Work tool with vibration dampers

Abstract

It is an object of the invention to provide a more rational vibration reducing technique for a work tool. A representative work tool 100 has an outer housing 102, an inner housing 104, a brushless motor 115, a spindle 124 having a rotation axis extending in parallel to a rotation output shaft of the brushless motor 115 and configured to be rotated on the rotation axis within a prescribed angular range to drive a tool accessory 145, a front elastic member 110a disposed between a front inner housing region 104a and a front outer housing region 102a, and a rear elastic member 110c disposed between at least one of an intermediate inner housing region 104b and a rear inner housing region 104c and at least one of an intermediate outer housing region 102b and a rear outer housing region 102c.

Claims

1. A work tool configured to perform an operation on a workpiece by driving a tool accessory, the work tool comprising: an elongated housing, a brushless motor having a rotational output shaft, a cooling fan configured to be driven by the output shaft, a controller configured to control driving of the brushless motor, and a spindle having a rotation axis extending in parallel to the output shaft of the brushless motor and configured to be rotated on the rotation axis within a prescribed angular range via the brushless motor to drive the tool accessory, wherein: in a longitudinal direction which is defined as an extending direction of the elongate housing, the housing has a front housing region that defines a front region of the housing, a rear housing region that defines a rear region of the housing, and an intermediate housing region that defines an intermediate part between the front housing region and the rear housing region, an entirety of at least the brushless motor, the output shaft and the cooling fan is in the front housing region, an entirety of the controller is in the rear housing region, the intermediate housing region has a smaller cross sectional area perpendicular to the longitudinal direction than the front housing region and the rear housing region, and the elongated housing, the cooling fan, the controller and the motor are configured and arranged such that rotation of the cooling fan draws cooling air from the atmosphere into the elongated housing at the rear housing region to cool the controller, the cooling air is then drawn through the intermediate housing region to the front housing region to cool the brushless motor.

2. The work tool as defined in claim 1, further comprising: an outer housing, an inner housing defined by the elongated housing, the inner housing being housed within the outer housing, and an elastic member configured to elastically connect the outer housing and the inner housing to prevent vibration caused in the inner housing from being transmitted to the outer housing.

3. The work tool as defined in claim 2, wherein: the rear housing region includes an air inlet, the front housing region includes an air outlet and an air passage is formed between the intermediate housing region and the outer housing, and the controller and the brushless motor are in an air flow path extending from the air inlet to the air outlet via the air passage.

4. The work tool as defined in claim 1, wherein: the rear housing region includes an air inlet, the front housing region includes an air outlet and the intermediate housing region includes an air passage, and the controller and the brushless motor are in an air flow path extending from the air inlet to the air outlet via the air passage.

5. The work tool as defined in claim 4, wherein the controller is immediately downstream of the air flow inlet.

6. The work tool as defined in claim 4, further comprising a connecting part for electrically connecting the controller and the brushless motor, wherein the connecting part is at least partly in the air passage.

7. The work tool as defined in claim 1, wherein the elongated housing, the cooling fan, the controller and the motor are configured and arranged such that the cooling air directly cools the controller and the motor.

8. A work tool configured to perform an operation on a workpiece by driving a tool accessory, the work tool comprising: an elongated housing, a brushless motor having a rotational output shaft, a cooling fan configured to be driven by the output shaft, a controller configured to control driving of the brushless motor, and a spindle having a rotation axis and being configured to be rotated on the rotation axis within a prescribed angular range via the brushless motor to drive the tool accessory, wherein: the housing includes an outer housing, an inner housing and an elastic member, wherein the inner housing is housed within the outer housing and the elastic member is configured to elastically connect the outer housing and the inner housing to prevent vibration caused in the inner housing from being transmitted to the outer housing, in a longitudinal direction which is defined as an extending direction of the elongate housing, the inner housing has a front inner housing region that defines a front region of the inner housing, a rear inner housing region that defines a rear region of the inner housing, and an intermediate inner housing region that defines an intermediate part between the front inner housing region and the rear inner housing region, an entirety of the controller is in the rear inner housing region, the brushless motor is in front of the controller in the longitudinal direction, the intermediate inner housing region is longer than the front inner housing region and the rear inner housing region along the longitudinal direction, and the elongated housing, the cooling fan, the controller and the motor are configured and arranged such that rotation of the cooling fan draws cooling air from the atmosphere into the elongated housing at the rear housing region to cool the controller, the cooling air is then drawn through the intermediate housing region to the front housing region to cool the brushless motor.

9. The work tool as defined in claim 8, wherein: the rear inner housing region includes an air inlet, the front inner housing region includes an air outlet and the intermediate inner housing region includes an air passage, and the controller and the brushless motor are in an air flow path extending from the air inlet to the air outlet via the air passage.

10. The work tool as defined in claim 8, wherein the intermediate housing region has a smaller cross sectional area perpendicular to the longitudinal direction than the front housing region and the rear housing region.

11. The work tool as defined in claim 8, wherein the elongated housing, the cooling fan, the controller and the motor are configured and arranged such that the cooling air directly cools the controller and the motor.

12. A work tool configured to perform an operation on a workpiece by driving a tool accessory, the work tool comprising: an elongated housing, a brushless motor having a rotational output shaft, a controller configured to control driving of the brushless motor, and a spindle having a rotation axis extending in parallel to the output shaft of the brushless motor and configured to be rotated on the rotation axis within a prescribed angular range via the brushless motor to drive the tool accessory, wherein: in a longitudinal direction which is defined as an extending direction of the elongate housing, the housing has a front housing region that defines a front region of the housing, a rear housing region that defines a rear region of the housing, and an intermediate housing region that defines an intermediate part between the front housing region and the rear housing region, the rear housing region includes an air inlet, the front housing region includes an air outlet and the intermediate housing region includes an air passage, an entirety of at least the brushless motor, including the output shaft, is in the front housing region, an entirety of the controller is in the rear inner housing region, the controller and the brushless motor are in an air flow path extending from the air inlet to the air outlet via the air passage, the intermediate housing region has a smaller cross sectional area perpendicular to the longitudinal direction than the front housing region and the rear housing region, and the elongated housing, the cooling fan, the controller and the motor are configured and arranged such that rotation of the cooling fan draws cooling air from the atmosphere into the elongated housing at the rear housing region to cool the controller, the cooling air is then drawn through the intermediate housing region to the front housing region to cool the brushless motor.

