shock absorber with ride height adjustment function

Abstract

To provide an internal gear pump capable of reducing the size of a motor, and a liquid pressure device and a buffer with a vehicle height adjustment function that can be downsized even when comprising the internal gear pump.SOLUTION: An internal gear pump 1 in the present invention includes: a case 2; an outer rotor 3 that is annular, has internal teeth 3a provided on an inner periphery and external teeth 3b provided on an outer periphery, and is rotatably housed in the case 2 in a circumferential direction; an inner rotor 4 that is housed in the case 2, and is an external gear that is inserted into the inner peripheral side of the outer rotor 3 and meshes with the outer rotor 3; a driving gear 5 meshing with the external teeth 3b of the outer rotor 3; and a motor 6 that drives the driving gear. The number of teeth of the driving gear 5 is smaller than the number of teeth of the external teeth 3b of the outer rotor 3.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention ,car relates to a shock absorber with a high adjustment function.

Background Art

[0002] An internal gear pump includes a case, an outer rotor which is an internal gear and is circumferentially rotatably accommodated in the case, an inner rotor which is an external gear accommodated in the case and inserted into the inner circumferential side of the outer rotor to mesh 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] 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

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, there are limitations on the combination of the number of teeth on the outer teeth of the inner rotor and the number of teeth on the inner teeth of the outer rotor, making it difficult to increase the reduction ratio. Therefore, a large torque output is required for the motor that drives the inner rotor. Consequently, it is difficult to miniaturize the motor in conventional internal gear pumps.

[0007] Furthermore, in hydraulic systems where an internal gear pump is integrated into the equipment, miniaturization of the motor is difficult, which hinders the attachment of the internal gear pump to the equipment, making it difficult to miniaturize the entire hydraulic system.

[0008] Furthermore, some shock absorbers with ride height adjustment capabilities allow for ride height adjustment by supplying and discharging liquid into and out of a cylinder from an internal gear pump, thereby expanding and contracting the shock absorber body. However, miniaturizing the motor is difficult, so the motor gets in the way of attaching the internal gear pump to the shock absorber body, making it difficult to miniaturize the entire shock absorber with ride height adjustment capability.

[0009] Therefore, the present invention provides an internal gear pump that enables miniaturization of motors. Pu Even with these features, miniaturization is possible. car The aim is to provide shock absorbers with high adjustment capabilities. [Means for solving the problem]

[0010] To solve the aforementioned problem, the internal gear pump in the problem-solving means of the present invention comprises a case, an annular outer rotor having internal teeth on its inner circumference and external teeth on its outer circumference and rotatably housed in the case in the circumferential direction, an inner rotor housed in the case and inserted into the inner circumference side of the outer rotor and meshing with the outer rotor with an external gear, a drive gear meshing with the external teeth of the outer rotor, and a motor that drives the drive gear, characterized in that the number of teeth of the drive gear is less than the number of teeth of the external teeth of the outer rotor.

[0011] In this configuration, the internal gear pump uses a drive gear and the outer rotor to form a reduction gear to drive the outer rotor and inner rotor. Because the torque required to drive the drive gear to drive the outer rotor and inner rotor is small, the motor can be made smaller. Furthermore, because the motor can be made smaller in an internal gear pump, the motor does not get in the way when it is integrated into equipment that receives liquid from the internal gear pump to form a hydraulic device. This improves the ease of mounting on equipment and also allows for the miniaturization of the hydraulic device.

[0012] Furthermore, since the inner rotor, outer rotor, and drive gears are housed within the case, and the pump and reduction gear are integrated into a single structure, the internal gear pump can be made more compact.

[0013] Furthermore, the system may include an internal gear pump and a device integrated into the case that receives the supply and discharge of liquid from the internal gear pump, and the device may be cylindrical in shape. In this way, even if the device that receives the liquid supply from the internal gear pump is cylindrical, the motor directly drives the drive gear located on the outer circumference of the outer rotor. Therefore, even if the pump portion, which consists of the outer rotor and inner rotor of the internal gear pump, is placed very close to the device, the motor, which is coaxial with the drive gear, can be easily positioned in a location that does not interfere with the device.

[0014] Furthermore, the shock absorber with ride height adjustment function comprises 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, and an internal gear pump whose case is connected to the outer cylinder and supplies and discharges liquid into and out of the cylinder, wherein when the outer cylinder is viewed from the axial direction, a part of the outer rotor is positioned inward from the outer circumference of the outer cylinder. With a shock absorber with ride height adjustment function configured in this way, since a part of the outer rotor is positioned inward from the outer circumference of the outer cylinder, the pump part of the internal gear pump can be positioned very close to the shock absorber body, and the overall outer diameter including the internal gear pump can be made even smaller. [Effects of the Invention]

[0015] According to the shock absorber with a vehicle height adjustment function of the present invention, even if it has a vehicle height adjustment function, it can be miniaturized.

