The invention relates to a load applying device.
A load applying device for applying load to an object such as a parking brake aims to apply a predetermined load to the object. Therefore, it is necessary to check, when the load is applied to the operation object, whether the load is appropriately applied. Although the load applied by the load applying device may be measured by control, a load sensor is used to check whether a desired load is actually applied (For example, Patent document 1).
Patent Document 1: JP 2008-202957 A
However, in a case that a load applying device is provided with a load sensor to check whether the load applying device applies a desired load, it is necessary to firmly connect the load sensor with the side of the drive portion applying the load. Therefore, the connection structure to connect the load sensor with the side of the drive portion becomes complex.
An object of the invention is to provide a load applying device to connect the load sensor with the drive portion side in a simple configuration.
A load applying device according to the invention comprises: a rotatable shaft member having a rotatable shaft member screw portion provided coaxially with respect to a rotation axis of the rotatable shaft member; a drive portion for rotating the rotatable shaft member; a movable shaft member having a one end portion and an other end portion and a movable shaft member screw portion screwed to the rotatable shaft member screw portion; a connecting member to connect the one end portion side of the movable shaft member with an operation object to which load is applied; a load sensor having a housing, a spring member including a free end to be connected to the housing, and a sensor element; and a rotation suppressing portion to suppress rotation of the movable shaft member, wherein the other end portion of the movable shaft member has a pressing portion to press the housing of the load sensor, the movable shaft member is configured to move in an axis direction with driving of the drive portion to apply load to the connecting member and press the housing of the load sensor by the pressing portion, and the sensor element is configured to move with movement of the housing due to pressing of the movable shaft member to detect load by the movable shaft member.
The load applying device according to the invention makes it possible to connect the load sensor with the drive portion side in a simple configuration.
Below, with reference to the drawings, a load applying device according to one embodiment of the invention is described. The embodiment shown below is merely one example, so that the load applying device according to the invention is not limited to the embodiment below.
As shown in
The load applying device 1 has a connecting member 4 to connect a one end portion 22a side (in the embodiment, a one end portion 221a side of the one side movable shaft member 221) of the movable shaft member 22 with an operation object O to which load is applied. The load applying device 1 further has rotation suppressing portions S1, S2 (see
While the operation of the load applying device 1 is to be described below, the load applying device 1 is configured such that the entire length of the shaft member 2 in an axis X direction extends and contracts by driving of the drive portion 3. In the embodiment, as shown in
In the embodiment, the load applying device 1 is an electric parking brake drive device. Specifically, as shown in
In the embodiment, as shown in
The drive portion 3 rotates the rotatable shaft member 21 to apply load to the operation object O, or to release the load applied to the operation object O. In the embodiment, as shown in
In the embodiment, the drive portion 3 has a motor 31 (see
The connecting member 4 connects the one end portion 22a side of the movable shaft member 22 and the operation object O to which load is applied. In other words, the connecting member 4 is provided between the one end portion 22a of the movable shaft member 22 and the operation object O, and the movable shaft member 22 and the operation object O are indirectly connected via the connecting member 4. In the embodiment, the connecting member 4 is directly connected to the one end portion 221a of the one side movable shaft member 221. However, the connecting member 4 may be indirectly connected to the movable shaft member 22. Moreover, in the embodiment, the connecting member 4 is connected, via the cable C, to the operation object O. The connecting member 4 may be directly connected to the operation object O.
As described above, the connecting member 4 moves in the axis X direction by movement of the movable shaft member 22 in the axis X direction. By the connecting member 4 moving in the axis X direction, load is applied to the operation object O. In the embodiment, the connecting member 4 is guided to the guiding portion 61 of the casing 6 and slides in the axis X direction in conjunction with movement of the one side movable shaft member 221 in the axis X direction, and load is applied, via the cable C, to the operation object O.
In the embodiment, the connecting member 4 is formed separately from the shaft member 2 (the one side movable shaft member 221) and the cable C. However, a portion to function as a connecting member may be integrally provided to a one end portion of the shaft member 2 (the one end portion 22a of the movable shaft member 22) or an other end Cb of the cable C. In the embodiment, the load applying device 1 has two shaft members being the one side movable shaft member 221 and the other side movable shaft member 222, and the one end portion 221a of the one side movable shaft member 221 is connected to the connecting member 4. However, the shaft member 2 may be composed of single rotatable shaft member 21 and single movable shaft member 222, for example. In this case, the one end portion 21a of the rotatable shaft member 21 may be rotatably connected to the connecting member 4.
