JP4858393B2 - Shock absorber - Google Patents

Description

  The present invention relates to a multi-plate type shock absorber suitable for use in, for example, a starter for starting an engine.

The starter shown in Patent Document 1 employs a multi-plate type impact absorbing device.
The shock absorbing device includes a plurality of rotating disks connected to an internal gear of the planetary gear speed reducer, a plurality of fixed disks alternately arranged with the rotating disks and supported so as not to rotate, and a fixed disk. And a rotating disk, and is constituted by a disc spring or the like that applies frictional surface pressure, and each rotating disk is sandwiched between fixed disks from both sides.
When an excessive torque exceeding the sliding torque of the rotating disk is applied to the rotating disk via the internal gear, the shock absorbing device slides (rotates) against the frictional force generated between the rotating disk and the fixed disk. Thus, the internal gear is allowed to rotate and has a function of absorbing impact force.

By the way, in the above-described impact absorbing device, a large number of dimples (concave portions) are formed by pressing on the friction surfaces of both the fixed disk and the rotating disk that come into contact with each other. Thereby, since the lubricant applied to the friction surface is held by a large number of dimples, the occurrence of seizure on the friction surface can be suppressed, and the performance of the shock absorbing device can be stabilized over a long period of time.
The surface (friction surface) of the rotating disk and the fixed disk on which the dimples are formed protrudes around the dimples when the material that has flowed around the punches rises when the punch is driven to form the dimples. The part is formed.
JP 2005-113816 A

However, in the above known technique, when the dimples formed on the friction surface of the rotating disk and the dimples formed on the friction surface of the fixed disk are set at the same pitch, the protrusions formed around the dimples Wears periodically because the oil film of the lubricant is cut off at the contact portion. As wear further progresses, surface contact increases and the time for oil film breakage also increases. As a result, seizure was partially caused and the slip torque became unstable, and finally, there was a risk of reaching a locked state due to seizure.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide an impact absorbing device that can achieve improved wear resistance and stabilization of sliding torque.

(Invention of Claim 1 )
The present invention has a fixed disk and a rotating disk with which the friction surfaces come into contact with each other. When a load torque exceeding a predetermined torque is applied to the rotating disk, the rotating disk rotates (slides) against the frictional force. In the shock absorbing device that absorbs the shock, a plurality of dimples having the same shape, the same size, and the same pattern are formed on the friction surfaces of the fixed disk and the rotating disk, respectively, and fixed. The pitch P1 between the dimples formed on the disk is different from the pitch P2 between the dimples formed on the rotating disk.

According to the above configuration, since the pitch P1 between the dimples formed on the fixed disk and the pitch P2 between the dimples formed on the rotating disk are different, the protrusions formed around the dimples of both disks are The probability of periodic contact can be reduced. Thereby, since the oil film breakage of the lubricant generated by the contact between the convex portions can be reduced, the wear resistance of both discs can be improved and the life of the shock absorbing device can be extended.
Moreover, since the fluctuation of the friction coefficient between both disks can be suppressed, the sliding torque of the rotating disk can be stabilized.

(Invention of Claim 2 )
In the impact absorbing device according to claim 1, the relationship between the pitch P1 and the pitch P2 is:
P1 = P2 × (1.1 to 1.5) (1)
It is represented by the above formula (1) .
In order to effectively shift the dimple radial position of the rotating disk from the dimple radial position of the fixed disk, 1.1 or more is required. Further, in order to arrange the dimples of the rotating disk and the fixed disk with an appropriate density, 1.5 or less is required.

(Invention of Claim 3 )
In the impact absorbing device according to claim 1, the relationship between the pitch P1 and the pitch P2 is:
P2 = P1 × (1.1 to 1.5) (2)
It is represented by the above formula (2) .
In order to effectively shift the dimple radial position of the rotating disk from the dimple radial position of the fixed disk, 1.1 or more is required. Further, in order to arrange the dimples of the rotating disk and the fixed disk with an appropriate density, 1.5 or less is required.