Brief Description of the Drawings

[0016] [Figure 1] It is a longitudinal sectional view of a shock absorber with a vehicle height adjustment function to which an internal gear pump of an embodiment is applied. [Figure 2] It is a plan view of a case body in an internal gear pump of an embodiment. [Figure 3] It is a bottom view of a lid of a case in an internal gear pump of an embodiment. [Figure 4] It is a sectional view of a case body in an internal gear pump of an embodiment. [Figure 5] It is a partial sectional view of a check valve portion of a case body in an internal gear pump of an embodiment. [Figure 6] There is a partial sectional view of a check valve portion of a case body in an internal gear pump of an embodiment. [Figure 7] It is a partial sectional view of an operate check valve portion of a case body in an internal gear pump of an embodiment. [Figure 8] It is a partial sectional view of a relief valve portion of a case body in an internal gear pump of 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 includes, as shown in FIGS. 1 to 4, a case 2, an outer rotor 3 that is annular and has internal teeth 3a provided on its inner circumference and external teeth 3b provided on its outer circumference and is rotatably accommodated in the case 2 in the circumferential direction, an inner rotor 4 that is accommodated in the case 2 and is an external gear inserted into the inner circumferential side of the outer rotor 3 and meshes with the outer rotor 3, a driving gear 5 that meshes with the external teeth 3b of the outer rotor 3, and a motor 6 that drives the driving gear 5. Further, as shown in FIG. 1, the internal gear pump 1 of the present embodiment is integrally attached to the shock absorber body D 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 that houses the outer rotor 3, the inner rotor 4, and the driving gear 5, and a lid 8 that is stacked on the case body 7.

[0019] In the present embodiment, the case body 7 includes a pump portion 7a having a pump chamber 7a1 that is a circular recess for housing the outer rotor 3 and the inner rotor 4 inside, a gear housing portion 7b having a gear chamber 7b1 that is a circular recess for housing the driving gear 5 and connected to the side of the pump portion 7a, and an annular attachment portion 7c that is connected to the shock absorber body D to be described later and is connected to the side of the pump portion 7a.

[0020] In the present embodiment, as shown in FIGS. 1 and 2, in a plan view, the pump portion 7a, the gear housing portion 7b, and the attachment portion 7c all have a substantially circular outer peripheral shape, but the outer peripheral shape can be arbitrarily designed and changed.

[0021] Further, the pump chamber 7a1 in the pump portion 7a and the gear chamber 7b1 in the gear housing portion 7b are communicated with each other and have a shape formed by overlapping a part of two circles in a plan view.

[0022] As mentioned above, the shape of the pump chamber 7a1 in plan view is circular, and the diameter of the pump chamber 7a1 is set to a diameter that allows the tips of the external teeth 3b of the outer rotor 3 to slide against it, but does not hinder the circumferential rotation of the outer rotor 3 within the pump chamber 7a1. The shape of the gear chamber 7b1 is also circular, similar to the pump chamber 7a1, and the inner diameter of the gear chamber 7b1 is larger than the outer diameter of the drive gear 5, so as not to hinder the rotation of the drive gear 5 housed within the gear chamber 7b1. The shape of the gear chamber 7b1 can be arbitrarily changed in design as long as it allows the rotation of the drive gear 5 housed within the gear chamber 7b1, but by making the shape of the gear chamber 7b1 circular, the outer shape of the gear housing 7b can also be made concentric and circular, making the gear housing 7b smaller.

[0023] Furthermore, as shown in Figures 2 and 4, the pump section 7a includes a hole 7a2 that opens eccentrically from the center of the pump chamber 7a1 into which the shaft 4b of the inner rotor 4 (described later) is inserted, and an annular bracket 7a3 having bolt insertion holes on its outer circumference. The gear housing section 7b includes a hole 7b2 that opens from the center of the gear chamber 7b1 into which the shaft 5b of the drive gear 5 (described later) is inserted, and an annular bracket 7b3 having bolt insertion holes at two locations on its outer circumference.

[0024] The mounting portion 7c is annular in shape and extends to the side of the pump portion 7a. It includes four valve holes 7c1, 7c2, 7c3, and 7c4, five bolt insertion holes 7c5, an annular recess 7c6 located on the upper side of the inner circumference, an annular seal groove 7c7 located on the inner circumference below the annular recess 7c6, and four fan-shaped recesses 7c8 located at positions that avoid the valve holes 7c1, 7c2, 7c3, and 7c4 and the bolt insertion holes 7c5 in the circumferential direction, and which lead to the annular recess 7c6. The mounting portion 7c also includes a circular protrusion 7c9 that projects downward, as shown in Figure 4.

