JP7519942B2 - compressor - Google Patents

Description

The present invention relates to a compressor that compresses air.

Patent Document 1 describes a "screw compressor" as the compressor. This "screw compressor" is composed of a speed change device that changes (increases) the speed of the rotational driving force input to the main shaft from a driving source such as an engine and transmits it to the compressor body, and the compressor body that is driven by the rotational driving force input via this speed change device. The compressor body houses a pair of male and female screw rotors that mesh and rotate in a cylinder formed in a casing.

Patent No. 5225660

Although there is no explicit mention in cited document 1 of detecting the rotation speed of the spindle, from a general standpoint, it can be said that the method uses a sensor such as a proximity sensor to detect a dog that is linked to the spindle.

To attach this dog to the main shaft, parts such as mounting screws and mounting brackets are required, which increases the number of components in the compressor.

Therefore, the objective of the present invention is to provide a compressor with a reduced number of components.

The present invention is a compressor comprising a main body case, a rotor disposed inside the main body case and rotating, an input shaft that applies a rotational force to the rotor and has a portion protruding from the main body case, a torque limiter that is provided on the portion of the input shaft that protrudes from the main body case and prevents a torque exceeding a predetermined value from being transmitted from the input shaft to the rotor, a rotation sensor that is provided to detect the rotation speed of the input shaft, and a dog portion that is attached to a portion that rotates together with the input shaft in order to detect the rotation speed with the rotation sensor. The torque limiter comprises a limiter mechanism that rotates idly when a torque exceeding the predetermined value is applied from the input shaft, a limiter case that covers the limiter mechanism, and a lid portion that is attached to the limiter case by bolts, the rotation sensor is provided in a position of the main body case close to the input shaft, and the dog portion is attached to the limiter case by the same bolt as the lid portion.

According to the present invention, the dog portion is attached to the limiter case with the same bolt as the torque limiter cover portion. Therefore, there is no need for a dedicated bolt to attach the dog portion to the part that rotates with the input shaft.

According to the present invention, since a dedicated bolt is not required for attaching the dog portion, the number of component parts can be reduced.

1 is a perspective view showing an overall configuration of a compressor according to an embodiment of the present invention; FIG. 4 is a right side view showing a main body case and the like of the compressor. 3 is a cross-sectional view taken along the line III-III of FIG. 2, showing the compression portion. FIG. 2 is a partially cutaway perspective view showing the structure of a torque limiter provided in the compressor.

Below, an embodiment of a compressor 1 according to the present invention will be described with reference to the drawings. For ease of explanation, the up-down direction and the front-rear direction will be described according to the directions shown in FIG. 1, etc.

As shown in FIG. 1, the compressor 1 of this embodiment includes a main body case 2, an intake section 3, an exhaust section 4, a pair of rotors 5, an input shaft 6, a torque limiter 7, a rotation sensor 8, and a dog section 9.

As shown in FIG. 2, the main body case 2 has a front case 2F that incorporates a speed change unit and a rear case 2B that incorporates a compression unit. The compression unit is a part that compresses the air taken in by the rotation of a pair of rotors 5. The main body case 2 is provided with an intake section 3 that takes in and sends air (outside air) inside for intake and exhaust, and an exhaust section 4 that exhausts the compressed air generated in the main body case 2 to an external use point. The rear case 2B has an intake port 21 that communicates with the intake section 3 on the side, and an exhaust section 4 that opens upward. The speed change unit changes the rotation of the input shaft 6 to a rotation speed suitable for rotating the pair of rotors 5 by large and small gears. In this embodiment, the speed is increased, but it can also be reduced. Furthermore, it is possible not to provide a speed change unit itself (no speed change). Lubricating oil is held in the main body case 2 to lubricate each of the gears. The main body case 2 of this embodiment has a bulge section 23 that protrudes forward adjacent to the part from which the input shaft 6 protrudes. The inside of the bulge 23 is a space, expanding the space in the main body case 2 that can hold the lubricating oil.

