Speed reducer, drive unit, and steering assist device

Abstract

This invention provides a speed reducer, a drive unit, and a steering assist device. One embodiment of the speed reducer includes: an input rotating body, a base block, a speed reduction mechanism, and a cylindrical housing. The input rotating body receives power from a drive device and rotates. The base block supports the input rotating body so that it can rotate. The speed reduction mechanism reduces the rotation of the input rotating body. The cylindrical housing covers the outer periphery of the speed reduction mechanism and the base block, and is assembled to the base block in a manner that allows it to rotate relative to the base block. The speed reducer outputs the rotation reduced by the speed reduction mechanism from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from a radially inner region of the cylindrical housing toward a position radially outer than the outer periphery of the cylindrical housing.

Description

Technical Field

[0001] This invention relates to speed reducers, drive units, and steering assist devices. Background Technology

[0002] As a device in a vehicle's steering system, steering assist devices that utilize hydraulic or electric motor forces to assist the driver's steering operations are known. A steering assist device includes: a steering mechanism that steers the wheels according to the operation of a steering unit (steering wheel); and a drive unit that outputs an assist force to the steering mechanism corresponding to the control force applied to the steering unit. (See, for example, Patent Document 1)

[0003] The drive unit used in the aforementioned steering assist device includes a drive device such as an electric motor and a reducer that slows down the output of the drive device. The reducer is configured to include: an input rotating body that receives power from the drive device and rotates; a reduction mechanism that slows down the rotation of the input rotating body; and an output rotating body that receives the power slowed down by the reduction mechanism and rotates. The reducer transmits the rotation of the output rotating body to the steering mechanism.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-35475 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] As a speed reducer used in steering assist devices, there exists a speed reducer having the following components: an input rotating body; a base block that supports the input rotating body so that it can rotate; a speed reduction mechanism that reduces the rotation of the input rotating body; and a cylindrical housing that covers the outer periphery of the speed reduction mechanism and the base block and is rotatably assembled to the base block.

[0009] For this reducer, when the base block is mounted on an external fixed component such as a vehicle body mounting section, the cylindrical housing rotates as an output rotating body. Conversely, when the cylindrical housing is mounted on an external fixed component such as a vehicle body mounting section, the base block rotates as an output rotating body.

[0010] In this type of reducer, in order to mount the base block to an external fixed component, a fixing flange component is mounted on the axial end face of the base block, and the flange component is mounted to the fixed component using bolts or the like. In other words, the reducer is constructed by mounting an independent fixing flange component on the axial end face of the base block in a manner that overlaps with the base block.

[0011] Therefore, for this reducer, the increased overall axial length and the corresponding amount of the independent flange members mounted on the end face of the base block in an overlapping manner make it difficult to meet the requirements for miniaturization of the reducer as a whole. In addition, the number of components in the reducer also increases.

[0012] The present invention provides a speed reducer, a drive unit, and a steering assist device that can reduce the number of parts and shorten the axial length.

[0013] Solution for solving the problem

[0014] (1) A speed reducer according to one embodiment of the present invention comprises: an input rotating body that receives power from a drive device and rotates; a base block that supports the input rotating body to enable rotation; a speed reduction mechanism that reduces the rotation of the input rotating body; and a cylindrical housing that covers the outer peripheral sides of the speed reduction mechanism and the base block, and is assembled to the base block in a manner that allows it to rotate relative to the base block. The rotation reduced by the speed reduction mechanism is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from the radially inner region of the cylindrical housing toward a position radially outer than the outer peripheral surface of the cylindrical housing.

[0015] (2) Alternatively, the base block may have an annular groove that opens axially between the base plate portion disposed radially inside the cylindrical housing and the fixing flange. Alternatively, one axial end of the cylindrical housing may be accommodated within the annular groove.

[0016] (3) Alternatively, a sealing member is provided between the inner circumferential surface of the annular groove and the outer circumferential surface of the cylindrical shell to seal the base block and the cylindrical shell.

[0017] (4) Another aspect of the present invention provides a speed reducer comprising: a crankshaft having an eccentric rotating portion, the crankshaft receiving power from a drive device and rotating thereon; a base block supporting the crankshaft for rotation; an oscillating gear receiving the eccentric rotation of the eccentric rotating portion of the crankshaft and oscillating thereon; and a cylindrical housing having an internal tooth having a number of teeth different from the number of teeth of the external teeth of the oscillating gear, rotatably assembled to the base block while covering the outer peripheral side of the oscillating gear and the base block. Rotation reduced by the oscillating rotation of the oscillating gear is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block extending from the radially inner region of the cylindrical housing toward a position radially outer than the outer peripheral surface of the cylindrical housing.

[0018] (5) A driving unit according to one embodiment of the present invention comprises: a driving device that outputs rotational power; and a reducer that receives power from the driving device and reduces the input rotation. The reducer comprises: an input rotating body that receives power from the driving device and rotates; a base block that supports the input rotating body to be rotatable; a reduction mechanism that reduces the rotation of the input rotating body; and a cylindrical housing that covers the outer peripheral sides of the reduction mechanism and the base block, and is assembled to the base block in a manner that allows it to rotate relative to the base block. The rotation reduced by the reduction mechanism is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from the radially inner region of the cylindrical housing toward a position radially outer than the outer peripheral surface of the cylindrical housing.

[0019] (6) A steering assist device according to one embodiment of the present invention comprises: a drive unit that outputs rotational power; a reducer that receives power from the drive unit and reduces input rotation; and a steering mechanism that receives power reduced by the reducer and operates accordingly. The reducer comprises: an input rotating body that receives power from the drive unit and rotates; a base block that supports the input rotating body for rotation; a reduction mechanism that reduces the rotation of the input rotating body; and a cylindrical housing that covers the outer periphery of the reduction mechanism and the base block, and is assembled to the base block in a manner that allows rotation relative to the base block. The rotation reduced by the reduction mechanism is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from a radially inner region of the cylindrical housing toward a position radially outer than the outer periphery of the cylindrical housing.

