Two-stage reciprocating compressor

Abstract

To improve the cooling effect in a two-stage reciprocating compressor.SOLUTION: A two-stage reciprocating compressor 1 comprises a motor housed in a motor case 11, a first cylinder 13a that outputs rotation from the motor and compresses air using as a power source the rotational driving force from a motor rotating shaft extending axially from an end face of the motor case 11, an intercooler 25 that cools the compressed air discharged from the first cylinder 13a, a second cylinder 13b that further compresses the compressed air cooled by the intercooler 25, and a blower fan 24 that is connected to the motor rotating shaft and is arranged between the motor case 11 and the intercooler 25. The outer surface of the motor case 11 is provided with a plurality of first ribs 11a extending in the axial direction and a plurality of second ribs 11b extending in a direction perpendicular to the axial direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a two-stage reciprocating compressor. [Background technology]

[0002] Two-stage reciprocating compressors are known that compress 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 via 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 air suspension. A conventional two-stage reciprocating compressor is disclosed in Japanese Patent Application Laid-Open No. 2013-040586.

[0003] Compression heat is generated during the air compression process, causing the temperatures of the cylinder and piston to rise during operation of a reciprocating compressor. Furthermore, because the electric motor is driven by an applied current, Joule heat is generated by this applied current, which 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 Japanese Patent Laid-Open Publication Nos. 9-264253 and 2016-070233. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-040586 [Patent Document 2] Japanese Patent Application Publication No. 9-264253 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-070233 Summary of the Invention [Problem to be solved by the invention]

[0005] There is a demand for further improvement in the cooling effect in two-stage reciprocating compressors equipped with cooling fans.

[0006] 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. [Means for solving the problem]

[0007] A two-stage reciprocating compressor according to one aspect of the present invention includes: a rotary drive source accommodated in a case; an output shaft extending in an 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 rotational 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 rotational drive force from the motor output shaft as a power source; and a blower fan connected to the output shaft and disposed axially between the end face of the housing and the intercooler.

[0008] In one aspect of the present invention, the case has a plurality of ribs on its outer surface extending in the axial direction.

[0009] In one aspect of the present invention, the case has a plurality of other ribs extending in a direction perpendicular to the axial direction.

[0010] The two-stage reciprocating compressor according to one aspect of the present invention further includes a silencer that supplies the air to the low-pressure compression element.

[0011] The two-stage reciprocating compressor according to one aspect of the present invention further includes a cover for at least a portion of the case, the low-pressure compression element, the intercooler, the high-pressure compression element, and the blower fan.

[0012] One aspect of the present invention relates to a vehicle, the vehicle including the two-stage reciprocating compressor described above. [Effects of the Invention]

[0013] Embodiments of the present invention can improve cooling effectiveness in a two-stage reciprocating compressor. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view schematically illustrating a two-stage reciprocating compressor according to an embodiment. [Figure 2] FIG. 2 is a schematic side view of the two-stage reciprocating compressor of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view schematically showing a cross section of the two-stage reciprocating compressor of FIG. 2 taken along line AA. [Figure 4] FIG. 10 is a perspective view schematically showing a two-stage reciprocating compressor according to another embodiment. [Figure 5] FIG. 2 is a schematic cross-sectional view of a two-stage reciprocating compressor according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] A two-stage reciprocating compressor 1 according to various embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view schematically illustrating the two-stage reciprocating compressor 1 according to one embodiment of the present invention. FIG. 2 is a schematic side view of the two-stage reciprocating compressor 1 of FIG. 1. FIG. 3 is a schematic cross-sectional view of the two-stage reciprocating compressor 1 taken along line AA of FIG. 2. When referring to the up-down direction in this specification, the up-down direction shown in FIG. 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 FIG. 2 is used as the reference unless otherwise specified in the context. FIG. 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 referred to as the axial direction, and the direction extending perpendicular to the axis C is sometimes referred to as the radial direction.

[0016] 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 lower surface of the housing 10 via supports 19. The two-stage reciprocating compressor 1 is installed at a desired installation location via the legs 18.

[0017] A plurality of first ribs 11a extending axially and second ribs 11b extending vertically are provided on the outer surface of the motor case 11. The upper ends of the second ribs 11b are connected to the rear ends of the corresponding first ribs 11a. Some of the plurality of first ribs 11a extend from the rear end to the front end of the motor case 11, while the remaining portions extend forward from the rear end of the motor case 11 and are connected to the second ribs 11b midway.