As shown in FIG. 3, the pair of rotors 5 are arranged in the compression chamber 24 formed inside the main body case 2 (rear case 2B). The pair of rotors 5 is composed of two rotors 51, 52 in a "male-female" relationship arranged in parallel in the axial direction as shown in the figure. Each rotor 51, 52 rotates around the axial direction. The configuration of each rotor is well known and will not be described in detail, but one of the pair of rotors 51 has a spiral recess 511 formed on the outer circumferential surface, and the other rotor 52 has a spiral protrusion 521 formed on the outer circumferential surface. Although the illustration is simplified, both rotors 51 and 52 rotate with the protrusion 521 of the other rotor 52 fitting into the recess 511 of the rotor 51. As shown in FIG. 3, the rotational force supplied from the transmission unit is input to one rotor 51 from a rotor input shaft 512, which is a part of one rotor 51, and is also input to the other rotor 52 by transmission gears 513, 522 that are provided on each rotor 51, 52 and mesh with each other. At this time, the one rotor 51 and the other rotor 52 rotate in opposite directions. During rotation, a small gap is maintained between the recessed portion 511 and the protruding portion 521. By rotating the pair of rotors 5, air (outside air) taken in from the intake portion 3 is compressed between the recessed portion and the protruding portion, and the compressed air can be taken out from the exhaust portion 4. For example, in the case of a powder transport vehicle, the taken out compressed air is supplied to a shipping box, and the powder in the shipping box is fluidized by the air flow, so that the powder can be taken out of the shipping box.

The input shaft 6 is a shaft that provides a rotational force to the pair of rotors 5, and a part of the shaft protrudes from the main body case 2. The input shaft 6 is connected to a power supply source. When the compressor 1 is mounted on a vehicle, the input shaft 6 is connected to a power supply device such as a PTO provided on the vehicle side. The input shaft 6 in this embodiment is divided into a first shaft 61 located at the front (upstream side based on the transmission direction of the rotational force) and a second shaft 62 located at the rear (downstream side based on the transmission direction of the rotational force) by the torque limiter 7 being interposed. As shown in FIG. 4, the first shaft 61 and the second shaft 62 are arranged to overlap on the same linear axis. The first shaft 61 is connected to the power supply source via a flange portion 611 provided at the front end and rotating together.

The torque limiter 7 is provided on the part of the input shaft 6 that protrudes from the main body case 2 (specifically, between the first shaft 61 and the second shaft 62). The torque limiter 7 rotates around the axis of the input shaft 6. The torque limiter 7 prevents the pair of rotors 5 and the gears of the transmission unit from being damaged by torque exceeding a predetermined value being transmitted from the input shaft 6 to the pair of rotors 5. The torque limiter 7 includes a limiter mechanism 71 that rotates idly when torque exceeding the predetermined value is applied from the input shaft 6, a limiter case 72 that covers the limiter mechanism 71, a lid portion 73 attached to the limiter case 72, and a plurality of bolts 74 to 74 for fixing the lid portion 73 to the limiter case 72. The limiter case 72 is a cylindrical part that is concentric with the second shaft 62 and is formed by enlarging the diameter of the end of the second shaft 62 of the input shaft 6. In this embodiment, as shown in FIG. 4, the limiter case 72 is formed integrally with the second shaft 62.

The limiter mechanism 71 switches between transmission and disconnection of torque within the input shaft 6. Specifically, the limiter mechanism 71 is interposed between the rear end of the first shaft 61 and the front end of the second shaft 62 based on the transmission direction of the rotational force. In the limiter mechanism 71, the rear end surface 7111 of the rotating plate 711 expanded radially outward from the first shaft 61 and the inner peripheral surface 721 facing forward of the limiter case 72 are pressed and abutted by the force of the abutment spring 712. When the torque applied to the limiter mechanism 71 is equal to or less than a predetermined torque set in advance, the surface of the rotating plate 711 of the first shaft 61 and the axial inner peripheral surface of the limiter case 72 are interlocked by frictional force without shifting in the circumferential direction, and the rotational force is transmitted from the first shaft 61 to the second shaft 62. On the other hand, when the torque applied to the limiter mechanism 71 exceeds a preset torque, a circumferential shift occurs between the surface of the rotating plate 711 of the first shaft 61 and the axial inner surface of the limiter case 72, causing the limiter mechanism to rotate freely. This rotation prevents torque exceeding a preset value from being transmitted from the first shaft 61 to the second shaft 62. This prevents torque exceeding a preset value from being transmitted from the second shaft 62 to the pair of rotors 5.

