JP7523982B2 - Fluid machinery, rotation information calculation method, and construction machinery - Google Patents

Description

The present invention relates to a fluid machine, a rotation information calculation method, and a construction machine.

An example of a fluid machine is a hydraulic motor used for traveling construction machinery such as a hydraulic excavator. A hydraulic motor has a housing, a shaft supported rotatably within the housing, a cylinder block fitted and fixed to the outer circumferential surface of the shaft and having multiple cylinder chambers aligned in the direction of rotation, pistons housed in each cylinder chamber and movable along the direction of the rotation axis, and a swash plate and a valve plate housed within the housing and positioned on either side of the cylinder block in the direction of the rotation axis.

The pistons have ends that protrude toward the swash plate and are connected to the swash plate via shoes that slide against the swash plate. Each cylinder chamber communicates with a supply port and a discharge port of the housing via a valve plate. The valve plate has a supply port and a discharge port that communicate the cylinder chamber with the supply port and the discharge port.
Hydraulic oil is supplied to the cylinder chamber through the supply port and the valve plate, and the pressure of the hydraulic oil presses the piston against the swash plate. At this time, the shoe slides against the swash plate, and the reaction force of the force of the piston pressing the swash plate is converted into a force in the rotation direction. When the cylinder block and the piston rotate together, the piston repeats sliding movement (piston movement) within the cylinder chamber. At this time, the spatial volume within the cylinder chamber changes, and the hydraulic oil is discharged from the discharge port of the housing.

Utility Model Publication No. 63-120550

However, fluid machines such as hydraulic motors use fluid to obtain rotational force, so an external rotation detection device is required to obtain rotation information about the shaft (cylinder block). This can lead to a complex structure for the fluid machine.

The present invention provides a fluid machine, a method for calculating rotational information, and a construction machine that can acquire rotational information at low cost.

A fluid machine according to one aspect of the present invention includes a housing, a cylinder block accommodated within the housing so as to be rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port connected to the cylinder chamber, a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis, a plurality of supply and discharge ports connected to the cylinder ports being arranged side by side around the rotation axis, and a detection hole formed between adjacent supply and discharge ports around the rotation axis and connected to the cylinder port, and a pressure extraction unit that extracts the pressure of the fluid flowing into the detection hole.

With this configuration, the fluid in the cylinder port flows into the detection hole. As the cylinder block rotates relative to the valve plate in which the detection hole is formed, the detection hole and the cylinder port are connected and repeatedly open and closed. This causes the pressure of the fluid flowing into the detection hole to pulsate. The pressure waveform of the fluid caused by this pulsation is extracted via the pressure extraction section, and by detecting this extracted pressure waveform, rotation information such as the rotation speed and rotation angle of the cylinder block can be obtained. In addition, since no external rotation detection equipment is required, the structure of the fluid machine can be simplified.

The above configuration may include a pressure detection unit attached to the pressure extraction unit to detect the pressure of the fluid.

In the above configuration, the cylinder chamber may include a piston that is reciprocally movable along the rotation axis, and the detection hole may be formed at least at one of the top dead center position and the bottom dead center position of the piston in the valve plate.

In the above configuration, the housing may have an extension hole that is connected to the detection hole, and the pressure extraction section may extract the pressure of the detection hole through the extension hole.

In the above configuration, the extension holes may be formed in a straight line.

In the above configuration, the housing may be a rear flange having an intake and exhaust port through which the fluid is supplied and exhausted and which communicates with the supply and exhaust port.

In the above configuration, the valve plate may include a piston storage recess formed on one surface of the housing at the location where the detection hole is formed, and a blocking piston stored in the piston storage recess so as to block the opening of the piston storage recess and having a piston hole communicating with the detection hole.

The above configuration may include a seal portion that prevents the fluid from leaking between the inner surface of the piston storage recess and the outer surface of the blocking piston.

The above configuration may include a calculation unit that calculates the rotation speed of the cylinder block based on the detection result of the pressure detection unit.

In the above configuration, the detection hole has at least a first detection hole and a second detection hole, the pressure detection unit has a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal, and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal, and the first detection hole and the second detection hole may be formed so that there is a phase difference between the output signal of the first pressure detection unit and the output signal of the second pressure detection unit.

In the above configuration, the housing has a first extension hole that communicates with the first detection hole and a second extension hole that communicates with the second detection hole, the first pressure detection unit is provided on the opposite side of the first extension hole to the first detection hole, and the second pressure detection unit is provided on the opposite side of the second extension hole to the second detection hole.

In the above configuration, the phase difference may be any value between 10° and 170°, or between 190° and 350°.

In the above configuration, the phase difference may be 90° or 270°.

The above configuration may include a calculation unit that calculates the rotation direction of the cylinder block based on the output signal of the first pressure detection unit and the output signal of the second pressure detection unit.

In the above configuration, the calculation unit may have a count calculation unit that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit and calculates the rotation angle of the cylinder block based on the count value.

In the above configuration, the calculation unit may have a reset unit that resets the count value of the count calculation unit when the rotation angle of the cylinder block reaches a certain angle.

In the above configuration, the calculation unit may have a timer that measures the time for which the pulses are counted.

A rotation information calculation method according to another aspect of the present invention includes a housing, a cylinder block that is rotatably accommodated in the housing around a rotation axis and has a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that is connected to the cylinder chamber, a valve plate that is disposed between the housing and the cylinder block in the direction of the rotation axis and has a plurality of supply and discharge ports that are connected to the cylinder ports and are formed in a line around the rotation axis, and has a first detection hole and a second detection hole that are formed between adjacent supply and discharge ports around the rotation axis and are connected to the cylinder port, and a valve plate that detects the flow of the fluid that flows into the first detection hole. A method for calculating rotational information of a fluid machine, comprising: a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal; a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal; and a calculation unit that calculates the rotational direction of the cylinder block based on the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, wherein the calculation unit has an order detection process that detects the order of rise of the pulses of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, and a rotational direction determination process that determines the rotational direction of the cylinder block based on the order detected in the order detection process.

By using this method, the output signal of the first pressure detection unit and the output signal of the second pressure detection unit can be used to easily determine the direction of rotation as rotation information.

A rotation information calculation method according to another aspect of the present invention includes a housing, a cylinder block that is accommodated in the housing so as to be rotatable about a rotation axis and has a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that is connected to the cylinder chamber, a valve plate that is disposed between the housing and the cylinder block in the direction of the rotation axis and has a plurality of supply and discharge ports that are connected to the cylinder ports and are formed in a line around the rotation axis, and has a first detection hole and a second detection hole that are formed between adjacent supply and discharge ports around the rotation axis and are connected to the cylinder port, and a pressure sensor that detects the pressure of the fluid flowing into the first detection hole. A method for calculating rotation information of a fluid machine including a first pressure detection unit that outputs a detection result as a signal, a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal, and a calculation unit that calculates the rotation direction of the cylinder block based on the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, the calculation unit having a counting step that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit, and a rotation angle calculation step that calculates the rotation angle of the cylinder block based on the count value by the counting step.

