Rotation support structure for electric cylinder

Abstract

To obtain a rotation support structure of an electric cylinder which does not cause interference between members while enhancing a degree of freedom of a component constitution, and is compact in a size.SOLUTION: A rotation support structure of an electric cylinder D comprises a cylindrical housing H, a motor M having an output shaft A1 and a reduction mechanism K connected to the output shaft A1. The reduction mechanism K comprises a gear unit U having a pivot part 2 having a first gear G1 which is driven-rotated to the output shaft A1 at one side, and attached with an outer member 4 and balls 1 which are co-rotated together with the first gear G1 at the other side, and oppose an internal peripheral face of the housing H, and an annular second gear G2 fixed to the internal peripheral face of the housing H, and screwed with the first gear G1. The second gear G2 and the pivot part 2 are arranged in an extension direction of an axial core X while separating from each other in a view in a direction orthogonal to the axial core X of the output shaft A1, and the outer member 4 and the first gear G1 are arranged in a state that they are separated from each other in a view in a direction along the axial core X.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the rotational support of an electric cylinder, for example, in which a reduction mechanism is connected to the output shaft of a motor. It relates to a structure.

Background Art

[0002] Conventionally, as such a rotational support structure, there is, for example, one shown in Patent Document 1 (see

[0024] to

[0029] and FIGS. 1 and 2). 4] to

[0029] and FIGS. 1 and 2).

[0003] This rotational support structure is a hydraulic module of an electro-hydraulic servo brake, and hydraulic fluid is supplied to the brake by a piston driven by a motor. It is.

[0004] In this rotational support structure, a pinion 511 serving as a sun gear is attached to the shaft 52 of the motor 5, and a plurality of planetary gears 512 are engaged with this pinion 511. The plurality of planetary gears 512 are supported by a sleeve 62 that constitutes a piston, and this sleeve 62 serves as a so-called carrier. A ring gear (not shown) is disposed on the outer peripheral side of the planetary gear 512, and these planetary gear mechanisms are covered by a bottomed cylindrical hood 513. The sleeve 62 that functions as a carrier is held by the housing 7 via a bearing 72. The sleeve 62 reciprocates the piston 3 along the inner wall of the cylinder 2 via a ball 63 and a threaded core 61. A ring 35 that protrudes radially outward is attached to the end of the piston 3, and the piston 3 can reciprocate in a non-rotating manner by moving along a plurality of cuts 351 provided on this ring 35 along needles 21 attached to the housing 7. The sleeve 62 that functions as a carrier is held by the housing 7 via a bearing 72. 2 serves as a so-called carrier. A ring gear (not shown) is disposed on the outer peripheral side of the planetary gear 512, and these planetary gear mechanisms are covered by a bottomed cylindrical hood 513. The sleeve 62 that functions as a carrier is held by the housing 7 via a bearing 72. The sleeve 62 that functions as a carrier is held by the housing 7 via a bearing 72. The sleeve 62 that functions as a carrier is held by the housing 7 via a bearing 72.

[0005] The sleeve 62 reciprocates the piston 3 along the inner wall of the cylinder 2 via a ball 63 and a threaded core 61. A ring 35 that protrudes radially outward is attached to the end of the piston 3, and the piston 3 can reciprocate in a non-rotating manner by moving along a plurality of cuts 351 provided on this ring 35 along needles 21 attached to the housing 7. The sleeve 62 reciprocates the piston 3 along the inner wall of the cylinder 2 via a ball 63 and a threaded core 61. A ring 35 that protrudes radially outward is attached to the end of the piston 3, and the piston 3 can reciprocate in a non-rotating manner by moving along a plurality of cuts 351 provided on this ring 35 along needles 21 attached to the housing 7. A ring 35 that protrudes radially outward is attached to the end of the piston 3, and the piston 3 can reciprocate in a non-rotating manner by moving along a plurality of cuts 351 provided on this ring 35 along needles 21 attached to the housing 7. The piston 3 can reciprocate in a non-rotating manner by moving along a plurality of cuts 351 provided on this ring 35 along needles 21 attached to the housing 7. It can.