(Invention of Claim 4 )
Any one of the shock absorbers described in claims 1 to 3 is used for a starter for starting an engine.
The starter has a function of meshing the pinion gear with the ring gear of the engine and transmitting the motor driving torque from the pinion gear to the ring gear to start the engine, so that an impact is generated when the pinion gear meshes with the ring gear. On the other hand, by using the shock absorbing device of the present invention for the starter, the shock generated when the engine is started can be absorbed by the shock absorbing device, so that it is possible to prevent damage to the strength system parts provided in the torque transmission path of the starter.

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described in detail below along with five embodiments shown in the drawings . Examples 1, 3, 4, and 5 are reference examples showing examples to which the present invention is not applied, and Example 2 is an example to which the present invention is applied.

FIG. 1 is a partial sectional view showing a contact surface between the fixed disk 49 and the rotating disk 50, and FIG. 2 is a sectional view of the starter 1.
As shown in FIG. 2, the starter 1 of this embodiment includes a motor 2 that generates a rotational force, a speed reducer 3 that decelerates the rotation of the motor 2, and an impact absorbing device that is configured in combination with the speed reducer 3. 4, a pinion shaft 6 connected to the speed reducer 3 via a clutch 5, a pinion gear 7 supported by the pinion shaft 6, and a main contact (to be described later) provided in an energization circuit (referred to as a motor circuit) of the motor 2. And an electromagnetic switch 9 having a function of moving the pinion shaft 6 in the axial direction via the shift lever 8. In FIG. 2, the upper side of the center line of the pinion shaft 6 and the electromagnetic switch 9 indicates the stopped state of the starter 1, and the lower side of the center line indicates the operating state of the starter 1.

The motor 2 includes a cylindrical yoke 10, a plurality of field coils 11 (may be permanent magnets) disposed on the inner periphery of the yoke 10, an armature 13 having a commutator 12, and rotation of the armature 13. This is a well-known DC motor constituted by a brush 14 or the like that is in sliding contact with the surface of the commutator 12.
The armature 13 has an armature core 16 that is serrated and fitted to the outer periphery of the armature shaft 15 and an armature coil 17 wound around the armature core 16. The commutator 12 is connected to individual segments. The armature shaft 15 is supported by the end frame 19 through a bearing 18 at the rear end protruding rearward from the commutator 12, and the front end protruding from the armature core 16 toward the center plate 21 through the bearing 20. It is supported (see FIG. 3).

The center plate 21 is disposed between the armature 13 and the speed reducer 3 so as to be perpendicular to the armature shaft 15 so that foreign matter such as brush powder does not scatter to the speed reducer 3 side. It is sandwiched between the yoke 10.
The center case 22 is disposed between the front housing 23 that covers the front of the starter 1 and the yoke 10, and covers the outer periphery of the clutch 5 and the speed reducer 3.
The center case 22, the yoke 10, and the end frame 19 are fixed by fastening a plurality of through bolts 24 to the front housing 23.

  The speed reducer 3 is a planetary gear speed reducer that can decelerate on the same axis as the armature shaft 15, and is configured on the side of the armature 13 opposite to the commutator. As shown in FIG. 3, the speed reducer 3 is disposed concentrically with the sun gear 25 provided at the end of the armature shaft 15 protruding from the center plate 21, and the shock absorbing device 4 ( And a plurality of planetary gears 27 meshing with both gears 25, 26, and the revolving motion of the planetary gears 27 is applied to the pinion shaft 6 via the clutch 5. Communicated. The planetary gear 27 is rotatably supported by a planetary pin 27a via a bearing 28 (for example, a needle bearing), and the planetary pin 27a is fixed to a clutch outer 29 described below by press fitting or the like.

  As shown in FIG. 3, the clutch 5 is provided between the speed reducer 3 and the pinion shaft 6, and a clutch outer 29 to which the driving torque of the motor 2 is transmitted via the speed reducer 3 and a bearing 30. An inner tube 31 that is rotatably supported by the center case 22 and a roller 32 that is disposed in a cam chamber formed on the inner periphery of the clutch outer 29 and interrupts torque transmission between the clutch outer 29 and the inner tube 31. Etc. The clutch 5 is configured as a one-way clutch that transmits the driving torque of the motor 2 to the pinion shaft 6 and blocks torque transmission from the pinion shaft 6 to the motor 2 side.