[0020] The effects of the invention

[0021] In the aforementioned reducer, a fixing flange extending radially outward from the radially inner region of the cylindrical housing towards a position radially outer than the outer circumferential surface of the cylindrical housing is integrally formed with the base block. Therefore, compared to mounting a separate fixing flange member on the end face of the base block, the number of parts can be reduced, and the situation where the fixing flange occupies a large area in the axial direction of the reducer can be avoided. Thus, by employing this reducer, it is possible to reduce the number of parts and shorten the axial length. Attached Figure Description

[0022] Figure 1 This is a schematic schematic diagram of the steering assist device according to an embodiment of the present invention.

[0023] Figure 2 This is a longitudinal sectional view of the speed reducer according to the first embodiment.

[0024] Figure 3 This is a longitudinal sectional view of the reducer according to the second embodiment.

[0025] Figure 4 This is a longitudinal sectional view of the reducer according to the third embodiment.

[0026] Figure 5 This is a longitudinal sectional view of the reducer according to the fourth embodiment.

[0027] Figure 6 This is a longitudinal sectional view of the reducer according to the fifth embodiment.

[0028] Explanation of reference numerals in the attached figures

[0029] 1. Steering assist device; 6. Steering mechanism; 8. Motor (drive unit); 10. Drive unit; 11. Reducer; 12. Base block; 12Aa. Base plate; 12Ab. Fixing flange; 13. Crankshaft (input rotating body); 14A. First oscillating gear (oscillating gear, reduction mechanism); 14B. Second oscillating gear (oscillating gear, reduction mechanism); 15. Cylindrical housing; 21. Internal toothed pin (reduction mechanism); 28. Sealing member; 60. Annular groove. Detailed Implementation

[0030] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0031] <Steering Assist Device>

[0032] Figure 1 This is a schematic diagram of the steering assist device 1 of a vehicle that uses the drive unit 10 of this embodiment.

[0033] The steering assist device 1 includes: a steering wheel 2; a steering shaft 3; a drive unit 10, which also serves as a steering transmission unit; and a steering mechanism 6, which uses the drive unit 10 to steer.

[0034] The steering wheel 2 is positioned in front of the driver's seat and is operated by the driver. The steering shaft 3 is integrated with the steering wheel 2 and rotates together with the steering wheel 2.

[0035] The drive unit 10 includes: a motor 8, which is a drive device for steering assistance; and a reducer 11 (111, 211, 311, 411), which reduces the rotation of the motor 8 and transmits it to the steering mechanism 6.

[0036] The drive unit 10 is connected to the lower end of the steering shaft 3. The steering torque transmitted from the steering wheel 2 to the steering shaft 3 is input to the input section of the reducer 11 via a gear mechanism (not shown). The input section of the reducer 11 combines the input steering torque with the auxiliary torque generated by the motor 8 and transmits the combined torque to the reduction mechanism section. Therefore, the combined steering torque and auxiliary torque are reduced at a predetermined reduction ratio and output to the output section of the reducer 11 (steering mechanism 6 side).

[0037] A torque sensor (not shown) is installed on the steering shaft 3. The torque detected by the torque sensor is input to a controller (not shown) for controlling the motor 8. The controller controls the output of the motor 8 based on the input signal from the torque sensor. Steering by the driver using the steering wheel 2 is assisted by the torque of the motor 8 controlled by the controller.

[0038] An output arm 27, which will be discussed later, is provided on the output side of the reducer 11. The top end of the output arm 27 is connected to the vehicle's steering mechanism 6. The steering mechanism 6 includes: an operating arm 6a, which receives operating force from the output arm 27; and a steering tie rod 6b, which steers the front wheels W of the vehicle according to the operation of the operating arm 6a.

[0039] The reducers 11, 111, 211, 311, and 411 of the various embodiments described below can be used in... Figure 1 The steering assist device 1 shown.

[0040] <First Embodiment>

[0041] Figure 2 This is a view showing a longitudinal section of the reducer 11 according to the first embodiment.

[0042] The reducer 11 includes: a base block 12 fixedly mounted on the vehicle; a plurality of (e.g., three) crankshafts 13 (input rotating bodies) rotatably supported on the base block 12; a first oscillating gear 14A and a second oscillating gear 14B oscillating and rotating together with two eccentric rotating portions 13b of each crankshaft 13; and a cylindrical housing 15 rotatably supported on the outer peripheral surface of the base block 12 in a manner that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B.

[0043] The base block 12 is formed as a short-axis cylinder.

[0044] For ease of explanation, the direction along the central axis O1 of the base block 12 will be referred to as the axial direction, and the radial direction centered on the central axis O1 will be referred to as the radial direction. Furthermore, regarding the axial direction, there are cases where the side facing inwards toward the object is referred to as the axial inner side, and the opposite side of that axial inner side is referred to as the axial outer side. These designations will also be used in the description of other embodiments.

[0045] The base block 12 includes a first base block 12A disposed on one side in the axial direction and a second base block 12B disposed on the other side in the axial direction.

[0046] The first base block 12A has a circular plate-shaped base plate portion 12Aa and a fixing flange 12Ab extending radially outward from the outer periphery of the base plate portion 12Aa. The fixing flange 12Ab is integrally formed with the base plate portion 12Aa of the first base block 12A by casting or the like. The fixing flange 12Ab extends radially outward relative to the outer peripheral surface of the cylindrical shell 15.

[0047] The first base block 12A has an annular groove 60 that opens toward the other side (the side of the second base block 12B) in the axial direction between the base plate portion 12Aa and the fixing flange 12Ab.

[0048] The fixing flange 12Ab has a thin-walled relay portion 12Ab1 forming the bottom wall of the annular groove 60 and a flange main body portion 12Ab2 disposed radially outside the relay portion 12Ab1. The flange main body portion 12Ab2 is formed to have a thickness equal to that of the substrate portion 12Aa. The annular groove 60 is formed such that it is surrounded by the outer peripheral surface of the substrate portion 12Aa, the relay portion 12Ab1 of the fixing flange 12Ab, and the flange main body portion 12Ab2.

[0049] A bolt insertion hole 40 is formed in the flange body 12Ab2, extending axially through the flange body 12Ab2. A bolt for fixing a vehicle body (not shown) is inserted into the bolt insertion hole.

[0050] A cylindrical wall 61 protruding axially upwards from the relay section 12Ab1 is formed. The housing section 8a of the motor 8 is fixed to the end of the cylindrical wall 61 by bolts 62.