[0025] As shown in Figure 5, valve hole 7c1 opens from the upper end of the mounting portion 7c and leads to the annular recess 7c6. As shown in Figure 6, valve hole 7c2 opens from the lower end of the mounting portion 7c and leads to the pump chamber 7a1. As shown in Figure 7, valve hole 7c3 penetrates the mounting portion 7c in the axial vertical direction and branches off midway to lead to the annular recess 7c6. Furthermore, as shown in Figure 8, valve hole 7c4 penetrates the mounting portion 7c in the axial vertical direction.

[0026] Furthermore, a seal ring 10 is installed in the seal groove 7c7 on the inner circumference of the mounting portion 7c, which is in close contact with the outer circumference of the cylinder 30 in the shock absorber body D described later, thereby sealing the space between the case 2 and the cylinder 30.

[0027] Furthermore, an annular seal groove 7d is provided along the upper edge of the pump section 7a, gear housing section 7b, and mounting section 7c of the case body 7, surrounding the pump chamber 7a1, gear chamber 7b1, valve holes 7c1, 7c2, 7c3, 7c4, and recess 7c8.

[0028] As shown in Figure 3, the lid 8 has an outer shape that corresponds to the case body 7, and when placed on top of the case body 7, it closes the pump chamber 7a1 and gear chamber 7b1 of the case body 7. Specifically, in this embodiment, the lid 8 comprises a central portion 8a that is placed on top of the pump portion 7a of the case body 7 to cover the pump chamber 7a1, a tip portion 8b that is connected to the side of the central portion 8a and is placed on top of the gear housing portion 7b to cover the opening of the gear chamber 7b1 and to which the motor 6 is attached, and an annular base portion 8c that is connected to the side of the central portion 8a and is placed on top of the mounting portion 7c, which will be described later.

[0029] As shown in Figure 3, the central section 8a, when superimposed on the pump section 7a of the case body 7, has a hole 8a2 that opens eccentrically from the center of the pump chamber 7a1, with the shaft 4b of the inner rotor 4 (described later) being inserted into a hole 8a2 positioned vertically opposite to the hole 7a2, and an annular bracket 8a3 having bolt insertion holes positioned opposite to the outer bracket 7a3. As shown in Figure 3, the tip section 8b, when superimposed on the gear housing section 7b of the case body 7, has a hole 8b2 that opens vertically opposite to the hole 7b2, with the shaft 5b of the drive gear 5 being inserted into a hole 8b2, and an annular bracket 8b3 having bolt insertion holes positioned opposite to the two outer brackets 7b3. In addition, three mounting pieces 8e are provided on the outer circumference of the central section 8a and the tip section 8b for attaching the motor 6. As shown in Figure 4, the mounting pieces 8e are provided with screw holes 8e1 that open from above the lid 8, and the motor 6 is fixed to the case 2 by screw fastening.

[0030] Furthermore, the base portion 8c is annular and includes a partition wall portion 8c1 whose inner diameter is larger than the inner diameter of the annular recess 7c6 of the case body 7, four fan-shaped recesses 8c2 provided in the partition wall portion 8c1 and facing the recess 7c8 in the vertical direction when superimposed on the mounting portion 7c of the case body 7, an annular socket 8c3 that protrudes upward from the upper end of the partition wall portion 8c1 in Figure 4 and surrounds the recesses 8c2, a passage hole 8c4 provided in the partition wall portion 8c1 and facing the valve hole 7c4 in the vertical direction when superimposed on the mounting portion 7c of the case body 7, and five bolt insertion holes 8c5 that face the bolt insertion hole 7c5 in the vertical direction.

[0031] Furthermore, the lid 8 has a seal groove 8f that faces the seal groove 7d when placed on top of the case body 7. Then, the seal ring 11 is inserted into the seal grooves 7d and 8f, the lid 8 is placed on top of the case body 7, bolts (not shown) are inserted into the bolt insertion holes 7c5 and 8c5 and brackets 7a3, 7b3, 8a3, and 8b3, and nuts are screwed onto these bolts and tightened, thereby joining the case body 7 and the lid 8 in a sealed state by the seal ring 11.

[0032] Furthermore, the lid 8 has a groove 8d formed at the end facing the case body 7, extending from the central part 8a to the base end 8c, and leading to the pump chamber 7a1. When the lid 8 is placed on the case body 7, the groove 8d has an arc-shaped recess 8d1 facing the valve holes 7c1 and 7c3, and a connecting recess 8d2 extending from the arc-shaped recess 8d1 toward the central part 8a and leading to the pump chamber 7a1.