The pinion shaft 6 is disposed coaxially with the armature shaft 15, and one end side is rotatably and slidably supported by the front housing 23 via the bearing 33, and the other end side is inserted into the inner periphery of the inner tube 31. Have been connected by a helical spline.
The pinion gear 7 meshes with the ring gear 34 (see FIG. 2) of the engine when the engine is started, and has a function of transmitting the driving torque of the motor 2 to the ring gear 34. The pinion gear 7 is serrated to the tip of the pinion shaft 6 protruding forward (leftward in FIG. 2) from the bearing 33, and is urged by a pinion spring 35 disposed on the inner periphery of the pinion gear 7. It is positioned by a stopper 36 attached to the tip of the pinion shaft 6.

  The electromagnetic switch 9 includes an electromagnetic coil 37 that is energized from a battery to form an electromagnet, and a plunger 38 that is movable in the axial direction on the inner periphery of the electromagnetic coil 37, and the electromagnet is formed by energizing the electromagnetic coil 37. Then, the plunger 38 is attracted by the electromagnet and moved rightward in FIG. 2 to close the main contact of the motor circuit in conjunction with the movement of the plunger 38. When the energization of the electromagnetic coil 37 is stopped and the attractive force of the electromagnet disappears, the plunger 38 is pushed back by the reaction force of the return spring 39, thereby opening the main contact.

The main contact includes a set of fixed contacts 42 connected to the motor circuit via two external terminals 40 and 41, and a movable contact 43 that moves integrally with the plunger 38 and intermittently connects between the set of fixed contacts 42. The main contact is closed when the pair of fixed contacts 42 are conducted through the movable contact 43, and the main contact is opened by shutting off the conduction between the pair of fixed contacts 42. It becomes a state.
The two external terminals 40 and 41 are a B terminal 40 connected to the in-vehicle battery via a battery cable (not shown) and an M terminal 41 to which a terminal 44 taken out from the motor 2 is connected. The electromagnetic switch 9 is fixed to the resin cover 9a. The terminal 44 is held by a grommet 45 sandwiched between the yoke 10 and the end frame 19, and the end on the anti-M terminal side is connected to the field coil 11.

The shift lever 8 has a lever fulcrum portion 8a that is swingably supported, and a lever end portion on one end side of the lever fulcrum portion 8a is connected to a shift rod 46 provided on the electromagnetic switch 9, so that the lever fulcrum portion is provided. The lever end on the other end side from 8 a is engaged with the pinion shaft 6, and the movement of the plunger 38 is transmitted to the pinion shaft 6.
The shift rod 46 is assembled together with the drive spring 47 to the plunger 38 of the electromagnetic switch 9 and has a function of transmitting the movement of the plunger 38 to the shift lever 8 through the drive spring 47.

Next, the impact absorbing device 4 according to the present invention will be described in detail.
The impact absorbing device 4 has a function of reducing impact torque generated when the pinion gear 7 drives the ring gear 34, for example, and as shown in FIG. 3, a cylindrical case 48, a fixed disc 49, a rotating disc 50, a dish It comprises a spring 51, a nut 52, and the like.
The cylindrical case 48 is fixed to the inner periphery of the center case 22 so as not to rotate. The cylindrical case 48 is provided with an annular bottom plate portion 48a bent from the right end in the figure to the inner diameter side. The inner diameter of the bottom plate portion 48 a has a size that does not interfere with the planetary gear 27 of the speed reducer 3. Further, a female thread portion 48 b is formed on the left inner periphery of the cylindrical case 48 in the figure.

