JP7548821B2 - Two-stage reciprocating compressor - Google Patents

Description

The present invention relates to a two-stage reciprocating compressor.

A two-stage reciprocating compressor is known that compresses air in two stages to obtain high-pressure compressed air. The two-stage reciprocating compressor has a low-pressure cylinder and a high-pressure cylinder. In the two-stage reciprocating compressor, air compressed in the low-pressure cylinder is sent to the high-pressure cylinder and further compressed in the high-pressure cylinder. The compressed air compressed in the high-pressure cylinder is supplied to a pneumatic machine through a discharge port. When the two-stage reciprocating compressor is installed in a commercial vehicle, the compressed air discharged from the high-pressure cylinder head is supplied to, for example, a brake or an air suspension. A conventional two-stage reciprocating compressor is disclosed in JP 2013-040586 A.

Since compression heat is generated during the air compression process, the temperature of the cylinder and piston rises during operation of the reciprocating compressor. In addition, since the electric motor is driven by an applied current, Joule heat is generated by this applied current. This also causes the temperature of the electric motor to rise. For this reason, conventional reciprocating compressors are often equipped with a cooling fan. Two-stage reciprocating compressors equipped with a cooling fan are disclosed in JP 09-264253 A and JP 2016-070233 A.

JP 2013-040586 A Japanese Patent Application Publication No. 9-264253 JP 2016-070233 A

Further improvement in cooling effect is required in two-stage reciprocating compressors equipped with cooling fans.

One object of the present disclosure is to improve the cooling effect in a two-stage reciprocating compressor. Other objects of the present disclosure can be understood by reference to the entire description of the present specification.

A two-stage reciprocating compressor according to one aspect of the present invention comprises a rotary drive source housed in a case, an output shaft extending in the axial direction that outputs rotation from the rotary drive source and has one end protruding from an end face of the case, a low-pressure compression element that compresses air using the rotary drive force from the output shaft as a power source, an intercooler that cools the compressed air discharged from the low-pressure compression element, a high-pressure compression element that further compresses the compressed air cooled by the intercooler using the rotary drive force from the motor output shaft as a power source, and a blower fan connected to the output shaft and disposed between the end face of the housing and the intercooler in the axial direction.

In one aspect of the present invention, the case has a plurality of ribs extending in the axial direction on its outer surface.

In one aspect of the present invention, the case has a number of other ribs extending perpendicular to the axial direction.

The two-stage reciprocating compressor according to one aspect of the present invention further comprises a silencer that supplies the air to the low-pressure compression element.

A two-stage reciprocating compressor according to one aspect of the present invention further comprises covers for the case, the low-pressure compression element, the intercooler, the high-pressure compression element, and at least a portion of the blower fan.

One aspect of the present invention relates to an automobile. The automobile is equipped with the above-mentioned two-stage reciprocating compressor.

Embodiments of the present invention can improve the cooling effect in a two-stage reciprocating compressor.

FIG. 1 is a perspective view illustrating a two-stage reciprocating compressor according to an embodiment. FIG. 2 is a schematic side view of the two-stage reciprocating compressor of FIG. 1 . FIG. 3 is a cross-sectional view illustrating the two-stage reciprocating compressor of FIG. 2 taken along line AA. FIG. 4 is a perspective view illustrating a two-stage reciprocating compressor according to another embodiment. FIG. 4 is a schematic cross-sectional view of a two-stage reciprocating compressor according to another embodiment.

With reference to Figures 1 to 3, a two-stage reciprocating compressor 1 according to various embodiments of the present invention will be described. Figure 1 is a perspective view showing a two-stage reciprocating compressor 1 according to one embodiment of the present invention, Figure 2 is a schematic side view of the two-stage reciprocating compressor 1 of Figure 1, and Figure 3 is a schematic cross-sectional view showing a cross section of the two-stage reciprocating compressor 1 cut along line A-A of Figure 2. When referring to the up-down direction in this specification, the up-down direction shown in Figure 1 is used as the reference unless otherwise specified in the context. When referring to the front-rear direction in this specification, the front-rear direction shown in Figure 2 is used as the reference unless otherwise specified in the context. Figure 2 shows an axis C that coincides with the central axis of a crankshaft described later. The axis C extends in the front-rear direction. In this specification, the direction along the axis C is sometimes called the axial direction, and the direction extending perpendicular to the axis C from the axis C is sometimes called the radial direction.