[0051] The second base block 12B has: a circular plate-shaped base plate portion 12Ba, which is formed to have an outer diameter that is approximately the same as the outer diameter of the base plate portion 12Aa of the first base block 12A; and a plurality of connecting pillars 12Bb, which extend from the end face of the base plate portion 12Ba toward the first base block 12A.

[0052] Multiple (e.g., three) of the connecting pillars 12Bb are arranged on the end face of the substrate portion 12Ba in a concentric circle centered on the central axis O1.

[0053] With the end face of the connecting post 12Bb in contact with the end face of the base plate portion 12Aa of the first base block 12A, each connecting post 12Bb is fastened to the first base block 12A using bolts 16, thereby assembling the second base block 12B with the first base block 12A. Furthermore, Figure 2Reference numeral 17 in the figure is a locating pin used to position the first base block 12A to each connecting support column 12Bb before fastening with bolts 16.

[0054] An axial gap is ensured between the base plate portion 12Aa of the first base block 12A and the base plate portion 12Ba of the second base block 12B. A first oscillating gear 14A and a second oscillating gear 14B are disposed within this gap. Multiple clearance holes 18 are formed in the first oscillating gear 14A and the second oscillating gear 14B for the connecting supports 12Bb of the second base block 12B to pass through. The clearance holes 18 are formed sufficiently large relative to the outer diameter of the connecting supports 12Bb so that the connecting supports 12Bb do not obstruct the oscillating rotation of the first oscillating gear 14A and the second oscillating gear 14B.

[0055] The cylindrical housing 15 is disposed across the outer peripheral surfaces of the base plate portion 12Aa of the first base block 12A and the base plate portion 12Ba of the second base block 12B. The axially oriented edges of the cylindrical housing 15 are rotatably supported on the outer peripheral surfaces of the base plate portion 12Aa of the first base block 12A and the base plate portion 12Ba of the second base block 12B by means of bearings 19.

[0056] The edge of the cylindrical housing 15 on one side along the axial direction is supported on the outer peripheral surface of the base plate portion 12Aa by means of a bearing 19 in the annular groove 60 of the first base block 12A.

[0057] In addition, such as Figure 1 As shown, an output arm 27 extending radially outward is integrally formed on the outer peripheral surface of the cylindrical housing 15.

[0058] A plurality of pin grooves 20 are formed on the inner circumferential surface of the central region (the region opposite to the outer circumferential surfaces of the first oscillating gear 14A and the second oscillating gear 14B) in the axial direction of the cylindrical housing 15. These grooves extend parallel to the central axis O1 of the first base block 12A and the second base block 12B.

[0059] Each pin groove 20 rotatably houses a generally cylindrical internal toothed pin 21. The plurality of internal toothed pins 21 mounted on the inner circumferential surface of the cylindrical housing 15 are opposite to the outer circumferential surfaces of the first oscillating gear 14A and the second oscillating gear 14B.

[0060] The first oscillating gear 14A and the second oscillating gear 14B are formed with an outer diameter slightly smaller than the inner diameter of the cylindrical housing 15. The outer peripheral surface of the first oscillating gear 14A has an outer tooth 14Aa that contacts a plurality of internal tooth pins 21 disposed on the inner peripheral surface of the cylindrical housing 15 in an engaged state.

[0061] The outer peripheral surface of the second oscillating gear 14B has an outer tooth 14Ba that contacts a plurality of internal tooth pins 21 disposed on the inner peripheral surface of the cylindrical housing 15 in an engaged state.

[0062] The number of teeth on the external teeth 14Aa and 14Ba is set to be slightly less than the number of internal teeth 21 (slots 20) (e.g., one less).

[0063] Multiple crankshafts 13 are arranged on the same circumference centered on the central axis O1 of the first base block 12A and the second base block 12B. Each crankshaft 13 is rotatably supported on the first base block 12A and the second base block 12B by means of bearings 22.

[0064] Each crankshaft 13 has a pair of journals 13a formed in a manner that are axially separated. Each journal 13a is supported by a bearing 22. The aforementioned two eccentric rotating portions 13b are arranged between the pair of journals 13a of each crankshaft 13.

[0065] A gear mounting portion 13c is formed at one end of the crankshaft 13 along its axial direction (the side where the motor 8 is mounted) adjacent to the journal 13a. The gear mounting portion 13c protrudes axially outward relative to the base plate portion 12Aa of the first base block 12A. A crankshaft gear 24 that meshes with the output gear 23 of the motor 8 is mounted in the gear mounting portion 13c.

[0066] At steering axis 3 (refer to) Figure 1 The gears of the gear mechanism (not shown) formed mesh with the crankshaft gear 24. Therefore, the driver's operating force on the steering wheel 2 is input to the crankshaft 13 via the crankshaft gear 24, and the auxiliary force from the motor 8 is also input to the crankshaft 13 via the crankshaft gear 24 at the same time.

[0067] The first oscillating gear 14A and the second oscillating gear 14B each have a support hole 25 through which the corresponding eccentric rotating portion 13b of the crankshaft 13 passes. An eccentric bearing 26 (cylindrical roller bearing) is provided in each support hole 25 of the first oscillating gear 14A and the second oscillating gear 14B. Thus, the first oscillating gear 14A and the second oscillating gear 14B are supported on the corresponding eccentric rotating portion 13b of the crankshaft 13 by means of the eccentric bearing 26.

[0068] For the reducer 11, if torque is received from the steering shaft 3 and the motor 8 to rotate the multiple crankshafts 13 in one direction, the eccentric rotating portions 13b of each crankshaft 13 rotate in the same direction with a predetermined radius. Furthermore, as each eccentric rotating portion 13b rotates, the first oscillating gear 14A and the second oscillating gear 14B oscillate and rotate in the same direction with the same radius. At this time, the external teeth 14Aa of the first oscillating gear 14A and the external teeth 14Ba of the second oscillating gear 14B contact the multiple internal toothed pins 21 held on the inner circumference of the cylindrical housing 15 in a manner that they mesh with each other.