The fixed disk 49 and the rotating disk 50 are each press-molded from a metal plate into a ring shape, and are stacked one by one alternately and disposed inside the cylindrical case 48. However, fixed disks 49 are arranged on both outer sides of the overlapped disks 49 and 50, respectively, and one of the fixed disks 49 is in contact with the bottom plate portion 48 a of the cylindrical case 48.
As shown in FIG. 4, the fixed disk 49 has a plurality of protrusions 49 a that protrude in the outer diameter direction on the outer periphery, and these protrusions 49 a are recessed portions 48 c (see FIG. 4) provided on the inner periphery of the cylindrical case 48. 3) and is supported so as not to rotate. The fixed disk 49 has a ring-shaped inner diameter that is substantially equal to the inner diameter of the bottom plate portion 48 a provided in the cylindrical case 48 and has a size that does not interfere with the planetary gear 27 of the speed reducer 3.

The rotating disk 50 has an outer diameter slightly smaller than the inner peripheral diameter of the cylindrical case 48 and is disposed so as to be rotatable relative to the cylindrical case 48. As shown in FIG. 5, the rotating disk 50 has teeth 50a formed on the entire inner periphery of a ring shape, and the planetary gear 27 of the speed reducer 3 is meshed with the teeth 50a (see FIG. 3). That is, the plurality of rotating disks 50 constitute the internal gear 26 of the speed reducer 3.
The disc spring 51 applies a load to the laminated body in which the fixed disk 49 and the rotating disk 50 are overlapped to generate a frictional force between the fixed disk 49 and the rotating disk 50. In FIG. 3, the disc springs 51 are arranged in two stages via the washer 53, but only one stage may be used. Further, in the case of one stage, the washer 53 can be eliminated.
The nut 52 is coupled to the female thread portion 48b of the cylindrical case 48 and adjusts the initial load with which the disc spring 51 presses the laminated body so that a prescribed sliding torque is obtained between the fixed disk 49 and the rotating disk 50. is doing.

By the way, as shown in FIGS. 4 and 5, a large number of dimples 49b and 50b (concave portions) are formed on both surfaces (friction surfaces) where the fixed disk 49 and the rotating disk 50 come into contact with each other, and grease is used. A lubricant such as is applied.
The dimples 49b and 50b formed on both the disks 49 and 50 have a function of holding the lubricant applied to the surface, and are arranged in the same shape, the same size, and the same pattern. Each of the dimples 49b and 50b is formed by, for example, driving a punch (not shown) having a square cross section into the surface of a metal plate, and has a square outer peripheral shape as shown in FIG. Further, as shown in FIG. 6B, when the punch is driven, the material that has flowed to the outside of the punch rises on the surfaces of the disks 49 and 50, so that convex portions are formed around the dimples 49b and 50b. 49c and 50c are formed.

As shown in FIG. 6A, the dimples 49b and 50b formed on the friction surfaces of the fixed disk 49 and the rotating disk 50 have a square four sides at a predetermined angle α (this embodiment) with respect to the radial direction of the disks 49 and 50. , Α = 45 degrees) and are arranged in a matrix at a constant pitch. However, the dimples 49b of the fixed disk 49 and the dimples 50b of the rotating disk 50 are formed such that the dimple positions of both are shifted by a predetermined amount in the radial direction (vertical direction in the figure) in the entire pattern, as shown in FIG. Yes.
Further, as shown in FIG. 1, when the amount of radial displacement between the dimple 49b of the fixed disk 49 and the dimple 50b of the rotating disk 50 is the offset amount X, and the pitch between the dimples adjacent in the radial direction is Pd. The relationship between the offset amount X and the pitch Pd is expressed by the following equation (1).
X = Pd × (0.1-0.5) (1)

The cross-sectional view shown in FIG. 1 is a BB cross-sectional view shown in FIG. 7B, and the circumferential position of the dimple 49b of the fixed disk 49 and the circumferential position of the dimple 50b of the rotating disk 50 coincide. Shows the state.
Further, the constants 0.1 to 0.5 shown in the above equation (1) indicate that the dimples 49b of the fixed disk 49 and the dimples 50b of the rotating disk 50 face each other (the positions in the circumferential direction of both the dimples 49b and 50b are The projections 49c and 50c formed around the dimples 49b and 50b are set so as not to overlap each other when they coincide.