[0006] With this configuration, the rotating support structure does not increase the required space, For the guidance of piston 3 and to prevent the rotation of piston 3, a simple and reliable construction method It is said to possess the necessary characteristics. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2020-536784 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In the conventional rotational support structure of the electric cylinder described above, the pinion 511 which serves as the sun gear and , a sleeve 62 that functions as both a carrier and a piston supporting the planetary gear 512 and The planetary gear mechanism is formed by the ring gear fixed to the outer circumference of the planetary gear 512. Furthermore, the sleeve 62, together with the thread core 61 and the ball 63, constitutes a screw mechanism. These planetary gear mechanisms and screw mechanisms are integrated into a single unit.

[0009] However, among these components, the sleeve 62, which is the carrier, has a hollow structure. This creates constraints on the position where the rotation axis of the planetary gear 512 is attached. Therefore, the sleeve The size of the component increases, as it becomes necessary to give component 62 a specific thickness. Also, they are arranged in close proximity to each other. The bearing 72, which is integrally formed on the outer circumference of the sleeve 62, and the ring gear come into contact. It becomes easier. To avoid this, the meshing diameter of the planetary gear 512 and the ring gear and It is necessary to bring the PCD of the ring 72 closer, and the shape of the component is constrained, therefore The size of the member becomes large.

[0010] Thus, in the above-described conventional rotation support structure, there are various problems to be solved , and there has been a demand for a rotation support structure of a compact electric cylinder without interference between members while increasing the degree of freedom of component configuration. [Means for Solving the Problems]

[0011] (Characteristic Configuration) The characteristic configuration of the rotation support structure of the electric cylinder according to the present invention is a cylindrical housing, a motor attached to the housing and having an output shaft, a speed reduction mechanism built in the housing and connected to the output shaft, and the speed reduction mechanism has a first gear that rotates driven by the output shaft on one side, and on the other side, a gear unit that rotates together with the first gear and includes an outer member facing the inner surface of the housing and a shaft support portion to which balls are attached, and an annular second gear fixed to the inner surface of the housing and meshing with the first gear. In a view in a direction orthogonal to the axis of the output shaft, the second gear and the shaft support portion are arranged in a state of being separated in the extending direction of the axis, and in a view in a direction along the axis, the outer member and the first gear are arranged in a state of being separated in the radial direction. 、 The outer member is movable in a direction along the axis and can come into contact with the second gear. Compared to the side surface of the outer member facing the second gear, the side surface of the pivot support facing the second gear is spaced further apart from the second gear. is in this point.

[0012] (Effect) In the rotation support structure of the electric cylinder of the present invention, a speed reduction mechanism is provided, and a plurality of members constituting the speed reduction mechanism rotate relative to each other inside the housing. Therefore, it is necessary to effectively prevent mutual interference between the members.

[0013] Therefore, in this configuration, the arrangement state between the rotating member and the fixed member disposed in its vicinity is defined. Specifically, the installation state of the first gear that rotates integrally and the shaft support is defined. .

[0014] For the first gear, the installation state with the outer member in the adjacent region along the axis of the output shaft is defined. The side surface of the pivot support facing the second gear is spaced further away from the second gear than the side surface of the outer member facing the second gear. Therefore, when the outer member moves in the direction along the axis and comes into contact with the second gear, interference between the second gear and the pivot support can be prevented. Also, for the shaft support, it is defined that the radial dimension is different from that of the second gear. By these, even if the first gear and the shaft support move along the axis due to assembly errors, position shifts during motor driving, etc., mutual interference between the members can be surely prevented.

[0015] Furthermore, in this configuration, it is not necessary to prevent interference between the members by matching the meshing diameter between the first gear and the second gear and the position (PCD: Pitch Circle Diameter) of the balls of the bearing. . .

[0016] (Characteristic configuration) In the rotational support structure of the electric cylinder according to the present invention, for the shaft support and the outer member facing each other with the ball interposed therebetween, the length of the shaft support along the extending direction of the axis is shorter than the length of the outer member. and can be configured. May it happen .

[0017] (Effect) In the rotational support structure for an electric cylinder according to the present invention, The length of the shaft support along the axis of the output shaft is shorter than the length of the outer member in the same direction. That would be convenient. The positional relationship between the side surface of the shaft support and the side surface of the outer member can be surely and easily defined by interposing a ball between them. Therefore, interference between the shaft support, which is a rotating member, and the second gear, which is a fixed member, can be surely prevented.

[0018] (Characteristic configuration) In the rotational support structure of the electric cylinder according to the present invention, the gear unit is a planetary gear mechanism A structure in which the first gear is a planetary gear, and the shaft support is a plurality of planetary gears A is a carrier that supports the output shaft, the output shaft is a sun gear, and the tip of the output shaft is tapered An inclined portion is provided, and the inclined portion is housed in the shaft support portion at a position facing the output shaft. It is convenient if a recess is provided for this purpose.