[0069] For the reducer 11, the number of teeth on the external teeth 14Aa of the first oscillating gear 14A and 14Ba of the second oscillating gear 14B is set to be slightly less than the number of internal pins 21 on the cylindrical housing 15. Therefore, during one revolution of the first oscillating gear 14A and the second oscillating gear 14B, the external teeth 14Aa of the first oscillating gear 14A and 14Ba of the second oscillating gear 14B push the cylindrical housing 15 in the same direction at a predetermined interval. As a result, the rotation of the crankshaft 13 is reduced at a predetermined reduction ratio and output as the rotation of the cylindrical housing 15.

[0070] Furthermore, in this embodiment, the crankshaft 13 constitutes the input rotating body of the reducer 11. In addition, the first oscillating gear 14A and the second oscillating gear 14B, together with the internal gear pin 21, constitute the reduction mechanism of the reducer 11.

[0071] At one end of the cylindrical housing 15 on the axial side, the outer circumferential surface of the cylindrical housing 15 and the inner circumferential surface of the annular groove 60 are sealed by a sealing member 28. The sealing member 28 is configured within the annular groove 60 to be located radially outside the bearing 19, separated from the circumferential wall of the cylindrical housing 15. In other words, the sealing member 28 and the bearing 19 are configured to overlap axially within the annular groove 60.

[0072] On the other hand, at the other end of the cylindrical housing 15 on the other side in the axial direction, the inner circumferential surface of the cylindrical housing 15 and the outer circumferential surface of the base plate portion 12Ba of the second base block 12B are sealed by the same sealing member 28.

[0073] The space surrounded by the cylindrical shell 15 and the base block 12, and in which the speed reduction mechanism is disposed, is filled with lubricating fluid for lubricating the speed reduction mechanism and other mechanical moving parts.

[0074] As described above, in the reducer 11 of this embodiment, the fixing flange 12Ab, which extends from the radially inner region of the cylindrical housing 15 toward a position radially outer than the outer peripheral surface of the cylindrical housing 15, is integrally formed with the first base block 12A (base block 12). Therefore, compared to the case where a separate fixing flange member is mounted on the end face of the base block, the number of parts can be reduced, and the situation where the fixing flange occupies a large area in the axial direction of the reducer 11 is avoided. Therefore, when the reducer 11 of this embodiment is adopted, it is possible to reduce the number of parts and shorten the axial length.

[0075] Furthermore, in the reducer 11 of this embodiment, an annular groove 60 with an axial opening is formed between the base plate portion 12Aa of the first base block 12A disposed radially inside the cylindrical housing 15 and the fixing flange 12Ab. Moreover, one axial end of the cylindrical housing 15 is accommodated in the annular groove 60.

[0076] Therefore, when the reducer 11 of this embodiment is adopted, the cylindrical housing 15 and a portion of the fixing flange 12Ab can be arranged to overlap in the axial direction, thus further shortening the axial length of the reducer 11. In addition, the reducer 11 according to this embodiment can sufficiently ensure the wall thickness of the flange main body 12Ab2 that is to be fastened to the vehicle body side.

[0077] Furthermore, in the reducer 11 of this embodiment, a sealing member 28 is disposed between the inner circumferential surface of the annular groove 60 and the outer circumferential surface of the cylindrical housing 15 to seal the first base block 12A (base block 12) and the cylindrical housing 15. Therefore, a seal between the first base block 12A and the cylindrical housing 15 can be achieved at a position where it overlaps with the bearing 19 in the axial direction. Consequently, with this structure, the axial length of the reducer 11 can be further shortened.

[0078] Furthermore, in the above embodiment, the base block 12 is fixed to the vehicle body side, and the cylindrical housing 15 is configured as an output rotating body, but this is not a limitation. For example, it is also possible to fix the cylindrical housing 15 to the vehicle body side and configure the base block 12 side as an output rotating body, contrary to this embodiment.

[0079] In the embodiments described below, the same reference numerals are used for parts that are common to the first embodiment.

[0080] <Second Implementation>

[0081] Figure 3 This is a view showing a longitudinal section of the reducer 111 according to the second embodiment.

[0082] The reducer 111 of this embodiment includes: a base block 12 fixed to a vehicle; a plurality of crankshafts 13 (input rotating bodies) supported on the base block 12 in a rotatable manner; a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13; and a cylindrical housing 15 that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B.

[0083] A pin groove 20 is formed on the inner circumferential surface of the cylindrical housing 15. An internal toothed pin 21 is held in the pin groove 20. The internal toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a speed reduction mechanism. These basic structures are the same as those in the first embodiment.

[0084] The base block 12 has a first base block 12A disposed on one side in the axial direction and a second base block 12B disposed on the other side in the axial direction. With the connecting post 12Bb abutting against the base plate portion 12Aa of the first base block 12A, the connecting post 12Bb is fixed to the base plate portion 12Aa by bolts 16, thereby combining the second base block 12B with the first base block 12A.

[0085] A fixing flange 12Ab extends radially outward from the base plate portion 12Aa of the first base block 12A, relative to the outer peripheral surface of the cylindrical housing 15. An annular groove 60 is formed in the fixing flange 12Ab. One axial end of the cylindrical housing 15 is accommodated in the annular groove 60. The structure of the fixing flange 12Ab and the end of the cylindrical housing 15 is the same as that in the first embodiment.

[0086] In addition, the inside of the reducer 111 is filled with lubricating fluid for lubricating mechanical moving parts such as the reduction gear mechanism.

[0087] One of the multiple crankshafts 13 protrudes axially outward relative to the bearing 22 that supports the journal 13a located on the opposite side of the axial direction. The protruding portion of the crankshaft 13 is referred to as the protrusion 13d.

[0088] A recess 65 is formed in the base plate portion 12Ba of the second base block 12B to accommodate the protrusion 13d of the crankshaft 13. A rotation detection device 41 for detecting the rotational state (rotational position, rotational speed) of the crankshaft 13 is provided between the inner wall of the recess 65 and the protrusion 13d of the crankshaft 13.

[0089] The rotation detection device 41 includes a detection target 42 mounted on the outer peripheral surface of the protrusion 13d of the crankshaft 13 and a target detection part 43 mounted on the inner wall of the recess 65 of the second base block 12B.

[0090] The target detection unit 43 outputs a signal corresponding to the rotation of the crankshaft 13 to the controller 100. As the rotation detection device 41, for example, a magnetic detection device or an optical detection device can be used. The target detection unit 43 of the rotation detection device 41 is mounted on the inner wall of the recess 65 such that the detection surface faces the detection target 42 with a small gap between them.