Next, the operation of the starter 1 will be described.
When the plunger 38 is attracted by energizing the electromagnetic coil 37 of the electromagnetic switch 9 by closing the start switch (not shown), the movement of the plunger 38 is transmitted to the pinion shaft 6 via the shift lever 8. . As a result, the pinion shaft 6 moves in the counter-motor direction (left direction in FIG. 2) while rotating with respect to the inner tube 31 by the action of the helical spline, and after the end surface of the pinion gear 7 comes into contact with the end surface of the ring gear 34 Then, the pinion spring 35 is temporarily stopped while being compressed.

  After that, when the plunger 38 further moves and closes the main contact while accumulating the reaction force in the drive spring 47, power is supplied from the battery to the motor 2 to generate a rotational force in the armature 13, and the armature 13 rotates. After being decelerated by the reduction gear 3, it is transmitted to the pinion shaft 6 through the clutch 5. As a result, the pinion shaft 6 is forcibly rotated, so that the pinion shaft 6 moves forward by the reaction force stored in the drive spring 47 when the pinion gear 7 rotates to a position where it can mesh with the ring gear 34. As a result, the pinion gear 7 meshes with the ring gear 34, and the driving torque of the motor 2 amplified by the speed reducer 3 is transmitted from the pinion gear 7 to the ring gear 34, whereby the engine is cranked.

During the cranking, an impact force is generated when the pinion gear 7 is engaged with the ring gear 34 to drive the ring gear 34. This impact force is transmitted from the pinion gear 7 to the output shaft → inner tube 31 → roller 32 → clutch outer 29 → planet pin 28 → planet gear 27 → internal gear 26. At this time, when the impact force transmitted to the internal gear 26 exceeds the sliding torque of the rotating disk 50, the rotating disk 50 slides (rotates) against the frictional force, thereby allowing the internal gear 26 to rotate. Thus, the impact force is reduced.
After the engine is started, when the start switch is opened, when the energization of the electromagnetic coil 37 is stopped and the attraction force of the electromagnet disappears, the plunger 38 is pushed back by the reaction force of the return spring 39. When the power supply to the motor 2 is stopped, the rotation of the armature 13 is gradually decelerated and stopped.
On the other hand, when the plunger 38 is pushed back, the shift lever 8 swings in the direction opposite to that at the start of the engine, and the pinion shaft 6 moves backward.

(Effect of Example 1)
The shock absorbing device 4 provided in the starter 1 has a large number of dimples 49b and 50b formed on the friction surface of the fixed disk 49 and the friction surface of the rotary disk 50, respectively. It is possible to hold the lubricant applied to the surface for a long time. Further, a large number of dimples 49b formed on the fixed disk 49 and a large number of dimples 50b formed on the rotating disk 50 have their dimple positions shifted by a predetermined amount (offset amount X) in the radial direction in the entire pattern. .

  As a result, when the dimples 49b, 50b of the two disks 49, 50 face each other (when the circumferential positions of the two dimples 49b, 50b match), as shown in FIG. The gap C is formed between the convex portions 49c and 50c formed around 50b, so that the oil film breakage of the lubricant generated by the contact between the convex portions 49c and 50c can be reduced. As a result, the wear resistance of both the disks 49 and 50 is improved, and the life of the shock absorbing device 4 can be extended. In addition, since the fluctuation of the friction coefficient between both the disks 49 and 50 can be suppressed, the sliding torque of the rotating disk 50 can be stabilized.

