Internal gear pump and shock absorber with ride height adjustment function

Abstract

To provide an internal gear pump capable of improving pump efficiency, and a buffer with a vehicle height adjustment function that comprises the internal gear pump.SOLUTION: An internal gear pump 1 in the present invention comprises: a case 2 having a pump chamber 7a1; an outer rotor 3 that is annular, has internal teeth 3a on an inner periphery, and is housed in the pump chamber 7a1; an inner rotor 4 that is housed in the pump chamber 7a1, and has external teeth 4a that are inserted into the inner peripheral side of the outer rotor 3 and mesh with the outer rotor 3; and a motor 5 that revolves and autorotates the inner rotor 4 within the outer rotor 3.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an internal gear pump Pu and a shock absorber with a vehicle height adjustment function.

Background Art

[0002] An internal gear pump includes a case, an outer rotor which is annular and rotatable circumferentially within the case and is an internal gear, an inner rotor which is accommodated within the case and is inserted on the inner circumferential side of the outer rotor and meshes with the outer rotor, and a motor for driving the inner rotor.

[0003] More specifically, the rotation axis of the inner rotor is disposed at a position eccentric from the rotation center of the outer rotor. When the inner rotor is rotationally driven by the motor, the outer rotor meshed with the inner rotor is also driven together with the inner rotor (see, for example, Patent Document 1).

[0004] [[ID=CO22]]In the internal gear pump configured as described above, suction and discharge of a liquid can be continuously performed by utilizing the change in the volume of the cavity between the inner rotor and the outer rotor as the inner rotor and the outer rotor rotate. The contents 积が変化することを利用して液体の吸込と吐出とを連続して行うことができる。

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the internal gear pump configured as described above, both the inner rotor and the outer rotor need to be driven, so during operation, resistance is encountered due to the frictional force between the inner rotor and the outer rotor, the frictional force between the case and the inner rotor, and the frictional force between the case and the outer rotor.

[0007] Therefore, internal gear pumps are required to improve pump efficiency by reducing losses caused by frictional forces at three points.

[0008] Therefore, the present invention aims to provide an internal gear pump and a shock absorber with a ride height adjustment function that can improve pump efficiency. [Means for solving the problem]

[0009] To solve the aforementioned problems, the internal gear pump in the problem-solving means of the present invention is characterized by comprising a case having a pump chamber, an annular outer rotor having internal teeth on its inner circumference and housed in the pump chamber, an inner rotor housed in the pump chamber and inserted into the inner circumference side of the outer rotor and having external teeth that mesh with the outer rotor, and a motor that drives the inner rotor to revolve and rotate within the outer rotor.

[0010] In the internal gear pump configured as described above, the outer rotor does not rotate when the inner rotor rotates to discharge the liquid. Therefore, frictional force is generated at only two points during liquid discharge: between the outer rotor and the inner rotor, and between the inner rotor and the case. This reduces the number of friction points compared to conventional internal gear pumps. Thus, according to the internal gear pump of this embodiment, liquid of Because the frictional resistance during discharge can be reduced, losses can be reduced and pump efficiency can be improved compared to conventional internal gear pumps.

[0011] Furthermore, the internal gear pump is installed in a case and connects the high-pressure side and the low-pressure side, which are separated by the case. ruThe pump is equipped with an operateable check valve that opens and closes the circuit, and the open / closed state of the operateable check valve can be switched depending on the direction of torque applied to the outer rotor. The valve may close when the inner rotor revolves in one direction and open when the inner rotor revolves in the other direction. In an internal gear pump configured in this way, the operateable check valve is opened and closed using the torque transmitted from the motor to the outer rotor via the inner rotor to drive the operateable check valve, so no drive source other than the motor is required, and thus manufacturing costs can be reduced.

[0012] Furthermore, the internal gear pump may draw liquid into a cavity between the outer rotor and the inner rotor from the vertical direction, which is the axial direction of the outer rotor, and discharge the liquid through multiple ports that connect the inner and outer circumferences of the outer rotor and lead to each cavity. With an internal gear pump configured in this way, the vertical height of the case can be shortened, so the overall height of the internal gear pump can be made compact, and even when the internal gear pump is integrated with equipment that receives liquid from the equipment to form a hydraulic device, the mountability of the equipment is improved and the hydraulic device can be made smaller.

[0013] Furthermore, the shock absorber with ride height adjustment function comprises a shock absorber body having a cylinder, a piston inserted axially movably into the cylinder and dividing the inside of the cylinder into an extension chamber and a compression chamber, a piston rod inserted into the extension chamber and axially movable relative to the cylinder and connected to the piston, and an outer cylinder covering the cylinder, and an internal gear pump, and the case stores liquid in the annular gap between the cylinder and the outer cylinder. Ru Ta The cylinder is connected to the compression chamber and compensates for the volume through which the piston rod moves in and out of the cylinder. Ruri It is separated into a reservoir room.

[0014] In a shock absorber with ride height adjustment function configured in this way, damping force is exerted during expansion and contraction to suppress vibrations of the vehicle body. Furthermore, by driving an internal gear pump to discharge liquid from the tank into the reservoir chamber, the shock absorber body can be extended to raise the ride height, and by using the internal gear pump to discharge liquid from the reservoir chamber to the tank, the shock absorber body can be contracted to lower the ride height. In addition, since the internal gear pump separates the tank and the reservoir chamber with a case, the pump part can be placed close to the shock absorber body, and the suction passage and discharge passage for supplying liquid from the tank to the reservoir chamber, and the discharge passage for discharging liquid from the reservoir chamber to the tank can be consolidated into the case and simplified. Therefore, with a shock absorber with ride height adjustment function, even with an internal gear pump, the size can be reduced and manufacturing costs can be lowered. Furthermore, in a shock absorber with ride height adjustment function configured in this way, the internal gear pump is mounted in the middle section of the cylinder above the lower end of the cylinder, thus protecting the motor from flying stones while the vehicle is in motion and from water splashes when driving on flooded roads. [Effects of the Invention]

[0015] The internal gear pump and shock absorber with ride height adjustment function of the present invention can improve pump efficiency. [Brief explanation of the drawing]

[0016] [Figure 1] This is a longitudinal cross-sectional view of a shock absorber with a ride height adjustment function to which an internal gear pump according to one embodiment is applied. [Figure 2] This is a cross-sectional view of an internal gear pump according to one embodiment. [Figure 3] This is a longitudinal cross-sectional view of an internal gear pump according to one embodiment. [Figure 4] This diagram illustrates the operation of an internal gear pump in one embodiment. [Figure 5] This figure shows a first modified example of an operated check valve in an internal gear pump according to one embodiment. [Figure 6] This figure shows a second modified example of the operated check valve in an internal gear pump according to one embodiment. [Figure 7] It is a figure showing a first modification example of a check valve in an internal gear pump according to an embodiment.