13. The work tool as defined in claim 12, further comprising: an outer housing, an inner housing defined by the elongated housing, the inner housing being housed within the outer housing, and an elastic member configured to elastically connect the outer housing and the inner housing to prevent vibration caused in the inner housing from being transmitted to the outer housing.

14. The work tool as defined in claim 12, wherein the controller is immediately downstream of the air inlet.

15. The work tool as defined in claim 12, further comprising a connecting part for electrically connecting the controller and the brushless motor, wherein the connecting part is at least partly in the air passage.

16. The work tool as defines in claim 12, wherein the elongated housing, the cooling fan, the controller and the motor are configured and arranged such that the cooling air directly cools the controller and the motor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a sectional view showing an oscillating tool according to a first embodiment of the present invention.

(2) FIG. 2 is sectional view showing the structure of a body housing.

(3) FIG. 3 is a perspective view showing the structures of an inner housing and an intervening member.

(4) FIG. 4 is a perspective view showing the structures of the inner housing and the intervening member.

(5) FIG. 5 is a sectional view showing the structures of an outer housing and the intervening member.

(6) FIG. 6 is a sectional view showing the structure of a front elastic member.

(7) FIG. 7 is a sectional view showing the structure of the inner housing and a driving mechanism housing.

(8) FIG. 8 is a sectional view showing the structure of an upper rear elastic member.

(9) FIG. 9 is a sectional view showing the structures of upper and lower rear elastic members.

(10) FIG. 10 is a sectional view showing the structure of the lower rear elastic member.

(11) FIG. 11 is a sectional view showing the structure of the driving mechanism.

(12) FIG. 12 is a sectional view showing the structure of a driven arm.

(13) FIG. 13 is a sectional view showing the structure of a lock operation mechanism.

(14) FIG. 14 is a sectional view showing an oscillating tool according to a second embodiment of the present invention.

(15) FIG. 15 is a sectional view showing the structure of the body housing.

(16) FIG. 16 is a perspective view showing the structures of the inner housing and the intervening member.

(17) FIG. 17 is a sectional view showing the structures of an intermediate elastic member and the rear elastic members.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

(18) Representative embodiments of a work tool according to the present invention are now described with reference to FIGS. 1 to 17. FIGS. 1 to 13 show a work tool according to a first embodiment, and FIGS. 14 to 17 show a work tool according to a second embodiment.

(19) Parts and mechanisms of the work tool in the second embodiment which are substantially identical or similar to those in the first embodiment are given like designations and numerals as in the first embodiment and will not be further elaborated in the second embodiment.

First Embodiment

(20) The first embodiment of the present invention is now described with reference to FIGS. 1 to 13. In this embodiment, an electric oscillating tool 100 is described as a representative example of the work tool according to the present invention. The oscillating tool 100 is capable of selectively using plural kinds of tool accessories such as a blade and a polishing pad and performing an operation such as a cutting operation and a polishing operation corresponding to the kind of the selected tool accessory on a workpiece by oscillating the tool accessory attached to the oscillating tool 100 as shown in FIG. 1. In FIG. 1, a blade 145 is attached as a representative example of the tool accessory. The blade 145 is an example embodiment that corresponds to the “tool accessory” according to the present invention.

(21) (Body Housing)

(22) The oscillating tool 100 has a body housing 101 as shown in FIG. 1. The body housing 101 mainly includes an outer housing 102 and an inner housing 104 which is housed in the outer housing 102. The outer housing 102 and the inner housing 104 are example embodiments that correspond to the “outer housing” and the “inner housing”, respectively, according to the present invention.

(23) As shown in FIG. 1, the body housing 101 has an elongate form extending in a direction crossing a rotation axis of a brushless motor 115. In this embodiment, the longitudinally extending direction of the body housing 101 is defined as a longitudinal direction, and in the longitudinal direction, one side (left side as viewed in FIG. 1) on which the blade 145 is attached and the other side (right side as viewed in FIG. 1) are respectively defined as a front side and a rear side of the oscillating tool 100. An extending direction of a rotation axis of a spindle 124 described below is defined as a vertical direction, and in the vertical direction, one side (upper side as viewed in FIG. 1) on which a lock operation mechanism 150 described below is mounted and the other side (lower side as viewed in FIG. 1) on which the blade 145 is mounted are respectively defined as an upper side and a lower side of the oscillating tool 100. Further, a direction (direction of a normal to a paper plane of FIG. 1) crossing both the longitudinal direction and the vertical direction is defined as a transverse direction of the oscillating tool 100. The transverse direction corresponds to a vertical direction in FIG. 2 which is a sectional view taken along line I-I in FIG. 1 and to a horizontal direction in FIG. 6 which is a sectional view taken along line in FIG. 1. These definitions of the directions are also appropriately applied in the following descriptions relating to the other drawings and structures.

(24) As shown in FIG. 1, the body housing 101 includes a front body housing region 101a, a rear body housing region 101c arranged on a side opposite to the front body housing region 101a, and an intermediate body housing region 101b arranged between the front body housing region 101a and the rear body housing region 101c.

(25) As shown in FIG. 1, the outer housing 102 includes a front outer housing region 102a, a rear outer housing region 102c arranged on a side opposite to the front outer housing region 102a, and an intermediate outer housing region 102b arranged between the front outer housing region 102a and the rear outer housing region 102c. The intermediate outer housing region 102b forms a grip region to be held by a user. The front outer housing region 102a, the rear outer housing region 102c and the intermediate outer housing region 102b are example embodiments that correspond to the “front outer housing region”, the “rear outer housing region” and the “intermediate outer housing region”, respectively, according to the present invention.

(26) As shown in FIG. 1, the inner housing 104 includes a front inner housing region 104a arranged in the front outer housing region 102a, an intermediate inner housing region 104b arranged in the intermediate outer housing region 104b, and a rear inner housing region 104c arranged in the rear outer housing region 102c. The front inner housing region 104a, the intermediate inner housing region 104b and the rear inner housing region 104c are example embodiments that correspond to the “front inner housing region”, the “intermediate inner housing region” and the “rear inner housing region”, respectively, according to the present invention.