[0019] (effect) This configuration uses a rotational support structure for the electric cylinder when the gear unit is a planetary gear mechanism. It will be made more compact.

[0020] In other words, if the motor's output shaft is the sun gear and the first gear is a planetary gear, then the housing When the motor is installed after the gear unit, which includes the first gear, is attached to the rung. There is a first gear which is a planetary gear, which is the output shaft that protrudes from the motor. It is inserted into the designated position of A. In order to transmit the driving force rationally, the output shaft and the first gear and It is preferable that no backlash occurs between the output shaft and the first gear. The setting is designed to minimize the gap, and when the motor is installed, the tip of the output shaft does not interfere with the end of the first gear. It becomes easier to cross.

[0021] In this configuration, a tapered, inclined section is provided at the tip of the output shaft to facilitate motor installation. The design aims to improve the structure. The inclined section formed at the tip of the output shaft is connected to the first gear, which is a planetary gear. The meshing is reduced. Therefore, the inclined part penetrates the first gear and protrudes towards the pivot point. It is constructed in such a way. Therefore, a recess is formed in the part of the shaft support that faces the tip of the output shaft. By surrounding the inclined portion with this recess, the gear engagement length between the output shaft and the first gear is reduced. Instead, it absorbs the effect of the increased length of the output shaft due to the formation of the inclined section, and the rotation support structure is controlled It's attached to a compact. [Brief explanation of the drawing]

[0022] [Figure 1] Cross-sectional view showing the rotational support structure of the electric cylinder according to the first embodiment. [Figure 2] An explanatory diagram showing the state of each gap provided in the rotating support structure according to the first embodiment. [Figure 3] Cross-sectional view showing the rotational support structure of the electric cylinder according to the second embodiment. [Modes for carrying out the invention]

[0023] [First Embodiment] (overview) The rotational support structure of the electric cylinder D according to the present invention is such that the rotational driving force from the motor M is directed to the ball It is transmitted to other driven objects by a reduction mechanism K equipped with a shaft support 2 using 1, In this transmission, the reduction mechanism K is configured to be able to change its orientation relative to the housing H. ru.

[0024] (Deceleration mechanism) A specific configuration of the first embodiment of the rotational support structure is shown, for example, in Figures 1 and 2. Then, a reduction mechanism K is housed inside the cylindrical housing H, and on one side of the reduction mechanism K The piston P, which is the object to be driven, is located at the back of the housing H. In addition, the reduction mechanism K is also On one side, a motor M is connected so as to cover the reduction mechanism K.

[0025] The rotation of motor M is transmitted from the output shaft A1 of motor M to the reduction mechanism K, where the rotational speed is determined. After being significantly reduced, the force is transmitted to the piston P via the second output shaft A2 protruding from the rear side of the reduction mechanism K. It is communicated that the piston P consists of, for example, a base P2 on the motor M side and a head P1 on the tip side. The two parts are connected by screws or fittings. The outer diameter of the base P2 is slightly smaller than the outer diameter of the head P1. It has been formed into a crack.

[0026] The piston P slides along the inner surface of the housing H. The outer surface of the second output shaft A2 has a male thread. Part A23 is formed and screws into the female threaded part P2b formed on the inner surface of the base P2 of the piston P. Furthermore, the piston P moves thrust along the inner surface of the housing H, A guide groove P2a is formed on the outer surface of part P2, and from the wall surface of housing H, the guide groove P2a A protruding portion 3 is formed to engage with the housing H. This protruding portion 3 is, for example, formed on the outside of the wall surface of the housing H. It can be constructed by screwing in a screw member.

[0027] The reduction mechanism K is composed of, for example, a planetary gear mechanism. As shown in Figure 1, the sun gear A first gear G1, acting as a planetary gear, meshes with the output shaft A1 of the motor M, and multiple first gears A G1 is held by the pivot 2 which acts as a carrier. Bearings are attached to the outer circumference of the pivot 2. An annular groove 2a is formed along the circumferential direction to receive the ball 1 that makes up the ring. An outer member 4, which serves as the outer bearing support, is positioned on the outer circumference of the other half of the bearing.