By using this method, the rotation angle can be easily calculated as rotation information by using the output signal of the first pressure detection unit and the output signal of the second pressure detection unit.

A rotation information calculation method according to another aspect of the present invention includes a housing, a cylinder block that is rotatably accommodated within the housing around a rotation axis and has a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that is connected to the cylinder chamber, a valve plate that is disposed between the housing and the cylinder block in the direction of the rotation axis, and has a plurality of supply and discharge ports that are connected to the cylinder ports and are formed in a line around the rotation axis, and has a first detection hole and a second detection hole that are formed between adjacent supply and discharge ports around the rotation axis and are connected to the cylinder port, a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal, and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal, and A method for calculating rotation information of a fluid machine, comprising: a calculation unit that calculates the rotation direction of the cylinder block based on the output signal of the first pressure detection unit and the output signal of the second pressure detection unit; a count calculation unit that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit and calculates the rotation angle of the cylinder block based on the count value; and a timer that measures the time for counting the pulses, wherein the calculation unit has a frequency calculation step of calculating the frequency of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit; and a rotation speed calculation step of calculating the rotation speed of the cylinder block based on a voltage value generated by FV converting the frequency calculated by the frequency calculation step.

By using this method, the rotation speed as rotation information can be easily calculated using the output signal of the first pressure detection unit and the output signal of the second pressure detection unit.

A rotation information calculation method according to another aspect of the present invention includes a housing, a cylinder block that is rotatably accommodated within the housing around a rotation axis and has a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that is connected to the cylinder chamber, a valve plate that is disposed between the housing and the cylinder block in the direction of the rotation axis, and has a plurality of supply and discharge ports that are connected to the cylinder ports and are formed in a line around the rotation axis, and has a first detection hole and a second detection hole that are formed between adjacent supply and discharge ports around the rotation axis and are connected to the cylinder ports, a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal, and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal, A method for calculating rotation information of a fluid machine, comprising: a calculation unit that calculates the rotation direction of the cylinder block based on the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, the calculation unit counting pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit and calculating the rotation angle of the cylinder block based on the count value; and a timer that measures the time for counting the pulses, the calculation unit having a counting step that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit, and a rotation speed calculation step that calculates the rotation speed of the cylinder block based on the count value of the counting step within a certain period of time.

By using this method, the rotation speed as rotation information can be easily calculated using the output signal of the first pressure detection unit and the output signal of the second pressure detection unit.

A rotation information calculation method according to another aspect of the present invention includes a housing, a cylinder block that is rotatably accommodated within the housing around a rotation axis and has a cylinder chamber through which a fluid is supplied and discharged, and a cylinder port that is connected to the cylinder chamber, a valve plate that is disposed between the housing and the cylinder block in the direction of the rotation axis, and has a plurality of supply and discharge ports that are connected to the cylinder ports and are formed in a line around the rotation axis, and has a first detection hole and a second detection hole that are formed between the supply and discharge ports that are adjacent to each other around the rotation axis and that are connected to the cylinder port, a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal, a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal, and a valve plate that detects the pressure of the fluid flowing into the first detection hole and the second detection hole as a signal. A method for calculating rotation information of a fluid machine, comprising: a calculation unit that calculates the rotation direction of the cylinder block based on the output signal of the force detection unit and the output signal of the second pressure detection unit, the calculation unit counting pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit, and calculating the rotation angle of the cylinder block based on the count value; and a timer that measures the time for counting the pulses, the calculation unit having a counting step that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit, and a rotation speed calculation step that calculates the rotation speed of the cylinder block based on the time required to reach a certain count value in the counting step.

By using this method, the rotation speed as rotation information can be easily calculated using the output signal of the first pressure detection unit and the output signal of the second pressure detection unit.

A construction machine according to another aspect of the present invention includes a fluid machine and a vehicle body on which the fluid machine is mounted and driven by the fluid machine. The fluid machine includes a housing, a cylinder block that is rotatably accommodated in the housing around a rotation axis and has a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber, a valve plate that is disposed between the housing and the cylinder block in the direction of the rotation axis, has a plurality of supply and discharge ports that communicate with the cylinder ports and are formed in a line around the rotation axis, and has a detection hole that is formed between the supply and discharge ports that are adjacent to each other around the rotation axis and communicates with the cylinder port, and a pressure extraction unit that extracts the pressure of the fluid that flows into the detection hole.

This configuration makes it possible to provide a construction machine that is capable of acquiring cylinder block rotation information with a simple structure.

The above-mentioned fluid machinery, rotation information calculation method, and construction machinery can obtain rotation information of the cylinder block with a simple structure.

1 is a schematic configuration diagram of a construction machine according to an embodiment of the present invention. 1 is a configuration diagram showing a hydraulic motor according to a first embodiment of the present invention, with a part cut away; FIG. 2 is a plan view of a valve plate according to the first embodiment of the present invention. 4 is a graph showing an A-phase pressure waveform and a B-phase pressure waveform in the first embodiment of the present invention. 1 is a schematic configuration diagram of a construction machine according to a first embodiment of the present invention, viewed from above; FIG. 11 is an enlarged cross-sectional view of a portion of a valve plate corresponding to a bottom dead center detection hole in a second embodiment of the present invention.

Next, an embodiment of the present invention will be described with reference to the drawings.

<Construction machinery>
FIG. 1 is a schematic configuration diagram of a construction machine 100.
1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a revolving body 101, a running body 102 provided below the revolving body 101, and a hydraulic motor (an example of a fluid machine in the claims) 1 that drives the revolving body 101 and the running body 102.

The rotating body 101 rotates above the running body 102 by the hydraulic motor 1. The rotating body 101 includes a cab 103 that supports an operator riding on the rotating body 101, a boom 104 having one end connected to the cab 103, an arm 105 having one end connected to the other end of the boom 104, and a bucket 106 connected to the other end of the arm 105. The boom 104 swings relative to the cab 103. The arm 105 swings relative to the boom 104. The bucket 106 swings relative to the arm 105.