[0018] The motor case 11 has an internal space that penetrates the interior 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 mounted radially inside the stator coil 22a, and a motor shaft 22c that rotates together with the rotor 22b. The motor 22 may also include a rotation detection sensor that detects the rotational position of the rotor 22b. The through-hole of the motor case 11 is closed at its rear end by a rear cap 23. As a result, the rear surface of the rear cap 23 forms the rear end surface 11c of the motor case 11. A through-hole is provided in the radial center of the rear cap 23, connecting the internal space of the motor case 11 with the external space. The motor shaft 22c extends to the outside of the housing 10 through the through-hole provided in the rear cap 23. The motor rotary shaft 22c is rotatably supported by the motor case 11 via a bearing.

[0019] A blower fan 24 is attached to the rear end of the motor rotary shaft 22c that protrudes rearward from the motor case 11. The blower fan 24 rotates together with the motor rotary shaft 22c around the central axis C. The rotation of the blower fan 24 generates an airflow fi that flows from the rear of the blower fan 24 in the axial direction toward the fan, and an airflow fo that flows from the front of the blower fan 24 along the outer surface of the housing 10 in the axial direction.

[0020] 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 separated 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 main body 21a and a dome 21b that protrudes forward from the radial center of the cap main body 21a.

[0021] A crank mechanism is disposed in the internal space of the crankcase 12. This 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 through a through-hole formed in the partition wall 20 and is supported on the inner circumferential surface of a hollow motor rotating shaft 22c inside the motor case 11. The crankshaft 15 is attached to the motor rotating shaft 22c so as to rotate together with the motor rotating shaft 22c around the central axis C. As a result, the rotational driving force from the motor 22 is transmitted to the crankshaft 15 via the motor rotating shaft 22c.

[0022] The crankshaft 15 has a first eccentric portion 15a and a second eccentric portion 15b located 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. A first piston 16a is connected to the first eccentric portion 15a via a first connecting rod 14a. Similarly, a second piston 16b is connected to the second eccentric portion 15b via a second connecting rod 14b. 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. In this way, the first piston 16a reciprocates within the first cylinder 13a, and the second piston 16b reciprocates within the second cylinder 13a.

[0023] 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 by 180° from each other. Due to this phase shift, when the first piston 16a is driven in a direction that compresses the cylinder chamber of the first cylinder 13a, the second piston 16b is driven in a direction that expands the cylinder chamber of the second cylinder 13b. On the other hand, when the second piston 16b is driven in a direction that compresses the cylinder chamber of the second cylinder 13b, the first piston 16a is driven in a direction that expands the cylinder chamber of the first cylinder 13a.

[0024] A first cylinder head 17a is provided at the end of the first cylinder 13a, and a second cylinder head 17b is provided at the end 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 within the cylinder 13a, and then discharged into the discharge chamber. This compressed air is introduced from the exhaust port 27b of the first cylinder head 17a through a pipe 26a to the intercooler 25, cooled by the intercooler 25, and then introduced into the second cylinder head 17b through a pipe 26b. The second cylinder head 17b has an intake port 28a for drawing compressed air from the pipe 26b and an exhaust port (not shown) for discharging compressed air compressed in the second cylinder 13b. Air flowing into the second cylinder head 17b through the intake port 28a is drawn into the second cylinder 13b, compressed in a 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). Pneumatic machines include various devices operated by compressed air. When the two-stage reciprocating compressor 1 is installed in a commercial vehicle, the compressed air from the second cylinder 13b can be supplied to, for example, air brakes, air suspension, and various other pneumatic machines installed in the commercial vehicle.

[0025] As described above, 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. As described above, 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 a low-pressure compression element, and the second cylinder 13b may be referred to as a 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.

[0026] 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 by, for example, bolts (not shown).

[0027] The intercooler 25 is connected to the exhaust port 27b of the first cylinder head 17a via a pipe 26a, and is connected 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 attached to the pipe. High-temperature compressed air compressed in the first cylinder 13a is supplied to the pipe of the intercooler 25 from the pipe 26a. As described above, an airflow fi flows as the blower fan 24 rotates, and this airflow passes through the intercooler 25. This airflow fi flows along the outer surfaces of the pipe and fins of the intercooler 25, thereby cooling the compressed air passing through the intercooler 25.

[0028] 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 then converted 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, 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. 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 is rotated by the rotational driving force from the motor 22.

[0029] FIG. 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 FIG. 4 differs from the two-stage reciprocating compressor 1 shown in FIG. 1 in that it includes a cover 40. The cover 40 is a soundproof cover. The cover 40 may cover the entire periphery of the two-stage reciprocating compressor 1. In the illustrated embodiment, the legs 18 of the two-stage reciprocating compressor 1 are exposed through the cover 40 for ease of installation on a vehicle body. A through-hole connecting the inside and outside of the cover 40 may be provided in a portion of the cover 40. The cover 40 is made of a material having soundproofing properties. Examples of materials for the cover 40 include felt, polyvinyl chloride, or other soundproof materials. The cover 40 can prevent sound generated by the two-stage reciprocating compressor 1 from leaking to the outside.