[0028] The first gear G1 and the pivot 2, the ball 1, and the outer member 4 are pre-assembled as a gear unit U. It is assembled as one. In this way, the pivot 2 of the planetary gear mechanism and the outer bearing Since member 4 is formed integrally with the other, an independent ball bearing is mounted on the shaft support 2. Compared to that, the rotation support structure is simplified. Therefore, the number of components of the electric cylinder D is reduced. It can be made more compact, improving its compatibility with various devices.

[0029] The gear unit U is inserted into the housing H together with the second output shaft A2 and the piston P. A boss portion 2b is formed in the center of the pivot portion 2, protruding toward the piston P. Inside the boss portion 2b, two-tiered fitting holes 21 and serration holes 22 are formed. One end of the second output shaft A2 has a fitting projection A21 and a serrated projection A22. It is formed in a stepped shape, and the second output shaft A2 and the shaft support 2 are fitted and connected, so that they always rotate as a single unit. do.

[0030] The fitting connection between the second output shaft A2 and the shaft support 2 is achieved by simply fitting the end of the second output shaft A2 into the shaft support 2. Although it is simply a matter of inserting it, a pressing force is generated on the second output shaft A2 via the piston P toward the shaft support 2. Therefore, even when using a simple mating connection, the second output shaft A2 is properly connected to the shaft support 2. It can be fixed in place.

[0031] Furthermore, a rubber material is formed between the outer surface of the head portion P1 and the inner surface of the housing H. A seal ring 5 is installed. In Figure 1, a ring groove Ha is formed on the inner surface of the housing H. A seal ring 5 is fitted into it. Furthermore, by swapping the two, the outer surface of the head part P1 is... Alternatively, a configuration may be provided in a groove Ha into which the seal ring 5 is fitted.

[0032] When fitting the second output shaft A2 into the shaft support 2, as shown in Figure 1, an annular plate material is used. Spacer S is inserted between the shaft support 2 and the second output shaft A2. One side of spacer S is One side faces the stepped portion Hb of the housing H, and the other side faces the outer member 4. A spacer S is used. This ensures that the position of the gear unit U along the axis X relative to the housing H is accurate. This is how it will be. However, as will be described later, the spacer S is between the outer member 4 and the housing H. It is not completely fixed in place, but can be moved slightly.

[0033] Furthermore, the spacer S can be omitted. For example, the surface shape of the stepped portion Hb of the housing H. The shape is such that the outer member 4 can contact the stepped portion Hb in the correct position and without any looseness. When the gear unit U is in contact with the stepped portion Hb, along the direction of the axis X Spacer S may be omitted if the position of gear unit U can be precisely set.

[0034] (Mounting structure of the second gear) Following the insertion of the gear unit U into the housing H, the second gear G2 is attached. The internal teeth of gear G2 are engaged with multiple first gears G1 and inserted into housing H. The outer surface of gear G2 is cylindrical, and no play occurs during relative rotation with the first gear G1. The shape is set so that it contacts or comes very close to the inner surface of housing H. It is being done.

[0035] Near the end of the second gear G2 opposite to the piston P, there is a flange that protrudes radially. A section G2a is provided. Multiple fixing holes G2b are provided in the flange section G2a, The second gear G2 is fixed to the housing H using fixing members 6 such as belts.

[0036] Typically, gear components incorporated into motors M and other devices to transmit driving force are designed with durability and strength in mind. Therefore, materials different from those used for structural members are often selected. As a result, various gear components have gear functions. It is often composed of a single component that only has that. However, in this configuration, the annular second gear G2 A flange portion G2a is provided, which, in addition to the drive transmission function of the second gear G2, also serves as its own fixing function. This second gear G2 is then inserted into the gear unit U through an opening on one side of the housing H. Insert and position them consecutively.

[0037] This eliminates the need to prepare any special fixing parts other than the second gear G2, and the gear unit The installation of the U and the second gear G2 is made easier, and the configuration of the electric cylinder D is simplified. In particular, the flange portion G2a is located radially outward relative to the internal tooth portion, The reaction force of the rotational driving force acting from the first gear G1 to the second gear G2 causes the second gear G2 to rotate. When attempting this, the moment arm from the axis X to the flange portion G2a becomes longer. The mounting strength of the fixing member 6 that secures the flange portion G2a to the housing H is low. Done.