(27) FIG. 2 is a sectional view taken along line I-I in FIG. 1. As shown in FIG. 2, the intermediate outer housing region 102b has a thin part 107 having a smaller width than the front and rear outer housing regions 102a, 102c in the transverse direction.

(28) In the oscillating tool 100, as described below, the brushless motor 115 is housed in the front inner housing region 104a, and a controller 180 is housed in the rear inner housing region 104c. Thus, such parts having a relatively large width in the transverse direction are respectively arranged in the front inner housing region 104a and the rear inner housing region 104c, so that the thin part 107 is formed in the intermediate outer housing region 102b. The thin part 107 is dimensioned to fit well to a hand of a user who uses the intermediate outer housing region 102b as a grip. The thin part 107 is an example embodiment that corresponds to the “thin part” according to the present invention.

(29) As shown in FIG. 1, a slide switch 108 which is operated by a user is arranged on the thin part 107. The slide switch 108 and a battery mounting part 109 are electrically connected to the controller 180. Thus, the brushless motor 115 is turned on and off by operating the slide switch 108. The controller 180 is formed by arranging a switching element for controlling a plurality of coils of the brushless motor 115, a central processing unit (CPU) and a capacitor on a substrate. The controller 180 controls driving of the brushless motor 115 based on operation of the slide switch 108. The brushless motor 115 is an example embodiment that corresponds to the “brushless motor” according to the present invention.

(30) FIGS. 2 to 6 respectively show part of the structures relating to the body housing 101. FIGS. 3 and 4 are perspective views showing the structures of the inner housing 104 and an intervening member 103. FIG. 5 is a sectional view taken along line in FIG. 2, and FIG. 6 is a sectional view taken along line in FIG. 1.

(31) As shown in FIGS. 1, 5 and 6, the outer housing 102 mainly includes a first outer housing 102A arranged on the upper side and a second outer housing 102B arranged on the lower side. The first outer housing 102A and the second outer housing 102B are formed of synthetic resin.

(32) The intervening member 103 which is integrally connected to the outer housing 102 is shown in FIGS. 2 to 6. Particularly, the overall structure of the intervening member 103 is shown in FIGS. 3 and 4. The intervening member 103 is formed of synthetic resin.

(33) As shown in FIGS. 2, 5 and 6, two such intervening members 103 are provided and spaced apart from each other in the transverse direction. The intervening members 103 are integrally connected to the first and second outer housings 102A, 102B by fastening members 103d as shown in FIG. 5. The fastening members 103d are screws. As shown in FIGS. 3 and 4, each of the intervening members 103 has a front intervening member region 103a and a rear intervening member region 103c which extend in the vertical direction, and an intermediate intervening member region 103b extending between the front and rear intervening member regions 103a, 103c. As shown in FIG. 6, the front intervening member region 103a has a plurality of projections 103a1 protruding inward.

(34) As shown in FIGS. 3 and 4, the inner housing 104 is formed by integrally connecting a driving mechanism housing 105, a first inner housing 104A, a second inner housing 104B, a third inner housing 104C and a fourth inner housing 104D. The driving mechanism housing 105 is formed of metal, and the first to fourth inner housings 104A, 104B, 104C, 104D are formed of synthetic resin. As shown in FIG. 1, the driving mechanism housing 105 houses a driving mechanism 120 which drives the blade 145 by the output of the brushless motor 115.

(35) FIG. 7 is a sectional view taken along line IV-IV in FIG. 2. As shown in FIG. 7, the first inner housing 104A and the second inner housing 104B house the brushless motor 115 and are integrally connected to the driving mechanism housing 105 by fastening members 104d. The fastening members 104d are screws. The front inner housing region 104a mainly includes the driving mechanism housing 105, the first inner housing 104A and the second inner housing 104B.

(36) The intermediate inner housing region 104b and the rear inner housing region 104c are hollow as shown in FIG. 1 and mainly include the third inner housing 104C and the fourth inner housing 104D as shown in FIGS. 2 to 4. The third inner housing 104C and the fourth inner housing 104D are arranged adjacent to each other in the transverse direction and integrally connected by fastening members 104f or screws. The third inner housing 104C and the driving mechanism housing 105 are integrally connected by a fastening member 104e shown in FIGS. 1 and 7. The fastening member 104e is a screw. Further, as shown in FIG. 1, a rear end of the second inner housing 104B and front ends of the third and fourth inner housings 104C, 104D are held in contact with each other. With this structure, the driving mechanism housing 105 and the first to fourth inner housings 104A, 104B, 104C, 104D are integrated together.

(37) As shown in FIGS. 1 and 2, an enlarged diameter region is formed in rear regions of the third and fourth inner housings 104C, 104D. The enlarged diameter region forms the rear inner housing region 104c. In the rear inner housing region 104c, the controller 180 is disposed and the battery mounting part 109 for mounting a battery 190 is formed. The battery 190 and the battery mounting part 109 are example embodiments that correspond to the “battery” and the “battery mounting part”, respectively, according to the present invention. The battery mounting part 109 has a power receiving terminal which is electrically connected to a power feeding terminal of the battery 190. The battery mounting part 109 is configured such that the battery 190 can be removably mounted by sliding the battery 190 in the vertical direction. Further, as shown in FIG. 1, the controller 180 is arranged to extend in the sliding direction (the vertical direction) in which the battery 190 is slid to be mounted to the battery mounting part 109. With this structure, a rear body housing region 101c can be shortened in the longitudinal direction.