As shown in Fig. 1, the two-stage reciprocating compressor 1 includes a housing 10. The housing 10 includes a motor case 11, a crankcase 12, a first cylinder 13a, and a second cylinder 13b. The first cylinder 13a and the second cylinder 13b are each provided above the crankcase 12. Four legs are attached to the underside of the housing 10 via supports 19. The two-stage reciprocating compressor 1 is installed in a desired installation location via the legs 18.

The outer surface of the motor case 11 is provided with a plurality of first ribs 11a extending along the axial direction and a second rib 11b extending along the vertical direction. The upper ends of the second ribs 11b are connected to the rear ends of the corresponding first ribs 11a. Some of the first ribs 11a extend from the rear end to the front end of the motor case 11, and the remaining portions extend forward from the rear end of the motor case 11 and are connected to the second ribs 11b midway.

The motor case 11 has an internal space penetrating the inside along the axis C. The motor case 11 has a generally hollow cylindrical shape. A motor 22 is disposed in the internal space of the motor case 11. The motor 22 has a stator coil 22a attached to the inner wall of the motor case 11, a rotor 22b assembled radially inside the stator coil 22a, and a motor rotating shaft 22c rotating together with the rotor 22b. The motor 22 may be provided with a rotation detection sensor that detects the rotation position of the rotor 22b. The through hole of the motor case 11 is closed at the rear end by the rear cap 23. As a result, the rear surface of the rear cap 23 becomes the rear end surface 11c of the motor case 11. A through hole is provided in the radial center of the rear cap 23 to connect the internal space of the motor case 11 to the external space. The motor rotating shaft 22c extends to the outside of the housing 10 through a through hole provided in the rear cap 23. The motor rotating shaft 22c is rotatably supported by the motor case 11 via a bearing.

A blower fan 24 is attached to the rear end of the motor shaft 22c, which protrudes rearward from the motor case 11. The blower fan 24 rotates together with the motor shaft 22c around the central axis C. The rotation of the blower fan 24 generates an airflow fi that flows from the axial rear of the blower fan 24 toward the fan, and an airflow fo that flows axially from the front of the blower fan 24 along the outer surface of the housing 10.

An internal space is formed in the crankcase 12, penetrating through the interior thereof along the axis C. The internal space of the crankcase 12 and the internal space of the motor case 11 are partitioned by a partition wall 20. The through hole provided in the crankcase 12 is closed at its front end by a front cap 21. The front cap 21 has a substantially disk-shaped cap body 21a and a dome 21b that protrudes forward from the radial center of the cap body 21a.

A crank mechanism is disposed in the internal space of the crankcase 12. The crank mechanism has a crankshaft 15. The crankshaft 15 extends along the central axis C inside the crankcase 12 and the motor case 11. The crankshaft 15 is supported at its front end by the front cap 21. The crankshaft 15 enters the motor case 11 from a through hole provided in the partition wall 20 and is supported on the inner peripheral surface of the hollow motor shaft 22c inside the motor case 11. The crankshaft 15 is attached to the motor shaft 22c so as to rotate around the central axis C together with the motor shaft 22c. As a result, the rotational driving force from the motor 22 is transmitted to the crankshaft 15 via the motor shaft 22c.