[First embodiment]
<Hydraulic motor>
FIG. 2 is a configuration diagram showing the hydraulic motor 1 with a part cut away.
2, the hydraulic motor 1 mainly comprises a casing (an example of a housing in the claims) 2, a cylinder block 3 rotatably provided within the casing 2 about a rotation axis C, a valve plate 4 provided between the casing 2 and the cylinder block 3 in the direction of the rotation axis C, and a pressure sensor (an example of a pressure detection section in the claims) 5 provided on the outer surface 2a of the casing 2. In the hydraulic motor 1, the cylinder block 3 is rotated by hydraulic oil as a fluid, and the rotation of the cylinder block 3 is output to rotate a cab 103 and move a traveling body 102.

The casing 2 comprises a front housing 6 having an opening 6a, and a rear flange 7 that closes the opening 6a of the front housing 6. The cylinder block 3 is housed within the front housing 6. The rear flange 7 is formed with an inlet/outlet port 8 through which hydraulic oil is supplied and discharged. Hydraulic oil is supplied to the cylinder block 3 and discharged from the cylinder block 3 via this inlet/outlet port 8.

The cylinder block 3 is fitted and fixed to a shaft (not shown) that is rotatably supported within the front housing 6. The axis of the shaft coincides with a rotation axis C, so that the cylinder block 3 rotates about the rotation axis C.
The cylinder block 3 is formed in a cylindrical shape. A plurality of cylinder chambers 9 are formed in the cylinder block 3 so as to surround a shaft (not shown).

The multiple cylinder chambers 9 are arranged at equal intervals along a pitch circle concentric with the rotation axis C. The cylinder chambers 9 are recesses that are open on the bottom 6b side of the front housing 6 and closed on the rear flange 7 side. At the end 3a of the cylinder block 3 on the rear flange 7 side, cylinder ports 10 are formed at positions corresponding to each cylinder chamber 9, connecting each cylinder chamber 9 to the outside of the cylinder block 3. The cylinder ports 10 communicate with the supply and exhaust ports 8 of the rear flange 7 via the valve plate 4.

A piston 11 is housed in each cylinder chamber 9 so that it can freely reciprocate along the direction of the rotation axis C. This causes the piston 11 to rotate around the rotation axis C as the cylinder block 3 rotates. A cavity is formed inside the piston 11 to store the hydraulic oil in the cylinder chamber 9. The reciprocating motion of the piston 11 is linked to the intake of hydraulic oil into the cylinder chamber 9 and the exhaust of hydraulic oil from the cylinder chamber 9. Details will be described later.

The end of the piston 11 on the bottom 6b side of the front housing 6 is in sliding contact with the sliding surface of a swash plate (not shown) provided on the inner surface of the bottom 6b. The sliding surface of the swash plate is a flat surface inclined with respect to the rotation axis C. When hydraulic oil is supplied into the cylinder chamber 9, the swash plate has the role of converting the force pushing the piston 11 due to the pressure of the hydraulic oil into a force in the direction around the rotation axis C. Details will be described later.

<Valve plate>
The valve plate 4 is a disk-shaped member disposed between the rear flange 7 and the end 3a of the cylinder block 3. The valve plate 4 is fixed to the rear flange 7. The valve plate 4 remains stationary with respect to the rear flange 7 even when the cylinder block 3 rotates about the rotation axis C. The cylinder block 3 is supported by the static pressure of an oil film of hydraulic oil formed between the valve plate 4 and the end 3a of the cylinder block 3.

FIG. 3 is a plan view of the valve plate 4. As shown in FIG.
2 and 3, a through hole 12 for inserting a shaft (not shown) is formed in the radial center of the valve plate 4 so as to penetrate in the thickness direction of the valve plate 4. An inner diameter side recess 13 having an annular shape when viewed from the direction of the rotation axis C is formed in a first surface 4a of the valve plate 4 facing the cylinder block 3 so as to surround the periphery of the through hole 12 and to communicate with the through hole 12. In addition, an outer diameter side recess 14 having an annular shape is formed in the first surface 4a of the valve plate 4 so as to follow the outer periphery.

The valve plate 4 has two supply and discharge ports 15 formed therein, which are connected to the cylinder ports 10 of the cylinder block 3. The two supply and discharge ports 15 are arranged symmetrically around the rotation axis C. Each supply and discharge port 15 is formed penetrating the valve plate 4 in the thickness direction. Each supply and discharge port 15 consists of a long recess 16 formed between the first surface 4a of the valve plate 4 on the cylinder block 3 side and the center of the valve plate 4 in the thickness direction, and three supply and discharge holes 17 formed between the center of the valve plate 4 in the thickness direction and the second surface 4b of the valve plate 4 on the rear flange 7 side. The long recess 16 and each supply and discharge hole 17 are connected to each other.

The long recess 16 is formed, for example, in an arc shape within a predetermined angle range around the rotation axis C, and in an elliptical shape. The pitch circle S of the long recess 16 is located on the rotation trajectory of the cylinder port 10 of the cylinder block 3. The three supply and discharge holes 17 are arranged at equal intervals in the circumferential direction of the long recess 16. Through such supply and discharge ports 15, the supply and discharge opening 8 of the rear flange 7 and the cylinder port 10 of the cylinder block 3 are connected and communicated.

As shown in Figures 2 and 3, when hydraulic oil is supplied to the cylinder chamber 9 through the supply and discharge port 8 and the cylinder port 10 of the rear flange 7, the piston 11 is pushed out of the cylinder chamber 9 by the pressure of the hydraulic oil. At this time, the reaction force of the piston 11 pushing against the sliding surface of the swash plate (not shown) is converted into a circumferential force around the rotation axis C, and the cylinder block 3 rotates together with the piston 11.

At the top dead center, when the piston 11 is pushed farthest out of the cylinder chamber 9, the piston 11 begins to move into the cylinder chamber 9 by a swash plate (not shown). When the piston 11 enters the cylinder chamber 9, the spatial volume within the cylinder chamber 9 is reduced, and hydraulic oil is discharged from the supply/discharge port 8 of the rear flange 7 via the cylinder port 10. At the bottom dead center, when the piston 11 is pushed farthest out of the cylinder chamber 9, the piston 11 is pushed out of the cylinder chamber 9 again. This process is repeated as the cylinder block 3 and the piston 11 rotate around the rotation axis C.

It should be noted that the number of cylinder chambers 9 (pistons 11) in the hydraulic motor 1 of the first embodiment is an odd number.
Generally, the number of cylinder chambers (pistons) in a hydraulic motor is an odd number. This is to minimize the flow fluctuation of the hydraulic oil. In other words, when the number of pistons is three or more and the number of pistons is an odd number, there is a flow rate fluctuation of twice the order. In contrast, when the number of pistons is an even number, if the hydraulic motor 1 is driven with the same phase difference, the flow rate fluctuation will be of the same order as the number of pistons, and the rate of fluctuation will be large.