[0091] The signal input from the rotation detection device 41 to the controller 100 can be used for, for example, to identify and respond to situations where the output of the auxiliary signal (drive signal) to the motor 8 has stopped for some reason, and to correct situations where the output target of the motor 8 deviates from the actual rotation. When the controller 100 identifies that the output of the auxiliary signal (drive signal) to the motor 8 has stopped, the controller 100 releases, for example, the reaction force of the motor 8 acting on the reducer 111. This prevents the manual steering operation performed by the driver from being hindered by the reaction force of the motor 8.

[0092] A sealing member 39 is disposed between the outer peripheral surface of the base side region of the protrusion 13d of the crankshaft 13 and the inner peripheral surface of the recess 65 of the second base block 12B to seal the crankshaft 13 and the second base block 12B. The interior of the recess 65 of the second base block 12B is divided by the sealing member 39 into a bottom region for the rotation detection device 41 and a lubrication region for the bearing 22. Lubricating fluid from the reducer 111 flows into the lubrication region. Furthermore, the flow of lubricating fluid from the lubrication region to the bottom region is prevented by the sealing member 39.

[0093] As described above, in this embodiment, the reducer 111 has a fixing flange 12Ab integrally formed on the first base block 12A (base block 12), extending from the radially inner region of the cylindrical housing 15 toward a position radially outer than the outer peripheral surface of the cylindrical housing 15. Therefore, compared to the case where a separate fixing flange member is mounted on the end face of the base block, the number of parts can be reduced, and the situation where the fixing flange occupies a large area in the axial direction of the reducer 111 can be avoided. Therefore, when the reducer 111 of this embodiment is adopted, it is possible to reduce the number of parts and shorten the axial length.

[0094] Furthermore, for the reducer 111 in this embodiment, a rotation detection device 41 for detecting the rotation of the crankshaft 13, which is the input rotating body, is disposed on the base block 12. Therefore, rotation information of the output side of the motor 8 can be obtained at the end side of the reducer 111, where there is ample space. Thus, without causing the motor 8 to become larger, the rotation information of the output side of the motor 8 can be effectively utilized by the controller 100.

[0095] Furthermore, in the reducer 111 of this embodiment, a recess 65 is provided in the second base block 12B (base block 12). A sealing member 39 is disposed within the recess 65 to seal the outer peripheral surface of the protrusion 13d of the crankshaft 13 with the inner peripheral surface of the recess 65. The rotation detection device 41 is disposed within the recess 65, which is separated from the lubricant inflow portion by the sealing member 39. Therefore, the inflow of lubricant into the peripheral area of ​​the rotation detection device 41 can be suppressed. Thus, by employing the reducer 111 of this embodiment, the durability of the rotation detection device 41 can be improved.

[0096] The following list other inventions that can be summarized from the second embodiment described above. That is, the following inventions are included in the second embodiment.

[0097] (2-1) A speed reducer comprising:

[0098] Base block (e.g., base block 12);

[0099] An input rotating body (e.g., crankshaft 13) receives power from a drive unit (e.g., motor 8) and rotates while supported in a rotatable manner on the base block;

[0100] The speed reduction mechanism (e.g., the first oscillating gear 14A, the second oscillating gear 14B, and the internal gear pin 21) reduces the rotation of the input rotating body.

[0101] Output rotating body (e.g., cylindrical housing 15), which receives power reduced by the speed reduction mechanism and rotates accordingly; and

[0102] A rotation detection device (e.g., rotation detection device 41) is disposed on the base block for detecting the rotational state of the shaft of the input rotating body.

[0103] (2-2) According to the reducer described in (2-1), wherein,

[0104] The base block has a recess (e.g., recess 65) for receiving the end of the output rotating body.

[0105] A sealing member (e.g., sealing member 39) is disposed inside the recess to seal the outer peripheral surface of the end of the output rotating body with the peripheral wall of the recess.

[0106] The rotation detection device is disposed on the bottom side of the recess separated by the sealing member.

[0107] (2-3) A speed reducer unit comprising:

[0108] The drive unit outputs rotational power;

[0109] and a speed reducer, which receives power from the drive unit and reduces the input rotation speed.

[0110] The reducer includes:

[0111] Base block;

[0112] The input rotating body receives power from the drive device and rotates while supported in a rotatable manner on the base block;

[0113] The deceleration mechanism reduces the rotation of the input rotating body;

[0114] An output rotating body that rotates by receiving power reduced in speed by the reduction mechanism; and

[0115] A rotation detection device, disposed on the base block, is used to detect the rotational state of the shaft of the input rotating body.

[0116] (2-4) A steering assist device comprising:

[0117] The drive unit outputs rotational power;

[0118] A speed reducer that receives power from the drive unit and reduces the input rotation speed; and

[0119] The steering mechanism receives power from the reduced speed of the reducer and operates accordingly.

[0120] The reducer includes:

[0121] Base block;

[0122] The input rotating body receives power from the drive device and rotates while supported in a rotatable manner on the base block;

[0123] The deceleration mechanism reduces the rotation of the input rotating body;

[0124] An output rotating body that rotates by receiving power reduced in speed by the reduction mechanism; and

[0125] A rotation detection device, disposed on the base block, is used to detect the rotational state of the shaft of the input rotating body.

[0126] <Third Implementation>

[0127] Figure 4 This is a view showing a longitudinal section of the reducer 211 according to the third embodiment.

[0128] The reducer 211 of this embodiment includes: a base block 12 fixed to a vehicle; a plurality of crankshafts 13 (input rotating bodies) supported on the base block 12 in a rotatable manner; a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13; and a cylindrical housing 15 that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B.

[0129] A pin groove 20 is formed on the inner circumferential surface of the cylindrical housing 15. An internal toothed pin 21 is held in the pin groove 20. The internal toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a speed reduction mechanism. These basic structures are the same as those in the first embodiment.

[0130] The base block 12 has a first base block 12A disposed on one side in the axial direction and a second base block 12B disposed on the other side in the axial direction. A fixing flange 12Ab extending radially outward from the base plate portion 12Aa of the first base block 12A extends radially outward relative to the outer peripheral surface of the cylindrical housing 15. An annular groove 60 is formed in the fixing flange 12Ab. One axial end of the cylindrical housing 15 is received in the annular groove 60. The structure of the fixing flange 12Ab and the end of the cylindrical housing 15 is the same as that of the first embodiment.