The crankshaft 15 has a first eccentric portion 15a and a second eccentric portion 15b provided axially rearward of the first eccentric portion 15a. The first eccentric portion 15a and the second eccentric portion 15b have a circular shape in a cross section perpendicular to the axis C. The center of the eccentric portion 15a is eccentric from the axis C. The first eccentric portion 15a is connected to a first piston 16a via a first connecting rod 14a. Similarly, the second eccentric portion 15b is connected to a second piston 16b via a second connecting rod 14b. The rotational motion of the crankshaft 15 is converted into a reciprocating motion of the first piston 16a by the first connecting rod 14a, and into a reciprocating motion of the second piston 16b by the second connecting rod 14b. In this manner, the first piston 16a reciprocates within the first cylinder 13a, and the second piston 16b reciprocates within the second cylinder 13a.

The first eccentric portion 15a and the second eccentric portion 15b have different phases. For example, the phase of the first eccentric portion 15a and the phase of the second eccentric portion 15b are shifted from each other by 180°. Due to this phase shift, when the first piston 16a is driven in a direction to compress the cylinder chamber of the first cylinder 13a, the second piston 16b is driven in a direction to expand the cylinder chamber of the second cylinder 13b. On the other hand, when the second piston 16b is driven in a direction to compress the cylinder chamber of the second cylinder 13b, the first piston 16a is driven in a direction to expand the cylinder chamber of the first cylinder 13a.

A first cylinder head 17a is provided at the tip of the first cylinder 13a, and a second cylinder head 17b is provided at the tip of the second cylinder 13b. The first cylinder head 17a has an intake port 27a for drawing air into its internal space, and an exhaust port 27b for discharging compressed air. The internal space of the first cylinder head 17a is divided into an intake chamber and a discharge chamber by a partition. Air that flows into the intake chamber from the outside of the first cylinder head 17a through the intake port 27a is drawn into the first cylinder 13a, compressed by the first piston 16a reciprocating in the cylinder 13a, and then discharged to the discharge chamber. This compressed air is introduced from the exhaust port 27b of the first cylinder head 17a through the piping 26a to the intercooler 25, cooled by the intercooler 25, and introduced into the second cylinder head 17b through the piping 26b. The second cylinder head 17b has an intake port 28a for sucking in compressed air from the pipe 26b, and an exhaust port (not shown) for discharging compressed air compressed in the second cylinder 13b in the second stage. The air flowing into the second cylinder head 17b through the intake port 28a is sucked into the second cylinder 13b, compressed in the second stage by the first piston 16b reciprocating in the cylinder 13b, and then discharged to the outside of the second cylinder head 17b through the exhaust port. The compressed air compressed in the second stage by the second cylinder 13b can be supplied to various pneumatic machines (not shown). The pneumatic machines include various devices that operate using compressed air. When the two-stage reciprocating compressor 1 is mounted on a commercial vehicle, the compressed air from the second cylinder 13b can be supplied to, for example, an air brake, an air suspension, and various other pneumatic machines mounted on the commercial vehicle.

In this way, in the two-stage reciprocating compressor 1, air introduced from the outside undergoes a first stage of compression in the first cylinder 13a, and a second stage of compression in the second cylinder 13b. In this way, the first cylinder 13a is a low-pressure cylinder, and the second cylinder 13b is a high-pressure cylinder. In this specification, the first cylinder 13a may be referred to as the low-pressure compression element, and the second cylinder 13b may be referred to as the high-pressure compression element. The low-pressure compression element may include the first piston 16a and the first cylinder head 17a. The high-pressure compression element may include the second piston 16b and the second cylinder head 17b.

3, the intercooler 25 is provided axially rearward of the blower fan 24. In other words, the blower fan 24 is provided between the intercooler 25 and the rear end face of the motor case 11. The intercooler 25 is attached to the motor case 11, for example, by bolts (not shown).