Returning to FIG. 3, a pair of switching lands 18a, 18b (bottom dead center switching land 18a, top dead center switching land 18b) is formed on the first surface 4a of the valve plate 4 between both longitudinal ends of each long recess 16. In other words, the two supply and exhaust ports 15 are formed on both sides of the pair of switching lands 18a, 18b. The pair of switching lands 18a, 18b are flush with the first surface 4a. When the cylinder block 3 is rotated, the cylinder port 10 of the cylinder block 3 is switched between one of the two supply and exhaust ports 15 via the pair of switching lands 18a, 18b and the other.

In the following description, of the pair of switching lands 18a, 18b, the switching land 18a that corresponds to the point where the motion of the piston 11 transitions from bottom dead center to top dead center is referred to as the bottom dead center switching land 18a. Also, of the pair of switching lands 18a, 18b, the switching land 18b that corresponds to the point where the motion of the piston 11 transitions from top dead center to bottom dead center is referred to as the top dead center switching land 18b.

Notches 19 are formed on the first surface 4a of the valve plate 4, extending from both longitudinal ends of the long recess 45 toward each switching land 18a, 18b. The notches 19 are formed so as to taper from the longitudinal end of one long recess 45 toward the longitudinal end of the other long recess 45 when viewed from the direction of the rotation axis C. The notches 19 are also formed so that the notch depth gradually becomes shallower from the longitudinal end of one long recess 45 toward the longitudinal end of the other long recess 45. The tip position of the notch 19 is located on the pitch circle S of the long recess 16 of each supply/discharge port 15.

Furthermore, two detection holes 20a, 20b (bottom dead center detection hole 20a, top dead center detection hole 20b) are formed in the circumferential center of the pair of switching lands 18a, 18b, i.e., at the top dead center position and bottom dead center position of the piston 11 and on the pitch circle S. Of the two detection holes 20a, 20b, the bottom dead center detection hole (a detection hole in the claims, an example of a first detection hole) 20a is formed in the bottom dead center switching land 18a. Of the two detection holes 20a, 20b, the top dead center detection hole (a detection hole in the claims, an example of a second detection hole) 20b is formed in the top dead center switching land 18b.
Each of the detection holes 20a, 20b is formed to penetrate in the thickness direction of the valve plate 4. When the cylinder port 10 of the cylinder block 3 passes over each of the detection holes 20a, 20b, the hydraulic oil in the cylinder chamber 9 flows into each of the detection holes 20a, 20b via the cylinder port 10.

On the other hand, as shown in Fig. 2, the rear flange 7 is formed with a bottom dead center extension hole (an example of an extension hole in the claims, a first extension hole) 21a that is connected to the bottom dead center detection hole 20a. The rear flange 7 is also formed with a top dead center extension hole (an example of an extension hole in the claims, a second extension hole) 21b that is connected to the top dead center detection hole 20b. The extension holes 21a, 21b are formed in a straight line along the direction of the rotation axis C so as to penetrate the rear flange 7 in the thickness direction. The hydraulic oil that has flowed into the bottom dead center detection hole 20a flows into the bottom dead center extension hole 21a. The hydraulic oil that has flowed into the top dead center detection hole 20b flows into the top dead center extension hole 21b.
Here, the openings on the second surface 4b side of the two detection holes 20a, 20b formed in the valve plate 4 function as pressure extraction portions 25a, 25b that extract the pressure of the hydraulic oil flowing into these detection holes 20a, 20b to the respective extension holes 21a, 21b sides of the rear flange 7.

A bottom dead center pressure sensor (an example of the first pressure detection section, the first pressure detection section in the claims) 5a is provided on the outer surface 7a of the rear flange 7 (outer surface 2a of the casing 2) so as to communicate with the bottom dead center extension hole 21a. Also, a top dead center pressure sensor (an example of the first pressure detection section, the second pressure detection section in the claims) 5b is provided on the outer surface 7a of the rear flange 7 (outer surface 2a of the casing 2) so as to communicate with the top dead center extension hole 21b. In other words, the pressure sensors 5a and 5b are provided on the side of the casing 2 opposite the detection holes 20a and 20b of the extension holes 21a and 21b.

The pressure sensors 5a and 5b detect the pressure of the hydraulic oil that flows into the corresponding extension holes 21a and 21b. In other words, the pressure sensors 5a and 5b are attached to the pressure extraction parts 25a and 25b via the extension holes 21a and 21b. The pressure sensors 5a and 5b detect the pressure of the hydraulic oil that flows into the detection holes 20a and 20b via the extension holes 21a and 21b and the pressure extraction parts 25a and 25b. The pressure sensors 5a and 5b are connected to a control unit 22. The pressure detected by the pressure sensors 5a and 5b is output as a signal to this control unit 22.

The control unit 22 is connected to each of the pressure sensors 5a, 5b and is also connected to the hydraulic pump 110. Based on the signals output from the pressure sensors 5a, 5b, the control unit 22 obtains rotation information of the cylinder block 3. Since the cylinder block 3 and a shaft (not shown) rotate together, the rotation information of the cylinder block 3 is also the rotation information of the shaft (not shown).
The control unit 22 controls the drive of the hydraulic pump 110 based on the acquired rotation information of the cylinder block 3. The method of acquiring the rotation information of the cylinder block 3 by the control unit 22 will be described in detail later.

The hydraulic pump 110 is a so-called swash plate type variable displacement hydraulic pump, and discharges hydraulic oil. The flow rate of hydraulic oil discharged from the hydraulic pump 110 is controlled by the control unit 22 controlling the tilt angle of the swash plate 111 provided on the hydraulic pump 110. The discharge port 112 of such a hydraulic pump 110 is connected to the supply and discharge port 8 of the rear flange 7 of the hydraulic motor 1. As a result, the hydraulic oil discharged from the hydraulic pump 110 is supplied to the supply and discharge port 8 of the hydraulic motor 1.

<Method of acquiring rotation information of cylinder block by control unit>
Next, a method for obtaining rotation information of the cylinder block 3 by the control unit 22 will be described.
Here, the two extension holes 21a, 21b formed in the rear flange 7 are connected to the detection holes 20a, 20b of the valve plate 4. In other words, the pressure of the hydraulic oil in the bottom dead center extension hole 21a connected to the bottom dead center detection hole 20a is equal to the pressure of the hydraulic oil in the bottom dead center detection hole 20a. Also, the pressure of the hydraulic oil in the top dead center extension hole 21b connected to the top dead center detection hole 20b is equal to the pressure of the hydraulic oil in the top dead center detection hole 20b. In the following description, the pressure waveform of the hydraulic oil detected by the bottom dead center pressure sensor 5a is referred to as the A-phase pressure waveform. Also, the pressure waveform of the hydraulic oil detected by the top dead center pressure sensor 5b is referred to as the B-phase pressure waveform.