Embodiments for Carrying out the Invention

[0017] Hereinafter, the present invention will be described based on each embodiment shown in the drawings. The internal gear pump 1 in one embodiment, as shown in FIGS. 1 to 4, includes a case 2 having a pump chamber 7a1, an outer rotor 3 that is annular and has internal teeth 3a on its inner circumference and is housed in the pump chamber 7a1, an inner rotor 4 that is housed in the pump chamber 7a1 and has external teeth 4a that are inserted on the inner circumferential side of the outer rotor 3 and mesh with the outer rotor 3, and a motor that drives the inner rotor 4 to revolve and rotate within the outer rotor 3. 6 The internal gear pump 1 of the present embodiment is integrally attached to the shock absorber body D as shown in FIG. 1 and can supply and discharge liquid to and from the shock absorber body D. The internal gear pump 1 and the shock absorber body D constitute a shock absorber SA with a vehicle height adjustment function, and the shock absorber body D is used by being interposed between the vehicle body and the wheels (not shown) together with the suspension spring S.

[0018] First, the internal gear pump 1 will be described. As shown in FIGS. 1 to 4, the case 2 includes a case body 7 having a pump chamber 7a1 that houses the outer rotor 3 and the inner rotor 4, and a lid 8 that is overlapped with the case body 7.

[0019] In the present embodiment, as shown in FIG. 2, in a plan view, both the pump portion 7a and the mounting portion 7b have a substantially circular outer peripheral shape, but the outer peripheral shape can be arbitrarily designed and changed.

[0020]

[0021] ​As mentioned above, the shape of the pump chamber 7a1 in plan view is approximately circular, and the diameter of the pump chamber 7a1 is set to a diameter that allows it to slide against the outer rotor 3 but does not hinder the circumferential rotation of the outer rotor 3 within the pump chamber 7a1. The pump section 7a is also provided with a fan-shaped recess 7a2 facing the mounting section 7b side of the pump chamber 7a1. The mounting section 7b is annular and extends to the side of the pump section 7a.

[0022] The lid 8 has an outer shape that matches that of the case body 7, and when placed on top of the case body 7, it includes a motor holding portion 8a that closes the pump chamber 7a1 of the case body 7, and an annular mounting portion 8b that is placed on top of the mounting portion 7b. The motor holding portion 8a has a hole 8a1 that leads to the pump chamber 7a1.

[0023] As shown in Figure 1, the case 2, which consists of a case body 7 and a lid 8, is fitted to the outer circumference of the middle portion of the cylinder 30 of the buffer body D, and is interposed between the upper cylinder 33a and the lower cylinder 33b that form the outer cylinder 33 that covers the cylinder 30, and is mounted on the buffer body D. Furthermore, the case 2 divides the annular gap formed between the cylinder 30 and the outer cylinder 33 into the tank T, which is the upper low-pressure side in Figure 1, and the reservoir chamber R, which is the high-pressure side.

[0024] Case 2 is provided with a suction passage P1 that opens above the pump chamber 7a1. Furthermore, Case 2 is provided with a discharge passage P2 consisting of six passages 2a that open from the side wall surrounding the outer periphery of the pump chamber 7a1 and lead to the reservoir chamber R, and each of the six passages 2a is provided with a check valve 2b that allows only the flow of liquid from the pump chamber 7a1 to the reservoir chamber R. In addition, the recess 7a2 is provided in Case 2 and the circumferential direction of the recess 7a2 one endA passage P3a opens to the case 2 and communicates with the reservoir chamber R, which is on the high-pressure side. Similarly, a passage P3b, also provided in the case 2 and opening upward or radially to the side of the recess 7a2, communicates with the tank T. Passages P3a and P3b constitute a discharge passage P3 that connects the reservoir chamber R to the tank T. Furthermore, the case 2 is provided with a relief passage P4 that connects the tank T and the reservoir chamber R. The relief passage P4 is equipped with a relief valve that, when the pressure in the reservoir chamber R reaches the valve opening pressure, opens the relief passage P4, allowing only the flow of liquid from the reservoir chamber R to the tank T. 24 A system is in place.

[0025] Next, the outer rotor 3 is annular in shape and includes internal teeth 3a provided on its inner circumference, a convex portion 3b projecting radially from the outer circumference, and six ports 3c that penetrate radially through the wall thickness at six locations between the internal teeth 3a, 3a. The shape of the internal teeth 3a is a trochoidal curve tooth profile, but is not limited to the above.

[0026] Then, when the outer rotor 3 is housed in the pump chamber 7a1 of the case body 7, the protrusion 3b is inserted into the recess 7a2 as shown in Figure 2, and the outer circumference excluding the protrusion 3b slides against the side wall forming the pump chamber 7a1 of the case body 7. Convex portion 3b The circumferential width is, Recess 7a2 The recess 7a2 is shorter than the circumferential width, and houses the convex portion 3b, as well as a spherical valve body 23a positioned within the recess 7a2 on one side in the circumferential direction relative to the convex portion 3b, and a spring 23b positioned within the recess 7a2 on the other side in the circumferential direction relative to the convex portion 3b. The spring 23b is interposed in a compressed state between the other circumferential end of the recess 7a2 and the convex portion 3b of the outer rotor 3, biasing the valve body 23a toward the right in Figure 2 within the recess 7a2 via the convex portion 3b. The valve body 23a, spring 23b, and the convex portion 3b of the outer rotor 3 constitute the operate check valve 23. The convex portion 3b is located within the recess 7a2 Deba ne23b to the most contraction From the position where it is made to move, the valve body 23a in the circumferential direction of the recess 7a2 one endIt can move within a range up to a position where it contacts the periphery of the opening of the passage P3a that opens to the outer rotor. Therefore, the outer rotor 3 is allowed to rotate in the circumferential direction only within the range in which movement within the recess 7a2 of the convex portion 3b is permitted.

[0027] Furthermore, unless a force is applied from the outer rotor 3 in a direction that compresses the spring 23b, the valve body 23a, which is biased by the spring 23b, will not have the circumferential direction of the recess 7a2. one end The valve body 23a abuts against the periphery of the opening of passage P3a, which opens into the outlet, thereby cutting off communication between passage P3a and passage P3b and blocking the discharge passage P3. The valve body 23a is subjected to a force in the recess 7a2 that causes it to retract toward the other end due to the pressure in the reservoir chamber R. However, in the normal operating state of the shock absorber SA with ride height adjustment function, the biasing force of the spring 23b is greater than this force. Therefore, unless a force acts from the outer rotor 3 in the direction that compresses the spring 23b, the operate check valve 23 remains closed. On the other hand, when the outer rotor 3 receives a force in the counterclockwise direction in Figure 2, the convex portion 3b compresses the spring 23b, causing the valve body 23a to move away from the opening of passage P3a, and the operate check valve 23 opens. Thus, the operate check valve 23 is installed in the discharge passage P3.