The intercooler 25 is connected to the exhaust port 27b of the first cylinder head 17a via a pipe 26a, and to the intake port 28a of the second cylinder head 17b via a pipe 26b. The intercooler 25 has a serpentine pipe connecting the pipe 26a and the pipe 26b, and a number of fins provided on the pipe. The pipe of the intercooler 25 is supplied with high-temperature compressed air compressed in the first cylinder 13a from the pipe 26a. As described above, an airflow fi flows with the rotation of the blower fan 24, and this airflow passes through the intercooler 25. Since this airflow fi flows along the outer surfaces of the pipes and fins of the intercooler 25, the compressed air passing through the inside of the intercooler 25 is cooled.

Next, the operation of the two-stage reciprocating compressor 1 will be described. When a current is applied to the stator coil 22a, the rotor 22b rotates relative to the stator coil 22a. At this time, the rotation of the rotor 22b is transmitted to the crankshaft 15 and the blower fan 24 via the motor rotating shaft 22c. The rotational motion of the crankshaft 15 is converted into the reciprocating motion of the first piston 16a by the first connecting rod 14a, and into the reciprocating motion of the second piston 16b by the second connecting rod 14b. Due to the reciprocating motion of the first piston 16a and the second piston 16b, the air introduced from the outside is compressed in the first cylinder 13a in the first stage, and compressed in the second cylinder 13b in the second stage. The air compressed in the first cylinder 13a is cooled by the intercooler 25 and then introduced into the second cylinder 13b. Cooling air is supplied to the intercooler 25 from the blower fan 24, which rotates by the rotational driving force from the motor 22.

Figure 4 is a perspective view showing a two-stage reciprocating compressor 1 according to another embodiment of the present invention. The two-stage reciprocating compressor 1 of Figure 4 differs from the two-stage reciprocating compressor 1 shown in Figure 1 in that it is provided with a cover 40. The cover 40 is a soundproof cover. The cover 40 may cover the entire circumference of the two-stage reciprocating compressor 1. In the illustrated embodiment, the legs 18 of the two-stage reciprocating compressor 1 are exposed from the cover 40 for convenience of mounting to a vehicle body. A through hole may be provided in a part of the cover 40 to connect the inside and the outside of the cover 40. The cover 40 is made of a material having a soundproofing function. The material of the cover 40 is, for example, felt, polyvinyl chloride, or other material having soundproofing properties. This cover 40 can suppress the leakage of sound generated from the two-stage reciprocating compressor 1 to the outside.

5 is a perspective view showing a two-stage reciprocating compressor 1 according to another embodiment of the present invention. The two-stage reciprocating compressor 1 of FIG. 5 differs from the two-stage reciprocating compressor 1 shown in FIG. 1 in that it includes a silencer 50. The silencer 50 is attached to the dome 21b of the front cover 21. The silencer 50 has, for example, a hollow cylindrical shape. The internal space of the silencer 50 is defined into a first chamber that takes in outside air from the intake port 50a, and a silencing chamber that is connected to the first chamber and takes in air from the first chamber. The intake port 50a may be provided at any position of the silencer 50. The silencer 50 may have a partitioned space other than the internal space, the first chamber, and the silencing chamber. The silencing chamber is connected to the intake port 27a of the first cylinder head 17a. When the motor 22 is driven, the suction chamber of the first cylinder head 17a becomes negative pressure, so that air is taken into the first chamber from outside the silencer 50. This air flows from the first chamber into the sound-absorbing chamber, where it expands and is silenced, thereby reducing the intake noise that occurs when outside air is drawn in.

The above-mentioned two-stage reciprocating compressor 1 can be mounted, for example, on a commercial vehicle. One aspect of the present invention is a vehicle equipped with the two-stage reciprocating compressor 1.

The effects of the above embodiment are described below. In one embodiment of the present invention, the blower fan 24 is provided between the rear end surface 11c of the motor case 11 and the intercooler 25 in the axial direction. This makes it easier for the cooling air generated by the blower fan 24 to pass through the intercooler 25, improving the cooling effect of the compressed air in the intercooler 25. In a conventional two-stage reciprocating compressor, the intercooler is provided between the rear end surface of the motor case and the blower fan in the axial direction. In the arrangement of this conventional two-stage reciprocating compressor, the cooling air sent from the blower fan to the intercooler collides with the rear end surface of the motor case, causing the airflow to become turbulent, and the cooling air from the blower fan does not sufficiently contribute to cooling the intercooler. In an embodiment of the present invention, the cooling effect is improved by changing the axial arrangement of the blower fan and the intercooler.