FIG. 4 is a graph showing a simplified A-phase pressure waveform and a B-phase pressure waveform.
As the cylinder block 3 rotates, the cylinder ports 10 of the cylinder block 3 are alternately positioned and not positioned above the detection holes 20a, 20b of the valve plate 4. Therefore, as shown in FIG. 4, the pressure waveforms of the A phase and the B phase are roughly rectangular waves (pulse waveforms). That is, when the corresponding detection holes 20a, 20b and the cylinder ports 10 are connected and communicate with each other, the pressure waveforms of each phase become higher (rise) as the hydraulic oil in the cylinder chamber 9 flows in. Note that, even when the piston 11 is at the bottom dead center position, the hydraulic oil in the cylinder ports 10 is not completely drained, so when the bottom dead center detection hole 20a and the cylinder ports 10 are connected and communicate with each other, the pressure in the bottom dead center detection hole 20a becomes higher.

On the other hand, the pressure waveform of each phase drops (falls) when the corresponding detection hole 20a, 20b is disconnected from the cylinder port 10. Note that in FIG. 4, the pressure waveform of each phase is shown as a perfect square wave, but in reality, each detection hole 20a, 20b and the cylinder port 10 gradually connect and communicate with each other as the cylinder block 3 rotates, so the rise and fall of the pressure waveform of each phase is actually somewhat smooth (slightly unstable rise and fall).

Here, the bottom dead center detection hole 20a and the top dead center detection hole 20b are arranged opposite to each other across the rotation axis C. In other words, the bottom dead center detection hole 20a and the top dead center detection hole 20b are arranged at an interval of 180° mechanical angle. In addition, the number of cylinder chambers 9 (pistons 11) is odd. Therefore, the pressure waveform of the A phase and the pressure waveform of the B phase are out of phase by 90°. Therefore, the control unit 22 obtains the rotation direction of the cylinder block 3 as rotation information of the cylinder block 3 based on the phase difference between the pressure waveform of the A phase and the pressure waveform of the B phase. In other words, the control unit 22 detects the rising order of the pulses in the pressure waveform of the A phase and the rising order of the pulses in the pressure waveform of the B phase (sequence detection process). Based on the rising order of the pulses, the rotation direction of the cylinder block 3 is determined (rotation direction determination process). Alternatively, the control unit 22 detects the falling order of the pulses in the pressure waveform of the A phase and the falling order of the pulses in the pressure waveform of the B phase (sequence detection process). The rotation direction of the cylinder block 3 is determined based on the falling order of these pulses (rotation direction determination process).

The control unit 22 also has a calculation unit 23 that calculates the rotation speed of the cylinder block 3, and a memory unit 24. The calculation unit 23 has a count calculation unit 23a that counts the pulses of the pressure waveform of each phase and outputs a count value, a timer 23b that measures the time for which the pulses are counted, and a reset unit 23c that resets the count value calculated by the count calculation unit 23a (see FIG. 2 for all of these).

The calculation unit 23 uses the count calculation unit 23a and the timer 23b to determine the frequency of the A-phase pressure waveform or the B-phase pressure waveform (frequency calculation process). The calculation unit 23 performs FV conversion on the determined frequency to generate a voltage value. The storage unit 24 stores a calibration coefficient in advance. The calculation unit 23 multiplies the voltage value generated by the FV conversion by the calibration coefficient to calculate the rotation speed (rotational speed) of the cylinder block 3 (rotation speed calculation process).

The calculation unit 23 also calculates the count value by the count calculation unit 23a for each rotation direction of the cylinder block 3 (counting process). Furthermore, the calculation unit 23 calculates the rotation angle of the cylinder block 3 based on the count value for each rotation direction of the cylinder block 3 (rotation angle calculation process). By accumulating the rotation angles, it is possible to calculate the rotation angle formed in a certain time period and the accumulated rotation angle when the rotation angle is calculated multiple times. In this case, in order to suppress the accumulated error, the count value of the count calculation unit 23a is reset by the reset unit 23c when a certain rotation angle is reached, thereby resetting the accumulated rotation angle.

The timer 23b measures, for example, only a preset time. In this case, the rotation angle is calculated in multiple steps, which may result in a discrepancy with the actual change in rotation speed. For this reason, when a certain rotation angle is reached, the count value of the count calculation unit 23a is reset by the reset unit 23c, thereby resetting the cumulative rotation angle. Specific reset timings are, for example, as follows:

FIG. 5 is a schematic configuration diagram of the construction machine 100 as viewed from above.
5, the construction machine 100 is provided with a rotating body side reset position 101a provided on the rotating body 101 side and a running body side reset position 102a provided on the running body side 102 side. Since the rotating body 101 rotates with respect to the running body 102, the running body side reset position 102a is fixed, and the rotating body side reset position 101a rotates as the rotating body 101 rotates.
With this configuration, when the rotating body side reset position 101a is positioned at the running body side reset position 102a, the count value is reset by the reset unit 23c.

In this manner, in the first embodiment described above, two detection holes 20a, 20b are formed in the pair of switching lands 18a, 18b of the valve plate 4, penetrating in the thickness direction of the valve plate 4. In addition, two extension holes 21a, 21b are formed in the rear flange 7, which are connected to the detection holes 20a, 20b via the pressure extraction parts 25a, 25b. Pressure sensors 5a, 5b that detect the pressure of the hydraulic oil flowing into each extension hole 21a, 21b are provided on the outer surface 7a of the rear flange 7. In other words, the pressure sensors 5a, 5b are provided on the opposite side of the detection holes 20a, 20b of each extension hole 21a, 21b in the casing 2. The detection holes 20a, 20b and the extension holes 21a, 21b are connected to the cylinder port 10 of the cylinder block 3, and are repeatedly connected and blocked, so that the pressure of the hydraulic oil becomes a square wave (pulse waveform) and is detected by each pressure sensor 5a, 5b. Therefore, the control unit 22 can easily obtain rotation information such as the rotation direction, rotation speed, and rotation angle of the cylinder block 3 (shaft not shown). In addition, since no external rotation detection equipment is required, the structure of the hydraulic motor 1 can be simplified. In addition, the hydraulic motor 1 as a whole can be made inexpensively.

Furthermore, by forming an extension hole 21 in the rear flange 7, the pressure sensors 5a and 5b can be provided on the rear flange 7. In other words, the layout freedom of the pressure sensors 5a and 5b for detecting the pressure of the hydraulic oil in the detection holes 20a and 20b can be increased. In addition, the pressure sensors 5a and 5b can be easily fixed to the casing 2.