[0028] Furthermore, when the outer rotor 3 is inserted into the pump chamber 7a1, the six ports 3c and the six passages 2a provided in the case 2 communicate with each other in pairs, and each passage 2a communicates with the gap between the internal teeth 3a, 3a of the outer rotor 3. In addition, since long grooves 3d communicating with the ports 3c are formed along the circumferential direction on the outer circumference of the outer rotor 3, even if the outer rotor 3 rotates in the circumferential direction within the range in which the convex portion 3b is allowed to move within the recess 7a2, the communication between each port 3c and the corresponding passage 2a is not interrupted.

[0029] The inner rotor 4 is annular in shape and has external teeth 4a on its outer circumference that mesh with the internal teeth 3a of the outer rotor 3. The shape of the external teeth 4a is a trochoidal curve tooth profile that meshes with the internal teeth 3a of the outer rotor 3, and the number of teeth of the external teeth 4a is one less than the number of teeth of the internal teeth 3a of the outer rotor 3. The shape of the external teeth 4a is not limited to a trochoidal curve tooth profile, as long as it matches the shape of the internal teeth 3a of the outer rotor 3.

[0030] The inner rotor 4 is rotatably inserted into the outer rotor 3, and when driven by the motor 6 (described later), it can revolve and rotate along the inner circumference of the outer rotor 3.

[0031] The motor 6 is fixed to the upper part of the case 2. Specifically, the motor 6 has an output shaft 6a that is inserted into a hole 8a1 provided in the motor holder 8a, and is fixed to the motor holder 8a of the lid 8 so that the rotation center of the output shaft 6a coincides with the center of the outer rotor 3 when viewed in the axial direction. The output shaft 6a is connected to the inner rotor 4 via a coupling 9. The coupling 9 has a substantially fan-shaped connecting plate 9a and a shaft 9b that extends downward toward the inner rotor 4 from a position eccentric from the center of the radius of the connecting plate 9a when viewed in the axial direction. The output shaft 6a is connected to an axis 9a1 provided at the center of the connecting plate 9a, and the motor 6 can rotate the coupling 9 in the circumferential direction around the axis 9a1.

[0032] The shaft 9b of the coupling 9 is slidably fitted to the inner circumference of the inner rotor 4. Therefore, the inner rotor 4 can rotate circumferentially around the shaft 9b. A bearing or bushing may be provided between the inner rotor 4 and the shaft 9b to allow the inner rotor 4 to rotate more smoothly circumferentially relative to the shaft 9b.

[0033] Thus, the output shaft 6a of the motor 6 is fixedly connected to the center of the connecting plate 9a, and the shaft 9b of the coupling 9 is connected to the center of the inner rotor 4 while allowing the inner rotor 4 to rotate.

[0034] Therefore, the center of rotation of the inner rotor 4 when it rotates is positioned offset in the axial direction from the output shaft 6a of the motor 6. When the motor 6 is driven and the coupling 9 rotates in the circumferential direction, the inner rotor 4 exhibits an orbital motion in which it rotates entirely within the outer rotor 3 along the inner circumference of the outer rotor 3, and also exhibits a rotational motion caused by the meshing of the internal teeth 3a and external teeth 4a of the outer rotor 3. In this embodiment, the power of the output shaft 6a of the motor 6 is transmitted to the inner rotor 4 via the coupling 9 to drive the inner rotor 4 to orbit and rotate, but the output shaft 6a may be made crank-shaped and connected directly to the inner rotor 4 without going through the coupling 9.

[0035] In Figure 2, the case where the inner rotor 4 revolves clockwise on one side relative to the outer rotor 3 is called forward rotation, and the case where the inner rotor 4 revolves counterclockwise on the other side relative to the outer rotor 3 is called reverse rotation. As shown in Figure 4, the meshing of the outer rotor 3 and the inner rotor 4 forms six cavities C1, C2, C3, C4, C5, and C6 between the outer rotor 3 and the inner rotor 4. Here, the uppermost cavity in Figure 4 is called cavity C1, and the cavities in clockwise order in Figure 4 are called cavities C2, C3...Cavity C6.

[0036] Then, as shown in Figure 4, we consider that the inner rotor 4 is driven by the motor 6 to rotate clockwise from the positional relationship shown in Figure 4(a) with respect to the outer rotor 3. When the inner rotor 4 is driven, the outer rotor 3 rotates circumferentially, as described above, but only within the range where movement within the recess 7a2 of the convex portion 3b is permitted. However, for the sake of simplicity, in Figure 4, the outer rotor 3 is treated as being immovable relative to the case 2.

[0037] When the inner rotor 4 revolves clockwise from the positional relationship shown in Figure 4(a) with respect to the outer rotor 3, the inner rotor 4 moves from the position shown in Figure 4(a) to Figure 4(b), and then to Figure 4(b). 4(c), Figure 4(d), Figure 4(e), Figure 4 The device operates by sequentially changing positions to those shown in (f), and eventually returning to the original position shown in Figure 4(a).

[0038] In the state shown in Figure 4(a), cavity C1 is in its most compressed state. When the inner rotor 4 revolves clockwise, it moves while rotating on its axis, and when it reaches the position shown in Figure 4(b), cavity C1 expands. The expansion of cavity C1 continues until the inner rotor 4 reaches the position shown in Figure 4(d), at which point the volume of cavity C1 is at its maximum. Furthermore, as the inner rotor 4 continues to revolve from the position shown in Figure 4(d), the volume of cavity C1 begins to decrease, and this decrease in cavity C1 continues until the inner rotor 4 returns to the position shown in Figure 4(a). In the state shown in Figure 4(a) where the inner rotor 4 is positioned, cavity C4, which is on the opposite side of the center of the outer rotor 3 from cavity C1, has the maximum volume. Therefore, it can be seen that cavities C2 and C3, located to the right of the imaginary line L that passes through the center of the outer rotor 3 and divides the outer rotor 3 into left and right halves, are in a discharge mode where the volume decreases as the inner rotor 4 revolves clockwise, while cavities C5 and C6, located to the left of the imaginary line L, are in a suction mode where the volume expands as the inner rotor 4 revolves clockwise.

[0039] Therefore, if the cavity in suction mode among the six cavities C1, C2, C3, C4, C5, and C6 is connected to the tank T via a suction passage P1 that opens above the pump chamber 7a1, the internal gear pump 1 can draw liquid from the tank T. If the cavity in discharge mode is blocked from the tank T, the liquid can be discharged to the reservoir chamber R via the port 3c, the long groove 3d, and the passage 2a.

[0040] Therefore, in the internal gear pump 1 of this embodiment, the connecting plate 9a in the coupling 9 connected to the output shaft 6a of the motor 6 closes the cavity in discharge mode. The connecting plate 9a slides against the upper surfaces of the outer rotor 3 and the inner rotor 4, closing off the upper part of the cavity in discharge mode to cut off communication with the suction passage P1, while leaving the cavity in suction mode open to allow communication with the tank T.