(38) As shown in FIGS. 2 to 4, inlets 104c1 are formed in the rear inner housing region 104c. The inlets 104c1 are formed in both the third and fourth inner housings 104C, 104D. The controller 180 is arranged immediately downstream of the inlets 104c1. As shown in FIGS. 3 and 4, outlets 104a1 are formed in the second inner housing 104B. An internal space (space part) of the intermediate inner housing region 104b forms an air passage 119 which provides communication between the inlets 104c1 and the outlets 104a1. When a cooling fan 118 (see FIG. 1) mounted on an output shaft 115a of the brushless motor 115 is rotationally driven, outside air is sucked in from the inlets 104c1 and discharged to the outside from the outlets 104a1 via the air passage 119. By this air flow, the controller 180 and the brushless motor 115 are efficiently cooled. The inlet 104c1, the outlet 104a1, the cooling fan 118 and the air passage 119 are example embodiments that correspond to the “inlet”, the “outlet”, the “cooling fan” and the “air passage”, respectively, according to the present invention.

(39) Further, as shown in FIG. 1, a gap is formed between the rear outer housing region 102c and the rear inner housing region 104c and forms a body inlet 101d. With this structure, air which is caused to flow by rotational driving of the cooling fan 118 is led from the body inlet 101d to the inlets 104c1.

(40) Further, a connecting part (not shown) for electrically connecting the brushless motor 115 and the controller 180 is provided in the air passage 119. The connecting part includes a feeding cable and a signal transmitting cable. The internal space of the body housing 101 can be efficiently used by arranging the connecting part in the air passage 119. The connecting part is an example embodiment that corresponds to the “connecting part” according to the present invention.

(41) (Elastic Members)

(42) The outer housing 102 and the inner housing 104 are connected by elastic members. This structure prevents vibration of the inner housing 104 from being transmitted to the outer housing 102. The elastic members include a front elastic member 110a, an intermediate elastic member 110b and a rear elastic member 110c.

(43) As shown in FIG. 6, four front elastic members 110a are arranged between the projections 103a1 of the front intervening member region 103a and the driving mechanism housing 105. The four front elastic members 110a form pair groups of vertically spaced members and pair groups of transversely spaced members. As described above, the driving mechanism housing 105 forms the inner housing 104 and the intervening member 103 is integrally connected to the outer housing 102. Therefore, the front outer housing region 102a and the front inner housing region 104a are connected via the front elastic members 110a. The front elastic member 110a is an example embodiment that corresponds to the “front elastic member” according to the present invention. The front elastic members 110a are rubber elastic elements and are arranged to cover the respective projections 103a1. The driving mechanism housing 105 has recesses in which the projections 103a1 covered by the front elastic members 110a are fitted. With this structure, the front elastic members 110a are disposed between the front outer housing region 102a and the front inner housing region 104a in the longitudinal, vertical and transverse directions. Therefore, transmission of vibration from the front inner housing region 104a to the front outer housing region 102a is effectively prevented or reduced in all directions.

(44) As shown in FIGS. 3, 4, 8 and 9, four rear elastic members 110c are disposed between the rear inner housing region 104c and the rear outer housing region 102c. FIG. 8 is a sectional view taken along line V-V in FIG. 1, and FIG. 9 is a sectional view taken along line VI-VI in FIG. 1. The four rear elastic members 110c form pair groups of vertically spaced members and pair groups of transversely spaced members. The rear elastic member 110c is an example embodiment that corresponds to the “rear elastic member” according to the present invention. The rear elastic members 110c are rubber elastic elements.

(45) As shown in FIGS. 3, 8 and 9, the upper rear elastic member 110c in each pair group of the vertically spaced members is disposed in a space between the rear inner housing region 104c and the rear outer housing region 102c. This space is partly defined by a projection 102c1 formed on the rear outer housing region 102c. The upper rear elastic member 110c is configured to extend in the longitudinal, vertical and transverse directions.

(46) Further, as shown in FIGS. 4, 9 and 10, the lower rear elastic member 110c in each pair group of the vertically spaced members is disposed in a space between the rear inner housing region 104c and the rear outer housing region 102c. This space is partly defined by a projection 102c2 formed on the rear outer housing region 102c. The lower rear elastic member 110c is configured to extend in the longitudinal, vertical and transverse directions.

(47) With this structure, the rear elastic members 110c are disposed between the rear inner housing region 104c and the rear outer housing region 102c in the longitudinal, vertical and transverse directions. Therefore, transmission of vibration from the rear inner housing region 104c to the rear outer housing region 102c is effectively prevented or reduced in all directions.

(48) As an alternative to the above-described arrangement, the rear elastic members 110c may be disposed at a boundary between the rear inner housing region 104c and the intermediate inner housing region 104b and a boundary between the rear outer housing region 102c and the intermediate outer housing region 102b. Further, the rear elastic members 110c may be disposed between the intermediate inner housing region 104b and the intermediate outer housing region 102b.

(49) The intermediate inner housing region 104b shown in FIGS. 2 to 4 is formed of synthetic resin so as to be imparted with flexibility. Thus, the intermediate inner housing region 104b is configured to serve as the intermediate elastic member 110b as well. The intermediate elastic member 110b is an example embodiment that corresponds to the “intermediate elastic member” according to the present invention. The intermediate elastic member 110b extends in the longitudinal direction and can deform around its longitudinally extending axis. Therefore, transmission of vibration from the front inner housing region 104a to the rear inner housing region 104c is effectively prevented or reduced.

(50) (Driving Mechanism)

(51) The structure of the driving mechanism 120 is now described with reference to FIGS. 1, 11 to 13. FIG. 11 is an enlarged sectional view showing the driving mechanism 120. FIG. 12 is a sectional view taken along line VIII-VIII in FIG. 1. FIG. 13 is a sectional view taken along line IX-IX in FIG. 1.

(52) As shown in FIGS. 1 and 11, the driving mechanism 12 mainly includes an eccentric shaft 121, a drive bearing 122, a driven arm 123 and a spindle 124. The spindle 124 is an example embodiment that corresponds to the “spindle” according to the present invention. The spindle 124 is cylindrically formed, and a clamp shaft 127 is removably fitted in the spindle 124. The oscillating tool 100 has a lock mechanism 130 for locking and unlocking the clamp shaft 127 with respect to the oscillating tool 100, and a lock operation mechanism 150 with which the lock mechanism 130 is manually operated by a user.