In addition, each extension hole 21a, 21b is formed in a straight line along the direction of the rotation axis C so as to penetrate the rear flange 7 in the thickness direction. This makes it possible to reduce pressure loss of the hydraulic oil flowing into each extension hole 21a, 21b. Therefore, even when the extension hole 21 is formed, it is possible to obtain highly accurate rotation information of the cylinder block 3.

Furthermore, by forming the extension holes 21a, 21b in the rear flange 7, the rear flange 7 in which the supply and discharge ports 8 are formed can be used as the location for arranging the pressure sensors 5a, 5b. For the entire casing 2, it is easy to ensure space above the rear flange 7 for arranging the pressure sensors 5a, 5b. Therefore, the pressure sensors 5a, 5b can be easily fixed onto the casing 2.

The two detection holes 20a, 20b are formed at the top dead center position and bottom dead center position of the piston 11 in the valve plate 4. Therefore, the pressure sensors 5a, 5b can detect a pressure waveform of the hydraulic oil that is well balanced between a high pressure waveform (pressure waveform of the hydraulic oil at the bottom dead center position) and a low pressure waveform (pressure waveform of the hydraulic oil at the top dead center position). This makes it possible to obtain highly accurate rotation information of the hydraulic motor 1.
In addition, two pressure waveforms with different phases (pressure waveform of phase A and pressure waveform of phase B) can be obtained by the two detection holes 20a and 20b. By using these two pressure waveforms with a phase difference, rotation information such as the rotation direction of the cylinder block 3 can be easily obtained.

In particular, since the number of cylinder chambers 9 (pistons 11) is generally odd, including in the above-mentioned embodiment, the phases of the A-phase pressure waveform and the B-phase pressure waveform are shifted by exactly 90°. Therefore, regardless of the rotation direction of the cylinder block 3, the output signals of the pressure sensors 5a, 5b can be detected at the same timing, and rotation information of the cylinder block 3 can be obtained.

To obtain the rotation information, the control unit 22 has a calculation unit 23 that calculates the rotation speed of the cylinder block 3, and a storage unit 24. This makes it possible to easily obtain the rotation speed of the cylinder block 3. The calculation unit 23 can easily calculate the rotation direction of the cylinder block 3 based on the A-phase pressure waveform and the B-phase pressure waveform.
More specifically, the control unit 22 detects the rising edge of the pulses in the pressure waveform of the A phase and the rising order of the pulses in the pressure waveform of the B phase (sequence detection process). Based on this rising order of the pulses, the rotation direction of the cylinder block 3 is determined (rotation direction determination process). Alternatively, the control unit 22 detects the falling edge of the pulses in the pressure waveform of the A phase and the falling order of the pulses in the pressure waveform of the B phase (sequence detection process). Based on this falling order of the pulses, the rotation direction of the cylinder block 3 is determined (rotation direction determination process). Therefore, the rotation direction of the cylinder block 3 can be easily calculated using the pressure waveform of the A phase and the pressure waveform of the B phase.

The calculation unit 23 also has a count calculation unit 23a that counts the pulses of the pressure waveform for each phase and outputs the count value. Therefore, the rotation angle of the cylinder block 3 can be easily calculated based on the count value by the count calculation unit 23a.

Furthermore, the calculation unit 23 has a timer 23b that measures the time for which the pulses are counted, and a reset unit 23c that resets the count value by the count calculation unit 23a. The calculation unit 23 then uses the count calculation unit 23a and the timer 23b to determine the frequency of the A-phase pressure waveform or the B-phase pressure waveform (frequency calculation process). The calculation unit 23 performs FV conversion on the determined frequency to generate a voltage value. Based on this voltage value, the calculation unit 23 calculates the rotational speed (rotational speed) of the cylinder block 3 (rotational speed calculation process). This makes it easy to calculate the rotational speed of the cylinder block 3.
Furthermore, the reset unit 23c can reduce accumulated errors when calculating the rotation angle of the cylinder block 3.

[Second embodiment]
Next, a second embodiment of the present invention will be described with reference to Fig. 6. Note that the same features as those in the first embodiment are given the same reference numerals and the description thereof will be omitted.
FIG. 6 is an enlarged cross-sectional view of a portion of a hydraulic motor 201 according to the second embodiment, which corresponds to a bottom dead center detection hole 20a of a valve plate 204.
In the second embodiment, the configuration is the same as that of the first embodiment, such as the two detection holes 20a, 20b formed in the valve plate 204. The configurations of the locations of the valve plate 204 corresponding to the detection holes 20a, 20b are the same, so in Fig. 5, only the location of the valve plate 204 corresponding to the bottom dead center detection hole 20a is shown, and the top dead center detection hole 20b is not shown. In the following description, only the bottom dead center detection hole 20a will be described, but the top dead center detection hole 20b has the same configuration.

<Piston Storage Recess and Closed Piston>
6, a piston accommodating recess 31 is formed at a position corresponding to the bottom dead center detection hole 20a on the second surface (an example of a surface in the claims) 204b side of the valve plate 204. A blocking piston 32 is accommodated in this piston accommodating recess 31. These points are different from the first embodiment described above.
The piston accommodating recess 31 is formed in a circular shape when viewed from the direction of the rotation axis C. The piston accommodating recess 31 is connected to the bottom dead center detection hole 20a at the radial center thereof.

The blocking piston 32 is formed in a disk shape. The thickness of the blocking piston 32 is slightly thinner than the depth of the piston accommodating recess 31. The outer diameter of the blocking piston 32 is slightly smaller than the inner diameter of the piston accommodating recess 31.
A piston hole 33 is formed in the radial center of the blocking piston 32 so as to penetrate the blocking piston 32 in the thickness direction. The bottom dead center detection hole 20a of the valve plate 204 and the bottom dead center extension hole 21a of the rear flange 7 communicate with each other via the piston hole 33. The opening of the bottom dead center detection hole 20a formed in the valve plate 204 on the piston storage recess 31 side functions as a pressure extraction portion 25a that extracts the pressure of the hydraulic oil flowing into the bottom dead center detection hole 20a to the piston hole 33 side.

In addition, an O-ring (an example of a seal in the claims) 34 is provided on the outer peripheral surface of the blocking piston 32 near the bottom surface 31a of the piston storage recess 31. The O-ring 34 ensures sealing between the inner peripheral surface of the piston storage recess 31 and the outer peripheral surface of the blocking piston 32.

<Action of the obstruction piston>
Next, the operation of the blocking piston 32 will be described.
When hydraulic oil flows into the bottom dead center detection hole 20a of the valve plate 204, the hydraulic oil flows into the piston accommodating recess 31. Then, an oil film is formed between the bottom surface 31a of the piston accommodating recess 31 and the blocking piston 32, and the static pressure of this oil film pushes the blocking piston 32 toward the rear flange 7. This improves the sealing performance between the blocking piston 32 and the rear flange 7.