[0131] In addition, the inside of the reducer 211 is filled with lubricating fluid for lubricating mechanical moving parts such as the reduction gear mechanism.

[0132] An idler gear 64, which meshes with the crankshaft gear 24, is disposed at one axial end of the first base block 12A. The gear shaft 64a of the idler gear 64 is rotatably supported by bearings 69 and 70 (deep groove ball bearings) in a support hole 67 of the first base block 12A and a support hole 68 of the housing portion 8a of the motor 8. In the region axially outer of the bearing 70, the support hole 68 of the housing portion 8a and the gear shaft 64a of the idler gear 64 are sealed by a sealing member 54.

[0133] The outer ring 70a of the bearing 70, which is supported in the support hole 68 of the motor 8, extends longer than the inner ring 70b in the axial direction. A rotation detection device 41 for detecting the rotational state (rotational position, rotational speed) of the gear shaft 64a is provided between the portion of the outer ring 70a extending in the axial direction and the outer peripheral surface of the corresponding gear shaft 64a.

[0134] The rotation detection device 41 includes a detection target 42 mounted on the outer peripheral surface of the gear shaft 64a of the idler wheel 64 and a target detection part 43 mounted on the inner peripheral surface of the outer ring 70a of the bearing 70.

[0135] The target detection unit 43 outputs a signal to the controller 100 corresponding to the rotation of the gear shaft 64a of the idler wheel 64. For example, a magnetic detection device or an optical detection device can be used as the rotation detection device 41. The target detection unit 43 of the rotation detection device 41 is mounted on the outer ring 70a of the bearing 70 such that the detection surface faces the detection target 42 with a small gap between them.

[0136] The signal input from the rotation detection device 41 to the controller 100 can be used for, for example, to identify and respond to situations where the output of the auxiliary signal (drive signal) to the motor 8 has stopped for some reason, and to correct situations where the output target of the motor 8 deviates from the actual rotation. When the controller 100 identifies that the output of the auxiliary signal (drive signal) to the motor 8 has stopped, the controller 100 releases, for example, the reaction force of the motor 8 acting on the reducer 211. This prevents the manual steering operation performed by the driver from being hindered by the reaction force of the motor 8.

[0137] As described above, in this embodiment, the reducer 211 has a fixing flange 12Ab integrally formed on the first base block 12A (base block 12), extending radially outward from the radially inner region of the cylindrical housing 15 relative to the outer peripheral surface of the cylindrical housing 15. Therefore, compared to the case where a separate fixing flange member is mounted on the end face of the base block, the number of parts can be reduced, and the situation where the fixing flange occupies a large area in the axial direction of the reducer 211 can be avoided. Thus, when the reducer 211 of this embodiment is adopted, it is possible to reduce the number of parts and shorten the axial length.

[0138] Furthermore, in the reducer 211 of this embodiment, a rotation detection device 41 for detecting the rotational state of the gear shaft is provided on the bearing 70 of the shaft (gear shaft 64a) supporting the gear (idler 64) that rotates in conjunction with the motor 8. Therefore, rotational information from the output side of the motor 8 can be obtained from the bearing 70. Moreover, in the reducer 211 of this embodiment, the target detection part 43 of the rotation detection device 41 is mounted on the outer ring 70a of the bearing 70, and a detection target 42 is mounted on the outer circumferential surface of the gear shaft. Therefore, when using the reducer 211 of this embodiment, the rotation detection device 41 can be easily installed without occupying a large area.

[0139] The following list other inventions that can be summarized from the third embodiment described above. That is, the following inventions are included in the third embodiment.

[0140] (3-1) A speed reducer comprising:

[0141] Base block (e.g., base block 12);

[0142] An input rotating body (e.g., crankshaft 13) receives power from a drive unit (e.g., motor 8) and rotates while supported in a rotatable manner on the base block;

[0143] The speed reduction mechanism (e.g., the first oscillating gear 14A, the second oscillating gear 14B, and the internal gear pin 21) reduces the rotation of the input rotating body.

[0144] Output rotating body (e.g., cylindrical housing 15), which receives power reduced by the speed reduction mechanism and rotates accordingly; and

[0145] A rotation detection device (e.g., rotation detection device 41) is disposed on a bearing (e.g., bearing 70) of a gear shaft (e.g., gear shaft 64a) that receives power from the drive device and rotates, for detecting the rotational state of the gear shaft.

[0146] (3-2) A driving unit comprising:

[0147] The drive unit outputs rotational power;

[0148] and a speed reducer, which receives power from the drive unit and reduces the input rotation speed.

[0149] The reducer includes:

[0150] Base block;

[0151] The input rotating body receives power from the drive device and rotates while supported in a rotatable manner on the base block;

[0152] The deceleration mechanism reduces the rotation of the input rotating body;

[0153] An output rotating body that rotates by receiving power reduced in speed by the reduction mechanism; and

[0154] A rotation detection device is disposed on the bearing of a gear shaft that receives power from the drive device and rotates, for detecting the rotational state of the gear shaft.

[0155] (3-3) A steering assist device comprising:

[0156] The drive unit outputs rotational power;

[0157] A speed reducer that receives power from the drive unit and reduces the input rotation speed; and

[0158] The steering mechanism receives power from the reduced speed of the reducer and operates accordingly.

[0159] The reducer includes:

[0160] Base block;

[0161] The input rotating body receives power from the drive device and rotates while supported in a rotatable manner on the base block;

[0162] The deceleration mechanism reduces the rotation of the input rotating body;

[0163] An output rotating body that rotates by receiving power reduced in speed by the reduction mechanism; and

[0164] A rotation detection device is disposed on the bearing of a gear shaft that receives power from the drive device and rotates, for detecting the rotational state of the gear shaft.

[0165] <Fourth Implementation>

[0166] Figure 5 This is a view showing a longitudinal section of the reducer 311 according to the fourth embodiment.