(53) As shown in FIG. 11, the driving mechanism housing 105 has a first driving mechanism housing 105A and a second driving mechanism housing 105B, and the driving mechanism 120, the lock mechanism 130 and the lock operation mechanism 150 are disposed between the first driving mechanism housing 105A and the second driving mechanism housing 105B. The first driving mechanism housing 105A and the second driving mechanism housing 105B are integrally connected by fastening members 105a. The fastening members 105a are screws.

(54) As shown in FIG. 11, the direction of a rotation axis of the spindle 124 is parallel to the output shaft 115a of the brushless motor 115. The eccentric shaft 121 is mounted onto an end of the output shaft 115a of the brushless motor 115 and rotatably supported by an upper bearing 121b and a lower bearing 121c. The bearings 121b, 121c are held by the driving mechanism housing 105.

(55) As shown in FIGS. 11 and 12, the driven arm 123 has an arm part 123a and a fixed part 123b. The arm part 123a is configured to be held in contact with the outer periphery of the drive bearing 122 mounted on an eccentric part 121a of the eccentric shaft 121. The fixed part 123b is configured to surround a prescribed region of the spindle 124 and fixed to the spindle 124. The driven arm 123 and the spindle 124 are arranged below the brushless motor 115. With this structure, the spindle 124 can be shortened in the vertical direction. Further, with this structure, the blade 145 can be arranged closer to the driven arm 123 in the vertical direction. Therefore, a couple of force which is generated according to the distance between the driven arm 123 and the blade 145 is reduced. Thus, vibration which is caused by machining the workpiece with the blade 145 is reduced.

(56) As shown in FIG. 11, the spindle 124 has a flange-like tool holding part 126 for holding the blade 145 in cooperation with the clamp shaft 127. The spindle 124 is rotatably supported by an upper bearing 124a and a lower bearing 124b.

(57) The clamp shaft 127 is a generally columnar member configured to be inserted through the spindle 124 as shown in FIG. 11. The clamp shaft 127 has an upper end part having an engagement groove part 127a and a lower end part having a flange-like clamp head 127b. When the clamp shaft 127 is inserted through the spindle 124 and the engagement groove part 127a is held by the lock mechanism 130, the blade 145 is held between the clamp head 127b and the tool holding part 126.

(58) When the brushless motor 115 is driven and the output shaft 115a is rotated, the eccentric part 121a of the eccentric shaft 121 and the drive bearing 122 rotate around the motor rotation axis. Thus, the driven arm 123 is driven to swing on the rotation axis of the spindle 124. As a result, the blade 145 held between the spindle 124 and the clamp shaft 127 is driven to swing to perform a prescribed operation (such as a cutting operation).

(59) (Lock Mechanism)

(60) The lock mechanism 130 shown in FIG. 11 serves to hold the clamp shaft 127

(61) As shown in FIG. 11, the lock mechanism 130 mainly includes a clamp member 131, a collar member 135, a first coil spring 134, a lid member 137 and a bearing 135b. These components of the lock mechanism 130 form a lock mechanism assembly. Further, the lock mechanism 130 has a biasing mechanism 140 which biases the clamp shaft 127 upward. The biasing mechanism 140 mainly includes a support member 141 and a second coil spring 142.

(62) As shown in FIG. 11, the support member 141 has a generally cylindrical hollow shape through which the clamp shaft 127 is inserted. The support member 141 is rotatably supported by the bearing 124a. The bearing 124a is configured to support both the spindle 124 and the support member 141. With this structure, the number of bearings can be reduced, and the oscillating tool 100 can be shortened in the vertical direction. The support member 141 is inserted through the second coil spring 142. The support member 141 has a flange-like lower part configured to be held in contact with a lower end of the second coil spring 142. Further, the support member 141 has an upper end configured to support the clamp member 131 when the clamp member 131 is placed in a position (disengaging position) for replacement of the blade 145.

(63) As shown in FIG. 11, the lock mechanism 130 is disposed between the upper end of the support member 141 and the first driving mechanism housing 105A in the direction of the rotation axis of the spindle 124. The lock mechanism 130 and the spindle 124 are configured independently and arranged apart from each other, so that the lock mechanism 130 can be designed without depending on the design of the spindle 124.

(64) As shown in FIG. 11, the clamp member 131 consists of a pair of members which hold the engagement groove part 127a of the clamp shaft 127 in a radial direction of the clamp shaft 127. Each clamp member 131 is configured to be movable in a direction crossing the vertical direction. Further, a plurality of ridge parts are formed on an inner surface region of the clamp member 131 facing the clamp shaft 127 and can engage with the engagement groove part 127a of the clamp shaft 127. Further, as shown in FIG. 11, the clamp member 131 has two clamp member inclined parts 131a inclined with respect to the vertical direction.

(65) As shown in FIG. 11, the first coil spring 134 is disposed between each of the clamp members 131 and the lid member 137. The first coil spring 134 biases the clamp member 131 downward so as to stabilize the attitude of the clamp member 131.

(66) As shown in FIG. 11, the collar member 135 serves to control clamping of the clamp shaft 127 by the clamp members 131. The collar member 135 has a hole in which the clamp members 131 are disposed and through which the clamp shaft 127 is inserted. The bearing 135b for rotatably supporting the collar member 135 is disposed in an outside region of the collar member 135. The bearing 135b is configured to be slidable with respect to the second driving mechanism housing 105B.

(67) With this structure, the lock mechanism assembly is allowed to move in the direction of the rotation axis of the spindle 124. The collar member 135 has two collar member inclined parts 135a inclined with respect to the rotation axis direction of the spindle 124. The collar member inclined parts 135a and the clamp member inclined parts 131a are configured to slide in contact with each other. Therefore, the same number of the clamp member inclined parts 131a as the collar member inclined parts 135a are provided.

(68) As shown in FIG. 11, the collar member 135 is biased by the second coil spring 142 and the clamp member 131 is biased by the first coil spring 134, so that the collar member inclined parts 135a come in contact with the clamp member inclined parts 131a. Thus, the clamp member 131 is moved inward in the radial direction of the clamp shaft 127. As a result, the two clamp members 131 hold the clamp shaft 127 while the ridge parts of the clamp members 131 are engaged with the engagement groove part 127a of the clamp shaft 127. The clamp shaft 127 is held between the clamp members 131 and biased upward by the second coil spring 142. In this manner, the blade 145 is held between the clamp head 127b of the clamp shaft 127 and the tool holding part 126 of the spindle 124.