[0038] Furthermore, since the second gear G2 is fixed to the housing H outside the internal tooth portion, if, Even if the machining accuracy of fixed holes such as G2b is low and the second gear G2 rotates relative to the housing H The longer the distance from the axis X, the smaller the amount of play in the second gear G2.

[0039] (Motor mounting structure) Following the installation of the second gear G2, the motor M is attached to the housing H. An output shaft A1 is provided, and the output shaft A1 is connected to the first gear G1 of the already installed gear unit U. Attach while engaging. In order to efficiently transmit the driving force, the output shaft A1 and the first gear G It is preferable that no backlash occurs between the output shaft A1 and the first gear. The setting is designed to minimize play with A G1, and when motor M is installed, the tip of output shaft A1 The part is prone to interfering with the end of the first gear G1. To avoid this interference, the tip of the output shaft A1 A tapered inclined section A1a is provided. This inclined section A1a allows the output The tip of shaft A1 can easily engage with the central position of multiple first gears G1, making the installation of motor M easier. It becomes easier.

[0040] Furthermore, if this inclined section A1a were to mesh with the first gear G1, the meshing between the two would be small. Therefore, the inclined portion A1a passes through the first gear G1 and protrudes towards the pivot portion 2. It is configured as follows: To deal with this protrusion, the shaft support 2 is positioned opposite the tip of the output shaft A1. A recess 23 is formed in the area. This recess 23 surrounds the inclined portion A1a, and the output By forming the inclined portion A1a without reducing the tooth engagement length between shaft A1 and the first gear G1, This design absorbs the effects of the increased length of the output shaft A1, allowing the rotational support structure to remain compact.

[0041] (Changes in the attitude of the gear unit) In the rotational support structure of this embodiment, the gear unit U is positioned relative to the housing H. The posture can be changed. That is, as shown in the lower part of Figure 1, the axis Xu of the gear unit U A predetermined angular deviation is allowed between the motor M and the axis X. In this configuration, for example, When moving the ton P back and forth, if there are errors in the dimensions of the components or assembly of the reduction mechanism K and piston P Even if errors or other factors exist, the electric cylinder D can be driven smoothly.

[0042] During the reciprocating movement of piston P, a certain degree of axial runout may occur in piston P. Even in that case, the piston P moves back and forth while in close contact with the housing H, A predetermined gap is provided between the inner surface of the sing H and the piston P, and a seal ring 5 is provided between them. The close contact state is maintained.

[0043] In this configuration, the second output shaft A2 rotates with axial runout due to the change in the attitude of the piston P. This affects the gear unit U to which the second output shaft A2 is mated, and the rotation of the gear unit U There is a possibility that the rotation drive will not be maintained smoothly. However, in this configuration, the gear unit U and H A gap is actively provided between the wedge H and the gear unit U to allow for axial runout, and the electric Cylinder D can be operated smoothly.

[0044] (Radial gap) In this embodiment, in particular, an active gap is created between the outer surface of the outer member 4 and the inner surface of the housing H. A gap L1 is provided. Specifically, as shown in Figure 2(a), among the inner surfaces of the housing H The outer surface of the outer member 4 and the portion facing the outer surface of the second gear G2 are made into a cylindrical surface, and the outer member The outer diameter of the outer surface of 4 is made smaller than the outer diameter of the outer surface of the second gear G2. Therefore, the gap L1 between the cylindrical surface and the outer member 4 is larger than the gap L2 between the cylindrical surface and the second gear G2. A large amount will definitely be secured.

[0045] As a result of the formation of this gap, the gear unit U and piston P are as shown in the lower part of Figure 1. The first gear G1 and the second gear G2 can pivot around the position near the engagement point. The space between the piston P and the inner surface of the housing H is sealed by a seal ring 5, and the outer surface of the piston P The surface and the inner surface of the housing H are configured so that they do not come into direct contact. Therefore, as described above, The gear unit U and piston P can oscillate sufficiently.

[0046] The gap L1 between the outer member 4 and the inner surface of the housing H is formed to be approximately 80 μm, for example. Incidentally, in a typical mechanical structure, the outer ring of the bearing is inserted into the bearing without any play. The gap size when placing them is approximately 5 to 10 μm.