The shaft member 2 has the rotatable shaft member 21 and the movable shaft member 22. By the rotation of the rotatable shaft member 21, the movable shaft member 22 relatively moves in the axis X direction with respect to the rotatable shaft member 21 to apply load to the operation object O. In the embodiment, the movable shaft member 22 has the one side movable shaft member 221 provided on one side in the axis X direction and the other side movable shaft member 222 provided on the other side in the axis X direction. The one side movable shaft member 221 is provided on one side (the connecting member 4 side) in the axis X direction with respect to the rotatable shaft member 21 and is screwed to the one end portion 21a side of the rotatable shaft member 21. The other side movable shaft member 222 is provided on the other side (the load sensor 5 side) in the axis X direction with respect to the rotatable shaft member 21 and is screwed to the other end portion 21b side of the rotatable shaft member 21. While details will be described below, in the embodiment, when the rotatable shaft member 21 rotates, the one side movable shaft member 221 and the other side movable shaft member 222 relatively move in the axis X direction with respect to the rotatable shaft member 21, so that the entire length of the shaft member 2 (in the embodiment, the entire length from the one end portion 22a to the other end portion 22b of the movable shaft member 22) changes to extend and contract the shaft member 2. In this way, the connecting member 4 moves in the axis X direction, and load is applied, via the cable C, to the operation object O when the connecting member 4 moves in the axis X direction, or, in other words, moves to the other side (to the right in
The rotatable shaft member 21 rotates around the axis X by the drive portion 3. The rotatable shaft member 21 is screwed to the movable shaft member 22 to relatively move the moving shaft 22 in the axis X direction with respect to the rotatable shaft member 21 when the rotatable shaft member 21 rotates around the axis X. In the embodiment, the one side movable shaft member 221 is connected to the connecting member 4, and, by moving to the other side in the axis X direction in conjunction with rotation of the rotatable shaft member 21 around the axis X, load is applied to the operation object O. On the other hand, the other side movable shaft member 222 is connected to the load sensor 5, and load applied to the operation object O is detected when the other side movable shaft member 222 moves to the one side in the axis X direction as described below. As described above, the shaft member 2 may be composed of the rotatable shaft member 21 and the other side movable shaft member 222 and does not necessarily have to include the one side movable shaft member 221.
As shown in
In the embodiment, the rotatable shaft member screw portion 211 is a female screw provided on the inner periphery of the rotatable shaft member 21 being formed as a hollow cylindrical body. In the embodiment, the movable shaft member screw portions 221c, 222c are male screws provided on the outer periphery of the movable shaft member 22 to be inserted inside the rotatable shaft member 21. However, as long as the movable shaft member 22 may relatively move in the axis X direction with respect to the rotatable shaft member 21 by rotation of the rotatable shaft member 21, the rotatable shaft member screw portion 211 may be a male screw, while the movable shaft member screw portions 221c, 222c may be female screws.
In the embodiment, the rotatable shaft member screw portion 211 of the rotatable shaft member 21 has a one side rotatable screw portion 211a to be screwed to the one side movable shaft member 221, and an other side rotatable screw portion 211b to be screwed to the other side movable shaft member 222. The one side rotatable screw portion 211a of the rotatable shaft member 21 is screwed to the movable shaft member screw portion 221c of the one side movable shaft member 221. The other side rotatable screw portion 211b of the rotatable shaft member 21 is screwed to the movable shaft member screw portion 222c of the other side movable shaft member 222. In the embodiment, the one side rotatable screw portion 211a and the other side rotatable screw portion 211b are threaded in the reverse direction with respect to each other. In this way, when the rotatable shaft member 21 rotates in one direction, the one side movable shaft member 221 and the other side movable shaft member 222 relatively move so that they approach each other in the axis X direction. Moreover, when the rotatable shaft member 21 rotates in the other direction, the one side movable shaft member 221 and the other side movable shaft member 222 relatively moves away from each other in the axis X direction.
In the embodiment, in between the one side rotatable screw portion 211a on the one end portion 21a side of the rotatable shaft member 21 and the other side rotatable screw portion 211b on the other end portion 21b side in the axis X direction of the rotatable shaft member 21, the rotatable shaft member screw portion 211 has an unthreaded portion 212 in which no screw is formed. In this case, resistance at the time of screwing in the unthreaded portion 212 is reduced when the rotatable shaft member 21 and the movable shaft member 22 are screwed to each other, making relative movement between the rotatable shaft member 21 and the movable shaft member 22 smooth. The rotatable shaft member screw portion 211 may be formed over the entirety of the rotatable shaft member 21 in the axis X direction.