[0033] As shown in Figure 1, Case 2 is fitted to the outer circumference of the middle portion of the cylinder 30 of the shock absorber body D, which will be described later, by fitting the inner circumference of Case 7 to the outer circumference of Case 2, and is interposed between the upper cylinder 33a and the lower cylinder 33b that form the outer cylinder 33 covering the cylinder 30. In addition, the mounting portion 7c of Case 2 of Case 7 divides the annular gap formed between the cylinder 30 and the outer cylinder 33 into the upper tank T and the reservoir chamber R in Figure 1.

[0034] When case 2 is fitted onto the cylinder 30 of the shock absorber body D in this manner, and case 2 is interposed between the upper cylinder 33a and the lower cylinder 33b of the outer cylinder 33, as shown in Figure 2, when viewed from the axial direction, a part of the outer rotor 3 is positioned between the cylinder 30 and the outer cylinder 33.

[0035] Furthermore, the base end 8c of the lid 8 in case 2 in A baffle plate 20 is attached to the inner circumference of the socket 8c3. The baffle plate 20 comprises a main body portion 20a which is annular in shape and has an inner diameter set to be the same as the inner diameter of the mounting portion 7c of the case body 7, and has a plurality of notches 20a1 on its inner circumference, and an annular fitting portion 20b which rises upward in Figure 4 from the outer circumference of the main body portion 20a and fits onto the inner circumference of the socket 8c3.

[0036] As described above, the baffle plate 20 faces the tank T of the shock absorber body D, and allows communication between the tank T and the annular recess 7c6 of the case body 7 via the notch 20a1. The baffle plate 20 prevents air bubbles from entering the internal gear pump 1 if they form on the liquid surface in the tank T due to the operation of the internal gear pump 1 or vibrations input to the shock absorber body D. Note that the baffle plate 20 may be omitted if it is not needed.

[0037] The outer rotor 3 is annular and has internal teeth 3a on its inner circumference and external teeth 3b on its outer circumference. The shape of the internal teeth 3a is a trochoidal curve tooth profile, and the shape of the external teeth 3b is an involute curve tooth profile. However, the shapes of the internal teeth 3a and external teeth 3b are not limited to those described above. The outer rotor 3 is housed in the pump chamber 7a1 of the case body 7, and the outer surface of the external teeth 3b is In the case body 7 The outer rotor 3 is in sliding contact with the side wall of the recess that forms the pump chamber 7a1. Therefore, the outer rotor 3 can rotate circumferentially without any play relative to the pump section 7a in the case body 7.

[0038] The inner rotor 4 comprises a disc-shaped body 4a with external teeth 4a1 on its outer circumference that mesh with the internal teeth 3a of the outer rotor 3, and a shaft 4b that passes through the center of the body 4a. The shape of the external teeth 4a1 is a trochoidal curve tooth profile that meshes with the internal teeth 3a of the outer rotor 3. The shaft 4b extends from both the upper and lower sides of the body 4a, with one end rotatably inserted into a hole 7a2 provided in the pump section 7a of the case body 7, and the other end rotatably inserted into a hole 8a2 provided in the central part 8a of the lid 8, and housed in the pump chamber 7a1. The shaft 4b slides against the inner circumference of the holes 7a2 and 8a2, and the inner rotor 4 is supported by the case 2 and can rotate circumferentially within the pump chamber 7a1. Furthermore, since holes 7a2 and 8a2 are located eccentrically from the rotation center of the outer rotor 3, the inner rotor 4 is positioned eccentrically with respect to the outer rotor 3, and its external teeth 4a1 mesh with the internal teeth 3a. When the outer rotor 3 rotates, the inner rotor 4, which meshes with the outer rotor 3, also rotates. Because the inner rotor 4 is eccentric with respect to the outer rotor 3, as the outer rotor 3 and inner rotor 4 rotate, the gap between the internal teeth 3a of the outer rotor 3 and the external teeth 4a1 of the inner rotor 4 The sky The volume of the gap changes.

[0039] The drive gear 5 comprises a disc-shaped body 5a positioned on the outer circumference of the outer rotor 3 and equipped with external teeth 5a1 on its outer circumference that mesh with the external teeth 3b of the outer rotor 3, and a shaft 5b passing through the center of the body 5a. The shape of the external teeth 5a1 is an involute curve tooth profile that meshes with the external teeth 3b of the outer rotor 3. Note that the tooth profiles of the external teeth 5a1 of the drive gear 5 and the external teeth 3b of the outer rotor 3 are involute curve tooth profiles, but are not limited to this. The number of teeth of the external teeth 5a1 of the drive gear 5 is less than the number of teeth of the external teeth 3b of the outer rotor 3, and the drive gear 5 and the outer rotor 3 constitute a reduction gear. Furthermore, the reduction ratio between the drive gear 5 and the outer rotor 3 is set to be greater than the reduction ratio between the inner rotor 3 and the outer rotor 4.