[0041] The following describes the connecting plate 9a in detail. When the inner rotor 4 is in the position shown in Figure 4(a), the three cavities C1, C2, and C3 are in discharge mode, and the remaining three cavities C4, C5, and C6 are in suction mode. Therefore, when the inner rotor 4 is in the position shown in Figure 4(a), the connecting plate 9a is required to isolate the three cavities C1, C2, and C3 from the tank T. Furthermore, the volume of cavity C3, which has the largest volume, begins to decrease if the inner rotor 4 is driven even slightly clockwise from the position shown in Figure 4(a). Therefore, if cavity C3 is blocked by the connecting plate 9a in the position shown in Figure 4(a), the communication between cavity C3 and the tank T will be severed as soon as the inner rotor 4 rotates clockwise from the position shown in Figure 4(a). In the internal gear pump 1 of this embodiment, the outer rotor 3 is equipped with six internal teeth 3a, forming six cavities C1, C2, C3, C4, C5, and C6. Therefore, as shown in Figure 4(a), the connecting plate 9a needs to cover a range of 30 degrees counterclockwise in the figure from the dotted line L to the center of the outer rotor 3 in order to close cavity C1. In addition, in the internal gear pump 1 of this embodiment, the connecting plate 9a covers a range of 29 degrees clockwise in the figure from the dotted line L to the center of the outer rotor 3 in order to quickly close cavity C3 as the inner rotor 4 revolves clockwise. Therefore, the connecting plate 9a is a fan shape with a central angle set to 239 degrees and a radius set to be greater than the length from the center of the outer rotor 3 to the inner circumference of the outer rotor 3 that is furthest from the center.

[0042] This is how it is configured difference The connecting plate 9a is connected to the output shaft 6a such that the center of its radius coincides with the center of the output shaft 6a of the motor 6. As it rotates with the revolution of the inner rotor 4, it can open the top of the cavity in suction mode among the six cavities C1, C2, C3, C4, C5, and C6 to communicate with the tank T, and close the top of the cavity in discharge mode to prevent liquid from escaping into the tank T.

[0043] Furthermore, the setting of the central angle of the connecting plate 9a can be modified according to the setting of the closing timing of the cavity with the maximum volume. Since the number of cavities changes depending on the number of teeth of the internal teeth 3a of the outer rotor 3, the design should be modified to suit that number of teeth.

[0044] As described above, when the internal gear pump 1 is driven by the motor 6 to revolve the inner rotor 4 around the outer rotor 3 in one direction clockwise in Figure 2, the inner rotor 4 revolves around the outer rotor 3 clockwise while rotating on its own axis counterclockwise. The connecting plate 9a opens the cavity in suction mode, allowing communication with the suction passage P1, and closes the cavity in discharge mode. Therefore, when the inner rotor 4 is rotated clockwise, the internal gear pump 1 draws liquid from the tank T into the cavity in suction mode via the suction passage P1 and discharges the liquid from the cavity in discharge mode. The liquid discharged from the discharge mode passes through port 3c and long groove 3d, opening the check valve 2b and being discharged into the reservoir chamber R via passage 2a. Therefore, when the internal gear pump 1 is rotating forward, it draws liquid from the tank T through the suction passage P1 and discharges it to the reservoir chamber R through the discharge passage P2, which consists of a port 3c, a long groove 3d, and a passage 2a. When the inner rotor 4 rotates clockwise, a clockwise torque acts on the outer rotor 3, which presses the valve body 23a of the operable check valve 23 in a direction that closes the discharge passage P3 with the protrusion 3b, thus blocking the discharge passage P3.

[0045] Furthermore, when the internal gear pump 1 drives the motor 6 to revolve the inner rotor 4 inside the outer rotor 3 in the reverse direction (counterclockwise in Figure 2), the inner rotor 4 pushes the outer rotor 3 counterclockwise, causing the protrusion 3b to compress the spring 23b of the operate check valve 23. The valve body 23a then retracts to the left in the recess 7a2 in Figure 2 due to the pressure inside the reservoir chamber R, opening the discharge passage P3. When the inner rotor 4 is driven counterclockwise, liquid cannot be drawn into the pump chamber 7a1 from either the reservoir chamber R or the tank T. However, since the rotation of the outer rotor 3 is permitted, the inner rotor 4 also revolves within the range of permitted rotation of the outer rotor 3. As long as the motor 6 is energized, the inner rotor 4 continues to push the outer rotor 3, so the operate check valve 23 remains open.

[0046] Next, the shock absorber body D will be described. The shock absorber body D comprises a cylinder 30, a piston 31 inserted into the cylinder 30 so as to be movable in the axial direction and dividing the inside of the cylinder 30 into an extension chamber R1 and a compression chamber R2, a piston rod 32 inserted into the extension chamber R1 and movable in the axial direction relative to the cylinder 30 and connected to the piston 31, an outer cylinder 33 covering the cylinder 30, a tank T and a reservoir chamber R formed by dividing the annular gap between the cylinder 30 and the outer cylinder 33 into upper and lower sections by the case 2 of the internal gear pump 1, a valve case 34 provided at the lower end of the cylinder 30 and dividing the reservoir chamber R and the compression chamber R2, an upper spring receiver 40 provided at the upper end of the piston rod 32, and a lower spring receiver 41 provided above the case 2 of the outer cylinder 33.

[0047] An annular rod guide 35 is fitted to the upper end of the cylinder 30, into which a piston rod 32 is slidably inserted. Above the rod guide 35 in Figure 1, a cap 36 is fitted, which is attached to the inner circumference of the upper end of the outer cylinder 33. The cap 36 comprises an annular sealing member 36a that seals the outer circumference of the piston rod 32 and an annular sealing member 36b that is in close contact with the inner circumference of the upper end of the outer cylinder 33, thereby sealing the upper ends of the cylinder 30 and the outer cylinder 33. A valve case 34 is fitted to the lower end of the cylinder 30. The piston rod 32 is inserted through the inner circumference of the rod guide 35 and the cap 36, with its lower end connected to the piston 31 and its upper end protruding above the cylinder 30, and is inserted along the entire axial length of the extension chamber R1, but is not inserted into the compression chamber R2. A portion of the lower end of the piston rod 32 may be inserted into the compression chamber R2, but the piston rod 32 is not inserted along the entire axial length of the compression chamber R2. In addition, an end bolt 32a is provided at the upper end of the piston rod 32 to enable attachment to the vehicle body, and an annular upper spring support 40 is attached to the outer circumference near the upper end.

[0048] Furthermore, the case 2 of the internal gear pump 1 is fitted to the outer circumference of the middle section of the cylinder 30. Specifically, the outer circumference of the cylinder 30 is fitted to the inner circumference of the mounting portions 7b and 8b of the case body 7 and lid 8 of the case 2. Outside the diagram Seallin Gu The case 2 and cylinder 30 are sealed by being in close contact with the outer circumference of the cylinder 30.

