of the cylinder. 2. A cylinder head having a discharge passage, the other end of which communicates with the cylinder via a discharge valve, is mounted, and the air passage is arranged in the cylinder head. Air compressor device. 4. The air passage according to claim 3, wherein one end of the air passage is in communication with the cylinder and the other end is in communication with the intake passage on the upstream side of the intake valve. Air compressor device. 5. The control device is configured to open the valve device immediately after the piston has passed the compression top dead center and transitioned to the suction stroke, preferably within a range of 15 degrees from the top dead center in crank angle. The air compressor device according to claim 2, wherein 6. An electromagnetic system in which the valve device includes an armature that is connected to or integrally formed with a valve member that opens and closes the air passage, and a solenoid that controls opening and closing of the valve member via the armature. The air compressor device according to claim 1, wherein the air compressor device is a valve. 7. The valve chamber, wherein the air passage is formed in the cylinder head as an independent passage separate from the suction passage and the discharge passage, and is formed adjacent to an opening end of the air passage on the cylinder side. The air compressor device according to claim 3, wherein a valve member of the valve device is provided in the air compressor device.