[0047] This results in shape errors in the second gear G2 or gear unit U, or gear unit If there are shape errors or mounting errors in other parts such as spacer S that are further connected to knit U However, it is possible to accommodate the gear unit U in the housing H while absorbing these various errors. Furthermore, when driving the gear unit U and piston P, if any of the components come into contact with each other... There is no interference at a constant rotation angle, and load fluctuations occur due to the rotation of motor M. This can prevent the above. Furthermore, the outer member 4 that performs the bearing function is not completely fixed. This eliminates the need for tasks such as fixing the outer member 4 to the housing H, which was previously required. For example, welding processes can be eliminated, preventing the occurrence of thermal distortion caused by welding. .

[0048] (Gap in the direction along the axis) In this embodiment, the outer member 4 is movable by a predetermined distance along the direction of the axis X. Therefore, between the outer member 4 and the second gear G2, and between the outer member 4 and the space A gap L3 is actively formed between the spacer S and the housing H, or between the spacer S and the housing H. Specifically, the outer member 4 is designed to move approximately 300-400 μm along the axis X. This configuration makes it easier to change the attitude of the gear unit U and piston P. ru.

[0049] (Gap-forming structure between each component) Furthermore, in the rotational support structure of this embodiment, even when the gear unit U changes its orientation... The components constituting the gear unit U and the second gear G2 are arranged so as not to interfere with each other. Specifically, the pivot 2 and the first gear G1 rotate together, while the axle rotates relative to them. Interference with the Uta component 4 or the second gear G2 is prevented.

[0050] Specifically, as shown in Figure 2(b), interference between the pivot 2 and the second gear G2 is first prevented. In a view perpendicular to the axis Xg1 of the first gear G1, the second gear G2 and the pivot 2 and They are positioned spaced apart in the direction of extension of the axis X. That is, in Figure 2(b), the second The right end face of gear G2 and the left end face of the pivot 2 are spaced L4 apart along the direction of the axis Xg1. This spacing L4 is mainly the end face of the outer member 4 facing the second gear G2. It is formed by the distance at which the end face of the pivot support 2 facing the first gear G1 retracts from the surface.

[0051] This means that even if the pivot support 2 is misaligned toward the second gear G2, the outer Member 4 contacts the second gear G2, and the pivot 2 is in a predetermined relative position with the outer member 4 via the ball 1. Because it maintains its position, the left end face of the pivot 2 is always aligned with the end face of the outer member 4. This position is away from G2. As a result, the second gear G2 and the pivot 2 never interfere with each other. This is the result.

[0052] Furthermore, there is concern that the rotating pivot 2 may come into contact with the spacer S. However, in Figure 2(b), the right end of the pivot support 2 that faces the spacer S is the outer member 4 The end face of the gear facing the spacer S is configured to recede towards the first gear G1. In other words, the length L5 of the outer member 4 along the axis Xg1 is greater than the length L6 of the outer surface of the pivot portion 2. The structure is made narrow, and both end faces of the pivot support 2 are recessed relative to both end faces of the outer member 4. This prevents the pivot point 2 from interfering with the spacer S.

[0053] Furthermore, as shown in Figure 2(b), to prevent interference between the first gear G1 and the outer member 4, Therefore, the inner diameter of the outer member 4 is made larger than the outer diameter of the first gear G1, and there is a gap between them. L7 is provided. In this configuration, the outer member 4 and the first gear G1 are on the axis Xg1. There are no overlapping parts when viewed along the direction. Therefore, hypothetically, between the pivot support 2 and the outer member 4 Ball 1 becomes loose, and the first gear G1 moves in the direction of the axis Xg1 relative to the outer member 4. Even when moving along it toward the outer member 4, the first gear G1 and the outer member 4 do not interfere with each other. It won't happen.

[0054] As described above, with this configuration, in order to avoid interference between members that rotate relative to each other, for example The position of the meshing diameter between the first gear G1 and the second gear G2, and the part that exhibits bearing function. The diameter dimension (PCD: Pitch Circle Diameter), that is, the radial position of ball 1, is precisely determined. This eliminates the need to pre-determine placement, significantly expanding the acceptable range for component dimensions or installation locations. Therefore, interference between rotating members is less likely to occur, and a highly reliable rotating support member can be obtained. Cut.

[0055] As described above, with this configuration, the configuration of the gear unit U and piston P is simplified while... A rotational support structure for the electric cylinder D that appropriately outputs the output of the M can be obtained.