(69) (Lock Operation Mechanism)

(70) The lock operation mechanism 150 shown in FIGS. 11 and 13 is configured to operate the lock mechanism 130. More specifically, the lock operation mechanism 150 is configured to move the collar member 135 in the vertical direction. By the movement of the collar member 135 in the vertical direction, the clamp member 131 is switched to be engaged with and disengaged from the clamp shaft 127.

(71) As shown in FIGS. 11 and 13, the lock operation mechanism 150 mainly includes a handle part 151 which is operated by a user and a pivot shaft 151a which is interlocked with the handle part 151. As shown in FIG. 13, the pivot shaft 151a is arranged to extend through the driving mechanism housing 105 between the lid member 137 and the first driving mechanism housing 105A. A pair of cams 151b are provided on both ends of the pivot shaft 151a and configured to come in contact with the collar member 135. An eccentric shaft 151c is provided between the cams 151b.

(72) FIGS. 11 and 13 show the state in which the blade 145 is attached to the oscillating tool 100. The cams 151b are configured not to come in contact with the collar member 135 in this state. In this state, the collar member 135 is biased upward by the second coil spring 142, and the collar member inclined parts 135a come in contact with the clamp member inclined parts 131a. As a result, the two clamp members 131 are moved toward the clamp shaft 127 and hold the clamp shaft 127. Further, the eccentric shaft 151c is placed apart from the first driving mechanism housing 105A. The upper end of the support member 141 is held in non-contact with the clamp members 131.

(73) As described above, in this state, the position of the clamp shaft 127 defines a holding position for holding the blade 145, the position of the clamp member 131 defines an engaging position for engaging with the clamp shaft 127, and the position of the collar member 135 defines a maintaining position for maintaining the clamp member 131 in the engaging position.

(74) In order to remove the blade 145 from the oscillating tool 100, the user turns the handle part 151, so that the pivot shaft 151a is rotated. In this state, the cams 151b come into contact with the collar member 135 and move the collar member 135 downward against the biasing force of the second coil spring 142. As a result, the upper end of the support member 141 comes into contact with the clamp members 131 and the clamp members 131 are moved upward with respect to the collar member 135.

(75) When the clamp members 131 are moved upward with respect to the collar member 135, the clamp member inclined parts 131a are disengaged from the collar member inclined parts 135a, so that the clamp members 131 are allowed to move in a direction away from the clamp shaft 127. Specifically, the force of clamping the clamp shaft 127 with the clamp members 131 is reduced. In this state, the clamp shaft 127 can be pulled out downward and removed from the spindle 124. By thus releasing the clamp shaft 127, the blade 145 is also released, so that the tool accessory or blade 145 can be replaced.

(76) In this state, the position of the collar member 135 defines an allowing position for allowing the clamp member 131 to move to a disengaging position, the position of the clamp member 131 defines the disengaging position for disengaging from the clamp shaft 127, and the position of the clamp shaft 127 defines a releasing position for releasing the blade 145.

(77) Further, the eccentric shaft 151c is placed in contact with the first driving mechanism housing 105A.

(78) (Operation for Machining)

(79) Operation of the oscillating tool 100 for machining is now described with reference to FIGS. 1, 2 and 11. When a user holds the thin part 107 of the intermediate outer housing region 102b and turns on the slide switch 108, the controller 180 rotationally drives the brushless motor 115. Thus, the drive bearing 122 is rotated together with the eccentric shaft 121. As a result, the drive bearing 122 drives the driven arm 123, so that the blade 145 swings on the rotation axis of the spindle 124 together with the spindle 124. In this state, machining operation can be performed when the blade 145 is placed in contact with a workpiece by the user.

(80) In machining, due to the structure in which the rear inner housing region 104c has the controller 180 disposed therein and the battery 190 mounted thereto, the moment of inertia of the inner housing 104 is increased, so that vibration of the inner housing 104 is reduced. Furthermore, this structure prevents malfunctioning which may otherwise be caused by repeated contact and separation between the feeding terminal of the battery 190 and the receiving terminal of the battery mounting part 109 in a short time, and prevents welding between the feeding terminal and the receiving terminal which may be caused by the progress of such malfunctioning.

(81) Further, due to the structure in which the front elastic members 110a connect the front inner housing region 104a and the front outer housing region 102a, the intermediate elastic member 110b connect the front inner housing region 104a and the rear inner housing region 104c, and the rear elastic members 110c connect the rear inner housing region 104c and the rear outer housing region 102c, vibration caused in the front inner housing region 104a is prevented from being transmitted to the outer housing 102. Therefore, the user can comfortably perform machining operation using the oscillating tool 100 having the vibration reducing structure.

(82) Further, when the brushless motor 115 is rotationally driven, the cooling fan 118 is rotationally driven. Then, air is taken in from the body inlet 101d, led into the inner housing 104 through the inlets 104c1 and discharged from the outlets 104a1 via the air passage 119. By this air flow, the controller 180 arranged immediately downstream of the inlets 104c1 and the brushless motor 115 are cooled.

Second Embodiment

(83) An oscillating tool 200 according to a second embodiment of the present invention is now described with reference to FIGS. 14 to 17. The oscillating tool 200 of the second embodiment is different from the oscillating tool 100 of the first embodiment in the structure of the inner housing 104 and the intermediate elastic member.

(84) (Inner Housing)

(85) As shown in FIGS. 14 to 16, the inner housing 104 of the oscillating tool 200 includes the driving mechanism housing 105, the first inner housing 104A, the second inner housing 104B, a fifth inner housing 104E and a sixth inner housing 104F. FIG. 15 is a sectional view taken along line X-X in FIG. 14, and FIG. 16 is a sectional view taken along line XI-XI in FIG. 14.

(86) The first, second, fifth and sixth inner housings 104A, 104B, 104E, 104F are formed of synthetic resin. The intermediate inner housing region 104b mainly includes the fifth inner housing 104E, and the rear inner housing region 104c mainly includes the sixth inner housing 104F.