[0040] The shaft 5b extends from both the upper and lower sides of the main body 5a, with one end rotatably inserted into a hole 7b2 provided in the gear housing portion 7b of the case body 7, and the other end rotatably inserted into a hole 8b2 of the lid 8. The shaft 5b slides against the inner circumference of holes 7b2 and 8b2, and the drive gear 5 is supported by the case 2 and can rotate in the circumferential direction.

[0041] The motor 6 is bolted to the mounting piece 8e of the cover 8 and fixed to the case 2. The output shaft 6a of the motor 6 is connected to the shaft 5b of the drive gear 5. Therefore, when the motor 6 is driven, the drive gear 5 is rotated, which in turn rotates the outer rotor 3 with which the drive gear 5 meshes, and further in turn rotates the inner rotor 4 with which the outer rotor 3 meshes.

[0042] When the motor 6 is driven to rotate the outer rotor 3 and inner rotor 4 clockwise in Figure 2, with respect to line L connecting the rotation center of the outer rotor 3 and the rotation center of the inner rotor 4, the gap between the outer rotor 3 and the inner rotor 4 expands to the right of line L as the rotation of the outer rotor 3 and the inner rotor 4 progresses, and to the left of line L as the rotation of the outer rotor 3 and the inner rotor 4 progresses, the gap between the outer rotor 3 and the inner rotor 4 decreases. On the other hand, when the motor 6 is driven to rotate the outer rotor 3 and inner rotor 4 counterclockwise in Figure 2, with respect to line L connecting the rotation center of the outer rotor 3 and the rotation center of the inner rotor 4, the gap between the outer rotor 3 and the inner rotor 4 decreases to the right of line L as the rotation of the outer rotor 3 and the inner rotor 4 progresses, and to the left of line L as the rotation of the outer rotor 3 and the inner rotor 4 progresses, the gap between the outer rotor 3 and the inner rotor 4 expands. The gap to the right of line L communicates with valve holes 7c1 and 7c3 via the arc-shaped recess 8d1 of the cover 8, and the gap to the left of line L communicates with valve hole 7c2.

[0043] As shown in Figure 5, the valve hole 7c1 in case 2 is connected to the pump chamber 7a1 via an arc-shaped recess 8d1 formed in the lid 8, and is also connected to an annular recess 7c6. Since the annular recess 7c6 is connected to the tank T in the buffer body D, the valve hole 7c1 connects the pump chamber 7a1 and the tank T, forming the suction passage P1 in the internal gear pump 1. The valve hole 7c2 in case 2 connects the pump chamber 7a1 and the reservoir chamber R in the buffer body D, forming the discharge passage P2 in the internal gear pump 1.

[0044] As shown in Figure 5, the inner diameter of the valve hole 7c1 is enlarged at the top, and a check valve 21 with a spherical valve body is housed within the enlarged portion of the valve hole 7c1 so as to be movable in the vertical direction. When the outer rotor 3 and inner rotor 4 are rotated clockwise in Figure 2, the gap between the outer rotor 3 and inner rotor 4 on the right side of the line L communicating with the arc-shaped recess 8d1 expands, causing the pressure in the pump chamber 7a1 to drop below the pressure in the tank T. As a result, the check valve 21 housed in the valve hole 7c1 moves upward within the valve hole 7c1, opening the suction passage P1 and connecting the tank T to the pump chamber 7a1. On the other hand, when the outer rotor 3 and inner rotor 4 are rotated counterclockwise in Figure 2, the check valve 21 housed in the valve hole 7c1 is positioned at the lowest point within the enlarged portion of the valve hole 7c1, blocking the suction passage P1 and severing communication between the pump chamber 7a1 and the tank T via the valve hole 7c1.

[0045] Furthermore, as shown in Figure 6, the inner diameter of the valve hole 7c2 is enlarged at the bottom, and a check valve 22 with a spherical valve body is housed within the enlarged portion of the valve hole 7c2 so as to be movable in the vertical direction. When the outer rotor 3 and inner rotor 4 are rotated clockwise in Figure 2, the gap between the outer rotor 3 and inner rotor 4 on the left side of the line L communicating within the valve hole 7c2 is reduced, causing the pressure in the pump chamber 7a1 to become higher than the pressure in the reservoir chamber R, and the check valve 22 housed in the valve hole 7c2 moves downward within the valve hole 7c2. Discharge passage P2 Open it Reservoir Room RThis is connected to the pump chamber 7a1. Although not shown in the diagram, the case body 7 is provided with a retainer to prevent the valve body of the check valve 22 from falling out of the valve hole 7c2.