Hydraulic oil is also flowed into the piston hole 33 of the blocking piston 32, and further into the bottom dead center extension hole 21a of the rear flange 7. At this time, the sealing between the blocking piston 32 and the rear flange 7 is ensured, so that the hydraulic oil is prevented from leaking out from between the blocking piston 32 and the rear flange 7. In addition, an O-ring 34 is provided on the outer peripheral surface of the blocking piston 32, so that the hydraulic oil is prevented from leaking out from between the inner peripheral surface of the piston storage recess 31 and the outer peripheral surface of the blocking piston 32.

Therefore, according to the second embodiment described above, the same effect as the first embodiment described above is achieved. In addition, since the piston storage recess 31 is formed in the valve plate 204 and the blocking piston 32 is provided in this piston storage recess 31, it is possible to prevent the hydraulic oil from leaking out from between the rear flange 7 and the valve plate 204. Therefore, the bottom dead center pressure sensor 5a can detect the pressure of the hydraulic oil in the bottom dead center detection hole 20a with greater accuracy. By providing an O-ring 34 on the outer peripheral surface of the blocking piston 32, the bottom dead center pressure sensor 5a can detect the pressure of the hydraulic oil in the bottom dead center detection hole 20a with even greater accuracy.

The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention.
For example, in the above embodiment, the valve plate 4, 204 has the detection holes 20a, 20b at the bottom dead center position and the top dead center position of the piston 11. However, this is not limited to this, and the detection holes 20a, 20b may be formed between the supply and discharge ports 15 of the valve plate 4, 204, that is, at any location between the bottom dead center switching land 18a and the top dead center switching land 18b. In this case, the phase difference between the pressure waveform of the A phase and the pressure waveform of the B phase is not limited to 90°, but may be any value between 10° to 170° or between 190° to 350°. By configuring in this way, it is possible to prevent the pressure waveforms of each phase from being unstable at the time of rising or falling, which makes it difficult to obtain accurate rotation information of the cylinder block 3. Preferably, the phase difference between the pressure waveform of the A phase and the pressure waveform of the B phase is 90° or 270°. Even if it is 270°, the same effect as the first embodiment described above is obtained.

In the above embodiment, the case where two detection holes 20a, 20b are formed in the valve plate 4, 204 has been described. However, this is not limited to this, and it is sufficient that at least one detection hole is formed. If one detection hole is formed, the control unit 22 can obtain the rotation speed and rotation angle as rotation information of the cylinder block 3.

In the above embodiment, the extension holes 21a, 21b are formed in the rear flange 7, and the pressure of the hydraulic oil flowing into these extension holes 21a, 21b is detected by the respective pressure sensors 5a, 5b. However, this is not limited to the above, and the extension holes 21a, 21b do not have to be formed. The pressure of the hydraulic oil flowing into each detection hole 20a, 20b may be detected by the respective pressure sensors 5a, 5b.
Furthermore, the hydraulic motors 1, 201 may have pressure extraction units 25a, 25b that extract the pressure of the hydraulic oil flowing into the detection holes 20a, 20b. The pressure of the hydraulic oil extracted by the pressure extraction units 25a, 25b may be detected by the pressure sensors 5a, 5b, etc.

In the above embodiment, the extension holes 21a, 21b are formed in a straight line along the direction of the rotation axis C so as to penetrate the rear flange 7 in the thickness direction. However, this is not limited to this, and the shape of the extension holes 21a, 21b can be changed depending on the layout of the pressure sensors 5a, 5b.

In the above embodiment, the case where two supply/discharge ports 15 are formed in the valve plate 4, 204 has been described. However, this is not limited to this, and the number of supply/discharge ports 15 may be three or more. It is sufficient that the detection holes 20a, 20b are formed between the supply/discharge ports 15 adjacent to each other around the rotation axis C among the multiple supply/discharge ports 15.
In the above-described embodiment, the hydraulic motor 1, 201 driven by hydraulic oil has been described. However, the present invention is not limited to this, and the above-described configuration can be adopted in fluid machines driven by various fluids.

In the above embodiment, as a method of calculating the rotation speed of the cylinder block 3, the calculation unit 23 calculates the frequency of the pressure waveform of the A phase or the pressure waveform of the B phase using the count calculation unit 23a and the timer 23b, and performs FV conversion on this frequency to generate a voltage value. Also, a calibration coefficient is stored in advance in the memory unit 24, and the calculation unit 23 calculates the rotation speed of the cylinder block 3 by multiplying the voltage value generated by FV conversion by the calibration coefficient. However, this is not limited to this, and the rotation speed of the cylinder block 3 may be calculated based on these pulses and time by measuring the time for which the count calculation unit 23a counts pulses (counting process) using the timer 23b. Also, the rotation speed of the cylinder block 3 may be calculated based on the time until a certain count value is reached by the count calculation unit 23a (rotation speed calculation process).

In the above embodiment, a case has been described in which one running body side reset position 102a is set on the running body 102. However, this is not limited to this, and two or more running body side reset positions 102a may be set. For example, when multiple running body side reset positions 102a are set, the running body side reset positions 102a can be arranged at mechanical angle intervals of 90° to further reduce the accumulated error when the rotation angle of the cylinder block 3 is calculated by the reset unit 23c.

Among the embodiments disclosed in this specification, those that are composed of multiple objects may be integrated into one object, and conversely, those that are composed of one object may be separated into multiple objects. Regardless of whether they are integrated or not, it is sufficient that the object of the invention can be achieved.

1,201...hydraulic motor (fluid machinery), 2...casing (housing), 3...cylinder block, 4,204...valve plate, 5a...bottom dead center pressure sensor (pressure detection section, first pressure detection section), 5b...top dead center pressure sensor (pressure detection section, second pressure detection section), 7...rear flange (housing), 8...supply/discharge port, 9...cylinder chamber, 10...cylinder port, 11...piston, 15...supply/discharge port, 20a...bottom dead center detection hole (detection hole, first detection hole ), 20b...Top dead center detection hole (detection hole, second detection hole), 21a...Bottom dead center extension hole (extension hole, first extension hole), 21b...Top dead center extension hole (extension hole, second extension hole), 23...Calculation section, 23a...Count calculation section, 23b...Timer, 23c...Reset section, 25a, 25b...Pressure extraction section, 31...Piston storage recess, 32...Closed piston, 33...Piston hole, 34...O-ring (seal section), 204b...Second surface (one surface), C...Rotation axis

Claims (22)