The lid portion 73 is a generally circular ring shape through which the first shaft 61 penetrates in the thickness direction, and covers the axial end face (front end face) of the limiter case 72. The lid portion 73 is fixed by a plurality of bolts 74-74 (specifically, eight bolts) that are inserted from the lid portion 73 side toward the limiter case 72. Each bolt 74 is a hexagon socket bolt. The direction in which each bolt 74 extends is along the axial direction of the input shaft 6. Note that the direction in which the bolts 74 extend is not limited to this, and for example, when the lid portion 73 covers the outer peripheral surface of the limiter case 72, the bolts 74 may extend along the radial direction of the limiter case 72.

The lid 73 has a plurality of lid through holes 731-731 that penetrate the thickness direction at the same radial position and at regular intervals (constant angle) in the circumferential direction to allow the passage of the plurality of bolts 74-74. The end face of the limiter case 72 has screw holes 722 into which the plurality of bolts 74-74 are screwed at positions corresponding to the lid through holes 731. In this embodiment, the screw holes 722 are bottomed holes. However, this is not limited to this, and for example, a through hole without a thread may be formed in the limiter case 72, and the lid 73 may be fixed to the limiter case 72 by a combination of a bolt and a nut. By fixing the lid 73 to the limiter case 72, the limiter mechanism 71 is stored between the limiter case 72 and the lid 73 in a functional state.

The rotation sensor 8 is provided to detect the rotation speed of the input shaft 6. The rotation sensor 8 is provided in a position close to the input shaft 6 of the main body case 2 (specifically, in a position radially away from the input shaft 6). In this embodiment, as shown in FIG. 1, the rotation sensor 8 is provided on a bracket 25 that extends from the main body case 2 so as to face the outer circumferential surface of the limiter case 72. As the rotation sensor 8, for example, a general-purpose proximity sensor that performs detection using a change in magnetic flux when a detection target approaches a generated magnetic field can be used, but it is not limited to this, and various types of sensors can be used. The rotation speed of the input shaft 6 can be detected using the detection result of this rotation sensor 8.

The dog portion 9 is attached to a portion that rotates together with the input shaft 6 in order to detect the number of revolutions with the rotation sensor 8. The dog portion 9 is formed by bending a plate-shaped body (specifically, a steel plate). Depending on the type of the rotation sensor 8, the dog portion 9 is formed of a material or surface properties that the rotation sensor 8 can detect. In this embodiment, a steel plate, which is a magnetic material, is used. The dog portion 9 is integrally provided with a lid mounting portion 91 that is in the shape of an annular plate and multiple (specifically, six) protruding portions 92-92 that protrude from the lid mounting portion 91. In this embodiment, the protruding portions 92-92 are formed integrally with the lid mounting portion 91 and extend radially outward from the outer periphery of the lid mounting portion 91. The lid mounting portion 91 is attached so as to abut against the lid portion 73. The lid mounting portion 91 is provided with multiple dog portion through holes 911-911 that penetrate in the thickness direction at the same radial position and at regular intervals (constant angles) in the circumferential direction. Each dog through hole 911 is provided at a position corresponding to each lid through hole 731 in the lid 73.