(87) The fifth inner housing 104E and the driving mechanism housing 105 are integrally connected by a fastening member 104e shown in FIG. 14. Further, a rear end of the second inner housing 104B and a front end of the fifth inner housing 104E are held in contact with each other. With this structure, the driving mechanism housing 105 and the first, second and fifth inner housings 104A, 104B, 104E are integrated together.

(88) As shown in FIGS. 14 and 15, an enlarged diameter region is formed in a rear region of the sixth inner housing 104F. The controller 180 is disposed within the enlarged diameter region, and the battery mounting part 109 is formed in the enlarged diameter region.

(89) As shown in FIG. 16, inlets 104c1 are formed in the rear inner housing region 104c, and outlets 104a1 are formed in the front inner housing region 104a. Further, as shown in FIG. 14, a space part between the intermediate outer housing region 102b and the intermediate inner housing region 104b forms an air passage 119. As shown in FIGS. 14 and 15, a body inlet 101d is formed between the rear outer housing region 102c and the rear inner housing region 104c.

(90) With this structure, air is caused to flow by rotational driving of the cooling fan 118, taken in from the body inlet 101d and discharged from the outlets 104a1 via the inlets 104c1, the controller 180, the air passage 119 and the brushless motor 115. By this air flow, the controller 180 and the brushless motor 115 are efficiently cooled. Further, a connecting part for electrically connecting the brushless motor 115 and the controller 180 is provided in the air passage 119.

(91) (Elastic Members)

(92) Like in the above-described oscillating tool 100, in the oscillating tool 200, the front inner housing region 104a and the front outer housing region 102a are connected by the front elastic members 110a. Further, as shown in FIG. 17, the sixth inner housing 104F and the rear outer housing region 102c are connected by the rear elastic members 110c.

(93) As shown in FIGS. 14, 15 and 17, an intermediate elastic member 110d is disposed between the fifth inner housing 104E and the sixth inner housing 104F. The intermediate elastic member 110d includes two cylindrical rubber elastic elements. As shown in FIG. 14, a rear end part of the fifth inner housing 104E is inserted into the intermediate elastic member 110d, and the outer periphery of the intermediate elastic member 110d is fitted in contact with a cylindrical elastic-member mounting part of the sixth inner housing 104F. With this structure, the intermediate elastic member 110d is held in close contact with both the fifth and sixth inner housings 104E, 104F and integrally connects the fifth and sixth inner housings 104E, 104F. The intermediate elastic member 110d is an example embodiment that corresponds to the “intermediate elastic member” according to the present invention. The intermediate elastic member 110d effectively prevents vibration caused in the front inner housing region 104a from being transmitted to the rear inner housing region 104c in all directions.

(94) (Operation for Machining)

(95) Like the oscillating tool 100, the oscillating tool 200 drives the blade 145 to swing by using the brushless motor 115 and the driving mechanism 120 (which are shown in FIG. 14) to perform a machining operation.

(96) In machining, due to the structure in which the front elastic members 110a connect the front inner housing region 104a and the front outer housing region 102a, the intermediate elastic member 110d connects the front inner housing region 104a and the rear inner housing region 104c, and the rear elastic members 110c connect the rear inner housing region 104c and the rear outer housing region 102c, vibration caused in the front inner housing region 104a is prevented from being transmitted to the outer housing 102.

(97) Therefore, the user can perform machining operation using the oscillating tool 200 having the vibration reducing structure.

(98) Further, when the brushless motor 115 is rotationally driven, the cooling fan 118 is rotationally driven. Then, air is taken in from the body inlet 101d and flows through the inlets 104c1, the air passage 119 and the outlets 104a1. By this air flow, the controller 180 and the brushless motor 115 are cooled.

(99) In the above-described embodiments, the oscillating tools 100, 200 are described as a representative example of the work tool, but the work tool is not limited to an electric oscillating tool. For example, the present invention may also be applied to a work tool such as a grinder and a circular saw in which the tool accessory rotates. Further, any number of the front elastic members 110a, the intermediate elastic members 110b (110d) and the rear elastic members 110c may be provided.

(100) In the above-described embodiments, the brushless motor 115 is powered by the battery 190, but the oscillating tools 100, 200 may be configured to use an external power source in place of the battery 190. Specifically, a power cable which can be connected to the external power source and electrically connected to the controller 180 may be connected to the rear outer housing region 102c. When a direct current motor is used as the brushless motor 115, the controller 180 may be configured to have a function as a converter for converting an alternate current supplied from the external power source into a direct current. An alternate current motor may be used as the brushless motor 115. In this case, it is not necessary for the controller 180 to have a function as a converter.

(101) In view of the object of the above-described invention, work tools according the present invention can have the following features. Each feature may be used alone or in combination with others, or in combination with the claimed invention.

(102) (Aspect 1-1)

(103) A body inlet is formed between a rear end part of the outer housing and a rear end part of the inner housing in a longitudinal direction when an extending direction of the elongate outer housing is defined as the longitudinal direction.

(104) (Aspect 1-2)

(105) The front elastic member comprises a plurality of elastic elements spaced apart from each other in a transverse direction, when an extending direction of the rotation axis of the spindle is defined as a vertical direction and a direction crossing the longitudinal direction and the vertical direction is defined as the transverse direction.

(106) (Aspect 1-3)

(107) The rear elastic member comprises a plurality of elastic elements spaced apart from each other in the vertical direction.

(108) (Aspect 2-1)

(109) A work tool, which performs a prescribed operation on a workpiece by driving a tool accessory, comprising:

(110) a housing extending in an elongate form,

(111) a brushless motor,

(112) a controller for controlling driving of the brushless motor, and

(113) a spindle having a rotation axis extending in parallel to a rotation output shaft of the brushless motor and configured to be rotated on the rotation axis within a prescribed angular range via the brushless motor to drive the tool accessory, wherein:

(114) in a longitudinal direction which is defined as an extending direction of the elongate housing, the housing has a front housing region that defines a front region of the housing, a rear housing region that defines a rear region of the housing, and an intermediate housing region that defines an intermediate part between the front housing region and the rear housing region,

(115) at least the brushless motor is disposed in the front inner housing region, and

(116) the controller is disposed in the rear inner housing region.