Rotation of the movable shaft member 22 around the axis X is suppressed by the rotation suppressing portions S1, S2. The rotation suppressing portions S1, S2 suppress the movable shaft member 22 co-rotating with the rotatable shaft member 21 at the time of rotation of the rotatable shaft member 21 around the axis X by suppressing rotation of the movable shaft member 22 around the axis X. In this way, the movable shaft member 22 can relatively move in the axis X direction with respect to the rotatable shaft member 21 when the rotatable shaft member 21 rotates around the axis X by screwing between the rotatable shaft member 21 and the movable shaft member 22. The structure or position of the rotation suppressing portions S1, S2 is not particularly limited as long as the rotation suppressing portions S1, S2 can suppress rotation of the movable shaft member 22 around the axis X. In the embodiment, the rotation suppressing portion S1 is configured to engage with the other end portion 222b of the other side movable shaft member 222 around the axis X. In the embodiment, the rotation suppressing portion S1 is provided in the load sensor 5 to be described below and is formed as a housing recess to engage, in the direction around the axis X, with the other end portion 222b of the other side movable shaft member 222 being formed in a polygon shape as in a head portion of a bolt, for example. Moreover, the rotation suppressing portion S2 is configured to engage with the one end portion 221a of the one side movable shaft member 221 in the direction around the axis X. In the embodiment, the rotation suppressing portion S2 is provided in the connecting member 4 and is formed as a housing recess to engage, in the direction around axis X, with the one end portion 221a of the one side movable shaft member 221 being formed in a polygon shape, for example.
In the embodiment, the rotatable shaft member 21 is configured to rotate around the axis X, and move in the axis X direction with respect to the drive portion 3. Specifically, the fitting member 32 and the outer periphery of the rotatable shaft member 21 are spline-fitted, for example, as described above so that the rotatable shaft member 21 may be rotated around the axis X by the drive portion 3 and may move in the axis X direction. In this way, the rotatable shaft member 21 moves in the axis X direction with respect to the drive portion 3 or the casing 6.
The load sensor 5 detects load applied to the operation object O. Specifically, the load sensor 5 detects that load being greater than or equal to a predetermined amount is applied to the operation object O. The load sensor 5 has a housing 51, a spring member 52 including a free end 52a to be connected to the housing 51, and a sensor element 53. While details will be described below, the other end portion 22b of the movable shaft member 22 has a pressing portion P to press the housing 51 of the load sensor 5, the movable shaft member 22 is configured to move in the axis X direction with driving of the drive portion 3 to apply load to the connecting member 4 and press the housing 51 of the load sensor 5 by the pressing portion P. The sensor element 53 is configured to move with movement of the housing 51 due to pressing of the movable shaft member 22 to detect load by the movable shaft member 22.
The sensor element 53 is configured to detect load applied to the operation object O according to the position of the sensor element 53 in the axis X direction being changed. The sensor element 53 is not particularly limited as long as the sensor element 53 may detect load according to the position of the sensor element 53 in the axis X direction being changed. In the embodiment, the sensor element 53 is a constituting element of a magnetic sensor to detect a change in the magnetic field due to a change in the position relationship between a magnet and a Hall IC. Specifically, in the embodiment, the sensor element 53 is a magnet being fixed, via a mounting member 54, to the housing 51. A Hall IC (a second sensor element) 55 being arranged to not relatively move with respect to the sensor element 53 is provided at the position opposing the sensor element 53. Alternatively, the sensor element 53 may be the Hall IC and the magnet may be provided at the position opposing the sensor element 53. The magnet 53 being one portion of the sensor element is preferably guided to move, in a predetermined position relationship, with respect to the Hall IC 55 being another portion of the sensor element. The magnet 53 may be guided in the state of being supported by a supporting portion to slide with the mounting member 54 such that the mounting member 54 does not oscillate when a movable portion 512 moves. The supporting portion may be provided to not relatively move with the casing 6, and is provided in a wall portion between the sensor housing portion 63 and a drive portion housing portion 64 in the embodiment. This supporting portion can suppress sliding of the mounting member 54 by having a groove to slide with the mounting member 54, for example. When the end edge of the mounting member 54 in the width direction slides inside the groove, the mounting member 54 is supported by the supporting portion, so that oscillation in the upward/ downward direction shown in drawings is suppressed.
The housing 51 houses the spring member 52 inside the housing 51. Inside the housing 51, the spring member 52 is arranged such that a biasing force is applied in the axis X direction. The spring member 52 is not particularly limited as long as the spring member 52 applies the biasing force in the axis X direction. In the embodiment, the spring member 52 is a coil spring, and is arranged such that the axis center of the spring member 52 is coaxial with the axis center of the movable shaft member 22.