[0056] [Second Embodiment] As shown in Figure 3, a harmonic drive gear mechanism can also be used as the reduction mechanism K. Output shaft A The wave generator W1 engages with 1, and a pressing device is provided at the tip of the wave generator W1. Roller W2 presses the outer teeth of flexspline W3 radially outward. The outer teeth are It engages with the circular spline W4 positioned on the side. (Of the flexsplines W3, the outer teeth...) A boss portion W3a is formed at the opposite end, and a bearing B is fitted onto the boss portion W3a. Therefore, it is pivotally supported by the housing H. The first implementation is located in the central fitting hole W3b of the boss portion W3a. A second output shaft A2, similar to the form, is fitted into this fitting hole W3b. Serrations or other features should be provided to allow for rotation.

[0057] In this case, the wave generator W1 will be included in the output shaft A1, and the flexp The external teeth of line W3 correspond to the first gear G1. Circular spline W4 corresponds to the second gear G2. This corresponds to the bearing B of the boss portion W3a, which is the outer member 4 in the first embodiment. and corresponds to the shaft support 2 to which ball 1 is attached. In other words, flexspline W3 and bearing The gear unit U is composed of ng B.

[0058] In this embodiment, the outer ring of bearing B is positioned along both sides of the axis X. Between the end face and the side of the housing H or circular spline W4, or the bearing Between the outer ring Ba and the inner surface of the housing H, or between the inner ring of bearing B A predetermined gap L1 is actively provided between the Bb and the boss portion W3a of the flexspline W3. put.

[0059] Flexspline W3 is inherently elastically deformable, and different axes are formed in each part. There is a possibility that the position may be restricted by the tooth contact with the circular spline W4. The axis X1 formed by the region of the external tooth and the axis formed by the region of the boss W3a at the opposite end X2 may be non-parallel. Therefore, if the bearing B supporting the boss W3a is Even when the component is securely fixed to the jingle H without any play, rotation may occur due to dimensional errors in the part, etc. It can handle defects.

[0060] However, as in this embodiment, the bearing B that supports the boss portion W3a is actively positioned By making it possible to change the momentum, the rotation of the Flexspline W3 can be made even smoother. Cut.

[0061] [Other Embodiments] In each of the above embodiments, a gap L1 is provided between the outer member 4 and the inner surface of the housing H. However, as another configuration, for example, a predetermined gap is provided between the ball 1 and the outer member 4. This is possible. In this case, the outer member 4 and the inner surface of the housing H are welded together or the outer member 4 is fixed to the inner surface of the housing H. The component 4 is screwed into and fixed to the inner surface of the housing H, or further fixed with bolts. It's okay if you do. [Industrial applicability]

[0062] The rotational support structure for the electric cylinder of the present invention significantly reduces the rotational speed of the motor while driving rotation It can be widely used as a device to transmit power to other driven objects. [Explanation of Symbols]

[0063] 1 ball 2 axis branch 23 Recess 4 Outer members A1 Output shaft A1a Inclined section D Electric Cylinder G1 1st Gear G2 2nd Gear H Housing K reduction mechanism M Motor U Gear Unit X-axis center

Claims

1. A cylindrical housing, A motor having an output shaft is mounted on the aforementioned housing, The housing is equipped with a reduction mechanism that is built into the housing and connected to the output shaft, The aforementioned reduction mechanism, A gear unit having a first gear that rotates driven by the output shaft on one side, and a shaft support that rotates together with the first gear and has an outer member and a ball mounted on it that face the inner surface of the housing on the other side, The housing comprises an annular second gear fixed to the inner surface of the housing and meshing with the first gear, In a view perpendicular to the axis of the output shaft, the second gear and the shaft support are spaced apart in the direction extending from the axis, and in a view along the axis, the outer member and the first gear are spaced apart radially. The outer member is movable in a direction along the axis and can come into contact with the second gear. The side surface of the shaft support facing the second gear is spaced further away from the second gear than the side surface of the outer member facing the second gear. Rotation support structure for electric cylinder.

2. The rotational support structure for an electric cylinder according to claim 1, wherein the length of the shaft support portion in the direction of extension of the axis is shorter than the length of the outer member, with respect to the shaft support portion and the outer member facing each other with respect to the ball in between.

3. The gear unit is a planetary gear mechanism, the first gear is a planetary gear, the shaft support is a carrier supporting a plurality of the planetary gears, and the output shaft is a sun gear. The tip of the output shaft is provided with a tapered inclined portion. The rotational support structure for an electric cylinder according to claim 1 or 2, wherein a recess for accommodating the inclined portion is provided at a position in the shaft support facing the output shaft.

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