In the above embodiment, a plurality of first ribs 11a extending in the axial direction and a plurality of second ribs 11b extending in the vertical direction are provided on the outer surface of the motor case 11. When the two-stage reciprocating compressor 1 is in operation, Joule heat is generated by a current applied to the stator coil 22a, and the heat generated in the stator coil 22a is transferred to the motor case 11. Since the surface area of the outer surface of the motor case 11 is increased by the first ribs 11a and the second ribs 11b, the heat generated in the stator coil 22a can be efficiently dissipated into the atmosphere.
Furthermore, the first ribs 11a guide the cooling air from the blower fan 24 in the axial direction along the outer surface of the motor case 11. Therefore, the cooling air from the blower fan 24 flows between adjacent first ribs 11a, and this cooling air can further improve the heat dissipation efficiency.

The dimensions, materials, and arrangement of each component described in this specification are not limited to those explicitly described in the embodiments, and each component can be modified to have any dimensions, materials, and arrangement that can be included in the scope of the present invention. In addition, components not explicitly described in this specification can be added to the described embodiments, and some of the components described in each embodiment can be omitted.

Some of the modified examples are exemplified below. The motor case 11 and the crank case 12 may have an integrated one-piece structure. The motor case 11 and the crank case 12 may be configured as separate members. The two-stage reciprocating compressor 1 may be provided with a control circuit for controlling the motor 22.

Reference Signs List 1 Two-stage reciprocating compressor 10 Housing 11 Motor case 12 Crank case 13a First cylinder (low-pressure side cylinder)
13b Second cylinder (high pressure side cylinder)
Reference Signs List 14a First connecting rod 14b Second connecting rod 15 Crankshaft 15a First eccentric portion 15b Second eccentric portion 16a First piston 16b Second piston 17a First cylinder head 17b Second cylinder head 18 Leg portion 19 Support portion 21 Front cap 22 Motor 22a Stator coil 22b Rotor 22c Motor rotating shaft 23 Rear cap 24 Blower fan 25 Intercooler

Claims (6)

A rotary drive source housed in a case;
an output shaft that outputs rotation from the rotation drive source and extends in an axial direction and has one end protruding from an end face of the case;
a low-pressure compression element that compresses air using a rotational driving force from the output shaft as a power source;
an intercooler that cools the compressed air discharged from the low-pressure compression element;
a high-pressure compression element that further compresses the compressed air cooled by the intercooler using the rotational driving force from the output shaft as a power source;
a blower fan connected to the output shaft and disposed between the end surface of the case and the intercooler in the axial direction;
Equipped with
The intercooler is connected to the low-pressure compression element via a first pipe and to the high-pressure compression element via a second pipe, and has a serpentine cooler pipe connecting the first pipe and the second pipe.
Two-stage reciprocating compressor. The case has a plurality of ribs extending in the axial direction on an outer surface thereof , and a plurality of other ribs connected to some of the plurality of ribs .
2. The two-stage reciprocating compressor according to claim 1. The plurality of other ribs extend in a direction perpendicular to the axial direction.
3. A two-stage reciprocating compressor according to claim 2. a silencer for supplying the air to the low pressure compression element;
The two-stage reciprocating compressor according to any one of claims 1 to 3. The compressor further includes a cover that covers at least a portion of the case, the low-pressure compression element, the intercooler, the high-pressure compression element, and the blower fan.
The two-stage reciprocating compressor according to any one of claims 1 to 4. An automobile equipped with a two-stage reciprocating compressor according to any one of claims 1 to 5.

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