FIG. 8A is a plan view showing a part of the friction surface of the fixed disk 49, and FIG. 8B is a plan view showing a part of the friction surface of the rotating disk 50.
In the impact absorbing device 4 shown in the second embodiment, as shown in FIG. 8, the pitch P1 between the dimples formed on the fixed disk 49 and the pitch P2 between the dimples formed on the rotating disk 50 are different. It is an example. In addition, the shape and size of the individual dimples 49b and 50b formed on both the disks 49 and 50 are the same, and the arrangement pattern is also the same.
The relationship between the pitch P1 and the pitch P2 is expressed by the following equation (2) or (3).
P1 = P2 × (1.1 to 1.5) (2)
P2 = P1 × (1.1 to 1.5) (3)

According to the above configuration, since the pitch between the dimples of both the disks 49 and 50 is different (P1 ≠ P2), the protrusions 49c and 50c formed around the dimples 49b and 50b of the both disks 49 and 50 have a period. The probability of contact is reduced, and the oil film breakage of the lubricant generated by the contact between the convex portions 49c and 50c can be reduced.
In order to effectively shift the radial position of the dimple 50b of the rotating disk 50 from the radial position of the dimple 49b of the fixed disk 49, 1.1 or more is required, and the rotating disk 50 has an appropriate density. In order to arrange the dimples 50b and the dimples 49b of the fixed disk 49, 1.5 or less is required.
Further, in place of P1 and P2 used in the above equations (2) and (3), the radial pitches Pd1 and Pd2 of the dimples 49b and 50b of both disks 49 and 50 may be used.

FIG. 9A is a plan view showing a part of the friction surface of the fixed disk 49, and FIG. 9B is a plan view showing a part of the friction surface of the rotating disk 50.
In the shock absorbing device 4 shown in the third embodiment, as shown in FIG. 9, a large number of dimples 49b and 50b arranged in the same pattern (matrix) are formed on the friction surfaces of the fixed disk 49 and the rotating disk 50, respectively. In addition, the arrangement pattern of the dimples 49b of the fixed disk 49 and the arrangement pattern of the dimples 50b of the rotating disk 50 are set in different directions.

That is, the arrangement pattern of the dimples 49b of the fixed disk 49 is, for example, a large number of dimples 49b arranged in a direction inclined by 45 degrees with respect to the radial direction of the fixed disk 49. A large number of dimples 50b are arranged in a direction inclined by α (α ≠ 45 degrees) with respect to the radial direction of the rotating disk 50.
According to the above configuration, the probability that the convex portions 49c and 50c formed around the dimples 49b and 50b of the both disks 49 and 50 periodically come into contact with each other decreases. Oil film breakage of the generated lubricant can be reduced.

FIG. 10 is a plan view showing a part of the friction surface of the fixed disk 49 and the rotating disk 50.
A large number of dimples 49b and 50b are respectively formed on the friction surfaces of the fixed disk 49 and the rotating disk 50 shown in the fourth embodiment, and the large number of dimples 49b and 50b are arranged along the circumferential direction as shown in FIG. A plurality of blocks arranged in a row and a plurality of layers arranged in the radial direction are formed. The dimples 49b and 50b of each block are at the same position in the circumferential direction, and the dimples 49b and 50b of each layer are at the same position in the radial direction. That is, the dimples 49b and 50b formed on both the disks 49 and 50 have a constant pitch [radial pitch Pd, average circumferential pitch Pdtanθ ( 0 <θ <90 degrees)].

However, the position of the dimple 50b formed in each block of the rotating disk 50 is a predetermined amount in the radial direction with respect to the position of the dimple 49b formed in each block of the fixed disk 49 (as in the first embodiment). The offset amount X) is shifted (see FIG. 1). Further, the dimples 49b adjacent to each other in the circumferential direction in each block and the dimples 50b are different in position in the radial direction by Pd / 2.
According to the above configuration, the positions of the dimples 50b of the rotating disk 50 are different in the radial direction with respect to the positions of the dimples 49b of the fixed disk 49. Therefore, when the rotating disk 50 rotates, The formed dimple 50b does not pass directly above the dimple 49b formed on the fixed disk 49. As a result, the oil film breakage of the lubricant generated by the contact between the projections 49c and 50c formed around the dimples 49b and 50b can be reduced, so that the wear resistance of both the disks 49 and 50 is improved and the impact is reduced. It is possible to extend the life of the absorber 4.