[0046] On the other hand, the check valve 22 housed in the valve bore 7c2 is pressed by the pressure in the reservoir chamber R when the outer rotor 3 and inner rotor 4 are rotated counterclockwise in Figure 2, or when the motor 6 is stopped. te ben It is positioned at the uppermost part within the enlarged diameter portion of hole 7c2, blocking the discharge passage P2 and severing communication between the pump chamber 7a1 and the reservoir chamber R via valve hole 7c2.

[0047] Therefore, when the motor 6 is driven to rotate the outer rotor 3 and inner rotor 4 clockwise in Figure 2, the check valves 21 and 22 open, and the internal gear pump 1 draws liquid from the tank T and discharges it into the reservoir chamber R.

[0048] As shown in Figure 7, the valve hole 7c3 in case 2 is connected to the pump chamber 7a1 via an arc-shaped recess 8d1 formed in the lid 8 and also to an annular recess 7c6. The valve hole 7c3 comprises a vertical hole 7c31 that penetrates the mounting portion 7c vertically and has an enlarged inner diameter on the lower side, and an oblique hole 7c32 that connects the middle of the vertical hole 7c31 to the annular recess 7c6. The valve hole 7c3 forms a discharge passage P3 connecting the reservoir chamber R and the tank T with the lower side of the vertical hole 7c31 and the oblique hole 7c32.

[0049] As shown in Figure 7, an operable check valve 23 is housed within the valve hole 7c3, comprising a spool 23a that slides against the inner circumference of the vertical hole 7c31 and is movable vertically within the vertical hole 7c31, and a spherical valve body 23b that is housed below the connection point of the oblique hole 7c32 of the vertical hole 7c31 and is movable vertically inside the enlarged portion, and abuts against the lower end of the spool 23a. When the valve body 23b seats on the annular stepped portion 7c33 formed by the enlarged portion of the vertical hole 7c31, it closes the vertical hole 7c31, and when it moves away from the stepped portion 7c33, it opens the vertical hole 7c31.

[0050] Therefore, the Operate Check Valve 23 enters a closed state when the valve body 23b is positioned at the uppermost position inside the enlarged portion of the vertical hole 7c31 and seated on the stepped portion 7c33. Conversely, the Operate Check Valve 23 enters an open state when the valve body 23b is positioned below the uppermost position inside the enlarged portion of the vertical hole 7c31, separating from the stepped portion 7c33 of the vertical hole 7c31, thereby opening the vertical hole 7c31 and connecting the reservoir chamber R and the tank T through the vertical hole 7c31 and the oblique hole 7c32. Although not shown in the figures, the case body 7 is provided with a retainer for the valve body 23b to prevent it from falling out of the vertical hole 7c31.

[0051] When the outer rotor 3 and inner rotor 4 are rotated clockwise in Figure 2, the check valve 21 opens, and the arc-shaped recess 8d1, which leads to valve hole 7c3 through valve hole 7c1, communicates with the tank T, so that the pressure in the arc-shaped recess 8d1 becomes equal to the pressure in the tank T. Then, the spool 23a, together with the valve body 23b, is pushed upward by the pressure in the reservoir chamber R, and the valve body 23b is positioned at the uppermost position inside the enlarged portion of the vertical hole 7c31, blocking the discharge passage P3. Also, when the outer rotor 3 and inner rotor 4 are rotated clockwise in Figure 2 and then the motor 6 is stopped, the check valve 21 closes, but the pressure in the arc-shaped recess 8d1 remains low, so the operated check valve 23 maintains the state of blocking the discharge passage P3.

[0052] On the other hand, when the outer rotor 3 and inner rotor 4 are rotated counterclockwise in Figure 2, the gap between the outer rotor 3 and inner rotor 4 to the right of line L shrinks, supplying liquid to the arc-shaped recess 8d1 that leads to the gap, and increasing the pressure in the arc-shaped recess 8d1. The arc-shaped recess 8d1 is in communication with valve holes 7c1 and 7c3. When the pressure in the arc-shaped recess 8d1 increases, it closes the check valve 21 in valve hole 7c1. At the same time, the spool 23a of the operate check valve 23 is pushed down in the vertical hole 7c31, and the valve body 23b is pushed by the spool 23a, moving below the uppermost point inside the enlarged portion of the vertical hole 7c31, opening the discharge passage P3 and connecting the reservoir chamber R and the tank T. To close the operate check valve 23, the outer rotor 3 and inner rotor 4 are driven clockwise in Figure 2 to stop the motor 6.