Housing and
a cylinder block that is accommodated in the housing and is rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, the valve plate having detection holes formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a pressure output section that outputs the pressure of the fluid flowing into the detection hole;
a pressure detection unit attached to the pressure output unit and detecting a pressure of the fluid;
a calculation unit that calculates a rotation speed of the cylinder block based on a detection result of the pressure detection unit;
A fluid machine comprising: Housing and
a cylinder block that is accommodated in the housing and is rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, the valve plate having detection holes formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a pressure output unit that outputs the pressure of the fluid flowing into the detection hole,
The valve plate is
a piston receiving recess formed on one surface of the housing at a location where the detection hole is formed;
a blocking piston that is accommodated in the piston accommodating recess so as to block an opening of the piston accommodating recess and has a piston hole that communicates with the detection hole;
A fluid machine comprising: a piston provided in the cylinder chamber and capable of reciprocating along a rotation axis of the cylinder block ,
3. The fluid machine according to claim 1, wherein the detection hole is formed in the valve plate at least one of a top dead center position and a bottom dead center position of the piston. The housing has an extension hole communicating with the detection hole,
The fluid machine according to claim 1 , wherein the pressure output portion outputs the pressure of the detection hole through the extension hole. 5. The fluid machine according to claim 4, wherein the extension holes are formed in a straight line. The fluid machine according to claim 1 , wherein the housing is a rear flange having an intake and exhaust port through which the fluid is supplied and exhausted, the intake and exhaust port being connected to the supply and exhaust port. The valve plate is
a piston receiving recess formed on one surface of the housing at a location where the detection hole is formed;
a blocking piston that is accommodated in the piston accommodating recess so as to block an opening of the piston accommodating recess and has a piston hole that communicates with the detection hole;
The fluid machinery according to any one of claims 1 to 6, further comprising: 8. The fluid machine according to claim 2, further comprising a seal portion that prevents leakage of the fluid from between an inner surface of the piston accommodating recess and an outer surface of the blocking piston. The detection hole includes at least a first detection hole and a second detection hole,
the pressure detection unit includes a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal, and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal,
The fluid machine according to claim 1 , wherein the first detection hole and the second detection hole are formed so that an output signal of the first pressure detection portion and an output signal of the second pressure detection portion have a phase difference. the housing has a first extension hole communicating with the first detection hole and a second extension hole communicating with the second detection hole,
the first pressure detection portion is provided on a side of the first extension hole opposite to the first detection hole,
The fluid machine according to claim 9 , wherein the second pressure detection portion is provided on a side of the second extension hole opposite to the second detection hole. The fluid machine according to claim 9 or 10, wherein the phase difference is any value between 10° and 170°, or between 190° and 350°. The fluid machinery according to claim 11, wherein the phase difference is 90° or 270°. The fluid machine according to claim 9 , further comprising a calculation unit that calculates a rotation direction of the cylinder block based on an output signal of the first pressure detection unit and an output signal of the second pressure detection unit. The fluid machine according to claim 13, wherein the calculation unit has a count calculation unit that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit and calculates the rotation angle of the cylinder block based on the count value. The fluid machine according to claim 14, wherein the calculation unit has a reset unit that resets the count value of the count calculation unit when the rotation angle of the cylinder block reaches a certain angle. The fluid machinery according to claim 14 , wherein the calculation unit has a timer that measures a time for which the pulses are counted. Housing and
a cylinder block that is accommodated in the housing and is rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, and a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal; and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal;
a calculation unit that calculates a rotation direction of the cylinder block based on an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
A method for calculating rotation information of a fluid machine comprising:
the calculation unit detects a pulse rise order of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit;
a rotation direction determination step of determining a rotation direction of the cylinder block based on the order detected in the order detection step;
The rotation information calculation method includes the steps of: Housing and
a cylinder block that is accommodated in the housing and is rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, and a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal; and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal;
a calculation unit that calculates a rotation direction of the cylinder block based on an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
A method for calculating rotation information of a fluid machine comprising:
a counting step of the calculation unit counting pulses of at least one of an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
a rotation angle calculation step of calculating a rotation angle of the cylinder block based on the count value in the counting step;
The rotation information calculation method includes the steps of: Housing and
a cylinder block that is accommodated in the housing and is rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, and a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal; and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal;
a calculation unit that calculates a rotation direction of the cylinder block based on an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
Equipped with
The calculation unit is
a count calculation unit that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit and calculates a rotation angle of the cylinder block based on a count value;
A timer that measures the time for which the pulses are counted;
A method for calculating rotation information of a fluid machinery having
the calculation unit calculates a frequency of at least one of an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
a rotation speed calculating step of calculating a rotation speed of the cylinder block based on a voltage value generated by FV converting the frequency obtained in the frequency calculating step. Housing and
a cylinder block that is accommodated in the housing and is rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, and a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal; and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal;
a calculation unit that calculates a rotation direction of the cylinder block based on an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
Equipped with
The calculation unit is
a count calculation unit that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit and calculates a rotation angle of the cylinder block based on a count value;
A timer that measures the time for which the pulses are counted;
A method for calculating rotation information of a fluid machinery having
a counting step of the calculation unit counting pulses of at least one of an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
a rotation speed calculation step of calculating a rotation speed of the cylinder block based on a count value in the counting step within a certain period of time;
The rotation information calculation method includes the steps of: Housing and
a cylinder block that is accommodated within the housing so as to be rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged, and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, and a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a first pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the first detection hole as a signal; and a second pressure detection unit that outputs a detection result of the pressure of the fluid flowing into the second detection hole as a signal;
a calculation unit that calculates a rotation direction of the cylinder block based on an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
Equipped with
The calculation unit is
a count calculation unit that counts pulses of at least one of the output signals of the first pressure detection unit and the output signal of the second pressure detection unit and calculates a rotation angle of the cylinder block based on a count value;
A timer that measures the time for which the pulses are counted;
A method for calculating rotation information of a fluid machinery having
a counting step of the calculation unit counting pulses of at least one of an output signal of the first pressure detection unit and an output signal of the second pressure detection unit;
a rotation speed calculation step of calculating a rotation speed of the cylinder block based on a time required for the count value to reach a certain count value in the counting step;
The rotation information calculation method includes the steps of: A fluid machine,
a vehicle body on which the fluid machine is mounted and which is driven by the fluid machine,
The fluid machine includes:
Housing and
a cylinder block that is accommodated within the housing and is rotatable about a rotation axis, the cylinder block having a cylinder chamber through which a fluid is supplied and discharged and a cylinder port that communicates with the cylinder chamber;
a valve plate disposed between the housing and the cylinder block in the direction of the rotation axis of the cylinder block , the valve plate having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder ports, and a detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder ports;
a pressure output section that outputs the pressure of the fluid flowing into the detection hole;
Construction machinery equipped with

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