In the embodiment, the housing 51 has a portion to move in conjunction with extension and contraction of the spring member 52 housed inside the housing 51. Specifically, in the embodiment, the housing 51 has a base portion 511 provided on one side of the housing 51 in the axis X direction (on one end portion 222a side of the other side movable shaft member 222) and a movable portion 512 provided on the other side of the housing 51 in the axis X direction and moved with respect to the base portion 511.
In the embodiment, the base portion 511 is formed in a shape of a plate extending perpendicularly to the axis X. The movable portion 512 comprises a wall portion 512a extending in the perpendicular direction with respect to the axis X and a covering portion 512b to cover the outer periphery of the spring member 52 externally in the diameter direction, the covering portion 512b extending toward the base portion 511 in the axis X direction from the wall portion 512a. However, the overall shape of the housing 51 or the shape of the base portion 511 and the movable portion 512 is not particularly limited.
In the embodiment, the base portion 511 is fixed to the casing 6 and an end portion on one side 52b of the spring member 52 is fixed to the base portion 511. The movable portion 512 is movable in the axis X direction with respect to the base portion 511. A free end 52a, which is an end portion on the other side of the spring member 52 and changes the position in the axis X direction, is attached to the wall portion 512a of the movable portion 512. In the embodiment, the spring member 52 positions the sensor element 53 at an initial position by biasing the movable portion 512 of the housing 51 to the other side in the axis X direction. More specifically, as shown in
In the embodiment, as shown in
When load is applied to the connecting portion 4 by the movable shaft member 22 moving in the axis X direction with driving of the drive portion 3, the pressing portion P presses the housing 51 of the load sensor 5 and moves the housing 51 to the one side in the axis X direction. In the embodiment, when the pressing portion P presses the housing 51, the movable shaft member 22 (the other side movable shaft member 222) moves to the one side in the axis X direction. Moreover, in the embodiment, load to the connecting portion 4 is indirectly applied via the rotatable shaft member 21 and the one side movable shaft member 221 from the other side movable shaft member 222, and load applied to the connecting member 4 is applied to the operation object O. For example, there can be a case that load applied to the connecting member 4 and the operation object O exceeds a predetermined load, such as when the operation object O, such as a brake mechanism, is operated to a degree sufficient to apply a predetermined braking force, for example. In such a case, the movable shaft member 22 (the other side movable shaft member 222) is configured to move in the axis X direction against the biasing force of the spring member 52 by the pressing portion P pressing the housing 51.
In the embodiment, the other end portion 22b of the movable shaft member 22 has a flange portion protruding externally in the diameter direction with respect to a shaft portion having the movable shaft member screw portion 222c of the movable shaft member 22. The pressing portion P is a surface, which faces the wall portion 512a of the movable portion 512, of the flange portion. However, the structure of the pressing portion P is not particularly limited as long as the pressing portion P can press the housing 51 of the load sensor 5 in the axis X direction.
As described above, the movable shaft member 22 moves in the axis X direction and applies load to the connecting member 4, and the pressing portion P presses the housing 51 of the load sensor 5. Moreover, in such a case, the housing 51 moves in the axis X direction to move the sensor element 53 with pressing of the housing 51 by the pressing portion P, and load by the movable shaft member 22 is detected. In this way, in the embodiment, it suffices that the movable shaft member 22 is connected to the housing 51 of the load sensor 5 such that the pressing portion P can press the housing 51. Therefore, a complicated mounting structure between the movable shaft member 22 and the housing 51 or between the housing 51 and the sensor element 53 is not necessary. Therefore, it is possible to make a connection between the load sensor 5 and the movable shaft member 22 a simple configuration.
In the embodiment, the movable shaft member 22 extends from the opening portion on the one side OP1 to the opening portion on the other side OP2 to pass through the housing 51, and the pressing portion P is connected to the housing on the other side. In this way, the movable shaft member 22 and the hosing 51 are arranged so that they overlap in the axis X direction. Therefore, it is possible to decrease the length of the load applying device 1 in the axis X direction. The load sensor 5 is configured that the housing 51 moves toward the one side against the biasing force of the spring member 52 with the pressing portion P pressing the housing 51 by movement of the movable shaft member 22 (the other side movable shaft member 222 in the embodiment) toward the one side. Moreover, the housing 51 moves toward the other side with pressing of the pressing portion P being released by movement of the movable shaft member 22 (the other side movable shaft member 222 in the embodiment) toward the other side. In this way, when pressing by the pressing portion P is released, the housing 51 can return to the original position by the biasing force of the spring member 52. In the embodiment, the pressing portion P is configured to engage with the external surface (a surface on the other side in the axis X direction) of the wall portion 512a of the movable portion 512 such that the pressing portion P presses the movable portion 512 of the housing 51 to the one side in the axis X direction. In this way, the movable shaft member 22 moving in the axis X direction presses the housing 51 directly by the pressing portion P, the housing 51 itself moves in the axis X direction, and the sensor element 53 also moves in the axis X direction in conjunction therewith.