FIG. 11 is a plan view showing a part of the friction surface of the fixed disk 49 and the rotating disk 50.
In the fifth embodiment, as shown in FIG. 11, both the fixed disk 49 and the rotating disk 50, or the dimples 49b and 50b formed on one of the disks 49 or 50 are arranged at random. is there.
Also in the case of this embodiment, the probability that the convex portions 49c and 50c formed around the dimples 49b and 50b of the both disks 49 and 50 periodically contact each other can be reduced, so that the contact between the convex portions 49c and 50c can be reduced. Oil film breakage of the generated lubricant can be reduced.

(Modification)
In the first to third embodiments, the arrangement pattern of the dimples 49b of the fixed disk 49 and the arrangement pattern of the dimples 50b of the rotating disk 50 are the same, but the arrangement pattern of both the disks 49 and 50 may be changed. . In this case, even if the shapes and sizes of the individual dimples 49b and 50b are the same, the dimples 49b and 50b formed on both the disks 49 and 50 have different arrangement patterns, so that they are formed around the dimples 49b and 50b. The probability that the convex portions 49c and 50c to be periodically contacted with each other is reduced, and the oil film breakage of the lubricant generated by the contact between the convex portions 49c and 50c can be reduced.

Further, the dimples 49b formed on the fixed disk 49 and the dimples 50b formed on the rotating disk 50 may be formed so that the shape or size of the both are different, or both the shape and size are different. good.
In the first embodiment, the shock absorbing device 4 having a multi-plate structure in which the fixed disks 49 and the rotating disks 50 are alternately arranged one by one is described. However, in the present invention, one fixed disk 49 and one rotating disk 50 are provided. The present invention can also be applied to the impact absorbing device 4 having a single-plate structure used one by one.

(Example 1) which is sectional drawing which shows the contact surface of a fixed disk and a rotation disk. It is sectional drawing of a starter. It is an expanded sectional view showing the composition of an impact absorption device. It is a top view of a fixed disk. It is a top view of a rotating disk. It is a top view of the disk which shows arrangement | positioning of a dimple, (b) It is sectional drawing (AA sectional drawing) of a dimple. (A) The top view which shows the state which the dimple position of both discs has shifted | deviated to radial direction, (b) The top view which shows the state in which the dimple position of both discs overlapped with the circumferential direction. (A) The top view which shows a part of friction surface of a fixed disk, (b) The top view which shows a part of friction surface of a rotation disk (Example 2). (A) The top view which shows a part of friction surface of a fixed disk, (b) The top view which shows a part of friction surface of a rotation disk (Example 3). (Example 4) which is a top view which shows a part of fixed disk or rotation disk which formed many dimples for every block. (Example 5) which is a top view which shows a part of fixed disk or rotation disk which arrange | positioned the dimple at random.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Starter 4 Shock absorber 49 Fixed disk 50 Rotating disk 49b Dimple formed on the friction surface of the fixed disk 50b Dimple formed on the friction surface of the rotating disk

Claims (4)

When a load torque exceeding a predetermined torque is applied to the rotating disk, the rotating disk rotates (slides) against the frictional force when the rotating disk has a fixed disk and a rotating disk in contact with each other. In an impact absorbing device that absorbs impact,
A plurality of dimples having the same shape, the same size, and the same pattern are formed on the friction surfaces of the fixed disk and the rotating disk, and the pitch between the dimples formed on the fixed disk is formed. An impact absorbing device , wherein P1 and a pitch P2 between dimples formed on the rotating disk are different . The shock absorber according to claim 1 ,
The relationship between the pitch P1 and the pitch P2 is
P1 = P2 × (1.1 to 1.5) (1)
An impact absorbing device represented by the above formula (1) . The shock absorber according to claim 1 ,
The relationship between the pitch P1 and the pitch P2 is
P2 = P1 × (1.1 to 1.5) (2)
An impact absorbing device represented by the above formula (2) . 4. The shock absorbing device according to claim 1, wherein the shock absorbing device is used in a starter for starting an engine .

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