[0049] The outer cylinder 33 comprises an upper cylinder 33a and a lower cylinder 33b. A cap 36 is attached to the upper end of the upper cylinder 33a, and the lower end of the upper cylinder 33a is welded to a mounting portion 8b of the lid 8 on the case 2 which fits onto the outer circumference of the cylinder 30. The lower cylinder 33b is closed at its lower end by a bottom cap 37 with a bracket 37a that allows mounting to a vehicle (not shown), and its upper end is attached to a mounting portion on the case body 7. 7b They are joined together by welding.

[0050] Thus, the annular gap between the outer cylinder 33 and the cylinder 30 is divided vertically by the case 2, and a tank T is formed in the annular gap between the upper cylinder 33a, which covers the upper side of the cylinder 30, and the cylinder 30, while a reservoir chamber R is formed in the annular gap between the lower cylinder 33b, which covers the lower side of the cylinder 30, and the cylinder 30.

[0051] Tank T is filled with both liquid and gas. The gas filling tank T is preferably an inert gas such as nitrogen, but it may also be air or another gas.

[0052] Furthermore, a cylindrical bladder 38 is housed within the reservoir chamber R. The upper and lower ends of the bladder 38 are secured by annular retaining rings 39a and 39b, respectively. Lower tube 33b The bladder 38 is sandwiched between the two, and divides the reservoir chamber R into an air chamber RG filled with gas and a liquid chamber RL filled with liquid. Compressed gas is sealed inside the air chamber RG separated by the bladder 38, constantly pressurizing the reservoir chamber R.

[0053] Furthermore, an annular lower spring support 41 is attached to the outer circumference of the upper cylinder 33a. Between the upper spring support 40 provided at the upper end of the piston rod 32 and the lower spring support 41 provided on the outer circumference of the upper cylinder 33a, a suspension spring S, which consists of a coil spring arranged on the outer circumference of the piston rod 32, is interposed. Therefore, when the shock absorber SA with ride height adjustment function is interposed between the vehicle body and the wheels, the vehicle body is elastically supported by the suspension spring S.

[0054] The piston 31 is slidably inserted into the cylinder 30 and is movable in the vertical direction in Figure 1, which is axial with respect to the cylinder 30, and divides the inside of the cylinder 30 into an extension chamber R1 and a compression chamber R2. The piston 31 also includes an extension damping passage 31a and a compression passage 31b that connect the extension chamber R1 and the compression chamber R2, an extension damping valve 31c provided in the extension damping passage 31a that allows only the flow of liquid from the extension chamber R1 to the compression chamber R2 and provides resistance to the liquid flow, and a compression check valve 31d provided in the compression passage 31b that allows only the flow of liquid from the compression chamber R2 to the extension chamber R1.

[0055] The valve case 34 is fitted to the lower end of the cylinder 30 and, together with the cylinder 30 and the rod guide 35, is held in place by a cap 36 and a bottom cap 37 mounted on the outer cylinder 33, and is fixed immovably within the outer cylinder 33. The valve case 34 also partitions the pressure chamber R2 within the cylinder 30 and the liquid chamber RL within the reservoir chamber R. The valve case 34 also includes a pressure-side damping passage 34a and an extension-side suction passage 34b that connect the pressure-side chamber R2 and the reservoir chamber R, a pressure-side damping valve 34c provided in the pressure-side damping passage 34a that allows only the flow of liquid from the pressure-side chamber R2 to the reservoir chamber R and provides resistance to the liquid flow, and an extension-side check valve 34d provided in the extension-side suction passage 34b that allows only the flow of liquid from the reservoir chamber R to the pressure-side chamber R2.

[0056] As described above, the internal gear pump 1 of this embodiment is mounted on the shock absorber body D and together with the shock absorber body D constitutes a shock absorber SA with a ride height adjustment function. Next, the operation of the shock absorber SA with a ride height adjustment function will be explained. First, the operation of the shock absorber SA with a ride height adjustment function when the piston 31 moves upward relative to the cylinder 30 in Figure 1 will be explained. When the piston 31 moves upward relative to the cylinder 30, the extension chamber R1 is compressed, so the liquid moves from the extension chamber R1 to the expanding compression chamber R2 via the extension damping passage 31a and the extension damping valve 31c. As the liquid passes through the extension damping valve 31c, resistance is applied, causing the pressure in the extension chamber R1 to rise. When the shock absorber SA with ride height adjustment function extends, the piston rod 32 retracts from the cylinder 30, and the volume of liquid flowing from the extension chamber R1 into the compression chamber R2 is insufficient to match the volume of expansion in the compression chamber R2. Therefore, the extension check valve 34d opens, and the insufficient liquid is supplied from the reservoir chamber R to the compression chamber R2 via the extension suction passage 34b and the extension check valve 34d. In this way, the reservoir chamber R compensates for the volume of the piston rod 32 retracting from the cylinder 30. When the shock absorber SA with ride height adjustment function extends, the pressure in the extension chamber R1 increases while the pressure in the compression chamber R2 becomes approximately equal to the pressure in the reservoir chamber R. This pressure difference between the extension chamber R1 and the compression chamber R2 generates a damping force that hinders the extension of the shock absorber body D.

[0057] On the other hand, when the shock absorber SA with ride height adjustment function is contracted, the piston 31 moves downward in Figure 1 relative to the cylinder 30, the compression chamber R2 is compressed, and the liquid moves from the compression chamber R2 to the expanding extension chamber R1 via the compression passage 31b and the compression check valve 31d. Since the compression check valve 31d does not provide much resistance to the liquid flow, when the shock absorber SA with ride height adjustment function is contracted, the pressures in the compression chamber R2 and the extension chamber R1 become approximately equal. Also, when the shock absorber SA with ride height adjustment function is contracted, the piston rod 32 enters the cylinder 30, so there is an excess of liquid in the cylinder 30 equal to the volume of the piston rod 32 entering the cylinder 30, and this excess liquid moves to the reservoir chamber R via the compression damping passage 34a and the compression damping valve 34c. In this way, the reservoir chamber R compensates for the volume of the piston rod 32 entering the cylinder 30. Furthermore, the compression damping valve 34c resists the flow of fluid, causing the pressure inside the cylinder 30 to rise. As a result, the pressure-receiving area of ​​the piston 31 facing the compression chamber R2 is larger than the pressure-receiving area of ​​the piston 31 facing the extension chamber R1 by the cross-sectional integral of the piston rod 32. Therefore, the shock absorber SA with ride height adjustment function generates a damping force that prevents the shock absorber body D from contracting.

[0058] Next, we will explain the operation of the shock absorber SA with ride height adjustment function when the internal gear pump 1 is driven to adjust the ride height. First, as mentioned above, the reservoir chamber R is pressurized by compressed gas sealed in the bladder 38, and the pressure in the reservoir chamber R is transmitted into the cylinder 30 through the extension-side suction passage 34b and the compression-side passage 31b. When the shock absorber SA with ride height adjustment function is stationary, the pressure in the cylinder 30 is approximately the same as the pressure in the reservoir chamber R. In other words, the inside of the cylinder 30 is also constantly pressurized by compressed gas sealed in the bladder 38.