Next, using example in which the load applying device 1 is applied to the parking brake device with reference to
In
Since rotation of the one side movable shaft member 221 around the axis X is suppressed by the rotation suppressing portion S2 provided in the connecting member 4, the one side movable shaft member 221 almost does not rotate around the axis X. Then, the one side rotatable screw portion 211 of the rotatable shaft member 21 is screwed to the movable shaft member screw portion 221c of the one side movable shaft member 221. The one side movable shaft member 221 moves to the other side in the axis X direction with respect to the rotatable shaft member 21 until a predetermined load is applied to the brake mechanism O connected to the connecting member 4 via the cable C.
As mentioned above, when the drive portion 3 is continuously driven from the state in
In the embodiment, the opening portion OP1 of the housing 51 of the load sensor 5 has a size such that the rotatable shaft member 21 is insertable into the opening portion OP1 when the rotatable shaft member 21 moves in a direction in which the rotatable shaft member 21 approaches to the pressing portion P of the movable shaft member 22. In this case, when the rotatable shaft member 21 moves toward the other side in the axis X direction, the other end portion 21b of the rotatable shaft member 21 can be inserted inside of the housing 51 from the opening portion OP1 of the housing 51 of the load sensor 5 as shown in
When the rotatable shaft member 21, the one side movable shaft member 221, and the other side movable shaft member 222 move from the state shown in
Specifically, while the rotatable shaft member 21 tries to rotate further by driving of the driving portion 3 in the state in which brake is applied in the state in
1 LOAD APPLYING DEVICE (PARKING BRAKE DEVICE)
2 SHAFT MEMBER
21 ROTATABLE SHAFT MEMBER
21
a ONE END PORTION OF ROTATABLE SHAFT MEMBER
21
b OTHER END PORTION OF ROTATABLE SHAFT MEMBER
211 ROTATABLE SHAFT MEMBER SCREW PORTION
211
a ONE SIDE ROTATABLE SCREW PORTION
211
b OTHER SIDE ROTATABLE SCREW PORTION
212 UNTHREADED PORTION
22 MOVABLE SHAFT MEMBER
221 ONE SIDE MOVABLE SHAFT MEMBER
221
a ONE END PORTION OF ONE SIDE MOVABLE SHAFT MEMBER
221
b OTHER END PORTION OF ONE SIDE MOVABLE SHAFT MEMBER
221
c MOVABLE SHAFT MEMBER SCREW PORTION
222 OTHER SIDE MOVABLE SHAFT MEMBER
222
a ONE END PORTION OF OTHER SIDE MOVABLE SHAFT MEMBER
222
b OTHER END PORTION OF OTHER SIDE MOVABLE SHAFT MEMBER
222
c MOVABLE SHAFT MEMBER SCREW PORTION
3 DRIVE PORTION
31 MOTOR
32 FITTING MEMBER
33 DECELERATION MECHANISM
34 DRIVE PORTION CASING
4 CONNECTING MEMBER
5 LOAD SENSOR
51 HOUSING
511 BASE PORTION
512 MOVABLE PORTION
512
a WALL PORTION
512
b COVERING PORTION
52 SPRING MEMBER
52
a FREE END OF SPRING MEMBER
52
b END PORTION ON ONE SIDE OF SPRING MEMBER
53 SENSOR ELEMENT
54 MOUNTING MEMBER
55 HALL IC (SECOND SENSOR ELEMENT)
6 CASING
61 GUIDING PORTION
62 LEADING-OUT PORTION
63 SENSOR HOUSING PORTION
64 DRIVE PORTION HOUSING PORTION
65 POSITIONING PORTION
B BEARING
C CABLE
Ca ONE END OF CABLE
Cb OTHER END OF CABLE
O OPERATION OBJECT (BRAKE MECHANISM)
OP1, OP2 OPENING PORTION
P PRESSING PORTION
S1, S2 ROTATION SUPPRESSING PORTION
X AXIS
Number | Date | Country | Kind |
---|---|---|---|
2018-201912 | Oct 2018 | JP | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2019/041882 | 10/25/2019 | WO | 00 |