[0053] Next, as shown in Figure 8, the valve hole 7c4 and the passage hole 8c4 opposite the valve hole 7c4 form a relief passage P4 that connects the reservoir chamber R and the tank T. A relief valve 24 is housed inside the valve hole 7c4, comprising a valve body 24a and a spring 24b that biases the valve body 24a. When the pressure in the reservoir chamber R reaches the opening pressure, the relief valve 24 receives the pressure from the reservoir chamber R, causing the valve body 24a to compress the spring 24b, move upward within the valve hole 7c4, and open the relief passage P4, connecting the reservoir chamber R and the tank T. When the pressure in the reservoir chamber R does not reach the opening pressure, the relief valve 24 is closed by the spring 24b, which positions the valve body 24a at its lowest position within the valve hole 7c4, blocking the relief passage P4. In this way, the relief valve 24 prevents the pressure in the reservoir chamber R from becoming excessive by releasing the liquid in the reservoir chamber R to the tank T when the pressure in the reservoir chamber R exceeds the opening pressure.

[0054] 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.

[0055] 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.

[0056] Furthermore, the case 2 of the internal gear pump 1 is fitted to the outer circumference of the middle portion of the cylinder 30. Specifically, the outer circumference of the cylinder 30 is fitted to the inner circumference of the mounting portion 7c of the case body 7 in Figure 1, and the cylinder 30 is inserted into the base end portion 8c of the cover 8. As mentioned above, the space between the case 2 and the cylinder 30 is sealed by a seal ring 10 that is fitted in a seal groove 7c7 provided on the inner circumference of the mounting portion 7c of the case body 7 and is in close contact with the outer circumference of the cylinder 30.

[0057] 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 a socket 8c3 of the base end 8c of the lid 8 of the case 2 of the internal gear pump 1, which fits onto the outer circumference of the cylinder 30, is fitted inside the lower end of the upper cylinder 33a. The lower cylinder 33b is closed at its lower end by a bottom cap 37 equipped with a bracket 37a that allows mounting to a vehicle (not shown), and its upper end is fitted onto the outer circumference of a protrusion 7c9 of the mounting portion 7c of the case body 7. Furthermore, the case 2 of the internal gear pump 1 and the upper cylinder 33a, and the case 2 and the lower cylinder 33b are joined by welding or the like.

[0058] 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.

[0059] 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.

[0060] 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 33bThe 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] When the motor 6 drives the internal gear pump 1, causing both the outer rotor 3 and the inner rotor 4 to rotate clockwise in Figure 2, the check valves 21 and 22 open, drawing liquid from the tank T through the suction passage P1 and discharging it into the reservoir chamber R via 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, supplying liquid from the reservoir chamber R to the compression chamber R2. Furthermore, the inflow of liquid into the compression chamber R2 pushes the piston 31 upward, causing the extension damping valve 31c to open from the extension chamber R1, whose volume has decreased, and liquid moves from the extension chamber R1 to the compression chamber R2 via 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 valves 21 and 22 to close, maintaining the fluid levels in the reservoir chamber R and cylinder 30, thus maintaining the vehicle height.

[0069] 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.

[0070] When the motor 6 drives both the outer rotor 3 and the inner rotor 4 of the internal gear pump 1 in a counterclockwise direction as shown in Figure 2, the check valves 21 and 22 are closed and the operate check valve 23 is opened. As a result, 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.

[0071] When 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 motor 6 is driven to drive both the outer rotor 3 and inner rotor 4 clockwise in Figure 2 and then stopped, the operate check valve 23 closes, cutting off communication between reservoir chamber R and tank T through the discharge passage P3, and check valves 21 and 22 also close, thus maintaining the amount of liquid in reservoir chamber R and cylinder 30 and maintaining the vehicle height.

[0072] 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.

[0073] As described above, the internal gear pump 1 of this embodiment comprises a case 2, an annular outer rotor 3 having internal teeth 3a on its inner circumference and external teeth 3b on its outer circumference and rotatably housed in the case 2 in the circumferential direction, an inner rotor 4 housed in the case 2 and inserted into the inner circumference side of the outer rotor 3 and meshing with the outer rotor 3, a drive gear 5 meshing with the external teeth 3b of the outer rotor 3, and a motor 6 for driving the drive gear, characterized in that the number of teeth of the drive gear 5 is less than the number of teeth of the external teeth 3b of the outer rotor 3.

[0074] Since the number of teeth on the drive gear 5 is less than the number of teeth on the outer rotor 3b, the drive gear 5 and the outer rotor 3 form a reduction gear, and the torque required for the motor 6 that drives the drive gear 5 to drive the outer rotor 3 and the inner rotor 4 can be reduced. With the internal gear pump 1 configured in this way, the torque required to drive the drive gear 5 to drive the outer rotor 3 and the inner rotor 4 is small, so the motor 6 can be made smaller. In addition, in the internal gear pump 1 of this embodiment, since the motor 6 can be made smaller, even when the internal gear pump 1 is integrated with equipment that receives liquid from the internal gear pump 1 to form a hydraulic device, the motor 6 does not get in the way, improving the ease of mounting on equipment and also enabling the miniaturization of the hydraulic device.