[0059] The pressure in the compression chamber R2 acts to push the piston 31 upward in Figure 1, and the pressure in the extension chamber R1 acts to push the piston 31 downward in Figure 1. As mentioned above, the pressure-receiving area of ​​the piston 31 that receives the pressure in the compression chamber R2 is larger than the pressure-receiving area of ​​the piston 31 that receives the pressure in the extension chamber R1 by the cross-sectional integral of the piston rod 32. Therefore, the piston 31 is constantly biased upward in Figure 1 by a force equal to the pressure in the cylinder 30 multiplied by the cross-sectional area of ​​the piston rod 32. Since this force that biases the piston 31 upward in Figure 1 is proportional to the pressure in the cylinder 30, driving the internal gear pump 1 to supply liquid to the cylinder 30 through the reservoir chamber R will increase the pressure in the cylinder 30, thereby increasing the force that biases the piston 31 upward and extending the buffer body D.

[0060] When the internal gear pump 1 is driven by the motor 6 so that the inner rotor 4 rotates clockwise relative to the outer rotor 3 in Figure 2, it draws liquid from the tank T through the suction passage P1 and discharges the liquid to the reservoir chamber R through the discharge passage P2. As the liquid supplied by the internal gear pump 1 increases the pressure in the reservoir chamber R, the extension check valve 34d opens and liquid is supplied from the reservoir chamber R to the compression chamber R2. Furthermore, as the inflow of liquid into the compression chamber R2 pushes the piston 31 upward, the extension damping valve 31c opens from the extension chamber R1, whose volume is decreasing, and liquid moves from the extension chamber R1 to the compression chamber R2 through the extension damping passage 31a. Therefore, when the internal gear pump 1 is driven to supply liquid from the tank T to the reservoir chamber R, the pressure in the reservoir chamber R and the cylinder 30 rises approximately equally. After the vehicle height reaches the desired height due to the increase in pressure within cylinder 30, stopping the internal gear pump 1 will cause the check valve 2b to close, maintaining the fluid levels in the reservoir chamber R and cylinder 30, thus maintaining the vehicle height.

[0061] Conversely to the above, if liquid is discharged from the reservoir chamber R to the tank T, the pressure inside the cylinder 30 decreases, which reduces the force biasing the piston 31 upward and can lower the vehicle height.

[0062] When the shock absorber body D is contracted, the motor 6 drives the inner rotor 4 counterclockwise relative to the outer rotor 3 in Figure 2, thereby adding torque to rotate the outer rotor 3 counterclockwise. While the check valve 2b is closed when the inner rotor 4 rotates counterclockwise, the spring 23b is compressed by the protrusion 3b as the outer rotor 3 rotates counterclockwise, causing the valve body 23a to open the discharge passage P3. When the operated check valve 23 opens in this way, the reservoir chamber R and the tank T are connected via the discharge passage P3, and liquid moves from the reservoir chamber R to the tank T.

[0063] As liquid moves from reservoir chamber R to tank T, the pressure in reservoir chamber R decreases, causing the compression damping valve 34c to open and liquid to move from compression chamber R2 to reservoir chamber R. Furthermore, the decrease in liquid in compression chamber R2 causes the extension damping valve 31c to open and liquid to move from extension chamber R1 to compression chamber R2. Therefore, when the internal gear pump 1 is driven to discharge liquid from reservoir chamber R to tank T, the pressure in reservoir chamber R and cylinder 30 decreases approximately equally. After the vehicle height reaches the desired height, when the power to motor 6 is stopped, the torque of motor 6 that rotates the outer rotor 3 counterclockwise via inner rotor 4 disappears, so the biasing force of spring 23b acts on valve body 23a via protrusion 3b, causing valve body 23a to block the discharge passage P3. Therefore, when power to the motor 6 is stopped, the operable check valve 23 closes, cutting off communication between the reservoir chamber R and the tank T through the discharge passage P3, and the check valve 2b is also kept closed, thus maintaining the amount of fluid in the reservoir chamber R and the cylinder 30, and thus maintaining the vehicle height.

[0064] Furthermore, if the pressure in the reservoir chamber R becomes excessive due to the contraction of the buffer body D or the supply of liquid from the internal gear pump 1 to the reservoir chamber R, the relief valve 24 opens, releasing the liquid from the reservoir chamber R to the tank T via the relief passage P4, thereby preventing the pressure in the reservoir chamber R from becoming excessive and preventing liquid leakage from the buffer body D.

[0065] As described above, the internal gear pump 1 of this embodiment is characterized by comprising a case 2 having a pump chamber 7a1, an annular outer rotor 3 having internal teeth 3a on its inner circumference and housed in the pump chamber 7a1, an inner rotor 4 housed in the pump chamber 7a1 and inserted into the inner circumference side of the outer rotor 3 and having external teeth 4a that mesh with the outer rotor 3, and a motor 6 that drives the inner rotor 4 to revolve and rotate within the outer rotor 3.

[0066] In the internal gear pump 1 configured as described above, the outer rotor 3 does not rotate when the inner rotor 4 revolves and rotates to discharge liquid. Therefore, frictional force is generated at only two points during liquid discharge: between the outer rotor 3 and the inner rotor 4, and between the inner rotor 4 and the case 2. This reduces the number of friction points compared to conventional internal gear pumps. Thus, according to the internal gear pump 1 of this embodiment, liquid of Because the frictional resistance during discharge can be reduced, losses can be reduced and pump efficiency can be improved compared to conventional internal gear pumps.

[0067] Furthermore, the internal gear pump 1 of this embodiment reduces frictional resistance during operation, thereby reducing the torque required for the motor 6 that drives the inner rotor 4, and allowing the motor 6 to be miniaturized. In addition, because the motor 6 can be miniaturized in the internal gear pump 1 of this embodiment, the motor 6 does not get in the way even when it is integrated with equipment that receives liquid from the internal gear pump 1 to form a hydraulic device, thus improving ease of mounting on equipment and allowing for miniaturization of the hydraulic device.

[0068] Furthermore, the internal gear pump 1 of this embodiment is equipped with an operateable check valve 23 that opens and closes a discharge passage P3 provided in the case 2 and connecting the high-pressure side and the low-pressure side separated by the case 2. The operateable check valve 23 can be switched between open and closed states depending on the direction of torque applied to the outer rotor 3, closing when the inner rotor 4 revolves in one direction and opening when the inner rotor 4 revolves in the other direction. In the internal gear pump 1 configured in this way, the torque transmitted from the motor 6 to the outer rotor 3 via the inner rotor 4 is used to open the operateable check valve 23. Close Therefore, no other drive source is needed besides motor 6, which reduces manufacturing costs.