[0030] FIG. 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 through an 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 on 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, a negative pressure is created in the suction chamber of the first cylinder head 17a, causing air to be drawn 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, reducing the intake noise that occurs when outside air is drawn in.

[0031] The above-described two-stage reciprocating compressor 1 can be mounted on, for example, a commercial vehicle. One embodiment of the present invention is a vehicle equipped with the two-stage reciprocating compressor 1.

[0032] The effects of the above-described embodiment are described below. In one embodiment of the present invention, the blower fan 24 is disposed axially between the rear end surface 11c of the motor case 11 and the intercooler 25. This allows the cooling air generated by the blower fan 24 to easily pass through the intercooler 25, thereby improving the cooling effect of the intercooler 25 on the compressed air. In a conventional two-stage reciprocating compressor, the intercooler is disposed axially between the rear end surface of the motor case and the blower fan. In this arrangement in a 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, disrupting the airflow, 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.

[0033] 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 an electric current applied to the stator coil 22a, and the heat generated in the stator coil 22a is transferred to the motor case 11. The first ribs 11a and the second ribs 11b increase the surface area of ​​the outer surface of the motor case 11, so that 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, which further improves the heat dissipation efficiency.

[0034] 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. Furthermore, 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.

[0035] Some of the modified examples are exemplified below. The motor case 11 and the crankcase 12 may have an integrated one-piece structure. The motor case 11 and the crankcase 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.

[0036] The inventions described in the claims of the original application of this application are as follows: [1] a rotary drive source housed in a case; an output shaft extending in the axial direction, which 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 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; A two-stage reciprocating compressor comprising: [2] The case has a plurality of ribs extending in the axial direction on its outer surface. [1] The two-stage reciprocating compressor according to [1]. [3] The case has a plurality of other ribs extending in a direction perpendicular to the axial direction. [2] The two-stage reciprocating compressor according to [2]. [4] a silencer for supplying the air to the low-pressure compression element; [1] to [3]. A two-stage reciprocating compressor according to any one of [1] to [3]. [5] 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; [1] to [4]. A two-stage reciprocating compressor according to any one of [1] to [4]. [6] [1] to [5]. A motor vehicle equipped with the two-stage reciprocating compressor according to any one of [1] to [5]. [Explanation of symbols]

[0037] 1 Two-stage reciprocating compressor 10. Housing 11 Motor case 12 Crankcase 13a No. 1 cylinder (low pressure side cylinder) 13b No. 2 cylinder (high pressure side cylinder) 14a No. 1 connecting rod 14b No. 2 connecting rod 15 crankshaft 15a 1st eccentric part 15b 2nd eccentric part 16a First piston 16b Second piston 17a No. 1 cylinder head 17b No. 2 cylinder head 18 Legs 19 Support part 21 Front cap 22 Motor 22a stator coil 22b rotor 22c Motor shaft 23 Rear cap 24 Blower fan 25 Intercooler

Claims

1. a rotary drive source housed in a case; an output shaft extending in the axial direction, the output shaft outputting rotation from the rotary drive source and having one end protruding from an end face of the case; a low-pressure compression element that compresses air using the 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 a plurality of first ribs extending in the axial direction and a plurality of second ribs extending in the up-down direction are provided on an outer surface of the case, the plurality of first ribs include a long rib extending from a rear end of the case to a front end of the case along the axial direction, the first ribs include a plurality of short ribs extending from a rear end of the case along the axial direction to a position just forward of a front end of the case, the plurality of short ribs are connected to upper ends of corresponding second ribs among the plurality of second ribs, the plurality of second ribs include a distal second rib disposed distally with respect to the blower fan, and a proximal second rib disposed closer to the blower fan than the distal second rib, the distal second rib is longer than the proximal second rib in the vertical direction; Each of the plurality of short ribs and the plurality of second ribs is configured such that a distal end thereof distal to the outer surface of the case exists on an imaginary reference plane that passes through a position spaced apart from the output shaft and extends along the up-down direction and the front-rear direction parallel to the axial direction. Two-stage reciprocating compressor.

2. 2. The two-stage reciprocating compressor of claim 1, further comprising a silencer supplying said air to said low-pressure compression element.

3. 3. The two-stage reciprocating compressor according to claim 1, further comprising 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.

4. A motor vehicle comprising the two-stage reciprocating compressor according to any one of claims 1 to 3.

Images