[0167] The reducer 311 of this embodiment includes: a base block 12 fixed to a vehicle; a plurality of crankshafts 13 (input rotating bodies) supported on the base block 12 in a rotatable manner; a first oscillating gear 14A and a second oscillating gear 14B that oscillate and rotate in response to the rotation of the crankshafts 13; and a cylindrical housing 15 that covers the radially outer sides of the first oscillating gear 14A and the second oscillating gear 14B.

[0168] A pin groove 20 is formed on the inner circumferential surface of the cylindrical housing 15. An internal toothed pin 21 is held in the pin groove 20. The internal toothed pin 21, together with the first oscillating gear 14A and the second oscillating gear 14B, constitutes a speed reduction mechanism. These basic structures are the same as those in the first embodiment.

[0169] The base block 12 has a first base block 12A disposed on one side in the axial direction and a second base block 12B disposed on the other side in the axial direction. A fixing flange 12Ab extending radially outward from the base plate portion 12Aa of the first base block 12A extends radially outward relative to the outer peripheral surface of the cylindrical housing 15. An annular groove 60 is formed in the fixing flange 12Ab. One axial end of the cylindrical housing 15 is received in the annular groove 60. The structure of the fixing flange 12Ab and the end of the cylindrical housing 15 is the same as that of the first embodiment.

[0170] The inside of the reducer 311 is filled with lubricating fluid for lubricating mechanical moving parts such as the reduction gear mechanism.

[0171] An idler gear 64, which meshes with the crankshaft gear 24, is disposed at one axial end of the first base block 12A. The gear shaft 64a of the idler gear 64 is rotatably supported by bearings 69 in a support hole 67 of the first base block 12A and a support hole 68 of the housing portion 8a of the motor 8. In the region axially outer of the bearings 69, the support hole 68 of the housing portion 8a and the gear shaft 64a of the idler gear 64 are sealed by a sealing member 54.

[0172] A detection target 42 of the rotation detection device 41 is mounted on the outer peripheral surface of the portion of the gear shaft 64a of the idler gear 64 that protrudes axially outward relative to the sealing member 54. A target detection part 43 of the rotation detection device 41 is mounted on the housing part 8a of the motor 8, facing the support hole 68. The structure of the rotation detection device 41 is the same as that of the third embodiment.

[0173] The signal input from the rotation detection device 41 to the controller 100 can be used for, for example, to identify and respond to situations where the output of the auxiliary signal (drive signal) to the motor 8 has stopped for some reason, and to correct deviations between the output target and the actual rotation of the motor 8. When the controller 100 identifies that the output of the auxiliary signal (drive signal) to the motor 8 has stopped, the controller 100 releases, for example, the reaction force of the motor 8 acting on the reducer 311. This prevents the manual steering operation performed by the driver from being hindered by the reaction force of the motor 8.

[0174] As described above, in this embodiment, the reducer 311 has a fixing flange 12Ab integrally formed on the first base block 12A (base block 12), extending radially outward from the radially inner region of the cylindrical housing 15 relative to the outer peripheral surface of the cylindrical housing 15. Therefore, compared to the case where a separate fixing flange member is mounted on the end face of the base block, the number of parts can be reduced, and the situation where the fixing flange occupies a large area in the axial direction of the reducer 311 can be avoided. Thus, when the reducer 311 of this embodiment is adopted, it is possible to reduce the number of parts and shorten the axial length.

[0175] Furthermore, the reducer 311 of this embodiment includes a rotation detection device 41 for detecting the rotation of the gear shaft 64a of the idler wheel 64. This allows rotational information from the output side of the motor 8 to be obtained from the support portion of the gear shaft 64a of the idler wheel 64. Therefore, by employing the reducer 311 of this embodiment, the rotation detection device 41 for detecting the rotational state of the idler wheel 64 can be easily installed without occupying a large area.

[0176] <Fifth Implementation>

[0177] Figure 6 This is a view showing a longitudinal section of the reducer 411 according to the fifth embodiment.

[0178] The reducer 411 in this embodiment has a structure that is substantially the same as that of the reducer 311 in the fourth embodiment. The difference from the reducer 311 in the fourth embodiment is that the outer diameter and number of teeth of the idler gear 464 are set to be the same as the outer diameter and number of teeth of the output gear 23 of the motor 8. In this embodiment, the rotation state of the gear shaft 64a of the idler gear 464 is also detected by the rotation detection device 41.

[0179] The reducer 411 in this embodiment is designed with the same basic structure as the basic structure in the third embodiment, so it is possible to obtain the same basic effect as the basic effect in the third embodiment.

[0180] However, in the reducer 411 of this embodiment, the outer diameter and number of teeth of the idler gear 464 are set to be the same as the outer diameter and number of teeth of the output gear 23 of the motor 8. Therefore, by using the rotation detection device 41 to detect the rotational state of the gear shaft 64a of the idler gear 464, the rotational state of the motor 8 can be directly identified by the controller 100. Therefore, with this structure, the speed signal detected by the rotation detection device 41 can be directly fed back and used for the control of the motor 8. Therefore, with this structure, it is easy to perform control that matches the speed of the motor 8 with the target speed.

[0181] The following lists other inventions that can be summarized from the fourth and fifth embodiments described above. That is, the following inventions are included in the fourth and fifth embodiments.

[0182] (4-1) A speed reducer comprising:

[0183] Base block (e.g., base block 12);

[0184] An input rotating body (e.g., crankshaft 13) receives power from a drive unit (e.g., motor 8) and rotates while supported in a rotatable manner on the base block;

[0185] The speed reduction mechanism (e.g., the first oscillating gear 14A, the second oscillating gear 14B, and the internal gear pin 21) reduces the rotation of the input rotating body.

[0186] The output rotating body (e.g., cylindrical housing 15) receives power from the reduction mechanism and rotates accordingly;

[0187] An idler wheel (e.g., idler wheel 64) that rotates by meshing with a gear disposed on the input rotating body; and

[0188] A rotation detection device (e.g., rotation detection device 41) is used to detect the rotational state of the idler gear shaft (e.g., gear shaft 64a).

[0189] (4-2) The reducer according to (4-1), wherein the idler gear is configured to have the same outer diameter and number of teeth as the output gear (e.g., gear shaft 64a) of the motor.

[0190] (4-3) A driving unit comprising:

[0191] The drive unit outputs rotational power;

[0192] and a speed reducer, which receives power from the drive unit and reduces the input rotation speed.