[0069] In the internal gear pump 1 of this embodiment, the operate check valve 23 includes a recess 7a2 that opens into a pump chamber 7a1 provided in the case 2, a protrusion 3b provided on the outer rotor 3 and inserted into the recess 7a2, a valve body 23a housed in the recess 7a2 on one side in the circumferential direction relative to the protrusion 3b and opening and closing the discharge passage P3, and a spring 23b housed in the recess 7a2 on the other side in the circumferential direction relative to the protrusion 3b and biasing the valve body 23a in the direction of closing the discharge passage P3 via the protrusion 3b.

[0070] With the internal gear pump 1 configured in this way, an operable check valve 23 that opens and closes by transmitting the torque of the motor 6 to the outer rotor 3 via the inner rotor 4 can be realized with a simple configuration. Furthermore, since a protrusion 3b is provided on the outer rotor 3 and the biasing force of the spring 23b acts on the valve body 23a via the protrusion 3b, the discharge passage P3 can be blocked by the valve body 23a even if there is an error in the position of the opening of the passage P3a. In this embodiment of the internal gear pump 1, the protrusion 3b is provided on the outer circumference of the outer rotor 3, but as long as it can constitute the operable check valve 23 together with the valve body 23a and the spring 23b, it may be provided so as to protrude axially from the axial end of the outer rotor 3 according to the position of the recess 7a2 provided on the case 2. In addition, although highly accurate dimensional control is required, the valve body 23a may be integrated with the protrusion 3b and the function of the valve body may be concentrated on the protrusion 3b.

[0071] In addition to the configuration described above, the operate check valve may also be configured as described below. As shown in Figure 5, the operate check valve 231 may be configured to include a protrusion 3b provided on the outer circumference or side of the outer rotor 3, a pin 231a facing the protrusion 3b, a valve body 231b that opens and closes a discharge passage P3 provided in the case 2, and a leaf spring 231c that biases the valve body 231b in the direction of closing the discharge passage P3. The pin 231a is provided in the case 2 so as to be movable in the left-right direction in Figure 5. The leaf spring 231c has one end fixed to the case 2, and its middle portion is in contact with the valve body 231b, biasing the valve body 231b toward the opening of the passage that forms the discharge passage P3, and has a bent portion 231c1 on the other end. The bent portion 231c1 is in contact with the tip of the pin 231a. When the inner rotor 4 is driven counterclockwise, the protrusion 3b of the outer rotor 3 pushes the pin 231a to the left in Figure 5, causing it to penetrate the bent portion 231c1 of the leaf spring 231c downwards in Figure 5, and the leaf spring 231c bends in a direction away from the opening. When the leaf spring 231c bends in this way, the valve body 231b can move away from the opening, thus opening the discharge passage P3 and opening the operate check valve 231. When the inner rotor 4 is driven clockwise to one side from the open position of the operate check valve 231, the outer rotor 3 returns to the position shown in Figure 5, and the deflected leaf spring 231c returns to its original position by its own elastic force, causing the pin 231a to retract toward the protrusion 3b and re-energizing the valve body 231b to close the discharge passage P3, thereby closing the operate check valve 231.

[0072] The operate check valve 232 may also be configured as shown in Figure 6. The operate check valve 232 shown in Figure 6 comprises a recess 3e provided on the outer circumference or side of the outer rotor 3, a valve body 232a that opens and closes the discharge passage P3, and a spool 232b, one end of which is inserted into the recess 3e and the other end of which abuts against the valve body 232a. The recess 3e has different depths in the circumferential direction of the outer rotor 3, comprising a first portion 3e1 which is deeper, a second portion 3e2 which is shallower than the first portion 3e1, and an inclined portion 3e3 with a sloped bottom surface that connects the first portion 3e1 and the second portion 3e2.

[0073] discharge passage P3 In the middle of the spool, there is a valve seat 232c on which a spherical valve body 232a can be seated and detached. The total length of the spool 232b is set such that when one end is inserted into the deep first portion 3e1, it does not come into contact with the valve body 232a seated on the valve seat 232c, and when one end is inserted into the shallow second portion 3e2, it pushes the valve body 232a seated on the valve seat 232c and separates it from the valve seat 232c.

[0074] In the operated check valve 232 configured in this way, when the motor 6 is driven to drive the inner rotor 4 in the opposite direction, counterclockwise, the outer rotor 3 moves in the direction shown in Figure 6 due to torque transmission. left As it rotates in that direction, one end of the spool 232b enters the shallower second section 3e2 and the spool 232b moves in Figure 6 aboveThe inner rotor 4 moves in one direction, separating the valve body 232a from the valve seat 232c. Therefore, when the inner rotor 4 is driven in the other direction, counterclockwise, the valve body 232a separates from the valve seat 232c, the operate check valve 232 opens, and the discharge passage P3 is opened. On the other hand, when the motor 6 is driven from the state in which the operate check valve 232 is open to drive the inner rotor 4 in the other direction, the outer rotor 3 returns to the position shown in Figure 6 due to torque transmission, one end of the spool 232b enters the deeper first portion 3e1, and the spool 232b separates from the valve body 232a, so the valve body 232a receives pressure on the high-pressure side and seats on the valve seat 232c. Therefore, when the inner rotor 4 is driven in one direction, the valve body 232a seats on the valve seat 232c, the operate check valve 232 closes, and the discharge passage P3 is blocked.

[0075] Thus, the operable check valves 23, 231, and 232 can be opened and closed using the torque transmitted to the outer rotor 3 via the inner rotor 4, and their configuration can be appropriately modified. In the above description, since liquid is discharged when the inner rotor 4 revolves clockwise, the clockwise direction of the inner rotor 4 is designated as one side and the counterclockwise direction of the inner rotor 4 is designated as the other side. However, if liquid is discharged when the inner rotor 4 revolves counterclockwise, the counterclockwise direction of the inner rotor 4 may be designated as one side and the clockwise direction of the inner rotor 4 is designated as the other side.

[0076] Furthermore, the internal gear pump 1 of this embodiment takes in liquid from the vertical direction, which is the axial direction of the outer rotor 3, into a plurality of cavities C1, C2, C3, C4, C5, C6 formed between the outer rotor 3 and the inner rotor 4, and discharges the liquid through a plurality of ports 3c that connect the inner and outer circumferences of the outer rotor 3 and lead to each of the cavities C1, C2, C3, C4, C5, C6. With the internal gear pump 1 configured in this way, liquid can be discharged from the side of the outer rotor 3, so the vertical height of the case 2 can be shortened compared to the case 2 in which the discharge port is provided vertically.Therefore, with the internal gear pump 1 of this embodiment, the overall height of the internal gear pump 1 can be made compact, and even when the internal gear pump 1 is integrated with equipment that receives liquid from the equipment to constitute a hydraulic device, the mountability on the equipment is improved and the hydraulic device can be made smaller.