(117) (Aspect 2-2)

(118) The work tool as defined in the aspect 2-1, further comprising:

(119) an outer housing,

(120) an inner housing comprising the housing and housed within the outer housing,

(121) an elastic member configured to elastically connect the outer housing and the inner housing to prevent vibration caused in the inner housing from being transmitted to the outer housing.

(122) (Aspect 2-3)

(123) The work tool as defined in the aspect 2-1 or 2-2, further comprising an inlet formed in the rear housing region, an outlet formed in the front housing region and an air passage formed within the intermediate housing region, wherein the controller and the brushless motor are arranged on an air flow path extending from the inlet to the outlet via the air passage.

(124) (Aspect 2-4)

(125) The work tool as defined in the aspect 2-2, further comprising an inlet formed in the rear housing region, an outlet formed in the front housing region and an air passage formed between the intermediate housing region and the outer housing, wherein the controller and the brushless motor are arranged on an air flow path extending from the inlet to the outlet via the air passage.

(126) (Aspect 2-5)

(127) The work tool as defined in the aspect 2-3 or 2-4, wherein the controller is disposed within the rear inner housing region and immediately downstream of the inlet through which air is sucked in.

(128) (Aspect 2-6)

(129) The work tool as defined in any one of the aspects 2-3 to 2-5, further comprising a connecting part for electrically connecting the controller and the brushless motor, wherein the connecting part is at least partly arranged in the air passage.

(130) (Aspect 2-7)

(131) The work tool as defined in any one of the aspects 2-1 to 2-6, wherein a body inlet is formed between a rear end part of the outer housing and a rear end part of the housing (or inner housing).

(132) (Aspect 2-8)

(133) The work tool as defined in any one of the aspects 2-1 to 2-7, wherein the front elastic member comprises a plurality of elastic elements spaced apart from each other in a transverse direction, when an extending direction of the rotation axis of the spindle is defined as a vertical direction and a direction crossing the longitudinal direction and the vertical direction is defined as the transverse direction.

(134) (Aspect 2-9)

(135) The work tool as defined in any one of the aspects 2-1 to 2-8, wherein the rear elastic member comprises a plurality of elastic elements spaced apart from each other in the vertical direction.

Correspondences Between the Features of the Embodiments and the Features of the Invention

(136) Correspondences between the features of the embodiments and the features of the invention are as follows. The above-described embodiments are representative examples for embodying the present invention, and the present invention is not limited to the structures that have been described as the representative embodiments.

(137) The oscillating tool 100, 200 is an example embodiment that corresponds to the “work tool” according to the present invention. The blade 145 is an example embodiment that corresponds to the “tool accessory” according to the present invention. The outer housing 102 and the inner housing 104 are example embodiments that correspond to the “outer housing” and the “inner housing”, respectively, according to the present invention. The front outer housing region 102a, the rear outer housing region 102c and the intermediate outer housing region 102b are example embodiments that correspond to the “front outer housing region”, the “rear outer housing region” and the “intermediate outer housing region”, respectively, according to the present invention. The front inner housing region 104a, the intermediate inner housing region 104b and the rear inner housing region 104c are example embodiments that correspond to the “front inner housing region”, the “intermediate inner housing region” and the “rear inner housing region”, respectively, according to the present invention. The thin part 107 is an example embodiment that corresponds to the “thin part” according to the present invention. The brushless motor 115 is an example embodiment that corresponds to the “brushless motor” according to the present invention. The battery 190 and the battery mounting part 109 are example embodiments that correspond to the “battery” and the “battery mounting part”, respectively, according to the present invention. The inlet 104c1, the outlet 104a1, the cooling fan 118 and the air passage 119 are example embodiments that correspond to the “inlet”, the “outlet”, the “cooling fan” and the “air passage”, respectively, according to the present invention. The connecting part is an example embodiment that corresponds to the “connecting part” according to the present invention. The front elastic member 110a is an example embodiment that corresponds to the “front elastic member” according to the present invention. The rear elastic member 110c is an example embodiment that corresponds to the “rear elastic member” according to the present invention. The intermediate elastic member 110b, 110d is an example embodiment that corresponds to the “intermediate elastic member” according to the present invention. The spindle 124 is an example embodiment that corresponds to the “spindle” according to the present invention.

DESCRIPTION OF THE NUMERALS

(138) 100,200 oscillating tool (work tool) 101 body housing 101a front body housing region 101b intermediate body housing region 101c rear body housing region 101d body inlet 102 outer housing 102A first outer housing 102B second outer housing 102a front outer housing region 102b intermediate outer housing region 102c rear outer housing region 102c1 projection 102c2 projection 102d fastening member 103 intervening member 103a front intervening member region 103a1 projection 103b intermediate intervening member region 103c rear intervening member region 103d fastening member 104 inner housing 104A first inner housing 104A1 opening 104B second inner housing 104C third inner housing 104D fourth inner housing 104E fifth inner housing 104F sixth inner housing 104a front inner housing region 104a1 outlet 104b intermediate inner housing region 104c rear inner housing region 104c1 inlet 104d fastening member 104e fastening member 104f fastening member 105 driving mechanism housing 105A first driving mechanism housing 105B second driving mechanism housing 105a fastening member 107 thin part 108 slide switch 109 battery mounting part 110a front elastic member 110b intermediate elastic member 110c rear elastic member 110d intermediate elastic member 115 brushless motor 115a output shaft 118 cooling fan 119 air passage 120 driving mechanism 121 eccentric shaft 121a eccentric part 121b bearing 121c bearing 122 drive bearing 123 driven arm 123a arm part 123b fixed part 124 spindle 124a bearing 124b bearing 126 tool holding part 127 clamp shaft (tool accessory holding member) 127a engagement groove part 127b clamp head 130 lock mechanism 131 clamp member 131a clamp member inclined part 134 first coil spring 135 collar member 135a collar member inclined part 135b bearing 137 lid member 140 biasing mechanism 141 support member 141a coil spring support part 141b clamp member support part 142 second coil spring 145 blade (tool accessory) 150 lock operation mechanism 151 handle part 151a pivot shaft 151b cam 151c eccentric shaft 180 controller 190 battery