[0193] The reducer includes:

[0194] Base block;

[0195] The input rotating body receives power from the drive device and rotates while supported in a rotatable manner on the base block;

[0196] The deceleration mechanism reduces the rotation of the input rotating body;

[0197] The output rotating body receives power from the reduction mechanism and rotates accordingly.

[0198] An idler wheel, which rotates by meshing with a gear disposed on the input rotating body; and

[0199] A rotation detection device is used to detect the rotational state of the gear shaft of the idler wheel.

[0200] (4-4) A steering assist device comprising:

[0201] The drive unit outputs rotational power;

[0202] A speed reducer that receives power from the drive unit and reduces the input rotation speed; and

[0203] The steering mechanism receives power from the reduced speed of the reducer and operates accordingly.

[0204] The reducer includes:

[0205] Base block;

[0206] The input rotating body receives power from the drive device and rotates while supported in a rotatable manner on the base block;

[0207] The deceleration mechanism reduces the rotation of the input rotating body;

[0208] The output rotating body receives power from the reduction mechanism and rotates accordingly.

[0209] An idler wheel, which rotates by meshing with a gear disposed on the input rotating body; and

[0210] A rotation detection device is used to detect the rotational state of the gear shaft of the idler wheel.

[0211] Furthermore, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from its spirit.

[0212] Industrial availability

[0213] According to the present invention, it is possible to reduce the number of parts and shorten the axial length of the reducer. Therefore, it has industrial applicability.

Claims

1. A speed reducer, wherein, This reducer has the following features: The input rotating body receives power from the drive device and rotates. A base block that supports the input rotating body so that it can rotate; The deceleration mechanism reduces the rotation of the input rotating body; as well as A cylindrical housing covers the outer periphery of the reduction mechanism and the base block, and is assembled to the base block in a manner that allows it to rotate relative to the base block. The rotation, reduced by the deceleration mechanism, is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from the radially inner region of the cylindrical shell toward a position radially outer than the outer peripheral surface of the cylindrical shell. The base block has an annular groove that opens axially between the base plate portion disposed on the radially inner side of the cylindrical shell and the fixing flange. One axial end of the cylindrical shell is housed within the annular groove. A sealing member is disposed between the inner circumferential surface of the annular groove and the outer circumferential surface of the cylindrical shell to seal the base block and the cylindrical shell. A bearing is disposed between the outer peripheral surface of the substrate and the inner peripheral surface of the cylindrical shell. The sealing member and the bearing are arranged in an axially overlapping manner within the annular groove.

2. A speed reducer, wherein, This reducer has the following features: A crankshaft having an eccentric rotating part, the crankshaft receiving power from a drive unit to rotate; A base block that supports the crankshaft so that it can rotate; The oscillating gear oscillates and rotates in response to the eccentric rotation of the eccentric rotating part of the crankshaft. as well as A cylindrical housing having an internal number of teeth different from the number of teeth on the external teeth of the oscillating gear is rotatably assembled to the base block while covering the outer periphery of the oscillating gear and the base block. The rotation, slowed down by the oscillating rotation of the oscillating gear, is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from the radially inner region of the cylindrical shell toward a position radially outer than the outer peripheral surface of the cylindrical shell. The base block has an annular groove that opens axially between the base plate portion disposed on the radially inner side of the cylindrical shell and the fixing flange. One axial end of the cylindrical shell is housed within the annular groove. A sealing member is disposed between the inner circumferential surface of the annular groove and the outer circumferential surface of the cylindrical shell to seal the base block and the cylindrical shell. A bearing is disposed between the outer peripheral surface of the substrate and the inner peripheral surface of the cylindrical shell. The sealing member and the bearing are arranged in an axially overlapping manner within the annular groove.

3. A driving unit, wherein, This drive unit has: Driven device, which outputs rotational power; and A speed reducer that receives power from the drive unit and reduces the input rotation speed. The reducer includes: An input rotating body receives power from the drive device and rotates; A base block that supports the input rotating body so that it can rotate; The deceleration mechanism reduces the rotation of the input rotating body; as well as A cylindrical housing covers the outer periphery of the reduction mechanism and the base block, and is assembled to the base block in a manner that allows it to rotate relative to the base block. The rotation, reduced by the deceleration mechanism, is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from the radially inner region of the cylindrical shell toward a position radially outer than the outer peripheral surface of the cylindrical shell. The base block has an annular groove that opens axially between the base plate portion disposed on the radially inner side of the cylindrical shell and the fixing flange. One axial end of the cylindrical shell is housed within the annular groove. A sealing member is disposed between the inner circumferential surface of the annular groove and the outer circumferential surface of the cylindrical shell to seal the base block and the cylindrical shell. A bearing is disposed between the outer peripheral surface of the substrate and the inner peripheral surface of the cylindrical shell. The sealing member and the bearing are arranged in an axially overlapping manner within the annular groove.

4. A steering assist device, wherein, The steering assist device includes: The drive unit outputs rotational power; A speed reducer that receives power from the drive unit and reduces the input rotation speed; and The steering mechanism receives power from the reduced speed of the reducer and operates accordingly. The reducer includes: An input rotating body receives power from the drive device and rotates; A base block that supports the input rotating body so that it can rotate; The deceleration mechanism reduces the rotation of the input rotating body; as well as A cylindrical housing covers the outer periphery of the reduction mechanism and the base block, and is assembled to the base block in a manner that allows it to rotate relative to the base block. The rotation, reduced by the deceleration mechanism, is output from either the cylindrical housing or the base block. A fixing flange is integrally formed on the base block, extending from the radially inner region of the cylindrical shell toward a position radially outer than the outer peripheral surface of the cylindrical shell. The base block has an annular groove that opens axially between the base plate portion disposed on the radially inner side of the cylindrical shell and the fixing flange. One axial end of the cylindrical shell is housed within the annular groove. A sealing member is disposed between the inner circumferential surface of the annular groove and the outer circumferential surface of the cylindrical shell to seal the base block and the cylindrical shell. A bearing is disposed between the outer peripheral surface of the substrate and the inner peripheral surface of the cylindrical shell. The sealing member and the bearing are arranged in an axially overlapping manner within the annular groove.

Images