[0077] In this embodiment, the internal gear pump 1 is provided with a check valve 2b in a passage 2a that forms part of the discharge passage P2 in the case 2, which allows only the flow of liquid from the pump chamber 7a1 to the reservoir chamber R. However, a check valve may also be provided in the middle of the port 3c of the outer rotor 3. Furthermore, instead of providing the port 3c and long groove 3d in the outer rotor 3, the check valve 49 may be configured with a valve case 50 stacked below the outer rotor 3 and a valve body 51 mounted in the valve case 50, as shown in Figure 7. The valve case 50 is annular and has an annular recess 50a in the center, six recesses 50b that are connected to the outer circumference of the annular recess 50a and, when stacked on the outer rotor 3, face each cavity C1, C2, C3, C4, C5, C6, and six holes 50c that penetrate the thickness of the valve case 50 and open into the recesses 50b. Then, when the valve case 50 is stacked on the outer rotor 3 with the side without the annular recesses 50a and 50b facing the outer rotor 3, each recess 50b communicates with the corresponding cavities C1, C2, C3, C4, C5, and C6 via the holes 50c. The valve body 51 comprises an annular portion 51a that is inserted into the annular recess 50a and a valve portion 51b provided on the outer circumference of the annular portion 51a that is inserted into each recess 50b and opens and closes the holes 50c, and its inner circumference is fixed to the valve case 50 by a fixed shaft (not shown). In this case, a discharge passage is formed in the case 2 so that the bottom of the pump chamber 7a1 communicates with the reservoir chamber R. In the check valve 49 configured in this way, the valve case 50 acts as a valve seat, allowing the valve portion 51b to flex. Liquid discharged from cavities C1, C2, C3, C4, C5, and C6 can pass through the corresponding holes 50c, pushing open the valve portion 51b, and move through the recess 50b to the reservoir chamber R via a discharge passage provided in case 2. If the pressure inside the reservoir chamber R is higher than that inside cavities C1, C2, C3, C4, C5, and C6, the valve portion 51b is pressed against the bottom of the recess 50b in the valve case 50, preventing the hole 50c from opening and thus preventing the liquid from moving from the reservoir chamber R side into cavities C1, C2, C3, C4, C5, and C6.Thus, the check valve in the discharge passage P2 may be provided in the case 2, in the outer rotor 3, or even in the case 2.

[0078] Furthermore, the shock absorber SA with ride height adjustment function of this embodiment comprises a shock absorber body D having a cylinder 30, a piston 31 inserted into the cylinder 30 so as to be movable in the axial direction and dividing the inside of the cylinder 30 into an extension chamber R1 and a compression chamber R2, a piston rod 32 inserted into the extension chamber R1 so as to be movable in the axial direction relative to the cylinder 30 and connected to the piston 31, and an outer cylinder 33 covering the cylinder 30, and an internal gear pump 1. The case 2 divides the annular gap between the cylinder 30 and the outer cylinder 33 into a tank T which is a low-pressure side for storing liquid and a reservoir chamber R which is a high-pressure side that is in communication with the compression chamber R2 and compensates for the volume by which the piston rod 32 moves in and out of the cylinder 30.

[0079] In the shock absorber SA with ride height adjustment function configured in this way, damping force is exerted during expansion and contraction to suppress vibrations of the vehicle body. Furthermore, by driving the internal gear pump 1 to discharge liquid from the tank T to the reservoir chamber R, the shock absorber body D can be extended to raise the ride height, and by using the internal gear pump 1 to discharge liquid from the reservoir chamber R to the tank T, the shock absorber body D can be contracted to lower the ride height. In addition, since the internal gear pump 1 separates the tank T and the reservoir chamber R with the case 2, the pump part can be placed close to the shock absorber body D, and the suction passage P1 and discharge passage P2 that supply liquid from the tank T to the reservoir chamber R, and the discharge passage P3 that discharges liquid from the reservoir chamber R to the tank T can be consolidated into the case 2 and simplified. Therefore, the shock absorber SA with ride height adjustment function can be miniaturized even with the internal gear pump 1, and manufacturing costs can be reduced. Furthermore, in the shock absorber SA with ride height adjustment function configured in this way, the internal gear pump 1 is mounted in the middle part of the cylinder 30 above the lower end of the cylinder 30, so that the motor 6 can be protected from flying stones while the vehicle is in motion and from water splashes when driving on flooded roads.

[0080] In this embodiment, the device to which the internal gear pump 1 is applied is the buffer body D. However, any device that can receive liquid from the internal gear pump 1 is acceptable, so it may be applied to devices other than the buffer body D, such as hydraulic jacks or actuators. Furthermore, in this embodiment, the structure of the internal gear pump 1 is explained using an example in which the internal gear pump 1 is integrated into the buffer body (device) D. However, if integration into the device is not necessary, the mounting portion 7b of the case body 7 and the mounting portion 8b of the lid 8 in the case 2 may be omitted.

[0081] Although preferred embodiments of the present invention have been described in detail above, modifications, alterations, and changes are permitted as long as they do not deviate from the scope of the claims. [Explanation of Symbols]

[0082] 1...Internal gear pump, 2...Case, 3...Outer rotor, 3a...Internal gear 、4 ...Inner rotor, 4a...external teeth, 6...Motor, 30...Cylinder, 31...Piston, 32...Piston rod, 33...Outer cylinder, D...Shock absorber body (equipment), SA...Shock absorber with ride height adjustment function, T...Tank

Claims

1. Cases with a pump room, An annular outer rotor having internal teeth on its inner circumference, which is housed in the pump chamber, An inner rotor housed in the pump chamber and inserted into the inner circumference of the outer rotor, having external teeth that mesh with the outer rotor, A motor that drives the inner rotor to revolve and rotate within the outer rotor, The case is provided with an operable check valve that opens and closes a passage connecting the high-pressure side and the low-pressure side, which are separated by the case. The operable check valve is switchable between open and closed states depending on the direction of torque applied to the outer rotor, closing when the inner rotor revolves in one direction and opening when the inner rotor revolves in the other direction. An internal gear pump characterized by the following features.

2. A shock absorber body having a cylinder, a piston inserted into the cylinder so as to be movable in the axial direction and dividing the inside of the cylinder into an extension chamber and a compression chamber, a piston rod inserted into the extension chamber so as to be movable in the axial direction relative to the cylinder and connected to the piston, and an outer cylinder covering the cylinder, An internal gear pump comprising a case having a pump chamber, an annular outer rotor having internal teeth on its inner circumference and housed in the pump chamber, an inner rotor housed in the pump chamber and inserted into the inner circumference side of the outer rotor and having external teeth that mesh with the outer rotor, and a motor that drives the inner rotor to revolve and rotate within the outer rotor, In the aforementioned case, the annular gap between the cylinder and the outer cylinder is divided into a tank for storing liquid and a reservoir chamber that communicates with the pressure side chamber and compensates for the volume through which the piston rod moves in and out of the cylinder. A shock absorber with ride height adjustment function, characterized by the following features.

3. Liquid is drawn into multiple cavities formed between the outer rotor and the inner rotor from the vertical direction in the axial direction of the outer rotor, and the liquid is discharged through multiple ports that connect the inner and outer circumferences of the outer rotor and lead to each cavity. The internal gear pump according to feature 1.

Images