[0075] Furthermore, since the inner rotor 4, outer rotor 3, and drive gear 5 are housed within the case 2, and the pump and reduction gear are integrated into a single structure, the internal gear pump 1 can be made compact.

[0076] Furthermore, the system includes an internal gear pump 1 and a buffer body (device) D integrated with the case 2 to receive the supply and discharge of liquid from the internal gear pump 1, with the buffer body (device) D being cylindrical. Even though the buffer body (device) D that receives the liquid supply from the internal gear pump 1 is cylindrical, the motor 6 directly drives the drive gear 5 located on the outer circumference of the outer rotor 3. Therefore, even if the pump section of the internal gear pump 1, consisting of the outer rotor 3 and inner rotor 4, is placed very close to the buffer body (device) D, the motor 6, which is coaxial with the drive gear 5, can be easily positioned in a location that does not interfere with the buffer body (device) D. In this embodiment of the internal gear pump 1, the portion of the case 2 that fits into the cylinder 30 (the mounting portion 7c of the case body and the base end portion 8c of the cover 8), the pump portion (the outer rotor 3, the inner rotor 4, and the portion of the case 2 that houses these), and the drive portion consisting of the drive gear 5 and the motor 6 arranged coaxially with the drive gear 5 are arranged in a substantially straight line. However, the drive portion can change its installation position along the outer circumference of the outer rotor 3 with the rotation center of the outer rotor 3 as the center in Figure 2, so the arrangement of the drive portion relative to the pump portion can be arbitrarily changed according to the specifications of the shock absorber body (equipment) D and the mounting space of the vehicle on which the shock absorber body (equipment) D is installed.

[0077] 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 with the buffer body (device) D. However, if integration with the device is not necessary, the mounting portion 7c of the case body 7 and the base end portion 8c of the lid 8 in the case 2 may be omitted. Alternatively, instead of the operate check valve 23, a check valve that allows only the flow of liquid from the buffer body (device) D to the pump chamber 7a1 and a check valve that allows only the flow of liquid from the pump chamber 7a1 to the tank T may be provided, and the internal gear pump 1 may be configured such that when discharging liquid from the reservoir chamber R to the tank T, the motor 6 drives the outer rotor 3 and the inner rotor 4 counterclockwise to draw liquid from the reservoir chamber R and discharge the liquid to the tank T.

[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 in which the case 2 is connected to the outer cylinder 33 and supplies and discharges liquid into the cylinder 30, wherein the annular gap between the cylinder 30 and the outer cylinder 33 is divided by the case 2 into a tank T for storing liquid and a reservoir chamber R which 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, and the internal gear pump 1 supplies and discharges liquid into the cylinder 30 via the reservoir chamber R.

[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] Furthermore, in the shock absorber SA with ride height adjustment function of this embodiment, when viewed from the axial direction, a portion of the outer rotor 3 is positioned inward from the outer circumference of the outer cylinder 33. With the shock absorber SA with ride height adjustment function configured in this way, since a portion of the outer rotor 3 is positioned inward from the outer circumference of the outer cylinder 33, the pump portion of the internal gear pump 1 can be positioned very close to the shock absorber body D, and the overall outer diameter including the internal gear pump 1 can be reduced. Also, since a portion of the outer rotor 3 is positioned inward from the outer circumference of the outer cylinder 33, the pump chamber 7a1 can be installed very close to the reservoir chamber R and the tank T when viewed from the axial direction, so the suction passage P1 and discharge passage P2 that supply liquid from the tank T to the reservoir chamber R can be made extremely short and can be made with holes of an even simpler shape. Therefore, the shock absorber SA with ride height adjustment function configured in this way can be made even smaller.

[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 gears, 3b...External gears, 4...Inner rotor, 5...Drive gear, 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

[Claim 1] 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, The device comprises a case, an annular outer rotor having internal teeth on its inner circumference and external teeth on its outer circumference, and rotatably housed within the case, an inner rotor housed within the case and inserted into the inner circumference of the outer rotor, and consisting of an external gear that meshes with the outer rotor, a drive gear that meshes with the external teeth of the outer rotor, and a motor that drives the drive gear, the case being connected to the outer cylinder, and an internal gear pump that supplies and discharges liquid into the cylinder, The number of teeth of the drive gear is less than the number of teeth of the outer rotor's external teeth. When the outer cylinder is viewed from the axial direction, a portion of the outer rotor is positioned inward from the outer circumference of the outer cylinder. A shock absorber with ride height adjustment function, characterized by the following features.

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