The multiple protrusions 92-92 are provided at regular intervals (at regular angles) around the lid mounting portion 91. Each protrusion 92 is rectangular with an R-shaped tip. Each protrusion 92 is formed by extending the lid mounting portion 91 in the radial outward direction, and then bending the tip 921 at a right angle. When the dog portion 9 is attached to the lid 73, the tip 921 is disposed parallel to the outer circumferential surface at a position at a constant radial distance from the outer circumferential surface of the cylindrical limiter case 72. When the torque limiter 7 rotates together with the input shaft 6, the tip 921 moves (rotates) so as to pass through the detection range of the rotation sensor 8. Since the multiple tips 921-921 are positioned at regular intervals around the circumferential direction, the rotation speed of the torque limiter 7 and the input shaft 6 can be derived based on the pulses related to the detection of the multiple tips 921-921 by the rotation sensor 8.

The dog portion 9 configured in this manner is attached to the limiter case 72 with the same bolts 74 as the lid portion 73. In other words, each bolt 74 inserted from the lid portion 73 side toward the limiter case 72 passes through each dog portion through-hole 911 and the lid portion through-hole 731 of the lid portion attachment portion 91 of the dog portion 9, and is screwed into the screw hole 722 in the limiter case 72, thereby fastening them together.

In this manner, in this embodiment, the dog portion 9 is attached (fastened together) to the limiter case 72 with the same bolt 74 as the lid portion 73 of the torque limiter 7, so there is no need for a dedicated bolt to attach the dog portion 9 to a portion that rotates together with the input shaft 6. Therefore, in the compressor 1 of this embodiment, the number of components can be reduced accordingly. For this reason, it is suitable for use in vehicle-mounted compressors where weight reduction is required, for example.

Specifically, six protrusions 92-92 are provided. On the other hand, eight dog portion through holes 911-911 are provided corresponding to the multiple bolts 74-74. In other words, in this embodiment, the number of protrusions 92-92 and the number of dog portion through holes 911-911 are not the same. And, there are more dog portion through holes 911-911 than protrusions 92-92. With this number, the lid portion 73 and the lid portion attachment portion 91 can be reliably attached to the limiter case 72, and the protrusions 92-92 can be reliably detected by the rotation sensor 8.

The above describes an embodiment of the present invention by way of example, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, the compressor 1 in the above embodiment has a pair of rotors 5 (rotors 51, 52). However, the rotor 5 is not limited to this configuration and may be composed of a single shaft. In this case, the air (outside air) taken in from the intake section 3 is compressed as the single rotor 5 rotates.

1...Compressor, 2...Main body case, 3...Intake section, 4...Exhaust section, 5...Rotor, 6...Input shaft, 7...Torque limiter, 8...Rotation sensor, 9...Dog section, 2F...Front case, 2B...Rear case, 23...Bulge section, 24...Compression chamber, 25...Bracket, 51...One rotor, 52...Other rotor, 61...First shaft, 62...Second shaft, 71...Limiter mechanism, 72...Limiter case, 73...Cover section, 74...Bolster bolt, 91...lid attachment part, 92...protrusion, 511...recess, 512...rotor input shaft, 513...transmission gear, 521...protrusion, 522...transmission gear, 611...flange part, 711...rotating plate, 712...contact spring, 721...inner surface facing forward of limiter case, 722...screw hole, 731...each lid through hole, 731...lid through hole, 911...dog through hole, 921...tip, 7111...rear end surface of rotating plate

Claims (1)

The main body case,
a rotor disposed inside the main body case and rotating;
an input shaft that applies a rotational force to the rotor and has a portion protruding from the main body case;
a torque limiter provided on a portion of the input shaft protruding from the main body case, the torque limiter preventing a torque exceeding a predetermined value from being transmitted from the input shaft to the rotor;
a rotation sensor provided for detecting a rotation speed of the input shaft;
a dog portion attached to a portion rotating together with the input shaft in order to detect the rotation speed by the rotation sensor,
the torque limiter includes a limiter mechanism that rotates idly when torque exceeding the predetermined value is applied from the input shaft, a limiter case that covers the limiter mechanism, and a lid portion that is attached to the limiter case by bolts,
the rotation sensor is provided in the main body case at a position adjacent to the input shaft,
The dog portion is attached to the limiter case by a bolt common to the cover portion.